Co-reporter:Jingrun Zhu, Xiaoling Yang, Yihua Zhu, Yuanwei Wang, Jin Cai, Jianhua Shen, Luyi Sun, and Chunzhong Li
The Journal of Physical Chemistry Letters September 7, 2017 Volume 8(Issue 17) pp:4167-4167
Publication Date(Web):August 18, 2017
DOI:10.1021/acs.jpclett.7b01820
Here we report the room-temperature, atmospheric synthesis of Mn-doped cesium lead halide (CsPbX3) perovskite quantum dots (QDs). The synthesis is performed without any sort of protection, and the dual-color emission mechanism is revealed by density functional theory. The Mn concentration reaches a maximum atomic percentage of 37.73 at%, which is significantly higher in comparison to those achieved in earlier reports via high temperature hot injection method. The optical properties of as-prepared nanocrystals (NCs) remain consistent even after several months. Therefore, red-orange LEDs were fabricated by coating the composite of PS and as-prepared QDs onto ultraviolet LED chips. Additionally, the present approach may open up new methods for doping other ions in CsPbX3 QDs under room temperature, the capability of which is essential for applications such as memristors and other devices.
Co-reporter:Shunan Zhao;Jianfei Huang;Yanyan Liu;Jianhua Shen;Hao Wang;Xiaoling Yang;Chunzhong Li
Journal of Materials Chemistry A 2017 vol. 5(Issue 8) pp:4207-4214
Publication Date(Web):2017/02/21
DOI:10.1039/C6TA10749D
In this study, excellent full water splitting achieved with a rationally structured multimetallic Ni–Mo/Cu nanowire free-standing electrode prepared via scalable electrochemistry is reported. By combining a conductive nanostructured scaffold and highly active outer layers, the as-prepared Ni–Mo/Cu nanowires deliver superior hydrogen and oxygen evolution performance. To achieve a 20 mA cm−2 catalytic current in a 1 M KOH electrolyte, the NM-CNW requires an overpotential of only 152 mV for hydrogen evolution and 280 mV for oxygen evolution. When assembled into a full electrolyzer, the Ni–Mo/Cu nanowires can drive full water splitting at nearly 100% faradaic efficiency steadily up to 12 h without any significant performance decay, and afford a catalytic current close to that of the state-of-the-art Pt–RuO2 system over long-term operation.
Co-reporter:Hao Wang;Jianhua Shen;Jianfei Huang;Tengjing Xu;Jingrun Zhu;Chunzhong Li
Nanoscale (2009-Present) 2017 vol. 9(Issue 43) pp:16817-16825
Publication Date(Web):2017/11/09
DOI:10.1039/C7NR06665A
CO oxidation is a typical heterogeneous catalytic reaction. Development of active and stable low-temperature CO oxidation catalysts has been one of the hot topics in the field of catalysis. In this work, we explored the catalytic application of a series of Au catalysts supported on CeO2 foam using a modified deposition–precipitation method for CO oxidation. Among them, the catalyst with 1.1% Au loading content showed the highest catalytic activity, leading to the CO total conversion at 20 °C. Based on the strategy of stepwise reduction of Au loading content, we finally obtained the atomically monodisperse Au/CeO2 catalyst with high stability and strong resistance to elevated temperature, on which in situ DRIFTS analysis and DFT study were further performed to study the possible reactive site. Our results implied that the Au atoms on the CeO2 foam are the more stable sites for CO adsorption on the catalysts.
Co-reporter:Yuanwei Wang;Xiaoling Yang;Jianhua Shen;Jingrun Zhu;Shaohong Qian;Chunzhong Li
Chinese Journal of Chemistry 2017 Volume 35(Issue 6) pp:949-956
Publication Date(Web):2017/06/01
DOI:10.1002/cjoc.201600771
AbstractSingle-crystal-like TiO2 mesoporous microspheres have been reported with high photocatalytic activity under ultraviolet light (UV light) because of their high specific surface areas and single-crystal-like channel walls. In this work, plasmonic gold nanoparticles (Au NPs) and β-NaYF4: Yb3+, Er3+ upconversion nanoparticles (UCNPs) were composited with single-crystal-like TiO2 mesoporous microspheres through a series of facile approaches, aiming at broadening response region of solar light from UV to visible and near infrared light and enhancing the photocatalytic activity further. The structure was rationally designed by modifying the pore size of TiO2 mesoporous microspheres so as to anchor plasmonic Au NPs, and covering β-NaYF4: Yb3+, Er3+ with SiO2 in order to embed UCNPs into TiO2 mesoporous microspheres via hydrophilic interaction. This work studied the attribution of Au NPs and UCNPs to photocatalysis and found out that combining Au NPs and certain amount of UCNPs with single-crystal- like TiO2 mesoporous microspheres in a monolithic architecture would bring enhanced broadband photocatalytic activity under simulated solar light. Consequently, the composite photocatalyts containing 150 mg UCNPs showed a significant enhancement in reaction rate, which was 36.02% higher than commercial P25 and 85.09% higher than pure TiO2 mesoporous microspheres under simulated solar light.
Co-reporter:Jianhua Shen, Ying Zhou, Jianfei Huang, Yihua Zhu, Jingrun Zhu, Xiaoling Yang, Wei Chen, Yifan Yao, Shaohong Qian, Hao Jiang, Chunzhong Li
Applied Catalysis B: Environmental 2017 Volume 205(Volume 205) pp:
Publication Date(Web):15 May 2017
DOI:10.1016/j.apcatb.2016.12.010
•Multifunctional Fe3O4@TiO2@Ag-Au microspheres (MS) are prepared.•The MS exhibit excellent catalytic activity attached with in-situ SERS monitoring.•They have good photocatalytic performance and reusability by magnetic separation.•The FDTD simulation shows the significantly increases of the ‘hot spot’.Multifunctional Fe3O4@TiO2@Ag-Au microspheres (MS) were synthesized by grafting Ag nanoparticles onto 3-Aminopropyltrimethoxysilane (APTMS) modified Fe3O4@TiO2 MS, followed by galvanic replacement approach to fabricate Ag-Au bimetallic nanostructures with variable bimetallic molar ratios. The composite with Au-to-Ag ratio of 1:1 exhibits optimal catalytic activity for reduction of 4-nitrophenol (4-NP). Furthermore, finite-difference time-domain (FDTD) simulation study shows that incorporating Au-Ag bimetallic nanostructures onto Fe3O4@TiO2 MS significantly increases the effect of the ‘hot spot’, offering stronger electromagnetic field enhancements. Indeed, the Fe3O4@TiO2@Ag-Au was demonstrated to be an excellent substrate material for in-situ surface-enhanced Raman scattering (SERS) monitoring of the reaction process. Combined with its good magnetic and photocatalytic performance allowing facile recovery, Fe3O4@TiO2@Ag-Au MS shows great potential for multifunctional platform for simultaneous catalysis and in-situ reaction monitoring.Download high-res image (142KB)Download full-size image
Co-reporter:Yuanwei Wang;Jianfei Huang;Jin Cai;Jingrun Zhu;Xiaoling Yang;Jianhua Shen;Chunzhong Li
Nanoscale Horizons (2016-Present) 2017 vol. 2(Issue 4) pp:225-232
Publication Date(Web):2017/06/26
DOI:10.1039/C7NH00057J
CsPbBr3 perovskite quantum dots (CPBQDs) have exhibited excellent optical properties, which implies their potential as an appealing candidate for fluorescence resonance energy transfer (FRET) based detection. In this work, in order to enhance the subsurface concentration of CPBQDs, which is important for the efficiency of FRET detection, a nanoscale polymethyl methacrylate (PMMA) fiber membrane (d ≈ 400 nm) encapsulated with CPBQDs (CPBQDs/PMMA FM) is fabricated using an electrospinning method. The CPBQD/PMMA FM possesses comparable optical properties to CPBQDs, high quantum yields (88%) and a narrow half-peak width (∼14 nm). The sensing of trypsin is realized via the cleavage of peptide CF6 (Cys–Pro–Arg–Gly–R6G) and an extremely low detection limit of 0.1 μg mL−1 has been reached. Besides, owing to the high efficiency FRET process between the CPBQD/PMMA FM and cyclam–Cu2+, an unprecedented detection limit of Cu2+ has been pushed to 10−15 M. Furthermore, the pH value can be confirmed by the membrane in 10 ppb hydrazide R6G ethanol solution. The excellent optical characteristics of CPBQDs, high CPBQD subsurface concentration of the CPBQD/PMMA FM and robust durability of the PMMA coating all contribute to the outstanding sensitivity and stable detection performance of the CPBQD/PMMA FM.
Co-reporter:Xueqin Li;Changlong Hao;Bochong Tang;Yue Wang;Mei Liu;Yuanwei Wang;Chenguang Lu;Zhiyong Tang
Nanoscale (2009-Present) 2017 vol. 9(Issue 6) pp:2178-2187
Publication Date(Web):2017/02/09
DOI:10.1039/C6NR08987A
Due to their high specific surface area and good electric conductivity, nitrogen-doped porous carbons (NPCs) and carbon nanotubes (CNTs) have attracted much attention for electrochemical energy storage applications. In the present work, we firstly prepared MWCNT/ZIF-8 composites by decoration of zeolitic imidazolate frameworks (ZIF-8) onto the surface of multi-walled CNTs (MWCNTs), then obtained MWCNT/NPCs by the direct carbonization of MWCNT/ZIF-8. By controlling the reaction conditions, MWCNT/ZIF-8 with three different particle sizes were synthesized. The effect of NPCs size on capacitance performance has been evaluated in detail. The MWCNT/NPC with large-sized NPC (MWCNT/NPC-L) displayed the highest specific capacitance of 293.4 F g−1 at the scan rate of 5 mV s−1 and only lost 4.2% of capacitance after 10 000 cyclic voltammetry cycles, which was attributed to the hierarchically structured pores, N-doping and high electrical conductivity. The studies of symmetric two-electrode supercapacitor cells also confirmed MWCNT/NPC-L as efficient electrode materials that have good electrochemical performance, especially for high-rate applications.
Co-reporter:Xiaoling Yang;Chengjia Li;Jianfei Huang;Yanyan Liu;Wei Chen;Jianhua Shen;Chunzhong Li
RSC Advances (2011-Present) 2017 vol. 7(Issue 25) pp:15168-15175
Publication Date(Web):2017/03/06
DOI:10.1039/C7RA00486A
Designing high-efficiency heterogeneous photo-assisted Fenton catalysts is the key to harnessing solar energy for promoting the Fenton process in water treatment. Herein we developed nitrogen-doped Fe3C@C particles by thermally treating Fe3O4 precursor with dicyandiamide. The as-prepared Fe–N–C hybrid material was comprehensively characterized by electron microscopy, various spectroscopic techniques and so forth to confirm the compositions and structures. The band gap of nitrogen-doped Fe3C@C particles was about 1.6 eV. Methylene blue was used as a model organic contaminant to test the photo-assisted Fenton activity of the nitrogen-doped Fe3C@C particles, with optimal dosages of H2O2 and the catalyst itself, which showed excellent efficiency in removing the model contaminant, demonstrating that the as-prepared hybrids can work as a highly efficient photo-assisted Fenton catalyst.
Co-reporter:Jianfei Huang, Shunan Zhao, Wei Chen, Ying Zhou, Xiaoling Yang, Yihua Zhu and Chunzhong Li
Nanoscale 2016 vol. 8(Issue 11) pp:5810-5814
Publication Date(Web):06 Nov 2015
DOI:10.1039/C5NR06512G
This communication reports fully electrochemical nanoengineering toward three-dimensionally grown thorn-like Cu nanowire arrays (CNWAs) as a highly efficient and durable electrocatalyst for hydrazine oxidation. Characterized by substantial negative shifting of the onset potential and an enlarged catalytic current density, the CNWAs afforded greatly enhanced hydrazine oxidation activity, even transcending that of the Pt/C catalyst at a higher reaction rate. The parameters of the electrochemical engineering and metallization methods were found to be essentially influential on the microstructure, and thus the electrocatalytic activity of the CNWAs. The present work typifies a flexible and expandible route toward integrated electrodes of metallic 1D nanostructures which are of interest in advancing the performance of cutting-edge electrochemical applications.
Co-reporter:Yanyan Liu, Hongliang Jiang, Yihua Zhu, Xiaoling Yang and Chunzhong Li
Journal of Materials Chemistry A 2016 vol. 4(Issue 5) pp:1694-1701
Publication Date(Web):06 Jan 2016
DOI:10.1039/C5TA10551J
The development of efficient and cheap bifunctional oxygen electrocatalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) to be applied in rechargeable metal–air batteries and unitized generative fuel cells (URFCs) operated with alkaline electrolytes is highly crucial and challenging. Here we report high-performance bifunctional electrocatalysts of transition metal nanoparticles encapsulated in nitrogen-doped carbon nanotubes (M/N-CNTs, M = Fe, Co, and Ni). The optimized Co/N-CNT hybrid shows the highest efficient bifunctional catalytic activity and excellent stability towards both the ORR and OER. The oxygen electrode activity parameter ΔE (the criteria for judging the overall catalytic activity of bifunctional electrocatalysts) value for Co/N-CNTs is 0.78 V, which surpasses those of Pt/C and RuO2 catalysts and most of the non-precious metal based bifunctional electrocatalysts reported in the previous literature studies. Furthermore, excellent long-term catalytic durability holds great promise in fields of renewable energy applications.
Co-reporter:Yuanwei Wang, Yihua Zhu, Xiaoling Yang, Jianhua Shen, Xueqin Li, Shaohong Qian, Chunzhong Li
Electrochimica Acta 2016 Volume 211() pp:92-100
Publication Date(Web):1 September 2016
DOI:10.1016/j.electacta.2016.05.216
•NaYF4@SiO2crystalsareembeddedintoTiO2mesoporousmicrospheressimplily. (*).•Single-crystal-likeTiO2 mesochannels can increase conductivity and dye adsorption.•NaYF4@SiO2 crystals can increase NIR light upconversion harvest.•N@S@T microspheres can increase light scattering.•The η of the DSSCs with N@S@T-150 is 9.10%, increased by 26.39%.The β-NaYF4:Yb3+,Er3+@SiO2@TiO2 (N@S@T) mesoporous microspheres have been successfully synthesized via a simple evaporation-driven oriented assembly method (EDOA) and applied as multifunctional photoanode films on top of commercial P25 layers in dye-sensitized solar cells (DSSCs). Structural characterizations indicated that N@S@T mesoporous microspheres consisted of uniform β-NaYF4:Yb3+,Er3+ nanocrystals, SiO2 insulating middle shell and single-crystal-like anatase TiO2 shell exposed with (101) facets. Studies revealed that introducing β-NaYF4:Yb3+,Er3+@SiO2 into TiO2 mesoporous microspheres would remarkably enhance the short-circuit current density (Jsc). The SiO2 insulating middle shell played an role in packaging upconvertion nanoparticles (UCNPs) into TiO2 mesoporous microspheres, which were constructed to effectively transfer photoinduced electrons and adsorb more dye molecules, benefitting from their high specific surface areas. DSSCs with the optimal doping amount of UCNPs exhibited the Jsc value of 14.95 mA cm−2 and conversion efficiency of 9.10%, which was a notable enhancement of 26.39% in efficiency compared with commercial P25 based DSSCs. Our work demonstrated that introducing N@S@T into photoanodes was an effective method of improving the overall performance of DSSCs.
Co-reporter:Jianhua Shen, Yihua Zhu, Hao Jiang, Chunzhong Li
Nano Today 2016 Volume 11(Issue 4) pp:483-520
Publication Date(Web):August 2016
DOI:10.1016/j.nantod.2016.07.005
•The recent developments of the synthesis 3D architectures methods from each classical 2D nanosheets were highlighted.•The different fields of application were provided a significant enhancement in the efficacy as compared to 2D analogues.•3D porous structure possess the high electrochemical stability and the promise of high elasticity and mechanical stability.•3D architectures materials will exhibit their unique excellent performances in the industrial production in the future.The discovery of graphene attracted great interest because of the potential prospects of which in both basic and applied research. And other kinds of 2D graphene analogues, including hexagonal BN, carbon nitride, transition metal dichalcogenides, etc. derived from their layered bulk crystals, have also been extensively investigated because of their promising characters and potential applications. It is expected that these 2D nanosheets, in bulk or in composite materials, could maintain their extraordinary properties. However, the irreversible aggregation or accumulating of 2D nanosheets due to the strong van der Waals interactions, extremely decrease their accessible surface area. More recently, with the recognization of the tremendous interest of these 2D structures, scientists noticed that the performance of certain devices could be significantly improved by utilizing 3D architectures and/or aerogels due to the increase of unit activity of the materials. This review summarizes different synthetic process (such as assembly, chemical vapor deposition direct synthesis, in-situ confinement growth and so on) used for preparation of 2D graphene analogues based 3D architectures and/or aerogels containing either any or their composites. And the different fields of application for energy storage (including both supercapacitor and lithium ion battery applications), electrocatalysis, sensing and others are provided a significant enhancement in the efficacy as compared to their 2D analogues or even opened the path to novel application. In addition, some perspectives on the challenges and opportunities in this promising research area are also discussed.
Co-reporter:Jianhua Shen, Yunfeng Li, Yihua Zhu, Xiaoling Yang, Xiuzhong Yao, Jun Li, Guangjian Huang and Chunzhong Li
Journal of Materials Chemistry A 2015 vol. 3(Issue 14) pp:2873-2882
Publication Date(Web):18 Feb 2015
DOI:10.1039/C5TB00041F
The facile fabrication of Gd-labeled superparamagnetic Fe3O4 nanoparticles (NPs) and fluorescent CuInS2 (CIS) quantum dots conjugated with arginine-glycine-aspartic acid (RGD) peptides has been demonstrated, for tri-mode targeted T1-, T2-weighted magnetic resonance (MR) and fluorescence imaging of pancreatic cancer. The core–shell nanocomposites formed are water-dispersible, stable and biocompatible, as confirmed by MTT assay on BXPC-3 cells. Relaxivity measurements show a T1 relaxivity (r1) of 1.56 mM−1 s−1 and a T2 relaxivity (r2) of 23.22 mM−1 s−1, which enable T1- and T2-weighted MR imaging of cancer cells in vitro and in vivo. The MR imaging data clearly indicate that the multifunctional NPs can specifically target cancer cells with αvβ3 integrin over-expression on the cell surface, through a receptor-mediated delivery pathway. The T1-weighted positive and T2-weighted negative enhancement in the MR imaging significantly improves the diagnosis accuracy, and fluorescence imaging of tumor tissue can assist in clinical surgery. These findings suggest that these multifunctional NPs could be used as a platform for bimodal imaging (both MR and fluorescence) in various biological systems.
Co-reporter:Jianfei Huang, Yihua Zhu, Xiaoling Yang, Wei Chen, Ying Zhou and Chunzhong Li
Nanoscale 2015 vol. 7(Issue 2) pp:559-569
Publication Date(Web):10 Nov 2014
DOI:10.1039/C4NR05620E
Convenient determination of glucose in a sensitive, reliable and cost-effective way has aroused sustained research passion, bringing along assiduous investigation of high-performance electroactive nanomaterials to build enzymeless sensors. In addition to the intrinsic electrocatalytic capability of the sensing materials, electrode architecture at the microscale is also crucial for fully enhancing the performance. In this work, free-standing porous CuO nanowire (NW) was taken as a model sensing material to illustrate this point, where an in situ formed 3D CuO nanowire array (NWA) and CuO nanowires pile (NWP) immobilized with polymer binder by conventional drop-casting technique were both studied for enzymeless glucose sensing. The NWA electrode exhibited greatly promoted electrochemistry characterized by decreased overpotential for electro-oxidation of glucose and over 5-fold higher sensitivity compared to the NWP counterpart, benefiting from the binder-free nanoarray structure. Besides, its sensing performance was also satisfying in terms of rapidness, selectivity and durability. Further, the CuO NWA was utilized to fabricate a flexible sensor which showed excellent performance stability against mechanical bending. Thanks to its favorable electrode architecture, the CuO NWA is believed to offer opportunities for building high-efficiency flexible electrochemical devices.
Co-reporter:Xin Jiang, Xiaoling Yang, Yihua Zhu, Yifan Yao, Peng Zhao and Chunzhong Li
Journal of Materials Chemistry A 2015 vol. 3(Issue 5) pp:2361-2369
Publication Date(Web):05 Dec 2014
DOI:10.1039/C4TA05913A
A novel hierarchical nanostructure composed of carbon coated Fe3O4 nanoparticles with seed-like morphology distributed on graphene (denoted as G/Fe3O4@C) is prepared as a high-capacity anode electrode for LIBs. β-FeOOH nanoseeds were first assembled on graphene by solvothermal treatment, followed by coating β-FeOOH nanoseeds with polydopamine via immersion in dopamine aqueous solution. Finally, G/Fe3O4@C is obtained after in situ phase transformation of β-FeOOH into Fe3O4 and simultaneous carbonization of the polydopamine nanocoating through thermal annealing at 500 °C. The thickness of the uniform and continuous carbon layer can be easily tailored by varying the polymerization time and the concentration of dopamine to balance the concurrent needs for high active material content and structural stability. The carbon layer can effectively prevent the agglomeration of Fe3O4 nanoparticles, which enables the reversible conversion reaction between Fe3O4 and lithium, and significantly improves the mechanical stability of electrodes by accommodating volume expansion of Fe3O4 nanoparticles during the electrochemical cycling. Meanwhile, the combination of graphene and the carbon shell improves the electrochemical reaction kinetics of the electrode. As a result, the obtained G/Fe3O4@C nanocomposites with the optimal carbon shell thickness of about 1.2 nm exhibit high reversible capacities with remarkable cyclic retention at different current rates (1344 mA h g−1 after cycling at 0.5 C for 200 cycles, 743 mA h g−1 after further cycling at 2 C for another 200 cycles) and excellent rate performance (150 mA h g−1 at 20 C) as anodes in lithium ion batteries.
Co-reporter:Jianfei Huang, Huailong Li, Yihua Zhu, Qilin Cheng, Xiaoling Yang and Chunzhong Li
Journal of Materials Chemistry A 2015 vol. 3(Issue 16) pp:8734-8741
Publication Date(Web):16 Mar 2015
DOI:10.1039/C5TA00847F
Commercial copper foams have been tailored by a highly scalable method combining room-temperature wet-chemical etching and hydroxide thermolysis into a three-dimensional copper oxide nanowire array–copper (3D-CuONA–Cu) composite with macroporous voids and large-area fur-like nanowire array structures, whose structures and compositions were studied employing electron microscopy, X-ray diffraction (XRD) and Raman spectroscopy. The 3D-CuONA–Cu composite monolith was used as a free-standing electrode for pseudo-capacitive energy storage and enzyme-free H2O2 detection. Thanks to the 3D electrode architecture and the high-density in situ formed electroactive nanoarrays, an enhanced capacitance of 608 mF cm−2 at 2 mV s−1 was achieved, with an 88.6% capacity retention after 4000 cycles observed at the high current density of 30 mA cm−2. For enzyme-free H2O2 sensing, an extraordinary sensitivity of 5.75 mA mM−1 cm−2 and a low detection limit of 0.56 μM were achieved. This prototype sensor also exhibited eligible selectivity and feasibility for real sample analysis.
Co-reporter:Hongliang Jiang, Yihua Zhu, Yunhe Su, Yifan Yao, Yanyan Liu, Xiaoling Yang and Chunzhong Li
Journal of Materials Chemistry A 2015 vol. 3(Issue 24) pp:12642-12645
Publication Date(Web):14 May 2015
DOI:10.1039/C5TA02792F
A bottom-up approach was introduced to prepare nitrogen and phosphorus dual-doped multilayer graphene with a high dopant content and well-developed porosity, which leads to high catalytic activity in the hydrogen evolution reaction with the comparable onset overpotential (0.12 V) and Tafel slope (79 mV per decade) to some of the traditional metallic catalysts.
Co-reporter:Hongliang Jiang, Yifan Yao, Yihua Zhu, Yanyan Liu, Yunhe Su, Xiaoling Yang, and Chunzhong Li
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 38) pp:21511
Publication Date(Web):September 15, 2015
DOI:10.1021/acsami.5b06708
It is highly crucial and challenging to develop bifunctional oxygen electrocatalysts for oxygen reduction reactions (ORRs) and oxygen evolution reactions (OERs) in rechargeable metal-air batteries and unitized regenerative fuel cells (URFCs). Herein, a facile and cost-effective strategy is developed to prepare mesoporous Fe–N-doped graphene-like carbon architectures with uniform Fe3C nanoparticles encapsulated in graphitic layers (Fe3C@NG) via a one-step solid-state thermal reaction. The optimized Fe3C@NG800-0.2 catalyst shows comparable ORR activity with the state-of-the-art Pt/C catalyst and OER activity with the benchmarking RuO2 catalyst. The oxygen electrode activity parameter ΔE (the criteria for judging the overall catalytic activity of bifunctional electrocatalysts) value for Fe3C@NG800-0.2 is 0.780 V, which surpasses those of Pt/C and RuO2 catalysts as well as those of most nonprecious metal catalysts. Significantly, excellent long-term catalytic durability holds great promise in fields of rechargeable metal-air batteries and URFCs.Keywords: graphitic layers; iron carbide; oxygen electrocatalysts; oxygen evolution reaction; oxygen reduction reaction
Co-reporter:Xiaoming Lv, Yihua Zhu, Hongliang Jiang, Xiaoling Yang, Yanyan Liu, Yunhe Su, Jianfei Huang, Yifan Yao and Chunzhong Li
Dalton Transactions 2015 vol. 44(Issue 9) pp:4148-4154
Publication Date(Web):19 Jan 2015
DOI:10.1039/C4DT03803G
The design and fabrication of efficient and inexpensive electrodes for oxygen evolution reaction (OER) is essential for energy-conversion technologies. Herein, high OER activity is achieved using hollow mesoporous NiCo2O4 nanocages synthesized via a Cu2O-templated strategy combined with coordination reaction. The NiCo2O4 nanostructures with a hollow cavity, large roughness and high porosity show only a small overpotential of ∼0.34 V at the current density of 10 mA cm−2 and a Tafel slope of 75 mV per decade, which is comparable with the performance of the best reported transition metal oxide based OER catalysts in the literature. Meanwhile, the positive impacts of the nanocage structure and the Ni incorporation on the electrocatalytic performance are also demonstrated by comparing the OER activities of NiCo2O4 nanocages with Co3O4 nanocages, NiCo2O4 nanoparticles and 20 wt% Pt/C. Moreover, the NiCo2O4 nanocages also manifest superior stability to other materials. All these merits indicate that the hollow mesoporous NiCo2O4 nanocages are promising electrocatalysts for water oxidation.
Co-reporter:Ying Zhou, Yihua Zhu, Xiaoling Yang, Jianfei Huang, Wei Chen, Xiaoming Lv, Cuiyan Li and Chunzhong Li
RSC Advances 2015 vol. 5(Issue 62) pp:50454-50461
Publication Date(Web):26 May 2015
DOI:10.1039/C5RA08243A
Heterostructured Au nanoparticle decorated Fe3O4@TiO2 composite magnetic microspheres (MSs) were synthesized by grafting Au nanoparticles onto 3-aminopropyltrimethoxysilane (APTMS) modified Fe3O4@TiO2 MSs. Significantly, by varying the reaction conditions, the as-synthesized Fe3O4@TiO2@Au MSs showed high performance in the catalytic reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of NaBH4 under visible light. In addition, the as-prepared Fe3O4@TiO2@Au MSs can clean themselves by photocatalytic degradation of organic molecules, and can be reused for several cycles with convenient magnetic separability. This approach provided a platform based on the synergy of varying components under suitable conditions to optimize the catalytic ability.
Co-reporter:Xin Jiang, Xiaoling Yang, Yihua Zhu, Hongliang Jiang, Yifan Yao, Peng Zhao and Chunzhong Li
Journal of Materials Chemistry A 2014 vol. 2(Issue 29) pp:11124-11133
Publication Date(Web):08 May 2014
DOI:10.1039/C4TA01348D
A three-dimensional (3D) foam architecture of ultrafine TiO2 nanoparticles embedded in N-doped graphene networks (denoted as UTO/NGF) is prepared via a facile hydrothermal self-assembly and a subsequent freeze-drying scheme. The obtained UTO/NGF possesses a large surface area, macro/mesoporous structure, and high-level nitrogen content (7.34%). Such a unique hierarchical architecture provides multidimensional electronic network, enlarged contact area between electrolyte and electrode, and numerous open channels for the access of the electrolyte, thus favoring diffusion kinetics for both electrons and lithium ions. Meanwhile, nitrogen doping can further improve the electrical conductivity and electrochemical activity of the obtained composite during electrochemical processes. As a consequence, the UTO/NGF exhibits high reversible capacities with remarkable cyclic retention at different current rates (165 mA h g−1 after 200 cycles at 1 C rate, 143 mA h g−1 after 200 cycles at 5 C rate) and excellent rate performance (96 mA h g−1 at 20 C) as anodes in lithium ion batteries.
Co-reporter:Yunhe Su, Yihua Zhu, Hongliang Jiang, Jianhua Shen, Xiaoling Yang, Wenjian Zou, Jianding Chen and Chunzhong Li
Nanoscale 2014 vol. 6(Issue 24) pp:15080-15089
Publication Date(Web):15 Oct 2014
DOI:10.1039/C4NR04357J
Cobalt based catalysts are promising bifunctional electrocatalysts for both oxygen reduction and oxygen evolution reactions (ORR and OER) in unitized regenerative fuel cells (URFCs) operating with alkaline electrolytes. Here we report a hybrid composite of cobalt nanoparticles embedded in nitrogen-doped carbon (Co/N-C) via a solvothermal carbonization strategy. With the synergistic effect arising from the N-doped carbon and cobalt nanoparticles in the composite, the Co/N-C hybrid catalyst exhibits highly efficient bifunctional catalytic activity and excellent stability toward both ORR and OER. The ΔE (oxygen electrode activity parameter for judging the overall electrocatalytic activity of a bifunctional electrocatalyst) value for Co/N-C is 0.859 V, which is smaller than those of Pt/C and most of the non-precious metal catalysts in previous studies. Furthermore, the Co/N-C composite also shows better bifunctional catalytic activity than its oxidative counterparts, which could be attributed to the high specific surface area and the efficient charge transfer ability of the composite, as well as the good synergistic effect between N-doped carbon and the Co nanoparticles in the Co/N-C composite.
Co-reporter:Xiaoqing Zhang, Yihua Zhu, Xiaoling Yang, Ying Zhou, Yifan Yao and Chunzhong Li
Nanoscale 2014 vol. 6(Issue 11) pp:5971-5979
Publication Date(Web):21 Mar 2014
DOI:10.1039/C4NR00975D
Herein, we demonstrate the design and fabrication of multifunctional triplex Fe3O4@TiO2@Au core–shell magnetic microspheres (MSs), which show excellent surface enhanced Raman scattering (SERS) activity with high reproducibility and stability. In addition, due to their excellent catalytic properties, the as-prepared Fe3O4@TiO2@Au magnetic MSs can clean themselves by photocatalytic degradation of target molecules adsorbed onto the substrate under irradiation with visible light, and can be re-used for several cycles with convenient magnetic separability. The influence of the size and distribution of Au nanoparticles (NPs) on the Fe3O4@TiO2 beads is investigated. The optimized samples employing Au NPs of 15 nm size and an areal density of about 2120 Au NPs on every MS show the best SERS activity and recyclable performance. The experimental results show that these magnetic MSs indicate a new route in eliminating the ‘single-use’ problem of traditional SERS substrates and exhibit their applicability as analytical tools for the detection of different molecular species.
Co-reporter:Xiaoling Yang, Hua Zhong, Yihua Zhu, Hongliang Jiang, Jianhua Shen, Jianfei Huang and Chunzhong Li
Journal of Materials Chemistry A 2014 vol. 2(Issue 24) pp:9040-9047
Publication Date(Web):26 Feb 2014
DOI:10.1039/C4TA00119B
Non-noble metal copper (Cu) nanoparticles (NPs) with controlled size and surface coverage are decorated on silicon nanowire arrays (SiNWAs) by a simple galvanic displacement reaction. Using the combined efforts of all these approaches, SiNWAs-supported Cu NPs (SiNWAs–Cu) exhibit excellent and stable activity for the catalytic reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by sodium borohydride (NaBH4) in an aqueous solution, which can be recycled for five successive cycles of the reaction with a conversion efficiency of more than 95%. This novel catalyst also shows excellent catalytic performance for the degradation of other organic dyes, such as methylene blue (MB) and rhodamine B (RhB). Additionally, we demonstrate that the catalytic activity of SiNWAs–Cu is comparable to other SiNWAs-supported noble metal NPs (i.e., Ag and Au). Furthermore, SiNWAs as powerful substrates can be reused for decorating with Cu NPs after dilute HNO3 treatment. SiNWAs–Cu is particularly attractive as a catalyst, although Cu is orders of magnitude cheaper than any noble metals, its catalytic performance is comparable to other noble metals. So SiNWAs–Cu is thus expected to have the potential as a highly efficient, cost-effective and eco-friendly reusable catalyst to replace noble metals for certain catalytic applications.
Co-reporter:Peng Zhao, Jing Zhang, Yihua Zhu, Xiaoling Yang, Xin Jiang, Yuan Yuan, Changsheng Liu and Chunzhong Li
Journal of Materials Chemistry A 2014 vol. 2(Issue 47) pp:8372-8377
Publication Date(Web):03 Oct 2014
DOI:10.1039/C4TB01445F
A highly efficient multifunctional nanoplatform for dual-modal luminescence imaging and pH-responsive drug delivery has been developed on the basis of a facile and novel strategy by covalently binding up-conversion (UC) luminescent NaYF4:Yb,Er nanoparticles with down-conversion (DC) fluorescent AgInS2–ZnS quantum dots. Due to the enriched carboxylic groups in the polymer shell of UC nanoparticles, the as-prepared nanocomposites (NCs) are water-soluble, functionalizable and able to load anti-cancer drug molecules, doxorubicin (DOX), by simple physical adsorption. The release of DOX from NCs was controlled by varying the pH, with an increased drug dissociation rate in an acidic environment, favorable for controlled drug release. Moreover, the endocytosis and the efficient drug release properties of the system were confirmed by luminescence microscopy. Hence, this approach provides a valuable method for fabricating a NC system with highly integrated functionalities for dual-modal luminescence cell imaging and targeted cancer therapy.
Co-reporter:Peng Zhao, Yuanyuan Wu, Yihua Zhu, Xiaoling Yang, Xin Jiang, Jingfan Xiao, Yuanxing Zhang and Chunzhong Li
Nanoscale 2014 vol. 6(Issue 7) pp:3804-3809
Publication Date(Web):27 Feb 2014
DOI:10.1039/C3NR06549A
Here, we report a simple and ultrasensitive upconversion fluorescent strip sensor based on NaYF4:Yb,Er nanoparticles (NPs) and the lateral flow immunochromatographic assay (LFIA). Carboxyl-modified β-NaYF4:Yb,Er NPs were successfully synthesized by a facile one-pot solvothermal approach, upon further coupling with monoclonal antibody, the resultant UCNPs-antibody conjugates probes were used in LFIA and served as signal vehicles for the fluorescent reporters. V. anguillarum was used as a model analyte to demonstrate the use of this strip sensor. The limit of the detection for the fluorescent strip was determined as 102 CFU mL−1, which is 100 times lower than those displayed by enzyme-linked immunosorbent assays, while the time needed for the detection was only 15 min. Furthermore, no cross-reaction with other eight pathogens was found, indicating the good specificity of the strip. This developed LFIA would offer the potential as a useful tool for the quantification of pathogens analysis in the future.
Co-reporter:Yunhe Su, Hongliang Jiang, Yihua Zhu, Xiaoling Yang, Jianhua Shen, Wenjian Zou, Jianding Chen and Chunzhong Li
Journal of Materials Chemistry A 2014 vol. 2(Issue 20) pp:7281-7287
Publication Date(Web):21 Feb 2014
DOI:10.1039/C4TA00029C
Graphitic N is proposed to be one of the most likely active sites for the oxygen reduction reaction (ORR) in N-doped carbon materials. However, the recent hybrid composites consisting of N-doped carbons and transition metal oxides for the ORR are predominantly pyridinic N- and pyrrolic N-doped carbon-supported cobalt or manganese oxides. Here, an enriched graphitic N-doped carbon-supported Fe3O4 nanoparticles composite was prepared via a solvothermal carbonization process. The hybrid composite exhibits a similar high catalytic activity with the 4e− reaction pathway but superior stability to Pt/C for the ORR in alkaline media. Furthermore, the composite also shows a better ORR performance than previously reported transition metal oxides-based N-doped carbon hybrid composites. The unusual high catalytic activity arises from the combination of the high surface area and the synergetic coupling effect between the enriched graphitic N-doped carbon and Fe3O4 nanoparticles.
Co-reporter:Jianfei Huang, Yihua Zhu, Hua Zhong, Xiaoling Yang, and Chunzhong Li
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 10) pp:7055
Publication Date(Web):May 6, 2014
DOI:10.1021/am501799w
A finely dispersed CuO nanoparticle electrocatalyst on a silicon nanowire (SiNW) was achieved via a designed, precursor-mediated strategy by combining metal-assisted chemical etching, electroless deposition, and thermal oxidation. The CuO assembled on silicon nanowires (CuO-SiNWs) showed a competent sensitivity of 22.27 μA/mM, a wider linear range from 0.01 to 13.18 mM, and a comparable detection limit of 1.6 μM (3S/N) for nonenzymatic H2O2 detection. The archetype sensor also demonstrated eligible selectivity against common interfering species. By the introduction of the SiNW carrier, which led to mitigated conglomeration of the electrocatalyst and a favorable microstructure of the electrocatalyst–carrier system, improved signal-concentration linearity and higher electrocatalyst utilization efficiency were obtained with CuO-SiNWs. These results demonstrated the feasibility of the synthetic strategy and the potential of the nanocomposite as a promising candidate for H2O2 sensing.Keywords: cupric oxide; hydrogen peroxide; mitigated conglomeration; nonenzymatic sensor; precursor-mediated; silicon nanowire;
Co-reporter:Xiaoling Yang, Wenjian Zou, Yunhe Su, Yihua Zhu, Hongliang Jiang, Jianhua Shen, Chunzhong Li
Journal of Power Sources 2014 Volume 266() pp:36-42
Publication Date(Web):15 November 2014
DOI:10.1016/j.jpowsour.2014.04.126
•Activated N-doped carbon nanofibers have been synthesized via a facile route.•The stack of ANCNFs forms a 3D carbon nanofiber framework with hierarchical pores.•The ANCNFs show better mass transfer and improved performance for ORR.•The ANCNFs exhibit comparable MFC performance to the commercial Pt/C catalyst.Oxygen reduction reaction (ORR) in microbial fuel cell (MFC) was evaluated by using chemical activated nitrogen-doped carbon nanofibers (ANCNFs) as cathode catalyst. ANCNFs are synthesized through modified oxidative template assembly route and then activated by KOH reagent. The as-prepared ANCNFs formed three-dimensional carbonfiber framework with large specific surface area and hierarchical tetramodal pore size distribution spanning the micro-, meso- and macro pore range, centered at 0.48, 4.0, 18 and 70 nm. Compared with unactivated nitrogen-doped carbon nanofibers (NCNFs), ANCNFs exhibited a more positive onset potential, higher current density as well as higher electron transfer number in neutral environment, highlighting the importance of chemical activation process for improving the ORR performance. MFCs equipped with ANCNFs catalyst exhibited a high power output of 1377 ± 46 mW m−2, which is about 1.5 times the output of NCNFs cathode (921 ± 29 mW m−2), and as high as nearly 4 times of plain cathode (341 ± 9 mW m−2).
Co-reporter:Yunhe Su, Hongliang Jiang, Yihua Zhu, Wenjian Zou, Xiaoling Yang, Jianding Chen, Chunzhong Li
Journal of Power Sources 2014 Volume 265() pp:246-253
Publication Date(Web):1 November 2014
DOI:10.1016/j.jpowsour.2014.04.140
•Hierarchical porous iron and nitrogen co-doped carbons have been successfully prepared.•The synthesized HP–Fe–N–Cs show efficient ORR catalytic activities in neutral media.•The HP–Fe–N–C-900 shows comparable MFCs performance to the commercial Pt/C catalyst.Hierarchical porous iron and nitrogen co-doped carbons (HP–Fe–N–Cs) as efficient cathode catalysts for oxygen reduction reaction (ORR) in neutral media are reported. The HP–Fe–N–Cs are prepared by using polypyrrole as nitrogen source and poly(vinyl alcohol) (PVA) hydrogel-based composites as in-situ templates. In studying the effect of the iron and the hierarchical porous structure on the nitrogen-doped carbon support for ORR, we find that HP–Fe–N–Cs show more positive onset potential, higher cathodic current density, and higher electron transfer number for the ORR in neutral media than iron-free hierarchical porous nitrogen-doped carbon (HP–N–C) and non-hierarchical porous iron and nitrogen co-doped carbon (Fe–N–C), highlighting the importance of the iron and the hierarchical porous structure for improving the ORR performance. Furthermore, HP–Fe–N–Cs show better durability than the commercial Pt/C catalysts in neutral media, and the microbial fuel cells (MFCs) equipped with HP–Fe–N–Cs catalysts on cathodes exhibit comparable power outputs with those of MFCs with commercial Pt/C cathode catalysts.
Co-reporter:Peng Zhao, Yihua Zhu, Xiaoling Yang, Jianhua Shen, Xin Jiang, Jie Zong and Chunzhong Li
Dalton Transactions 2014 vol. 43(Issue 2) pp:451-457
Publication Date(Web):06 Sep 2013
DOI:10.1039/C3DT52066H
We report on a novel drug carrier which is based on the combination of magnetic and upconversion (UC) emission of Fe3O4@SiO2/NaYF4:Yb, Er (MSU) hybrids modified with MnO2 nanosheets (MSU/MnO2). The MSU hybrids were fabricated by covalently linking amino-modified Fe3O4@SiO2 particles with carboxyl-functionalized NaYF4:Yb, Er particles. The Fe3O4 core and the NaYF4:Yb, Er shell functioned successfully for magnetic targeting and fluorescence imaging, respectively. MnO2 nanosheets served as drug carriers and UC luminescence quenchers. The drug can be released by introducing glutathione (GSH) which reduces MnO2 to Mn2+, and at the same time, UC luminescence can be turned on. These results clearly show that these MSU/MnO2 nanocomposites are promising platforms which can be applied to construct a smart drug delivery system with magnetic targeting and GSH-stimulation, as well as tracking by UC luminescence.
Co-reporter:Xiaoming Lv, Yihua Zhu, Hongliang Jiang, Hua Zhong, Xiaoling Yang and Chunzhong Li
Dalton Transactions 2014 vol. 43(Issue 40) pp:15111-15118
Publication Date(Web):13 Aug 2014
DOI:10.1039/C4DT02245A
A novel and facile strategy has been successfully developed to synthesize uniform gold@titanium dioxide octahedral nanocages (Au@TiO2), which have a well-defined double-shelled structure with Au as the internal shell and TiO2 as the external shell. The unique Au@TiO2 double-shelled octahedral nanocages were elaborately fabricated by a Cu2O-templated strategy combining with spatially confined galvanic replacement. The formation process of these delicate hierarchical octahedral architectures is discussed in detail. The catalytic performance of the Au@TiO2 double-shelled octahedral nanocages was investigated using the reduction of 4-nitrophenol as a model reaction. The mesoporous structure of both the Au and TiO2 shells provides direct access for the reactant molecules to diffuse and subsequently interact with the Au shell. This novel catalyst shows excellent and stable activity for the catalytic reduction of 4-nitrophenol, which can be recycled for ten successive cycles of the reaction with a conversion efficiency of more than 90%. The superior catalytic activity attributes to mesoporous double shells, enhanced synergistic effects between the Au and TiO2 shells and the unique properties of the octahedral structure. More importantly, the as-obtained Au@TiO2 double-shelled octahedral nanocages also show potential applications in solar cells, organocatalysis and water splitting.
Co-reporter:Siwen Wang, Xiaoling Yang, Yihua Zhu, Yunhe Su and Chunzhong Li
RSC Advances 2014 vol. 4(Issue 45) pp:23790-23796
Publication Date(Web):07 May 2014
DOI:10.1039/C4RA02488E
We report a solar-assisted microbial fuel cell (solar MFC) that can produce electricity through coupling a microbial anode with flower-like CuInS2 (CIS) as the photocathode. Scanning electron microscopy images displayed a hierarchical structure of CIS, which would be beneficial to facilitate electron transfer in MFC. The electrochemical and photo-responsive activity of CIS was investigated by cyclic voltammetry, linear sweep voltammetry (LSV) and photocurrent tests. We propose a hypothesized mechanism of MFC operation that light-responsive CIS generated electron–hole pairs and triggered bioanodes for electricity generation. LSV curves and photocurrent data displayed the flower-like CIS and showed enhanced photocurrent generation under visible light irradiation. Based on the improved photoelectrochemical properties, the solar MFC achieved a maximum power density of 0.108 mW cm−2 and a current density of 0.62 mA cm−2. CIS as a photocathode presents a comparable power density to Pt/C in MFC.
Co-reporter:Jianmei Zhang, Yunhe Su, Yihua Zhu, Jieping Yun and Xiaoling Yang
New Journal of Chemistry 2014 vol. 38(Issue 6) pp:2300-2304
Publication Date(Web):28 Jan 2014
DOI:10.1039/C3NJ01386C
The direct generation of electrical energy from sunlight and a biomass solution with use of a photoelectrochemical biofuel cell (PEBFC) was investigated. The PEBFC was constructed from dendrimer-encapsulated CdSe nanoparticles-sensitized titanium dioxide (TiO2/CdSe-DENs) as the photoanode, along with dendrimer-encapsulated Pt nanoparticles (Pt-DENs) as the cathode and the proton exchange membrane (PEM). The morphology of the TiO2/CdSe-DENs and Pt-DENs on carbon paper was characterized by scanning electron microscopy (SEM), and the effects of the TiO2/CdSe-DENs deposited on the carbon paper and the glucose concentration in the electrolyte on the photoelectrochemical responses were studied through photoelectrochemical measurements. Based on the optimal conditions, an open circuit voltage of 0.5 V and a maximum power density of 40 μW cm−2 could be obtained under light irradiation (λ > 400 nm) from the CdSe-DENs sensitized PEBFCs, indicating that the CdSe-DENs are efficient photosensitizers for PEBFCs.
Co-reporter:Babao Lin, Xiuzhong Yao, Yihua Zhu, Jianhua Shen, Xiaoling Yang and Chunzhong Li
RSC Advances 2014 vol. 4(Issue 40) pp:20641-20648
Publication Date(Web):29 Apr 2014
DOI:10.1039/C4RA02424A
A new magnetic resonance (MR)/optical nanoparticle based on silica-coated CuInS2/ZnS nanoparticles with covalent attachment of a Gd3+ complex for cancer cell imaging is reported. We introduce silica to interdigitate with hydrophobic, protective agents on the surface of CuInS2/ZnS nanoparticles that allows phase transfer of hydrophobic nanoparticles from the organic into the aqueous phase. Carbodiimide chemistry is used to covalently couple the Gd3+-complex on the surface of silica-coated CuInS2/ZnS nanoparticles for magnetic resonance and fluorescence imaging of cancer cells. The longitudinal relaxivity value is 8.45 mM−1 s−1 for the dual-modality nanoparticles on the 3.0 T scanner, suggesting the possibility of using the nanoparticles as a T1 contrast agent. The dual-modality nanoparticles exhibit negligible cytotoxicity with >80% cell viability in human pancreatic cancer cell line BXPC-3 cells after 24 h. The nanoparticles with both optical and MR imaging in the aqueous solution were applied to cells in culture. These results show that the quantum yield and gadolinium concentration in the nanoparticles are sufficient to produce contrast for both modalities at relatively low concentrations of nanoparticles.
Co-reporter:Jie Zong, Xiaoling Yang, Adrian Trinchi, Simon Hardin, Ivan Cole, Yihua Zhu, Chunzhong Li, Tim Muster, Gang Wei
Biosensors and Bioelectronics 2014 Volume 51() pp:330-335
Publication Date(Web):15 January 2014
DOI:10.1016/j.bios.2013.07.042
•Carbon dots (CDs) were applied in the detection of Cu2+ and l-cysteine.•Cu2+ quenched the fluorescence of CDs through the charge transfer process.•l-cysteine sheltered the quenching as it can remove Cu2+ from the surface of CDs.•The fluorescence quenching and recovery demonstrated the “off–on” detection process.•This system has high sensitivity, selectivity, and low detection limit.Copper ion (Cu2+) and l-cysteine (l-Cys) detection is critically important since an abnormal level of Cu2+ or l-Cys is an indicator for many diseases. In this paper, we demonstrate an “off–on” approach for highly sensitive and selective detection of Cu2+ and l-Cys using carbon dots (CDs) as fluorescent probes. CDs were prepared by using mesoporous silica (MS) spheres as nanoreactors. The binding ability of CDs towards metal ions was examined by comparing the fluorescence intensities of CDs before and after the addition of the metal ions. The addition of Cu2+ cations leads to their absorption on the surface of CDs and the significant fluorescence quench of CDs (turn-off). The resulting in CDs-Cu2+ system was found to be sensitive to l-Cys. The addition of l-Cys not only serves to shelter the CDs effectively from being quenched, but also to reverse the quenching and restore the fluorescence (turn-on) due to its ability to remove Cu2+ from the surface of CDs. This method is facile, rapid, low cost, and environment-friendly. A detection limit as low as 2.3×10−8 M for Cu2+ and 3.4×10−10 M for l-Cys is obtained, which is promising for biological applications.
Co-reporter:Dr. Hongliang Jiang; Yihua Zhu;Dr. Qian Feng;Dr. Yunhe Su; Xiaoling Yang ; Chunzhong Li
Chemistry - A European Journal 2014 Volume 20( Issue 11) pp:3106-3112
Publication Date(Web):
DOI:10.1002/chem.201304561
Abstract
Despite tremendous progress in developing doped carbocatalysts for the oxygen reduction reaction (ORR), the ORR activity of current metal-free carbocatalysts is still inferior to that of conventional Pt/C catalysts, especially in acidic media and neutral solution. Moreover, it also remains a challenge to develop an effective and scalable method for the synthesis of metal-free carbocatalysts. Herein, we have developed nitrogen and phosphorus dual-doped hierarchical porous carbon foams (HP-NPCs) as efficient metal-free electrocatalysts for ORR. The HP-NPCs were prepared for the first time by copyrolyzing nitrogen- and phosphorus-containing precursors and poly(vinyl alcohol)/polystyrene (PVA/PS) hydrogel composites as in situ templates. Remarkably, the resulting HP-NPCs possess controllable nitrogen and phosphorus content, high surface area, and a hierarchical interconnected macro-/mesoporous structure. In studying the effects of the HP-NPCs on the ORR, we found that the as-prepared HP-NPC materials exhibited not only excellent catalytic activity for ORR in basic, neutral, and acidic media, but also much better tolerance for methanol oxidation and much higher stability than the commercial, state-of-the-art Pt/C catalysts. Because of all these outstanding features, it is expected that the HP-NPC material will be a very suitable catalyst for next-generation fuel cells and lithium–air batteries. In addition, the novel synthetic method described here might be extended to the preparation of many other kinds of hierarchical porous carbon materials or porous carbon that contains metal oxide for wide applications including energy storage, catalysis, and electrocatalysis.
Co-reporter:Hongliang Jiang, Yunhe Su, Yihua Zhu, Jianhua Shen, Xiaoling Yang, Qian Feng and Chunzhong Li
Journal of Materials Chemistry A 2013 vol. 1(Issue 39) pp:12074-12081
Publication Date(Web):08 Aug 2013
DOI:10.1039/C3TA12493B
Three-dimensional (3D) hierarchical porous Co-containing N-doped carbon materials (HP-Co-CNs) have been successfully prepared for the first time by using cyanamide as a nitrogen source and poly(vinyl alcohol) (PVA) hydrogel-based composites as in situ templates. Remarkably, the resulting HP-Co-CNs possess controllable nitrogen content, high surface area, hierarchical interconnected macro-/mesoporous structure, and a certain amount of Co-Nx moieties which could act as active sites in the oxygen reduction reaction (ORR). In studying the application of HP-Co-CNs for the ORR, the HP-Co-CNs showed excellent electrocatalytic performance for a four-electron ORR, and longer-term stability and higher methanol tolerance then the commercial Pt/C electrocatalyst in alkaline medium, highlighting the importance of macropores for diffusion and a sufficient amount of active sites related to high specific surface area for improving the ORR performance.
Co-reporter:Xiaoling Yang, Kaicai Fan, Yihua Zhu, Jianhua Shen, Xin Jiang, Peng Zhao, Shaorong Luan, and Chunzhong Li
ACS Applied Materials & Interfaces 2013 Volume 5(Issue 3) pp:997
Publication Date(Web):January 15, 2013
DOI:10.1021/am302685t
A facile strategy to synthesize the novel composite paper of graphene nanosheets (GNS) coated Co3O4 fibers is reported as an advanced anode material for high-performance lithium-ion batteries (LIBs). The GNS were able to deposit onto Co3O4 fibers and form the coating via electrostatic interactions. The unique hybrid paper is evaluated as an anode electrode for LIBs, and it exhibits a very large reversible capacity (∼840 mA h g–1 after 40 cycles), excellent cyclic stability and good rate capacity. The substantially excellent electrochemical performance of the graphene/Co3O4 composite paper is the result from its unique features. Notably, the flexible structure of graphenic scaffold and the strong interaction between graphene and Co3O4 fibers are beneficial for providing excellent electronic conductivity, short transportation length for lithium ions, and elastomeric space to accommodate volume varies upon Li+ insertion/extraction.Keywords: anode; Co3O4 fiber; graphene paper; lithium-ion batteries;
Co-reporter:Xin Jiang, Xiaoling Yang, Yihua Zhu, Jianhua Shen, Kaicai Fan, Chunzhong Li
Journal of Power Sources 2013 Volume 237() pp:178-186
Publication Date(Web):1 September 2013
DOI:10.1016/j.jpowsour.2013.03.048
•3D aerogels consisted of graphene-supported SnS2 nanoplates are prepared by hydrothermal assembly and freeze-drying process.•As-prepared aerogels show interconnected networks, large surface area and large numbers of macropores.•As-prepared aerogels exhibit high-rate capability and cycling stability when used as an anode.Three-dimensional (3D) SnS2/graphene aerogels (SnS2/G-As) have been successfully fabricated via an in situ macroscopy self-assembly of graphene sheets which embedded SnS2 nanoplates in a hydrothermal process, and then freeze-drying to maintain the 3D monolithic architectures. The graphene sheets in high concentration will be easily restacked into 3D architectures driven by combined hydrophobic and π–π stacking interactions during hydrothermal reduction process, meanwhile SnS2 facilitate stabilizing such novel graphene networks. The obtained SnS2/G-As show interconnected graphene networks, large surface area and large numbers of macropores. The novel 3D architectures in SnS2/G-As, which can provide rich sites for absorbing lithium ions and facilitate electrolyte contact as well as ionic diffusion, combined with the synergistic effect between the layered SnS2 and the graphene make SnS2/G-As achieve high reversible capacity (656 mA h g−1 with a coulombic efficiency of over 95% after 30 cycles) and excellent rate capability (240 mA h g−1 at the rate of 1000 mA g−1) when used as an anode in rechargeable LIBs.
Co-reporter:Xiaoling Yang, Hua Zhong, Yihua Zhu, Jianhua Shen and Chunzhong Li
Dalton Transactions 2013 vol. 42(Issue 39) pp:14324-14330
Publication Date(Web):29 Jul 2013
DOI:10.1039/C3DT51686E
Metallic nanoparticle (NP) decorated silicon nanowire (SiNW) heterostructures show significant promise in enhanced optical and opto-electrical properties due to the coupling of surface plasmon to nanowires. Here, recyclable Au-decorated silicon nanowire arrays (Au-SiNWAs) as surface-enhanced Raman scattering (SERS) substrates were successfully fabricated by a simple galvanic displacement reaction. The influence of different average size and aggregation level of Au NPs on SERS activity was explored. The SERS activity of the substrates strongly depends on the average size and aggregation level of Au NPs on the surface of the SiNWs, and the most optimal size and separation of AuNPs on the SiNWs can be achieved by controlling the reaction time. The optimized Au-SiNWA substrate exhibits ultrahigh sensitivity with an enhancement factor of 109, and is able to detect the analyte molecule at a concentration as low as 10−11 M. More importantly, the SERS substrate is recyclable, as enabled by a self-cleaning function due to UV light photocatalytic degradation of the analyte molecules. The high sensitivity and recyclability of the Au-SiNWA SERS substrate is demonstrated by the detection of a model molecule rhodamine B (RhB). Our studies show that the unique Au-SiNWA SERS substrates have significant potential to put SERS into wider application.
Co-reporter:Xin Jiang, Xiaoling Yang, Yihua Zhu, Kaicai Fan, Peng Zhao and Chunzhong Li
New Journal of Chemistry 2013 vol. 37(Issue 11) pp:3671-3678
Publication Date(Web):22 Aug 2013
DOI:10.1039/C3NJ00797A
Well-designed graphene–TiO2–SnO2 ternary nanocomposites, in which the nanometer-sized TiO2 and SnO2 nanoparticles formed in situ uniformly anchored on the surface of reduced graphene oxide sheets, are synthesized by a solvothermal method combined with a hydrothermal two-step method. Although the contribution of anatase TiO2 to the total specific capacity of obtained ternary nanocomposites is limited by its low theoretical specific capacity, the small amount of TiO2 nanoparticles can form more clearance space to accommodate the electrode volume change and act as stable barriers to effectively prevent the agglomeration of SnO2 nanoparticles during the charge–discharge process. Additionally, the good combination and synergistic effects among uniformly distributed TiO2 nanoparticles, high-capacity SnO2 and conductive graphene sheets work together to tackle the aggregation of nanoparticles while keeping the overall electrode sturdy and highly active in the lithium storage process. Therefore, when evaluated as anode materials in lithium-ion batteries, the as-synthesized ternary nanocomposites deliver improved cycling performance (537 mA h g−1 at 50 mA g−1 accompanied by coulombic efficiency of 97% after 50 cycles) and good reversible capacities (250 mA h g−1 even at the current density 1000 mA g−1) in the voltage range of 0.01 to 3.00 V. By limiting the voltage window in the range of 0.01 to 1.00 V, which is the optimum voltage range for the alloying–dealloying reaction between lithium and Sn, ternary nanocomposites exhibit a more stable cycling performance (more than 70% of initial reversible capacity being retained).
Co-reporter:Yunhe Su, Yihua Zhu, Xiaoling Yang, Jianhua Shen, Jindan Lu, Xiaoyan Zhang, Jianding Chen, and Chunzhong Li
Industrial & Engineering Chemistry Research 2013 Volume 52(Issue 18) pp:6076
Publication Date(Web):April 16, 2013
DOI:10.1021/ie4003766
A nanocomposite of cobaltosic oxide and nitrogen-doped graphene (Co3O4/N-G) was prepared by the facile hydrothermal method. Morphology characterizations show that the Co3O4 nanoparticles with crystalline spinel structure are uniformly dispersed on the nitrogen-doped graphene nanosheets, and the graphene weight fraction in Co3O4/N-G composite is estimated to be ∼20%. Meanwhile, electrochemical measurements reveal that the as-prepared Co3O4/N-G nanocomposite exhibits a high catalytic activity and long-term stability in neutral electrolyte. Moreover, the use of Co3O4/N-G as cathode catalyst for oxygen reduction in microbial fuel cells (MFCs) to produce electricity was also investigated. The obtained maximum power density was 1340 ± 10 mW m–2, which was as high as almost four times that of the plain cathode (340 ± 10 mW m–2), and only slightly lower than that of a commercial Pt/C catalyst (1470 ± 10 mW m–2). All the results prove that a Co3O4/N-G hybrid can be a good alternative to platinum catalysts for practical MFC applications.
Co-reporter:Hongliang Jiang, Xiaoling Yang, Cheng Chen, Yihua Zhu and Chunzhong Li
New Journal of Chemistry 2013 vol. 37(Issue 5) pp:1578-1583
Publication Date(Web):04 Mar 2013
DOI:10.1039/C3NJ00024A
A facile and controllable strategy for preparing three-dimensionally quasi-ordered macroporous (3DOM) TiO2 has been developed through in situ hydrolysis on poly(vinyl alcohol) (PVA) gelated crystalline colloidal array (GCCA) photonic crystal films. The presence of PVA hydrogel in the PVA GCCA results in a non-close-packed structure and an increase in the hydrophilic character of the template, which contribute to a more uniform wetting of the template during the infiltration process. The resulting 3DOM TiO2 as an anode material for lithium-ion batteries (LIBs) exhibits a high rate capability and excellent cycle performance. The method presented in this paper is versatile and can be expanded for preparing various quasi-order macroporous materials.
Co-reporter:Babao Lin, Xiuzhong Yao, Yihua Zhu, Jianhua Shen, Xiaoling Yang, Hongliang Jiang and Xiaoqing Zhang
New Journal of Chemistry 2013 vol. 37(Issue 10) pp:3076-3083
Publication Date(Web):15 Jul 2013
DOI:10.1039/C3NJ00407D
We synthesized cadmium-free CuInS2–Zn1−xMnxS core–shell quantum dots (QDs) for use in dual-mode optical and magnetic resonance (MR) imaging techniques. Manganese content was in the rang of 0.2–2.3% and varies with the amount of Mn2+ content in the reaction. These materials presented a high quantum yield (QY) of 52% in organic solvent. The CuInS2–Zn1−xMnxS nanoparticles were subsequently transferred to the aqueous phase by the aid of cetyltrimethylammonium bromide (CTAB), and the QY values in water reached 18%. Relaxivity measurements showed that these materials had a T1 relaxivity (r1) of 7.2 mM−1 s−1 on the 3.0 T scanner, suggesting the possibility of using the nanoparticles as a T1 contrast agent. The nanomaterials for both optical and MR imaging in aqueous solution were applied to cells in culture. These results showed that the QY and manganese concentration in the nanoparticles was sufficient to produce contrast for both modalities at relatively low concentrations of nanoparticles.
Co-reporter:Haopeng Li, Yihua Zhu, Huimin Cao, Xiaoling Yang, Chunzhong Li
Materials Research Bulletin 2013 48(2) pp: 232-237
Publication Date(Web):
DOI:10.1016/j.materresbull.2012.10.052
Co-reporter:Jianhua Shen, Yihua Zhu, Xiaoling Yang, Jie Zong, and Chunzhong Li
Langmuir 2013 Volume 29(Issue 2) pp:690-695
Publication Date(Web):December 3, 2012
DOI:10.1021/la304048v
Noble metallic nanostructures exhibit a phenomenon known as surface-enhanced Raman scattering (SERS) in which the Raman scattering cross sections are dramatically enhanced for the molecules adsorbed thereon. Due to their wide accessible potential range in aqueous solutions and the high biocompatibility, Au supports are preferred for spectro-electrochemical investigations. However, the optical range in SERS spectroscopy is restricted to excitation lines above 600 nm, which is shorter than the Ag supports. In addition, these SERS-activity materials are not easy to separate and reused. Herein, the present article reports the novel multifunctional Fe3O4@Ag/SiO2/Au core–shell microspheres that display long-range plasmon transfer of Ag to Au leading to enhanced Raman scattering. The well-designed microspheres have high magnetization and uniform sphere size. As a result, Fe3O4@Ag/SiO2/Au microspheres have the best enhancement effect in the Raman active research by using Rhodamine-b (RdB) as a probe molecule. The enhancement factor is estimated to be 2.2 × 104 for RdB from the long-range plasmon transfer of Ag to Au, corresponding to an attenuation of the enhancement by a factor of only 0.672 × 104 compared to RdB adsorbed directly on the Fe3O4@Ag microspheres. RdB can be detected down to 10–9 M even without the resonance SERS effect. The unique nanostructure makes the microspheres novel stable and a high-enhancement effect for Raman detection.
Co-reporter:Xiaoling Yang, Liming Peng, Jie Zong, Yihua Zhu
Particuology 2013 Volume 11(Issue 3) pp:334-339
Publication Date(Web):June 2013
DOI:10.1016/j.partic.2012.09.008
Two types of photoluminescent carbon dots (CDs)-embedded polyelectrolyte (PE) microcapsules were successfully prepared via the layer-by-layer (LbL) assembly approach on sacrificial templates. For the first type, the PE microcapsules with CDs embedded in the cavity were produced from assembly of five pairs of poly(sodium 4-styrensulfonate) (PSS) and poly(allylamine hydrochloride) (PAH) on CDs-pre-loaded meso-porous silica. For the second type, the PE microcapsules with CDs embedded in the wall were made of CDs and PAH, which were derived from SiO2 particles as templates. Microscope images confirmed the introduction of CDs into the two CDs-embedded microcapsules. These two microcapsules also retained the optical properties of free CDs. Photoluminescence spectra revealed that the two types of microcapsules had excitation-dependent photoluminescence behavior. When the excitation wavelength changed from 280 to 340 nm, photoluminescence emission peak of the PE microcapsules with CDs embedded in the cavity shifts from 369 to 377 nm, while for microcapsules with CDs embedded in the wall, emission peak shifts from 367 to 390 nm. Due to low toxicity, good hydrophilicity and photoluminescence properties of CDs, these two kinds of photo-luminescent microcapsules have competitive potential for application in carriers for imaging, drug delivery and biosensors.Graphical abstract.Highlights► Carbon dots-embedded polyelectrolyte microcapsules were prepared via layer-be-layer assembly. ► CDs-embedded microcapsules exhibited excitation-dependent photoluminescence behavior. ► CDs-embedded microcapsules can be used as bio-friendly carriers for drug delivery.
Co-reporter:Xiaoling Yang, Kaicai Fan, Yihua Zhu, Jianhua Shen, Xin Jiang, Peng Zhao and Chunzhong Li
Journal of Materials Chemistry A 2012 vol. 22(Issue 33) pp:17278-17283
Publication Date(Web):22 Jun 2012
DOI:10.1039/C2JM32571C
Graphene-encapsulated mesoporous Co3O4 microspheres have been successfully fabricated through a facile self-assembly approach. Driven by the mutual electrostatic interactions, the mesoporous Co3O4 microspheres prepared by a nanocasting method are fully wrapped by graphene shells. We performed the evaluation as anode materials for Li-ion batteries: the composites exhibit a first discharge capacity of 1533 mA h g−1 and rapidly stabilize while remaining at a reversible capacity up to 820 mA h g−1 during all the discharge–charge cycles at a current of 100 mA g−1. The substantially improved electrochemical performance of the Co3O4–graphene composites were ascribed to the synergistic effects between the conductive graphene shells and mesoporous Co3O4 microspheres. Notably, the graphene shells not only act as buffers to accommodate the volume variation of Co3O4 but also serve as the reliable conductive channels of the electrode. In addition, the mesostructure of the mesoporous Co3O4 microspheres provides extra space for the storage of Li+ and significantly reduces paths for both Li+ ion and electron diffusion.
Co-reporter:Jianhua Shen, Yihua Zhu, Xiaoling Yang and Chunzhong Li
Journal of Materials Chemistry A 2012 vol. 22(Issue 26) pp:13341-13347
Publication Date(Web):16 May 2012
DOI:10.1039/C2JM31998E
We have demonstrated a sandwich-structured Fe3O4/SiO2/Au/TiO2 photocatalyst, which shows magnetic separability, selective absorption and photocatalysis activity, and high efficiency, in catalyzing the decomposition of organic compounds under illumination of visible-light and simulated sunlight. The structural design of the photocatalyst takes advantage of the dense, homogeneous structure and the AuNPs content (ca. 4 nm, 1.63 wt%), which is prepared by a simple method. It possesses high efficiency visible-light photocatalytic activity due to the stable from nonmetal-doping and the plasmonic metal decoration, which enhances light harvesting and charge separation, and the small grain size of the anatase nanocrystals, which reduces the exciton recombination rate. More importantly, the catalyst is synthesized by a combination of plasmonic metal decoration of TiO2 nanocrystals with exposed {001} facets, and the selective adsorption and photocatalytic decomposition of azo dyes is accomplished by design of the surface chemistry. Additionally, these sandwich-structured photocatalysts can be applied to other catalytic system such as dye decoloration, water decomposition, hydrogen generation, and so on.
Co-reporter:Jianhua Shen, Yihua Zhu, Kangfu Zhou, Xiaoling Yang and Chunzhong Li
Journal of Materials Chemistry A 2012 vol. 22(Issue 2) pp:545-550
Publication Date(Web):02 Nov 2011
DOI:10.1039/C1JM13216D
Due to the fast electron transportation and good biocompatibility, the use of graphene in biosensors is becoming more and more appealing. But a key challenge is how to obtain well-organized 2D or 3D graphene structures to build larger objects, and the development of methods for controlling the organization of functional objects on a nanometre scale to build larger objects is of fundamental and technological interest. To overcome this problem, we demonstrate a novel strategy for the fabrication of a reduced graphene oxide-encapsulated multifunctional magnetic composite microspheres (rGOE-Ms)-based anisotropic conductive film (ACF). The well-designed rGOE-Ms possess both magnetization and good electron transport properties. Magnetic properties can be detected by their movement in the gel film under an external magnet. Most interestingly, the prepared gel film has displayed the existence of rGOE-Ms alignment and anisotropy in the ACF, and the electrical resistivity of the vertical ACF was almost fifteen times higher than the horizontal. Therefore, the ACF can be extended to various advanced applications, such as chemical/biosensors, nanoelectronics, and so on.
Co-reporter:Jianhua Shen, Yihua Zhu, Xiaoling Yang and Chunzhong Li
Chemical Communications 2012 vol. 48(Issue 31) pp:3686-3699
Publication Date(Web):21 Feb 2012
DOI:10.1039/C2CC00110A
Similar to the popular older cousins, luminescent carbon dots (C-dots), graphene quantum dots or graphene quantum discs (GQDs) have generated enormous excitement because of their superiority in chemical inertness, biocompatibility and low toxicity. Besides, GQDs, consisting of a single atomic layer of nano-sized graphite, have the excellent performances of graphene, such as high surface area, large diameter and better surface grafting using π–π conjugation and surface groups. Because of the structure of graphene, GQDs have some other special physical properties. Therefore, studies on GQDs in aspects of chemistry, physical, materials, biology and interdisciplinary science have been in full flow in the past decade. In this Feature Article, recent developments in preparation of GQDs are discussed, focusing on the main two approaches (top-down and bottom-down). Emphasis is given to their future and potential development in bioimaging, electrochemical biosensors and catalysis, and specifically in photovoltaic devices that can solve increasingly serious energy problems.
Co-reporter:Huimin Cao, Yihua Zhu, Xiaoling Yang and Chunzhong Li
RSC Advances 2012 vol. 2(Issue 10) pp:4055-4058
Publication Date(Web):02 Mar 2012
DOI:10.1039/C2RA00003B
The electrospinning method combined with a solvothermal technique is employed to prepare TiO2 fibers wrapped with zincblende CuInS2. The as prepared composite fibers showed a great absorption in the whole visible region, and the photocurrent responses of the composite fibers under visible light illumination were greatly enhanced.
Co-reporter:Peng Zhao, Yihua Zhu, Xiaoling Yang, Kaicai Fan, Jianhua Shen and Chunzhong Li
RSC Advances 2012 vol. 2(Issue 28) pp:10592-10597
Publication Date(Web):07 Sep 2012
DOI:10.1039/C2RA21345A
Lanthanide-doped upconversion (UC) nanocrystals display the property of emitting visible light following photoexcitation with near-infrared laser light, which has attracted much interest because of its great potential in biological fields. Recently, the coupling of UC nanocrystals with metal nanoparticles (NPs) has been developed as a valuable strategy to enhance their luminescence. Herein, we present a facile method to fabricate mesostructured Y2O3:Er UC microspheres using mesoporous silica spheres as a hard template, and then integrate Y2O3:Er UC microspheres with Au NPs for constructing Y2O3:Er@Au hybrid composites, in which a multilayer polyelectrolyte serves as spacer. We further demonstrate the multicolour UC emissions are enhanced after adsorbing Au NPs and this enhancement can be at least partly attributed to surface plasmon-coupled emission, which can increase the radiative decay rate and emission efficiency. It is anticipated that these hybrid nanostructures may provide a platform for widely exploring applications in bioimaging, bioassays and detection.
Co-reporter:Cuiyan Li, Yihua Zhu, Xiaoqing Zhang, Xiaoling Yang and Chunzhong Li
RSC Advances 2012 vol. 2(Issue 5) pp:1765-1768
Publication Date(Web):13 Jan 2012
DOI:10.1039/C2RA01032A
Metal-enhanced fluorescence carbon dots adsorbed Ag@SiO2 composite nanoparticles, where the silica-shell is used to control the distance between silver-core and fluorescent carbon dots (CDs). A more than four-fold increase of fluorescence intensity of CDs was obtained, besides, a largely enhanced upconversion property was also observed.
Co-reporter:Jianhua Shen, Yihua Zhu, Xiaoling Yang, Jie Zong, Jianmei Zhang and Chunzhong Li
New Journal of Chemistry 2012 vol. 36(Issue 1) pp:97-101
Publication Date(Web):25 Oct 2011
DOI:10.1039/C1NJ20658C
A novel and simple approach for preparing graphene quantum dots surface-passivated by polyethylene glycol (GQDs-PEG) has been developed by a one-pot hydrothermal reaction, using small graphene oxide (GO) sheets and polyethylene glycol (PEG) as starting materials. The prepared GQDs-PEG show excellent luminescence properties, the PL quantum yield of the GQDs-PEG with 360 nm emission was about 28.0%, which was two times higher than the pure GQDs. Interestingly, the GQDs-PEG possess the upconversion photoluminescence (UCPL) properties. Blue PL was clearly shown both under the ultraviolet and 808 nm laser in the fluorescent microscopy images. So the GQDs-PEG may provide a new type of fluorescence and upconversion material for applications in bioscience and energy technology. Especially, the GQDs-PEG showed higher photocurrent generation capability. And their photoelectrode generated an obvious and stable photocurrent under a 808 nm near-infrared (NIR) laser. Due to the low cost and simple method, GQDs-PEG thus provide a cost-effective dopant material for solar energy conversion.
Co-reporter:Hongliang Jiang, Yihua Zhu, Cheng Chen, Jianhua Shen, Hua Bao, Liming Peng, Xiaoling Yang and Chunzhong Li
New Journal of Chemistry 2012 vol. 36(Issue 4) pp:1051-1056
Publication Date(Web):15 Feb 2012
DOI:10.1039/C2NJ20989F
A facile strategy for the preparation of poly(vinyl alcohol) (PVA)/poly(acrylic acid) (PAA) photonic crystal materials with pH and metal cation responses is presented. A solvent-assisted freeze–thaw method is used to form a physically cross-linked PVA gelated crystalline colloidal array (GCCA) photonic crystal. The PVA hydrogel-based photonic crystal sensors were prepared by the introduction of environmentally sensitive components responding to pH and cations into the GCCA system. The photonic crystal pH sensor shows good durability, a large stopband shift, and good adjustability. Further functionalization of 8-hydroxyquinoline makes the interpenetrating networks respond to metal cation concentrations which could be determined from the diffraction color change or precisely monitored by diffraction wavelength shifting using a spectrophotometer. The PVA hydrogel-based photonic crystal sensors could be fabricated in any size and geometry as needed because there is no requirement for a thin sample to allow for penetration of UV light and its processing time is greatly reduced compared with the use of colloidal crystal templates, which has an important significance in the large-scale industrial production in the future.
Co-reporter:Jianhua Shen, Xiaoling Yang, Yihua Zhu, Haigang Kang, Huimin Cao, Chunzhong Li
Biosensors and Bioelectronics 2012 Volume 34(Issue 1) pp:132-136
Publication Date(Web):15 April 2012
DOI:10.1016/j.bios.2012.01.031
We describe the preparation and characterization of a novel type of core–shell hybrid material for application in a novel hydrogen peroxide biosensor, where the structure consists of a continuous gold shell that encapsulates the silica fiber. The SiO2@Au nanofibers had been synthesized by electrospinning silica sol, and then golden seeds were in situ grown on the fiber, lastly the gold-seeded silica fibers were further coated by continuous gold shells. The above nanocomposites had satisfactory chemical stability, excellent biocompatibility and efficient electron transfer property, which may have potential application for the highly sensitive chemical or biological sensors. Cyclic voltammetry (CV) was used to evaluate the electrochemical performance of the SiO2@Au nanocomposites at indium tin oxide (ITO). The biosensor showed high sensitivity and fast response upon the addition of H2O2 and the linear range to H2O2 was from 5 × 10−6 to 1.0 × 10−3 M with a detection limit of 2 μM (S/N = 3). The apparent Michaelis–Menten constant of the biosensor was 1.11 mmol L−1. These results indicated that SiO2@Au nanocomposites have potential for constructing of a variety of electrochemical biosensors.Highlights► We describe the preparation and characterization of SiO2@Au fibers for application in a novel hydrogen peroxide biosensor. ► The SiO2@Au hybrid fibers have high electron transport capacity and biocompatibility due to the perfect network and high surface-to-volume ratio. ► The designed HRP biosensor shows high sensitivity and fast response upon the addition of H2O2.
Co-reporter:Jianmei Zhang, Yihua Zhu, Cheng Chen, Xiaoling Yang, Chunzhong Li
Particuology 2012 Volume 10(Issue 4) pp:450-455
Publication Date(Web):August 2012
DOI:10.1016/j.partic.2011.11.014
A hybrid system of carbon nanotubes (CNTs) coated with poly (amidoamine) (PAMAM) dendrimer-encapsulated platinum nanoparticles (Pt-DENs) and glucose oxidase (GOx) was prepared through the layer-by-layer (LbL) self-assembly approach and then used as anode in enzyme-based biofuel cells (BFCs). The assembly process was monitored by ζ-potential measurement, and the as-resulted Pt-DENs/CNTs nanocomposites were characterized by transmission electron microscopy (TEM). The performance of electrodes modified by Pt-DENs/CNTs was also investigated by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). We found that the Pt-DENs/CNTs could enhance the electron transfer between the redox centers in enzyme and the electrode surfaces. Furthermore, by employing the Pt-DENs/CNTs modified electrodes as anode, the enzyme-based BFCs operated in a solution containing glucose generated an open-circuit voltage of approximately 640.0 mV and a maximum current density of about 90.0 μA/cm2, suggesting that Pt-DENs/CNTs may serve as an alternative anode to previously used noble metals in BFC applications.Graphical abstractSchematic for enzymatic biofuel cell.Highlights► CNTs coated with Pt-DENs and glucose oxidase are prepared via LbL self-assembly. ► The Pt-DENs/CNTs can enhance the electron transfer from enzyme centers to electrode. ► Enzymatic biofuel cells with Pt-DENs/CNTs modified anode show superior performance.
Co-reporter:Kangfu Zhou; Yihua Zhu; Xiaoling Yang; Jinghong Zhou; Chunzhong Li
ChemPhysChem 2012 Volume 13( Issue 3) pp:699-702
Publication Date(Web):
DOI:10.1002/cphc.201100813
Co-reporter:Jie Zong, Yihua Zhu, Xiaoling Yang, Jianhua Shen and Chunzhong Li
Chemical Communications 2011 vol. 47(Issue 2) pp:764-766
Publication Date(Web):10 Nov 2010
DOI:10.1039/C0CC03092A
A novel and facile approach for preparing hydrophilic carbogenic dots (CDs) has been developed with mesoporous silica spheres as nanoreactors by using an impregnation method. The resulting highly efficient photoluminescent CDs without any further treatment are monodisperse, photostable and of low toxicity, and show excellent luminescence properties.
Co-reporter:Cheng Chen, Yihua Zhu, Hua Bao, Jianhua Shen, Hongliang Jiang, Liming Peng, Xiaoling Yang, Chunzhong Li and Guorong Chen
Chemical Communications 2011 vol. 47(Issue 19) pp:5530-5532
Publication Date(Web):04 Apr 2011
DOI:10.1039/C1CC10957J
An ethanol-assisted method is utilized to generate a robust gelated crystalline colloidal array (GCCA) photonic crystal sensor. The functionalized sensor efficiently diffracts the visible light and responds to various stimuli involving solvent, pH, cation, and compressive strain; the related color change can be easily distinguished by the naked eye.
Co-reporter:Jianhua Shen, Yihua Zhu, Cheng Chen, Xiaoling Yang and Chunzhong Li
Chemical Communications 2011 vol. 47(Issue 9) pp:2580-2582
Publication Date(Web):21 Dec 2010
DOI:10.1039/C0CC04812G
A facile hydrazine hydrate reduction of graphene oxide (GO) with surface-passivated by a polyethylene glycol (PEG) method for the fabrication of graphene quantum dots (GQDs) with frequency upconverted emission is presented. And we speculate on the upconversion luminescence due to the anti-Stokes photoluminescence (ASPL), where the δE between the π and σ orbitals is near 1.1 eV.
Co-reporter:Xiaoling Yang, Jindan Lu, Yihua Zhu, Jianhua Shen, Zhen Zhang, Jianmei Zhang, Cheng Chen, Chunzhong Li
Journal of Power Sources 2011 Volume 196(Issue 24) pp:10611-10615
Publication Date(Web):15 December 2011
DOI:10.1016/j.jpowsour.2011.08.111
In this paper, we investigated the use of polyamidoamine (PAMAM) dendrimer-encapsulated platinum nanoparticles (Pt-DENs) as a promising type of cathode catalyst for air-cathode single chamber microbial fuel cells (SCMFCs). The Pt-DENs, prepared via template synthesis method, have uniform diameter distribution with size range of 3–5 nm. The Pt-DENs then loaded on to a carbon substrate. For comparison, we also electrodeposited Pt on carbon substrate. The calculation shows that the loading amount of Pt-DENs on carbon substrate is about 0.1 mg cm−2, which is three times lower than that of the electrodeposited Pt (0.3 mg cm−2). By measuring batch experiments, the results show that Pt-DENs in air-cathode SCMFCs have a power density of 630 ± 5 mW m−2 and a current density of 5200 ± 10 mA m−2 (based on the projected anodic surface area), which is significantly better than electrodeposited Pt cathodes (power density: 275 ± 5 mW m−2 and current density: 2050 ± 10 mA m−2). Additionally, Pt-DENs-based cathodes resulted in a higher power production with 129.1% as compared to cathode with electrodeposited Pt. This finding suggests that Pt-DENs in MFC cathodes is a better catalyst and has a lower loading amount than electrodeposited Pt, and may serve as a novel and alternative catalyst to previously used noble metals in MFC applications.Graphical abstractHighlights► Dendrimer-encapsulated platinum nanocomposites (Pt-DENs) and electrodeposited Pt nanoparticles are prepared as cathodic catalyst of MFCs. ► Compared to electrodeposited Pt- based cathode, the Pt-DENs/carbon paper cathode shows better electrochemical performance and catalytic activity. ► Pt-DENs has improved the oxygen reduction reaction in cathodes and increased the power output to 630 mW m−2.
Co-reporter:Cheng Chen, Yihua Zhu, Hua Bao, Peng Zhao, Hongliang Jiang, Liming Peng, Xiaoling Yang and Chunzhong Li
Soft Matter 2011 vol. 7(Issue 3) pp:915-921
Publication Date(Web):26 Nov 2010
DOI:10.1039/C0SM00923G
We have prepared a solvent-assisted poly(vinyl alcohol) (PVA) gelated crystalline colloidal array (GCCA) photonic crystal material. PVA GCCA was formed by utilizing a well-known freeze-thawing method while the crystalline colloidal array (CCA) was physically immobilized within the PVA hydrogel network. This photonic crystal material could be conveniently fabricated, shaped as needed and efficiently diffracts visible light. The diffraction wavelength can be tuned anywhere within the visible spectrum by simply varying the CCA concentration or stretching the sample. The GCCA demonstrated sol–gel reversible behaviour as the temperature was cycled. It has been observed that the GCCA maintained its ability of diffraction after rehydration, and the sample could be stored for long periods of time at room temperature.
Co-reporter:Kangfu Zhou, Yihua Zhu, Xiaoling Yang, Xin Jiang and Chunzhong Li
New Journal of Chemistry 2011 vol. 35(Issue 2) pp:353-359
Publication Date(Web):25 Nov 2010
DOI:10.1039/C0NJ00623H
The photocatalytic activity of TiO2 is limited by the aggregation of nanoparticles and the fast electron–hole pair recombination. Graphene sheets, with high specific surface area and unique electronic properties, can be used as a good support for TiO2 to enhance the photocatalytic activity. Herein, we prepared graphene–TiO2 (G–TiO2) composites through a one-pot solvothermal reaction by using graphite oxide (GO) and tetrabutyl titanate as starting materials. TiO2 particles with anatase phase and a narrow size distribution were dispersed on the surface of graphene sheets uniformly. The fluorescence quenching confirmed that graphene acted as an electron-acceptor material to effectively hinder the electron–hole pair recombination of TiO2. The product prepared with 30 mg of GO and 8 h of reaction time exhibited excellent photocatalysis to methylene blue (MB) degradation under irradiation of simulated sunlight. Such intriguing photocatalyst may find significant applications in various fields.
Co-reporter:Yujia Jing, Yihua Zhu, Xiaoling Yang, Jianhua Shen, and Chunzhong Li
Langmuir 2011 Volume 27(Issue 3) pp:1175-1180
Publication Date(Web):December 23, 2010
DOI:10.1021/la1042734
Multifunctional core−shell capsules that triggered release by ultrasound stimulus were one-step fabricated by the coaxial electrospray method. The TiO2 shell suppressed the initial burst release of the paclitaxel. Fe3O4 and graphene quantum dots inside the oil core functioned successfully for magnetic targeting and fluorescence imaging, respectively. Paclitaxel was trigger released when the dual layer of titania shell cracked under the ultrasound stimulation, and the releasing profile could be controlled by the length of applied ultrasound time.
Co-reporter:Xiao Han;Xiaoling Yang
Journal of Solid State Electrochemistry 2011 Volume 15( Issue 3) pp:511-517
Publication Date(Web):2011 March
DOI:10.1007/s10008-010-1121-x
A hybrid system of mesoporous silica (MS) particle incorporated with poly(amidoamine) dendrimer-encapsulated platinum nanoparticles (Pt-DENs) was constructed in a neutral aqueous solution through electrostatic interaction. The MS/Pt-DENs composite particles immobilized with glucose oxidase (GOx) were used to modify a glassy carbon electrode for detecting the electrocatalytic response to the reduction of glucose. Pt-DENs can improve the conductivity of MS and enhance the electron transfer between redox centers in enzymes and electrode surfaces. The structure of composite particles and the performance of MS/Pt-DEN-modified electrodes were characterized by transmission electron microscopy, N2 sorption characterization method, electrochemical impedance spectroscopy, cyclic voltammetry and amperometric measurements. The MS/Pt-DENs/GOx-modified electrodes, which had a fast response of GOx less than 3 s, could be used for the determination of glucose ranging from 0.02 to 10 mM. The detection limits were 4 μM at signal-to-noise ratio of 3.
Co-reporter:Xiaoling Yang;Ping Wang
Journal of Solid State Electrochemistry 2011 Volume 15( Issue 4) pp:731-736
Publication Date(Web):2011 April
DOI:10.1007/s10008-010-1147-0
CdSe nanocrystals were prepared within a template of mesoporous silica (MS) spheres via chemical reaction, and then the as-synthesized CdSe/MS composites were dip coated on an optically transparent electrode. The photoelectric properties of CdSe/MS composite film were examined under ultraviolet (UV) illumination at the excitation wavelength of 365 nm. The CdSe/MS composite can facilitate charge rectification and minimize charge recombination as shown by its higher photocurrent. Most importantly, horseradish peroxidase (HRP)-functionalized CdSe/MS-modified electrode (HRP/CdSe/MS) had a stronger response toward hydrogen peroxide (H2O2) under UV illumination than in the dark. The result demonstrates the potential application of HRP/CdSe/MS composite film as a novel biosensor for monitoring H2O2 under UV illumination.
Co-reporter:Yihua Zhu ; Jianhua Shen ; Kangfu Zhou ; Cheng Chen ; Xiaoling Yang ;Chunzhong Li
The Journal of Physical Chemistry C 2011 Volume 115(Issue 5) pp:1614-1619
Publication Date(Web):December 20, 2010
DOI:10.1021/jp109276q
Multifunctional magne-tic composite microspheres which possess the precise control of the size, morphology, surface chemistry, and assembly process of each component have been successfully prepared. These functional nanocomposite microspheres possess a core of silica-protected magnetite particles and in situ growth active gold nanoparticles (ca. 4 nm) on the outer shell by layer-by-layer electrostatic self-assembly. The well-designed microspheres have high magnetization (23.9 emu/g), uniform sphere size (ca. 500 nm), and stably confined and active small Au nanoparticles. As a result, the very little composite microspheres show high performance in catalytic reduction of 4-nitrophenol (with conversion of 95% in 12 min), special convenient magnetic separability, long life, and good reusability. The unique nanostructure makes the microsphere a novel stable and highly efficient catalyst system for various catalytic industry processes.
Co-reporter:Jie Zong, Yihua Zhu, Xiaoling Yang, Chunzhong Li
Materials Science and Engineering: C 2011 Volume 31(Issue 2) pp:166-172
Publication Date(Web):12 March 2011
DOI:10.1016/j.msec.2010.08.014
Monodispersed mesoporous silica spheres (MMSS) with controllable porosity and pore size were successfully prepared by calcination method in the presence of complex salts. The effect of calcination temperature on the pore size of MMSS was examined. The results show that the pore size of MMSS samples can be tuned in the range from 3.20 to 46.80 nm by varying the calcination temperature. It is worth mentioning that the pore size of MMSS can be controlled on a much larger scale by this method compared to the templating approach, by which the pore size can only be expanded up to 10 nm. It is very advantageous for the application in loading enzymes. Moreover, it could be found that the method is feasible, effective and simple. In addition, the use of various MMSS samples as adsorbents for Au nanoparticles of different sizes as well as urease has also been demonstrated. It was confirmed that MMSS with adequate surface charge and optimum matching pore size showed excellent adsorption properties for Au nanoparticles and urease.
Co-reporter:Cheng Chen, Yihua Zhu, Hua Bao, Xiaoling Yang and Chunzhong Li
ACS Applied Materials & Interfaces 2010 Volume 2(Issue 5) pp:1499
Publication Date(Web):April 16, 2010
DOI:10.1021/am100130n
We prepared a poly(vinyl alcohol) (PVA) gelated crystalline colloidal array (GCCA) through physical cross-linking. PVA hydrogel was formed by utilizing a chilling−thawing method while the CCA was physically immobilized within the PVA hydrogel matrix. After being chilled at 2 °C for 24 h, the gel could be formed without disturbing the CCA. With the repetition of chilling−thawing cycle, the hydrogel network was reinforced. This photonic crystal material could be shaped as needed and efficiently diffracts visible light, and the diffraction wavelength can be tuned anywhere within the visible spectrum by simply varying the CCA concentration. The GCCA represents sol−gel reversibility as the temperature is cycled. It has been observed that the GCCA retained its ability of diffraction after rehydration, and the sample could be stored for long periods of time. We further functionalized the PVA hydrogel with Chitosan (CS), and the pH sensing behavior of the PVA/CS GCCA was observed. It revealed that the sensitivity of the PVA/CS GCCA correlates with the CS concentration.Keywords: chitosan;; crystalline colloidal array; hydrogel; poly(vinyl alcohol); sensor
Co-reporter:Kangfu Zhou, Yihua Zhu, Xiaoling Yang, Jie Luo, Chunzhong Li, Shaorong Luan
Electrochimica Acta 2010 Volume 55(Issue 9) pp:3055-3060
Publication Date(Web):30 March 2010
DOI:10.1016/j.electacta.2010.01.035
Graphene was prepared successfully by introducing –SO3− to separate the individual sheets. TEM, EDS and Raman spectroscopy were utilized to characterize the morphology and composition of graphene oxide and graphene. To construct the H2O2 biosensor, graphene and horseradish peroxidase (HRP) were co-immobilized into biocompatible polymer chitosan (CS), then a glassy carbon electrode (GCE) was modified by the biocomposite, followed by electrodeposition of Au nanoparticles on the surface to fabricate Au/graphene/HRP/CS/GCE. Cyclic voltammetry demonstrated that the direct electron transfer of HRP was realized, and the biosensor had an excellent performance in terms of electrocatalytic reduction towards H2O2. The biosensor showed high sensitivity and fast response upon the addition of H2O2, under the conditions of pH 6.5, potential −0.3 V. The time to reach the stable-state current was less than 3 s, and the linear range to H2O2 was from 5 × 10−6 M to 5.13 × 10−3 M with a detection limit of 1.7 × 10−6 M (S/N = 3). Moreover, the biosensor exhibited good reproducibility and long-term stability.
Co-reporter:Haigang Kang, Yihua Zhu, Xiaoling Yang, Yujia Jing, Anezka Lengalova, Chungzhong Li
Journal of Colloid and Interface Science 2010 Volume 341(Issue 2) pp:303-310
Publication Date(Web):15 January 2010
DOI:10.1016/j.jcis.2009.09.050
Mesoporous silica nanofibers and Ag-doped composite nanoribbons were synthesized by a facile combination of an electrospinning technique and the sol–gel method. Tetraethyl orthosilicate, polyvinylpyrrolidone (PVP), triblock poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide), copolymer Pluronic P123, and silver nitrate (AgNO3) were the components of sol for the production of Ag-doped hybrid silica ribbons. Heat removal of structure-directing agent P123 in the hybrid fibers at high temperatures resulted in a mesoporous morphology, and the degradation of PVP caused AgNO3 to convert into silver in the form of nanoparticles. The size and content of the particles in the hybrid ribbons could be controlled by the concentration of AgNO3 and thermal treatment conditions. Scanning electron microscopy, N2 adsorption–desorption isotherm, transmission electron microscopy, X-ray diffraction, and UV–Vis spectroscopy were used to characterize the composite ribbons. The catalytic activity of the ribbons was evaluated by reduction of methylene blue dye and found to be better than in previous studies.The silver-doped mesoporous silica nanobibbons had been synthesized by combining the electrospinning technique and sol–gel method, which demonstrated high catalytic efficiency for reduction reaction of methylene blue dye (MB).
Co-reporter:Kangfu Zhou, Yihua Zhu, Xiaoling Yang and Chunzhong Li
New Journal of Chemistry 2010 vol. 34(Issue 12) pp:2950-2955
Publication Date(Web):31 Aug 2010
DOI:10.1039/C0NJ00283F
A one-pot solvothermal reaction was used to prepare graphene/Fe3O4 composites using graphite oxide and FeCl3·6H2O as starting materials. Graphene oxide was reduced to graphene and the Fe3O4 microspheres were simultaneously grown on the carbon basal planes under the conditions generated in the solvothermal system. The product showed a high crystallinity of magnetite and a considerable saturation magnetization. The size and density of the Fe3O4 microspheres distributed on the graphene can be easily controlled by altering the starting Fe3+ concentration. Doxorubicin hydrochloride was loaded on to the graphene/Fe3O4 composites by simple mixing, and a saturation loading capacity as high as 65% could be achieved.
Co-reporter:Haigang Kang, Yihua Zhu, Xiaoling Yang, Jianhua Shen, Cheng Chen and Chunzhong Li
New Journal of Chemistry 2010 vol. 34(Issue 10) pp:2166-2175
Publication Date(Web):11 Jun 2010
DOI:10.1039/C0NJ00094A
Mesostructured silica fibers synthesized by electrospinning silica sol were used as templates for the assembly of gold nanoparticles and the formation of continuous gold shells along the fiber axis. Dense and uniform spherical gold nanoparticles were formed by in situ reduction of hydrochloroauric acid absorbed on self-assembled polyelectrolyte film of silica fiber surface. The gold-seeded silica fibers were further coated by continuous gold shells via solution-phase reduction of an appropriate metal ion in PVP solution. The thickness and morphology of gold shell could be tailored by the molar ratio of repeating units of PVP to gold ions (R) and growth time. Experimental results showed that low R tended to form a thick gold layer with sharp tips, whereas high R favored obtaining thin and uniform Au shell. The SiO2@Au fiber hybrid nanostructures are further used as substrates for fabrication of a glucose biosensor, which exhibited excellent bio-electrochemical activity with high sensitivity and rapid response. These hybrid nanostructures are, therefore, regard as molecule wires for potential application in highly sensitive chemical or biological sensors.
Co-reporter:Huimin Cao, Yihua Zhu, Xi Tan, Haigang Kang, Xiaoling Yang and Chunzhong Li
New Journal of Chemistry 2010 vol. 34(Issue 6) pp:1116-1119
Publication Date(Web):26 Feb 2010
DOI:10.1039/B9NJ00737G
The electrospinning method coupled with a chemical reaction is employed to fabricate a TiO2/CdS composite fiber. The concentration of CdS can be changed by varying the amount of CdCl2 present as the crystal seed in the precursor sol. The DRUV-Vis spectra results show that the TiO2/CdS composite fiber absorbs both in the UV and visible regions. The results of TEM, XRD, PL, CLSM and Raman spectra also confirm the formation of CdS in TiO2 fibers.
Co-reporter:Zhen Zhang, Yihua Zhu, Xiaoling Yang, Chunzhong Li
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2010 Volume 362(1–3) pp:135-139
Publication Date(Web):5 June 2010
DOI:10.1016/j.colsurfa.2010.04.006
A novel preparation method of azithromycin (AZI) microcapsules based on hollow polyelectrolyte (PE) microcapsules, which were prepared by layer-by-layer self-assembly onto the surface of silica microsphere (SiO2) followed by core dissolution has been investigated. The prepared AZI/PE microcapsules with an average diameter 1.2 μm possess homogeneous size and regular spherical shape. FTIR spectra and XRD patterns indicated that AZI molecular structure was not changed and AZI crystal state changed from monohydrate to dihydrate. The drug release experimental results showed an obvious improvement in the dissolution rate of the prepared AZI/PE microcapsules in comparing with AZI raw material drug powder.
Co-reporter:Haigang Kang, Yihua Zhu, Jianhua Shen, Xiaoling Yang, Cheng Chen, Huimin Cao, Chungzhong Li
Materials Research Bulletin 2010 45(7) pp: 830-837
Publication Date(Web):
DOI:10.1016/j.materresbull.2010.03.010
Co-reporter:Xiao Han;Xiaoling Yang;Chunzhong Li
Microchimica Acta 2010 Volume 171( Issue 3-4) pp:233-239
Publication Date(Web):2010 December
DOI:10.1007/s00604-010-0424-z
A hybrid system was constructed in neutral aqueous solution that consisted of clay clusters incorporated with platinum nanoparticles that were encapsulated with a poly(amidoamine) dendrimer through electrostatic interaction. Glucose oxidase was immobilized in this hybrid and used to modify a glassy carbon electrode so to obtain an enzymatic glucose biosensor. The nanohybrid material and the sensor were characterized by cyclic voltammetry and amperometry. The sensor has a response time of <3 s and a dynamic range from 0.01 to 16 mM. The detection limit is 4 μM at a signal-to-noise ratio of 3.
Co-reporter:Haigang Kang, Yihua Zhu, Yujia Jing, Xiaoling Yang, Chungzhong Li
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2010 Volume 356(1–3) pp:120-125
Publication Date(Web):5 March 2010
DOI:10.1016/j.colsurfa.2010.01.009
Mesoporous Ag-doped silica nanostructured ribbons were first synthesized by a facile combination of electrospinning technique and sol–gel method. Tetraethyl orthosilicate, polyvinylpyrrolidone (PVP), triblock poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) copolymer Pluronic P123 and silver nitrate (AgNO3) were the components of sol for the production of Ag-doped hybrid silica ribbons. Heat removal of structure-directing agent P123 in the hybrid fibers at high temperatures resulted in mesoporous morphology, and the degradation of PVP made AgNO3 convert into silver in the form of nanoparticles. SEM, TEM, XRD, and UV–vis spectroscopy were used to characterize the ribbons. The ribbons with high width/height ratio have uniform and continuous morphology. Faradaic-impedance spectra and cyclic voltammetry test show that the ribbons have excellent ability of electron transition and electrochemical activity, expected to have potential application in biosensing system.
Co-reporter:Yihua Zhu, Huimin Cao, Longhua Tang, Xiaoling Yang, Chunzhong Li
Electrochimica Acta 2009 Volume 54(Issue 10) pp:2823-2827
Publication Date(Web):1 April 2009
DOI:10.1016/j.electacta.2008.11.025
Three-dimensional macroporous TiO2 was synthesized by a sol–gel procedure using polystyrene colloidal crystals as templates. SEM showed that a face-centered cubic (FCC) 3D macroporous structure was obtained. Horseradish peroxidase (HRP) was successfully immobilized on the surface of an optically transparent electrode (OTE). Photoelectrochemical properties were characterized using a three electrodes system and an ultraviolet lamp. The HRP/TiO2/OTE displays a rapid photocurrent response, approximately 178.7 nA, under UV illumination (380 nm). The sensitivity of H2O2 detection was 70.04 μA/mM without UV illumination, and it increased to 102.97 μA/mM when illuminated by UV. The amperometric response was also enhanced. The high response was due to the good biocompatibility of TiO2 and excellent photoelectrical property and the large effective surface of the three-dimensionally ordered macroporous structure.
Co-reporter:Yaoxia Li, Yihua Zhu, Cuiyan Li, Xiaoling Yang, Chunzhong Li
Materials Letters 2009 Volume 63(Issue 12) pp:1068-1070
Publication Date(Web):15 May 2009
DOI:10.1016/j.matlet.2009.02.007
The ZnS nanoparticles were exclusively synthesized in the pores of the mesoporous silica (MS) particles which had been coated with two bilayers of poly(allylamine hydrochloride) (PAH)/poly(styrene sulfonate) (PSS) via the layer-by-layer (LbL) self-assembly technique. Measurements and analysis of XRD and TEM showed that the ZnS nanocrystals were inserted into the pores of the MS spheres. This approach can be used to prepare composite materials involving functional inorganic nanoparticles which have potential application in biological immunoassay and photoelectronic fields.
Co-reporter:Jinjie Sun, Yihua Zhu, Xiaoling Yang, Chunzhong Li
Particuology 2009 Volume 7(Issue 5) pp:347-352
Publication Date(Web):October 2009
DOI:10.1016/j.partic.2009.04.009
A novel photoelectrochemical biosensor incorporating nanosized CdS semiconductor crystals with enzyme to enhance photochemical reaction has been investigated. CdS nanoparticles were synthesized by using dendrimer PAMAM as inner templates. The CdS nanoparticles and glucose oxidase (GOD) were immobilized on Pt electrode via layer-by-layer (LbL) technique to fabricate a biological–inorganic hybrid system. Under ultraviolet light, the photo-effect of the CdS nanoparticles showed enhancement of the biosensor to detect glucose. Pt nanoparticles were mixed into the Nafion film to immobilize the CdS/enzyme composites and to improve the charge transfer of the hybrid. Experimental results demonstrate the desirable characteristics of this biosensing system, e.g. a sensitivity of 1.83 μA/(mM cm2), lower detection limit (1 μM), and acceptable reproducibility and stability.
Co-reporter:Lihuan Xu, Yihua Zhu, Xiaoling Yang, Chunzhong Li
Materials Science and Engineering: C 2009 29(4) pp: 1306-1310
Publication Date(Web):
DOI:10.1016/j.msec.2008.10.031
Co-reporter:Ping Wang, Yihua Zhu, Xiaoling Yang, Chunzhong Li, H.L. Du
Acta Materialia 2008 Volume 56(Issue 5) pp:1144-1150
Publication Date(Web):March 2008
DOI:10.1016/j.actamat.2007.11.006
Abstract
Semiconductor materials composed of CdSe nanocrystals (NCs) were synthesized in the pores of mesoporous silica (MS) through direct reaction between Cd ions and a selenosulfate solution at low temperatures (from −10 °C to room temperature). The negatively charged MS favours a coating of the positively charged Cd composite. Thus, Cd ions were adsorbed to the Si–OH groups to form Cd–O–Si through electrostatic interaction. The sizes of the CdSe nanocrystals were mainly determined by the pore size of the MS spheres. After expanding the pore size of MS spheres, two different pore sizes were found: ∼3.2 and ∼9.7 nm. Thus, two differently sized CdSe nanocrystals were formed in the pores of MS spheres. The size of CdSe nanocrystals showed a dependence on the pore size of the MS spheres. This result is believed to involve the photoluminescence (PL) band originating from band-to-band transition or surface states. Measurements and analysis of X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy, energy-dispersive spectrometry, selected area electron diffraction and PL spectra showed that the CdSe nanocrystals obtained had good crystallinity and were almost perfectly inserted into the pores of the MS spheres, which created a fluorescence emission.
Co-reporter:Yaoxia Li, Yihua Zhu, Xiaoling Yang and Chunzhong Li
Crystal Growth & Design 2008 Volume 8(Issue 12) pp:4494-4498
Publication Date(Web):October 24, 2008
DOI:10.1021/cg800457u
CdS nanoparticles were exclusively synthesized in the pores of mesoporous silica (MS) particles that had been coated with two bilayers of poly(allylamine hydrochloride) (PAH)/poly(styrene sulfonate) (PSS) via the layer-by-layer (LbL) self-assembly technique. The PAH/PSS multilyers film could prevent generation of nanocrystals outside the MS spheres. After removal of the silica cores, CdS nanocrystal encapsulated microcapsules were obtained confirming that numerous CdS nanocrystals were successfully formed. The sizes of the CdS nanocrystals were mainly determined by the pore size of the MS spheres. After being treated with a mixed solution of three salts including NaCl, LiCl, and KNO3, the MS spheres showed two different pore sizes of 3.2 and 9.7 nm. Thus, two differently sized (3.2 nm, 6.8 nm) CdS nanocrystals were formed in the pores of MS spheres. This result is believed to explain the photoluminescence (PL) band originating from band-to-band transition. Measurements and analysis of X-ray diffraction, transmission electron microscopy, high-resolution TEM, photoluminescence spectra and confocal laser scanning microscopy showed that the CdS nanocrystals were almost perfectly inserted into the pores of the MS spheres and had good crystallinity, which created a fluorescence emission. This approach can be used to prepare composite materials involving functional inorganic nanoparticles, which have potential application in biological immunoassay and photoelectronic fields.
Co-reporter:Lihuan Xu;Longhua Tang;Xiaoling Yang ;Chunzhong Li
Journal of Applied Polymer Science 2008 Volume 109( Issue 3) pp:1802-1807
Publication Date(Web):
DOI:10.1002/app.28307
Abstract
A novel amperometric glucose biosensor based on self-assembling glucose oxidase (GOx) and dendrimer-encapsulated Pt nanoparticles (Pt-DENs) on nanofibrous polyaniline (PANI) was described. PANI nanofibers were synthesized via an interfacial polymerization method. A sulfonated polyelectrolytes-poly(sodium 4-styrenesulfonate) (PSS) was used to form the negative PANI/sulfonated polyelectrolyte complex, which had good disperse in aqueous solution. GOx was immobilized on the PANI/PSS surface by alternatively assembling a cationic Pt-DENs layer and an anionic GOx layer. The unique sandwich-like layer structure (Pt-DENs/GOx/Pt-DENs/PANI/PSS) formed by self-assembling provides a favorable microenvironment to keep the bioactivity of GOx and to prevent enzyme molecule leakage. The fabricated Pt-DENs/GOx/Pt-DENs/PANI/PSS electrode exhibited excellent response performance to glucose with a detection limit of 0.5 μM, wide linear range from 10 μM to 4.5 mM, short response time within 5 s, improved sensitivity of 39.63 μA/(mM cm2), and good stability (85% remains after 20 days). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Co-reporter:Longhua Tang, Yihua Zhu, Xiaoling Yang, Chunzhong Li
Analytica Chimica Acta 2007 Volume 597(Issue 1) pp:145-150
Publication Date(Web):30 July 2007
DOI:10.1016/j.aca.2007.06.024
An enhanced amperometric biosensor based on incorporating one kind of unique nanobiocomposite as dopant within an electropolymerized polypyrrole film has been investigated. The nanobiocomposite was synthesized by self-assembling glutamate dehydrogenase (GLDH) and poly(amidoamine) dendrimer-encapsulated platinum nanoparticles (Pt-DENs) onto multiwall carbon nanotubes (CNTs). ζ-Potentials and high-resolution transmission electron microscopy (HRTEM) confirmed the uniform growth of the layer-by-layer nanostructures onto the carboxyl-functionalized CNTs. The size of Pt nanoparticles is approximately 3 nm. The (GLDH/Pt-DENs)n/CNTs/Ppy hybrid film was obtained by electropolymerization of pyrrole onto glassy carbon electrodes and characterized with scanning electron microscopy (SEM), cyclic voltammetry (CV) and other electrochemical measurements. All methods indicated that the (GLDH/Pt-DENs)n/CNTs nanobiocomposites were entrapped within the porous polypyrrole film and resulted in a hybrid film that showed a high electrocatalytic ability toward the oxidation of glutamate at a potential 0.2 V versus Ag/AgCl. The biosensor shows performance characteristics with high sensitivity (51.48 μA mM−1), rapid response (within 3 s), low detection limit (about 10 nM), low level of interference and excellent reproducibility and stability.
Co-reporter:Fei Guo, Yihua Zhu, Xiaoling Yang, Chunzhong Li
Materials Chemistry and Physics 2007 Volume 105(2–3) pp:315-319
Publication Date(Web):15 October 2007
DOI:10.1016/j.matchemphys.2007.04.077
PAMAM–CdS nanocomposites with their photoluminescence property were prepared in methanol solution and the ratio of Cd2+ and PAMAM was adjusted to investigate its effect on the optical property of the PAMAM–CdS nanocomposites. The formed PAMAM–CdS nanocomposites were adsorbed onto the melamine formaldehyde (MF) microspheres by electrostatic interaction to form microspheres with their photoluminescence property. Electrostatic layer-by-layer assembly of the PAMAM–CdS nanocomposites using poly(sodium 4-styrenesulfonate) (PSS) as the oppositely charged polyelectrolyte leading to MF microspheres with their photoluminescence intensity is reported. The formed composite microspheres can be applied in the fields such as biological assays.
Co-reporter:Yi Jin, Yihua Zhu, Xiaoling Yang, Chuan Wei, Chunzhong Li
Materials Chemistry and Physics 2007 Volume 106(2–3) pp:209-214
Publication Date(Web):15 December 2007
DOI:10.1016/j.matchemphys.2007.05.047
Cerium-doped titania inverted opals with powder and film morphologies were synthesized from cerous nitrate and tetrabutyl titanate in the interstitial spaces of a polystyrene opal. This procedure involves infiltration of precursors into the interstices of the polystyrene opal template followed by hydrolytic polycondensation of the precursors to amorphous titania and removal of the polystyrene opal by calcination. The morphologies of opal and inverse opal were characterized by scanning electron microscope (SEM). Powder X-ray diffraction (XRD) allows one to observe the influence of doping degree on the grain size. And the XPS investigation showed the doping structure of cerium. The synthesis of cerium-doped titania inverted opals provides an opportunity to electrically and optically engineer the photonic band structure and the possibility of developing tunable three-dimensional photonic crystal devices.
Co-reporter:Yi Jin, Yihua Zhu, Xiaoling Yang, Chunzhong Li, Jinghong Zhou
Journal of Solid State Chemistry 2007 Volume 180(Issue 1) pp:301-306
Publication Date(Web):January 2007
DOI:10.1016/j.jssc.2006.10.015
Co-reporter:Longhua Tang, Yihua Zhu, Lihuan Xu, Xiaoling Yang, Chunzhong Li
Talanta 2007 Volume 73(Issue 3) pp:438-443
Publication Date(Web):30 September 2007
DOI:10.1016/j.talanta.2007.04.008
A novel amperometric biosensor based on self-assembling glutamate dehydrogenase (GLDH) and poly(amidoamine) dendrimer-encapsulated platinum nanoparticles (Pt-PAMAM) onto multiwall carbon nanotubes (CNTs) has been developed for the determination of glutamate. The formation of the self-assembled (GLDH/Pt-PAMAM)n/CNTs construction was investigated by ζ-potential and high resolution transmission electron microscopy (HRTEM). The results indicated the uniform growth of the layer-by-layer nanostructures onto carboxyl-functionalized CNTs. The electrocatalytic property of the (GLDH/Pt-PAMAM)n/CNTs modified electrode to glutamate in presence of NAD+ (β-nicotinamide adenine dinucleotide, 0.1 mM) was investigated at a low overpotential 0.2 V by electrochemical measurements. The results showed it had series of attractive characteristics, such as a large determination range (0.2–250 μM), a short response time (within 3 s), a high sensitivity (433 μA/mM−1 cm2) and good stability (85% remains after 4 weeks).
Co-reporter:Chuan Wei, Yihua Zhu, Xiaoling Yang, Chunzhong Li
Materials Science and Engineering: B 2007 Volume 137(1–3) pp:213-216
Publication Date(Web):25 February 2007
DOI:10.1016/j.mseb.2006.11.016
A class of hybrid organic–inorganic composite for application in electrorheological (ER) fluid was prepared by using a simple one-pot method. Transmission electron microscopy (TEM) image shows that the synthesized material had a mesoporous structure. X-ray diffraction (XRD) further proves that the pore size is about 7.4 nm with an anatase TiO2 framework. Fourier transform infrared (FT-IR) and nitrogen sorption curve reveal polyaniline (PANI) is doped in mesochannels. The ER behaviors of PANI/TiO2 in silicone oil are invesigated with different doping degrees under different electric fields. The results obtained provide more insight into the role of proper doping in ER fluid.
Co-reporter:Yihua Zhu, Hong Da, Xiaoling Yang, Ying Hu
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2003 Volume 231(1–3) pp:123-129
Publication Date(Web):31 December 2003
DOI:10.1016/j.colsurfa.2003.08.020
Core-shell monodispersed magnetic silica microspheres with tailored dimensions and compositions have been fabricated by consecutively assembling magnetite (Fe3O4) nanoparticles and polyelectrolyte onto silica microspheres. The layers were deposited under conditions where Fe3O4 and poly(diallyldimethylammonium chloride) (PDADMAC) are oppositely charged, thereby utilizing electrostatic attractions for multiplayer buildup. The alternating ζ-potentials and transmission electron microscopy (TEM) measurements provided direct evidence of the stepwise multilayers growth, and the elemental Auger electron spectroscopy (AES) depth profile of core-shell magnetic silica microspheres indicate that the contents of Fe and C decrease but the contents of Si and O increase with sputtering. The fabrication of these magnetic silica microspheres is expected to produce novel particles with potential applications in various fields of materials science and biotechnology.
Co-reporter:Jianhua Shen, Yunfeng Li, Yihua Zhu, Xiaoling Yang, Xiuzhong Yao, Jun Li, Guangjian Huang and Chunzhong Li
Journal of Materials Chemistry A 2015 - vol. 3(Issue 14) pp:NaN2882-2882
Publication Date(Web):2015/02/18
DOI:10.1039/C5TB00041F
The facile fabrication of Gd-labeled superparamagnetic Fe3O4 nanoparticles (NPs) and fluorescent CuInS2 (CIS) quantum dots conjugated with arginine-glycine-aspartic acid (RGD) peptides has been demonstrated, for tri-mode targeted T1-, T2-weighted magnetic resonance (MR) and fluorescence imaging of pancreatic cancer. The core–shell nanocomposites formed are water-dispersible, stable and biocompatible, as confirmed by MTT assay on BXPC-3 cells. Relaxivity measurements show a T1 relaxivity (r1) of 1.56 mM−1 s−1 and a T2 relaxivity (r2) of 23.22 mM−1 s−1, which enable T1- and T2-weighted MR imaging of cancer cells in vitro and in vivo. The MR imaging data clearly indicate that the multifunctional NPs can specifically target cancer cells with αvβ3 integrin over-expression on the cell surface, through a receptor-mediated delivery pathway. The T1-weighted positive and T2-weighted negative enhancement in the MR imaging significantly improves the diagnosis accuracy, and fluorescence imaging of tumor tissue can assist in clinical surgery. These findings suggest that these multifunctional NPs could be used as a platform for bimodal imaging (both MR and fluorescence) in various biological systems.
Co-reporter:Xiaoling Yang, Hua Zhong, Yihua Zhu, Jianhua Shen and Chunzhong Li
Dalton Transactions 2013 - vol. 42(Issue 39) pp:NaN14330-14330
Publication Date(Web):2013/07/29
DOI:10.1039/C3DT51686E
Metallic nanoparticle (NP) decorated silicon nanowire (SiNW) heterostructures show significant promise in enhanced optical and opto-electrical properties due to the coupling of surface plasmon to nanowires. Here, recyclable Au-decorated silicon nanowire arrays (Au-SiNWAs) as surface-enhanced Raman scattering (SERS) substrates were successfully fabricated by a simple galvanic displacement reaction. The influence of different average size and aggregation level of Au NPs on SERS activity was explored. The SERS activity of the substrates strongly depends on the average size and aggregation level of Au NPs on the surface of the SiNWs, and the most optimal size and separation of AuNPs on the SiNWs can be achieved by controlling the reaction time. The optimized Au-SiNWA substrate exhibits ultrahigh sensitivity with an enhancement factor of 109, and is able to detect the analyte molecule at a concentration as low as 10−11 M. More importantly, the SERS substrate is recyclable, as enabled by a self-cleaning function due to UV light photocatalytic degradation of the analyte molecules. The high sensitivity and recyclability of the Au-SiNWA SERS substrate is demonstrated by the detection of a model molecule rhodamine B (RhB). Our studies show that the unique Au-SiNWA SERS substrates have significant potential to put SERS into wider application.
Co-reporter:Peng Zhao, Jing Zhang, Yihua Zhu, Xiaoling Yang, Xin Jiang, Yuan Yuan, Changsheng Liu and Chunzhong Li
Journal of Materials Chemistry A 2014 - vol. 2(Issue 47) pp:NaN8377-8377
Publication Date(Web):2014/10/03
DOI:10.1039/C4TB01445F
A highly efficient multifunctional nanoplatform for dual-modal luminescence imaging and pH-responsive drug delivery has been developed on the basis of a facile and novel strategy by covalently binding up-conversion (UC) luminescent NaYF4:Yb,Er nanoparticles with down-conversion (DC) fluorescent AgInS2–ZnS quantum dots. Due to the enriched carboxylic groups in the polymer shell of UC nanoparticles, the as-prepared nanocomposites (NCs) are water-soluble, functionalizable and able to load anti-cancer drug molecules, doxorubicin (DOX), by simple physical adsorption. The release of DOX from NCs was controlled by varying the pH, with an increased drug dissociation rate in an acidic environment, favorable for controlled drug release. Moreover, the endocytosis and the efficient drug release properties of the system were confirmed by luminescence microscopy. Hence, this approach provides a valuable method for fabricating a NC system with highly integrated functionalities for dual-modal luminescence cell imaging and targeted cancer therapy.
Co-reporter:Xiaoling Yang, Kaicai Fan, Yihua Zhu, Jianhua Shen, Xin Jiang, Peng Zhao and Chunzhong Li
Journal of Materials Chemistry A 2012 - vol. 22(Issue 33) pp:NaN17283-17283
Publication Date(Web):2012/06/22
DOI:10.1039/C2JM32571C
Graphene-encapsulated mesoporous Co3O4 microspheres have been successfully fabricated through a facile self-assembly approach. Driven by the mutual electrostatic interactions, the mesoporous Co3O4 microspheres prepared by a nanocasting method are fully wrapped by graphene shells. We performed the evaluation as anode materials for Li-ion batteries: the composites exhibit a first discharge capacity of 1533 mA h g−1 and rapidly stabilize while remaining at a reversible capacity up to 820 mA h g−1 during all the discharge–charge cycles at a current of 100 mA g−1. The substantially improved electrochemical performance of the Co3O4–graphene composites were ascribed to the synergistic effects between the conductive graphene shells and mesoporous Co3O4 microspheres. Notably, the graphene shells not only act as buffers to accommodate the volume variation of Co3O4 but also serve as the reliable conductive channels of the electrode. In addition, the mesostructure of the mesoporous Co3O4 microspheres provides extra space for the storage of Li+ and significantly reduces paths for both Li+ ion and electron diffusion.
Co-reporter:Cheng Chen, Yihua Zhu, Hua Bao, Jianhua Shen, Hongliang Jiang, Liming Peng, Xiaoling Yang, Chunzhong Li and Guorong Chen
Chemical Communications 2011 - vol. 47(Issue 19) pp:NaN5532-5532
Publication Date(Web):2011/04/04
DOI:10.1039/C1CC10957J
An ethanol-assisted method is utilized to generate a robust gelated crystalline colloidal array (GCCA) photonic crystal sensor. The functionalized sensor efficiently diffracts the visible light and responds to various stimuli involving solvent, pH, cation, and compressive strain; the related color change can be easily distinguished by the naked eye.
Co-reporter:Peng Zhao, Yihua Zhu, Xiaoling Yang, Jianhua Shen, Xin Jiang, Jie Zong and Chunzhong Li
Dalton Transactions 2014 - vol. 43(Issue 2) pp:NaN457-457
Publication Date(Web):2013/09/06
DOI:10.1039/C3DT52066H
We report on a novel drug carrier which is based on the combination of magnetic and upconversion (UC) emission of Fe3O4@SiO2/NaYF4:Yb, Er (MSU) hybrids modified with MnO2 nanosheets (MSU/MnO2). The MSU hybrids were fabricated by covalently linking amino-modified Fe3O4@SiO2 particles with carboxyl-functionalized NaYF4:Yb, Er particles. The Fe3O4 core and the NaYF4:Yb, Er shell functioned successfully for magnetic targeting and fluorescence imaging, respectively. MnO2 nanosheets served as drug carriers and UC luminescence quenchers. The drug can be released by introducing glutathione (GSH) which reduces MnO2 to Mn2+, and at the same time, UC luminescence can be turned on. These results clearly show that these MSU/MnO2 nanocomposites are promising platforms which can be applied to construct a smart drug delivery system with magnetic targeting and GSH-stimulation, as well as tracking by UC luminescence.
Co-reporter:Jianhua Shen, Yihua Zhu, Kangfu Zhou, Xiaoling Yang and Chunzhong Li
Journal of Materials Chemistry A 2012 - vol. 22(Issue 2) pp:NaN550-550
Publication Date(Web):2011/11/02
DOI:10.1039/C1JM13216D
Due to the fast electron transportation and good biocompatibility, the use of graphene in biosensors is becoming more and more appealing. But a key challenge is how to obtain well-organized 2D or 3D graphene structures to build larger objects, and the development of methods for controlling the organization of functional objects on a nanometre scale to build larger objects is of fundamental and technological interest. To overcome this problem, we demonstrate a novel strategy for the fabrication of a reduced graphene oxide-encapsulated multifunctional magnetic composite microspheres (rGOE-Ms)-based anisotropic conductive film (ACF). The well-designed rGOE-Ms possess both magnetization and good electron transport properties. Magnetic properties can be detected by their movement in the gel film under an external magnet. Most interestingly, the prepared gel film has displayed the existence of rGOE-Ms alignment and anisotropy in the ACF, and the electrical resistivity of the vertical ACF was almost fifteen times higher than the horizontal. Therefore, the ACF can be extended to various advanced applications, such as chemical/biosensors, nanoelectronics, and so on.
Co-reporter:Hongliang Jiang, Yihua Zhu, Yunhe Su, Yifan Yao, Yanyan Liu, Xiaoling Yang and Chunzhong Li
Journal of Materials Chemistry A 2015 - vol. 3(Issue 24) pp:NaN12645-12645
Publication Date(Web):2015/05/14
DOI:10.1039/C5TA02792F
A bottom-up approach was introduced to prepare nitrogen and phosphorus dual-doped multilayer graphene with a high dopant content and well-developed porosity, which leads to high catalytic activity in the hydrogen evolution reaction with the comparable onset overpotential (0.12 V) and Tafel slope (79 mV per decade) to some of the traditional metallic catalysts.
Co-reporter:Xiaoling Yang, Hua Zhong, Yihua Zhu, Hongliang Jiang, Jianhua Shen, Jianfei Huang and Chunzhong Li
Journal of Materials Chemistry A 2014 - vol. 2(Issue 24) pp:NaN9047-9047
Publication Date(Web):2014/02/26
DOI:10.1039/C4TA00119B
Non-noble metal copper (Cu) nanoparticles (NPs) with controlled size and surface coverage are decorated on silicon nanowire arrays (SiNWAs) by a simple galvanic displacement reaction. Using the combined efforts of all these approaches, SiNWAs-supported Cu NPs (SiNWAs–Cu) exhibit excellent and stable activity for the catalytic reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by sodium borohydride (NaBH4) in an aqueous solution, which can be recycled for five successive cycles of the reaction with a conversion efficiency of more than 95%. This novel catalyst also shows excellent catalytic performance for the degradation of other organic dyes, such as methylene blue (MB) and rhodamine B (RhB). Additionally, we demonstrate that the catalytic activity of SiNWAs–Cu is comparable to other SiNWAs-supported noble metal NPs (i.e., Ag and Au). Furthermore, SiNWAs as powerful substrates can be reused for decorating with Cu NPs after dilute HNO3 treatment. SiNWAs–Cu is particularly attractive as a catalyst, although Cu is orders of magnitude cheaper than any noble metals, its catalytic performance is comparable to other noble metals. So SiNWAs–Cu is thus expected to have the potential as a highly efficient, cost-effective and eco-friendly reusable catalyst to replace noble metals for certain catalytic applications.
Co-reporter:Jianfei Huang, Huailong Li, Yihua Zhu, Qilin Cheng, Xiaoling Yang and Chunzhong Li
Journal of Materials Chemistry A 2015 - vol. 3(Issue 16) pp:NaN8741-8741
Publication Date(Web):2015/03/16
DOI:10.1039/C5TA00847F
Commercial copper foams have been tailored by a highly scalable method combining room-temperature wet-chemical etching and hydroxide thermolysis into a three-dimensional copper oxide nanowire array–copper (3D-CuONA–Cu) composite with macroporous voids and large-area fur-like nanowire array structures, whose structures and compositions were studied employing electron microscopy, X-ray diffraction (XRD) and Raman spectroscopy. The 3D-CuONA–Cu composite monolith was used as a free-standing electrode for pseudo-capacitive energy storage and enzyme-free H2O2 detection. Thanks to the 3D electrode architecture and the high-density in situ formed electroactive nanoarrays, an enhanced capacitance of 608 mF cm−2 at 2 mV s−1 was achieved, with an 88.6% capacity retention after 4000 cycles observed at the high current density of 30 mA cm−2. For enzyme-free H2O2 sensing, an extraordinary sensitivity of 5.75 mA mM−1 cm−2 and a low detection limit of 0.56 μM were achieved. This prototype sensor also exhibited eligible selectivity and feasibility for real sample analysis.
Co-reporter:Yunhe Su, Hongliang Jiang, Yihua Zhu, Xiaoling Yang, Jianhua Shen, Wenjian Zou, Jianding Chen and Chunzhong Li
Journal of Materials Chemistry A 2014 - vol. 2(Issue 20) pp:NaN7287-7287
Publication Date(Web):2014/02/21
DOI:10.1039/C4TA00029C
Graphitic N is proposed to be one of the most likely active sites for the oxygen reduction reaction (ORR) in N-doped carbon materials. However, the recent hybrid composites consisting of N-doped carbons and transition metal oxides for the ORR are predominantly pyridinic N- and pyrrolic N-doped carbon-supported cobalt or manganese oxides. Here, an enriched graphitic N-doped carbon-supported Fe3O4 nanoparticles composite was prepared via a solvothermal carbonization process. The hybrid composite exhibits a similar high catalytic activity with the 4e− reaction pathway but superior stability to Pt/C for the ORR in alkaline media. Furthermore, the composite also shows a better ORR performance than previously reported transition metal oxides-based N-doped carbon hybrid composites. The unusual high catalytic activity arises from the combination of the high surface area and the synergetic coupling effect between the enriched graphitic N-doped carbon and Fe3O4 nanoparticles.
Co-reporter:Jianhua Shen, Yihua Zhu, Cheng Chen, Xiaoling Yang and Chunzhong Li
Chemical Communications 2011 - vol. 47(Issue 9) pp:NaN2582-2582
Publication Date(Web):2010/12/21
DOI:10.1039/C0CC04812G
A facile hydrazine hydrate reduction of graphene oxide (GO) with surface-passivated by a polyethylene glycol (PEG) method for the fabrication of graphene quantum dots (GQDs) with frequency upconverted emission is presented. And we speculate on the upconversion luminescence due to the anti-Stokes photoluminescence (ASPL), where the δE between the π and σ orbitals is near 1.1 eV.
Co-reporter:Jianhua Shen, Yihua Zhu, Xiaoling Yang and Chunzhong Li
Chemical Communications 2012 - vol. 48(Issue 31) pp:NaN3699-3699
Publication Date(Web):2012/02/21
DOI:10.1039/C2CC00110A
Similar to the popular older cousins, luminescent carbon dots (C-dots), graphene quantum dots or graphene quantum discs (GQDs) have generated enormous excitement because of their superiority in chemical inertness, biocompatibility and low toxicity. Besides, GQDs, consisting of a single atomic layer of nano-sized graphite, have the excellent performances of graphene, such as high surface area, large diameter and better surface grafting using π–π conjugation and surface groups. Because of the structure of graphene, GQDs have some other special physical properties. Therefore, studies on GQDs in aspects of chemistry, physical, materials, biology and interdisciplinary science have been in full flow in the past decade. In this Feature Article, recent developments in preparation of GQDs are discussed, focusing on the main two approaches (top-down and bottom-down). Emphasis is given to their future and potential development in bioimaging, electrochemical biosensors and catalysis, and specifically in photovoltaic devices that can solve increasingly serious energy problems.
Co-reporter:Xin Jiang, Xiaoling Yang, Yihua Zhu, Hongliang Jiang, Yifan Yao, Peng Zhao and Chunzhong Li
Journal of Materials Chemistry A 2014 - vol. 2(Issue 29) pp:NaN11133-11133
Publication Date(Web):2014/05/08
DOI:10.1039/C4TA01348D
A three-dimensional (3D) foam architecture of ultrafine TiO2 nanoparticles embedded in N-doped graphene networks (denoted as UTO/NGF) is prepared via a facile hydrothermal self-assembly and a subsequent freeze-drying scheme. The obtained UTO/NGF possesses a large surface area, macro/mesoporous structure, and high-level nitrogen content (7.34%). Such a unique hierarchical architecture provides multidimensional electronic network, enlarged contact area between electrolyte and electrode, and numerous open channels for the access of the electrolyte, thus favoring diffusion kinetics for both electrons and lithium ions. Meanwhile, nitrogen doping can further improve the electrical conductivity and electrochemical activity of the obtained composite during electrochemical processes. As a consequence, the UTO/NGF exhibits high reversible capacities with remarkable cyclic retention at different current rates (165 mA h g−1 after 200 cycles at 1 C rate, 143 mA h g−1 after 200 cycles at 5 C rate) and excellent rate performance (96 mA h g−1 at 20 C) as anodes in lithium ion batteries.
Co-reporter:Hongliang Jiang, Yunhe Su, Yihua Zhu, Jianhua Shen, Xiaoling Yang, Qian Feng and Chunzhong Li
Journal of Materials Chemistry A 2013 - vol. 1(Issue 39) pp:NaN12081-12081
Publication Date(Web):2013/08/08
DOI:10.1039/C3TA12493B
Three-dimensional (3D) hierarchical porous Co-containing N-doped carbon materials (HP-Co-CNs) have been successfully prepared for the first time by using cyanamide as a nitrogen source and poly(vinyl alcohol) (PVA) hydrogel-based composites as in situ templates. Remarkably, the resulting HP-Co-CNs possess controllable nitrogen content, high surface area, hierarchical interconnected macro-/mesoporous structure, and a certain amount of Co-Nx moieties which could act as active sites in the oxygen reduction reaction (ORR). In studying the application of HP-Co-CNs for the ORR, the HP-Co-CNs showed excellent electrocatalytic performance for a four-electron ORR, and longer-term stability and higher methanol tolerance then the commercial Pt/C electrocatalyst in alkaline medium, highlighting the importance of macropores for diffusion and a sufficient amount of active sites related to high specific surface area for improving the ORR performance.
Co-reporter:Xin Jiang, Xiaoling Yang, Yihua Zhu, Yifan Yao, Peng Zhao and Chunzhong Li
Journal of Materials Chemistry A 2015 - vol. 3(Issue 5) pp:NaN2369-2369
Publication Date(Web):2014/12/05
DOI:10.1039/C4TA05913A
A novel hierarchical nanostructure composed of carbon coated Fe3O4 nanoparticles with seed-like morphology distributed on graphene (denoted as G/Fe3O4@C) is prepared as a high-capacity anode electrode for LIBs. β-FeOOH nanoseeds were first assembled on graphene by solvothermal treatment, followed by coating β-FeOOH nanoseeds with polydopamine via immersion in dopamine aqueous solution. Finally, G/Fe3O4@C is obtained after in situ phase transformation of β-FeOOH into Fe3O4 and simultaneous carbonization of the polydopamine nanocoating through thermal annealing at 500 °C. The thickness of the uniform and continuous carbon layer can be easily tailored by varying the polymerization time and the concentration of dopamine to balance the concurrent needs for high active material content and structural stability. The carbon layer can effectively prevent the agglomeration of Fe3O4 nanoparticles, which enables the reversible conversion reaction between Fe3O4 and lithium, and significantly improves the mechanical stability of electrodes by accommodating volume expansion of Fe3O4 nanoparticles during the electrochemical cycling. Meanwhile, the combination of graphene and the carbon shell improves the electrochemical reaction kinetics of the electrode. As a result, the obtained G/Fe3O4@C nanocomposites with the optimal carbon shell thickness of about 1.2 nm exhibit high reversible capacities with remarkable cyclic retention at different current rates (1344 mA h g−1 after cycling at 0.5 C for 200 cycles, 743 mA h g−1 after further cycling at 2 C for another 200 cycles) and excellent rate performance (150 mA h g−1 at 20 C) as anodes in lithium ion batteries.
Co-reporter:Shunan Zhao, Jianfei Huang, Yanyan Liu, Jianhua Shen, Hao Wang, Xiaoling Yang, Yihua Zhu and Chunzhong Li
Journal of Materials Chemistry A 2017 - vol. 5(Issue 8) pp:NaN4214-4214
Publication Date(Web):2017/01/23
DOI:10.1039/C6TA10749D
In this study, excellent full water splitting achieved with a rationally structured multimetallic Ni–Mo/Cu nanowire free-standing electrode prepared via scalable electrochemistry is reported. By combining a conductive nanostructured scaffold and highly active outer layers, the as-prepared Ni–Mo/Cu nanowires deliver superior hydrogen and oxygen evolution performance. To achieve a 20 mA cm−2 catalytic current in a 1 M KOH electrolyte, the NM-CNW requires an overpotential of only 152 mV for hydrogen evolution and 280 mV for oxygen evolution. When assembled into a full electrolyzer, the Ni–Mo/Cu nanowires can drive full water splitting at nearly 100% faradaic efficiency steadily up to 12 h without any significant performance decay, and afford a catalytic current close to that of the state-of-the-art Pt–RuO2 system over long-term operation.
Co-reporter:Jianhua Shen, Yihua Zhu, Xiaoling Yang and Chunzhong Li
Journal of Materials Chemistry A 2012 - vol. 22(Issue 26) pp:NaN13347-13347
Publication Date(Web):2012/05/16
DOI:10.1039/C2JM31998E
We have demonstrated a sandwich-structured Fe3O4/SiO2/Au/TiO2 photocatalyst, which shows magnetic separability, selective absorption and photocatalysis activity, and high efficiency, in catalyzing the decomposition of organic compounds under illumination of visible-light and simulated sunlight. The structural design of the photocatalyst takes advantage of the dense, homogeneous structure and the AuNPs content (ca. 4 nm, 1.63 wt%), which is prepared by a simple method. It possesses high efficiency visible-light photocatalytic activity due to the stable from nonmetal-doping and the plasmonic metal decoration, which enhances light harvesting and charge separation, and the small grain size of the anatase nanocrystals, which reduces the exciton recombination rate. More importantly, the catalyst is synthesized by a combination of plasmonic metal decoration of TiO2 nanocrystals with exposed {001} facets, and the selective adsorption and photocatalytic decomposition of azo dyes is accomplished by design of the surface chemistry. Additionally, these sandwich-structured photocatalysts can be applied to other catalytic system such as dye decoloration, water decomposition, hydrogen generation, and so on.
Co-reporter:Xiaoming Lv, Yihua Zhu, Hongliang Jiang, Hua Zhong, Xiaoling Yang and Chunzhong Li
Dalton Transactions 2014 - vol. 43(Issue 40) pp:NaN15118-15118
Publication Date(Web):2014/08/13
DOI:10.1039/C4DT02245A
A novel and facile strategy has been successfully developed to synthesize uniform gold@titanium dioxide octahedral nanocages (Au@TiO2), which have a well-defined double-shelled structure with Au as the internal shell and TiO2 as the external shell. The unique Au@TiO2 double-shelled octahedral nanocages were elaborately fabricated by a Cu2O-templated strategy combining with spatially confined galvanic replacement. The formation process of these delicate hierarchical octahedral architectures is discussed in detail. The catalytic performance of the Au@TiO2 double-shelled octahedral nanocages was investigated using the reduction of 4-nitrophenol as a model reaction. The mesoporous structure of both the Au and TiO2 shells provides direct access for the reactant molecules to diffuse and subsequently interact with the Au shell. This novel catalyst shows excellent and stable activity for the catalytic reduction of 4-nitrophenol, which can be recycled for ten successive cycles of the reaction with a conversion efficiency of more than 90%. The superior catalytic activity attributes to mesoporous double shells, enhanced synergistic effects between the Au and TiO2 shells and the unique properties of the octahedral structure. More importantly, the as-obtained Au@TiO2 double-shelled octahedral nanocages also show potential applications in solar cells, organocatalysis and water splitting.
Co-reporter:Jie Zong, Yihua Zhu, Xiaoling Yang, Jianhua Shen and Chunzhong Li
Chemical Communications 2011 - vol. 47(Issue 2) pp:NaN766-766
Publication Date(Web):2010/11/10
DOI:10.1039/C0CC03092A
A novel and facile approach for preparing hydrophilic carbogenic dots (CDs) has been developed with mesoporous silica spheres as nanoreactors by using an impregnation method. The resulting highly efficient photoluminescent CDs without any further treatment are monodisperse, photostable and of low toxicity, and show excellent luminescence properties.
Co-reporter:Yanyan Liu, Hongliang Jiang, Yihua Zhu, Xiaoling Yang and Chunzhong Li
Journal of Materials Chemistry A 2016 - vol. 4(Issue 5) pp:NaN1701-1701
Publication Date(Web):2016/01/06
DOI:10.1039/C5TA10551J
The development of efficient and cheap bifunctional oxygen electrocatalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) to be applied in rechargeable metal–air batteries and unitized generative fuel cells (URFCs) operated with alkaline electrolytes is highly crucial and challenging. Here we report high-performance bifunctional electrocatalysts of transition metal nanoparticles encapsulated in nitrogen-doped carbon nanotubes (M/N-CNTs, M = Fe, Co, and Ni). The optimized Co/N-CNT hybrid shows the highest efficient bifunctional catalytic activity and excellent stability towards both the ORR and OER. The oxygen electrode activity parameter ΔE (the criteria for judging the overall catalytic activity of bifunctional electrocatalysts) value for Co/N-CNTs is 0.78 V, which surpasses those of Pt/C and RuO2 catalysts and most of the non-precious metal based bifunctional electrocatalysts reported in the previous literature studies. Furthermore, excellent long-term catalytic durability holds great promise in fields of renewable energy applications.
Co-reporter:Xiaoming Lv, Yihua Zhu, Hongliang Jiang, Xiaoling Yang, Yanyan Liu, Yunhe Su, Jianfei Huang, Yifan Yao and Chunzhong Li
Dalton Transactions 2015 - vol. 44(Issue 9) pp:NaN4154-4154
Publication Date(Web):2015/01/19
DOI:10.1039/C4DT03803G
The design and fabrication of efficient and inexpensive electrodes for oxygen evolution reaction (OER) is essential for energy-conversion technologies. Herein, high OER activity is achieved using hollow mesoporous NiCo2O4 nanocages synthesized via a Cu2O-templated strategy combined with coordination reaction. The NiCo2O4 nanostructures with a hollow cavity, large roughness and high porosity show only a small overpotential of ∼0.34 V at the current density of 10 mA cm−2 and a Tafel slope of 75 mV per decade, which is comparable with the performance of the best reported transition metal oxide based OER catalysts in the literature. Meanwhile, the positive impacts of the nanocage structure and the Ni incorporation on the electrocatalytic performance are also demonstrated by comparing the OER activities of NiCo2O4 nanocages with Co3O4 nanocages, NiCo2O4 nanoparticles and 20 wt% Pt/C. Moreover, the NiCo2O4 nanocages also manifest superior stability to other materials. All these merits indicate that the hollow mesoporous NiCo2O4 nanocages are promising electrocatalysts for water oxidation.
