Co-reporter:Zifei Wang;Fanglong Yuan;Xiaohong Li;Yunchao Li;Haizheng Zhong;Shihe Yang
Advanced Materials 2017 Volume 29(Issue 37) pp:
Publication Date(Web):2017/10/01
DOI:10.1002/adma.201702910
Red emissive carbon quantum dots (R-CQDs) with quantum yield of 53% is successfully prepared. An ultraviolet (UV)-pumped CQD phosphors-based warm white light-emitting diode (WLED) is realized for the first time and achieves a color rendering index of 97. This work provides a new avenue for the exploration of low cost, environment-friendly, and high-performance CQD phosphors-based warm WLEDs.
Co-reporter:Zetan Fan;Shixin Zhou;Cesar Garcia;Jiangbing Zhou
Nanoscale (2009-Present) 2017 vol. 9(Issue 15) pp:4928-4933
Publication Date(Web):2017/04/13
DOI:10.1039/C7NR00888K
Cancer remains a major cause of morbidity and mortality around the world. Improved cancer treatment requires enhancement of cancer diagnosis and detection. To achieve this goal, here we report a novel imaging probe, pH-responsive fluorescent graphene quantum dots (pRF-GQDs). pRF-GQDs were prepared by electrolysis of graphite rods in sodium p-toluenesulfonate acetonitrile solution. The resulting pRF-GQDs, which have minimal toxicity, display a sharp fluorescence transition between green and blue at pH 6.8, a pH matching the acidic extracellular microenvironment in solid tumors. We found that this unique fluorescence switch property allows tumors to be distinguished from normal tissues. In addition to fluorescence, pRF-GQDs also exhibit upconversion photoluminescence (UCPL). We demonstrate that the combination of UCPL and fluorescence switch enables detection of solid tumors of different origin at an early developmental stage. Therefore, pRF-GQDs have great potential to be used as a universal probe for fluorescence-guided cancer surgery and cancer diagnosis.
Co-reporter:Lirui Nan, Zetan Fan, Wenbo Yue, Qiao Dong, Lisha Zhu, Liu Yang and Louzhen Fan
Journal of Materials Chemistry A 2016 vol. 4(Issue 22) pp:8898-8904
Publication Date(Web):12 May 2016
DOI:10.1039/C6TA01416J
Noble metal Pd is usually regarded as a promising electrode material for fuel cells due to its high electrocatalytic activity, abundance and greater resistance to CO poisoning. Moreover, the electrocatalytic performance of Pd can be further improved by using novel carbon materials as supports or metal oxides as catalyst promoters. In this work, Pd nanoparticles with a trace of SnO2 are synthesized and anchored on a novel graphene-based porous carbon (G-mC) support by using a modified electroless plating technique. The two-dimensional (2D) porous carbon film on the graphene can separate Pd nanoparticles and limit their growth (<3 nm), while the graphene substrate can enhance the electronic conductivity of the composite. In addition, SnO2 nanoparticles around Pd catalysts may prevent CO poisoning at the catalytic sites, which is beneficial to improving the electrocatalytic performance of Pd catalysts. Therefore, compared to porous carbon (CMK-3) supported Pd catalysts with SnO2 or G-mC supported Pd catalysts without SnO2, G-mC supported Pd catalysts with SnO2 show enhanced electrocatalytic activity and durability for methanol oxidation. In particular, the electrocatalytic activity retention of the composite is maintained at ∼85% after 500 cycles. This novel 2D carbon support is expected to be applied in batteries, supercapacitors or fuel cells.
Co-reporter:Rongbin Xie, Zifei Wang, Hongtao Yu, Zetan Fan, Fanglong Yuan, Yunchao Li, Xiaohong Li, Louzhen Fan, Hong Fan
Electrochimica Acta 2016 Volume 201() pp:220-227
Publication Date(Web):20 May 2016
DOI:10.1016/j.electacta.2016.03.198
Water-soluble and surface charge-tunable amine-functionalized polyhydroxylated fullerene nanoparticles with a strong green emission were synthesized by grinding and hydrothermal treatment. The quantum yield of the nanoparticles was as high as 17%, which is the highest value recorded for fluorescent fullerene materials. The amine-functionalized polyhydroxylated fullerene nanoparticles with high surface charge were found to easily penetrate into breast cancer cells, HeLa cells and cardiac progenitor stem cells, opening up great opportunities for their bio-medical applications.
Co-reporter:Yanting Liu;Shixin Zhou;Hong Fan
Microchimica Acta 2016 Volume 183( Issue 9) pp:2605-2613
Publication Date(Web):2016 September
DOI:10.1007/s00604-016-1909-1
We have prepared graphene quantum dot-europium(III) complex composites by noncovalently connecting chelating ligands dibenzoylmethane (DBM) and 1,10-phenanthroline (Phen) with graphene quantum dots (GQDs) first, followed by coordination to Eu(III). The resulting composites are well water-soluble and display red fluorescence of high color purity. The composites were characterized by transmission electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction. Aqueous solutions of the composites under 365 nm excitation display fluorescence with a peak at 613 nm and a quantum yield as high as 15.5 %. The good water solubility and stable photoluminescence make the composites very different from other Eu(III)-based coordination complexes. The composites are cell viable and can be used to label both the cell membrane and the cytoplasm of MCF-7 cells. They are also shown to act as bioprobes for in-vivo localization of tumorous tissue. In our perception, such composites are expected to possess wide scope because of the many functionalizations that are possible with GQDs.
Co-reporter:Fanglong Yuan, Shuhua Li, Zetan Fan, Xiangyue Meng, Louzhen Fan, Shihe Yang
Nano Today 2016 Volume 11(Issue 5) pp:565-586
Publication Date(Web):October 2016
DOI:10.1016/j.nantod.2016.08.006
•An overview on the synthesis, structure, optical and electronic properties of CDs are summarized.•The mechanisms of the tunable PL properties of CDs are discussed and summarized.•Recent progress of CDs for biomedical and optoelectronic applications are reviewed.•The current challenges and new perspectives which project directions of the research of CDs are proposed.In recent years, the emerging fluorescent carbon dots have shown enormous potentials for biomedical and optoelectronic applications owing to their outstanding characteristics such as good biocompatibility, low cytotoxicity, photostability and versatility in addition to their unique tunable photoluminescence and other exceptional physicochemical properties. In this review, we will update the latest researches on the synthesis, structure, optical and electronic properties of CDs as well as their advanced applications in biomedicine and optoelectronics. We will mainly discuss the applications of CDs in bioimaging with emphasis on stem cells imaging including normal and cancer stem cells, cell nucleus imaging, two-photon fluorescence imaging, red or near-infrared emission for in vivo imaging, cancer therapy including photodynamic therapy, photothermal therapy and chemotherapy, and optoelectronic applications including light emitting diodes and solar energy conversion. Finally, we will size up current challenges on the research of CDs and project future directions of the field. We hope that this review will provide critical insights to inspire new exciting discoveries on CDs from both fundamental and practical standpoints so that the realization of their potential in the biomedical and optoelectronic areas can be facilitated.
Co-reporter:Fanglong Yuan, Ling Ding, Yunchao Li, Xiaohong Li, Louzhen Fan, Shixin Zhou, Decai Fang and Shihe Yang
Nanoscale 2015 vol. 7(Issue 27) pp:11727-11733
Publication Date(Web):08 Jun 2015
DOI:10.1039/C5NR02007G
Smart functional nanomaterials colorimetrically responsive to all-pH and a wide temperature range are urgently needed due to their widespread applications in biotechnology, drug delivery, diagnosis and optical sensing. Although graphene quantum dots possess remarkable advantages in biological applications, they are only stable in neutral or weak acidic solutions, and strong acidic or alkaline conditions invariably suppress or diminish the fluorescence intensity. Herein, we report a new type of water-soluble, multicolor fluorescent graphene quantum dot which is responsive to all-pH from 1 to 14 with the naked eye. The synthesis was accomplished by electrolysis of the graphite rod, followed by refluxing in a concentrated nitric and sulfuric acid mixed solution. We demonstrate the novel red fluorescence of quinone structures transformed from the lactone structures under strong alkaline conditions. The fluorescence of the resulting graphene quantum dots was also found to be responsive to the temperature changes, demonstrating their great potential as a dual probe of pH and temperature in complicated environments such as biological media.
Co-reporter:Xiaoyun Tan, Yunchao Li, Xiaohong Li, Shixin Zhou, Louzhen Fan and Shihe Yang
Chemical Communications 2015 vol. 51(Issue 13) pp:2544-2546
Publication Date(Web):08 Jan 2015
DOI:10.1039/C4CC09332A
We report water-soluble, 3 nm uniform-sized graphene quantum dots (GQDs) with red emission prepared by electrochemical exfoliation of graphite in K2S2O8 solution. Such GQDs show a great potential as biological labels for cellular imaging.
Co-reporter:Ruihua Guo, Shixin Zhou, Yunchao Li, Xiaohong Li, Louzhen Fan, and Nicolas H. Voelcker
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 43) pp:23958
Publication Date(Web):August 28, 2015
DOI:10.1021/acsami.5b06523
A turn-on orange-red fluorescent nanosensor based on rhodamine B derivative-functionalized graphene quantum dots (RBD-GQDs) has been successfully synthesized for Fe3+ detection with high sensitivity and selectivity. By connecting with GQDs, the water solubility, sensitivity, photostability, and biocompatibility of RBD are drastically improved. The most distinctive feature of the RBD-GQDs, which sets them apart from other previously reported fluorophores or GQDs, is that they with the detection limits as low as 0.02 μM are demonstrated as a Fe3+ turn-on fluorescent nanosensor in cancer stem cells. Fe3+ binding to such GQDs (RBD-GQDs-Fe3+) with orange-red fluorescence of 43% quantum yield were demonstrated to be the biomarkers for cancer stem cell imaging.Keywords: cancer stem cells; detection; Fe3+; graphene quantum dots; rhodamine B derivative
Co-reporter:Zetan Fan, Shuhua Li, Fanglong Yuan and Louzhen Fan
RSC Advances 2015 vol. 5(Issue 25) pp:19773-19789
Publication Date(Web):06 Feb 2015
DOI:10.1039/C4RA17131D
Fluorescent carbon-based nanomaterials, including carbon dots (C-Dots) and the emerging graphene quantum dots (GQDs) are attracting increasing interest in the field of biosensing and bioimaging for their high aqueous solubility, stable photoluminescence (PL), low cytotoxicity, good biocompatibility as well as superior resistance to photobleaching. Compared with C-Dots, the quasi zero-dimensional (0D) GQDs with a few atomic layers can exhibit strong PL without passivation. With these extraordinary properties, GQDs are suitable alternatives as both a versatile platform for biosensing and a promising class of bioimaging probes. In this review, we introduce the synthesis, structure, PL properties and currently available applications of GQDs in biosensing and bioimaging field. We hope this review will provide critical insights to inspire more exciting researches on GQDs for biological applications to better realize the potential of the intriguing GQDs in the near future.
Co-reporter:Shuhua Li;Ling Ding
Science China Chemistry 2015 Volume 58( Issue 3) pp:417-424
Publication Date(Web):2015 March
DOI:10.1007/s11426-015-5319-8
Sulfur (S)-doped graphene sheets were prepared by a facile electrochemical method, which effectively combined exfoliation of graphite and in situ S doping of graphene together. The metal-free S-doped graphene sheets exhibit high electrocatalytic activity, long-term stability, and excellent tolerance to cross-over effects of methanol in alkaline media for the oxygen reduction reaction (ORR), indicating that these S-doped graphene sheets possess great potential for a substitute for Pt-based catalysts in fuel cells.
Co-reporter:Zonglong Zhu ; Jiani Ma ; Zilong Wang ; Cheng Mu ; Zetan Fan ; Lili Du ; Yang Bai ; Louzhen Fan ; He Yan ; David Lee Phillips ;Shihe Yang
Journal of the American Chemical Society 2014 Volume 136(Issue 10) pp:3760-3763
Publication Date(Web):February 24, 2014
DOI:10.1021/ja4132246
We report on a significant power conversion efficiency improvement of perovskite solar cells from 8.81% to 10.15% due to insertion of an ultrathin graphene quantum dots (GQDs) layer between perovskite and TiO2. A strong quenching of perovskite photoluminescence was observed at ∼760 nm upon the addition of the GQDs, which is pronouncedly correlated with the increase of the IPCE and the APCE of the respective cells. From the transient absorption measurements, the improved cell efficiency can be attributed to the much faster electron extraction with the presence of GQDs (90–106 ps) than without their presence (260–307 ps). This work highlights that GQDs can act as a superfast electron tunnel for optoelectronic devices.
Co-reporter:Weihu Shang, Xiaoyan Zhang, Mo Zhang, Zetan Fan, Ying Sun, Mei Han and Louzhen Fan
Nanoscale 2014 vol. 6(Issue 11) pp:5799-5806
Publication Date(Web):17 Apr 2014
DOI:10.1039/C3NR06433F
Cellular imaging after transplantation may provide important information to determine the efficacy of stem cell therapy. We have reported that graphene quantum dots (GQDs) are a type of robust biological labeling agent for stem cells that demonstrate little cytotoxicity. In this study, we examined the interactions of GQDs on human neural stem cells (hNSCs) with the aim to investigate the uptake and biocompatibility of GQDs. We examined the mechanism of GQD uptake by hNSCs and investigated the effects of GQDs on the proliferation, metabolic activity, and differentiation potential of hNSCs. This information is critical to assess the suitability of GQDs for stem cell tracking. Our results indicated that GQDs were taken up into hNSCs in a concentration- and time-dependent manner via the endocytosis mechanism. Furthermore, no significant change was found in the viability, proliferation, metabolic activity, and differentiation potential of hNSCs after treatment with GQDs. Thus, these data open a promising avenue for labeling stem cells with GQDs and also offer a potential opportunity to develop GQDs for biomedical applications.
Co-reporter:Hongtao Yu, Yunchao Li, Xiaohong Li, Louzhen Fan and Shihe Yang
Journal of Materials Chemistry A 2014 vol. 2(Issue 38) pp:15763-15767
Publication Date(Web):01 Sep 2014
DOI:10.1039/C4TA03476G
The surface charge-tunable Fe3O4 nanoparticles with high dispersibility and high superparamagnetism are fabricated by a facile electrochemical method in acetonitrile. These nanoparticles can reversibly bind to graphene oxides, which could be recycled and continually used for high-efficient removal of dye pollutants from water.
Co-reporter:Zetan Fan, Yunchao Li, Xiaohong Li, Louzhen Fan, Shixin Zhou, Decai Fang, Shihe Yang
Carbon 2014 70() pp: 149-156
Publication Date(Web):
DOI:10.1016/j.carbon.2013.12.085
Co-reporter:Hongtao Yu; Yunchao Li; Xiaohong Li; Louzhen Fan; Shihe Yang
Chemistry - A European Journal 2014 Volume 20( Issue 12) pp:3457-3462
Publication Date(Web):
DOI:10.1002/chem.201303814
Abstract
Nitrogen-doped CoO (N-CoO) nanoparticles with high electrocatalytic activity for the oxygen-reduction reaction (ORR) were fabricated by electrochemical reduction of CoCl2 in acetonitrile solution at cathodic potentials. The initially generated, highly reactive nitrogen-doped Co nanoparticles were readily oxidized to N-CoO nanoparticles in air. In contrast to their N-free counterparts (CoO or Co3O4), N-CoO nanoparticles with a N content of about 4.6 % exhibit remarkable ORR electrocatalytic activity, stability, and immunity to methanol crossover in an alkaline medium. The CoNx active sites in the CoO nanoparticles are held responsible for the high ORR activity. This work opens a new path for the preparation of nitrogen-doped transition metal oxide nanomaterials, which are promising electrocatalysts for fuel cells.
Co-reporter:Ling Ding, Yifeng E, Louzhen Fan and Shihe Yang
Chemical Communications 2013 vol. 49(Issue 56) pp:6286-6288
Publication Date(Web):23 May 2013
DOI:10.1039/C3CC42773K
We report a unique strategy for efficiently exfoliating large size and high quality single-layer graphene directly from graphite into DMF dispersions by growing ZnO nanorod arrays between the graphene layers in graphite.
Co-reporter:Lina Gao, Ling Ding, Louzhen Fan
Electrochimica Acta 2013 Volume 106() pp:159-164
Publication Date(Web):1 September 2013
DOI:10.1016/j.electacta.2013.05.065
Pt nanoflowers (NFs) with uniform size and high dispersion have been inserted between sheets of graphene through a three-step protocol consisting of ZnO nanoparticle (NP) expansion of graphite, electrochemical deposition of PtCl62−, and dissolution of the ZnO NPs. The key synthesis strategy employs ZnO NPs as the insertion to increase the graphite interlayer distance for insertion of PtCl62− but avoid the preparation of graphene oxides (GOs) and further reduction processes. The resulting Pt NF/graphene-layered composites are characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD) and Raman spectra. The results show that highly dispersed Pt NFs with a uniform size of 250 nm insert between the graphene sheets and exhibit significantly higher electrocatalytic activity and better stability for the oxidation of methanol compared to Pt NFs deposited on the surface of graphite and GOs. These attractive features are a result of the layered structure consisting of alternating highly dispersed Pt NFs with high surface area and graphene with high conductivity. Our work provides a new route for the preparation of Pt NF/graphene-layered composites, which are promising electrocatalysts for direct methanol fuel cells.
Co-reporter:Chenxing Zhao, Hongtao Yu, Yunchao Li, Xiaohong Li, Ling Ding, Louzhen Fan
Journal of Electroanalytical Chemistry 2013 Volume 688() pp:269-274
Publication Date(Web):1 January 2013
DOI:10.1016/j.jelechem.2012.08.032
A novel template-assisted deposition and etching strategy is proposed in this paper for preparing IrO2 nanotube arrays on ITO substrates, i.e., electrodepositing IrO2 nanoparticles onto ZnO nanorod surfaces to produce IrO2-coated core–shell nanorod arrays, and followed by wet chemical etching the ZnO nanorods away to generate IrO2 nanotube arrays. Well-aligned IrO2 nanotube arrays with high purity and uniform size are produced by using this synthetic strategy. Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) are employed to examine the morphology, fine structure and composition of the IrO2 nanotube arrays intensively. Furthermore, electrocatalytic water oxidization experiments are performed to assess the catalytic performance of the as-prepared IrO2 nanotube arrays toward oxygen evolution reaction (OER). The IrO2 nanotube arrays have been found to possess an excellent catalytic performance: high turnover frequency (3.3 s−1 for TOF at 1.2 V versus Ag/AgCl), low oxygen evolution overpotential (η = 0.15 V) and good catalytic stability (55% catalytic activity remaining after undergoing 400 times potential cycles).Graphical abstractWell-aligned IrO2 nanotube arrays are fabricated by using a template-assisted deposition and etching strategy, which demonstrates good catalytic performance toward oxygen evolution reaction (OER).Highlights► A simple an general strategy for fabricating nanotube arrays. ► Well-aligned IrO2 nanotube arrays on conductive substrates. ► Excellent catalytic performance toward oxygen evolution reaction (OER).
Co-reporter:Lina Gao, Wenbo Yue, Shanshan Tao, and Louzhen Fan
Langmuir 2013 Volume 29(Issue 3) pp:957-964
Publication Date(Web):December 21, 2012
DOI:10.1021/la303663x
As advanced electrodes for direct alcohol fuel cells, graphene-Pd and graphene-Pt composites with a trace of SnO2 have been successfully synthesized by a modified electroless plating technique. The surface of graphene oxide is first sensitized by Sn2+ ions, and subsequently, Pd or Pt nanoparticles are deposited on the surface of graphene oxide. Finally, graphene oxide was reduced to graphene by further adding NaBH4. Compared to other carbon-(e.g., Vulcan XC-72R) supported Pd and Pt, the resultant graphene-Pd and Pt composites exhibit better electrocatalytic activity and long-term stability toward alcohol electrooxidation. Additionally, a trace amount of SnO2 formed around active catalysts may also be beneficial to the enhancement of electrochemical activity.
Co-reporter:Chenxing Zhao;Yifeng E.
Microchimica Acta 2012 Volume 178( Issue 1-2) pp:107-114
Publication Date(Web):2012 July
DOI:10.1007/s00604-012-0818-1
We report on the synthesis of a composite made from iridium oxide and gold that has a flower-like morphology. The ratio of iridium oxide to gold can be controlled by altering the concentrations of the metal precursors or the pH of the solution containing the reductant citrate. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and laser confocal micro-Raman spectroscopy were applied to characterize the structures of the nanoflowers, and a mechanism of their formation was deduced. The nanoflowers display an electrocatalytic activity in an oxygen evolution reaction (OER) that is significantly enhanced compared to bare iridium oxide nanoparticles. The highest turnover frequency for the OER of the new nanoflowers is 10.9 s−1, which is almost one order of magnitude better than that of the respective nanoparticles. These attractive features are attributed to the high oxidation states of iridium in the nanoflowers which is caused by the transfer of electronic charge from metal oxides to gold, and also to the flower fractal structure which is thought to provide a much more accessible surface than suspensions of the respective nanoparticle.
Co-reporter:Liqing Li, Yifeng E, Jumao Yuan, Xiayue Luo, Yang Yang, Louzhen Fan
Electrochimica Acta 2011 Volume 56(Issue 17) pp:6237-6244
Publication Date(Web):1 July 2011
DOI:10.1016/j.electacta.2011.02.096
Pd/Au hollow cone-like microstructures (HCMs) have been electrodeposited on indium tin oxide (ITO) using a two-step protocol, which involves the nucleation pulse and succedent constant potential reduction in the presence of metal precursors and polyvinylpyrrolidone (PVP). Scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscope (XPS) were used to characterize the Pd/Au HCMs. The electrochemical results (cyclic voltammetry and chronoamperometry) testify that the Pd/Au HCMs exhibit significantly higher electrocatalytic activity and stability for the oxidation of formic acid than that of Pd/Au solid microhemispheres (SMHs). These attractive features are attributable to the unique hollow structures of Pd/Au with much higher electrochemical active surface areas and the exposure of favorable planes. Our work points to a new path for the preparation of Pd/Au HCMs, which are promising as electrocatalysts in direct formic acid fuel cell (DFAFC).
Co-reporter:Dr. Yang Zhang;Dr. Lang Jiang;Hui Li; Louzhen Fan; Wenping Hu;Chunru Wang;Yongfang Li; Shihe Yang
Chemistry - A European Journal 2011 Volume 17( Issue 17) pp:4921-4926
Publication Date(Web):
DOI:10.1002/chem.201002719
Abstract
Large-scale single-crystalline hollow nanobowls of pure C60 were prepared by applying a sonophysical strategy in a binary organic solution. Through the simple adjustment of the concentration of the C60/m-xylene solution and the volume ratio of m-xylene to acetonitrile, C60 nanorings, nanoplates, nanorods, and nanowires were also selectively synthesized. The promise of the C60 hollow structures as Pt catalyst supports is heightened by the significantly enhanced catalytic activity toward methanol oxidation for a given amount of C60 used, which demonstrates their potential application in fuel cells.
Co-reporter:Yang Zhang, Wei Liu, Lang Jiang, Louzhen Fan, Chunru Wang, Wenping Hu, Haizheng Zhong, Yongfang Li and Shihe Yang
Journal of Materials Chemistry A 2010 vol. 20(Issue 5) pp:953-956
Publication Date(Web):09 Dec 2009
DOI:10.1039/B913897H
Crystal orientation-ordered C60 nanorod bundles have been assembled, where each C60 nanorod maintains its individual shape and identity with unpolymerized bucky balls and all of the nanorods are vertically aligned with a high density. The key to this lies in the assembly of the C60 nanorod bundles from the nanoscopic to microscopic and macroscopic scale. The novel structure of C60 nanorod bundles leads to a high photoresponse, which is promising for applications in optical devices.
Co-reporter:Weiling Guo, Yifeng E, li Gao, Louzhen Fan and Shihe Yang
Chemical Communications 2010 vol. 46(Issue 8) pp:1290-1292
Publication Date(Web):14 Jan 2010
DOI:10.1039/B919370G
We report the first novel cathodic electrochemiluminescence of Ru(bpy)32+ at positive potential of +0.6 V (vs. Ag/AgCl) with a strong light emission clearly visible to the naked eye triggered by reactive oxygen species O2˙− on an in situ electrodeposited Co3O4 nanostructured electrode.
Co-reporter:Xiaomo Zhou, Louzhen Fan
Electrochimica Acta 2010 Volume 55(Issue 27) pp:8111-8115
Publication Date(Web):30 November 2010
DOI:10.1016/j.electacta.2010.02.023
Bowl-like nanostructures of Pt/Pd bimetallic nanocrystals are prepared by employing Ag nanoparticles as a template and completely removing the residual Ag after the displacement. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations display that the thin walls of Pt/Pd nanobowls are composed of nanoparticles. X-ray diffraction (XRD) pattern demonstrates that Pt and Pd form the alloy in the nanobowls. The crystal structures of the nanobowls consist of [1 1 1], [2 0 0], [2 2 0] surfaces as revealed by both high-resolution TEM (HRTEM) and XRD results. The Pt/Pd nanobowls exhibit significant high electrocatalytic activities toward the methanol oxidation and oxygen reduction compared with the Pt/Pd nanospheres and Pt nanobowls.
Co-reporter:Changzheng Wang, Yifeng E, Louzhen Fan, Shihe Yang and Yongliang Li
Journal of Materials Chemistry A 2009 vol. 19(Issue 23) pp:3841-3846
Publication Date(Web):31 Mar 2009
DOI:10.1039/B821213A
CdS-Ag nanocomposite arrays were successfully prepared by the electrochemical approach based on CdS hierarchical nano-arrays as templates. The optical signatures, including UV-vis absorption, photoluminescence (PL), Raman, and electro-chemiluminescence (ECL), of the CdS-Ag nanocomposite arrays and hierarchical CdS nano-arrays are spectrally distinct, allowing strong coupling between CdS and Ag. A novel hydrogen peroxide ECL sensor based on the CdS-Ag nanocomposite arrays fabricated with our unique assembling strategy has a low detection limit of 1.5 × 10−8 M.
Co-reporter:Li Gao, Louzhen Fan and Jian Zhang
Langmuir 2009 Volume 25(Issue 19) pp:11844-11848
Publication Date(Web):July 30, 2009
DOI:10.1021/la901490w
A new type of bimetallic Au−Ag heterostructured material was prepared by a selective growing strategy of a Ag nanodewdrop on the petal tip of a Au flower using an electrochemical method. The whole process was strictly controlled by forming the reactive tip of the flower petal and passivating the facet along the body of the metal petal using poly(vinyl pyrrolidone) (PVP) coating film. The formed Au−Ag heterostructured flowers (HSFs) were observed to be about 2 μm in diameter and have the Ag particles of about 50 nm settled on the tips of Au petals. The Au−Ag HSFs were found to display the superior properties on the surface-enhanced Raman scattering (SERS). The presence of Ag nanodewdrops could also facilitate the oxidation of Ru(bpy)32+ complex in electrogenerated chemiluminescence (ECL) measurements and dramatically enhance the emission intensity. The features of Au−Ag HSFs can promise a new type of heterogeneous bimetallic alloy material for the potential applications in chemical and biological sensors.
Co-reporter:Mingyan Zhao;Lin Zhang;Ning Chen;Chunru Wang
Microchimica Acta 2009 Volume 165( Issue 1-2) pp:45-52
Publication Date(Web):2009 April
DOI:10.1007/s00604-008-0095-1
The electrochemical behavior of trimetallic nitride clusterfullerene (Sc3N@C78) embedded in films of the cationic surfactant didodecyldimethylammonium bromide (DDAB) on glassy carbon (GC) electrodes in aqueous solution was investigated. Four pairs of reversible redox peaks were observed in the potential range between +0.6 and −0.9 V vs. SCE. Different to the electrochemistry of pristine Sc3N@C78 in organic solution, the first reduction is a one-electron rather than simultaneous two-electron process because of the strong binding between DDA+ and the monoanion of Sc3N@C78. The generated radial monoanion, dianion and trianion of Sc3N@C78 are stable during continuous potential cycling, while some chemical reactions take place when the third anion is further reduced in the films. The cyclic voltammograms of Sc3N@C78/DDAB films checked at different temperatures pointed to strong temperature dependence. The electrochemical processes were also measured in different electrolytes, which showed pronounced anionic dependence and no cathodic dependence on either the cation or anions present. A possible electron-transfer mechanism of a Sc3N@C78/DDAB film was presented.
Co-reporter:Wei Wu Dr.;Huarui Zhu ;Shihe Yang
Chemistry - A European Journal 2008 Volume 14( Issue 19) pp:5981-5987
Publication Date(Web):
DOI:10.1002/chem.200701655
Abstract
A grapevine nanostructure based on single-walled carbon nanotubes (SWNTs) covalently functionalized with [60]fullerene (C60) has been synthesized and characterized in detail. Investigations into the ball-on-tube carbon nanostructure by ESR spectroscopy indicate a tendency for ground-state electron transfer from the SWNT to the C60 moieties. The cyclic-voltammetric response of the nanostructure film exhibits reversible multiple-step electrochemical reactions of the dispersed C60, which are strikingly similar to those of the C60 derivatives in solution, but with consistent negative shifts in the redox potential. This results from the covalent linkage of C60 to the surfaces of the SWNTs in the form of monomers and manifests the electronic interaction between the C60 and SWNT moieties.
Co-reporter:C. Z. Wang;Y. F. E;L. Z. Fan;Z. H. Wang;H. B. Liu;Y. L. Li;S. H. Yang;Y. L. Li
Advanced Materials 2007 Volume 19(Issue 21) pp:3677-3681
Publication Date(Web):23 OCT 2007
DOI:10.1002/adma.200701386
Hierarchical CdS nanotube arrays (see figure) are assembled in an anodic aluminum oxide template from CdS nanoparticles by using a controlled solution precipitation method. The hierarchical nanotube arrays, with high porosity and uniform alignment, display considerably varied photoluminescence and enhanced solid state electro-chemiluminescence in H2O2 solution compared with those of random nanoparticle aggregates.
Co-reporter:Y. Zhao;L. Fan;H. Zhong;Y. Li;S. Yang
Advanced Functional Materials 2007 Volume 17(Issue 9) pp:
Publication Date(Web):24 APR 2007
DOI:10.1002/adfm.200600416
3D flowerlike Pt nanoparticle clusters are electrodeposited onto multiwalled carbon nanotubes (MWCNTs) by using a three-step protocol, which is all-electrochemical and involves a key, second step of a potential pulse sequence. This 3D fractal morphology is in marked contrast to the 2D uniform nanoparticle dispersion of MWCNTs, which is achieved when the second step adopts cyclic voltammetry instead of a potential-step method. The former is found to exhibit significantly higher electrocatalytic activity and better stability than the latter for oxidation of methanol. These attractive features are attributable to the unique 3D flowerlike structure of Pt nanoparticle clusters on MWCNTs with much higher electrochemically active surface areas. Our work points to a new path for the preparation of 3D Pt/MWCNT nanocomposites, which are promising as electrocatalysts in direct methanol fuel cells.
Co-reporter:Yue Zhao, Yifeng E, Louzhen Fan, Yongfu Qiu, Shihe Yang
Electrochimica Acta 2007 Volume 52(Issue 19) pp:5873-5878
Publication Date(Web):25 May 2007
DOI:10.1016/j.electacta.2007.03.020
An electrochemical method was developed to deposit platinum (Pt) and nickel (Ni) nanoparticles on multi-walled carbon nanotubes (MWCNTs) through a three-step process. X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX) show the alloy formation for Pt and Ni with a ratio of 1:1. The presence of Pt(0), Ni(0), Ni(OH)2, NiOOH and slight NiO was deduced from XPS data. Electrocatalytic properties of the resulting PtNi/MWCNT electrode for methanol oxidation reaction were investigated. Compared with Pt/MWCNT, an appreciably improved resistance to CO poisoning was observed for the PtNi/MWCNT electrode, which was interpreted by a mechanism based on the bifunctional catalysis. The successful preparation of PtNi/MWCNT nanocomposites opens a new path for an efficient dispersion of the promising electrocatalysts in the direct methanol fuel cells.
Co-reporter:Lin Zhang, Ning Chen, Louzhen Fan, Chunru Wang, Shihe Yang
Journal of Electroanalytical Chemistry 2007 Volume 608(Issue 1) pp:15-21
Publication Date(Web):15 September 2007
DOI:10.1016/j.jelechem.2007.04.015
Electrochemical behavior of Sc3N@C78 solution was investigated for the first time by cyclic voltammetry (CV) as well as differential pulse voltammetry (DPV). Reversible redox features of Sc3N@C78 were obtained in contrast to that of Dy3N@C78, for which the corresponding redox waves were very recently found to be irreversible. Toluene/MeCN and four other solvents have been identified, wherewith reversible redox waves can also be observed for Sc3N@C80 (Ih) at a normal potential scan rate, whereas o-dichlorobenzene (o-DCB) was found to give only irreversible redox behavior as concluded by other researchers. The redox properties of Sc3N@C78 and Sc3N@C80 (Ih) are comparatively discussed on the basis of their different electronic structures and interactions with the solvent molecules. Additionally, electrochemical energy gaps of both Sc3N@C78 and Sc3N@C80 (Ih) were obtained.
Co-reporter:Yue Zhao;Haizheng Zhong;Yongfang Li
Microchimica Acta 2007 Volume 158( Issue 3-4) pp:327-334
Publication Date(Web):2007 May
DOI:10.1007/s00604-006-0701-z
Platinum (Pt) nanoparticles were electrochemically deposited on multi-walled carbon nanotubes (MWCNTs) through a three-step process, including an electrochemical treatment of MWCNT, electro-oxidation of PtCl42− to Pt(IV) complex, and an electro-conversion of Pt(0) on MWCNT. The effect of formation conditions for Pt(IV) complexes on the Pt nanoparticals transformed was investigated. The structure and elemental composition of the resulting Pt/MWCNT electrode were characterized by transmission electron micrograph (TEM) and energy dispersive X-ray spectroscopy (EDX). The electrocatalytic properties of the resulting Pt/MWCNT electrode for methanol oxidation have been investigated. The high electrocatalytic activity and good stability of Pt/MWCNT electrode may be attributed to the high dispersion of platinum nanoparticles and the particular properties of the MWCNT supports.
Co-reporter:H. Zhang;X. Huang;L. Z. Fan;B. Nin;Y. Q. Wu;L. P. Zheng;Y. Cao;B. Nin;Y. Cao;Y. Q. Wu;L. P. Zheng;X. Huang;H. Zhang;L. Z. Fan
Journal of Applied Polymer Science 2006 Volume 100(Issue 5) pp:3634-3640
Publication Date(Web):20 MAR 2006
DOI:10.1002/app.23156
Electrochemical properties of eight methanofullerene films, prepared on electrodes by casting, were examined by means of cyclic voltammetry and electrochemical quartz crystal microbalance (EQCM) technique in acetonitrile solution. Compared with C60 film, the film stability with respect to dissolution is associated with the length of the alkyl chains introduced into C60 cage and is strongly dependent on the nature of the cation of the supporting electrolyte. TBA+, Li+, K+, and Na+ were selected to observe the effect of countercations on the electrochemical behavior of methanofullerene films. In TBAPF6 solution, when short chains, such as formic ether or butyl butyrate groups, were introduced into C60 cage, the film stability was less than that of C60. When the length of the alkyl chain was extended to butyl 12 alkanoate group, the film would not dissolve until the third reduction process because the long alkyl chain could inflect and encase the cations into the film. In KPF6 or NaClO4 solution, however, the solubility of the salt formed by K+ or Na+ with methanofullerene anion was higher than that formed by TBA+ with methanofullerene anion. Li+ (alkali metal) affected the behavior of the films in different ways. The possible electron-transfer mechanisms of methanofullerene films in various supporting electrolyte solutions were presented. Furthermore, the film images observed by atomic force microscopy indicated that TBA+ and Li+ affected the behavior of the methanofullerene films in different ways. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3634–3640, 2006
Co-reporter:Hua Zhang Dr.;Shihe Yang
Chemistry - A European Journal 2006 Volume 12(Issue 27) pp:
Publication Date(Web):28 JUN 2006
DOI:10.1002/chem.200600055
The direct electrochemistry of hemoglobin (Hb) was studied in a novel all-carbon nanocomposite film of C60-MWCNT (MWCNT=multiple-walled carbon nanotube) and compared with that in bare MWCNT film. The heterogeneous electron-transfer rate constant ks of Hb/C60-MWCNT was determined to be 0.39 s−1, which is more than one order of magnitude greater than that of Hb/MWCNT (0.03 s−1). The significantly accelerated electron-transfer kinetics are attributed to the mediator role played by C60, which is finely dispersed on the MWCNT surfaces. The excellent stability of Hb/C60-MWCNT was established and its potential application towards the electrocatalytic reduction of O2 was demonstrated.
Co-reporter:Hua Zhang, Louzhen Fan, Yueping Fang, Shihe Yang
Chemical Physics Letters 2005 Volume 413(4–6) pp:346-350
Publication Date(Web):26 September 2005
DOI:10.1016/j.cplett.2005.08.009
Abstract
The electrochemical behavior of a C60/MWCNT (multi-walled carbon nanotube) film cast on GC electrode in acetonitrile solution was investigated. Repeated cyclic voltammetric scans transformed the precursor to a C60–MWCNT composite film which exhibited reversible electron-transfer reactions and superpose the redox feature of the bare MWCNTs with monotonic charge injection over the whole potential range. This is in contrast to both C60 film and peapods of C60 inside carbon nanotubes but resembles the behavior of C60 dissolved in organic solutions. The formation and structure of the C60–MWCNT composite films were studied by UV–Vis, FT-IR, and TEM.
Co-reporter:Louzhen Fan;Ying Liu;Yongfang Li;Shengxiong Xiao;Yuliang Li
Journal of Applied Polymer Science 2002 Volume 86(Issue 11) pp:2737-2741
Publication Date(Web):24 SEP 2002
DOI:10.1002/app.11242
The electrochemical behaviors of a novel class C60 covalently linked PPV derivatives (i.e., PPV-1-C60 and PPV-2-C60) in thin solid films as well as in solutions are reported. The first cathodic peak potentials of PPV-1-C60 and PPV-2-C60 have positive shifts by 30 and 50 mV, respectively, compared to pristine C60 in formal cyclic voltammetry (CV). Simultaneous CV and piezoelectric microgravimetry of the drop-coated thin solid films of PPV-1-C60 and PPV-2-C60 in acetonitrile solutions of TBA+ counteractions are strongly influenced by the structure of the polymer-C60, including the length of the chain macromolecule and the steric hindrance effect. In addition, the atomic force microscopy (AFM) images of PPV-1-C60 and PPV-2-C60 films deposited on Au/quartz electrode both exhibit even distribution. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2737–2741, 2002
Co-reporter:Lirui Nan, Zetan Fan, Wenbo Yue, Qiao Dong, Lisha Zhu, Liu Yang and Louzhen Fan
Journal of Materials Chemistry A 2016 - vol. 4(Issue 22) pp:NaN8904-8904
Publication Date(Web):2016/05/12
DOI:10.1039/C6TA01416J
Noble metal Pd is usually regarded as a promising electrode material for fuel cells due to its high electrocatalytic activity, abundance and greater resistance to CO poisoning. Moreover, the electrocatalytic performance of Pd can be further improved by using novel carbon materials as supports or metal oxides as catalyst promoters. In this work, Pd nanoparticles with a trace of SnO2 are synthesized and anchored on a novel graphene-based porous carbon (G-mC) support by using a modified electroless plating technique. The two-dimensional (2D) porous carbon film on the graphene can separate Pd nanoparticles and limit their growth (<3 nm), while the graphene substrate can enhance the electronic conductivity of the composite. In addition, SnO2 nanoparticles around Pd catalysts may prevent CO poisoning at the catalytic sites, which is beneficial to improving the electrocatalytic performance of Pd catalysts. Therefore, compared to porous carbon (CMK-3) supported Pd catalysts with SnO2 or G-mC supported Pd catalysts without SnO2, G-mC supported Pd catalysts with SnO2 show enhanced electrocatalytic activity and durability for methanol oxidation. In particular, the electrocatalytic activity retention of the composite is maintained at ∼85% after 500 cycles. This novel 2D carbon support is expected to be applied in batteries, supercapacitors or fuel cells.
Co-reporter:Yang Zhang, Wei Liu, Lang Jiang, Louzhen Fan, Chunru Wang, Wenping Hu, Haizheng Zhong, Yongfang Li and Shihe Yang
Journal of Materials Chemistry A 2010 - vol. 20(Issue 5) pp:NaN956-956
Publication Date(Web):2009/12/09
DOI:10.1039/B913897H
Crystal orientation-ordered C60 nanorod bundles have been assembled, where each C60 nanorod maintains its individual shape and identity with unpolymerized bucky balls and all of the nanorods are vertically aligned with a high density. The key to this lies in the assembly of the C60 nanorod bundles from the nanoscopic to microscopic and macroscopic scale. The novel structure of C60 nanorod bundles leads to a high photoresponse, which is promising for applications in optical devices.
Co-reporter:Xiaoyun Tan, Yunchao Li, Xiaohong Li, Shixin Zhou, Louzhen Fan and Shihe Yang
Chemical Communications 2015 - vol. 51(Issue 13) pp:NaN2546-2546
Publication Date(Web):2015/01/08
DOI:10.1039/C4CC09332A
We report water-soluble, 3 nm uniform-sized graphene quantum dots (GQDs) with red emission prepared by electrochemical exfoliation of graphite in K2S2O8 solution. Such GQDs show a great potential as biological labels for cellular imaging.
Co-reporter:Ling Ding, Yifeng E, Louzhen Fan and Shihe Yang
Chemical Communications 2013 - vol. 49(Issue 56) pp:NaN6288-6288
Publication Date(Web):2013/05/23
DOI:10.1039/C3CC42773K
We report a unique strategy for efficiently exfoliating large size and high quality single-layer graphene directly from graphite into DMF dispersions by growing ZnO nanorod arrays between the graphene layers in graphite.
Co-reporter:Changzheng Wang, Yifeng E, Louzhen Fan, Shihe Yang and Yongliang Li
Journal of Materials Chemistry A 2009 - vol. 19(Issue 23) pp:NaN3846-3846
Publication Date(Web):2009/03/31
DOI:10.1039/B821213A
CdS-Ag nanocomposite arrays were successfully prepared by the electrochemical approach based on CdS hierarchical nano-arrays as templates. The optical signatures, including UV-vis absorption, photoluminescence (PL), Raman, and electro-chemiluminescence (ECL), of the CdS-Ag nanocomposite arrays and hierarchical CdS nano-arrays are spectrally distinct, allowing strong coupling between CdS and Ag. A novel hydrogen peroxide ECL sensor based on the CdS-Ag nanocomposite arrays fabricated with our unique assembling strategy has a low detection limit of 1.5 × 10−8 M.
Co-reporter:Weiling Guo, Yifeng E, li Gao, Louzhen Fan and Shihe Yang
Chemical Communications 2010 - vol. 46(Issue 8) pp:NaN1292-1292
Publication Date(Web):2010/01/14
DOI:10.1039/B919370G
We report the first novel cathodic electrochemiluminescence of Ru(bpy)32+ at positive potential of +0.6 V (vs. Ag/AgCl) with a strong light emission clearly visible to the naked eye triggered by reactive oxygen species O2˙− on an in situ electrodeposited Co3O4 nanostructured electrode.
Co-reporter:Hongtao Yu, Yunchao Li, Xiaohong Li, Louzhen Fan and Shihe Yang
Journal of Materials Chemistry A 2014 - vol. 2(Issue 38) pp:NaN15767-15767
Publication Date(Web):2014/09/01
DOI:10.1039/C4TA03476G
The surface charge-tunable Fe3O4 nanoparticles with high dispersibility and high superparamagnetism are fabricated by a facile electrochemical method in acetonitrile. These nanoparticles can reversibly bind to graphene oxides, which could be recycled and continually used for high-efficient removal of dye pollutants from water.
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