Co-reporter:Jingxia Zheng;Yaling Wang;Feng Zhang;Yongzhen Yang;Kunpeng Guo;Hua Wang;Bingshe Xu
Journal of Materials Chemistry C 2017 vol. 5(Issue 32) pp:8105-8111
Publication Date(Web):2017/08/17
DOI:10.1039/C7TC01701D
A one-pot microwave-assisted hydrothermal approach was developed to quickly synthesize organosilane-functionalized carbon dots (Si-CDs) within 5 minutes. With the assistance of N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane (KH-792) as distance barrier chains, aggregation-caused quenching is suppressed successfully, which contributes to the emission of bright blue fluorescence by solid-state Si-CDs (λem ∼ 454 nm). The photoluminescence quantum yield of the as-prepared Si-CDs in the solid state reaches 65.8% with an optimized molar ratio of the reactant citric acid to KH-792 of 1 : 5 and a reaction temperature of 180 °C, which is 2.5-fold that of their solution. Together with their good film-forming ability and thermal stability, Si-CDs were applied to fabricate a white-light-emitting device with color coordinates of (0.32, 0.36) and a correlated color temperature of 6071 K. Our results indicate that the as-prepared Si-CDs are promising materials with efficient solid-state emission to be used in lighting, backlight displays and other optoelectronic devices.
Co-reporter:Yaling Wang, Jingxia Zheng, Junli Wang, Yongzhen Yang, Xuguang Liu
Optical Materials 2017 Volume 73(Volume 73) pp:
Publication Date(Web):1 November 2017
DOI:10.1016/j.optmat.2017.08.032
•Highly luminescent N-CDs were prepared by a facile microwave-assisted hydrothermal method.•N-CDs with the quantum yield of 75.96% were obtained.•The influence of reaction parameters on quantum yield was elucidated by orthogonal experiment.•Warm white LEDs were obtained with color coordinates of (0.42, 0.40) and correlated color temperature of 3416 K.Highly luminescent nitrogen-doped carbon dots (N-CDs) were synthesized rapidly by one-step microwave-assisted hydrothermal method using citric acid as carbon source and ethylenediamine as dopant. The influences of reaction temperature, reaction time and raw material ratio on the fluorescence performance of N-CDs were investigated. Then N-CDs with the highest quantum yield were selected as fluorescent materials for fabricating white light-emitting diodes (LEDs). Highly luminescent N-CDs with the quantum yield of 75.96% and blue-to-red spectral composition of 51.48% were obtained at the conditions of 180 °C, 8 min and the molar ratio of citric acid to ethylenediamine 2:1. As-prepared highly luminescent N-CDs have an average size of 6.06 nm, possess extensive oxygen- and nitrogen-containing functional groups on their surface, and exhibit strong absorption in ultraviolet region. White LEDs based on the highly luminescent N-CDs emit warm white light with color coordinates of (0.42, 0.40) and correlated color temperature of 3416 K.
Co-reporter:Yuanfei Ding;Feng Zhang;Jiacong Xu;Yanqin Miao;Yongzhen Yang;Bingshe Xu
RSC Advances (2011-Present) 2017 vol. 7(Issue 46) pp:28754-28762
Publication Date(Web):2017/05/30
DOI:10.1039/C7RA02421E
Short-chain passivated fluorescent carbon quantum dots (S-CQDs) with graphitic structure were synthesized via a one-step hydrothermal approach using phthalic acid with a benzene ring conjugated structure as the carbon source and ethylenediamine as a nitrogenous additive. The synthesized S-CQDs have an average diameter of 5.53 nm and exhibit excitation-dependent photoluminescence emission. The S-CQD aqueous solution emits bright blue light under ultraviolet excitation with a quantum yield of 29.3%. The optical band gap of the S-CQDs was calculated to be 4.26 eV, the highest occupied molecular orbital and the lowest unoccupied molecular orbital energy levels of −8.35 and −4.09 eV were obtained for the S-CQDs by cyclic voltammetry. In addition, the S-CQDs have a good film-forming ability, as confirmed by atomic force microscopy analysis. By virtue of the structure characteristics, optical properties and the film-forming ability of S-CQDs, quantum dot-based electroluminescent light emitting diodes (QD-LEDs) were fabricated by a solution processing method with S-CQDs as the emitting layer, which emits blue light at 6–9 V driving voltage, showing that the S-CQDs have promising prospects for application in QD-LEDs.
Co-reporter:Yuanfei Ding;Feng Zhang;Jiacong Xu;Yanqin Miao;Yongzhen Yang;Bingshe Xu
RSC Advances (2011-Present) 2017 vol. 7(Issue 46) pp:28754-28762
Publication Date(Web):2017/05/30
DOI:10.1039/C7RA02421E
Short-chain passivated fluorescent carbon quantum dots (S-CQDs) with graphitic structure were synthesized via a one-step hydrothermal approach using phthalic acid with a benzene ring conjugated structure as the carbon source and ethylenediamine as a nitrogenous additive. The synthesized S-CQDs have an average diameter of 5.53 nm and exhibit excitation-dependent photoluminescence emission. The S-CQD aqueous solution emits bright blue light under ultraviolet excitation with a quantum yield of 29.3%. The optical band gap of the S-CQDs was calculated to be 4.26 eV, the highest occupied molecular orbital and the lowest unoccupied molecular orbital energy levels of −8.35 and −4.09 eV were obtained for the S-CQDs by cyclic voltammetry. In addition, the S-CQDs have a good film-forming ability, as confirmed by atomic force microscopy analysis. By virtue of the structure characteristics, optical properties and the film-forming ability of S-CQDs, quantum dot-based electroluminescent light emitting diodes (QD-LEDs) were fabricated by a solution processing method with S-CQDs as the emitting layer, which emits blue light at 6–9 V driving voltage, showing that the S-CQDs have promising prospects for application in QD-LEDs.
Co-reporter:Huan Zhang;Lin Chen;Longfei Li;Yongzhen Yang
Journal of Porous Materials 2017 Volume 24( Issue 2) pp:341-353
Publication Date(Web):2017 April
DOI:10.1007/s10934-016-0267-z
Magnetic porous carbon microspheres (MPCMs) based on Fe3O4-encapsulating carbon composites for removing methylene blue (MB) in aqueous solutions were synthesized by simultaneous activation and magnetization. A series of MPCMs were prepared by combining hydrothermal and annealing treatment with α-Fe2O3 nanoparticles as iron source, glucose as carbon source and ZnCl2 as porogen. The phase structure, specific surface area, porosity, thermostability, magnetic property, as well as morphology of as-prepared MPCMs were verified by X-ray diffraction, Brunauer–Emmeltt–Teller surface area analysis, thermogravimetric analysis, vibrating sample magnetometry, field emission scanning electron microscopy and high resolution transmission electron microscopy. The results indicate that the maximum specific surface area of MPCMs is up to 480.32 m2/g when the mass ratio of ZnCl2/glucose is 0.25, which is designated as MPCMs-0.25. The saturation magnetism of MPCMs-0.25 is 30.16 emu/g. Adsorption properties of MPCMs were detected by using MPCMs-0.25 as adsorbent to remove MB from aqueous solution. The outcomes suggest that the adsorption reaches equilibrium within 35 min and physical adsorption is involved in the whole adsorption processes. The results of adsorption isotherm reveal that the adsorption process might include monolayer and porous adsorption, meanwhile, various adsorption sites exist on the surfaces of MPCMs-0.25. The reusability and stability of MPCMs-0.25 were also confirmed by five adsorption–desorption cycle experiments.
Co-reporter:Feng Zhang, Xiaoting Feng, Yi Zhang, Lingpeng Yan, Yongzhen Yang and Xuguang Liu
Nanoscale 2016 vol. 8(Issue 16) pp:8618-8632
Publication Date(Web):21 Mar 2016
DOI:10.1039/C5NR08838K
Photoluminescent organosilane-functionalized carbon quantum dots (CQDs), 3.0–3.5 nm in diameter, were synthesized via a facile hydrothermal method using citric acid monohydrate as a precursor and N-(3-(trimethoxysilyl) propyl) ethylenediamine as a coordinating and passivation agent. The optical properties of the as-obtained CQDs were investigated in detail. The CQD aqueous solution emits bright blue-white light under ultraviolet (UV) illumination with a quantum yield of 57.3% and high red-green-blue (RGB) spectral composition of 60.1%, and in particular the CQDs exhibit excitation-independent photoluminescence. The CQDs have a narrow size distribution around 3.1 nm and good film-forming ability through simple heat-treatment. By virtue of these excellent optical characteristics and good film-forming ability, a white light-emitting device (LED) was fabricated by combining a UV-LED chip with a single CQD phosphor film, which exhibited cool white light with a CIE coordinate of (0.31, 0.36), a color rendering index of 84 and a correlated color temperature of 6282 K. In addition, the white LED exhibits good optical stability under various working currents and for different working time intervals. Moreover, the interaction between the carbogenic core and surface groups was discussed using the DMol3 program based on density functional theory. This research suggests the great potential of CQDs for solid-state lighting systems and reveals the effect of the surface state on the photoluminescent mechanism of CQDs.
Co-reporter:Xiaorui Jia, Lianping Zhang, Qun Luo, Hui Lu, Xueyuan Li, Zhongzhi Xie, Yongzhen Yang, Yan-Qing Li, Xuguang Liu, and Chang-Qi Ma
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 28) pp:18410-18417
Publication Date(Web):June 28, 2016
DOI:10.1021/acsami.6b03724
We have demonstrated in this article that both power conversion efficiency (PCE) and performance stability of inverted planar heterojunction perovskite solar cells can be improved by using a ZnO:PFN nanocomposite (PFN: poly[(9,9-bis(3′-(N,N-dimethylamion)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctyl)-fluorene]) as the cathode buffer layer (CBL). This nanocomposite could form a compact and defect-less CBL film on the perovskite/PC61BM surface (PC61BM: phenyl-C61-butyric acid methyl ester). In addition, the high conductivity of the nanocomposite layer makes it works well at a layer thickness of 150 nm. Both advantages of the composite layer are helpful in reducing interface charge recombination and improving device performance. The power conversion efficiency (PCE) of the best ZnO:PFN CBL based device was measured to be 12.76%, which is higher than that of device without CBL (9.00%), or device with ZnO (7.93%) or PFN (11.30%) as the cathode buffer layer. In addition, the long-term stability is improved by using ZnO:PFN composite cathode buffer layer when compare to that of the reference cells. Almost no degradation of open circuit voltage (VOC) and fill factor (FF) was found for the device having ZnO:PFN, suggesting that ZnO:PFN is able to stabilize the interface property and consequently improve the solar cell performance stability.
Co-reporter:Lei Qin, Xiaorui Jia, Yongzhen Yang, and Xuguang Liu
Industrial & Engineering Chemistry Research 2016 Volume 55(Issue 6) pp:1710-1719
Publication Date(Web):November 13, 2015
DOI:10.1021/acs.iecr.5b02837
Surface molecular imprinting is an effective way to prepare materials for selective removal of thiophene and its derivatives in transportation fuels and the support material is a crucial factor in determining the adsorption performance of resultant surface molecularly imprinted polymers (SMIP). In this work, a series of SMIP were prepared with dibenzothoiphene (DBT) as a template and various carbon materials as the support for desulfurization of fuel oil. The results demonstrated the porous carbon microspheres (PCMSs) as the support are far superior in preparing SMIP to nonporous carbon microspheres and conventional active carbon. Owing to its porous structure, regular spherical shape, high active surface area and thermal stability, SMIP/PCMSs obtained in this work exhibit excellent performance in the selective removal of DBT, with an outstanding adsorption capacity of 118 mg g–1 and favorable regenerability. In addition, the adsorption kinetic and isotherm outcomes suggest that physical interactions are mainly involved in the whole adsorption processes and the adsorption may be an integrated process of heterogeneous monolayer and multilayer adsorption. The thermodynamic analysis indicates that the adsorption takes place spontaneously and the adsorption process is endothermic, the pore diffusion and mass transfer as well as physical interaction between DBT and SMIP/PCMSs predominate in the whole adsorption process.
Co-reporter:Y. L. Wang, Y. Q. Zhao, Y. Zhang, F. Zhang, X. T. Feng, L. Chen, Y. Z. Yang and X. G. Liu
RSC Advances 2016 vol. 6(Issue 45) pp:38761-38768
Publication Date(Web):13 Apr 2016
DOI:10.1039/C6RA02546C
Nitrogen doped carbon dots (N-CDs) with a quantum yield (QY) of 67.06% and nitrogen sulfur co-doped carbon dots (NS-CDs) with a QY of 9.80% were prepared by a hydrothermal method using citric acid monohydrate as the carbon source and ethylenediamine or thiourea as additives, respectively. The morphology, structure and optical properties of the as-obtained samples were investigated. Notably, the double-bond between the carbon and sulfur antagonized the promotion of QY. Compared with NS-CDs, N-CDs exhibit a high QY, broad and bright light under ultraviolet illumination that would be worth utilizing in a phosphor based on a UV chip. For practical applications, white light-emitting diodes were fabricated by combining the N-CDs/optical encapsulant mixture with a UV chip, which emitted near white light with color coordinates of (0.38, 0.42) and a correlated color temperature of 4290 K.
Co-reporter:Lei Qin, Weiping Shi, Weifeng Liu, Yongzhen Yang, Xuguang Liu and Bingshe Xu
RSC Advances 2016 vol. 6(Issue 15) pp:12504-12513
Publication Date(Web):26 Jan 2016
DOI:10.1039/C5RA23582K
Surface molecular imprinting is an effective measure to get adsorbent materials for definite substances. In this work, ordered mesoporous carbon nanospheres (OMCNS) were prepared as carriers by a hydrothermal method with phenolic resol as the carbon source and triblock copolymer Pluronic PF127 as the soft template. A surface molecularly imprinted polymer (SMIP/OMCNS) was then obtained through a series of functionalization, grafting and elution processes with dibenzothiophene (DBT) as a template, which was designed for the deep desulfurization of fuel products by removing DBT and its derivatives. By adopting OMCNS as a carrier, SMIP/OMCNS shows excellent adsorption capacity towards DBT (218.29 mg g−1), owing to the ordered mesoporous structure and high surface area of OMCNS. The better fitted pseudo-first-order model indicates that the adsorption involves mainly physical interactions, which are promoted by the mesoporous structure of OMCNS. The Langmuir and Freundlich models fitted better than the Dubinin–Radushkevich and Scatchard isothermal models did, which suggests the occurrence of both monolayer and multilayer interactions. The thermodynamics, selectivity and regenerability of SMIP/OMCNS were also investigated. The adsorption of DBT on SMIP/OMCNS proves to be an endothermic process. And the relative selectivity coefficients against benzothiophene, biphenyl and fluorine interferents reached 2.19, 2.29 and 2.37, respectively. As a result, SMIP/OMCNS can be a potential adsorbent material for deep desulfurization of fuel products and recovering DBT and its derivatives as valuable reagents for other value-added applications.
Co-reporter:Zhi Yang, Guoqiang Lan, Bin Ouyang, Li-Chun Xu, Ruiping Liu, Xuguang Liu, Jun Song
Materials Chemistry and Physics 2016 Volume 183() pp:6-10
Publication Date(Web):1 November 2016
DOI:10.1016/j.matchemphys.2016.08.050
•There exist Dirac cones in three-dimensional (3D) graphene.•The thermoelectric performance of 3D graphene is excellent.•The defective 3D graphene has better thermoelectric performance.The electronic and thermoelectric properties of a new carbon bulk material, three-dimensional (3D) graphene, are investigated in this study. Our results show that 3D graphene has unique electronic structure, i.e., near the Fermi level there exist Dirac cones. More importantly, the thermoelectric performance of 3D graphene is excellent, at room temperature the thermoelectric figure of merit (ZT) is 0.21, an order of magnitude higher than that of graphene. By introducing line defects, the ZT of 3D graphene could be enhanced to 1.52, indicating 3D graphene is a powerful candidate for constructing novel thermoelectric materials.
Co-reporter:Xiaoting Feng;Feng Zhang;Yaling Wang;Yi Zhang
Journal of Electronic Materials 2016 Volume 45( Issue 6) pp:2784-2788
Publication Date(Web):2016 June
DOI:10.1007/s11664-016-4407-7
Synthesis of fluorescent carbon quantum dots (CQDs) as single light converter and their application in white light-emitting diodes (LEDs) are reported. CQDs were prepared by a one-step hydrothermal method using glucose and polyethylene glycol 200 as precursors. The structural and optical properties of the CQDs were investigated. The CQDs with uniform size of 4 nm possessed typical excitation-dependent emission wavelength and quantum yield of 3.5%. Under ultraviolet illumination, the CQDs in deionized water emitted bright blue fluorescence and produced broad visible-light emission with high red, green, and blue spectral component ratio of 63.5% (red-to-blue intensity to total intensity), suggesting great potential as single light converter for white LEDs. To demonstrate their potential, a white LED using CQDs as a single light converter was built. The device exhibited cool white light with corresponding color temperature of 5584 K and color coordinates of (0.32, 0.37), belonging to the white gamut. This research suggests that CQDs could be a promising candidate single light converter for white LEDs.
Co-reporter:Lan-Song Li;Yu-Ping Meng;Qiu-Fen Cao;Yong-Zhen Yang;Fan Wang
Biochemistry (Moscow) 2016 Volume 81( Issue 6) pp:565-573
Publication Date(Web):2016 June
DOI:10.1134/S000629791606002X
Metallothioneins (MTs) are a family of low molecular weight, cysteine-rich, metal-binding proteins that are able to make cells to uptake heavy metals from the environment. Molecular and functional characterization of this gene family improves understanding of the mechanisms underlying heavy metal tolerance in higher organisms. In this study, a cDNA clone, encoding 74-a.a. metallothionein type 1 protein (ZjMT), was isolated from the cDNA library of Ziziphus jujuba. At the N- and C-terminals of the deduced amino acid sequence of ZjMT, six cysteine residues were arranged in a CXCXXXCXCXXXCXC and CXCXXXCXCXXCXC structure, respectively, indicating that ZjMT is a type 1 MT. Quantitative PCR analysis of plants subjected to cadmium stress showed enhanced expression of ZjMT gene in Z. jujuba within 24 h upon Cd exposure. Escherichia coli cells expressing ZjMT exhibited enhanced metal tolerance and higher accumulation of metal ions compared with control cells. The results indicate that ZjMT contributes to the detoxification of metal ions and provides marked tolerance against metal stresses. Therefore, ZjMT may be a potential candidate for tolerance enhancement in vulnerable plants to heavy metal stress and E. coli cells containing the ZjMT gene may be applied to adsorb heavy metals in polluted wastewater.
Co-reporter:Longfei Li, Lin Chen, Huan Zhang, Yongzhen Yang, Xuguang Liu, Yongkang Chen
Materials Science and Engineering: C 2016 Volume 61() pp:158-168
Publication Date(Web):1 April 2016
DOI:10.1016/j.msec.2015.12.027
•Temperature and magnetism responsive molecularly imprinted polymers were prepared.•Drug-loading and molecule recognition ability were confirmed.•The 5-fluorouracil adsorption/release activities could be modulated by temperature.•Adsorption mechanism was explored by using computational analysis.Temperature and magnetism bi-responsive molecularly imprinted polymers (TMMIPs) based on Fe3O4-encapsulating carbon nanospheres were prepared by free radical polymerization, and applied to selective adsorption and controlled release of 5-fluorouracil (5-FU) from an aqueous solution. Characterization results show that the as-synthesized TMMIPs have an average diameter of about 150 nm with a typical core–shell structure, and the thickness of the coating layer is approximately 50 nm. TMMIPs also displayed obvious magnetic properties and thermo-sensitivity. The adsorption results show that the prepared TMMIPs exhibit good adsorption capacity (up to 96.53 mg/g at 25 °C) and recognition towards 5-FU. The studies on 5-FU loading and release in vitro suggest that the release rate increases with increasing temperature. Meanwhile, adsorption mechanisms were explored by using a computational analysis to simulate the imprinted site towards 5-FU. The interaction energy between the imprinted site and 5-FU is − 112.24 kJ/mol, originating from a hydrogen bond, Van der Waals forces and a hydrophobic interaction between functional groups located on 5-FU and a NIPAM monomer. The electrostatic potential charges and population analysis results suggest that the imprinted site of 5-FU can be introduced on the surface of TMMIPs, confirming their selective adsorption behavior for 5-FU.Temperature and magnetism bi-responsive molecularly imprinted polymers (TMMIPs) were prepared, which showed excellent magnetic properties, thermo-sensitivity, drug-loading and recognition ability towards 5-fluorouracil (5-FU). Adsorption mechanisms were explored by using a computational analysis to simulate the imprinted site towards 5-FU. The electrostatic potential charges and population analysis results suggested that TMMIPs can be the selective sorbent of 5-FU, because of the obvious affinity between the imprinted site and 5-FU.
Co-reporter:Yi Zhang, Peipei Cui, Feng Zhang, Xiaoting Feng, Yaling Wang, Yongzhen Yang, Xuguang Liu
Talanta 2016 Volume 152() pp:288-300
Publication Date(Web):15 May 2016
DOI:10.1016/j.talanta.2016.02.018
•Nitrogen-doped carbon dots (NCDs) from ammonia solution and citric acid were synthesized.•NCDs were applied in the detection of Hg2+ and L-Cys in spiked water samples.•Hg2+ quenches the fluorescence of NCDs by the formation of a stable NCDs–Hg2+ complex.•L-Cys shelters the quenching through formation of a more stable Hg2+–L-Cys complex.•NCDs exhibit high sensitivity, selectivity and low detection limit to Hg2+ and L-Cys.Fluorescent nitrogen-doped carbon dots (NCDs) were synthesized by a facile, and low-cost one-step hydrothermal strategy using citric acid as carbon source and ammonia solution as nitrogen source for the first time. The obtained NCDs show stable blue fluorescence with a high quantum yield of 35.4%, along with the fluorescence lifetime of ca. 6.75 ns. Most importantly, Hg2+ can completely quench the fluorescence of NCDs as a result of the formation of a non-fluorescent stable NCDs–Hg2+ complex. Static fluorescence quenching towards Hg2+ is proved by the Stern–Volmer equation, ultraviolet–visible absorption spectra, temperature dependent quenching and fluorescence lifetime measurements. Subsequently, the fluorescence of the NCDs–Hg2+ system is completely recovered with the addition L-cysteine (L-Cys) owing to the dissociation of NCDs–Hg2+ complex to form a more stable Hg2+-L-Cys complex by Hg2+–S bonding. Therefore, such NCDs can be used as an effective fluorescent “turn-off” probe for rapid, rather highly selective and sensitive detection of Hg2+, with a limit of detection (LOD) as low as 1.48 nM and a linear detection range of 0–10 μM. Interestingly, NCDs–Hg2+ system can be conveniently employed as a fluorescent “turn-on” sensor for highly selective and sensitive detection of L-Cys with a low LOD of 0.79 nM and a wide linear detection range of 0–50 μM. Further, the sensitivity of NCDs to Hg2+ is preserved in tap water with a LOD of 1.65 nM and a linear detection range of 0–10 μM.Fluorescence turn “off-on” probes based on nitrogen-doped carbon dots can be used for Hg2+ and L-cysteine detection in aqueous solution.
Co-reporter:Feifei Duan, Chaoqiu Chen, Xiaofeng Zhao, Yongzhen Yang, Xuguang Liu and Yong Qin
Environmental Science: Nano 2016 vol. 3(Issue 1) pp:213-222
Publication Date(Web):04 Jan 2016
DOI:10.1039/C5EN00198F
Water-compatible molecularly imprinted polymers (MIPs) with dual monomer–template interactions were synthesized via the synergy of bi-functional monomers of water-soluble 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and styrene (St) for the selective adsorption of bisphenol A (BPA) from aqueous media using porous graphene oxide as a support. Both hydrogen bonds and π–π interactions are responsible for the adsorption of BPA on the synthesized MIPs. The formation and structure of the MIPs are verified by Fourier transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy and dispersion analysis in water. The adsorption results show that the adsorption capacity of MIPs is greatly enhanced by virtue of the synergy of AMPS and St. The MIPs prepared with a molar ratio (AMPS:St) of 2.5:2.5 exhibit the highest adsorption capacity (up to 85.7 mg g−1 at 293 K) toward BPA in aqueous media. The kinetics and isotherm data can be well fitted with the pseudo-second-order kinetic model and the Freundlich isotherm, respectively. Competitive adsorption experiments demonstrate that the synthesized MIPs display excellent selectivity toward BPA against analogue molecules. The MIPs show good recoverability and exhibit excellent adsorption affinity toward BPA even in complex river water. This work provides a versatile approach for the fabrication of high performance MIPs for application in aqueous environments.
Co-reporter:W. P. Shi, W. F. Liu, L. Chen, L. Qin, Y. Z. Yang and X. G. Liu
RSC Advances 2015 vol. 5(Issue 129) pp:106787-106794
Publication Date(Web):10 Dec 2015
DOI:10.1039/C5RA19326E
Carbon-encapsulated Fe3O4 nanospheres were synthesized by a one-step solvothermal method. The effect of annealing temperature on the structure of carbon-encapsulated Fe3O4 nanospheres was investigated. The morphologies and microstructures of all the products were characterized by field emission scanning electron microscopy, high resolution transmission electron microscopy, X-ray diffraction, N2 adsorption–desorption isotherms, thermogravimetry and vibrating sample magnetometry. The results show that the as-obtained carbon-encapsulated Fe3O4 nanospheres possess a core–shell structure with a size of about 120 nm. The thickness of the carbon layer, specific surface area and pore volume are 20 nm, 33 m2 g−1 and 0.06 cm3 g−1, respectively. With the increase of annealing temperature from 300 to 500 °C for 1 h, the carbon layer of the carbon-encapsulated Fe3O4 nanospheres becomes thinner, and the specific surface area and pore volume become larger. After annealing at 500 °C, the carbon layer thickness, specific surface area and pore volume of the carbon-encapsulated Fe3O4 nanospheres are 13 nm, 191 m2 g−1 and 0.14 cm3 g−1, respectively. After annealing at 600 °C, the carbon-encapsulated Fe3O4 nanospheres change to a yolk–shell structure. When annealed at 700 °C, the carbon layer is destroyed and some Fe nanoparticles are exposed. A plausible formation mechanism for yolk–shell Fe3O4@C nanospheres is proposed.
Co-reporter:Lingpeng Yan, Yamin Hao, Xiaoting Feng, Yongzhen Yang, Xuguang Liu, Yongkang Chen and Bingshe Xu
RSC Advances 2015 vol. 5(Issue 97) pp:79860-79867
Publication Date(Web):07 Sep 2015
DOI:10.1039/C5RA16854F
Sandwich-like Ag–C–Ag nanoparticles (Ag–C–Ag NPs) were synthesized under mild hydrothermal conditions in a one-step method. With this approach, Ag was not only encapsulated in the centre of an individual carbon nanosphere, but was also uniformly dispersed within the carbon matrix up to the sphere's shell. Then, poly(3-hexylthiophene):Ag–C–Ag NPs (P3HT:Ag–C–Ag NPs) composite films were prepared by a spin coating method with a chlorobenzene solution of Ag–C–Ag NPs and P3HT. Both morphology and microstructure of Ag–C–Ag NPs were investigated by field emission scanning electron microscopy and high resolution transmission electron microscopy. The possible formation mechanism was proposed. The results have indicated that the Ag–C–Ag NPs present many functional groups and their energy levels match with those of P3HT. It has been observed that an introduction of Ag–C–Ag NPs to P3HT can induce broad and high-absorbing spectra as well as great photoluminescence quenching of P3HT. It is evident that sandwich-like Ag–C–Ag NPs have a great potential to be a new acceptor material in photovoltaic devices.
Co-reporter:Y. Zhang, Y. H. He, P. P. Cui, X. T. Feng, L. Chen, Y. Z. Yang and X. G. Liu
RSC Advances 2015 vol. 5(Issue 50) pp:40393-40401
Publication Date(Web):05 May 2015
DOI:10.1039/C5RA04653J
Highly fluorescent water-soluble and nitrogen-doped carbon dots (NCDs) were synthesized by a simple one-pot hydrothermal method using citric acid as carbon source and urea as nitrogen source. Quantum yield of NCDs reaches 42.2%. As-obtained NCDs show a strong emission at 440 nm with an optimum excitation at 355 nm, and exhibit high photostability and excitation-independent photoluminescence (PL) behavior under excitation at 240–380 nm. However, such NCDs show excitation-dependent PL behavior under excitation of 380–480 nm. Because of the Hg2+-induced fluorescence quenching of carbon dots (CDs), such NCDs can be used as an effective fluorescent nanoprobe for highly selective and sensitive detection of Hg2+ in aqueous solution, with a limit of detection (LOD) as low as 2.91 nM in a linear range of 0–50 nM. The NCDs offer a rapid detection of Hg2+ with one-step rapid operation within 5 min. Further, as-prepared NCDs also exhibit high sensitivity towards Hg2+ in tap water and mineral water samples. The linear ranges of detection are both 0–50 nM. The LODs in tap water and mineral water samples are as low as 2.88 nM and 2.87 nM, respectively.
Co-reporter:Xiaoliang Yan, Sha Li, Yunxiang Pan, Bin Xing, Ruifeng Li, Ben W.-L. Jang and Xuguang Liu
RSC Advances 2015 vol. 5(Issue 49) pp:39384-39391
Publication Date(Web):10 Apr 2015
DOI:10.1039/C5RA02904J
Silver nanoparticles have been regarded as promising candidates in the market as antibacterial agents. However, large production volumes and toxic nature of silver lead to potentially adverse effects on human health and environment, and the rapid consumption of Ag+ ion results in short-term efficacy. In this study, carbon-encapsulated Ag (Ag@C) was designed and used as an antibacterial agent in view of the superior antibacterial property of silver nanoparticles, and a tunable Ag+ ion release rate, which was achieved by varying the thickness of the carbon shell. Structural changes were systematically investigated by a series of experimental and theoretical studies. The results showed the evolution of Ag@C from Ag nanoparticles to triangular Ag nanoplates and finally to carbon-encapsulated hexagonal Ag nanoplates. The antibacterial and antifouling performances of Ag@C towards Escherichia coli/Staphylococcus aureus and Platymonas subcordiformis/Tropidoneis lepidoptera were investigated and the antibacterial mechanism was also discussed. The released Ag+ ion concentrations were controllable and sustainable at 39.4 and 0.667 ppb for Ag@C with carbon shell thicknesses of 31.5 and 247 nm, which attenuated the toxicity of the Ag nanoparticles. Ag@C showed stable antibacterial and antifouling properties and proved to be potentially suitable for biological and environmental applications.
Co-reporter:Lin Chen;Huan Zhang;Longfei Li;Yongzhen Yang;Bingshe Xu
Journal of Applied Polymer Science 2015 Volume 132( Issue 40) pp:
Publication Date(Web):
DOI:10.1002/app.42617
ABSTRACT
Thermoresponsive hollow magnetic microspheres consisting of a hollow magnetic core, a carbon shell, and a smart polymer layer are presented in this article. A carbon nanomaterial was used as a steric stabilizer for Fe3O4 nanoparticles and a supporter for polymer. The thermoresponsive monomer, N-isopropyl acrylamide, was grafted on the carbon-encapsulate hollows by surface radical polymerization. The experimental results indicate that the composites had a phase-transition temperature around 43°C and a saturation magnetization of 56.9 emu/g; this showed apparent thermosensitivity and magnetism. The performances in hyperthermia evaluated by an inductive magnetic field showed that the hybrid microspheres had a specific absorption rate of 240 W/g. The model drug, 5-fluorouracil, was loaded in and released from the microspheres with different release rates at 35 and 50°C. This demonstrated that the as-synthesized microspheres had a thermotriggered release ability and would be a good drug carrier in the biomedical field. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42617.
Co-reporter:Zhi Yang, Yu-Long Ji, Guoqiang Lan, Li-Chun Xu, Xuguang Liu, Bingshe Xu
Solid State Communications 2015 Volume 217() pp:38-42
Publication Date(Web):September 2015
DOI:10.1016/j.ssc.2015.05.013
Highlights•Full-boron fullerene B40 was applied to design molecular device.•Large rectification ratio was observed in the molecular device.•The molecular device has excellent optical properties and can be used as photodetector.All-boron fullerene B40 is a highly stable molecule, which has been successfully synthesized in recent experiment. In this paper, with Au as two electrodes, the single-molecule device Au–B40–Au was investigated by using density functional theory and non-equilibrium Green׳s function method. The results show that the device can exhibit large rectification ratio and significant negative differential resistance. More importantly, the photocurrent of the device has different responses in the infrared, visible and ultraviolet regions. The excellent optoelectronic properties ensure that the device can be used as photodetector.
Co-reporter:Lei Qin;Weifeng Liu;Yongzhen Yang
Monatshefte für Chemie - Chemical Monthly 2015 Volume 146( Issue 3) pp:449-458
Publication Date(Web):2015 March
DOI:10.1007/s00706-014-1311-9
Three candidate monomers (methacrylic acid, 2-vinyl pyridine, and 2-acrylamide-2-methyl sulfuric acid) were screened through computational simulation method to prepare effective surface molecularly imprinted polymers (SMIPs) based on carbon microspheres (CMSs) for dibenzothiophene removal from fuels. The optimized structures of complexes were described using density functional theory calculation at B3LYP/6-311++G(d,p) level and frequency calculations for each molecule and complex were conducted to provide insights into electrostatic interaction between monomers and template DBT. Besides, the reliability of computational simulation method for screening was tested by comparing the theoretical data with experimental results from gas chromatography. The computational data suggest that methacrylic acid (MAA) was the preferred monomer with the largest absolute binding energy (14.79 kJ mol−1), which is in accordance with the experimental results. The
saturated adsorption of PMAA-SMIPs/CMSs was the best (41.73 mg g−1). Besides, PMAA-SMIPs/CMSs show highest special selectivity for dibenzothiophene against benzothiophene, and the relative selectivity coefficient k′ was 2.02. The computational simulation method can be effectively used in monomer screening. This work may help understand the mechanisms of polymerization and recognition process between SMIPs and template and design SMIPs with improved adsorption performance.
Co-reporter:Feifei Duan, Chaoqiu Chen, Lin Chen, Yongjiao Sun, Yunwei Wang, Yongzhen Yang, Xuguang Liu, and Yong Qin
Industrial & Engineering Chemistry Research 2014 Volume 53(Issue 37) pp:14291-14300
Publication Date(Web):August 21, 2014
DOI:10.1021/ie5028099
Water-compatible molecularly imprinted polymers (MIPs) for adsorbing bisphenol A (BPA) in aqueous solutions are synthesized using water-soluble monomer as surface hydrophilicity-increasing agent via surface addition–fragmentation chain transfer polymerization. The formation and structure of these hybrid materials are verified by Fourier transform infrared spectroscopy, contact angle studies, thermogravimetric analysis, and scanning electron microscopy. The characterization and adsorption results indicate that the molecularly imprinted polymers prepared with 2-acrylamido-2-methylpropanesulfonic acid (AMPS/MIPs) are water-compatible (the contact angle is 14°). The excellent dispersion of AMPS/MIPs in water provides more opportunity for BPA molecules to access the imprinted cavities and improves their recognition characteristics. The kinetics and isotherm data of AMPS/MIPs can be well described by the pseudo-second-order kinetic model and the Langmuir isotherm, respectively. The thermodynamic studies indicate that the adsorption process is a spontaneous exothermic process.
Co-reporter:Sha Li, Xiaoliang Yan, Zhi Yang, Yongzhen Yang, Xuguang Liu, Jing Zou
Applied Surface Science 2014 Volume 292() pp:480-487
Publication Date(Web):15 February 2014
DOI:10.1016/j.apsusc.2013.11.166
Highlights
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The effects of glucose concentration and hydrothermal reaction time on the size and morphology of CMSs were studied.
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RF plasma reduced Ag+ ions to metallic nanoparticles.
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The formation mechanism of the structure of Ag decorated CMSs was discussed.
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RF plasma produced Ag/CMSs hybrid materials showed superior antibacterial property.
Co-reporter:Xingmei Guo, Zefeng Du, Maoning Song, Li Qiu, Yinghua Shen, Yongzhen Yang, Xuguang Liu
Applied Surface Science 2014 Volume 321() pp:116-125
Publication Date(Web):1 December 2014
DOI:10.1016/j.apsusc.2014.09.130
Highlights
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Thermosensitive polymer PNIPAM was grafted on the surface of carbon spheres.
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The PNIPAM grafted-carbon spheres composites are temperature responsive.
- •
The grafting conditions have major impact on volume phase transition temperature.
- •
The LCST of the composites was adjustable by changing the grafting conditions.
Co-reporter:Zhi Yang, Donghong Wang, Li-Chun Xu, Xuguang Liu, Xiuyan Li, Bingshe Xu
International Journal of Hydrogen Energy 2014 Volume 39(Issue 34) pp:19621-19629
Publication Date(Web):20 November 2014
DOI:10.1016/j.ijhydene.2014.09.125
•The hydrogen storage capacities of FeC5H5, Fe2C5H5 and (FeC5H5)∞ were investigated.•The hydrogen storage capacities of FeC5H5 and Fe2C5H5 are 7.63 wt% and 10.15 wt%.•(FeC5H5)∞ can adsorb H2 molecules, and the hydrogen storage capacity is 1.62 wt%.•The magnetic and electrical properties of (FeC5H5)∞ are sensitive to additional H2.Based on density functional theory, the capacities of FeC5H5, Fe2C5H5 and one-dimensional (FeC5H5)∞ nanowire as hydrogen storage media were investigated. The results show that FeC5H5 and Fe2C5H5 can adsorb five and ten H2 molecules, respectively, and form stable FeC5H5(H2)5 and Fe2C5H5(H2)10 systems. The hydrogen storage capacities of the two systems are 7.63 wt% and 10.15 wt%, while the average adsorption energies are 0.49 and 0.73 eV/H2, indicating that FeC5H5 and Fe2C5H5 are excellent hydrogen storage media. In addition, (FeC5H5)∞ nanowire can also adsorb H2 molecules (1.62 wt%). Most importantly, the magnetic and electrical properties of the nanowire are sensitive to the additional H2, thus (FeC5H5)∞ can be used for selecting and detecting H2 molecules.
Co-reporter:Lin Chen, Longfei Li, Huan Zhang, Weifeng Liu, Yongzhen Yang, Xuguang Liu and Bingshe Xu
RSC Advances 2014 vol. 4(Issue 87) pp:46806-46812
Publication Date(Web):18 Sep 2014
DOI:10.1039/C4RA09393C
In order to explore a stable and biocompatible material for encapsulating magnetic nanoparticles and supporting thermosensitive polymers, the present study describes a facile route for preparing monodisperse hybrid microspheres with superparamagnetic cores, in which Fe3O4 nanocrystals are encapsulated in carbon microsphere matrices (Fe3O4/carbon). Magnetic thermosensitive core/shell structure microspheres were prepared using Fe3O4/carbon microspheres as cores, N-isopropylacrylamide as a thermosensitive monomer, potassium persulfate as initiator and N,N-methylene bisacrylamide as crosslinker. A series of investigations using field emission scanning electron microscopy, transmission electron microscopy, Fourier transformation infrared spectroscopy, thermogravimetry and dynamic light scattering was carried out to characterize the hybrid microspheres. The as-synthesized microspheres have a hydrodynamic diameter of 280 nm with a lower critical solution temperature at around 45 °C. They are superparamagnetic with a saturation magnetization of 13.75 emu g−1 at 20 kOe. They generate heat when an inductive magnetic field is applied to them and have a specific absorption rate of 77.0 W g−1 at 230 kHz and 290 Oe, showing good potential for hyperthermia. The controlled release experiments demonstrate that the microspheres have excellent drug-loading and temperature-triggered drug-release ability for 5-fluorouracil.
Co-reporter:Weifeng Liu, Lei Qin, Yongzhen Yang, Xuguang Liu, Bingshe Xu
Materials Chemistry and Physics 2014 Volume 148(Issue 3) pp:605-613
Publication Date(Web):15 December 2014
DOI:10.1016/j.matchemphys.2014.08.024
•DBT imprinting was performed towards the grafted polymethacrylic acid.•DBT-MIPs based on iniferter-modified CMSs were prepared.•MIPs-CMSs exhibit high binding affinity and recognition selectivity for DBT.•MIPs-CMSs has prospect to be used in deep desulfurization of fuel oils.Molecularly imprinted polymers (MIPs) on the surface of iniferter-modified carbon microspheres (CMSs) were synthesized by using dibenzothiophene (DBT) as the template molecule, methacrylic acid as the functional monomer and ethylene glycol dimethacrylate as the crosslinker. The influencing factors of monomer-grafting process were investigated. The characterizations of structure and morphology suggest that a thin layer of MIPs was grafted on the surface of CMSs under the optimized conditions. The adsorption results show MIPs-CMSs possessed higher binding capacity and selectivity than non-imprinted polymers on CMSs (NIPs-CMSs), and exhibited a good competitive adsorption capacity for DBT. The maximum adsorption capacity of MIPs-CMSs towards DBT reached 88.83 mg g−1. In addition, the adsorption of DBT on MIPs-CMSs follows Langergren pseudo second order model and Langmuir–Freundlich isotherm. Negative values of the Gibbs free energy, positive values of standard enthalpy and entropy reveal that the adsorption was a spontaneous, endothermic and entropically driven process during 288–318 K. From the regeneration experiments and adsorption results in the real oil, it is concluded that the MIPs-CMSs could be used in deep desulfurization of fuel oils.Surface molecularly imprinted carbon microspheres were synthesized by grafting-polymerization method, which offer high binding capacity and selectivity for removing of dibenzothiophene from model fuel oils.
Co-reporter:Yong-zhen Yang, Xu-guang Liu, Bing-she Xu
New Carbon Materials 2014 Volume 29(Issue 1) pp:1-14
Publication Date(Web):February 2014
DOI:10.1016/S1872-5805(14)60121-9
As a novel adsorptive desulfurization method for the preparation of adsorbents, molecular imprinting technology is used to create specific molecular recognition sites in polymers to identify sulfur-bearing template molecules. It is a green process with potential applications because of its characteristics of mild conditions, simple operation, low investment, low pollution, high selectivity, no effect on octane value, and the possible reuse of the as-obtained benzothiophene-like compounds as fine chemicals. Recently, inorganic materials including silica gel, TiO2, K2Ti4O9, and carbon microspheres have been used as supports to prepare surface molecularly imprinted polymers for adsorbing dibenzothiophene and benzothiophene. Recent advances in molecular imprinting technology for deep desulfurization are summarized with carbon microsphere surface molecular imprinting technology highlighted. The review provides experimental references and theoretical guidance for designing and preparing green desulfurization materials.
Co-reporter:Weifeng Liu, Xuguang Liu, Yongzhen Yang, Yan Zhang, Bingshe Xu
Fuel 2014 Volume 117(Part A) pp:184-190
Publication Date(Web):30 January 2014
DOI:10.1016/j.fuel.2013.09.031
•Novel double-template molecularly imprinted materials D-MIP/CMSs were prepared.•The D-MIP/CMSs have good selectivity for benzothiophene and dibenzothiophene.•The D-MIP/CMSs can be used for quickly removing benzothiophenes in fuel oil.•Computer simulation was used for confirming the experimental results.A novel double-template molecularly imprinted polymer (D-MIP) on the surface of carbon microspheres (CMSs), using benzothiophene (BT) and dibenzothiophene (DBT) as the template molecules, was prepared for the removal of benzothiophene sulfides from fuel gasoline. Field emission scanning electron microscopy and Fourier Transformation Infrared Spectrometry were used to characterize the morphology and structure of the D-MIP/CMSs. The adsorption behaviors of the D-MIP/CMSs including adsorption kinetics, isotherms, selectivity and regeneration were detected in detail by gas chromatography. The D-MIP/CMSs exhibited excellent selectivity toward BT and DBT with higher binding capacity in simulated gasoline compared to non-imprinted polymer (D-NIP/CMSs). The adsorption equilibrium of D-MIP/CMSs was achieved within 90 min and the adsorption capacity reached 57.16 (BT) and 67.19 mg g−1 (DBT), respectively. The pseudo-second order model and Langmuir–Freundlich isotherm described the adsorption of benzothiophene sulfides on the D-MIP/CMSs well. The D-MIP/CMSs could be used 10 times without significant loss in adsorption capacity. In addition, the D-MIP/CMSs exhibited good desulfurization effect in real oil. The D-MIP/CMSs provides a new material for deep desulfurization of fuel oils.Graphical abstractNovel double-template surface molecularly imprinted carbon microspheres were synthesized by using benzothiophene and dibenzothiophene as template molecules, which offer high binding capacity and selectivity for removal of sulfur-containing compounds from model fuel oil.
Co-reporter:Zhi Yang ; Donghong Wang ; Xuguang Liu ; Li-Chun Xu ; Shijie Xiong ;Bingshe Xu
The Journal of Physical Chemistry C 2014 Volume 118(Issue 51) pp:29695-29703
Publication Date(Web):December 11, 2014
DOI:10.1021/jp511443j
The chemical bonds and magnetic and quantum transport properties of small-sized transition-metal-pentalene sandwich clusters TM2nPnn+1 (TM = V, Cr, Mn, Co, and Ni; n = 1, 2) were investigated by using density functional theory and nonequilibrium Green’s function method. Theoretical results show that TM2nPnn+1 sandwiches have high stabilities. The TM–TM bond order gradually decreases with the increase of 3d electron number of TM atoms and TM2nPnn+1 could exhibit different spin states. With Au as two electrodes, significant spin-filter capability was observed in TM2nPnn+1, and such a filter can be switched on/off by changing the spin state. In addition, giant magnetoresistance was also found in the systems. These interesting quantum transport properties indicate that TM2nPnn+1 sandwiches are promising materials for designing molecular junction with different functions.
Co-reporter:Weifeng Liu, Huijun Zhao, Yongzhen Yang, Xuguang Liu, Bingshe Xu
Applied Surface Science 2013 Volume 277() pp:146-154
Publication Date(Web):15 July 2013
DOI:10.1016/j.apsusc.2013.04.016
Highlights
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MIP-DBT based on CMSs activated by 4-(chloro)phenyltrimethoxysilane was prepared.
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The optimized conditions of silanization were obtained.
- •
The resulting MIP-DBT/CMSs exhibited high binding capacity and selectivity for DBT.
- •
The MIP-DBT/CMSs has prospect to be used in deep desulfurization of fuel oils.
Co-reporter:Zhi Yang, Baolong Zhang, Xuguang Liu, Yongzhen Yang, Xiuyan Li, Shijie Xiong, Bingshe Xu
Organic Electronics 2013 Volume 14(Issue 11) pp:2916-2924
Publication Date(Web):November 2013
DOI:10.1016/j.orgel.2013.08.016
•Different-sized vanadium–naphthalene sandwich clusters are all very stable and could exhibit rich magnetic properties.•The spin-filter capability and negative differential resistance can be observed in these systems.•The giant magnetoresistance effect was also found in the sandwiches and the transport properties can be adjusted according to cluster size.Using density functional theory and non-equilibrium Green’s function technique, we performed theoretical investigations on the magnetic and transport properties of V2n(C10H8)n+1 (n = 1–4) sandwich clusters. For the ground states, our results show that all the clusters are stable and possess ferromagnetic orders. The smaller clusters have higher stabilities, and our predictions are in agreement with the experimental observation. The double exchange mechanism plays an important role in determining the magnetic properties of the systems. Furthermore, with Ni as electrodes, the clusters exhibit interesting transport properties such as significant spin-filter capability, negative differential resistance feature and giant magnetoresistance effect. These findings suggest that V2n(C10H8)n+1 sandwiches are excellent candidates for application in spintronics and organic electronics.The giant magnetoresistance effects of different-sized vanadium–naphthalene sandwich clusters.
Co-reporter:Xingmei Guo, Haixing Liu, Yinghua Shen, Mei Niu, Yongzhen Yang, Xuguang Liu
Applied Surface Science 2013 Volume 283() pp:215-221
Publication Date(Web):15 October 2013
DOI:10.1016/j.apsusc.2013.06.084
Highlights
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Theoretical calculation predicted the bandgap characteristics of silica-coated CSs.
- •
Experiment proved that silica-coated CSs composites had been prepared.
- •
pH value played an important role in coating reaction.
- •
Amount of precursor and reaction time had a mainly effect on coating ratios.
- •
The CSs coated with silica had good dispersibility in water and ethanol.
Co-reporter:Li Qiu;Yongzhen Yang;Lihua Xu
Polymer Composites 2013 Volume 34( Issue 5) pp:656-664
Publication Date(Web):
DOI:10.1002/pc.22465
Abstract
The melt-mixing polyamide 66 (PA66) composite samples that incorporated pure, acid- and amine-functionalized multiwalled carbon nanotubes (MWCNTs) were prepared in order to enhance mechanical and frictional properties of PA66 composites. The homogeneous dispersion of amine-functionalized MWCNTs (D-MWCNTs) in PA66 matrix was observed from the significantly uniform morphology of tensile fractured surface of the composites. Differential scanning calorimetry measurement indicates that D-MWCNTs acted as effective nucleation agent for PA66 matrix and the crystallinity of PA66 was increased. The fracture stress and tensile modulus of the composites were significantly improved with the incorporation of D-MWCNTs, owing to the good dispersion of D-MWCNTs. Compared with PA66, the PA66 composites with 1.0 wt% D-MWCNTs were improved considerably in both wear and friction properties owing to the change of the tribological mechanisms. The good dispersion of D-MWCNTs in PA66 and good interface compatibility between D-MWCNTs and PA66 favored the formation of a thin layer on the contact surfaces during wear and friction test, which played an important role in reducing wear and friction of the composite and in suppressing the transverse cracks. These results prove the importance of D-MWCNTs in a positive change of the mechanical and frictional properties of PA66 composites and suggest the applicability prospect of PA66/D-MWCNTs composites in engineering components.POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers
Co-reporter:Yongzhen Yang, Yan Zhang, Sha Li, Xuguang Liu, Bingshe Xu
Applied Surface Science 2012 Volume 258(Issue 17) pp:6441-6450
Publication Date(Web):15 June 2012
DOI:10.1016/j.apsusc.2012.03.058
Abstract
Poly(2-acrylamido-2-methylpropanesulfonic acid) (PAMPS) was grafted on the surface of carbon microspheres (CMSs), which were modified in prior by a mixed acid (HNO3 and H2SO4) oxidation and 3-methacryloxypropyl trimethoxysilane silanization. Then, the molecularly imprinting polymerization was carried out towards the macromolecule PAMPS grafted on the surface of CMSs using dibenzothiophene (DBT) as template, ethylene dimethacrylate as cross-linking agent and (NH4)2S2O8 (APS) as initiator to prepare surface molecularly imprinted polymer (MIP-PAMPS/CMSs) for adsorbing DBT. The optimized conditions of grafting PAMPS, including AMPS dosage, APS content, reaction temperature and reaction time, were emphasized in this paper. The morphology of the samples was characterized by field emission scanning electron microscopy. The functional groups were analyzed qualitatively by Fourier transform infrared spectrometry. The grafting degree of PAMPS was investigated by thermogravimetry. The results show that the preferable AMPS dosage, APS content, reaction temperature and time were 5 g, 0.15 g, 70 °C and 12 h, respectively, for preparing PAMPS/CMSs composite on the basis of 1.0 g of silanized-CMSs. The absorbing characteristic of MIP-PAMPS/CMSs toward DBT was studied preliminarily with dynamic adsorption. In the experiment of dynamic adsorption, MIP-PAMPS/CMSs and non-imprinted polymer (NIP-PAMPS/CMSs) were compared with respect to their rapid adsorption in 1 mmol/L of DBT solution in n-hexane. When the first 1 mL of 1 mmol/L DBT solution was injected and flowed through a column packed with 0.1 g of MIP-PAMPS/CMSs, the content of DBT reduced to 0.265 mmol/L, that is, decreased significantly from 279 to 74 ppm. When 3 mL of DBT solution was flowed through the packed column, the adsorption of MIP-PAMPS/CMSs toward DBT reached saturation with the maximum adsorption amount of 1.38 × 10−2 mmol/g and the overall adsorption efficiency of 46%, while NIP-PAMPS/CMSs adsorbed only 1.66 × 10−3 mmol/g of DBT. It is suggested that the MIP-PAMPS/CMSs had much better adsorption property towards DBT than NIP-PAMPS/CMSs.
Co-reporter:Xingmei Guo, Yongzhen Yang, Xuexia Zhao, Xuguang Liu
Applied Surface Science 2012 Volume 261() pp:159-165
Publication Date(Web):15 November 2012
DOI:10.1016/j.apsusc.2012.07.133
Abstract
Polymer/carbon spheres (CSs) composite materials, in which polymer was used as continuous phase and CSs as dispersed phase, were synthesized by in situ bulk polymerization. In order to improve CSs dispersibility in polymer matrix and compatibility with polymer matrix, the functional double bonds were introduced onto the surface of CSs by covalent and non-covalent method. Covalent functionalization was accompolished through mixed acid oxidation and subsequent reaction with acryloyl chloride. Field-emission scanning electron microscopy, Fourier-transform Infrared spectrometry and thermogravimetry were used to characterize the morphology, structure and effect of functionalization of CSs. Vinyl-functionalized CSs by acryloyl chloride were well dispersed in organic solvents, such as DMF, acetone and chloroform. Non-covalent functionalization by surfactant was accompolished by electrostatic interaction. Covalent and non-covalent functionalization enabled CSs to be homogeneously dispersed in poly(methyl methacrylate) (PMMA) matrix with good compatibility. These studies lay the foundation of preparing the non-close packed three-dimensional carbon-based photonic crystals.
Co-reporter:Mei Niu, Xuguang Liu, Jinming Dai, Wensheng Hou, Bingshe Xu
Progress in Organic Coatings 2012 Volume 74(Issue 3) pp:622-628
Publication Date(Web):July 2012
DOI:10.1016/j.porgcoat.2012.02.011
Wool fiber was modified by UV irradiation and then reacted with cross-linked chitosan-coated Ag-loading nano-SiO2 (CCTS-SLS) composites to prepare antibacterial wool fiber. The results show the topography of wool surface was also modified along with the formation of active radicals during UV irradiation. These active groups were used to graft antibacterial materials CCTS-SLS. Compared with parent wool fiber, the antibacterial wool fiber was improved in dyeing property. The dyeing uptake increased by 98% in a dyeing time of 50 min. Also, the antifelting performance increased as a result of the decrease in directional frictional effect after UV irradiation modification.Graphical abstractHighlights► UV irradiation could modify the topography of wool surface. ► The active radicals were formed to graft antibacterial materials. ► Dense antibacterial layer was coated on the wool substrate. ► The dyeing uptake was increased by 98% in a dyeing time of 50 min. ► The anti-felting property was added with the reduced directional frictional effect.
Co-reporter:Mei Niu, Xuguang Liu, Jinming Dai, Wensheng Hou, Liqiao Wei, Bingshe Xu
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2012 Volume 86() pp:289-293
Publication Date(Web):February 2012
DOI:10.1016/j.saa.2011.10.038
Wool fiber was modified by ultraviolet irradiation (UV) and functionalized by grafting antibacterial agent. The structure and properties of antibacterial wool fiber were discussed in detail. The secondary structure changes and crystal structure were analyzed based on Fourier Transformation Raman Spectrometry (FTR) and X-ray diffraction (XRD). The results show that the disordered degree of UV-treated sample was increased and the antibacterial sample became more oriented. Compared with parent wool fiber, the antibacterial wool fiber was improved in mechanical property. The force, tensile strength and elongation were increased by 18%, 16%, and 7%, respectively. Also, the anti-shrinkage performance was increased because of the decrease in the directional frictional effect (DFE).Graphical abstractHighlights► The structure changes of antibacterial wool have been analyzed by FTR and XRD. ► It showed that their structural changes had an important effect on their properties. ► The mechanical property was increased because of the improved molecular orientation. ► The anti-shrinkage property was raised because of grafting nano-antibacterial agent.
Co-reporter:Yongzhen Yang 杨永珍;Yanxing Han
Journal of Wuhan University of Technology-Mater. Sci. Ed. 2012 Volume 27( Issue 3) pp:454-458
Publication Date(Web):2012/06/01
DOI:10.1007/s11595-012-0484-5
Carbon-based films were synthesized by self-assembly of chitosan-encapsulated carbon microsphere (CMS@CS) composite. First, carbon microspheres (CMSs) prepared by chemical vapor deposition were modified by HNO3 and H2O2. Second, oxidized CMSs were modified by chitosan (CS). Finally, CMS@CS was self-assembled by vertical deposition, in which suspension concentration and deposition temperature on the quality of self-assembling film were investigated. Field emission scanning electron microscopy, atomic force microscopy, X-ray diffraction, thermogravimetry, and Fourier transformation infrared spectrometry were employed to characterize the morphology and structure of the samples. The results show that CMSs modified by CS had uniform particle size and good dispersion, CMS@CS was self-assembled into a dense film, the film thickened with increasing suspension concentration at fixed temperature, and more ordered film was obtained at 1 wt% of suspension concentration and 50 °C. The ultraviolet-visible absorption spectra show that the absorbance of CMS@CS film grew steadily with increasing suspension concentration and that the CMSs with oxygen-containing groups have a good assembling performance to form composite films with CS.
Co-reporter:Yongzhen Yang, Jingjing Song, Yanxing Han, Xingmei Guo, Xuguang Liu, Bingshe Xu
Applied Surface Science 2011 Volume 257(Issue 16) pp:7326-7329
Publication Date(Web):1 June 2011
DOI:10.1016/j.apsusc.2011.03.117
Abstract
SiO2 was firstly coated onto the surface of carbon microspheres (CMSs) using tetraethyl orthosilicate (TEOS) as precursor by Stöber method. Then SiO2-encapsulated CMS (CMS@SiO2) composites were self-assembled by vertical deposition, in which the effects of deposition temperature and suspension concentration on the quality of self-assembling film were investigated. Morphologies and structures of the samples were characterized by field emission scanning electron microscopy, Fourier transformation infrared spectrometry, X-ray diffraction and thermogravimetry. The results show that uniform CMS@SiO2 composites with good mono-dispersion were prepared by Stőber method with 0.5 g of CMSs, 2 mL of TEOS, 30 mL of ammonia and 12 h of reaction time, the CMSs-based films with ordered and denser structure were prepared by vertical deposition using CMS@SiO2 composites as monodipersion spheres under suspension concentration of 1 wt% and deposition temperature of 50 °C. The ultraviolet-visible absorption measurement shows that the absorbance of CMS@SiO2 composite films grew steadily with increasing suspension concentration.
Co-reporter:Xingmei Guo, Yongzhen Yang, Xuguang Liu
Applied Surface Science 2011 Volume 257(Issue 15) pp:6672-6677
Publication Date(Web):15 May 2011
DOI:10.1016/j.apsusc.2011.02.100
Abstract
Carbon spheres (CSs) were synthesized by chemical vapor deposition in Ar atmosphere using acetylene as carbon source. Vinyl-functionalized CSs was prepared by nitric acid oxidation and reacting with allylamine. The morphology, structure and effect of functionalization of CSs at different processing steps were characterized using field-emission scanning electron microscopy, Fourier-transform IR spectra, X-ray photoelectron spectroscopic and thermogravimetric analysis. The results show that some oxygen-containing groups such as carboxyl and hydroxyl were produced on the surface of CSs by nitric acid treatment, and vinyl groups were introduced on the surface of CSs by allylamine treatment. Acid-treated CSs are well dispersed in water and allylamine-treated CSs are well dispersed in organic solvent, which is preconditions of reactivity of CSs in liquid phase and lays the basis for the application of CSs.
Co-reporter:Liuqing Chen, Peng Tao, Chunyan Sun, Xuguang Liu, Bingshe Xu
Synthetic Metals 2011 Volume 161(11–12) pp:1145-1149
Publication Date(Web):June 2011
DOI:10.1016/j.synthmet.2011.02.004
2-Methyl-8-quinolinol reacted with salicylaldehyde to give the corresponding substituted 2-styryl-8-quinolinol. Two schemes were adopted in order to prepare zinc quinolates complex through styryl substitution in 2-position. In Scheme 1, four steps were used including hydrolysis of acetoxy, and single crystal of product of this step was acquired. For Scheme 2, acetoxy exchange reaction was directly used to give Zn complex from the styryl derivative a and Zn(OAc)2 in the presence of ethanol and triethylamine, which is a more facile synthesis method of zinc quinolates through styryl substitution in 2-position. The spectroscopic, thermal and optical properties of Zn complex were investigated. The thermal stability of Zn complex was higher than that of styryl derivative a. The residue yield at 800 °C in N2 for Zn complex was 64.3% whereas that for styryl derivative a was almost zero. Solutions of Zn complex in THF emitted yellow light with photoluminescence (PL) maximum at 551 nm, which is considerably red-shifted relative to Znq2 (535 nm) and Zn(2-Meq)2 (515 nm). The ground- and excited-state geometries, charge distributions, and excitation energies of Zn complex were evaluated by ab initio calculations.
Co-reporter:Yongzhen Yang, Xuguang Liu, Husheng Jia, Bingshe Xu
Materials Chemistry and Physics 2011 Volume 126(1–2) pp:424-431
Publication Date(Web):15 March 2011
DOI:10.1016/j.matchemphys.2010.10.044
During the experiments aimed at understanding the evolution mechanism by which vapor grown carbon nanofibers (VGCNFs) nucleate and grow, a series of carbon nanomaterials were synthesized by chemical vapor deposition (CVD) using deoiled asphalt (DOA) as carbon source and ferrocene as catalyst precursor with an experimental strategy developed to quench the CVD at different deposition times (3–30 min). The morphology and microstructure of the products were investigated by field emission scanning electron microscope, high resolution transmission electron microscope and X-ray powder diffractometer. The formation of hollow/metal-encapsulating carbon nanoparticles at short deposition time (3 min) of CVD and the subsequent evolution of these nanoparticles into carbon nanotubes/nanofibers at longer deposition time suggest a multi-step growth model for VGCNFs, which includes the stages of (1) pyrolysis and aggregation, (2) nucleation, coalescence and self-assembly, and (3) development and maturation. At first, C, Fe and Fe/C clusters are produced by decomposition and agglomeration of C and Fe species from the pyrolysis of DOA and ferrocene; second, the carbon nanoparticles are self-assembled into nanowires with dispersive metal nanoparticles, which are further developed into nanotubes for structural stability and minimum surface energy, meanwhile fishbone-like CNFs might be formed by rearranging carbon layers at an angle against the tube axis under the nucleation of small graphitic layers on certain crystal orientation of the metal particles; finally, CNFs are formed by the synergistic action of metal catalysis and continuous rearrangement of graphitic layers.Research highlights▶ A modified growth mechanism of carbon nanofibers was proposed. ▶ Growth process includes (1) pyrolysis and aggregation, (2) nucleation, coalescence and self-assembly and (3) deveplopment and maturation. ▶ The nucleation and rearrangement of graphitic layers depend on the crystal orientation of the metal nanoparticles.
Co-reporter:Yongzhen Yang, Xuguang Liu, Mingcong Guo, Sha Li, Weifeng Liu, Bingshe Xu
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2011 Volume 377(1–3) pp:379-385
Publication Date(Web):5 March 2011
DOI:10.1016/j.colsurfa.2011.01.032
The molecularly imprinted polymer (MIP) on the surface of carbon microspheres (CMSs), which were modified by acid and silylation treatment, was obtained by using dibenzothiophene (DBT) as template, methacrylic acid as functional monomer, ethylene glycol dimethacrylate as cross-linking agent and azoisobutyronitrile as initiator. Field emission scanning electron microscopy, Fourier transformation infrared spectroscopy and thermogravimetry were used to characterize the structure and morphology of the MIP-CMSs. The adsorption isotherm and kinetics of DBT on MIP-CMSs were investigated. The preliminary results show that MIP-CMSs possessed good recognition toward DBT, that is, the adsorption equilibrium time was about 5 h and the equilibrium adsorption amount was 0.595 mmol/g. The mechanism for adsorption of DBT onto MIP-CMSs was found to follow Langmuir isotherm and pseudo second order model.Graphical abstractResearch highlights► Molecularly imprinted polymer on carbon microsphere surfaces was obtained for adsorbing dibenzothiophene. ► The adsorption equilibrium time was ∼5 h and the equilibrium adsorption amount was 0.595 mmol/g. ► This novel surface molecular imprinted material with priority adsorption is of importance for deep desulfurization of oil. ► The adsorption mechanism followed Langmuir isotherm and pseudo second order model.
Co-reporter:Yongzhen Yang;Xingmei Guo;Hairong Wen
Journal of Nanoparticle Research 2011 Volume 13( Issue 5) pp:1979-1986
Publication Date(Web):2011 May
DOI:10.1007/s11051-010-9951-0
Nano-carbon materials were synthesized by the catalytic decomposition of acetylene at 420 °C using iron supported on sodium chloride as catalyst. The catalysts contain about 0.3, 1.6, 3.3, and 5.2 wt% iron. The samples were examined by scanning and transmission electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. The results show that nano onion-like fullerenes (NOLFs) surrounding an Fe3C core were obtained using the catalyst containing 0.3 wt% iron. These had a structure of stacked graphitic fragments, with diameters in the range 15–50 nm. When the product was further heat treated under vacuum at 1,100 °C, NOLFs with a clear concentric graphitic layer structure were obtained. The growth mechanism of NOLFs encapsulating metallic cores is suggested to be in accordance with a vapor–solid growth model.
Co-reporter:Yongzhen Yang, Xuguang Liu, Chun Yi Zhang, Mingcong Guo, Bingshe Xu
Journal of Physics and Chemistry of Solids 2010 Volume 71(Issue 3) pp:235-241
Publication Date(Web):March 2010
DOI:10.1016/j.jpcs.2009.11.012
A series of size-controllable carbon micro-spheres (CMSs) were synthesized from deoiled asphalt by chemical vapour deposition, with the emphasis on the effect of reaction temperature, Ar flow rate and collection zone. Graphitized carbon micro-spheres (GCMSs) were obtained from as-prepared CMSs by vacuum heat treatment at 2000 °C for 1 h. Air oxidation was performed to realize functionalization of CMSs. Morphologies and structures of CMSs and GCMSs were characterized by field emission scanning electron microscopy, high-resolution transmission electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and Raman spectroscopy, and the functional groups on the surface of GCMSs and CMSs were characterized by Fourier transformation infra-red spectrometry. Results show that effective mass production of size-controllable CMSs, with diameters ranging from 100 nm to 1 μm, was achieved. As-obtained high purity CMSs were spherical with uniform size and low graphitization degree, but the graphitization degree of GCMSs was enhanced obviously. By air oxidation, some oxygen-containing functional groups were introduced onto the surface of CMSs, while no functional groups were introduced onto the surface of GCMSs.
Co-reporter:Yong-zhen YANG, Xu-guang LIU, Qiu-ping LUO, Lin JIN, Bing-she XU
New Carbon Materials 2010 Volume 25(Issue 6) pp:431-437
Publication Date(Web):December 2010
DOI:10.1016/S1872-5805(09)60043-3
Co-reporter:Mei Niu;Jinming Dai;Husheng Jia;Liqiao Wei
Fibers and Polymers 2010 Volume 11( Issue 8) pp:1201-1203
Publication Date(Web):2010 December
DOI:10.1007/s12221-010-1201-7
Wool fiber was grafted with chitosan coated Ag-loading nano-SiO2 (CCTS-SLS) antibacterial composites under ultraviolet irradiation. The morphologies and structures of CCTS-SLS-wool were characterized by using scanning electronic microscopy, transmission electron microscopy, and Fourier transformation infrared spectrometry. The results show that a uniform and smooth antibacterial layer of 200 nm in thickness was formed on the surface of wool fiber by covalent bonding. The mechanical properties of the antibacterial wool fiber were improved. The antibacterial performance was found to be excellent, with antibacterial effect up to 90 % even after repeated washing. CCTS-SLS-wool possessed soft hand-feeling and good color.
Co-reporter:YongZhen Yang;WenFang Ren;Li Qiu;BingShe Xu
Science Bulletin 2010 Volume 55( Issue 33) pp:3838-3841
Publication Date(Web):2010 November
DOI:10.1007/s11434-010-4142-z
Bamboo-shoot-like oriented carbon micromaterials (BOCMs) were synthesized by a solvothermal method at 450°C for 4 h using deoiled asphalt (DOA) as carbon source, toluene as solvent, ferrocene as catalyst precursor and amphiphilic triblock copolymer P123 as surfactant. The morphology and structure of the products were characterized by X-ray diffraction, field emission scanning electron microscopy, high resolution transmission electron microscopy and Fourier transform infrared spectroscopy. The results reveal that the obtained products have good distribution with uniform diameters of about 0.5 μm and the lengths of 1–1.5μm, and hydrogen-carbon bonds are observed on the surface of BOCMs. The growth mechanism of BOCMs is discussed, in which that the catalysis of ferrocene and the dispersion and assembly of the aromatic molecules of DOA directed by P123 are critical to the formation of the BOCMs. The coercivity value (231.91 Oe) from the measurement of a vibrating sample magnetometer shows that the BOCMs have an obvious ferromagnetic behavior.
Co-reporter:Niu Mei, Liu Xuguang, Dai Jinming, Jia Husheng, Wei Liqiao, Xu Bingshe
Carbohydrate Polymers 2009 Volume 78(Issue 1) pp:54-59
Publication Date(Web):4 August 2009
DOI:10.1016/j.carbpol.2009.04.029
A crosslinked chitosan (CCTS) coated Ag-loading nano-SiO2 composite (CCTS–SLS) was prepared. The structures of CCTS–SLS were characterized by field emission scanning electron microscopy and X-ray photoelectron spectroscopy. The antibacterial properties of CCTS–SLS were measured as the minimal inhibitory concentration and the rate of bacterial growth. The experimental results indicate that the antibacterial activity of CCTS–SLS was affected by the mass ratio of SLS to chitosan, acetic acid concentration and crosslinking time. Moreover, CCTS–SLS exhibited high antibacterial activity against Escherichia coli and Staphylococcus aureus as a result of the coordinated action of CCTS and SLS.
Co-reporter:XuGuang Liu;CunJing Wang;YongZhen Yang;XingMei Guo
Science Bulletin 2009 Volume 54( Issue 1) pp:137-141
Publication Date(Web):2009 January
DOI:10.1007/s11434-008-0573-1
Nano-carbon materials were synthesized by the catalytic decomposition of acetylene at 400°C by using Fe/Al2O3 as catalyst. The product was refluxed in 36% concentrated HCl at 60. for 48 h in order to remove the catalyst support. The samples were examined by scanning and high resolution transmission electron microscopy, energy dispersive spectroscopy and X-ray diffraction. The results show that nano onion-like fullerenes encapsulating a Fe3C core were obtained. These had a structure of stacked graphitic fragments, with diameters ranging from 15–50 nm. When the product was further heattreated at 1100°C for 2 h, nano onion-like fullerenes with a clear concentric graphitic layer structure were obtained. The growth mechanism of nano onion-like fullerenes encapsulating metal cores is suggested to follow a vapor-solid growth model.
Co-reporter:Xingmei Guo, Xuguang Liu, Bingshe Xu, Tao Dou
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2009 Volume 345(1–3) pp:141-146
Publication Date(Web):5 August 2009
DOI:10.1016/j.colsurfa.2009.04.048
Carbon sphere-silica core–shell structured material was prepared in the presence of cetyltrimethylammonium bromide using tetraethyl orthosilicate as precursor of silica by a sol–gel method combined with Stöber method. Carbon sphere cores with an average diameter of 300 nm were prepared by the pyrolysis of acetylene. After carbon sphere cores were removed by calcinations, hollow silica spheres with smooth surface and uniform shell thickness around 110 nm were obtained. The core–shell structure of carbon sphere-silica composites and the hollow structure of silica spheres were characterized by FESEM, HRTEM, XRD, XPS and FTIR. The results indicate that the silica was coated on the surface of carbon spheres. The inner diameter of the hollow silica spheres with amorphous shell was about 290 nm. A possible formation mechanism of the core–shell structure of carbon sphere-silica and hollow silica spheres was proposed.
Co-reporter:A.-B. Du, X.-G. Liu, D.-J. Fu, P.-D. Han, B.-S. Xu
Fuel 2007 Volume 86(1–2) pp:294-298
Publication Date(Web):January 2007
DOI:10.1016/j.fuel.2006.05.031
Onion-like fullerenes (OLFs) were synthesized in high yields from coal by radio frequency plasma. The morphologies and structures of the products were characterized by high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) technique. Results reveal that OLFs can be prepared from coal with high purity. The particles display a clear polyhedral or quasi-spherical morphology with hollow center, having an average diameter ranging from 10 nm to 35 nm and high degree of graphitization.
Co-reporter:Zhi Yang, Yu-Long Ji, Guoqiang Lan, Li-Chun Xu, Xuguang Liu, Bingshe Xu
Solid State Communications (September 2015) Volume 217() pp:38-42
Publication Date(Web):1 September 2015
DOI:10.1016/j.ssc.2015.05.013
Highlights•Full-boron fullerene B40 was applied to design molecular device.•Large rectification ratio was observed in the molecular device.•The molecular device has excellent optical properties and can be used as photodetector.All-boron fullerene B40 is a highly stable molecule, which has been successfully synthesized in recent experiment. In this paper, with Au as two electrodes, the single-molecule device Au–B40–Au was investigated by using density functional theory and non-equilibrium Green׳s function method. The results show that the device can exhibit large rectification ratio and significant negative differential resistance. More importantly, the photocurrent of the device has different responses in the infrared, visible and ultraviolet regions. The excellent optoelectronic properties ensure that the device can be used as photodetector.
Co-reporter:Feifei Duan, Chaoqiu Chen, Xiaofeng Zhao, Yongzhen Yang, Xuguang Liu and Yong Qin
Environmental Science: Nano 2016 - vol. 3(Issue 1) pp:NaN222-222
Publication Date(Web):2016/01/04
DOI:10.1039/C5EN00198F
Water-compatible molecularly imprinted polymers (MIPs) with dual monomer–template interactions were synthesized via the synergy of bi-functional monomers of water-soluble 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and styrene (St) for the selective adsorption of bisphenol A (BPA) from aqueous media using porous graphene oxide as a support. Both hydrogen bonds and π–π interactions are responsible for the adsorption of BPA on the synthesized MIPs. The formation and structure of the MIPs are verified by Fourier transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy and dispersion analysis in water. The adsorption results show that the adsorption capacity of MIPs is greatly enhanced by virtue of the synergy of AMPS and St. The MIPs prepared with a molar ratio (AMPS:St) of 2.5:2.5 exhibit the highest adsorption capacity (up to 85.7 mg g−1 at 293 K) toward BPA in aqueous media. The kinetics and isotherm data can be well fitted with the pseudo-second-order kinetic model and the Freundlich isotherm, respectively. Competitive adsorption experiments demonstrate that the synthesized MIPs display excellent selectivity toward BPA against analogue molecules. The MIPs show good recoverability and exhibit excellent adsorption affinity toward BPA even in complex river water. This work provides a versatile approach for the fabrication of high performance MIPs for application in aqueous environments.
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