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Capacitance and voltage matching between MnO2 nanoflake cathode and Fe2O3 nanoparticle anode for high-performance asymmetric micro-supercapacitors

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Nano Research 2017年第7期10卷 2471-2481页

作者： Zehua Liu Xiaocong Tian Xu Xu Liang He Mengyu Yan Chunhua Han Yan Li Wei Yang Liqiang Mai State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China Department of Chemistry University of California Berkeley CA 94720 USA

Planar micro-supercapacitors show great potential as the energy storage unit in miniaturized electronic devices. Asymmetric structures have been widely inves- tigated in micro-supercapacitors, and carbon-based materials are commonly applied in the electrodes. To integrate different metal oxides in both electrodes in micro-supercapacitors, the critical challenge is the pairing of different faradic metal oxides. Herein, we propose a strategy of matching the voltage and capadtance of two faradic materials that are fully integrated into one high-performance asymmetric micro-supercapacitor by a facile and controllable fabrication process. The fabricated micro-supercapacitors employ MnO2 as the positive active material and Fe203 as the negative active material, respectively. The planar asymmetric micro-supercapacitors possess a high capacitance of 60 F-cm-3, a high energy density of 12 ***-3, and a broad operation voltage range up to 1.2 V.

关键词： MnO2 nanoflake Fe2O3 nanoparticle asymmetric electrodes micro-supercapacitors

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Microstructure and Electrical Conductivity of CNTs/PMMA Nanocomposite Foams Foaming by Supercritical Carbon Dioxide

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Journal of Wuhan University of technology(materials Science) 2016年第2期31卷 481-486页

作者：袁欢熊远禄罗国强 LI Meijuan SHEN Qiang ZHANG Lianmeng State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology School of Chemistry Chemical Engineering and Life ScienceWuhan University of Technology

The carbon nanotubes（CNTs）/polymethylmethacrylate（PMMA）nanocomposite foams were prepared by the anti-solvent precipitation and supercriticalfoaming *** morphology and the electricalconductivity of the foams with different kinds of CNTs were *** experimentalresults showed that allthe foams had uniform cellstructure,and the cellsize changed from 1.9 to 10 μm when the foaming temperature ranged from 50 ℃ to 95 ℃.With smallcellsize（1.9-4.0 μm）,the conductivities of the foams were 3.34×10^（-6）-4.16×10^（-6） S/cm compared with the solid matrix since the introduction of micro cells did not destroy the conductive ***,when the cellsize was biger（4.5-10 μm）,the aspect ratio of the CNTs played the dominant role of the *** foams with short CNTs had higher conductivity,since the short CNTs were hard to stretch and snap by the cells and can well-dispersed in the cellwalland *** results of this work provided a novelmaterialdesign method for conductive foams based on the rule of both microstructure and aspect ratio of the CNTs.

关键词： electrical conductivity CNTs supercritical foaming nanocomposite foams

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New approach for chiral separation: from polysaccharide-based materials to chirality-responsive polymers

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Science China Chemistry 2014年第11期57卷 1492-1506页

作者： DING Peng CHANG BaiSong QING GuangYan SUN TaoLei State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology School of Chemistry Chemical Engineering and Life Science Wuhan University of Technology

Chiral separation that is closely related to daily life is a meaningful research. Polysaccharide-(e.g., cellulose, amylose derivatives) based chiral packing materials afford powerful chiral stationary phases(CSPs) toward a broad range of racemic compounds. However, considering the explosive growth of specific chiral drugs, the separation efficiencies of these CSPs need further improvement, which calls for new approaches and strategies. Smart polymers can change their physical or chemical properties dynamically and reversibly according to the external stimuli(e.g., thermo-, pH, solvent, ion, light, critical parameters for chromatographic separation) exerted on them, subsequently resulting in tunable changes in the macroscopic properties of materials. In addition to their excellent controllability, the introduction of chiral characteristics into the backbones or side-chains of smart polymers provides a promising route to realize reversibly conformational transition in response to the chiral analytes. This dramatic transition may significantly improve the performance of materials in chiral separation through modulating the enantioselective interactions between materials and analytes. With the help of chirality-responsive polymers, intelligent and switchable CSPs could be developed and applied in column-liquid chromatography. In these systems, the elution order or enantioselectivity of chiral drugs can be precisely modulated, which will help to solve many challenging problems that involve complicated enantiomers. In this paper we introduce some typical examples of smart polymers that serve as the basis for a discussion of emerging developments of CPSs, and then briefly outline the recent CSPs based on natural and certain synthetic polymers.

关键词： chiral separation chiral stationary phases（CSPs） enantioseparation HPLC smart polymer

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Preparation of high emissivity NiCr_2O_4 powders with a spinel structure by spray drying

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International Journal of Minerals,Metallurgy and materials 2012年第2期19卷 173-178页

作者： Xu-dong Cheng Jie Min Zhen-qi Zhu Wei-ping Ye State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China School of Materials Science and Technology Wuhan University of Technology Wuhan 430070 China

Spray-drying was used to produce the high emissivity NiCr2O4 powders with a spinel structure. Preliminary investigations focused on fabricating the high emissivity powders for infrared radiation coatings and finding the relationship between microstructure and emissivity. The NiCr2O4 powders were characterized for composition, microstructure, and infrared emissivity by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, infrared radiant instrument, and Fourier transform infrared spectra （FT-IR）. Thermogravimetry and differential thermal analysis show that the appropriate baking temperature for NiCr2O4 powder preparation is about 1200？C. The emissivity measurement and FT-IR spectra show that, because of the special spinel structure, the NiCr2O4 powders have a high emissivity about 0.91. Spray-drying is a suitable method to produce the high emissivity ceramic powders.

关键词： emissivity infrared radiation spray drying powders ceramic materials nickel compounds chromium compounds

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Bio-inspired high-efficiency photosystem by synergistic effects of core-shell structured Au@CdS nanoparticles and their engineered location on{001}facets of SrTiO_(3)nanocrystals

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Journal of materials Science & technology 2023年第5期136卷 159-168页

作者： Wenxuan Wang Wenhao Chi Zhaoyong Zou Pengchao Zhang Kun Wang Ji Zou Hang Ping Jingjing Xie Weimin Wang Zhengyi Fu State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China Hubei Longzhong Laboratory Xiangyang 441000China State Key Laboratory of Silicate Materials for Architectures Wuhan University of TechnologyWuhan 430070China

Natural photosynthesis,which provides a green and high-efficiency energy conversion path by spatial separation of photogenerated carriers through combined actions of molecules ingeniously arranged in an efficient solar nanospace,highlights the importance of rational nanostructure design to realize artificial high-efficiency *** by these unique features,we constructed a high-efficiency ternary photosystem by selectively decorating the{001}facets of 18-facet SrTiO_(3)with Au@CdS photosensitizers via a green photo-assisted *** from the dual-facilitated charge carriers transportation in core-shell structured Au@CdS heterojunction and well-faceted 18-facet SrTiO_(3)nanocrystal,such a photo-catalyst could realize the effective spatial separation of photogenerated electrons and *** expected,the 18-facet SrTiO_(3)/Au@CdS photocatalyst exhibits superior activity in visible-light-driven photocatalytic hydrogen evolution(4.61 mmol h^(−1)g^(−1)),166%improvement in comparison with randomly deposited Au@CdS(1.73 mmol h^(−1)g^(−1)).This work offers new insight into the development of green and high-efficiency photocatalytic systems based on the rational nanostructure design by crystal facet engineering.

关键词： Au@CdS composites Core-shell 18-facet SrTiO_(3) Photogenerated carrier separation Crystal facet engineering Hydrogen production

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Preparation of TiO_(2) Supported Mxene Catalyst for High Efficiency Hydrogen Production

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Journal of Wuhan University of technology(materials Science) 2023年第2期38卷 286-291页

作者： HU Mei XIN Jin LIU Zhenyu ZENG Hui WANG Yanze Wuhan Institute of Marine Electric Propulsion Wuhan430064China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan430070China

We studied a method to prepare a novel titanium dioxide(TiO_(2))composite photocatalyst,starting from improving the separation efficiency of photogenerated electrons and *** TiO_(2)microspheres were prepared by sol-gel method and loaded onto Ti3C2Tx(Mxene).The high electrical conductivity of Mxene was utilized to transfer photogenerated electrons quickly and effectively prevent their *** adjusting the addition amount of Mxene,the hydrogen production efficiency of the sample was greatly improved,and the maximum efficiency reached 135.2μmol·g^(-1)·h^(-1),which was twice that of pure TiO_(2).The nanocomposites were characterized by XRD,PL,TEM and SEM analysis and electrochemical methods,and the test proved that the improvement of hydrogen production efficiency was caused by the improvement of the separation efficiency of photogenerated electrons and *** work demonstrates the application of Mxene as a catalyst to improve efficiency and broadens the application prospects of Mxene.

关键词： TiO_(2) Mxene hydrogen production photocatalysis

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Mg-Based Micromotors with Motion Responsive to Dual Stimuli

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Research 2020年第1期2020卷 966-977页

作者： Kang Xiong Leilei Xu Jinwei Lin Fangzhi Mou Jianguo Guan State Key Laboratory of Advanced Technology for Materials Synthesis and Processing International School of Materials Science and EngineeringWuhan University of TechnologyWuhan 430070China

Mg-based micromotors have emerged as an extremely attractive artificial micro/nanodevice,but suffered from uncontrollable propulsion and limited motion lifetime,restricting the fulfillment of complex ***,we have demonstrated Mg-based micromotors composed of Mg microspheres asymmetrically coated with Pt and temperature-sensitive poly(N-isopropylacrylamide)(PNIPAM)hydrogel layers in *** can implement different motion behaviors stemming from the driving mechanism transformation when encountering catalyzed substrates such as H_(2)O_(2) and respond to both H_(2)O_(2) concentration and temperature in aqueous *** as-constructed Mg-based micromotors are self-propelled by Pt-catalyzed H_(2)O_(2) decomposition following the self-consuming Mg-H_(2)O *** this case,they could further generate bilateral bubbles and thus demonstrate unique self-limitation motion like hovering when the phase transformation of PNIPAM is triggered by decreasing temperature or when the H_(2)O_(2) concentration after permeating across the PNIPAM hydrogel layer is high enough to facilitate bubble *** work for the first time provides a stimuli-induced“hovering”strategy for self-propelled micromotors,which endows Mg-based micromotors with an intelligent response to the surroundings besides the significant extension of their motion lifetime.

关键词： transformation consuming attractive

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SC-IrO_2 NR-carbon hybrid:A catalyst with high electrochemical stability for oxygen reduction

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Science China Chemistry 2013年第1期56卷 131-136页

作者： WANG GuangJin CHENG Feng YU Yi LIANG Cong XU Tian PAN Mu State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Hubei Provincial Key Laboratory of Fuel Cell

The enhanced electrochemical stability of the synthesized hybrid catalyst has been demonstrated by the introduction of the synergistic effect between carbon powder additive and the prepared *** crystal IrO 2 nanorod (SC-IrO 2 NR) catalyst was prepared by a sol-gel *** structure and performance of the catalyst sample were characterized by X-ray diffraction spectroscopy (XRD),scanning electron microscope (SEM),transmission electron microscope (TEM),rotating disk electrode (RDE) and cyclic voltammetry (CV) *** patterns and TEM images indicate that the catalyst sample has a rutile IrO 2 single crystal nanorod *** onset potential for oxygen reduction reaction (ORR) of the SC-IrO 2 NR-carbon hybrid catalyst specimen is 0.75 V (***) in RDE *** and RDE test results show that the SC-IrO 2 NR-carbon hybrid catalyst has a better electrochemical stability in comparison with the commercial Pt/C catalyst,with attenuation ratios of 17.67% and 44.60% for the SC-IrO 2 NR-carbon hybrid catalyst and the commercial Pt/C catalyst after 1500 cycles,***,in terms of stability,the SC-IrO 2 NR-carbon hybrid catalyst has a promising potential in the application of the proton exchange membrane fuel cell.

关键词： single crystal nanorods IrO 2 electrochemical stability oxygen reduction reaction

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Improved distortion prediction in additive manufacturing using an experimental-based stress relaxation model

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Journal of materials Science & technology 2020年第24期59卷 83-91页

作者： Ruishan Xie Qingyu Shi Gaoqiang Chen State Key Laboratory of Tribology Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China Key Laboratory for Advanced Material Processing Technology Ministry of EducationBeijing 100084China

In additive manufacturing(AM),numerous thermal cycles make stress relaxation a significant factor in affecting the material mechanical ***,the traditional material constitutive model cannot describe repeated annealing ***,we propose an improved constitutive model based on a serial of stress relaxation experiments,which can descript the temperature and time-dependent stress relaxation behavior during *** using the proposed relaxation model,the prediction accuracy is significantly improved due to the recovery of inelastic strain during multilayer *** results are validated by both in-situ and final distortion *** influence mechanism of the relaxation behavior on material mechanical response is explained by the three-bar model in thermo-elastic-plastic *** relaxation behavior during the whole AM process is *** stress behavior is found to have a limited effect when merely depositing several layers;nevertheless,it becomes a prominent impact when depositing multiple *** proposed model can enhance modeling accuracy both in AM and in multilayer welding.

关键词： Additive manufacturing Welding Thermo-mechanical modeling Distortion prediction Stress relaxation

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Rapid growth of ZnO hexagonal tubes by direct microwave heating

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International Journal of Minerals,Metallurgy and materials 2010年第1期17卷 80-85页

作者： Zhen-qi Zhu Jian Zhou School of Materials Science and Technology Wuhan University of Technology Wuhan 430070 China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China

Zinc oxide hexagonal tubular crystals were synthesized by direct microwave heating from ZnO powders within 5 min without any metal catalysts or transport agents. ZnO source materials were evaporated from the high-temperature zone in an enclosure, and crystals were grown on the self-source substrate in an appropriate condition. The ZnO vapor formed in the high-temperature zone can deposit and grow on the powders located in the low-temperature zone to form crystals. The scanning electron microscopy （SEM） reveals that these products are hexagonal tube crystals with 80 ~rn in diameter and 250 μm in length, having a well faceted end and side surface. A possible growth mechanism and the influence of reaction temperature on the formation of crystalline ZnO hexagonal tubes were presented. The photoluminescence （PL） exhibits strong ultraviolet emission at room temperature, indicating the potential applications in short-wave light-emitting photonic devices.

关键词： ZnO crystal microwave heating vapor growth photoluminescence （PL）

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