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Chemical equilibrium controlled synthesis of polyoxymethylene dimethyl ethers over sulfated titania

Journal of Energy Chemistry 2015年第2期24卷 239-244页

作者： Huaju Li Huanling Song Feng Zhao Liwei Chen Chungu Xia Laboratory for Nano-Catalytic Material & Technology Division of Advanced Nano?materials Suzhou Institute of Nano-Tech and Nano-BionicsChinese Academy of Sciences State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical Physics Chinese Academy of Sciences i-Lab Suzhou Institute of Nano-Tech and Nano-Bionics Chinese Academy of Sciences

The chemical equilibrium and reaction kinetic behavior in the synthesis of polyoxymethylene dimethyl ethers （DMMn） were investigated over sulfated titania in order to reveal the decisive factor controlling the reaction. The results showed that the molar ratio of adjacent DMMn products in equilibrium solution had the same value, which depended absolutely on the reaction temperature. Meanwhile, the reactions had the same DMMn products distributions under varied reaction conditions. The equilibrium constants of the related step-wise reactions for DMMn formation were equal, which were calculated based on the bulk compositions of the reaction solution. And thus, the selectivity to DMMn was mainly controlled by the chemical equilibrium, i.e., thermodynamic control. In brief, the present results provide some guidance for future synthesis of DMMn.

关键词： polyoxymethylene dimethyl ethers sulfated titania chemical equilibrium reaction kinetic molar ratio

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Preparation of K2Ti4O9 nanowhiskers via stearic acid method

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materials Research Innovations 2015年 19卷 340-344页

作者： Zhang, S. Wu, J. Ji, X.L. Yi, F. Hu, P.F. State Key Laboratory of Advanced Technology for Material Synthesis and Processing Wuhan University of Technology 122 Luoshi Road Wuhan430070 China Shool of Materials Science and Engineering Wuhan University of Technology 122 Luoshi Road Wuhan430070 China

K2Ti4O9 nanowhiskers were synthesised via stearic acid method by using potassium hydroxide (KOH) and tetrabutyl titanate (Ti(OC4H9)4) as raw materials. The effects of molar ratio of tetrabutyl titanate and KOH (RT/K), calcination temperature (TC) on composition, morphology of products have been investigated. RT/K showed a significant effect on length to diameter ratio (RL/D) of the nanowhiskers. K2Ti4O9 nanowhiskers with RL/D greater than 20 were prepared at RT/K = 1 and TC = 850°C. Reaction mechanism of K2Ti4O9 nanowhiskers also has been studied. © 2015 W. S. Maney & Son Ltd.

关键词： Titanium compounds

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Applications of hierarchically structured porous materials from energy storage and conversion, catalysis, photocatalysis, adsorption, separation, and sensing to biomedicine

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Chemical Society reviews 2016年第12期45卷 3479-563页

作者： Ming-Hui Sun Shao-Zhuan Huang Li-Hua Chen Yu Li Xiao-Yu Yang Zhong-Yong Yuan Bao-Lian Su State Key Laboratory of Advanced Technology for Material Synthesis and Processing Wuhan University of Technology Luoshi Road 122 Wuhan 430070 China. chenlihua@*** baoliansu@***. Collaborat Innovat. Ctr. Chem. Sci. & Engn. Tianjin Key Lab. Adv. Energy Mat. Chem. Minist. Educ. Coll. Chem. Nankai Univ. Tianjin 300071 China. State Key Laboratory of Advanced Technology for Material Synthesis and Processing Wuhan University of Technology Luoshi Road 122 Wuhan 430070 China. chenlihua@*** baoliansu@*** and Laboratory of Inorganic Materials Chemistry (CMI) University of Namur 61 rue de Bruxelles B-5000 Namur Belgium. bao-lian.su@unamur.be and Clare Hall University of Cambridge Cambridge CB2 1EW UK. bls26@cam.ac.uk.

Over the last decade, significant effort has been devoted to the applications of hierarchically structured porous materials owing to their outstanding properties such as high surface area, excellent accessibility to active sites, and enhanced mass transport and diffusion. The hierarchy of porosity, structural, morphological and component levels in these materials is key for their high performance in all kinds of applications. The introduction of hierarchical porosity into materials has led to a significant improvement in the performance of materials. Herein, recent progress in the applications of hierarchically structured porous materials from energy conversion and storage, catalysis, photocatalysis, adsorption, separation, and sensing to biomedicine is reviewed. Their potential future applications are also highlighted. We particularly dwell on the relationship between hierarchically porous structures and properties, with examples of each type of hierarchically structured porous material according to its chemical composition and physical characteristics. The present review aims to open up a new avenue to guide the readers to quickly obtain in-depth knowledge of applications of hierarchically porous materials and to have a good idea about selecting and designing suitable hierarchically porous materials for a specific application. In addition to focusing on the applications of hierarchically porous materials, this comprehensive review could stimulate researchers to synthesize new advanced hierarchically porous solids.

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Mechanical alloying and spark plasma sintering of CoCrFeNiMnAl high-entropy alloy

Mechanical alloying and spark plasma sintering of CoCrFeNiMn...

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作者： Wang, Chao Ji, Wei Fu, Zhengyi Department of Architecture and Material Engineering Hubei University of Education Wuhan430205 China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan430070 China

An equiatomic CoCrFeNiMnAl high-entropy alloy was synthesized by mechanical alloying, and alloying behaviors, microstructure and annealing behaviors were investigated. It was found that a solid solution with refined microstructure of 20 nm in grain size could be obtained after 30 h milling. As-milled powder transformed into a face-centered cubic phase above 500 °C. The as-milled powder was subsequently consolidated by spark plasma sintering at 800 °C, BCC phase and FCC phase coexisted in the consolidated HEA, which had excellent properties in Vickers hardness of 662 HV and compressive strength of 2142 MPa. © 2014 The Society of Powder technology Japan. Published by Elsevier B.V. and The Society of Powder technology Japan. All rights reserved.

关键词： Mechanical alloying

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Graphene-based composite photocatalyst for solar fuel production

Graphene-based composite photocatalyst for solar fuel produc...

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中国化学会第29届学术年会

作者： Jiaguo Yu State Key Laboratory of Advanced Technology for Material Synthesis and Processing Wuhan University of Technology

The production of solar fuels by solar energy conversion is considered to be one of major strategies for solving the global energy and environmental problems in the future. Photocatalytic water splitting for H2 production and CO2 reduction for methane formation have become important and promising methods for clean, economical, and renewal production of solar fuels by using solar light since Fujishima and Honda first reported the photoelectrochemical water splitting on a TiO2 electrode in 1972. Among various semiconductors, titania(TiO2) has attracted special attention because of its strong oxidizing and reduction power, cost effectiveness, lack of toxicity, and high photochemical corrosive resistance. Usually, the photocatalytic H2-production activity on TiO2 is significantly dependent on the type and amount of co-catalyst because bare TiO2 has poor photocatalytic H2-Production activity. It is well-known that the loading of Pt as a co-catalyst on TiO2 significantly enhances H2-production activity for photocatalytic water splitting in the presence of sacrificial reagents. However, Pt is a rare and expensive noble metal. Therefore, alternative co-catalysts based on non-precious metals and earth-abundant materials have been actively pursued. Graphene-based nanocpmposite photocatalysts have recently caused tremendous interest as a viable alternate to increase photocatalytic H2-production and CO2-reduction performance in converting solar energy into chemical energy. The use of graphene as cocatalyst and support to enhance the H2-production activity of photocatalysts has been confirmed due to its unique two-dimensional conjugated structure and electronic properties. In this talk, I will present our recent work on the design and fabrication of graphene-based nanocomposite photocatalytic materials for H2 production and CO2 reduction. The rational designs for high-performance photocatalytic materials using graphene-based materials are described. Our work also demonstrates gr

关键词： Graphene-based composite photocatalyst for solar fuel production

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Design and fabrication of semiconductor photocatalyst for photocatalytic reduction of CO_2 to solar fuel

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Science China materials 2014年第1期57卷 70-100页

作者：李鑫温九青刘敬祥方岳平余家国 State Key Laboratory of Advanced Technology for Material Synthesis and Processing Wuhan University of Technology College of Science South China Agricultural University Department of Physics Faculty of Science King Abdulaziz University

The shortage of fossil fuels and the disastrous pollution of the environment have led to an increasing interest in artificial photosynthesis. The photocatalytic conversion of CO2 into solar fuel is believed to be one of the best methods to overcome both the energy crisis and environmental problems. It is of significant importance to efficiently manage the surface reactions and the photo-generated charge carriers to maximize the activity and selectivity of semiconductor photocatalysts for photoconversion of CO2 and H2 O to solar fuel. To date, a variety of strategies have been developed to boost their photocatalytic activity and selectivity for CO2 photoreduction. Based on the analysis of limited factors in improving the photocatalytic efficiency and selectivity, this review attempts to summarize these strategies and their corresponding design principles, including increased visible-light excitation, promoted charge transfer and separation, enhanced adsorption and activation of CO2, accelerated CO2 reduction kinetics and suppressed undesirable reaction. Furthermore, we not only provide a summary of the recent progress in the rational design and fabrication of highly active and selective photocatalysts for the photoreduction of CO2, but also offer some fundamental insights into designing highly efficient photocatalysts for water splitting or pollutant degradation.

关键词： CO2 二氧化碳光催化剂 Ti

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Impedance analysis of Nb2O5 doped BaTiO3-Na0.5Bi0.5TiO3 ceramics

Impedance analysis of Nb2O5 doped BaTiO3-Na0.5Bi0.5TiO3 cera...

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IEEE International Symposium on Applications of Ferroelectrics (ISAF)

作者： Yue Sun Hanxing Liu Hua Hao Shujun Zhang State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan China Material Research Institute The Pennsylvania State University USA

BaTiO 3 -based MLCC materials were limited for high temperature applications (temperature range up to 200°C), due to their low Curie temperatures. The addition of Na 0.5 Bi 0.5 TiO 3 (NBT) component in BaTiO 3 (BT) based ceramics was found to increase the Curie temperature, without sacrificing the dielectric constant. The Curie temperature was reported to increase from 125°C to 156°C with addition up to 10mol%, making it possible to satisfy the X8R or X9R criterions. In addition, the small amount of Nb 2 O 5 dopant in the system leads to a diffused dielectric maxima and improved temperature stability. The NBT-BT with 2wt% Nb 2 O 5 addition was found to exhibit a core-shell structure, while maintaining the dielectric constant at about 2500. To analyze the electrical microstructure variation, the obtained impedance data was fitted by a 4RC equivalent circuit, corresponding to the core, shell, grain boundary, and ceramic/electrode interface regions. All the electrical properties, including the capacitance, activation energy, and conductivity could be well explained by using this equivalent circuit.

关键词： Niobium Ceramics Grain boundaries Dielectrics Impedance Temperature Conductivity

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HIERARCHICALLY POROUS STRUCTURED materialS AND THEIR ENHANCED CATALYTIC ACTIVE STABILITY

HIERARCHICALLY POROUS STRUCTURED MATERIALS AND THEIR ENHANCE...

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10th IUPAC International Conference on Novel materials and their synthesis NMS-X(IUPAC第十届新材料及其合成国际会议)

作者： A.YONG WANG B.WEI GENG C.RU-JIN CHENG D.NAN JIANG E.XIAO-YU YANG F.BAO-LIAN SU Laboratory of Inorganic Materials Chemistry University of Namur (FUNDP)61 Rue de BruxellesB-5 000 NamurBelgium State Key Laboratory of Advanced Technology for Material Synthesis and Processing Wuhan University of TechnologyLuoshi Road 122430070 WuhanChina State Key Laboratory of Advanced Technology for Material Synthesis and ProcessingWuhan University of TechnologyLuoshi Road 122430070 WuhanChina

As a hot topic in recent years, hierarchically porous structured materials have received plenty of attentions and lots of work has been done on their synthesis. For their outstanding properties, hierarchically porous structured materials have attractively potential applications in catalysis, controlled release, biomedicine, separation science and energy. We have synthesized several micro-meso-macro hierarchically porous structured materials through different methods. Except for some general characteristics of porous structured materials, these materials possess some common superiorities, and the highlight is that they have highly interconnected network of well-defined macropores with uniform mesoporosity and zeolitic micro-channels which can lead to highly active sites, larger external surface areas and fast diffusion of species. We applied these hierarchically porous structured materials to catalysis by encapsulating active species into macropores, such as enzymes,metallic oxide nanoparticles and metallic ion, which exhibite high catalytic activity, long-term stability, and excellent recycling behaviour. Hierarchically porous structured materials applied to catalysis are obviously more attractive and promising than tradition catalysts. What's more, other advanced properties can be exploited in the design of magnetic devices, sensors, and biofuel cell etc. which are based on hierarchically porous structured materials.

关键词： micro-meso-macro porous materials catalyst long-term stability

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Preparation and study of 0.7(Mg0.8Zn0.2)TiO3·0.3{Ba4Nd28/3Ti18O54·zBi2O3} microwave dielectric ceramics

Preparation and study of 0.7(Mg0.8Zn0.2)TiO3·0.3{Ba4Nd28/3T...

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12th China International Nanoscience and technology Symposium, and the Nano-Products Exposition, CINSTS 2013

作者： Ji, Xiao Li Zhai, Cheng Cheng Zhang, Song State Key Laboratory of Silicate Materials for Architectures Wuhan University of Technology 122 Luoshi Road Wuhan 430070 China State Key Laboratory of Advanced Technology for Material Synthesis and Processing Wuhan University of Technology 122 Luoshi Road Wuhan 430070 China

ISBN: (纸本)9783038350569

The (Mg0.8Zn0.2)TiO3(MZT) as the foundation is mainly studied to join high dielectric material Ba4Nd28/3Ti18O54·zBi2O3(BNT) to preparation microwave dielectric ceramic 0.7(Mg0.8Zn0.2)TiO3·0.3{Ba4Nd28/3Ti18O54·zBi2O3}(z=0.15, 0.18, 0.2) to improve dielectric properties of MZT. While Bi3+ could reduce the sintering temperature to make MZT and BNT composite in a lower sintering temperature (1200~1230 °C). According to the results of the dielectric properties, density, XRD and SEM tests of the obtained ceramics, we can find out that the amount of doped Bi3+ and the sintering temperature affected the structure and properties of the ceramics. The results show that when z=0.18, 0.7(Mg0.8Zn0.2)TiO3·0.3{Ba4Nd28/3Ti18O54·zBi2O3} sintering at 1230°C can get good dielectric properties: Εr =35.56, Qf =5811GHz, τf =-3.225 ppm/ °C. © (2014) Trans Tech Publications, Switzerland.

关键词： Dielectric properties

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Preface photocatalytic materials for energy and environmental applications

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Applied Surface Science 2014年第1期319卷 1-1页

作者： Yu, Jiaguo Jaroniec, Mietek State Key Laboratory of Advanced Technology For Material Synthesis and Processing Wuhan University of Technology Luoshi Road 122# Wuhan430070 China Department of Chemistry and Biochemistry KentState University KentOH44242 United States

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