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Preparation and Li^+ storage properties of hierarchical hollow porous carbon spheres

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Particuology 2014年第3期12卷 44-50页

作者： Xiaofeng Wu Wenxiang Tang Kejia Jiao yunfa chen State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of Sciences Graduate University of Chinese Academy of Sciences

Hollow ordered porous carbon spheres （HOPCS） with a hierarchical structure were prepared by templating with hollow ordered mesoporous silica spheres （HOMSS）. Scanning electron microscopy （SEM） and transmission electron microscopy （TEM） showed that HOPCS exhibited a spherical hollow morphology. High-resolution TEM, small angle X-ray diffraction （SAXRD） and N2 sorption measurements confirmed that HOPCS inversely replicated the unconnected hexagonal-stacked pore structure of HOMSS, and possessed ordered porosity. HOPCS exhibited a higher storage capacity for Li^＋ ion battery （LIB） of 527.6 mA h/g, and good cycling performance. A large capacity loss during the first discharge-charge cycle was found attributed to the high content of micropores. The cycling performance was derived from the hierarchical structure.

关键词： Hierarchical structure MCM-41 silica Nanostructured carbon Lithium storage

Extraction of scandium from red mud by modified activated carbon and kinetics study

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Rare Metals 2008年第3期27卷 223-227页

作者： ZHOU Hualei LI Dongyan TIAN Yajun chen yunfa State Key Laboratory of Multi-phase Complex System lnstituteqfProcess Engineering Chinese Academy of Sciences Beijing 100080 China School of Applied Sciences University of Science and Technology Beo＇ing Beijing 100083 China

Activated carbon （AC） was modified by tri-butyl phosphate （TBP） for selectively extracting scandium from red mud and characterized by BET （Brunauer-Emmett-Teller） surface area. The modified AC had a preferential adsorption to scandium. The influences of adsorbent dos- age, adsorption temperature, and time on adsorption capacity and selectivity to scandium were examined. An optimum adsorbent dosage （-6.25 g/L）, adsorption temperature （308 K）, and adsorption time （40 min） were figured out. A pseudo-second-order kinetics model was employed for describing the adsorption process of scandium.

关键词： modified activated carbon adsorption red mud scandium

Mechanism of dichloromethane disproportionation over mesoporous TiO2 under low temperature

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Frontiers of Environmental Science & Engineering 2019年第2期13卷 73-84页

作者： Yuzhou Deng Shengpan Peng Haidi Liu Shuangde Li yunfa chen State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Center for Excellence in Regional Atmospheric Environment Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China

Mesoporous TiO2 was synthesized via nonhydrolytic template-mediated sol-gel *** degradation performance upon dichloromethane over as-prepared mesoporous TiO2,pure anatase and rutile were investigated *** took place over as-made mesoporous TiO2 and pure anatase under the presence of *** mechanism of disproportionation was studied by in situ *** interaction between chloromethoxy species and bridge coordinated methylenes was the key step of *** species and methoxy groups would be formed and further turned into carbon monoxide and methyl ***(001)played an important role for disproportionation in that water could be dissociated into surface hydroxyl groups on such *** a result,the consumed hydroxyl groups would be *** addition,there was another competitive oxidation route governed by free hydroxyl *** this route,chloromethoxy groups would be oxidized into formate species by hydroxyl radicals transfering from the surface of *** latter route would be more favorable at higher temperature.

关键词： Dichloromethane Disproportionation Mechanism Anatase(001) Water dissociation

Preparation and electrochemical performance of carbon-coated LiFePO4/LiMnPO4-positive material for a Li-ion battery

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Particuology 2017年第1期15卷 144-150页

作者： Qiangqiang Tan Bo Yan Yuxing Xu yunfa chen Jun Yang State Key Laboratory of Multiphase Complex Systems Institute of Process Engineering Chinese Academy of Sciences Beijing 100190 China University of Chinese Academy of Sciences Beijing 100049 China

Lithium iron phosphate （LiFePO4）/lithium manganese phosphate （LiMnPO4）-positive material was suc- cessfully prepared through ball milling and high-temperature sintering using manganese acetate, lithium hydroxide, ammonium dihydrogen phosphate, and ferrous oxalate as raw materials. The as-prepared samples were characterized by X-ray diffraction, transmission electron microscopy, scanning elec- tron microscopy, a constant current charge-discharge test, cyclic voltammetry, and electrochemical impedance spectroscopy. The effects of lithium iron phosphate coating were also discussed. Because of its special core-shell structure, the as-prepared ***0.3PO4-LiFeP04-C exhibits excellent electro- chemical performance. The discharge capacity reached 136.6 mAh/g and the specific discharge energy reached 506.9 Wh/kg at a rate of 0.1 C.

关键词： LiMn1-xFexPO4 Composite Core-shell structure Positive material Li-ion battery

Large-scale synthesis of hierarchical MnO_2 for benzene catalytic oxidation

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Particuology 2014年第3期12卷 71-75页

作者： Dongyan Li Genli Shen Wenxiang Tang Haidi Liu yunfa chen State Key Laboratory of Multi-phase Complex System Institute of Process EngineeringChinese Academy of Sciences University of Chinese Academy of Sciences

Hierarchical sea-urchin-shaped manganese oxide microspheres were synthesized via a facile method based on the reaction between KMnO4 and MnSO4 in HNO3 solution at 50℃. The average diameter of the microspheres is -850 nm. The microspheres consist of a core of diameter of -800 nm and nanorods of width -50 nm. The nanorods exist at the edge of the core, The Brunauer-Emmett-Teller surface area of the sea-urchin-shaped microspheres is 259.4 m^2/g. A possible formation mechanism of the hierarchical sea-urchin-shaped microspheres is proposed. The temperature for 90% conversion of benzene （T90%） on the hierarchical urchin-shaped MnO2 microspheres is about 218 ℃.

关键词： Manganese oxide Hierarchical Catalyst Benzene

In-situ electro-deposition synthesis of MnO_(x)-NiCo_(2)O_(4) monolithic catalyst with rich phase interfaces

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Chinese Chemical Letters 2021年第1期32卷 21-24页

作者： Dongdong Wang Yingchao Du Xiaoze Wang Zhaxi Cuo yunfa chen State Key Laboratory of Multi-Phase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Resource Chemistry and Ecoenviromental Protection in Tibetan Plateau (Qinghai Nationalities University)State Ethnic Affairs CommissionSchool of Chemistry and Chemical EngineeringXining 810007China CAS Center for Excellence in Urban Atmospheric Environment Xiamen 361021China

A hierarchically structured MnO_(x)-NiCo_(2)O_(4) monolithic catalyst with rich phase interfaces was designed by a simple,eco-friendly and time-saving in-situ electro-deposition *** abundance of active oxygen species due to this rich phase interfaces contributed to the excellent benzene combustion performance of MnO_(x)-NiCo_(2)O_(4)-2:2 sample,oxidizing about 90% of benzene(T_(90)) at 198℃ under 12000 h^(-1) gaseous hourly space *** work shed new light on the design of excellent monolithic catalysts,which might pave the way for the industrialization of benzene combustion.

关键词： Rich phase interfaces In-situ electro-deposition Active oxygen species Benzene combustion MnO_(x)-NiCo_(2)O_(4)

Filter paper-templated preparation of ZnO thin films and examination of their gas-sensing properties

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Particuology 2011年第3期9卷 253-259页

作者： Bao Wang Ning Han Dong Meng Renliang Yue Jinghui Yan yunfa chen School of Chemistry and Environmental Engineering Changchun University of Science and Technology Changchun 130022 China Institute of Process Engineering Chinese Academy of Sciences Beijing 100190 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

ZnO thin films prepared by using quantitative filter paper as a template and Zn（CH3CO2）2.2H2O ethanol precursor solution were characterized by scanning electron microscopy （SEM） and X-ray diffraction （XRD）. The effects of sample calcination temperature, precursor concentration and filter paper types were studied, and the growth process was investigated by infra-red （IR） spectroscopy and thermogravimettic analysis/differential thermal analysis （TGA/DTA）. The results show that samples soaked in a 1.5 mol/L Zn（CH3 CO2）2.2H2O ethanol solution and calcined at 600 ℃ yield ZnO films of uniform particle size, approximately 30, 40 and 50 nm. for fast-, medium- and slow-speed filter papers, respectively. The formaldehyde gas sensing properties of the ZnO nanoparticles were tested, showing that the material prepared from fast-speed filter paper has a higher response to 120-205 ppm formaldehyde at 400 ℃ than that prepared from medium- or slow-sneed paper, which depends on the narticle size.

关键词： ZnO thin films Quantitative filter paper Template Gas sensing properties

Effect of process conditions on the synthesis of carbon nanotubes by catalytic decomposition of methane

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China Particuology 2007年第3期5卷 213-219页

作者： Shuanglin Zhan Yajun Tian Yanbin Cui Hao Wu Yonggang Wang Shufeng Ye yunfa chen Institute of Process Engineering Chinese Academy of Sciences Beijing 100080 China Graduate University of Chinese Academy of Sciences Beijing 100049 China China University of Mining and Technology Beijing 100083 China

A new dual-composition catalyst based on Ni-Mo/MgO with high efficiency of producing carbon nanotubes （CNTs） from methane was reported recently. In the present article, with this type of catalyst, the impact of such experimental parameters as reaction temperature, reaction time, concentration of H2, flow rate ratio of CH4 to H2 on yield and graphitization were investigated, leading to the following optimal growth conditions： reaction time 60min, reaction temperature 900℃, CH4：H2 about 100：20mL/min, under which high-yield multi-walled CNTs bundles were synthesized. Raman measurement indicated that the as-synthesized product was well-graphitized, and the purity was estimated over 95% by TG-DSC analysis. In terms of the above results, an explanation of high-efficiency formation of CNTs bundles and the co-catalysis mechanism of Ni-Mo/MgO were suggested. 2007 Chinese Societv of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V.

关键词： Carbon nanotubes Catalytic decomposition Carbon yield Graphitization degree

Heterojunctioned CuO/Cu_(2)O catalyst for highly efficient ozone removal

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Journal of Environmental Sciences 2023年第3期125卷 340-348页

作者： Guojun Ma Wenxiang Tang AnqiWang Le Zhang Jian Guan Ning Han yunfa chen Key Laboratory of Science and Technology on Particle Materials Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China Center for Excellence in Regional Atmospheric Environment Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China School of Chemical Engineering Sichuan UniversityChengdu 610065China

In recent years, near surface ozone pollution, has attracted more and more attention,which necessitates the development of high efficient and low cost catalysts. In this work,Cu O/Cu_(2)O heterojunctioned catalyst is fabricated by heating Cu_(2)O at high temperature, and is adopted as ozone decomposition catalyst. The results show that after Cu_(2)O is heated at180℃conversion of ozone increases from 75.2% to 89.3% at mass space velocity 1,920,000cm^(3)/(g·hr) in dry air with 1000 ppm V ozone, which indicates that this heterojunction catalyst is one of the most efficient catalysts reported at present. Catalysts are characterized by electron paramagnetic resonance spectroscopy and ultraviolet photoelectron spectroscopy,which confirmed that the heterojunction promotes the electron transfer in the catalytic process and creates more defects and oxygen vacancies in the Cu O/Cu_(2)O interfaces. This procedure of manufacturing heterostructures would also be applicable to other metal oxide catalysts, and it is expected to be more widely applied to the synthesis of high-efficiency heterostructured catalysts in the future.

关键词： Cu_(2)O Ozone decomposition CuO Heterojunction