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金属氧化物及其复合物的制备与性能研究
Research on Preparation and Characterization of Metal Oxide and Its Composites
【作者】 彭振军;
【导师】 徐惠;
【作者基本信息】 兰州理工大学 , 应用化学, 2012, 硕士
【摘要】 NiO、SnO2在电池、催化剂和传感器等领域是被广泛应用的一类金属氧化物功能材料。本论文利用水热法制备了NiO、SnO2纳米粉体。研究了在不同反应条件下水热法制备NiO前驱体对经热处理得到的NiO电极材料的电化学性能的影响,根据测试结果,选择了CuO掺杂改性以期得到电化学性能更优异的复合氧化物。为扩展NiO、SnO2的应用,合成了NiO/PPY复合材料,测试了复合材料在电化学和光催化等方面的性能;制备并测试了SnO2/PANI复合材料的导电性和光催化吸附性能。研究内容包括以下几个方面:(1)由水热法制备前驱体,经400℃煅烧得到网孔状结构的NiO,通过XRD、SEM和恒流充放电分析测试样品的相结构、微观形貌和电容特性。探讨了镍源、表面活性剂、物料比、水热反应时间、水热反应温度及煅烧温度对NiO电极材料的电化学性能影响。结果表明,制备的NiO为网孔状结构,在20mA·cm-2下放电比电容为939F/g,显示出良好电容特性。(2)采用浸渍-水热沉淀法合成CuO掺杂Ni(OH)2前驱体,经煅烧得NiO-CuO复合氧化物。分析了复合前后粒子结构和形貌的变化,采用电化学工作站对NiO-CuO电极材料进行了循环伏安和恒流充放电等电化学性能测试。结果表明,CuO掺杂后复合材料呈孔隙分布均匀的菜花状结构,减少了粒子间的团聚,提高了材料的稳定性,增大了材料的比表面积,在5mA/cm2的电流密度下放电比电容为822F/g,180次循环后衰减率仅为4.5%,循环可逆性能好。(3)经水热法制备了NiO纳米颗粒,再通过原位化学氧化聚合得到NiO/PPy复合材料,研究了复合材料的电化学性能和对偶氮类有机染料甲基橙的光催化降解性能。结果表明,聚吡咯包覆在NiO粒子表面,提高了分散性,体现出良好的协同效应。当NiO含量为30%时,在电位窗口为0-0.5V下,单电极比电容达250F/g,相比PPy提高了72F/g。在光照条件下,对甲基橙溶液的降解率达87.5%。(4)采用水热合成法制备了球状二氧化锡,并将聚苯胺原位生长在二氧化锡表面获得兼具导电性和光催化与吸附性能的PANI/SnO2纳米复合材料。考察了反应物配比对复合材料导电性及其光催化与吸附性能的影响。结果表明,掺杂30%SnO2纳米粒子时,复合材料的电导率为3.57S/cm,相比于掺杂态聚苯胺提高了将近十倍,对萘酚绿B的吸附降解率达98%,且循环使用率较高(80%±6%)。
【Abstract】 NiO and SnO2as a functional material, has been widely applied in the scopes of battery, catalysts and magnetic device et al. In this paper, the preparation of NiO and SnO2with Hydrothermal synthesis, and we studies the NiO electrode materials that get from calcining body precursor by the different raction conditions in the water hot influence of the electrochemical performance. According to the test results, it expects to get a more excellent electrochemical properties of the composite oxide by doping modified the CuO. For extending the application of NiO and SnO2, we synthesized the NiO/PPy composite materials and tested the electrochemical and optical catalytic properties, and studied the photocatalytic and adsorption performance of SnO2/PANI conductive composite materials. The main research content by following respects:(1) Nets hole shape structure of NiO electrode was obtained by thermal decomposition of precursor at400℃. The samples of phase structure, micro-cosmic morphology and electrochemical properties were characterized by XRD, SEM and constant-current charge-discharge testing techniques. The precursor of NiO electrode materials was obtained by the method of thermal decomposition, the electrochemical performance impact was discussed by the reaction conditions of Nickel source, surfactants, molar ratio, supercritical water time and temperature, calcining temperature. The results show that the specific capacitance of the NiO obtained after calcination as a single electrode was up to939F·g-1to20mA·cm-2discharge.(2) Nickel hydroxide doped with Copper Oxide were synthesized by dipping at hydrothermal process. They were annealed in air to obtain composite oxide. The samples of phase structure, micro-cosmic morphology and electrochemical properties were characterized by constant-current charge-discharge testing techniques. The results indicated that the porosity distribution uniform cauliflower shape structure of the composite material by CuO doped that has reduced the reunion of particles, and improved the stability of the material, and increased the surface area of the material. The NiO-CuO obtained after calcination as a single electrode was up to822F·g-1 to5mA·cm-2discharge. Then the attenuation rate was only4.5%after180cycle.(3) NiO powder prepared by hydrothermal method was gone through situ polymerization and then the composite materials NiO/PPy was obtained. The feasibility of Azo kind of organic dye methyl orange using NiO/PPy was studied and the influence of some factors such as light. The analysis showed that pyrrole which coated the surface of NiO nanoparticles improve the dispersion. The composite improved the properties of materials and reflected a good synergy effect. When NiO content was thirty percent, its single electrode specific capacitance was up to250F/g at the potential Window of0-0.5V. Then NiO/PPy had a very good degradation effect, with the degradation rate of Methyl orange solution up to87.5%in the lighting conditions.(4) SnO2nanoparticles with similar globular were prepared by hydrothermal method. PANI/SnO2composite material was prepared by in-situ polymerization. The influences of reactants’ratio of conductivity and photocatalytic adsorption performance of resulting composites were investigated. The results showed that, doping SnO2nanoparticles for30%, composite materials of electrical conductivity with highest for3.57S/cm, compared with the doped polyaniline improved modal nearly10times and alpha-naphthol green B photocatalytic degradation and adsorption rate reaches98%, circular utilization rate higher (80%+6%).
【Key words】 NiO; NiO-CuO; NiO/PPy composite materials; SnO2/PANIcomposite materials; electrochemical performance; photocatalytic performa;