Preparation of Tungsten Carbide and Titania Nanocomposite and Its Electrocatalytic Activity for Methanol

HU Xian-Chao, 浙江工业大学化学工程与材料学院, 杭州 310032;,School of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310032, P. R. China;, CHEN Dan, SHI Bin-Bin, LI Guo-Hua, 浙江工业大学分析测试中心, 杭州 310032;,Research Center of Analysis and Measurement, Zhejiang University of Technology, Hangzhou 310032, P. R. China;, 浙江工业大学绿色化学合成技术国家重点实验室培育基地, 杭州310032; 4浙江工业大学纳米科学与技术研究中心, 杭州 310032,State KeyLaboratory Breeding Base of Green Chemistry Synthesis Technology, Zhejiang University of Technology, Hangzhou 310032, P. R.China;
2011 Wuli huaxue xuebao  
1 浙江工业大学化学工程与材料学院, 杭州 310032; 2 浙江工业大学分析测试中心, 杭州 310032; 3 浙江工业大学绿色化学合 成技术国家重点实验室培育基地, 杭州 310032; 4 浙江工业大学纳米科学与技术研究中心, 杭州 310032) 摘要: 以市售纳米二氧化钛(TiO2)为载体, 六氯化钨为钨源, 将浸渍法与原位还原碳化技术相结合制备了核壳 结构碳化钨(WC)/TiO2纳米复合材料; 应用 X 射线衍射分析、 透射电子显微镜、 高分辨扫描透射成像和 X 射线能 量散射谱等手段对样品晶相、 形貌、 微结构和化学组成等特征进行了表征. 结果表明, 样品的晶相由金红石型 TiO2、 Ti4O7、 WC、 W2C 和 WxC 构成, 钨碳化物负载于钛氧化物外表面, 构成比较典型的核壳结构. 采用三电极体 系和循环伏安法测试了样品在碱性溶液中对甲醇的电催化氧化活性, 结果表明, 相比于纯碳化钨和二氧化钛, 复合材料的电催化活性得到了明显的提升. 样品电催化活性的提升与前驱体钨钛摩尔比、 还原碳化时间、 核壳
more » ... 组成以及核壳结构中二氧化钛和碳化钨之间的协同效应有关. 这说明金红石是能够 提升碳化钨电催化氧化活性的载体材料之一. Abstract: Tungsten carbide and titania nanocomposite with a core-shell structure was fabricated by combing chemical immersion with carbonization-reduction, using titania nanopowder as a support and tungsten hexachloride as a tungsten precursor. The crystal phase, morphology, microstructure, and chemical composition of the sample were characterized by X-ray diffraction, transmission electron microscopy, high resolution scanning transmission imaging, and energy dispersive spectroscopy (EDS). The results show that the crystal phase of the sample is composed of rutile, Ti4O7, WC, W2C, and WxC. The tungsten carbide particles coat onto the surface of the rutile support and thus form a core-shell structure. The electrocatalytic activity of the sample for methanol was measured by cyclic voltammetry with a three-electrode system in an alkaline solution. The results indicate that the electrocatalytic activity of the sample is higher than that of a pure titania phase and WC. The improvement in electrocatalytic activity is related to the reduction-carbonization time, the W to Ti molar ratio, the completeness of the shell layer in the core-shell structure, and the crystal phase of the sample. These factors can be correlated to a synergistic effect between titania and tungsten carbide in the nanocomposite. These imply that titania is a suitable support for the enhancement of the electrocatalytic activity of tungsten carbide.
doi:10.3866/pku.whxb20112863 fatcat:6n57q3nimffehpxofz5jjceslm