物理化学学报 >> 2010, Vol. 26 >> Issue (05): 1317-1322.doi: 10.3866/PKU.WHXB20100337

催化和表面结构 上一篇    下一篇

WC/天然沸石纳米复合材料的制备与电催化活性

姚国新, 施斌斌, 李国华, 郑遗凡   

  1. 浙江工业大学化学工程与材料学院, 杭州 310032; 绿色化学合成技术国家重点实验室培育基地, 杭州 310032; 浙江工业大学纳米科学与工程技术研究中心, 杭州 310032; 浙江工业大学分析测试中心, 杭州 310032
  • 收稿日期:2009-09-08 修回日期:2009-12-03 发布日期:2010-04-29
  • 通讯作者: 李国华 E-mail:nanozjut@zjut.edu.cn

Preparation and Electrocatalytic Activity of Tungsten Carbide and Zeolite Nanocomposite

YAO Guo-Xin, SHI Bin-Bin, LI Guo-Hua, ZHENG Yi-Fan   

  1. School of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310032, P. R. China; State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, Hangzhou 310032, P. R. China; Research Center of Nanoscience and Technology, Zhejiang University of Technology, Hangzhou 310032, P. R. China; Research Center of Analysis and Measurement, Zhejiang University of Technology, Hangzhou 310032, P. R. China
  • Received:2009-09-08 Revised:2009-12-03 Published:2010-04-29
  • Contact: LI Guo-Hua E-mail:nanozjut@zjut.edu.cn

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摘要：

以天然沸石为载体, 偏钨酸铵为钨源, 将机械化学法与原位还原碳化技术结合, 制备了碳化钨与天然沸石的纳米复合材料. 制备过程中, 首先对天然沸石进行预处理, 然后按硅钨摩尔比为2:1配置偏钨酸铵与沸石混合物, 经机械球磨得到三氧化钨与沸石复合前驱体, 再将前驱体在管式炉内1173 K温度下, 在CH4与H2混合气氛中还原碳化即得碳化钨与沸石的纳米复合材料. 采用X射线衍射(XRD)、扫描电子显微镜(SEM)和X射线能量散射谱(EDS)分别对样品的晶相、形貌、微结构和化学组成进行了表征. 结果表明, 样品主要由一碳化钨、碳化二钨、石英、丝光沸石、斜发沸石等物相组成. 其中, 一碳化钨晶粒约为30 nm, 碳化二钨的晶粒约为20 nm. 应用粉末微电极测试了样品在中性溶液中对对硝基苯酚的电催化活性. 结果表明, 在中性溶液中样品对对硝基苯酚电催化活性优于介孔空心球状碳化钨, 样品的电还原催化活性与其WC的质量分数和WC与W2C的质量比相关. 碳化钨与沸石构成复合材料后, 两者具有明显的协同效应.

关键词: 碳化钨, 天然沸石, 纳米复合材料, 电催化活性, 协同效应

Abstract:

WC zeolite nanocomposite was synthesized by combining a mechano-chemical approach with the reduction-carbonization technique. We used natural zeolite as a support and ammonia metatungsten as a tungsten source. The pretreated zeolite was mixed with ammonia metatungsten at a n(Si):n(W)=2:1 by a ball miller to produce the WO3/zeolite precursor. The precursor was then reduced and carbonized in a CH4/H2 atmosphere at 1173 K in a furnace for a specific period of time. The product was characterized by X-ray diffraction (XRD), scanning electron microscopy(SEM), and X-ray energy diffusive spectroscopy (EDS). Results showed that the sample was composed of monotungsten carbide, bitungsten carbide, quartz, mordenite, and clinoptilolite. The diameter of the monotungsten carbide particles was found to be about 30 nm and that of bitungsten carbide about 20 nm. The electrocatalytic activity of the sample for p-nitrophenol in a neutral solution was measured using a powder microelectrode. Results show that the sample is electrocatalytically active in a neutral p-nitrophenol solution. The electrocatalytic activity of these samples is better than that of mesoporous tungsten carbide and this is due to the mass fraction of WC and the ratio of w(WC)/w(W2C). These results indicate that a synergistic effect exists between the tungsten carbide and the zeolite.

Key words: Tungsten carbide, Natural zeolite, Nanocomposite, Electrocatalytic activity, Synergistic effect