Acta Phys. -Chim. Sin. ›› 2012, Vol. 28 ›› Issue (09): 2077-2083.doi: 10.3866/PKU.WHXB201206042

• ELECTROCHEMISTRY AND NEW ENERGY • Previous Articles     Next Articles

Preparation and Electrocatalytic Activity of WC/W2C Nanocomposite with Core-Shell Structure

LI Guo-Hua1,2, CHEN Dan1, ZHENG Xiang1, XIE Wei-Miao1, CHENG Yuan1   

  1. 1. School of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310032, P. R. China;
    2. State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, Zhejiang University of Technology, Hangzhou 310032, P. R. China
  • Received:2012-03-16 Revised:2012-06-04 Published:2012-08-02
  • Contact: LI Guo-Hua E-mail:nanozjut@zjut.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (21173193).

Abstract:

A monotungsten carbide (WC)/bitungsten carbide (W2C) nanocomposite having a core-shell structure was prepared through a combination of surface coating and in situ reduction-carbonization, using ammonia meta-tungsten as tungsten source and iron oxide hydroxide as a hard support. The crystal phase, morphology, microstructure, and chemical components of the samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray energy dispersion spectroscopy (EDS). The results show that after calcination, the morphology, the crystal phases of the support, and the coating layer around the support are changed. After acid dissolution, reduction, and carbonization, the crystal phase of the final product is composed of WC and W2C; the microstructure of the sample particle is a core-shell structure in which WC forms the core and W2C forms the shell. Based on the characterization results, the formation mechanism of the core-shell structure is discussed. The electrocatalytic activities of the samples for methanol electrooxidation were investigated by cyclic voltammetry with a three-electrode system in acidic, neutral, alkaline aqueous solutions. The results show that the electrocatalytic activity of the sample for methanol oxidation is higher than that of tungsten carbide particles and hollow microsphere tungsten carbide. These indicate that the electrocatalytic activity of tungsten carbide can be improved through the formation of core-shell structure, and it is one of the efficient ways to improve the electrocatalytic activity of tungsten carbide.

Key words: Monotungsten carbide, Bitungsten carbide, Nanocomposite, Core-shell structure, Electrocatalytic activity

MSC2000: 

  • O646