Abstract: Tungsten carbide/carbon nanotubes composite (WC-CNTs) was prepared through surface decoration and in situ reduction and carbonization technology. Furthermore, its supported Pt electrocatalyst was prepared by the microwave-assisted polyol method. Compared to Pt/CNTs catalyst, Pt/WC-CNTs catalyst showed higher electrocatalytic activities for the oxygen reduction reaction (ORR), with lower overpotential, higher current density and higher exchange current density, lower charge transfer resistance and better selectivity towards ORR. XRD and TEM results indicated that Pt/WC-CNTs catalyst was mainly made of WC, Pt and CNTs. Fine Pt particles were dispersed on outside surfaces of WC-CNTs. Pt nanoparticles were in contact with WC nanopaticles, which was helpful to the synergistic effect between them. Thus, the enhancement in electrocatalytic properties of the novel Pt/WC-CNTs catalyst was attributed to this synergistic effect between Pt and WC. The rotating disk electrode measurements were performed to gain insight into ORR performance on Pt/WC-CNTs catalyst. This observation suggested that a four-electron reduction process took place on the catalyst surfaces. Tungsten carbide/carbon nanotube supported Pt electrocatalysts with low cost and unique activity for ORR have good prospect for development in the fuel cell cathode catalyst research applications.

Key words: fuel cells, electrochemistry, composites, oxygen reduction reaction, carbon nanotubes, tungsten carbide

摘要： 通过表面修饰和还原碳化技术制备了以WC为主相的碳化钨/碳纳米管材料（WC-CNTs），并进一步采用微波多元醇法载铂制备复合催化剂Pt/WC-CNTs。该催化剂相比于Pt/CNTs催化剂，具有更低的过电位、更大的电流密度和交换电流密度，且具有更小的电荷转移电阻和更好的氧还原选择性，显示了优异的氧还原电催化性能。XRD结果表明催化剂由多晶面的WC、Pt晶粒和CNTs组成，TEM和HRTEM显示细小的Pt颗粒均匀地分布在WC-CNTs表面。Pt颗粒和WC颗粒紧密接触，这有利于它们之间的催化协同效应，从而大大增强了Pt的氧还原催化活性。旋转圆盘电极研究结果表明Pt/WC-CNTs催化剂对氧还原反应为直接四电子过程。碳化钨/碳纳米管载铂催化剂性能优异、成本较低，在燃料电池阴极催化剂的研究应用中具有良好的发展前景。

关键词: 燃料电池, 电化学, 复合材料, 氧还原, 碳纳米管, 碳化钨