化工学报 ›› 2009, Vol. 60 ›› Issue (10): 2633-2639.

• 材料化学工程与纳米技术 • 上一篇    下一篇

Pt/WC催化剂的制备及其在气体扩散电极上的氧还原性能

马淳安;黄赟;朱英红;陈赵扬;林文锋   

  1. 浙江工业大学化学与工程材料学院,绿色化学合成技术国家重点实验室培育基地;英国女王大学化学化工学院
  • 出版日期:2009-10-05 发布日期:2009-10-05

Preparation and characterization of Pt/WC catalyst for oxygen reduction at gas-diffusion electrod

MA Chun’an; HUANG Yun; ZHU Yinghong; CHEN Zhaoyang;LIN Wenfeng   

  • Online:2009-10-05 Published:2009-10-05

摘要:

以喷雾干燥处理的偏钨酸铵为前驱体,采用CO/CO2为还原碳化气氛,利用程序升温气固反应法制备了分散性良好的空心球状WC粉体,并分别以WC和Vulcan XC-72R碳粉为载体,采用液相沉积还原法制备了Pt/WC及Pt/C催化剂。XRD和SEM测试结果表明, 所制备催化剂中Pt/WC的Pt粒子粒径要大于Pt/C。酸性条件下氧电极极化曲线测试结果表明, Pt/WC的氧还原催化性能要优于Pt/C,这主要表现在同一电位下较高的电流密度及还原起始电位正移约28 mV。讨论了Pt/WC催化性能提高的可能原因及催化机理,并对控制条件下Pt/WC氧气扩散电极的交流阻抗谱进行了研究。

关键词:

碳化钨, Pt/WC, 氧气扩散电极, 氧还原, 交流阻抗

Abstract:

By using spray-drying treated ammonium metatungstate (AMT) as precursor, the hollow globular tungsten carbide (WC) catalysts were prepared by sphere miniaturation-gas-solid reaction, and then the catalysts Pt/WC and Pt/C were prepared by reduction of platinum salts with HCHO in H2O solvent.The size of Pt metal particles in both catalysts was characterized by XRD and SEM, and the results indicated that Pt metal particles were 10.6 nm in Pt/WC while they were 2.8 nm in Pt/C. The measured polarisation curves of oxygen reduction reaction (ORR) in the gas diffusion electrode showed that Pt/WC oxygen-diffusion electrode exhibited a better electro-catalytic properties than Pt/C in acid solution, as shown by the higher current density at the same potential and initial potential of oxygen reduction positive.Then the possible reason and electro-catalytic mechanism were discussed, and the AC impedance spectra of gas diffusion electrode with Pt/WC under the controlled conditions were also studied.

Key words:

碳化钨, Pt/WC, 氧气扩散电极, 氧还原, 交流阻抗