防水型碳化钨气体扩散电极的研究

碳化钨(WC)以高硬度、高耐磨性的特性历来深受治金学家重视,常用它制造刀具、量具和模具,近二十余年才将其作为催化剂加以研究.这些年来,人们已发现WC催化剂具有较强的耐酸性、良好的导电性和电催化活性,且不受任何浓度的一氧化碳和几个PPM的硫化氢中毒,在加氢和脱氢方面,某些性质很类似于铂,故颇受人们关注. 本工作采用与常规不同的制备方法,制成高活性碳化钨粉末催化剂,曾先后对WC粉末在不同气氛中的热稳定性、几种溶液中的电化学稳定性及其阳极氧化机理进行了研究,并将WC粉末用作电催化剂制成半防水型氢电极,以碳为氯电极材料,单电池电极面积0.1m~2,由10个单电池按复极式串联成20D余瓦的氢-氯燃料电池组,在工厂中连续运行三个月,WC氢电极性能保持稳定。在此基础上,为进一步提高WC氢电极活性,提出了防水型WC气体扩散电极的研究.本文主要报导碳化钨粉末制备中物相组成、比表面及其电极制备条件对电极活性的影响,以及该电极的主要性能。

Research on the Waterproof Gas-Diffusion Electrode of Tungsten Carbide

A gas-diffusion electrode of WC was made by active WC powder, PTFE with some additives. The influences of the electro-catalytic activity of Tungsten Carbide (WC) powder and the preparation of the electrode on its activity have been investigated. The results show that the activity of the waterproof gas-diffusion electrode of WC is directly related to the composition, the specific surface area of WC powder, the loading capacity of WC powder and PTFE content in the electrode. At η=250 mV, the appa-rent activation energies (kJ·mol~(-1).) of hydrogen ionisation reaction (HIR) for the electrode are 23.3 in 3.5 mol·L~(-1) HCl, 14.5 in 2.0 mol·L~(-1) H_2SO_4 and 13.7 in 85% H_3PO_4 respectively. When the electrode is polarized to 250 mV (vs. DHE) in 2.0 mol·L~(-1) H_2SO_4 at 60 ℃, the current dentity of HIR is 3020 mA·g~(-1) and the electrode has the highest activity.