采用热重、在线质谱、X射线衍射和透射电镜等技术研究了热处理对多元醇法制备的PtRu/C电催化剂催化活性的影响.结果表明,热处理前电催化剂表面吸附较多残余物种,在惰性气氛中200℃下热处理2h可以去除部分吸附物种.虽然热处理后电催化剂的平均粒径比热处理前稍有增大,但电催化剂颗粒的分散度仍较高.热处理后电催化剂催化甲醇电氧化反应的活性明显提高.
The effect of heat treatment on catalytic activity of a PtRu/C electrocatalyst synthesized by the polyol method was investigated by thermogravimetry, on-line mass spectroscopy, X-ray diffraction, and transmission electron microscopy. The results indicate that abundant species adsorbs on the electrocatalyst surface, which can be effectively removed by heat-treating at 200 ℃ under inert atmosphere for 2 h. The particle size of the electrocatalyst increases slightly after heat treatment, but the particles remain good dispersion on the carbon support. Electrochemical and direct methanol fuel cell single cell test results indicate that the catalytic activity of PtRu/C for methanol electrooxidation is greatly improved by the heat treatment process.