pH值对微波协助乙二醇法制备PtRu/C催化剂的影响

以微波协助乙二醇工艺合成了碳负载不同粒径大小的PtRu/C纳米催化剂, 主要考察了溶液pH值对PtRu粒子大小的影响. 利用紫外可见光谱、能量散射X射线谱、透射电镜和X射线衍射谱对PtRu纳米催化剂进行了表征. 结果表明, pH值是一个对PtRu粒子大小有着重要影响的因素. TEM结果显示随着溶液pH值的增加, PtRu粒径从3.5 nm减小到1.5 nm. 当溶液pH值达到11.0时, 由于金属粒子被保护, 合成的催化剂中金属载量明显减少. 溶液pH 值在9.0 右合成的PtRu/C催化剂具有适宜粒径(2.4 nm)和均匀分布的金属颗粒, 具有最好的甲醇电氧化活性.

Effects of pH on the PtRu/C Catalyst Prepared by Microwave-assisted Ethylene Glycol Process

PtRu nanoparticles supported on the carbon, with different mean particle sizes, were synthesized by microwave-assisted ethylene glycol process, the effects of pH on the PtRu/C catalyst were mainly investigated. UV-Vis spectroscopy, energy dispersive X-ray analysis, transmission electron microscopy, and X-ray diffraction were applied to characterize the PtRu nanoparticles. The solution pH had important influence on the metal particle size. TEMresults indicated that the PtRu mean particle size decreased from 3.5 nm to 1.5 nm with the increase of pH value. However, when pH value reached 11.0, the metal loading of synthesized catalyst decreased distinctly because the metal nanoparticles were protected in solution. The results showed that the PtRu/C catalyst synthesized at pH ca 9.0, with appropriate particle sizes (2.4 nm) and homogenous dispersed particles, had the highest electrocatalytic activity for methanol electrooxidation among all the synthesized catalysts.