有机溶胶法制备Pt/C催化剂的影响因素

Factors to Affect Preparation of Pt/C Catalyst via Organic Colloidal Method

考察了有机溶胶法制备催化剂的过程中,碳载体的预处理、反应气氛、还原温度以及起始还原pH值等因素对制得的催化剂性能的影响.实验结果表明:在适当温度下对碳载体进行热处理可以显著改善活性组分的分散度和提高催化剂的性能,最佳的处理温度为300℃;在氮气气氛下制备的催化剂的性能明显优于在空气气氛下制备的催化剂;一般情况下,较低的还原温度有利于获得分散度较高的催化剂,最佳的还原温度为140℃左右,高于此温度制得的催化剂的性能有下降趋势;最佳的起始pH值为11左右.采用优化条件制备的Pt/C催化剂对甲醇氧化的电化学性能优于商品Pt/C催化剂.

This paper deals with the effects of some preparation factors, such as the pretreatment of carbon support, the preparation conditions, the reduction temperature and the initial pH value, on the properties of catalysts prepared via the organic colloidal method. Experimental results show that the heat pretreatment of carbon support at a suitable temperature, especially at the optimal value of 300 ℃ , greatly enhances the dispersion of active components and the performance of the catalyst, that the catalyst prepared in nitrogen atmosphere behaves better performances than that prepared in air atmosphere, that a low reduction temperature benefits the preparation of high-dispersion catalyst, that the catalyst prepared over the optimal reduction temperature （140 ℃ ） shows a slight activity decline, and that the optimal initial pH value is about 11. It is thus demonstrated that the Pt/C catalyst prepared at the optimal conditions possesses higher electrochemical activity for the oxidation of methanol, as compared with the commercial Pt/C catalyst.