碱金属助剂对 Au-Pt/CeO2 催化剂催化水煤气变换反应活性的影响

 制备了碱金属 M (M = Na, K, Rb 和 Cs) 掺杂的 Au-Pt/CeO2 催化剂, 考察了其催化水煤气变换反应的活性, 并采用 X 射线衍射、H2 程序升温还原、紫外-可见漫反射光谱和 X 射线光电子能谱技术研究了 K 助剂对 Au-Pt/CeO2 催化剂结构和表面性质的影响. 结果表明, 添加少量电负性较低的 K 虽然使 Pt 的还原变得困难, 但有利于 Au 金属态的稳定, 并使催化剂表面 Ce3+ 富集而产生氧空位, 显著提高了 Au-Pt/CeO2 催化剂活性. 当 K 负载量为 0.025%, 反应温度 250 oC 时, CO 转化率可达 95%.

Effect of Alkali Metal Promoters on Water-Gas Shift Activity over Au-Pt/CeO2 Catalyst

Au-Pt/CeO2 catalyst samples modified with alkali metals M (M = Na, K, Rb, and Cs) were prepared and their catalytic activity for water-gas shift (WGS) was evaluated. The structure and surface properties of the Au-Pt/CeO2 catalyst promoted by potassium were investigated by X-ray powder diffraction, H2 temperature-programmed reduction, ultraviolet-visible diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy. The higher activity obtained on the K-promoted Au-Pt/CeO2 sample was possibly due to the reduction of Au3+ species and the enrichment of Ce3+ on the catalyst surface, which generated more oxygen vacancies. The catalytic activity of Au-Pt/CeO2 was greatly influenced by the alkali metals. When the K content was 0.025%, the CO conversion achieved up to 95% at 250 oC.