用XPS和TPR谱学表征方法,研究钾助剂对负载型Co-Mo-K-O/γ-Al2O3水煤气耐硫变换催化剂的作用.XPS表征显示,硫化态催化剂随着钾添加量的增加,低价态钼和S2-增加,(S-S)2-受抑制,(Mo4++Mo5+)/Mo6+质量比为0.8~1和较多的S2-物种有利于提高催化剂的低温活性.TPR表征结果示出,硫化态及工作态催化剂皆出现α、β2个吸氢峰,可分别归属Mo6+→Mo5+和Mo5+→Mon+(n=4,3,2)的还原过程;工作态催化剂α峰峰温较硫化态低,β峰为宽峰带低价钼混合峰;吸氢峰的大小与催化剂低温活性密切相关.
The XPS, TPR techniques were used to study the promotion effectof K2CO3 to the supported catalyst Co-Mo-K-O/γ-Al2O3 for water gas shift. The XPS results show that the amount of low valence molybdenum and S2- increases with increase of the content of K in sulfured catalyst, and (S-S)2- is suppressed. It is found that keeping the ratio (Mo4++Mo5+)/Mo6+ at 0.8~1 level and remaining more S2- species on the catalyst are in favor of the improvement of the catalytic activity at low temperature. Two hydrogen-adsorped peaks of TPR, namely α and β peaks, which can be ascribed to Mo6+→Mo5+ and Mo5+→Mon+(n=4,3,2) reduction processes respectively, appear both at sulfured state and functioning state. The experiment results indicate that there is a close relation between the altitude of the peaks and the activity of the catalyst at low temperature.
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