摘要
本文应用低温原位红外光谱技术,以CO和NO作为红外探针分子,通过研究硫化态MoO_3/(?)-Al_2O_3,上CO、NO、O_2、H_2气体单独或交替吸附的红外光谱,观察到其表面存在两种不同性质的(?)位,它们对上述气体分子表现出吸附性能的差异,并讨论了这两种钼位的可能存在形式。
The adsorption characterization and the surface structure of sulfiled MoO_3(15wt.%)/γ-Al_2O_3 catalyst were investigated by in situ low temperature infrared spectroscopy, us- mg CO and NO as IR probe molecules.
For NO and CO alternate adsorption, the IR spectra showed that when the sample was preadsorbed by NO(1790, 1690cm^(-1)), it could still adsorb CO(2120cm^(-1)); however, when the sample was preadsorbed by CO, it could not adsorb NO at all. Similar phenomena were observed for O_2 and CO alternate adsorption and for H_2 and NO alternate adsorption. For H_2 and CO alternate adsorption, the IR spectra showed that once the sample was preadsorbed by H_2, it could not adsorb CO.
According to the results mentioned above, it was suggested that there were two kinds of Mo(CUS) (denoted as Mo_A(CUS) and Mo_B(CUS)) existing on the surface, Mo_A(CUS) might adsorb all of CO, NO, O_2 or H_2, Mo_B(CUS) might adsorb CO or H_2 only. The fraction of the former in the two kinds of Mo(CUS) was very amall. The possible states of the two kinds of Mo(CUS) were discussed.
基金
国家自然科学基金
中国科学院中国科技大学结构分析开放研究实验室基金
