摘要
假定单一物种的ＸＰＳ峰形为高斯形，对钼、硫和铑峰进行理论拟合，计算各价态物种表面原子浓度。它们的存在形式各为ＭｏＳ２、富硫环境的ＭｏＳ２＋ｘ、未完全硫化还原的Ｍｏ６＋和Ｍｏ５＋、Ｓ６＋、单质Ｓ０或Ｓｎ、Ｓ２－和富硫环境中的硫钼结构或（Ｓ－Ｓ）２－硫链和Ｒｈｎ＋（ｎ＝３，２，１，０）。分析发现，催化剂加铑使钼易被硫化还原，铑钼作用可以稳定Ｒｈｎ＋的存在。
The surface Mo,S and Rh species in the sulfided Mo-K-Rh/Al 2O 3 catalysts with variable Rh contents were investigated by XPS.From their analyses of the fitting results of the XPS spectra,it was found that the Mo species in the catalysts are MoS 2,MoS 2+x in the sulfur-enriched species and Mo 5+ and Mo 6+ .The S in the catalysts can take the forms of S 6+ ,S 0 or S n,S 2- and (S-S) 2- in the sulfur-enriched species.With the increase of the Rh content in the catalysts,the surface concentrations of MoS 2+x ,Mo 6+ ,S 2- 2 and S 6+ decrease,while those of Mo 4+ ,Mo 5+ ,S 2- and S 0 increase to some extent indicating that the addition of Rh in the catalysts promotes the sulfidation of molybdena.Because of the interaction with the Mo component,the Rh species could be existed not only as Rh 0,but also as Rh n+ (n=1,2 and 3) which is most probably responsible for the improved properties of the catalysts for alcohol synthesis from syngas.
基金
国家自然基金
