An exploration into potassium (K) containing MoS2 active phases and its transformation process over MoS2 based materials for producing methanethiol

Abstract MoS 2 -based catalysts showed great promise for converting CO/H 2 /H 2 S gas mixture into methanethiol (CH 3 SH). However, the active phases for this reaction were unexplored widely. In the present study, we tackle this issue through investigating the effect of potassium (K) and supports on the nature of MoS 2 catalysts via the characterizations of XRD, UV–vis, TPS, XPS, HR-TEM, as well as HAADF-STEM combined with energy-dispersive spectroscopy (EDS) etc. The results suggested that K species can not only lead to formation of different oxidized precursors but also affect the microstructure, surface morphology and electronic properties of active MoS 2 phases. Three sulfided species, i.e., pure MoS 2 , K-decorated MoS 2 and K-intercalated MoS 2 nanoslabs, were simultaneously detected, and were demonstrated to be derived from the reduction and sulfidation of oxidized precursors via O S exchange mechanism. Furthermore, the activity results showed that pure MoS 2 species worked only for the reaction of CO with H 2 S to COS, while K-decorated MoS 2 and K-intercalated MoS 2 nanoslabs exhibited unique ability for the hydrogenation of COS to produce CH 3 SH. K-decorated MoS 2 nanoslabs formed mainly on mesoporous SBA-15 support, which possessed higher CH 3 SH selectivity than that over K-intercalated MoS 2 generated primarily on SiO 2 support. In addition, the further improvement of CH 3 SH selectivity depended on the properties of support with respect to the dispersion, the high dispersion facilitated the formation of the increased amount of Mo-coordinatively unsaturated sites (CUS).