LAUSR

Abstract The effects of alkali promoters on catalytic behaviors for synthesizing CH 3 SH over Mo-based catalysts were investigated. The selectivity of CH 3 SH for Na, K, Cs and non-alkali promoted catalysts are following in the order of Cs-Mo/SBA–15> K-Mo/SBA–15> Na-Mo/SBA–15> Mo/SBA-15. The addition of alkali metals dramatically improved the CH 3 SH selectivity and CO conversion. The highest selectivity of CH 3 SH was 66% obtained by incorporating Cs into Mo/SBA-15 which was superior to those reported in the current literature. Based on N 2 adsorption-desorption, XRD, Raman, XPS and NO-TPD characterizations, active MoS 2 species on oxidized Mo O-S species, obtained from the sulfidation temperature as low as 553 K, was considered as active sites for synthesizing CH 3 SH. And it deemed that the different alkali metals (Na, K, Cs) could give rise to the difference in the sulfidation degree of Mo oxidized species and modify the chemical and electronic environment of the active sites, which resulted in the generation of distinguished concentration of Mo containing coordinatively unsaturated sites (Mo-CUS). Those concentrations of Mo-CUS were detected by NO-TPD to be 161, 210 and 222μmol/g, respectively, which had a positive relationship with the selectivity of CH 3 SH.