Modulation the metal-support interactions of potassium molybdenum-based catalysts for tuned catalytic performance of synthesizing CH3SH

Abstract

Modulation of the metal-support interactions (MSI) is an effective means to improve the performance of supported catalysts, but the role of the metal-support effect in the synthesis of CH3SH from CO/H2/H2S mixtures has not been recognized. Here, three different interactions, namely weak MSI, strong MSI and electronic MSI are constructed over K-promoted MoS2-base catalysts and investigated for the synthesis of CH3SH. The catalytic activity experiments show that the K-Mo catalyst with strong MSI has the highest formation rate toward CH3SH, while the K-Mo catalyst with electronic MSI instead shows the worst formation rate toward CH3SH. The characterizations suggest that the strong MSI facilitates the enhancement of Mo-S bond strength and the production of few layers, shorter slab and ordered K-MoS2 particles. The former benefits the formation and stabilization of C-S intermediate species and subsequent hydrogenation to CH3SH, while the latter promotes the generation of more Mo-coordinatively unsaturated sites (Mo-CUS) and thus facilitates the first-step adsorption and activation of reactants. In contrast, electronic MSI weakens the strength of the Mo-S bond, which inhibits the generation of C-S intermediate species. On the other hand, the presence of electronic MSI leads to the generation of Mo-Ov-Ti interfacial sites, which is favorable for the hydrogenolysis of CH3SH to CH4. This work provides an insight into the construction and selection of metal-support interactions for heterogeneous catalysis.