Direct methanation with supported MoS2 nano-flakes: Relationship between structure and activity

Abstract With a rapid developing global economy and population growth, demand for natural gas is expected to outpace supply. Current state of the art methanation catalysts like nickel-based (Ni) catalysts are susceptible to poisoning by sulfuric compounds present in the syngas. MoS 2 is one of the few methanation catalysts not affected by sulfuric impurities, allowing the use of syngas feedstocks from coal gasification for direct methanation before extensive clean-up of the syngas. Increasing the number of Mo active sites is challenging since they are mostly located at the edges while the basal planes are mostly inert. In this study, we report a method of producing MoS 2 with a significant amount of exposed edges (nano-flakes) which resulted in highly active MoS 2 catalysts. Effects of support, Mo precursors and synthesis techniques on the formation of nano-MoS 2 structure and methanation activity have been investigated. MoS 2 nano-flakes can be produced from a solvothermal method or thermolysis of a thiomolydate precursor. The resulting MoS 2 catalysts were tested for direct methanation of CO with H 2 to CO ratio of 1:1 and 3000 ppm of H 2 S under 3 MPa. X-ray absorption spectroscopy was also utilized to gain more insight into the structure of the catalysts.