The combined DFT and microkinetics methods to investigate the favorite sulfur vacancies of Co(Ni)MoS2 catalysts for maximizing HDS/HYDO selectivity

The adsorptions and reactions of thiophene and 1-hexene on different sulfur vacancies over Mo edges, S edges, and corners of Co(Ni)-MoS2 catalysts were systematically researched based on density functional theory (DFT) and microkinetic study. The adsorption of H2S and C2H4 were proposed as the descriptors of adsorption of sterically unhindered thiophene and 1-hexene. Thiophene shows lager adsorption strength than 1-hexene on the sulfur vacancies of S edges with Co-doping. In addition, there is lower reaction barrier of hydrodesulfurization (HDS) than hydrogenation of olefin (HYDO) on the sulfur vacancy over S edge with Co-doping and desulf-urization (DDS) route is more popular on S edges. Furthermore, considering the whole HDS and HYDO cycle process under different reaction conditions by microkinetic analysis, the sulfur vacancy over S edge with Co-doping is proposed as required with outstanding HDS/HYDO selectivity (close to 100 %) and HDS catalysis performance.