Effect of sulfidation temperature on the intrinsic activity of Co–MoS 2 and Co–WS 2 hydrodesulfurization catalysts

Abstract

The effect of presulfidation temperature on the magnetic property, local structure, and intrinsic hydrodesulfurization activity of Co–Mo(W)–S has been studied with SiO 2-supported Co–Mo and Co–W sulfide catalysts prepared by exposing presulfided MoS 2/SiO 2 and WS 2/SiO 2, respectively, to a vapor of Co(CO) 3NO. A TPS study shows that complete sulfidation of Mo(W) precursors to Mo(W)S 2 particles is required for the formation of Co–Mo(W)–S Type II. The intrinsic activity of Co–W–S Type II is 1.6 times as high as that of Co–Mo–S Type II. The Co K-edge EXAFS analysis of Co–Mo(W)–S confirms the formation of dinuclear Co sulfide clusters on Mo(W)S 2 edges. The intrinsic activity of Co–Mo–S is correlated with the Co–S–Co antiferromagnetic interaction strength, suggesting modifications of the electronic state and local structure of Co–Mo–S by MoS 2–O-support interactions, in conformity with the EXAFS analysis.