Surface structure and sulfidation behavior of Co-Mo and Co-W sulfide catalysts for the hydrodesulfurization of dibenzothiophene

Abstract The catalytic property and local structure of Co-MoS 2 and Co-WS 2 catalysts were investigated by means of the Co-CVD technique using Co(CO) 3 NO and XAFS. Comparing the catalytic activity for the HDS of DBT between Co-MoS 2 and Co-WS 2 catalysts before and after the CVD treatment, it was shown that the Co coverage of the edge sites of WS 2 particles is lower than that of MoS 2 particles, leading to a smaller amount of the Co-W-S structure in the catalyst. Furthermore, edge sites of WS 2 particles are more extensively blocked by excess Co sulfide particles than those of MoS 2 particles at a high Co loading (>5 wt%). In situ, W L 3 -edge, Mo K-edge and Co K-edge XAFS analyses during catalyst sulfidation revealed that sulfidation temperature of W atoms is much higher than those of Mo and Co. The difficulty in the formation of Co-W-S on the Co-WS 2 catalysts is related to this specific sulfidation behavior of W.