Effect of alumina support on the formation of the active phase of selective hydrodesulfurization catalysts Co-Mo/Al₂O₃

Two different commercial alumina supports were used for the preparation of selective hydrodesulfurization (HDS) catalysts Co-Mo/Al₂O ₃. The effect of support properties on the HDS activity and selectivity of the corresponding Co-Mo catalysts were studied by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, scanning transmission electron microscopy-energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The HDS activity and selectivity were measured using a continuous flow fixed-bed microreactor. The Al₂O₃ support with higher crystallinity and fewer hydroxyl groups had a moderate metal-support interaction, which resulted in an increase of the average slab length and stacking number of MoS₂. This gave more formation of the active CoMoS phase and an increase in HDS activity and selectivity.