Performance of dibenzothiophene hydrodesulfurization for WP/MCM-41 catalyst containing promoter nickel

 The supported tungsten phosphide catalysts with different content of nickle were prepared over MCM-41. The samples were characterized by X-ray diffraction(XRD), BET specific surface area, scanning electron microscopy(SEM) and X-ray photoelectron spectroscopy(XPS) methods. The dibenzothiophene(DBT) hydrodesulfurization(HDS) performance of catalysts was evaluated in a fixde-bed reactor at 633K, 3MPa H₂ and with a space velocity of 4h^-1.The results showed that the addition of Ni promoted the growth of active species WP and increased WP crystal dimension. Some content of nickel was favor to increase the BET specific surface area of catalyst. Ni had positive effects on the DBT HDS reaction of WP/MCM-41 catalysts. WP was the main active phase. The addition of small amount(1%) of nickle was favor to the formation of WP active phase and increased the active site number. The addition of excess content(5%, 9%) of nickel probably conduced the formation of a new active species with similar structure of Ni-W-P, which decreased the proportion of WP active phase on the catalyst surface and resulted in the decline of catalytic activity. Particularly, the catalyst with nickel content of 1% had high HDS activity, giving the DBT desulfurization rate and DBT conversion rate of 76.78% and 72.16%, respectively, which were 30.04% and 21.62% higher than those given by the catalyst without nickel addition. The hydrodesulfurization(HYD) was the dominant path for WP/MCM-41 catalysts in DBT HDS reaction. The HYD selectivity was improved with the increasing of nickel content of catalyst.