Influence of rare earth metals on structure and performance of Ni 2 P/MCM-41 hydrodesulfurisation catalysts

A series of rare-earth-modified M-Ni₂P/MCM-41 (M=Pr, Nd, Ce, La, Y) catalysts has been prepared by means of a temperature-programmed reduction method. The prepared catalysts were characterised by X-ray diffraction, N₂-adsorption specific surface area measurements, X-ray photoelectron spectroscopy and CO uptake. The effects of rare earth metals on catalyst activity for hydrodesulfurisation (HDS) of dibenzothiophene (DBT) were studied. The results showed that the addition of rare earth metals increases the surface area and pore volume of the catalysts. Rare earth metals can promote formation of the Ni₂P phase and induce a better Ni₂P dispersion but they do not change the mechanism of HDS of DBT. Pr-Ni₂P/MCM-41 exhibited the highest HDS activity. At reaction temperature of 300 °C, pressure of 3.0 MPa, hydrogen/oil volume ratio of 500, and weight hourly space velocity(WHSV) of 6.0 h⁻¹, the addition of Pr increased the conversion of HDS of DBT by 16.7%.