Effect of ZrO2 in Ni2P/ZrO2–Al2O3 catalysts on hydrotreating reactions

Catalysts 60% Ni/Al2O3 and 60% Ni/4% ZrO2–Al2O3 were prepared, and it was found that the addition of ZrO2 promoted reduction while maintaining the high dispersion of supported nickel. Upon phosphidation by triphenylphosphine (PPh3) in the liquid phase, the two catalysts were converted into corresponding Ni2P/Al2O3 and Ni2P/ZrO2–Al2O3 catalysts with highly dispersed Ni2P particles (6.3 and 6.8 nm, respectively), high CO uptakes (305 and 328 μmol g−1, respectively) and thus high activities for the hydrodesulfurization (HDS) of dibenzothiophene (DBT) and hydrogenation of tetralin to decalin. In particular, the Ni2P/ZrO2–Al2O3 was found to be significantly more active than the Ni2P/Al2O3 for the HDS of DBT and hydrogenation of tetralin to decalin. Although the presence of ZrO2 did not affect the heat of adsorption of CO on Ni2P, it significantly increased the heat and uptake of adsorption of H2 on Ni2P, which might account for the increased activity of Ni2P promoted by ZrO2.