Highly active Ni sub(2)P/SiO sub(2) catalysts phosphorized by triphenylphosphine in liquid phase for the hydrotreating reactions

A highly loaded and dispersed 60%Ni/SiO sub(2) catalyst was phosphorized by triphenylphosphine (PPh sub(3)) in liquid phase for the preparation of highly loaded and dispersed Ni sub(2)P/SiO sub(2) catalysts. It was found that without pre-reduction, the Ni/SiO sub(2) was difficult to be phosphorized by PPh sub(3), and large Ni sub(2)P particles were resulted at the high phosphidation temperatures (543-593 K). When the Ni/SiO sub(2) was pre-reduced, the highly dispersed nano nickel particles formed were easily phosphorized by PPh sub(3) at the lower temperatures (443-543 K). The resulted Ni sub(2)P/SiO sub(2) catalyst phosphorized by PPh sub(3) at 443 K possessed small and homogeneous Ni sub(2)P particles ( similar to 6 nm) with the high Ni sub(2)P active site density (324 mu mol/g) as titrated by the adsorption of CO. It was significantly more active than the Ni sub(2)P/SiO sub(2) catalyst phosphorized by PH sub(3) in gas phase with the Ni sub(2)P active site density of 263 mu mol/g for the hydrodesulphurization of dibenzothiophene and hydrogenation of tetralin to decalin in a model diesel.