One member of a new family of catalysts for the removal of sulfur from petroleum feedstocks, nickel phosphide on silica (Ni2P/SiO2), is reported. The catalyst is able to effectively treat feeds containing alkylated heteroaromatics, the most tenacious of the sulfur compounds. Tests were conducted with model reagents as well as with real feedstocks, and comparisons were made with optimized commercial sulfide catalysts under realistic conditions of temperature and pressure. The phosphide catalyst showed superior activity, selectivity, and stability over the commercial catalysts. Characterization of the phosphide material by X-ray absorption spectroscopy showed that high activity was associated with Ni-P bonding in the Catalyst.