Understanding the relationship between composition and hydrodesulfurization properties for cobalt phosphide catalysts Original Research Article

Silica-supported cobalt phosphide (CoxPy/SiO2) catalysts, prepared from precursors having P/Co molar ratios in the range 0.50–2.0, were characterized and evaluated for thiophene hydrodesulfurization (HDS). The HDS activities of the CoxPy/SiO2 catalysts varied nearly four-fold depending on the composition of the Co phosphide phase, with the most active CoxPy/SiO2 catalyst corresponding to the precursor composition having just enough P to ensure formation of phase-pure CoP on the silica support. The maximum in HDS activity observed for this Co phosphide composition can be correlated with a balance between site density (as measured by O2 chemisorption) and resistance to S incorporation (as measured by S analysis of catalysts subjected to an H2S/H2 treatment).