Hydrogenation Activity and Selectivity of Cobalt Boride and Cobalt Nickel Binary Boride Catalysts

Abstract Co–B catalyst has higher selectivity than Ni–B catalyst for the formation of α,β-unsaturated alcohols from α,β-unsaturated aldehydes and lower selectivity for the formation of olefins from acetylenes. The differences between the two catalysts can be ascribed to the differences in the adsorption strength of reactants on Co and Ni metals. The hydrogenation activities of the Co–Ni–B catalysts vary through a maximum, but the selectivities vary monotonously with nickel content. These features are explained in terms of the surface composition measured by XPS and of the surface area of the catalysts. The enrichment of nickel on the surface and the increase of the surface area are observed for the Co–Ni–B catalysts. Co–B catalysts modified by a small amount of metal salts (Fe, Cr, Cu, etc.) are more effective for the selective hydrogenation of α,β-unsaturated aldehydes than co-precipitated binary boride catalysts.