Comparative Investigation of (10%Co+0.5%Pd)/TiO2(Al2O3) Catalysts in CO Hydrogenation at Low and High Pressure

Abstract

Surface properties of prereduced (Co+Pd)/Al2O3 and (Co+Pd)/TiO2 catalysts were studied. Metal dispersion was 1–3%. CoPdA demonstrated high temperature H2 desorption and firmly held CO and carbonate species on the surface. SMSI operated on CoPdT even after contact with H2O and air. Metal surface reconstruction and increased formation of CH2 groups occurred during catalysis. At low pressure, CoPdT was more active, whereas CoPdA had higher CH4 selectivity. At high pressure, catalysis on CoPdA revealed dependence on Tred, synthesis of C2+ hydrocarbons, decreased CO2 production, and higher CH4/CO2 ratio. CO conversion decreased with time due to difficulties in the surface diffusion of reagents, intermediates, and products, and metal particle agglomeration.