Effect of Calcination Temperature of Support on the Performance of Co-Mo/MgO-Al2O3 Water-Gas Shift Catalyst

The effect of calcination temperature of the MgO-Al2O3 mixed oxide support on the physicochemical properties of the support and the performance of the Co-Mo-based water-gas shift catalyst was studied by means of X-ray diffraction , N2 adsorption-desorption, tempera- ture-programmed desorption, temperature-programmed reduction, and electron paramagnetic resonance. The activity testing results showed that the catalysts with the mixed oxide supports calcined at 600-800 oC exhibited high activity for the reaction. The physicochemical charac- terization results indicated that MgO-Al2O3 mixed oxide supports calcined at 600-800 oC existed as amorphous compound MgAl2O4- xMgO-yAl2O3, on which more middle strength acid-base sites were formed. For the Co-Mo/MgO-Al2O3 catalysts in oxidation state, more octahedral Mo species were found, while more oxysulfo-Mo 5+ species were detected on the sulfurized catalysts. These species were closely