Reduction of Pd/ZnO catalyst and its catalytic activity for steam reforming of methanol

The effect of reduction temperature of the coprecipitated 15.9%Pd/ZnO catalyst on the catalytic activity for steam reforming of methanol (SRM) was studied. Methanol conversion at 523 K reached a maximum of 41.6% with a CO₂ selectivity of 94.6% and an outlet CO concentration of 1.26% over the catalyst reduced at 523573 K. Methanol conversion first increased with increasing reduction temperature, remained constant (41.6%) at reduction temperatures of 523573 K, and then sharply decreased at above 573 K because of agglomeration of the PdZn alloy. CO₂ selectivity and outlet CO molar fraction depended on the presence of the PdZn alloy, and the crystallite size of the PdZn alloy affects methanol conversion. It is proposed that the PdZn alloy and PdZnO_1-x might catalyze the SRM reaction together.