Highly selective PdZn/ZnO catalysts for the methanol steam reforming reaction†
One major drawback in the production of clean hydrogen from methanol is the formation of carbon monoxide which can subsequently act as a poison in fuel cell applications. Here we report on PdZn/ZnO catalysts developed for the methanol steam reforming reaction which have a high selectivity towards carbon dioxide. The impregnation-based method we employ for synthesising the PdZn/ZnO catalyst involves excess Cl− anion addition to the metal chloride precursors which results in improved mixing of the metals. This subsequently leads to the formation of highly ordered PdZn alloy particles, which are responsible for high catalytic selectivity. This is contrary to the situation found for PdZn/ZnO catalysts prepared by more conventional impregnation techniques (i.e., without the addition of excess Cl− anions), where random alloy PdZn particles were generated which result in a lower selectivity to CO2.