Support Crystal Plane Effects in the Steam Reforming of Alcohols on Pd/ZnO and Co/ZnO

Introduction The steam reforming of alcohols, particularly methanol and ethanol, presents a promising method of producing hydrogen. Due to its high activity at relatively low temperatures, Pd/ZnO has received attention as a methanol steam reforming (MSR) catalyst to produce H2 at very high CO2 selectivity. 1 Pd supported on most other materials dehydrogenates methanol to CO. Similarly, Co catalyzed ethanol steam reforming (ESR) exhibits very good activity and selectivity toward H2 when supported by ZnO, although the distinction between ZnO and other supports is not as pronounced as with the Pd/ZnO catalyzed MSR. The activation of the MSR pathway on Pd/ZnO has been attributed to the formation of PdZn alloys when reduced at high temperatures. While the incorporation of Zn into the Pd surface clearly alters the reaction energetics, it is not known if ZnO contributes a secondary effect. To assist in understanding the role of ZnO in the steam reforming of alcohols, we investigated the decomposition of methanol and ethanol on Pd and Co supported by ZnO single crystals. As part of a larger study to understand the role of ZnO, we focused on examining differences in catalyst reactivity of Pd and Co toward alcohol decomposition when supported