Density functional theory study of methanol steam reforming on ZnO(100)

This study presents a comprehensive reaction network diagram outlining potential pathways in the methanol steam reforming (MSR) reaction (CH3OH + H2O -> CO2 + 3H2). The MSR process catalyzed by ZnO was systematically investigated using Density Functional Theory (DFT) calculations, focusing on the adsorption behavior of intermediates, as well as the kinetics and thermodynamics of the reaction. The results indicate that, on the ZnO (1 0 0) surface, where H2O dissociates and is adsorbed, the cleavage of O-H bond of CH3OH yields CH3O, which subsequently dehydrogenates to form HCHO. Then, HCHO reacts with OH to form H2COOH, bypassing direct desorption or decomposition into CHO. The continuous dehydrogenation of H2COOH results in high selectivity for CO2. However, on the ideal ZnO(1 0 0) surface, the HCHO intermediate tends to desorb as gaseous formaldehyde product. This study elucidates the catalytic mechanism of the MSR reaction on ZnO(1 0 0) and offers theoretical insights for designing ZnO-based catalysts.