The Key Role of Support Surface Hydrogenation in the CH4 to CH3OH Selective Oxidation by a ZrO2-Supported Single-Atom Catalyst

Direct conversion of methane to methanol has attracted much interest and yet remains a challenge. Here, we investigate the catalytic mechanisms for methane oxidation on the Rh single-atom catalyst (SAC) dispersed on zirconia support Rh-1/ZrO2 by first-principles calculations. We find that, by comparison with other metal SACs dispersed on ZrO2, the spontaneous dissociative adsorption of H2O2 on the Rh-1/ZrO2 surface is a key factor that initiates the active site and hydrogenates the surrounding oxide support surface. We further reveal that the hydrogenation of the oxide support surface plays a key role in suppressing the further production of CH3OOH and CO2. Additionally, we propose a non-noble-metal Fe-1/ZrO2 SAC as an active and selective catalyst for direct CH4 to CH3OH conversion, potentially performing better than the current best Rh-1/ZrO2 SAC. Our findings provide insights for the design of highly selective and efficient catalysts for direct CH4 to CH3OH conversion.