Highly selective oxidation of methane to methanol has long been challenging in catalysis. Here, we reveal the water-promoted selective tuning from carbon monoxide and carbon dioxide to methanol with the exposure of methane, oxygen, and water to a CeO2/Cu2O/Cu(111) model catalyst. Density functional theory (DFT) calculations and kinetic Monte Carlo (KMC) simulations showed that water preferentially dissociates over the active cerium ions at the CeO2–Cu2O/Cu(111) interface. The adsorbed hydroxyl species blocked O-O bond cleavage that would dehydrogenate methoxy groups to carbon monoxide and carbon dioxide, and it directly converted methane to methanol; while the only role of oxygen was to reoxidize the reduced surface. Water adsorption also helped methanol production by facilitating the desorption of the produced methanol to the gas phase. These results were consistent with ambient-pressure x-ray photoelectron spectroscopy (AP-XPS), which verified that water added to methane and oxygen led to surface methoxy groups and accelerated methanol production.

Water-promoted interfacial pathways in methane oxidation to methanol on a CeO2-Cu2O catalyst

ACS Fall 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.