Highly Efficient and Robust Au/MgCuCr2O4 Catalyst for Gas-Phase Oxidation of Ethanol to Acetaldehyde

Gold nanoparticles (AuNPs) supported on MgCuCr2O4-spinel are highly active and selective for the aerobic oxidation of ethanol to acetaldehyde (conversion 100%; yield similar to 95%). The catalyst is stable for at least 500 h. The unprecedented catalytic performance is due to strong synergy between metallic AuNPs and surface Cu+ species. X-ray photoelectron spectroscopy shows that Cu+ is already formed during catalyst preparation and becomes more dominant at the surface during ethanol oxidation. These Cu+ species are stabilized at the surface of the ternary MgCuCr2O4-spinel support. Further kinetic measurements indicate that the Cu+ species act as sites for O-2 activation.