Spherical Boron Nitride Supported Gold–Copper Catalysts for the Low-Temperature Selective Oxidation of Ethanol

The oxidation of ethanol to acetaldehyde in the fine-chemical industry is a burgeoning process that requires leading-edge technology. A major challenge is to find a catalyst with high ethanol conversion and high acetaldehyde selectivity at a high gas hourly space velocity (GHSV) and a low operation temperature. Boron nitride nanosphere supported Au–Cu nanoparticles offer much opportunity for low-temperature ethanol oxidation. A catalytic ethanol conversion of 77 % and a selectivity of 94 % towards acetaldehyde were achieved at a temperature of 180 °C and a high GHSV of 100 000 mL g_cat⁻¹ h⁻¹, values that far exceed those obtained with Au–Cu/SiO₂. The immobilized Au–Cu nanoparticles have an average size of approximately 3 nm, and the majority of Au species are assigned Au^δ−. The weak interaction of acetaldehyde with both Au–Cu active phases and the boron nitride support facilitates the adsorption–desorption behavior of acetaldehyde. As a result, the progression of secondary reactions is slowed and the degree of coverage of the active sites is minimized.