Catalytic boosting on AuCu bimetallic nanoparticles by oxygen-induced atomic restructuring

Understanding the structure-activity relationship over silica-supported Au-based bimetallic nanocatalysts in CO oxidation is essential in elucidating active sites and catalytic mechanisms. Here, we uncover that structure-activity relationship over a silica-supported 10 nm sized AuCu bimetallic model nanocatalyst for CO oxidation. Oxygen–induced atomic restructuring of AuCu nanocrystals is comprehensively investigated using combined operando spectroscopic and microscopic techniques, including near-ambient-pressure X-ray photoelectron spectroscopy, diffuse reflectance infrared Fourier-transform spectroscopy, and environmental transmission electron microscopy. We show that the formation of CuO_x/Au heterostructure gives rise to the enhancement of catalytic activity for CO oxidation. The formation of the reactive heterostructure on catalysis was rationalized by density functional theory calculation. Our results indicate that intermediate heterostructure with a metal-oxide interface leads to strong electronic coupling between catalyst and support (i.e., electronic metal-support interaction effect).