CO oxidation on supported platinum group metal (PGM) based nanoalloys

The oxidation of carbon monoxide is widely investigated for realistic and potential uses in energy production and environmental processes. As a probe reaction to the surface properties, it gives an insight into the relationship between the structure of active phase and catalytic performance. Noble metals alloyed with certain transition metals in the form of a nanoalloy exhibit enhanced catalytic activity for various reactions, especially when simultaneous activation of oxygen and CO is involved. This article highlights some of these insights into nanoalloy catalysts in which platinum group metal (PGM) is alloyed with a second and/or third transition metal (M/M′=Co, Fe, V, Ni, Ir, etc.), for catalytic oxidation of carbon monoxide in a gas phase. Recent studies have provided important insights into how the atomic-scale structures of the nanoalloy catalysts operate synergistically in activating oxygen and maneuvering surface oxygenated species. The exploration of atomic-scale chemical/structural ordering and coordination in correlation with the catalytic oxidation properties based on findings from ex- and in-situ synchrotron X-ray techniques is emphasized; for example, high-energy X-ray diffraction coupled to atomic-pair distribution function and X-ray absorption fine-structure spectroscopic analysis. The understanding of the detailed active sites of the nanoalloys has significant implications for the design of low-cost, active, and durable catalysts for sustainable energy production and environmental processes.