Mechanistic Insights into Reactions between Gold-Based Materials and Dioxygen

Gold (Au) exhibits distinct reactivities with O₂ from the nanometer to atomic scales, whereas bulk Au is chemically inert. Since the discovery of catalytic reactivities in Au-based materials, including nanoparticles, molecular complexes, and nanoclusters (AuNCs), mechanistic insights into the interaction and reductive activation of O₂ by Au have been pursued by researchers. However, atomic-level understanding of the reaction mechanism remains elusive compared with that for other widely explored transition metal-O₂ systems. This article briefly discusses recent progress in clarifying the reaction mechanisms of Au-O₂ chemistry for homogeneous molecular Au complexes and atomically precise AuNCs. Research focuses on (1) O₂ activation by Au complexes without the distinct formation of conventional metal-hydride species, and (2) the application of kinetic analyses to the reaction of thiolate-protected AuNCs with O₂ to quantify parameters such as O₂-binding constants on the Au surface. These findings help elucidate both the Au-O₂ interaction and reductive activation of O₂, which are essential in catalytic systems using O₂ as a terminal oxidant that can contribute to the developments of ecofriendly oxidation Au-based catalysts with high performance.