Heterogeneous catalysis by gold and gold-based bimetal nanoclusters

Gold and gold-based bimetallic catalysts have shown great potential for many important chemical transformation reactions owing to their good activity and high selectivity under relatively mild conditions. However, elucidating their structure-property relationships remains a major challenge because of size distributions and ill-defined structures (i.e. structural heterogeneity) of conventional nanoparticle catalysts. Recently, controlled synthesis of homogold and gold-based bimetal nanoclusters with precise atom numbers have been accomplished, and more importantly their atomic structures have been elucidated, which provide new model systems for understanding the catalytic behavior at the atomic level. Due to their ultra-small size, gold and bimetal nanoclusters exhibit unique properties, which contribute to novel catalysts or precatalysts for many chemical reactions. Herein, we review the recent progress in the catalytic research of atomically precise gold and gold-based bimetal nanoclusters. Specifically, this review covers the application of nanoclusters with or without ligands as catalysts for reactions such as selective oxidation, selective hydrogenation, C–C coupling and photocatalysis. Finally, we provide some future perspectives about metal nanocluster catalysis.