Supported Metal Clusters: Fabrication and Application in Heterogeneous Catalysis

Different from isolated metal atoms and large metal nanoparticles (NPs), supported metal clusters (SMCs) possess distinct geometric and electronic structures and thus exhibit enhanced activity and designated selectivity in catalysis. So far, with the development in synthetic methodologies and characterization techniques, SMCs with fine structures could be constructed and well-defined at the atomic level. In addition, based on computational modeling of SMCs, theoretical calculations corroborated well with experimental results, providing in-depth insights into the structure–property relationship for SMCs in catalysis. In this Review, classic synthetic strategies and key characterization techniques of SMCs are summarized. Subsequently, the applications of SMCs in important catalytic reactions based on recent studies are discussed, including aerobic oxidation, hydrogenation, dehydrogenation, water–gas shift (WGS) reaction, and photocatalytic reactions. In particular, the importance of the cluster size-effect and metal–support interactions in determining the catalytic performance of SMCs is highlighted. Lastly, challenges and prospects in SMCs' catalysis are illustrated.