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.

Synthesis of methanol from CO 2 hydrogenation is a highly attractive route for recycling greenhouse gases to produce clean and value-added fuels and chemicals, simultaneously mitigating the CO 2 emission and obtaining useful feedstock. Heterogeneous catalysts have been the pillar for CO 2 catalytic transformation. The strong metal−support interaction (SMSI) is of great importance for supported catalysts. In addition, the SMSI can be used to enhance the catalytic activity and selectivity to the desired product as well as the stability of the catalysts. Understanding the SMSI is the key to gain deep insights into the structure−activity relationship, which provides valuable guideline for rational design of highly efficient and selective catalysts for methanol synthesis from CO 2 hydrogenation. In this review, we present an overview of the advances of CO 2 reduction to methanol with focus on catalytic performance, structure characterization, and reaction mechanism for rational design of desired catalysts.

Herein we report an efficient and recyclable catalytic system for tandem CO2 capture and N‐formylation to value‐added chemicals. CO2 is apt to be captured by morpholine solution, while a highly efficient heterogeneous catalyst, isolated iridium atoms supported over nanadiamond/graphene, is discovered to be highly reactive for the formylation of morpholine, leading to the formation of N‐formylmorpholine with excellent productivity (with a turnover number of 5 120 000 in a single batch reaction) and selectivity (>99 %). In addition, the CO2 captured by morpholine under atmospheric conditions can be converted to N‐formylmorpholine with decent conversion (51 %), which realizes the integration of CO2 capture and conversion to value‐added chemicals.