Supported Sub‐Nanometer Clusters for Electrocatalysis Applications

Abstract Single‐atom catalysts (SACs) have attracted great attention in the field of electrocatalysis due to their exceptional activity, selectivity, 100% atom utilization, and tailorability of active sites at atomic level. The metal–support interactions and interatomic synergies, however, are severely limited due to the isolation of active sites in SACs which hinder their applications in some complex reactions. To this end, supported sub‐nanometer cluster catalysts (SNCCs, <2 nm) with nearly fully exposed active atoms may outperform the SACs in some specific catalytic reactions. The presence of abundant chemical bonds in the clusters can flexibly regulate the support–cluster interaction and build ensemble effect in the sub‐nanometer clusters for different electrocatalysis applications. In this review, recent advances of supported SNCCs in electrocatalysis applications are summarized and discussed for the first time. In particular, the importance of the support–cluster interactions and ensemble effect of the clusters in determining the catalytic performance of SNCCs are highlighted. Lastly, challenges and opportunities in SNCCs electrocatalysis are prospected.