Cooperativity between atoms in supported “Single-Atom Catalysts” and metal clusters

• Cooperativity and electron-transfer between metals and supports are key phenomena to understand the performance of SACs and small metal clusters. • Single-atom catalysts often require the support to actively participate in the reaction to achieve optimal catalytic performance. • Small amounts of metal clusters could be contributing to the catalysis by SACs. • SACs and metal clusters often show unique opportunities in terms of catalytic selectivity. • The high mobility of supported clusters and SACs makes operando work crucial.