Co-catalytic metal-support interactions in single-atom electrocatalysts

Single-atom catalysts (SACs) are advantageous because every active atom is exposed at the surface, ensuring maximum utilization of catalytically active metals. To optimize the effectiveness of SACs, every atomic site needs to contribute to an accelerated reaction and retain this performance over extended use. The state-of-the-art approach for optimizing the catalytic properties of these atomic sites is through metal-support interactions. In this Review, we present the concept of co-catalytic interactions, in which both the single atom and the support are directly involved in catalysis by binding intermediates to enhance and alter the reaction mechanism. The power of this concept is highlighted for a range of important electrocatalytic reactions. First, we investigate the role of single atoms and supports in the reaction mechanism and explore the SAC designs that have successfully enhanced performance. We then discuss the synthetic targets and strategies for producing SACs that achieve co-reactant, functional group or intermediate binding for co-catalyst metal-support interactions. Finally, we offer a perspective on the future of SAC research and on the opportunities in co-catalytic metal-support interactions to further elevate electrocatalytic performance. Single-atom catalysts benefit from metal-support interactions that enable the support to be directly involved in the reaction, accelerating specific mechanistic steps to obtain unique electrocatalytic properties. This Review discusses state-of-the-art techniques for synthesizing active co-catalytic single-atom structures and explores the design strategies that enhance their catalytic performance.