Single-Atom Mn Catalysts via Integration with Mn Sub Nano-Clusters Synergistically Enhance Oxygen Reduction Reaction.

Integrating single atoms and clusters into one system represents a novel strategy for achieving the desired catalytic performance. In comparison to single-atom catalysts, catalysts combining single atoms and clusters harness the advantages of both, thus displaying greater potential. Nevertheless, constructing single-atom-cluster systems remains challenging, and the fundamental mechanism for enhancing catalytic activity remains elusive. In this study, a directly confined preparation of a 3D hollow sea urchin-like carbon structure (Mn SA /Mn AC -SSCNR) is developed. Mn single atoms synergistically interact with Mn clusters, optimizing and reducing energy barriers in the reaction pathway, thus enhancing reaction kinetics. Consequently, in contrast to Mn single-atom catalysts (Mn SA -SSCNR), Mn SA /Mn AC -SSCNR exhibits significantly improved oxygen reduction activity, with a half-wave potential (E 1/2 ) of 0.90 V in 0.1 m KOH, surpassing that of Mn SA -SSCNR and Pt/C. This work demonstrates a strategy of remote synergy between heterogeneous single atoms and clusters, which not only contributes to electrocatalytic reactions but also holds potential for reactions involving more complex products.