Improvement of oxygen evolution activity on isolated Mn sites by dual-heteroatom coordination

The coordination of dual-heteroatom is an effective strategy to enhance the performance of oxygen evolution reaction (OER) of single-atom catalysts. Here, we synthesize Mn-SG-500 with isolated Mn sites coordinated with two sulfur and two oxygen atoms on graphene, and perform in-depth research on the structure-activity relationship for the OER. Under alkaline conditions, the Mn-SG-500 displays higher OER activity than commercial RuO2. Combining in-situ structure analysis and theoretical calculations, we identify Mn-S2O2 as the catalytic active center, on which the oxidation of *O to *OOH is the rate-control step. The improved OER activity is attributed to the redistribution and optimization of Mn charges caused by the co-coordination of S and O. This work is helpful for further structure design and performance management of single-atom catalysts with dual-heteroatom doping.