Nature-Inspired N, O Co-Coordinated Manganese Single-Atom Catalyst for Efficient Hydrogen Peroxide Electrosynthesis

The two-electron oxygen reduction reaction (2e^- ORR) is a pivotal pathway for the distributed production of hydrogen peroxide (H₂O₂). In nature, enzymes containing manganese (Mn) centers can convert reactive oxygen species into H₂O₂. However, Mn-based heterogeneous catalysts for 2e^- ORR are scarcely reported. Herein, we developed a nature-inspired single-atom electrocatalyst comprising N, O co-coordinated Mn sites, utilizing carbon dots as the modulation platform (Mn CD/C). As-synthesized Mn CD/C exhibited exceptional 2e^- ORR activity with an onset potential of 0.786 V and a maximum H₂O₂ selectivity of 95.8 %. Impressively, Mn CD/C continuously produced 0.1 M H₂O₂ solution at 200 mA/cm² for 50 h in the flow cell, with negligible loss in activity and H₂O₂ faradaic efficiency, demonstrating practical application potential. The enhanced activity was attributed to the incorporation of Mn atomic sites into the carbon dots. Theoretical calculations revealed that the N, O co-coordinated structure, combined with abundant oxygen-containing functional groups on the carbon dots, optimized the binding strength of intermediate *OOH at the Mn sites to the apex of the catalytic activity volcano. This work illustrates that carbon dots can serve as a versatile platform for modulating the microenvironment of single-atom catalysts and for the rational design of nature-inspired catalysts.