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 (HO). In nature, enzymes containing manganese (Mn) centers can convert reactive oxygen species into HO. 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 HO selectivity of 95.8 %. Impressively, Mn CD/C continuously produced 0.1 M HO solution at 200 mA/cm for 50 h in the flow cell, with negligible loss in activity and HO 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.