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Electrochemical hydrogen peroxide (H2O2) production by the direct two-electron (2e) oxygen reduction reaction (ORR) has received much attention as a promising alternative to the industrially developed anthraquinone fabrication process. Transition metal (M) and nitrogen doped carbon (M–N–C, M = Fe or Co) catalysts are known to be active for four electron ORR pathways via two + two electron transfer, where the former is for the ORR and the latter for the peroxide reduction reaction (PRR). Here, we report mesoporous N-doped carbon/manganese hybrid electrocatalysts composed of MnO and Mn–Nx coupled with N-doped carbons (Mn–O/N@NCs), which have led to the development of electrocatalysis towards the 2e ORR route. Based on the structural and electrochemical characterization, the number of transferred electrons during the ORR on the Mn–O/N@NCs was found to be close to the theoretical value of the 2e process, indicating their high activity toward H2O2. The favored ORR process arose due to the increased number of Mn–Nx sites within the mesoporous N-doped carbon materials. Furthermore, there was a strong indication that the PRR is significantly suppressed by adjacent MnO species, demonstrating its highly selective production of H2O2 (>80%) from the oxygen electrochemical process. The results of a real fuel cell device test demonstrated that an Mn–O/N@NC catalyst sustains a very stable current, and we attributed its outstanding activity to a combination of site-dependent facilitation of 2e transfer and a favorable porosity for mass transport.

Graphical abstract: High-yield electrochemical hydrogen peroxide production from an enhanced two-electron oxygen reduction pathway by mesoporous nitrogen-doped carbon and manganese hybrid electrocatalysts

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