Inhibiting carbon corrosion of cobalt-nitrogen-carbon materials via Mn sites for highly durable oxygen reduction reaction in acidic media

Cobalt-nitrogen-carbon (CoN_xC) materials are regarded as promising low-cost electrocatalysts for the oxygen reduction reaction (ORR). However, their susceptibility to deactivation and poor stability in acidic media limits their practical applications. In this study, we develop cobalt (Co) and manganese (Mn) embedded in nitrogen-doped carbon (CoMnN_xC) dual-site catalysts by incorporating Mn into CoN_xC and leverage a synergistic dual-catalysis strategy to optimize both activity and stability. The dynamic evolution of *OOH intermediate on the catalyst surface is monitored via in situ Raman spectroscopy, confirming that Mn introduction modulates the reaction pathway. Due to electron transfer from Mn to the Co-N_x center in CoMnN_xC, *OOH activation on the surface is enhanced, and the two-electron ORR process is inhibited. Consequently, the CoMnN_xC catalyst exhibits excellent ORR activity (E_1/2 = 0.76 V vs. reversible hydrogen electrode) and a very low hydrogen peroxide (H₂O₂) yield (<2.9 %) in acidic electrolyte. Additionally, the dynamic evolution of *OH on the Mn-N_x site confirms that Mn-N_x can serve as a potential catalytic site for the hydrogen peroxide reduction reaction (HPRR), facilitating H₂O₂ decomposition. Differential electrochemical mass spectrometry (DEMS) demonstrates that this parallel catalytic pathway effectively weaks the oxidative corrosion of H₂O₂ on the carbon carrier. The results indicate that the negative half-wave potential shift of CoMnN_xC catalysts in acidic electrolyte after 10,000 accelerated durability tests (ADT) is only 11 mV. The synergistic dual-catalytic strategy proposed in this work offers a novel approach for designing high-efficiency and stable transition metal-nitrogen-carbon catalysts.