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

Cobalt-nitrogen-carbon (CoNC) 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 (CoMnNC) dual-site catalysts by incorporating Mn into CoNC 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 center in CoMnNC, *OOH activation on the surface is enhanced, and the two-electron ORR process is inhibited. Consequently, the CoMnNC catalyst exhibits excellent ORR activity (E = 0.76 V vs. reversible hydrogen electrode) and a very low hydrogen peroxide (HO) yield (<2.9 %) in acidic electrolyte. Additionally, the dynamic evolution of *OH on the Mn-N site confirms that Mn-N can serve as a potential catalytic site for the hydrogen peroxide reduction reaction (HPRR), facilitating HO decomposition. Differential electrochemical mass spectrometry (DEMS) demonstrates that this parallel catalytic pathway effectively weaks the oxidative corrosion of HO on the carbon carrier. The results indicate that the negative half-wave potential shift of CoMnNC 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.