Atomically Dispersed Co2 MnN8 Triatomic Sites Anchored in N-Doped Carbon Enabling Efficient Oxygen Reduction Reaction.

Abstract

Atomically dispersed transition metal-nitrogen/carbon (M-N/C) catalysts have emerged as the most promising substitutes to precious platinum counterparts toward oxygen reduction reaction (ORR). However, the reported M-N/C catalysts are usually in the form of common M-N4 moieties with only one single metal active site and suffer from insufficient activity. Herein, we elaborately developed an unusual trinuclear active structure with nitrogen-coordinated one Mn atom adjacent two Co atoms (Co2 MnN8 ) anchored in N-doped carbon as highly efficient ORR catalyst via adsorption-pyrolysis of bimetallic zeolitic imidazolate framework precursor. Atomic structural investigations and density functional theory (DFT) calculations revealed that Co2 MnN8 would experience a spontaneous OH binding to form Co2 MnN8 -2OH as the real active site, leading to a single electron-filled state in the orbital and an optimized binding energy of intermediates. Accordingly, the as-developed Co2 MnN8 /C exhibited an unprecedented ORR activity with a high half-wave potential of 0.912V and outstanding stability, not only surpassing the Pt/C catalyst but also representing a new record for the Co-based catalyst. This article is protected by copyright. All rights reserved.