Uncovering Dynamic Edge‐Sites in Atomic Co−N−C Electrocatalyst for Selective Hydrogen Peroxide Production

Abstract Understanding the nature of single‐atom catalytic sites and identifying their spectroscopic fingerprints are essential prerequisites for the rational design of target catalysts. Here, we apply correlated in situ X‐ray absorption and infrared spectroscopy to probe the edge‐site‐specific chemistry of Co−N−C electrocatalyst during the oxygen reduction reaction (ORR) operation. The unique edge‐hosted architecture affords single‐atom Co site remarkable structural flexibility with adapted dynamic oxo adsorption and valence state shuttling between Co (2−δ)+ and Co 2+ , in contrast to the rigid in‐plane embedded Co 1 −N x counterpart. Theoretical calculations demonstrate that the synergistic interplay of in situ reconstructed Co 1 −N 2 ‐oxo with peripheral oxygen groups gives a rise to the near‐optimal adsorption of *OOH intermediate and substantially increases the activation barrier for its dissociation, accounting for a robust acidic ORR activity and 2e − selectivity for H 2 O 2 production.