The catalytic performance of single-atom catalysts (SACs) is vitally determined by their coordination environments. So far, the catalytic manipulation of SACs has been mainly focused on the first and second nearest coordination structures of the center atoms. We herein demonstrate that the chemical environments beyond the second coordination shells also significantly influence the catalytic behaviors of SACs. Our findings reveal that the presence of graphitic nitrogen can induce a shift of the O₂ reduction pathway on CoN₄C sites from an energy-conversion favorite 4e^– pathway to a H₂O₂-production desirable 2e^– pathway. The remote graphitic N tunes the electronic structure of Co from the lower-spin state to the higher-spin state, as proved by the zero-field cooling (ZFC) temperature-dependent magnetic susceptibility, which weakens the adsorption of O₂/*OOH, ultimately enhancing the selectivity toward H₂O₂. It is further revealed that the catalytic influence of graphitic N may be universally present in other SACs such as FeN₄C and MnN₄C. Impressively, the graphitic N-doped CoN₄C exhibits a high H₂O₂ Faraday efficiency (82%) in a flow cell, with a remarkable H₂O₂ yield of 0.096 mmol cm^–2 h^–1 for 200 h at 0.358 V (vs RHE), which is sufficient for many applications such as the electro-Fenton-like degradation of the malachite green and demonstrated the feasibility of H₂O₂ electrosynthesis.

https://pubs.acs.org/doi/10.1021/acscatal.4c00781