Unveiling\nthe Proton–Electron Transfer Pathway\nin Zn-Embedded N‑Doped Carbon Catalyst for Enhanced CO<sub>2</sub> Electroreduction

Proton–electron\ntransfer (PET) processes play a pivotal\nrole in numerous electrochemical reactions; yet, effectively harnessing\nthem remains a formidable challenge. Consequently, unveiling the PET\npathway is imperative to elucidate the factors influencing the efficiency\nand selectivity of small molecule electrochemical conversion. In this\nstudy, a Zn–NC model catalyst with N and C vacancies was synthesized\nusing a hydriding method to investigate the universal impact of PET\non CO<sub>2</sub> electroreduction. The introduction of N vacancies\ninduced the formation of a distinctive Zn–N<sub>3</sub> topological\nstructure and atomically populated Zn<sup>δ+</sup> sites with\nlower valence states, thereby facilitating the cleavage of the CO\nbonds. Conversely, C vacancies led to the formation of stable C–H\nbonds and tuned the rate of dissociation of H<sub>2</sub>O to H*.\nIn comparison to sequential proton–electron transfer, concerted\nproton–electron transfer significantly enhanced the formation\nof *COOH species, a critical step in the CO<sub>2</sub> reduction\nprocess on a Zn-enhanced N-doped carbon catalyst. The catalyst exhibited\na remarkable 96% CO Faradaic efficiency at −0.36 V vs RHE.\nThis research contributes to the ongoing endeavors to unlock the full\npotential of concerted proton–electron transfer in electrochemical\nsynthesis and its application in sustainable energy and environmental\nsolutions.