Unveiling the Proton–Electron Transfer Pathway in Zn-Embedded N-Doped Carbon Catalyst for Enhanced CO2 Electroreduction

Proton–electron transfer (PET) processes play a pivotal role in numerous electrochemical reactions; yet, effectively harnessing them remains a formidable challenge. Consequently, unveiling the PET pathway is imperative to elucidate the factors influencing the efficiency and selectivity of small molecule electrochemical conversion. In this study, a Zn–NC model catalyst with N and C vacancies was synthesized using a hydriding method to investigate the universal impact of PET on CO2 electroreduction. The introduction of N vacancies induced the formation of a distinctive Zn–N3 topological structure and atomically populated Znδ+ sites with lower valence states, thereby facilitating the cleavage of the C═O bonds. Conversely, C vacancies led to the formation of stable C–H bonds and tuned the rate of dissociation of H2O to H*. In comparison to sequential proton–electron transfer, concerted proton–electron transfer significantly enhanced the formation of *COOH species, a critical step in the CO2 reduction process on a Zn-enhanced N-doped carbon catalyst. The catalyst exhibited a remarkable 96% CO Faradaic efficiency at −0.36 V vs RHE. This research contributes to the ongoing endeavors to unlock the full potential of concerted proton–electron transfer in electrochemical synthesis and its application in sustainable energy and environmental solutions.