Boosting Industrial‐Level CO2 Electroreduction of N‐Doped Carbon Nanofibers with Confined Tin‐Nitrogen Active Sites via Accelerating Proton Transport Kinetics

Abstract The development of highly efficient robust electrocatalysts with low overpotential and industrial‐level current density is of great significance for CO 2 electroreduction (CO 2 ER), however the low proton transport rate during the CO 2 ER remains a challenge. Herein, a porous N‐doped carbon nanofiber confined with tin‐nitrogen sites (Sn/NCNFs) catalyst is developed, which is prepared through an integrated electrospinning and pyrolysis strategy. The optimized Sn/NCNFs catalyst exhibits an outstanding CO 2 ER activity with the maximum CO FE of 96.5%, low onset potential of −0.3 V, and small Tafel slope of 68.8 mV dec −1 . In a flow cell, an industrial‐level CO partial current density of 100.6 mA cm −2 is achieved. In situ spectroscopic analysis unveil the isolated SnN site acted as active center for accelerating water dissociation and subsequent proton transport process, thus promoting the formation of intermediate *COOH in the rate‐determining step for CO 2 ER. Theoretical calculations validate pyrrolic N atom adjacent to the SnN active species assisted reducing the energy barrier for *COOH formation, thus boosting the CO 2 ER kinetics. A Zn‐CO 2 battery is designed with the cathode of Sn/NCNFs, which delivers a maximum power density of 1.38 mW cm −2 and long‐term stability.