Highly Efficient CO2 Reduction at Steady 2 A cm−2 by Surface Reconstruction of Silver Penetration Electrode

Electroreduction of CO2 to CO is a promising route for greenhouse gas resource utilization, but it still suffers from impractical current density and poor durability. Here, a nanosheet shell (NS) vertically standing on the Ag hollow fiber (NS@Ag HF) surface formed by electrochemical surface reconstruction is reported. As‐prepared NS@Ag HF as a gas penetration electrode exhibited a high CO faradaic efficiency of 97% at an ultra‐high current density of 2.0 A cm−2 with a sustained performance for continuous >200 h operation. The experimental and theoretical studies reveal that promoted surface electronic structures of NS@Ag HF by the nanosheets not only suppress the competitive hydrogen evolution reaction but also facilitate the CO2 reduction kinetics. This work provides a feasible strategy for fabricating robust catalysts for highly efficient and stable CO2 reduction. Highly efficient CO2 electroreduction is achieved over silver penetration electrode based on the synergetic combination of the unique penetration effect as well as the tuned electronic structure by reconstructed nanosheet‐standing shell, with a high CO faradaic efficiency of 97% at an ultra‐high current density of 2.0 A cm−2 and sustained performance for continuously >200 h operation.