In Situ Reconstruction of a Hierarchical Sn‐Cu/SnOxCore/Shell Catalyst for High‐Performance CO₂Electroreduction

The electrochemical CO₂ reduction reaction (CO₂ RR) to give C₁ (formate and CO) products is one of the most techno-economically achievable strategies for alleviating CO₂ emissions. Now, it is demonstrated that the SnOx shell in Sn2.7 Cu catalyst with a hierarchical Sn-Cu core can be reconstructed in situ under cathodic potentials of CO₂ RR. The resulting Sn2.7 Cu catalyst achieves a high current density of 406.7±14.4 mA cm⁻² with C₁ Faradaic efficiency of 98.0±0.9 % at -0.70 V vs. RHE, and remains stable at 243.1±19.2 mA cm⁻² with a C₁ Faradaic efficiency of 99.0±0.5 % for 40 h at -0.55 V vs. RHE. DFT calculations indicate that the reconstructed Sn/SnOx interface facilitates formic acid production by optimizing binding of the reaction intermediate HCOO* while promotes Faradaic efficiency of C₁ products by suppressing the competitive hydrogen evolution reaction, resulting in high Faradaic efficiency, current density, and stability of CO₂ RR at low overpotentials.