In Situ Reconstruction of a Hierarchical Sn-Cu/SnOx Core/Shell Catalyst for High-Performance CO2 Electroreduction

The electrochemical CO2 reduction reaction (CO2RR) to give C-1 (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 Sn2.7Cu catalyst with a hierarchical Sn-Cu core can be reconstructed in situ under cathodic potentials of CO2RR. The resulting Sn2.7Cu catalyst achieves a high current density of 406.7 +/- 14.4 mA cm(-2) with C-1 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 C-1 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 C-1 products by suppressing the competitive hydrogen evolution reaction, resulting in high Faradaic efficiency, current density, and stability of CO2RR at low overpotentials.