Efficient Co2 Electroreduction to Formate Via Bi-Sn/Ceo2 Nanorod

Electrocatalytic CO2 reduction reaction (CO2RR) to produce formate is one effective route for CO2 neutralization and renewable energy storage. Developing efficient catalyst is crucial to enhance the Faradaic efficiency (FE) of formate and retard the competing H2 evolution reaction. Herein, we design Bi- and Sn-anchored CeO2 nanorods catalysts with the valance state and oxygen vacancy (Vo) concentration controllable for CO2RR by reduction treatment at different environment. The m-Bi1Sn2Ox/CeO2 with moderate H2 composition reduction condition and suitable Sn/Bi molar ratio achieves a remarkable FEformate of 87.7% at -1.18 V vs. RHE compared with other catalysts. Additionally, the selectivity of formate was maintained over 20 hrs with an outstanding FEformate of above 80% in 0.5 M KHCO3 electrolyte. The outstanding CO2RR performance was attributed to the highest surface Sn2+ concentration which improves the formate selectivity. Further, the electron delocalization effect between Bi, Sn, and CeO2 tunes electronic structure and Vo concentration, promoting the CO2 adsorption and activation as well as facilitating the formation of key intermediates HCOO* as evidenced by the in-situ attenuated total reflection infrared measurements and density functional theory calculations. This work provides an interesting measure for the rational design of efficient CO2RR catalysts via valance state and Vo concentration control