Boosting electrochemical CO2 reduction by strong electronic interaction at the interface of Bi/SnO2 heterostructures

SnO 2 -based materials are promising electrocatalysts for the conversion of CO 2 to formate however increasing their activity further is challenging due to the suboptimal CO 2 adsorption and activation capacity. The interfacial engineering has proven effective in modulating the electronic structure and adsorption behavior of electrocatalysts. Herein, a heterostructure Bi/SnO 2 was constructed for the CO 2 electroreduction to formate in which a formate Faraday efficiency of 94.9 % and single-pass carbon efficiency of 40.3 % were achieved at −1.0 V versus reversible hydrogen electrode in 1.0 M KOH. During a 30-hour stability test, the current density was nearly constant without a significant decrease while the formate Faraday efficiency was maintained around 90 %. This remarkable activity is attributed to the strong electronic interaction arising from p–p orbital coupling at the Bi/SnO 2 interface, according to the experimental and theoretical investigations. The computational insights suggest that the p–p orbital coupling promotes the electron transfer from Bi to SnO 2 and optimizes the adsorption strength of the intermediate (*OCHO) to enhance the catalytic activity. The formation of *OCHO during formate generation was confirmed by the i n situ attenuated total reflectance surface-enhanced infrared absorption spectroscopy. This work might contribute key insights into the mechanisms underlying activity enhancement via strong electronic interaction between dual p- block metal catalysts.