Surface Oxygen Defect Engineering of A2B2O7 Pyrochlore Semiconductors Boosts the Electrocatalytic Reduction of CO2‐to‐HCOOH

Abstract

AbstractThe electrocatalytic conversion of inert CO2 to value‐added chemical fuels powered by renewable energy is one of the benchmark approaches to address excessive carbon emissions and achieve carbon‐neutral energy restructuring. However, the adsorption/activation of supersymmetric CO2 is facing insurmountable challenges that constrain its industrial‐scale applications. Here, this theory‐guided study confronts these challenges by leveraging the synergies of bimetallic sites and defect engineering, where pyrochlore‐type semiconductor A2B2O7 is employed as research platform and the conversion of CO2‐to‐HCOOH as the model reaction. Specifically, defect engineering intensified greatly the chemisorption‐induced CO2 polarization via the bimetallic coordination, thermodynamically beneficial to the HCOOH production via the *HCO2 intermediate. The optimal V‐BSO‐430 electrocatalyst with abundant surface oxygen vacancies achieved a superior HCOOH yield of 116.7 mmol h−1 cm−2 at −1.2 VRHE, rivalling the incumbent similar reaction systems. Furthermore, the unique catalytic unit featured with a Bi1‐Sn‐Bi2 triangular structure, which is reconstructed by defect engineering, and altered the pathway of CO2 adsorption and activation to allow the preferential affinity of the suspended O atom in *HCO2 to H. As a result, V‐BSO‐430 gave an impressive FEHCOOH of 93% at −1.0 VRHE. This study held promises for inspiring the exploration of bimetallic materials from the massive semiconductor database.