Boron Dopant Modulated Electron Localization of Tin Oxide for Efficient Electrochemical CO ₂ Reduction to Formate

Abstract Sn‐based electrocatalysts have great economic potential in the reduction of CO ₂ to HCOOH, while they still suffer from low current density, dissatisfactory selectivity, and poor stability. Inspired by electronic modification engineering, boron‐doped SnO ₂ nanospheres (B‐SnO ₂ ) are successfully synthesized to achieve high‐efficiency CO ₂ reduction reaction (CO ₂ RR). It is found that the introduction of boron dopants can increase the number of active sites and facilitate the formation of the electron‐rich Sn sites in its structure, thus enhancing the activation of CO ₂ molecules and reducing the energy barrier of *OCHO intermediates on the SnO ₂ surface. Thus, the B‐doped SnO ₂ electrocatalyst exhibits a remarkable FE _HCOOH above 90% within a broad potential window of −0.7 to −1.3 V versus reversible hydrogen electrode (RHE) (600 mV) and obtains the maximum value of 95.1% (the partial current density of HCOOH is 42.35 mA cm ⁻² ) at −1 V versus RHE. In conclusion, this work provides a novel strategy for optimizing the intrinsic properties of electrocatalysts for CO ₂ RR by the method of tuning the electronic structure.