Boron Dopant Modulated Electron Localization of Tin Oxide for Efficient Electrochemical CO₂ Reduction to Formate

Sn-based electrocatalysts have great economic potential in the reduction of CO₂ to HCOOH, while they still suffer from low current density, dissatisfactory selectivity, and poor stability. Inspired by electronic modification engineering, boron-doped SnO₂ nanospheres (B-SnO₂ ) are successfully synthesized to achieve high-efficiency CO₂ reduction reaction (CO₂ 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 CO₂ molecules and reducing the energy barrier of *OCHO intermediates on the SnO₂ surface. Thus, the B-doped SnO₂ 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 CO₂ RR by the method of tuning the electronic structure.