Synergistic Effect of Grain Boundaries and Oxygen Vacancies on Enhanced Selectivity for Electrocatalytic CO2 Reduction

Abstract

AbstractDual‐engineering involved of grain boundaries (GBs) and oxygen vacancies (VO) efficiently engineers the material's catalytic performance by simultaneously introducing favorable electronic and chemical properties. Herein, a novel SnO2 nanoplate is reported with simultaneous oxygen vacancies and abundant grain boundaries (V,G‐SnOx/C) for promoting the highly selective conversion of CO2 to value‐added formic acid. Attributing to the synergistic effect of employed dual‐engineering, the V,G‐SnOx/C displays highly catalytic selectivity with a maximum Faradaic efficiency (FE) of 87% for HCOOH production at −1.2 V versus RHE and FEs > 95% for all C1 products (CO and HCOOH) within all applied potential range, outperforming current state‐of‐the‐art electrodes and the amorphous SnOx/C. Theoretical calculations combined with advanced characterizations revealed that GB induces the formation of electron‐enriched Sn site, which strengthens the adsorption of *HCOO intermediate. While GBs and VO synergistically lower the reaction energy barrier, thus dramatically enhancing the intrinsic activity and selectivity toward HCOOH.