▎ 摘　　要

Nanostructured Bi2O3 electrocatalysts for electrochemical reduction of CO2 (CO2ER) into formic acid (HCOOH) hold great promise due to low toxicity and inexpensive cost, but are still confronted with poor catalytic per-formance in the high overpotential region. Herein, the polyethylene oxide-engineered reduced graphene oxide (p-rGO) with rich mesopores was designed as the support of Bi2O3 nanoparticles for the efficient CO2ER to HCOOH. The resultant Bi2O3/p-rGO electrocatalyst delivered an outstanding faradaic efficiency of 94.3% with a competitive current density of-16.8 mA cm-2 at-1.09 VRHE, and maintained the faradaic efficiency above 90% over a wide potential range (-0.99 to-1.29 VRHE). The advanced performance of Bi2O3/p-rGO could be attributed to the integrated contributions of the unique mesoporous structure and the favorable support effect between p-rGO and Bi2O3. This work may provide a new design for the construction of metal/metal oxide on mesoporous reduced graphene to develop high-performance electrocatalysts for CO2ER.