Promotion of CO 2 Electroreduction on Bismuth Nanosheets with Cerium Oxide nanoparticles.

Formic acid (HCOOH) is a highly energy efficient product of the electrochemical CO 2 reduction reaction (CO 2 RR). Bismuth-based catalysts have shown promise in the conversion of CO 2 to formic acid, but there is still a great need for further improvement in selectivity and activity. Herein, we report the preparation of Bi nanosheets decorated by cerium oxide nanoparticles (CeO x ) with high Ce 3+ /Ce 4+ ratio and rich oxygen vacancies. The CeO x nanoparticles affect the electronic structures of bismuth, enhance CO 2 adsorption, and thus promote the CO 2 RR properties of Bi nanosheets. Compared with elemental Bi nanosheets, the hetero-structured CeO x /Bi nanosheets exhibit much higher activity over a wide potential window, showing a current density of 16.1 mA cm -2 with a Faradaic efficiency of 91.1% at -0.9 V vs. reversible hydrogen electrode.