Electrodeposited highly-oriented bismuth microparticles for efficient CO2 electroreduction into formate

Bi is one of the most fascinating catalysts for the formation of HCOO− towards CO2 electroreduction. Herein, we developed electrodeposited angular-shaped Bi microparticles (Bi MP) with exposed surfaces of {003} and {101} planes as efficient catalyst for the electroreduction of CO2 into HCOO−. During CO2 electroreduction, Bi MP achieved a Faraday efficiency (FE) for HCOO− of higher than 95% over a wide range of applied potential from −0.6 to −1.1 V versus reversible hydrogen electrode (vs. RHE), whereas the FE for HCOO− of Bi nanoflakes (Bi NF) with exposed surfaces of {104} and {110} planes was around 70%. At −1.1 V vs. RHE, the partial current density for HCOO− of Bi MP was −271.7 mA·cm−2, 1.56 times as high as that of Bi NF. According to kinetic analysis and mechanistic study, highly-oriented surface of Bi MP not only facilitated Faradaic process and accelerated reaction kinetics via enhancing the CO2 activation, but also restrained competing hydrogen evolution reaction, thus boosting catalytic performance of the electroreduction of CO2 into HCOO−.