A Highly Efficient Bi-based Electrocatalyst for the Reduction of CO2 to Formate

The electrochemical reduction of carbon dioxide (CO2) has received significant attention as a viable man-made carbon cycle able to replenish the natural carbon cycle. Although Bi-based materials are promising catalysts for the reduction of CO2 to formate, the effects of the morphology and the structure of these materials on their properties remain unclear. In this work, a nano Bi2O2CO3 (BOC) material was synthesized and subsequently calcined at 300, 400, and 500 degrees C to form three different Bi2O3 samples namely, Bi2O3-1, Bi2O3-2, and Bi2O3-3, respectively. Both the BOC and the calcined materials were decorated on glassy carbon electrodes and then reduced to metallic Bi to form r-BOC, r-Bi2O3-1, r-Bi2O3-2, and r-Bi2O3-3 samples. We compared the performance of the four reduced Bi-based catalysts towards the reduction of CO2 in an attempt to study the structure-activity relationship of Bi-based catalysts. r-Bi2O3-3 showed excellent catalytic performance towards the reduction of CO2 reduction to formate. Thus, this catalyst showed a faradaic efficiency (FE) for the electrochemical reduction of CO2 to formate as high as 95% at an overpotential of 0.99 V and with a current density of 17 mA cm(-2). r-Bi2O3-3 outperformed the rest of the reduced samples and most of the catalysts reported in the literature.