Bismuth‐Oxide‐Decorated Graphene Oxide Hybrids for Catalytic and Electrocatalytic Reduction of CO2

Abstract Global warming challenges are fueling the demand to develop an efficient catalytic system for the reduction of CO 2 , which would contribute significantly to the control of climate change. Herein, as‐synthesized bismuthoxide‐decorated graphene oxide (Bi 2 O 3 @GO) was used as an electro/thermal catalyst for CO 2 reduction. Bi 2 O 3 @GO is found to be distributed uniformly, as confirmed by scanning electron and transmission electron microscopic analysis. The X‐ray diffraction (XRD) pattern shows that the Bi 2 O 3 has a β‐phase with 23.4 m 2 g −1 BET surface area. Significantly, the D and G bands from Raman spectroscopic analysis and their intensity ratio ( I D / I G ) reveal the increment in defective sites on GO after surface decoration. X‐ray photoelectron spectroscopic (XPS) analysis shows clear signals for Bi, C, and O, along with their oxidation states. An ultra‐low onset potential (−0.534 V vs. RHE) for the reduction of CO 2 on Bi 2 O 3 @GO is achieved. Furthermore, potential‐dependent (−0.534, −0.734, and −0.934 vs. RHE) bulk electrolysis of CO 2 to formate provides Faradaic efficiencies (FE) of approximately 39.72, 61.48, and 83.00 %, respectively. Additionally, in time‐dependent electrolysis at a potential of −0.934 versus RHE for 3 and 5 h, the observed FEs are around 84.20 % and 87.17 % respectively. This catalyst is also used for the thermal reduction of CO 2 to formate. It is shown that the thermal reduction provides a path for industrial applications, as this catalyst converts a large amount of CO 2 to formate (10 m m ).