Determining the Effect of Cation (Ti/Zr) Doping in Bismuth Oxide for Electrochemical CO<sub>2</sub> Reduction to Formic Acid: A DFT Study
Balaji G. Ghule, Ji‐Hyun Jang
Abstract
First-principles-based density functional theory (DFT) calculations were used to explore the electrochemical CO 2 reduction (ECR) activity of cation-doped Bi 2 O 3 . We studied the ECR reaction over pure and doped Bi 2 O 3 (100) surfaces and demonstrated Gibbs free energy diagrams of HCOOH formation via COOH and HCOO pathways. Compared with pure bismuth oxide, doping can alter the rate-determining step and reduce the Gibbs free energy from 2.98 to 0.11 eV. The CO 2 reduction activity was found to be most productive on the TiZr–Bi 2 O 3 surface with onset potentials of −0.23 and 0.55 V via the COOH and HCOO pathways, respectively. The probability of CO formation through the ECR reaction was also investigated using Gibbs free energy calculations, and it was found that Bi 2 O 3, Ti–Bi 2 O 3, Zr–Bi 2 O 3, and TiZr–Bi 2 O 3 displayed insufficient ECR activity to produce CO. We also compared the selectivity of the ECR reaction and the hydrogen evolution reaction (HER) to demonstrate the practicality of the electrocatalysts.