Regulating the Electronic Structure of Bismuth Nanosheets by Titanium Doping to Boost CO₂ Electroreduction and Zn–CO₂ Batteries

Abstract

Abstract The electrochemical carbon dioxide reduction reaction (E‐CO 2 RR) to formate is a promising strategy for mitigating greenhouse gas emissions and addressing the global energy crisis. Developing low‐cost and environmentally friendly electrocatalysts with high selectivity and industrial current densities for formate production is an ideal but challenging goal in the field of electrocatalysis. Herein, novel titanium‐doped bismuth nanosheets (TiBi NSs) with enhanced E‐CO 2 RR performance are synthesized through one‐step electrochemical reduction of bismuth titanate (Bi 4 Ti 3 O 12 ). We comprehensively evaluated TiBi NSs using in situ Raman spectra, finite element method, and density functional theory. The results indicate that the ultrathin nanosheet structure of TiBi NSs can accelerate mass transfer, while the electron‐rich properties can accelerate the production of *CO 2 − and enhance the adsorption strength of *OCHO intermediate. The TiBi NSs deliver a high formate Faradaic efficiency (FE formate ) of 96.3% and a formate production rate of 4032 µmol h −1 cm −2 at −1.01 V versus RHE. An ultra‐high current density of −338.3 mA cm −2 is achieved at −1.25 versus RHE, and simultaneously FE formate still reaches more than 90%. Furthermore, the rechargeable Zn–CO 2 battery using TiBi NSs as a cathode catalyst achieves a maximum power density of 1.05 mW cm −2 and excellent charging/discharging stability of 27 h.

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