Bi-Doped In2O3 Nanofiber for Efficient Electrocatalytic CO2 Reduction

Abstract

Electrocatalytic carbon dioxide reduction reaction (CO₂RR) to formic acid (HCOOH) is attracted for superfluous CO₂ removal and HCOOH production under ambient conditions. Indium-based catalysts has considered as a good candidate material for CO₂RR to HCOOH due to their environmentally friendly features. However, the catalytic efficiency is limited by the poor HCOOH Faradaic efficiency (FE) and high reaction overpotential of electrocatalyst, and the activity and stability of indium-based catalysts are unsatisfactory, especially in industrial current density that is critical for commercialization. Herein, a fiber Bi-doped In₂O₃ was synthesized through electrospinning method, and it demonstrate a FE_HCOOH of 88.2% at −1.5 V versus RHE (reversible hydrogen electrode) with partial current density of −21.8 mA cm⁻² in H type cell. Specially, the Bi-In electrocatalyst also reach the industrial current density standard, which can work at −400 mA cm⁻² current density with FE_HCOOH of 92.7% (yield of HCOOH is 6.9 mmol h⁻¹) in home-made Flow cell. Importantly, Bi-In shows 24 h long-term stability test in −300 mA cm⁻². The improvement catalytic activity of Bi-In catalyst is ascribed to the optimized electronic structure of In site, and the reduced work function value of Bi-In is beneficial for reducing the formation energy of the key *OCHO intermediates.