Halide-induced lattice disorder in bismuth nanosheets for industrial-current-density CO2-to-formate conversion under neutral condition

Abstract

Bi-based electrocatalysts emerged as promising candidates to achieve efficient CO2-to-formate conversion, but they still suffered from the unsatisfied formate activity under the neutral condition. Here, halide-induced lattice disorder sites in bismuth nanosheets were proposed to achieve industrial-current-density CO2-to-formate conversion under neutral condition. In-situ Raman spectra and in-situ X-ray diffraction patterns revealed that Cl− extraction led to the formation of abundant lattice disorder Bi active sites, which resulted in the comprehensive surface strains. In-situ Fourier transform infrared spectroscopy unveiled CO2•− was the key intermediate. Additionally, theoretical calculation indicated that the lattice strain induced by Cl− extraction increased the density of states near the Fermi level, which would benefit CO2 adsorption and accelerate rate-determine charge transfer step to form CO2•− intermediates. As a result, the BiOCl-derived Bi nanosheets with abundant lattice disorder exhibited remarkable formate Faradaic efficiency up to 98% under the industrial current density (>200 mA/cm2), and operated continuously for 120 h at 100 mA/cm2 under the neutral condition (pH=7).