Industrial-current-density CO2-to-formate conversion with low overpotentials enabled by disorder-engineered metal sites

CO2 electroreduction to formate is technically feasible and economically viable, but still suffers from low selectivity and high overpotential at industrial current densities. Here, lattice-distorted metallic nanosheets with disorder-engineered metal sites are designed for industrial-current-density CO2-to-formate conversion at low overpotentials. As a prototype, richly lattice-distorted bismuth nanosheets are first constructed, where abundant disorder-engineered Bi sites could be observed by high-angle annular dark-field scanning transmission electron microscopy image. In-situ Fourier-transform infrared spectra reveal the CO2•−* group is the key intermediate, while theoretical calculations suggest the electron-enriched Bi sites could effectively lower the CO2 activation energy barrier by stabilizing the CO2•−* intermediate, further affirmed by the decreased formation energy from 0.49 to 0.39 eV. As a result, the richly lattice-distorted Bi nanosheets exhibit the ultrahigh current density of 800 mA·cm−2 with 91% Faradaic efficiencies for CO2-to-formate electroreduction, and the formate selectivity can reach nearly 100% at the current density of 200 mA·cm−2 with a very low overpotential of ca. 570 mV, outperforming most reported metal-based electrocatalysts.