Indium oxide induced electron-deficient indium hollow nanotubes for stable electroreduction of CO2 at industrial current densities

Despite high selectivity for CO2 electroreduction to formate, the current density and stability over indium-based catalysts are far from the requirements of industrial applications. Herein, we report an aminated In-MOF-derived In/In2O3 hollow nanotube catalyst (In/In2O3 Ho-nt), which can maintain a stable In-0/In3+ heterostructure during the CO2 electrocatalysis. The stable In-0/In3+ species boosts the formate FE (Faradaic efficiency) to over 90% with a highest current density of similar to 650 mA cm(-2) in a wide potential range from 0.8 V to 1.2 V vs. RHE in flow cells. More impressively, In/In2O3 Ho-nt demonstrates a full-cell EE (energy efficiency) of 44.5% and a long-term stability of 70 h at a current density of 200 mA cm(-2) in membrane electrode assembly (MEA) cells by controlling the hydrophobicity of the catalyst interface. DFT calculations reveal that the charge redistribution between In3+ and In-0 sites endows In-0 sites with an electron-deficient environment, which enhances the adsorption capacity of CO2* intermediate and accelerates charge transfer kinetics, thus improving the activity of CO2 electroreduction to formate.