Solar energy powered electrochemical reduction of CO2 on In2O3 nanosheets with high energy conversion efficiency at a large current density

Electrochemical CO 2 reduction (ECO 2 R) to value-added chemicals offers a promising approach to both mitigate CO 2 emission and facilitate renewable energy conversion. We demonstrate a solar energy powered ECO 2 R system operating at a relatively large current density (57 mA cm −2 ) using In 2 O 3 nanosheets (NSs) as the cathode and a commercial perovskite solar cell as the electricity generator, which achieves the high solar to formate energy conversion efficiency of 6.6 %. The significantly enhanced operative current density with a fair solar energy conversion efficiency on In 2 O 3 NSs can be ascribed to their high activity and selectivity for formate production, as well as the fast kinetics for ECO 2 R. The Faradic efficiencies (FEs) of formate In 2 O 3 NSs are all above 93 %, with the partial current density of formate ranging from 2.3 to 342 mA cm −2 in a gas diffusion flow cell, which is among the widest for formate production on In-based catalysts. In-situ Raman spectroscopy and density functional theory simulations reveal that the exceptional performances of formate production on In 2 O 3 NSs originates from the presence of abundant low coordinated edge sites, which effectively promote the selective adsorption of *OCHO while inhibiting *H adsorption.