Two-Dimensional SnO2 Nanosheets for Efficient Carbon Dioxide Electroreduction to Formate

The electrocatalytic reduction of CO2 to liquid fuels is a promising strategy to store the intermittent renewable energies into high-value chemicals. Here, two-dimensional SnO2 nanosheet (similar to 3 nm in thickness) materials were synthesized using the hydrothermal method and characterized as efficient electrocatalysts for CO2 reduction to formate. Compared to the monometallic Sn-based catalysts, the SnO2 nanosheet electrodes exhibit a much improved performance. A large current density of 471 mA cm(-2) for formate production and a high Faradaic efficiency of 94.2% are simultaneously achieved using a three-compartment microfluidic flow cell electrolyzer. These results set a new record for formate production among monometallic Sn-based catalysts for the CO2 electroreduction reaction. Density functional theory calculations reveal the intrinsic improvement in the performance by the SnO2 surface site over the metallic Sn site.