Nanostructured Tin Catalysts for Selective Electrochemical Reduction of Carbon Dioxide to Formate

High surface area tin oxide nanocrystals prepared by a facile hydrothermal method are evaluated as electrocatalysts toward CO₂ reduction to formate. At these novel nanostructured tin catalysts, CO₂ reduction occurs selectively to formate at overpotentials as low as ∼340 mV. In aqueous NaHCO₃ solutions, maximum Faradaic efficiencies for formate production of >93% have been reached with high stability and current densities of >10 mA/cm² on graphene supports. The notable reactivity toward CO₂ reduction achieved here may arise from a compromise between the strength of the interaction between CO₂^•– and the nanoscale tin surface and subsequent kinetic activation toward protonation and further reduction.