Densely packed ultrafine SnO2 nanoparticles grown on carbon cloth for selective CO2 reduction to formate

Electrochemical reduction of CO2 to fuels and chemicals is a viable strategy for CO2 utilization and renewable energy storage. Developing free-standing electrodes from robust and scalable electrocatalysts becomes highly desirable. Here, dense SnO2 nanoparticles are uniformly grown on three-dimensional (3D) fiber network of carbon cloth (CC) by a facile dip-coating and calcination method. Importantly, Zn modification strategy is employed to restrain the growth of long-range order of SnO2 lattices and to produce rich grain boundaries. The hybrid architecture can act as a flexible electrode for CO2-to-formate conversion, which delivers a high partial current of 18.8 mA cm−2 with a formate selectivity of 80% at a moderate cathodic potential of −0.947 V vs. RHE. The electrode exhibits remarkable stability over a 16 h continuous operation. The superior performance is attributed to the synergistic effect of ultrafine SnO2 nanoparticles with abundant active sites and 3D fiber network of the electrode for efficient mass transport and electron transfer. The sizeable electrodes hold promise for industrial applications.