Surface modification of SnO2 nanosheets via ultrathin N-doped carbon layers for improving CO2 electrocatalytic reduction

For CO2 electrocatalytic reduction, it is highly challenging to activate CO2 at a low overpotential. Herein, we demonstrated to modify the surface properties of tin dioxide nanosheets loaded on carbon fibers via the partial coating of nitrogen-doped carbon (NC). The NC layers with Lewis base sites on SnO2 nanosheets would facilitate the surface adsorption and subsequent conversion of CO2 into formate. Therefore, the optimal electrocatalyst exhibits very high Faradic efficiency (>80%) in a broad potential range of −0.6 – −1.0 V (vs. RHE) with the maximum value up to 93% and good long-term stability for 24 h. Both experimental results and theoretical calculations firstly revealed that the improved performance would be attributed to the improved local CO2 concentration due to the surface modification of SnO2 nanosheets with NC. Therefore, the surface regulation of SnO2 plays a significant role in promoting the catalytic performance in CO2 electroreduction reaction.