Self-templated synthesis of hierarchical mesoporous SnO2 nanosheets for selective CO2 reduction
Electrocatalytic CO2 reduction to formic acid or formate is desirable but challenging due to the lack of effective and selective electrocatalysts. Among the potential candidates, Sn-based materials have attracted wide attention, but most of them, unfortunately, do not achieve high formate selectivity until at very large overpotentials. Herein, we report the self-templated synthesis of mesoporous SnO2 nanosheets as the high-performance electrocatalyst for CO2 reduction. The final product features large surface area, abundant mesoporosity and three-dimensional hierarchical order, which are beneficial for electrochemical applications. When evaluated as the CO2 reduction electrocatalyst, mesoporous SnO2 nanosheets exhibit small onset potential, large cathodic current density, high faradaic efficiency and great stability for formate production. It is most impressive that a high formate faradaic efficiency of 83% is achieved at η ∼ 710 mV, about 150–300 mV less than that discussed in previous literature results. Moreover, we integrate mesoporous SnO2 with a dimensionally stable anode, and achieve battery-driven CO2/H2O splitting to formate/O2 with decent conversion efficiency.