Self-templated synthesis of hierarchical mesoporous SnO2 nanosheets for selective CO2 reduction

Abstract

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.