Hierarchical Heterostructure of SnO2 Confined on CuS Nanosheets for Efficient Electrocatalytic CO2 Reduction
CO2 direct electroreduction to ratio-tunable syngas (CO+H2) is an appealing solution to provide important feedstocks for many industrial processes. However, low-cost, earth-abundant yet efficient and stable electrocatalysts for composition-adjustable syngas is still unmet for practical applications. Herein, new hierarchical oD/2D heterostructures of SnO2 nanoparticles (NPs) confined on CuS nanosheets (NSs) were designed to enable CO2 electroreduction to a wide-range syngas (CO/H2: 0.11~3.86) with high Faradaic efficiency (>85 %), remarkable turnover frequency (96.12 h-1) and excellent durability (over 24 h). Detailed experimental characterizations together with theoretical calculations manifest that the ascendant catalytic performance is not only attributed to the heterostructure of ultrasmall SnO2 NPs homogeneously confined on ultrathin CuS NSs, which endows the maximum exposure of active sites and faster charge transfer, but also accounted for the strong interaction between well-defined SnO2 and CuS interfaces, which modulated reaction free-energies of reaction intermediates and hence improved activity of CO2 electroreduction to ratio-highly-tunable syngas. This work provides a better understanding and a new strategy of intermediate regulation by interface engineering of hereostructure for CO2 reduction and beyond.