Hierarchical heterostructure of SnO2 confined on CuS nanosheets for efficient electrocatalytic CO2 reduction

Abstract

The direct electroreduction of CO₂ 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 have still not been realized for practical applications. Herein, new hierarchical 0D/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 characterization studies 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 is also accounted by the strong interaction between well-defined SnO₂ and CuS interfaces, which modulated reaction free-energies of reaction intermediates and hence improved the activity of CO₂ electroreduction to highly ratio-tunable syngas. This work provides a better understanding and a new strategy for intermediate regulation by interface engineering of hereostructures for CO₂ reduction and beyond.