Construction of a flower-like SnS2/SnO2 junction for efficient photocatalytic CO2 reduction

Photoreduction of CO2 to value-added chemicals and fuels is an attractive solution to alleviate environmental problems and energy crisis at the same time. However, engineering efficient photocatalysts with high activity and product selectivity is still challenging. Herein, we achieved three-dimensional (3D) spatial configuration design at micro-scale and heterogeneous interface construction at nano-scale on a SnS2/SnO2 composite, which featured hierarchical flower-like morphology consisted of nanosheets and type-II semiconductor structure. It behaved excellent selectivity and impressive photocatalytic CO2-to-CO performance with a yielding rate of 60.85 μmol g-1h-1, roughly 3 times higher than that of SnS2 and was in the front rank of this kind catalysts under 300 W Xe lamp illumination without using any sensitizers or noble metals. The enhanced catalytic capability could be attributed to the elaborately built structure with suitable energetic position that afforded effective separation and migration of photo-generated electron/hole pairs as well as enhanced light caption and absorption. Meanwhile, main reactive intermediates (e.g., CO2- and *COOH) were captured by in-situ Fourier transform infrared spectroscopy (FTIR), suggesting a fluent catalytic pathway on the SnS2/SnO2 platform. This work provides a new scheme to build advanced catalysts based on multiscale design and rational phase assembling.