Plasmon enhanced Sn:In2O3/attapulgite S-scheme heterojunction for efficient photothermal reduction of CO2

Photothermal catalytic conversion of CO2 and H2O to solar fuels has great potential in industry but remains challenge using full solar spectrum. Herein, plasmonic Sn:In2O3/H-ATP(acid modified attapulgite) heterojunction was prepared by coprecipitation coupled with microwave hydrothermal method. The localized surface plasmon resonance (LSPR) effect of In2O3 triggered by doping with Sn2+ broadened the absorption range from visible to mid-infrared light and released high-energy hot electrons by providing heat simultaneously. Results revealed that the Sn:In2O3/H-ATP demonstrated remarkable CO2 photoreduction property with a CO yield rate of 17.9 μmol g−1 h−1 and 84 % selectivity under solar light irradiation. The apparent quantum yields (AQE) achieved 1.7 % at 420 nm. The H-ATP not only immobilized Sn:In2O3 to trap CO2 molecules attributed to its large specific area and adequate active sites, but also acted as a semiconductor to build S-scheme heterostructure with Sn:In2O3, which provided an effective way to capture and transform CO2. In addition, in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) was used to explore the photocatalytic reduction CO2 mechanism. In order to understand the mechanism of photocatalytic reduction, in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) was used. It was found that photothermal synergistic effect facilitated the generation of the key intermediate ·CO2- species which contributed to enhance CO production. This work provides a potential strategy for photothermal CO2 reduction by taking advantage of natural clay and full solar energy.