Z-scheme heterojunction of SnS2-decorated 3DOM-SrTiO3 for selectively photocatalytic CO2 reduction into CH4

The rapid recombination of photoinduced electron-hole pairs as well as the deficiency of high-energy carriers restricted the redox ability and products selectivity. Herein, the heterojunction of SnS2-decorated three-dimensional ordered macropores (3DOM)-SrTiO3 catalysts were in-situ constructed to provide transmit channel for high-energy electron transmission. The suitable band edges of SnS2 and SrTiO3 contribute to the Z-scheme transfer of photogenerated carrier. The 3DOM structure of SrTiO3-based catalyst possesses the slow light effect for enhancing light adsorption efficiency, and the surface alkalis strontium is benefit to the boosting adsorption for CO2. The in-situ introduced SnS2 decorated on the macroporous wall surface of 3DOM-SrTiO3 altered the primary product from CO to CH4. The Z-scheme electron transfer from SnS2 combining with the holes in SrTiO3 occurred under full spectrum photoexcitation, which improved the excitation and utilization of photogenerated electrons for CO2 multi-electrons reduction. As a result, (SnS2)(3)/3DOM-SrTiO3 catalyst exhibits higher activity for photocatalytic CO2 reduction to CH4 compared with single SnS2 or 3DOM-SrTiO3, i.e., its yield and selectivity of CH4 are 12.5 mmol g(-1) h(-1) and 74.9%, respectively. The present work proposed the theoretical foundation of Z-scheme heterojunction construction for enhancing photocatalytic activity and selectivity for CO2 conversion. (C) 2020 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.