Ti3C2/In4SnS8肖特基异质结用于高效光催化生成H2O2和Cr(Ⅵ)还原OA北大核心CSTPCD

Artificial photosynthesis is an appealing approach for generating hydrogen peroxide(H2O2)from H2O and O2 with solar energy as the sole energy input.However,the current catalyst systems commonly face challenges such as the limited optical absorption,poor electron-hole pair separation efficiency,and restricted surface reactivity,which hinders the overall photoactivity.Here,we immobilize cubic-phase ultrathin In4SnS8 nanosheets(Eg=2.16 eV)with thickness of 5-10 nm on the surface of few-layer Ti3C2 to develop a sandwich-like hierarchical structure of Ti3C2/In4SnS8 nanohybrid via in situ hydrothermal strategy.The enlarged interfacial area and close contact between Ti3C2 and In4SnS8 benefit for carrier transportation among nanohybrids.Characterization through X-ray diffraction(XRD),transmission electron microscopy(TEM),and X-ray photoelectron spectroscopy(XPS)corroborates the successful construction of Ti3C2/In4SnS8 nanostructures.Band structures investigation including valence band maximum and Mott-Schottky plots reveals the formation of Schottky junction in this 2D/2D heterostructure,that favors for ultrafast charge carrier separation and transportation from In4SnS8 to Ti3C2 and preventing the electrons backflow from Ti3C2 to In4SnS8.Photoluminescene analysis and photo/electrochemical measurements prove that the combination of Ti3C2 and In4SnS8 accelerates the transportation of photoexcited electron-hole pairs and efficiently suppresses charge carrier recombination.Unsurprisingly,7 wt%Ti3C2/In4SnS8 catalysts exhibit the highest visible-light-driven photoreactivity with H2O2 production rates of 1.998 µmol·L-1·min-1 that is 2.2 times larger than that of single In4SnS8.Additionally,Ti3C2/In4SnS8 demonstrates a multifunctional capability in Cr(Ⅵ)reduction with the greatest reaction rates of 19.8×10-3 min-1 that is almost 4-fold larger than that of individual semiconductor.Moreover,the nanohybrids exhibit excellent photostability after 5 cycles testing in both reaction systems.The morphology,crystal structure and composition for Ti3C2/In4SnS8 remain unaltered after photoreaction.A comprehensive analysis including trapping agents and atmosphere experiments as well as electron paramagnetic resonance demonstrates that the H2O2 evolution pathway consists of two channels:a two-step successive 1e-oxygen reduction reaction and a one-step 2e-water oxidation reaction.This work may provide a viable protocol for designing efficient and multifunctional photocatalytic systems for solar-to-chemical energy conversion.