TiO2/CdIn2S4 S-scheme heterojunction photocatalyst promotes photocatalytic hydrogen evolution coupled vanillyl alcohol oxidation

Abstract

In this paper, a dual-function TiO₂/CdIn₂S₄ S-scheme heterojunction photocatalyst was fabricated through electrospinning and hydrothermal methods for hydrogen generation coupled with the selective oxidation of vanillyl alcohol (VAL) to vanillin (VN). The results indicate that the hybrid material containing 0.5 wt% CdIn₂S₄ possesses the best photocatalytic performance. The hydrogen generation rate reaches 403.36 μmol g⁻¹ h⁻¹. Meanwhile, the conversion of VAL is measured to be 90.99 %. The results of experiments and density functional theory (DFT) calculations elucidate that the S-scheme heterojunction enhances the rate of charge migration and improves the efficiency of charge separation. In this system, the photoexcited holes with stronger oxidation capacity are reserved to catalyze the conversion of VAL into VN, while the photoexcited electrons with stronger reduction capacity are utilized to generate hydrogen. This study introduces a promising strategy that combines photocatalytic hydrogen generation with the selective conversion of organic compounds, offering novel insights into the development of innovative photocatalysts for effective solar energy utilization.