Highly efficient photocatalytic degradation of different hazardous contaminants by CaIn2S4-Ti3C2Tx Schottky heterojunction: An experimental and mechanism study

The low charge transfer efficiency of isolated semiconductors is an urgent challenge in the photocatalytic degradation of hazardous contaminants. In this work, CaIn2S4/MXene Ti3C2Tx Schottky heterojunctions are synthesized via a simple hydrothermal method and applied for tetracycline hydrochloride degradation and Cr(VI) reduction. Results show that Ti3C2Tx as a cocatalyst can limit the charge recombination and boost the absorption of visible light, thus promoting the photocatalytic efficiency of pure CaIn2S4. An optimized CaIn2S4-Ti3C2Tx hybrid has the highest catalytic rate in the degradation of tetracycline hydrochloride (96%) and reduction of Cr (VI) (98%). Studies probing the mechanism indicate that the photogenerated superoxide radicals and holes play a key role in the tetracycline hydrochloride degradation process, while electrons are core to the Cr(VI) reduction reaction. Besides the high photocatalytic efficiency, the CaIn2S4-Ti3C2Tx hybrids also exhibit outstanding photostability in the present conditions, suggesting the potential for practical use.