An inorganic-organic hybrid indium tin selenide featuring a two-dimensional layered structure for high efficient photocatalytic Cr (VI) reduction

Photocatalytic reduction technique has been demonstrated as a promising method to treat Cr(VI)-containing wastewater. However, exploring effective photocatalysts with high activity to satisfy the demand from practical application is a challenge. Inorganic-organic hybrid metal chalcogenides should have great potentials as photocatalysts for Cr(VI) reduction due to their rich structural characteristics. Herein, an inorganic-organic hybrid indium tin selenide (Bmmim)8In8Sn8Se30(Se4)2 (BITS), featuring a two-dimensional layered structure, was synthesized through an ionothermal method. Owing to the unique layered structure, BITS can exhibit an outstanding photocatalytic performance for reducing Cr(VI) under visible light irradiation, where its Cr(VI) reduction rate was 26.3, 11.8, and 7.8 times higher than that of P25, In2Se3 nanoparticles, and SnSe2 nanosheets, respectively. Meanwhile, BITS showed a strong anti-interference ability to a variety of anions and cations, and accordingly, maintained its excellent photocatalytic performance in three water bodies, including tap water, lake water, and river water. In addition, BITS can also display a high efficiency for Cr(VI) reduction under sunlight irradiation. Photocatalytic mechanism investigation proved the key role of electrons to the Cr(VI) reduction. Our research results prove the great potential of inorganic-organic hybrid metal chalcogenides as photocatalysts for treating Cr(VI) in wastewater.