Preparation And Application Of In₂S₃-based Broad Band Photocatalytic Nanocomposites

Photocatalysis as an economical, efficient and environmentally friendly "green" technique offers great potential for photocatalytic oxidation of organic pollutants. Development to capture wide spectrum of solar light and easy recycle are two key for realizing efficient photocatalytic degradation and industrialized application.Indium sulfide (In2S3) with a narrow band gap have a defect spinal structure and lots of vancancies and defects, which not only can absorb NIR light also help to capture photo-generated electrons in order to promote the separation of electrons and holes, so In2S3 is regarded as a good candidate for broad band photocatalyst. We combined with the methords of chemical precipitation and hydrothermal to synthesis In2S3 nanoparticles, CDs/In2S3 composite, In2S3/diatomite composite and In2S3-based photozatalytic paper. Besides, we also study various photocatalytic materials under UV, visible and NIR radiation photocatalytic activity. We also study its photocatalytic mechanism and the photocatalytic stability.The as-synthesized In2S3 nanoparticles have irregular morphology and possess a primary particle size of 5-30nm with high photo-degradation abilities under UV (96.2% within 30 min), visible light (95.4% within 3 h) and near-infrared light (67.2% within 3 h), a phenomenon extremely rare in character with respect to a broad class of photo catalysts that have a single crystalline phase. Due to the up-conversion of carbon quantum dots, we synthesized CDs/In2S3 composites in order to improve photocatalytic ability under NIR irradiation.In2S3 nanoparticles exhibit high photocatalytic activity, but the suspended nanoparticles are easily lost in photocatalytic reaction and separation, which is unfavorable for the recycling of catalysts and may pollute the treated water again. In our work, diatomite was chosed to disperse In2S3 nanoparticles due to its high porosity and large surface area. It proves that the optimum In2S3 and diatomite ratio for synthesis of In2S3/diatomite composites is 1:7, and its high photo-degradation rate is 98.9% (under UV within 30 min),89.6% (visible light within 3 h) and 83.6% (near-infrared light within 3 h). Besides, the as-prepared 1:7 In2S3/diatomite can perform as a stable photocatalyst.In2S3-based photocatalytic paper was prepared with a papermaking technique. And we found that it can decolorize MO aqueous solution. Besides,1:7 In2S3/diatomite-based photocatalytic paper have better photocatalytic ability. After 3 h UV-light irradiation,75.1% of MO was photodegraded by 1:7 In2S3/diatomite, whereas only 73.4% by In2S3.