Preparation And Photocatalytic Properties Of CdS Nanocomposite Materials

Photocatalytic decomposition and degradation of organic toxic pollutants have good application prospects.Cadmium sulfide（CdS）as a kind of semiconductor catalysts,which have lower forbidden band width（2.4 eV）,can absorb visible light,the characteristics of high catalytic activity.But CdS with corrosive limit its wide application in production and living.This paper studies the problems existing in the application of CdS catalyst that improves its response to visible light and photocatalytic efficiency by preparing CdS composite materials.With transmission electron microscopy（TEM）,scanning electron microscope（SEM）,X-ray diffraction（XRD）,X-ray photoelectron spectroscopy（XPS）,fluorescence spectrum analyzer（PL）,and other technology for the composite material structure,morphology and optical and visible light had been used to characterize the catalytic properties.The main research contents and results are as follows:（1）CdS nanoparticles were successfully prepared by PVP dispersion.The XRD pattern confirmed that CdS were cubic crystalline phase structure,and TEM determined the quantum dot size of CdS with particle size of 4-5 nm.CdS can photocatalyze the degradation of organic dyes in visible light.TiO₂ nanotubes（TNTs）were synthesized from TiO₂ nanoparticles and formed hollow tubes with a diameter of about 10 nm and a length of more than 100 nm.TNTs has a large specific surface area and is responsive to ultraviolet light,and only has adsorption under visible light irradiation.The CdMoO₄ micron hollow sphere was synthesized by chemical precipitation method.The diameter of the sphere was less than 1.CdMoO₄ and TiO₂ have no catalytic performance in visible light,but their adsorption performance is better than that of TiO₂ nanotubes.（2）CdS@TNTs were successfully prepared by chemical deposition.XRD test showed that CdS and TiO₂ nanotubes（TNTs）were successfully prepared,and TEM and HRTEM images confirmed that CdS QDs were successfully attached to the surface of TNTs.The effect of photocatalytic degradation of malachite green（MG）by nano-composite was evaluated under simulated visible light irradiation.The photocatalytic properties of TNTs modified by different concentrations of CdS quantum dots were studied,and their properties ranged from high to low:10%CdS@TNTs,5%CdS@TNTs,15%CdS@TNTs,CdS and pure phase TNTs.The photocatalytic activity of 10%CdS@TNTs was better than that of other nano-composite materials.（3）CdS/CdMoO₄ hollow microsphere composites were prepared by chemical precipitation method.The diameter of the hollow microsphere was about 1m,showing excellent adsorption performance.The good photogenic electron transfer performance of CdMoO₄ makes the CdS/CdMoO₄ hollow microsphere composite possess high catalytic performance and optical stability.The degradation rate of methylene blue light was 98.7%within 60 min,and the repeatability of three photocatalytic experiments was good.