Study On Preparation And Activity Of Semiconductor Nanocomposite Photocatalyst

Photocatalytic technology is considered to be one of the most promising technologies for mankind to solve environmental problems and energy crises in the 21st century.Through photocatalysis technology,humans can use solar energy to split water to produce hydrogen,which realizes the conversion from solar energy to chemical energy,It is possible to degrade organic pollutants in nature through photocatalysis.This new technology is of great significance for the rational development and utilization of new energy sources,and is of great significance for solving human energy crisis and environmental pollution in the future.The key factor affecting photocatalytic technology is photocatalyst,An excellent photocatalyst should have a wider spectral absorption range and a lower recombination rate of electron-hole pairs.Therefore,it is imperative to develop a photocatalyst with low electron-hole pair recombination rate,larger spectral response range,high efficiency and low cost,and environmental protection and pollution-free.This thesis focuses on the construction of high-efficiency semiconductor-based/Cu₅FeS₄/RGO nano-composite photocatalysts,aiming to design and prepare a series of high-efficiency nano-composite photocatalysts.And through a series of analysis methods such as X-ray diffraction（XRD）,transmission electron microscopy（TEM）,photocatalytic degradation of methyl orange（MO）reaction or photocatalytic deco mposition of water to produce hydrogen reaction to test its photocatalytic performa nce,and explore the analysis The relationship between the semiconductor-based nan ocomposite photocatalyst and the photocatalytic activity is discussed.This thesis ma inly consists of the following two parts:（1）Using urea as a precursor,graphite phase carbon nitride（g-C₃N₄）was synthesized and used as a matrix,using Hummer-s method to prepare oxidized graphene（GO）,A simple method was used to make g-C₃N₄,Cu₅FeS₄and RGO form a compact three-dimensional heterostructure,and a series of g-C₃N₄/Cu₅FeS₄/RGO nanocomposite photocatalysts were successfully prepared.Among them,Cu₅FeS₄and RGO are used as co-catalysts.At the same time,RGO promotes the transport and transfer of electrons among g-C₃N₄and Cu₅FeS₄,and inhibits the recombination of electron-hole pairs.The research results show that the prepared nanocomposite photocatalyst exhibits excellent visible light photocatalytic activity,Compared with pure g-C₃N₄and Cu₅FeS₄,the degradation efficiency of its photocatalytic degradation of methyl orange（MO）is increased by 1.47 times and 45.5 times,respectively,and the stability of the prepared nanocomposite photocatalyst was verified by the photocatalytic degradation cycle experiment.（2）Using cadmium chloride（CdCl₂·2.5H₂O）and thiourea（H₂NCSNH₂）as raw materials,nanorod-shaped cadmium sulfide with unique morphology was synthesized and used as a matrix.Cu₅FeS₄was successfully synthesized by solvothermal method,and Cu₅FeS₄and RGO were loaded by a self-assembly method,and a series of CdS/Cu₅FeS₄/RGO nanocomposite photocatalysts were successfully prepared.Through analysis and test results,it is found that the hydrogen production performance of CdS/0.50wt%Cu₅FeS₄/0.75 wt%RGO is 1.44 times higher than that of pure CdS,which is 726.02times that of pure Cu₅FeS₄,and is CdS/0.50 wt%Cu₅FeS₄binary nanocomposite photocatalyst has 3.18 times the hydrogen production performance.At the same time,the stability of the prepared nanocomposite photocatalyst is verified by the visible light splitting water production hydrogen cycle experiment.Compared with the original materials,the two nanocomposite photocatalysts prepared in this paper have greatly improved photocatalytic activity.This provides important insights for the future design of low-cost and high-efficiency nanocomposite photocatalysts,and will be useful for future photocatalysis.The vigorous development of technology provides a new possibility.