Preparation And Properties Research Of Indium-containing Multiple Oxide Semiconductor Photocatalysts

Under the test of the energy crisis and environmental pollution,the emergence of photocatalytic technology undoubtedly provides more choices for this problem.In the field of photocatalysis,the most widely studied and classical photocatalytic materials are Ti O₂and ZnO.Although they have been commercialized and on the market,the shortage that can only work under the irradiation of ultraviolet light limits their use.Especially for utilizing sunlight outdoors.For this reason,the development of new visible light photocatalysts is one of the current research directions.In this paper,indium containing multiple oxides semiconductor materials are studied based on the requirement of new visible light response photocatalytic materials.With the aid of many characterization methods like X-ray powder diffraction,scanning electron microscope?SEM?,transmission electron microscopy?TEM?,Ultraviolet-visible diffuse reflection spectra,X-ray photoelectron spectroscopy and specific surface area test etc.to analyse and research the structure,morphology and photocatalytic performance of indium-containing materials.The main contents are as follows:The first chapter mainly introduces the research background of this paper,including the working mechanism of the photocatalyst,application domain,its development history and research status;Then indium containing multiple oxides semiconductor materials have been introduced,in addition,the synthesis methods of photocatalysts,crystal structure and photocatalytic performance,etc.also have been mentioned;furthermore on the basis of predecessors' research,we put forward the topic selection basis and research content of this paper.The second chapter lists the raw materials,experimental equipments,preparation methods and technologies,a series of characterization methods.The working principles of front instruments also have been briefly introduced.The third chapter,In₂Cu₂O₅ photocatalyst were successfully prepared by citric acid complex method.The synthetic nanoparticles show single phase crystalline property,and the grain size distribution is around 50 nm.The sample's specific surface area is 36.7m²/g indicating that it has high surface activity;According to Ultraviolet-visible diffuse reflection spectrum,the synthetic sample possesses good light absorption ability,the band gap of is about 2.31 eV.Under visible light irradiation,degradation rate of methylene blue solution can be more than 90%within 3 hours,this condition reveals In₂Cu₂O₅semiconductor has a good photocatalytic performance;The hybridization of In-5s/5p and O-2p orbital reduces the bandgap of In₂Cu₂O₅;and internal electric field in[InO₆]octahedral layers accelerates the separation of photogenerated carriers and provides good conditions for photocatalytic reactions.The fourth chapter,through the citric acid complex method,a new kind of indirect-gap photocatalyst In₂Fe₂CuO₇ has been successfully prepared.A seies of characterizations and tests have been carried out by means of X-ray diffraction?XRD?,scanning electron microscopy?SEM?and transmission electron microscopy?TEM?analysis.It is concluded that the sample's phase is hexagonal structure and it consists of well crystallizd ball-like nanoparticles;Combining with structure refinement,we found layered In₂Fe₂CuO₇ material is made up of overlapping[InO₆]octahedral layers and[MO₅]?M=Cu/Fe?polyhedral layers along[001]direction,this unique structure undoubtedly accelerates the speed of separation and migration of photogenerated carriers;Under visible light irradiation,degradation rate of methylene blue solution can be more than 95%within300 minutes;the degradation reaction conforms to the quasi first order kinetic equation and the kinetic constant of the degradation reaction was 0.0311 min^-1.In Chapter 5,Cu InAlO₄ photocatalyst was prepared by citrate complexation method.The structure,morphology,specific surface area and light absorption of the sample were characterized.It was found that CuInAlO₄ is a direct bandgap semiconductor with a band gap of 2.19 eV.The photocatalytic activity of the sample was tested on photocatalytic platform by degrading methylene blue solution.It was found that the degradation rate of the methylene blue solution reached more than 90%within 150 min,and the degradation kinetic constant was 0.0177 min^-1,which was 9 times higher than that of the TiO₂photocatalyst under the same conditions.All of the phenomenons indicate that the CuInAlO₄ has better photocatalytic performance.The mechanism of the photocatalytic activity of the photocatalyst is analyzed in terms of the phase structure and energy band composition;In addition,the active radical capture experiment also provided a basis for explaining the mechanism of photocatalysis;the cyclic experiment also verified that the catalyst has excellent chemical stability,can be reused and is in line with the current concept of green environmental protection.The sixth chapter is the summary of the full text.