Fabrication Of Indium Oxide Semiconductor Material And Study On Their Photocatalytic Activities Towards The Photosplitting Of Water

Since the modernization of social industrial development,due to the excessive exploitation and abusing of fossil energy,the energy crisis and environmental pollution caused by it are increasingly serious.Researchers all over the world are vigorously developing and using efficient and renewable clean energy.The solar energy attracts researchers to study and utilize it because of its inexhaustible.The conversion of solar energy into chemical energy is currently considered to be an effective strategy for its utilization.Thus,the photolysis of water to hydrogen technology based on sunlight as the driving force is considered by researchers,all over world,as one of the ideal ways to solve the above problems.Among many semiconductor materials,indium oxide（In₂O₃）,as a kind of semiconductor material with low toxicity,suitable band gap and stable thermochemical properties,has been explored by more and more scholars in gas sensors.However,in the field of photocatalysis,there are relatively few studies on it,which is due to its small specific surface area and rapid recombination of photocarriers.Therefore,it is of great significance to develop effective strategies to improve the photocatalytic performance of In₂O₃ semiconductor photocatalyst under visible light.The purpose of this paper is to develop a simple method to synthesize high catalytic activity In₂O₃ semiconductor materials with self-assembly structure,to explore the effect of three-dimensional self-assembly structure on the hydrogen production activity of In₂O₃ catalyst,and to improve the separation rate of photoexcited electron-hole by doping carbon and building heterojunction.The structure,morphology,thickness,specific surface area and energy band position of them were systematically tested by various technical means.Then,Pt was used as catalyst and triethanolamine as sacrificial agent to produce hydrogen from water under visible light.The photocatalytic activity and stability of aquatic hydrogen were investigated by photocatalytic performance experiments.The main contents of this paper are summarized as follows:（1）The precursor was obtained by hydrothermal method and then calcined to prepare In₂O₃.By adjusting the temperature of hydrothermal precursor,In₂O₃catalysts with different degree of self-assembly can be synthesized.The structure,morphology,specific surface area and band position of the samples were measured by various techniques.Finally,the influence of the self-assembly degree of In₂O₃ on their photocatalytic activity was investigated,and the stability of photocatalytic dehydrogenation of the catalysts was investigated by photostability experiments.（2）C-doped precursor was prepared directly by adding carbon source in hydrothermal process,and C-doped In₂O₃ nanorods were obtained by calcination.A series of In₂O₃ nanorods with different doping degree can be synthesized by different heat treatment of carbon inside the precursor.They are calcined in full contact with air in muffle furnace,in incomplete contact with air in muffle furnace and under the protection of inert gas in tube furnace.The structure,morphology,specific surface area and photoelectrochemical properties of the samples were measured by various techniques.Finally,the influence of C doping on their photocatalytic activity was investigated,and the stability of photolysis hydrogen production of the nanorods was investigated by cyclic experiments.（3）A simple in-situ growth strategy was used to construct a solid-phase g-C₃N₄/In₂O₃ composite heterojunction photocatalysis system.Meanwhile,using in-situ growth strategy and new self-made crucible equipment to complete this work.The crystal structure and micro morphology of the heterojunction photocatalyst were characterized by a variety of physical and chemical methods.The effect of different g-C₃N₄ nanoparticles loading on the hydrogen production performance of the composite photocatalyst was discussed.Finally,the photocatalysis mechanism of the heterojunction was studied,and the stability of photolysis was evaluated by cyclic experiments.