Catalytic Properties Of Semiconductor Complex Photocatalyst In Primary Amine Oxidation Coupling Reaction

Imines are involved in many fields of our life and synthesis of imines is one of the most studied organic synthesis reactions in the field of heterogeneous catalysis.The synthesis of imines by oxidative coupling reaction of primary amine is widely used.Photocatalytic organic synthesis is gradually replacing traditional organic synthesis because of its advantages of green and environmental protection.The presence of photocatalyst is the most important part of the reaction.Therefore,in this paper,three different photocatalysts were successfully used in the oxidation coupling reaction of primary amine by designing three different photocatalysts.The specific work content is as follows:（1）Preparation and performance of type-ⅡZnIn₂S₄/MoS₂ photocatalystIn this paper,ZnIn₂S₄/MoS₂ composite photocatalysts were prepared by combining chemical exfoliation method and hydrothermal method,forming type-II heterojunction,reducing the recombination of photogenerated electron-hole pairs of pure ZnIn₂S₄,thereby promoting the photocatalytic primary amine oxidative coupling progress of the reaction.Among the prepared composites,when the addition amount of MoS₂ is 10%,the catalytic performance is the best,and the yield and selectivity of imine are 94.8%and 97.6%,respectively.Compared with pure ZnIn₂S₄ and MoS₂,the activity is significantly improved.promote.（2）Preparation and properties of Z-schemeα-Fe₂O₃/Cu₂O photocatalyst:In this paper,Z-schemeα-Fe₂O₃/Cu₂O heterojunction composite photocatalysts were prepared by hydrothermal method and precipitation method and applied in the oxidative coupling reaction of primary amines.The formation of the internal electric field in the Z-Scheme heterojunction can effectively be promoted.The transfer and separation of charge carriers increase the oxidation/reduction potential of photocatalysts,broaden the absorption of visible light by semiconductor materials,and make more effective use of sunlight.After adding 11wt%α-Fe₂O₃ to Cu₂O,the yield and selectivity of imine were the highest,reaching 69.3%and 89.7%,which indicated the construction of Z-scheme heterojunction was favorable for the reaction.（3）Preparation and properties of Z-schemeα-Fe₂O₃/g-C₃N₄/GO photocatalysts:In this paper,α-Fe₂O₃/g-C₃N₄/GO ternary material was successfully synthesized by one-step high-temperature calcination method.The doping ofα-Fe₂O₃ and the addition of graphene can build a multi-level electron transport channel together with g-C₃N₄ to improve the catalytic activity.The oxidative coupling reaction of primary amines shows that the composites synthesized in this paper have good photocatalytic performance,and when the addition amount ofα-Fe₂O₃ is 5wt%and the addition amount of GO is 3wt%,the reaction activity is the best,and its yield and selection was 76.9%and 93%,respectively.It also shows that the multilevel electron channel further accelerates the transition and transfer of electrons in the presence of light,which together with the Z-Scheme structure promotes the progress of the reaction.Finally,a series of necessary characterizations were carried out on the prepared photocatalysts to clarify the properties and the possible photocatalytic reaction mechanism.