Preparation And Modification Of Indium-based Photocatalysts And Their Photocatalytic Nitrogen Fixation Performance

Recently,semiconductor photocatalytic materials have been widely studied and applied due to their characteristics such as non-pollution,high efficiency and energy saving.However,traditional semiconductor photocatalytic materials possess certain defects in light absorption and separation of photo-generated electron-hole pairs,resulting in poor photocatalytic performance.Therefore,it is particularly important to find efficient catalysts and modify them to improve their photocatalytic performance.Indium-based photocatalysts have been widely studied due to their unique properties,especially indium oxide and indium sulfide materials,which have been applied to the fields of photocatalytic hydrogen production and degradation.In this study,indium-based semiconductor was selected as the host material.In order to improve the photocatalytic performance of the material,it was modified and applied to the photocatalytic nitrogen fixation.The specific research content is as follows:（1）Through hydrothermal method and calcination,the In₂O₃ materials are successfully synthesized,and then they are calcined in different gas atmospheres to produce In₂O₃materials with different concentrations oxygen vacancy defects.Their characteristics were characterized by XRD,DRS,PL and other methods,and their photocatalytic nitrogen fixation performance was studied.The results showthat the In₂O₃ materials calcined under nitrogen display the best nitrogen fixation performance,and its nitrogen fixation efficiency is 58.596μmol·g^-1·h^-1.This experiment proves that manufacturing oxygen vacancy defects can improve the light-capturing and photo-generated carrier transfer capabilities of In₂O₃materials,thereby improving their photocatalytic nitrogen-fixing performance.（2）In₂O₃/In₂S₃ flower spherical heterostructures are synthesized by a two-step hydrothermal method.In₂S₃ flakes are generated in situ and uniformly assembled on In₂O₃microspheres.The morphology,structure,and oxygen vacancies of the materials are systematically characterized.The results have confirmed that the photocatalytic nitrogen fixation performance of material has improved significantly after the formation of the heterojunction.Among them,when the added amount of TAA is 0.05g,the nitrogen fixation efficiency of heterostructure is 40.04μmol·g^-1·h^-1.The nitrogen fixation efficiency of the In₂O₃/In₂S₃ heterostructure is about 4.7 times and 6.0 times higher than that of pure In₂O₃ and In₂S₃,respectively.（3）The photocatalytic performance of the indium sulfide microflower synthesized by hydrothermal method is poor.The In₂S₃/Ti O₂ heterojunction materials are formed by adding P25.After testing the photocatalytic nitrogen fixation performance of the materials,the results show that the best photocatalytic nitrogen fixation performance is 92.98μmol·g^-1·h^-1,which has been greatly improved through the formation of the In₂S₃/Ti O₂ heterojunction,and the optimal addition amount of Ti O₂ is 40%.The study shows that the formation of heterojunction can effectively improve the separation efficiency of photo-generated carriers and then enhance the photocatalytic performance of materials.