Morphology Regulation And Photocatalytic And Electrochemical Properties Of Iron Oxide Composites

?-Fe₂O₃(Hematite),n-type semiconductor nanomaterials,has a band gap of 2.0-2.2e V and an absorption wavelength of 600 nm,which can effectively absorb visible light.It has the characteristics of excellent chemical stability,low cost,and magnetic usage and environment-friendly as well,thus it may be wide applied in the sphere of photocatalysis.However,due to the low carrier mobility and short excited state lifetime of?-Fe₂O₃,the negatron-hole pair is easy to recombine,which limits its photocatalytic performance.In addition,as transiton metal oxides,some unique characteristics of?-Fe₂O₃make it can be used in the field of supercapacitors,such as high theoretical specific capacity(3625 F/g),brilliant thermal stability,reversible Faradic redox reaction and so on.So?-Fe₂O₃can be used as an excellent electrode material.Therefore,?-Fe₂O₃can be used as an excellent electrode material for supercapacitors,which can store and release a large amount of charge and provide high capacitance.However,due to the poor conductivity and stability,the nanoparticles are easy to agglomerate and the internal particles can not participate in the reaction,which leads to the lack of enough surface active centers and the decrease of specific capacity.So?-Fe₂O₃/RT were prepared by compounding?-Fe₂O₃with rutile TiO₂.The heterojunction between?-Fe₂O₃and rutile TiO₂reduces the recombination rate of negatron hole pairs,thus it will prolong the period of time of negatron hole pairs and improve the photocatalytic performance.Fe₂O₃particles will be loaded on the network structure shaped by rGO/CNTswhich benefits from the high specific capability of Fe₂O₃.Fe₂O₃particles are attached to the rGO/CNTs network structure,which is not easy to agglomerate and promote the reaction of Fe₂O₃particles as much as possible.In addition,rGO/CNTs has excellent electrical conductivity to make up for the poor conductivity of Fe₂O₃particles which enable rGO/CNTs toachieve high specific capacity characteristics.Therefore,it can't solely increase the electrical conduction of the composites,however additionally improve the chemical science performance and win high specific capability characteristics.The contents of the research in this paper are as follows:(1)Magnetic?-Fe₂O₃/rutile TiO₂self-assembled hollow spheres were fabricated via a facile hydrothermal reaction and template-free method.Based on the experimental result,H₂PO₄^-concentration was found to play a crucial role in controlling the shape of these hollow?-Fe₂O₃/RT nanospheres,and the optimal concentration is 0.025 m M.Due to a heterojunction between?-Fe₂O₃and RT,the electron-hole pair recombination rate was reduced,the?-Fe₂O₃/RT nanospheres have glorious photocatalysis compared to?-Fe₂O₃and RT beneath visible-light irradiation,which can degrade Rhodamine B(Rh B)efficiently and the degradation rate was about 16%(RT),60%(?-Fe₂O₃),and 93%(?-Fe₂O₃/RT)after 100 min.Moreover,?-Fe₂O₃/RT showed paramagnetism and can be recycled to avoid secondary environmental pollution.(2)Fe₂O₃/rGO composites were prepared by microwave hydrothermal method.The experimental method is simple and rapid.The nanocomposites are composed of graphene scaffolds with high electronic conductivity and tiny iron oxide particles connected to each other,thus exposing sufficient redox active sites and providing sufficient contact with electrolytes.Due to these morphological advantages,the rapid and stable surface redox reaction of Fe₂O₃particles is promoted,so that the Fe₂O₃/rGO composites provide 775F/g specific capacitance at 1 A/g,and the electrochemical performance is excellent.(3)Fe₂O₃/rGO/CNTs composites were prepared by microwave hydrothermal method,and Fe₂O₃particles were grown on the surface of rGO/CNTs.On the one hand,the skeleton formed by rGO and CNTs provides a large number of growth sites for Fe₂O₃particles.On the other hand,it accelerates the transport and charge transfer of electrolyte ions,so that the Fe₂O₃/rGO/CNTs composite provides a specific capacitance of 801 F/g at1 A/g,and the capacitance retention is 84.4%after 5000 cycles charge-discharge tests.