Fabrication Of SrTiO₃/M（M=α-Fe₂O₃,Ag） Heterojunction By Interface Redox-induced Synthetic Strategy And Its Application

Heterojunction is the nanocomposite formed by different components of materials.The synergistic interaction of different components in heterojunctions induces interfacial phenomena and novel functionalities.The synergistic interaction between chemically distinct components empowered heteronanocrystals with fascinating interfacial phenomena and great application potential in areas such as superconduction,catalysis,electronics,storage,lithium cells,and biomedicine.Nonetheless,effective technologies to design and fabricate heterojunctions with materials on demand are still lack a common strategy.We propose an interface redox-induced method（IRIS method）based on the revelation of natural patina,dark hair of silverware,dense oxide layer of magnesium and aluminum,which is a general method to prepare heterojunction at normal temperature and pressure.This method is applicable to metals,semiconductors and dielectric materials.IRIS method is universal and can prepare all kinds of heterogeneous materials.IRIS method also has the designability of molecular engineering,which can design and synthesize expected heterogeneous structural materials.The interfacial interaction of heterojunction prepared by IRIS method is strong and has high stability,which can greatly improve the cycle life and efficiency of catalyst in the catalytic reaction.This thesis describes the principle of IRIS method in detail,and verifies the rationality and feasibility of the method by synthesizing SrTiO₃/α-Fe₂O₃ heterojunction and SrTiO₃/Ag heterojunction.Then,the application of photocatalytic hydrogen production,photocatalytic degradation of organic pollutants tetracycline（TC）,methylene blue（MB）and malachite green（MG）were studied.The research of this thesis is as follows:1.The synthesis principle of heterojunction prepared by IRIS method is explained in detail,and the rationality and feasibility of this method are verified by experiments.2.The SrTiO₃/α-Fe₂O₃ heterojunction was prepared by IRIS method and applied to hydrophotolysis.The hydrogen production efficiency of SrTiO₃/α-Fe₂O₃ heterojunction reached10 mmol·g^-1·h^-1,which is much higher than that of pure SrTiO₃.After that,it was applied to photocatalytic degradation of TC and MB.In particular,when TC was degraded,the degradation rate reached 99.06%.Then,the degradation mechanism of TC and MB by SrTiO₃/α-Fe₂O₃heterojunction（IRIS method）photocatalyst was investigated by radical trapping method.3.The SrTiO₃/Ag heterojunction was prepared by IRIS method and applied to the degradation of MG in a multi-channel photocatalytic reaction system（PCX50C Discover）and350 W xenon lamp.The degradation rate reached 99.85%.Then,the mechanism of degradation of MG by SrTiO₃/Ag heterojunction（IRIS method）photocatalyst was investigated by free radical trapping method.