Inversed Fabrication And Photocatalytic Performance Of Gold/metal Oxide Semiconductor Nanocomposites

TiO2 is a traditional UV-light photocatalyst and the photoresponse could be improved via doping with non-metal element to make a better use of solar energy.In this dissertation.ultrafine N-doped TiO2 nanoparticles were prepared by solvothermal method.The morphologies.structures,element compositions and hydrogen evolution from photocatalytic water splitting properties have been investigated.On the other hand,coupling with noble metal element was also an important strategy to improve the photocatalytic activity of metal oxide semiconductors.In this dissertation.uniform Au nanoparticle was firstly prepared via seed-mediated method as supporter with various metal oxide semiconductors loaded onto it.The photocatalytic performance was also investigated.The main contents are as follows:1.Synthesis of ultrafine N-doped TiO2 nanoparticles and its performance in hydrogen evolution from water splitting under simulated solar light irradiationUltrafine N-doped TiO2 nanoparticles were prepared through solvothermal method by using TiCl4 as Ti sorce,PVP as dopant and stabilizer.ethylene glycol as solvent.The N-doped TiO2 nanoparticles exhibited the best photoactivity in hydrogen evolution from water splitting when the mass ratio of PVP:TiC4 was about 1:9.which was 4.5 times compared to that of pure TiO2.This was mainly attributed to the doping of element N,the increased surface area and the abundant hydrophilic groups on the surface.2.Inversed fabrication of Au/TiO2 nanocomposites and its properties in hydrogen evolution from water splitting under visible light irradiationThe uniform Au nanoparticles were first prepared by seed-mediated method and further used as supporter to fabricated inversed Au/TiO2 nanocomposites in TiCl4-ethylene glycol system.The Au/TiO2 nanocomposites showed good properties in visible light photocatalytic hydrogen evolution from water splitting.The 2%Au/TiO2 nanocomposites exhibited the best performance with hydrogen evolution rate of 1000 ?mol·h-1·g-1.The surface plasmonic resonance effect of Au,dispersed active site for hydrogen generation and optimal amount of Au contributes to the good photoactivity.3.Inversed fabrication of Au/ZnO nanocomposites and its properties in visible light photocatalysisThe in,versed Au/ZnO nanocomposites were fabricated via sol-gel route in ZnAc2-KOH system with Au nanoparticles as supporter.The obtained Au/ZnO nanocomposites showed good performances in photocatalytic degradation of MO aqueous and photocatalytic oxidation of methanol under visible light irradiation.The inversed nanostructure contributed to the charge separation induced by surface plasmonic resonance effect and prolonged the lifetime of photo-generated charges,then leading to the improved photoactivity.4.Inversed fabrication of Au/CeO2 nanocomposites and its properties in visible light photocatalysisThe inversed Au/CeO2 nanocomposites were obtained with Au as supporter via hydrothermal method in cerium(?)nitrate hexahydrate-hexamethylenetetramine system,and the photocatalytic oxygen evolution from water splitting and photocatalytic degradation of MO aqueous under visible light irradiation were performed in investigated their properties.The 2%Au/CeO2 samples showed the best performance.The surface plasmonic resonance was considered to be the key factor which contributed to the separation of photo-excited electron-hole pairs,and further improved the photoactivity.5.Inversed fabrication of Au/SnO2 nanocomposites and its properties in visible light photocatalysisThe inversed Au/SnO2 nanocomposites were prepared in SnCl4-hydrazine hydrate system with Au as supporter.The photocatalytic degradation of MO aqueous was performed to investigate the photocatalytic activity.The trapping experiment showed the ·O2-and holes(h+)should be the two main active species of Au/SnO2 in MO aqueous solution under visible light irradiation and both of them play important roles for MO photodegradation process.