The Preparation Of Al₂O₃ And CdSe Modified TiO₂ Nanowire Arrays And The Study Of Their Photocatalytic Performance

Nowadays,energy and environmental issues become increasingly prominent and it is urgent to develop new energy.Hydrogen is considered as an ideal energy for the sustainable development of human society,and getting hydrogen by photocatalytic water splitting is a perfect solution.However,photocatalytic water splitting is inefficient due to the limited solar light response and the low photo-generated charge separation efficiency of photocatalysts.How to improve the efficiency of photocatalytic water splitting is a hot current scientific research.In order to enhance the light response and the photo-generated charge separation efficiency of photocatalysts,Al₂O₃/TiO₂ and CdSe/Al₂O₃/TiO₂ nanowire arrays were prepared in this thesis.Based on a variety of characterization and performance evaluation,the relationship between structure and performance of the catalyst was studied systematically.The main results was summarized as follows:?1?The TiO₂ nanowires arrays were prepared on a carbon cloth substrate by hydrothermal method.The Al₂O₃/TiO₂ nanowire arrays were obtained after deposited Al₂O₃ layer by Atomic Layer Deposition?ALD?.The Al₂O₃/TiO₂ with 2 Al₂O₃ layer presents the optimal H2 production rate,which is 5.6 times higher than that of pure TiO₂ nanowires.The enhanced photoelectrochemical?PEC?water splitting performance of Al₂O₃/TiO₂ can be attributed to the following reason: the Al₂O₃ layer can effectively reduce surface charge recombination of TiO₂ by chemical passivation effect and field-effect passivation.?2?CdSe nanoparticles were prepared by chemical precipitation process.TiO₂,Al₂O₃/TiO₂,CdSe/TiO₂,CdSe/Al₂O₃/TiO₂,Al₂O₃/CdSe/TiO₂ samples were obtained by changing the positional relationship between the catalyst.The CdSe/Al₂O₃/TiO₂ presents the optimal PEC performance,the photocurrent is 0.088 mA/cm2 under visible light???420 nm?irradiation and the H2 production rate is 4.0 ?mol/?h·cm2?under visible light???420 nm?irradiation with a 0.2 V bias.The enhanced PEC performance of CdSe/Al₂O₃/TiO₂ can be attributed to the following reason: the special assembly of CdSe,Al₂O₃,TiO₂ can reduce charge recombination between CdSe and TiO₂ interface,thus the performance of photoelectrochemical water splitting is enhanced.