Preparation And Photocatalytic Property Of ZnO Nanorod And Its Modified Film

In the past few years, there has been an increasing interest in ZnO nanowire/nanorods because of their unique properties and applications in electronic devices, gas sensors, antibacterial and antisepsis etc. At the same time, the application of ZnO nanowire/nanorods in the treatment and protection of environmental pollution has been attracted the public concern because semiconductor-assisted photocatalysis can convert the pollutants into harmless substances directly. ZnO is one of the most widely used effective photocatalyst for its high efficiency, non-toxic nature and low cost.In this paper, we developed a new simple, economic, facile method—one step solution growth method for ZnO nanorods. Firstly, zinc acetate was dissolved in alcohol and then lithium hydroxide was added. Secondly, the solution was dried and calcinationed at 350℃for 2h to get ZnO nanorod. Through changing the preparation condition, we obtained large surface-to-volume ratio of ZnO nanorods with solid growth method and evaluated theirs excellent photocatalytic property. Furthermore, ZnO nanorod filmwas modified by TiO₂ to improve the photocatalytic activity and (photo)chemical stability.The effects of main conditions on the formation of ZnO nanorods have been discussed. It was found that the experimental condions for large surface-to-volume ratio of the ZnO nanorods are as follows: the concentration of zinc acetate and lithium hydroxide were 0.2mol/L and 0.14mol/L, a heat-treatment temperature of 350℃.The as-prepared ZnO nanorods have excellent photocatalytic activity for its high surface-to-volume ratio. When the initial concentration of the photocatalyst was 0.1g/L, the photodegradation efficiency of methyl orange was better than P25. In the case of methylene blue, the photodegradation efficiency could be up to 96.73% within 20min while that of P25 was just 44.5%.ZnO nanorods films prepared by two-step chemical methods were further modified by TiO₂ by dipping method. The films absorption and photocatalytic property were studied. From the absorption result, it could be seen that there is a little red shift of the ZnO absoption band edge after modifying. Meanwhile, in the visible light region there is a new absorption peak at 420nm,which is attributed to the coupling of ZnO and TiO₂ and having an ability to absorb photo in visible light. It was found that the photocatalytic activity would be higher with the inceaase of light intensity, but not linear. It was also found that the TiO₂ surface-modification can improve the photocatalytic activity and (photo) chemical stability of the ZnO nanorod film which had an attracting foreground for application.