Study On The Preparation And Propreties Of Multi-walled Carbon Nanotubes/TiO₂ Composite Film

TiO₂ films were cheap, non-toxic, stable, easily to use and had the advantages of recycling. It had a very wide range of application in the field of environmental pollution control and photoelectric conversion. At present, TiO₂ films have entered a practical stage, but there are still many technical problems of low photocatalytic activity and low utilization of sunlight and TiO₂ films photoelectric conversion technology is still in the experimental stage. In recent years, technology of TiO₂ films has a rapid development, including precious metals deposition, transition metal ion doping, the non-metallic doped photosensitive surface and the methods of compound semiconductor. In this paper, the new material Multi-walled carbon nanotubes (MWNTs)was added to TiO₂ and it was successful to prepare a MWNTS/TiO₂ composite film of stability and good translucent. In this paper, the photoelectric conversion film composite nature and the nature of photocatalytic activity etc were studied.Firstly, TiO₂ nanoparticles colloidal solution was synthesised by sol - gel and while MWNTs was scattered in sodium dodecyl sulfate (SDS) forming aqueous solution in ultrasound uniform suspension. Czochralski method was used in the dipping MWNTs films and TiO₂ films on the conductive glass and slide film and after a series of treatment MWNTs/TiO₂ composite film was maded.Secondly, the nature of photovoltaic conversion of MWNTs/TiO₂ composite film was studied through electrochemical method. It was found that in compared to TiO₂ film, MWNTs/TiO₂ films had a higher voltages, stronger photocurrent. Alkaline electrolyte had a greater impact on the composite film photocurrent. Neutral electrolyte had a greater impact on the films voltage and had a response to visible light. It was told that after the addition of MWNTs, the nature of TiO₂ was optimized.Thirdly, the photocatalytic nature was studied on the composite film of the substrate to slide for the TiO₂ and MWNTs/TiO₂ films. It wad showed that after adding of MWNTs, the photocatalytic effect of film to methyl orange was greately enhanced. Acidic environment, a five-storey composite membrane of pulling speed of 4.4 mm/s and 450℃for the calcination temperature were the most optimum conditions for the MWNTs/TiO₂ films. It was found that the sun light catalytic effect had a relationship of the light intensity when the direct sunlight was used in photocatalysis experiments as a light source. The light intensity is the main influencing factor to the film catalytic effect.Fourthly, through the spectra analysis, the Optimization Mechanism of MWNTs to TiO₂ was preliminarily studied. The results showed that after the adding of MWNTs, it not only had an effect on crystallization conditions and surface morphology, but also had an effect on band structure and defect state of TiO₂. It initial infer that TiO₂ on the surface of MWNTs may combine by Ti-O-C covalent bond to MWNTs.