| The full use of sunlight is one of the most effective routes to solve the energy crisis and environmental problems now (such as the greenhouse effect, ozone depletion, environmental pollution, etc.). TiO2 is considered to have good application future as photocatalytic materials because of its non-toxicity, high catalytic activity and high resistance to UV light corrosion, acid, alkali and being of strong oxidizing agents, etc. However, the band gap of TiO2 materials is so wide that its absorption efficiency is very weak in the visible spectral range. The research and development of new photocatalyst materials and technology, which is aimed to enhance the absorption in the visible spectral range, has become a hot area in photocatalyst field.In this paper, it is foucused on the preparation, surface modification and photocatalytic effect enhancement of one-dimensional titanate nanobelts, which is a new kind of TiO2-derived photocatalytic material. A novel titanate nanobelts with the diameter of 30-50 nm and length of several micrometers are synthesized by hydrothermal method, and their phase is to be proved to H2Ti5O11·3H2O. The relationship between the different synthesis technology and the growth of the titanate nanobelts have been systematically discussed, such as hot alkali concentration, pH value of the posttreatment process, hydrothermal reaction time and hydrothermal reaction temperature. The products which are smaller size, uniform disperse, smooth surface can be controllable preparation, and the best condition as follows:the concertion of NaOH is 10M, the hydrothermal time is 2 days, the hydrothermal temperture is 180℃and the post-treatment pH value is 5.6. The physical properties of titanate nanobelts also are researched. (1) The titanate nanobelts have good thermal stability, the titanate can contain the fomer phase and morphology when the tempertures are below 400℃,and when the tempertures are beyond the 600℃, the phase of titanate is disappeared. (2) The titanate nanobelts have good photoabsorption performance and catalytic effect under UV-visible light irradition, and the photocatalyst ratio is 67%. But the respond of visible light is very weak and the the photocatalyst ratio is 6%. (3) Electrochemical lithium storage performance shows that the first charge and discharge capacities are 190 and 155mAh/g, respectively. After 20 cycles, the charge and discharge capacity remains 108 and 106mAh/g. It indicates that the material has good charge and discharge reversibility.Noble metals (Pt and Au) nanocrystals is deposited on the surface of one-dimension titanate nanobelts, and then the corresponding heterojunction materials are self-assembly formed by the linkering molecule of thioglycolic acid (TGA). The averegy size of Pt nanoparticle is 2.8nm. After irradion 240min under UV-visible light, the photocatalyst ratio of 11wt%-Pt/titanate nanobelts hetejunction material is 98%,and the photocatalyst ratio is 68.2% under visible light irradition. The size Au nanoparticles are 10-20nm. The catalytic effect of Pt/titanate nanobelts hetejunction material are obvious. When the content is 5%, the photocatalyst ratio is best.,which is 100% under UV-visible lighr irradition 120min and 99.5% under visible light irradition 180 min. |
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