Research On Synthesis By Microwave Method And Photocatalytic Activity Of La-doped Titanium Dioxide Nanotubes

The concept of nano-materials was mentioned by the scientific community in the middle of 21st century ,they are the newest materials, and getting more and more in-depth development.Now, nano-materials have shown a good prospect in chemistry,defense,electronics, medicine and other fields,are the most dynamic ones on the new material study,which has an important impact on social,economic development.Nanometer titanium dioxide is a new kind high-efficient degradation photocatalysts which has the innoxious and no-secondary contaminated property, it received much more attention because of the special characteristics of optics, catalysis, and photoelectricity conversion. Due to the high specific surface area, Titanium dioxide nanotubes have wide application prospect in several fields such as solar energy storage performances and utilization, photovoltaic conversion, photochromic and photocatalytic degradation of atmospheric pollutant and water pollutant.This article is under the microwave condition that using hydrothermal synthesis method placed the synthesis of nano-tube system to the Limits of microwave radiation, the synthesis method is a novel synthetic method by the use of microwave dielectric on water.Contrasted to the traditional hydrothermal method, The hydrothermal synthesis method of microwave heating has a fast, responsive, uniform heating system and so on. However, the research reported rarely at home and abroad, and on the rare earth doped titanium dioxide nanotubes preparation and photocatalytic properties were more rarely.In this article, La-doped titanium dioxide nanopowders were fabricated by sol-gel method, and La doped titanium dioxide nanotubes nano-powder prepared by microwave by La-doped titanium dioxide nanopowders as the precursor, at the same time, comparing them about the photocatalytic properties. The samples were observed by field emission scanning electron microscope (SEM), transmission electron microscope (TEM), specific surface area measurement (BET), fluorescence spectrometer (FS) and X-ray diffraction (XRD).The results showed that: As a precursor which prepared by sol-gel method, the titanium dioxide nanopowders'particle size between 40~60nm.Doped nano-powder particles have a more irregular shape, resulting in the increased surface area. Using the nanotitanium dioxide powder as precursor,we can produce relatively complete morphology of titanium dioxide nanotubes by the microwave method,La-doped titanium dioxide nanotubes'external diameter were about 8 ~ 20nm,inner diameter about 6 ~ 18nm,length about 50 ~ 100nm. The titanium dioxide nanotubes in electron microscopy were very complete without HCl pickling, On the contrary, the titanium dioxide nanotubes in electron microscopy showed the local destruction .Formation of titanium dioxide nanotubes can be explained by the combined effect of the microwave and NaOH, the nanopowders dissociated nano titanium dioxide thin firstly, and then titanium dioxide nanotubes formed by the coiled nano-sheets.The photocatalytic properties of nanotubes and nanopowders were researched by degrading the methyl orange solution. At the irradiation of 15W ultraviolet light source, after 150mins, the results of photodegradation showed that the photocatalytic properties of titanium dioxide nanotubes are better than those of nanopowders. The most appropriate doping ratio of La for La-doped titanium dioxide nanotubes in this experiment condition is 0.5%, the degradation rate is 55.28%.This research provides a new kind of approach to improve the photocatalysis property of titanium dioxide and made the application of nano titanium dioxide to become extensive and substantive in many fields.