Study On Preparation And Physical Properties Of Different Structure Titanium Dioxide Nanoparticles

TiO₂ Nanomaterial contain three crystal structure of anatase brookite and rutile.The difference of these three crystal structure induce tremendous diversity on the physic properties, so it induce their especial applied filed.Between them the anatase possess the best photocatalyst activity.It has vast applied foreground in clear the air and water purification; rutile TiO₂ has high temperature resistance, low temperature resistant, corrosion resistant, high strength,small proportion and some other excellent performance,so it is widely used in aviation military,aerospace, navigation, machinery, chemical industry, sea water desalinization and some other aspect; some unique character of the brookite make it has extrem potential applide in the catalyst and dry cells.Invest the structure and properties of TiO₂ nano-semiconductor is the one focus of scientific research,and synthesis of TiO₂ nonoparticles both possess crystal structure and stabilized physic and chemical porperties caused widely attention.First, utilize sol-gel method prepared Ti(OH)4 xerogel powder use butyl titanate mainly,thermeal treatment at different temperature,obtain samples under 200℃,350℃,400℃,450℃.For XRD,TEM,Raman test,it was showde that the sample under roasting temperature at 350℃was total transformed to anaste TiO₂,with the rise of the treatment temperature, diffraction peaks is more edge,it was show that the size of the TiO₂ nanoparticals was increase with the rise of the treatment temperature;under 200℃treatment,the size of the nanoparticals approximately 5nm;under 450℃treatment, the size of the nanoparticals approximately 50nm,they are all spheroid. UV-vis spectroscopy revealed that with the decrease of the nanoparticle size the absorption increase and have the obviously blue shift phenomenon.The amorphous TiO₂ particles'absorption is very weak at ultraviolet region, with the increase of the nanoparticle size ,the absorption remove to high wave and have the obviously red shift phenomenon.Anatase TiO₂ with different particle size has different photodegradation efficiency to rhodamine B dyes,TiO₂ nanoparticle under 350℃treatment has very good photodegradation efficiency to rhodamine B dyes.With increase of the particle size the photodegradation efficiency decrease obviously.Seconed, use hydrochloric acid contain with TiCl3, NaCl saturated solution and little coordination agent urea as precursor, reaction was under hydrothermal condition above 200℃, thus could prepard brookite TiO₂ with uniform partial size .For XRD TEM Raman test indicated that the sample possess single brookite TiO₂ structure ,possess uniform particle size, same grain shape, particle contain perfect internal structure.Accord to the result of the experiment about brookite TiO₂ with different particle size at photodegradation efficiency to rhodamine B dyes,the brookite TiO₂ nanoparticle has little photodegradation efficiency to rhodamine B dyes. Last,in these chapter we utilize sol-gel method synthesis rutile TiO₂ directly at room temperature.Accord to the result of the test of XRD,TEM,Raman.The samples contain single rutile TiO₂ structure. UV-vis spectroscopy revealed that the sample of rutile TiO₂ nanoparticle prepared in this methord absorption band edge is 420nm, corresponding band gap width is 2.95eV. Rutile TiO₂ particle has very good photodegradation efficiency to rhodamine B dyes,far better than rutile TiO₂ particle obtained by thermal treatment,but little lower than P25 TiO₂ particle'photodegradation efficiency to rhodamine B dyes.