Preparation And Photocatalytic Performance Of Titania Nanotubes Loaded With Ag Nanoparticles

Titanium dioxide has been widely used in solar cells,gas sensors and photocatalysis due to its novel properties such as light and electricity.Titanium dioxide(TiO2)nanotubes have larger specific surface area,strong adsorption capacity and good ultraviolet absorbability,which has become a hot topic in the field of nanomaterial synthesis and catalytic application.The master’s thesis systematically studied the synthesis of TiO2 nanotubes and their catalytic oxidation performance,the main work is as follows:TiO2 nanotubes was synthesized by hydrothermal method with inner diameter of about 5 to 6 nm,outer diameter of about 9 to 10 nm,the tube length of 200 to 300 nm.This paper studied the conversion of morphology and crystal structure of titanate nanotubes at different calcination temperature by using XRD and TEM,and discussed the influence of different particle size and crystal phase of the TiO2 powder on the synthesis of TiO2 nanotube morphology and crystal structure.The results showed that the crystal shape and size of titanium dioxide have significant influence on the morphology and crystal form of nanotubes.The rutile crystal and large particle size was conducive to the synthesis of nanotubes.TiO2 nanotubes formed in the hydrothermal stage,as amorphous titanate nanotubes,after calcination increase of crystallinity,transform to rutile and anatase.Nanotubes can maintain stable tubular structure at 400℃.The increase in calcination temperature will result in the conversion of titanium dioxide nanotubes into nanorods of different sizes.In order to improve the photocatalytic oxidation properties of TiO2 nanotubes,Ag nanoparticles were loaded on the nanotubes by low-temperature polyols method,and the composite catalysts were characterized by XPS,XRD,TEM and UV-Vis.The results showed that the Ag nanoparticles were uniformly loaded on the surface of TiO2 nanotubes,and the particle size was 8-10nm.The Ag particles do not change the crystal form and morphology of the nanotubes.The modified catalyst prolongs the light absorption to the visible light absorption range.The effect of TiO2 nanotubes composite photocatalysts on the photocatalytic activity of formaldehyde was investigated.The results showed that under the same conditions,the photocatalytic properties of modified TiO2 were improved.The nanotubes loaded with Ag had the highest catalytic efficiency,followed by TiO2 nanotubes.In catalyst addition of low concentration,formaldehyde degradation rate rises as the catalyst concentration rises.When the concentration of catalyst reaches a certain concentration,the degradation rate of formaldehyde will decrease with the increase of catalyst concentration.Meanwhile,it was found that the degradation rate of formaldehyde with formaldehyde decreases with the increase of initial concentration,The higher intensity of ultraviolet light,the better degradation rate of formaldehyde and the increase of dissolved oxygen,which is in favor of increasing the photocatalytic efficiency of formaldehyde.In addition,pH has a great effect on the degradation of formaldehyde,which is beneficial to the degradation of formaldehyde under alkaline conditions.TiO2 nanotubes and Ag/TiO2 nanotubes were added into the tobacco of reconstituted tobacco leaves to investigate the effect of the added catalyst on the pyrolysis of the reconstituted tobacco leaves.The simulated flue gas experiments were conducted to compare the effects of adding catalysts on volatile carbonyls Changes in the amount of release.The results showed that the addition of catalyst significantly changed the pyrolysis process of tobacco leaves while significantly reducing the content of volatile carbonyls.