Studies On The Modification Of Nano-TiO₂Codoped With FE-N And Its Photocatalytic Activity About Degradtion Of Dye Wastewater Under Visble Light

As a photocatalyst which has high catalytic activity, low cost, corrosion resistance, chemical stability and rich resource, nano-TiO2has been widely investigated for its wide potential application. However, the pure TiO2absorbs only the small ultraviolet part(3%-5%) of solar light due to its wide band-gap of3.2ev. Therefore, it has become a crueial issue in the field of TiO2photoeatalysis to make the TiO2responding to the range of visible radiation wavelengths through adoping to improve its use of visble light.In this paper, modified method of metal(Fe) and nonmetal(N) co-doped TiO2photocatalyst is studyed. Through the sol-gel method, co-doped nano-TiO2photocatalysts with different Fe, N ratio are prepared. As compared with other doping methods, this method is lower energy-consuming and easily manipulated, ensuring the uniform dispersal of adorning ion. Factors affecting nano-TiO2crystal composition, particle size and photocatalyitc activity such as the different N, Fe ratio are studyed. Through photocatalytic degradation of methyl orange the process in the laboratory and conditions of preparation of Fe and N co-doped TiO2powder is determined. The XRD、SEM、FT-IR and UV-Vis are used to characterize the titania nano-powder.From the results of XRD、SEM and UV-Vis we can find that change in the amount of iron and nitrogen do not change the crystal morphology of nano-TiO2. It still shows spherical particles and large particles are formed by the agglomeration of many small particles. Meanwhile, the change in the amount of iron and nitrogen also has little effect in catalyst particle size. However, the ability of catalyst to absorb visible light shows a tendency that first increased and then decreased with the increase of the doping amount. Respectively, it achieves the best value in N/Ti of0.5, Fe/Ti of0.5%. And also in the photodegradation experiments, methyl orange as the pollutants, it has the highest removal86%. The result of FT-IR shows that the surface of catalyst has the adsorption of water molecules. There is no corresponding absorption at2920and2858cm-1, it means that the degradation of organic matter have been completed. And also the result that there is no corresponding absorption of Ti-O-C at 1035～1125cm-1shows that the tetrabutyl titanate hydrolyzed completely.Compared with TiO2、N-TiO2and Fe-TiO2, the co-doped TiO2had obviously visible light activity. Within titanium, nitrogen, iron molar ratio of1:0.5:0.005, iron(III) and nitrogen co-doped TiO2calcined at500℃has the highest photocatalytic activity. The best photocatalytic degradation of methyl orange can reach to86%in six hours. And the samples are single anatase, and the particle size is about18nm.