Preparation And Photocatalytic Properties Of Indium-doped TiO₂ Nanoparticles

Research on the photocatalytic properties of TiO₂ nanoparticles has been the focus of numerous studies and TiO₂ has been a hotpot used as potocatalyst to degrade a great deal of organic pollutants.At present, how to develop high-performance TiO₂ catalyst used for industry and environmental pollution, which is still in constant exploration.This thesis develops the metal doped TiO₂ and metal-nonmetal co-doped TiO₂, and then conducts research into their photocatalytic performances.Firstly, In-doped TiO₂ nanoparticles were synthesized using a controlled sol-gel method with n-butyl titanate as a titanium source, In （NO3）3 · 4.5H2O as ion-doped indium precursor. The average In-doped TiO₂ nanoparticles size is less than 20nm, which presents uniform spherical particles and mesoporous structure characterized by SEM、TEM、BET. In the specific surface area of 2% In-doped TiO₂ nanoparticles reach to122.703 m2/g, which improves 35.26% compared to pure TiO₂ nanoparticles surface area （90.718m2/g）. In3+ has been incorporated in the crystal lattice of TiO₂ nanoparticles, changing electronegativity of Ti and forming a In-O-Ti high binding energy system, which evidenced by XPS, XRD.Secondly, further conduct of the In-N co-doped TiO₂ and In-C co-doped TiO₂ nanoparticles were prepared on the basis of a single In-doped TiO₂. The In-N co-doped composite TiO₂ nanoparticles were modified with melamine as nitrogen ions; The In-C co-doped composite TiO₂ nanoparticles were prepared with glucose as carbon source and P25 as raw materials. The samples were characterized by XPS, XRD and the results show that:N, C ions are uniformly dispersed in the TiO₂ lattice without causing deformation of the crystal lattice of TiO₂. From the UV-Vis on the range of visible light absorption it is concluded that the right amount of In metal ions and nonmetal N, C ions collaborative doping TiO₂ can improve the absorption of visible light conversion capability.Finally, the Methylene Blue （MB） and Reactive Red 4 （RR4） were used to simulate the organic dye pollutant, and then three groups of modified composite catalysts were added to it apart to perform photocatalysis experiments. In this way, the photocatalytic performance and optimum processing technology of each group were explored. The photocatalysis experiments showed that single-doped and co-doped could reduce the band gap of TiO₂ effectively, increase the amount of electron hole pair, and reduce the threshold value of photoelectron hole. Therefore, the catalysts could have more powerful adsorption capacity and photocatalysis capability. The optimum concentration ratio of each group after modified optimization is 2%In-TiO₂,0.7%In/N-TiO₂, and 15%In/C-P25. Moreover, the photocatalytic degradation rate of each group is 90.0%, 90.4%,92.3%.