Preparation, Property And Mechanism Of Rare-earth Doped Nano TiO₂

Y3+ and La3+ doped TiO2 powders and films were prepared through ultrasonic-sol-gel method. The primary influence factor of gelling process was investigated and the optimum technological conditions were obtained. The composition, structure and performance of the obtained material were characterized by XRD,SEM,TEM,EDAX,FT-IR and UV-vis. The results showed that the crystalling phase of rare-earth ion doped nanomaterials had the similar structure of anatase, and the particle sizes of these materials were less than 18nm. Rare-earth ions were dispersed uniformly in the crystal lattice of TiO2 in the form of rare-earth oxide (RE2O3). In addition, rare-earth ion doping also resulted in the red shift of the optical absorption edge of TiO2. Based on the experiment and test results and the theoretical analysis, the mechanism of rare-earth ion doping was investigated detailedly. The adsorption performance and mechanism to UO22+ and methyl orange adsorbed by rare-earth ion doped nanomaterials were investigated systematically. The results indicated that Y3+ and La3+ doped TiO2 powders and films exhibited excellent adsorbability, and the adsorption dynamics was in a good accordance with the law of the pseudo-second-order model of Lagergren. The adsorption isotherm fitted the Langmuir equation well. The adsorption mechanism was confirmed to be the combined action of physisorption and chemisorption. Owing to rare-earth ion doping, the compounding probability of electron and cavity was decreased in the crystal lattice of TiO2. Rare-earth ion doped nanomaterials exhibited favorable photocatalysis activity for the degradation of methyl orange under ultraviolet and visible light. The process of photo-catalytic degradation was in line with the law of the pseudo-first-order model of Langmuir-Hinshelwood and Langmuir equation. Y3+ and La3+ doped TiO2 films also possessed favorable photo-induced hydrophilicity under ultraviolet and visible light, which mostly attributed to the coaction of photo-catalytic degradation and the change of film surface structure.