Ti~(3+)自掺杂的纳米TiO_2的制备及其可见光催化性能

以TiH2为Ti源,H2O2为氧化剂,首先通过表面氧化得到不同状态的前驱体凝胶,然后采用后续水热处理制备Ti3+自掺杂的纳米Ti O2.考察了前驱体凝胶状态及水热处理时间对材料结构和性能的影响.利用X射线衍射、透射电子显微镜、X射线光电子能谱、电子顺磁共振波谱和紫外-可见漫反射光谱手段对样品进行表征.以次甲基蓝溶液为模拟废水评价样品的可见光催化降解性能.结果表明,与纯Ti O2相比,Ti3+的自掺杂使材料在可见光区有明显的吸收,并具有良好的可见光催化降解性能和循环使用性能.当采用黄色凝胶为前驱体时,在160°C下水热处理24 h所得样品在可见光下光催化降解次甲基蓝的反应速率常数(0.0439 min-1)是纯Ti O2的18.3倍.

Preparation of Ti3+self-doped TiO2 nanoparticles and their visible light photocatalytic activity

Ti3+self‐doped TiO2 nanoparticles were synthesized by hydrothermal treatment of a gel precursor obtained using TiH2 as the Ti source and H2O2 as oxidant. The effects of different states of gel and hydrothermal treatment time on the properties of the samples were studied. The structure, crystal‐linity, morphology, and optical properties of the nanoparticles were characterized by X‐ray diffrac‐tion, transmission electron microscopy, high‐resolution transmission electron microcopy, and UV‐visible diffuse reflectance spectroscopy. The chemical states of Ti and O were confirmed by X‐ray photoelectron spectroscopy and electron spin resonance spectroscopy. Methylene blue (MB) solutions were used as simulated wastewater to evaluate the visible‐light photocatalytic activity of the samples. The samples exhibited strong absorption in the visible light region compared with pure TiO2 and an excellent performance in the photocatalytic degradation of MB. When yellow gel was used as the precursor, the sample obtained after hydrothermal treatment at 160 °C for 24 h exhib‐ited the best visible light photocatalytic activity with a reaction rate constant of 0.0439 min–1, 18.3 times that of pure TiO2. The samples also showed excellent cyclic stability of the photocatalytic activity.