具有优异热稳定性的磷修饰氧化钛及其对水中污染物的降解(英文)

Phosphorous-Modified TiO_2 with Excellent Thermal Stability and Its Application to the Degradation of Pollutants in Water

通过水热法制得磷修饰氧化钛,它在亚甲基蓝和对氯苯酚的降解以及消除大肠杆菌的实验中都表现出高于纯氧化钛的优异活性,甚至优于商品化催化剂P25.在捕获剂中降解亚甲基蓝的实验证实羟基自由基是最主要的活性氧物种,并且磷修饰氧化钛在光照下拥有较强的产生羟基自由基的能力.同时,磷修饰氧化钛具有非常高的热稳定性,直到950oC才会发生从锐钛矿到金红石的相变,这是因为粒子表面的磷酸根阻止了金红石在界面的成核因而抑制了相变发生.磷修饰氧化钛的这种优异性质使得它即使在900oC焙烧后也能有效地降解水中污染物.

The phosphorous-modified TiO2（P-TiO2） was synthesized by a hydrothermal method. The as-prepared P-TiO2 was evaluated for the degradation of methylene blue,the dechlorination of 4-chlorophenol,and the inactivation of Escherichia coli. In all these experiments,P-TiO2 shows superior activity compared with pure TiO2 and even better activity than the commercially available P25 in most cases. By carrying out methylene blue degradation in the presence of different scavengers,OH radicals were found to be the dominant reactive oxidizing species. The excellent performance of P-TiO2 was correlated with its pronounced ability to generate ？OH radicals under illumination. We also found that P-TiO2 is extraordinarily stable against annealing. Its transformation from anatase to rutile does not occur until calcination as high as 950 oC. This phase transformation is retarded since the phosphate species on the surface of the particles acts as a barrier to grain boundary nucleation. This peculiar feature of P-TiO2 gives it reliable performance during water decontamination even after calcination at 900 oC since it retains a 100% anatase phase at this stage.