Fu Hongbo, Zhang Shicheng, Xu Tongguang, Zhu Yongfa, Chen Jianmin
Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, People's Republic of China.
Environ Sci Technol. 2008 Mar 15;42(6):2085-91. doi: 10.1021/es702495w.
Fluorinated Bi2WOs catalyst was synthesized by a simple hydrothermal process. The effects of fluorine doping on crystal structure, optical property, photoinduced hydrophilicity, surface acidity, and photocatalytic activity of the as-prepared sample were observed in detail. Fluorinated Bi2WOs presented the enhanced photoactivity for the RhB degradation under the simulative sunlight (lamda > 290 nm), which could be a synergetic effect of the surface fluorination and the doping of crystal lattice. To get a better handle on the mechanistic details of this photocatalytic system, the photodegradation process of RhB was examined. In the fluorinated Bi2WO6 system, five intermediates, namely, N,N-diethyl-N'-ethylrhodamine, N,N-diethylrohodamine, N-ethyl-N'-ethylrhodamine, N-ethylrhodamine, and rhodamine were thus identified, whereas the first three intermediates could only be identified in the case of the Bi2WO6 system. This result indicated that more RhB molecules were degraded via the deethylation process in the fluorinated Bi2WO6 system. It was proposed that the (F-)-containing function on the catalyst surface could serve as an electron-trapping site and enhance interfacial electron-transfer rates by tightly holding trapped electrons. On the basis of the experimental results, a photocatalytic mechanism was discussed in detail.
通过简单的水热法合成了氟化Bi2WOs催化剂。详细观察了氟掺杂对所制备样品的晶体结构、光学性质、光致亲水性、表面酸度和光催化活性的影响。氟化Bi2WOs在模拟太阳光（波长>290nm）下对罗丹明B（RhB）降解表现出增强的光活性，这可能是表面氟化和晶格掺杂的协同效应。为了更好地掌握该光催化体系的机理细节，研究了RhB的光降解过程。在氟化Bi2WO6体系中，鉴定出了五种中间体，即N,N-二乙基-N'-乙基罗丹明、N,N-二乙基罗丹明、N-乙基-N'-乙基罗丹明、N-乙基罗丹明和罗丹明，而前三种中间体仅在Bi2WO6体系中才能鉴定出来。该结果表明，在氟化Bi2WO6体系中，更多的RhB分子通过脱乙基过程被降解。有人提出，催化剂表面含（F-）的官能团可作为电子俘获位点，并通过紧密捕获电子来提高界面电子转移速率。基于实验结果，详细讨论了光催化机理。
