Photocatalytic Degradation of RhB by Fluorinated Bi₂WO₆ and Distributions of the Intermediate Products

Abstract

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.

Towards efficient photoinduced charge separation in carbon nanodots and TiO2 composites in the visible region

“…S2e, ESI †), which might be due to two concomitant photodegradation processes: cleavage of the conjugated chromophore ring structure and de-ethylation of RhB. 38,39 The intensity ratios of the characteristic absorption peak of RhB (554 nm) after irradiation under visible light for a constant time interval (C) and prior to irradiation (C 0 ) were calculated as shown in Fig. 4a.…”

Heterogeneous photocatalysis on construction materials: effect of catalyst properties on the efficiency for degrading NOx and self cleaning

“…The fact that no clear trends are found for Rhodamine B could be attributed to the fact that degradation of RhB dye follows two competitive processes such as N-deethylation and destruction of conjugated structure (43,44,45). Therefore, for these different catalysts, the degradation mechanisms seem to be dependent on the catalysts.…”

Preparation and Photocatalytical of Bi2WO6-xF2x/ZnWO4 Composite Materials by Hydrothermal Method

“…At the same time, the fluoride Bi 2 WO 6 presented to improve the photocatalytic degradation of RhB, which may be due to surface synergistic effect caused by fluoride and fluorine ions doped into the crystal lattice. According to these results, regardless of the fluorine doping approach, the introduction of fluorine can really improve the photocatalytic activity of semiconductor [6]. Moreover, rather than using a single light catalyst, and other semiconductor optical coupling, metal or molecular catalyst heterostructure formation, these structures have been found to significantly improve the photocatalytic activity [7].…”

“…Fluorine ion may increase ZnWO 4 crystal WO 6 octahedral W atoms in the surrounding coordination layer, and cause WO 6 octahedral deformation [5], leading to increased photoproduction electron transfer rate, more electrons transfer to the photocatalyst surface to improve the ability of photocatalytic degradation of RhB. At the same time, the fluoride Bi 2 WO 6 presented to improve the photocatalytic degradation of RhB, which may be due to surface synergistic effect caused by fluoride and fluorine ions doped into the crystal lattice.…”