Bo Jiang,Peng Zhang,Ya Zhang,Ling Wu,Hexing Li,Dieqing Zhang,Guisheng Li
A new hierarchical visible-light-driven photocatalyst Bi2TiO4F2 was synthesized by a solvothermal method for the first time. The photocatalyst was characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), N2 adsorption–desorption (BET), UV-vis diffuse reflectance spectroscopy (DRS). Such hierarchical Bi2TiO4F2 microspheres assembled by nanosheets were fabricated via an Ostwald ripening process in the absence of soft templates (surfactants). The as-prepared samples’ bimodal pore-size distributions in the mesoporous region consisted of smaller intra-aggregated pores with peak pore diameter of ca. 4.6 nm and larger inter-aggregated pores with peak pore diameter of ca. 17.0 nm. The band gap of the obtained Bi2TiO4F2 was estimated to be about 2.71–3.06 eV for various solvothermal treatment time. Owing to the hierarchical structure with bimodal pores, low band gaps and high crystallinity, the Bi2TiO4F2 microspheres exhibited high photocatalytic performance and durability for the degradation of rhodamine B (RhB) under visible light (> 420 nm). It was proved that the photo-generated holes and ˙OH radicals played an essential role for the oxidation of RhB.
Guisheng Li,Bo Jiang,Xin Li,Zichao Lian,Shuning Xiao,Jian Zhu,Dieqing Zhang,Hexing Li
Fullerene (C60)-enhanced Bi2TiO4F2 hierarchical microspheres were prepared by a facile solvothermal method. Compared to the pure Bi2TiO4F2 photocatalyst, the C60/Bi2TiO4F2 samples exhibit much stronger photocatalytic performance for degrading Rhodamine B (RhB) and Eosin Y (EY) under visible light irradiation. Such greatly enhanced photocatalytic activity may be ascribed to strong combination and heterojunctions between C60 and Bi2TiO4F2, favorable for charge separation and light adsorption. Loading C60 on Bi2TiO4F2 results in a new photocatalytic mechanism (based on photo-generated hvb+ and ·O2- radicals) different from that of pure Bi2TiO4F2.
Zhijie Du,Wenzhi Li,Zhiping Xu,Hao Wu,Hasan Jameel,Hou-Min Chang,Long-Long Ma
Effects of a photocatalyst, C60-modified Bi2TiO4F2, on pine kraft lignin under visible light irradiation were investigated, along with those of Bi2TiO4F2 and C60/TiO2 as references. The influences of pH, C60 mass fraction, and the initial lignin concentration on lignin conversion and yields of mono-phenolic products were investigated. Seven products were determined by GC/MS, including phenol, 2-methoxyphenol, 4-ethyl-2-methoxyphenol, 2-methoxy-4-vinylphenol, vanillin, acetovanillone, and homovanillic acid. The yields of products and lignin conversion were higher by C60/Bi2TiO4F2 than Bi2TiO4F2 and C60/TiO2. C60/Bi2TiO4F2 and C60/TiO2 were more stable than Bi2TiO4F2 upon repetitive recycling of catalyst. The effectiveness of C60/Bi2TiO4F2 declines 25%, whereas that of Bi2TiO4F2 declines 56.4% after being recycled five times. FTIR and HRTEM indicated that the deactivation of photocatalysts might be caused by lignin adsorbed on the surface of photocatalysts and the change in the crystal structure.
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