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Bismuth oxyfluoride/bismuth oxyiodide nanocomposites enhance visible-light-driven photocatalytic activity

Chen, Chiing-Chang, Fu, Jing-Ya, Chang, Jia-Lin, Huang, Shiuh-Tsuen, Yeh, Tsung-Wen, Hung, Jiun-Ting, Huang, Peng-Hao, Liu, Fu-Yu, Chen, Li-Wen
Journal of colloid and interface science 2018 v.532 pp. 375-386
Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, bismuth, energy, energy-dispersive X-ray analysis, gentian violet, hot water treatment, irradiation, light, nanocomposites, pH, photocatalysis, reflectance spectroscopy, scanning electron microscopes, scanning electron microscopy, superoxide anion, temperature, transmission electron microscopy
This is the first paper to report a series of bismuth oxyfluoride/bismuth oxyiodide (BiOₚFq/BiOₓIy) nanocomposites with different F/I molar ratios, pH values, and reaction temperatures that were synthesized through a template-free and controlled hydrothermal method. These nanocomposites were characterized through scanning electron microscope energy dispersive microscopy (SEM-EDS), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier-transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET), and diffuse reflectance spectroscopy (DRS). Under visible-light irradiation, the BiOₚFq/BiOₓIy composites exhibited excellent photocatalytic activities in the degradation of crystal violet (CV) and 2-hydroxybenzoic acid (HBA). The order of rate constants was BiOF/BiOI > BiOI ≫ BiOF. The photocatalytic activity of BiOF/BiOI composites reached a maximum rate constant of 0.2305 h⁻¹, 1.2 times higher than that of BiOI and 100 times higher than that of BiOF. Thus, the derived BiOF/BiOI is crucial for photocatalytic activity enhancement. After the removal of CV in the third cycle, no apparent deficits in photocatalytic activity were observed, and the observed deficit was 8.2% during the fifth run. Overall, the catalytic activity and stability observed for the proposed composites were determined to be adequate under visible-light irradiation. For various scavengers, the noted quenching effects demonstrated that reactive O₂⁻ has a notable role in the degradation of the applied CV.