Controlled hydrothermal synthesis of bismuth oxychloride/bismuth oxybromide/bismuth oxyiodide composites exhibiting visible-light photocatalytic degradation of 2-hydroxybenzoic acid and crystal violet

• Published in: Journal of colloid and interface science Vol. 526; pp. 322 - 336
• Main Authors: Siao, Ciao-Wei, Chen, Hung-Lin, Chen, Li-Wen, Chang, Jia-Lin, Yeh, Tsung-Wen, Chen, Chiing-Chang
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15.09.2018
• Subjects: 2-Hydroxybenzoic acid; BiOxCly/BiOmBrn/BiOpIq; bismuth; Composites; Crystal violet; dispersions; electron paramagnetic resonance spectroscopy; gentian violet; hot water treatment; monitoring; Photocatalysis; photoluminescence; photolysis; reflectance spectroscopy; superoxide anion; temperature; transmission electron microscopy; X-radiation; X-ray diffraction; X-ray photoelectron spectroscopy; 2-Hydroxybenzoic acid; Composites; Crystal violet; BiOxCly/BiOmBrn/BiOpIq; Photocatalysis; BiO(x)Cl(y)/BiO(m)Br(n)/BiO(p)I(q)
• ISSN: 0021-9797; 1095-7103; 1095-7103
• DOI: 10.1016/j.jcis.2018.04.097

Figure abstract. Schematic diagram of synthesis method and photcatalysis for as-prepared BiOxCly/BiOmBrn/BiOpIq under different conditions. [Display omitted] This paper presents an unprecedented systematic synthetic study of a controlled hydrothermal method for the preparation of bismuth oxychloride/bismuth oxybromide/bismuth oxyiodide ternary composites (BiOxCly/BiOmBrn/BiOpIq). The pH, temperature, and KCl:KBr:KI molar ratio for the reactions were adjusted to control the compositions and morphologies of BiOxCly/BiOmBrn/BiOpIq composites. Scanning electron microscopy-energy dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffraction, ultraviolet–visible diffuse reflectance spectroscopy, Brunauer–Emmett–Teller specific surface areas, photoluminescence spectroscopy, and X-ray photoelectron spectroscopy, and electron paramagnetic resonance spectroscopy were applied to the products. The photocatalytic activities of dispersions were examined by monitoring the 2-hydroxybenzoic acid (HBA) and crystal violet concentrations. Various scavengers demonstrated quenching effects. O2− was crucial to HBA degradation, whereas h+ and OH played minor roles in HBA degradation. This text hypothesizes possible photodegradation mechanisms.