One-pot solvothermal synthesis of three-dimensional (3D) BiOI/BiOCl composites with enhanced visible-light photocatalytic activities for the degradation of bisphenol-A

• Published in: Journal of hazardous materials 2012-09, Vol.233-234, p.122-130
• Main Authors: Xiao, Xin, Hao, Rong, Liang, Min, Zuo, Xiaoxi, Nan, Junmin, Li, Laisheng, Zhang, Weide
• Format: Article
• Language: English
• Subjects: absorption; Applied sciences; Benzhydryl Compounds - chemistry; Benzhydryl Compounds - radiation effects; BiOI/BiOCl composites; Bismuth - chemistry; Bismuth - radiation effects; Bisphenol-A; Catalysis; Catalytic reactions; Chemistry; Exact sciences and technology; General and physical chemistry; Iodides - chemistry; Iodides - radiation effects; irradiation; Light; liquid chromatography; mass spectrometry; Microspheres; mineralization; oxidation; Phenols - chemistry; Phenols - radiation effects; Photocatalysis; photocatalyst; Photodegradation mechanism; Photolysis; pollutants; Pollution; recycling; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Visible light; Water Pollutants, Chemical - chemistry; Water Pollutants, Chemical - radiation effects; Water Purification - methods
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2012.06.062

[Display omitted] ► Synthesis of 3D BiOI/BiOCl microspheres by a one-pot template-free solvothermal method. ► Photocatalyst is BiOI/BiOCl composites. ► BiOI/BiOCl composites have enhanced visible-light photocatalytic ability to bisphenol-A. ► A simple and direct photodegradation pathway of bisphenol-A is proposed. Three-dimensional (3D) BiOI/BiOCl composite microspheres with enhanced visible-light photodegradation activity of bisphenol-A (BPA) are synthesized by a simple, one-pot, template-free, solvothermal method using BiI3 and BiCl3 as precursors. These 3D hierarchical microspheres with heterojunction structures are composed of 2D nanosheets and have composition-dependent absorption properties in the ultraviolet and visible light regions. The photocatalytic oxidation of BPA over BiOI/BiOCl composites followed pseudo first-order kinetics according to the Langmuir–Hinshelwood model. The highest photodegradation efficiency of BPA, i.e., nearly 100%, was observed with the BiOI/BiOCl composite (containing 90% BiOI) using a catalyst dosage of 1gL−1 in the BPA solution (C0=20mgL−1, pH=7.0) under visible light irradiation for 60min. Under these conditions, the reaction rate constant was more than 4 and 20 times greater than that of pure BiOI and the commercially available Degussa P25, respectively. The superior photocatalytic activity of this composite catalyst is attributed to the suitable band gap energies and the low recombination rate of the photogenerated electron–hole pairs due to the presence of BiOI/BiOCl heterostructures. Only one intermediate at m/z 151 was observed in the photodegradation process of BPA by liquid chromatography combined with mass spectrometry (LC–MS) analysis, and a simple and hole-predominated photodegradation pathway of BPA was subsequently proposed. Furthermore, this photocatalyst exhibited a high mineralization ratio, high stability and easy separation for recycling use, suggesting that it is a promising photocatalyst for the removal of BPA pollutants.