Facile growth and composition-dependent photocatalytic activity of flowerlike BiOCl1−xBrx hierarchical microspheres

• DOI: 10.1016/j.apsusc.2016.08.134
• Publication Date: 2016-09-08T22:24:04Z
• Authors: Qin Qin; Yingna Guo; Dandan Zhou; Yuxin Yang; Yihang Guo
• Keywords: Tetragonal crystal system; Visible spectrum

Abstract A group of nanosheet-assembled three-dimensional BiOCl 1−x Br x hierarchical microspheres (x = 0, 0.3, 0.4, 0.5, 0.7, 0.8 and 1.0) with layered tetragonal crystal phase were prepared by 2-methoxyethanol-assisted solvothermal route and using ionic liquids as both halogen sources and structure-directing agent. By the combination of the results including XRD, XPS and UV–vis/DR spectra, lattice substitution of halogen atoms each other and then formation of BiOCl 1−x Br x solid solution was evidenced. Additionally, the BiOCl 1−x Br x microspheres exhibited interesting composition-dependent band gaps. The simulated sunlight and visible-light photocatalytic properties including degradation, mineralization and reusability of the BiOCl 1−x Br x microspheres were evaluated by selecting p -nitrophenol (PNP) and tetrabromobisphenol-A (TBBPA) as the target pollutant compounds, finding that the balance between the suitable band gap and adequate potential of the valence band in BiOCl 1−x Br x crystals dominated their photocatalytic activity. Additionally, the BiOCl 1−x Br x microspheres with advantages such as enhanced photon utilization efficiency, larger BET surface area and favorable (110) exposed reactive surface gave the positive influence on their photocatalytic activity. Based on the results of photoelectrochemistry experiment and indirect chemical probe testing, direct • O 2 − and h VB + photooxidation for the decomposition of PNP or TBBPA was revealed.