Ag 2 S quantum-dot-modified flower-like PbBiO 2 Br for enhanced photocatalytic degradation of crystal violet
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Ag2S quantum-dot-modified flower-like PbBiO2Br for enhanced photocatalytic degradation of crystal violet Wen Li1,2, Zhiying Liu3, Wei Song4, and Yanhua Xu3,* 1
College of Civil Engineering, Nanjing Tech University, Nanjing 211816, China School of Environmental & Safety Engineering, Changzhou University, Changzhou 213164, Jiangsu, China 3 School of Environmental Science and Engineering, Nanjing Tech University, Nanjing 211816, China 4 Changzhou Zhiheng Environmental Technology Co., Ltd, Changzhou 213164, Jiangsu, China 2
Received: 30 July 2020
ABSTRACT
Accepted: 31 August 2020
Novel Ag2S/PbBiO2Br (Ag2S/PBOB) direct Z-scheme photocatalysts were successfully synthesized for the first time by modifying flower-like PBOB with Ag2S QDs through a hydrothermal and ion-exchange way. The crystal structure, surface state, morphology, element distribution, electrochemical and optical properties of the as-prepared samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), photocurrent testing, Fourier transform infrared spectroscopy (FT-IR), ultraviolet–visible diffuse reflectance spectroscopy (UV–Vis DRS), photoluminescence (PL) technique. The obtained samples were evaluated via degradation of crystal violet (CV) under visible light irradiation. The results show that direct Z-scheme heterojunctions are formed on the interfaces between Ag2S and the PBOB, which enhance the visible light absorbance and efficient separation of photo-generated electron–hole pairs. Moreover, the 5wt%Ag2S/PBOB composite displays the highest photocatalytic activity for the degradation of CV under visible light, where the CV degradation rate is 94.4%, about 1.37 times higher than that for bare PBOB under visible light irradiation for 60 min. The enhanced photocatalytic activity of the Ag2S/PBOB composites can be attributed to strong visible light absorbance and the direct Z-scheme charge transfer mechanism. Moreover, the 5wt%Ag2S/PBOB composite also has a good stability and recyclability and has great potential in environmental protection. In addition, active species trapping experiments confirm that O2 and OH play a very important role in the degradation process. This work provides new insights and opportunities for establishing photocatalytic models in degradation of organic contaminant.
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Springer Science+Business
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https://doi.org/10.1007/s10854-020-04393-5
J Mater Sci: Mater Electron
1 Introduction Photocatalytically removing organic pollutants by employing semiconductor materials is very attractive due to the utilization abundant solar light [1, 2]. The traditional photocatalyst of wide bandgap ZnO semiconductor has been widely researched due to its excellent optical and electronic properties, low cost, non-toxicity, and relatively high chemical stability [3–5]. However, ZnO has a relatively wide bandgap, limiting its practical applic
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