Synthesis, characterization and photocatalytic properties of PDI/TiO 2 /activated carbon nanocomposite
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Synthesis, characterization and photocatalytic properties of PDI/TiO2/activated carbon nanocomposite Fengxia Zhang, et al. [full author details at the end of the article] Received: 24 May 2020 / Accepted: 20 July 2020 © Springer Nature B.V. 2020
Abstract 1-Hydroxy perylene diimide-doped T iO2 loaded on the activated carbon (HO-PDI/ TiO2/AC) nanocomposite was prepared by hydrothermal method. The nanocomposite was characterized by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, BET surface area, UV–Vis diffuse reflectance spectroscopy, and photoluminescence spectroscopy. The photocatalytic activity of the nanocomposite was investigated by degradation of AMX and EBT under visible light irradiation. The results indicated that the photocatalytic activity of the T iO2 increased under visible light irradiation in the presence of the HO-PDI and activated carbon. AC could disperse the HO-PDI/ TiO2 nanoparticles and inhibit their agglomeration to improve the photoreactivity, while HO-PDI could be excited to generate electrons and holes under visible-light illumination. Photogenerated holes in T iO2 could be captured by AC, and the holes can be easily moved to the surface of AC, directly initiating the photocatalytic reaction. Based on these results, a dual catalytic mechanism of AC-TiO2 involving dye sensitization and electron–hole separation was proposed. Graphic abstract
Keywords Titanium dioxide · Perylene diimide · Activated carbon · Photocatalytic
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Introduction In recent years, heterogeneous photocatalysis has been widely used in the field of environmental remediation [1, 2]. Various semiconductors such as TiO2, WO3, CdS, and ZnO have been used as photocatalysts [3–7]. Among the photocatalysts, T iO2 is the most promising photocatalyst for degradation of a variety of environmental pollutants, due to its high photosensitivity, corrosion resistibility, low cost, chemical stability, nontoxic nature and its abundance [8, 9]. However, there are still some drawbacks that limit the practical application of TiO2. First, TiO2 (anatase) can exhibit effective photocatalytic activity only under ultraviolet excitation due to its wide band gap, and second, the generated electrons and holes in T iO2 tend to recombine after being excited [10–12]. Since 1991, dye sensitization has been considered as an effective strategy to overcome the drawbacks of wideband gap photocatalysts and to absorb visible light [13, 14]. More specifically, the sensitizer can capture sunlight, produce a high energy state, inject the photo-generated electrons into the conductive band of TiO2, and thereby degrade pollutants [15, 16]. Recent researches suggest that the low electron–hole recombination can also be improved by composite dye sensitizer with semiconductor materials [17, 18]. Perylene tetracarboxylic diimide derivatives (PDIs) are promising molecules as electron transport materials due to their excellent thermal and ox
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