Journal of Colloid and Interface Science 474 (2016) 103–113
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Photosensitization of ZnO by AgBr and Ag2CO3: Nanocomposites with tandem n-n heterojunctions and highly enhanced visible-light photocatalytic activity Mahsa Pirhashemi, Aziz Habibi-Yangjeh ⇑ Department of Chemistry, Faculty of Science, University of Mohaghegh Ardabili, P.O. Box 179, Ardabil, Iran
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Article history: Received 10 March 2016 Revised 14 April 2016 Accepted 15 April 2016 Available online 19 April 2016 Keywords: Photosensitization Photocatalysts ZnO/AgBr/Ag2CO3 Visible-light-driven
a b s t r a c t Facile ultrasonic-irradiation method was applied for photosensitization of ZnO by combining with AgBr and Ag2CO3 particles through preparation of novel ternary nanocomposites. The prepared samples were characterized by XRD, SEM, TEM, EDX, UV–Vis DRS, FT-IR, BET, and PL techniques. Photocatalytic activity was investigated by degradation of rhodamine B under visible-light irradiation. It was found that photocatalytic activity of the ZnO was greatly enhanced by coupling with AgBr and Ag2CO3 particles, as narrow band gap semiconductors, through formation of tandem n-n heterojunctions. The nanocomposite with 20% of Ag2CO3 displayed the highest photocatalytic activity with the degradation rate constants which are nearly 122, 31, and 25 times higher than those of the ZnO, ZnO/AgBr, and ZnO/Ag2CO3 samples, respectively. Moreover, the trapping experiments confirmed that superoxide ion radicals and holes are the main active species responsible for the degradation reaction. Finally, it was also demonstrated that the ternary ZnO/AgBr/Ag2CO3 (20%) nanocomposite has enhanced activity in degradation of methylene blue and methyl orange. Hence, this work shows a great potential of the ternary photocatalyst for purification of contaminated water from organic pollutants. Ó 2016 Elsevier Inc. All rights reserved.
1. Introduction
⇑ Corresponding author. E-mail address:
[email protected] (A. Habibi-Yangjeh). http://dx.doi.org/10.1016/j.jcis.2016.04.022 0021-9797/Ó 2016 Elsevier Inc. All rights reserved.
It is believed that environmental and energy issues are the main challenges that the human being is facing in the present century. Being as green, high efficiency, and effective technology,
