Ternary ZnO/AgBr/Ag₂CrO₄ nanocomposites with tandem n-n heterojunctions as novel visible-light-driven photocatalysts with excellent activity

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• 作者：Mahsa Pirhashemi ; Aziz Habibi-Yangjeh ; ^{ahabibi@uma.ac.ir" class="auth_mail" title="E-mail the corresponding author}
• 关键词：ZnO/AgBr/Ag2CrO4 ; Tandem n&ndash ; n heterojunctions ; Visible-light-driven ; Photocatalyst
• 刊名：Ceramics International
• 出版年：2015
• 出版时间：December 2015
• 年：2015
• 卷：41
• 期：10
• 页码：14383-14393
• 全文大小：2406 K

文摘

Herein, we successfully prepared ternary ZnO/AgBr/Ag₂CrO₄ nanocomposites with tandem n–n heterojunctions as novel visible-light-driven photocatalysts having excellent activity. The preparation method is a facile and low temperature and employs zinc nitrate, silver nitrate, sodium hydroxide, and potassium chromate as starting materials without using any post-preparation treatments. The resultant samples were characterized using XRD, EDX, SEM, TEM, UV–vis DRS, FT-IR, and PL techniques. The results revealed that weight percent of Ag₂CrO₄ has substantial influence on degradation of rhodamine B under visible-light irradiation and the best activity was observed for the ZnO/AgBr/Ag₂CrO₄ (20%) nanocomposite. Photocatalytic activity of this nanocomposite is about 16 and 7-fold higher than those of the ZnO and ZnO/AgBr samples. Increase of the photocatalytic activity was attributed to more harvesting of the visible-light irradiation and efficiently separation of the photogenerated charge carriers due to formation of tandem n–n heterojunctions between counterparts of the nanocomposite. Moreover, the preparation time and calcination temperature significantly affect the photocatalytic activity. Based on the trapping experiments, it was shown that superoxide ions and holes have major influence on the degradation reaction.