Visible-light photosensitization of ZnO by Bi2MoO6 and AgBr: Role of tandem n-n heterojunctions in efficient charge transfer and photocatalytic performances

• Published in: Materials chemistry and physics Vol. 214; pp. 107 - 119
• Main Authors: Pirhashemi, Mahsa, Habibi-Yangjeh, Aziz
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.08.2018
• Subjects: n-n heterojunction; Photosensitization; Visible-light active; ZnO/Bi2MoO6/AgBr; Photosensitization; ZnO/Bi2MoO6/AgBr; Visible-light active; n-n heterojunction
• ISSN: 0254-0584; 1879-3312
• DOI: 10.1016/j.matchemphys.2018.04.089

Efficient visible-light active ZnO/Bi2MoO6/AgBr nanocomposites were fabricated using ultrasonic-assisted method. Crystallinity, structural, morphological, optical, and textural features of the photocatalysts were investigated by XRD, SEM, TEM, EDX, FT-IR, UV–Vis DRS, PL, and BET techniques. Photocatalytic performance of the ZnO sample was remarkably increased by combining with Bi2MoO6 and AgBr, due to formation of tandem n-n heterojunctions. The as-prepared ZnO/Bi2MoO6/AgBr nanocomposites exhibited excellent photocatalytic activity and stability under visible light in comparison with the ZnO, ZnO/Bi2MoO6, and ZnO/AgBr samples. About ∼97% of RhB was removed in 70 min by the optimized ZnO/Bi2MoO6/AgBr (20%) nanocomposite, which is 76.4, 4.75, and 17.3 times as fast as the ZnO, ZnO/Bi2MoO6 (20%) and ZnO/AgBr (20%) photocatalysts, respectively. It was confirmed that due to improved utilization of visible light, considerable separation of the charge carriers, and enlarged surface area, the ZnO/Bi2MoO6/AgBr (20%) nanocomposite exhibited greatly improved photocatalytic activity in degradations of various dye contaminants under visible-light illumination. In addition, plausible photocatalytic degradation mechanism for the highly enhanced performances were also proposed. [Display omitted] •ZnO/Bi2MoO6/AgBr nanocomposites as efficient photocatalysts are reported.•The ZnO/Bi2MoO6/AgBr (20%) nanocomposite exhibited the highest activity.•Activity was 76.4-folds greater than ZnO in RhB degradation under visible light.•The enhanced activity was attributed to tandem n-n heterojunctions.