Visible light photocatalytic degradation of dyes by beta -Bi sub(2)O sub(3)/graphene nanocomposites

• Published in: Journal of alloys and compounds 2015-11, Vol.649, p.872-877
• Main Authors: Chen, Xuefu, Dai, Jianfeng, Shi, Gaofeng, Li, Lan, Wang, Guoying, Yang, Hua
• Format: Article
• Language: English
• Subjects: Alloys; Degradation; Ethyl alcohol; Graphene; Irradiation; Nanoparticles; Photocatalysis; Radicals
• ISSN: 0925-8388
• DOI: 10.1016/j.jallcom.2015.05.096

[Beta]-Bi sub(2)O sub(3) nanoparticles with an average grain size of 100 nm were synthesized by a polyacrylamide sol -gel method. Their bandgap energy is obtained by ultraviolet-visible diffuse reflectance spectroscopy is 2.37 eV. beta -Bi sub(2)O sub(3)/GR composites were fabricated by mixing beta -Bi sub(2)O sub(3) nanoparticles and graphene into absolute ethanol solution followed by thermal drying. A transmission electron microscopy observation shows that beta -Bi sub(2)O sub(3) nanoparticles are well assembled onto GR sheets. The photocatalytic activity of prepared samples was evaluated by degrading methylene blue under the irradiation of visible light. Compared to bare beta -Bi sub(2)O sub(3) nanoparticles, beta -Bi sub(2)O sub(3)/GR composites exhibit significantly enhanced photo-catalytic activity. Detected by the photoluminescence technique that of using terephthalic acid as a probe molecule, hydroxyl (*OH) radicals are found to be produced on the irradiated beta -Bi sub(2)O sub(3)/GR composites. Based on the experimental results, *OH radicals are suggested to be the major active species which is responsible for the degradation reaction.