title: Low-temperature synthesis of rose-like ZnO nanostructures using surfactin and their photocatalytic activity.
abstract: Rose-like ZnO nanostructures were synthesized by the precipitation method using a biosurfactant (surfactin) as a templating-agent stabilizer. The concentration of surfactin in the precursor solution significantly influenced the thickness and density of the petals in the rose-like structures, and all samples were of a wurtzite phase. The thickness of the petal was found to decrease with increasing surfactin concentration. The average thickness of the petals was found to be between 10 and 13 nm. Photocatalytic degradation of methylene blue using rose-like ZnO nanostuctures was investigated, and the morphology, density and thickness of the ZnO petals were found to influence the photodegradation activity. The samples with loosely-spread petals, or plate-like ZnO structures, brought about the strongest photodegradation in comparison with the dense rose-like structures. The greater activity of the loose-petal structures was correlated with their higher absorption in the UV region in comparison with the other samples. The ZnO samples prepared using low surfactin concentrations had higher rate constant values, i.e., 9.1 x 10(-3) min(-1), which revealed that the photodegradation of methylene blue under UV irradiation progressed by a pseudo first-order kinetic reaction.
authors.affiliation: Department of Earth and Environmental Sciences, National Chung Cheng University, Minhsiung, Chiayi 62102, Taiwan.
authors.forename: A Satyanarayana
authors.initials: AS
authors.lastname: Reddy
authors.forename: Yi-Hao
authors.initials: YH
authors.lastname: Kuo
authors.forename: Shashi B
authors.initials: SB
authors.lastname: Atla
authors.forename: Chien-Yen
authors.initials: CY
authors.lastname: Chen
authors.forename: Chien-Cheng
authors.initials: CC
authors.lastname: Chen
authors.forename: Ruey-Chyuan
authors.initials: RC
authors.lastname: Shih
authors.forename: Young-Fo
authors.initials: YF
authors.lastname: Chang
authors.forename: Jyoti Prakash
authors.initials: JP
authors.lastname: Maity
authors.forename: How-Ji
authors.initials: HJ
authors.lastname: Chen
mesh_terms: D002384:Catalysis; D007700:Kinetics; D055666:Lipopeptides / Q000737:chemistry*; D008751:Methylene Blue / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D010456:Peptides, Cyclic / Q000737:chemistry*; D010782:Photolysis; D013501:Surface-Active Agents / Q000737:chemistry; D013696:Temperature; D014961:X-Ray Diffraction; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D055666:Lipopeptides; D010456:Peptides, Cyclic; D013501:Surface-Active Agents; C009365:surfactin peptide; D015034:Zinc Oxide; D008751:Methylene Blue