Rapid synthesis of triple-layered cylindrical ZnO@SiO 2 @Ag core-shell nanostructures for photocatalytic applications
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RESEARCH PAPER
Rapid synthesis of triple-layered cylindrical ZnO@SiO2@Ag core-shell nanostructures for photocatalytic applications Gashaw Beyene & Teshome Senbeta & Belayneh Mesfin & Ni Han & Gamachis Sakata & Qinfang Zhang Received: 3 August 2020 / Accepted: 10 November 2020 # Springer Nature B.V. 2020
Abstract Core-shell nanocomposites are promising materials in the degradation of harmful chemicals released from industries/factories. In this work, ZnO@SiO2@Ag triple–layered core-shell nanocomposites synthesized by a facile chemical precipitation route at 400 °C using asprepared ZnO@SiO2 samples as a precursor were investigated for photocatalytic application. The synthesized ZnO@SiO2 and ZnO@SiO2@Ag samples were characterized using XRD, SEM, TEM, XPS, and UV-Vis spectrometer. The XRD studies showed that both nanocomposites possess the hexagonal wurtzite crystalline phase of the core ZnO. Moreover, the average crystallite sizes of ZnO@SiO2@Ag composites determined from the XRD spectra were found to be 27.98 nm and 30.56 nm for reaction times of 4 h and 12 h, respectively. The SEM Highlights • Cylindrical triple layered ZnO@SiO2@Ag CSNSs synthesized using three techniques • Optical properties of ZnO@SiO2 and ZnO@SiO2@Ag were investigated • Synthesized nanoparticles were applied for the degradation of methylene blue dye • The use of Ag as a coat enhanced photocatalytic activity of ZnO@SiO2 • ZnO@SiO2@Ag CSNSs were very stable even after recycling of five times G. Beyene : N. Han : G. Sakata : Q. Zhang (*) School of Materials Science and Engineering, Yancheng Institute of Technology, Yancheng, China e-mail: [email protected] G. Beyene : T. Senbeta : B. Mesfin : G. Sakata Department of Physics, Addis Ababa University, Addis Ababa, Ethiopia
and TEM analyses indicate that the morphologies of the samples were rod-shaped. The UV-Vis spectroscopy showed that the ZnO@SiO2@Ag nanoparticles exhibited maximum absorbance peak at 363 nm with a calculated band gap energy of 3.13 eV. In addition, the photocatalytic activity and stability were analyzed by a photoreduction method using the photodegradation property of organic methylene blue under UV-Vis light irradiation. Compared with the “bare” ZnO@SiO2 samples, the stability and photocatalytic performance of the Ag coated ZnO@SiO2@Ag nanocomposites were highly enhanced, and the reasons for the enhancement are discussed.
Keywords Core-shell nanostructure . Methylene blue . Crystallite size . Band gap energy . Photodegradation . Chemical stability
Introduction Large number of industries/factories release untreated waste water to the environment. The byproduct from dye industries are aromatic compounds, potentially toxic, and difficult to degrade. The discharge of waste water from these industries can directly affect aquatic organisms as well as human health. Moreover, these harmful byproducts have the potential to mix with water reservoirs/dams that can be used for drinking and indirectly affect human health through the food chain, reduce soil fertility, and cause serious pr
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