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Title: Microwave synthesis and photocatalytic activities of ZnO bipods with different aspect ratios

Abstract

Highlights: • We synthesized linked ZnO nanorods by a facile microwave method. • The effect of reaction parameters on ZnO was investigated. • ZnO bipods with different aspect ratios were prepared. • The photocatalytic performance of ZnO bipods was evaluated. - Abstract: Linked ZnO nanorods have been successfully prepared via a facile microwave method without any post-synthesis treatment. The X-ray diffraction (XRD) patterns indicated the precursor had completely transformed into the pure ZnO crystal. The images of field emitting scanning electron microscope (FESEM) and transmission electron microscope (TEM) showed that linked ZnO nanorods consisted predominantly of ZnO bipods. The formation process of the ZnO bipods was clearly discussed. ZnO bipods with different aspect ratios have been obtained by tuning the concentrations of reagents and microwave power. Moreover, the photocatalytic performance of ZnO bipods with different aspect ratios for degradation of methylene blue was systematically evaluated. The results of photocatalytic experiments showed that the photocatalytic activity increased with the aspect ratios of ZnO bipods increased. The reason is that ZnO bipods with larger aspect ratio have higher surface area, which can absorb more MB molecules to react with ·OH radicals.

Authors:
;  [1];  [2]; ;  [2]
  1. Analysis and Testing Center, Shandong University of Technology, Zibo 255100 (China)
  2. State Key Laboratory of Plastic Forming Simulation and Die and Mould Technology, Huazhong University of Science and Technology, Wuhan 430074, Hubei (China)
Publication Date:
OSTI Identifier:
22581437
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Research Bulletin; Journal Volume: 74; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ASPECT RATIO; CONCENTRATION RATIO; CRYSTAL GROWTH; CRYSTALS; HYDROXYL RADICALS; METHYLENE BLUE; MICROWAVE RADIATION; MOLECULES; NANOSTRUCTURES; PHOTOCATALYSIS; SCANNING ELECTRON MICROSCOPY; SURFACE AREA; SYNTHESIS; TRANSMISSION ELECTRON MICROSCOPY; X-RAY DIFFRACTION; ZINC OXIDES

Citation Formats

Sun, Fazhe, Zhao, Zengdian, Qiao, Xueliang, E-mail: xuelqiao@163.com, Tan, Fatang, and Wang, Wei. Microwave synthesis and photocatalytic activities of ZnO bipods with different aspect ratios. United States: N. p., 2016. Web. doi:10.1016/J.MATERRESBULL.2015.10.054.
Sun, Fazhe, Zhao, Zengdian, Qiao, Xueliang, E-mail: xuelqiao@163.com, Tan, Fatang, & Wang, Wei. Microwave synthesis and photocatalytic activities of ZnO bipods with different aspect ratios. United States. doi:10.1016/J.MATERRESBULL.2015.10.054.
Sun, Fazhe, Zhao, Zengdian, Qiao, Xueliang, E-mail: xuelqiao@163.com, Tan, Fatang, and Wang, Wei. Mon . "Microwave synthesis and photocatalytic activities of ZnO bipods with different aspect ratios". United States. doi:10.1016/J.MATERRESBULL.2015.10.054.
@article{osti_22581437,
title = {Microwave synthesis and photocatalytic activities of ZnO bipods with different aspect ratios},
author = {Sun, Fazhe and Zhao, Zengdian and Qiao, Xueliang, E-mail: xuelqiao@163.com and Tan, Fatang and Wang, Wei},
abstractNote = {Highlights: • We synthesized linked ZnO nanorods by a facile microwave method. • The effect of reaction parameters on ZnO was investigated. • ZnO bipods with different aspect ratios were prepared. • The photocatalytic performance of ZnO bipods was evaluated. - Abstract: Linked ZnO nanorods have been successfully prepared via a facile microwave method without any post-synthesis treatment. The X-ray diffraction (XRD) patterns indicated the precursor had completely transformed into the pure ZnO crystal. The images of field emitting scanning electron microscope (FESEM) and transmission electron microscope (TEM) showed that linked ZnO nanorods consisted predominantly of ZnO bipods. The formation process of the ZnO bipods was clearly discussed. ZnO bipods with different aspect ratios have been obtained by tuning the concentrations of reagents and microwave power. Moreover, the photocatalytic performance of ZnO bipods with different aspect ratios for degradation of methylene blue was systematically evaluated. The results of photocatalytic experiments showed that the photocatalytic activity increased with the aspect ratios of ZnO bipods increased. The reason is that ZnO bipods with larger aspect ratio have higher surface area, which can absorb more MB molecules to react with ·OH radicals.},
doi = {10.1016/J.MATERRESBULL.2015.10.054},
journal = {Materials Research Bulletin},
number = ,
volume = 74,
place = {United States},
year = {Mon Feb 15 00:00:00 EST 2016},
month = {Mon Feb 15 00:00:00 EST 2016}
}
  • Highlights: • Ag/ZnO nanocomposites were synthesized by a microwave-assisted combustion method. • Ag/ZnO nanocomposites exhibited improved photocatalytic activities under UV irradiation. • Poorer photocatalytic performances were obtained under visible-light irradiation. - Abstract: Ag/ZnO nanocomposites were synthesized by a rapid one-step microwave-assisted combustion method. The as-synthesized samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, photoluminescence and ultraviolet–visible spectrophotometry. XRD results showed that hexagonal ZnO and cubic Ag were obtained. Ag nanoparticles were chemically attached on the surface of ZnO. The decrease in the energy band gap of Ag/ZnO nanocomposites and the photoluminescence quenching weremore » observed while the Ag content was increased. Furthermore, the introduction of Ag nanoparticles leads to significantly improved photocatalytic activities in the case of ultraviolet irradiation, but in the case of visible-light irradiation opposite results were obtained. The corresponding mechanism was discussed in detail.« less
  • A new and rapid method for silica coating of ZnO nanoparticles by the simple microwave irradiation technique is reported. Silica-coated ZnO nanoparticles were characterized by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), high-resolution transmission electron microscopy (HR-TEM), CHN elemental analysis and zeta potential measurements. The FT-IR spectra and XPS clearly confirmed the silica coating on ZnO nanoparticles. The results of XPS analysis showed that the elements in the coating at the surface of the ZnO nanoparticles were Zn, O and Si. HR-TEM micrographs revealed a continuous and uniform dense silica coating layer of about 3 nm in thicknessmore » on the surface of ZnO nanoparticles. In addition, the silica coating on the ZnO nanoparticles was confirmed by the agreement in the zeta potential of the silica-coated ZnO nanoparticles with that of SiO{sub 2}. The results of the photocatalytic degradation of methylene blue (MB) in aqueous solution showed that silica coating effectively reduced the photocatalytic activity of ZnO nanoparticles. Silica-coated ZnO nanoparticles showed excellent UV shielding ability and visible light transparency.« less
  • Titanium nitride nanorods have been successfully synthesized by low temperature solid-state metathesis of titanium (III) chloride and sodium azide without using any organic solvent. The conditions required for the synthesis of these nanorods have been optimized. It was found that the temperature and time of reaction had a significant effect on the product morphology. Thermal treatment at 360 deg. C, for 3 days gave the nanorods of the aspect ratio {approx}10 (i.e. diameter {approx}50nm and length {approx}500nm), whereas the thermal treatment at 400 deg. C for 3 days gave the nanorods of the aspect ratio {approx}50 (i.e. diameter {approx}50nm andmore » length {approx}2-3{mu}m). Scanning and transmission electron microscopies clearly showed the rod-type morphology. Further evidence for the phase purity and crystallinity of titanium nitride nanorods was given by X-ray diffraction, field emission high-resolution electron microscopy and X-ray photoelectron spectroscopy analyses.« less
  • ZnO composite films consisting of ZnO nanorods and nanosheets were prepared by low-temperature hydrothermal processing at 80 °C on seeded glass substrates. The seed layer was coated on glass substrates by sol–gel dip-coating and pre-heated at 300 °C for 10 min prior to hydrothermal growth. The size of the grain formed after pre-heat treatment was ∼40 nm. A preferred orientation seed layer at the c-axis was obtained, which promoted vertical growth of the ZnO nanorod arrays and formation of the ZnO nanosheets. X-ray diffraction patterns and high-resolution transmission electron microscope (HR-TEM) images confirmed that the ZnO nanorods and nanosheets consistmore » of single crystalline and polycrystalline structures, respectively. Room temperature photoluminescence spectra of the ZnO nanorod–nanosheet composite films exhibited band-edge ultraviolet (UV) and visible emission (blue and green) indicating the formation of ZnO crystals with good crystallinity and are supported by Raman scattering results. The formation of one-dimensional (1D) ZnO nanorod arrays and two-dimensional (2D) ZnO nanosheet films using seeded substrates in a single low-temperature hydrothermal step would be beneficial for realization of device applications that utilize substrates with limited temperature stability. The ZnO nanorods and nanosheets composite structure demonstrated higher photocatalytic activity during degradation of aqueous methylene blue under visible-light irradiation. -- Graphical abstract: Schematic illustration of ZnO nanorod–nanosheet composite structure formation by hydrothermal at low-temperature of 80 °C against time. Highlights: • Novel simultaneous formation of ZnO nanorods and nanosheets composite structure. • Facile single hydrothermal step formation at low-temperature. • Photoluminescence showed ultraviolet and visible emission. • Feasible application on substrates with low temperature stability. • Improved photocatalytic activity under visible-light irradiation.« less
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