Facile synthesis and microwave absorbability of C@Ni–NiO core–shell hybrid solid sphere and multi-shelled NiO hollow sphere

Journal Article · Sat Nov 15 00:00:00 EST 2014 · Materials Characterization

DOI:https://doi.org/10.1016/J.MATCHAR.2014.08.019· OSTI ID:22403581

Wu, Hongjing ^[1]; Wu, Guanglei ^[2]; Wu, Qiaofeng; Wang, Liuding ^[1]

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1. Department of Applied Physics, Northwestern Polytechnical University, Xi'an (China)
2. Center of Nanomaterials for Renewable Energy (CNRE), State Key Lab of Electrical Insulation and Power Equipment, School of Electrical Engineering, Xi'an Jiaotong University, Xi'an (China)

We reported the preparation of C@Ni–NiO core–shell hybrid solid spheres or multi-shelled NiO hollow spheres by combining a facile hydrothermal route with a calcination process in H{sub 2} or air atmosphere, respectively. The synthesized C@Ni–NiO core–shell solid spheres with diameters of approximately 2–6 μm were in fact built from dense NiO nanoparticles coated by random two-dimensional metal Ni nanosheets without any visible pores. The multi-shelled NiO hollow spheres were built from particle-like ligaments and there are a lot of pores with size of several nanometers on the surface. Combined Raman spectra with X-ray photoelectron spectra (XPS), it suggested that the defects in the samples play a limited role in the dielectric loss. Compared with the other samples, the permeability of the samples calcined in H{sub 2} and air was increased slightly and the natural resonance frequency shifted to higher frequency (7, 11 and 14 GHz, respectively), leading to an enhancement of microwave absorption property. For the sample calcined in H{sub 2}, an optimal reflection loss less than − 10 was obtained at 7 GHz with a matching thickness of 5.0 mm. Our study demonstrated the potential application of C@Ni–NiO core–shell hybrid solid sphere or multi-shelled NiO hollow sphere as a more efficient electromagnetic (EM) wave absorber. - Highlights: • C@Ni–NiO core–shell hybrid solid sphere was synthesized by a facile method. • Multi-shelled NiO hollow sphere was synthesized by a facile method. • It suggested that the defects in the samples play a limited role in dielectric loss. • The permeability of the samples calcined in H{sub 2} and air was increased. • Microwave absorbability of C@Ni–NiO core–shell hybrid solid sphere was investigated.

• OSTI ID: 22403581
• Journal Information: Materials Characterization, Vol. 97; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1044-5803
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABSORPTION
AIR
CALCINATION
COMPARATIVE EVALUATIONS
DIELECTRIC MATERIALS
GHZ RANGE
HYDROGEN
MICROWAVE RADIATION
NANOPARTICLES
NANOSTRUCTURES
NICKEL
NICKEL OXIDES
PERMEABILITY
RAMAN SPECTRA
SCANNING ELECTRON MICROSCOPY
SOLIDS
SPHERES
TRANSMISSION ELECTRON MICROSCOPY
TWO-DIMENSIONAL SYSTEMS
X-RAY PHOTOELECTRON SPECTROSCOPY