Synthesis and characterization of hollow mesoporous BaFe{sub 12}O{sub 19} spheres

Journal Article · Sun Feb 15 00:00:00 EST 2015 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/J.JSSC.2014.11.008· OSTI ID:22443544

Xu, Xia ^[1]; Park, Jihoon; Hong, Yang-Ki ^[1]

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1. Center for Materials for Information Technology, The University of Alabama, Tuscaloosa, AL 35487 (United States)

A facile method is reported to synthesize hollow mesoporous BaFe{sub 12}O{sub 19} spheres using a template-free chemical etching process. Hollow BaFe{sub 12}O{sub 19} spheres were synthesized by conventional spray pyrolysis. The mesoporous structure is achieved by alkaline ethylene glycol etching at 185 °C, with the porosity controlled by the heating time. The hollow porous structure is confirmed by SEM, TEM, and FIB-FESEM characterization. The crystal structure and magnetic properties are not significantly affected after the chemical etching process. The formation mechanism of the porous structure is explained by grain boundary etching. - Graphical abstract: Hollow spherical BaFe{sub 12}O{sub 19} particles are polycrystalline with both grains and grain boundaries. Grain boundaries have less ordered structure and lower stability. When the particles are exposed to high temperature alkaline ethylene glycol, the grain boundaries are etched, leaving small grooves between grains. These grooves allow ethylene glycol to diffuse inside to further etch the grains. As the grain size decreases, gaps appear on the particle surfaces, and a porous structure is finally formed. - Highlights: • Two-step synthesis method for hollow mesoporous BaFe{sub 12}O{sub 19} spheres is proposed. • Porosity of the product can be regulated by controlling the second step of chemical etching. • The crystal structure and magnetic properties are examined to be little affected during the chemical etching. • The mesoporous structure formation mechanism is explained by grain boundary etching.

• OSTI ID: 22443544
• Journal Information: Journal of Solid State Chemistry, Vol. 222; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
BARIUM COMPOUNDS
CRYSTAL STRUCTURE
ETCHING
FERRITES
GLYCOLS
GRAIN BOUNDARIES
GRAIN SIZE
HEATING
MAGNETIC PROPERTIES
NANOSTRUCTURES
PARTICLES
POLYCRYSTALS
POROSITY
POROUS MATERIALS
PYROLYSIS
SCANNING ELECTRON MICROSCOPY
STABILITY
SURFACES
SYNTHESIS
TRANSMISSION ELECTRON MICROSCOPY