Nanosized Ni–Al layered double hydroxides—Structural characterization

Journal Article · Wed May 15 04:00:00 EDT 2013 · Materials Research Bulletin

DOI:https://doi.org/10.1016/J.MATERRESBULL.2013.01.030· OSTI ID:22290430

Jitianu, Mihaela ^[1]; Gunness, Darren C. ^[1]; Aboagye, Doreen E. ^[2]; Zaharescu, Maria ^[3]; Jitianu, Andrei ^[2]

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1. William Paterson University, Department of Chemistry, 300 Pompton Road, Wayne, NJ 07470 (United States)
2. Lehman College – City University of New York, Department of Chemistry, Davis Hall, 250 Bedford Boulevard West, Bronx, NY 10468 (United States)
3. Institute of Physical Chemistry, 202 Splaiul Independentei, 060021 Bucharest (Romania)

Highlights: ► The takovite anionic clays were obtained using the sol–gel method. ► The effect of samples’ composition on the structural and textural characteristics has been investigated. ► X-ray analysis. ► FTIR spectroscopy evidenced a disordered interlayer structure. ► FESEM and TEM analysis showed that the samples have high porosity. - Abstract: Takovite, a natural mineral with the formula Ni{sub 6}Al{sub 2}(OH){sub 6}CO{sub 3}·5H{sub 2}O belongs to the large class of layered double hydroxides (LDHs) and contains positively charged Ni(II) and Al(III) layers alternating with layers containing carbonate ions and water molecules. Mesoporous takovite-type layered double hydroxides (LDH) of the general formula [Ni{sub 1−x}Al{sub x}(OH){sub 2}]{sup x+}(CO{sub 3}{sup 2−}){sub x/2}·nH{sub 2}O with different Ni/Al molar ratios (1.9–2.8) have been successfully synthesized by the sol–gel method, followed by anionic exchange using nickel acetylacetonate and aluminum isopropylate as cation precursors. A single LDH phase and an anisotropic growth of very small crystallites (below 4 nm) have been evidenced by X-ray diffraction. The effect of samples’ composition on their structural and textural characteristics has been investigated. The BET surface area values are in the range of 100–122 m{sup 2}/g. BJH pore radius decreased with increase in the Al(III) content in the LDHs. FESEM micrographs show large aggregates of highly porous LDH particles, while TEM analysis reveals irregular agglomerates of crystallites, among which some of them displayed a developing hexagonal shape. The average particle size variation with the Al(III) content in the samples follows the same trend as the pore radius, the sample with the highest Ni/Al ratio displaying also the smallest particle size. This sample becomes even more interesting, since TEM analysis shows agglomerates with inside circular structures, feature not observed for the other Ni/Al ratios investigated.

• OSTI ID: 22290430
• Journal Information: Materials Research Bulletin, Journal Name: Materials Research Bulletin Journal Issue: 5 Vol. 48; ISSN MRBUAC; ISSN 0025-5408
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ABSORPTION SPECTROSCOPY
ALUMINIUM
CARBONATES
CATIONS
CLAYS
INFRARED SPECTRA
INORGANIC COMPOUNDS
LAYERS
NANOSTRUCTURES
NICKEL
PARTICLE SIZE
POROUS MATERIALS
SURFACE AREA
TRANSMISSION ELECTRON MICROSCOPY
WATER