Thermal, solution and reductive decomposition of Cu-Al layered double hydroxides into oxide products

Journal Article · Fri May 15 04:00:00 EDT 2009 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2009.02.003· OSTI ID:21370397

Britto, Sylvia ^[1]

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1. Department of Chemistry, Central College, Bangalore University, Bangalore 560 001 (India)

Cu-Al layered double hydroxides (LDHs) with [Cu]/[Al] ratio 2 adopt a structure with monoclinic symmetry while that with the ratio 0.25 adopt a structure with orthorhombic symmetry. The poor thermodynamic stability of the Cu-Al LDHs is due in part to the low enthalpies of formation of Cu(OH){sub 2} and CuCO{sub 3} and in part to the higher solubility of the LDH. Consequently, the Cu-Al LDH can be decomposed thermally (150 deg. C), hydrothermally (150 deg. C) and reductively (ascorbic acid, ambient temperature) to yield a variety of oxide products. Thermal decomposition at low (400 deg. C) temperature yields an X-ray amorphous residue, which reconstructs back to the LDH on soaking in water or standing in the ambient. Solution decomposition under hydrothermal conditions yields tenorite at 150 deg. C itself. Reductive decomposition yields a composite of Cu{sub 2}O and Al(OH){sub 3}, which on alkali-leaching of the latter, leads to the formation of fine particles of Cu{sub 2}O (<1 {mu}m). - Graphical abstract: SEM image of (a) the Cu{sub 2}O-Al(OH){sub 3} composite obtained on reductive decomposition of CuAl{sub 4}-LDH and (b) Cu{sub 2}O obtained on leaching of Al(OH){sub 3} from (a).

• OSTI ID: 21370397
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 5 Vol. 182; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ALUMINIUM COMPOUNDS
ALUMINIUM HYDROXIDES
AMBIENT TEMPERATURE
ASCORBIC ACID
CARBON COMPOUNDS
CARBONATES
CHALCOGENIDES
CHEMICAL REACTIONS
COPPER CARBONATES
COPPER COMPOUNDS
COPPER HYDROXIDES
COPPER OXIDES
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DECOMPOSITION
DISPERSIONS
DISSOLUTION
ELECTRON MICROSCOPY
ENTHALPY
FORMATION HEAT
HOMOGENEOUS MIXTURES
HYDROGEN COMPOUNDS
HYDROXIDES
LEACHING
MICROSCOPY
MIXTURES
MONOCLINIC LATTICES
ORTHORHOMBIC LATTICES
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
PYROLYSIS
REACTION HEAT
SCANNING ELECTRON MICROSCOPY
SEPARATION PROCESSES
SOLUBILITY
SOLUTIONS
STABILITY
TEMPERATURE RANGE
TEMPERATURE RANGE 0400-1000 K
THERMOCHEMICAL PROCESSES
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
VITAMINS