skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Acid and redox properties of mixed oxides prepared by calcination of chromate-containing layered double hydroxides

Abstract

Layered double hydroxides (LDHs) with Mg and Al in the layers and carbonate, nitrate or chloride in the interlayer, or with Zn and Al in the layers and chloride in the interlayer, have been prepared by coprecipitation, and have been used as precursors to prepare chromate-containing LDHs. All these systems, as well as those obtained upon their calcination up to 800 deg. C, have been characterised by powder X-ray diffraction, FT-IR and vis-UV spectroscopies, temperature-programmed reduction (TPR), nitrogen adsorption at -196 deg. C for surface texture and porosity assessment, and FT-IR monitoring of pyridine adsorption for surface acidity determination. The results obtained show that the crystallinity of the chromate-containing LDH depends on the precursor used. The layered structure of the Mg, Al systems is stabilised up to 400 deg. C upon incorporation of chromate; however, the Zn,Al-chromate samples collapse between 200 and 300 deg. C, with simultaneous formation of ZnO. Calcination of the samples above 400 deg. C gives rise to a reduction of Cr(VI) to Cr(III), as concluded from vis-UV spectroscopic studies. The TPR profiles show that chromate in ZnAl hydrotalcite is more easily reduced than that incorporated in the magnesium ones. Moderately strong surface Lewis acid sites existmore » in all samples calcined below 500 deg. C.« less

Authors:
 [1];  [1];  [1];  [1];  [2]
  1. Dpto. Quimica Inorganica, Universidad de Salamanca, 37008-Salamanca (Spain)
  2. Dpto. Quimica Inorganica, Universidad de Salamanca, 37008-Salamanca (Spain). E-mail: vrives@usal.es
Publication Date:
OSTI Identifier:
20784799
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 178; Journal Issue: 11; Other Information: DOI: 10.1016/j.jssc.2005.09.014; PII: S0022-4596(05)00422-6; Copyright (c) 2005 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:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ALUMINIUM COMPOUNDS; CALCINATION; CARBONATES; CHLORIDES; COPRECIPITATION; FOURIER TRANSFORMATION; HYDROXIDES; INFRARED SPECTRA; LAYERS; LEWIS ACIDS; MAGNESIUM COMPOUNDS; NITRATES; PYRIDINE; X-RAY DIFFRACTION; ZINC OXIDES

Citation Formats

Arco, M. del, Carriazo, D., Martin, C., Perez-Grueso, A.M., and Rives, V.. Acid and redox properties of mixed oxides prepared by calcination of chromate-containing layered double hydroxides. United States: N. p., 2005. Web. doi:10.1016/j.jssc.2005.09.014.
Arco, M. del, Carriazo, D., Martin, C., Perez-Grueso, A.M., & Rives, V.. Acid and redox properties of mixed oxides prepared by calcination of chromate-containing layered double hydroxides. United States. doi:10.1016/j.jssc.2005.09.014.
Arco, M. del, Carriazo, D., Martin, C., Perez-Grueso, A.M., and Rives, V.. Tue . "Acid and redox properties of mixed oxides prepared by calcination of chromate-containing layered double hydroxides". United States. doi:10.1016/j.jssc.2005.09.014.
@article{osti_20784799,
title = {Acid and redox properties of mixed oxides prepared by calcination of chromate-containing layered double hydroxides},
author = {Arco, M. del and Carriazo, D. and Martin, C. and Perez-Grueso, A.M. and Rives, V.},
abstractNote = {Layered double hydroxides (LDHs) with Mg and Al in the layers and carbonate, nitrate or chloride in the interlayer, or with Zn and Al in the layers and chloride in the interlayer, have been prepared by coprecipitation, and have been used as precursors to prepare chromate-containing LDHs. All these systems, as well as those obtained upon their calcination up to 800 deg. C, have been characterised by powder X-ray diffraction, FT-IR and vis-UV spectroscopies, temperature-programmed reduction (TPR), nitrogen adsorption at -196 deg. C for surface texture and porosity assessment, and FT-IR monitoring of pyridine adsorption for surface acidity determination. The results obtained show that the crystallinity of the chromate-containing LDH depends on the precursor used. The layered structure of the Mg, Al systems is stabilised up to 400 deg. C upon incorporation of chromate; however, the Zn,Al-chromate samples collapse between 200 and 300 deg. C, with simultaneous formation of ZnO. Calcination of the samples above 400 deg. C gives rise to a reduction of Cr(VI) to Cr(III), as concluded from vis-UV spectroscopic studies. The TPR profiles show that chromate in ZnAl hydrotalcite is more easily reduced than that incorporated in the magnesium ones. Moderately strong surface Lewis acid sites exist in all samples calcined below 500 deg. C.},
doi = {10.1016/j.jssc.2005.09.014},
journal = {Journal of Solid State Chemistry},
number = 11,
volume = 178,
place = {United States},
year = {Tue Nov 15 00:00:00 EST 2005},
month = {Tue Nov 15 00:00:00 EST 2005}
}