Activity and structure-sensitivity of the water-gas shift reaction over Cu{single bond}Zn{single bond}Al mixed oxide catalysts

The activity and structure-sensitivity of the water-gas shift (WGS) reaction over Cu{single bond}Zn{single bond}Al mixed oxide catalysts were studied. Three sets of samples with different Cu/Zn and (Cu+Zn)/Al atomic ratios were prepared by coprecipitation. Depending on the cation ratio, the ternary...

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Autores principales: Ginés, M.J.L., Amadeo, N., Laborde, M., Apesteguía, C.R.
Formato: JOUR
Materias:
Copper oxide/zinc oxide/alumina
Structure-sensitivity
Water-gas shift reaction
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_0926860X_v131_n2_p283_Gines
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_0926860X_v131_n2_p283_Gines2023-10-03T15:46:42Z Activity and structure-sensitivity of the water-gas shift reaction over Cu{single bond}Zn{single bond}Al mixed oxide catalysts Ginés, M.J.L. Amadeo, N. Laborde, M. Apesteguía, C.R. Copper oxide/zinc oxide/alumina Structure-sensitivity Water-gas shift reaction The activity and structure-sensitivity of the water-gas shift (WGS) reaction over Cu{single bond}Zn{single bond}Al mixed oxide catalysts were studied. Three sets of samples with different Cu/Zn and (Cu+Zn)/Al atomic ratios were prepared by coprecipitation. Depending on the cation ratio, the ternary hydroxycarbonate precursors contained hydrotalcite, aurichalcite and/or rosasite phases. The decomposed precursors contained CuO, ZnO, ZnAl2O4, and Al2O3. The relative proportion of these phases depended on both the chemical composition of the sample and the calcination temperature employed for decomposing the precursor. After activation with hydrogen, samples were tested for the WGS reaction at 503 K. The turnover frequency of the eighteen samples tested was essentially the same (0.2-0.3 s-1) irrespective of changing the copper metal surface area between 3 and 35 m2/g Cu and the metallic copper dispersion between 0.5 and 5.0%. This indicated that the WGS reaction is a structure-insensitive reaction, as the specific reaction rate r0 (mol CO/h/g Cu) is always proportional to the copper metal surface area. Preparation of mixed oxides with a high copper dispersion is therefore required for obtaining more active catalysts. It was found that the value of the metallic copper dispersion is related to the amount of hydrotalcite contained in the hydroxycarbonate precursor: the higher the hydrotalcite content in the precursor, the higher the copper metal dispersion in the resulting catalyst and, as a consequence, the higher the catalyst activity. Ternary Cu/ZnO/Al2O3 catalysts exhibited a substantially faster WGS activity than binary Cu/ZnO catalysts. The addition of aluminium, although inactive for the WGS reaction, is required for improving the catalyst performance. © 1995 Elsevier Science B.V. All rights reserved. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_0926860X_v131_n2_p283_Gines
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Copper oxide/zinc oxide/alumina
Structure-sensitivity
Water-gas shift reaction
spellingShingle Copper oxide/zinc oxide/alumina
Structure-sensitivity
Water-gas shift reaction
Ginés, M.J.L.
Amadeo, N.
Laborde, M.
Apesteguía, C.R.
Activity and structure-sensitivity of the water-gas shift reaction over Cu{single bond}Zn{single bond}Al mixed oxide catalysts
topic_facet Copper oxide/zinc oxide/alumina
Structure-sensitivity
Water-gas shift reaction
description The activity and structure-sensitivity of the water-gas shift (WGS) reaction over Cu{single bond}Zn{single bond}Al mixed oxide catalysts were studied. Three sets of samples with different Cu/Zn and (Cu+Zn)/Al atomic ratios were prepared by coprecipitation. Depending on the cation ratio, the ternary hydroxycarbonate precursors contained hydrotalcite, aurichalcite and/or rosasite phases. The decomposed precursors contained CuO, ZnO, ZnAl2O4, and Al2O3. The relative proportion of these phases depended on both the chemical composition of the sample and the calcination temperature employed for decomposing the precursor. After activation with hydrogen, samples were tested for the WGS reaction at 503 K. The turnover frequency of the eighteen samples tested was essentially the same (0.2-0.3 s-1) irrespective of changing the copper metal surface area between 3 and 35 m2/g Cu and the metallic copper dispersion between 0.5 and 5.0%. This indicated that the WGS reaction is a structure-insensitive reaction, as the specific reaction rate r0 (mol CO/h/g Cu) is always proportional to the copper metal surface area. Preparation of mixed oxides with a high copper dispersion is therefore required for obtaining more active catalysts. It was found that the value of the metallic copper dispersion is related to the amount of hydrotalcite contained in the hydroxycarbonate precursor: the higher the hydrotalcite content in the precursor, the higher the copper metal dispersion in the resulting catalyst and, as a consequence, the higher the catalyst activity. Ternary Cu/ZnO/Al2O3 catalysts exhibited a substantially faster WGS activity than binary Cu/ZnO catalysts. The addition of aluminium, although inactive for the WGS reaction, is required for improving the catalyst performance. © 1995 Elsevier Science B.V. All rights reserved.
format JOUR
author Ginés, M.J.L.
Amadeo, N.
Laborde, M.
Apesteguía, C.R.
author_facet Ginés, M.J.L.
Amadeo, N.
Laborde, M.
Apesteguía, C.R.
author_sort Ginés, M.J.L.
title Activity and structure-sensitivity of the water-gas shift reaction over Cu{single bond}Zn{single bond}Al mixed oxide catalysts
title_short Activity and structure-sensitivity of the water-gas shift reaction over Cu{single bond}Zn{single bond}Al mixed oxide catalysts
title_full Activity and structure-sensitivity of the water-gas shift reaction over Cu{single bond}Zn{single bond}Al mixed oxide catalysts
title_fullStr Activity and structure-sensitivity of the water-gas shift reaction over Cu{single bond}Zn{single bond}Al mixed oxide catalysts
title_full_unstemmed Activity and structure-sensitivity of the water-gas shift reaction over Cu{single bond}Zn{single bond}Al mixed oxide catalysts
title_sort activity and structure-sensitivity of the water-gas shift reaction over cu{single bond}zn{single bond}al mixed oxide catalysts
url http://hdl.handle.net/20.500.12110/paper_0926860X_v131_n2_p283_Gines
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