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Pamplona, Spain

Laguna O.H.,University of Seville | Hernandez W.Y.,University of Seville | Arzamendi G.,Edificio de Los Acebos | Gandia L.M.,Edificio de Los Acebos | And 2 more authors.

Hydrogen produced from the conversion of hydrocarbons or alcohols contains variable amounts of CO that should be removed for some applications such as feeding low-temperature polymer electrolyte membrane fuel cells (PEMFCs). The CO preferential oxidation reaction (PROX) is particularly well-suited for hydrogen purification for portable and on-board applications. In this work, the synthesis and characterization by XRF, BET, XRD, Raman spectroscopy and H 2-TPR of a gold catalyst supported on a copper-cerium mixed oxide (AuCeCu) for the PROX reaction are presented. The comparison of this catalyst with the copper-cerium mixed oxide (CeCu) revealed that the experimental procedure used for the deposition of gold gave rise to the loss of reducible material by copper lixiviation. However, the AuCeCu solid was more active for CO oxidation at low temperature. A kinetic study has been carried over the AuCeCu catalyst for the PROX reaction and compared with that of the CeCu catalyst. The main difference between the models affected the contribution of the CO adsorption term. This fact may be related to the surface electronic activity produced by the interaction of the cationic species in the AuCeCu solid, able to create more active sites for the CO adsorption and activation in the presence of gold. © 2013 Elsevier Ltd. All rights reserved. Source

Garces S.I.,Edificio de Los Acebos | Villarroel-Rocha J.,National University of San Luis | Sapag K.,National University of San Luis | Korili S.A.,Edificio de Los Acebos | Gil A.,Edificio de Los Acebos
Industrial and Engineering Chemistry Research

The adsorption of CO2 on several microporous materials has been measured at various temperatures (263, 273, 283, and 293 K) over a wide range of pressures. The porous materials studied were three zeolites (5A, 13A, and 13X), two metal-organic frameworks (Basolite A100 and Basolite Z1200), an activated carbon, and two pillared clays (Al-PILC and Zr-PILC). The data obtained were fitted to the Freundlich, Langmuir, and Toth isotherms. Various methods were used to calculate the Henry's law constants. The values found for the zeolites, which ranged from 8.95 to 36.02 mmol/kPa·g at 273 K, were much higher than those for the metal-organic frameworks, activated carbon, and pillared clays, which ranged from 0.012 to 0.200 mmol/kPa·g at the same temperature. The isosteric heats of adsorption of CO2 on the materials were calculated using the Clausius-Clapeyron equation, and the adsorbent-CO2 affinity was found to increase in the order Z1200 ≈ 13X ≈ 13A < 5A < Zr-PILC < A100 ≈ AC ≈ Al-PILC at low loadings. © 2013 American Chemical Society. Source

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