TY - JOUR
T1 - Investigation of Sm2O3–CeO2-supported palladium catalysts for the reforming of methanol: The role of the support
AU - Gomez-Sainero, L M
AU - Baker, Richard Thornton
AU - Metcalfe, I S
AU - Sahibzada, M
AU - Concepcion, P
AU - Lopez-Nieto, J M
N1 - Use of SOFCs both at lower temperatures and with alcohol fuels is highly economically desirable but demanding of the anode catalyst. Here, the kinetic performance of a new catalyst formulation is related to its chemical and physical characteristics. Conclusions are drawn about the active sites and the reaction mechanisms involved.
PY - 2005/10/10
Y1 - 2005/10/10
N2 - With a view to their use as catalytic anode materials for direct methanol solid oxide fuel cells (DM-SOFCs), the performance of Pd/CeO2-SM2O3 (Pd/CS), Pd/CeO2 and Pd/SM2O3 catalysts in the steam reforming of methanol as well as their physicochemical properties - analyzed by N-2 adsorption, XRD, temperature programmed reduction (TPR), CO chemisorption and X-ray photoelectron spectroscopy (XPS) - have been investigated. The catalytic activity in methanol steam reforming was evaluated in a tubular microreactor at atmospheric pressure in the 300-500 degrees C reaction temperature interval (space velocity = 0.32 mol/(h g(cat)) H2O/CH3OH molar ratio = 1.2, methanol concentration 15 mole%). H-2, CO and CO2 were the main reaction products. Methanol conversions up to 72% and H-2 productivities as high as 0.46 mol/(h g(cat)) were obtained on the Pd/CS catalyst. Moreover, low H-2 productivity (0.09 mol/(h g(cat))) was found on the Pd/CeO2 catalyst, while Pd/Sm2O3 appeared to be inactive. This behaviour can be partly assigned to the higher dispersion and the more favourable distribution of Pd particles observed in the Pd/CS catalyst. A strong association of Pd and samarium oxide and an enrichment in both components at the external surface of the Pd/CS catalyst grains was found by means of TPR and XPS. This could be explained by the partial dissolution of Sm2O3 in the acid medium used during catalyst preparation leading to the re-precipitation of a Pd/Sm-containing phase. Higher activity per exposed Pd atom was also observed for the Pd/CS catalyst. This was attributed to enhancement of diffusion and adsorption of reactants on the basic sites of the Sm-containing support. (c) 2005 Elsevier B.V. All rights reserved.
AB - With a view to their use as catalytic anode materials for direct methanol solid oxide fuel cells (DM-SOFCs), the performance of Pd/CeO2-SM2O3 (Pd/CS), Pd/CeO2 and Pd/SM2O3 catalysts in the steam reforming of methanol as well as their physicochemical properties - analyzed by N-2 adsorption, XRD, temperature programmed reduction (TPR), CO chemisorption and X-ray photoelectron spectroscopy (XPS) - have been investigated. The catalytic activity in methanol steam reforming was evaluated in a tubular microreactor at atmospheric pressure in the 300-500 degrees C reaction temperature interval (space velocity = 0.32 mol/(h g(cat)) H2O/CH3OH molar ratio = 1.2, methanol concentration 15 mole%). H-2, CO and CO2 were the main reaction products. Methanol conversions up to 72% and H-2 productivities as high as 0.46 mol/(h g(cat)) were obtained on the Pd/CS catalyst. Moreover, low H-2 productivity (0.09 mol/(h g(cat))) was found on the Pd/CeO2 catalyst, while Pd/Sm2O3 appeared to be inactive. This behaviour can be partly assigned to the higher dispersion and the more favourable distribution of Pd particles observed in the Pd/CS catalyst. A strong association of Pd and samarium oxide and an enrichment in both components at the external surface of the Pd/CS catalyst grains was found by means of TPR and XPS. This could be explained by the partial dissolution of Sm2O3 in the acid medium used during catalyst preparation leading to the re-precipitation of a Pd/Sm-containing phase. Higher activity per exposed Pd atom was also observed for the Pd/CS catalyst. This was attributed to enhancement of diffusion and adsorption of reactants on the basic sites of the Sm-containing support. (c) 2005 Elsevier B.V. All rights reserved.
KW - methanol
KW - reforming
KW - hydrogen production
KW - supported palladium catalysts
KW - CeO2
KW - Sm2O3
KW - CeO2-Sm2O3 mixed oxide
KW - anode
KW - solid oxide fuel cells
KW - OXIDE FUEL-CELLS
KW - RARE-EARTH-OXIDES
KW - CERIA-BASED ANODES
KW - HIGH-PERFORMANCE ELECTRODE
KW - OXIDATIVE DIMERIZATION
KW - CHEMICAL-ANALYSIS
KW - CO
KW - DEHYDROGENATION
KW - CHEMISORPTION
KW - SPECTROSCOPY
UR - http://www.scopus.com/inward/record.url?scp=28844477855&partnerID=8YFLogxK
UR - http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6TF5-4H21K7R-3-C&_cdi=5217&_user=1026342&_orig=browse&_coverDate=10%2F10%2F2005&_sk=997059997&view=c&wchp=dGLbVzb-zSkWb&md5=161304eecfe004c790f8795967b020b6&ie=/sdarticle.pdf
U2 - 10.1016/j.apcata.2005.07.022
DO - 10.1016/j.apcata.2005.07.022
M3 - Article
VL - 294
SP - 177
EP - 187
JO - Applied Catalysis. A, General
JF - Applied Catalysis. A, General
IS - 2
ER -