Methanol decomposition over palladium supported mesoporous CeO2–ZrO2 mixed oxides

A CoFe 2 O 4 inverse spinel calcined at two different temperatures (450°C and 750°C), in order to modulate the growth of the crystallites, has been employed in methanol anaerobic oxidation. A correlation between physico-chemical properties and catalytic performances of the material has been pursued. The study of both surface and bulk properties has been carried out by means of different experimental techniques, among which X-ray diffraction (XRD), transmission electron microscopy (TEM), and in situ FTIR spectroscopy. The FTIR study of both bulk and surface spectral features reveals that the calcination step is responsible for the different type of exposed surface sites, and as a consequence, for the different catalytic behaviour. As the use of the spinel as catalyst for methanol transformation into H 2 necessarily implies a regeneration step with steam, in order to recover the oxidative capacity of the solid, both surface and bulk features of the reoxidized solids have been also studied. All results reveal that the two samples, originally morphologically quite different from one another, become very similar after just one redox cycle. Still, it has been also demonstrated that both used materials irreversibly modify their surface properties after the reduction/oxidation process.

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“…In regard to methanol decomposition, different catalysts are active in this reaction [16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

On the Role of Morphology of CoFeO₄ Spinel in Methanol Anaerobic Oxidation

et al. 2012

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“…Their work showed that Cu 0 surface area determines the reaction rate, but indicates ZnO has an important role in the catalyst structure, leading to the choice of Zn as the other primary catalyst component for this study. Ce, Zr, and Pd were selected as promoter materials based on good performance in other published studies [24][25][26][27][28]. So based on the extensive literature on Cu and Cu/Zn, such materials were selected as the primary component of the catalyst library for the methanol reforming reactions because its high activity and reduced tendency for formation of CO.…”

Section: Introductionmentioning

confidence: 99%

Selective Combinatorial Studies on Ce and Zr Promoted Cu/Zn/Pd Catalysts for Hydrogen Productio via Methanol Oxidative Reforming

Schuyten

Wolf

2006

Catal Lett

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The activity and selectivity for partial oxidation of methanol to H 2 and CO 2 on Zr, Ce, promoted Cu/Zn/Pd catalysts, have been studied using a high-throughput method of screening and analysis. In this work, infrared thermography was first used as a descriptor of overall catalytic activity. Then, activity and selectivity of samples with high infrared signal were measured in a flow reactor and characterized by BET, XRD, and XPS. Catalysts promoted with 10% Zr and showed H 2 selectivity >95% with methanol conversion approaching 100% at $200°C.

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“…The difference in shape suggests a decline in pore regularity. The observed phenomena are characteristics of wormhole-like architectures [4,6,[12][13][14][15] . We found that it is especially so in the cases of the EG-removed CZY precursor and the CZY-3 sample (curves 3 and 4 in Figure 3(a)); the latter case may be related to the partial occupancy of NaCl inside the pores of the CZY precursor.…”

Section: Crystal Phase Structurementioning

confidence: 99%

“…Therefore, it is a challenge to develop a strategy for the generation of high-surface-area porous ceria-zirconia solid solutions that is applicable in high-temperature operations. The ceria-zirconia solid solutions reported so far are mostly three-dimensional nanoparticles that were calcined at temperatures lower than 450℃, and porous ceria-zirconia or yttria-zirconia solid solutions are rarely reported [6][7][8] . To our best knowledge, there is no report on the synthesis of porous ceria-zirconia-yttria solid solutions.…”

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confidence: 99%

Synthesis and characterization of wormhole-like mesoporous Ce0.6Zr0.35Y0.05O2 solid solutions

et al. 2007

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Nanoparticles of Ce 0.6 Zr 0.35 Y 0.05 O 2 (CZY) solid solution have been prepared by the CTAB (hexadecyltrimethyl ammonium bromide), CTAB-EG (ethylene glycol) templating, and CTAB-EG-NaCl (in which the pores of the precursor synthesized by the CTAB-EG method is filled by a certain amount of NaCl) method, respectively. The physical properties of these materials were characterized by means of techniques such as X-ray diffraction (XRD), high resolution scanning electron microscopy (HRSEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and N 2 adsorption-desorption measurements. The CZY samples synthesized by the above three methods display wormhole-like mesoporous morphology and cubic crystal structures. The materials are narrow in pore size distribution (averaged pore diameter = 5.3-7.1 nm), high in surface areas (95-119 m 2 /g), and large in pore volumes (0.16-0.18 cm 3 /g). It has been demonstrated that the introduction of NaCl is capable of retaining the pore structures of solid nanomaterials at high-temperature calcination.PHYSICAL CHEMISTRY Ce 0.6 Zr 0.35 Y 0.05 O 2 solid solution, templating synthesis method, wormhole-like mesoporous framework, NaCl filler, rare earth ZrO 2 can be employed as a catalyst or support because it has good isomorphism and surface centers of both acidic and basic nature. Being large in surface area, highly ordered in pore channels, and having surface structures that can be modified easily by chemical means, mesoporous zirconia is superior to its nonporous counterpart [1] in adsorption and catalytic applications. The pore structures of mesoporous zirconia, however, collapse with the removal of surfactants in high-temperature calcination. Despite such deterioration of thermal stability could be hindered through the introduction of a small amount of phosphate or sulfate ions [2] or other cations [3,4] , the added entities exert a negative influence on the catalytic activity, and the modified materials are not suitable to be used as catalysts and supports. In recent years, the ceria-zirconia solid solutions are investigated for the widening of the operation window of three-way catalysts [5] . The results show that the incorporation of a certain amount of ZrO 2 to the CeO 2 lattice can significantly enhance the oxygen storage-release (redox) ability and thermal stability. Although ceriazirconia solid solutions of high surface area have been reported in the literature, most of them were calcined at temperatures below 450℃. It is known that the higher the calcination temperature, the lower is the surface area of the as-received sample. In other words, the materials calcined at low temperatures might not be suitable for catalytic systems that operate at temperatures higher than the temperature adopted for calcination. Therefore, it is a challenge to develop a strategy for the generation of high-surface-area porous ceria-zirconia solid solutions that is applicable in high-temperature operations. The ceria-zirconia solid solutions reported so far are mos...

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Methanol decomposition over palladium supported mesoporous CeO2–ZrO2 mixed oxides

Cited by 60 publications

References 20 publications

On the Role of Morphology of CoFeO₄ Spinel in Methanol Anaerobic Oxidation

On the Role of Morphology of CoFeO₄ Spinel in Methanol Anaerobic Oxidation

Selective Combinatorial Studies on Ce and Zr Promoted Cu/Zn/Pd Catalysts for Hydrogen Productio via Methanol Oxidative Reforming

Synthesis and characterization of wormhole-like mesoporous Ce0.6Zr0.35Y0.05O2 solid solutions

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Methanol decomposition over palladium supported mesoporous CeO2–ZrO2 mixed oxides

Cited by 60 publications

References 20 publications

On the Role of Morphology of CoFeO4 Spinel in Methanol Anaerobic Oxidation

On the Role of Morphology of CoFeO4 Spinel in Methanol Anaerobic Oxidation

Selective Combinatorial Studies on Ce and Zr Promoted Cu/Zn/Pd Catalysts for Hydrogen Productio via Methanol Oxidative Reforming

Synthesis and characterization of wormhole-like mesoporous Ce0.6Zr0.35Y0.05O2 solid solutions

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On the Role of Morphology of CoFeO₄ Spinel in Methanol Anaerobic Oxidation

On the Role of Morphology of CoFeO₄ Spinel in Methanol Anaerobic Oxidation