Steam reforming of methanol over Cu/ZrO2. Role of ZrO2 support

Takezawa, Nobutsune; Shimokawabe, Masahide; Hiramatsu, Hiromi; Sugiura, Hiroaki; Asakawa, Tomohiro; Kobayashi, Haruo

doi:10.1007/bf02066722

Cited by 50 publications

(22 citation statements)

References 6 publications

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“…of dispersion differ somewhat from previous conclusions that reforming rates are independent of dispersion for Cu/ZrO 2 (0.05-0.43 Cu dispersion), 39 although the clusters size effects that we report here are indeed weak. Cluster size effects that favor C-H bond activation on small clusters for reforming of ethanol on CuNiK/γ-Al 2 O 3 (3-5 nm clusters) 40 and of CH 4 on Rh, 41 Ru, 42 Pt, 43 Ir, 44 and Ni 45 clusters are consistent with our finding here for methanol reforming on Cu.…”

Section: 4contrasting

confidence: 99%

Isotopic and Kinetic Assessment of the Mechanism of CH₃OH−H₂O Catalysis on Supported Copper Clusters

Kim

Iglesia

2008

J. Phys. Chem. C

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This study provides kinetic and isotopic evidence for the identity and kinetic relevance of elementary steps in CH 3 OH-H 2 O reactions on monofunctional Cu-based catalysts. H 2 , CO 2 , and CO were the only products formed in these reactions, which proceed via kinetically relevant C-H bond activation in chemisorbed methoxides. All other elementary steps are in quasi-equilibrium, consistent with the effects of reactants and products on rates, with isotopic tracing and kinetic isotope evidence, and with the equilibrated nature of water gas shift reactions at all reaction conditions. Turnover rates increased with CH 3 OH pressure but did not depend on CO, CO 2 , or H 2 O concentrations. H 2 inhibited CH 3 OH-H 2 O reactions by decreasing the concentration of surface methoxide intermediates via quasi-equilibrated CH 3 OH dissociation steps. Isotopic scrambling was complete among hydroxyl groups in methanol and water, but undetectable among hydroxyl and methyl groups in methanol, consistent with quasi-equilibrated O-H activation and irreversible C-H activation steps. Deuterium substitution at methyl groups in methanol gave normal kinetic isotope effects, whereas substitution at hydroxyl groups in methanol or water led to weaker isotope effects consistent with their thermodynamic origin from quasi-equilibrated O-H activation steps. These mechanistic conclusions are consistent with detailed kinetic data on both large and small Cu clusters and with reforming pathways requiring only Cu surfaces to complete catalytic turnovers. CH 3 OH-H 2 O turnover rates increased weakly with Cu dispersion as Cu cluster size decreased from 30 to 5 nm, suggesting that these reactions are insensitive to structure when CH 3 OH-H 2 O reaction occurs on Cu via monofunctional pathways limited by H-abstraction from methoxide intermediates. This structure insensitivity may reflect the titration of low-coordination surfaces with strongly held and unreactive forms of adsorbed intermediates, causing turnovers to occur preferentially on low-index surfaces for clusters of varying size.

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Section: 4contrasting

confidence: 99%

Isotopic and Kinetic Assessment of the Mechanism of CH₃OH−H₂O Catalysis on Supported Copper Clusters

Kim

Iglesia

2008

J. Phys. Chem. C

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“…A clear decrease in reduction temperature by decreasing particle size (e.g. [21]) was not found. Particles of samples #2-4 grew only by a factor of G = 1.5-2.3 without recognisable tendencies (100-150 nm).…”

Section: Reduction Experimentsmentioning

confidence: 59%

“…Aluminum oxide [18], silicium oxide [19], titanium oxide [20] and zirconium oxide [21] are the most famous carrier materials. Zinc oxide is well known to promote the copper [22] in functionality, possibly by the so called spill-over effect [23].…”

Section: Introductionmentioning

confidence: 99%

Preparation of copper catalyst washcoats for methanol steam reforming in microchannels based on nanoparticles

Pfeifer¹,

Schubert²,

Emig³

2005

Applied Catalysis A: General

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“…Recently, the sales of biodiesel in US has reached 75 million gallon (Takezawa et al 1987). This interest stems from the fact that biodiesel is renewable, domestically produced and reduce some pollutants emissions and also have beneficial impacts on engine emissions.…”

Section: Environmental Considerationsmentioning

confidence: 98%

Environmental aspects of biofuels in road transportation

2008

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Steam reforming of methanol over Cu/ZrO2. Role of ZrO2 support

Cited by 50 publications

References 6 publications

Isotopic and Kinetic Assessment of the Mechanism of CH₃OH−H₂O Catalysis on Supported Copper Clusters

Isotopic and Kinetic Assessment of the Mechanism of CH₃OH−H₂O Catalysis on Supported Copper Clusters

Preparation of copper catalyst washcoats for methanol steam reforming in microchannels based on nanoparticles

Environmental aspects of biofuels in road transportation

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Steam reforming of methanol over Cu/ZrO2. Role of ZrO2 support

Cited by 50 publications

References 6 publications

Isotopic and Kinetic Assessment of the Mechanism of CH3OH−H2O Catalysis on Supported Copper Clusters

Isotopic and Kinetic Assessment of the Mechanism of CH3OH−H2O Catalysis on Supported Copper Clusters

Preparation of copper catalyst washcoats for methanol steam reforming in microchannels based on nanoparticles

Environmental aspects of biofuels in road transportation

Contact Info

Product

Resources

About

Isotopic and Kinetic Assessment of the Mechanism of CH₃OH−H₂O Catalysis on Supported Copper Clusters

Isotopic and Kinetic Assessment of the Mechanism of CH₃OH−H₂O Catalysis on Supported Copper Clusters