Catalytic activation and reforming of methane on supported palladium clusters

Yamaguchi, Aritomo; Iglesia, Enrique

doi:10.1016/j.jcat.2010.06.001

Cited by 105 publications

(87 citation statements)

References 33 publications

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“…This fact suggests that the reforming is a structure-sensitive reaction. This general trend is applicable for all of the group VIII metal catalysts 20) and, rather surprisingly, activities among different metals were very similar, as shown in Fig. 1.…”

Section: Mechanistic Aspects Of the Catalytic Co2supporting

confidence: 67%

“…1. The first C _ H bond activation step is irreversible on all metals except Pd, where the rate constant for C _ H bond dissociation was one order of magnitude higher than those for other metals 20) . The rate was inhibited by H2 and CO products only in the case of the Pd catalyst, unlike other metals, where no inhibition effects were observed.…”

Section: Mechanistic Aspects Of the Catalytic Co2mentioning

confidence: 85%

“…It is also interesting to note that the activity difference for different particle sizes is not drastic for any of the metal catalysts 20) . For comparison, the rates of ammonia synthesis are easily altered by several orders of magnitude using different particle sizes of Ru, where the kinetically relevant N2 activation predominantly occurs on B5 sites 22) .…”

Section: Mechanistic Aspects Of the Catalytic Co2mentioning

confidence: 97%

“…The reforming reaction proceeds with the kinetically relevant C _ H bond activation in CH4 followed by the rapid oxidation of the remaining carbon species on the metal surfaces 17) . Zero-order kinetics in the CO2 or H2O coreactants suggest that the carbon originating from CH4 will be immediately oxidized by the species derived from CO2 and H2O, which does not occupy the active sites for CH4 dissociation 20) . The product distribution is determined based on the water-gas shift equilibrium (Reaction (3)) 20) .…”

Section: Mechanistic Aspects Of the Catalytic Co2mentioning

confidence: 99%

“…Zero-order kinetics in the CO2 or H2O coreactants suggest that the carbon originating from CH4 will be immediately oxidized by the species derived from CO2 and H2O, which does not occupy the active sites for CH4 dissociation 20) . The product distribution is determined based on the water-gas shift equilibrium (Reaction (3)) 20) . The apparent activation energy is measured to be ~100 kJ・mol -1 on nickel surfaces 21) .…”

Section: Mechanistic Aspects Of the Catalytic Co2mentioning

confidence: 99%

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Catalytic Conversion of Methane: Carbon Dioxide Reforming and Oxidative Coupling

Takanabe

2012

J. Jpn. Petrol. Inst.

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Natural gas conversion remains one of the essential technologies for current energy needs. This review focuses on the mechanistic aspects of the development of efficient and durable catalysts for two reactions, carbon dioxide reforming and the oxidative coupling of methane. These two reactions have tremendous technological significance for practical application in industry. An understanding of the fundamental aspects and reaction mechanisms of the catalytic reactions reviewed in this study would support the design of industrial catalysts. CO2 reforming of methane utilizes CO2, which is often stored in large quantities, to convert as a reactant. Strategies to eliminate carbon deposition, which is the major problem associated with this reaction, are discussed. The oxidative coupling of methane directly produces ethylene in one reactor through a slightly exothermic reaction, potentially minimizing the capital cost of the natural gas conversion process. The focus of discussion in this review will be on the attainable yield of C2 products by rigorous kinetic analyses.

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Section: Mechanistic Aspects Of the Catalytic Co2supporting

confidence: 67%

Section: Mechanistic Aspects Of the Catalytic Co2mentioning

confidence: 85%

Section: Mechanistic Aspects Of the Catalytic Co2mentioning

confidence: 97%

Section: Mechanistic Aspects Of the Catalytic Co2mentioning

confidence: 99%

Section: Mechanistic Aspects Of the Catalytic Co2mentioning

confidence: 99%

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Catalytic Conversion of Methane: Carbon Dioxide Reforming and Oxidative Coupling

Takanabe

2012

J. Jpn. Petrol. Inst.

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Production of Renewable Hydrogen by Reformation of Biofuels

Panagiotopoulou¹,

Papadopoulou²,

Matralis³

et al. 2015

Advances in Bioenergy

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The Active Phase of Nickel/Ordered Ce₂Zr₂O_x Catalysts with a Discontinuity (x=7–8) in Methane Steam Reforming

et al. 2012

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In recent years, there has been a surge in interest in syngas (H 2 /CO) and H 2 production technologies, which utilize a wide variety of hydrocarbon feed stocks, such as gasoline, diesel, LPG, natural gas, methanol, and bio-ethanol. Among fossil fuels, natural gas (! 90 vol % CH 4 ) is the ideal fuel, owing to its ready availability, high energy density, and wide distribution network; CH 4 activation and reforming provide attractive ways to produce syngas, which can be transformed to useful larger hydrocarbons. Catalysts based on both noble metals and other metals have been extensively studied for CH 4 steam reforming. [1,2] Noble-metal (Rh, Ru, Ir, Pd, and Pt) catalysts are active and stable; however, because of the limited supply and high cost of noble metals, much attention has been paid to the development of non-noble metal catalysts, among which nickel-based catalysts have attracted particular attention because of their similar mechanistic features to noble-metal catalysts. [3] The strong C À H bonds of CH 4 (439 kJ mol À1 ) [4] and endothermic heat of reforming reactions necessitate high temperatures for practical CH 4 conversion, and thus stable catalysts that resist sintering under extreme operating conditions. In CH 4 steam reforming, coke formation that deactivates the catalyst is thermodynamically favored at a H 2 O/CH 4 ratio less than 1.4. Thus, industrial CH 4 steam reforming is usually carried out at a H 2 O/CH 4 ratio of 1.4 or greater. [5] Although catalytic CH 4 steam reforming at low H 2 O/CH 4 ratios have many advantages from operational and energy-consuming viewpoints, conventional nickel-based catalysts suffer from severe carbon deposition under such conditions. Supports and additives (for example, CeO 2 , ZrO 2 , CeO 2 -ZrO 2 , and La 2 O 3 ) have been used to confer catalysts with kinetic resistance to carbon deposition and Ni sintering because they enhance redox activity and thermal stability, thereby promoting steam reforming. [6] The efficient CH 4 upgrading has long been a challenge in fundamental research. [7] Herein, we report the unique properties and active phase of a new Ni/ordered Ce 2 Zr 2 O x (x = 7-8) catalyst with a regular arrangement of Ce and Zr ions in CH 4 steam reforming to produce H 2 and CO at H 2 O/CH 4 = 1. The catalytic performance of Ni/Ce 2 Zr 2 O x (x = 7-8) strongly depends on the phase and oxygen content of Ce 2 Zr 2 O x , and it shows a unique discontinuity in catalytic activity at x = 7.5.The 2 wt % Ni/pyrochlore-Ce 2 Zr 2 O 7 catalyst showed a remarkable performance in CH 4 steam reforming at 923 K at H 2 O/CH 4 = 1 (Table 1). Ni/CeO 2 , Ni/ZrO 2 , and Ni/CeO 2 -ZrO 2 reduced by H 2 were much less active and selective than Ni/Ce 2 Zr 2 O 7 , and significant deactivation was observed probably owing to Ni sintering and carbon deposition. On the other hand, the Ni/pyrochlore-Ce 2 Zr 2 O 7 catalyst was stable, resulting in a remarkably high catalytic performance (for a typical 50 h performance, see the Supporting Information, Figure S4). At 973 K, the Ni/Ce 2 Z...

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Catalytic activation and reforming of methane on supported palladium clusters

Cited by 105 publications

References 33 publications

Catalytic Conversion of Methane: Carbon Dioxide Reforming and Oxidative Coupling

Catalytic Conversion of Methane: Carbon Dioxide Reforming and Oxidative Coupling

Production of Renewable Hydrogen by Reformation of Biofuels

The Active Phase of Nickel/Ordered Ce₂Zr₂O_x Catalysts with a Discontinuity (x=7–8) in Methane Steam Reforming

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Catalytic activation and reforming of methane on supported palladium clusters

Cited by 105 publications

References 33 publications

Catalytic Conversion of Methane: Carbon Dioxide Reforming and Oxidative Coupling

Catalytic Conversion of Methane: Carbon Dioxide Reforming and Oxidative Coupling

Production of Renewable Hydrogen by Reformation of Biofuels

The Active Phase of Nickel/Ordered Ce2Zr2Ox Catalysts with a Discontinuity (x=7–8) in Methane Steam Reforming

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The Active Phase of Nickel/Ordered Ce₂Zr₂O_x Catalysts with a Discontinuity (x=7–8) in Methane Steam Reforming