First principles calculations and experimental insight into methane steam reforming over transition metal catalysts

Jones, Glenn; Jakobsen, J.; Shim, Signe S.; Kleis, Jesper; Andersson, Martin; Rossmeisl, Jan; Abild‐Pedersen, Frank; Bligaard, Thomas; Helveg, Stig; Hinnemann, Berit; Rostrup-Nielsen, J.R.; Chorkendorff, Ib; Sehested, Jens; Nørskov, Jens K.

doi:10.1016/j.jcat.2008.08.003

Cited by 564 publications

(405 citation statements)

References 56 publications

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“…TOF values increased linearly with dispersion indicating a structure sensitive reaction with stepped sites being more active than terrace sites. Jones et al [19] also reported an elementary step mechanism for steam reforming on these metals and concluced that CO formation [20].…”

Section: Steam Reformingmentioning

confidence: 95%

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Methane Activation by Heterogeneous Catalysis

2014

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Methane activation by heterogeneous catalysis will play a key role to secure the supply of energy, chemicals and fuels in the future. Methane is the main constituent of natural gas and biogas and it is also found in crystalline hydrates at the continental slopes of many oceans and in permafrost areas. In view of this vast reserves and resources, the use of methane as chemical feedstock has to be intensified. The present review presents recent results and developments in heterogeneous catalytic methane conversion to synthesis gas, hydrogen cyanide, ethylene, methanol, formaldehyde, methyl chloride, methyl bromide and aromatics. After presenting recent estimates of methane reserves and resources the physico-chemical challenges of methane activation are discussed. Subsequent to this recent results in methane conversion to synthesis gas by steam reforming, dry reforming, autothermal reforming and catalytic partial oxidation are presented. The high temperature methane conversion to hydrogen cyanide via the BMA-process and the Andrussow-process is considered as well. The second part of this review focuses on one-step conversion of methane into chemicals. This includes the oxidative coupling of methane to ethylene mediated by oxygen and sulfur, the direct oxidation of methane to formaldehyde and methanol, the halogenation and oxyhalogenation of methane to methyl chloride and methyl bromide and finally the non-oxidative methane aromatization to benzene and related aromates. Opportunities and limits of the various activation strategies are discussed.

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Section: Steam Reformingmentioning

confidence: 95%

“…By combining DFT calculations, scaling relations and microkinetic modeling, Jones et al [19] were able to calculate a 2D-volcano plot showing the turn over frequency as function of the O Ã and C Ã adsorption energies (Fig. 1).…”

Section: Steam Reformingmentioning

confidence: 99%

Methane Activation by Heterogeneous Catalysis

2014

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“…The dissociation (or dissociative chemisorption) of CH 4 on the catalyst into CH 3 (ad) + H(ad) is a rate-determining step of the full process. 1 Moreover, dissociation of methane on metal surfaces is of fundamental interest. 2−13 Already from early molecular beam experiments, it is known that vibration is very effective in promoting reactivity.…”

mentioning

confidence: 99%

“…35 An accurate value of E b is also relevant to accurately modeling the steam reforming reaction over a Pt(111) surface as kinetics calculations of rates of heterogeneously catalyzed processes require reaction barrier heights as input parameters. 1 Within the appropriate level of dynamical theory and if an accurate PES is available, dynamics calculations can in principle solve all of the above problems and yield a consistently accurate description of all experiments described above. Dynamics calculations and their comparison to supersonic molecular beam experiments directly test whether the PES contains an accurate description of E b and of the couplings of the molecule's and surface atoms' vibrations to the reaction coordinate.…”

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confidence: 99%

Ab Initio Molecular Dynamics Calculations versus Quantum-State-Resolved Experiments on CHD₃ + Pt(111): New Insights into a Prototypical Gas–Surface Reaction

Nattino

Ueta

Chadwick

et al. 2014

J. Phys. Chem. Lett.

122

198

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ABSTRACT:The dissociative chemisorption of methane on metal surfaces is of fundamental and practical interest, being a rate-limiting step in the steam reforming process. The reaction is best modeled with quantum dynamics calculations, but these are currently not guaranteed to produce accurate results because they rely on potential energy surfaces based on untested density functionals and on untested dynamical approximations. To help overcome these limitations, here we present for the first time statistically accurate reaction probabilities obtained with ab initio molecular dynamics (AIMD) for a polyatomic gas-phase molecule reacting with a metal surface. Using a general purpose density functional, the AIMD reaction probabilities are in semiquantitative agreement with new quantum-state-resolved experiments on CHD 3 + Pt(111). The comparison suggests the use of the sudden approximation for treating the rotations even though CHD 3 has large rotational constants and yields an estimated reaction barrier of 0.9 eV for CH 4 + Pt(111). SECTION: Surfaces, Interfaces, Porous Materials, and Catalysis T he steam reforming process, in which methane and water react over a Ni catalyst, is the main commercial source of molecular hydrogen. The dissociation (or dissociative chemisorption) of CH 4 on the catalyst into CH 3 (ad) + H(ad) is a rate-determining step of the full process. 1 Moreover, dissociation of methane on metal surfaces is of fundamental interest. 2−13 Already from early molecular beam experiments, it is known that vibration is very effective in promoting reactivity. 3,4,14 More recently, it has been shown that the reaction is mode-specific, that is, the degree to which energizing the molecule promotes reaction depends on whether the energy is put in translation or vibration and even on which vibration it is put in (vibrational mode specificity). 5−8 These observations, which have been explained qualitatively on the basis of different models, 9,15 rule out the application of fully statistical models. For some vibrational modes, the vibrational efficacy, which measures how effective putting energy into vibration is at promoting reaction relative to increasing the incidence energy (E i ), is even larger than one. 7,10 In addition, the dissociation of partially deuterated molecules shows bond selectivity; for instance, in CHD 3 , the CH bond can be selectively broken upon excitation to an appropriate initial vibrational state. 11,12 Finally, dissociative chemisorption of methane on metal surfaces represents a current frontier in the theoretical description of the dynamics of reactions of gas-phase molecules on metal surfaces, 15−24 with much current efforts now being aimed at achieving an accurate description of this reaction through high-dimensional quantum dynamics calculations. 16,23,24 A wealth of experiments exist for the methane + Pt(111) system. 3,8,12,17,25−29 There has been considerable debate 2,25 concerning the importance of tunneling in this and similar systems. Recent calculations 17,23,30 suggest only a...

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“…The data will be part of a larger database of surface reaction data that are being developed under the Quantum Materials Informatics Project, see ref. [17][18][19][20][21][22] where the details of the calculations can be found. The important point here is that they have all been calculated with the same code (DACAPO), the same exchange-correlation energy functional (GGA-RPBE), [23] and similar calculational parameters.…”

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confidence: 99%

CatApp: A Web Application for Surface Chemistry and Heterogeneous Catalysis

et al. 2011

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We introduce a web application (CatApp) for looking up calculated reaction and activation energies for elementary coupling reactions occurring on metal surfaces. It provides access to reaction and activation energies for all reactions involving C-C, C-H, C-O, O-O, O-H, N-N, C-N, O-N, N-H splittingSolid catalysts form the backbone of the chemical industry and the hydrocarbon-based energy sector. Most catalysts and processes today are highly optimized, but there is still considerable room for improvements in reactivity and selectivity that would lower energy consumption and waste production. In addition there are tremendous challenges to catalysis science and engineering in developing a sustainable energy solutions. The ability to store solar energy as a fuel calls for new catalysts and so does the development of a sustainable chemical industry based on biomass and other non-fossil building blocks.The development of new catalysts could be accelerated significantly if we had access to systematic data for activation energies of elementary surface reactions. Once the key parameters determining the activity or selectivity of a certain process has been established though experiments or calculations, such a database would enable searches for new catalyst leads. Ideally, data would come from detailed, systematic experiments, but it is in general not possible to find such data. Electronic structure calculations provide a powerful alternative. The accuracy is not such that detailed predictions of absolute rates of elementary reaction steps can be made, but for classes of interesting catalysts (transition metals) it is possible to create systematic data with sufficient accuracy to predict trends in reactivity. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] In the present paper, we introduce such a set of calculated reaction energies and activation energies for a large number of elementary surface reactions on a series of metal single crystal surfaces including surfaces with defects such as steps. We will also introduce a simple web application (CatApp) that can be downloaded to access these data.

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First principles calculations and experimental insight into methane steam reforming over transition metal catalysts

Cited by 564 publications

References 56 publications

Methane Activation by Heterogeneous Catalysis

Methane Activation by Heterogeneous Catalysis

Ab Initio Molecular Dynamics Calculations versus Quantum-State-Resolved Experiments on CHD₃ + Pt(111): New Insights into a Prototypical Gas–Surface Reaction

CatApp: A Web Application for Surface Chemistry and Heterogeneous Catalysis

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First principles calculations and experimental insight into methane steam reforming over transition metal catalysts

Cited by 564 publications

References 56 publications

Methane Activation by Heterogeneous Catalysis

Methane Activation by Heterogeneous Catalysis

Ab Initio Molecular Dynamics Calculations versus Quantum-State-Resolved Experiments on CHD3 + Pt(111): New Insights into a Prototypical Gas–Surface Reaction

CatApp: A Web Application for Surface Chemistry and Heterogeneous Catalysis

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Ab Initio Molecular Dynamics Calculations versus Quantum-State-Resolved Experiments on CHD₃ + Pt(111): New Insights into a Prototypical Gas–Surface Reaction