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A review of catalytic partial oxidation of methane to synthesis gas with emphasis on reaction mechanisms over transition metal catalysts
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In this article, an extensive table on contributions to catalytic partial oxidation of methane over transition metal catalysts in the literature is provided, and both theoretical and experimental evidence pointing to inherent differences in the reaction mechanism over transition metals.Abstract:
Catalytic partial oxidation of methane has been reviewed with an emphasis on the reaction mechanisms over transition metal catalysts. The thermodynamics and aspects related to heat and mass transport is also evaluated, and an extensive table on research contributions to methane partial oxidation over transition metal catalysts in the literature is provided. Presented are both theoretical and experimental evidence pointing to inherent differences in the reaction mechanism over transition metals. These differences are related to methane dissociation, binding site preferences, the stability of OH surface species, surface residence times of active species and contributions from lattice oxygen atoms and support species. Methane dissociation requires a reduced metal surface, but at elevated temperatures oxides of active species may be reduced by direct interaction with methane or from the reaction with H, H2, C or CO. The comparison of elementary reaction steps on Pt and Rh illustrates that a key factor to produce hydrogen as a primary product is a high activation energy barrier to the formation of OH. Another essential property for the formation of H2 and CO as primary products is a low surface coverage of intermediates, such that the probability of O–H, OH–H and CO–O interactions are reduced. The local concentrations of reactants and products change rapidly through the catalyst bed. This influences the reaction mechanisms, but the product composition is typically close to equilibrated at the bed exit temperature.read more
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Ni-based bimetallic heterogeneous catalysts for energy and environmental applications
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Journal ArticleDOI
Methane Activation by Heterogeneous Catalysis
Raimund Horn,Robert Schlögl +1 more
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The Direct Catalytic Oxidation of Methane to Methanol-A Critical Assessment.
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Hydrogen: A brief overview on its sources, production and environmental impact
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O2 Activation by Metal Surfaces: Implications for Bonding and Reactivity on Heterogeneous Catalysts
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References
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Journal ArticleDOI
Optimization of autothermal reactor for maximum hydrogen production
TL;DR: In this paper, a framework for theoretical interpretation of reforming reactions is developed using an atomic balance approach, which is utilized to determine the reforming reaction space and maximum monolith temperature for a methane reformer.
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Distinct spatial changes of the catalyst structure inside a fixed-bed microreactor during the partial oxidation of methane over Rh/Al2O3
Stefan Hannemann,Jan-Dierk Grunwaldt,Niels van Vegten,Alfons Baiker,P. Boye,Christian G. Schroer +5 more
TL;DR: In this article, an X-ray image of the R 2 O 3 (Rh) was used to determine the structural changes of the catalyst in a micro-reactor with a fixed-bed of 2.5 Wt% Rh/Al O 3.
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Partial oxidation of CH4 and C2H6 over noble metalcoated monoliths
Lanny D. Schmidt,Marylin C. Huff +1 more
TL;DR: In this article, the authors describe experiments in which monolith catalysts are used for partial oxidation of CH4 and C2H6 to produce synthesis gas or alkenes by direct oxidation at or above atmospheric pressure in pure O2 in nearly adiabatic reactors operating at 1000°C with very high flow rates.
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Partial oxidation of methane to synthesis gas over supported iridium catalysts
TL;DR: In this paper, the performance of supported iridium catalysts in synthesis gas formation depended strongly on the support materials, and the active species of iridium was found to be metallic iridium by XPS analyses.
Journal ArticleDOI
Mechanistic study of partial oxidation of methane to synthesis gas over supported rhodium and ruthenium catalysts using in situ time-resolved FTIR spectroscopy
TL;DR: In situ time-resolved FTIR spectroscopy was used to study the reaction mechanism of partial oxidation of methane to synthesis gas and the interaction of CH 4 /O 2 /He (2/1/45) gas mixture with adsorbed CO species over SiO 2 and γ-Al 2 O 3 supported Rh and Ru catalysts at 500-600°C.