Modelling complete methane oxidation over palladium oxide in a porous catalyst using first-principles surface kinetics

2018 ◽  
Vol 8 (2) ◽  
pp. 508-520 ◽  
Author(s):  
Carl-Robert Florén ◽  
Maxime Van den Bossche ◽  
Derek Creaser ◽  
Henrik Grönbeck ◽  
Per-Anders Carlsson ◽  
...  
Keyword(s):  
Methane Oxidation ◽  
First Principles ◽  
Total Pressure ◽  
Reaction Rate ◽  
Palladium Oxide ◽  
Surface Kinetics ◽  
Porous Catalyst

Modeled turnover frequencies for varying temperature and total pressure combined with reaction rate controlling regions.

Hydrogen Recombiner: Theoretical Parametric Study

2002 ◽  
Author(s):  
Gilles Avakian
Keyword(s):  
Hydrogen Concentration ◽  
Total Pressure ◽  
Reaction Rate ◽  
Published Data ◽  
Geometrical Parameters ◽  
Surface Kinetics ◽  
Total Rate ◽  
Diffusion Controlled ◽  
Rate Of Reaction ◽  
Linear Behaviour

There is not yet published data concerning a complete overview of the behaviour of a SIEMENS recombiner versus the thermal hydrualic conditions and the geometry of the catalytic plates. This paper reports on a numerical behaviour of the recombiner depending on several gas parameters as the total pressure, and the hydrogen concentration, as well as geometrical parameters of the catalytic elements as the height and the spacing. We use a theoretical model validated by using the KALI experiments. In this model (Avakian, 1999), the reaction rate is diffusion-controlled, i.e. the contribution of surface kinetics to the total rate of reaction is neglected. We demonstrate a quasi-linear behaviour of the recombination rate vs. the total pressure and the hydrogen concentration. We display the benefit in using smaller catalytic plates instead of taller plates and we give an idea of the influence of the spacing between the catalytic plates.

ACTION OF HIGH SPEED ELECTRONS ON METHANE, OXYGEN AND CARBON MONOXIDE

1930 ◽  
Vol 3 (3) ◽  
pp. 241-251 ◽  
Author(s):  
J. C. McLennan F.R.S. ◽  
J. V. S. Glass B.A.
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Water Vapor ◽  
Formic Acid ◽  
Total Pressure ◽  
High Speed ◽  
Reaction Rate ◽  
First Order ◽  
Gaseous Products ◽  
Retarding Effect

This paper deals with the action of cathode rays on gases and gas mixtures. Methane, methane-oxygen mixtures, carbon monoxide and carbon monoxide-oxygen mixtures were examined. Methane gave small percentages of hydrogen and ethane. Methane and oxygen mixtures gave as gaseous products, carbon monoxide, carbon dioxide and hydrogen, the only other products being water and formic acid. The relative proportions of the products do not vary widely under a wide variation of conditions.The reaction was found to be of the first order with respect to pressure. The reaction rate increases linearly with the voltage up to a certain value, after which it becomes nearly independent of the voltage.The action of cathode rays on carbon monoxide produces carbon dioxide and a solid brown suboxide which is extremely soluble in water, and its composition corresponds to a formula (C3O)n. If the carbon monoxide is moist, no visible amount of solid or liquid is found and there is less carbon dioxide.Carbon monoxide-oxygen mixtures under the action of cathode rays form carbon dioxide. Presence of water vapor has a retarding effect on the reaction. For mixtures of the same composition the reaction rate is proportional to the total pressure. For dry mixtures the product increases with the carbon monoxide present; when moist it is much less, and independent of the carbon monoxide.

scholarly journals Sintering-resistant Pt@CeO2 nanoparticles for high-temperature oxidation catalysis

Nanoscale ◽  
2016 ◽  
Vol 8 (19) ◽  
pp. 10219-10228 ◽  
Author(s):  
Siwon Lee ◽  
Jongsu Seo ◽  
WooChul Jung
Keyword(s):  
High Temperature ◽  
Methane Oxidation ◽  
High Temperature Oxidation ◽  
Reaction Rate ◽  
Ceo2 Nanoparticles ◽  
Oxidation Catalysis ◽  
Core Shell ◽  
Temperature Oxidation

We successfully synthesized shell-controllable Pt@CeO2 core–shell nanocomposites for high-temperature oxidation catalysis. We showed a T10 lower by 100 °C and an eight-fold higher reaction rate compared to a bare mixture of Pt and CeO2 nanoparticles, while maintaining complete methane oxidation for more than 50 h at 700 °C.

Predicting Diffusion Coefficients from First Principles via Eyring’s Reaction Rate Theory

2009 ◽  
Vol 294 ◽  
pp. 1-13 ◽  
Author(s):  
Manjeera Mantina ◽  
Long Qing Chen ◽  
Zi Kui Liu
Keyword(s):  
First Principles ◽  
Diffusion Coefficients ◽  
Reaction Rate ◽  
Harmonic Approximation ◽  
Impurity Diffusion ◽  
Rate Theory ◽  
Simplified Approach ◽  
Self Diffusion ◽  
Reaction Rate Theory ◽  
Jump Frequencies

A simplified approach to predicting diffusion coefficients directly from first-principles is proposed. In this approach, the atomic jump frequencies are calculated through the Eyring’s reaction rate theory while the temperature dependence of diffusion coefficients are accounted using phonon theory within the quasi-harmonic approximation. The procedure can be applied to both self-diffusion and impurity diffusion coefficients and different crystal systems. Applications to self-diffusion coefficients in fcc Cu, bcc Mo, hcp Mg and impurity diffusion coefficients of Li in fcc Al, W in bcc Mo and Cd in hcp Mg show agreement with experimental measurements.

Methane Oxidation over PdO(101) Revealed by First-Principles Kinetic Modeling

2015 ◽  
Vol 137 (37) ◽  
pp. 12035-12044 ◽  
Author(s):  
Maxime Van den Bossche ◽  
Henrik Grönbeck
Keyword(s):  
Methane Oxidation ◽  
Kinetic Modeling ◽  
First Principles

Influence of Reaction Parameters on the First Principles Reaction Rate Modeling of a Platinum and Vanadium Catalyzed Nitro Reduction

2013 ◽  
Vol 17 (10) ◽  
pp. 1277-1286 ◽  
Author(s):  
Brian R. Crump ◽  
Charles Goss ◽  
Tom Lovelace ◽  
Rick Lewis ◽  
John Peterson
Keyword(s):  
First Principles ◽  
Reaction Rate ◽  
Reaction Parameters ◽  
Nitro Reduction
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