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Steady-State CO Oxidation on Pd(111): First-Principles Kinetic Monte Carlo Simulations and Microkinetic Analysis

Piccinin, S; Stamatakis, M; (2017) Steady-State CO Oxidation on Pd(111): First-Principles Kinetic Monte Carlo Simulations and Microkinetic Analysis. Topics in Catalysis , 60 (1-2) pp. 141-151. 10.1007/s11244-016-0725-5. Green open access

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Abstract

Using a kinetic Monte Carlo (KMC) approach with parameters derived from first-principles calculations, we modeled the steady-state of CO oxidation on Pd(111), a prototypical catalytic system with various practical applications, including the treatment of automotive gas exhausts. Focusing on the metallic phase of the catalyst, we studied how the rate of CO oxidation depends on temperature and pressure, at fixed gas phase composition. Comparing the results of our simulations with experimental data, we found that all the qualitative features of this catalytic system are correctly reproduced by our model. We show that, when raising the temperature, the system transitions from a CO-poisoned regime with high apparent activation energy to a regime where the rate is almost independent of the temperature. The almost zero apparent activation energy at high temperature stems from approximately equal and opposite values of the O2 adsorption energy and dissociation barrier, as revealed by a simple microkinetic analysis. In the CO-poisoned regime, the precursor-mediated dissociative adsorption of oxygen plays a crucial role: we find that small changes (within DFT error) in the parameters controlling this elementary step have large effects on the kinetics of CO oxidation at low temperature.

Type: Article
Title: Steady-State CO Oxidation on Pd(111): First-Principles Kinetic Monte Carlo Simulations and Microkinetic Analysis
Open access status: An open access version is available from UCL Discovery
DOI: 10.1007/s11244-016-0725-5
Publisher version: http://dx.doi.org/10.1007/s11244-016-0725-5
Language: English
Additional information: Copyright © Springer Science+Business Media New York 2016. The final publication is available at Springer via http://dx.doi.org/10.1007/s11244-016-0725-5
Keywords: Kinetic Monte Carlo, CO oxidation, Pd(111), DFT
UCL classification: UCL
UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Chemical Engineering
URI: https://discovery.ucl.ac.uk/id/eprint/1519703
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