Electro-Oxidation of Methane on Platinum under Ambient Conditions

Michael J. Boyd, Allegra A. Latimer, Colin F. Dickens, Adam C. Nielander, Christopher Hahn, Jens K. Nørskov*, Drew C. Higgins, Thomas F. Jaramillo

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Herein, we investigate the electrochemical conversion of methane to CO2 on platinum electrodes under ambient conditions. Through a combination of experimentation, density functional theory (DFT) calculations, and ab initio kinetic modeling, we have developed an improved understanding of the reaction mechanism and the factors that determine catalyst activity. We hypothesized that the rate-determining methane activation step is thermochemical (i.e., CH4(g) → CH3 + H) as opposed to electrochemical based on a fitted barrier of approximately 0.96 eV that possesses minimal potential dependence. We developed a simple kinetic model based on the assumption of thermochemical methane activation as the rate-determining step, and the results match well with experimental data. Namely, the magnitude of the maximum current density and the electrode potential at which it is realized agree with our ab initio kinetic model. Finally, we expanded our kinetic model to include other transition metals via a descriptor-based analysis and found platinum to be the most active catalyst for the oxidation of methane, which is in line with previously published experimental observations.

Original languageEnglish
JournalACS Catalysis
Volume9
Issue number8
Pages (from-to)7578-7587
Number of pages10
ISSN2155-5435
DOIs
Publication statusPublished - 2019

Keywords

  • DFT
  • Electro-oxidation
  • Kinetic modeling
  • Methane
  • Platinum

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