Computational Predictions and Experimental Validation of Alkane Oxidative Dehydrogenation by Fe2M MOF Nodes

Melissa Barona, Sol Ahn, William Morris, William Hoover, Justin M. Notestein*, Omar K. Farha, Randall Q. Snurr

*Corresponding author for this work

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

The modular structure of metal-organic frameworks (MOFs) makes them promising platforms for catalyst design and for elucidating structure/performance relationships in catalysis. In this work, we systematically varied the composition of the metal nodes (Fe2M) of the MOF PCN-250 and used density functional theory (DFT) to identify promising catalysts for light alkane C-H bond activation. Oxidative dehydrogenation (ODH) of alkanes was studied using N2O as the oxidant to understand the reactivity of the oxocentered Fe2M nodes found in PCN-250, where the Fe ions are in the +3 oxidation state and M is a metal with the oxidation state of +2. We show that the N2O activation barrier is positively correlated with the oxygen-binding energy at the metal center, and the C-H activation barrier is negatively correlated with this same quantity. For clusters containing early transition metals, oxygen binds strongly, facilitating N2O activation but hindering C-H activation. To validate the DFT predictions, we synthesized and tested PCN-250(Fe2M) with M = Mn, Fe, Co, and Ni and found that PCN-250(Fe2Mn) and PCN-250(Fe3) are more active than PCN-250(Fe2Co) and PCN-250(Fe2Ni) in agreement with the DFT predictions, demonstrating the power of DFT calculations to predict and identify promising MOF catalysts for alkane C-H bond activation in advance of experiments.

Original languageEnglish (US)
Pages (from-to)1460-1469
Number of pages10
JournalACS Catalysis
Volume10
Issue number2
DOIs
StatePublished - Jan 17 2020

Keywords

  • C-H bond activation
  • PCN-250
  • density functional theory
  • metal-organic frameworks
  • oxidation catalysis
  • oxidative dehydrogenation
  • structure-function relationships

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)

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