Catalytic dehydrogenation of isobutane over supported MoOx/K-Al2O3

Emily Cheng, Justin Notestein*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Potassium-promoted, alumina-supported molybdenum oxide is investigated for non-oxidative isobutane dehydrogenation, with an emphasis on sub-monolayer coverages. After pre-reduction in H2, initial isobutene turnover frequencies are largely independent of Mo loading, but deactivation rate constants increase by >100-fold as loadings increase to monolayer, leading to a >13-fold difference in reaction rates at extended time on stream. Mo oxidation state by in situ X-ray absorption spectroscopy is stable with time on stream, arguing against continued catalyst restructuring as the origin of deactivation. Across the set of loadings, isobutane dehydrogenation and coke formation are correlated with partially reduced Mo4+ and deeply reduced Moδ+ sites, respectively. Given the stable dehydrogenation activity of low-loaded Mo, in contrast to the rapid deactivation of high-loaded Mo, sub-monolayer metal oxides may warrant further investigation as light alkane dehydrogenation even when their bulk counterparts may not.

Original languageEnglish (US)
Pages (from-to)212-222
Number of pages11
JournalJournal of Catalysis
Volume397
DOIs
StatePublished - May 2021

Keywords

  • Dehydrogenation
  • Isobutane
  • Metal oxides
  • Molybdenum oxide
  • Sub-monolayer MoO

ASJC Scopus subject areas

  • Catalysis
  • Physical and Theoretical Chemistry

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