Nanoscale Chemical Diversity of Coke Deposits on Nanoprinted Metal Catalysts Visualized by Tip-Enhanced Raman Spectroscopy

Matthias Filez*, Peter Walke, Hai Le-The, Shuichi Toyouchi, Wannes Peeters, Patrick Tomkins, Jan C.T. Eijkel, Steven De Feyter, Christophe Detavernier, Dirk E. De Vos, Hiroshi Uji-I, Maarten B.J. Roeffaers*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

6 Citations (Scopus)
104 Downloads (Pure)

Abstract

Coke formation is the prime cause of catalyst deactivation, where undesired carbon wastes block the catalyst surface and hinder further reaction in a broad gamut of industrial chemical processes. Yet, the origins of coke formation and their distribution across the catalyst remain elusive, obstructing the design of coke-resistant catalysts. Here, the first-time application of tip-enhanced Raman spectroscopy (TERS) is demonstrated as a nanoscale chemical probe to localize and identify coke deposits on a post-mortem metal nanocatalyst. Monitoring coke at the nanoscale circumvents bulk averaging and reveals the local nature of coke with unmatched detail. The nature of coke is chemically diverse and ranges from nanocrystalline graphite to disordered and polymeric coke, even on a single nanoscale location of a top-down nanoprinted SiO2-supported Pt catalyst. Surprisingly, not all Pt is an equal producer of coke, where clear isolated coke “hotspots” are present non-homogeneously on Pt which generate large amounts of disordered coke. After their formation, coke shifts to the support and undergoes long-range transport on the surrounding SiO2 surface, where it becomes more graphitic. The presented results provide novel guidelines to selectively free-up the coked metal surface at more mild rejuvenation conditions, thus securing the long-term catalyst stability.

Original languageEnglish
Article number2305984
Number of pages8
JournalAdvanced materials
Volume36
Issue number5
Early online date8 Nov 2023
DOIs
Publication statusPublished - 1 Feb 2024

Keywords

  • 2024 OA procedure
  • coke formation
  • nanoparticle catalysts
  • propane dehydrogenation
  • reactivation
  • tailored catalyst fabrication
  • tip-enhanced Raman spectroscopy

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