Influence of Residual Chlorine on Ru/TiO2 Active Sites During CO2 Methanation

James Crawford, Brittney Petel, Mathew Rasmussen, Thomas Ludwig, Elisa Miller, Sawyer Halingstad, Sneha Akhade, Simon Pang, Matthew Yung

Research output: Contribution to journalArticlepeer-review

3 Scopus Citations

Abstract

Titania-supported ruthenium (Ru/TiO2) is an established catalyst for the hydrogenation of carbon dioxide to methane (Sabatier reaction). Chlorine contamination, owed to the RuCl3 precursor, is demonstrated to have a detrimental impact on methanation activity. After calcination and reduction the catalyst contains residual chlorine, shown by XPS. An aqueous ammonia wash removes Cl without leaching Ru. The washed catalysts exhibit improvements in CH4 site-time yields. Low Ru loading catalysts encounter the greatest activity enhancements after washing (∼4.5–fold). DFT calculations indicate that chlorine and CO2 directly compete for adsorption on Ru step sites, with Cl impeding the adsorption of CO2 at under-coordinated sites and at higher Cl coverages. H2-chemisorption/TPR show that Cl removal lowers the onset of low temperature H2 dissociation on Ru. DRIFTS provide evidence that the removal of Cl facilitates low temperature dissociative binding of CO2, indicated by the formation of surface bound linear CO species.

Original languageAmerican English
Article number119292
Number of pages9
JournalApplied Catalysis A: General
Volume663
DOIs
StatePublished - 2023

Bibliographical note

Publisher Copyright:
© 2023 Elsevier B.V.

NREL Publication Number

  • NREL/JA-5100-85305

Keywords

  • CO Utilization
  • Heterogeneous catalysis
  • Methanation
  • Ruthenium
  • Sabatier reaction
  • Titania

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