CO2 Hydrogenation: Na Doping Promotes CO and Hydrocarbon Formation over Ru/m-ZrO2 at Elevated Pressures in Gas Phase Media

Grant Seuser, Raechel Staffel, Yagmur Hocaoglu, Gabriel F. Upton, Elijah S. Garcia, Donald C. Cronauer, A. Jeremy Kropf, Michela Martinelli, Gary Jacobs

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Sodium-promoted monoclinic zirconia supported ruthenium catalysts were tested for CO2 hydrogenation at 20 bar and a H2:CO2 ratio of 3:1. Although increasing sodium promotion, from 2.5% to 5% by weight, slightly decreased CO2 conversion (14% to 10%), it doubled the selectivity to both CO (~36% to ~71%) and chain growth products (~4% to ~8%) remarkably and reduced the methane selectivity by two-thirds (~60% to ~21%). For CO2 hydrogenation during in situ DRIFTS under atmospheric pressure, it was revealed that Na increases the catalyst basicity and suppresses the reactivity of Ru sites. Higher basicity facilitates CO2 adsorption, weakens the C–H bond of the formate intermediate promoting CO formation, and inhibits methanation occurring on ruthenium nanoparticle surfaces. The suppression of excessive hydrogenation increases the chain growth probability. Decelerated reduction during H2-TPR/TPR-MS and H2-TPR-EXAFS/XANES at the K-edge of ruthenium indicates that sodium is in contact with ruthenium. A comparison of the XANES spectra of unpromoted and Na-promoted catalysts after H2 reduction showed no evidence of a promoting effect involving electron charge transfer.

Original languageEnglish
Article number1155
JournalNanomaterials
Volume13
Issue number7
DOIs
StatePublished - Apr 2023

Bibliographical note

Publisher Copyright:
© 2023 by the authors.

Keywords

  • CO hydrogenation
  • Fischer-Tropsch synthesis
  • monoclinic zirconia
  • reverse water-gas shift
  • ruthenium
  • sodium

ASJC Scopus subject areas

  • General Chemical Engineering
  • General Materials Science

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