The Role of Sodium in Tuning Product Distribution in Syngas Conversion by Rh Catalysts

Nuoya Yang, Xinyan Liu, Arun S. Asundi, Jens K. Nørskov, Stacey F. Bent*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Abstract: Alkali metal oxides commonly exist as impurities or promoters in syngas conversion catalysts and can significantly influence the activity and selectivity towards higher oxygenate products. In this study, we investigate the effects of sodium oxide on silica-supported Rh catalysts by experimentally introducing different amounts of sodium and monitoring the change in reactivity and CO adsorption behavior. The experimental results combined with density functional theory (DFT) calculations show that sodium selectively blocks step/defect sites on Rh surfaces, leading to reduced activity but higher C2 oxygenate selectivity. DFT calculations also suggest that sodium present on Rh terrace sites can facilitate CO dissociation, potentially increasing C2 oxygenate production. The overall activity and selectivity toward various products can be changed significantly based on the degree of site blocking by the added sodium. 

Original languageEnglish
JournalCATALYSIS LETTERS
Volume148
Issue number1
Pages (from-to)289-297
ISSN1011-372X
DOIs
Publication statusPublished - 2018
Externally publishedYes

Keywords

  • Alkali impurity
  • Alkali promoter
  • Higher oxygenates synthesis
  • Rh catalyst
  • Syngas conversion

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