Surface Alloy or Metal–Cation Interaction-The State of Zn Promoting the Active Cu Sites in Methanol Synthesis Catalysts

Research output: Contribution to journalArticle

Abstract

Model catalysts containing disordered CuO and ZnO species in the pores of SBA-15 were reduced under different conditions (standard: H2, 513 K; severe: CO/H2, 673 K), studied by X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) including operando work and used as catalysts for methanol synthesis at pressures up to 8 bar, where they were comparable with a commercial reference in terms of reaction rates related to Cu surface area. Severe reduction caused significant activation of the Cu sites beyond the sizeable level achieved already after standard reduction. In XRD, which failed to detect most of the active components, owing to small particle sizes, weak indications of alloy formation were found after severe reduction. XAFS, which averages over all species present, showed the interaction of Cu with zinc ions to increase by severe reduction, while formation of Zn0 was below detection limit. On this basis, the promoting interaction of Zn to Cu was ascribed to an interaction of zinc cations with Cu0.

Details

Authors
Organisations
External organisations
  • Ruhr-University Bochum
  • Sasol Germany GmbH
  • ALBA Synchrotron Light Facility
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Chemical Engineering

Keywords

  • catalysis, metal-substrate interaction, methanol synthesis, model catalysts, XAFS
Original languageEnglish
Pages (from-to)365-372
Number of pages8
JournalChemCatChem
Volume9
Issue number2
Publication statusPublished - 2017 Jan 23
Publication categoryResearch
Peer-reviewedYes