Substrate Effect of Ir and Rh on Surface ReOxSpecies under a Hydrogen Atmosphere Studied by NAP-XPS

Jiatang Chen, Jumpei Kawai, Kosei Ozawa, Ryo Toyoshima, Keiichi Tomishige, Hiroshi Kondoh

Research output: Contribution to journalArticlepeer-review

Abstract

The substrate effect of M-Re (M is a noble metal) bifunctional catalysts for C-O hydrogenolysis has been studied by using single-crystal substrates including Ir(111) and Rh(111) with in situ near-ambient-pressure X-ray photoelectron spectroscopy (NAP-XPS). Compared with Ir-Re and Rh-Re nanoparticle systems reported in the literature, the single crystals Ir(111) and Rh(111) have shown a more significant substrate effect in determining the surface Re species under a H2 atmosphere at elevated temperatures. It has been found that the hydrogen dissociation and spillover efficiency as the intrinsic property of the noble metals significantly impacts the surface species. A surface that supplies hydrogen more efficiently results in a lower overall oxidation state of Re. Most importantly, the chemical environment of OH species is also closely related to the hydrogen spillover; that is, the more efficient hydrogen spillover, the lower is the oxidation state of Re(-OH). Because the Re-OH sites are commonly considered as the active sites for terminal binding of the reactant molecules, the noble-metal substrates are expected to impact the binding strength of the adsorbate species and hence the overall catalytic activity by tuning the acidity of the Re-OH sites.

Original languageEnglish
Pages (from-to)11544-11552
Number of pages9
JournalJournal of Physical Chemistry C
Volume126
Issue number28
DOIs
Publication statusPublished - 2022 Jul 21

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

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