title: Effects of adsorbate coverage and bond-length disorder on the d-band center of carbon-supported Pt catalysts.
abstract: Determination of the factors that affect the d-band center of catalysts is required to explain their catalytic properties. Resonant inelastic X-ray scattering (RIXS) enables direct imaging of electronic transitions in the d-band of Pt catalysts in real time and in realistic environmental conditions. Through a combination of in situ, temperature-resolved RIXS measurements and theoretical simulations we isolated and quantified the effects of bond-length disorder and adsorbate coverage (CO and H2) on the d-band center of 1.25 nm size Pt catalysts supported on carbon. We found that the decrease in adsorbate coverage at elevated temperatures is responsible for the d band shifts towards higher energies relative to the Fermi level, whereas the effect of the increase in bond-length disorder on the d-band center is negligible. Although these results were obtained for a specific case of non-interacting support and weak temperature dependence of the metal-metal bond length in a model catalyst, this work can be extended to a broad range of real catalysts.
authors.affiliation: Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews, Urbana, IL 61801 (USA).
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Small
authors.forename: Joshua J
authors.initials: JJ
authors.lastname: Kas
authors.forename: Kristina O
authors.initials: KO
authors.lastname: Kvashnina
authors.forename: John J
authors.initials: JJ
authors.lastname: Rehr
authors.forename: Ralph G
authors.initials: RG
authors.lastname: Nuzzo
authors.forename: Moniek
authors.initials: M
authors.lastname: Tromp
authors.forename: Anatoly I
authors.initials: AI
authors.lastname: Frenkel
keywords: X-ray absorption spectroscopy; catalysis; nanoparticles; platinum; resonant inelastic X-ray scattering