Pressure-Dependent Effect of Hydrogen Adsorption on Structural and Electronic Properties of Pt/gamma-Al2O3 Nanoparticles

    Authors

    H. Mistry; F. Behafarid; S. R. Bare;B. R. Cuenya

    Comments

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    Abbreviated Journal Title

    ChemCatChem

    Keywords

    hydrogen; nanoparticles; platinum; structure elucidation; X-ray; absorption spectroscopy; RAY-ABSORPTION SPECTROSCOPY; METAL-SUPPORT INTERFACE; PARTICLE-SIZE; PLATINUM; CATALYSTS; CHEMISORPTION; CLUSTERS; EXAFS; COVERAGE; STORAGE; Chemistry, Physical

    Abstract

    Understanding the interaction of hydrogen with subnanometer platinum nanoparticles (NPs) under industrially relevant conditions is of great importance to heterogeneous catalysis. In this work, we investigate the pressure-dependent changes in hydrogen coverage on size- and shape-selected Pt/-Al2O3 NPs by insitu X-ray absorption near-edge structure (XANES) analysis. Difference XANES calculations revealed an increase in the H/Pt ratio from 1.9 to 2.5 upon increasing the hydrogen pressure from 1 to 21bar at room temperature (1bar=100kPa). In addition, extended X-ray absorption fine structure measurements of the local geometrical structure showed changes in PtPt bond length and coordination number, revealing a morphological transformation in the NPs from a 2D to a 3D shape under increasing H-2 pressure at room temperature. Such shape evolution leads to a decrease in the NP-support contact area and is thus expected to affect the NP stability against coarsening.

    Journal Title

    Chemcatchem

    Volume

    6

    Issue/Number

    1

    Publication Date

    1-1-2014

    Document Type

    Article

    Language

    English

    First Page

    348

    Last Page

    352

    WOS Identifier

    WOS:000330636800044

    ISSN

    1867-3880

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