Role and Evolution of Nanoparticle Structure and Chemical State during the Oxidation of NO over Size- and Shape-Controlled Pt/gamma-Al2O3 Catalysts under Operando Conditions

    Authors

    E. Lira; L. R. Merte; F. Behafarid; L. K. Ono; L. Zhang;B. R. Cuenya

    Comments

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    Abbreviated Journal Title

    ACS Catal.

    Keywords

    NO oxidation; Pt nanoparticle; Al2O3; nanoparticle redispersion; PtOx; EXAFS; XANES; TEM; mass spectroscopy; X-RAY-ABSORPTION; METAL-SUPPORT INTERFACE; PT/AL2O3 CATALYSTS; STORAGE/REDUCTION CATALYSTS; HYDROGEN CHEMISORPTION; ELECTRONIC-STRUCTURE; THERMAL-STABILITY; PLATINUM OXIDES; REDUCTION; SPECTROSCOPY; Chemistry, Physical

    Abstract

    The structure and chemical state of size-selected Pt nanoparticles (NPs) supported on gamma-Al2O3 were studied during the oxidation of NO using X-ray absorption near-edge spectroscopy and extended X-ray absorption fine-structure spectroscopy measurements under operando conditions. The data revealed the formation of PtOx species in the course of the reaction that remained present at the maximum temperature studied, 350 degrees C. The PtOx species were found in all samples, but those with the smallest NPs showed the highest degree of oxidation. Moreover, NO-induced nano-particle redispersion was observed at temperatures below 150 degrees C for all catalysts studied. Catalytic tests showed activity toward the oxidation of NO for all samples. Nevertheless, the catalyst with the smallest NPs was found to be the least active, which is explained by a more extensive formation of PtOx species in this catalyst and their detrimental contribution to the oxidation of NO.

    Journal Title

    Acs Catalysis

    Volume

    4

    Issue/Number

    6

    Publication Date

    1-1-2014

    Document Type

    Article

    Language

    English

    First Page

    1875

    Last Page

    1884

    WOS Identifier

    WOS:000337074700028

    ISSN

    2155-5435

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