Towards the Understanding of Sintering Phenomena at the Nanoscale: Geometric and Environmental Effects

    Authors

    F. Behafarid;B. R. Cuenya

    Comments

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    Abbreviated Journal Title

    Top. Catal.

    Keywords

    Coarsening; Sintering; Ostwald-ripening; Diffusion-coalescence; Operando; Pt; Au; TiO2; SiO2; ZrO2; Al2O3; Micelle; Nanoparticle; Environment effect; Interparticle distance; Size effect; Thermal; stability; Encapsulation; Redispersion; SUPPORTED METAL-CATALYSTS; TRANSMISSION ELECTRON-MICROSCOPY; SCANNING-TUNNELING-MICROSCOPY; SULFURIC-ACID DECOMPOSITION; PARTICLE-SIZE DISTRIBUTIONS; TEMPERATURE-PROGRAMMED DESORPTION; IN-SITU; THERMAL-STABILITY; MODEL CATALYSTS; CO OXIDATION; Chemistry, Applied; Chemistry, Physical

    Abstract

    One of the technologically most important requirements for the application of supported metal nanoparticles (NPs) to the field of heterogeneous catalysis is the achievement of thermally and chemically stable systems under reaction conditions. For this purpose, a thorough understanding of the different pathways underlying coarsening phenomena is needed. In particular, in depth knowledge must be achieved on the role of the NP synthesis method, geometrical features of the NPs (size and shape), initial NP dispersion on the support (interparticle distance), support pre-treatment (affecting its morphology and chemical state), and reaction environment (gaseous or liquid medium, pressure, temperature). This study provides examples of the stability and sintering behavior of nanoscale systems monitored ex situ, in situ, and under operando conditions via transmission electron microscopy, atomic force microscopy, scanning tunneling microscopy, and X-ray absorption fine-structure spectroscopy. Experimental data corresponding to physical-vapor-deposited and micelle-synthesized metal (Pt, Au) NPs supported on TiO2, SiO2 and Al2O3 will be used to illustrate Ostwald-ripening and diffusion coalescence processes. In addition, the role of the annealing environment (H-2, O-2, water vapor) on the stability of NPs will be discussed.

    Journal Title

    Topics in Catalysis

    Volume

    56

    Issue/Number

    15-17

    Publication Date

    1-1-2013

    Document Type

    Article

    Language

    English

    First Page

    1542

    Last Page

    1559

    WOS Identifier

    WOS:000324825500020

    ISSN

    1022-5528

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