Nano-Gold Diggers: Au-Assisted SiO2-Decomposition and Desorption in Supported Nanocatalysts

    Authors

    L. K. Ono; F. Behafarid;B. R. Cuenya

    Comments

    Authors: contact us about adding a copy of your work at STARS@ucf.edu

    Abbreviated Journal Title

    ACS Nano

    Keywords

    Au; nanoparticle; SiO2; Si; AFM; atomic force microscopy; XPS; X-ray; photoelectron spectroscopy; NP-support interaction; METAL-CLUSTERS; THERMAL-STABILITY; MODEL CATALYSTS; CO OXIDATION; REACTIVITY CORRELATIONS; ELECTRON-MICROSCOPY; SILICIDE FORMATION; MESOPOROUS SILICA; AU/TIO2 CATALYST; SURFACE SCIENCE; Chemistry, Multidisciplinary; Chemistry, Physical; Nanoscience &; Nanotechnology; Materials Science, Multidisciplinary

    Abstract

    An investigation of the thermal stability of size-selected Au nanoparticles (NPs) synthesized via inverse micelle encapsulation and deposited on SiO2(4 nm)/Si(100) is presented. The size and mobility of individual Au NPs after annealing at elevated temperatures in ultrahigh vacuum (UHV) was monitored via atomic force microscopy (AFM). An enhanced thermal stability against coarsening and lack of NP mobility was observed up to 1343 K. In addition, a drastic decrease in the average NP height was detected with increasing annealing temperature, which was not accompanied by the sublimation of Au atoms/clusters in UHV. The apparent decrease in the Au NP height observed is assigned to their ability to dig vertical channels in the underlying SiO2 support. More specifically, a progressive reduction in the thickness of the SiO2 support underneath and in the immediate vicinity of the NPs was evidenced, leading to NPs partially sinking into the SiO2 substrate. The complete removal of silicon oxide in small patches was observed to take place around the Au NPs after annealing at 1343 K in UHV. These results reveal a Au-assisted oxygen desorption from the support via reverse oxygen spillover to the NPs.

    Journal Title

    Acs Nano

    Volume

    7

    Issue/Number

    11

    Publication Date

    1-1-2013

    Document Type

    Article

    Language

    English

    First Page

    10327

    Last Page

    10334

    WOS Identifier

    WOS:000327752200081

    ISSN

    1936-0851

    Share

    COinS