Title

Formation And Thermal Stability Of Au2O3 On Gold Nanoparticles: Size And Support Effects

Abstract

Gold nanoparticles with two different size distributions (average sizes of ∼1.5 and ∼5 nm) have been synthesized by inverse micelle encapsulation and deposited on reducible (TiO2) and nonreducible (SiO2) supports. The thermal and chemical stability of oxidized gold species formed upon cluster exposure to atomic oxygen have been investigated in ultrahigh vacuum using a combination of temperature-, time- and CO dosing-dependent X-ray photoelectron spectroscopy (XPS), as well as temperature-programmed desorption (TPD). Our work demonstrates that (a) low-temperature (150 K) exposure to atomic oxygen leads to the formation of surface as well as subsurface gold oxide on Au nanoparticles, (b) the presence of the reducible TiO2 substrate leads to a lower gold oxide stability compared to that on SiO2, possibly because of a TiO2 oxygen vacancy-mediated decomposition process, (c) heating to 550 K (Au/SiO2) and 300 K (Au/TiO 2) leads to a near-complete reduction of small (∼1.5 nm) NPs while a partial reduction is observed for larger clusters (∼5 nm), and (d) the desorption temperature of O2 from preoxidized Au clusters deposited on SiO2 depends on the cluster size, with smaller clusters showing stronger O2 binding. © 2008 American Chemical Society.

Publication Date

3-27-2008

Publication Title

Journal of Physical Chemistry C

Volume

112

Issue

12

Number of Pages

4676-4686

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1021/jp711277u

Socpus ID

47049111041 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/47049111041

This document is currently not available here.

Share

COinS