Title

Stability of Platinum Nanoparticles Supported on SiO2/Si(111): A High-Pressure X-ray Photoelectron Spectroscopy Study

Authors

Authors

S. Porsgaard; L. R. Merte; L. K. Ono; F. Behafarid; J. Matos; S. Helveg; M. Salmeron; B. R. Cuenya;F. Besenbacher

Comments

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

Abbreviated Journal Title

ACS Nano

Keywords

platinum nanoparticle; inverse micelle; volatile PtOx; high-pressure; X-ray photoelectron spectroscopy; HP-XPS; atomic force microscopy; AFM; CATALYST DEACTIVATION; DISPERSION CHANGES; THERMAL-STABILITY; MODEL; CATALYST; THIN-FILMS; OXYGEN; SIZE; OXIDATION; OXIDES; PARTICLES; Chemistry, Multidisciplinary; Chemistry, Physical; Nanoscience &; Nanotechnology; Materials Science, Multidisciplinary

Abstract

The stability of Pt nanoparticles (NPs) supported on ultrathin SiO2 films on Si(111) was investigated in situ under H-2 and O-2 (0.5 Torr) by high-pressure X-ray photoelectron spectroscopy (HP-XPS) and ex situ by atomic force microscopy (AFM). No indication of sintering was observed up to 600 degrees C in both reducing and oxidizing environments for size-selected Pt NPs synthesized by inverse micelle encapsulation. However, HP-XPS revealed a competing effect of volatile PtOx desorption from the Pt NPs (similar to 2 and similar to 4 nm NP sizes) at temperatures above 450 degrees C in the presence of 0.5 Tort of O-2. Under oxidizing conditions, the entire NPs were oxidized, although with no indication of a PtO2 phase, with XPS binding energies better matching PtO. The stability of catalytic NPs in hydrogenation and oxidation reactions is of great importance due to the strong structure sensitivity observed in a number of catalytic processes of industrial relevance. An optimum must be found between the maximization of the surface active sites and metal loading (i.e., minimization of the NP size), combined with the maximization of their stability, which, as it will be shown here, is strongly dependent on the reaction environment.

Journal Title

Acs Nano

Volume

6

Issue/Number

12

Publication Date

1-1-2012

Document Type

Article

DOI Link

http://dx.doi.org/10.1021/nn3040167

Language

English

First Page

10743

Last Page

10749

WOS Identifier

WOS:000312563600035

ISSN

1936-0851

Recommended Citation

"Stability of Platinum Nanoparticles Supported on SiO2/Si(111): A High-Pressure X-ray Photoelectron Spectroscopy Study" (2012). Faculty Bibliography 2010s. 3153.
https://stars.library.ucf.edu/facultybib2010/3153