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Title: Factors Influencing the Stability of Au-Incorporated Metal-Oxide Supported Thin Films for Optical Gas Sensing

There is interest in using Au-nanoparticle incorporated oxide films as functional sensor layers for high-temperature applications in optical-based sensors for measurements in both highly-oxidizing and highly-reducing atmospheres at temperatures approaching 900°C-1000°C because of a relatively high melting temperature combined with the inert nature of Au nanoparticles. This study includes a systematic series of experiments and theoretical calculations targeted at further understanding stability of Au-nanoparticle incorporated TiO 2 films as archetype sensing materials. A combination of thermodynamic modeling and long-term exposure tests were utilized to unambiguously determine that gas stream composition-dependent reactive evaporation of Au (to form predominately Au(g) or AuH(g), depending upon the environment) at the surface of the nanoparticles is the dominant mechanism for mass loss of Au. Primary factors dictating the rate of reactive evaporation, and hence the associated film stability, were determined to be the gas stream temperature and the concentration of H 2, with the former playing a more significant role over the ranges of temperatures (700°C - 800°C) and H 2 concentrations (1% to 29% H 2 by volume) explored. The mitigation of Au-mass loss through reactive evaporation was also successfully demonstrated by depositing a SiO 2 overlayer on the Au-nanoparticle embedded films to preventmore » direct Au-nanoparticle/vapor-phase contact.« less
Authors:
 [1] ;  [2] ;  [2] ;  [1]
  1. National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States)
  2. National Energy Technology Lab. (NETL), Albany, OR (United States)
Publication Date:
Report Number(s):
NETL-PUB-20904
Journal ID: ISSN 0013-4651
Type:
Accepted Manuscript
Journal Name:
Journal of the Electrochemical Society
Additional Journal Information:
Journal Volume: 164; Journal Issue: 4; Conference: Meeting of the Society, Honolulu, HI (United States), 2-7 Oct 2016; Journal ID: ISSN 0013-4651
Publisher:
The Electrochemical Society
Research Org:
National Energy Technology Laboratory, Pittsburgh, PA (United States). In-house Research; Albany Research Center (ARC), Albany, OR (United States)
Sponsoring Org:
USDOE Office of Fossil Energy (FE)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Thin Films; Optical Gas Sensing; Au Nanoparticle; Hydrogen; Fuel Gas; X-ray Photoelectron Spectroscopy
OSTI Identifier:
1374181