AVS 52nd International Symposium
    Surface Science Monday Sessions
       Session SS1-MoA

Paper SS1-MoA10
Detection of Nitric Oxide using Gold Nanoparticle Catalysts on WO@sub3@ Chemiresistive Sensors

Monday, October 31, 2005, 5:00 pm, Room 202

Session: Catalysis for the Hydrogen Economy
Presenter: B.G. Frederick, University of Maine
Authors: A.L. Martin, University of Maine
J. Wang, Bangor High School
G. Bernhardt, University of Maine
M. Sander, Inst. Materials Res. Eng., Singapore
R.J. Lad, University of Maine
F.G. Amar, University of Maine
B.G. Frederick, University of Maine
Correspondent: Click to Email
Detection of nitric oxide at parts-per-billion levels is important for environmental and medical applications. We have shown that NO can be detected on tungsten trioxide chemiresistive sensors if gold or silver nanoparticles are present. The sensitivity, dynamic range, and response time depend upon the metal coverage and particle size distribution. In the limit that NO to NO@sub2@ conversion and spillover/diffusion is fast compared to NO@sub2@ reaction, the mean field solution is consistent with the initial, linear dependence of sensor response on NO partial pressure. Changes in the gold nanoparticle particle size distribution were measured with high resolution SEM. We have modeled the adsorption and conversion of NO to NO@sub2@ on the metal catalyst, followed by spillover, diffusion and reaction of NO@sub2@ with oxygen vacancies on the WO@sub3@(001) surface using kinetic Monte Carlo simulations. The spatial inhomogeneity results in a non-linear sensitivity curve, which is consistent with sensor response after aggregation.