Improving Hydrogen Sensing by Adding Additives in Nanostructure WO3 Films

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Fardindoost, Somayyeh | 2009

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Type of Document: M.Sc. Thesis
Language: Farsi
Document No: 39091 (04)
University: Sharif University of Technology
Department: Physics
Advisor(s): Iraji Zad, Azam; Mahdavi, Mohammad
Abstract:
The present work emphasizes on hydrogen resistance- sensing properties of WO3 films prepared by Sol-gel routs. The sol-gel is a simple and low cost rout which makes film with high homogeneity and low processing temperature .To improve Hydrogen sensing we modified WO3 films with Pd catalysts by Sol-gel and Electroless methods. AFM , EDX, SEM , XPS , XRD , were applied to analyze structure, morphology and Chemical composition of the fabricated thin films. We measured resistance sensing behavior of prepared films in exposure to different concentration of Hydrogen. All the films were tested under the same conditions. We measured resistance sensing in exposure to concentration below 10000 ppm Hydrogen in operating temperature ranges of 30 to 350 0C. Our results showed Pd role in improvement of response magnitude from 2 in pure film at 350 0C to 1500 in Pd modified films at room temperature, in exposure to 1000 ppm Hydrogen. The quick response and high sensitivity in exposure to low concentration of Hydrogen makes these sensors reliable in compare to commercial ones
Keywords:
Tungsten Oxide ; Nanoparticles ; Hydrogen Gas Sensor ; Palladium ; Sol-Gel Method ; Electroless

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