Doping Effect of Copper and Copper Oxide on H2S Sensing of Nanostructured WO3

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Nowrouzi, Rasoul | 2011

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Type of Document: M.Sc. Thesis
Language: Farsi
Document No: 43053 (04)
University: Sharif University of Technology
Department: Physics
Advisor(s): Iraji Zad, Azam
Abstract:
The aim of this research is preparation of tungsten trioxide nanoparticles film for hydrogen sulfide gas sensing. These nanoparticles were made by simple and inexpensive sol-gel method. To improve gas sensing properties, various precursors of copper and copper oxides were added to the sol. This solution was coated on alumina substrate by spin coating method. After annealing, sensing properties of samples were studied by measuring the electrical resistance. Best precursor and its molar percentage of copper to tungsten were selected (WO3-Cu2O (1%)). All tests for this sample were done in temperatures below 100 °C and gas concentration lower than 10 ppm. Sensitivity of WO3-Cu2O (1%) to 1 ppm H2S at room temperature and 250 ppb H2S at 100 °C were 8.6 and 1.6, respectively. The selected samples analyze by AFM, XRD, XPS, SEM and EDAX to investigate the surface morphology, composition and grain structure of the layer. The results show that copper oxide as a catalyst decreases operation temperature and increases sensitivity. Finally, effect of annealing in hydrogen gas on sensing properties was investigated
Keywords:
WO3 ; Copper Oxide ; Hydrogen Sulfide Sensor ; Nanostructure ; Nanostructure Films Analysis

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