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Studying and Synthesize of H2S Gas Sensors Based on Modified WO3 Nanostructure Thin Films
, M.Sc. Thesis Sharif University of Technology ; Iraji zad, Aazam (Supervisor) ; Rahimi, Fereshte (Co-Advisor)
Abstract
H2S is a toxic gas used in chemical laboratories and industries. H2S is also liberated in nature due to biological processes and also from mines and petroleum fields. At some threshold level, exposure to concentrations over 10 ppm can result in headaches, irritability, dizziness and in some case leads to death. So that introducing sensors which sense H2S at ppm level with the low response time is so essential. The present work emphasizes on H2S resistance-sensing properties of pure and Pd doped WO3 films prepared by Arc discharge method. XRD, SEM, EDAX and XPS were applied to analyze crystal structure, morphology and chemical composition of the films. The analyzes results showed that films...
An Investigation on Physical and Photochemical Properties of Sol-Gel Derived MWCNT-WO3 Nanocomposite thin Films
, M.Sc. Thesis Sharif University of Technology ; Moshfegh, Alireza (Supervisor)
Abstract
WO3 have good electrochromic, gas sensor, photocatalyst, phoelectrochemical (PEC) properties. due its properties, tungsten oxide have many application in technology and industry. In this thesis, pure WO3 thin film and MWCNT-WO3 nanocomposite thin films with different weight percent of MWCNT/WO3 utilize for energy domain, particular hydrogen production with phoelectrochemical reactions spiliting water. For this purpose, initially WO3 thin films were deposited on glass and ITO substrates using sol-gel dip-coating method. Optical and surface properties of the films dried at 100ºC and annealed at 400 ºC had been investigated. UV-Visible spectrophotometer, atomic force microscopy (AFM), X-ray...
Doping Effect of Copper and Copper Oxide on H2S Sensing of Nanostructured WO3
, M.Sc. Thesis Sharif University of Technology ; Iraji Zad, Azam (Supervisor)
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...