عنوان :
بررسي خواص رنگزايي شيميايي در نانو ساختارهاي اكسيد تنگستن
مقطع تحصيلي :
كارشناسي ارشد
محل تحصيل :
اصفهان: دانشگاه صنعتي اصفهان، دانشكده فيزيك
صفحه شمار :
[ده]،110ص.: مصور،جدول،نمودار
يادداشت :
ص.ع.به فارسي و انگليسي
استاد راهنما :
مهدي رنجبر
استاد مشاور :
پرويز كاملي
توصيفگر ها :
سل-ژل , كاتاليست پالاديوم , دماي بارپخت , احياي هيدروژني
تاريخ نمايه سازي :
11/4/91
استاد داور :
هادي سلامتي، جواد هاشمي فر
چكيده فارسي :
به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي
چكيده انگليسي :
Investigation of Chemochromic Properties of Nanostructured Tungsten Oxide Azam Hemati a hemati@ph iut ac ir 1390 10 04 Department of Physics Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Dr Mehdi Ranjbar ranjbar@cc iut ac irAbstract Tungsten oxide is an n type semiconductor with wide band gap energy This metal oxide hasmany applications such as electrochromic photocatalyst and gas sensors Among the variousproperties chemochromic properties in the presence of hydrogen gas have much attention Hydrogen is a colorless odorless and tasteless gas As a result more attention is needed to be paidto hydrogen as a clean fuel in household and transportations applications It is a highly flammablefuel with a wide combustion range of 4 75 Therefore detection and leakage control of this gasis a challenging subject In the presence of hydrogen gas changes the optical properties of tungstenoxide thin films and the colure of layer convert from a transparent to an absorbing blue state Thisproperty makes a good option the tungsten oxide films as optical hydrogen sensor In this study atfirst the peroxopolytungstic acid P PTA sol was prepared according to the method of Kudo et al Then the transparent orange sol has been spin coated on glass substrates In order to study theeffect of annealing temperature on different properties of samples the as prepared films wereannealed at different temperatures 100 200 300 and 400 C In order to deposit palladiumnanoparticles on tungsten oxide surface drops of a 0 2 g l PdCl2 solution were transferred to thesurface of layers by hydrogen reduction By this method the samples were strongly and uniformlycolored Among the samples of different annealing temperature the sample of 400 C was betterconsiderably in gasochromic switching rate as well as coloring depth Structural chemical surfacemorphology optical and hydrophilic properties of layers is examined Amorphous WO3 structure isobserved in X ray Diffraction XRD patterns of dried gel and un annealed films However heattreatment at 400 C 500 C results in formation of monoclinic WO3 structure respectively By theFourier transform infrared FTIR spectroscopy were determined the chemical bonds of thesamples In order to study the morphology of the films surfaces AFM was used The result of thisanalysis showed that with increasing of annealing temperature increases the degree ofcrystallization In order to study on the hydrophilicity property of layers contact angle of waterdroplet with surface is measured by the contact angle measurement The optical properties of layerswere measured with a spectrophotometer UV Vis at the spectral range 190 1100 nm Keywords Tungsten oxide Sol gel Chemochromic properties Palladium catalyst Annealing temperature Hydrogen reduction
استاد راهنما :
مهدي رنجبر
استاد مشاور :
پرويز كاملي
استاد داور :
هادي سلامتي، جواد هاشمي فر
