SYNTHESIS AND CHARACTERIZATION OF LOADED/UNLOADED MESOPOROUS WO3 BASED SEMICONDUCTOR NANOCOMPOSITE BY NANOCASTING ON “HARD TEMPLATE” AND “SOFT TEMPLATE” SUPPORTS. Masters thesis, King Fahd University of Petroleum and Minerals.
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Arabic Abstract
تهدف هذه الدراسة العلمية الى تحضير وتوصيف اكاسيد المعادن شبه الموصله ذات البنية النانوية بهدف تحسين حفزها الضوئي لتستخدم في اختزال ثاني اكسيد الكربون الى هيدروكربونات مثل الميثان، الميثانول وحمض الفورميك. اكاسيد المعادن شبه الموصله ذات البنية النانوية التي تم تحضيرها، توصيفها ودراسة حفزها الضوئي في هذه الدراسة هى أكسيد الإنديوم الثلاثي، اكسيد التنجستن، مركب أكسيد الإنديوم الثلاثي واكسيد التنجستن، اكسيد التنجستن المطعم بعنصر التنتالوم وعنصر النيوبيوم. حضرت اكاسيد المعادن شبه الموصله ذات البنية النانوية با ستخدام طرق كيميائية وبعد ذلك تم استخدام تقنيات التوصيف المناسبة لتوصيف المواد المحضرة لدراسة تركيبها البلوري، مساميتها وخواصها الضوئية. الحفز الضوئي للمواد المحضرة تم دراستة عن طريق استخدامها لاختزال ثاني اكسيد الكربون الى ميثانول بوجود اشعة الليزر. اثبتت هذه الدراسة زيادة كفاءة المواد المحضرة لاختزال ثاني اكسيد الكربون الى ميثانول ويعزي هذا التحسن في كفاءة الاختزال الى طريقة التحضير، التركيب الكيميائي و العناصر الكيميائية المستخدمة في التطعيم.
English Abstract
This thesis focused on synthesis of nanostructured metal oxide semiconductor catalysts, with enhanced photocatalytic activities for application in reduction of CO2 to low carbon fuels, such as methane, methanol, and formic acid. Ordered mesoporous In2O3 semiconductor nanocatalyst was synthesized with increased specific surface area, by nanocasting on SBA-15 template. Pure WO3 nanomaterials as well as In2O3/WO3 nanocomposites were also synthesized, with varied concentrations of the constituent materials, and subjected to various characteristic analyses and photocatalytic applications. Ta-doped and Nb-doped WO3 nanostructures were independently synthesized by hydrothermal process with P-123 support, and changes in the electro-physical and chemical properties of the WO3 nanomaterials were investigated. The nanostructured metal oxide semiconductors synthesized were characterized for various properties such as morphology, crystallinity, composition, porosity, optical properties and UV/visible light characteristics using appropriate characterization techniques including FE-SEM, XRD, UV-VIS absorption, XPS, N2 adsorptiondesorption and photoluminescence. The synthesis technique employed in this work are majorly wet chemical methods like the traditional sol-gel and nanocasting techniques as well as hydrothermal synthetic method. In the traditional sol-gel method, materials were prepared directly from the precursors by precipitation without a template. Contrarily, in nanocasting, the desired nanostructured materials were synthesized on SBA-15 “hard template” to form ordered mesoporous materials with increased specific surface areas. The photocatalytic activities of a number of the synthesized nanomaterials were investigated by applying them as photocatalysts in laser induced photoreduction of CO2 to methanol. Quantum and CO2 conversion efficiencies of the applied catalysts were estimated, and this confirmed the enhancement in their properties due to method of preparation, addition of composite materials or doping.
| Item Type: | Thesis (Masters) |
|---|---|
| Subjects: | Chemistry Physics |
| Department: | College of Engineering and Physics > Physics |
| Committee Advisor: | Gondal, M.A |
| Committee Members: | Yamani, Z.H and Haider, M.B |
| Depositing User: | LUQMAN OLOORE (g201307650) |
| Date Deposited: | 15 May 2016 04:50 |
| Last Modified: | 01 Nov 2019 16:33 |
| URI: | http://eprints.kfupm.edu.sa/id/eprint/139913 |