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2. PHD Thesis / Tesis PHD
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Title:	Preparation And Characterization Of Nanogold Doped And Undoped Cobalt Oxide Dispersed Sba 15 Heterogeneous Catalysts For Sustainable Organic Transformations
Authors:	Suraja Pallikkarathodi Viswanathan (P49199)
Supervisor:	Zahira Yaakob, Professor Dr.
Keywords:	Preparation And Characterization Of Nanogold Doped Preparation Of Nanogold Doped Characterization Of Nanogold Doped Preparation And Characterization Of Nanogold Undoped Cobalt Oxide Dispersed Heterogeneous Catalysts For Sustainable Organic Transformations Nanostructured materials
Issue Date:	18-Apr-2013
Description:	Greener alternatives for chemical transformations are essential for the environmental sustainability. The uses of traditional homogeneous catalysts are burdened with several problems like difficulty in separation and recovery of products, disposal of spent catalyst, corrosion, high toxicity and so forth. Heterogeneous eco-friendly catalytic materials are the most important aid for environmentally harmonious processes. Metal oxide based catalysts performing selective redox reactions are of commercial importance. Pollutant removal after commercial processes such as dyeing is also of current relevance. Present study aims the use of nanoparticles of Co3O4 spinel as a catalytically active support for the development of efficient heterogeneous catalysts. The effectual use of the spinel surface is achieved by dispersion over hexagonal mesoporous silica, SBA 15. The main objective of the present study involves the organic transformations over heterogeneous nanogold doped cobalt oxide dispersed SBA 15 systems to reduce the environmental footprint of chemical processes. The combination of supports, i.e., Co3O4 and SBA 15 worked well; and the support systems were excellent adsorbents for dye pollutant removal or functioned as photocatalysts, based on the method of preparation. Sol gel method of preparation with abet of citric acid led to the formation of novel Co3O4 nanoflakes, and were used for methylorange removal from aqueous solutions. The different methods of material synthesis were engaged for SBA 15 preparation for improved performance. The conventional technique of impregnation is successfully chosen for cobalt dispersion over SBA 15. Alcoholic impregnation of Co3O4 over hydrothermally prepared SBA 15 led to formation of efficient photocatalyst for the removal of representative azo dye pollutant methylene blue, whereas aqueous impregnation over a modified SBA 15 led to the development of a competent adsorbent for fast removal of pollutants which gains industrial attention. Heterogenization of nanogold over Co3O4 impregnated SBA 15 was accomplished by deposition precipitation method. The different characterization techniques such as XRD, FTIR, SEM, TEM and BET- SA analysis were engaged for material characterization. Aiming the commercial applications of very active nanogold-based catalysts, some industrially important reactions such as nitrobenzene reduction, benzyl alcohol oxidation and para nitrophenol reduction have been carried out. The nanogold incorporated systems performed well and high selectivity for the desired products under the best conditions is the significance of the present study. 99% of nitrobenzene is reduced to aniline with 100% selectivity. 88% benzyl alcohol is oxidised to benzaldehyde with a selectivity of 100%. The complete conversion of para nitro phenol to para amino phenol was attained immediately after mixing of aqueous solution of reactants with the catalyst.,PhD
Pages:	246
Call Number:	TA418.9.N35 .V537 2013 3
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Engineering and Built Environment / Fakulti Kejuruteraan dan Alam Bina

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