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Theoretical and Experimental Study of the Influence of Chemical Environments and Investigation of their Effects on the Kinetics of Redox Reactions using Metal and Metal Oxide Nanocatalyst

Kohantorabi, Mona | 2018

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 51353 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Gholami, Mohammad Reza
  7. Abstract:
  8. Bimetallic nanoparticles with unique structure, synergistic effect between two metals, and the tunable physical/chemical properties have been used for catalysis. Various methods exist for the staibility, and improvement of the catalytic performance of nanoparticles. In this thesis, different co-catalysts were applied to increase tha staibility, and activity of nanoparticles and metal oxides. In this way, Ni-based bimetallic nanoparticles including CuNi, CoNi, and AgNi, and AgPt with different concentrations were synthesized on the cerium oxide nanorods derived from cerium metal-organic frameworks and magnetic graphene oxide nanosheets, respectively and characterized. The catalytic performance of catalysts was evaluated in 4-nitrophenol reduction reaction by NaBH4 as reducing agent. The mechanism of reactions was studied, and the adsorption equilibrium constant of 4-nitrophenol, and borohydride was calculated by using Langmuir-Hinshelwood isotherm. The energy of activation, and thermodynamic parameters have also been determined. In the other section, core-shell nanostructures including Fe3O4@FeIII-MOF-5, and CeO2-g-C3N4 were prepared to increase the staibility, and activity of Au nanoparticles. The catalytic activity of these nanocomposites was investigated in cyclohexene, and aromatic alcohols oxidation by molecular oxygen, respectively. The mechanism of reactions was studied in details. The study of the solvent effect in this reaction showed that the polarity, and hydrogen bond acceptor ability are two important parameters for choosing solvent in radical reactions. In another study, multiphasic nanocomposite was synthesized by using ionic liquid. The catalytic activity of PtPd bimetallic nanoparticles on the surface of SiO2@GO supported ionic liquid was evaluated in cyclohexene oxidation. Ionic liquid layer as a co-catalyst leads to staibility of the nanoparticles on the surface of catalyst, and increases the polarity of the catalyst surface which improves the staibility of radical intermediates, and reaction efficiency. In the final part, the role of transient species generated by photo sensitization of natural organic matter on solar and photo-Fenton process was studied in inactivation of E.coli bacteria. The second order rate constant of two active species was calculated. Also, the effect of Fe2+ as homogenous catalyst, and Ag/ZIF-67@GO was investigated in activation of different oxidants. The photocatalytic performance of Ag/ZIF-67@GO was evaluated in degradation of pollutants including phenol, and E.coli bacteria under visible light. The results showed that, these methods can improve the water treatment process in the presence of sunlight
  9. Keywords:
  10. Oxidation-Reduction Reaction ; Kinetics Study ; Solvent Effect ; Water Treatment ; Core-Shell Nanostructure ; Bimetallic Nanoparticles ; Multiphasic Nanocomposite

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