الفهرس 
Polypyrrole synthesisOnly 14 pages are availabe for public view
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Abstract
Most of the current research focuses on the design of nanocatalysts with promising properities and multifunctional behavior. Conducting polymers possess many interesting properties that enables their applications in different fields. Specifically, PANI and PPY are the focus of many research avenues due to their good characteristics. PANI / PPY-based nanocomposites have a great deal of attention, due to their easy synthesis, high electrical conductivity, high absorption coefficient in the visible light, charge carriers with high mobility, and the good environmental stability. TiO2 as a semiconductor material, has been widely used for environmental applications, due to its low cost and stability for long time against photo- and chemical corrosion. Its band gap energy (Eg) 3.2 eV allows UV light absorption and electrons (e−) and holes (h+) generation, which gives a favorable condition for reduction- oxidation reactions. The highly crystalline structure of TiO2 is important to enhance the photo generated electrons/holes generation and migration. Because of their uniqe properties, nanosized noble metal particles has becoming one of the most active and promising research areas. Among them, silver NPs were extensively used with different substrates due to their surface plasmon resonance in visible light region, significantly optical properties, unique electrical and antibacterial properties. The coating of TiO2 with polymer could attenuate the agglomeration and show firmer absorbance than bare TiO2. Furthermore, TiO2-polymer nanocomposites respond easily toward the visible light as polymer narrows the band gap of TiO2 and the TiO2 aggregations were reduced by polymer modifications. The doping og TiO2-polymer nanocomposites with silver has attracted much attention so as to get high conductivity, excellent catalytic behavior, and surface plasmon resonance in visible light region in additon to the synergistic effect for narrowing of TiO2 band gap and enhancing the photocatalytic activity. Here, we have described procedures for the synthesis and applications of low cost and efficient magnetic nanocatalysts composed of four-components of Ag-PPY/TiO2@Fe3O4 (MTPS) and Ag-PANI/TiO2@Fe3O4 (TPS). The synthesized magnetic nanocomposites act as a highly efficient magnetic nanocatalysts with a synergetic effect between all thier components, PANI & PPY, TiO2, magnetite (Fe3O4) and Ag NPs. Magnetite seeds act as a core to facilitate the separation process of the catalyst from the solution by applying an external magnetic field. This thesis is formed from three chapters as follows: The first chapter deals with an introduction about conducting polymers PANI and PPY, their synthesis, structure, properties and contributions to various human applied fields. In addition, this chapter discussed iron oxide NPs, TiO2, their synthetic methods and their applications. After discussing the noble metals NPs and silver NPs, this chapter navigates through the nanocomposites of PANI and PPY and their catalytic applications especially for the reduction of PNP. The second chapter It was employed to exhibit the practical part for this thesis as chemical’s origin in addition to their purities. Secondly, the preparation methods of the nanocomposites before and after their anchoring with noble metals NPs were discussed. Different methods of characterizations of the synthesized nanocomposites were introduced in addition to the experimental set up for examining the catalytic properties of the prepared heterogenous nanocatalysts for the reduction of PNP. The photocatalytic application of the prepared nanocomposites toward the degradation of MB as a dye model was presented in this chapter as well. The third chapter This chapter focused onto discussing the properties of the prepared nanocomposites and their catalytic and photocatalytic applications. I- The first part deals with synthesis of MTPS nanocomposite as a smart system for catalysis and photocatalysis. Firstly, the part discussed the preparation steps of MTPS nanocomposites starting from Fe3O4, its functionalization, inclusion of TiO2, polymerization of pyrrole and finally the decoration with silver NPs. This part presented the characteristics of all the synthesized materials via the measurement of FTIR spectra, DRS spectra and XRD patterns. Furthermore, the morphology of MTPS nanocomposite was characterized by TEM, SEM, and EDX analyses. The magnetic character of MTPS nanocomposite was visualized using VSM. The catalytic properties of MTPS nanocomposite as a heterogenous nanocatalyst towards the reduction of PNP to the corresponding safe form PAP were investigated. Eventually, the photocatalytic properties of the synthesized nanocomposite as a heterogenous nanocatalyst towards the degradation of MB dye, as a dye model, were examined. Both the catalytic and the photocatalytic properties of MTPS were compared with the reported catalysts. II- The second part deals with the synthesis of Fe3O4@TiO2/PANI nanocomposite decorated with silver nanoparticles (TPS nanocomposite) for enhanced catalytic reduction of PNP and MB photodegradation. The parent magnetic nanocomposite (Fe3O4@TiO2/PANI) was prepared via the in situ polymerization of aniline in the presence of Fe3O4@TiO2. Different techniques were employed for characterizing the formed TPS nanocomposite such as FTIR, XRD, DRS, SEM, EDX, TEM and VSM. The reduction of PNP was taken as a model reaction for testing the efficacy of TPS nanocomposite as a heterogenous nanocatalyst. Moreover, the photocatalytic properties of TPS as a heterogenous nanocatalyst, towards the degradation of MB dye, were examined and compared with the other catalysts reported in the literatures.