Development of novel nanomaterials for display and catalysis applications
Özet
Nanomaterials established a research presence due to their large variety and unique properties for many areas such as biotechnology, energy, fabrics, construction, food etc. Transparent conductors and catalysis applications are also two other important areas in which nanomaterial studies are carried out. For display applications, metal nanowires, especially silver and copper, draw too much attention as transparent conductors as an alternative to indium tin oxide (ITO), which is the most used material in this market, due to their high conductivity, low cost and availability for flexible device applications which are limitations for ITO. In catalysis applications, using nanomaterials are also important to provide two essential parameters: increasing the efficiency of reactions and lowering the cost. In this thesis, on the whole, we present the synthesis of silver and copper nanowires by optimizing some parameters for controlling the length and diameter of nanowires. For the surface passivation of nanowires, we offered some coating methods with noble metals such as gold, platinum and palladium. Also we investigated the catalytic activity of copper nanowires on dye wastewater treatment. In the first part of this study, effects of polyvinylpyrrolidone (PVP) polymer length and PVP:AgNO3 molar ratio on the efficiency of silver nanowire synthesis and nanowire size were investigated for polyol synthesis method. The results showed that reaction yield is highly depended on these parameters. Also, by using different coating methods such as direct addition or biphasic titration, and by using different noble metal precursors, galvanic exchange reactions on silver nanowire surfaces were studied. The results for coating showed that it is possible to replace silver and noble metal atoms through these methods. The next part of the thesis reports the copper nanowire synthesis ii by two different methods: hydrothermal and solution based synthesis. The copper nanowires showed different size properties for these two methods. In addition, the same coating processes were also performed for copper nanowires and the results are promising as silver nanowires. In the last part, catalytic performance of copper nanowires was studied on degradation reactions of three different organic dyes. Great differences between catalyzed and uncatalyzed reaction periods were observed for all dyes.
