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Diplomsko delo sestoji iz trenutnih znanstvenih spoznanj o grafenu, njegovi sintezi, vrstični elektronski mikroskopiji in reakciji redukcije kisika ter eksperimentalnega dela, ki sem ga izvedla z grafenom na osnovi teh metod. Kemijsko naparevanje iz parne faze je eden izmed možnih načinov proizvodnje grafena, ki je cenovno ugoden, primeren pa je tudi za njegovo masovno proizvodnjo. Obsega uvajanje plina, ki služi kot vir ogljikovih atomov, na substrat, ki je navadno ena izmed prehodnih kovin. Na substratu se plin razgradi, ob ohlajanju pa začne na njem rasti grafen. V moji diplomski nalogi sem kot substrat uporabila polikristaliničen platinast disk, kot vir ogljikovih atomov pa je služil metan. Za čim bolj jasno sliko, koliko grafena je zraslo na disku, z vrstičnim elektronskim mikroskopom posnamemo slike platine pred in po rasti grafena. Glavni cilj diplomske naloge je bilo preverjanje katalitske aktivnosti grafena za reakcijo redukcije kisika, saj je ta pomembna v gorivnih celicah s protonsko prevodno membrano in v kovinsko-zračnih baterijah, ki bodo služile za zagotavljanje trajnostnega vira energije s čim manjšim ogljičnim odtisom, saj se zaradi emisij ogljikovega dioksida pri uporabi fosilnih goriv segreva globalno ozračje, kar pa želimo preprečiti, da bo naš planet še vedno naseljiv za prihodnje generacije. The thesis consists of current scientific knowledge of graphene, its synthesis, scanning electron microscopy and oxygen reduction reactions. In the end I conducted experimental research, which I carried out with graphene based on these methods. Chemical vapor deposition is one of the possible methods of graphene production, which is not too expensive and is also suitable for mass production. It involves introducing gas, which serves as a source of carbon atoms, on a substrate, which is usually one of the transition metals. On the substrate, the gas degrades and, when cooled, graphene grows on it. In my thesis, I used a polycrystalline platinum disc as a substrate and methane served as the source of carbon atoms. To see how much graphene has grown on the disk, we took some photos of platinum before and after the growth of graphene with a scanning electron microscope. The main objective of this thesis was to check the catalytic activity of graphene for oxygen reduction reaction, as it is important in fuel cells with a proton exchange membrane and in metal-air batteries, which will serve to provide a sustainable energy source with the least carbon footprint, as carbon dioxide emissions from fossil fuels heat the global atmosphere, which we want to prevent, so that our planet will still be habitable for generations to come |
