| Summary: | 碩士 === 國立清華大學 === 動力機械工程學系 === 99 === The most critical process in both low temperature fuel cells and Li/air batteries is the oxygen reduction at the cathode of these electrochemical devices. The rate-limited process of the catalytic mechanism is extremely important to be fully understood in the nanoscale transport phenomena.
This research intends to use computational quantum mechanics to simulate the detailed processes, including oxygen molecule adsorption, water molecule adsorption, and hydroxyl production, on a platinum atom which is doped on the surface of carbon nanotubes (CNT) and graphene nanoribbons (GNS). They are also doped with nitrogen atoms for decreasing the catalyst cost. We use the computational techniques to simulate the catalytic mechanism of the oxygen reduction at the cathode. The 1st step is to dope Pt atoms onto the CNT surface and to dope N atoms onto the graphene nanoribbons, then to observe the phenomenon of the novel electrode adsorbing the oxygen molecule in the atomistic scale. The 3rd step is to break the bond between two oxygen atoms and to generate a hydroxyl radical with one of the hydrogen atoms in the nearby water molecule. It is possible to predict the bonding energy and bond length between atoms and hence the easiness of breaking and recombination of the bonds. The detailed catalytic performance of the novel catalyst at nano scale is predicted in this research.
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