| Summary: | 碩士 === 國立中正大學 === 化學工程研究所 === 102 === Mesoporous TiO2 nano films were synthesized with a variety of calcination temperature and film thickness for water splitting application. The characterization of the materials were conducted with scanning electron microscope (SEM), X-ray diffraction (XRD), Raman analysis and UV–Vis spectra in order to know the ratio of the anatase and rutile phases of the TiO2.
The experiments of water splitting were carried out with mesoporous TiO2 nano films. The results indicated that the nano film with 60 nm in thickness and synthesized at 500 °С had a higher photocurrent density of 1.149 mA/cm2 . The yield of hydrogen (45.15 μmol) 3 times than that of Sputter TiO2 and Degussa P25 thin film.
The second part of research is the formation of the carbon nano fibers (CNF) by electrospinning, stabilization and carbonnization using polyacrylonitrile (PAN) as the precursor of carbon nanofibers. The diameter of CNF was about 320 nm while the length was about several meters. CNF, carbon nano particle (CNP) and mesocarbon microbead (MCMB) were analyzed by SEM, TEM, Raman and XRD. It was found that the CNF and CNP were turbostratic carbon, while the MCMB was the form of graphite. Three materials were used as anode materials for Li-ion batteries.
The experimental results of the electrochemical studies showed that the CNP obtained the highest initial discharge capacity 385.17 mAh/g while the CNF and CNP had higher irreversible capacity. It was mainly because of the formation of SEI on the amorphous carbon. The MCMB obtained the highest initial coulombic efficiency 94.76 %. After ten cycles, the three materials had coulombic efficiency of more than 95 %, and the CNF had highest charge capacity 285.57 mAh/g, while MCMB was only 249.57 mAh/g. CNF was a higher capacity compared with commercial MCMB.
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