Photocatalytic Applications of Nanocomposites of HfO2 - TiO2 Nanorod Arrays Using Sputtering

  • 馮 皓哲

Student thesis: Master's Thesis


This research reports a novel application of high-k material (HfO2) to photocatalysis for the first time by enabling the defects in HfO2 to trap charge carriers to achieve synergistic photo-decomposition of organic pollutants (methylene blue) A comprehensive investigation into the fabrication of nanocomposites of HfO2-TiO2 nanorod arrays using reactive sputtering was conducted Well oriented and a maximum separation of approximately 500 nm of HfO2 nanorods were achieved which enhanced charge carrier transport along the 1D nanoarchitecture The optimal coupling between HfO2 and TiO2 for photocatalysis was identified as 4 layered HfO2/TiO2 nanorods with thicknesses of 375nm/100nm for each layer The sample (200 ppm) was found to photodegrade 70 % of a methylene blue solution (5 ppm) in 90 minutes under 30 W UV irradiation The synergistic photocatalytic effect was interpreted using the energy band diagrams of the HfO2-TiO2 system and attributed to the circumstance that the photogenerated electrons in TiO2 were trapped in the gap state of VO2+ in HfO2 nanorods and then pumped into the conduction band of HfO2 The trapping mechanism was further analyzed by performing the measurement of photoluminescence spectroscopy Another interesting application of the system to a photoelectrochemical reaction was demonstrated as well
Date of Award2014 Aug 5
Original languageEnglish
SupervisorKao-Shuo Chang (Supervisor)

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