Preparation and characterization of ZIF-67/ TiO₂) thin film
Titanium dioxide (TiO₂) is one of the most widely used photocatalyst due to its nontoxic, low cost, good chemical stability, elemental abundance, and photocatalytic properties. But there are some problems faced by TiO₂ first is that if TiO₂ used is in the powder form an additional separation proc...
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| Format: | Academic Exercise |
| Language: | English |
| Published: |
2015
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| Subjects: | |
| Online Access: | https://eprints.ums.edu.my/id/eprint/17744/1/Preparation%20and%20characterization.pdf https://eprints.ums.edu.my/id/eprint/17744/ |
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| Institution: | Universiti Malaysia Sabah |
| Language: | English |
| Summary: | Titanium dioxide (TiO₂) is one of the most widely used photocatalyst due to its nontoxic,
low cost, good chemical stability, elemental abundance, and photocatalytic
properties. But there are some problems faced by TiO₂ first is that if TiO₂ used is in
the powder form an additional separation process is needed to separate the TiO₂
particles from the wastewater after the treatment. TiO₂ has a high bandgap which
requires UV-A light to activate it. The high recombination rate of electron hole pair
occurs before the photocatalytic process starts. ZIF-67 is well known for its porosity
properties. It is used in this study to act as an adsorbent to adsorb organic dye on
the surface of TiO₂ to allow photodegradation to occur and at the same time forming
synergetic effect with TiO₂ to reduce its band gap from UV region to visible light
region. ZIF-67/TiO₂ thin film is form by using dip-coating method. The morphology of
ZIF-67/TiO₂ is observed by using SEM. A square-like shape of ZIF-67 is observed on
the surface of TiO₂ thin film. The photodegradation result obtained show that ZIF-
67/TiO₂ (43.63%) has a lower photodegradation efficiency than un-doped TiO₂
(58.81%) under the irradiation of UV-A light. This shows that ZIF-67 does not
enhance the photocatalytic ability of TiO₂ under irradiation of UV-A light. This may
cause by the combination of ZIF-67 with the Co-doped TiO₂ thin film does not show a
synergetic effect in photodegradation. Besides that, ZIF-67 does not overcome the
high recombination rate of electron hole pair of TiO₂ by adsorbing MB longer on the
surface. But from this study shows that cobalt can act as a dopant to enhance the
photocatalytic properties of TiO₂ in the visible light region. Co-doped TiO₂ shows a
photodegradation efficiency of 25.27 % compared to un-doped TiO₂ which is only
14.36%. |
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