Band gap tailoring of flower-like rutile-phased TiO2 nanostructured film grown via facile hydrothermal doping process for photocatalytic degradation of methylene blue
One of the major drawback of TiO2 is its band gap. Among other approaches, doping process can be considered as one of the best options. However the current method in doping process has multiple and complex preparation steps that prolong the time for sample fabrication. Here, this study aimed t...
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| Format: | Thesis |
| Language: | English English English |
| Published: |
2021
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| Subjects: | |
| Online Access: | http://eprints.uthm.edu.my/4126/2/24p%20NOOR%20KAMALIA%20ABD%20HAMED.pdf http://eprints.uthm.edu.my/4126/1/NOOR%20KAMALIA%20ABD%20HAMED%20COPYRIGHT%20DECLARATION.pdf http://eprints.uthm.edu.my/4126/3/NOOR%20KAMALIA%20ABD%20HAMED%20WATERMARK.pdf |
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| Summary: | One of the major drawback of TiO2 is its band gap. Among other approaches, doping
process can be considered as one of the best options. However the current method in
doping process has multiple and complex preparation steps that prolong the time for
sample fabrication. Here, this study aimed to dope the rutile-phased TiO2 film with
silver (Ag) and nitrogen (N) by using facile hydrothermal method to shorten the
preparation time of doping process to reduce the band gap of TiO2. In this study, the
film was produced by using facile hydrothermal method conducted at 150 °C for 10
hours. The ability of Ag and N element in reducing the band gap is well established.
Thus, these dopants were used in facile hydrothermal method to investigate the ability
of this method in tailoring the band gap. For Ag-doped TiO2, X-ray photoelectron
spectroscopy (XPS) showed that the amount of Ti3+
-oxygen vacancy defects amplified
after doping, whereas transmission electron microscopy (TEM) discovered that (110)
and (111) facets were the exceptionally exposed facets. Conversely, for N-doped TiO2,
XPS discovered that the amount of Ti3+
-oxygen vacancy defects reduced after doping,
while TEM showed that the (101) and (111) facets were exceptionally exposed facets.
The band gap energy was successfully reduced via this method. The band gap energy
for undoped TiO2 film is 3.21 eV and after doping process with Ag and N element, the
band gap value was reduced to 3.12 and 3.16, respectively. The Ag-FR TiO2 film
doped with 1wt% Ag showed maximum degradation of methylene blue with 20%
higher degradation as compared with the undoped TiO2. N-FR TiO2 2.0 wt% showed
only a 6% increase in the photodegradation of methylene blue. The Ag doped TiO2
displayed the best photocatalytic activity compared to N doped TiO2. The effect of the
synergy between the (110) and (111) facets, together with the Ti3+
-oxygen vacancy
from the doped Ag, played a crucial role in decreasing the band gap as well as acting
as electron traps to inhibit electrons and holes recombination, which prolonged the life
of the photogenerated holes and electrons, thus enhancing the photocatalytic activity |
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