Photocatalytic activity of macroporous ti o2 p25 films
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Transcript of Photocatalytic activity of macroporous ti o2 p25 films
Macro-porous TiO2-P25 composite thick film for
photocatalytic applications
Dr. Hazem Falah Sakeek
Department of Physics
Al-Azhar University - Gaza
المؤتمر الدولي الثاني
للعلوم األساسية والتطبيقية
The Second International Conference on
Basic and Applied Sciences
Oct 9 – 11, 2012
Institute for Materials & Surface
Technology (IMST)
Kiel – Germany
Sponsored by DAAD
The objectives of this research work are:
(1) to use sol-gel technique to produce a macro-porous
TiO2-P25 composite films.
(2) to evaluate the photocatalytic activity of the fabricated
TiO2-P25 composite films.
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Introduction
Environmental contamination, which is growing around the
world or in our daily life, is a serious social problem not to be
neglected.
Examples of such contamination can be endlessly listed as
follows:
— Water pollution caused by industrial and household wastes
— Respiratory diseases caused by air pollutants such as SOx or
NOx
— Room air contamination caused by organic compounds
emerging from newly developed building materials
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Solution for the Environmental contamination
The fact that using energy to eliminate such environmental
contamination increases emission of CO2 resulting in more global
warming, however, leads us to a dilemma not to use energy to
achieve our anti-pollution goal.
We need a new method that can gently harmonize the contaminated
environment to restore original conditions by using natural energy.
One solution to that problem is, Photo-catalyst.
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What is a photo-catalysts?
Catalyst is a substance that makes a chemical reaction more likely to happen by
reducing the activation energy needed to start it.
A catalyst speed up a chemical reaction or make it happen at a lower temperature.
Once the reaction has finished, the catalyst isn't used up.
Photocatalysis means light is involved in making a catalyst do its job. In other
words, light provides the energy that allows the catalyst to work.
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The function of the photo-catalyst are:
Purifying water
Preventing contamination (Sterilization)
Purifying the air
(dissolving NOx)
Deodorizing
Anti-bacteria
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Thin-film Photocatalyst
In order to use TiO2 as an effective photocatalyst for the
above mentioned applications, powder is not an appropriate
form, because it may be blown off by wind or washed out by
water, and when used to purify water, it has to be separated
from the water. Thus, a method to fix the powder is required.
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Film Preperation
Material Used
Titanium (IV) Isopropoxide,
Diethanolamine (DEA) as a
stabilizing agent,
Nanocrystalline TiO2 Titanium
Powder P25, used as filler
Acetyl acetone,
Ethanol,
Polyethylene glycol (PEG 400)
used as a surfactant.
Method
Films prepared by spin-coating at
3000rpm for 20s on a glass
substrate. And annealed at 400oC
for 10min.
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Characterization
XRD
SEM
Optical Properties Measurements for
the films
UV-Visible Absorption of MO for
Photocatalyst activity.
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XRD Spectra for TiO2, P25 Thin films
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XRD patterns of TiO2-P25 composite films calcinated at 400oC
10%w PEG
Without using PEG
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Numerous random macropores are formed through the nanoscale TiO2 particles
Photocatalysis Measurements
Visual degradation of the MO dye
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UV-VIS Absorption Spectra of MO
Absorption spectra of MO dye sol illuminated by UV radiation in
contact with TiO2-P25 films as a function of time
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tkA
ALn
o
Variation of Ln(A/Ao) of MO dye solution in contact with TiO2-P25 composite
film as a function of illumination period at wavelength of 463nm.
Photocatalytic activity for TiO2-P25 Film
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Conclusion
Macroporous TiO2-P25 composite films have been successfully Fabricated
on glass substrate by spin-coating techniques free of cracks and
agglomeration.
The photocatalytic behavior of the films have been investigated.
Future Work
Optimize the P25 loading and study its effect on the photocatalyst.
Study the effect of the film structure (porous size) on the photocatalyst.
Modifying the Film with Noble metals such as Ag, Au, Pt. to extend the
Photocatalyst in the visible region of the spectrum.
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