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ELECTROCHEMICAL
DEPOSITION OF TITANIUM DIOXIDE (TIO2) THIN FILMS
This research involves photo-electrochemical hydrogen (H2) production
from water using solar energy. Hydrogen is considered to be a potential
future fuel for several reasons. Hydrogen has one of the highest
energy densities of all fuels(150 MJ/kg vs. 50MJ/kg for fossil fuels).
The production of hydrogen by solar water splitting will reduce
large amounts the emission of the greenhouse gases. Hydrogen as
fuel is virtually unlimited because it reacts with oxygen to produce
water once again.
In order to improve photo-electrochemical hydrogen production we
need discover better photo-catalytic materials. I am working on
the electro-deposition of titanium dioxide (TiO2) thin films. Titanium
dioxide is considered a good candidate because its band gap energy
of 3eV is greater than the energy required for water splitting (1.23eV).
TiO2 is also corrosion resistant. The problem with TiO2 is that
it does not absorb solar energy very well due to its large bandgap.
I have been working on electodepositing TiO2 from a TiCl4 electrolyte
initially varying voltage and time. After deposition the samples
were calcine at high temperatures (450oC) for several hours in order
to crystallize the TiO2 and to remove impurities. The final step
was to test the samples by measurient photocurrent. We looked at
our results to find which deposition conditions yielded the most
photoactive films. With those conditions we can repeat this procedure
several times changing parameters like temperature and pH. The goal
is to obtain high quality TiO2 films. If we are successful, the
next step is to use combinatorial chemistry in order to vary the
composition of transition-metal doped TiO2 in order to modify its
bandgap and improve its solar energy absorbtion
View
final presentation as PDF
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