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.