Research Description:

Synthesis of Titanium and Vanadium Oxide Based Materials for Photoelectrochemical Production of Hydrogen using the Solar Spectrum

Hydrogen production from sunlight offers a potentially renewable source of energy without harmful byproducts. The lack of suitable materials remains the biggest obstacle to efficient production. Photoelectrochemical (PEC) cells operate with two electrodes, at least one of which is a semiconductor exposed to light. When light with energy greater than that of the band gap of the material is absorbed, an electron is excited from a valence to conduction band resulting in the formation of oxygen and hydrogen gas at separate electrodes.

The solar spectrum contains mostly visible light, thus the optimal material would have a band gap that allowed for efficient absorption of visible light. Theoretically, 1.23 eV is required for electrolysis of water. However, due to energy losses within a PEC cell, 1.6 to 2 eV is typically required. The band gap of titania (titanium dioxide) is relatively high which means that not very much of the solar spectrum is available for conversion. Despite this drawback, titania remains a good candidate due to its corrosion resistance. This study aims at modifying a titania film with vanadium oxide to more effectively absorb sunlight.

The titania/vanadium oxide photo-anode will be synthesized by creating a film of titania and vanadium oxide particles. Titanium oxide and vanadium oxide precursors will undergo vapor phase hydrolysis to form particles. These particles will be characterized according to their crystalline phase and size. Particles will then be adhered to a titanium metal sheet to form the photo-anode. Properties of the photo-anode will be determined before it is incorporated into a photoelectrochemical cell with a platinum cathode to measure the photocurrent, photovoltage, and hydrogen production.