Semiconductors are useful candidate for photocatalysis, solar energy can be used to carry out chemical reactions including H₂ fuel generation from water.

Semiconductor photocatalysts are semiconductors which are able cause and/or accelerate chemical reactions upon light absorption, typically sunlight. By utilizing the energy of absorbed photons, photocatalysts can be optimized carry out a wide variety of important chemical processes such as

• Environmental remediation - the destruction of organic pollutants for water or air purification
• Solar Fuels Production - production of fuels, H₂ from water or methane/methanol from CO₂

Semiconductors can be used in photocatalysis as particle dispersions or in photoelectrochemical mode. Several hybrid structures have been envisaged to improve photocatalytic performance of semiconductors such as semiconductor-semiconductor, semiconductor-metal, semiconductor-Reduced Graphene Oxide (RGO) nano-assemblies. It is important we understand the intricate interface electron dynamics in all of these assemblies which will allow us to use these systems in various applications. Our research interests include understanding the behaviour of the above nano composited used for photocatalysis.

Photocatalytic Properties of TiO₂

Titanium dioxide (TiO₂) is a semiconductor with a band gap of 3.2 eV. It is an abundant material with wide-ranging uses, and it is known to be exceptionally stable in a variety of conditions. TiO₂ is frequently used as a whitener in both foods and industrial products like sunscreen or paint. Research has also shown that TiO₂ can be used to destroy organic compounds, prevent fogging of glass, and even split water into hydrogen and oxygen.

In our lab, we have done extensive research into understanding both the capabilities and fundamental processes of TiO₂. We have explored its ability to decompose molecules and its use as a substrate for dye-sensitized, quantum dot-sensitized, and solid state solar cells. The photocatalytic activity of TiO₂ comes from two sources: 1) generation of OH^· radicals by oxidation of OH^- anions and 2) generation of O₂^- radicals by reduction of O₂. Both of these radical anions can react with other species to degrade or otherwise change them, making TiO₂ an effective photocatalyst for many applications. The anatase phase of TiO₂ is arguably the most photoactive, and a great portion of the literature focuses on the use of this crystalline phase. Still, the more thermodynamically stable form of TiO₂, rutile, has also been the focus of a great deal of work.

• Photocatalysis - Background information and history of photocatalysis
• Uses and Properties of TiO₂ - Further information on the photocatalytic properties and the industrial and commercial uses of Titanium Dioxide