Hydrogen is a promising, environmentally-friendly fuel source for replacing fossil fuels in transportation and stationary power applications. Currently, most hydrogen is produced from non-renewable sources including natural gas, oil, and coal. Photoelectrochemical (PEC) water splitting is a new renewable energy technology that aims to generate hydrogen from water using solar energy. When light is absorbed by the photocatalyst, an electron-hole pair is generated that interacts with water molecules in a surface reduction-oxidation reaction to decompose the water into hydrogen and oxygen. The current challenge in PEC water splitting is finding low-cost, stable materials with good visible light absorption and high efficiency for water splitting. Recent progress in developing ultra-thin black TiOx via atomic layer deposition(ALD) shows potential for solving these challenges. In comparison to naturally occurring white TiO2, black TiOx has a narrowed band gap, which allows for increased solar absorption (into visible), vastly improving potential for passive operation of PEC water splitting under sunlight illumination. It also exhibits high resistance to photocorrosion. Furthermore, the ability to deposit this material with ultra-precise ALD allows for geometric manipulation to increase charge separation efficiency and absorption. This project aims to improve the performance of PEC devices for water splitting by developing new high surface area photoelectrodes enclosed in a thin layer of black TiOx.
Project end date: 08/03/18