Uses of Physical Vapor Deposition Processes in Photoelectrochemical Water Splitting Systems

Abstract

AbstractMost of the hydrogen on planet earth is found bound to oxygen atoms in water, making H2O one of the most promising H2 storage molecules. Large availability, non-toxicity and low cost are among the advantages of using H2O as a H2 gas source. However, the decomposition of water into H2 and O2, called water splitting, needs a large amount of energy, increasing the final cost per kg of hydrogen produced. In this context, the energy provided by the sun may be used to power photoelectrochemical cells (PEC) for water splitting to produce cheap and high purity H2. This mini-review will show recent advances on the use of physical vapor deposition (PVD) methods to improve semiconducting electrode performance. PVD enables the preparation of thin layers of expensive materials over photoelectrodes, therefore decreasing PEC systems manufacture costs. Moreover, the interface of between the semiconductor and the evaporated materials can be optimized under high vacuum conditions used in PVD processes and more efficient PEC systems can be obtained.