Analysis of a photochemical water splitting reactor with supramolecular catalysts and a proton exchange membrane

In this paper, a new type of photochemical water splitting system is proposed and analyzed. The system comprises two reactors in which photocatalytic half-reactions of water reduction and water oxidation are conducted. The two reactors are divided by a proton conducting membrane. Complex molecular devices based on ruthenium-(bipyridine)32+ photosensitizers are dissolved in both reactors, which generate electrons or holes when exposed to high energy photonic radiation, and act as catalysts for water splitting. The selected molecular devices for water reduction have a unique property to enhance the existence time of photoelectrons, such that the likelihood of generated electron pairs to produce a molecule of hydrogen is increased. In this study, the physical–chemical processes are analyzed and the main design parameters of the reactor are determined. The engineering design consists of a photochemical reactor, a mass flow controller to supply the fresh water, and two fans that extract the products of water splitting.