Solar energy concentrating reactors for hydrogen production by photoelectrochemical water splitting

The use of solar energy to produce hydrogen by electrolysis is one potential renewable hydrogen source to fuel a future hydrogen economy. A cost-effective, renewable source of hydrogen is needed to reduce the emissions of carbon dioxide that occur with hydrogen-production methods utilizing fossil fuels. This report describes the design, construction, and testing of simple and inexpensive photoelectrochemical (PEC) reactors capable of producing hydrogen via water electrolysis using solar energy. We measured the light-focusing properties of two types of PEC reactors with curved surfaces and containing a clear aqueous fluid that resulted in the focusing of solar irradiance within the reactor. One reactor was a teardrop shaped plastic-film bag reactor, and the other was an acrylic spherical tank reactor. The spherical tank reactor had the best light-focusing properties, with up to a factor of 3.7 increase in the solar energy (and thus hydrogen production) for PEC cells mounted at the optimal point within the reactor electrolyte.