Non-Toxic Renewable Energy Storage via Solar Thermal Decoupled Electrolysis of Iron Oxide

Widespread adoption of renewable solar energy is currently limited by a lack of long term storage commodities. As a preferred option, fuels satisfy flexible requirements including transportability, high energy density, and in the case of hydrogen, clean combustion. Here we will outline a method of producing hydrogen using an iron oxide-based system, which was selected due to its non-toxicity and relative abundance. First, the iron oxide hematite would be decomposed in a solar furnace, producing oxygen and magnetite. Next, the magnetite is reacted through electrolysis to produce hydrogen gas and regenerate the hematite precursor. Two electrochemical methods of testing this reaction were performed with variable temperature and pH; one with magnetite deposited on steel surfaces, and another with magnetite dissolved in etidronic acid. Finally, the pH of the etidronic acid solution was raised to precipitate the phase pure hematite completing the cycle