Nickel Ferrites In the Hercynite Water Splitting Cycle

We have deposited nickel ferrites onto alumina supports using atomic layer deposition (ALD) in order to compare the nickel ferrite hercynite solar thermal water splitting (STWS) cycle to the cobalt ferrite hercynite STWS cycle. STWS occurs by cycling metal oxides through a high temperature reduction step and a lower temperature oxidation step where H₂O oxidizes the oxide and produces hydrogen gas. We have carried out redox cycling in a stagnation flow reactor with in situ mass spectrometery to study oxygen and hydrogen formation rates as well as thermodynamic simulations to understand the entropic/enthapic effects at work. In addition, ALD of ferrites on zirconia supports was carried out to compare the nickel ferrite hercynite cycle with the traditional nickel ferrite cycle.