Magnesioferrites for solar thermochemical fuel production

Solid solutions of iron oxide in MgO, prepared using the solid state reaction method (SSR), were investigated for solar thermochemical water splitting/carbon dioxide splitting (STC-WS/CDS). Experimental results show that 20 mole% magnetite (Fe3O4) in MgO has a hydrogen (H2) production capacity of 6.12 ± 0.22 cm3 g−1total material when thermally reduced at 1450 °C (Tred) under an inert environment and oxidized at 1200 °C (Tox) with excess steam. This compares favorably with cerium dioxide (CeO2), which has proven to be an excellent STC-WS/CDS material, with H2 production 2.91 ± 0.15 cm3 g−1total material at Tred = 1450 °C and Tox = 1200 °C, and 4.34 ± 0.2 cm3 g−1total material at Tred = 1500 °C and Tox = 1200 °C. 20 mole% Fe3O4 in MgO has advantages of lower operating temperature and higher production capacity. The partial pressure of oxygen (PO2) during thermal reduction is on the order of 10−4 atm, which can be achieved using existing industrial vacuum pump technology. These advantages make this material a viable option for further study in solar thermochemical fuel production applications.