Solar thermal water splitting is a promising method to produce clean hydrogen from water. The principle relies on redox cycles involving a two-step reaction: (i) Removal of oxygen anions from the lattice of reducible material; (ii) oxidation due to re-incorporation of oxygen anions into the lattice upon water splitting. Among the most promising oxides are those based on CeO2 because of its stability [1], however its high reduction temperatures (&gt;1500 oC) makes its use unpractical. To overcome such problem, many researchers have pursued doping of this oxide by other metal cations [2, 3]. In this work we present a study of a series of solid solutions of the form of CexFe1-xO2 (x&lt;1); where part of Ce4+ cations are substituted by Fe3+ cations (aliovalent dopant). The incorporation of Fe into CeO2, creating neutral oxygen vacancies, results in lattice deformation which in turn decreases the energy needed for the reduction of Ce4+ (upon the removal of oxygen atoms from the lattice). Moreover, we investigate the extent of reduction of both Ce4+ and Fe3+ cations by the change in their electronic core and valence levels in an attempt to correlate these reductions to the mass loss (TGA) and thermal reaction (hydrogen production from water). 1. W. C. Chueh, C. Falter, M. Abbott, D. Scipio, P. Furler, S. M. Haile, A. Steinfeld. High-Flux Solar-Driven Thermochemical Dissociation of CO2 and H2O Using Nonstoichiometric Ceria Science, 330 (2010) 1797-1801. 2. I. I. Al-Shankiti, F. Al-Otaibi, Y. Al-Salik, H. Idriss, Solar Thermal Hydrogen Production from Water over Modified CeO2 Materials. Top Catal. 56 (2013) 1129–1138. 3. Y. Al-Salik, I. Al-Shankiti and H. Idriss, Core level spectroscopy of oxidized and reduced CexU1−xO2 materials. J. Electron Spectrosc. Relat. Phenom., 194 (2014) 66-73.

Electronic and reaction study of doped CeO2 with Fe cations for hydrogen production from water

249th National Meeting (2015)

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