TITLE:
Thermogravimetric Analysis of Zirconia-Doped Ceria for Thermochemical Production of Solar Fuel
AUTHORS:
Friedemann Call, Martin Roeb, Martin Schmücker, Hélène Bru, Daniel Curulla-Ferre, Christian Sattler, Robert Pitz-Paal
KEYWORDS:
Water Splitting; CO2 Splitting; Thermochemical Cycle; Ceria; CO; Solar Fuels; Hydrogen; H2; Zirconia; Synthesis Gas
JOURNAL NAME:
American Journal of Analytical Chemistry,
Vol.4 No.10A,
September
26,
2013
ABSTRACT: Developing an efficient redox material is crucial for
thermochemical cycles that produce solar fuels (e.g. H2 and
CO), enabling a sustainable energy supply. In this study, zirconia-doped cerium
oxide (Ce1-xZrxO2) was tested in
CO2-splitting cycles for the production of CO. The
impact of the Zr-content on the splitting performance was investigated within the
range 0 ≤ x mogravimetric experiments. The results indicate that there is an
optimal zirconium content, x = 0.15,
improving the specific CO2-splitting performance by 50% compared to
pure ceria. Significantly enhanced performance is observed for 0.15 ≤ x ≤ 0.225. Outside this range, the
performance decreases to values of pure ceria. These results agree with theoretical
studies attributing the improvements to lattice modification. Introducing Zr4+ into the fluorite structure of ceria compensates for the expansion of the
crystal lattice caused by the reduction of Ce4+ to Ce3+.
Regarding the reaction conditions, the most efficient composition Ce0.85Zr0.15O2 enhances the required conditions by a temperature of 60 K or one order of
magnitude of the partial pressure of oxygen p(O2)
compared to pure ceria. The optimal composition was tested in long-term
experiments of one hundred cycles, which revealed declining splitting kinetics.