Ceria−Zirconia Solid Solutions (Ce_(1−x)Zr_xO_(2−δ), x ≤ 0.2) for Solar Thermochemical Water Splitting: A Thermodynamic Study
- Creators
- Hao, Yong
- Yang, Chih-Kai
-
Haile, Sossina M.
Abstract
The redox behavior of ceria–zirconia solid solutions (or Zr-substituted ceria, ZSC) with a Zr content of up to 20 mol % is studied by thermogravimetry (TG) between 600 °C and 1490 °C under controlled atmospheres. Thermodynamic properties, specifically standard oxidation enthalpy, ΔH_(oxd)^⊖, and entropy, ΔS_(oxd)^⊖, are derived from TG data. The raw TG results show that the extent of reduction is significantly increased (compared with undoped ceria), even at a low Zr substitution level of 5 mol %. Concomitantly, the magnitude of the thermodynamic functions dramatically decreases as a function of Zr content, particularly at low values of oxygen non-stoichiometry, δ (<3 mol %). Thermochemical fuel production from Zr-substituted ceria generally increases with increasing Zr content under both two-temperature and isothermal cycling conditions. In the case of two-temperature cycling, the benefit is accompanied by a penalty in the (computed) steam-to-hydrogen conversion ratio, whereas it is accompanied by a gain in this ratio for isothermal cycling. Overall, introduction of Zr has the potential to enhance solar-driven thermochemical fuel production, depending on the details of cycling conditions and reactor design.
Additional Information
© 2014 American Chemical Society. Received: August 26, 2014. Revised: September 22, 2014. Published: September 29, 2014. This work was supported in part by the U.S. National Science Foundation (under Grant No. CBET-1038307) and in part by the U.S. Department of Energy, Advanced Research Projects Agency (under Grant No. DE-AR0000182). Additional support was provided by the Recruitment Program of Global Experts of China. We are grateful to Prof. Linda F. Nazar for valuable discussions and to Robert Usiskin, Balaji Gopal Chirranjeevi, Sharjeel Aziz, and Grigorios Panagakos for providing experimental assistance.Additional details
- Eprint ID
- 52477
- Resolver ID
- CaltechAUTHORS:20141208-135234648
- NSF
- CBET-1038307
- Department of Energy (DOE)
- DE-AR0000182
- Global Experts of China Recruitment Program
- Created
-
2014-12-09Created from EPrint's datestamp field
- Updated
-
2021-11-10Created from EPrint's last_modified field