Ceria鈥揨irconia Solid Solutions (Ce1鈥?i>xZrxO2鈭捨?/sub>, x 鈮?0.2) for Solar Thermochemical Water Splitting: A Thermodynamic Study

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• 作者：Yong Hao ; Chih-Kai Yang ; Sossina M. Haile
• 刊名：Chemistry of Materials
• 出版年：2014
• 出版时间：October 28, 2014
• 年：2014
• 卷：26
• 期：20
• 页码：6073-6082
• 全文大小：640K
• ISSN：1520-5002

文摘

The redox behavior of ceria鈥搝irconia solid solutions (or Zr-substituted ceria, ZSC) with a Zr content of up to 20 mol鈥? is studied by thermogravimetry (TG) between 600 掳C and 1490 掳C under controlled atmospheres. Thermodynamic properties, specifically standard oxidation enthalpy, 螖H_oxd^{鈯?/sup>, and entropy, 螖S_oxd鈯?/sup>, 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鈥?. Concomitantly, the magnitude of the thermodynamic functions dramatically decreases as a function of Zr content, particularly at low values of oxygen non-stoichiometry, 未 (<3 mol鈥?). 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.}