Perovskite-type materials containing metal and cerium cations have been used as catalysts, membranes, electrodes in fuel cells, and hydrogen pumps. The effect of strontium doping on the perovskite-type structure has been evaluated and effectively maintains the cubic structure of (Ba1-xSrx)(Ce0.75Zr0.10Y0.15)O3-δ. X-ray photoelectron spectroscopy (XPS) was performed on the oxidation states of barium, strontium, cerium, zirconium, yttrium and oxygen. With strontium doping, the oxidation state of cerium ions in 4+ increases and results in the decrease in oxygen vacancy concentration. These are attributed to the strong binding energy of (A/B)-O bond which in turn, enhances the structural stability of electrolyte system. The free volume (Vf) is maximum for x=0.2 (Vf=33.1 Å3) and then decreases with further strontium insertion. The optical absorption peaks are attributed to charge transfer transitions and energy band gap (increases from ∼4.13 to ∼4.35 eV). However, the increase of band gap is only ∼5% with partial replacement of barium by strontium. These characteristics are useful to make (Ba1-xSrx)(Ce0.75Zr0.10Y0.15)O3-δ a promising candidate for futuristic and reliable fuel cell technology.
Bibliographical noteFunding Information:
This work was supported by the New & Renewable Energy Core Technology Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) granted financial resource from the Ministry of Trade, Industry & Energy , Republic of Korea (No. 20143030031430 ) and partially funded by the Institutional Research Program of KIST (No. 2E26081 ).
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All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Process Chemistry and Technology
- Surfaces, Coatings and Films
- Materials Chemistry