Optical absorption and XPS studies of (Ba_{1∿span style='font-style: italic'>x}Sr_x)(Ce_0.75Zr_0.10Y_0.15)O_{3∿span style='font-style: italic'>δ} electrolytes for protonic ceramic fuel cells

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• 作者：Shivendra Kumar Jaiswal^a ; ¹ ; ^{skj@nitp.ac.in" class="auth_mail" title="E-mail the corresponding author} ; ^{shivendrabhu@gmail.com" class="auth_mail" title="E-mail the corresponding author} ; Jongsup Hong^a ; Kyung Joong Yoon^a ; ^b ; Ji-Won Son^a ; ^b ; Hae-Weon Lee^a ; Jong-Ho Lee^a ; ^b ; ^{jongho@kist.re.kr" class="auth_mail" title="E-mail the corresponding author}
• 关键词：C. Optical properties ; Fuel cell electrolytes ; Oxides ; Photoelectron spectroscopy ; Visible and ultraviolet spectrometers
• 刊名：Ceramics International
• 出版年：2016
• 出版时间：June 2016
• 年：2016
• 卷：42
• 期：8
• 页码：10366-10372
• 全文大小：1116 K

文摘

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 (Ba_1−xSr_x)(Ce_0.75Zr_0.10Y_0.15)O_3−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 (V_f) is maximum for x=0.2 (V_f=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 (Ba_1−xSr_x)(Ce_0.75Zr_0.10Y_0.15)O_3−δ a promising candidate for futuristic and reliable fuel cell technology.