Enhanced hydrothermal stability and oxygen storage capacity of La³⁺ doped CeO₂-纬-Al₂O₃ intergrowth mixed oxides

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• 作者：Liang Wang^a ; Meina Huang^a ; Bin Li^a ; ^{binli@gxu.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Lihui Dong^a ; Guangzhou Jin^b ; ^{jinguangzhou@bipt.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Junbin Gao^b ; Jiahui Ma^b ; Tangkang Liu^a
• 关键词：CeO2-纬-Al2O3 ; La3+ doped ; Intergrowth and coexistence effects ; Hydrothermal stability
• 刊名：Ceramics International
• 出版年：2015
• 出版时间：December 2015
• 年：2015
• 卷：41
• 期：10
• 页码：12988-12995
• 全文大小：1569 K

文摘

La³⁺-doped CeO₂-纬-Al₂O₃ intergrowth mixed oxide powders were synthesized using an improved amorphous citric precursor (IACP) method and then steam-aged with 90% steam and 10% air for 12 h at 788 °C. The synthesized materials were characterized through X-ray diffraction, energy-dispersive X-ray spectrometry, H₂ temperature programmed reduction, Brunauer–Emmett–Teller, and oxygen storage/release capacity (OSC) measurements. La³⁺ was successfully doped into the CeO₂-纬-Al₂O₃ lattice to form an intergrowth system. Strong intergrowth interactions were observed between CeO₂, La₂O₃, and 纬-Al₂O₃ crystallites. The (Ce_0.92La_0.08)_0.4Al_0.6O_2−z(CLA) sample showed a maximum OSC of 979 渭mol g⁻¹; however, the pure ceria sample showed a low OSC of 315 渭mol g⁻¹. The CLA samples maintained a relatively high OSC of 880 渭mol g⁻¹ even after hydrothermal treatment. These results may be attributed to the incorporation of La³⁺ ions into the ceria lattice to form a CeO₂–La₂O₃ solid solution as well as to the intergrowth interactions between the CeO₂–La₂O₃ solid solution and 纬-Al₂O₃. Such interactions affected structural homogeneity and oxygen vacancy formation and inhibit the CLA particles from sintering during steam-aging.