Ce0.5Zr0.5O2觸媒粉末因其具有優異之儲氧性質(Oxygen storage capacity, OSC)，在汽車觸媒轉換器中扮演相當重要的角色。但Ce0.5Zr0.5O2在高溫經過長時間的持溫後會產生相分離的現象，形成富Ce相和富Zr相，而使儲氧性質劣化。本研究以化學共沉法製備Ce0.5Zr0.5O2膠體粉末，經過700 ℃的煅燒，持溫2小時，得到Ce0.5Zr0.5O2的奈米觸媒粉末，再以含浸法加入不同添加量鋇離子後，以1000 ℃持溫2小時做熱處理，觀察添加鋇對於Ce0.5Zr0.5O2相分離的影響。由XRD圖譜發現，添加鋇到Ce0.5Zr0.5O2之後，Ce0.5Zr0.5O2的富鋯相變少，而且鋇會和Ce0.5Zr0.5O2中的Zr產生BaZrO3二次相，當BaZrO3產生後，粉末的比表面積上升，同時粒徑大幅變小，顯示BaZrO3能夠阻礙Ce0.5Zr0.5O2的凝聚成長，也抑制Ce0.5Zr0.5O2的相分離，但是添加過多的鋇，反而造成粉末的凝聚，使比表面積下降。OSC的結果顯示，添加微量的鋇有助於改善Ce0.5Zr0.5O2的儲氧能力，且鋇添加量為5wt%時，Ce0.5Zr0.5O2的儲氧能力最大。

Ce0.5Zr0.5O2 powders play an important role in three-way catalysts for its outstanding oxygen storage capacity. However, Ce0.5Zr0.5O2 phase would separate into Ce-rich phase and Zr-rich phase after high temperature calcinations, which result in the degradation of OSC properties. In this study, the Ce0.5Zr0.5O2 gels were synthesized by the co-precipitation method, and calcined at 700℃ for 2 h to obtain the Ce0.5Zr0.5O2 powders. Then, different amounts of Ba2+ ions were introduced into Ce0.5Zr0.5O2 powders using impregnation method and subsequently calcined at 1000℃ for 2 h to obtain BCZ series powders. The effects of Ba2+ ions on the phase development, texture and oxygen storage capacity of Ce0.5Zr0.5O2 were investigated. The XRD pattern indicated that Ba2+ ions would react with ZrO2 to form BaZrO3 and the XRD peak intensity of Zr-rich phase which occurred due to the phase separation of Ce0.5Zr0.5O2 phase decreased after adding Ba2+ ions into Ce0.5Zr0.5O2. The specific surface area of the powders increased and the particle size of the powders substantially decreased after the formation of BaZrO3 (Ba content = 1 wt%). It revealed that BaZrO3 could inhibit the occurrence of agglomeration and phase separation of the Ce0.5Zr0.5O2 particles at the same time. However, adding too much barium (> 5 wt%) resulted in the occurrence of agglomeration, which decreased the specific surface area of the powders. The OSC results showed that doping a little amount of barium (0.5~5 wt%) would improve the oxygen storage capacity of the Ce0.5Zr0.5O2. Ce0.5Zr0.5O2 had the maximum OSC performance due to the formation of active oxygen interfaces between Ce0.5Zr0.5O2 and BaZrO3 when the addition of barium increased to 5 wt%.

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