Effects of ammonia concentration in hydrothermal treatment on structure and redox properties of cerium zirconium solid solution
来源期刊：JOURNAL OF RARE EARTHS2021年第4期
论文作者：Yunhan Zhang Meisheng Cui Hao Wang Zheng Zhao Liangshi Wang Yongke Hou
摘 要：Cerium zirconium solid solution is a key washcoat material for automotive three-way catalysts（TWCs）.However,improving the redox ability and high temperature thermal stability of cerium zirconium solid solution is still a challenge.In this paper,the cerium zirconium solid solution was prepared by a coprecipitation-hydrothermal method,and the effects of the ammonia concentration on their structures and redox properties were investigated.The results show that when the ammonia concentration is0.8 mol/L,the aged sample（1100 ℃/10 h） of cerium zirconium solid solution has the highest specific surface area of 23.01 m2/g.Additionally,the increase of ammonia concentration improves the uniformity of phase compositions and increases the oxygen vacancies.When the ammonia concentration reaches0.4 mol/L,the cerium zirconium solid solution exhibits the best redox activity,with the lowest reduction temperature of 565℃.Therefore,increasing ammonia concentration in the hydrothermal treatment is beneficial to the thermal stability and redox performance of cerium zirconium solid solution.
Yunhan Zhang1,2,3，Meisheng Cui1,2,3，Hao Wang1,2,4，Zheng Zhao1,2,4，Liangshi Wang1,2，Yongke Hou1,2,4
1. National Engineering Research Center for Rare Earth Materials,GRINM Group Corporation Limited2. Grirem Advanced Materials Co.,Ltd.3. General Research Institute for Nonferrous Metals
摘 要：Cerium zirconium solid solution is a key washcoat material for automotive three-way catalysts（TWCs）.However,improving the redox ability and high temperature thermal stability of cerium zirconium solid solution is still a challenge.In this paper,the cerium zirconium solid solution was prepared by a coprecipitation-hydrothermal method,and the effects of the ammonia concentration on their structures and redox properties were investigated.The results show that when the ammonia concentration is0.8 mol/L,the aged sample（1100 ℃/10 h） of cerium zirconium solid solution has the highest specific surface area of 23.01 m2/g.Additionally,the increase of ammonia concentration improves the uniformity of phase compositions and increases the oxygen vacancies.When the ammonia concentration reaches0.4 mol/L,the cerium zirconium solid solution exhibits the best redox activity,with the lowest reduction temperature of 565℃.Therefore,increasing ammonia concentration in the hydrothermal treatment is beneficial to the thermal stability and redox performance of cerium zirconium solid solution.
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