期刊
JOURNAL OF RARE EARTHS
卷 39, 期 5, 页码 548-557出版社
ELSEVIER
DOI: 10.1016/j.jre.2020.06.018
关键词
SAPO-34; Cerium ions; Low-temperature hydrothermal stability; Surface acidity; Protection mechanism; Rare earths
资金
- National Key RD Program [2017YFC0211302]
- National Natural Science Foundation of China [21676195]
- National Natural Science Foundation for Youth of China [21908207]
By one-pot synthesis of Ce/SAPO-34, the inclusion of Ce enhances the low-temperature hydrothermal stability of the material, maintaining structural and acidic stability. Ce3? at exchange sites on the surface effectively prevents structural collapse.
To probe the function of Ce on enhancing low-temperature stability of SAPO-34, Ce/SAPO-34 with different Ce contents was prepared via one-pot method and further treated at 70 ?C in 80% relative humidity for 24 h. The structural results prove that the one-pot synthesis is an effective way to introduce Ce (Ce < 0.325 wt%) without influencing micro-structural and chemical composition. The lowtemperature hydrothermal stability of Ce/SAPO-34 is enhanced by Ce loading. More than 92% CHA structure and total acidity are maintained over 0.188 wt% Ce/SAPO-34, while only about 20% of that left on pure H/SAPO-34. As Ce exists as Ce3? at exchange sites on the surface of SAPO-34, the results of the linear relationship between protected surface acidity and structure/acidity conservation manifest that Ce3? effectively hinders the structural collapse. This study provides new insight into surface acidity protection for solving the problem of low-temperature hydrothermal stability of SAPO-34. 0 2020 Chinese Society of Rare Earths. Published by Elsevier B.V. All rights reserved.
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