Nature of cerium on improving low-temperature hydrothermal stability of SAPO-34

• 作者: Qingyun Wang Meiqing Shen Jianqiang Wang Chen Wang Jun Wang
• 来源期刊: 稀土学报（英文版）
• 年，卷（期）: 2021,（5）
• 所属期刊栏目: RARE EARTH CATALYSIS
• 页码范围: 548-557
• 页数: 10页
• 语种: 英文

摘要

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 ℃ 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 low-temperature 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.