In Situ High Temperature High Pressure MAS NMR Study on the Crystallization of AlPO4-5

详细信息    查看全文

• 作者：Zhenchao Zhao ; Suochang Xu ; Mary Y. Hu ; Xinhe Bao ; Jian Zhi Hu
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：January 28, 2016
• 年：2016
• 卷：120
• 期：3
• 页码：1701-1708
• 全文大小：476K
• ISSN：1932-7455

文摘

A damped oscillating crystallization process of AlPO₄-5 at the presence of small amount of water is demonstrated by in situ high temperature high pressure multinuclear MAS NMR. Crystalline AlPO₄-5 is formed from an intermediate semicrystalline phase via continuous rearrangement of the local structure of amorphous precursor gel. Activated water catalyzes the rearrangement via repeatedly hydrolysis and condensation reaction. Strong interactions between organic template and inorganic species facilitate the ordered rearrangement. During the crystallization process, excess water, phosphate, and aluminums are expelled from the precursor. The oscillating crystallization reflects mass transportation between the solid and liquid phase during the crystallization process. This crystallization process is also applicable to AlPO₄-5 crystallized in the presence of a relatively large amount of water.