南开大学学报(自然科学版) ›› 2021 ›› Issue (6): 90-.

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晶化后冷却方式诱导形成不同结构的微孔材料(英文)

  

  • 出版日期:2021-12-20 发布日期:2022-01-04

  • Online:2021-12-20 Published:2022-01-04

摘要: An interesting result with the products of crystallization being dominated by the cooling rate has been raised in the crystallization of ethylenediamine (EDA)-directed cobalt phosphates and 1,2-diaminopropane (PDA) -directed zinc phosphates. To explore the reason and mechanism behind this phenomenon,these two systems were crystallized under different temperatures from 1 to 6 d followed by fast cooling (in 10 min) or slow cooling (in 3 h) route, respectively. The results showed that, within a certain range ofcrystallization time, slow cooling rate would result in a framework transformation. Further investigation indicates that this transformation is lower-temperature-preferable in EDA-CoPO4 system, and the slow cooling process give the system a period of time to carry out the transformation under lower temperature. However, in PDA-ZnPO4 system, a higher-temperature-preferable transformation has been found, and further study on SAPO-CHA presents a similar result, which is in consistent with general transformation conditions of most crystals, which protrudes the uniqueness of EDA-directed crystallization of cobalt phosphates systems.

关键词: crystallization, microporous materials, cooling rate, ethylenediamine-CoPO4, 1, 2-diaminopropane-ZnPO4