A groundbreaking study has introduced DNL-17, a newly synthesized aluminophosphate molecular sieve with a unique porous structure.
Researchers leveraged advanced 3D electron diffraction to reveal its intricate crystallographic details and discovered a novel structure-directing mechanism. This advancement paves the way for enhanced molecular sieve design with promising industrial applications.
Unlocking the Potential of Aluminophosphate Molecular Sieves
Aluminophosphate (AlPO) molecular sieves are crystalline, microporous materials composed of alternating PO4 and AlO4 tetrahedra. These structures create well-organized channels and cage-like frameworks.
Small-pore AlPO molecular sieves with three-dimensional (3D) channel systems have significant potential for selective adsorption and energy storage. However, synthesizing these materials and determining their precise crystallographic structures remains a challenge.
A Breakthrough in Synthesis: Introducing DNL-17
In a study published in the Journal of the American Chemical Society, a research team led by Prof. Peng Guo and Prof. Zhongmin Liu from the Dalian Institute of Chemical Physics at the Chinese Academy of Sciences successfully synthesized a novel small-pore AlPO molecular sieve, named DNL-17. They achieved this using a flexible diquaternary ammonium compound as an organic structure-directing agent (OSDA).
Researchers used cutting-edge 3D electron diffraction (ED) technology to directly determine the complex crystallographic structure of DNL-17. This new member of the ABC-6 family features 3D 8 * 8 * 8-ring pores and a framework structure containing four characteristic cages (d6r, can, eri, and cha), with a distinct 24-layer stacking sequence along the c axis (AABAACAABBCBBABBCCACCBCC).
A Unique Structure-Directing Effect
In addition, researchers identified a unique structure-directing effect in which the flexible OSDAs adopt various conformations to stabilize different cages during crystallization. They demonstrated that DNL-17 shows promise for selective adsorption in the separation of n-butane and isobutane.
“This study demonstrates that OSDAs can construct novel AlPO MSs through different conformations, paving the way for the design and synthesis of new molecular sieves,” said Prof. Guo.
Reference: “DNL-17: A Small-Pore Aluminophosphate in ABC-6 Family with 24 Stacking Layers Unraveled by Three-Dimensional Electron Diffraction” by Chenyang Nie, Yuanhao Li, Xiaona Liu, Nana Yan, Chao Ma, Jiahui Zhu, Linlin Hao, Peng Guo and Zhongmin Liu, 31 January 2025, Journal of the American Chemical Society.
DOI: 10.1021/jacs.4c18190
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