Extra-Framework Aluminum Species of Zeolite that Surrogate the Growth of Metal Organic Framework from Zeolite Matrix.

Abstract

Constructing a robust hybrid material with a porous inorganic and a porous organic framework is highly intriguing owing to its diverse functionality and porosity. However, the line of synthesis is not straightforward, since their nucleation and crystal growth processes are incompatible. Here, a simple method for the fabrication of hybrid zeolite/metal-organic framework of different framework structures is developed wherein the less-useful extra-framework aluminum species present in the zeolite surrogate the growth of metal organic framework (MOF) from the zeolite matrix in the presence of organic linkers of the corresponding MOF. An NMR study confirms that all the octahedral Al species are converted to Al-MOF. TGA analysis shows that 32 % Al of H-Beta is converted to Al-MOF. Furthermore, NH3 TPD analysis shows that most of the weak acid sites disappear but strong acid sites are preserved suggesting the utilization of weakly bound Al species of H-Beta in the growth of Al-MOF. The synthesis strategy is successfully demonstrated using H-Beta, H-ZSM-5, and H-Y zeolites for the growth of MIL-53 and MIL-96 MOFs from the zeolite matrix. This synthesis strategy enables application-based engineering of the framework structures, functionality, and porosity of the materials.