Facile synthesis of aluminum-based metal-organic frameworks with different morphologies and structures through an OH(-)-assisted method

Chem Asian J. 2013 Aug;8(8):1873-8. doi: 10.1002/asia.201300135. Epub 2013 May 24.

Abstract

We report the facile synthesis of aluminum-based metal-organic frameworks (MOFs) with different morphologies and structures by tuning the OH(-) content in the reaction solution. MIL-96 crystals with dodecahedral and hexagonal column shapes were successfully synthesized by tuning the OH(-) ion content of the synthesis solution. When the OH(-) ion content was further increased, MIL-110 with a nanorod morphology appeared as the product. For the first time, we obtained pure MIL-96 and MIL-110 under basic conditions directly by using the 1,3,5-benzenetricarboxylic acid (btc) linker. All samples show significant thermal stability, with a decomposition temperature above 300 °C. We found that the gas adsorption properties of MIL-96 were directly dominated by the crystal morphology. At 0.4 °C and 30 bar, the dodecahedral and hexagonal MIL-96 samples can adsorb 9.3 and 6.5 mmol g(-1) CO2, respectively, although they possess similar surface areas and identical crystalline structures. The MIL-110 nanorod shows a CO2 adsorption capacity of up to 16 mmol g(-1) under the same conditions.

Keywords: crystal engineering; gas adsorption; metal-organic frameworks; structure elucidation.