Hydrothermal synthesis of zeolitic imidazolate framework-67 (ZIF-67) nanocrystals

Thermally and chemically stable zeolitic imidazolate framework (ZIF) materials have attracted extensive application in gas adsorption and catalysis. Nano-sized ZIF-67 crystals (228 nm) were for the first time synthesized in aqueous solutions at room temperature. As-synthesized crystals were investigated by X-ray diffraction, field-emission scanning electron microscope, thermal gravimetric analysis, gas adsorption measurement. It was found that ZIF-67 nanocrystals were highly stable up to 350 degrees C and could be stable in boiling methanol at least for 5 days. Furthermore, the concentration of reagents plays an important role in controlling particle size, and diluting the synthesis solution can increase the particle size of final products. (C) 2012 Elsevier B.V. All rights reserved.