Zeolitic imidazolate frameworks (ZIFs) is a new class of metal-organic
frameworks (MOFs) with zeolite-like properties such as permanent porosity,
uniform pore size, and exceptional thermal and chemical stability. Until recently,
ZIF materials have been mostly synthesized by solvothermal method. In this
thesis, further analysis to tune the size and morphology of ZIF-8 is done upon our
group’s recent success in preparing ZIF-8 crystals in pure aqueous solutions.
Compositional parameters (molar ratio of 2-methylimidazole/Zn2+, type of zinc
salt reagents, reagent concentrations, addition of surfactants) as well as process
parameters (temperature and time) were systematically investigated.
Upon characterizations of as-synthesized samples by X-ray powder
diffraction, thermal gravimetric analysis, N2 adsorption, and field-emission
scanning electron microscope, the results show that the particle size and
morphology of ZIF-8 crystals are extremely sensitive to the compotional
parameters of reagent concentration and addition of surfactants. The particle size
and morphology of hydrothermally synthesized ZIF-8 crystals can be finely tuned;
with the size ranging from 90 nm to 4 μm and the shape from truncated cubic to
rhombic dodecahedron.
Date of Award | May 2012 |
---|
Original language | English (US) |
---|
Awarding Institution | - Physical Sciences and Engineering
|
---|
Supervisor | Zhiping Lai (Supervisor) |
---|
- ZIF-8
- Hydrothermal Synthesis
- Metal-organic frameworks
- Crystal size
- Surfactants
- Crystal morphology