Details
| Original language | English |
|---|---|
| Pages (from-to) | 2130-2141 |
| Number of pages | 12 |
| Journal | Chemistry of Materials |
| Volume | 23 |
| Issue number | 8 |
| Early online date | 18 Mar 2011 |
| Publication status | Published - 26 Apr 2011 |
Abstract
We report on a simple and straightforward method that enables the rapid room-temperature production of nanocrystals (finely tuned in size between ∼10 and 65 nm) and microcrystals (∼1 μm) of the prototypical microporous zeolitic imidazolate framework (ZIF) material ZIF-8. Control of crystal size is achieved in a novel approach by employing an excess of the bridging bidentate ligand and various simple auxiliary monodentate ligands with different chemical functionalities (carboxylate, N-heterocycle, alkylamine). The function of the monodentate ligands can be understood as a modulation of complex formation and deprotonation equilibria during crystal nucleation and growth. Using time-resolved static light scattering, the functioning of modulating ligands is monitored for the first time by in situ experiments, which offered significant insight into the crystal growth processes. Formation of nanocrystals is characterized by continuous, comparatively slow nucleation and fast crystal growth occurring on a time scale of seconds. Although nucleation and growth are not separated from each other, a significant narrowing of the particle size distribution during early stages results in rather monodisperse nanocrystals, before broadening of the particle size distribution occurs, as observed by complementary ex situ electron microscopy studies. Microcrystal growth is dominated by a particle-monomer addition mechanism, but indications for the operation of a coalescence process during early stages of growth have been also obtained. During later stages of microcrystal growth crystals change their shape from cubes to rhombic dodecahedra. The prepared phase-pure ZIF-8 nanoscale materials exhibit good thermal stability in air and large surface areas, which are comparable to those of large macrocrystals. Nanocrystal powders exhibit dual micro- and mesoporosity.
Keywords
- crystal growth, in situ static light scattering, metal-organic framework, modulated synthesis, nanomaterials, zeolitic imidazolate framework
ASJC Scopus subject areas
- Chemistry(all)
- General Chemistry
- Chemical Engineering(all)
- General Chemical Engineering
- Materials Science(all)
- Materials Chemistry
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In: Chemistry of Materials, Vol. 23, No. 8, 26.04.2011, p. 2130-2141.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Controlling zeolitic imidazolate framework nano- and microcrystal formation
T2 - Insight into crystal growth by time-resolved in situ static light scattering
AU - Cravillon, Janosch
AU - Nayuk, Roman
AU - Springer, Sergej
AU - Feldhoff, Armin
AU - Huber, Klaus
AU - Wiebcke, Michael
PY - 2011/4/26
Y1 - 2011/4/26
N2 - We report on a simple and straightforward method that enables the rapid room-temperature production of nanocrystals (finely tuned in size between ∼10 and 65 nm) and microcrystals (∼1 μm) of the prototypical microporous zeolitic imidazolate framework (ZIF) material ZIF-8. Control of crystal size is achieved in a novel approach by employing an excess of the bridging bidentate ligand and various simple auxiliary monodentate ligands with different chemical functionalities (carboxylate, N-heterocycle, alkylamine). The function of the monodentate ligands can be understood as a modulation of complex formation and deprotonation equilibria during crystal nucleation and growth. Using time-resolved static light scattering, the functioning of modulating ligands is monitored for the first time by in situ experiments, which offered significant insight into the crystal growth processes. Formation of nanocrystals is characterized by continuous, comparatively slow nucleation and fast crystal growth occurring on a time scale of seconds. Although nucleation and growth are not separated from each other, a significant narrowing of the particle size distribution during early stages results in rather monodisperse nanocrystals, before broadening of the particle size distribution occurs, as observed by complementary ex situ electron microscopy studies. Microcrystal growth is dominated by a particle-monomer addition mechanism, but indications for the operation of a coalescence process during early stages of growth have been also obtained. During later stages of microcrystal growth crystals change their shape from cubes to rhombic dodecahedra. The prepared phase-pure ZIF-8 nanoscale materials exhibit good thermal stability in air and large surface areas, which are comparable to those of large macrocrystals. Nanocrystal powders exhibit dual micro- and mesoporosity.
AB - We report on a simple and straightforward method that enables the rapid room-temperature production of nanocrystals (finely tuned in size between ∼10 and 65 nm) and microcrystals (∼1 μm) of the prototypical microporous zeolitic imidazolate framework (ZIF) material ZIF-8. Control of crystal size is achieved in a novel approach by employing an excess of the bridging bidentate ligand and various simple auxiliary monodentate ligands with different chemical functionalities (carboxylate, N-heterocycle, alkylamine). The function of the monodentate ligands can be understood as a modulation of complex formation and deprotonation equilibria during crystal nucleation and growth. Using time-resolved static light scattering, the functioning of modulating ligands is monitored for the first time by in situ experiments, which offered significant insight into the crystal growth processes. Formation of nanocrystals is characterized by continuous, comparatively slow nucleation and fast crystal growth occurring on a time scale of seconds. Although nucleation and growth are not separated from each other, a significant narrowing of the particle size distribution during early stages results in rather monodisperse nanocrystals, before broadening of the particle size distribution occurs, as observed by complementary ex situ electron microscopy studies. Microcrystal growth is dominated by a particle-monomer addition mechanism, but indications for the operation of a coalescence process during early stages of growth have been also obtained. During later stages of microcrystal growth crystals change their shape from cubes to rhombic dodecahedra. The prepared phase-pure ZIF-8 nanoscale materials exhibit good thermal stability in air and large surface areas, which are comparable to those of large macrocrystals. Nanocrystal powders exhibit dual micro- and mesoporosity.
KW - crystal growth
KW - in situ static light scattering
KW - metal-organic framework
KW - modulated synthesis
KW - nanomaterials
KW - zeolitic imidazolate framework
UR - http://www.scopus.com/inward/record.url?scp=79955064221&partnerID=8YFLogxK
U2 - 10.1021/cm103571y
DO - 10.1021/cm103571y
M3 - Article
AN - SCOPUS:79955064221
VL - 23
SP - 2130
EP - 2141
JO - Chemistry of Materials
JF - Chemistry of Materials
SN - 0897-4756
IS - 8
ER -