Formate modulated solvothermal synthesis of ZIF-8 investigated using time-resolved in situ X-ray diffraction and scanning electron microscopy

Cravillon, Janosch; Schröder, Christian; Bux, Helge; Rothkirch, André; Caro, Jürgen; Wiebcke, Michael

doi:10.1039/c1ce06002c

Cited by 309 publications

(295 citation statements)

References 41 publications

Supporting

Mentioning

273

Contrasting

Order By: Relevance

“…2d and e). XRD results showed that new emerging diffraction peaks matched well with the standard diffraction pattern of ZIF-8 powders 19 (ESI-3 †) so that the formed layer indeed belonged to ZIF-8 phase. Moreover, the membrane displayed a strong intensity of the (011) reflection in relation to other reflections, thus indicating a preferred crystal orientation of the (011) planes parallel to the support.…”

supporting

confidence: 54%

MOF membrane synthesis in the confined space of a vertically aligned LDH network

et al. 2014

Self Cite

View full text Add to dashboard Cite

MOF membranes have gained widespread attention due to their unprecedented gas separation performance. Relying on physical interactions, we successfully deposited MOF seeds on a substrate modified with a network of vertically aligned LDH walls before secondary growth of the MOF layer. ZIF-8 membranes thus prepared show considerable H 2 permeance with high H 2 -CH 4 selectivity. This approach is in general suitable for the deposition of nanoparticles on solid surface and their subsequent growth into a dense layer.Metal-organic frameworks (MOFs), a new class of crystalline porous materials, are composed of metal ions or metal oxide clusters coordinated by organic linkers to form highly regular porous networks. Since pioneering works on MOFs (also called coordination polymers) in the 1990s, 1 MOFs have had extensive interest due to their unprecedented opportunities for a wide range of applications in gas storage, purification, catalysis and sensing. 2In particular, the flexibility of pore size and sorption behaviour make them ideal candidates as membranes for gas separation. Our concept is shown in Fig. 1. Prior to seeding, the surface of substrate is segmented into micrometer-sized two-dimensional (2D) compartments by vertically aligned layered double hydroxides (LDHs). LDHs, which have the general formula [M 1Àx, and A nÀ represent di-, tri-valent metal ions and n-valent anions, respectively), are representative of layered compounds. LDHs consist of positively charged brucite-like layers and interlayer galleries containing charge compensating anions. LDHs are selected as ''walls'' between the segments due to their high length-towidth ratio. 15 In particular, we find that MgAl-CO 3 LDH crystallites could be easily in situ grown on porous a-Al 2 O 3 substrate to form LDH networks with diverse microstructures by proper manipulation of Fig. 1 Schematic illustration of the ZIF-8 membrane synthesis in the confined space of a vertically aligned layered double hydroxide (LDH) network illustrating the role of the LDH network: a ''perch'' for the seeds.

show abstract

supporting

confidence: 54%

MOF membrane synthesis in the confined space of a vertically aligned LDH network

et al. 2014

Self Cite

View full text Add to dashboard Cite

show abstract

“…A detailed description of the synthesis and the characterization of the ZIF-8 material obtained may be found in Refs. (Cravillon et al 2012;Bux et al 2009). …”

Section: Methodsmentioning

confidence: 96%

NMR studies of carbon dioxide and methane self-diffusion in ZIF-8 at elevated gas pressures

Pusch¹,

Splith²,

Moschkowitz³

et al. 2012

Adsorption

Self Cite

View full text Add to dashboard Cite

Self-diffusion measurements with methane and carbon dioxide adsorbed in the Zeolitic Imidazolate Framework-8 (ZIF-8) were performed by 1 H and 13 C pulsed field gradient nuclear magnetic resonance (PFG NMR). The experiments were conducted at 298 K and variable pressures of 7 to 15 bar in the gas phase above the ZIF-8 bed. Via known adsorption isotherms these pressures were converted to loadings of the adsorbed molecules. The self-diffusion coefficients of carbon dioxide measured by PFG NMR are found to be independent of loading. They are in good agreement with results from molecular dynamic (MD) simulations and resume the trend previously found by IR microscopy at lower loadings. Methane diffuses in ZIF-8 only slightly slower than carbon dioxide. Its experimentally obtained self-diffusion coefficients are about a factor of two smaller than the corresponding values determined by MD simulations using flexible frameworks.

show abstract

“…Further addition of mim leads to the formation of well-defined single-crystal with twelve hexagon {110} and six rhombic {100} exposed faces. 8 The ligand mim exists in two equivalent tautomeric forms, because the proton can be located on either of the two nitrogen …”

Section: ¹1mentioning

confidence: 99%

Size-controlled Synthesis of Zeolitic Imidazolate Framework-8 (ZIF-8) Crystals in an Aqueous System at Room Temperature

et al. 2012

View full text Add to dashboard Cite

We report here a simple and straightforward method that enables the size-controlled production of zeolitic imidazolate framework-8 in an aqueous system at room temperature. Pure single crystals with the size tuned in the range of ca. 300 nm to 3¯m in mean crystal size can be obtained and exhibit ultrahigh 4 and catalysis. 5 The zirconium(2-methylimidazole) 2 (ZIF-8), with a sodalite (SOD) zeolite-type topology, is a commercially available sample produced by BASF. ZIF-8 possesses large cages of 11.6 ¡ accessible through narrow windows of 3.4 ¡. Most syntheses of ZIFs have been reported so far include using organic solvents such as dimethylformamide (DMF), diethylformamide (DEF), methanol, and DMF/methanol. 6 The use of organic solvents is generally expensive and causes potential environmental pollution and human health problems. Simple techniques to synthesize ZIFs are required for the development of practical applications. Recently, aqueous synthesis of ZIF-8 has been reported. 7 Compared with the synthesis in organic solvents, the aqueous synthesis of ZIFs has particular advantages from economic, operational, and environmental perspectives. However, ZIF-8 prepared in aqueous systems has lower surface area than that prepared in organic systems, suggesting that the product contains dense by-products. 7 In addition, the aqueous synthesis requires excessive imidazole sources to obtain ZIF-8. 7a Further systematic understanding is required to synthesize phase pure ZIF-8 in an aqueous system.In this study, we have developed a simple and sizecontrolled synthesis of ZIF-8 using pure water. We focus on the effects of the imidazole concentration on crystal structure, mean particle size, and particle size distribution.ZIF-8 crystals were prepared from zinc nitrate hexahydrate (Zn(NO 3 ) 2 ¢6H 2 O; Zn) and 2-methylimidazole (mim) in pure water solvent. All chemicals were purchased from SigmaAldrich Chemical Co. and used as received. The molar compositions of the reaction mixtures were in the range of 1 Zn/4100 mim/2228 water. The mim/Zn molar ratio in the precursor solution ranges from 4 to 100. In all runs, to change the mim/Zn molar ratio, only the amount of mim was changed; the amounts of Zn and water were held constant. In a typical preparation, 0.744 g of Zn and 12.3 g of mim were each dissolved in 10 and 90 mL of deionized water, respectively. The former clear solution was poured into the latter clear solution under stirring. All the operations were performed at room temperature. The mixture became cloudy immediately after combining the component solutions. After stirring for 24 h, the milky colloidal dispersion was centrifuged at 6000 rpm for 10 min. The particles obtained were washed with methanol and centrifuged again; the process was repeated five times. The product was dried at 40°C for 48 h under reduced pressure. The products were characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), dynamic light scattering (DLS), thermogravimetric analysis (TGA), and N 2 sorption measurem...

show abstract

Formate modulated solvothermal synthesis of ZIF-8 investigated using time-resolved in situ X-ray diffraction and scanning electron microscopy

Cited by 309 publications

References 41 publications

MOF membrane synthesis in the confined space of a vertically aligned LDH network

MOF membrane synthesis in the confined space of a vertically aligned LDH network

NMR studies of carbon dioxide and methane self-diffusion in ZIF-8 at elevated gas pressures

Size-controlled Synthesis of Zeolitic Imidazolate Framework-8 (ZIF-8) Crystals in an Aqueous System at Room Temperature

Contact Info

Product

Resources

About