Synthesis of ZIF-11 - Effect of water residues in the solvent onto the phase transition from ZIF-11 to ZIF-7-III

Reif, Benjamin; Fabisch, Florian; Hovestadt, Maximilian; Hartmann, Martin; Schwieger, Wilhelm

doi:10.1016/j.micromeso.2017.02.013

Cited by 16 publications

(16 citation statements)

References 15 publications

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“…Recently, He et al [ 42 ] used cheaper solvent mixture, ethanol‐toluene instead of DEF. Further, it has also been concluded [ 46 ] that water residues, even in small amounts, in the reaction mixture could be the major factor for the formation of ZIF‐7‐III phase impurity in ZIF‐11 synthesized by using Zn (NO 3 ) 2 .6H 2 O and benzimidazole in DEF. Therefore, the controlled crystallization and synthesis of ZIF‐11 framework at room temperature with RHO topology was the major task and carried out by varying different metal salts and temperature/synthetic conditions using benzimidazole as linker.…”

Section: Resultsmentioning

confidence: 99%

“…Mostly uncontrolled phase transformation to ZIF‐7‐III (dense phase) was observed just by employing slight variation in synthetic protocol. [ 46 ] Park et al [ 47 ] described first time the synthesis of ZIF‐11 by interacting Zn (NO 3 ) 2 .4H 2 O with benzimidazole in diethyl formamide (DEF) as a solvent, and later on Seoane and co‐workers [ 48 ] reported a sonochemical method employing a lesser time and temperature. The products however indicated the presence of phase impurity.…”

Section: Resultsmentioning

confidence: 99%

“…Further, it has been noted by using hydrated zinc salt, particularly using zinc nitrate hexahydrate, dense phase ZIF‐7‐III as impurity has been obtained, which is in accordance with the reported results. [ 46 ] AgNPs@ZIF‐11 composites were synthesized by in situ encapsulation of AgNPs in different amounts i.e. 150 μL, 300 μL and 500 μL methanol suspensions (1 mg AgNPs in 2 mL of methanol) during the synthesis of ZIF‐11, and they are abbreviated as AZ1, AZ2 and AZ3, respectively.…”

Section: Resultsmentioning

confidence: 99%

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Facile Synthesis of Metal–Organic Framework (ZIF‐11) and Ag NPs Encapsulated‐ZIF‐11 Composite as an Effective Heterogeneous Catalyst for Photodegradation of Methylene Blue

Chandra

Nath

2020

Applied Organom Chemis

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Facile synthesis of metal–organic framework based on zeolitic imidazolate (ZIF‐11) has been optimized to get a material with rho topology. For the first time AgNPs in various dosing amounts (using 150, 300 and 500 μL of its suspension in methanol) have been successfully encapsulated within ZIF‐11 matrix at room temperature using binary solvent (methanol and toluene) yielding novel multi‐core‐shell AgNPs@ZIF‐11 (AZ1, AZ2 and AZ3) composites. Encapsulation of AgNPs (particle size: 11.76 ± 2.3 nm) has been confirmed by TEM and ultraviolet diffuse reflectance spectroscopic (UV‐DRS) analysis. The lowering of band gap of ZIF‐11 from 4.36 to 4.21 eV indicates the micro‐environment of AgNPs within ZIF‐11 framework, which has also been ensured by XPS analysis. ZIF‐11 and AgNPs@ZIF‐11 composites are highly stable up to 500 °C under air and N2 atmosphere. It has been found that AZ1 composite exhibits excellent photocatalytic activity (almost 100% degradation) toward MB (1.6 mg/L) at pH ≥ 8. Further, various factors such as loading amount of AgNPs (150, 300 and 500 μL suspension in methanol), amount of catalysts (5 mg, 10 mg and 15 mg) and concentration (1.6 mg L−1, 3.19 mg L−1 and 6.38 mg L−1) of methylene blue (MB) dye during photodegradation experiments have been investigated. The capacious achievement of AZ1 composite is its reusability and recyclability; it can be reutilized up to three cycles with the same efficiency (100%) while under fourth and fifth cycle, it can degrade off 92.12% and 72.75% MB, respectively. AgNPs may act as a mediator to promote the quick transfer of photo‐induced electrons and electron–hole pairs separation in ZIF‐11. This work opens a new type of easily fabricated core‐shell composites utilizing ZIF‐11 for wastewater remediation process.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Facile Synthesis of Metal–Organic Framework (ZIF‐11) and Ag NPs Encapsulated‐ZIF‐11 Composite as an Effective Heterogeneous Catalyst for Photodegradation of Methylene Blue

Chandra

Nath

2020

Applied Organom Chemis

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“…The solvent choice plays an essential role in the formation of ZIF-7 phases. As reported by Reif et al [43,44], replacing DMF with anhydrous diethylformamide (DEF) leads to the crystallization of the ZIF-11 phase. The water content in DEF is a very important criterion because even small amounts of H2O (over 0.3 wt.%) lead to product contamination with the ZIF-7-III phase.…”

Section: Introductionmentioning

confidence: 85%

MW Synthesis of ZIF-7. The Effect of Solvent on Particle Size and Hydrogen Sorption Properties

et al. 2020

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We report here fast (15 min) microwave-assisted solvothermal synthesis of zeolitic imidazolate framework material (ZIF-7). We have optimized solvent composition to achieve high porosity and hydrogen capacity and narrow particle size distribution. It was shown that synthesis in N,N-diethylformamide (DEF) results in a layered ZIF-7 III phase, while N,N-dimethylformamide (DMF) as solvent leads to a pure ZIF-7 phase in microwave conditions. A mixture of toluene with DMF allows the production of pure ZIF-7 material only with the triethylamine additive. Obtained materials were comprehensively characterized. We have pointed out that both X-ray diffraction and infrared spectroscopy could be used for the identification of ZIF-7 or ZIF-7 III phases. Although samples obtained in DMF, and in a mixture of DMF, toluene, and triethylamine were assigned to the pure ZIF-7 phase, solvent composition significantly affected the size of particles in the material and nitrogen and hydrogen adsorption process.

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“…Pure ZIF-11 membranes are of special interest because, first, the real potential of ZIF-11 membranes can only be studied on the pure material and, second, porous membranes offer significantly higher fluxes as compared to MMMs. We assume that the synthesis of pure ZIF-11 membranes is mainly hindered by the challenges in synthesis, more specifically, the strong influence of different synthesis parameters in the solvent N , N -diethylformamide, as discussed in our previous papers [ 37 , 38 ]. Therefore, as reviewed above, in most works, ZIF-11 synthesis was carried out in toluene–(m)ethanol mixtures, which is especially efficient for powder synthesis.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of ZIF-11 Membranes: The Influence of Preparation Technique and Support Type

et al. 2021

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Due to its structural features, ZIF-11 is one of the most interesting materials for gas separation applications. Herein, we report a systematic study on the synthesis of ZIF-11 as a supported membrane. For this, we adapted optimized conditions for the ZIF-11 powder synthesis, identified in our previous works, to form ZIF layers on symmetric and asymmetric stainless-steel and asymmetric α-Al2O3 supports. Different techniques were investigated for the challenging layer formation, namely, in situ crystallization (ISC), multiple in situ crystallization (MISC), and the seeding and secondary growth (SSG) method. It was possible to deposit ZIF-11 on different supports by ISC and MISC, although it was difficult to obtain complete layers. SSG, in turn, was more effective in forming dense and well-intergrown ZIF-11 layers. This agrees well with the generally accepted fact that seeding considerably facilitates layer formation. Systematic studies of both individual steps of SSG (seeding and secondary growth) led to a basic understanding of layer formation of ZIF-11 on the different supports. The best membranes prepared by rub seeding and secondary growth achieved Knudsen selectivity. Improved gas separation performance is expected if the formation of defects can be avoided.

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Synthesis of ZIF-11 - Effect of water residues in the solvent onto the phase transition from ZIF-11 to ZIF-7-III

Cited by 16 publications

References 15 publications

Facile Synthesis of Metal–Organic Framework (ZIF‐11) and Ag NPs Encapsulated‐ZIF‐11 Composite as an Effective Heterogeneous Catalyst for Photodegradation of Methylene Blue

Facile Synthesis of Metal–Organic Framework (ZIF‐11) and Ag NPs Encapsulated‐ZIF‐11 Composite as an Effective Heterogeneous Catalyst for Photodegradation of Methylene Blue

MW Synthesis of ZIF-7. The Effect of Solvent on Particle Size and Hydrogen Sorption Properties

Synthesis of ZIF-11 Membranes: The Influence of Preparation Technique and Support Type

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