JOURNAL OF POROUS MATERIALS
·
2020
·Vol. 28
·期 1
·29-38
·
IF 2.183
Yang Shuquan,Wang Yating,Li Huazheng,Zhan Yixing,Ding Xiaoqing,Wang Ming,Wang Xinlong,Xiao Leqin
p -Hydroxybenzoic acid is an emerging contaminant because it has multiple sources such as the hydrolysis of methylparaben, ethylparaben and propylparaben used widely as preservatives in food and drinks, and as well as from the agro-industrial wastewaters. In this study, the nano-ZIF-8@chitosan microspheres (ZIF-8@CSM) were fabricated via the combination of inverse emulsion method and in-situ growth method. The performance of ZIF-8@CSM for the adsorption of p -hydroxybenzoic acid from aqueous solution was studied. The adsorption kinetics showed that the adsorption rapidly reached the equilibrium about 30 s. The equilibrium data were well described by the Langmuir isothermal model and the estimated maximum adsorption capacity was 128.70 mg/g. The thermodynamics analysis indicated negative free energy, enthalpy, and entropy changes suggesting that the adsorption process was spontaneous and exothermic. ZIF-8@CSM is promising to be used as a good adsorption material to remove p -hydroxybenzoic acid rapidly from aqueous solutions.
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Journal of Materials Chemistry C
·
2020
·Vol. 8
·期 22
·7476-7484
·
IF 7.059
Xudong Zhou,Xiaoyun Liu,Zhongkai Cui,Jinlou Gu,Shaoliang Lin,Qixin Zhuang
A new-type of hollow silica@ZIF-8 (HMS@ZIF-8) particle was successfully designed, fabricated and introduced into the fluorinated polybenzoxazole (6FPBO) matrix to prepare the HMS@ZIF-8/6FPBO composite film. Metal–organic frameworks (MOFs) were connected to the surface of hollow silica via covalent bonds, leading to the formation of a shell. Pre-6FPBO prepared from a precursor could be dissolved in organic solvents besides strong corrosive acids, which could protect the filler. HMS@ZIF-8/6FPBO composite films prepared through in situ polymerization and coating exhibited outstanding properties. At both high and room temperatures, the material exhibited excellent dielectric properties. The dielectric constant and dielectric loss decreased down to 2.12 and 0.04, respectively under 1 kHz with the filling of HMS@ZIF-8 particles. HMS@ZIF-8 particles as a filler, evenly dispersed in the matrix, could also improve the tensile modulus of 6FPBO. The tensile modulus of HMS@ZIF-8/6FPBO (6 wt%) increased up to 2.11 GPa, 54% higher than that of the pure 6FPBO matrix. Meanwhile, the composite films demonstrated excellent thermal stability, i.e. the 5% weight loss temperature was higher than 520 °C. This is the first report on MOFs being applied as low dielectric absorbing materials. We believe that the HMS@ZIF-8/6FPBO composite film designed and developed based on this strategy is suitable to be employed in large-scale integrated circuits owing to its excellent dielectric performance, mechanical properties and thermal stability.
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CHINESE JOURNAL OF CATALYSIS
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2020
·
IF 6.146
Pengfei Zhu,Xiaohe Yin,Xinhua Gao,Guohui Dong,Jingkun Xu,Chuanyi Wang
The controlled introduction of oxygen vacancies (OVs) in photocatalysts has been demonstrated to be an efficient approach for improving the separation of photogenerated charge carriers, and thus, for enhancing the photocatalytic performance of photocatalysts. In this study, a two-step calcination method where ZIF-8 was used as the precursor was explored for the synthesis of ZIF-8-derived ZnO nanoparticles with gradient distribution of OVs. Electron paramagnetic resonance measurements indicated that the concentration of OVs in the samples depended on the temperature treatment process. Ultraviolet–visible spectra supported that the two-step calcined samples presented excellent light-harvesting ability in the ultraviolet-to-visible light range. Moreover, it was determined that the two-step calcined samples presented superior photocatalytic performance for the removal of NO , and inhibited the generation of NO 2 . These properties could be attributed to the contribution of the OVs present in the two-step calcined samples to their photocatalytic performance. The electrons confined by the OVs could be transferred to O 2 to generate superoxide radicals, which could oxidize NO to the final product, nitrate. In particular, the NO removal efficiency of Z 350-400 (which was a sample first calcined at 350 °C for 2 h, then at 400 °C for 1 h) was 1.5 and 4.6 times higher than that of Z 400 (which was one-step directly calcined at 400 °C) and commercial ZnO, respectively. These findings suggested that OV-containing metal oxides that derived from metal-organic framework materials hold great promise as highly efficient photocatalysts for the removal of NO.
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CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Boya Qiu,Senqing Fan,Yilin Wang,Jiaojiao Chen,Zeyi Xiao,Yuyang Wang,Yu Chen,Jingyun Liu,Yangmei Qin,Shizhao Jian
A novel catalytic membrane micro-reactor (CMMR) is assembled with ZIF-8 in situ immobilized in polyethersulfone (PES) membrane pores. In this structure, ZIF-8 is evenly distributed on pore walls throughout membrane thickness. The size of ZIF-8 particles is lower than 50 nm. Loading of ZIF-8 can be achieved in the range of 10–180%. This CMMR exhibits high catalytic performance during the Knoevenagel reaction of Benzaldehyde and Ethyl cyanoacetate. The apparent reaction rate constant can be increased by 140.9% at 20 °C, catalyzed by the CMMR than that by ZIF-8 powders under batch catalysis mode. The apparent reaction rate constant can be increased further by 35.9%, with the value being 0.072 ± 0.006 min −1 , if plug-flow reaction mode is adopted. High catalytic stability can be achieved, and this CMMR can be recycled and reused over 10 repeating cycles and 300 min without significant decrease in the conversion rate. The conversion rate is 99.5 ± 0.2% at 80 °C, with loading of ZIF-8 being 85% and the membrane flux being 960 mL m −2 h −1 . Increasing loading of ZIF-8 and temperature can both improve the conversion rate and the apparent reaction rate constant. The apparent activation energy is halved catalyzed by the CMMR than that by ZIF-8 powders.
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MICROPOROUS AND MESOPOROUS MATERIALS
·
2021
·
IF 5.455
Jingjing Zhu,Huaqiang Chen,Lan Wang,Engang Fu,Jianping Wu,Qilei Zhang,Lirong Yang,Gang Xu
A composite hollow mesoporous MIL-101@Pd@ZIF-8-30min (HM-MIL@Pd@ZIF-30min) nanocatalyst with hollow core and stable shell was developed in this study. Hollow mesoporous MIL-101(HM-MIL) was hydrothermally synthesized and employed as the supports of Pd nanoparticles by adopting a facile HM-MIL-template strategy to make ZIF-8 crystals uniformly overgrew on HM-MIL-101@Pd microcrystal cores. The obtained core-shell catalyst possessed hollow mesoporous structure, and the shell layer of ZIF-8 had additional advantages of abundant Lewis basic sites for heterogeneous racemization reaction. Compared with unmodified HM-MIL@Pd and solid MIL-101(Cr)@Pd@ZIF-8 (S-MIL@Pd@ZIF-8), HM-MIL@Pd@ZIF-8-30min had higher racemic chemical activity (conv. 99%) and selectivity (sel. R-amide 94%) in one-pot dynamic kinetic resolution (DKR) reaction system of rac -1-phenethylamine. The catalyst showed excellent stability, and the conversion and selectivity reached 95% and 93% respectively after ten catalytic cycles.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2019
·
IF 4.084
Yongqing Wang,Zhiqiang Lan,Xiantun Huang,Haizhen Liu,Jin Guo
Using a deposition-reduction method, Mg/MOF nanocomposites were prepared as composites of Mg and metal-organic framework materials (MOFs = ZIF-8, ZIF-67 and MOF-74). The addition of MOFs can enhance the hydrogen storage properties of Mg. For example, within 5000 s, 0.6 wt%, 1.2 wt%, 2.7 wt%, 3.7 wt% of hydrogen were released from Mg, Mg/MOF-74, Mg/ZIF-8, Mg/ZIF-67, respectively. Activation energy values of 198.9 kJ mol −1 H 2 , 161.7 kJ mol −1 H 2 , 192.1 kJ mol −1 H 2 were determined for the Mg/ZIF-8, Mg/ZIF-67, Mg/MOF-74 hydrides, which are 6 kJ mol −1 H 2 , 43.2 kJ mol −1 H 2 , and 12.8 kJ mol −1 H 2 lower than that of Mg hydride, respectively. Moreover, the cyclic stability characterizing Mg hydride was significantly improved when adding ZIF-67. The hydrogen storage capacity of the Mg/ZIF-67 nanocomposite remained unchanged, even after 100 cycles of hydrogenation/dehydrogenation. This excellent cyclic stability may have resulted from the core-shell structure of the Mg/ZIF-67 nanocomposite.
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MICROCHIMICA ACTA
·
2019
·Vol. 186
·期 6
·1-8
·
IF 5.479
Li Yufei,Zhang Huanhuan,Cai Xuan,Zhao Hongli,Magdassi Shlomo,Lan Minbo
Two kinds of carbon-based nanozymes were constructed from the same precursor of zeolitic imidazolate framework-8 (ZIF-8) for O 2 •− determination. Hollow carbon cubic nanomaterial (labelled as HCC) was obtained by chemically etching ZIF-8 with tannic acid and a subsequent calcination. A porous carbon cubic nanomaterial (labelled as PCC) was prepared by directly pyrolysis. Then HCC and PCC were immobilized on the surface of screen printed carbon electrodes (SPCE), fabricating HCC and PCC modified electrodes (denoted as HCC/SPCE and PCC/SPCE). HCC/SPCE, best operated at −0.5 V (vs. Ag/AgCl), has a sensitivity of 6.55 × 10 2 nA μM −1 cm −2 with a detection limit of 207 nM (at S/ N = 3) for O 2 •− sensing. And PCC/SPCE, best operated at −0.4 V (vs. Ag/AgCl), exhibited a superior performance for O 2 •− detection with a sensitivity of 1.14 × 10 3 nA μM −1 cm −2 and a low detection limit of 140 nM (at S/ N = 3). The two sensors possess excellent reproducibility and stability. They were used to sense O 2 •− released from HeLa cells.
Illustration of the synthesis of the hollow carbon cubic nanomaterial (HCC) and of the porous carbon cubic nanomaterial (PCC), and the scheme for detection of superoxide anions in HeLa cell.
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PubMed
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2019
·
IF 4.784
Yating Wang,Xiu Dai,Yixing Zhan,Xiaoqing Ding,Ming Wang,Xinlong Wang
The zeolitic imidazole framework (ZIF-8) dotted chitosan (CS) nanocomposites (ZIF-8@CS) were fabricated via in-situ growth method. The morphology, structure and chemical state of ZIF-8@CS were investigated by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transform IR spectroscopy (FTIR) and X-ray diffraction (XRD). The adsorption behavior of ZIF-8@CS composites on Congo Red (CR) in aqueous solution was systematically investigated. The adsorption isotherm data showed that the adsorption of CR by ZIF-8@CS was single-layer adsorption, which was consistent with the Langmuir isotherm model. The maximum adsorption capacity of ZIF-8@CS was 922 mg/g. The kinetics parameters were in accord with pseudo-second-order equation, which implied that the adsorption rate was mainly controlled by the chemisorption mechanism. The removal of CR was attributed to the participation of hydrogen bonds , electrostatic interactions, π-π conjugation and zinc coordination effects.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2019
·
IF 4.175
Yifei Zhan,Jianwu Lan,Jiaojiao Shang,Lin Yang,Xinmei Guan,Wenxu Li,Siqi Chen,Ying Qi,Shaojian Lin
A ZIF-8/Ag/AgCl/TiO 2 modified PAN nanofibrous mat was successfully fabricated via stepwise in-situ growth method. The morphology and composition of the resultant ZIF-8/Ag/AgCl/TiO 2 modified PAN nanofibrous mat were confirmed by emission scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (DRS) and electrochemical impedance spectroscopy (EIS), respectively. Next, methylene blue (MB) was employed as a contaminant to evaluate photocatalytic activity of prepared composite photocatalysts under visible light and natural sunlight irradiation. As expected, the ZIF-8/Ag/AgCl/TiO 2 decorated PAN nanofibrous mat exhibited high photocatalytic activity under both light sources, owing to the synergistic effect among ZIF-8, Ag/AgCl and TiO 2 . The degradation efficiency of the targeted PAN nanofibrous mat under visible light could reach to 98.02% within 120 min towards 20 mL of 50 mg/L MB aqueous solution. Most importantly, the fabricated ZIF-8/Ag/AgCl/TiO 2 modified PAN nanofibrous mat exhibited outstanding recyclability, the corresponding degradation efficiencies were up to 90.16% after five cycles and approximately 80% after ten cycles, respectively. Additionally, the resultant nanofibrous mat showed a long-term stability against acid and alkaline, and excellent antimicrobial performance against S. aureus and E. coli .
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SENSORS AND ACTUATORS B-CHEMICAL
·
2019
·
IF 6.393
Jiahao Wu,Chao Yu,Yujie Yu,Jun Chen,Chengli Zhang,Rufei Gao,Xinyi Mu,Yanqing Geng,Junlin He
A novel dual-mode aptasensor was fabricated for ultra-sensitive detection of microcystin-LR (MC-LR). The direct method was developed using chronoamperometry for quick detection. A glass carbon electrode (GCE) was first modified with MoS 2 -PtPd nanoparticles (NPs). MoS 2 -PtPd was used as a substrate for a higher loading of aptamers and to amplify the signal by catalytic activity toward H 2 O 2 . The aptamer was then assembled onto the modified electrode surface to work as a recognition probe to bind MC-LR. To increase the sensitivity of the aptasensor, we developed an indirect method for ultra-sensitive detection through synthesizing and utilizing novel zeolitic imidazolate framework (ZIF)-8-thionine (Thi)-Au as signal material for the first time. This signal material not only possessed the high conductivity of Au NPs, but also produced current signal from a redox reaction by Thi . The complementary strand of the aptamer was immobilized on the surface of ZIF-8-Thi-Au and their compounds hybridized with the aptamer on the MoS 2 -PtPd modified GCE. MC-LR would replace ZIF-8-Thi-Au compounds by competition binding with the aptamer. The electrical signal would decrease then and be detected by SWV. Under optimal conditions, the linear ranges of the indirect and direct methods were respectively 0.01–50 and 0.1–50 ng mL −1 . And LOD of the indirect and direct method were respectively 0.006 and 0.045 ng mL −1 (signal-to-noise ratio = 3). The aptasensor ensured the accuracy of the detection outcome through comparing the results of the two modes and provided a potentially reliable and ultra-sensitive detection method of MC-LR in water environments.
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CRYSTENGCOMM
·
2018
·Vol. 20
·期 34
·5056-5060
·
IF 3.304
Guangming Li,Xun Wang,Jilin Zhang
An environmentally friendly synthetic route for carbon dots/ZIF-8 fluorescent powders has been developed. It was found that the carbon dots can promote the growth of ZIF-8 crystals. The carbon dots/ZIF-8 fluorescent powders can be fabricated at a relatively low 2-methylimidazole/Zn2+ molar ratio (10 : 1) in aqueous solution at room temperature. Different morphologies and sizes of the carbon dots/ZIF-8 fluorescent powders are easily obtained by adjusting the 2-methylimidazole/Zn2+ molar ratio. The as-prepared carbon dots/ZIF-8 fluorescent powders can afford multi-colored imaging of latent fingerprints on different substrates and show great potential for latent fingerprint detection.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2018
·
IF 5.667
Tianjiao Qi,Xi Yang,Jie Sun
Based on the neck-controlled conduction model of chemiresistive gas sensors, construction of neck-controlled conduction networks in metal oxide films is an efficient method to improve their sensitivity. In this work, we develop a facile route to prepare the neck-connected ZnO (NC-ZnO) films with controllable diameters of the necked part by the sintering of core-shell zeolitic imidazolate framework-8 (ZIF-8)@ZnO films. In order to certify the enhancement of sensitivity by construction of neck-controlled conduction networks, their gas sensing properties towards ethanol are systematically investigated. The results demonstrate that the sensitivity of the optimal NC-ZnO film is dramatically improved, and the response value is about 6-times higher than that of ZnO film, reaching up to 124 ( I g /I a ) towards 50 ppm of ethanol. The results meet our expectation and are in conformity with the neck-controlled conduction model, which further indicates the developed approach in this work is expected to open up a new strategy for the preparation of neck-connected metal oxide films.
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