JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2020
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IF 7.489
Lin Zhong,Hu Zhou,Ruifeng Li,Ting Bian,Sheng Wang,Aihua Yuan
The design and preparation of metal-organic frameworks (MOFs) as self-sacrificed precursors/templates has been considered as a promising strategy in recent years for fabricating metal/carbon electrocatalysts with intriguing architectures and outstanding properties. However, the serious aggregation during the calcination and the poor electron conductivity are still obstacles for these electrocatalysts which need to be urgently solved. Herein, an in situ confinement pyrolysis protocol is reported to transform ZIF-67 nanocrystals on hollow carbon spheres (HCS) to cobalt and nitrogen-enriched carbon shell, resulting in the formation of hierarchical HCS@Co/NC. This is the first study of electrochemistry for HCS decorated with MOFs or MOFs derivatives. In the structure, metallic Co nanoparticles (NPs) and N species are strongly anchored and dispersed in the network of nanocarbon shell, which not only affords a boosting conductivity but also greatly alleviates the aggregation of active sites. Meanwhile, the unique structure with hollow feature provides an effective pathway for mass transport and shortens the transmission path of electrons. Thanks to the advantages of structure and composition , the HCS@Co/NC catalyst exhibits a superb performance of oxygen reduction reaction , which outperforms the commercial Pt/C benchmark.
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高影响因子
JOURNAL OF SOLID STATE CHEMISTRY
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2019
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IF 2.291
Kangling Yin,Huiping Zhang,Ying Yan
A novel microporous ZIF-67 membrane coating on paper-like stainless steel fibers (ZIF-67 membrane/PSSF) was successfully synthesized by a wet layup papermaking-sintering method followed by the seed-induced growth method. The effects of key factors such as crystallization temperature , synthesis time and Hmim/Co 2+ (2-methylimidazole/cobalt chloride) molar ratio on the morphology structure of the samples were studied by the modern characterization techniques including SEM, EDX , TEM, XRD , BET, FTIR and TGA, respectively. The experimental result indicated that the as-synthesized ZIF-67 membrane/PSSF was extremely compact with the average membrane thickness of 4.8 μm. And the sample exhibited high BET surface area (440.9 m 2 /g), uniform pore size (1.881 nm) and large pore volume (0.2096 cm 3 /g). The adsorption breakthrough experiment of toluene was performed on different bed reactors filled with ZIF-67 membrane/PSSF and granular ZSM-5 zeolites , respectively. The experiment data was well fitted by Yoon–Nelson model, where the values of rate constant in the fixed bed with ZIF-67 membrane/PSSF increased by 32.2% compared with that of commercial ZSM-5 zeolites at the flow rate of 100 mL/min. And the bed pressure drop and length of unused bed (LUB) were dramatically reduced by 39.6% and 16.8% in 3 cm ZIF-67 membrane/PSSF fixed bed. In conclusion, mass transfer efficiency was significantly enhanced based the structured ZIF-67 membrane/PSSF fixed bed, and this new material is a promising adsorptive material for VOCs removal.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2019
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IF 6.361
Junxia Guo,Ming Gao,Jun Nie,Fengxiang Yin,Guiping Ma
Metal-organic frameworks (MOFs) derived materials have been used as promising eletrocatalysts. However, the aggregation and poor conductivity are still obstacles for those eletrocatalysts. Herein, an effective method has been developed to overcome this problem by in-situ growth of ZIF-67 nanocrystals on the PAN fibers (ZIF-67/PAN) followed by the pyrolysis of ZIF-67/PAN fiber in 800 °C (ZIF-67/PAN-800). The obtained nanocomposite fibers showed that the isolated metal particles were anchored and linked up by carbon fibers, leading to elevated conductivity, preventing metal particles migration, and increasing stability. Such network structure provides facile pathways for efficient mass transport and shortens the electronic transmission path. As evidences, the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) catalytic tests in this study both showed that ZIF-67/PAN-800 had an excellent bifunctional electrocatalytic activity in alkaline electrolyte . This strategy may give on a new way to synthesis electrocatalytic nanocomposite fibers.
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ACS Sustainable Chemistry & Engineering
·
2017
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IF 5.951
Wenhui Li,Anfeng Zhang,Xiao Jiang,Chen Chen,Zhongmin Liu,Chunshan Song,Xinwen Guo
A Co-based zeolitic imidazolate framework, ZIF-67, has been utilized as a precursor to obtain Co-based porous carbon catalysts. The obtained catalysts display an outstanding catalytic performance toward the CO2 methanation at low temperature. The ZIF-67 crystal morphology can be controlled from cubic to rhombic dodecahedron, and the original particle sizes can be regulated from 150 nm to 1 μm in aqueous solution by cetyltrimethylammonium bromide (CTAB) surfactants. After carbonation in N2 flow, Co-based porous carbon catalysts kept the original ZIF-67 crystal morphology and particle size but differed in the micropore property; the 0.01 wt % CTAB content led to the maximum micropore volume 0.125 cm3/g. The Co nanoparticles inside the carbon matrix range between 7 and 20 nm, and they are separated by the graphite-like carbon avoiding the metal sintering effectively. Furthermore, the catalysts with 0.01% CTAB addition exhibited the highest CO2 conversion (52.5%) and CH4 selectivity (99.2%) under the 72000 mL g–1 h–1 GHSV (gas hourly space velocity) at 270 °C. Noticeably, the Co/PC catalysts performed higher activity and stability than the supported catalysts 20Co/AC. The versatile way offers good prospects for low temperature CO2 methanation and prevents metal sintering effectively.
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CHEMICAL ENGINEERING JOURNAL
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2017
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IF 6.216
Qinghua Wang,Feng Gao,Biyan Xu,Fuxian Cai,Fengping Zhan,Fei Gao,Qingxiang Wang
In this paper, unique amorphous bimetallic sulfides of CoNi 2 S 4 with nanocage structure were synthesized. The ZIF-67 with typical rhombic dodecahedron structure was first synthesized, and then the bimetallic product was achieved by the ingenious combination of Ni 2+ -induced template scarification of the synthesized ZIF-67 and the sulfuration reaction. The characterization assays showed that the CoNi 2 S 4 nanocages perfectly inherited the rhombic dodecahedral morphology of the ZIF-67, but with many vertical aligned nanosheets on the shell. The CoNi 2 S 4 nanocages were utilized as an electrode material for capacitance test. The results revealed that the synthesized CoNi 2 S 4 nanocages have low charge-transfer resistance, and high specific capacitance of 1890 F g −1 at a current density of 4 A g −1 . The specific capacitance remains 89.9% and 71.6%, respectively after 1000 and 5000 cycling charge-discharge measurements. This excellent performance can be ascribed to the amorphous nature, unique hollow nanocage structure and bimetallic composition of the product. Furthermore, an asymmetric supercapacitor was assembled using CoNi 2 S 4 nanocages as positive electrode materials and Yolk-Shell carbon spheres (YS-CS) as negative electrode materials, and the resulting CoNi 2 S 4 //YS-CS device exhibits a high energy density of 35 Wh kg −1 at a power density of 640 W kg −1 .
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JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
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2016
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IF 4.179
Shuaishuai Ding,Chunhua Zhang,Yefei Liu,Hong Jiang,Weihong Xing,Rizhi Chen
We reported a Pd@CN catalyst made of Pd nanoparticles supported on a N-doped carbon derived from ZIF-67. The CN materials with micro/mesoporous structures were well developed for the loading of Pd nanoparticles and improving the catalytic performances. With the increase of calcination temperature of ZIF-67, the BET surface of CN materials initially increased and then reduced. Moreover, the higher calcination temperature would lead to lower nitrogen content in CN materials, causing lower selectivity of phenol hydrogenation to cyclohexanone. Our Pd@CN 600 catalyst achieved a conversion of ca. 95% and a selectivity of ca. 95%, and exhibited excellent stability during recycling experiments.
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WATER ENVIRONMENT RESEARCH
·
2024
·Vol. 96
·期 4
·e11027
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IF 2.5
Yifan Ru,Xianghong Gong,Wangyang Lu,Lu Chen,Lanlan Wei,Qizhou Dai
In this study, we synthesized magnetic MnFe 2 O 4 /ZIF-67 composite catalysts using a straightforward method, yielding catalysts that exhibited outstanding performance in catalyzing the ozonation of vanillin. This exceptional catalytic efficiency arose from the synergistic interplay between MnFe 2 O 4 and ZIF-67. Comprehensive characterization via x-ray photoelectron spectroscopy (XPS), x-ray diffraction (XRD), Fourier transform infrared spectrometer (FT-IR), Brunauer–Emmett–Teller (BET), field emission scanning electron microscopy (FE-SEM), and energy dispersive spectroscopy (EDS) confirmed that the incorporation of MnFe 2 O 4 promoted the creation of oxygen vacancies, resulting in an increased presence of l adsorbed oxygen (O ads ) and the generation of additional ·OH groups on the catalyst surface. Utilizing ZIF-67 as the carrier markedly enhanced the specific surface area of the catalyst, augmenting the exposure of active sites, thus improving the degradation efficiency and reducing the energy consumption. The effects of different experimental parameters (catalyst type, initial vanillin concentration, ozone dosage, initial pH value, and catalyst dosage) were also investigated, and the optimal experimental parameters (300 mg/L1.0-MnFe 2 O 4 /ZIF-67, vanillin concentration = 250 mg/L, O 3 concentration = 12 mg/min, pH = 7) were obtained. The vanillin removal efficiency of MnFe 2 O 4 /ZIF-67 was increased from 74.95% to 99.54% after 30 min of reaction, and the magnetic separation of MnFe 2 O 4 /ZIF-67 was easy to be recycled and stable, and the vanillin removal efficiency of MnFe 2 O 4 /ZIF-67 was only decreased by about 8.92% after 5 cycles. Additionally, we delved into the synergistic effects and catalytic mechanism of the catalysts through kinetic fitting, reactive oxygen quenching experiments, and electron transfer analysis. This multifaceted approach provides a comprehensive understanding of the enhanced ozonation process catalyzed by MnFe 2 O 4 /ZIF-67 composite catalysts, shedding light on their potential applications in advanced oxidation processes. Practitioner Points A stable and recyclable magnetic composite MnFe 2 O 4 /ZIF-67 catalyst was synthesized through a simple method. The synergistic effect and catalytic mechanism of the MnFe 2 O 4 /ZIF-67 catalyst were comprehensively analyzed and discussed. A kinetic model for the catalytic ozone oxidation of vanillin was introduced, providing valuable insights into the reaction dynamics.
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RSC Advances
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2024
·Vol. 14
·期 11
·7528-7539
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IF 3.9
Si Lu,Sasha You,Junhao Hu,Xiang Li,Ling Li
Advanced oxidation processes (AOPs) based on PMS have been used to degrade various refractory pollutants such as drugs, endocrine disruptors, dyes and perfluorinated compounds due to their wide application range, mild reaction conditions, fast reaction rate and simple operation. In this study, tetracycline hydrochloride (TCH) was degraded based on this method. Magnetic MnFe2O4/ZIF-67 nanocomposites were successfully prepared by a hydrothermal method, which combined the magnetic separation characteristics of MnFe2O4 with the high catalytic activity of ZIF-67 and were used to activate peroxymonosulfate (PMS) to efficiently degrade TCH. Satisfactory removal results were obtained with this simple and readily available material, with 82.6% of TCH removed in 15 min. The effect of different conditions on the degradation effect was investigated, and the optimal catalyst concentration and PMS concentration were determined to be 0.1 g L−1 and 0.2 g L−1, respectively, and all had good degradation effects at pH 5 to 10. XPS, impedance test and radical quenching experiments were used to investigate the degradation mechanism. The results showed that sulfate radical (SO4−˙) was the main active species in the degradation process. In addition, the catalyst has good cyclic stability, which provides a new idea for the removal of TCH in wastewater. It is worth mentioning that the catalyst also has good degradation property for other pollutants.
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ACS Applied Nano Materials
·
2024
·
IF 5.3
Yao Liu,Luotian Lv,Han Feng,Hao Liu,Yongqing Wang
Developing highly efficient photocatalysts for CO2 reduction is critical for addressing global warming and energy supply issues. However, both single-component metal-organic frameworks (MOFs) and conventional semiconductor catalysts face significant challenges, such as severe charge recombination, poor CO2 adsorption capacity, and low utilization of solar energy in the photocatalytic reduction of CO2. To address these limitations, the formation of Z-scheme heterojunction photocatalyst has been proved to be an effective way to suppress the recombination of photoinduced carriers. In this work, an indirect Z-scheme heterojunction photocatalytic system, namely, Cu-doped-ZIF-67Co/Bi4O5Br2, is prepared by means of ion-doping and in situ growth strategy. Electrochemical characterization demonstrated the formation of p-type ZIF-67CoCu nanocubes and n-type Bi4O5Br2 nanosheets. The indirect Z-scheme band structure of the heterojunction was well-defined by X-ray photoelectron spectroscopy (XPS), Mott–Schottky test, and ultraviolet photoelectron spectroscopy (UV). The optimal Cu-doping ratio (molar ratio) and composite ratio (mass ratio): 1% ZIF-67CoCu(1:1)/Bi4O5Br2 exhibits excellent photocatalytic CO2 reduction performance, a remarkable rate of 6469.88 μmol·g–1·h–1, and a high CO selectivity of 97%. Compared to individual ZIF-67CoCu and Bi4O5Br2, the performance of reduction of CO2 to CO is improved by 4.19 and 8.64 times, respectively. Density functional theory calculations and in situ diffuse reflectance infrared Fourier transform spectroscopy results had shown that the existence of Cu in ZIF-67 facilitates the desorption of CO and the reduction process features the key CO* intermediate during the photoreduction of CO2 to CO on 1% ZIF-67CoCu/Bi4O5Br2. This study provides an exciting example for the design and understanding of the ion-doped MOFs and the semiconductor construction of indirect Z-scheme photocatalytic system for promoting photocatalytic capacity.
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Surfaces and Interfaces
·
2024
·
IF 5.7
Li Xiao,Shengrui Xu,Yaozong Zhang,Yixin Song,Dapeng Wu,Kai Jiang
Inter-connected zeolite imidazolate framework-67 (ZIF-67) hybrid networks were successfully synthesized by a cellulose nanocrystals (CNCs) mediated spontaneous weaving strategy, which was denoted as ZIF-67@CNC, and was applied to activate peroxymonosulfate (PMS) for Rhodamine B (RhB) degradation. Characterizations results demonstrated that the ZIF-67 nanocrystals are encapsulated within CNCs and subsequently arranged in a string-like configuration. In comparison to pristine ZIF-67, the ZIF-67@CNC catalyst presented superior performances for RhB dye removal both in terms of degradation efficiency and rate, as the kinetic rate constant increased 5.8-fold. This finding was attributed to the improvement in oxygen-containing groups and meso /microporous structures after the introduction of CNCs, leading to efficient binding to compounds and rapid molecular diffusion. Moreover, the ZIF-67@CNC exhibited remarkable stability throughout the catalysis process in aqueous solutions owing to the robust crosslinking between negatively charged CNCs and positively charged cobalt ions , which significantly mitigated the potential secondary pollution of cobalt to the environment. This research opens up new possibilities for the design of highly efficient and durable ZIF-67-based catalysts to promote future wastewater treatment technology.
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Energy Advances
·
2024
·Vol. 3
·期 3
·654-663
·
IF 3.2
Xi Guo,Li Li,Shuo Wang,Huan Zhang,Yuzhen Kuang,Guangbin Duan,Bingqiang Cao
In situ growth of nano-arrays on substrate materials is a neoteric and efficacious catalyst design strategy, but it is still a difficulty to prepare unique nano-structured electrocatalysts with excellent activity for the oxygen evolution reaction (OER). In this study, phosphidizating ternary nickel/iron/cobalt hybrid nano-arrays (NiFeCo-P) with vertically staggered growth were successfully synthesized on the surface of nickel foam (NF) through three steps: impregnation, hydrothermal reaction and phosphidizating calcination. The initial ZIF-67/NF and the derived NiFeCo-layered double hydroxide (LDH)/NF nano-array (NiFeCo-LDH/NF) template promote the charge transfer and ion diffusion between electrolyte surfaces, which is attributed to the enhancement of the interface contact area of electrolyte ions. Phosphidizated NiFeCo-LDH/NF nano-arrays (NiFeCo-P/NF) showed lower overpotential of 251 and 278 mV at 50 mA cm−2 and 100 mA cm−2, respectively. The Tafel slope was 25.24 mV dec−1, which was better than the performance of some transition metal-based OER catalysts reported before. Electrochemical impedance spectroscopy further revealed the good kinetics in the electrolysis process. Furthermore, the high structural stability of the nanosheet array promotes the generation of the active phase in the OER process, so it has good stability after continuous operation for 20 h at a current density of 50 mA cm−2.
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MATERIALS CHEMISTRY AND PHYSICS
·
2025
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IF 4.7
Esraa A. Mansour,Mohamed Taha,Rehab K. Mahmoud,Nabila Shehata,Reda M. Abdelhameed
Nowadays, sulfur compounds (e.g., thiophene) in liquid fuels are increasingly recognized as a major source of air pollution, making fuel purification a top priority. A new composite composed of metal-organic framework (ZIF-67) and ZnFe(4:1)-layer double hydroxide (ZnFe LDH) materials was synthesized at room temperature with varying weight ratios of ZIF-67 (20, 40, and 60 wt %) for the removal of thiophene from a model fuel ( n -heptane). The characterization techniques (XRD, SEM, TEM, FTIR, and BET) confirmed the successful synthesis of the composite materials. The adsorptive desulfurization performance of the ZIF-67@ZnFe LDH composites was compared with ZIF-67 and ZnFe-LDH via adsorption batch processes. The experimental adsorption data were tested using isotherm and kinetic models to know the adsorption process. The composite material (40 % ZIF-67@LDH) appeared a significantly greater adsorption capacity (395.4 mg/g), exceeding that of the two parent materials (ZnFe-LDH and ZIF-67) by (2.5 and 1.6 times), respectively. Monte Carlo simulation was employed to identify the most favorable adsorption sites for thiophene on ZIF-67 and Zn–Fe LDH. Our results suggest that the combination of ZIF-67 and ZnFe LDH in the composite material has a synergistic effect, leading to a remarkable enhancement in adsorption performance. The ZIF-67, with its large pore volume and high surface area, provides a high capacity for thiophene adsorption. While the LDH offers abundant and more favorable interaction sites with higher adsorption energy for thiophene. The 40 % ZIF-67@LDH composite exhibited promising reusability, maintaining its effectiveness for at least four consecutive adsorption-desorption cycles. This suggests its potential as a low cost, efficient and sustainable solution for thiophene removal.
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