Nanomaterials
·
2018
·Vol. 8
·期 11
·918
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IF 3.504
Dan Tian,Chun-Hui He,Ji-Huan He
Electrospinning is now commercially used for the fabrication of nano/micro fibers. Compared with spider dragline silk, artificial fibers have poor mechanical properties. Unlike natural silk, which has a hierarchical structure with an approximate 3-fold symmetry, the molecular structure of spun fiber has neither folding nor orientation. To date, it is almost impossible to control molecule orientation during the spinning process. Here, we show that macromolecule orientation can be easily controlled using the laminar flow of fluid mechanics. A lasting laminar flow in a long needle can order macromolecules. We find that the orientation of macromolecules can greatly affect the morphology and mechanical properties of fibers. We expect our technology to be helpful for more sophisticated fabrication of fibers with ordered macromolecules and DNA-like twists.Keywords:macromolecule;laminar flow;electrospinning;hierarchical structure
研究领域:
材料科学
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生物物理学
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DOI
PubMed
高影响因子
Catalysts
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2020
·Vol. 10
·期 3
·311
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IF 3.52
Jing Shao,Shuyuan Cheng,Zhaoxu Li,Bichun Huang
A ZSM-5 zeolite with a hierarchical pore structure was synthesized by the desilication-recrystallization method using tetraethyl ammonium hydroxide (TEAOH) and cetyltrimethylammonium bromide (CTAB) as the desilication and structure-directing agents, respectively. The MnOx/ZSM-5 catalyst was synthesized by the ethanol dispersion method and applied for the low-temperature selective catalytic reduction of NOxwith NH3. The results showed that NOxconversion of the hierarchical MnOx/ZSM-5 catalyst could reach 100% at about 120 °C and could be maintained in the temperature range of 120–240 °C with N2selectivity over 90%. Furthermore, the hierarchical MnOx/ZSM-5catalyst presented better SO2resistance performance than the traditional catalyst in the presence of 100 ppm SO2at 120 °C. XRD, SEM, TEM, XPS, BET, NH3-TPD, and TG were applied to characterize the structural properties of the MnOx/ZSM-5 catalysts. These results showed that the MnOx/ZSM-5 catalyst had micropores (0.78 nm) and mesopores (3.2 nm) leading to a larger specific surface area, which improved the mass transfer of reactants and products while reducing the formation of sulfates. The better catalytic performance over hierarchical MnOx/ZSM-5 catalyst could be attributed to the higher concentration of Mn4+and chemisorbed oxygen species and higher surface acidity. The improved SO2resistance was related to the catalyst’s hierarchical pore structure.Keywords:hierarchical pore structure;MnOx/ZSM-5;NH3-SCR;SO2resistance
研究领域:
环境科学
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催化材料
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产品关联
DOI
高影响因子
Catalysts
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2020
·Vol. 10
·期 3
·318
·
IF 3.52
Tian Zhao,Hexin Zhu,Ming Dong
MIL-101(Cr), as a prototypical mesoporous metal–organic framework (MOF), can be facially prepared by involving different modulators to fit various demands. In this paper, a range of MIL-101(Cr) products were prepared under similar conditions. It was found that one of the additives, phenylphosphonic acid (PPOA), could give a stable hierarchical structure material. Compared to other MIL-101(Cr)s, though hierarchical MIL-101(Cr) showed less porosity, it gave a better catalytic performance in the oxidation of indene and 1-dodecene.Keywords:hierarchical MIL-101(Cr);modulators;better catalytic activity
研究领域:
材料科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
Polymers
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2023
·Vol. 15
·期 21
·4215
·
IF 5
Guixiang Chen,Zhenhang He,Zhen Liu,Xin Li,Zhengyin Yao,Peng Zhang
Paper-based thermoelectric (PTE) generators have recently emerged as a green technology that can help alleviate environment pollution and the energy crisis. In this work, a PTE generator was prepared by coating a post-treatment-free thermoelectric ink consisting of poly(3,4-ethylenedioxythiophene)/polystyrene sulfonate (PEDOT:PSS) doped with 1-ethyl-3-methylimidazolium:tricyanomethanide (EMIM:TCM) onto the card paper. By tuning the molar concentration of the EMIM:TCM to 0.17 M and with hot-pressing, the PTE generator showed a decent power factor (PF) value of 6.82 μW m−1K−2, which was higher than the values of PTE in the literature. This phenomenon could be attributed to the synergistic effect of high-performance thermoelectric ink (i.e., PF = 175 μW m−1K−2when deposited on glass slide) and the hot-pressing. The hot-pressing enhanced the packing density of cellulose fibers and the associated PEDOT:PSS hybrid, which enabled the formation of long-range conductive paths. In addition, the PTE had good mechanical stability, indicated by no significant change of the power factor values after cyclic folding 10,000 times. Moreover, the structure of as-prepared PTE could be easily tuned into different shapes that are promising for the preparation of flexible wearable thermoelectric generators.Keywords:paper-based thermoelectric;PEDOT:PSS;hierarchical structure;mechanical stability
研究领域:
材料科学
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能源技术
✓ 已验证
DOI
PubMed
高影响因子
Materials Today Chemistry
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2024
·
IF 6.7
Deshuang Lu,Zhonghan Cheng,Nikom Klomkliang,Wanida Koo-amornpattana,Francis Verpoort,Somboon Chaemchuen
Organic linkers are typically controlled to create the micropore structure when synthesizing metal-organic frameworks (MOFs). However, developing a hierarchical pore structure is beneficial for improving the efficiency of MOFs in various applications. This study investigates a green strategy using a water modulator that competes with the terephthalic ligand to coordinate with zirconium clusters, thereby accessing open sites for hierarchical micro- and mesopores in UiO-66. Using a hydro-modulator induced the formation of a mesoporous structure and enhanced the hydrophilic properties of UiO-66-X due to the presence of hydroxyl groups. Also, model calculations using density functional theory (DFT) support the observed structural chemical geometry. The advantages of a hierarchical pore structure, increased hydrophilicity, and the presence of open sites in the robust structure of UiO-66-X led to a significant enhancement in both antibiotic adsorption and the catalytic activity of ring-opening epoxide reactions compared to the pristine microporous UiO-66. Therefore, utilizing water as a green modulator presents a simple and environmentally friendly approach to introducing hierarchical pore structures in MOFs. It offers a promising strategy for enhancing their performance across various applications.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2018
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IF 2.829
Xiaomei Wang,Xiang Mao,Jianhan Huang
Herein two hierarchical porous hyper-cross-linked polymers modified with phenolic hydroxyl ( OH) groups were synthesized and their adsorption was comparatively evaluated using aniline as the adsorbate. The results reveal that the phenolic OH groups are helpful for the equilibrium adsorption due to the increased polar matching by formation of acid-base complex and hydrogen bonding , and the hierarchical porosity is favorable for the kinetic adsorption because the three dimensional continuous mesopores facilitate the rapid diffusion of aniline. The original aniline solution is optimum for the adsorption and the molecular state of aniline is preferable. The maximum equilibrium capacity is predicted to be 184.8 mg/g by the Langmuir model, and the enthalpy change, Gibbs free energy change , and entropy change are calculated to be negative. The adsorption can reach equilibrium within 60 min, the kinetic data obey the pseudo-second-order rate equation and the first step of the adsorption is mainly controlled by the intra-particle diffusion model.
研究领域:
材料科学
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环境科学
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产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
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2024
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IF 8.4
Jingtong Yu,De Sun,Dongmin Yue,Bingbing Li,Tie Zhu,Peixiang Liu
One of the most promising desalination techniques is photothermal membrane distillation (PhMD). The research focus of PhMD technology is material renewal and structural design. Herein, the CuMOF-PVDF photothermal membranes were designed for PhMD. Firstly, a combination of chemical plating and oxidation was used to generate Cu(OH) 2 nanowires (NWs) onto the PVDF membrane. Then, the ligands were chemically bonded with Cu(OH) 2 NWs to grow the photothermal layer formed by the CuMOF hierarchical structure (CMHS). Under sunlight irradiation, the light was trapped in the CMHS, amplifying absorption and conversion of light. The CuMOF-PVDF membrane with the match-like CMHS absorbed 88.6 % of the light, resulting in a surface temperature of 74.3 °C after 600s. Moreover, by reducing the evaporation enthalpy of water, the performance of the CuMOF photothermal layer was comprehensively improved, realizing a water evaporation rate of 1.55 kg‧m −2 ‧h −1 and a high photothermal conversion rate of 71.4 %. During the PVMD process, the feed solution in the CuMOF photothermal layer was fully heated and supplied to the vaporization area, weakening the temperature polarization. Consequently, the flux of the CuMOF-PVDF membrane was 3.07 kg‧m −2 ‧h −1 and a 99.9 % rejection rate, corresponding to an energy efficiency of 85.2 %. The CuMOF-PVDF membrane is an efficient tool for PhMD, helping to advance desalination technologies.
研究领域:
材料科学
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环境工程
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能源技术
✓ 已验证
产品关联
DOI
高影响因子
Nanomaterials
·
2021
·Vol. 11
·期 9
·2369
·
IF 5.076
Bao Wang,Lihua Kang,Mingyuan Zhu
A hierarchical porous carbon material (HPC) with an ultra-high specific surface area was synthesized with sisal fiber (SF) as a precursor, and then H3PW12O40·24H2O (HPW) was immobilized on the support of SF-HPC by a simple impregnation method. A series characterization technology approved that the obtained SF-HPC had a high surface area of 3152.46 m2g−1with micropores and macropores. HPW was well-dispersed on the surface of the SF-HPC support, which reduced the loading of HPW to as low as 5%. HPW/SF-HPW showed excellent catalytic performance for oxidative desulfurization, and the desulfurization rate reached almost 100% under the optimal reaction conditions. The desulfurization rate of HPW/SF-HPW could be maintained at above 94% after four recycles.Keywords:oxidative desulfurization;hierarchical porous carbon;HPW loading;dispersion
研究领域:
材料科学
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催化化学
✓ 已验证
DOI
PubMed
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
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2018
·
IF 5.667
Ding Wang,Kechuang Wan,Minglu Zhang,Huijun Li,Ping Wang,Xianying Wang,Junhe Yang
SnO 2 nanofiber/nanosheets with hierarchical nanostructures were successfully synthesized via a facile hydrothermal method by using hollow SnO 2 nanofibers as the backbone. The microstructure, morphology, chemical composition, oxidation states and surface areas of SnO 2 nanofibers, SnO 2 nanofiber/nanosheets and SnO 2 nanosheets were comparatively studied by X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), Transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller (BET). The characterization results indicated that the hierarchical SnO 2 nanofiber/nanosheets were constructed by nanosheets arrays uniform growth on the surface of nanofibers. Sensing performances of SnO 2 -based nanomaterials were investigated utilizing formaldehyde (HCHO) as a target gas. Compared to SnO 2 nanofibers, nanosheets and the physical mixture of nanofibers and nanosheets, the gas sensor based on SnO 2 nanofiber/nanosheets exhibited better response, more excellent selectivity, transient response and trace detection ability to HCHO gas. The response (R a /R g ) of the gas sensor is 57 toward 100 ppm HCHO at 120 °C, which is about 300% and 200% higher than that of pure SnO 2 nanofibers sensors and SnO 2 nanosheets sensors, respectively. Furthermore, the sensor has an excellent response/recovery performance with 4.7 s and 11.6 s for detecting 100 ppm HCHO. Both the growth process and the gas sensing mechanism of SnO 2 hierarchical nanostructures were discussed. Successful preparation of SnO 2 nanofiber/nanosheets is attributed to uniform decoration of seeds on the nanofibers and suitable growth conditions of nanosheets. Enhanced sensing performance mainly result from the synergistic effect of nanofibers and nanosheets, hierarchical structures and larger specific surface areas. The synthetic strategy can also be applied in preparing hierarchical materials of different constituent materials.
研究领域:
材料科学
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传感器技术
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环境监测
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DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
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2019
·
IF 4.182
Aihu Feng,Yang Yu,Le Mi,Yunzhen Cao,Yun Yu,Lixin Song
In this work, the hierarchical Y zeolites are firstly obtained by etching NaY zeolites with different NH 4 HF 2 solutions. The morphology and microstructure, toluene adsorption property of as-prepared hierarchical Y zeolites are characterized. The results demonstrate that the mesoporous number and size, the n(SiO 2 )/n(Al 2 O 3 ) value of hierarchical Y are increased with NH 4 HF 2 concentration. The 0.3M NH 4 HF 2 -etched NaY exhibits satisfactory crystallinity, suitable mesoporous content and better toluene adsorption performance. The NH 4 HF 2 -etched NaY is an excellent material for pressure swing adsorption. Furthermore, the synthesis mechanism of hierarchical Y has been elaborately demonstrated. The synergistic effect of H + and F − is beneficial to dealumination as well as the introduction of mesoporous. The NH 4 HF 2 ionizes into positive H + and negative F − at a very slow rate, which avoids the concentration of H + and F − going up suddenly. Under the circumstances, the dealumination reaction between NH 4 HF 2 and NaY zeolites is more sustained and mild, and the crystallinity of hierarchical Y zeolites is higher than that of the HCl/NH 4 F-etched or HF/NH 4 F-etched NaY. This work presents an effective method to synthesize the hierarchical Y zeolites.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
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2022
·
IF 6.449
Shaoqing Wang,Zhihe Li,Weiming Yi,Peng Fu,Xueyuan Bai
Catalytic pyrolysis of corn cob lignin were preformed using a tailored HZSM-5 @Al-SBA-15 hierarchical zeolite for the production of value-added aromatic hydrocarbon. Resulted showed that the highly ordered two-dimensional p6mm mesoporous shell could uniformly form on the surface of HZSM-5 core phase. The porosity and acidity of the HZSM-5 @Al-SBA-15 could be tailored by adjusting the TEOS/HZSM-5 mass ratio in the synthesis process. The aromatic hydrocarbon components regulated due to pre-cracking and enhanced diffusion via the mesoporous shell, as well as the retained shape-selectivity of the HZSM-5 core. Herein, the relative content of MAHs reached 45.02% with fewer poly-aromatic hydrocarbons (PAHs) of 25.91% when the TEOS/HZSM-5 mass ratio of 1.0. However, the length of the diffusion path had a certain impact on the anti-coking behavior. The catalytic stability of the hierarchical zeolites was also improved, with less coke formation than HZSM-5 alone. This work demonstrates that using a tailored hierarchical zeolite to regulate aromatic hydrocarbon components is feasible, and provide a reference for the practical application of agricultural crop wastes.
研究领域:
能源与环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2023
·
IF 4.2
Xiaomi Meng,Zhongde Dai,Charles Q Jia,Lin Yang,Wenju Jiang,Lu Yao,Qiying Zhou,Bo Xu
In this study, FAULSP(n)/MOF-199 composites with hierarchical porous structures have been synthesized by zeolite-induced in situ growth of MOF-199 and applied for efficient adsorption of toluene and acetone. The results revealed that the presence of FAULSP triggered morphology evolution and developed new structural defects of MOF-199 due to the coordination of FAULSP and the linker, resulting in a hierarchical porous structure of FAULSP(n)/MOF-199. The SBET of FAULSP(n)/MOF-199 ranged from 1013 to 1344 cm2 g–1, comparable to or even superior to that of MOF-199 (1035 cm2 g–1). FAULSP(n)/MOF-199 had more developed mesoporous structures (Vmes), increased from 0.027 cm3 g–1 of MOF-199 to 0.354 cm3 g–1 of FAULSP(15)/MOF-199. The integrated surface chemistry coupled with the derived hierarchical porous structure provided FAULSP(n)/MOF-199 a good adsorption property of both weakly polar toluene and strongly polar acetone. The FAULSP(4)/MOF-199 showed the best adsorption performance with saturated adsorption capacities of 430.2 and 311.1 mg g–1 of toluene and acetone at 25 °C and 1000 mg m–3. The FAULSP(n)/MOF-199 also exhibited excellent adsorption–desorption stability, with only 4.55 and 8.05% capacity loss of toluene and acetone after five adsorption–desorption cycles. According to the characterization before and after adsorption, the kinetic and thermodynamic studies knew that the adsorption of toluene and acetone on FAULSP(n)/MOF-199 was mostly a physical-adsorption process, in which both monolayer and multilayer adsorption coexisted.
研究领域:
材料科学
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环境科学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）