RSC Advances
·
2015
·Vol. 6
·期 6
·4695-4704
·
IF 3.84
Jiyong Fang,Yan Wang,Wei Wei,Zheng Chen,Yunxi Li,Zhi Liu,Xigui Yue,Zhenhua Jiang
A nanocomposite consisting of nanoparticles decorated by multi-wall carbon nanotubes (MWCNTs/Ag/Co0.2Fe2.8O4) was designed and synthesized to meet requirements for a wider, thinner, and stronger electromagnetic (EM) wave absorber. The structure and morphology analysis revealed the structure of the nanocomposite absorber. The introduction of Ag nanoparticles can increase the interface by bringing stronger coupling into the heterogeneous nanocomposite, whereas Co0.2Fe2.8O4 can introduce dipoles and magnetic loss as well as additional interfaces into the absorber. The electromagnetic parameters of absorber and wax composite with different absorber contents were measured in the range of 2–18 GHz to evaluate its EM wave attenuation performance. With an absorber loading of 20%, at a low thickness of 1.8 mm, the highest attenuation effectiveness value of −52.4 dB can be achieved at 10.2 GHz. Moreover, with absorber thicknesses from 1.1 to 3.7 mm, RL values below −20 dB can be achieved over a wide frequency range from 4.0 to 18 GHz covering the C band, the X band and the Ku band. Consequently, the nanocomposite absorber has an excellent EM wave attenuation ability with the characteristics of a wide absorption band (4–18 GHz), strong absorption (−52.4 dB) and low absorber thicknesses (1.1–3.7 mm). The excellent EM wave absorbency can be attributed to strong interfacial and dipole polarization, dielectric loss caused by Debye dipolar relaxation and the combination of dielectric loss and magnetic loss. Such a nanocomposite could serve as an attractive candidate for EM wave attenuation applications in the future.
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Journal of Materials Chemistry A
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2016
·Vol. 4
·期 48
·18990-19002
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IF 8.262
Liguang Dou,Hui Zhang
A series of novel hierarchical nanosheet array-like hybrids xCu-LDH/rGO (xCu-LDH: CuxMg3−xAl-layered double hydroxide (x = 0.5, 1.0, and 1.5), rGO: reduced graphene oxide) were assembled via a facile and green aqueous-phase coprecipitation method. Systematic characterization suggests that the hybrids were constructed by hexagonal LDH nanoplates (∼70 nm × 4.5 nm) interdigitated vertical to the surface of single-layer rGO. All the xCu-LDH/rGO hybrids exhibit a remarkable higher activity for catalytic reduction of 4-nitrophenol (4-NP) compared with pure Cu-LDH, commercial Pt/C and other recently reported Cu-related catalysts. These findings were carefully explained by deep study of the catalyst treated with NaBH4, and the xCu-LDH/rGO hybrids as a potential Cu2O reservoir were revealed for the first time. Typically for 1.0Cu-LDH/rGO, a part of Cu2+ ions on LDH layers were instantaneously in situ reduced to well-dispersed ultrafine Cu2O nanoparticles (∼6.8 nm) by NaBH4 in an aqueous reduction system and thus formed relatively strong interaction between Cu2O and LDH/rGO greatly favoring enhanced activity for the reduction of 4-NP, other nitroarenes and organic dyes at room temperature. The excellent activity of the xCu-LDH/rGO hybrids can be attributed to the possible Cu2O–Cu-LDH–rGO three-phase synergistic effect, increased adsorption capacity for reactants via π–π stacking, and unique nanoarray-like morphology of the hybrids. Moreover, the 1.0Cu-LDH/rGO can be cycled for 20 runs without significant loss of activity, giving the hybrid long-term stability.
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RSC Advances
·
2017
·Vol. 7
·期 72
·45545-45551
·
IF 3.108
Shili Liu,Aori Qileng,Junying Huang,Qiongzhi Gao,Yingju Liu
Herein, gold nanoparticles (Au NPs) were decorated on magnetic Fe3O4 nanoclusters@polydopamine nanocomposites (Fe3O4@PDA NCs) through a direct and green reduction method. The morphology was investigated via transmission electronic microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Results showed that Fe3O4 nanoclusters were successfully coated with a PDA shell layer of 25 nm thickness that could work as a reducing reagent to form Au NPs on the surface of Fe3O4@PDA NCs and prevent the aggregation of Au NPs as well. More interestingly, the concentration of the Au precursor had a great effect on both the size and the dispersion of Au NPs on the surface of Fe3O4@PDA NCs, which directly affected the catalytic activity of Fe3O4@PDA@Au. The catalytic performance of Fe3O4@PDA@Au was determined by reducing 4-nitrophenol to 4-aminophenol in the presence of excessive NaBH4, and the result showed that Fe3O4@PDA@Au prepared from a 130 μM Au precursor exhibited the best catalytic activity with the reaction rate constant of 39.2 s−1 g−1 and a conversion of >99% in ten minutes. After being recycled and reused ten times, the magnetic catalyst still had a conversion of >95%; this suggested that it might have practical applications in the reduction of nitroaromatic compounds.
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CHINESE JOURNAL OF CATALYSIS
·
2015
·
IF 1.964
Yongsheng Peng,Wenguang Leng,Bin Dong,Rile Ge,Hongdong Duan,Yan'an Gao
Gold (Au) nanoparticle (NP)-mesoporous silica (SiO 2 ) composite nanotubes were prepared by a bottom-up approach, in which Au NPs were anchored to the inner wall of mesoporous SiO 2 tubular shells. In this composite, the agglomeration, exfoliation, and grain growth of Au NPs were restricted, and the loading and size of the catalyst NPs were easily tuned. The mesoporous shell, open ends, and one-dimensional passage of the SiO 2 nanotubes all promote the diffusion of reactants, which enhanced the catalytic efficiency of this composite in the reduction of 4-nitrophenol. The Au NP-mesoporous SiO 2 composite nanotubes also demonstrated good reusability, and no leaching or agglomeration of the Au NPs was observed during the catalytic reaction .
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JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2015
·Vol. 122
·期 1
·349-358
·
IF 2.042
Yu Guo-Min,Wang Li-Sheng,Sun Jian,Shao Xian-Zhao
A phosphorous flame retardant of phosphoric acid, P, P′-1, 4-phenylene P, P, P′, P′-tetraphenyl ester (PAPTE) was synthesized by diphenyl chlorophosphate and hydroquinone. The structural features of PAPTE were investigated with mass spectrometry, infrared spectroscopy, X-ray powder diffraction and nuclear magnetic resonance methods. The thermal behavior of PAPTE was carried out with thermogravimetric (TG) analysis instruments. The kinetic parameters, including the activation energy and pre-exponential factor of the decomposition process for the title compound, were calculated through the Friedman method, the Kissinger–Akahira–Sunose method and the Flynn–Wall–Ozawa method, while the thermal decomposition mechanism was also studied with the invariant kinetic parameters (IKP) method based on a set of TG data obtained at different heating rates. It was shown that the activation energies calculated for the decomposition reaction by different methods were found to be consistent with the conversion functions calculated by means of the IKP method which depend on a set of kinetic methods.
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BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
·
2015
·
IF 2.297
Li Ma,Xia Gong,Ge Kuang,Rong Jiang,Rongchun Chen,Jingyuan Wan
Sesamin has been described to exert anti-oxidant and anti-inflammatory properties. In present study, we investigated the potential effects and mechanisms of sesamin on lipopolysaccharide (LPS)-induced fulminant hepatic failure (FHF) in d -galactosamine (D-GalN)-sensitized mice. Our results showed that pretreatment with sesamin dose-dependently improved LPS/D-GalN-induced mortality and liver injury as indicated by reduced serum levels of aminotransferases and alleviated pathological damage as well as hepatocyte apoptosis in mice. Additionally, sesamin markedly attenuated LPS/D-GalN-induced adhesion molecules expression, and decreased neutrophils recruitment. Furthermore, sesamin inhibited LPS-induced tumor necrosis factor-alpha (TNF-α) production, p38 mitogen-activated protein kinases (MAPK) and NF-κB activation, and Toll like receptor (TLR) 4 expression in mice and in RAW264.7 macrophage cells. In summary, these results demonstrate that sesamin protects mice from LPS-induced FHF and the molecular mechanisms may down-regulate the expression of TLR4, block MAPK and NF-κB activation, decrease the production of TNF-α.
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PubMed
高影响因子
Scientific Reports
·
2014
·Vol. 4
·期 1
·1-9
·
IF 5.078
Zhong Jie,Xia Zhe,Luo Miao,Zhao Juan,Chen Jie,Wang Liang,Liu Xinsheng,Xue Ding-Jiang,Cheng Yi-Bing,Song Haisheng,Tang Jiang
To obtain high photovoltaic performances for the emerging copper zinc tin sulfide/selenide (CZTSSe) thin film solar cells, much effort has deservedly been placed on CZTSSe phase purification and CZTSSe grain size enhancement. Another highly crucial but less explored factor for device performance is the elemental constitution of CZTSSe surface, which is at the heart of p-n junction where major photogenerated carriers generate and separate. In this work we demonstrate that, despite the well-built phase and large grained films are observed by common phases and morphology characterization (XRD, Raman and SEM), prominent device efficiency variations from short circuited to 6.4% are obtained. Insight study highlights that the surface (0–250 nm) compositions variation results in different bulk defect depths and doping densities in the depletion zone. We propose that suitable sulfurization (at ~10 kPa sulfur pressure) drives optimization of surface constitution by managing the Cu, Zn and Sn diffusion and surface reaction. Therefore, our study reveals that the balance of elemental diffusion and interface reactions is the key to tuning the surface quality CZTSSe film and thus the performance of as resulted devices.
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PubMed
高影响因子
JOURNAL OF SOLID STATE CHEMISTRY
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2015
·
IF 2.133
Yunsheng Liu,Dajiang Mei,Jingli Xu,Yuandong Wu
New alkali metal zinc selenites, A 2 Zn 3 (SeO 3 ) 4 · X H 2 O (A=Li, Na, K; X =2 or 0) were prepared through hydrothermal reactions . Li 2 Zn 3 (SeO 3 ) 4 ·2H 2 O ( 1 ) crystallizes in the monoclinic space group P 2 1 / c with lattice parameters a =8.123(4), b =9.139(4), c =7.938(3) Å, β =112.838(9)°. Na 2 Zn 3 (SeO 3 ) 4 ·2H 2 O ( 2 ) crystallizes in the monoclinic space group C2/c with lattice parameters a =15.7940(18), b =6.5744(8), c =14.6787(17) Å, β =107.396(3)°. K 2 Zn 3 (SeO 3 ) 4 ( 3 ) crystallizes in the monoclinic space group C2/c with lattice parameters a =11.3584(12), b =8.6091(9), c =13.6816(14) Å, β =93.456(2)°. The anionic structures are composed of [Zn 3 O 12 ] 18− sheets, chains, and “isolated” units in compound 1, 2, 3, respectively, and trigonal pyramids SeO 3 2− . The compounds were characterized by the solid state UV–vis–NIR diffuse reflectance spectroscopy , infrared spectra and thermogravimetric analysis .
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RSC Advances
·
2015
·Vol. 5
·期 47
·37710-37715
·
IF 3.84
Fan Yang,Chunxia Wang,Lina Wang,Chao Liu,Andong Feng,Xue Liu,Cheng Chi,Xilai Jia,Liqiang Zhang,Yongfeng Li
We report a simple approach for fabricating flexible, free-standing, catalytic films composed of graphene oxide/carbon nanotube–Au (GO/CNT–Au) composites by using a one-pot chemical reduction route. The catalyst film was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, thermogravimetric analysis and Raman spectroscopy to investigate the morphology, crystalline structure of the composites. The layered structure of the catalyst film is porous, flexible and exhibits excellent catalytic property in the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) reaction. This study demonstrate here for simple yet effective synthesis of catalyst film with a number of advantages such as good strength, high stability, easy operation, and good reusability with minimal loss of activity.
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NEW JOURNAL OF CHEMISTRY
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2014
·Vol. 38
·期 8
·3999-4006
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IF 3.159
Zhenzhen Wang,Shangru Zhai,Bin Zhai,Zuoyi Xiao,Feng Zhang,Qingda An
Novel protocol towards multifunctional magnetic organic–inorganic core–shell nanostructured catalysts of Fe3O4@SN/HPW@CG–Ag with tailored properties are presented in this work. Such nanocomposites congregate the properties and functions of a single component into a whole. For instance, Fe3O4 cores protected by amino-functionalized SiO2 shell endowed the composites with superparamagnetism (28.6 emu g−1) and thereby facilitate the process of separation and recovery. Phosphotungstic acid, as a bridging agent, provided a strong interaction for the anchoring of glutaraldehyde cross-linked chitosan onto the surface of Fe3O4@SN. More interestingly, chitosan could simultaneously behave as a stabilizer and reductant for the in situ synthesis of “green” Ag NPs without addition of any other reducing agent or organic solvent, and Ag NPs provided the compounds with a catalytic performance. Further the size, loading of Ag NPs and the thickness of the chitosan layer were all controllable. Meaningfully, the as-synthesized catalyst Fe3O4@SN/HPW@CG–Ag exhibited an exceptional catalytic performance for the reduction of 4-nitrophenol in the presence of sodium borohydride (the reaction was accomplished within 7 min) and could be reused at least 10 times with good stability by means of convenient magnetic separation. Thence, the design philosophy of the multifunctional robust Ag-based nanocatalysts may pave the way for the synthesis of other catalyst systems with long-term stability.
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CRYSTAL GROWTH & DESIGN
·
2015
·
IF 4.891
Hongling Guo,Yong Cui,Qingwen Tian,Shang Gao,Gang Wang,Daocheng Pan
The Cu2ZnSn(S,Se)4 (CZTSSe) has gained extensive attention in thin film solar cells due to their potential as a nontoxic, low-cost, and earth-abundant absorber material, and a rapid increase in power conversion efficiencies has been demonstrated in laboratory. Compared with the most successful hydrazine-based solution process, the nanocrystal-based ink method and non-hydrazine molecular precursor solution approach are more eco-friendly for fabricating high-efficiency CZTSSe solar cells. However, it is hard to obtain a complete large-grain CZTSSe absorber thin film which can facilitate the transport of photogenerated carriers while minimize grain boundary recombination. Here, we present a simple and effective strategy to significantly enhance grain growth of CZTSSe absorber layers by insetting Sb2S3, CuSbS2, and NaSb5S8 thin films. The incorporation of Sb-based thin films can induce grain growth in the selenization process, and did not produce the impurity phase confirmed by XRD patterns and Raman spectra. It was found that the order of the crystal growth promotion ability is Sb2S3 > CuSbS2 > NaSb5S8 under the same experimental conditions. The presented approach can be extended to other solution processes of fabricating CZTSSe solar cells to enhance their microstructural properties, which are critical for applications in CZTSSe absorbers with fine-grain layers.
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JOURNAL OF MOLECULAR LIQUIDS
·
2024
·
IF 5.3
Fan Luo,Changchao Zhang,Yuyang Zhang,Jie Han,Ziteng Wang,Wenge Yang,Yonghong Hu
4-Hydroxyphenylacetamide (HPAD) is commonly used in the synthesis of high value-added chemicals in the fields of medicine, food and agriculture, such as atenolol, p -hydroxyphenylacetic acid, L -phenylalanine and D -phenylalanine. HPAD relies on chemical synthesis, involving multi-step reactions and multiple chemical catalysts. It is crucial to select appropriate organic solvent to improve yield and purity. In this work, the solubility of HPAD in 12 pure solvents (water, acetonitrile, methanol, ethanol, n-propanol, isopropanol, n-butanol, n-hexane, n-heptane, methyl acetate, ethyl acetate, n-butyl acetate) and 3 binary solvents (n-hexane + methanol, acetonitrile + methanol, n-heptane + methanol) was investigated in the range of 278.15–323.15 K. The solubility of HPAD in the selected solvents was positively correlated with the temperature. Hansen solubility parameters were used to study the dissolution behavior of HPAD. Then, the solvent effect was analyzed by KAT-LSER model, and it was found that the hydrogen bond acidity and nonspecific dipolarity/polarizability of solvents favored the dissolution of HPAD. Moreover, the modified Apelblat model (MA model), λ h model, CNIBS/R-K model (CNK model), Jouyban-Acree model (JA model), and SUN model were used to fit and analyze experimental data. The results showed that the MA model and the CNK model were the best models for single and binary solvents, respectively. Finally, van’t Hoff analysis showed that the dissolution of HPAD in the selected solvents was an endothermic and entropic driven process. This work provided reference data for the separation, purification and crystallization of HPAD, and had certain guiding significance for its industrial production and application.
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