LANGMUIR
·
2016
·
IF 3.993
Yanhong Liu,Guozhu Li,Runze Qin,Danlei Chen
Mussel-inspired polydopamine (PDA) particles with the size of ∼270 nm are used as a support of palladium (Pd) nanoparticles (NPs) for catalyst preparation. The surface morphology of the PDA particle has been modified via corrosion of CF3COOH. Surface chemistry of the obtained PDA particle has been engineered by the formation of a carboxylic acid-terminated alkanethiol monolayer. The obtained self-assembled monolayer-modified PDA (SAM-PDA) particles are used to load Pd NPs by simply adding H2PdCl4 solution to a suspension of SAM-PDA particles at room temperature. Transmission electron microscopy, energy-dispersive X-ray mapping, dynamic light scattering, X-ray diffraction, X-ray photoelectron spectroscopy, UV–vis, and Fourier transform infrared are used to characterize the catalyst and to investigate the process. Uniform Pd NPs (2–3 nm) have been well-dispersed on the SAM-PDA particles via controllable surface engineering. Surface charges and interactions with a metal ion are regulated by the monolayer of carboxylic acids. The surface chemistry of PDA particles has been finely engineered for efficient loading of noble metal NPs. The obtained Pd/SAM-PDA catalyst has shown greatly increased activity and good reusability compared with Pd/PDA in the reduction of 4-nitrophenol (4-NP) by sodium borohydride or H2. The kinetic data of 4-NP hydrogenation catalyzed by Pd/SAM-PDA are fitted to a Langmuir–Hinshelwood (L–H) model, and the calculated apparent activation energy of this process is 40.77 kJ mol–1.
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APPLIED SURFACE SCIENCE
·
2012
·
IF 2.103
Baolin Zhang,Zhijiang Tu,Fangyuan Zhao,Jun Wang
Superparamagnetic iron oxide nanoparticles were synthesized by thermal decomposition of iron (III) acetylacetonate (Fe(acac) 3 ) in PEG containing poly(vinyl pyrrolidone) (PVP) or poly(ethylene imine) (PEI). The morphologies and phase compositions of the nanoparticles were determined by transmission electron microscopy and X-ray diffraction, respectively. The surface coating of the nanoparticles was recognized using Fourier transform infrared spectroscopy and the presence of the surface coating was confirmed by Thermogravimetric analyses. Magnetic properties were measured using superconducting quantum interference device. The zeta potentials and hydrodynamic sizes of the nanoparticles were determined using nano-particle and zeta potential analyzer. The superparamagnetic iron oxide nanoparticles with sizes from 4.1 nm to 14.9 nm were prepared in the present work, which could be tuned by varying factors such as the reaction temperature, the reaction time, and the PVP or PEI contents. The superparamagnetic nanoparticles were jointly coated with PEG/PVP or PEG/PEI. With hydrodynamic sizes smaller than 40 nm and neutral or positive zeta potentials these superparamagnetic iron oxide nanoparticles exhibited higher dispersion stability in deionized water and in phosphate buffered saline as compared with the superparamagnetic iron oxide nanoparticles coated with PEG alone. This work demonstrates that superparamagnetic iron oxide nanoparticles with modulated properties can be prepared simply by using the improved polyol method.
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高影响因子
JOURNAL OF NANOPARTICLE RESEARCH
·
2015
·Vol. 17
·期 8
·1-7
·
IF 2.184
Huang Yu,Zhan Zhan,Zhang Xiongzhi,Li Houbin,Huang Chi
The composites of anionic spherical polyelectrolyte brushes/conducing polymer (ASPB/CP) have been successfully prepared by chemical oxidative polymerization of aniline and pyrrole monomers in an acidic medium containing anionic spherical polyelectrolyte brushes. These composites were characterized by field emission scanning electron microscopy, transmission electron microscopy, Fourier-transform infrared spectrometry, zeta potentials, X-ray photoelectron spectroscopy, and four probe methods. It was found that the poly(aniline- co -pyrrole) was uniformly coated on the surface of ASPB. Besides, the ASPB/CP composites had higher doping level than the pure copolymer after doping with ASPB. Moreover, these composites also showed better solubility and storage stability than pure copolymer. The electrical conductivity of the ASPB/CP composites at room temperature was 7.2 S/cm, while it was 2.4 S/cm for the pure copolymer under the same circumstances.
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International Journal of Polymer Science
·
2015
·
IF 1.195
Shi-Jia Dong,Bi-Xian Zhang,Yun-Fei Gao,Xiao-Mei Hu
Background and Aims. The complex structure of the lignocelluloses is the main obstacle in the conversion of lignocellulosic biomass into valuable products. Ionic liquids provide the opportunities for their efficient pretreatment for biomass. Therefore, in this work, pretreatment of corn stalk was carried out in ultrasonic-assisted ionic liquid including 1-butyl-3-methylimidazolium chloride [BMIM]Cl, 1-H-3-methylimidazolium chloride [HMIM]Cl, and 1-(1-propylsulfonic)-3-imidazolium chloride [HSO3-pMIM]Cl at 70°C for 2 h. We compared the pretreatments by ionic liquid with and without the addition of deionized water. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were employed to analyze the chemical characteristics of regenerated cellulose-rich materials. Results. [HMIM]Cl and [HSO3-pMIM]Cl were effective in lignin extraction to obtain cellulose-rich materials. FTIR analysis and SEM analysis indicated the effective lignin removal and the reduced crystallinity of cellulose-rich materials. Enzymatic hydrolysis of cellulose-rich materials was performed efficiently. High yields of reducing sugar and glucose were obtained when the corn stalk was pretreated by [HMIM]Cl and [HSO3-pMIM]Cl. Conclusions. Ionic liquids provided the ideal environment for lignin extraction and enzymatic hydrolysis of corn stalk and [HMIM]Cl and [HSO3-pMIM]Cl proved the most efficient ionic liquids. This simple and environmentally acceptable method has a great potential for the preparation of bioethanol for industrial production.
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高影响因子
Analytical Methods
·
2014
·Vol. 6
·期 6
·1753-1758
·
IF 1.938
Yue Zhao,Yongling Du,Daban Lu,Letao Wang,Deyuan Ma,Tianzhen Ju,Menglong Wu
An arginine (Arg) functionalized graphene (Arg-G) nanocomposite was produced successfully and the procedure was environment-friendly. An electrochemical sensor based on the Arg-G nanocomposite was developed for the determination of vanillin. The Arg-G modified glassy carbon electrode (GCE) showed excellent sensitivity properties by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Under the optimized conditions, the oxidation peak current was proportional to vanillin concentration in the range of 2.0 × 10−6 to 7.0 × 10−5 mol L−1 with the correlation coefficient of 0.9986 and the detection limit of 1.0 × 10−6 mol L−1 (S/N = 3). Moreover, the sensor could be used for the detection of vanillin in real food samples with satisfactory results.
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MICROPOROUS AND MESOPOROUS MATERIALS
·
2014
·
IF 3.209
Yuchao Wang,Liyan Zhang,Shengyang Tao,Yonglin An,Changgong Meng,Tao Hu
Composite phase change material (PCM) was prepared by loading pure PCM in the hierarchically porous silica (HPS) matrix. Via the modification by organic silanes, the surface property of the hybrid silica material was effectively controlled. The functional surface groups were not only helpful to reach high loading capacity for PCM (up to 3.5 times of HPS’s weight), but beneficial to enhance the energy storage capacity in confinement. An extra energy increase (about 10% of the total enthalpy value) could be revealed during the phase change process due to the strong van der Waals interaction between modified surface and PCM. The latent heat values of composite PCM (including HPS) could be 163.0 J g −1 . The PCM in modified HPS showed high thermal storage capability (about 99.34% to pure PCM). It was important to study the influence of modified surface on energy storage in confined space. The discussion would be useful to advance high-performance PCM composites.
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高影响因子
CHINESE CHEMICAL LETTERS
·
2013
·
IF 1.21
Cheng Feng,Hai-Yan Zhang,Ning-Zhao Shang,Shu-Tao Gao,Chun Wang
Graphene-Fe 3 O 4 nanocomposite (G-Fe 3 O 4 ) was synthesized by a chemical co-precipitation method which was used as an efficient catalyst for the reduction of nitroarenes with hydrazine hydrate. The method has been applied to a broad range of compounds with different properties and the yields were in the range of 75%–92%. The G-Fe 3 O 4 catalyst can be readily recovered and reused 5 times without significant loss of the catalytic activity.
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高影响因子
RSC Advances
·
2014
·Vol. 4
·期 64
·33866-33873
·
IF 3.708
Zheng-Yong Chen,Hong-Wen Gao,Jia-Xiang Yang
The PEI@Mg2SiO4 hybrid composite is readily synthesized for adsorbing carbon dioxide (CO2) and nitrophenol compounds (NACs), in which more than 11% PEI is embedded. By the removal rate of 4-nitrophenol (10 mg L−1) and the capture capacity of CO2, the Mg2+ : PEI : SiO32− optimal mole ratio of the PEI@Mg2SiO4 is 1 : 0.6 : 1.5. The composite shows the highest adsorption amounts of 0.94 mmol g−1 CO2 at 50 °C. The heat treatment regeneration exhibits a good stability, e.g. the CO2 capture capacity decreases by only 20% after four cycles, and the desorption rate of CO2 remains more than 91%. It also exhibites a fast adsorption and high capacity for 4-nitrophenol (NP), 2,4-dinitrophenol (DNP) and 2,4,6-trinitrophenyl group (TNP). The adsorption capacity of NP, DNP and TNP is 2.40 mmol g−1, 2.66 mmol g−1 and 4.85 mmol g−1 respectively, which is more than that of the conventional sorbents. This work presents the higher capacity and eco–friendly sorbent for CO2 and nitrophenol compounds.
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高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2014
·Vol. 132
·期 16
·
IF 1.64
Li Li,Li-Ru Xia,He-Ye Wang,Xiao-Dong Bi
Bisphenol A based epoxy acrylate (BABEA), a commercial UV-curable material, was introduced as a crosslinker for the fabrication of an epoxy-functionalized monolithic polymer array through UV-initiated copolymerization with glycidyl methacrylate as the functional monomer and poly(ethylene glycol) 200 as the porogen. Scanning electron microscopy images showed that the monolithic poly(bisphenol A based epoxy acrylate- co -glycidyl methacrylate) [poly(BABEA- co -GMA)] exhibited a well-controlled skeletal and well-distributed porous structure. The α-fetoprotein (AFP) immunoaffinity monolithic polymer array prepared by the immobilization of AFP on epoxy-functionalized monolithic arrays was used as an immunosensor for chemiluminescent AFP detection. X-ray photoelectron spectroscopy results indicate that the AFP antibody was successfully immobilized on the monolithic poly(BABEA- co -GMA) array. With a noncompetitive immune-response format, the proposed AFP immunoaffinity array was demonstrated as a low-cost, flexible, homogeneous, and stable array for AFP detection. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132 , 41792.
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高影响因子
JOURNAL OF POWER SOURCES
·
2014
·
IF 5.211
Hongfang Du,Shuang Gu,Rongwei Liu,Chang Ming Li
A novel tungsten diphosphide nanorods (WP 2 NRs) material with good crystallinity is synthesized as an efficient hydrogen evolution reaction (HER) electrocatalyst for the first time through phosphidation of (NH 4 ) 0.25 WO 3 NRs precursor. Towards HER the WP 2 NRs exhibit an onset overpotential of 56 mV, a Tafel slope of 52 mV per decade and an exchange current density of 0.013 mA cm −2 in acidic media. Further, the catalyst only needs overpotentials of 101 and 148 mV to deliver current densities of 2 and 10 mA cm −2 , respectively. In particular, the catalyst can maintain its catalytic activity for 90 h at least, showing good long term operation stability. It also has excellent activity and stability under both neutral and basic conditions. The catalysis mechanism of WP 2 NRs is explored for the fundamental insights.
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ACS Applied Materials & Interfaces
·
2013
·
IF 5.008
Yi Gong,Ai Mei Zhu,Qiu Gen Zhang,Mei Ling Ye,Hai Tao Wang,Qing Lin Liu
Cell encapsulation by locking the interfacial microgels in a water-in-oil Pickering emulsion has currently been attracting intensive attention because of the biofriendly reaction condition. Various kinds of functional microgels can only stabilize an oil-in-water Pickering emulsion, and it is thus difficult to encapsulate cells in the emulsion where the cells are usually dispersed in the continuous phase. Herein, we introduce a facile method for preparing cell-embedded colloidosomes in an oil-in-water emulsion via polyelectrolyte complexation. Escherichia coli (E. coli) was chosen as a model cell and embedded in the thin shell of chitosan/poly(N-isopropylacrylamide-co-acrylic acid) (P(NIPAM-co-AAc)) microcapsules. This is beneficial for expressing cell function because of the little resistance of mass exchange between the embedded cells and the external environment. Cells can be used in biocatalysis or biomedicine and our product will hold great promises to improve the performance in those fields. The synthesis route presents a platform to prepare cell-embedded microcapsules in an oil-in-water Pickering emulsion in a facile and biocompatible way. First, an emulsion stabilized by P(NIPAM-co-AAc) microgels was prepared. Then, the interfacial microgels in the emulsion were locked by chitosan to form colloidosomes. The mechanism of cell encapsulation in this system was studied via fluorescent labeling. The viability of E. coli after encapsulation is ca. 90%. Encapsulated E. coli is able to metabolize glucose from solution, and exhibits a slower rate than free E. coli. This demonstrates a diffusion constraint through the colloidosome shell.
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高影响因子
ACS Synthetic Biology
·
2024
·
IF 3.7
Jiao Feng,Runyuan Jin,Shasha Cheng,Hui Li,Xin Wang,Kequan Chen
In this study, we designed an artificial pathway composed of tyramine β-hydroxylase (TBH) and phenylethanolamine N-methyltransferase (PNMT) for the biosynthesis of both octopamine and synephrine. As most TBH and PNMT originate from eukaryotic animals and plants, the heterologous expression and identification of functional TBH and PNMT are critical for establishing the pathway in mode microorganisms like Escherichia coli. Here, three TBHs were evaluated, and only TBH from Drosophila melanogaster was successfully expressed in the soluble form in E. coli. Its expression was promoted by evaluating the effects of different expression strategies. The specific enzyme activity of TBH was optimized up to 229.50 U·g–1, and the first step in the biosynthetic pathway was successfully established and converted tyramine to synthesize 0.10 g/L of octopamine. Furthermore, the second step to produce synephrine from octopamine was developed by screening PNMT, enhancing enzyme activity, and optimizing reaction conditions, with a maximum synephrine production of 2.02 g/L. Finally, based on the optimization of the reaction conditions for each individual reaction, the one-pot cascade reaction for synthesizing synephrine from tyramine was constructed by combining the TBH and PNMT. The synthetic synephrine reached 30.05 mg/L with tyramine as substrate in the two-step enzyme cascade system. With further optimization and amplification, the titers of octopamine and synephrine were increased to 0.45 and 0.20 g/L, respectively, with tyramine as substrate. This work was the first achievement of the biosynthesis of octopamine and synephrine to date.
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