Journal of Materials Chemistry A
·
2018
·Vol. 6
·期 41
·20100-20109
·
IF 9.931
Xia Shi,Aiping Wu,Haijing Yan,Lin Zhang,Chungui Tian,Lei Wang,Honggang Fu
The rational combination of early-transition metal nitrides (ETMNs) with late-transition metals (LTMs) is a promising method for the design of highly efficient catalysts. Herein, we report the design of Co–Mo2N tubes based on a “MOFs plus MOFs” strategy for efficient electrocatalytic water splitting in 1 M KOH. The 1-D Mo-MOFs (Mo source) were prepared in large quantities by the reaction of imidazole with MoO3. ZIF-67 (Zeolitic Imidazolate Framework-67) (Co source) was then grown on the 1-D Mo-MOFs (Mo-based metal–organic frameworks) to obtain ZIF-67/Mo-MOFs by a solution-phase assembly method. The effective combination is due to the similarity of the ligands in the two MOFs. After nitriding, the ZIF-67 was converted into Co metal, and Mo-MOFs were converted into hollow Mo2N, thus giving a hollow Co–Mo2N hybrid with a Co outer layer on the Mo2N inner core. The ratio of Co and Mo in Co–Mo2N can be easily tuned to give optimized catalysts. The tests indicated that the combination of Co and Mo2N can significantly boost the HER performance of materials. At the current density of 10 mA cm−2, the overpotential (η10) on Co–Mo2N was only 76 mV, which is much lower than 296 mV for Mo2N derived from Mo-MOFs and 180 mV for Co–carbon from ZIF-67. The hybrid has also shown improved OER activity in comparison with Mo2N and Co; therefore, the Co–Mo2N can be used as both anode and cathode for an overall water-splitting cell with η10 of 1.576 V. The improved HER activity can be ascribed to the intimate contact between Co and Mo2N for optimized adsorption on reagents, the tube-like structure for easy mass transfer and the good conductivity of Mo2N, which is favourable for transmitting charge.
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CHROMATOGRAPHIA
·
2019
·Vol. 82
·期 10
·1579-1583
·
IF 1.552
Lou Chunli,Zheng Mengmeng,Xu Yao,Shen Yuting,Kang Jingwu
A sensitive method was developed for detecting 2,2′-azobis(2-amidinopropane) dihydrochloride in polyvinylpyrrolidone by capillary electrophoresis with indirect UV detection. The detection sensitivity was improved significantly using the field-amplified sample injection technique. The background electrolyte was composed of 25 mM imidazole-HCl solution (pH 4.0), in which imidazole acted as the cation probe for the indirect detection at UV 214 nm. Effects of the experimental parameters including pH, the concentration of imidazole as well as the sample injection time on sample preconcentration were investigated and optimized. Under the optimized conditions, baseline separation of 2,2′-azobis(2-amidinopropane) ion with other ions in the polyvinylpyrrolidone samples was achieved within 8 min. The RSD% for the repeatability of the migration time and the peak area were determined as 0.95% and 3.47%, respectively. The limit of detection (LOD, S / N = 3) and the limit of quantitation (LOQ, S / N = 10) were determined as 1.11 × 10 −5 M and 2.77 × 10 −5 M, respectively. The measured recovery at three concentration levels was in the range of 101–104%. This method was successfully applied to detect 2,2′-azobis(2-amidinopropane) in the commercial polyvinylpyrrolidone samples.
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FOOD CHEMISTRY
·
2018
·
IF 4.946
Ying Zhou,Qiyuan Peng,Ling Zhang,Sihua Cheng,Lanting Zeng,Fang Dong,Ziyin Yang
1-Phenylethanol is a chiral flavor compound that has enantiomers, ( R )- and ( S )-1-phenylethanol, with different flavor properties. Given that isolating these enantiomers from plants is low yielding and costly, enzymatic synthesis presents an alternative approach. However, the genes/enzymes that specifically produce ( R )- and ( S )-1-phenylethanol in plants are unknown. To identify these enzymes in tea ( Camellia sinensis ) flowers, 21 short chain dehydrogenase (SDR) genes were isolated from tea flowers, cloned, and functionally characterized. Several recombinant SDRs in Escherichia coli exhibited activity for converting acetophenone to ( S )-1-phenylethanol (CsSPESs, >99.0%), while only one SDR produced ( R )-1-phenylethanol (CsRPES, 98.6%). A pair of homologue enzymes (CsSPES and CsRPES) showed a strong preference for NADPH cofactor, with optimal enzymatic reaction conditions of 45–55 °C and pH 8.0. Identification of the tea flower-derived gene responsible for specific synthesis of ( R )- and ( S )-1-phenylethanolsuggests enzymatic synthesis of enantiopure 1-phenylethanol is possible using a plant-derived gene.
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CARBOHYDRATE POLYMERS
·
2018
·
IF 5.158
Shanshan Ma,Meiyun Zhang,Jingyi Nie,Jiaojun Tan,Bin Yang,Shunxi Song
A biodegradable cellulose-based air filter (Ag-MOFs@CNF@ZIF-8) with multi-layer structure was fabricated by in situ generation of double-component metal-organic frameworks (MOFs) and reinforcement of cellulose nanofiber (CNF). It exhibits good filtration performance, gas adsorption, antibacterial activity and mechanical property. The presence of MOFs could enhance the interaction between the filter and particulate matter (PM) and significantly improve the specific surface area of the composite filter. Thus, the filtration efficiency of the composite filter could reach 94.3% for PM 2.5 and the nitrogen adsorption capacity increased to 109 cm 3 g −1 . Furthermore, the Ag-MOFs@CNF@ZIF-8 filter exhibited excellent antibacterial activity against Escherichia coli with an inhibition zone diameter of 18.1 mm. The compressive strength of the composite filter could be up to 501 kPa, approximately 3.8 times higher than that of pure cellulose filter. Herein, this composite filter has a great application potential in PM 2.5 removal, toxic gas adsorption and healthcare fields.
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Journal of CO2 Utilization
·
2018
·
IF 5.503
Xu Jiang,Faliang Gou,Chenze Qi
A series of C 2 v -symmetric diphenylporphyrin complexes containing a metal ion (Mg, Al, Mn, Fe, Co, Zn) have been synthesized and applied as catalysts for the solvent-free cycloaddition of epoxides and carbon dioxide under atmospheric pressure and mild temperature, in concert with phenyltrimethylammonium tribromide (PTAT) as a co-catalyst. The activity of these catalysts deeply relies on their coordinated metal species. [5,15-Diphenylporphyrin]manganese(III) chloride ( DPP-MnCl ) has been found to be the most effective catalyst under optimal reaction conditions. It's worth mentioning that the cycloaddition of phenyl glycidyl ether (GPE) and CO 2 proceeded successfully by DPP-MnCl /PTAT even at 25 °C and atmospheric pressure. Moreover, preliminary kinetic investigations of this cycloaddition were carried out by using catalysts DPP-MnCl , DPP-CoCl and DPP-Zn , revealing that the (phenoxymethyl)ethylene carbonate (PEC) formation with the lowest activation energy is catalyzed by DPP-MnCl . Furthermore, a Lewis acid-base dual cooperative catalytic mechanism has been carefully proposed in light of the catalyst systems and the experimental results.
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RSC Advances
·
2018
·Vol. 8
·期 21
·11714-11724
·
IF 2.936
Peng Lu,Yong Cao,Xiaolan Wang
A novel catalytic membrane was prepared from polysulfone powders covalently linked with acidic ionic liquids (PSF-ILs), as a heterogeneous catalyst to produce reducing sugar for biomass inulin hydrolysis in a catalytic membrane reactor. However, a complete kinetic model describing the relationship between catalyst physical properties and hydrolysis performance is lacking. The present work attempts to build a hydrolysis kinetic model for the relationship between the conversion and the structure of the PSF-ILs membrane (such as membrane thickness, pore size, porosity and specific surface area). The reaction parameters, such as the reaction time, reaction temperature as well as the nature of the catalyst were of crucial importance in terms of optimal conversion of the biomass inulin to reducing sugar or platform chemicals. The results showed that the structure of the PSF-ILs membrane has a significant effect on its catalytic performance. The PSF-ILs membrane with the best catalytic performance was selected and the maximum TRS yields were up to 100% after two rounds of inulin hydrolysis. The conversions obtained from the established model are in good agreement with the experimental data. Understanding the structure–property relationship of the PSF-ILs membrane will be helpful in designing the physical structure of the membrane to improve its catalytic activity and reusability. Therefore, it is a type of green catalyst with potential application prospects in many catalysis fields.
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JOURNAL OF APPLIED POLYMER SCIENCE
·
2018
·Vol. 135
·期 27
·46421
·
IF 1.901
Xi Yu,Pengfei Yang,Zhiliang Zhang,Liang Wang,Lian Liu,Yongqing Wang
It is a great challenge for self-healing materials to recover their mechanical property and surface hydrophobicity simultaneously after being damaged severely, such as deep and wide surface scratches. In this work, a series of hydrophobic films were prepared by mixing perfluoroalkyl-loaded SiO 2 nanoparticles with thermally self-healing polyurethane. The Diels–Alder reaction of furan groups with bismaleimides endowed the polyurethane with self-healing property, and the introduction of perfluoroalkyl chains gave surface hydrophobicity. When being heated, the low surface energy compounds could gradually move onto the surface to make the surface hydrophobicity recoverable. The self-healing mechanical property and recoverable hydrophobicity would improve the durability and expand the application of polyurethane nanocomposites as self-cleaning and self-healing coatings/surfaces. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 46421.
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ACS Applied Materials & Interfaces
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2013
·
IF 5.008
Yuting Zhang,Yongkun Yang,Wanfu Ma,Jia Guo,Yao Lin,Changchun Wang
A facile approach has been developed to synthesize Fe3O4/PMG (poly (N,N′-methylenebisacrylamide-co-glycidyl methacrylate)) core/shell microspheres using distillation–precipitation polymerization. Treating PMG shell with iminodiacetic acid (IDA) and Ni2+ yields composite microspheres of Fe3O4/PMG/IDA–Ni2+. The Ni2+ ions loaded on the surface of microspheres provide abundant docking sites for immobilization of histidine-tagged proteins. The high saturation magnetization of Fe3O4/PMG (23 emu/g), determined by vibrating sample magnetometer (VSM), allows an easy separation of the microspheres from solution under an external magnetic field. The composite microspheres were used to purify two His-tagged cellulolytic enzymes (Cel48F and Cel9G) directly from crude cell lysates with high binding affinity, capacity, and specificity. The microspheres can be recycled for many times without significant loss of binding capacity to enzymes. The immobilized enzymes on the surface of microspheres well retain their biological activities in degradation of cellulose. These materials show great potential in the biomedical and biotechnological applications that require low-cost purification of recombinant proteins and instant enzyme immobilization at an industrial scale.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2014
·
IF 2.354
Chengcheng Ren,Fang Wang,Zhiqing Zhang,Huihui Nie,Nan Li,Mei Cui
A novel class of Gemini imidazolium surfactants 1,3-bis(3-alkylimidazolium-1-yl) propane bromide [C n -3-C n im]Br 2 ( n = 8, 10, 12) were synthesized and characterized by FT-IR, 1 H NMR and elemental analysis. The surface activity and aggregation behavior of [C n -3-C n im]Br 2 ( n = 8, 10, 12) were investigated by surface tension, conductivity and steady fluorescence methods. A series of surface active parameters, including cmc, Γ max , p C 20 , cmc/ C 20 , A min , γ cmc and Π cmc were obtained from surface tension measurement. It was indicated that Gemini imidazolium surfactants with the longer alkyl chain showed the higher surface activity. The thermodynamic parameters of micellization process, namely, standard Gibbs free energy (Δ G m ο ), enthalpy (Δ H m ο ) and entropy (Δ S m ο ) were derived from conductivity measurement at different temperatures. The micropolarity and the mean aggregation number ( N agg ) of micelles were evaluated from steady fluorescence spectra. The results revealed that the micropolarity and N agg of micelles decreased with the increase of hydrocarbon chain length.
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PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2015
·Vol. 17
·期 8
·5959-5965
·
IF 4.493
Mengshuai Liu,Kunqi Gao,Lin Liang,Fangxiao Wang,Lei Shi,Li Sheng,Jianmin Sun
Catalytic coupling of carbon dioxide with epoxides to obtain cyclic carbonates is an important reaction that has been receiving renewed interest. In this contribution, the cycloaddition reaction in the presence of various hydrogen bond donors (HBDs) catalyzed by hydroxyl/carboxyl task-specific ionic liquids (ILs) is studied in detail. It was found that the activity of ILs could be significantly enhanced in the presence of ethylene glycol (EG), and EG/HEBimBr were the most efficient catalysts for the CO2 cycloaddition to propylene oxide. Moreover, the binary catalysts were also efficiently versatile for the CO2 cycloaddition to less active epoxides such as styrene oxide and cyclohexene oxide. Besides, the minimum energy paths for this hydrogen bond-promoted catalytic reaction were calculated using the density functional theory (DFT) method. The DFT results suggested that the ring-closing reaction was the rate-determining step in the HEBimBr-catalyzed cycloaddition reaction but the EG addition could remarkably reduce its energy barrier as the formation of a hydrogen bond between EG and the oxygen atom of epoxides led this process along the standard SN2 mechanism. As a result, the ring-opening reaction became the rate-determining step in the EG/HEBimBr-catalyzed cycloaddition reaction. The work reported herein helped the understanding and design of catalysts for efficient fixation of CO2 to epoxides via hydrogen bond activation.
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Nature Protocols
·
2014
·Vol. 9
·期 10
·2493-2512
·
IF 7.782
Shao Yanjiao,Guan Yuting,Wang Liren,Qiu Zhongwei,Liu Meizhen,Chen Yuting,Wu Lijuan,Li Yongmei,Ma Xueyun,Liu Mingyao,Li Dali
Conventional embryonic stem cell (ESC)–based gene targeting, zinc-finger nuclease (ZFN) and transcription activator–like effector nuclease (TALEN) technologies are powerful strategies for the generation of genetically modified animals. Recently, the CRISPR/Cas system has emerged as an efficient and convenient alternative to these approaches. We have used the CRISPR/Cas system to generate rat strains that carry mutations in multiple genes through direct injection of RNAs into one-cell embryos, demonstrating the high efficiency of Cas9-mediated gene editing in rats for simultaneous generation of compound gene mutant models. Here we describe a stepwise procedure for the generation of knockout and knock-in rats. This protocol provides guidelines for the selection of genomic targets, synthesis of guide RNAs, design and construction of homologous recombination (HR) template vectors, embryo microinjection, and detection of mutations and insertions in founders or their progeny. The procedure from target design to identification of founders can take as little as 6 weeks, of which <10 d is actual hands-on working time.
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International Journal of Environmental Science and Technology
·
2015
·Vol. 13
·期 1
·113-124
·
IF 2.19
Wang Z.,Ye C.,Wang H.
Amino group exhibits alkaline properties. Amino functionalized imidazole-modified silicas would benefit the adsorption of phenolic compounds. Coupling agent between the silica and the imidazolium ring has an effect on adsorption performance. In this paper, two adsorbents were synthesized for the surface bonding of N -(3-aminopropyl)-imidazole onto silicas modified by 3-chloropropyltriethoxysilane and 3-mercaptopropyltrimethoxysilane, respectively. Infrared spectra, elemental analysis, thermogravimetric analysis and N 2 adsorption–desorption isotherms were used to characterize the two adsorbents, and their adsorption capacities of 2,4-dinitrophenol from aqueous solutions were investigated in detail. The experimental results indicated that amino group plays an important role in the enhancement of adsorption capacities of 2,4-dinitrophenol. The adsorbent with 3-mercaptopropyltrimethoxysilane as coupling agent exhibited lower adsorption capacity due to a weak electron–electron repulsion between the non-bonding electrons of sulfur atom and π electrons of benzene ring of 2,4-dinitrophenol. The adsorption kinetics fitted well with pseudo-second-order model. The two adsorbents could be regenerated and reused eight times at least by washing with HCl. The adsorption mechanism was also discussed.
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