查找使用阿拉丁产品的科研文献

Highly reactive N,N′-carbonyldiimidazole-tailored bifunctional electrocatalyst for oxygen reduction and oxygen evolution

Wen-Li Xin,Kun-Kun Lu,Dun-Ru Zhu,Hai-Bo Zeng,Xue-Ji Zhang,Robert-S. Marks,Dan Shan

The rational design and synthesis of an efficient bielectrocatalyst for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) by tuning the chemical composition , structure and the catalytic sites of the hybrid materials is always of a great challenge. In this work, an innovative strategy based on the highly active N,N′-carbonyldiimidazole (CDI) is described to one-pot synthesis of a novel precursor for bifunctional O 2- electrocatalyst . The coordination of Co 2+ with the in situ generated ligands imidazole and carbonate results in ultrafine cobalt carbonate (CoCO 3 )-involved cobalt-based zeolitic imidazole framework (CoCO 3 /Co-ZIF). Owing to the presence of ultrafine CoCO 3 , carbonization of CoCO 3 /Co-ZIF at 800 °C under N 2 atmosphere endows the pyrolysis product with a special skeleton of carbon nanotube (CNT)-tipped end CoO x , multivalent CoO x wrapped in graphitic carbon layers. Thus, the resulting CoO x /Co-N-C exhibits the enhanced and durable ORR/OER performance in alkaline media, due to the fast electron and mass transfers. For ORR, a large limiting current density of 4.59 mA cm −2 can be obtained by CoOx/Co-N-C, which is comparable to that of Pt/C. For OER, it only needs an over potential of 1.65 V to achieve a current density of 10 mA cm −2 , merely 30 mV behind IrO 2 (1.62 V).

The effect of N-ethyl-N-hydroxyethyl perfluorooctanoamide on wettability alteration of shale reservoir

Li Yongfei,Wang Yanling,Wang Kun,Gomado Foster,Wang Gangxiao,Tang Longhao,Rong Xufeng

The wettability of the formation is critical for the flow back of the fracturing fluid and can further affect the gas production. So it is very necessary to study the wettability of shale reservoir. Here, a novel fluorocarbon surfactant, N-ethyl-N-hydroxyethyl perfluorooctanoamide, was synthesized and characterized by different methods. the contact angles of water and n-decane on the shale increased from 36° and 0° to 121° and 105°, respectively, after treated by N-ethyl-N-hydroxyethyl perfluorooctanoamide (0.5 wt.%). The surface free energy reduced from 72 mN/m to 7.4 mN/m. The results agreed with that of imbibition and capillary tube rise test. Additionally, the analysis of scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) showed that the roughness of shale surface remarkably increased. These results fully proved that the shale wettability is changed to super gas-wetting. Besides, the thermal analysis revealed that the novel fluorocarbon surfactant has good thermal stability. This indicates that it can be better applied to reservoir modifications at higher temperatures.

Spectrophotometric determination of trace permanganate in water with N,N-diethyl-p-phenylenediamine (DPD)

Xin Liu,Huahua Cai,Jing Zou,Zijun Pang,Baoling Yuan,Zhenming Zhou,Qingfeng Cheng

A sensitive spectrophotometric method (the N,N -diethyl- p -phenylenediamine (DPD) method) was established for the determination of trace permanganate concentration (0–10 μM) in water. The DPD method was based on the oxidative coloration reaction where permanganate could oxidize DPD to form the red colored DPD radical (DPD • + ) with a second-order rate constant of 2.96 × 10 4  M −1  s −1 at pH 6 (50 mM phosphate buffer). The generated DPD • + could be quantitatively measured at 551 nm using an UV–Vis spectrophotometer. There was a good linear relationship (R 2  = 0.999) between the absorbance of DPD • + and permanganate concentration. The DPD method was highly sensitive, and the absorbance of generated DPD • + at 551 nm was as high as 5.70 × 10 4  cm −1 per M (mol L −1 ) of permanganate. The reaction of permanganate with DPD in the pH range of 4.0–8.0 had a stoichiometric coefficient of 1:2.71. The residual absorbance of DPD •+ in ultrapure water and natural waters was fairly stable for 30 min. Limits of detection of the proposed DPD method in ultrapure water and natural waters were calculated to be as low as 0.010 μM and 0.017 μM, respectively. Moreover, trace permanganate concentrations of 0.04 and 0.10 μM were found in natural waters and wastewater by the proposed DPD method. Additionally, the DPD method could be applied to measure the second-order rate constants of the reaction of permanganate with phenol at pH 7.0 (28.2 M −1  s −1 ).

CO2 responsive wormlike micelles based on sodium oleate, potassium chloride and N,N-dimethylethanolamine

Jinyu Wang,Dongfang Liu,Zhiyu Huang,Cunchuan Zheng

Design, synthesis, bioactivity and action mechanism of N-substituted N′-phenylpicolinohydrazides against phytopathogenic fungi

Zhang Yuhao,Bai Ruofei,Du Tengyi,Wang Yiwei,Zhou Bohang,Zhou Congwei,Zhou Le

N ′-phenylpicolinohydrazide has been proven to be a promising lead compound for research and development of novel fungicides for agriculture in our previous study. As our continuing research, in this study, a series of N -substituted derivatives of N ′-phenylpicolinohydrazide were synthesized and explored for the inhibition activity on nine phytopathogenic fungi and action mechanism. The results found that eleven of the compounds had excellent antifungal activity with more than 80% inhibition rates at 50 µ g/mL on part or most of the fungi, especially A. solani and P. piricola . Compounds 5i , 5j and 5k showed EC 50 values of < 8.0 µg/mL against A. solani superior to positive control carbendazim (EC 50  = 36.0 µg/mL) while 5p and 5q exhibited the highest activity with EC 50 values of 2.72 and 2.80 µg/mL against P. piricola superior to positive control boscalid (EC 50  > 50.0 µg/mL). Furthermore, 5k also showed significant protective effect against A. solani infection on tomatoes in a concentration-dependent manner. Action mechanism research showed that 5k was able to increase the intracellular ROS level, change both MMP and permeability of cell membrane and damage mycelial morphology. Molecular docking studies showed that 5k could bind into ubiquinone-binding region of succinate dehydrogenase by hydrogen bonds, π-cation, π–π stacked, π-alkyl, and alkyl interactions. Additionally, the antibacterial activity was also investigated. Thus, N -substituted derivatives of N ′-phenylpicolinohydrazide were emerged as novel and highly promising antifungal molecular skeletons to develop new fungicides for crop protection. Graphic abstract

Impact of Adding N-hexylamine to Nickel Metallophotoredox C–N Coupling to Form Diarylamines

Haiyang Wang,Fujun Li,Wenbo Yang,Yuchao Wang,Alexander A. Miskevich,Valery A. Loiko,Lijing Zhang,Shengyang Tao

The mechanistic understanding of how alkylamines impact Ni-metallophotoredox C–N coupling to form diarylamines remains unclear. In this study, 12-alkylamines were evaluated as additives to determine their effects on the synthesis of diarylamines in a flow photochemical system. Notably, n-hexylamine demonstrated the most significant promotional effect. Spectroscopic studies and experimental data reveal n-hexylamine substitutes DABCO as a Ni catalyst ligand, enhancing yields particularly in sterically hindered arylamines.

N−N Heterostructure Sm2O3/ZnO Electrolyte with Enhanced Proton Conduction for Fuel Cell Application

Xiuxiu Li,Enyi Hu,Faze Wang,Peter D. Lund,Jun Wang

Samarium oxide (Sm2O3) is a promising electrolyte for low-temperature fuel cells but lacks further exploration of performance optimization. Herein, we propose an effective approach to strengthen the proton transport characteristics via constructing a heterostructure interface in a Sm2O3/ZnO composite electrolyte. The constructed optimal 6Sm2O3-4ZnO cell device yields an improved peak power density of 920 mW cm–2 and an extended durability performance of 45 h at 500 °C. Experiments confirm the proton conduction, and the density functional theory calculation further discloses the low proton migration energy of 0.35 eV. The semiconductor junction test and theoretical calculation both reveal that the heterojunction exists at the Sm2O3/ZnO interface. The strong local electric field strength of 1.53 × 107 V m–1 at the interface effectively suppresses short circuit and accelerates proton transport, leading to significantly enhanced electrochemical performance. This study indicates that the 6Sm2O3-4ZnO material is a promising electrolyte candidate for fuel cell application.

Performance comparison of chiral separation materials derived from N-cyclohexylcarbonyl and N-hexanoyl chitosans

Sheng Tang,Jian-De Liu,Wei Chen,Shao-Hua Huang,Juan Zhang,Zheng-Wu Bai

Chitosan bis(phenylcarbamate)-( N -cyclohexylformamide)s and chitosan bis(phenylcarbamate)-( N -hexanamide)s were synthesized as chiral selectors for enantiomeric separation. Since two types of substituents with different structures were, respectively, introduced onto the 2-position and the 3-/6-positions of the glucose skeleton in the chitosans through a “heterogeneous” modification pathway, the enantioseparation performances of the chiral selectors could be improved. Influence of the type and position of the substituents on chiral recognition and enantioseparation abilities was studied in detail, and the structural dependence on enantioseparation performance was particularly demonstrated. It was found that methyl- and chloro-substituted chitosan bis(phenylcarbamate)-( N -hexanamide)s possessed comparable enantioseparation performances, whereas chloro-substituted chitosan bis(phenylcarbamate)-( N -cyclohexylformamide)s exhibited much more powerful chiral recognition and enantioseparation abilities than the methyl-substituted ones. Among all the prepared chiral selectors, those with the combination of the cyclohexyl group at the 2-position of the glucose skeleton in the chitosan derivatives and the chlorophenyl group at the 3-/6-positions seemed to be more preferable for enantiomeric separation. As a result, the chitosan bis(3,4-dichlorophenylcarbamate)-( N -cyclohexylformamide) possessed the best enantioseparation performance. The solvent tolerability of the prepared chiral selectors was also investigated in the present study. Compared with the classical coated-type chiral separation materials derived from cellulose/amylose derivatives, the N -cyclohexylcarbonyl and N -hexanoyl chitosans based chiral stationary phases were observed to possess more favorable solvent tolerability, thus possibly widening their applications for various practical enantioseparations.

Uptake, translocation and biotransformation of N-ethyl perfluorooctanesulfonamide (N-EtFOSA) by hydroponically grown plants

Shuyan Zhao,Tao Zhou,Lingyan Zhu,Bohui Wang,Ze Li,Liping Yang,Lifen Liu

N-ethyl perfluorooctane sulfonamide (N-EtFOSA) is an important perfluorooctanesulfonate (PFOS) precursor (PreFOS) which is used in sulfluramid. The present work studied the uptake, translocation and metabolism of N-EtFOSA in wheat ( Triticum aestivum L.), soybean ( Glycine max L. Merrill) and pumpkin ( Cucurbita maxima L.) by hydroponic exposure. Except for parent N-EtFOSA, its metabolites of perfluorooctane sulfonamide acetate (FOSAA), perfluorooctane sulfonamide (PFOSA), PFOS, perfluorohexane sulfonate (PFHxS) and perfluorobutane sulfonate (PFBS) were detected in the roots and shoots of all the three plant species examined. This suggested that plant roots could take up N-EtFOSA from solutions efficiently, and translocate to shoots. A positive correlation was found between root concentration factors (RCFs) of N-EtFOSA and root lipid content. Much higher proportion of N-EtFOSA transformation products in plant tissues than in the solutions suggested that N-EtFOSA could be in vivo metabolized in plant roots and shoots to FOSAA, PFOSA and PFOS, and other additional shorter-chain perfluoroalkane sulfonates (PFSAs), including PFHxS and PFBS. The results suggested that plants had biotransformation pathways to N-EtFOSA that were different than those from microorganisms and animals. This study provides important information about the uptake and metabolism of PreFOSs in plants.

A Tough and Piezoelectric Poly (acrylamide/ N, N-dimethylacrylamide) Hydrogel-based Flexible Wearable Sensors

Mingyue Wu,Guohui Wang,Mihan Zhang,Jinchao Li,Chenglong Wang,Guangdong Sun,Jinhuan Zheng

A flexible, tough, highly transparent and piezoelectric polyacrylamide hydrogel was fabricated induced by blue light photocuring, with camphorquinone/diphenyliodonium hexafluorophosphate (CQ/DPI) as the blue light initiator, acrylamide (AM) and N, N-dimethylacrylamide (DMAA) as monomers, polyethylene glycol diacrylate (PEGDA) as the crosslinker, lecithin as the dispersant, and BaTiO3 as the piezoelectric material. Various performance tests were carried out on the hydrogel, the results showed that lecithin enhances the dispersion of BaTiO3 within the system and improved the tensile properties (>100% strain) of the hydrogel, and the addition of PEGDA not only improves the photopolymerization performance of hydrogel, but also significantly improves its fracture strength (~ 0.3 MPa). In addition, BaTiO3 enables the result hydrogels show excellent conductivity (> 1.5) and stable response to strain. The assembled hydrogel sensor shows a sensitive response to human joint activities, which is expected to be applied in self-powered sensors and energy collection.

Salt-induced wormlike micelles formed by N-alkyl-N-methylpyrrolidinium bromide in aqueous solution

Jun Li,Mingwei Zhao,Liqiang Zheng

The wormlike micelles formed by surface active N -alkyl- N -methylpyrrolidinium bromide ionic liquids (ILs) have been investigated in aqueous solution. The typical rheological parameters and the viscoelastic properties of wormlike micelles were characterized by rheological measurements and cryogenic-transmission electron microscopy (cryo-TEM). The typical rheological parameters were further evaluated by Maxwell model and the viscoelastic properties were discussed based on the living polymer model. Cryo-TEM images confirmed the formation of wormlike micelles in aqueous solution. The effect of the hydrocarbon chain length of the ILs on the wormlike micelles formation was also studied.

Thermal conductivity measurements for n-hexane and n-heptane at elevated temperature and pressure

Yuxuan Chen,Wanlin Xu,Mengyi Wang,Xiong Zheng

Thermal conductivity is a very important thermal property parameter in the process of hydrocarbons transportation, storage, combustion and cooling. Therefore, accurate thermal conductivity is important in the utilization of hydrocarbons. In this work, the thermal conductivity of n-hexane and n-heptane in the temperature range of 298.15 K∼523.15 K and pressure range of 0.1 MPa∼15.0 MPa was studied by using transient hot-wire method. In order to facilitate engineering application, function polynomials of temperature and pressure are fitted and correlated with experimental data. The average absolute error of the experimental data and fitting data of n-hexane and n-heptane are 0.72 and 0.61 %, respectively, which proves that the function polynomial can describe the experimental data well. In addition, we compare the collected literature data with our results and find that the literature data is very close to our results. This work is expected to expand the range of available data on the thermal conductivity of n-hexane and n-heptane and contribute to the industrial applications of these two substances.