JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2019
·
IF 6.361
Xian Sun,Qi Qiang,Zhiguang Yin,Zenglin Wang,Yi Ma,Chuan Zhao
Alloyed nanoparticles are promising electrocatalysts for electrochemical energy storage and conversion devices. However, syntheses of alloyed nanoparticles with controllable size and stoichiometry remain challenging. In this study, continuous, uniform and monodispersed bimetallic AgPd nanoparticles (NPs) with diameters ∼10 nm are achieved by electrochemical synthesis from quaternary ionic liquid microemulsion (ILM) for use as electrocatalysts for ethanol oxidation reaction (EOR). It is found that the ionic liquid, 1-butyl-3-methyl-imidazolium chloride ([BMIM]Cl), acts not only as a soft template and co-surfactant for the formation of micro-reactors, but also as an electrolyte for enhancing conductivity. The stoichiometry (Ag x Pd y ), size and size distribution of AgPd NPs can be accurately tuned by varying electrolyte composition , electrodeposition conditions, and ionic liquids concentrations. Attributed to the high surface area, optimal stoichiometric ratio, and strong attachment onto substrates without using organic binders, the as-deposited Ag x Pd y NPs exhibit extraordinary electrocatalytic activity and stability for EOR. It is found that the mass activity of Ag 49 Pd 51 NPs/Pt electrode reaches 3360 mA mg −1 for EOR in 1.0 M ethanol and 1.0 M KOH aqueous solution, which is much higher than commercial Pd/C catalyst (210.5 mA mg −1 ) and also the highest among state-of-the-art AgPd NPs electrocatalysts reported to date for EOR in alkaline media.
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JOURNAL OF MEMBRANE SCIENCE
·
2018
·
IF 6.578
Qian Yang,Chen Xiao Lin,Fang Hua Liu,Ling Li,Qiu Gen Zhang,Ai Mei Zhu,Qing Lin Liu
To improve the overall performance of anion exchange membranes (AEMs) for fuel cells, a series of composite AEMs was prepared via a facile approach using ionic liquid-functionalized graphene oxide (IL-GO) and imidazolium-functionalized poly (2,6-dimethyl-1,4-phenylene oxide) (ImPPO). The prepared ImPPO/IL-GO-0.5% (0.5% refers to the weight percentage of IL-GO) membranes with an ionic exchange capacity (IEC) of 1.9 meq g −1 achieved a hydroxide conductivity of 78.5 mS cm −1 . The high conductivity of ImPPO/IL-GO-0.5% is due to the fact that the ionic cluster size of composite membranes (3.43–3.58 nm) is larger than that of the pristine membrane (3.30 nm). The ionic cluster morphology is confirmed by atomic force microscopy (AFM) and small angle X-ray scattering (SAXS). Moreover, the AEMs retained approximately 70% of their initial hydroxide conductivity after the alkaline stability test in a 2 M aqueous NaOH at 80 °C for 480 h, indicating a good alkaline stability. A single cell using ImPPO/IL-GO-0.5% exhibits a peak power density of 136 mW cm −2 at 60 °C under 100% related humidity, thereby having a great potential for fuel cells.
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RSC Advances
·
2018
·Vol. 8
·期 13
·7179-7185
·
IF 2.936
Ruiyun Li,Heyuan Song,Guoqin Wang,Jing Chen
Ketalization of cyclohexanone with glycol has been carried out using molecular sieve SBA-15 immobilized Brønsted acidic ionic liquid catalyst. The properties of the heterogeneous catalysts were characterized by elemental analysis, Fourier transform infrared (FT-IR) spectra, scanning electron microscopy (SEM), thermogravimetry/differential scanning calorimetry (TG/DSC), and N2 adsorption–desorption (BET). The results suggested that Brønsted acidic ionic liquid [BSmim][HSO4] had been successfully immobilized on the surface of SBA-15 and the catalytic performance evaluation demonstrated that the catalyst BAIL@SBA-15 exhibited excellent catalytic activities in the ketalization of cyclohexanone with glycol. In addition, the effects of reaction temperature, catalyst loading, reaction time, and reactant molar ratio have also been investigated in detail, and a general reaction mechanism for the ketalization of cyclohexanone with glycol was given. The SBA-15 immobilized ionic liquid can be recovered easily and after reusing for 5 times in the ketalization reaction, the catalyst could still give satisfactory catalytic activity.
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GREEN CHEMISTRY
·
2018
·Vol. 20
·期 4
·903-911
·
IF 8.586
Jian Chen,Mingmei Zhong,Lin Tao,Lina Liu,Sanjeevi Jayakumar,Chunzhi Li,He Li,Qihua Yang
The cooperation of catalyst and co-catalyst, together with efficient recycling, is one of the most important and still big challenges for CO2 cycloaddition reaction. Herein, we report a facile and atom-efficient method to synthesize a porous zinc-porphyrin-based framework (P-POF-Zn) as a catalyst for the synthesis of cyclic carbonates. It was demonstrated for the first time that the combination of P-POF-Zn and thermal-responsive ionic liquid [CPeDMAPy]Br (soluble in PO and PC at high temperature but not at room temperature) could efficiently catalyze the cycloaddition reaction of CO2 and propylene oxide to afford a turnover frequency of 433 h−1. The high catalytic activity is mainly attributed to the efficient cooperation of P-POF-Zn (Lewis acid site) and [CPeDMAPy]Br (nucleophile). Both P-POF-Zn and [CPeDMAPy]Br could be fully recovered after reaction by simple filtration for stable recycling. This work demonstrates the efficiency of the combination of thermal-responsive reagents with solid catalyst for catalyzing chemical reactions via a cooperation activation pathway.
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ACS Applied Materials & Interfaces
·
2018
·
IF 8.097
Haozhen Dou,Bin Jiang,Xiaoming Xiao,Mi Xu,Xiaowei Tantai,Baoyu Wang,Yongli Sun,Luhong Zhang
Protic ionic liquids (PILs) were utilized for the fabrication of composite membranes containing silver salt as the C2H4 transport carrier to perform C2H4/C2H6 separation for the first time. The intrinsic nanostructures of PILs were adopted to construct fast and selective C2H4 transport nanochannels. The investigation of structure–performance relationships of composite membranes suggested that transport nanochannels (polar domains of PILs) could be tuned by the sizes of cations, which greatly manipulated activity of the carrier and determined the separation performances of membranes. The role of different carriers in the facilitated transport was studied, which revealed that the PILs were good solvents for dissolution and activation of the carrier due to their hydrogen bond networks and waterlike properties. The operating conditions of separation process were investigated systemically and optimized, confirming C2H4/C2H6 selectivity was enhanced with the increase of silver salt concentration, the flow rate of sweep gas, and the feed ratio of C2H4 to C2H6, as well as the decrease of the transmembrane pressure and operating temperature. Furthermore, the composite membranes exhibited long-term stability and obtained very competitive separation performances compared with other results. In summary, PIL composite membranes, which possess good long-term stability, high C2H4/C2H6 selectivity, and excellent C2H4 permeability, may have a good perspective in industrial C2H4/C2H6 separation.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2018
·
IF 3.909
Hongbo Suo,Lili Xu,Chao Xu,Hongyue Chen,Dinghua Yu,Zhen Gao,He Huang,Yi Hu
Magnetic chitosan nanocomposites were designed and fabricated by combining the magnetic nanoparticles Fe 3 O 4 and chitosan covalently modified by imidazole-based ionic liquids with various functional groups, to be utilized as a support matrix for immobilization of porcine pancreatic lipase (PPL). Ionic liquids modified chitosan was characterized with nuclear magnetic resonance (NMR) and the nanocomposites were characterized with Fourier transform infrared spectroscopy (FTIR), vibrating-sample magnetometer (VSM), thermogravimetry analysis (TGA), Transmission electron microscope (TEM) and Scanning electron microscopy (SEM). The enzymatic properties of PPL were significantly improved by immobilization onto all thus prepared nanocomposites, and among the supports, modified with ionic liquids bearing hydroxyl group exhibited relatively enhanced performance. Particularly, the MCS-IL(8C)-OH-PPL exhibited the highest specific activity which was 6.68 times that of free PPL, and the residual activity of MCS-IL(8C)-OH-PPL remarkably maintained 91.5% of its initial activity even after 10 repeated cycles. The residual activity of MCS-IL(8C)-OH-PPL retained 55.8% after incubated in 6 M urea solution for 1 h and maintained the noticeable initial activity of 75.5% after incubated in phosphate buffer at 50 °C with pH 7.5 for 6 h. In conclusion, the study demonstrated that Fe 3 O 4 @Chitosan nanocomposites modified with functional ionic liquids could be utilized as a novel nanosupport for enzyme immobilization .
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ELECTROPHORESIS
·
2018
·Vol. 39
·期 14
·1771-1776
·
IF 2.569
Mei-E Yue,Qiaoyan Lin,Jie Xu,Ting-Fu Jiang
An ionic liquid-based headspace in-tube liquid-phase microextraction (IL-HS-ITLPME) in-line coupled with CE is proposed. The method is capable of quantifying trace amounts of phenols in environmental water samples. In the newly developed method, simply by placing a capillary injected with ionic liquids (IL) in the HS above the aqueous sample, volatile phenols were extracted into the IL acceptor phase in the capillary. After extraction, electrophoresis of the phenols in the capillary was carried out. Extraction parameters such as the extraction time, extraction temperature, ionic strength, volume of the sample solution, and IL types were systematically investigated. Under the optimized conditions, enrichment factors for four phenols were from 1510 to 1985. The proposed method provided a good linearity, low limits of detection (below 5.0 ng/mL), and good repeatability of the extractions (RSDs below 6.7%, n = 6). This method was then utilized to analyze two real environmental samples of Xiaoxi Lake and tap water, obtaining acceptable recoveries and precisions. Compared with the usual HS-ITLPME for CE, IL-HS-ITLPME-CE is a simple, low cost, fast, and environmentally friendly preconcentration technique.
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CATALYSIS TODAY
·
2018
·
IF 4.667
Xian-Dong Lang,Zheng-Ming Li,Liang-Nian He
The thermodynamic stability and kinetic inertness represent substantial obstacles for direct chemical transformation of CO 2 . Consequently, conversion of the CO 2 equivalent in an efficient and energy-saving manner has gained much attention being viewed as an indirect pathway to chemical utilization of CO 2 . In this article, we would like to report the synthesis of oxazolidinones via the carboxylative cyclization of anilines with cyclic carbonate using protic ionic liquid 1,8-diazabicyclo[5.4.0]-7-undecenium imidazolide [HDBU][Im] as the bifunctional catalyst under mild conditions without addition of conventional organic solvents. The distinguished features of this protocol include low catalyst loading, wide functionality tolerance and convenient recycling of the catalyst. A series of functional groups such as Cl, Br, CH 3 , OCH 3 and NO 2 can be well tolerated under the reaction conditions, providing the corresponding products in moderate to good yields (61–92%). In addition, to shed light on the cooperative interactions of [HDBU][Im]/EC and [HDBU][Im]/aniline, NMR technique and DFT study were also performed, respectively.
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JOURNAL OF MOLECULAR LIQUIDS
·
2018
·
IF 4.513
Bing Liu,Su Wang,Yongzhong Jia,Wenbo Zhu,Quanyou Zhang,Xingquan Wang,Ying Yao,Yan Jing
A green and efficient ionic liquid-anisole extraction system was employed for the separation of lithium isotopes by comparing 4‑aminobenzo‑15‑crown‑5 (4‑NH 2 ‑B15C5), 4‑nitrobenzo‑15‑crown‑5 (4‑NO 2 ‑B15C5) and benzo‑15‑crown‑5 (B15C5) extraction agents. The results of the effects of crown ether substituents, crown ether concentration and lithium salt anion on solvent extraction indicated that the molar ratio of crown ether and lithium ion complex is 2:1 and the order of the extraction efficiency in three extraction agents was 4‑NH 2 ‑B15C5 > B15C5 > 4‑NO 2 ‑B15C5. Furthermore, the single-stage separation factor α for 6 Li/ 7 Li obtained in present work was 1.032 and maximum abundance of 6 Li in organic phase was reached 7.762% in the extraction system of LiI/4‑NO 2 ‑B15C5‑ILs.
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ELECTROCHIMICA ACTA
·
2018
·
IF 5.116
Xu Wang,Shuang Wang,Chang Liu,Jinsheng Li,Fengxiang Liu,Xue Tian,Hao Chen,Tiejun Mao,Jingmei Xu,Zhe Wang
Polybenzimidazole/ionic liquid (IL) composite membranes with cage-like cross-linked structure were prepared based on polybenzimidazole containing hydroxyl groups (PBIOH30), 3-(triethoxysilyl) propyl isocyanate (IPTS) and 1-butyl-3-methylimidazolium dihydrogen phosphate (BMI-DHPH). The basic characteristic of imidazole rings in IL enhanced the phosphoric acid (PA) doping ability of the obtained cPBI-IL X membranes, thus, the proton conductivity of which was elevated. The cage-like cross-linked structure was formed under acidic conditions, and such structure can not only strengthen the mechanical properties of cPBI-IL X membranes but also prevent the leakage of the IL to some extent. The IL retention ability of cPBI-IL 10 was significantly improved, the residual weight percentage of IL was 71.6 wt%, while that of PBI-IL 10 membrane without cage-like cross-linked structure was only 2 wt%. The membrane with 8 wt% IL content exhibited the highest proton conductivity of 0.133 S cm −1 at 160 °C.
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JOURNAL OF MATERIALS SCIENCE
·
2017
·Vol. 53
·期 7
·4927-4938
·
IF 2.599
Liu Ran,Zhang Juan,Xu Zhice,Zhao Dishun,Sun Shuang
Iron phthalocyanine (PcFe) was loaded on Ti-MCM-41 as visible light photocatalyst (R-PcFe/Ti-MCM-41). Dibenzothiophene (DBT) was photooxidized using R-PcFe/Ti-MCM-41 as a photocatalyst, air as an oxidant, and ionic liquid as the extraction agent during visible light irradiation at room temperature and ambient conditions. The results indicated that photocatalytic efficiency of the amino iron phthalocyanine (NH 2 -PcFe)/Ti-MCM-41 was superior to the other substituent groups. The DBT content in the model oil decreased from 1000 to 44 μg/mL with 95.6% removal rate under the optimal reaction conditions (model oil 10 mL, photocatalyst NH 2 -PcFe/Ti-MCM-41 0.02 g, loading amount of NH 2 -PcFe 0.3 g/g, air flow rate 100 mL/min, reaction time 2 h, room temperature). The kinetics of photocatalytic oxidation of DBT follows first-order kinetics with a rate constant of 1.319 h −1 and halftime of 0.525 h. The photocatalyst NH 2 -PcFe/Ti-MCM-41 was reused for five times, and the catalytic activity decreased slightly. The photocatalytic oxidation system demonstrated significant desulfurization effects on different sulfur compounds and real gasoline, and the sulfur content of the actual gasoline could be reduced from 1000 to 78 ppm.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2017
·Vol. 410
·期 2
·595-604
·
IF 3.431
Jia Man,Yang Jian,Sun Ya Kun,Bai Xi,Wu Tao,Liu Zhao Sheng,Aisa Haji Akber
We aimed to improve the imprinting effect of ionic liquid molecularly imprinted polymers (MIPs) by use of a molecular crowding agent. The ionic liquid 1-vinyl-3-ethylimidazolium tetrafluoroborate ([VEIm][BF 4 ]) was used as the functional monomer and aesculetin was used as the template molecule in a crowding environment, which was made up of a tetrahydrofuran solution of polystyrene. The ionic liquid MIPs that were prepared in the crowding environment displayed an enhanced imprinting effect. NMR peak shifts of active hydrogen of aesculetin suggested that interaction between the functional monomer and the template could be increased by the use of a crowding agent in the self-assembly process. The retention and selectivity of aesculetin were affected greatly by high molecular crowding, the amount of high molecular weight crowding agent, and the ratio of [VEIm][BF 4 ] to aesculetin. The optimal MIPs were used as solid-phase extraction sorbents to extract aesculetin from Cichorium glandulosum . A calibration curve was obtained with aesculetin concentrations from 0.0005 to 0.05 mg mL −1 (correlation coefficient R
2 of 0.9999, y = 1519 x + 0.0923). The limit of quantification was 0.12 μg mL −1 , and the limit of detection was 0.05 μg mL −1 . The absolute recovery of aesculetin was (80 ± 2)% ( n = 3), and the purity of aesculetin was (92 ± 0.5)% ( n = 5). As a conclusion, molecular crowding is an effective approach to obtain ionic liquid MIPs with high selectivity even in a polar solvent environment.
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