Institute of Chemistry
Changchun Institute of Applied Chemistry, Chinese Academy Of SciencesNot a member yet
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Growth Control of MoS2 Nanosheets on Carbon Cloth for Maximum Active Edges Exposed: An Excellent Hydrogen Evolution 3D Cathode
No full textTo greatly improve the hydrogen evolution reaction (HER) performance, it is the key approach to expose as many active edges of MoS2 as Possible. This target is the research hotspot and difficulty of MoS2 which is a promising HER catalyst. In this work, we realized the active-edges control of MoS2 nanosheets on carbon cloth (CC) by growth control during the synthesis procedure. Moreover, MoS2 nanosheets vertically grown on carbon cloth (MoS2 perpendicular to CC) was confirmed to be the best morphology with maximum active edges exposed. Multifactors structure control resulted in abundant active-edges exposure and effective electron delivery, thus excellent HER activity. This three-dimensional cathode, MoS2 perpendicular to CC, can reach a great current density of 200 mA/cm(2) at a small overpotential of 205 mV. The preeminent HER performance can rival the best MoS2-based catalyst ever reported
Warm White Light Emitting Diodes with Gelatin-Coated AgInS2/ZnS Core/Shell Quantum Dots
No full textCadmium-free and water-soluble AgInS2/ZnS core/shell quantum dots (QDs) with a cost of 2.5 $/g are synthesized in an electric pressure cooker. The QD powders with different Ag/In ratios exhibit bright yellow, orange, and orange-red luminescence under UV light. Their absolute photoluminescence quantum yields (PLQYs) can reach as high as 50.5, 57, and 52%, respectively. Because gelatin is used as the capping agent, the concentrated QDs/gelatin solution can be directly utilized as phosphor for the fabrication of white light-emitting diodes (LEDs) by a simple drop-drying process without the need of resin package. Warm-white LEDs are obtained by combining orange-emitting QDs with blue InGaN chip. As-fabricated warm-white LED exhibits a luminous efficacy of 39.85 lm/W, a correlated color temperature (CCT) of 2634 K and a color rendering index (Cm) of 71 at a drive current of 20 mA. Furthermore, the electroluminescence (EL) stability of LED device and thermal stability of as-prepared QDs are evaluated
Highly sensitive and selective colorimetric detection of glutathione based on Ag [I] ion-3,3 ',5,5 '-tetramethylbenzidine (TMB)
No full textGlutathione (GSH) plays an important role in the biological system and serves many cellular functions. Since all of the biothiols possess similar functional groups, it is still challenging to selectively detect GSH over cysteine (Cys) and homocysteine (Hcy). In this work, a novel and simple colorimetric method for discriminative detection of glutathione (GSH) over Cys and Hcy is developed. The proposed method is based on the fact that Ag [I] ion could oxidize 3,3',5,5',-tetramethylbenzidine (TMB) to the oxidized TMB to induce a blue color and an absorption peak centered at 652 nm. However, the introduction of GSH could cause the reduction of oxidized TMB and it could also combine with Ag+, both of which result in a blue color fading and a decrease of the absorbance at 652 nm. Based on this finding, we propose a method to qualitatively and quantitatively detect GSH by naked eyes and UV-vis spectroscopy, respectively. The proposed method shows a low detection limit of 0.1 mu M by naked eyes and 0.05 mu M with the help of UV-vis spectroscopy. In addition, this method has great potential in discriminatively detecting GSH over other amino acid and biothiols. More importantly, this method is simple and fast without the preparation of nanomaterials and has also been successfully applied to the detection of GSH in biological fluids. (C) 2014 Elsevier B.V. All rights reserved
Highly sensitive and specific colorimetric detection of cancer cells via dual-aptamer target binding strategy
No full textSimple, rapid, sensitive and specific detection of cancer cells is of great importance for early and accurate cancer diagnostics and therapy. By coupling nanotechnology and dual-aptamer target binding strategies, we developed a colorimetric assay for visually detecting cancer cells with high sensitivity and specificity. The nanotechnology including high catalytic activity of PtAuNP and magnetic separation & concentration plays a vital role on the signal amplification and improvement of detection sensitivity. The color change caused by small amount of target cancer cells (10 cells/mL) can be clearly distinguished by naked eyes. The dual-aptamer target binding strategy guarantees the detection specificity that large amount of non-cancer cells and different cancer cells (10(4) cells/mL) cannot cause obvious color change. A detection limit as low as 10 cells/mL with detection linear range from 10 to 10(5) cells/mL was reached according to the experimental detections in phosphate buffer solution as well as serum sample. The developed enzymefree and cost effective calorimetric assay is simple and no need of instrument while still provides excellent sensitivity, specificity and repeatability, having potential application on point-of-care cancer diagnosis. (C) 2015 Elsevier B.V. All rights reserved
Base-Promoted Consecutive Enolate Addition Reaction of [60]Fullerene with Ketones
No full text[60]Fullerene derivatives with novel 1,4,9,25- and 1,4,9,12-configurations were obtained by reactions of C-60 with aliphatic ketones and benzyl bromide under basic conditions. The structures of the products were determined by X-ray single-crystal diffraction and spectroscopic characterization. The reactions were rationalized by a monoenolate addition experiment and in situ vis-NIR spectroscopy
Solvation effect on intercalation behaviour of tetrafluoroborate into graphite electrode
No full textAnion-intercalated graphite compounds are becoming attractive as high-potential positive electrode materials in some electric energy storage devices. The intercalation of anions from electrolyte solutions to graphite electrode generally involves the co-entrance of organic solvent molecules inside the interlayer galleries of graphite, which has a great impact on the electrochemical behaviour of the graphite electrode. In situ XRD (X-ray diffraction) and EQCM (Electrochemical quartz crystal microbalance) techniques have been corporately employed to investigate the mechanism of BF4- intercalation into graphite positive electrode from three electrolyte solutions in activated carbon/graphite capacitors. The solvation states of BF4- by different solvents inside the graphite electrode have been correlated with the performance of AC/graphite capacitors using corresponding electrolyte solutions. (C) 2014 Elsevier B.V. All rights reserved
Titanium dioxide encapsulated in nitrogen-doped carbon enhances the activity and durability of platinum catalyst for Methanol electro-oxidation reaction
No full textThe development of advanced catalyst supports is a promising route to obtain active and durable electrocatalysts for methanol electro-oxidation reaction. In the current work, nitrogen-doped carbon encapsulated titanium dioxide composite (TiO2@NCx) is constructed and serves as support material for the Pt catalyst. The TiO2@NCx support is fabricated by the procedure of an in-situ polymerization and subsequent pyrolysis. The synthesized Pt/TiO2@NCx catalysts show enhanced electrocatalytic performance towards methanol electro-oxidation compared with the commercial Pt/C catalyst. The enhancement can be ascribed to combinatory effect of N-doped carbon and TiO2, in which the tolerance to CO-poisoning and the intrinsic kinetics of methanol oxidation reaction are simultaneously improved by the bifunctional mechanism and the electronic effect. As a result, the as-developed TiO2@NCx composite is a promising catalyst support material for the application in fuel cell. (C) 2015 Elsevier B.V. All rights reserved
Structure-activity relationship in high-performance iron-based electrocatalysts for oxygen reduction reaction
No full textA sustainable Iron (Fe), Nitrogen (N) co-doped high performance Fe-N-x/C electrocatalyst for oxygen reduction reaction (ORR) is synthesized simply based on nitric acid oxidation of cheap carbon black. The obtained optimal nonprecious metal electrocatalyst shows high ORR performance in both alkaline and acidic conditions and possesses appreciable performance/price ratio due to its low cost. Furthermore, the structure-activity relationship of different active sites on Fe-N-x/C is revealed systematically: Fe-N-4/2-C > Fe-4-N-C > N-C >> Fe-4-C <= C, from both experimental and theoretical points of view. (C) 2015 Elsevier B.V. All rights reserved
Charge-conversional zwitterionic copolymer as pH-sensitive shielding system for effective tumor treatment
No full textA novel pH-responsive gene delivery system for tumor acidity-targeted pDNA delivery is prepared by introducing a rapid charge-conversional zwitterionic copolymer to the positive surface of PEI/pDNA complexes through electrostatic interaction. The shielding system (OEAL) consists of oligoethylenimine (OEI), poly(L-aspartate) (PBLA), and poly(L-lysine) (PLL). The charge-conversional behavior of the OEAL/PEI/DNA ternary complex is evaluated by zeta potential assay. The surface charges of the complexes can change from negative to positive in the pH range of 7.4-6.8. Under a simulative in vivo environment, OEAL/PEI/DNA exhibits promotion of cellular uptake by tumor cells and enhanced gene transfection efficiency because of its good charge-conversional properties. Antitumor experiments further show that the pH-responsive charge-conversional system can mediate a therapeutic gene that can induce tumor apoptosis (pKH3-rev-casp-3) to achieve effective tumor inhibition. Accordingly, OEAL can be regarded as a promising tumor microenvironment-sensitive gene delivery shielding system for antitumor therapy
Highly Syndioselective 3,4-Trans Polymerization of (E)-1-(4-Methylpheny1)-1,3-butadiene by Fluorenyl N-Heterocyclic Carbene Ligated Lutetium Bis(alkyl) Precursor
No full text(E)-1-(4-Methylphenyl)-1,3-butadiene (E-1-MPBD) synthesized via the Wittig-type reaction was polymerized with the ternary catalytic system (Flu-NHC)Lu(CH2SiMe3)(2)/AliBu(3)/[Ph3C][B(C6F5)(4)] (Flu-NHC = C13H8CH2CH2(NCHCHN(C6H2Me3-2,4,6)C) to afford a new product containing exclusively trans-3,4 (>99%) units with perfect syndiotacticity (rrrr > 99%). The regio-3,4 tacticity was proved by the IR and NMR (H-1 and C-13) spectroscopic analyses, while the 3,4-stereotacticity was confirmed by a model polymer with lower regularity (3,4 = 90.9%, rrrr = 49.3%) prepared by the binary catalytic system (Am-NHC)Lu(CH2SiMe3)(2)/[Ph3C][B(C6F5)(4)] (Am-NHC = 2,6-(PrC6H3N)-Pr-i-C(C6H5)NCH2CH2(NCHCHN(C6H2Me3-2,4,6)C). The trans-planar conformation was uncovered through 2D-NOESY and C-13 CPMAS NMR technologies. This represents the first stereo 3,4-syndioselective polymerization of 1,3-dienes achieved by a rare-earth metal based catalyst. Moreover, hydrogenating the resulting polymer gave the highly syndiotactic poly(4-methylphenyl-1-butene), which cannot be achieved by any other manner at the present stage