Co-reporter:Manhua Peng, Dongtang Zhang, Limin Zheng, Xiayan Wang, Yue Lin, Dingguo Xia, Yugang Sun, Guangsheng Guo
Nano Energy 2017 Volume 31() pp:64-73
Publication Date(Web):January 2017
DOI:10.1016/j.nanoen.2016.11.023
•Na3V2O2(PO4)2F (I4/mmm) sodium cathode materials with unique three-dimensional (3D) hierarchical structure overcoming the limitations of nanoparticles was successfully synthesized via a low-temperature solvothermal method.•The synthesized hollow microspheres materials of Na3V2O2(PO4)2F, Ru-doped Na3V2O2(PO4)2F, and Ru-doped Na3V2O2(PO4)2F with RuO2 coating used in SIBs exhibited high reversible capacity, long cycle stability, and excellent rate performance.•The formation mechanism of ordered hierarchical hollow microspheres controlled by the adsorption of hydrogen was systematically investigated via a series of experimentsand density functional theory (DFT) calculations providing insight to the design and synthesis of new electrode materials with the potential for future applications.Novel hierarchical Ru-doped Na3V2O2(PO4)2F hollow microspheres were synthesized via a low-temperature solvothermal method. The individual unique microspheres were formed from assembly of numerous nanoparticles with diameters of 20–30 nm. When used as a cathode material for sodium-ion batteries (SIBs), the microspheres exhibited superior rate performance with a capacity of 72.6 mAh·g−1 at 10 C. Furthermore, their rate performance could be significantly improved by coating them with a thin conductive RuO2 layer. For instance, high specific capacities of 102.5 mAh g−1 and 44.9 mAh g−1 were achieved at current rates of 20 C and 100 C, respectively. These materials exhibited impressive long-term cycling stability. A reversible capacity of approximately 55.0 mAh g−1 was maintained even after 7500 charge/discharge cycles. Density functional theory (DFT) calculations increased our understanding of how H+ facilitates the formation of the hierarchical microsphere superstructure which is beneficial to achieve a good rate capability.Novel hierarchical Ru-doped Na3V2O2(PO4)2F hollow microspheres with RuO2 coated were successfully synthesized, and exhibited an excellent long-term cycling stability as a cathode material for sodium-ion batteries.
Co-reporter:Zunsheng Han;Liping Lu;Lin Wang;Zimeng Yan
Chromatographia 2017 Volume 80( Issue 9) pp:1353-1360
Publication Date(Web):25 July 2017
DOI:10.1007/s10337-017-3358-3
A reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed and validated for determination of ibuprofen and 17 related compounds (chemical process impurities and degradation products) simultaneously. This method may be used for quality control of ibuprofen-containing substances. A number of chromatographic parameters (column, flow rate, temperature, wavelength, gradient elution, buffer solution, and pH) were evaluated. An Agilent ZORBAX Eclipse Plus C18 (250 × 4.6 mm, 5 μm particle size) column at 40 °C was selected on the basis of its separation efficiency and robustness. The column was eluted at 1.0 mL min−1 with a gradient using 10 mM sodium phosphate buffer at pH 6.9 as mobile phase A and acetonitrile as mobile phase B. The ultraviolet detector was set at 214 nm. This method was validated to confirm its system suitability, specificity, linearity, precision, accuracy, sensitivity, robustness, and sample stability according to international conference on harmonization (ICH) guidelines. This method was applied to analyze seven batches of ibuprofen drug products from different manufacturers.
Co-reporter:Shenghong Yang, Xiaohan Sun, Zhaoyan Wang, Xiayan Wang, Guangsheng Guo, Qiaosheng Pu
Sensors and Actuators B: Chemical 2017 Volume 253(Volume 253) pp:
Publication Date(Web):1 December 2017
DOI:10.1016/j.snb.2017.06.137
•A highly fluorescent molecule TPCA was synthesized by a one-step green route.•TPCA crystal was obtained without further treatment.•In-situ formation of AgNPs from TPCA-Ag+ was used for dopamine sensing.•The probe showed high sensitivity and selectivity for dopamine.Carbon dots derived from citric acid and amines have been gaining considerable attention due to their high quantum efficiency, but there are researches proven the presence of small fluorescent molecules in those materials. In this work, with proper control of the synthetic conditions, highly fluorescent 5-oxo-3,5-dihydro-2H-thiazolo[3,2-a]pyridine-7-carboxylic acid (TPCA) as nice needle-like crystals were harvested by a simple one-step hydrothermal method directly based on the reaction of citric acid and cysteamine hydrochloride. The proposed synthesis route does not need extra complicated purification process. The yield of TPCA was 46.9% and the quantum yield was as high as 83.2%. Experimental results confirmed that TPCA possesses all advantages of carbon dots reported previously with similar starting materials. In addition, a novel and effective fluorescent probe, TPCA-Ag+, was designed for sensitive and selective sensing of dopamine (DA) based on in-situ formation of sliver nanoparticles. The calibration curve for DA was linear up to 0.4 μmol/L, and a detection limit of 0.75 nmol/L was attained. The method was successfully applied to the determination of DA in dopamine hydrochloride injection and urine samples and the standard addition recoveries were in a range of 87.2–102.8%.
Co-reporter:Ruonan Li;Yunlong Shao;Yanmin Yu;Guangsheng Guo
Chemical Communications 2017 vol. 53(Issue 29) pp:4104-4107
Publication Date(Web):2017/04/06
DOI:10.1039/C7CC00799J
A picoflow high performance liquid chromatography (pico-HPLC) system was developed, which could directly pipette femtoliter samples using a separation column tip driven by an electroosmotic pump. Amino acid enantiomers were separated in the 900 nm I.D. porous layer open tubular column at a flow rate of 13.50 pL min−1.
Co-reporter:Ruonan Li;Dongtang Zhang;Yingyan Zhou
Science China Chemistry 2016 Volume 59( Issue 6) pp:746-751
Publication Date(Web):2016 June
DOI:10.1007/s11426-016-5581-4
Binuclear iron phthalocyanine/reduced graphene oxide (bi-FePc/RGO) nanocomposite with good electrocatalytic activity for ORR in alkaline medium was prepared in one step. High angle annular dark field image scanning transmission electron microscopy (HAADF-STEM) and energy dispersive X-ray spectroscopy element mapping results show bi-FePc was uniformly distributed on RGO. An obvious cathodic peak located at about −0.23 V (vs. SCE) in CV and an onset potential of −0.004 V (vs. SCE) in LSV indicate the as-prepared bi-FePc/RGO nanocomposite possesses high activity which is closed to Pt/C for ORR. The ORR on bi-FePc/RGO nanocomposite follows four-electron transfer pathway in alkaline medium. Compared with Pt/C, there is only a slight decrease (about 0.02 V vs. SCE) for bi-FePc/RGO nanocomposite when the methanol exists. The excellent activity and methanol tolerance in alkaline solutions proves that bi-FePc/RGO nanocomposite could be considered as a promising cathode catalyst for alkaline fuel cells.
Co-reporter:Fuxiang Wu;Dongtang Zhang;Manhua Peng; Zhihui Yu; Xiayan Wang; Guangsheng Guo; Yugang Sun
Angewandte Chemie International Edition 2016 Volume 55( Issue 16) pp:4952-4956
Publication Date(Web):
DOI:10.1002/anie.201600081
Abstract
Developing new synthetic methods for carbon supported catalysts with improved performance is of fundamental importance in advancing proton exchange membrane fuel cell (PEMFC) technology. Continuous-flow, microfluidic reactions in capillary tube reactors are described, which are capable of synthesizing surfactant-free, ultrafine PtSn alloyed nanoparticles (NPs) on various carbon supports (for example, commercial carbon black particles, carbon nanotubes, and graphene sheets). The PtSn NPs are highly crystalline with sizes smaller than 2 nm, and they are highly dispersed on the carbon supports with high loadings up to 33 wt %. These characteristics make the as-synthesized carbon-supported PtSn NPs more efficient than state of the art commercial Pt/C catalysts applied to the ethanol oxidation reaction (EOR). Significantly enhanced mass catalytic activity (two-times that of Pt/C) and improved stability are obtained.
Co-reporter:Fuxiang Wu;Dongtang Zhang;Manhua Peng; Zhihui Yu; Xiayan Wang; Guangsheng Guo; Yugang Sun
Angewandte Chemie 2016 Volume 128( Issue 16) pp:5036-5040
Publication Date(Web):
DOI:10.1002/ange.201600081
Abstract
Developing new synthetic methods for carbon supported catalysts with improved performance is of fundamental importance in advancing proton exchange membrane fuel cell (PEMFC) technology. Continuous-flow, microfluidic reactions in capillary tube reactors are described, which are capable of synthesizing surfactant-free, ultrafine PtSn alloyed nanoparticles (NPs) on various carbon supports (for example, commercial carbon black particles, carbon nanotubes, and graphene sheets). The PtSn NPs are highly crystalline with sizes smaller than 2 nm, and they are highly dispersed on the carbon supports with high loadings up to 33 wt %. These characteristics make the as-synthesized carbon-supported PtSn NPs more efficient than state of the art commercial Pt/C catalysts applied to the ethanol oxidation reaction (EOR). Significantly enhanced mass catalytic activity (two-times that of Pt/C) and improved stability are obtained.
Co-reporter:Manhua Peng;Biao Li;Huijun Yan;Dongtang Zhang; Xiayan Wang; Dingguo Xia; Guangsheng Guo
Angewandte Chemie 2015 Volume 127( Issue 22) pp:6552-6556
Publication Date(Web):
DOI:10.1002/ange.201411917
Abstract
Sodium-ion batteries are a very promising alternative to lithium-ion batteries because of their reliance on an abundant supply of sodium salts, environmental benignity, and low cost. However, the low rate capability and poor long-term stability still hinder their practical application. A cathode material, formed of RuO2-coated Na3V2O2(PO4)2F nanowires, has a 50 nm diameter with the space group of I4/mmm. When used as a cathode material for Na-ion batteries, a reversible capacity of 120 mAh g−1 at 1 C and 95 mAh g−1 at 20 C can be achieved after 1000 charge–discharge cycles. The ultrahigh rate capability and enhanced cycling stability are comparable with high performance lithium cathodes. Combining first principles computational investigation with experimental observations, the excellent performance can be attributed to the uniform and highly conductive RuO2 coating and the preferred growth of the (002) plane in the Na3V2O2(PO4)2F nanowires.
Co-reporter:Manhua Peng;Biao Li;Huijun Yan;Dongtang Zhang; Xiayan Wang; Dingguo Xia; Guangsheng Guo
Angewandte Chemie International Edition 2015 Volume 54( Issue 22) pp:6452-6456
Publication Date(Web):
DOI:10.1002/anie.201411917
Abstract
Sodium-ion batteries are a very promising alternative to lithium-ion batteries because of their reliance on an abundant supply of sodium salts, environmental benignity, and low cost. However, the low rate capability and poor long-term stability still hinder their practical application. A cathode material, formed of RuO2-coated Na3V2O2(PO4)2F nanowires, has a 50 nm diameter with the space group of I4/mmm. When used as a cathode material for Na-ion batteries, a reversible capacity of 120 mAh g−1 at 1 C and 95 mAh g−1 at 20 C can be achieved after 1000 charge–discharge cycles. The ultrahigh rate capability and enhanced cycling stability are comparable with high performance lithium cathodes. Combining first principles computational investigation with experimental observations, the excellent performance can be attributed to the uniform and highly conductive RuO2 coating and the preferred growth of the (002) plane in the Na3V2O2(PO4)2F nanowires.
Co-reporter:Lei Liu;Vijaykumar Veerappan;Yuzhi Bian;Guangsheng Guo
Science China Chemistry 2015 Volume 58( Issue 10) pp:1605-1611
Publication Date(Web):2015 October
DOI:10.1007/s11426-015-5384-z
We have previously developed bare narrow-bore capillary chromatography. In this work, high-performance DNA separation was realized for a size range of 10–800 base pairs (bp) utilizing bare narrow-bore capillary chromatography with 750 nm-radius capillaries. Separation behavior of double-stranded DNA (dsDNA) fragments was investigated over a range of eluent concentrations and elution pressures. DNA molecules were hydrodynamically separated in a size-dependent manner in free solution without any sieving matrices, with the longer fragments being eluted out from the capillary earlier. It was found that the eluent concentration variously influenced the transport behavior for different-sized DNA fragments depending upon the configuration of DNA molecules and the association of counterions. Ionic strength of the solutions strongly impacted DNA persistence length. Enhanced elution pressure could shorten analysis time with a slight loss in resolution. Excellent efficiency of two million theoretical plates per meter was achieved, which indicates the enormous potential of bare narrow-bore capillary chromatography for the analysis of DNA fragments. These findings would be useful in understanding the transport behavior of DNA fragments in confined dimensions for chromatography in free solution.
Co-reporter:Lei Liu, Vijaykumar Veerappan, Qiaosheng Pu, Chang Cheng, Xiayan Wang, Liping Lu, Randy D. Allen, and Guangsheng Guo
Analytical Chemistry 2014 Volume 86(Issue 1) pp:729
Publication Date(Web):November 24, 2013
DOI:10.1021/ac403190a
A high-resolution, rapid, and economical hydrodynamic chromatographic (HDC) method for large DNA separations in free solution was developed using narrow (5 μm diameter), bare open capillaries. Size-based separation was achieved in a chromatographic format with larger DNA molecules being eluting faster than smaller ones. Lambda DNA Mono Cut Mix was baseline-separated with the percentage resolutions generally less than 9.0% for all DNA fragments (1.5 to 48.5 kbp) tested in this work. High efficiencies were achieved for large DNA from this chromatographic technique, and the number of theoretical plates reached 3.6 × 105 plates for the longest (48.5 kbp) and 3.7 × 105 plates for the shortest (1.5 kbp) fragments. HDC parameters and performances were also discussed. The method was further applied for fractionating large DNA fragments from real-world samples (SacII digested Arabidopsis plant bacterial artificial chromosome (BAC) DNA and PmeI digested Rice BAC DNA) to demonstrate its feasibility for BAC DNA finger printing. Rapid separation of PmeI digested Rice BAC DNA covering from 0.44 to 119.041 kbp was achieved in less than 26 min. All DNA fragments of these samples were baseline separated in narrow bare open capillaries, while the smallest fragment (0.44 kbp) was missing in pulsed-field gel electrophoresis (PFGE) separation mode. It is demonstrated that narrow bare open capillary chromatography can realize a rapid separation for a wide size range of DNA mixtures that contain both small and large DNA fragments in a single run.
Co-reporter:Xin Chen;Xiaoming Hu;Li An;Nanlin Zhang;Dingguo Xia;Xia Zuo
Electrocatalysis 2014 Volume 5( Issue 1) pp:68-74
Publication Date(Web):2014 January
DOI:10.1007/s12678-013-0164-z
The electrochemical reduction approach has been suggested as a promising method for detoxification of chlorine-containing aromatic hydrocarbons. In this study, the electrocatalytic dechlorination of atrazine was studied by using a non-noble catalyst, binuclear iron phthalocyanine coated onto multi-walled carbon nanotubes (bi-FePc/MWNT). Both experimental and theoretical results indicate that dechlorination of atrazine occurs rapidly on bi-FePc/MWNT electrode. The reaction depends on the adsorption of the chlorinated organic compound on the electrode surface and the reaction rate with hydroxy. By liquid chromatography–tandem mass spectrometer technique, the dechlorination product of atrazine can be assigned to 2-hydroxy-4-ethylamino-6-isopropylamino-1,3,5-triazine, which could be disposed by more convenient and economic biodegradation method.
Co-reporter:Zaifang Zhu, Lei Liu, Wei Wang, Joann J. Lu, Xiayan Wang and Shaorong Liu
Chemical Communications 2013 vol. 49(Issue 28) pp:2897-2899
Publication Date(Web):25 Feb 2013
DOI:10.1039/C3CC40728D
We report a novel approach for effectively separating DNA molecules in free solution. The method uses a bare narrow open capillary without any sieving matrices to resolve a wide size-range of DNA fragments at efficiencies of more than a million plates per meter routinely.
Co-reporter:Xiayan Wang, Lei Liu, Guangsheng Guo, Wei Wang, Shaorong Liu, Qiaosheng Pu, Purnendu K. Dasgupta
TrAC Trends in Analytical Chemistry 2012 Volume 35() pp:122-134
Publication Date(Web):May 2012
DOI:10.1016/j.trac.2012.01.005
DNA molecules are usually separated by gel electrophoresis. While gels help resolve DNA, the polymers bring problems to the analysis (e.g., difficulty in automating and poor reproducibility). One way to eliminate these problems completely is to separate DNA in free solutions. However, DNA fragments cannot normally be resolved in a free solution by electrophoresis because the electrophoretic mobilities of these molecules have similar charge-to-mass ratios, especially when the fragments are large.Efforts have been invested in free-solution DNA separations and a number of approaches (e.g., high-performance liquid chromatography, end-labeled free-solution electrophoresis, entropic traps, and DNA prism) have been successfully developed. Very recently, a new technique, called bare narrow capillary-open tubular chromatography (BaNC-OTC), was developed and can resolve a wide range of sizes of DNA in a few minutes.In this article, we review the significant progress on free-solution DNA separations, with emphasis on the most recent, advanced developments.Highlights► We review progress in DNA separations in free solution. ► In particular, we introduce a new technique for DNA separations in free solution. ► We discuss potential applications of developments of DNA separations in free solution.
Co-reporter:Chiyang He, Joann J. Lu, Zhijian Jia, Wei Wang, Xiayan Wang, Purnendu K. Dasgupta, and Shaorong Liu
Analytical Chemistry 2011 Volume 83(Issue 7) pp:2430
Publication Date(Web):March 4, 2011
DOI:10.1021/ac200156s
A micropump provides flow and pressure for a lab-on-chip device, just as a battery supplies current and voltage for an electronic system. Numerous micropumps have been developed, but none is as versatile as a battery. One cannot easily insert a micropump into a nonterminal position of a fluidic line without affecting the rest of the fluidic system, and one cannot simply connect several micropumps in series to enhance the pressure output, etc. In this work we develop a flow battery (or pressure power supply) to address this issue. A flow battery consists of a +EOP (in which the liquid flows in the same direction as the field gradient) and a −EOP (in which the liquid flows opposite to the electric field gradient), and the outlet of the +EOP is directly connected to the inlet of the −EOP. An external high voltage is applied to this outlet−inlet joint via a short gel-filled capillary that allows ions but not bulk liquid flow, while the +EOP’s inlet and the −EOP’s outlet (the flow battery’s inlet and outlet) are grounded. This flow battery can be deployed anywhere in a fluidic network without electrically affecting the rest of the system. Several flow batteries can be connected in series to enhance the pressure output to drive HPLC separations. In a fluidic system powered by flow batteries, a hydraulic equivalent of Ohm’s law can be applied to analyze system pressures and flow rates.
Co-reporter:Dongtang Zhang; Fuxiang Wu; Manhua Peng; Xiayan Wang; Dingguo Xia;Guangsheng Guo
Journal of the American Chemical Society () pp:
Publication Date(Web):May 1, 2015
DOI:10.1021/jacs.5b01088
Ordered intermetallic nanomaterials are of considerable interest for fuel cell applications because of their unique electronic and structural properties. The synthesis of intermetallic compounds generally requires the use of high temperatures and multiple-step processes. The development of techniques for rapid phase- and size-controlled synthesis remains a formidable challenge. The intermetallic compound Pt1Bi2 is a promising candidate catalyst for direct methanol fuel cells because of its high catalytic activity and excellent methanol tolerance. In this work, we explored a one-step, facile and ultrafast phase- and size-controlled process for synthesizing ordered Pt–Bi intermetallic nanoparticles (NPs) within seconds in microfluidic reactors. Single-phase Pt1Bi1 and Pt1Bi2 intermetallic NPs were prepared by tuning the reaction temperature, and size control was achieved by modifying the solvents and the length of the reaction channel. The as-prepared Pt–Bi intermetallic NPs exhibited excellent methanol tolerance capacity and high electrocatalytic activity. Other intermetallic nanomaterials, such as Pt3Fe intermetallic nanowires with a diameter of 8.6 nm and Pt1Sn1 intermetallic nanowires with a diameter of 6.3 nm, were also successfully synthesized using this method, thus demonstrating its feasibility and generality.
Co-reporter:Ruonan Li, Yunlong Shao, Yanmin Yu, Xiayan Wang and Guangsheng Guo
Chemical Communications 2017 - vol. 53(Issue 29) pp:NaN4107-4107
Publication Date(Web):2017/03/21
DOI:10.1039/C7CC00799J
A picoflow high performance liquid chromatography (pico-HPLC) system was developed, which could directly pipette femtoliter samples using a separation column tip driven by an electroosmotic pump. Amino acid enantiomers were separated in the 900 nm I.D. porous layer open tubular column at a flow rate of 13.50 pL min−1.
Co-reporter:Zaifang Zhu, Lei Liu, Wei Wang, Joann J. Lu, Xiayan Wang and Shaorong Liu
Chemical Communications 2013 - vol. 49(Issue 28) pp:NaN2899-2899
Publication Date(Web):2013/02/25
DOI:10.1039/C3CC40728D
We report a novel approach for effectively separating DNA molecules in free solution. The method uses a bare narrow open capillary without any sieving matrices to resolve a wide size-range of DNA fragments at efficiencies of more than a million plates per meter routinely.
