Renmin Liu

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Organization: Liaocheng University
Department: Shandong Key Laboratory of Chemical Energy-storage and Novel Cell Technology
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Co-reporter:Zhenhua Yan, Min Wang, Jifeng Liu, Renmin Liu, Jinsheng Zhao
Electrochimica Acta 2014 Volume 141() pp:331-339
Publication Date(Web):20 September 2014
DOI:10.1016/j.electacta.2014.06.137
•Glycerol is used as an efficient stabilizer and solvent to synthesis PtxFe alloy.•PtxFe alloy is prepared by simple two-step at room temperature;.•Pt3-Fe/C show the best ORR catalytic performance in both acidic and neutral media;.•PtxFe alloy enhanced ORR activity and durability in microbial fuel cells.Insufficient catalytic activity and durability are the most challenging issues in the commercial deployment of low-temperature fuel cells. In an effort to address these barriers, three carbon-supported PtxFe alloy electrocatalysts with varying Pt:Fe atom ratios (Pt3-Fe/C, Pt2-Fe/C, Pt-Fe/C) were prepared by simple NaBH4 reduction in glycerol at room temperature. All of the prepared PtxFe nanoparticles (NPs) are highly dispersed on a carbon support and show a single-phase face-centered cubic structure with a particle size of approximately 2 nm. The electrocatalytic performances of the synthesized PtxFe alloy catalysts were compared with that of commercial Pt/C by cyclic voltammetry and linear sweep voltammetry; among these NPs, the Pt3-Fe/C catalyst exhibits the highest activity and the best stability for oxygen reduction reaction (ORR) in both acidic and neutral media. As the cathode catalyst, the maximum power density produced from microbial fuel cell with Pt3-Fe/C (1680 ± 15 mW m−2) was 18% higher than that with conventional Pt/C (1422 ± 18 mW m−2), and the stability of Pt3-Fe/C was greatly improved.
Co-reporter:Yan Tang, Ailing Sun, Renmin Liu, Yongqing Zhang
Analytica Chimica Acta 2013 Volume 767() pp:148-154
Publication Date(Web):12 March 2013
DOI:10.1016/j.aca.2013.01.001
A reversed phase high performance liquid chromatography (RP-HPLC) method for simultaneous determination of fangchinoline (FAN) and tetrandrine (TET) in Stephania tetrandra S. Moore was established by using 1-hexyl-3-methylimidazolium tetrafluoroborate as the mobile phase additives in this paper. Four types of 1-alkyl-3-methylimidazolium-based ionic liquids (ILs) were used as additives of the mobile phase to separate FAN and TET by RP-HPLC. The effects of the length of the alkyl group on the imidazolium ring and its counterion, the concentrations of IL and the pH of the mobile phase, which influenced the chromatographic behaviors of FAN and TET, were investigated in detail. The linearity, sensitivity, accuracy and repeatability of the proposed method were also investigated. The probable mechanism of the separation with ILs as the mobile phase additives was explored and discussed.Graphical abstractHighlights► ILs is used as the mobile phase additives to determine fangchinoline and tetrandrine. ► Effects of alkylgroup, counterion, concentrations of IL and pH were investigated. ► The mechanism of the separation with ILs as the mobile phase additives was discussed.
Co-reporter:Qingping Duanmu;Aifeng Li;Ailing Sun;Xiaopeng Li
Journal of Separation Science 2010 Volume 33( Issue 12) pp:1746-1751
Publication Date(Web):
DOI:10.1002/jssc.200900872

Abstract

A new high-speed counter-current chromatography method for semi-preparative separation and purification of alkaloids from embryo of the seed of Nelumbo nucifera Gaertn was developed by using pH-gradient elution mode. Diethyl ether was used as the stationary phase of the two-phase solvent system and Na2HPO4/NaH2PO4 buffer solution with pH values of 7.5 and 7.2 in gradient mode as the mobile phase. Consequently, 33 mg of liensinine, 42 mg of isoliensinine, and 67 mg of neferine were obtained from 200 mg of crude extracts. The purities of them were all over 98% as determined by HPLC area normalization method, and the structures were identified by 1H-NMR and 13C-NMR.

Co-reporter:Renmin Liu;Lili Xu;Aifeng Li ;Ailing Sun
Journal of Separation Science 2010 Volume 33( Issue 8) pp:1058-1063
Publication Date(Web):
DOI:10.1002/jssc.200900612

Abstract

A preparative high-speed counter-current chromatography method for isolation and purification of flavonoid compounds from Oroxylum indicum was successfully established by using ionic liquids as the modifier of the two-phase solvent system. Two flavonoid compounds including baicalein-7-O-diglucoside and baicalein-7-O-glucoside were purified from the crude extract of O. indicum by using ethyl acetate–water–[C4mim][PF6] (5:5:0.2, v/v) as two-phase solvent system. 36.4 mg of baicalein-7-O-diglucoside and 60.5 mg of baicalein-7-O-glucoside were obtained from 120 mg of the crude extract. Their purities were 98.7 and 99.1%, respectively, as determined by HPLC area normalization method. The chemical structures of the isolated compounds were identified by 1H-NMR and 13C-NMR.

Co-reporter:Lili Xu;Aifeng Li;Ailing Sun
Journal of Separation Science 2010 Volume 33( Issue 1) pp:31-36
Publication Date(Web):
DOI:10.1002/jssc.200900528

Abstract

A preparative high-speed countercurrent chromatography method for isolation and purification of neomangiferin and mangiferin from Rhizoma anemarrhenae was successfully established by using ionic liquids as the modifier of the two-phase solvent system. Neomangiferin and mangiferin were purified from the crude extract of R. anemarrhenae by using ethyl acetate-water-[C4mim][PF6] (5:5:0.2 v/v) as two-phase solvent system. In total, 22.5 mg of neomangiferin and 70.6 mg of mangiferin were obtained from 150 mg of the crude extract. The purities of neomangiferin and mangiferin were 97.2 and 98.1%, respectively, as determined by HPLC. The chemical structures of the isolated compounds were identified by 1H-NMR and 13C-NMR.

Co-reporter:Yanyan Huang;Ailing Sun;Yuanying Qi
Journal of Separation Science 2008 Volume 31( Issue 2) pp:283-287
Publication Date(Web):
DOI:10.1002/jssc.200700430

Abstract

A chromatographic method for isolation and purification of chemical constituents from the well-known traditional Chinese drug Da-huang (roots of Rheum officinale Baill.) was established by using 12% cross-linked agarose gel, Superose 12, as the separation media. A two-step separation procedure is employed. Sixty five percent methanol was used as the eluent for separation of cinnamic acid, rhein, physcion and emodin form Da-huang crude extract. The fraction containing aloe-emodin and chrysophanol was then separated by using 55% methanol containing 0.5% acetic acid as the eluent. As a result, cinnamic acid and five kinds of hydroxyanthraquinones including rhein, aloe-emodin, chrysophanol, physcion and emodin were obtained. The retention behavior of hydroxyanthraquinones on Superose 12 was also studied. The retention of hydroxyanthraquinones on Superose 12 is based on a mixture of hydrogen bonding and hydrophobic interactions between the hydroxyl groups of the hydroxyanthraquinones and the residues of the cross-linking reagents used in the manufacturing process of Superose 12.

Co-reporter:Yuanying Qi;Ailing Sun;Hongyan Xie
Journal of Separation Science 2007 Volume 30(Issue 12) pp:1870-1874
Publication Date(Web):12 JUN 2007
DOI:10.1002/jssc.200600528

A chromatographic method using 12% cross-linked agarose gel Superose 12 as the separation medium was developed for isolation and purification of the chemical constituents from the pericarp of Sophora japonica L. The mobile phase used for the separation was 2% acetic acid and 7% acetic acid in gradient elution. As a result, eight compounds including four kinds of flavonoids and four kinds of isoflavonoids were obtained in a one-step separation. A straightforward explanation of the separation mechanism of flavonoids and isoflavonoids on Superose 12 is also given. The flavonoids and isoflavonoids are retained on Superose 12 by a combination of hydrogen bonding and hydrophobic interactions between the hydroxyl groups of aglycone and the residues of the cross-linking reagents used in the manufacture of Superose 12.

2-Propenoic acid,3-(3,4-dihydroxyphenyl)-, phenylmethyl ester
(2S,3S,4S,5R,6S)-3,4,5-trihydroxy-6-(5-hydroxy-8-methoxy-4-oxo-2-phenylchromen-7-yl)oxyoxane-2-carboxylic acid
3',5-Dihydroxy-7-(β-D-glucopyranosyloxy)-4'-methoxyflavone
Cobalt, compd. with platinum (1:1)
2-Methyloxyphenol
2,9,10-trimethoxy-5,6-dihydroisoquinolino[2,1-b]isoquinolin-7-ium-3-ol
Berberine
Methylene, dichloro-(6CI,8CI,9CI)
Cosmosiin
7,8-Dihydroxy-6-methoxy-2H-chromen-2-one