The Experts below are selected from a list of 276 Experts worldwide ranked by ideXlab platform
G. Li - One of the best experts on this subject based on the ideXlab platform.
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Mono-sized and single-walled 4 Å carbon nanotubes
Chemical Physics Letters, 2001Co-Authors: Ning Wang, G. Li, Zikang TangAbstract:Mono-sized and single-walled carbon nanotubes (SWNTs), synthesized by pyrolyzing Tripropylamine molecules in the channels of porous zeolite single crystals, have been directly observed by high-resolution transmission electron microscopy (HRTEM). As confirmed by imaging simulations, SWNTs measure just 4 A in diameter. HRTEM images of these tiny SWNTs show simple contrast of paired fringes. The spacing and shape of the paired fringes are sensitive to the focus condition of HRTEM. When imaging is done at the Scherzer defocus condition, the spacings between the paired dark fringes (outside-to-outside) represent the actual diameters of SWNTs.
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Mono-sized single-wall carbon nanotubes formed in channels of AlPO4-5 single crystal
Applied Physics Letters, 1998Co-Authors: Zikang Tang, Jiannong Wang, Jiesheng Chen, G. LiAbstract:An alternative approach to the synthesis of mono-sized and parallel-aligned single-wall carbon nanotubes (SWCNs) is reported. The SWCNs are formed in 0.73 nm sized channels of microporous aluminophosphate crystallites by pyrolysis of Tripropylamine molecules in the channels. They are characterized through transmission electron microscopy, polarized Raman scattering, and electrical transport measurements. Our results would open a door to further detailed studies on the intrinsic properties of carbon nanotubes now in progress.
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Mono-sized single-wall carbon nanotubes formed in channels of AlPO[sub 4]-5 single crystal
Applied Physics Letters, 1998Co-Authors: Z. K. Tang, H D Sun, Junling Wang, G. LiAbstract:An alternative approach to the synthesis of mono-sized and parallel-aligned single-wall carbon nanotubes (SWCNs) is reported. The SWCNs are formed in 0.73 nm sized channels of microporous aluminophosphate crystallites by pyrolysis of Tripropylamine molecules in the channels. They are characterized through transmission electron microscopy, polarized Raman scattering, and electrical transport measurements. Our results would open a door to further detailed studies on the intrinsic properties of carbon nanotubes now in progress.
Guobao Xu - One of the best experts on this subject based on the ideXlab platform.
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electrochemiluminescence of luminol Tripropylamine system
Electrochimica Acta, 2016Co-Authors: Saima Hanif, Peter John, Shimeles Addisu Kitte, Guobao XuAbstract:Abstract Hydrogen peroxide is a dominating coreactant of most luminol electrochemiluminescence (ECL) studies though it is unstable and sensitive to many metal ions. Tripropylamine is an eminent coreactant of tris(2,2'-bipyridine)ruthenium ECL. In comparison with H 2 O 2, Tripropylamine is much more stable. In this study, Tripropylamine has been exploited as a new coreactant of luminol ECL for the first time. The emission spectrum reveals that the ECL peak was aroused by excited 3-aminophthalate. Under optimized conditions, a biphasic linear relationship is obtained between the ECL intensities and luminol concentrations in the presence of 10 mM Tripropylamine over the range of 1.0 × 10 −11 −1.0 × 10 −7 M and 1.0 × 10 −7 −1.0 × 10 −4 M with a detection limit of 6.9 × 10 −12 M. The detection of Tripropylamine showed a linear relationship between ECL intensities and Tripropylamine concentrations in the range of 1.0 × 10 −6 to 1.0 × 10 −2 M with a detection limit of 7.7 × 10 −7 M. Compared to luminol-H 2 O 2 ECL, luminol-Tripropylamine ECL system displays not only high stability but also high sensitivity. Hence, it shows great potential in many fields including immunoassay or non-immunoassay diagnostic, clinical, pharmaceutical, environmental and food analysis in the future.
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Electrogenerated chemiluminescence of tris(2,2'-bipyridine)ruthenium(II) using N -(3-aminopropyl)diethanolamine as coreactant
Analytical and Bioanalytical Chemistry, 2016Co-Authors: Shimeles Addisu Kitte, Chao Wang, Suping Li, Yuriy T. Zholudov, Liming Qi, Jianping Li, Guobao XuAbstract:Coreactant plays a critical role for the application of electrochemiluminescence (ECL). Herein, N-(3-aminopropyl)diethanolamine (APDEA) has been explored as a potential coreactant for enhancing tris(2,2'-bipyridyl)ruthenium(II) ECL. It is much more effective than Tripropylamine at gold and platinum electrodes although it has one primary amine group besides a tertiary amine group. The presence of primary amine group and hydroxyl groups in APDEA promotes the oxidation rates of amine and thus remarkably increases ECL intensity. The ECL intensities of the Ru(bpy)32+/APDEA system are approximately 10 and 36 times stronger than that of Ru(bpy)32+/Tripropylamine system and about 1.6 and 1.14 times stronger than that of Ru(bpy)32+/N-butyldiethanolamine system at Au and Pt electrodes, respectively. The ECL intensity of the Ru(bpy)32+/APDEA system is 2.42 times stronger than that of Ru(bpy)32+/N-butyldiethanolamine at glassy carbon electrodes.
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Tris(2,2′-bipyridyl)ruthenium(II) electrochemiluminescent detection of coreactants containing aromatic diol group by the interaction between diol and borate anion
Electrochemistry Communications, 2007Co-Authors: Haijuan Li, Guobao XuAbstract:Previous studies show that aromatic diols inhibited Ru(bpy)(3)(2+) electrochemiluminescence (ECL), and all reported Ru(bpy)(3)(2+) ECL methods for the determination of aromatic diols-containing coreactants are based on inhibition of Ru(bpy)(3)(2+)/Tripropylamine ECL. In this study, the interaction between diol and borate anion was exploited for Ru(bpy)(3)(2+) ECL detection of coreactants containing aromatic diol group using epinephrine as a model analyte. The interaction prevented from the inhibition of Ru(bpy)(3)(2+) ECL by aromatic diol group of epinephrine. As a result, epinephrine was successfully detected in the absence of Tripropylamine simply by using borate buffer solution as the supporting electrolyte. Under the optimum conditions, the log of the ECL intensity increases linearly with the log of epinephrine concentrations over the concentration range of 1.0x10(-9)-1.0x10(-4) M. The detection limit is 5.0x10(-10) M at a signal-to-noise ratio of three. The proposed method exhibit wider dynamic range and better detection limit than that by inhibited Ru(bpy)(3)(2+) ECL method. The relative standard deviation for 14 consecutive determinations of 5 mu M epinephrine was 3.5%. The strategy by interaction with borate anion or boronate derivatives is promising for the determination of coreactants containing aromatic diol group or aromatic hydroxyl acid group. Such interaction can also be used to avoid interference from aromatic diols or aromatic hydroxyl acids.
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Electrochemistry and electrochemiluminescence of stable tris(2,2'-bipyridyl)ruthenium(II) monolayer assembled on benzene sulfonic acid modified glassy carbon electrode.
Talanta, 2001Co-Authors: Haiyan Wang, Guobao Xu, Shaojun DongAbstract:An electrochemically stable monolayer of tris(2,2'-bipyridyl)ruthenium(II) was obtained for the first time. It was based on the electrostatic attachment of Ru(bpy)(3)(2+) to the benzene sulfonic acid monolayer film, which was covalently bound onto glassy carbon electrode by the electrochemical reduction of diazobenzene sulfonic acid. The surface-confined Ru(bpy)(3)(2+) underwent reversible surface process, and reacted with the coreactant, Tripropylamine, to produce electrochemiluminescence. In view of the stability of the electrode, the results strongly suggested that light was emitted from the surface-confined Ru(bpy)(3)(2+), not from the detached Ru(bpy)(3)(2+). The Ru(bpy)(3)(2+) modified electrode was used to the determination of Tripropylamine. It showed good linearity in the concentration range from 5 muM to 1 muM with a detection limit of 1 muM (S/N = 4). The good stability of the Ru(bpy)(3)(2+) modified electrode also showed that the benzene sulfonic acid monolayer film prepared can be served as an excellent support to construct multilayers. (C) 2001 Elsevier Science B.V. All rights reserved.
Hongwei Du - One of the best experts on this subject based on the ideXlab platform.
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a novel tris 2 2 bipyridine ruthenium ii Tripropylamine cathodic electrochemiluminescence in acetonitrile for the indirect determination of hydrogen peroxide
Talanta, 2009Co-Authors: Baiqing Yuan, Hongwei DuAbstract:A novel tris(2,2'-bipyridine)ruthenium(II) (Ru(bpy)(3)(2+)) cathodic electrochemiluminescence (ECL) was generated at -0.78 V at the Pt electrode in acetonitrile (ACN), which suggested that the cathodic ECL differed from conventional cathodic ECL. It was found that Tripropylamine (TPrA) could enhance this cathodic ECL and the linear range (log-log plot) was 0.2 microM-0.2mM. In addition, hydrogen peroxide (H(2)O(2)) could inhibit the cathodic ECL and was indirectly detected with the linear range of 27-540 microM. The RSD (n=12) of the ECL intensity in the presence of 135 microM H(2)O(2) was 0.87%. This method was also demonstrated for the fast determination of H(2)O(2) in disinfectant sample and satisfactory results were obtained.
Skylar A. Martin - One of the best experts on this subject based on the ideXlab platform.
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solid state electrogenerated chemiluminescence from gel entrapped ruthenium ii tris bipyridine and Tripropylamine
Chemistry of Materials, 1999Co-Authors: Maryanne M. Collinson, Jacob S Taussig, Skylar A. MartinAbstract:A novel approach for the electrogeneration of stable light emission in a solid host structure under room conditions is described. In this work, the chemiluminescent precursors, ruthenium(II) tris(bipyridine) (Ru(bpy)32+) and Tripropylamine (TPA), were trapped in a porous silicate host matrix along with an electrode assembly. When the electrode potential was scanned or stepped to a potential sufficient to oxidize gel-entrapped TPA and Ru(bpy)32+, electrochemiluminescence (ECL) was observed. The solid-state ECL spectrum was identical to the fluorescence spectrum of gel-entrapped Ru(bpy)32+. The intensity of the emission depends on the amount of TPA and Ru(bpy)32+ in the gel as well as the size of the electrode. When an ultramicroelectrode (microband or microdisk) was used to generate the ECL, the resultant emission was found to be remarkably stable. Little drop in intensity was observed upon continuous application of ca. 1.2 V for 2−12 h. In direct contrast, the ECL dropped significantly at a large electrod...
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Solid-state electrogenerated chemiluminescence in sol–gel derived monoliths
Chemical Communications, 1999Co-Authors: Maryanne M. Collinson, Skylar A. MartinAbstract:Stable solid-state electrogenerated chemiluminescence has been achieved by trapping the chemiluminescent precursors, ruthenium(II) tris(bipyridine) and Tripropylamine, in a porous silicate host matrix prepared by the sol–gel process and exciting them electrochemically via an immobilized microelectrode assembly.
Zikang Tang - One of the best experts on this subject based on the ideXlab platform.
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Carbonization Mechanism of Tetrapropylammonium-hydroxide in Channels of AlPO4-5 Single Crystals
Chemistry of Materials, 2006Co-Authors: Jian Pang Zhai, Zikang Tang, Z.m. Li, Irene Ling Li, Fu Yi Jiang, Ping Sheng, Xijun HuAbstract:We studied the carbonization mechanism of tetrapropylammonium-hydroxide (TPAOH) carbon precursors in the channels of AlPO 4 -5 crystal, with the aim of producing higher-density and better-quality 4 A carbon nanotubes. The conversion process of TPAOH was investigated by using a combination of Fourier transform infrared (PTIR) spectra, mass spectrometry, and micro-Raman spectroscopy under various pyrolysis temperatures. During the pyrolysis process, the TPAOH molecules decomposed into lighter amines with the abstraction of propylene, with the stepwise formation of Tripropylamine, dipropylamine, and n-propylamine. This leads to the formation of 0.4 nm single-walled carbon nanotubes (SWNTs) at about 723 K. The SWNTs density was found to be higher than that resulting from the carbon precursor of Tripropylamine (TPA), because of the larger number of carbon atoms in the unit cell. Thermogravimetry (TG) measurements also indicated a higher loading density (in AlPO 4 -5 crystals) for the TPAOH carbon precursors.
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Mono-sized and single-walled 4 Å carbon nanotubes
Chemical Physics Letters, 2001Co-Authors: Ning Wang, G. Li, Zikang TangAbstract:Mono-sized and single-walled carbon nanotubes (SWNTs), synthesized by pyrolyzing Tripropylamine molecules in the channels of porous zeolite single crystals, have been directly observed by high-resolution transmission electron microscopy (HRTEM). As confirmed by imaging simulations, SWNTs measure just 4 A in diameter. HRTEM images of these tiny SWNTs show simple contrast of paired fringes. The spacing and shape of the paired fringes are sensitive to the focus condition of HRTEM. When imaging is done at the Scherzer defocus condition, the spacings between the paired dark fringes (outside-to-outside) represent the actual diameters of SWNTs.
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Single-walled 4 Å carbon nanotube arrays
Nature, 2000Co-Authors: Ning Wang, Zikang Tang, Gang Li, Jingtao ChenAbstract:Here we describe the smallest carbon nanotubes possible1, prepared by the pyrolysis of Tripropylamine molecules in the channels of porous zeolite AlPO4-5 (AFI) single crystals2. These uniformly sized carbon nanotubes have a diameter of 0.4 nm and are the best example of one-dimensional quantum wires.
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Mono-sized single-wall carbon nanotubes formed in channels of AlPO4-5 single crystal
Applied Physics Letters, 1998Co-Authors: Zikang Tang, Jiannong Wang, Jiesheng Chen, G. LiAbstract:An alternative approach to the synthesis of mono-sized and parallel-aligned single-wall carbon nanotubes (SWCNs) is reported. The SWCNs are formed in 0.73 nm sized channels of microporous aluminophosphate crystallites by pyrolysis of Tripropylamine molecules in the channels. They are characterized through transmission electron microscopy, polarized Raman scattering, and electrical transport measurements. Our results would open a door to further detailed studies on the intrinsic properties of carbon nanotubes now in progress.
