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941.
Preparation of Polyaniline/Au0 Nanocomposites Modified Electrode and Application for Hydrazine Detection 下载免费PDF全文
Meng Xin Hailian Lin Jianmao Yang Mengni Chen Xiaoyu Ma. Jianyun Liu 《Electroanalysis》2014,26(10):2216-2223
The PANI/Au0 nanocomposite films were successfully prepared on glassy carbon electrode (GCE) using a simple alternate adsorption of water soluble polyaniline (PANI) and . The growth of the films was monitored by UV? Vis spectroscopy and cyclic voltammetry. was in‐situ reduced in the film due to the redox interaction between PANI and , without extra reductant. The ultrafine Au nanoparticles with the size of 2–4 nm were observed by transmission electron spectroscopy. The existence of zero‐valence Au nanocrystals (Au0) was confirmed by X‐ray photoelectron spectroscopy, X‐ray Diffraction and FTIR. PANI in the nano‐structured PANI/Au0 composite films displayed a good redox activity in neutral pH solution. The as‐obtained PANI/Au0/GCE presents an excellent electrocatalytic activity to hydrazine oxidation, and the mechanism of hydrazine oxidation was studied. The calibration curve on (PANI/Au0)5/GCE was obtained in the concentration range of 0.01–6 mM with the detection limit of 1 µM (S/N>3). The modified electrode has a great potential for hydrazine sensor application due to its ease of fabrication, good reproducibility and high stability. 相似文献
942.
Lei Ma Chenglin Sun Jian Ren Huangzhao Wei Peijuan Liu 《Russian Journal of Electrochemistry》2014,50(6):569-578
The feasibility of activated carbon fibers (ACFs) used as a new type of particle electrodes in 3-dimensional (3D) electrode for the electrochemical degradation of phenol wastewater was investigated for the first time. The surface morphology, textual properties and electrochemical behaviors of ACF were studied by scanning electron microscopy (SEM), N2-BET sorption and cyclic voltammograms (CVs), respectively. Compared with the commercialized granular activated carbon (GAC), ACF particle electrodes exhibited higher electrochemical oxidation performance on the mineralization of target pollutant. The identification of intermediates indicated most of oxidation products were adsorbed onto the ACFs. The detection of hydrogen peroxide and hydroxyl radicals in the reaction system suggested that the reaction mechanism was direct anodic oxidation of pollutant on ACFs if the cathode did not contact the ACFs. The operative parameters including initial concentration of substrate, applied current density and the initial aqueous pH have been scientifically studied in search of the optimum condition. Based upon the obtained results, the ACFs longevity was tested in solution at pH 2.0, revealing relatively high electrooxidation capacity and long catalyst lifetime of ACFs in acid solution. 相似文献
943.
Three types of zirconium phosphonate (org‐ZrP) with different functional groups (―COOH, ―SO3H, ―NO2) were prepared first and then added into chitosan (CS) matrix, respectively. The effect of these functional groups on structure, morphologies, and mechanical properties of chitosan films was investigated. The Fourier transform infrared spectroscopy revealed that org‐ZrP had intensely interacted with chitosan in the composites because of introducing functional groups on the fillers. The composite films filled with zirconium sulfophenylphosphonate exhibited the best mechanical properties among the three org‐ZrP fillers. These differences of reinforcement effect appeared to be caused by the difference of interfacial interactions between the org‐ZrP fillers and matrix. The stronger the interfacial interactions are, the better the reinforcement effect is. In addition, the moisture uptake (Mu) of CS/org‐ZrP‐n composite films depended on the hydrophilic property of functional groups. It was found that zirconium nitrophenyl phosphonate showed the best moisture barrier property due to its poor absorbability for water molecules. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
944.
Xin Ma Mowei Zhou Vicki H. Wysocki 《Journal of the American Society for Mass Spectrometry》2014,25(3):368-379
Ion mobility (IM) and tandem mass spectrometry (MS/MS) coupled with native MS are useful for studying noncovalent protein complexes. Collision induced dissociation (CID) is the most common MS/MS dissociation method. However, some protein complexes, including glycogen phosphorylase B kinase (PHB) and L-glutamate dehydrogenase (GDH) examined in this study, are resistant to dissociation by CID at the maximum collision energy available in the instrument. Surface induced dissociation (SID) was applied to dissociate the two refractory protein complexes. Different charge state precursor ions of the two complexes were examined by CID and SID. The PHB dimer was successfully dissociated to monomers and the GDH hexamer formed trimeric subcomplexes that are informative of its quaternary structure. The unfolding of the precursor and the percentages of the distinct products suggest that the dissociation pathways vary for different charge states. The precursors at lower charge states (+21 for PHB dimer and +27 for GDH hexamer) produce a higher percentage of folded fragments and dissociate more symmetrically than the precusors at higher charge states (+29 for PHB dimer and +39 for GDH hexamer). The precursors at lower charge state may be more native-like than the higher charge state because a higher percentage of folded fragments and a lower percentage of highly charged unfolded fragments are detected. The combination of SID and charge reduction is shown to be a powerful tool for quaternary structure analysis of refractory noncovalent protein complexes, as illustrated by the data for PHB dimer and GDH hexamer. Figure
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945.
Oscar Hernandez Peter Pulay Philippe Maître Béla Paizs 《Journal of the American Society for Mass Spectrometry》2014,25(9):1511-1514
Using quantum chemical calculations and infrared multiphoton dissociation (IRMPD) spectroscopy in the fingerprint and X-H stretching regions, we demonstrate here that the all-Ala b 6 fragment ion features a macrocyclic structure with C2 symmetry. For this structure, the ionizing proton is equally shared by the Ala(1) and Ala(4) amide oxygens in a Zundel-type symmetric (X…H+…X) H-bond. Figure
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946.
C. C. Ma Y. Li J. Wang D. Y. Kong C. Qin Q. Wu 《Russian Journal of Coordination Chemistry》2014,40(9):617-626
Two title rare earth metal coordination compounds, (MnH)[GdIII(Edta)(H2O)3] · 4H2O (I) and (MnH)2[Gd 2 III (H2Ttha)2] · 4H2O (II), where Mn = methylamine, H4Edta = ethylenediamine-N,N,N′,N′-tetraacetic acid, H6Ttha = triethylenetetramine-N,N,N′,N″,N′″,N′″-hexaacetic acid), have been successfully synthesized through direct heating reflux and characterized by FT-IR spectroscopy, thermal analysis and single-crystal X-ray diffraction techniques. In complex I, the Gd3+ ion is nine-coordinated by an Edta ligand and three water molecules, yielding a pseudo-monocapped square antiprismatic (MC-SAP) conformation. Complex I crystallizes in the orthorhombic crystal system with space group Fdd2. The cell dimensions are as follows: a = 19.5207(17), b = 35.387(3), c = 12.5118(11) Å, and V = 8642.8(13) Å3. The central Gd3+ ion of II is also ninecoordinate, forming tricapped trigonal prismatic (TC-TP) conformation with three amine nitrogen atoms and six oxygen atoms. Complex II crystallizes in the monoclinic crystal system with P2/c space group. The crystal data are as follows: a = 14.4301(13), b = 11.2400(11), c = 17.7102(16) Å, β = 112.606(2)°, and V = 2651.8(4) Å3. There retain outer-protonated and inner-protonated carboxyl oxygen atoms in the [Gd 2 III (H2Ttha)2]2? complex anion. In II, there are only one type of methylamine cation (MnH+) as the counter ion, which connects [Gd 2 III (H2Ttha)2]2? complex anions and lattice water molecules through hydrogen bonds, leading to the formation of 2D ladder-like layer structure. 相似文献
947.
Lude Wang Zhao Ma Shaogang Liu Zaiyin Huang 《Journal of Thermal Analysis and Calorimetry》2014,115(1):201-208
We report the one-step synthesis of zinc oxide nanomaterials with arrays and hierarchical structure at room temperature. The zinc oxide nanomaterials can be synthesized via a simple method without catalyst. Furthermore, we explained the growth mechanisms of the two systems. In situ growth experiment provided the information of thermodynamics and kinetics, and based on that, growth mechanism was given a further explanation via the curve of in situ growth. Moreover, the relations between thermodynamic functions and the potential difference can be established by the electrochemical method. Take bulk zinc oxide reference. The thermodynamic functions of nano zinc oxide such as standard molar entropy, standard molar Gibbs free energy of formation, and standard molar enthalpy of formation can be calculated. The change rules of thermodynamic functions at different reaction times evidenced the growth mechanism more deeply. This work may contribute to the analysis of growth mechanism for nanostructures and obtain the thermodynamic functions of nanomaterials. 相似文献
948.
Xiande Yang Yongqian Wang Tingting Jiang Jun Yang Yinchang Li Qun Ma 《Crystal Research and Technology》2015,50(4):338-345
In this article, dendritic‐like CdS has been prepared by a hydrothermal method using thiourea as the sulfur source, and the effects of experimental conditions on the morphologies of CdS have been investigated. The performances of CdS have been analyzed by X‐ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and the fluorescence and photodegradation properties of CdS have also been investigated. The XRD result indicates that the dendritic‐like CdS are of hexagonal phase and they are highly crystallized. Also, the FESEM results show that the ratio of raw material affects the yield of CdS, the reaction time affects the morphology of CdS. The best morphology of CdS is dendritic structures and the length is about 6 μm. The fluorescence spectrum shows three peaks at 470 nm, 513 nm and 547 nm, which indicates that the dendritic‐like CdS mainly emits green and blue fluorescence. Moreover, the dendritic‐like CdS exhibits good photocatalytic activity and its photodegradation rate to methylene blue can reach 92%. The growth mechanism for the formation of CdS with dendritic structure is also described. 相似文献
949.
Xiande Yang Yongqian Wang Zhengshu Wang Qun Ma Junhan Kong Hanxiang Jia Meihua Yu 《Crystal Research and Technology》2015,50(8):658-667
In this article, flower‐like CdS structures have been prepared by a hydrothermal method with SDBS as surfactant. The influences of different experimental conditions on the morphologies, UV‐Vis and fluorescence properties of CdS have been investigated. The performances of CdS have been analyzed by X‐ray diffraction (XRD), field emission scanning electron microscopy (FESEM), ultraviolet‐visible (UV–Vis) and room‐temperature photoluminescence (PL). The XRD result indicates that the flower‐like CdS structures are of hexagonal phase. The FESEM results indicate that the main role of SDBS is to make the CdS crystals assemble together to form the flower‐like structures. The UV–Vis results show CdS has a strong absorption in the ultraviolet region and visible‐light region. The PL results show CdS has two emission peaks, respectively at 461 nm and 553 nm. The growth mechanism for the formation of flower‐like CdS structures is also described. 相似文献
950.
The theoretical analysis of electronic structure and bonding properties of anhydrous alkali metal oxalates, based on the results of DFT FP-LAPW calculations, Bader’s QTAIM topological properties of electron density, Cioslowski and Mixon’s topological bond orders [reported in the first part of this paper by Kole?yński (doi:10.1007/s10973-013-3126-z)] and Brown’s Bond Valence Model calculations, carried out in the light of thermal decomposition pathway characteristic for these compounds are presented. The obtained results shed some additional light on the origins of the complex pathway observed during thermal decomposition process (two stage process, first the formation of respective carbonate and then decomposition to metal oxide and carbon dioxide). For all structures analyzed, strong similarities in electronic structure and bonding properties were found (ionic-covalent bonds in oxalate anion with C–C bond as the weakest one in entire structure and almost purely ionic between oxalate group and alkali metal cations), allowing us to propose the most probable pathway consisting of consecutive steps, leading to carbonate anion formation with simultaneous cationic sublattice relaxations, which results in relative ease of respective metal carbonate formation. 相似文献