Preparation and properties of sulfonated poly(ether ether ketone)s (SPEEK)/polypyrrole composite membranes for direct methanol fuel cells

Polypyrrole (Ppy) was successfully introduced into methyl substituted sulfonated poly(ether ether ketone) (SPEEK) membranes by polymerization in SPEEK solutions to improve their methanol resistance. Uniform polypyrrole (Ppy) distributed composite membranes were formed by this method by the interaction between SPEEK and Ppy. The properties of the composite membranes were characterized in detail. The composite membranes show very good proton conductive capability (25 degrees C: 0.05-0.06s cm(-1)) and good methanol resistance (25 degrees C: 5.3 x 10(-7) 1.1 x 10(-6) cm(2) s(-1)). The methanol diffusion coefficients of composite membranes are much lower than that of pure SPEEK membranes (1.5 x 10(-6) cm(2) s(-1)). The composite membranes show very good potential usage in direct methanol fuel cells (DMFCs).

Preparation and simulation of an additional catalyst layer for direct methanol fuel cell

An additional anode catalyst layer with PtRu/C was hot pressed between two Nafion (R) 112 membranes and a conventional direct methanol fuel cell (DMFC) cathode/membrane/anode assembly with the above membranes as separator was fabricated. The additional catalyst layer formed an assistant cell with the cathode to prevent methanol crossover. A simple one-dimensional mathematical model was presented to describe the performance of this new type of membrane electrode assembly system. As seen from both experimental result and model analysis, the additional catalyst layer can not only effectively prevent the methanol crossover, but also generate electrical power with the crossover methanol. The percentage of output power of the assistant cell to the total power analyzed by the model is about 40% under usual condition, which is much higher than that from experimental result, indicating the potential of the development in the DMFC designing. It was also discovered that the electrical power generated from the assistant cell with crossover methanol could take higher percentage in total electrical power when the main DMFC current density became lower.

Low temperature preparation of ceria solid solutions doubly doped with rare-earth and alkali-earth and their properties as solid oxide fuel cells

A series of solid electrolytes, (Ce(0.8)Ln(0.2))(1 - x)MxO2 - delta(Ln = La, Nd, Sm, Gd, M:Alkali-earth), were prepared by amorphous citrate gel method. XRD patterns indicate that a pure fluorite phase is formed at 800 degreesC. The electrical conductivity and the AC impedance spectra were measured. XPS spectra show that the oxygen vacancies increase owing to the MO doping, which results in the increase of the oxygen ionic transport number and conductivity. The performance of ceria-based solid electrolyte is improved. The effects of rare-earth and alkali-earth ions on the electricity were discussed. The open-circuit voltages and maximum power density of planar solid oxide fuel cell using (Ce0.8Sm0.2)(1 - 0.05)Ca0.05O2 - delta as electrolyte are 0.86 V and 33 mW . cm(-2), respectively.

Effect of properties of active carbon supports on performance of Pt/C catalysts in polymer electrolyte membrane fuel cell

The Pt/C catalysts were prepared with pine active carbon and Vulcan XC-72 active carbon as the supports. The performances of the Pt/C catalysts in polymer electrolyte membrane fuel cell were compared. The result indicates that the performance of Pt/Vulcan XC-72 is better than that of Pt/pine. The physical and chemical properties of the two active carbons were measured using several analysis techniques. It was found that the pore size, specific conductivity and the surface function group significantly influence the performance of the electrocatalyst.

Effect of rare earth element on the metabolism in rats by high resolution proton nuclear magnetic resonance spectroscopy

The high-field nuclear magnetic resonance (NMR) spectra can be used for the rapid multicomponent analysis in small amounts of biological fluids. In this paper, the effect of La (NO3)(3) on the rats' metabolism in urine was investigated by H-1 NMR analysis. The experimental groups of wistar rats were injected intraperitoneally with La(NO3)(3) at doses of 0.2, 2.0, 10 and 20mg/kg body weight. The remarkable variation of low molecular weight metabolites in urine has been identified by H-1 NMR spectra, in which dimethylamine, N, N-dimethylglycine, urea, alpha -ketoglutarate, trimethylamine N-oxide, succinate, citrate and amino acids have been suggested as NMR markers for renal damage and ethanol, lactate, taurine as the markers for liver damage. This work may assess its possible use in the early detection of biochemical changes associated with Rare Earth induced kidney and liver dysfunction.

Carbon-13 nuclear magnetic resonance spectrum simulation of pyridines and quinolines

Artificial neural network (ANN) and multiple linear regression (MLR) were used for the simulation of C-13 NMR chemical shifts of 118 central carbon atoms in 18 pyridines and quinolines. The electronic and geometric features were calculated to describe the environments of the central carbon atom. The results provided by ANN method were better than that achieved by MLR.

Studies of Gd-diethylenetriamine pentaacetic acid in boving serum albumin solution by nuclear magnetic resonance spectroscopy

In this paper, the water relaxation enhancement behavior of Gd-diethylenetriamine pentaacetic acid(DTPA) in water and in aqueous solution of bovine serum albumine(BSA) has been studied. The T-1 relaxivity of Gd-DTPA in BSA solution is higher than that in aqueous solution. The results indicate that Gd-DTPA can integrate non-covalently with BSA mainly in forms of (Gd-DTPA) . BSA, (Gd-DTPA)(2) . BSA, for which the apparent equilibrium constant is 0.026 mmol(-1).L,0.0018 mmol(-2).L-2 respectively. This method would be used to study the interactivities between protein and contrast agent.

Nuclear magnetic resonance studies on the effects of Rare Earth in rats urine

Male Wistar rats were administrated orally with La(NO3)(3) at doses of 0. 05, 0. 2, 2. 0, 10 and 20 mg/kg body weight. Urine was collected over a 24 h period after dosing. Resonances for a large number of low molecular weight metabolites were assigned in a high resolution H-1 NMR spectra of rat urine. The variation of some low molecular weight metabolites in urine provided a sensitive measurement of Rare Earth induced renal and liver lesions, in which DMA, DMG, urea, Kg, TMAO, succinate, citrate and amino acids have been suggested as NMR markers for renal damage and ethanol, lactate, taurine as the markers for liver damage. The method could be applicable to study of the toxicological effects of other compounds and drugs.

Prediction of C-13-nuclear magnetic resonance chemical shifts for aliphatic amines

Prediction of C-13-nuclear magnetic resonance chemical shifts for aliphatic amines is performed. The topological, geological and electronic descriptors are generated. To reduce the variables, the best subsets of the descriptors are obtained by using leaps-and-bounds regression analysis. The model is achieved using multiple regression with satisfactory results.

Two dimensional nuclear magnetic resonance analysis of ruthenium-(4,4'-dimethyl-2,2'-bipyridine)(2) (2,2'-bipyridine-4,4'-dicarboxylic acid) (PF6)(2)

The (1) H and C-13 NMR spectra are reported for Ru(4, 4'-dimethyl-2,2'-bipyridene)(2) (2,2'-bipyridine-4,4'-dicarboxylic acid) (PF6)(2) that can be used as a new electrochemiluminescent probe in immunoasssay and nucleic acid hybridization assay. Because of the effect ol:Ru atom ligands and complex steric configuration, it is difficult to attribute spectra of the title molecular, By using 2D (1) H-(1) H COSY and (1) H-C-13 HETCOR method, the proton and C-13 NMR spectra are assigned completely, which provides a satisfactory method to quantitative and qualitative, analysis of the title moleculer in the further study.

Two dimensional nuclear magnetic resonance analysis of bis(2,2 '-bipyridine)(2,2 '-bipyridine-4,4 '-dicarboxylic acid)ruthenium(II) hexafluorophosphate

The H-1 and C-13 nuclear magnetic resonance(NMR) spectra are reported for bis(2, 2'-bipyridine)(2, 2'-bipyridine-,4,4'-dicarboxylic acid) ruthenium(II) hexafluoruphosphate that has been used as a tagged molecule of electrochemiluminescent immunoassay. Because of the effect of Ru atom on ligands, it is difficult to assign its NMR spectra. BS' means of two dimensional H-1-H-1 COSY and H-1-C-13 COSY techniques, the H-1 and C-13 NMR spectra of bis (2, 2'-bipylidine) (2, 2'-bipyridine-4, 4-dicarboxylic acid) ruthenium(II) hexafluorophosphate are assigned completely. This provides a basis for NMR characterization of the nerv similar tagged molecules.

Analysis of 2D-nuclear magnetic resonance for Ru(2,2 '-bipyridine)(2)(4,4 '-dimethyl-2,2 '-bipyridine) (PF6)(2)

The H-1 and C-13 NMR spectra are reported for Ru(2,2'-bipyridine)(2)(4,4'-dimethyl-2,2'-bipyridine)(PF6)(2) that may be used as elechochemiluminescent species. Because of the effect of Ru atom on ligands and complex steric configuration, it is, difficult to attribute the spectra of the title molecular. By using 2D H-1-H-1 COSY and H-1-C-13 COSY methods, the proton and carbon-13 spectra are assigned completely. This also provides a basis for NMR characterization of the-similar new compounds.

Low temperature preparation and fuel cell properties of rare earth doped barium cerate solid electrolytes

The solid electrolytes, BaCe(0.8)Ln(0.2)O(2.9) (Ln: Gd, Sm, Eu), were prepared by the sol-gel method. XRD indicated that a pure orthorhombic phase was formed at 900 degrees C. The synthesis temperature by the sol-gel method was about 600 degrees C: lower than the high temperature solid phase reaction method. The electrical conductivity and impedance spectra were measured and the conduction mechanism was studied. The grain-boundary resistance of the solid electrolyte could be reduced or eliminated by the sol-gel method. The conductivity of BaCe0.8Gd0.2O2.9 is 7.87 x 10(-2) S.cm(-1) at 800 degrees C. The open-circuit voltage of hydrogen-oxygen fuel cell using BaCe0.8Gd0.2O2.9 as electrolyte was near to 1 V and its maximum power density was 30 mW.cm(-2).

Nuclear magnetic resonance spectral assignments of 2,2 '-bis(p-aminobenzoic ester)-1,1 '-binaphthyl

H-1 and C-13 nuclear magnetic resonance (NMR) spectra of 2, 2'-bis(p-aminobenzoic ester)-1,1'-binaphthyl were assigned and confirmed using 2D H-1-H-1 COSY, C-13-H-1 HETCOR and C-13-H-1 long-range HETCOR methods. This provided a basis for NMR characterization of the similar compounds.