Novel anode catalyst for direct methanol fuel cells.

PtRu catalyst is a promising anodic catalyst for direct methanol fuel cells (DMFCs) but the slow reaction kinetics reduce the performance of DMFCs. Therefore, this study attempts to improve the performance of PtRu catalysts by adding nickel (Ni) and iron (Fe). Multiwalled carbon nanotubes (MWCNTs) are used to increase the active area of the catalyst and to improve the catalyst performance. Electrochemical analysis techniques, such as energy dispersive X-ray spectrometry (EDX), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and X-ray photoelectron spectroscopy (XPS), are used to characterize the kinetic parameters of the hybrid catalyst. Cyclic voltammetry (CV) is used to investigate the effects of adding Fe and Ni to the catalyst on the reaction kinetics. Additionally, chronoamperometry (CA) tests were conducted to study the long-term performance of the catalyst for catalyzing the methanol oxidation reaction (MOR). The binding energies of the reactants and products are compared to determine the kinetics and potential surface energy for methanol oxidation. The FESEM analysis results indicate that well-dispersed nanoscale (2-5 nm) PtRu particles are formed on the MWCNTs. Finally, PtRuFeNi/MWCNT improves the reaction kinetics of anode catalysts for DMFCs and obtains a mass current of 31 A g(-1) catalyst.

1,1-Dibenzyl-3-(3-chloro-benzo-yl)thio-urea.

In the title compound, C(22)H(19)ClN(2)OS, the thiono and carbonyl groups are trans positioned with respect to a partially double C-N bond. The amide group is twisted relative to the thio-urea fragment, forming a dihedral angle of 46.75 (11)°. In the crystal, inter-molecular N-H⋯S and C-H⋯O hydrogen bonds link the mol-ecules into a one-dimensional polymeric structure parallel to the c axis.

3-(3-Meth-oxy-benzo-yl)-1,1-diphenyl-thio-urea.

The thiono and carbonyl groups in the title compound, C(21)H(18)N(2)O(2)S, adopt an anti disposition with respect to the central C-N bond. The diphenyl-amine rings are twisted relative to each other by a dihedral angle of 82.55 (10)°. The 3-meth-oxy-benzoyl fragment is twisted relative to one of the diphenyl-amine rings, forming a dihedral angle of 74.04 (9)°. In the crystal, pairs of inter-molecular N-H⋯S hydrogen bonds link the mol-ecules into centrosymmetric dimers, forming columns parallel to the a axis.

Numerical analysis of flow distribution behavior in a proton exchange membrane fuel cell.

The flow distribution of a proton exchange membrane fuel cell within a manifold plays an important role on its performance. This study presents a numerical analysis of the flow distribution behavior within different manifold configurations. A two-dimensional model with 75 cells was employed to study the flow behavior. The variation in the stoichiometry and number of cells was also studied. Three different flow configurations were considered with different numbers of flow inlets and outlets. The flow characteristics, such as the pressure and velocity variations in the manifold and cells, were measured to determine the effects of the different flow configurations. The results indicated that the double inlet/outlet configuration had the best flow distribution when using 75 cells. Moreover, increasing the stoichiometry resulted in a better flow distribution to the cells in a stack.