Development of new systems of nano-disperse Pt-(2%Pt-Ce0.9W0.1O2)/C electrocatalysts tolerant to carbon monoxide (CO) for PEMFC anodes

The nanophase material (powder) of Ce0.9W0.1O2 was synthesized via coprecipitation of oxalates of cerium (IV) and tungsten cations. Pt-Ce0.9W0.1O2 (2 wt% Pt) was prepared by an alcohol-reduction process using H2PtCl6.6H2O as source of Pt, Ce0.9W0.1O2 as support and ethylene glycol as solvent and reducing agent. Pt-Ce0.9W0.1O2 was physically mixed with commercial Pt/C E-TEK (20 w% Pt) to produce the Pt-(2%Pt-Ce0.9W0.1O2)/C electrocatalyst. The prepared electrocatalysts were characterized by energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and CO stripping. The performances of Pt/C E-TEK and Pt-(2%Pt-Ce0.9W0.1O2)/C electrocatalysts were tested in single fuel cell fed with a mixture H2/CO (100 ppm of CO). The results showed that the mixture of 2%Pt-Ce0.9W0.1O2 and Pt/C E-TEK increases the CO tolerance in a single fuel cell operating at 85 ºC compared with Pt/C E-TEK

CCDC 208055: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures

Structure-property relationships in radiation grafted poly(tetrafluoroethylene)-graft-polystyrene sulfonic acid membranes

Structure-property relationships in poly(tetrafluoroethylene)-graft-polystyrene sulfonic acid (PTFE-g-PSSA) membranes prepared by radiation-induced grafting of styrene onto poly(tetrafluoroethylene)(PTFE) films using simultaneous radiation-induced grafting followed by sulfonation reaction were established. The physico-chemical properties of the membranes such as ion exchange capacity, water uptake (swelling) and ionic conductivity were investigated in correlation with the degree of grafting (the amount sulfonated polystyrene grafted therein) and the structural changes taking place in the membrane matrix during the preparation step. The variation in the crystallinity of membranes was studied by differential scanning calorimetry (DSC). The membrane thermal stability was investigated using thermogravimetric analysis (TGA), ion exchange capacity and water uptake measurements. The membranes were found to undergo substantial structural changes in a form of ionic sites increase, hydrophicity enhancement, hydrophobicity reduction and crystallinity decrease with the increase in the degree of grafting. The all four factors were found to have a collective effect on the physico-chemical properties of the membranes but their relative contribution depends on the degree of grafting