Abstract: In a solid polymer fuel cell series, various circumstances can result in the fuel cell being driven into voltage reversal. For instance, cell voltage reversal can occur if that cell receives an inadequate supply of fuel (for example, fuel starvation). In order to pass current during fuel starvation, reactions other than fuel oxidation may take place at the fuel cell anode, including water electrolysis and oxidation of anode components. The latter may result in significant degradation of the anode. Such fuel cells can be made more tolerant to cell reversal by promoting water electrolysis over anode component oxidation at the anode. This can be accomplished by incorporating a catalyst composition at the anode to promote the water electrolysis reaction, in addition to the typical anode electrocatalyst for promoting fuel oxidation.

Abstract: The activity of catalysts used in promoting the oxidation of certain oxidizable species in fluids can be enhanced via electrochemical methods, e.g., NEMCA. In particular, the activity of catalysts used in the selective oxidation of carbon monoxide can be enhanced. A purification system that exploits this effect is useful in purifying reformate supplied as fuel to a solid polymer electrolyte fuel cell stack. The purification system comprises an electrolytic cell with fluid diffusion electrodes. The activity of catalyst incorporated in the cell anode is enhanced.

Abstract: A bonded structure including one or more substrates bonded together with a tackified amorphous poly-alpha-olefin adhesive composition. One method of making such a bonded structure is carried out by applying a tackified amorphous poly-alpha-olefin adhesive composition to one or more substrates at a temperature of about 170 degrees Celsius or lower, and joining the substrates to themselves or to one another. The bonded structure has a dynamic peel strength between about 400 and about 1000 grams per 25 millimeters. The bonding efficiency of the bonded structure renders the bonded structure suitable for incorporation into a variety of articles, including personal care products, health/medical products, and household/industrial product, for example.

Abstract: An adhesive composition including an atactic polymer, an isotactic polymer, and an extensible base polymer, such as ethylene-vinyl acetate and/or ethylene methacrylate. The composition may also include a tackifier, such as a high softening point tackifier resin, a low softening point additive, and/or other additives, such as an antioxidizing agent, a plasticizer, mineral oil, color pigment, filler, polymer compatibilizer, or a combination of any of these additives. Facing layers, particularly stretchable and/or elastomeric substrates, can be bonded with the adhesive composition. The adhesive composition maintains high bond strength, even at body temperature and after initial stretching. Such adhesive compositions and laminates can be made according to a method of the invention.

Abstract: Operation of an electrochemical fuel cell may lead to formation of oxide and/or hydroxide layers forming on the surface of a platinum catalyst on the cathode electrode which may, in turn, lead to reduced fuel cell performance. Such formation oxides and hydroxides may be inhibited or even eliminated by alloying the platinum catalyst with less than 10% of a noble metal selected from rhodium, iridium, palladium and gold or a combination thereof.

Abstract: Liquid cooled systems having coolant circulation loops must often operate in below freezing conditions. For instance, in various applications certain fuel cell systems must be able to tolerate repeated shutdown and storage in below freezing conditions. Conventional glycol-based coolants typically used for internal combustion engines are generally unsuitable for use in the associated fuel cell cooling subsystems due to the presence of additives and/or inhibitors which are normally included to deal with problems relating to decomposition of the glycol. With additives or inhibitors present, the coolant conductivity can be sufficiently high as to result in electrical shorting or corrosion problems. However, provided the purity of the coolant is maintained, a pure glycol and water coolant mixture may be used as a fuel cell system coolant to obtain suitable antifreeze protection. Adequate purity can be maintained by including an ion exchange resin unit in the cooling subsystem.

Abstract: In a solid polymer fuel cell series, various circumstances can result in a fuel cell being driven into voltage reversal. For instance, cell voltage reversal can occur if that cell receives an inadequate supply of fuel. In order to pass current, reactions other than fuel oxidation may take place at the fuel cell anode, including water electrolysis and oxidation of anode components. The latter may result in significant degradation of the anode, particularly if the anode employs a carbon black supported catalyst. Such fuel cells can be made more tolerant to cell reversal by using higher catalyst loading or coverage on the anode catalyst support or a more oxidation resistant anode catalyst support, such as a more graphitic carbon or Ti4O7.

Abstract: Non-noble metal transition metal catalysts can replace platinum in the oxidation reduction reaction (ORR) used in electrochemical fuel cells. A RuxSe catalyst is prepared with comparable catalytic activity to platinum. An environmentally friendly aqueous synthetic pathway to this catalyst is also presented. Using the same aqueous methodology, ORR catalysts can be prepared where Ru is replaced by Mo, Fe, Co, Cr, Ni and/or W. Similarly Se can be replaced by S.

Abstract: In an electrochemical fuel cell, a sufficient quantity of catalyst, effective for promoting the reaction of reactant supplied to an electrode, is disposed within the volume of the electrode so that a reactant introduced at a first major surface of the electrode is substantially completely reacted upon contacting the second major surface. Crossover of reactant from one electrode to the other electrode through the electrolyte in an electrochemical fuel cell is thereby reduced.

Abstract: A process for forming a hafnium oxide-containing film on a substrate such as silicon that includes introducing an anhydrous hafnium nitrate-containing precursor into a reactor containing the substrate, and converting the precursor into the hafnium oxide-containing film on the substrate by chemical vapor deposition.

Abstract: In a solid polymer fuel cell series, various circumstances can result in a fuel cell being driven into voltage reversal. For instance, cell voltage reversal can occur if that cell receives an inadequate supply of fuel. In order to pass current, reactions other than fuel oxidation can take place at the fuel cell anode, including water electrolysis and oxidation of anode components. The latter can result in significant degradation of the anode, particularly if the anode employs a carbon black supported catalyst. Such fuel cells can be made substantially more tolerant to cell reversal by using certain anodes employing both a higher catalyst loading or coverage on a corrosion-resistant support and by incorporating, in addition to the typical electrocatalyst for promoting fuel oxidation, certain unsupported catalyst compositions to promote the water electrolysis reaction.

Abstract: A method of detecting transfer leaks within a solid polymer electrolyte fuel cell stack comprising a plurality of fuel cell assemblies includes supplying reactants and inert gas to the fuel, oxidant and/or coolant manifolds of the stack, as appropriate, and measuring the voltage across at least one of the fuel cell assemblies. An apparatus for detecting transfer leaks within solid polymer electrolyte fuel cell stacks comprises a device for measuring the voltage across at least one of the fuel cell assemblies. Transfer leaks across the polymer electrolyte membrane, and across reactant-coolant bipolar plates, may be detected according to the present method and apparatus.

Abstract: Axial flow dehydrogenation reactors comprising multiple catalyst beds formed of honeycomb monoliths, the beds being separated from each other by heating stages to maintain reactant stream temperature, provide low pressure drop and improved conversion efficiency when used alone or in combination with other reactors, e.g., as reactor upgrades for series reactor systems incorporating radial flow reactor stages.

Abstract: In an electrochemical fuel cell, a sufficient quantity of catalyst, effective for promoting the reaction of reactant supplied to an electrode, is disposed within the volume of the electrode so that a reactant introduced at a first major surface of the electrode is substantially completely reacted upon contacting the second major surface. Crossover of reactant from one electrode to the other electrode through the electrolyte in an electrochemical fuel cell is thereby reduced.

Abstract: A method is provided for treating electrocatalyst particles and using the treated electrocatalyst for improving performance in an electrochemical fuel cell. The treatment method comprises impregnating pores of the electrocatalyst particles with an impregnant wherein the pores comprise micropores which have an aperture size less than 0.1 micron. The impregnant is preferably ion-conducting and may comprise an organic acid, an inorganic acid, or a polymer. Alternatively, or in addition, the impregnant has an oxygen permeability greater than that of water. The method of impregnating the electrocatalyst particles preferably comprises the steps of contacting the electrocatalyst particles with an impregnant and subjecting the electrocatalyst particles to a vacuum and/or an elevated pressure above atmospheric pressure. The treated electrocatalyst particles are incorporated into an electrochemical fuel cell.

Abstract: A process for forming a hafnium oxide-containing film on a substrate such as silicon that includes introducing an anhydrous hafnium nitrate-containing precursor into a reactor containing the substrate, and converting the precursor into the hafnium oxide-containing film on the substrate by chemical vapor deposition.

Abstract: A device for distributing fluid into a monolith bed includes a plurality of flow channels stacked in order of decreasing diameter. The flow channels successively split a flow stream into a multiple flow streams prior to the flow stream entering the monolith bed.

Abstract: Carbon-supported catalysts are frequently employed in the electrodes of solid polymer fuel cells in order to make efficient use of the catalyst therein. The catalyst utilization in the electrode and the fuel cell performance can be further improved by introducing acidic surface oxide groups on the carbon-supported catalyst. The introduction of acidic surface oxide groups on the carbon-supported catalyst can be accomplished by treating the carbon-supported catalyst with a suitable acid, such as nitric acid, before incorporating the carbon-supported catalyst in a fuel cell electrode. The present technique is particularly suitable for use in solid polymer fuel cell cathodes.

Abstract: The activity of catalysts used in promoting the oxidation of certain oxidizable species in fluids can be enhanced via electrochemical methods, e.g., NEMCA. In particular, the activity of catalysts used in the selective oxidation of carbon monoxide can be enhanced. A purification system that exploits this effect is useful in purifying reformate supplied as fuel to a solid polymer electrolyte fuel cell stack. The purification system comprises an electrolytic cell with fluid diffusion electrodes. The activity of catalyst incorporated in the cell anode is enhanced.

Abstract: A fuel cell fluid distribution layer, in one embodiment, comprises perforated graphite foil. The fluid distribution layer can have one or more reactant flow field channels formed in one or both major surfaces, one or more manifold openings, conductive filler on one or both major surfaces, conductive filler at least partially filling some or all perforations and/or an electrocatalyst one or both major surfaces.