Abstract: A catalyst composition comprises a particulate support and catalyst nanoparticles on the particulate support. The catalyst nanoparticles comprise an alloy of platinum and palladium in an atomic ratio of from about 25:75 to about 75:25 and are present in a concentration of between about 3 and about 10 wt % weight percent of the catalyst composition. The catalyst composition has an X-ray diffraction pattern that is substantially free of the (311) diffraction peak assignable to PtxPd1-x, where 0.25?x?0.75.

Abstract: A catalyst composition comprises a particulate support and catalyst nanoparticles on the particulate support. The catalyst nanoparticles comprise an alloy of platinum and palladium in an atomic ratio of from about 25:75 to about 75:25 and are present in a concentration of between about 3 and about 10 wt % weight percent of the catalyst composition. The catalyst composition has an X-ray diffraction pattern that is substantially free of the (311) diffraction peak assignable to PtxPd1-x, where 0.25?x?0.75.

Abstract: Processes for forming catalyst particles utilizing a defoamer are described. Also described are processes for forming catalysts, where the processes comprise providing a correlation between defoamer concentration and catalyst particle morphology, and determining an amount of defoamer to include in a precursor composition to obtain the target morphology based on the correlation.

Abstract: The invention is directed to high surface area graphitized carbon and to processes for making high surface area graphitized carbon. The process includes steps of graphitizing and increasing the surface area of (in either order) a starting carbon material to form high surface area graphitized carbon. The step of increasing the surface area optionally comprises an oxidizing step (e.g., through steam etching) or template removal from composite particles. The invention is also directed to catalyst particles and electrodes employing catalyst particles that are formed from the high surface area graphitized carbon.

Abstract: Processes for forming catalyst particles utilizing a defoamer are described. Also described are processes for forming catalysts, where the processes comprise providing a correlation between defoamer concentration and catalyst particle morphology, and determining an amount of defoamer to include in a precursor composition to obtain the target morphology based on the correlation.

Abstract: A membrane electrode assembly comprises (a) a solid electrolyte polymer membrane; (b) an anode electrocatalyst layer disposed at one surface of the membrane and comprising a first electrocatalyst composition comprising carbon substrate particles and nanoparticles comprising an alloy of platinum and ruthenium disposed on the surface of the substrate particles; (c) a cathode electrocatalyst layer disposed at an opposite surface of the membrane, the cathode layer comprising a second electrocatalyst composition different from the first electrocatalyst composition and comprising carbon substrate particles and nanoparticles comprising platinum disposed on the surface of the substrate particles; and (d) gas diffusion layers disposed over each of the anode and cathode electrocatalyst layers.

Abstract: In a method of producing a particulate electrocatalyst composition, a precursor medium comprising at least a first metal precursor, a liquid vehicle, and a substrate precursor to substrate particles is atomized into precursor droplets. The droplets are then heated to a reaction temperature of not greater than 700° C. to form composite particles comprising said first metal at least partly in an oxide form dispersed on said substrate particles. The composite particles are then collected and are heated at a first treatment temperature no greater than 250° C. in the presence of a reducing atmosphere to at least partly convert said oxide form to the metal.

Abstract: Composite particles comprising inorganic nanoparticles disposed on a substrate particle and processes for making and using same. A flowing aerosol is generated that includes droplets of a precursor medium dispersed in a gas phase. The precursor medium contains a liquid vehicle and at least one precursor. At least a portion of the liquid vehicle is removed from the droplets of precursor medium under conditions effective to convert the precursor to the nanoparticles on the substrate and form the composite particles.