摘要:
Platinum particles have been formed as porous, hollow tubular dendrites by using silver dendrite particles in a galvanic replacement reaction conducted in an aqueous solution of a platinum compound. The dendritic platinum particles have been found useful as catalysts and particularly useful as a hydrogen-oxidation electrocatalyst and/or an oxygen-reduction catalyst in a polymer electrolyte membrane fuel cell.
摘要:
Spherical particles of one or more elemental metals and carbon are prepared from a precursor in the form of a metal oleate. The metal oleate precursor is dispersed in a liquid vehicle and aerosol droplets of the dispersed precursor are formed in a stream of an inert gas. The aerosol droplets are heated in the stream to decompose the oleate ligand portion of the precursor and form spherical particles that have a mesoporous nanocrystalline structure. The open mesopores of the spherical particles provide a high surface area for contact with fluids in many applications. For example, the mesopores can be infiltrated with a hydrogen absorbing material, such as magnesium hydride, in order to increase the hydrogen storage capacity of the particles.
摘要:
A high surface area support material is formed of an intimate mixture of carbon clusters and titanium oxide clusters. A catalytic metal, such as platinum, is deposited on the support particles and the catalyzed material used as an electrocatalyst in an electrochemical cell such as a PEM fuel cell. The composite material is prepared by thermal decomposition and oxidation of an intimate mixture of a precursor carbon polymer, a titanium alkoxide and a surfactant that serves as a molecular template for the mixed precursors.
摘要:
An electrocatalyst including an active catalyst component and an additive including a transitional metal, transitional metal oxide or complex precursor thereof, products including such an electrocatalyst and methods of making and using the same.
摘要:
Rare earth element(s) doped alumina nanowires are formed by a thermal evaporation method in which vapor from aluminum powder and vapor from a rare earth element compound (such as an halide) are reacted in an oxygen-containing inert gas stream to form alumina which deposits as alumina nanowires and as a rare earth element and oxygen-containing material that deposits with and/or on the alumina nanowires. Where the RE-doped alumina nanowires are to be used as catalyst supports, a catalyst material, such as platinum, may be deposited as small particles on the nanowires.
摘要:
A catalyst support material comprising TiO2, and optionally being doped with a transition metal element, and a method for synthesizing the same have been developed. The catalyst support material exhibits an electrical conductivity comparable to widely-used carbon materials. This is because the TiO2 present is primarily arranged in its rutile crystalline phase. Furthermore, a mesoporous morphology provides the catalyst support material with appropriate porosity and surface area properties such that it may be utilized as part of a fuel cell electrode (anode and/or cathode). The TiO2-based catalyst support material may be formed using a template method in which precursor titanium and transition metal alkoxides are hydrolyzed onto the surface of a latex template, dried, and heat treated.
摘要翻译:已经开发了包含TiO 2和任选地掺杂有过渡金属元素的催化剂载体材料及其合成方法。 催化剂载体材料表现出与广泛使用的碳材料相当的导电性。 这是因为存在的TiO 2主要排列在其金红石结晶相中。 此外,介孔形态为催化剂载体材料提供了适当的孔隙率和表面积性质,使得其可以用作燃料电池电极(阳极和/或阴极)的一部分。 TiO 2类催化剂载体材料可以使用其中前体钛和过渡金属醇盐水解到胶乳模板的表面上,干燥和热处理的模板方法形成。
摘要:
Glycerol is used as a solvent medium for the precipitation of a complex of nickel and glycerol material. The precipitate is separated from the liquid solvent and dried and calcined in air to produce small (nanometer size) particles characterized by a nickel core encased in a nickel oxide shell. The proportions of nickel core and nickel oxide shell can be controlled by management of the time and temperature of heating in air. Prolonged heating in air can produce nickel oxide particles, or calcining of the precipitate in nitrogen produces nickel particles.
摘要:
Metal powder (such as tin, titanium, or tungsten powder) is heated in a flowing stream of an inert gas, such as argon, containing a small abundance of oxygen at a temperature to produce metal vapor. The metal reacts with the oxygen to form and deposit one-dimensional nanostructures of oxygen-containing metal on the metal powder (in the case of Ti and W) or on a suitable nearby substrate in the case of the lower melting tin. The metal oxides are not necessarily stoichiometric compounds. Water may be introduced into the flowing inert gas to increase or control the oxygen content. Sulfur vapor or a carbon source may be introduced to dope the nanostructures with sulfur or carbon. Reaction conditions may be modified to vary the shapes of the one-dimensional nanostructures.
摘要:
An oxygen reducing electrode for a fuel cell comprises carbon particles as support for catalyst particles. The carbon particles are coated with smaller particles of a metal oxide and/or metal phosphate (for example, TiO2 particles) to impede destructive oxidation (corrosion) of the carbon particles while permitting suitable electrical conductivity between the carbon particles. The catalyst is carried on the smaller particle-coated carbon particles. Titanium dioxide particles can be dispersed on carbon particles suspended in a liquid medium by ultrasonic decomposition of a suitable titanium precursor compound.
摘要:
A method for controlling temperature of a catalytic converter in an automobile exhaust system is disclosed. The method includes establishing a reference temperature for the catalytic converter, distributing a stream of exhaust gases through the catalytic converter, obtaining a measured temperature of the catalytic converter and converting thermal energy from the stream of exhaust gases into electrical energy when the measured temperature exceeds the reference temperature. An apparatus for controlling temperature of a catalytic converter in an automobile exhaust system is also disclosed.