Abstract:
The present invention is directed to a composition for use as a catalyst in, for example, a fuel cell, the composition comprising platinum and copper, wherein the concentration of platinum is greater than 50 atomic percent and less than about 80 atomic percent, and further wherein the composition has a particle size which is less than 35 angstroms. The present invention is further directed to various methods for preparing such a composition.
Abstract:
A fuel cell catalyst comprising platinum, chromium, and copper, nickel or a combination thereof. In one or more embodiments, the concentration of platinum is less than 50 atomic percent, and/or the concentration of chromium is less than 30 atomic percent, and/or the concentration of copper, nickel, or a combination thereof is at least 35 atomic percent.
Abstract:
Methods and apparatus are provided for the preparation of a substrate having an array of diverse materials, the materials being deposited at spatially addressable, predefined regions. In particular, potential masking systems are provided which generate spatially and temporally varying electric, magnetic and chemical potentials across a substrate. These varying potentials are used to deposit components of source materials onto a substrate in a combinatorial fashion, thus creating arrays of materials that differ slightly in chemical composition, concentration, stoichiometry, and/or thickness. The diverse materials may be organized in discrete arrays, or they may vary continuously over the surface of the substrate. The shape of the potential allows the determination of the composition of the resulting materials at all locations on the substrate.
Abstract:
A method for forming a supported metal-containing powder. The method comprises forming a dispersion of a particulate support in a solution, which comprises a solvent and a dissolved metal. Heat is removed from the dispersion to precipitate the dissolved metal from the solution onto the particulate support. Preferably, enough heat is removed to freeze the solution. The heat is preferably removed from the dispersion by contacting a container containing the dispersion with a cryogenic liquid, such as liquid nitrogen. After precipitating the dissolved metal onto the particulate support, the particulate support is separated from the solution, preferably by freeze-drying, to yield the supported metal-containing powder, which comprises the particulate support and a precipitated metal thereon.
Abstract:
An improved metal alloy fuel cell electrocatalyst composition containing comprising platinum, molybdenum, and a metal selected from the group consisting of nickel, iron, tin, and tungsten, provided (i) the concentration of each of nickel and iron is less than 70 atomic percent, and (ii) the concentration of nickel or iron is less than 20 atomic percent when the alloy contains both nickel and iron.
Abstract:
An improved metal alloy fuel cell electrocatalyst composition containing platinum, rhodium, molybdenum, and nickel, iron or a combination thereof.
Abstract:
An improved metal alloy fuel cell electrocatalyst composition containing platinum, rhodium, molybdenum, and nickel, iron or a combination thereof.
Abstract:
The present invention is directed to a composition for use as a catalyst in, for example, a fuel cell, the composition comprising platinum, nickel, and iron, wherein (i) the concentration of platinum is greater than 50 atomic percent, the concentration of nickel is less than 15 atomic percent and/or the concentration of iron is greater than 30 atomic percent, or (ii) the concentration of platinum is greater than 70 atomic percent and less than about 90 atomic percent. The present invention is further directed to a process for preparing such a catalyst composition from a catalyst precursor composition comprising platinum, nickel, and iron, wherein the concentration of platinum therein is less than 50 atomic percent.
Abstract:
A fuel cell catalyst comprising platinum, titanium and tungsten. In one or more embodiments, the concentration of platinum is less than 60 atomic percent, and/or the concentration of titanium is at least 20 atomic percent, and/or the concentration of tungsten is at least 25 atomic percent.