Nanostructured elements are provided for use in the electrode of a membrane electrode assembly for use in fuel cells, sensors, electrochemical cells, and the like. The nanostructured elements comprise acicular microstructured support whiskers bearing acicular nanoscopic catalyst particles which may comprise alternating layers of catalyst materials, which may comprise a surface layer that differs in composition from the bulk composition of the catalyst particles, and which may demonstrate improved carbon monoxide tolerance.

Catalyst for membrane electrode assembly and method of making

Membrane electrode assemblies are described that include an ion conductive membrane a catalyst adjacent to the major surfaces of the ion conductive membrane and a porous particle filled polymer membrane adjacent to the ion conductive membrane. The catalyst can be disposed on the major surfaces of the ion conductive membrane. Preferably, the catalyst is disposed in nanostructures. The polymer film serving as the electrode backing layer preferably is processed by heating the particle loaded porous film to a temperature within about 20 degrees of the melting point of the polymer to decrease the Gurley value and the electrical resistivity. The MEAs can be produced in a continuous roll process. The MEAs can be used to produce fuel cells, electrolyzers and electrochemical reactors.

Membrane electrode assemblies

A membrane electrode assembly is provided comprising an ion conducting membrane and one or more electrode layers that comprise nanostructured elements, wherein the nanostructured elements are in incomplete contact with the ion conducting membrane. This invention also provides methods to make the membrane electrode assembly of the invention. The membrane electrode assembly of this invention is suitable for use in electrochemical devices, including proton exchange membrane fuel cells, electrolyzers, chlor-alkali separation membranes, and the like.

Membrane electrode assembly

Microtextured catalyst transfer substrate

Areas of particular current interest in the field of unimolecular reactions are reviewed. New developments and experimental applications of the theory of thermal unimolecular reactions are discussed, with particular stress on simple descriptions of both the low and high-pressure limiting ranges and the intermediate fall-off. Recent experimental studies of elementary steps in unimolecular reactions after optical (one photon) and molecular beam (chemical) activation are reviewed in relation to theory. The kinetic and mechanistic aspects of the new field of unimolecular reactions induced by monochromatic infrared radiation (URIMIR, with multiphoton excitation) are developed in some detail. Experiments in this area are summarized and their role for the interpretation of URIMIR is discussed.

Current Aspects of Unimolecular Reactions

Multiphoton dissociation of ppm level CTF3 in CHF3 is reported. The effect of buffer gas pressure on the specific dissociation rates and the isotopic selectivity is investigated. Pulse energy dependence of the dissociation rates is converted to the intrinsic relation between the fractional conversion per pulse and the fluence by means of the new deconvolution technique. By addition of 100 Torr argon, the critical fluence of CTF3 was decreased from 136 to 34 J/cm2, while the intrinsic selectivity was increased from 34 to 580. In the absence of buffer gas argon, the fractional conversion per pulse exhibits two different pressure dependences. Unlike in the case below 15 Torr, the system shows strong pressure dependence and loss of the isotopic selectivity above 15 Torr. Possible application to the tritium removal process is also discussed.

CO2 laser tritium isotope separation: Collisional effects in multiphoton dissociation of trifluoromethane

Tritium Separation by CO2 Laser Multiphoton Dissociation of Trifluoromethane

tritium isotope separation by CO2 laser-induced multiphoton dissociation of CTF3

The ν3 band of UF6 is studied at a low rotational and vibrational temperature using a tunable diode laser. Infrared absorption in a pulsed supersonic free jet of UF6 is observed by phase sensitive detection synchronized with the pulse frequency. Absorption lines from P(21) to R(27) are measured for 238UF6 with a Doppler limit resolution. Only Q-branch peaks are observed for 235UF6 using naturally abundant isotopic species. Isotope shift for the ν3 band is determined to be 0.6040 cm-1.

Cold Jet Infrared Absorption Spectroscopy: The ν 3 Band of UF 6

OF THE DISCLOSURE A catalyst for concentrating hydrogen isotopes for use in performing hydrogen isotopes exchange between gaseous hydrogen and liquid water, the catalyst comprising a support of porous polytetrafluoroethylene having a total specific surface area of 2 to 80 m2/g as a result of mixing therewith 0.5 to 15%by weight of fluorocarbon or a porous styrene polymer or styrene/divinylbenzene copolymer having a specific surface area of at least 150 m2/g, and deposited on the support particles of at least one element selected from Group VIII of the Periodic Table. A method for producing a support of porous polytetra-fluoroethylene for such catalyst is also disclosed.

Ryohei Nakane

Papers

CO2 laser tritium isotope separation: Collisional effects in multiphoton dissociation of trifluoromethane

Tritium Separation by CO2 Laser Multiphoton Dissociation of Trifluoromethane

tritium isotope separation by CO2 laser-induced multiphoton dissociation of CTF3

Cold Jet Infrared Absorption Spectroscopy: The ν 3 Band of UF 6

Catalyst for concentrating hydrogen isotopes and process for producing a support therefor