Abstract: The invention relates to novel nanoparticles comprising a metal core containing at least one platinoid or an alloy of a platinoid, a first organic coating formed from molecules attached to the surface of the metal core, and a second organic coating formed from molecules different from the molecules forming the first organic coating, and which are grafted onto molecules of the first organic coating. The invention also relates to the use of the nanoparticles as catalysts. The fields of application include devices for producing electrical energy, in particular in fuel cells, devices for detecting or assaying one or more chemical or biological species, in particular in sensors or multisensors, etc.

Abstract: The invention relates to the use of nanoparticles comprising a metal core containing at least one platinoid or an alloy of a platinoid, a first organic coating formed from molecules attached to the surface of the metal core and a second organic coating formed from molecules different from the molecules forming the first organic coating, and which are grafted onto molecules of the first organic coating, as catalysts. The invention also relates to novel nanoparticles that are useful as catalysts. The fields of application: devices for producing electrical energy, in particular in fuel cells, devices for detecting or assaying one or more chemical or biological species, in particular in sensors or multisensors, etc.

Abstract: Method for deoxidizing and passivating, by sulphidation, a surface of a III-V compound semiconductor material undergo strong oxidation in the presence of oxygen, wherein the surface to be passivated is immersed in a dilute aqueous solution containing sulphide ions with a concentration of between about 10−1M and 10−7M.

Abstract: Method for deoxidizing and passivating, by sulfidation, a surface of a III-V compound semiconductor material undergo strong oxidation in the presence of oxygen, wherein the surface to be passivated is immersed in a dilute aqueous solution containing sulfide ions with a concentration of between about 10−1M and 10−7M.

Abstract: Electrochemical generators comprising an anode consisting of a highly reducing metal or metallic alloy, such as an alkali metal or alkaline earth metal, a cathode consisting of a reducible material such as CuO, MnO.sub.2, AgO, and (SN).sub.x and a water-free liquid or solid electrolyte consisting of an ammoniate of a salt of a cation of the anode metal or of a more highly reducing metal, the salt being for example a halide or perhalogenate.