Abstract:
Die vorliegende Erfindung betrifft ein Verfahren zur elektrochemischen Abscheidung von nanoskaligen Katalysatorpartikeln unter Verwendung einer als Gegenelektrode für die Arbeitselektrode fungierenden Wasserstoffverzehranode, wobei eine gleichzeitige Entwicklung von Wasserstoff an der Arbeitselektrode weitgehend oder vollständig vermieden wird.
Abstract:
The invention relates to a method for producing amorphous and/or crystalline metal (mixed) oxides, especially metals of the third to fifth main group or subgroups of the periodic table, the mean particle diameters of the (mixed) oxides being between 1 and 500 nm, especially between 1 and 100 nm. The ions of the metal(s) from which the (mixed) oxide is to be produced and which are dissolved in an organic electrolyte are electrochemically reduced on a cathode in an electrolysis device fitted with a cathode and an anode, in the presence of an oxidation agent. The cathode space (cathode half-cell) and anode space (anode half-cell) are separated by a porous separating wall or barrier (diaphragm) which enables the passage of a flow, i.e. which is permeable to cations and anions, but renders difficult, especially prevents, the passage of elementary halogens from the anode space to the cathode space.
Abstract:
A method of producing a ultrahydrophobic substrate provided on its surface with metallic nanoparticles comprising the steps of furnishing a ultrahydrophobic substrate, applying a precursor layer on said substrate with deposition of metallic nanoparticles from the precursor layer on the substrate. The precursor layer is preferably free of electronic conductive particles and the particles are preferably deposited electrochemically from the precursor layer.
Abstract:
The invention relates to a method for the electrochemical deposition of catalyst nanoparticles using a hydrogen-consuming anode acting as a counter-electrode for the working electrode, wherein simultaneous evolution of hydrogen at the working electrode is largely or completely avoided.
Abstract:
The present invention describes a method and an apparatus for the electrochemical deposition of fine catalyst particles onto carbon fibre-containing substrates which have a compensating layer ("microlayer"). The method comprises the preparation of a precursor suspension containing ionomer, carbon black and metal ions. This suspension is applied to the substrate and then dried. The deposition of the catalyst particles onto the carbon fibre-containing substrate is effected by a pulsed electrochemical method in an aqueous electrolyte. The noble metal-containing catalyst particles produced by the method have particle sizes in the nanometer range. The catalyst-coated substrates are used for the production of electrodes, gas diffusion electrodes and membrane electrode units for electrochemical devices, such as fuel cells (membrane fuel cells, PEMFC, DMFC, etc.), electrolysers or electrochemical sensors.
Abstract:
Beschrieben wird ein Verfahren zur Herstellung amorpher und/oder kristalliner (Misch-)Oxide von Metallen, insbesondere Metallen der dritten bis fünften Hauptgruppe oder der Nebengruppen des Periodensystems, mit mittleren Teilchendurchmessern der (Misch-)Oxide im Bereich von 1 bis 500 nm, insbesondere 1 bis 100 nm, bei dem man in einer mit einer Kathode und einer Anode ausgestatteten Elektrolysevorrichtung in einem organischen Elektrolyten gelöste lonen desjenigen oder derjenigen Metalle, deren (Misch-)Oxid hergestellt werden soll, in Gegenwart eines Oxidationsmittels an der Kathode elektrochemisch reduziert, wobei Kathodenraum (Kathodenhalbzelle) und Anodenraum (Anodenhalbzelle) durch eine poröse Trenn- oder Scheidewand (Diaphragma) voneinander getrennt sind, die den Stromdurchgang ermöglicht, also durchlässig für Kationen und Anionen ist, jedoch den Durchtritt von elementarem Halogen vom Anoden-zum Katodenraum erschwert, insbesondere verhindert.
Abstract:
Described is a monolithic catalyst system (1) for the cleavage of water into hydrogen and oxygen with the aid of light, comprising a first photoactive material (50) capable by itself or together with one or more auxiliary catalysts when irradiated with light having a wavelength ≥ 420 nm of generating oxygen and protons from water, and a second photoactive material (60) capable by itself or together one or more auxiliary catalysts (92) when irradiated with light having a wavelength ≥ 420 nm of reducing protons in water to hydrogen, the first photoactive material (50) and second photoactive material (60) being in electrical contact via one or more electron-conducting materials (30, 20, 40, 60a) the sytem being in that characterized in that a load or an electric consumer is interposed in between at least one electron-conducting material. Likewise described is a method of generating oxygen, hydrogen and electricity from water using the catalyst system.
Abstract:
There is described an open cell porous structure the cells of which are optionally filled with an elastomeric or thermosetting plastic comprising a nanocrystalline metallic or nanocrystalline metal matrix composite coating wherein the nanocrystals have a crystallite size of from about 5 nm to about 150 nm. A process for preparing the coated open cell porous structures is also disclosed.