Abstract: An electrode catalyst for a fuel cell includes a conductive support, and catalytic particles loaded on the conductive support. The catalytic particles include platinum and a base metal being on the lower end of the electrochemical series with respect to platinum. The number of the atoms of the base metal, forming metallic oxides without alloying with the platinum, is less than 5 atomic % of the number of the atoms of the platinum on a surface of the catalytic particles. The electrode catalyst is produced by loading the platinum and base metal on the conductive support, alloying the platinum and base metal thereon by a heat treatment, thereby making the catalytic particles, and removing metallic oxides from a surface of the catalytic particles. The electrode catalyst is less expensive comparatively, exhibits high catalytic activities, and hardly lowers the battery performance of fuel cells.

Abstract: In a powder-form electrode catalyzer for a fuel cell which comprises catalyst particles that contain platinum, and an electrically conductive support supporting the catalyst particles, the ratio between a mean value D111 of crystallite diameters of catalyst particles in a direction perpendicular to a (111) crystal face and a mean value D100 of crystallite diameters of the catalyst particles in a direction perpendicular to a (100) crystal face is D100/D111<1, and a mean crystallite diameter of the catalyst particles is at most 5 nm. Due to a large surface area that functions as a catalyst and a great proportion of the catalyst particles that have (100) crystal faces present on surfaces, the electrode catalyzer has high oxygen reduction activity.

Abstract: An electrode catalyst for a fuel cell includes a conductive support, and catalytic particles loaded on the conductive support. The catalytic particles include platinum and a base metal being on the lower end of the electrochemical series with respect to platinum. The number of the atoms of the base metal, forming metallic oxides without alloying with the platinum, is less than 5 atomic % of the number of the atoms of the platinum on a surface of the catalytic particles. The electrode catalyst is produced by loading the platinum and base metal on the conductive support, alloying the platinum and base metal thereon by a heat treatment, thereby making the catalytic particles, and removing metallic oxides from a surface of the catalytic particles. The electrode catalyst is less expensive comparatively, exhibits high catalytic activities, and hardly lowers the battery performance of fuel cells.

Abstract: A humidifier device for use in fuel cells comprising a mist humidifier unit for adding mists to process gas supplied to an electrolyte equipped in a fuel cell and a humidifier unit control device for intermittently operating the mist humidifier unit in accordance with operating condition of the fuel cell.

Abstract: Disclosed is a method of forming a nickel metal thin film, comprising the steps of coating a substrate with a solution for forming a nickel metal thin film, the solution being formed of an alcohol solution containing nickel ions and a reducible chelate type ligand having a hydrazone unit so as to form a gel film, and subjecting the resultant gel film to a heat treatment under an inert gas atmosphere.

Abstract: Disclosed is a method of forming a nickel metal thin film, comprising the steps of coating a substrate with a solution for forming a nickel metal thin film, the solution being formed of an alcohol solution containing nickel ions and a reducible chelate type ligand having a hydrazone unit so as to form a gel film, and subjecting the resultant gel film to a heat treatment under an inert gas atmosphere.

Abstract: Steam is contacted with a hydrogen absorbing alloy in a temperature range from 200.degree. C. to 400.degree. C. With a contact catalytic reaction of water, a metal contained in the hydrogen absorbing alloy is changed to an oxide or a hydroxide. Hydrogen produced causes the Ni compound to be reduced and thereby the Ni metal that is catalytically active is produced. Thus, the surface of the hydrogen absorbing alloy is activated. The steam is contained in an inert gas or a reductive gas. This treatment method is suitable as an activation treatment for a hydrogen absorbing alloy used as an active material of a negative electrode of a secondary battery.