Abstract: The present invention provides a supported metal catalyst that has an electric conductivity acceptable as a catalyst and can suppress the generation of hydrogen peroxide. According to the present invention, provided is a supported metal catalyst, comprising: a support powder; and metal fine particles supported on the support powder, wherein: the support powder is an aggregate of support fine particles; the support fine particles have a chained portion structured by a plurality of crystallites being fusion-bonded to form a chain; the support fine particles are structured with a metal oxide; the metal oxide contains cerium; and an electric conductivity of the supported metal catalyst is 10?4 S/cm or higher.

Abstract: A bead string of tin oxide crystallite or a bead string of complex oxide crystallite of tin oxide and titanium oxide contains tantalum and has specific hue as well as a crystallite size on the order of nanometer, and exhibits excellent conductivity and improves the catalytic activity. A bead string includes a tin oxide crystal particle aggregate or a crystal particle aggregate of a complex oxide of tin oxide and titanium oxide, in which the crystal particle aggregate contains at least one particle having a crystallite size of 5 to 50 nm, and when the crystal particle aggregate is pressed under a pressure of 0.1 MPa to have a thickness of 1 cm, in the color of the resultant particle aggregate represented by Lab color space, a lightness L* value is 80 or less, a chromaticity a* value is ?4 or less, and a chromaticity b* is ?3 or less.

Abstract: A supported metal catalyst in which an electric conductivity is enhanced. The supported metal catalyst includes a support powder; and metal fine particles supported by the support powder. The support powder is an aggregate of support fine particles; the support fine particles are provided with a chained portion structured by a plurality of crystallites being fusion-bonded to form a chain; the support fine particles are structured with a metal oxide; and the supported amount of metal fine particles per unit area of the surface area of the support powder calculated based on sphere approximation is 3.4 to 13.7 (mg/m2).

Abstract: An electrode catalyst including a void-containing body having a void, the void-containing body includes a core part and a skin layer covering the core part, the core part is structured with metal, and the skin layer is structured with an oxide containing Ni.

Abstract: A support powder can improve cell performance under high humidity environment. A support and metal catalyst, including: a support powder; and metal fine particles supported on the support powder; wherein: the support powder is an aggregate of support fine particles; the support fine particles are fine particles of oxide compound and has a chained portion structured by a plurality of crystallites being fusion bonded to form a chain; the crystallites have a size of 10 to 30 nm; the support powder has a void; the void includes a secondary pore having a pore diameter of more than 25 nm and 80 nm or less determined by BJH method; and a volume of the secondary pore per unit volume of the support fine particles structuring the support powder is 0.313 cm3/cm3 or more, is provided.

Abstract: A membrane-electrode assembly including a catalyst layer that includes a catalyst-supporting carrier in which a catalyst is supported on a carrier made of an inorganic oxide, and a highly hydrophobic substance having a higher degree of hydrophobicity than the inorganic oxide, the catalyst layer being formed on at least one surface of a polymer electrolyte membrane. It is preferable that, in the membrane-electrode assembly, the degree of hydrophobicity of the highly hydrophobic substance is from 0.5 vol % to 45 vol % at 25° C., the degree of hydrophobicity being defined as a concentration of methanol (vol %) when a light transmittance of a dispersion obtained by dispersing the highly hydrophobic substance in a mixed solution of water and methanol reaches 80%.

Abstract: The carrier metal catalyst achieves suppression of internal resistance of a fuel cell. A carrier metal catalyst includes: a carrier powder; and metal fine particles supported on the carrier powder; wherein: the carrier powder is an aggregates of carrier fine particles; the carrier fine particles includes a chained portion structured by a plurality of crystallites being fusion bonded to form a chain; the carrier fine particles include titanium oxide; the carrier fine particles are doped with an element having a valence different from a valence of titanium; the titanium oxide of the carrier powder has an anatase phase/rutile phase ratio of 0.2 or lower; the metal fine particles have a mean particle size of 3 to 10 nm; the metal fine particles include platinum; and a cell resistance measured under standard conditions of a fuel cell prepared using the carrier metal catalyst is 0.090 ?cm·2 or lower.

Abstract: A carrier powder is thermodynamically stable and conductivity can be easily provided thereto. A carrier powder includes an aggregate of carrier fine particles; wherein: the carrier fine particles include a chained portion structured by fusion bonding a plurality of crystallites into a chain; the carrier fine particles contain titanium oxide; and a ratio of anatase phase/rutile phase of the titanium oxide of the carrier powder is 0.2 or lower.

Abstract: A support and metal catalyst with improved electric conductivity is provided. A support and metal catalyst, including: a support powder; and metal fine particles supported on the support powder; wherein: the support powder is an aggregate of support fine particles; the support fine particles have a chained portion structured by a plurality of crystallites being fusion bonded to form a chain; the support fine particles are structured with metal oxide; and the metal oxide is doped with a dopant element, and an atomic ratio of titanium with respect to total of titanium and tin is 0.30 to 0.80, is provided.

Abstract: The carrier metal catalyst achieves suppression of internal resistance of a fuel cell. A carrier metal catalyst includes: a carrier powder; and metal fine particles supported on the carrier powder; wherein: the carrier powder is an aggregates of carrier fine particles; the carrier fine particles includes a chained portion structured by a plurality of crystallites being fusion bonded to form a chain; the carrier fine particles include titanium oxide; the carrier fine particles are doped with an element having a valence different from a valence of titanium; the titanium oxide of the carrier powder has an anatase phase/rutile phase ratio of 0.2 or lower; the metal fine particles have a mean particle size of 3 to 10 nm; the metal fine particles include platinum; and a cell resistance measured under standard conditions of a fuel cell prepared using the carrier metal catalyst is 0.090 ?·cm2 or lower.

Abstract: An electrode catalyst support, capable of improving the power of a fuel cell, and an electrode catalyst and a solid polymer fuel cell using the same. Provided is carbon black wherein pores which are at most 6 nm in pore diameter have a cumulative pore volume of less than 0.25 cm3/g, a specific surface area by BET is 500 to 900 m2/g, and a volatile matter content is 1.0 to 10.0%. Also provided are an electrode catalyst for a fuel cell comprising a support which includes this carbon black, and a solid polymer fuel cell having the electrode catalyst.

Abstract: A support powder can improve cell performance under high humidity environment. A support and metal catalyst, including: a support powder; and metal fine particles supported on the support powder; wherein: the support powder is an aggregate of support fine particles; the support fine particles are fine particles of oxide compound and has a chained portion structured by a plurality of crystallites being fusion bonded to form a chain; the crystallites have a size of 10 to 30 nm; the support powder has a void; the void includes a secondary pore having a pore diameter of more than 25 nm and 80 nm or less determined by BJH method; and a volume of the secondary pore per unit volume of the support fine particles structuring the support powder is 0.313 cm3/cm3 or more, is provided.

Abstract: A method for forming an electrode catalyst layer by putting catalyst ink within an insulative container having a conductive nozzle in communication with the interior of the container and applying an electrospray voltage to the nozzle to cause electrospray of the catalyst ink through the tip end of the nozzle and thereby to form an electrode catalyst layer, the method includes preparing catalyst ink containing a mixture of at least electrode catalyst, polymer electrolyte binder and volatile organic compound and/or water, putting the catalyst ink within the container with a space remaining inside thereof and air-tightly sealing the container, and electrospraying with the space inside of the air-tightly sealed container being conditioned to have a negative pressure of a level at which the catalyst ink cannot drip off from the nozzle.

Abstract: The carrier metal catalyst achieves suppression of internal resistance of a fuel cell. A carrier metal catalyst includes: a carrier powder; and metal fine particles supported on the carrier powder; wherein: the carrier powder is an aggregates of carrier fine particles; the carrier fine particles includes a chained portion structured by a plurality of crystallites being fusion bonded to form a chain; the carrier fine particles include titanium oxide; the carrier fine particles are doped with an element having a valence different from a valence of titanium; the titanium oxide of the carrier powder has an anatase phase/rutile phase ratio of 0.2 or lower; the metal fine particles have a mean particle size of 3 to 10 nm; the metal fine particles include platinum; and a cell resistance measured under standard conditions of a fuel cell prepared using the carrier metal catalyst is 0.090 ?·cm2 or lower.

Abstract: A carrier powder is thermodynamically stable and conductivity can be easily provided thereto. A carrier powder includes an aggregate of carrier fine particles; wherein: the carrier fine particles include a chained portion structured by fusion bonding a plurality of crystallites into a chain; the carrier fine particles contain titanium oxide; and a ratio of anatase phase/rutile phase of the titanium oxide of the carrier powder is 0.2 or lower.

Abstract: To spread the use of catalysts for fuel cells, there is a demand to develop a catalyst that uses less Pt and has a high power generation efficiency. An electrode catalyst includes a support particle containing a metal oxide and a precious-metal alloy supported on the support particle. The support particle includes multiple branches, a hole between the branches, and a pore. The pore is surrounded by the branches and the hole. The precious-metal alloy includes a precious metal element and at least one or more transition elements.

Abstract: A method for forming an electrode catalyst layer by putting catalyst ink within an insulative container having a conductive nozzle in communication with the interior of the container and applying an electrospray voltage to the nozzle to cause electrospray of the catalyst ink through the tip end of the nozzle and thereby to form an electrode catalyst layer, the method includes preparing catalyst ink containing a mixture of at least electrode catalyst, polymer electrolyte binder and volatile organic compound and/or water, putting the catalyst ink within the container with a space remaining inside thereof and air-tightly sealing the container, and electrospraying with the space inside of the air-tightly sealed container being conditioned to have a negative pressure of a level at which the catalyst ink cannot drip off from the nozzle.

Abstract: A membrane-electrode assembly including a catalyst layer that includes a catalyst-supporting carrier in which a catalyst is supported on a carrier made of an inorganic oxide, and a highly hydrophobic substance having a higher degree of hydrophobicity than the inorganic oxide, the catalyst layer being formed on at least one surface of a polymer electrolyte membrane. It is preferable that, in the membrane-electrode assembly, the degree of hydrophobicity of the highly hydrophobic substance is from 0.5 vol % to 45 vol % at 25° C., the degree of hydrophobicity being defined as a concentration of methanol (vol %) when a light transmittance of a dispersion obtained by dispersing the highly hydrophobic substance in a mixed solution of water and methanol reaches 80%.

Abstract: A membrane-electrode assembly including a catalyst layer that includes a catalyst-supporting carrier in which a catalyst is supported on a carrier made of an inorganic oxide, and a highly hydrophobic substance having a higher degree of hydrophobicity than the inorganic oxide, the catalyst layer being formed on at least one surface of a polymer electrolyte membrane. It is preferable that, in the membrane-electrode assembly, the degree of hydrophobicity of the highly hydrophobic substance is from 0.5 vol % to 45 vol % at 25° C., the degree of hydrophobicity being defined as a concentration of methanol (vol %) when a light transmittance of a dispersion obtained by dispersing the highly hydrophobic substance in a mixed solution of water and methanol reaches 80%.

Abstract: A fuel cell system and a method of operating the same is provided that is capable of reducing degradation of a cathode catalyst of a fuel cell. A fuel cell system is provided that includes a fuel cell having a catalyst used for an anode, wherein a carrier of the catalyst is composed of a material with a property where electric resistance in an oxygen containing atmosphere is greater than electric resistance in a hydrogen atmosphere; and a control device configured to control the fuel cell, when supply of fuel gas is stopped during stoppage of operation of the fuel cell, to consume all or part of the fuel gas in a fuel gas chamber, followed by introducing oxygen containing gas into the fuel gas chamber.