Abstract: A method for producing an electrode catalyst, comprising a step of calcining a precursor of the electrode catalyst under conditions under which a second material defined below can change into a carbonaceous material, the precursor having been obtained by continuously hydrothermally reacting a mixture containing a first material defined below and the second material defined below in the presence of supercritical or subcritical water, wherein the first material is defined to be a metal compound composed of one or more metal elements selected from the group consisting of the elements of Group 4A and the elements of Group 5A group and one or more non-metal elements selected from the group consisting of hydrogen, nitrogen, chlorine, carbon, boron, sulfur, and oxygen, and the second material is defined to be a precursor of a carbonaceous material.

Abstract: The invention provides catalysts that are not corroded in acidic electrolytes or at high potential and have excellent durability and high oxygen reducing ability. The catalyst includes a metal element M, carbon, nitrogen and oxygen, wherein the catalyst shows peaks at 1340 cm?1 to 1365 cm?1 and at 1580 cm?1 to 1610 cm?1 as analyzed by Raman spectroscopy and the metal element M is one selected from titanium, iron, niobium, zirconium and tantalum. The catalysts of the invention are stable and are not corroded in acidic electrolytes or at high potential, have high oxygen reducing ability and are inexpensive compared to platinum. Fuel cells having the catalysts are therefore relatively inexpensive and have high performance.

Abstract: [Problem] To provide a catalyst which has high oxygen reduction activity, also has excellent durability, and is inexpensive and excellent in electric power generation cost as compared with noble metal catalysts such as platinum. [Solution to problem] A catalyst for a polymer electrolyte fuel cell, including a graphitized carbon powder and a niobium oxycarbonitride or a titanium oxycarbonitride as an active substance, and a polymer electrolyte fuel cell using the catalyst.

Abstract: The invention provides catalysts that are not corroded in acidic electrolytes or at high potential and have excellent durability and high oxygen reducing ability, and processes for producing the catalysts and uses of the catalysts. The catalyst of the invention includes a metal oxycarbonitride that contains at least one metal selected from tantalum, vanadium, molybdenum and zirconium (hereinafter, also referred to as “metal M” or simply “M”) and does not contain any of platinum, titanium and niobium.

Abstract: [Object] The invention provides catalysts that are not corroded in acidic electrolytes or at high potential and have excellent durability and high oxygen reducing ability. [Solution] A catalyst of the invention includes a metal oxycarbonitride that contains titanium and at least one metal (hereinafter, also referred to as “metal M” or simply “M”) selected from silver, calcium, strontium, yttrium, ruthenium, lanthanum, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium.

Abstract: A corrosion-resistant electrode catalyst for oxygen reduction includes a main catalyst composed of at least one transition metal oxide selected from oxygen-deficient ZrO2, Ta2O5, Nb2O5, TiO2, V2O5, MoO3, and WO3 and a co-catalyst composed of gold. The electrode catalyst is used in contact with an acidic electrolyte at a potential at least 0.4 V higher than the reversible hydrogen electrode potential. The catalyst may be used, for example, in such a form that the transition metal oxide in the form of fine particles and gold in the form of fine particles, or fine particles including fine gold particles coated with the transition metal oxide are dispersed on a catalyst carrier which is an electron conductive powder. This electrode catalyst is suitable as an electrode catalyst for an electrochemical system using an acidic electrolyte in the fields of water electrolysis, inorganic/organic electrolysis, fuel cells, etc.

Abstract: An electrode catalyst that maintains catalytic activity under conditions of an electrode potential as high as 0.4 V or above and exhibits improved stability. The metal oxynitride electrode catalyst is composed of an oxynitride containing at least one transition metal element selected from the group consisting of La, Ta, Nb, Ti, and Zr, the metal oxynitride electrode catalyst being used at a potential of 0.4 V or higher relative to the reversible hydrogen electrode potential in an acidic electrolyte. The metal oxynitride electrode catalyst is useful as an electrode catalyst for electrochemical systems used in acidic electrolytes in the fields of water electrolysis, organic electrolysis, fuel cells, etc.

Abstract: A corrosion-resistant electrode catalyst for oxygen reduction includes a main catalyst composed of at least one transition metal oxide selected from oxygen-deficient ZrO2, Ta2O5, Nb2O5, TiO2, V2O5, MoO3, and WO3 and a co-catalyst composed of gold. The electrode catalyst is used in contact with an acidic electrolyte at a potential at least 0.4 V higher than the reversible hydrogen electrode potential. The catalyst may be used, for example, in such a form that the transition metal oxide in the form of fine particles and gold in the form of fine particles, or fine particles including fine gold particles coated with the transition metal oxide are dispersed on a catalyst carrier which is an electron conductive powder. This electrode catalyst is suitable as an electrode catalyst for an electrochemical system using an acidic electrolyte in the fields of water electrolysis, inorganic/organic electrolysis, fuel cells, etc.

Abstract: [Problems] Carbides and many other non-platinum-based compounds are activated and dissolved and cannot be stably present in an acidic electrolyte under conditions of an electrode potential as high as 0.4 V or above, and thus, the application range of these compounds as an electrode catalyst is limited to low electrode potentials. There has been need for development of an electrode catalyst that maintains catalytic activity under these conditions and exhibits improved stability. [Means for Solving Problems] To provide a metal oxynitride electrode catalyst composed of an oxynitride containing at least one transition metal element selected from the group consisting of La, Ta, Nb, Ti, and Zr, the metal oxynitride electrode catalyst being used at a potential of 0.4 V or higher relative to the reversible hydrogen electrode potential in an acidic electrolyte.