Abstract: A methanol oxidation catalyst comprises a material of composition: PtxMzTau in which Pt is platinum, Ta is tantalum, M is an element includes at least one selected from the group consisting of V (vanadium), W (tungsten), Ni (nickel) and Mo (molybdenum), x is 40 to 98 at. %, z is 1.5 to 55 at. %, and u is 0.5 to 40 at. %. To maximize catalytic activity the material is preferably in the form of nanoparticles. The values of x, z and u are selected such that the element exhibits X-ray photoelectron spectroscopy peaks derived from an oxygen bond and a metal bond in which a peak area derived from the oxygen bond is twice or less of a peak area derived from the metal bond.

Abstract: A catalyst is provided and includes fine catalyst particles of a composition represented by formula (1): PtuRuxTayTz, in which T is at least one element selected from the group consisting of Hf, W, Ni, and V; u, x, y, and z are 10 to 98.9 atm %, 0.1 to 50 atm %, 0.5 to 35 atm %, and 0.5 to 35 atm %, respectively, or formula (2): PtuRuxTayTz, in which T is at least one element selected from the group consisting of Ct, Mo, Nb, Zr, and T; u, x, y, and z are 40 to 70 atm %, 0.1 to 50 atm %, 0.5 to 15 atm %, and 0.5 to 15 atm %, respectively.

Abstract: There is provided a catalyst for a fuel cell, which simultaneously realizes excellent catalytic activity and catalytic stability. The catalyst for a fuel cell comprises a fine particle of a metal represented by formula: PtxRuySizT1u wherein T1 represents at least one element selected from the group consisting of nickel (Ni), tungsten (W), vanadium (V), and molybdenum (Mo); x=30 to 90 atomic %; y=0 to 50 atomic %; z=0.5 to 20 atomic %; and u=0.5 to 40 atomic %, or comprises a fine particle of a metal represented by formula: PtxRuySizT2u wherein T2 represents at least one element selected from the group consisting of hafnium (Hf), tin (Sn), zirconium (Zr), niobium (Nb), titanium (Ti), tantalum (Ta), chromium (Cr), and aluminum (Al); x=30 to 90 atomic %; y=0 to 50 atomic %; z=0.5 to 20 atomic %; and u=0.5 to 40 atomic %.

Abstract: This invention provides a process for producing a membrane electrode assembly which has high and stable catalytic activity, and suppressed deterioration in catalytic activity during operation, and can prevent a deterioration in performance attributable to a structural factor of the membrane electrode assembly. The process comprises the step of, after the washing/removing step, drying the catalyst electrode in an atmosphere having a lower oxygen partial pressure than the air. The anode/cathode is a covered catalyst electrode having a structure formed by supporting/depositing a catalytically active material composed mainly of platinum/ruthenium subjected to the potential holding step, the washing/removing step, and the drying step, on a porous electroconductive carrier to cover at least a part of the porous electroconductive carrier with the ion conductive material.

Abstract: A methanol oxidation catalyst is provided, which includes nanoparticles having a composition represented by the following formula 1: PtxRuyTzQu ??formula 1 In the formula 1, the T-element is at least one selected from a group consisting of Mo, W and V and the Q-element is at least one selected from a group consisting of Nb, Cr, Zr and Ti, x is 40 to 90 at. %, y is 0 to 9.9 at. %, z is 3 to 70 at. % and u is 0.5 to 40 at. %. The area of the peak derived from oxygen bond of T-element is 80% or less of the area of the peak derived from metal bond of T-element in a spectrum measured by an X-ray photoelectron spectral method.

Abstract: The present invention provides a catalyst having high activity and excellent stability, a process for preparation of the catalyst, a membrane electrode assembly, and a fuel cell. The catalyst of the present invention comprises an electronically conductive support and catalyst fine particles. The catalyst fine particles are supported on the support and are represented by the formula (1): PtuRuxGeyTz (1). In the formula, u, x, y and z mean 30 to 60 atm %, 20 to 50 atm %, 0.5 to 20 atm % and 0.5 to 40 atm %, respectively. When the element represented by T is Al, Si, Ni, W, Mo, V or C, the content of the T-element's atoms connected with oxygen bonds is not more than four times as large as that of the T-element's atoms connected with metal bonds on the basis of X-ray photoelectron spectrum (XPS) analysis.

Abstract: A catalyst includes a conductive carrier and catalyst particles. The catalyst particles are supported on the conductive carrier and have a composition represented by formula 1, below. An area of a peak derived from a metal bond of a T-element is 15% or more of an area of a peak derived from an oxygen bond of the T-element in a spectrum obtained by X-ray photoelectron spectroscopic method. PtxRuyTz??(1) where the T-element is at least one element selected from the group consisting of V, Nb and Hf, x is 30 to 60 at. %, y is 20 to 50 at. % and z is 5 to 50 at. %.

Abstract: A methanol oxidation catalyst is provided, which includes nanoparticles having a composition represented by the following formula (1): PtxRuyMozTu??(1) In the formula (1), the T-element is at least one selected from the group consisting of W and V, x is 20 to 80 at. %, y is 10 to 60 at. %, z is 1 to 30 at. % and u is 1 to 30 at. %. The area of the peak derived from oxygen bond of T-element is 80% or less of the area of the peak derived from metal bond of T-element in a spectrum measured by an X-ray photoelectron spectral method.

Abstract: A recovering method is provided, which includes contacting a solid component containing Ru with an aqueous solution to create a Ru compound, and causing the Ru compound to selectively elute in the aqueous solution. The aqueous solution is formed of at least one selected from the group consisting of aqueous solutions A, B, C, D, and E. The aqueous solution A comprises an acid and formic acid, alcohols, aldehydes, a compound having a hemiacetal structure or a compound having an acetal structure. The aqueous solution B comprises an acid and a compound which creates, in the coexistence thereof with the acid, formic acid, alcohols, aldehydes, a compound having a hemiacetal structure or a compound having an acetal structure. The aqueous solution C comprises an acid and sugars. The aqueous solution D comprises formic acid, and the aqueous solution E comprises oxalic acid.

Abstract: The present invention provides a catalyst having high activity and excellent stability, a process for preparation of the catalyst, a membrane electrode assembly, and a fuel cell. The catalyst of the present invention comprises an electronically conductive support and catalyst fine particles. The catalyst fine particles are supported on the support and are represented by the formula (1): PtuRuxGeyTz (1). In the formula, u, x, y and z mean 30 to 60 atm %, 20 to 50 atm %, 0.5 to 20 atm % and 0.5 to 40 atm %, respectively. When the element represented by T is Al, Si, Ni, W, Mo, V or C, the content of the T-element's atoms connected with oxygen bonds is not more than four times as large as that of the T-element's atoms connected with metal bonds on the basis of X-ray photoelectron spectrum (XPS) analysis.

Abstract: A methanol oxidation catalyst comprises a material of composition: PtxMzTau in which Pt is platinum, Ta is tantalum, M is an element includes at least one selected from the group consisting of V (vanadium), W (tungsten), Ni (nickel) and Mo (molybdenum), x is 40 to 98 at. %, z is 1.5 to 55 at. %, and u is 0.5 to 40 at. %. To maximize catalytic activity the mater al is preferably in the form of nanoparticles. The values of x, z and u are selected such that the element exhibits X-ray photoelectron spectroscopy peaks derived from an oxygen bond and a metal bond in which a peak area derived from the oxygen bond is twice or less of a peak area derived from the metal bond.

Abstract: A methanol oxidation catalyst is provided, which includes nanoparticles having a composition represented by the following formula (1): PtxRuyMozTu ??(1) In the formula (1), the T-element is at least one selected from the group consisting of W and V, x is 20 to 80 at. %, y is 10 to 60 at. %, z is 1 to 30 at. % and u is 1 to 30 at. %. The area of the peak derived from oxygen bond of T-element is 80% or less of the area of the peak derived from metal bond of T-element in a spectrum measured by an X-ray photoelectron spectral method.

Abstract: A methanol oxidation catalyst is provided, which includes nanoparticles having a composition represented by the following formula 1: PtxRuyTzQu ??formula 1 In the formula 1, the T-element is at least one selected from a group consisting of Mo, W and V and the Q-element is at least one selected from a group consisting of Nb, Cr, Zr and Ti, x is 40 to 90 at. %, y is 0 to 9.9 at. %, z is 3 to 70 at. % and u is 0.5 to 40 at. %. The area of the peak derived from oxygen bond of T-element is 80% or less of the area of the peak derived from metal bond of T-element in a spectrum measured by an X-ray photoelectron spectral method.

Abstract: This invention provides a process for producing a membrane electrode assembly which has high and stable catalytic activity, and suppressed deterioration in catalytic activity during operation, and can prevent a deterioration in performance attributable to a structural factor of the membrane electrode assembly. The process comprises the step of, after the washing/removing step, drying the catalyst electrode in an atmosphere having a lower oxygen partial pressure than the air. The anode/cathode is a covered catalyst electrode having a structure formed by supporting/depositing a catalytically active material composed mainly of platinum/ruthenium subjected to the potential holding step, the washing/removing step, and the drying step, on a porous electroconductive carrier to cover at least a part of the porous electroconductive carrier with the ion conductive material.

Abstract: This invention provides a highly active and stable catalyst, which is suitable for use in fuel cells while suppressing the amount of expensive noble metals used, i.e., platinum (Pt) and ruthenium (Ru), and a process for producing the catalyst, and a membrane electrode assembly and fuel cell using the catalyst. The catalyst comprises: an electro conductive support; and catalyst particles supported on the electro conductive support and having a composition represented by formula (1) PtuRuxMgyTz ??(1) wherein u is 30 to 60 atm %, x is 20 to 50 atm %, y is 0.5 to 20 atm %, and z is 0.

Abstract: There is provided a catalyst for a fuel cell, which simultaneously realizes excellent catalytic activity and catalytic stability. The catalyst for a fuel cell comprises a fine particle of a metal represented by formula: PtxRuySizT1u wherein T1 represents at least one element selected from the group consisting of nickel (Ni), tungsten (W), vanadium (V), and molybdenum (Mo); x=30 to 90 atomic %; y=0 to 50 atomic %; z=0.5 to 20 atomic %; and u=0.5 to 40 atomic %, or comprises a fine particle of a metal represented by formula: PtxRuySizT2u wherein T2 represents at least one element selected from the group consisting of hafnium (Hf), tin (Sn), zirconium (Zr), niobium (Nb), titanium (Ti), tantalum (Ta), chromium (Cr), and aluminum (Al); x=30 to 90 atomic %; y=0 to 50 atomic %; z=0.5 to 20 atomic %; and u=0.5 to 40 atomic %.

Abstract: A catalyst is provided and includes fine catalyst particles of a composition represented by formula (1): PtuRuxTayTz, in which T is at least one element selected from the group consisting of Hf, W, Ni, and V; u, x, y, and z are 10 to 98.9 atm %, 0.1 to 50 atm %, 0.5 to 35 atm %, and 0.5 to 35 atm %, respectively, or formula (2): PtuRuxTayTz, in which T is at least one element selected from the group consisting of Ct, Mo, Nb, Zr, and T; u, x, y, and z are 40 to 70 atm %, 0.1 to 50 atm %, 0.5 to 15 atm %, and 0.

Abstract: A catalyst includes a conductive carrier and catalyst particles. The catalyst particles are supported on the conductive carrier and have a composition represented by formula 1, below. An area of a peak derived from a metal bond of a T-element is 15% or more of an area of a peak derived from an oxygen bond of the T-element in a spectrum obtained by X-ray photoelectron spectroscopic method. PtxRuyTz ??(1) where the T-element is at least one element selected from the group consisting of V, Nb and Hf, x is 30 to 60 at. %, y is 20 to 50 at. % and z is 5 to 50 at. %.