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AssigneeJGC Catalysts and Chemicals Ltd.
InventorsYoichi Ishihara, Toshiharu Hirai, Michio Komatsu
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Provided is a process for producing electrode catalyst fine particles capable of affording formed catalysts such as membranes excellent in uniformity and strength and also employable as catalyst to exhibit high catalytic activity over long periods because fine metal particles are highly distributed on carriers to make particle growth or the like less likely to occur. Electrode catalyst fine particles comprise fine particles which have an average particle diameter of 10 nm to 10 μm and in which fine metal particles are supported on carrier particles, wherein a potential difference (absolute value of (II) minus (I)) between a flow potential (I) of a water dispersion of the fine metal particles at 1 wt % concentration and a pH of 3 to 8 and a flow potential (II) of a water dispersion of the carrier particles at 1 wt % concentration and a pH of 4 to 10, is in the range of 10 to 3000 mV.
Electrode catalyst fine particles comprising fine metal particles consisting essentially of one or more metals selected from the group consisting of Au, Ag, Pd, Pt, Rh, Cu, Fe, Ni, Co, Sn, Ti, In, Al, Ta, Sb, Rn, Mo and Cr and having an average particle diameter of 2 to 200 nm supported on carrier particles having an average particle diameter of 10 nm to 10 μm, wherein a potential difference (absolute value of (II) minus (I)) between a flow potential (I) of a water dispersion of the fine metal particles at 1 wt % concentration and a pH of 3 to 8 and a flow potential (II) of a water dispersion of the carrier particles at 1 wt % concentration and a pH of 4 to 10, is in the range of 10 to 3000 mV, and wherein the electrode catalyst fine particle is obtained by mixing a dispersion of the fine metal particles and a dispersion of the carrier particles, and then adjusting the pH of the dispersion mixture in the range of 2 to 10.
A process for producing a dispersion of electrode catalyst fine particles, which process comprises mixing a dispersion of fine metal particles consisting essentially of one or more metals selected from the group consisting of Au, Ag, Pd, Pt, Rh, Cu, Fe, Ni, Co, Sn, Ti, In, Al, Ta, Sb, Ru, Mo and Cr and having an average particle diameter of 2 to 200 nm and a dispersion of carrier particles having an average particle diameter of 10 nm to 10 μm, the fine metal particles being dispersed in water at 1 wt % concentration and a pH of 3 to 8 to have a flow potential (I) and the carrier particles being dispersed in water at 1 wt % concentration and a pH of 4 to 10 to have a flow potential (II) such that the potential difference (absolute value of (II) minus (I)) between the flow potentials (I) and (II) is in the range of 10 to 3000 mV, and adjusting the pH of the dispersion mixture in the range of 2 to 10.
Dependencies are inferred from the claim text.