Abstract: An object is to provide a catalyst particle that can exhibit high activity. The catalyst particle is an alloy particle formed of platinum atom and a non-platinum metal atom, wherein (i) the alloy particle has an L12 structure as an internal structure and has an extent of ordering of L12 structure in the range of 30 to 100%, (ii) the alloy particle has an LP ratio calculated by CO stripping method of 10% or more, and (iii) the alloy particle has a dN/dA ratio in the range of 0.4 to 1.0.

Abstract: An object is to provide a catalyst particle that can exhibit high activity. The catalyst particle is an alloy particle formed of platinum atom and a non-platinum metal atom, wherein (i) the alloy particle has an L12 structure as an internal structure and has an extent of ordering of L12 structure in the range of 30 to 100%, (ii) the alloy particle has an LP ratio calculated by CO stripping method of 10% or more, and (iii) the alloy particle has a dN/dA ratio in the range of 0.4 to 1.0.

Abstract: An object is to provide a catalyst particle that can exhibit high activity. The catalyst particle is an alloy particle formed of platinum atom and a non-platinum metal atom, wherein (i) the alloy particle has an L12 structure as an internal structure and has an extent of ordering of L12 structure in the range of 30 to 100%, (ii) the alloy particle has an LP ratio calculated by CO stripping method of 10% or more, and (iii) the alloy particle has a dN/dA ratio in the range of 0.4 to 1.0.

Abstract: An object is to provide a catalyst particle that can exhibit high activity. The catalyst particle is an alloy particle formed of platinum atom and a non-platinum metal atom, wherein (i) the alloy particle has an L12 structure as an internal structure and has an extent of ordering of L12 structure in the range of 30 to 100%, (ii) the alloy particle has an LP ratio calculated by CO stripping method of 10% or more, and (iii) the alloy particle has a dN/dA ratio in the range of 0.4 to 1.0.

Abstract: When stopping an operation of a fuel cell power plant, a controller (30) first stops fuel gas supply to an anode (2), then supplies a dry oxidant gas to a cathode (3) such that the output voltage of the fuel cell stack (1) decreases. The controller (30) then connects a secondary battery (31) to the fuel cell stack (1) so as to consume an output power generated by a reaction of the residual fuel gas in the anode (2). After this processing, the controller (30) replaces the residual fuel gas in the anode (2) with dry oxidant gas, then maintains the fuel cell stack (1) in a closed state, thereby preventing local cell formation in the anode due to mixing of the residual fuel gas with oxidant gas, and hence preventing corrosion of a catalyst layer of the cathode (3) due to local cell corrosion.

Abstract: A fuel cell has an anode, a cathode, and a proton-exchange membrane disposed between the anode and cathode. An exhaust anode gas exhausted from an outlet of the anode is directed back to an inlet of the anode. Hydrogen is added to the exhaust anode gas before the exhaust anode gas reaches the inlet.

Abstract: When stopping an operation of a fuel cell power plant, a controller (30) first stops fuel gas supply to an anode (2), then supplies a dry oxidant gas to a cathode (3) such that the output voltage of the fuel cell stack (1) decreases. The controller (30) then connects a secondary battery (31) to the fuel cell stack (1) so as to consume an output power generated by a reaction of the residual fuel gas in the anode (2). After this processing, the controller (30) replaces the residual fuel gas in the anode (2) with dry oxidant gas, then maintains the fuel cell stack (1) in a closed state, thereby preventing local cell formation in the anode due to mixing of the residual fuel gas with oxidant gas, and hence preventing corrosion of a catalyst layer of the cathode (3) due to local cell corrosion.

Abstract: A fuel cell has an anode, a cathode, and a proton-exchange membrane disposed between the anode and cathode. An exhaust anode gas exhausted from an outlet of the anode is directed back to an inlet of the anode. Hydrogen is added to the exhaust anode gas before the exhaust anode gas reaches the inlet.