Method for preparing colloidal solution and carrier having colloidal particles fixed on surface thereof, fuel cell cathode, fuel cell anode and method for preparing the same and fuel cell using the same, and low temperature oxidation catalyst, method for preparing the same and fuel cell fuel modifying device using the same

Abstract

A method for forming colloidal particles by boiling a solution containing a metal salt and a reducing agent; and a method for preparing a colloidal solution wherein the concentration of the metal salt in the solution is 1×10 −4 mol/L or more and less than 4×10 −4 mol/L; the equivalent concentration of the reducing agent is four times or more and 20 times or less the equivalent concentration of the metal salt; and the reaction time is 60 minutes or more and 300 minutes or less. A carrier wherein colloidal particles are fixed on the surface of a substrate by applying the colloidal solution prepared by the above-described method. Methods for manufacturing a fuel cell cathode, a fuel cell anode, and a low temperature oxidation catalyst wherein a colloidal solution prepared in the state wherein a solution containing a metal salt and a reducing agent is boiled to remove dissolved oxygen is applied to a substrate and colloidal particles are fixed on the substrate.

1 . A colloidal solution preparing method for forming colloidal particles by boiling a solution containing a metal salt and a reducing agent, 
 wherein the concentration of the metal salt in said solution is 1×10 −4  mol/L or more and less than 4×10 −4  mol/L; the equivalent concentration of the reducing agent is four times or more and 20 times or less the equivalent concentration of the metal salt; and the reaction time is 60 minutes or more and 300 minutes or less.    
     
     
         2 . A colloidal solution preparing method for forming colloidal particles by boiling a solution containing a metal salt and a reducing agent, 
 wherein the concentration of the metal salt in said solution is 4×10 −4  mol/L or more and less than 6×10 −4  mol/L; the equivalent concentration of the reducing agent in four times or more and 20 times or less the equivalent concentration of the metal salt; and the reaction time is 30 minutes or more and 150 minutes or less.    
     
     
         3 . A colloidal solution preparing method for forming colloidal particles by boiling a solution containing a metal salt and a reducing agent, 
 wherein the concentration of the metal salt in said solution is 6×10 −4  mol/L or more and 15×10 −4  mol/L or less; the equivalent concentration of the reducing agent in four times or more and 20 times or less the equivalent concentration of the metal salt; and the reaction time is 30 minutes or more and 90 minutes or less.    
     
     
         4 . A colloidal solution preparing method for forming colloidal particles by boiling a solution containing a metal salt and a reducing agent, 
 wherein the concentration of the metal salt in said solution is 4×10 −4  mol/L or more and less than 6×10 −4  mol/L; the equivalent concentration of the reducing agent in twice or more and less than four times the equivalent concentration of the metal salt; and the reaction time is 60 minutes or more and 120 minutes or less.    
     
     
         5 . A colloidal solution preparing method for forming colloidal particles by boiling a solution containing a metal salt and a reducing agent, 
 wherein the concentration of the metal salt in said solution is 6×10 −4  mol/L or more and 15×10 −4  mol/L or less; the equivalent concentration of the reducing agent in twice or more and less than four times the equivalent concentration of the metal salt; and the reaction time is 30 minutes or more and 240 minutes or less.    
     
     
         6 . A colloidal solution preparing method for forming colloidal particles by boiling a solution containing a metal salt and a reducing agent, 
 wherein the concentration of the metal salt in said solution is 4×10 4 mol/L or more and less than 6×10 −4  mol/L; the equivalent concentration of the reducing agent is once or more and less than twice the equivalent concentration of the metal salt; and the reaction time is 60 minutes or more and 120 minutes or less.    
     
     
         7 . A colloidal solution preparing method for forming colloidal particles by boiling a solution containing a metal salt and a reducing agent, 
 wherein the concentration of the metal salt in said solution is 6×10 −4  mol/L or more and 15×10 −4  mol/L or less; the equivalent concentration of the reducing agent in once or more and less than twice the equivalent concentration of the metal salt; and the reaction time is 30 minutes or more and 120 minutes or less.    
     
     
         8 . The colloidal solution preparing method according to  claim 1  wherein said reducing agent is a citrate.  
     
     
         9 . The colloidal solution preparing method according to  claim 1  wherein the average particle diameter of said colloidal particles is 1.6 to 5 nm.  
     
     
         10 . A carrier wherein colloidal particles are fixed on the surface of a substrate by applying the colloidal solution prepared by the method according to  claim 1 .  
     
     
         11 . The carrier according to  claim 10  wherein said substrate is glass fiber or scale-like glass.  
     
     
         12 . The carrier according to  claim 10  wherein said substrate is porous.  
     
     
         13 . A method for manufacturing a fuel cell cathode wherein a colloidal solution prepared in the state wherein a solution containing a metal salt and a reducing agent is boiled to remove dissolved oxygen is applied to a substrate, and colloidal particles are fixed on said substrate.  
     
     
         14 . The method for manufacturing a fuel cell cathode according to  claim 13 , wherein said metal salt is chloroplatinic acid.  
     
     
         15 . The method for manufacturing a fuel cell cathode according to  claim 13 , wherein said reducing agent is sodium citrate.  
     
     
         16 . The method for manufacturing a fuel cell cathode according to  claim 13 , wherein the average particle diameter of said colloidal particles is 1.6 to 5 nm.  
     
     
         17 . A fuel cell cathode manufactured using the method according to  claim 13 .  
     
     
         18 . A fuel cell using the cathode according to  claim 17 .  
     
     
         19 . A method for manufacturing a fuel cell anode wherein a colloidal solution prepared in the state wherein a solution containing a metal salt and a reducing agent is boiled to remove dissolved oxygen is applied to a substrate, and colloidal particles are fixed on said substrate.  
     
     
         20 . The method for manufacturing a fuel cell anode according to  claim 19 , wherein said metal salt is chloroplatinic acid.  
     
     
         21 . The method for manufacturing a fuel cell anode according to  claim 19 , wherein said reducing agent is sodium citrate.  
     
     
         22 . The method for manufacturing a fuel cell anode according to  claim 19 , wherein the average particle diameter of said colloidal particles is 1.6 to 5 nm.  
     
     
         23 . A fuel cell anode manufactured using the method according to  claim 19 .  
     
     
         24 . A fuel cell using the anode according to  claim 23 .  
     
     
         25 . A method for preparing a low-temperature oxidation catalyst wherein a colloidal solution prepared in the state wherein a solution containing a metal salt and a reducing agent is boiled to remove dissolved oxygen is applied to a substrate, and colloidal particles are fixed on said substrate.  
     
     
         26 . The method for preparing a low-temperature oxidation catalyst according to  claim 25  wherein said metal salt is chloroplatinic acid.  
     
     
         27 . The method for preparing a low-temperature oxidation catalyst according to  claim 25  wherein said reducing agent is sodium citrate.  
     
     
         28 . The method for preparing a low-temperature oxidation catalyst according to  claim 25 , wherein the average particle diameter of said colloidal particles is 1.6 to 5 nm.  
     
     
         29 . A low-temperature oxidation catalyst prepared using the method according to  claim 25 .  
     
     
         30 . A fuel modifying device for a fuel cell using the low-temperature oxidation catalyst according to  claim 29.