Catalyst materials for fuel cells

Abstract

An improved direct liquid-feed fuel cell having a solid membrane electrolyte for electrochemical reactions of an organic fuel. Improvements in interfacing of the catalyst layer and the membrane and activating catalyst materials are disclosed.

What is claimed is:  
     
         1 . A method for fabricating a catalyst layer for a fuel cell, comprising: 
 preparing a catalyst material for either the electro-reduction or electro-oxidation reaction in the fuel cell;    introducing a substance in the catalyst material, wherein the substance is insoluble in the catalyst material; and    subsequently removing the insoluble substance from the catalyst material to increase a surface area of the catalyst material compared to the catalyst material prior to introducing and removing the substance.    
     
     
         2 . The method as in  claim 1 , wherein the catalyst material comprises a catalyst of about 7-10 wt. %, perfluorovinylether sulfonic acid of about 60-70 wt. %, and polytetrafluoroethylene of about 15-20 wt. %.  
     
     
         3 . The method as in  claim 2  wherein the catalyst material is obtained by: 
 mixing the catalyst and the polytetrafluoroethylene in a diluted solution to form a mixture liquid;  
 performing sonication to the mixture liquid;  
 subsequently adding the perfluorovinylether sulfonic acid in a diluted solution to the mixture liquid to form a new mixture liquid; and  
 performing sonication to the new mixture liquid.  
 
     
     
         4 . The method as in  claim 2 , wherein the catalyst comprises platinum and ruthenium.  
     
     
         5 . The method as in  claim 1 , wherein the insoluble substance is a surface active substance which prevents particle agglomeration and is volatilized at a high temperature.  
     
     
         6 . The method as in  claim 5 , wherein the surface active substance is a non-ionic surfactant.  
     
     
         7 . A method for fabricating a catalyst material for a fuel cell: 
 mixing a catalyst and a polytetrafluoroethylene in a diluted solution to form a mixture liquid;    performing sonication to the mixture liquid;    subsequently adding a perfluorovinylether sulfonic acid in a diluted solution to the mixture liquid to form a new mixture liquid solution;    performing sonication to the new mixture liquid solution; and    placing dry ice into the new mixture liquid to evaporate the liquid portion without agglomeration and growth of particles to form a catalyst material.    
     
     
         8 . The method as in  claim 7 , wherein the catalyst material comprises the catalyst of about 7-10 wt. %, the perfluorovinylether sulfonic acid of about 60-70 wt. %, and the polytetrafluoroethylene of about 15-20 wt. %.  
     
     
         9 . A method for fabricating a catalyst material for a fuel cell: 
 mixing a catalyst and a polytetrafluoroethylene in a diluted solution to form a mixture liquid;    performing sonication to the mixture liquid;    subsequently adding a perfluorovinylether sulfonic acid in a diluted solution to the mixture liquid to form a new mixture liquid solution;    performing sonication to the new mixture liquid solution; and    adding a gas through the new mixture liquid solution to cause bubbles to promote formation of a foam-type catalyst material.    
     
     
         10 . The method as in  claim 9 , wherein the catalyst material comprises the catalyst of about 7-10 wt. %, the perfluorovinylether sulfonic acid of about 60-70 wt. %, and the polytetrafluoroethylene of about 15-20 wt. %.  
     
     
         11 . The method as in  claim 9 , wherein the gas is an inert gas, nitrogen, or air.  
     
     
         12 . A method for fabricating a catalyst material for a fuel cell, comprising: 
 mixing a catalyst of about 7-10 wt. %, a perfluorovinylether sulfonic acid of about 60-70 wt. %, and a polytetrafluoroethylene of about 15-20 wt. % to form a catalyst material; and    thermally quenching the catalyst material from a high temperature to a low temperature to activating the catalyst material.    
     
     
         13 . The method as in  claim 12 , wherein the thermal quenching is performed in a liquid nitrogen to decrease the temperature from an ambient temperature to about 77K.  
     
     
         14 . The method as in  claim 12 , wherein the catalyst comprises platinum and ruthenium with a relative percentage ratio from about 10 wt. % platinum and 90 wt. % ruthenium to about 90 wt. % platinum and 10 wt. % ruthenium.  
     
     
         15 . A catalyst material for a fuel cell, comprising: 
 a catalyst comprising tungsten carbide;    a perfluorovinylether sulfonic acid; and    a polytetrafluoroethylene.    
     
     
         16 . The material as in  claim 15 , wherein said catalyst further includes ruthenium or ruthenium oxide.  
     
     
         17 . The material as in  claim 16 , wherein said catalyst further comprises platinum.  
     
     
         18 . A catalyst material for a fuel cell, comprising: 
 a catalyst comprising zirconium dioxide;    a perfluorovinylether sulfonic acid; and    a polytetrafluoroethylene.    
     
     
         19 . The material as in  claim 18 , wherein said catalyst further comprises platinum.  
     
     
         20 . The material as in  claim 19 , wherein said catalyst further comprises ruthenium dioxide.  
     
     
         21 . A catalyst material for a fuel cell, comprising: 
 a catalyst comprising zeolites incorporated with platinum and ruthenium;    a perfluorovinylether sulfonic acid; and    a polytetrafluoroethylene.    
     
     
         22 . The material as in  claim 21 , wherein said catalyst further includes iridium in said zeolites.  
     
     
         23 . The material as in  claim 21 , wherein said catalyst further includes osmium in said zeolites.  
     
     
         24 . The material as in  claim 21 , wherein said catalyst further includes tungsten in said zeolites.  
     
     
         25 . The material as in  claim 21 , further comprising an electrically-conductive carbon material.