Carbon monoxide tolerant electrocatalyst with low platinum loading and a process for its preparation

Abstract

An electrocatalyst is provided for use in a fuel cell that has low platinum loading and a high tolerance to carbon monoxide poisoning. The fuel cell anode includes an electrocatalyst that has a conductive support material, ruthenium nanoparticles reduced in H 2 and a Group VIII noble metal in an amount of between about 0.1 and 25 wt % of the ruthenium nanoparticles, preferably between about 0.5 and 15 wt %. The preferred Group VIII noble metal is platinum. In one embodiment, the anode can also have a perfluorinated polymer membrane on its surface.

1 . An anode for use in the oxidation of hydrogen in a fuel cell, said anode comprising an electrocatalyst comprising; 
 conductive support material;    uthenium nanoparticles reduced in H 2 ; and    Group VIII noble metal;    wherein the amount of said Group VIII noble metal is between about 0.2 and 15 wt % of said ruthenium nanoparticles.    
     
     
         2 . The anode for use in the oxidation of hydrogen in a fuel cell according to  claim 1 , wherein said Group VIII noble metal is platinum.  
     
     
         3 . The anode for use in the oxidation of hydrogen in a fuel cell according to  claim 1 , wherein said ruthenium nanoparticles have a size of from about 2 to about 20 nm.  
     
     
         4 . The anode for use in the oxidation of hydrogen in a fuel cell according to  claim 1 , wherein said conductive support material is a finely divided conductive support material.  
     
     
         5 . The anode for use in the oxidation of hydrogen in a fuel cell according to  claim 1 , wherein said conductive support material is carbon black, graphiltized carbon, graphite or active carbon.  
     
     
         6 . The anode for use in the oxidation of hydrogen in a fuel cell according to  claim 2 , wherein the electrocatalyst is from about 10 to about 40 wt % platinum and ruthenium and from about 60 to about 90 wt % conductive material.  
     
     
         7 . The anode for use in the oxidation of hydrogen in a fuel cell according to  claim 1 , wherein said Group VIII noble metal is on the surface of said electrocatalyst.  
     
     
         8 . The anode for use in the oxidation of hydrogen in a fuel cell according to  claim 1 , further comprising a perfluorinated polymer membrane.  
     
     
         9 . The proton-exchange membrane fuel cell according to  claim 1 , wherein said ruthenium nanoparticles are suspended in water or a solvent.  
     
     
         10 . A proton-exchange membrane fuel cell comprising an anode which comprises an electrocatalyst, said electrocatalyst comprising: 
 conductive support material;    uthenium nanoparticles reduced in H 2 ; and    Group VIII noble metal;    wherein the amount of said Group VIII noble metal is between about 0.2 and 15 wt % of said ruthenium nanoparticles.    
     
     
         11 . The proton-exchange membrane fuel cell according to  claim 10 , wherein said Group VIII noble metal is platinum.  
     
     
         12 . The proton-exchange membrane fuel cell according to  claim 11 , wherein the electrocatalyst is from about 10 to about 40 wt % platinum and ruthenium and from about 60 to about 90 wt % conductive material.  
     
     
         13 . The proton-exchange membrane fuel cell according to  claim 10 , wherein said ruthenium nanoparticles have a size of from about 2 to about 20 nm.  
     
     
         14 . The proton-exchange membrane fuel cell according to  claim 10 , wherein said conductive support material is a finely divided conductive support material.  
     
     
         15 . The proton-exchange membrane fuel cell according to  claim 10  wherein said conductive support material is carbon black, graphitized carbon, graphite or active carbon.  
     
     
         16 . The proton-exchange membrane fuel cell according to  claim 10 , wherein said Group VIII noble metal is on the surface of said electrocatalyst.  
     
     
         17 . The proton-exchange membrane fuel cell according to  claim 10 , wherein said ruthenium nanoparticles are suspended in water or a solvent.  
     
     
         18 . A process for preparing a supported electrocatalyst comprising: 
 depositing ruthenium nanoparticles on an electrically conductive support material;    heating said electrically conductive support material with deposited ruthenium nanoparticles in H 2 ;    cooling said electrically conductive support material with deposited ruthenium nanoparticles; and    contacting said electrically conductive support material with deposited ruthenium nanoparticles with a solution comprising a Group VIII noble metal compound to form a supported electrocatalyst.    
     
     
         19 . The process for preparing a supported electrocatalyst according to  claim 18 , wherein said Group VIII noble metal compound is a platinum compound.  
     
     
         20 . The process for preparing a supported electrocatalyst according to  claim 19 , wherein the electrocatalyst is from about 10 to about 40 wt % platinum and ruthenium and from about 60 to about 90 wt % conductive material.  
     
     
         21 . The process for preparing a supported electrocatalyst according to  claim 18 , wherein said heating is carried out at a temperature of from about 100 to about 400° C.  
     
     
         22 . The process for preparing a supported electrocatalyst according to  claim 18 , wherein said electrically conductive support material with deposited ruthenium nanoparticles is cooled to a temperature of from about 20 to about 40° C.  
     
     
         23 . The process for preparing a supported electrocatalyst according to  claim 18 , wherein said solution comprising said platinum compound is an aqueous solution.  
     
     
         24 . The process for preparing a supported electrocatalyst according to  claim 18 , wherein said platinum compound is H 2 PtCl 6 .  
     
     
         25 . The process for preparing a supported electrocatalyst according to  claim 18 , wherein a thin layer of platinum is formed on said ruthenium nanoparticles.  
     
     
         26 . The process for preparing a supported electrocatalyst according to  claim 18 , further comprising contacting said supported electrocatalyst with water.  
     
     
         27 . The process for preparing a supported electrocatalyst according to  claim 26 , further comprising filtering said supported electrocatalyst.  
     
     
         28 . The process for preparing a supported electrocatalyst according to  claim 26 , further comprising drying said supported electrocatalyst.  
     
     
         29 . The process for preparing a supported electrocatalyst according to  claim 18 , wherein said electrically conductive support material is carbon black, graphitized carbon, graphite or active carbon.  
     
     
         30 . The process for preparing a supported electrocatalyst according to  claim 19 , wherein the weight percent ratio of platinum to ruthenium is from about 0.02:1 to about 0.15:1.  
     
     
         31 . The process for preparing a supported electrocatalyst according to  claim 18 , wherein said Group VIII noble metal is on the surface of said electrocatalyst.  
     
     
         32 . The process for preparing a supported electrocatalyst according to  claim 26 , further comprising mixing said supported electrocatalyst and water to form a suspension.  
     
     
         33 . The process for preparing a supported electrocatalyst according to  claim 32 , further comprising evaporating said water to form an homogenous electrocatalyst.  
     
     
         34 . The process for preparing a supported electrocatalyst according to  claim 33 , further comprising contacting said homogenous electrocatalyst with a solution comprising a perfluorinated polymer.  
     
     
         35 . The proton-exchange membrane fuel cell according to  claim 18 , wherein said ruthenium nanoparticles are suspended in water or a solvent to form a slurry.  
     
     
         36 . The process for preparing a supported electrocatalyst according to  claim 35 , further comprising contacting a membrane comprising a perfluorinated polymer with said slurry.  
     
     
         37 . The process for preparing a supported electrocatalyst according to  claim 36 , further comprising depositing said membrane and slurry on a carbon substrate.