Electrode catalyst layer for fuel cell

Abstract

An electrode catalyst layer for use in a fuel cell, the layer having a composite particle material in which catalyst particles are supported on conductive particles, a proton conductive polymer and a metal oxide, wherein said metal oxide is non-particulate.

1 . An electrode catalyst layer for use in a fuel cell, the layer comprising a composite particle material in which catalyst particles are supported on conductive particles, a proton conductive polymer and a metal oxide, wherein said metal oxide is non-particulate.  
     
     
         2 . The electrode catalyst layer according to  claim 1 , wherein part of the surface of said catalyst particles is coated with the proton conductive polymer.  
     
     
         3 . The electrode catalyst layer according to  claim 1  or  2 , wherein said proton conductive polymer contains said metal oxide.  
     
     
         4 . The electrode catalyst layer according to any one of  claims 1  to  3 , wherein said metal oxide is silica.  
     
     
         5 . The electrode catalyst layer according to any one of  claims 1  to  4 , wherein the content of said metal oxide is 0.001 mg/cm 2  or more and 10 mg/cm 2  or less in terms of loading amount in relation to projected area of the electrode.  
     
     
         6 . The electrode catalyst layer according to any one of  claims 1  to  5 , wherein said metal oxide is obtained by subjecting a metal oxide precursor to hydrolysis and polycondensation reactions.  
     
     
         7 . The electrode catalyst layer according to any one of  claims 1  to  6 , which is obtained by a method comprising at least the following steps of: 
 (a) forming a polymer-containing aggregate containing said composite particle material and said proton conductive polymer; and  
 (b) thereafter converting a metal oxide precursor corresponding to said metal oxide into said metal oxide by impregnating into the aggregate said metal oxide precursor and successively by subjecting the precursor to the hydrolysis and polycondensation reactions.  
 
     
     
         8 . A gas diffusion electrode, comprising the electrode catalyst layer according to any one of  claims 1  to  7 .  
     
     
         9 . A membrane/electrode assembly, comprising the electrode catalyst layer according to any one of  claims 1  to  7 .  
     
     
         10 . A solid polymer type fuel cell, comprising the electrode catalyst layer according to any one of  claims 1  to  7 .