Membrane electrode assembly with improved electrode

Abstract

A membrane electrode assembly comprises a polymer electrolyte interposed between an anode electrode and a cathode electrode, the anode electrode comprising an anode catalyst layer adjacent at least a portion of a first major surface of the polymer electrolyte, the cathode electrode comprising a cathode catalyst layer adjacent at least a portion of a second major surface of the polymer electrolyte; at least one of the anode and cathode catalyst layers comprising: a first catalyst composition comprising a noble metal; and a second composition comprising a metal oxide; wherein the second composition has been treated with a fluoro-phosphonic acid compound.

1 . A membrane electrode assembly, comprising:
 a polymer electrolyte interposed between an anode electrode and a cathode electrode, the anode electrode comprising an anode catalyst layer adjacent at least a portion of a first surface of the polymer electrolyte, the cathode electrode comprising a cathode catalyst layer adjacent at least a portion of a second surface of the polymer electrolyte, at least one of the anode and cathode catalyst layers comprising:   a first catalyst composition comprising a noble metal; and   a second composition comprising a metal oxide, the second composition has been treated with a fluoro-phosphonic acid compound.   
     
     
         2 . The membrane electrode assembly of  claim 1 , wherein the noble metal of the first catalyst composition comprises platinum or a platinum alloy. 
     
     
         3 . The membrane electrode assembly of  claim 1 , wherein the noble metal of the first catalyst composition is selected from the group consisting of platinum, gold, ruthenium, iridium, osmium, palladium, silver; and compounds, alloys, solid solutions, and mixtures thereof. 
     
     
         4 . The membrane electrode assembly of  claim 1 , wherein the metal oxide of the second composition is a single-phase solid solution comprising ruthenium. 
     
     
         5 . The membrane electrode assembly of  claim 1 , wherein the metal oxide of the second composition is a single-phase solid solution comprising iridium. 
     
     
         6 . The membrane electrode assembly of  claim 1 , wherein the metal oxide of the second composition is selected from the group consisting of ruthenium oxide, iridium oxide, titanium oxide, cerium oxide, and their mixtures, solid solutions and composites thereof. 
     
     
         7 . The membrane electrode assembly of  claim 1 , wherein the metal oxide of the second composition is supported on a support material. 
     
     
         8 . The membrane electrode assembly of  claim 1 , wherein the fluoro-phosphonic acid compound is a fluoroalkyl-phosphonic acid compound. 
     
     
         9 . The membrane electrode assembly of  claim 8 , wherein the fluoro-phosphonic acid compound is 2-perfluorohexyl ethyl phosphonic acid. 
     
     
         10 . The membrane electrode assembly of  claim 8 , wherein the fluoro-phosphonic acid compound is (1H,1H,2H,2H-heptadecafluorodec-1-yl) phosphonic acid. 
     
     
         11 . The membrane electrode assembly of  claim 1 , wherein the second composition comprises about 1.0 wt % to about 20.0 wt % of the fluoro-phosphonic acid compound. 
     
     
         12 . The membrane electrode assembly of  claim 1 , wherein the fluoro-phosphonic acid compound has a molecular weight of at least 200. 
     
     
         13 . The membrane electrode assembly of  claim 1 , wherein the first catalyst composition is in a first discrete layer and the second composition is in a second discrete layer in the at least one of the anode and cathode catalyst layers. 
     
     
         14 .- 24 . (canceled)