Synthesis of organic passivated noble metal nanocrystals and uses thereof on electrodes

Abstract

A method of modifying an electrolysis electrode is provided that includes applying nanocrystals each having a passivating layer of organic molecules, the organic molecules having a molecular weight of between 46 and 800 Daltons to the electrolysis electrode to create a coated surface thereon, an infiltrated porous volume therein, or a combination thereof. The coated surface is then exposed to an energy source under conditions that volatilize the passivating layer of organic molecules to modify the electrolysis electrode.

1 . A method of modifying an electrolysis electrode comprising:
 applying a plurality of nanocrystals each having a passivating layer of organic molecules, the organic molecules having a molecular weight of between 46 and 800 Daltons to the electrolysis electrode to create a coated surface thereon, an infiltrated porous volume therein, or a combination thereof; and   exposing the coated surface to an energy source under conditions that volatilize the passivating layer of organic molecules to modify the electrolysis electrode.   
     
     
         2 . The method of  claim 1  wherein the plurality of nanocrystals are one or more noble metals. 
     
     
         3 . The method of  claim 1  wherein the plurality of nanocrystals are Pt, Pd, Au, or alloys containing at least 10 atomic percent of the any one of the aforementioned. 
     
     
         4 . The method of  claim 1  wherein the plurality of nanocrystals are graphitic carbon. 
     
     
         5 . The method of  claim 1  wherein the plurality of nanocrystals have a maximal linear extent of from 1 to 5 nanometers. 
     
     
         6 . The method of  claim 5  wherein the maximal linear extent is the same in three orthogonal directions. 
     
     
         7 . The method of  claim 5  wherein the plurality of nanocrystals are spherical. 
     
     
         8 . The method of  claim 5  wherein the plurality of nanocrystals are faceted. 
     
     
         9 . The method of  claim 1  wherein the plurality of nanocrystals are monodisperse within 20 percent. 
     
     
         10 . The method of  claim 1  wherein the surface protecting molecule is A-L-(Q) n  where L is C 1 -C 30  alkyl, C 5 -C 30  cycloalkyl, C 2 -C 30  alkenyl, C 6 -C 30  cycloalkenyl, C 6 -C 30 _aromatic;
 Q is a heteroatom containing moiety capable of coordinating a metal ion, the heteroatom including oxygen, nitrogen or sulfur; the heteroatom being present as an alcohol, carbonyl, carboxyl, phosphatidyl, sulfonyl, sulfinyl, nitrosyl, amino, imido, azide, thiol, ester, ether, secondary amino, thioester, thioether, silanol, siloxyl; and A is a water solubility imparting moiety illustratively including hydrogen, alcohol, sulfonyl, sulfhydryl, amino, secondary amino, phosphatidyl, carboxyl, phenyl, nitro-, ester, ether, thioester and thioether; n is an integer between 1 and 4 and corresponding to mono through tetradentate ligands. 
 
     
     
         11 . The method of  claim 1  wherein the energy source is heat. 
     
     
         12 . The method of  claim 11  wherein the heat is applied such that the surface is heated to a temperature of between 190 and 400 degrees Celsius. 
     
     
         13 . The method of  claim 1  wherein the energy source is actinic radiation. 
     
     
         14 . The method of  claim 1  further comprising heating the coated surface to a size dependent temperature sufficient to anneal or melt the plurality of nanocrystals to the surface. 
     
     
         15 . The method of  claim 1  further comprising passing current through the electrolysis electrode after the applying step. 
     
     
         16 . The method of  claim 1  wherein the plurality of nanocrystals are applied as a solution or aerosol with a solvent in which the passivating layer of organic molecules soluble. 
     
     
         17 . The method of  claim 1  wherein the plurality of nanocrystals are applied to extent to cover from 0.01 to 30 percent of the surface. 
     
     
         18 . An electrode produced by the method of  claim 1 . 
     
     
         19 . The electrode of  claim 18  wherein the electrode is a proton exchange membrane composition. 
     
     
         20 . The electrode of  claim 18  wherein the electrode is a metallic blade electrode.