Method of producing electrocatalyst coated electrode by electrochemical oxidation

Abstract

A method comprises applying a slurry to one or more surfaces of a conductive substrate to form a precursor coating and provide a precursor coated substrate, wherein the slurry includes precursor particles comprising one or more precursor compounds in a slurry medium, and electrochemically oxidizing the one or more precursor compounds to chemically convert the one or more precursor compounds to one or more catalyst compounds and form catalyst particles adhered to the one or more surfaces of the conductive substrate to provide a catalyst coated substrate.

1 . A method comprising:
 applying a slurry to one or more surfaces of a conductive substrate to form a precursor coating and provide a precursor coated substrate, wherein the slurry includes precursor particles comprising one or more precursor compounds in a slurry medium; and   electrochemically oxidizing the one or more precursor compounds to chemically convert the one or more precursor compounds to one or more catalyst compounds and form catalyst particles adhered to the one or more surfaces of the conductive substrate to provide a catalyst coated substrate.   
     
     
         2 . The method of  claim 1 , wherein electrochemically oxidizing the one or more precursor compounds comprises exposing the precursor coated substrate to a caustic solution while performing a specified electrochemical processing method to the precursor coated substrate that chemically converts the one or more precursor compounds to the one or more catalyst compounds. 
     
     
         3 . The method of  claim 2 , wherein the specified electrochemical processing method comprises chronoamperometry, chronopotentiometry, cyclic voltammetry, or a combination thereof. 
     
     
         4 . The method of  claim 1 , wherein the one or more catalyst compounds comprise a spinel with the general chemical formula AB 2 O 4 , wherein both A and B are elements comprising at least one of: a Group 1 metal, a Group 2 metal), a transition metal, a lanthanide series metal, a post-transition metal, a metalloid, sulfur (S), or phosphorus (P). 
     
     
         5 . The method of  claim 4 , wherein A comprises one or more of: nickel (Ni), zinc (Zn), copper (Cu), cobalt (Co), iron (Fe), lithium (Li), magnesium (Mg), calcium (Ca), barium (Ba), manganese (Mn), germanium (Ge), cadmium (Cd), lanthanide (La), Yttrium (Y), chromium (Cr), molybdenum (Mo), ruthenium (Ru), and iridium (Jr). 
     
     
         6 . The method of  claim 4 , wherein B comprises one or more of: cobalt (Co), iron (Fe), chromium (Cr), aluminum (Al), manganese (Mn), nickel (Ni), gallium (Ga), selenium (Se), molybdenum (Mo), ruthenium (Ru), sulfur (S), and tellurium (Te). 
     
     
         7 . The method of  claim 1 , further comprising drying the precursor coating to provide a dried precursor coating before electrochemically oxidizing the one or more precursor compounds to chemically convert the one or more precursor compounds to one or more catalyst compounds. 
     
     
         8 . The method of  claim 1 , further comprising electrically activating active sites on the catalyst particles. 
     
     
         9 . The method of  claim 8 , wherein electrically activating the active sites on the catalyst particles comprises synthesizing a reaction-enhancing compound at the active sites. 
     
     
         10 . The method of  claim 9 , wherein the reaction-enhancing compound comprises a metal oxyhydroxide. 
     
     
         11 . The method of  claim 8 , wherein electrochemically oxidizing the one or more precursor compounds to chemically convert the one or more precursor compounds to one or more catalyst compounds and electrically activating the active sites on the catalyst particles occur simultaneously or substantially simultaneously. 
     
     
         12 . The method of  claim 1 , wherein the one or more precursor compounds comprise one or more metal hydroxides. 
     
     
         13 . The method of  claim 1 , wherein the slurry comprises one or both of a thickener and a binder. 
     
     
         14 . The method of  claim 1 , wherein apply the slurry to the one or more surfaces of the conductive substrate comprises at least one of: dip coating the conductive substrate with the slurry, painting the one or more surfaces of the conductive substrate with the slurry, spraying the slurry onto the one or more surfaces of the conductive substrate, applying the slurry onto one or more surfaces of the conducive substrate with a doctor blade, applying the slurry onto one or more surfaces of the conducive substrate with a slot die, and applying the slurry onto one or more surfaces of the conducive substrate with a comma bar. 
     
     
         15 . The method of  claim 1 , wherein the conductive substrate comprises a metal mesh. 
     
     
         16 . The method of  claim 1 , wherein the conductive substrate comprises one or more of: nickel metal, titanium metal, steel, gold metal, copper metal, and a conductive carbon-based material. 
     
     
         17 . The method of  claim 1 , further comprising:
 coprecipitating one or more precursor compounds from a precursor solution comprising one or more first metal salts and one or more second metal salts to produce precipitated precursor particles comprising the one or more precursor compounds; and   forming the slurry from the precipitated precursor particles and the slurry medium.   
     
     
         18 . The method of  claim 17 , further comprising washing the precipitated precursor particles before forming the slurry. 
     
     
         19 . The method of  claim 17 , wherein the one or more catalyst compounds comprise a spinel oxide having the general chemical formula AB 2 O 4 , wherein the one or more first metal salts comprise one or more first salts of A, and wherein the one or more second metal salts comprises one or more second salts of B. 
     
     
         20 . The method of  claim 19 , wherein the one or more first salts and the one or more second salts each comprise at least one of: a metal nitrate, a metal acetate, a metal sulfate, or a metal halide. 
     
     
         21 . The method of  claim 20 , wherein the one or more first salts are different from each of the one or more second salts.