Anode for electrolysis and method of preparing the same

Abstract

Provided is an anode for electrolysis having reduced overvoltage and improved lifetime while exhibiting high efficiency, and a method of preparing the same. Because the anode for electrolysis is prepared by electrostatic spray deposition, an active material can be uniformly distributed in a catalyst layer, and thus, an overvoltage can be reduced and lifetime can be improved while exhibiting high efficiency.

1 . An anode for electrolysis, the anode comprising:
 a metal base; and   a catalyst layer comprising ruthenium oxide, iridium oxide, palladium oxide, and titanium oxide on at least one surface of the metal base,   wherein   when the catalyst layer is equally divided into a plurality of pixels, a uniform distribution of active material in the catalyst layer is achieved as indicated by a standard deviation of iridium compositions of the plurality of divided pixels of 0.35 mol % or less.   
     
     
         2 . The anode for electrolysis of  claim 1 , wherein the standard deviation of the iridium compositions is 0.2 mol % or less. 
     
     
         3 . The anode for electrolysis of  claim 1 , wherein the catalyst layer comprises 7.5 g or more of ruthenium metal component of the ruthenium oxide per unit area (m 2 ) of the catalyst layer. 
     
     
         4 . The anode for electrolysis of  claim 1 , wherein the catalyst layer comprises the ruthenium oxide, the iridium oxide, the titanium oxide, and the palladium oxide in a molar ratio of from 25:10:35:2 to 35:25:50:15 based on the metal components of the oxides. 
     
     
         5 . The anode for electrolysis of  claim 1 , wherein the catalyst layer comprises the palladium oxide in a molar ratio of 2 to 20 based on total moles of the ruthenium oxide, the iridium oxide, and the titanium oxide. 
     
     
         6 . The anode for electrolysis of  claim 1 , wherein the catalyst layer further comprises niobium oxide. 
     
     
         7 . An anode for electrolysis, the anode comprising:
 a metal base; and   a catalyst layer on at least one surface of the metal base,   wherein:   the catalyst layer comprises a platinum group oxide and titanium oxide, wherein the platinum group oxide comprises ruthenium oxide, iridium oxide, and palladium oxide,   a molar ratio of the platinum group oxide to the titanium oxide is in a range of 90:10 to 40:60,   a molar ratio of the ruthenium oxide to the iridium oxide is in a range of 90:10 to 50:50,   a molar ratio of the palladium oxide to the ruthenium oxide and the iridium oxide is in a range of 5:95 to 40:60,   when the catalyst layer is equally divided into a plurality of pixels, a uniform distribution of active material in the catalyst layer is achieved as indicated by a standard deviation of iridium compositions of the plurality of divided pixels of 0.35 mol % or less, and   the anode when used for brine electrolysis has reduced overvoltage and generates 8 g/l or more of hypochlorite.   
     
     
         8 . The anode for electrolysis of  claim 1 , wherein the metal base comprises titanium, tantalum, aluminum, hafnium, nickel, zirconium, molybdenum, tungsten, stainless steel, or an alloy thereof. 
     
     
         9 . A method of preparing the anode for electrolysis of  claim 1 , the method comprising:
 coating a composition for forming a catalyst layer comprising a ruthenium oxide precursor, an iridium oxide precursor, a palladium oxide precursor, and a titanium oxide precursor on at least one surface of a metal base,   wherein the coating is performed by electrostatic spray deposition in which an amount of the composition for forming a catalyst layer per spray and a spray rate are adjusted to be in ranges of 50 ml to 80 ml and 20 ml/min to 35 ml/min, respectively;   drying the coating; and   heat-treating the coating.   
     
     
         10 . The method of  claim 9 , wherein the preparation method further comprises performing a pretreatment of the metal base before coating with the composition for forming a catalyst layer,
 wherein the pretreatment comprises formation of irregularities on the surface of the metal base by a chemical etching, blasting, or thermal spraying.   
     
     
         11 . The method of  claim 9 , wherein the composition for forming a catalyst layer is prepared by dissolving the ruthenium oxide precursor, the iridium oxide precursor, the palladium oxide precursor, and the titanium oxide precursor in an alcohol solution. 
     
     
         12 . The method of  claim 9 , wherein the coating, drying, and heat-treating of the composition for forming a catalyst layer are sequentially repeated so that an amount of ruthenium metal component of the ruthenium oxide per unit area (m 2 ) of the metal base is 7.5 g or more. 
     
     
         13 . The method of  claim 9 , wherein the composition for forming a catalyst layer further comprises a niobium oxide precursor. 
     
     
         14 . The anode for electrolysis of  claim 7 , wherein the metal base comprises titanium, tantalum, aluminum, hafnium, nickel, zirconium, molybdenum, tungsten, stainless steel, or an alloy thereof.