Electrocatalyst for oxygen evolution reactions

Abstract

An example electrochemical system includes: a cathode including a first electrocatalyst configured to catalyze a reduction reaction of carbon dioxide to produce water; an anode including a second electrocatalyst comprising ruthenium doped iridium oxide, the second electrocatalyst configured to catalyze an oxygen evolution reaction to produce diatomic oxygen from the water; an electrolyte connecting the cathode and the anode; and an electricity source configured to apply an electrical current across the cathode and the anode to catalyze the reduction and oxygen evolution reactions.

1 . An electrochemical system comprising:
 a cathode including a first electrocatalyst configured to catalyze a reduction reaction of carbon dioxide to produce water;   an anode including a second electrocatalyst comprising ruthenium doped iridium oxide, the second electrocatalyst configured to catalyze an oxygen evolution reaction to produce diatomic oxygen from the water;   an electrolyte connecting the cathode and the anode; and   an electricity source configured to apply an electrical current across the cathode and the anode to catalyze the reduction and oxygen evolution reactions.   
     
     
         2 . The electrochemical system of  claim 1 , wherein the ruthenium is doped into the iridium oxide in a solution having a ruthenium concentration of between about 0.05 mg mL-1 to about 1 mg mL −1 . 
     
     
         3 . The electrochemical system of  claim 2 , wherein the ruthenium concentration of the solution is about 1 mg mL −1 . 
     
     
         4 . The electrochemical system of  claim 2 , wherein the solution comprises ruthenium chloride (RuCl 3 ) in ethylene glycol. 
     
     
         5 . The electrochemical system of  claim 2 , wherein the ruthenium is doped in an amount of less than 1% by weight. 
     
     
         6 . The electrochemical system of  claim 1 , wherein the electricity source is configured to apply the electrical current at a current density of between about 200 mA cm −1  to about 500 mA cm −1 . 
     
     
         7 . The electrochemical system of  claim 1 , wherein the electrolyte comprises a neutral electrolyte. 
     
     
         8 . The electrochemical system of  claim 5 , wherein the electrolyte comprises KCO 3 . 
     
     
         9 . The electrochemical system of  claim 1 , wherein the cathode comprises a silver gas diffusion electrode. 
     
     
         10 . A method comprising:
 providing an electrochemical system comprising:
 a cathode including a first electrocatalyst; 
 an anode including a second electrocatalyst comprising ruthenium (Ru) doped iridium oxide (IrO x ); 
 an electrolyte connecting the cathode and the anode; and 
 an electricity source configured to apply an electrical current across the cathode and the anode; 
   providing carbon dioxide at the cathode; and   applying, via the electricity source, the electrical current to the electrochemical system, and in response:
 catalyzing, at the cathode, a reduction reaction of the carbon dioxide to produce water; and 
 catalyzing, at the anode, an oxygen evolution reaction to produce diatomic oxygen from the water. 
   
     
     
         11 . The method of  claim 10 , further comprising preparing the second electrocatalyst by doping the ruthenium into the iridium oxide. 
     
     
         12 . The method of  claim 11 , wherein preparing the second electrocatalyst comprises:
 preparing an IrO x /Ti electrode via anodic electrodeposition;   preparing a solution of ruthenium chloride (RuCl 3 ) with ethylene glycol as a solvent;   synthesizing the Ru/IrO x  by immersing the IrO x /Ti electrode in the solution to drive a galvanic replacement reaction.   
     
     
         13 . The method of  claim 12 , wherein the solution has a ruthenium concentration of between 0.05 mg mL −1  to about 1 mg mL −1 . 
     
     
         14 . The method of  claim 10 , comprising applying the electrical current at a current density of between about 200 mA cm −1  to about 500 mA cm −1 . 
     
     
         15 . The method of  claim 14 , comprising applying the electrical current at the current density of about 200 mA cm −1  for at least 200 hours. 
     
     
         16 . The method of  claim 15 , comprising applying the electrical current at the current density of about 200 mA cm −1  for at least 400 hours. 
     
     
         17 . The method of  claim 14 , comprising applying the electrical current at the current density of about 500 mA cm −1  for at least 100 hours. 
     
     
         18 . The method of  claim 10 , wherein the electrolyte comprises a neutral electrolyte. 
     
     
         19 . A catalyst for an oxygen evolution reaction comprising ruthenium (Ru) doped iridium oxide (IrO x ). 
     
     
         20 . The catalyst of  claim 19 , wherein the ruthenium is doped into the iridium oxide in a solution having a ruthenium concentration of between about 0.05 mg mL −1  to about 1 mg mL −1 .