Gas diffusion anode and co2 cathode electrolyte system

Abstract

A low-voltage, low-energy electrochemical system and method of removing protons and/or producing a base solution using a gas diffusion anode and a cathode electrolyte comprising dissolved carbon dioxide, while applying 2V or less across the anode and cathode.

1 . An electrochemical system comprising:
 a gas diffusion anode; and   a cathode contacting a cathode electrolyte comprising dissolved carbon dioxide.   
     
     
         2 . The system of  claim 1 , further comprising a gas delivery system configured to deliver hydrogen gas to the anode. 
     
     
         3 . The system of  claim 2 , wherein the hydrogen gas is produced at the cathode. 
     
     
         4 . The system of  claim 2 , wherein the anode is configured to produce protons, and the cathode is configured to produce hydrogen gas and hydroxide ions on application of a voltage across the anode and the cathode. 
     
     
         5 . The system of  claim 4 , wherein the voltage is less than 2V. 
     
     
         6 . The system of  claim 4 , wherein the system is configured not to produce a gas at the anode. 
     
     
         7 . The system of  claim 4 , further comprising a first cation exchange membrane positioned between the cathode electrolyte and a salt solution, and an anion exchange membrane positioned between the salt solution and an anode electrolyte. 
     
     
         8 . The system of  claim 7 , wherein the anode contacts the anode electrolyte. 
     
     
         9 . The system of  claim 7 , wherein a second cation exchange membrane is positioned between the anode and the anode electrolyte. 
     
     
         10 . The system of  claim 9 , wherein the system is configured to migrate anions to the anode electrolyte from the salt solution through the anion exchange membrane. 
     
     
         11 . The system of  claim 9 , wherein the system is configured to migrate chloride ions to the anode electrolyte from the salt solution through the anion exchange membrane. 
     
     
         12 . The system of  claim 11 , wherein the system is configured to migrate cations to the cathode electrolyte from the salt solution through the first cation exchange membrane. 
     
     
         13 . The system of  claim 12 , wherein the system is configured to migrate sodium ions to the cathode electrolyte from the salt solution through the first cation exchange membrane. 
     
     
         14 . The system of  claim 9 , wherein the system is configured to migrate protons to the anode electrolyte from the anode. 
     
     
         15 . The system of  claim 14 , wherein the system is configured to migrate hydroxide ions to the cathode electrolyte from the cathode. 
     
     
         16 . The system of  claim 15 , wherein the system is configured to produce sodium hydroxide and/or sodium bicarbonate and/or sodium carbonate in the cathode electrolyte. 
     
     
         17 . The system of  claim 14 , wherein the system is configured to produce an acid in the anode electrolyte. 
     
     
         18 . The system of  claim 17 , wherein the system is configured to produce hydrochloric acid in the anode electrolyte. 
     
     
         19 . The system of  claim 9 , further comprising a partition that partitions the cathode electrolyte into a first cathode electrolyte portion and a second cathode electrolyte portion, wherein the second cathode electrolyte portion contacts the cathode and comprises dissolved carbon dioxide. 
     
     
         20 . The system of  claim 19 , wherein the first cathode electrolyte portion comprises gaseous carbon dioxide. 
     
     
         21 . The system of  claim 19 , wherein the partition is positioned to isolate gaseous carbon dioxide gas in the first cathode electrolyte portion from cathode electrolyte in the second cathode electrolyte portion. 
     
     
         22 . The system of  claim 21 , wherein the system is configured to produce hydroxide ions and hydrogen gas at the cathode. 
     
     
         23 . The system of  claim 22 , wherein the system is configured to produce hydroxide ions in the cathode electrolyte. 
     
     
         24 . The system of  claim 23 , wherein the system is configured to
 migrate cations to the cathode electrolyte through the first cation exchange membrane;   migrate anions to the anode electrolyte through the anion exchange membrane; and   migrate protons to the anode electrolyte from the anode.   
     
     
         25 . The system of  claim 24 , wherein the system is configured to produce cations, hydroxide ions and/or carbonic acid and/or carbonate ions and/or bicarbonate ions in the cathode electrolyte. 
     
     
         26 . The system of  claim 25 , wherein the system is configured to produce sodium hydroxide and/or sodium carbonate and/or sodium bicarbonate in the cathode electrolyte. 
     
     
         27 . The system of  claim 26 , wherein the cathode electrolyte is operatively connected to a carbon dioxide gas/liquid contactor configured to dissolve carbon dioxide in the cathode electrolyte. 
     
     
         28 . The system of  claim 27 , wherein the cathode electrolyte is operatively connected to a system configured to produce carbonates and/or bicarbonates and/or hydroxides from a solution comprising carbon dioxide and divalent cations. 
     
     
         29 . An electrochemical method comprising:
 applying a voltage across a cathode and a gas diffusion anode in an electrochemical system, wherein the cathode contacts a cathode electrolyte comprising dissolved carbon dioxide.   
     
     
         30 . The method of  claim 29 , comprising oxidizing hydrogen gas at the anode. 
     
     
         31 . The method of  claim 30 , comprising producing protons at the anode. 
     
     
         32 . The method of  claim 30 , comprising producing hydroxide ions and hydrogen gas at the cathode. 
     
     
         33 . The method of  claim 32 , wherein a gas is not produced at the anode. 
     
     
         34 . The method of  claim 32 , wherein the voltage is less than 2V. 
     
     
         35 . The method of  claim 32 , comprising directing hydrogen gas from the cathode to the anode. 
     
     
         36 . The method of  claim 31 , comprising migrating protons from the anode to an anode electrolyte. 
     
     
         37 . The method of  claim 34 , comprising interposing a cation exchange membrane between the anode and an anode electrolyte. 
     
     
         38 . The method of  claim 37 , comprising interposing an anion exchange membrane between the anode electrolyte and a salt solution. 
     
     
         39 . The method of  claim 38 , comprising interposing a first cation exchange membrane between the cathode electrolyte and the salt solution, and wherein the salt solution is disposed between the anion exchange membrane and the first cation exchange membrane. 
     
     
         40 . The method of  claim 39 , comprising migrating anions from the salt solution to the anode electrolyte through the anion exchange membrane, and migrating cations from the salt solution to the cathode electrolyte through the first cation exchange membrane. 
     
     
         41 . The system of  claim 40 , comprising producing hydroxide ions and/or carbonate ions and/or bicarbonate ions in the cathode electrolyte; and an acid in the anode electrolyte. 
     
     
         42 . The method of  claim 40 , comprising producing sodium hydroxide and/or sodium carbonate and/or sodium bicarbonate in the cathode electrolyte; and hydrochloric acid in the anode electrolyte. 
     
     
         43 . The method of  claim 42 , comprising contacting the cathode electrolyte with a divalent cation solution comprising calcium and/or magnesium ions. 
     
     
         44 . The method of  claim 42 , comprising producing partially desalinated water in the salt solution.