Methods for the electroreduction of carbon dioxide to value added chemicals

Abstract

The present disclosure provides a method of electroreducing carbon dioxide (CO2). The method of electroreducing carbon dioxide may include feeding a first stream comprising carbon dioxide into a chamber through a chamber inlet, the chamber containing a gas diffusion cathode and a gas diffusion anode; feeding a second stream comprising glycerol or glucose into the chamber, the second stream having a pH of 12 to 14; and applying an electrical potential between the gas diffusion anode and the gas diffusion cathode to reduce the carbon dioxide and oxidize the glycerol or glucose.

1 . A method of electroreducing carbon dioxide, comprising:
 feeding a first stream comprising carbon dioxide into a chamber through a chamber inlet, the chamber containing a gas diffusion cathode and a gas diffusion anode;   feeding a second stream comprising glycerol or glucose into the chamber, the second stream having a pH of 12 to 14; and   applying an electrical potential between the gas diffusion anode and the gas diffusion cathode to reduce the carbon dioxide and oxidize the glycerol or glucose.   
     
     
         2 . The method of  claim 1 , further comprising withdrawing a liquid product stream from an outlet of the chamber, the liquid product stream comprising an oxidation product of glycerol or glucose or a reduction product of carbon dioxide and withdrawing a gaseous product stream comprising a reduction product of carbon dioxide selected from carbon monoxide, ethylene, methane, and any combination thereof. 
     
     
         3 . The method of  claim 2 , further comprising:
 a) purifying the liquid product stream to obtain a substantially pure stream of the oxidation product of glycerol or glucose or the reduction product of carbon dioxide; or   b) purifying the gaseous product stream to obtain a substantially pure stream of the reduction product of carbon dioxide.   
     
     
         4 . The method of  claim 1 , wherein the gas diffusion cathode divides the chamber into a gaseous region and a liquid region. 
     
     
         5 . The method of  claim 1 , wherein the second stream comprises from 0.5 M to 2.5 M of an alkali metal hydroxide. 
     
     
         6 . The method of  claim 1 , wherein the carbon dioxide is reduced to carbon monoxide, and wherein a partial current density for carbon monoxide is from 15 mA cm −2  to 350 mA cm −2  at a cell potential of −1.0 V to −2.5 V. 
     
     
         7 . The method of  claim 1 , wherein the carbon dioxide is reduced to a reduction product of carbon dioxide and an onset cell potential for formation of the reduction product of carbon dioxide is from −1.5 V to −0.5 V. 
     
     
         8 . The method of  claim 1 , wherein the chamber is divided into a cathode compartment and an anode compartment by an ion permeable membrane. 
     
     
         9 . The method of  claim 8 , wherein the second stream comprises an anolyte stream and a catholyte stream, wherein the anolyte stream is fed into the anode compartment and the catholyte stream is fed into the cathode compartment. 
     
     
         10 . The method of  claim 9 , wherein the anolyte stream comprises an alkali metal hydroxide or an alkali metal carbonate. 
     
     
         11 . The method of  claim 1 , wherein the gas diffusion cathode comprises an electrocatalytic cathode coating configured for reducing carbon dioxide. 
     
     
         12 . The method of  claim 11 , wherein the electrocatalytic cathode coating comprises a metal selected from silver, gold, zinc, palladium, tin, lead, mercury, indium, copper, and any combination thereof. 
     
     
         13 . The method of  claim 1 , wherein the gas diffusion anode comprises an electrocatalytic anode coating configured for oxidizing glycerol. 
     
     
         14 . The method of  claim 13 , wherein the electrocatalytic anode coating comprises a platinum black catalyst. 
     
     
         15 . The method of  claim 1 , wherein the chamber further comprises an ion permeable membrane in contact with the gas diffusion cathode. 
     
     
         16 . The method of  claim 1 , further comprising reducing the carbon dioxide to ethanol, formate, or any combination thereof. 
     
     
         17 . The method of  claim 1 , wherein the chamber is defined inside a flow electrolyzer. 
     
     
         18 . The method of  claim 1 , wherein the pH of the second stream is 12.5 to 14. 
     
     
         19 . A method of electroreducing carbon dioxide, comprising:
 feeding a gas stream comprising carbon dioxide into chamber divided into a cathode compartment and an anode compartment by an ion permeable membrane, the anode compartment containing a gas diffusion anode and the cathode compartment containing a gas diffusion cathode, the gas diffusion cathode dividing the cathode compartment into a gaseous region and a liquid region, wherein the gas stream is fed into the gaseous region;   feeding a catholyte stream into the liquid region of the cathode compartment;   feeding an anolyte stream comprising glycerol into the anode compartment to contact the gas diffusion anode; and   applying an electrical potential between the gas diffusion anode and the gas diffusion cathode to reduce the carbon dioxide to a reduction product and oxidize the glycerol to an oxidation product,   wherein an onset cell potential for formation of the reduction product is from −1.5 V to −0.5 V.   
     
     
         20 . The method of  claim 19 , wherein the catholyte stream or the anolyte stream has a pH from 13 to 14.