Materials and methods for the electrochemical reduction of carbon dioxide

Abstract

Disclosed are methods for electrochemically reducing carbon dioxide to provide a product. The methods can comprise contacting the carbon dioxide with an electroreduction catalyst in an electrochemical cell, and applying a potential to the eletrochemical ceil to form the product. The electroreduction catalyst can comprise a nanoporous Cu catalyst, a nanoporous Cu-M catalyst, or a combination thereof, where M is a metal chosen from Pt, Ir, Pd, Ag, Au, Rh, Ru, Zn, Sn, Ni, Fe, Re, Ga, In, Cd, Tl, and Ti. The product can comprise a C 2 -C 3 alkane, a C 2 -C 3 alkene, a C 2 -C 3 alcohol, a C 2 -C 3 carboxylic acid, a C 2 -C 3 aldehyde, or a combination thereof.

What is claimed is: 
     
         1 . A method for electrochemically reducing carbon dioxide to provide a product, the method comprising contacting the carbon dioxide with an electroreduction catalyst in an electrochemical cell, and applying a potential to the electrochemical cell to form the product,
 wherein the electroreduction catalyst comprises a nanoporous Cu catalyst, a nanoporous Cu-M catalyst, or a combination thereof, where M is a metal chosen from Pt, Ir, Pd, Ag, Au, Rh, Ru, Zn, Sn, Ni, Fe, Re, Ga, In, Cd, Tl, and Ti; and   wherein the product comprises a C 2 -C 3  alkane, a C 2 -C 3  alkene, a C 2 -C 3  alcohol, a C 2 -C 3  carboxylic acid, a C 2 -C 3  aldehyde, or a combination thereof.   
     
     
         2 . The method of  claim 1 , wherein the electroreduction catalyst comprises nanoparticles having an average particle size of from 10 nm to 500 nm, as determined by scanning electron microscopy (SEM). 
     
     
         3 . The method of  claim 2 , wherein the nanoparticles have a BET surface area of from 10 m 2 /g to 40 m 2 /g. 
     
     
         4 . The method of any of  claims 1 - 3 , wherein the electroreduction catalyst comprises a nanoporous Cu-M catalyst where M is a metal chosen from Pt, Ir, Pd, Ag, Au, Rh, Ru, Zn, Ni, Fe, Re, Ga, In, Cd, Tl, and Ti. 
     
     
         5 . The method of  claim 4 , wherein the electroreduction catalyst comprises a nanoporous Cu—Ru catalyst. 
     
     
         6 . The method of any of  claims 1 - 5 , wherein the product comprises ethanol, propanol, or a combination thereof. 
     
     
         7 . The method of  claim 6 , wherein the wherein the product comprises propanol. 
     
     
         8 . The method of  claim 7 , wherein the propanol is formed at a Faradaic efficiency of from 0.5% to 15%. 
     
     
         9 . The method of any of  claims 1 - 8 , wherein the method is selective for the formation of C 2 -C 3  over methanol, such that the C 2 -C 3  alcohols are formed with at least 10 times greater Faradaic efficiency than methanol. 
     
     
         10 . The method of any of  claims 1 - 9 , wherein the product comprises ethane, ethylene, or a combination thereof. 
     
     
         11 . The method of any of  claims 1 - 10 , wherein the method is selective for the formation of C 2 -C 3  alkanes over methane, such that the C 2 -C 3  alkanes are formed with at least 10 times greater Faradaic efficiency than methane. 
     
     
         12 . The method of any of  claims 1 - 11 , wherein the electrochemical cell is a divided electrochemical cell comprising
 a working electrode comprising the electroreduction catalyst in a first cell compartment, a counter electrode in a second cell compartment, and a solid electrolyte membrane interposed between the working electrode and the counter electrode, both the first cell compartment and the second cell compartment further comprising an aqueous solution of an electrolyte;   wherein contacting the carbon dioxide with the electroreduction catalyst comprises introducing the carbon dioxide into the first cell compartment of the divided electrochemical cell; and   wherein applying a potential to the electrochemical cell comprises applying a negative voltage and a positive voltage to the working electrode and the counter electrode, respectively, to reduce the carbon dioxide to form the product.   
     
     
         13 . The method of  claim 12 , wherein the electrolyte comprises an alkali metal bicarbonate. 
     
     
         14 . The method of  claim 13 , wherein the alkali metal bicarbonate is potassium bicarbonate. 
     
     
         15 . The method of any of  claims 1 - 14 , wherein the applied potential is from −0.15 V to −1.8 V vs. a reversible hydrogen electrode. 
     
     
         16 . An electrochemical cell for electrochemically reducing carbon dioxide to provide a product, the electrochemical cell comprising
 a working electrode comprising an electroreduction catalyst in a first cell compartment, wherein the electroreduction catalyst comprises a nanoporous Cu catalyst, a nanoporous Cu-M catalyst, or a combination thereof, where is a metal chosen from Pt, Ir, Pd, Ag, Au, Rh, Ru, Zn, Sn, Ni, Fe, Re, Ga, In, Cd, Tl, and Ti;   a counter electrode in a second cell compartment; and   a solid electrolyte membrane interposed between the working electrode and the counter electrode;   both the first cell compartment and the second cell compartment further comprising an aqueous solution of an electrolyte.   
     
     
         17 . The cell of  claim 16 , wherein the electroreduction catalyst comprises a nanoporous Cu-M catalyst where M is a metal chosen from Pt, Ir, Pd, Ag, Au, Rh, Ru, Zn, Ni, Fe, Re, Ga, In, Cd, Tl, and Ti. 
     
     
         18 . The cell of  claim 17 , wherein the electroreduction catalyst comprises a nanoporous Cu—Ru catalyst 
     
     
         19 . A method for preparing an organic compound defined by Formula II from a carboxylic acid defined by Formula I and a carboxylic acid defined by Formula I′ according to the equation below 
       
         
           
             
               
                 
                   
                     
                       
                           
                       
                     
                   
                   
                     
                       RCOOH 
                     
                   
                   
                     
                       
                         Formula 
                          
                         
                             
                         
                          
                         I 
                       
                     
                   
                 
                 + 
                 
                   
                     
                       
                           
                       
                     
                   
                   
                     
                       
                         
                           R 
                           ′ 
                         
                          
                         COOH 
                       
                     
                   
                   
                     
                       
                         Formula 
                          
                         
                             
                         
                          
                         
                           I 
                           ′ 
                         
                       
                     
                   
                 
                 + 
                 
                   1 
                    
                   
                     / 
                   
                    
                   2 
                    
                   
                       
                   
                    
                   
                     O 
                     2 
                   
                 
               
               → 
               
                 
                   
                     
                       
                           
                       
                     
                   
                   
                     
                       
                         R 
                          
                         
                           - 
                         
                          
                         
                           R 
                           ′ 
                         
                       
                     
                   
                   
                     
                       
                         Formula 
                          
                         
                             
                         
                          
                         II 
                       
                     
                   
                 
                 + 
                 
                   CO 
                   2 
                 
                 + 
                 
                   
                     H 
                     2 
                   
                    
                   O 
                 
               
             
           
         
         where R and R′ interdependently represent hydrogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkylaryl group, or a substituted or unsubstituted alkylheteroaryl group, the method comprising contacting the carboxylic acid defined by Formula I and the carboxylic acid defined by Formula I′ with an electroreduction catalyst in an electrochemical cell, and applying a potential to the electrochemical cell to form the organic compound defined by Formula II, 
         wherein the electroreduction catalyst comprises a nanoporous Cu catalyst, a nanoporous Cu-M catalyst, or a combination thereof, where M is a metal chosen from Pt, Ir, Pd, Ag, Au, Rh, Ru, Zn, Sn, Ni, Fe, Re, Ga, In, Cd, Tl, and Ti.