Conversion of Carbon Dioxide to Organic Products

Abstract

The invention relates to various embodiments of an environmentally beneficial method for reducing carbon dioxide. The methods in accordance with the invention include electrochemically or photoelectrochemically reducing the carbon dioxide in a divided electrochemical cell that includes an anode, e.g., an inert metal counterelectrode, in one cell compartment and a metal or p-type semiconductor cathode electrode in another cell compartment that also contains an aqueous solution of an electrolyte and a catalyst of one or more substituted or unsubstituted aromatic amines to produce therein a reduced organic product.

1 - 16 . (canceled) 
     
     
         17 . A system for electrochemical or photoelectrochemical reduction of carbon dioxide to produce at least one product, comprising:
 an electrochemical cell including a first compartment containing an anode, and a second compartment having a cathode which is a metal or p-type semiconductor, and a catalyst which is a substituted or unsubstituted aromatic heterocyclic amine; both compartments containing an aqueous electrolytes   a source for providing carbon dioxide to the cathode; and   an energy source supplied to the cell to reduce the carbon dioxide,   
     
     
         18 . The system of  claim 17 , wherein the metal is Au, Ag, Zn, Ga, Hg, In, Cd, Ti, Pd or Pt. 
     
     
         19 . The system of  claim 18 , wherein the cathode is Pt or hydrogenated Pd. 
     
     
         20 . The system of  claim 17 , wherein the reduction is photoelectrochemical and the cathode is a p-type semiconductor responsive to illumination. 
     
     
         21 . The system of  claim 20 , wherein the semiconductor is p-GaP, p-GaAs, p-InP, p-InN, p-WSe 2 , p-CdTe, p-GaInP 2  or p-Si. 
     
     
         22 . The system of  claim 17 , wherein energy is provided to the cell by illuminating the cathode with light energy. 
     
     
         23 . The system of  claim 17 , wherein the light energy is converted to electrical energy. 
     
     
         24 . The system of  claim 17 , wherein the substituted or unsubstituted aromatic heterocyclic amine is represented by formula 1: 
       
         
           
           
               
               
           
         
         wherein the ring structure W is an aromatic 5- or 6-member heterocyclic ring with at least one ring nitrogen and is optionally substituted at one or more ring positions other than nitrogen with R, and wherein L is C or N, R 1  is H, R 2  is H if L is N or R 2  is R if L is C, and R is an optional substituent on any ring carbon and is independently selected from H, straight chain or branched chain lower alkyl, hydroxyl, amino, pyridyl, or two R's taken together with the ring carbons to which they are bonded are a fused six-member aryl ring, and n=0 to 4. 
       
     
     
         25 . The system of  claim 17 , wherein the substituted or unsubstituted aromatic heterocyclic amine is a lower alkyl substituted pyridine, a lower alkyl amino substituted pyridine, an unsubstituted bipyridine, a lower alkyl substituted bipyridine, a hydroxy-pyridine, hydroxy-bipyridine, lower alkyl amino substituted bipyridine, an unsubstituted or substituted quinoline or isoquinoline, an unsubstituted or substituted imidazole or benzimidazole, a dialkylated imidazolium, or a substituted or unsubstituted pyrrole. 
     
     
         26 . The system of  claim 17 , where the at least one product is methanol, isopropanol, formic acid, formaldehyde, glyoxal or ethanol. 
     
     
         27 - 29 . (canceled)