System and method for electrochemical co2 reduction

Abstract

An electrochemical CO 2 reduction system includes a functionalized ionic liquid (IL) that generates ion-CO 2 adducts and a hydrogen bond donor (HBD) upon CO 2 absorption to modulate CO 2 reduction reaction (CO 2 RR) on a Cu cathode in a non-aqueous electrolyte.

Having described the invention, the following is claimed: 
     
         1 . An electrochemical CO 2  reduction system comprising a functionalized ionic liquid (IL) that generates ion-CO 2  adducts and a hydrogen bond donor (HBD) upon CO 2  absorption to modulate CO 2  reduction reaction (CO 2 RR) on a Cu cathode in a non-aqueous electrolyte. 
     
     
         2 . The electrochemical CO 2  reduction system of  claim 1 , further including an electrochemical cell, wherein the non-aqueous electrolyte and Cu cathode are provided in the electrochemical cell. 
     
     
         3 . The electrochemical CO 2  reduction system of  claim 1 , wherein the non-aqueous electrolyte includes the functionalized IL and HBD. 
     
     
         4 . The electrochemical CO 2  reduction system of  claim 1 , wherein the functionalized IL includes a bifunctional IL, the bifunctional IL including a cation, which enhances an electric field to stabilize CO 2  between the cation and Cu cathode surface and a CO 2  chemisorbing anion. 
     
     
         5 . The electrochemical CO 2  reduction system of  claim 1 , wherein the combination of the cation and anion produces the HBD. 
     
     
         6 . The electrochemical CO 2  reduction system of  claim 4 , wherein HBD is formed in situ by absorption of CO 2 . 
     
     
         7 . The electrochemical CO 2  reduction system of  claim 4 , wherein the bifunctional IL includes an imidazolium-based cation and a pyrrolide-based anion. 
     
     
         8 . The electrochemical CO 2  reduction system of  claim 4 , wherein the bifunctional IL includes 1-ethyl-3-methylimidazolium pyrrole-2-carbonitrile ([EMIM][2-CNpyr]). 
     
     
         9 . The electrochemical CO 2  reduction system of  claim 4 , wherein the non-aqueous electrolyte includes a non-aqueous diluent in which the bifunctional IL is dissolved, wherein the non-aqueous diluent minimizes mass transfer limitations of the bifunctional IL and increases the ionic conductivity of the non-aqueous electrolyte. 
     
     
         10 . The electrochemical CO 2  reduction system of  claim 9 , wherein the non-aqueous diluent includes acetonitrile or ethylene glycol. 
     
     
         11 . The electrochemical CO 2  reduction system of  claim 9 , wherein the non-aqueous electrolyte further includes a supporting electrolyte to maintain a stable ionic conductivity of non-aqueous electrolyte. 
     
     
         12 . The electrochemical CO 2  reduction system of  claim 9 , wherein the supporting electrolyte includes a quaternary ammonium salt. 
     
     
         13 . The electrochemical CO 2  reduction system of  claim 1 , further comprising a voltage source configured to apply a voltage overpotential to the Cu cathode and the non-aqueous electrolyte to implement an electrochemical CO 2 RR of CO 2  on the Cu cathode in the non-aqueous electrolyte. 
     
     
         14 . The electrochemical CO 2  reduction system of  claim 13 , wherein the applied voltage overpotential is effective to reduce CO 2  in the non-aqueous electrolyte to at least one of CO, CH 4 , C 2 H 4 , C 2 H 6 , formate, succinate, formaldehyde, or butane. 
     
     
         15 . A method for electrochemical CO 2  reduction, the method comprising:
 providing an electrochemical cell that includes a Cu cathode in contact with a non-aqueous electrolyte, wherein the non-aqueous electrolyte includes a bifunctional ionic liquid (IL) which generates ion-CO 2  adducts and a hydrogen bond donor (HBD) upon CO 2  absorption; and   applying an overpotential to the Cu cathode and the non-aqueous electrolyte to implement an electrochemical CO 2  reduction reaction (CO 2 RR) of CO 2  in the non-aqueous electrolyte.   
     
     
         16 . The method of  claim 15 , wherein the bifunctional IL includes a cation, which enhances an electric field to stabilize CO 2  between the cation and Cu cathode surface and a CO 2  chemisorbing anion. 
     
     
         17 . The method of  claim 16 , wherein the bifunctional IL includes 1-ethyl-3-methylimidazolium pyrrole-2-carbonitrile ([EMIM][2-CNpyr]). 
     
     
         18 . The method of  claim 17 , wherein the non-aqueous electrolyte includes a non-aqueous diluent in which the bifunctional IL is dissolved, wherein the non-aqueous diluent minimizes the mass transfer limitations of the bifunctional IL and increases the ionic conductivity of the non-aqueous electrolyte. 
     
     
         19 . The method of  claim 18 , wherein the non-aqueous diluent includes acetonitrile or ethylene glycol. 
     
     
         20 . The method of  claim 18 , wherein the non-aqueous electrolyte further includes a supporting electrolyte to maintain a stable ionic conductivity of non-aqueous electrolyte.