Carbon dioxide electrolysis operation mode

Abstract

A CO2RR and a CO2RR electrochemical cell (2) is provided, comprising a three-phase boundary (14) having: a gaseous CO2 diffused at least partially through a porous cathode (8), a solid catalyst (10) operatively associated with the cathode 8, and a catholyte (12) or membrane (16) in communication with the catalyst (10); a pressure controller (30) adapted to control back pressure within, at or near the three-phase boundary (14); and a reaction product of the CO2RR selected from the group consisting of: hydrocarbon, alcohol, H2 and CO.

What is claimed is: 
     
         1 . A CO 2 RR, comprising:
 a three-phase boundary ( 14 ) comprising:
 a gaseous CO 2  diffused at least partially through a porous cathode ( 8 ), 
 a solid catalyst ( 10 ) operatively associated with the cathode ( 8 ), and 
 a liquid catholyte ( 12 ) or a membrane ( 16 ) in communication with the catalyst ( 10 ); 
   a pressure controller ( 30 ) that controls pressure within the three-phase boundary ( 14 ) in order to increase a dwell time of the CO 2 RR within the three-phase boundary ( 14 ); and   a reaction product of the CO 2 RR formed within the three-phase boundary ( 14 ) selected from the group consisting of: hydrocarbon, alcohol, H 2  and CO.   
     
     
         2 . The CO 2 RR of  claim 1 , further comprising pressure sensors ( 24 ) and ( 26 ) arranged within the three-phase boundary ( 14 ) to detect back pressure within the three-phase boundary ( 14 ). 
     
     
         3 . The CO 2 RR of  claim 2 , wherein the pressure controller ( 30 ) controls back pressure detected by the pressure sensors ( 24 ) and ( 26 ) between 0 mbar-400 mbar. 
     
     
         4 . The CO 2 RR of  claim 3 , wherein the cathode ( 8 ) is a gas diffusion electrode. 
     
     
         5 . The CO 2 RR of  claim 4 , wherein a catalyst ( 10 ) is selected from the group consisting of Cu, Ag, Au, Pd and Sn and the catalyst  10  is adhered to the cathode ( 8 ) by drop casting, plating, spray-coating or doping. 
     
     
         6 . The CO 2 RR of  claim 5 , wherein the catholyte ( 12 ) is an alkaline buffer liquid solution comprising potassium hydrogen carbonate, cesium hydrogen carbonate, rubidium hydrogen carbonate, lithium bicarbonate or potassium hydroxide, and the liquid catholyte is in fluid communication with the catalyst ( 10 ). 
     
     
         7 . The CO 2 RR of  claim 5 , wherein the catholyte ( 12 ) is either: (i) an alkaline buffer liquid solution comprising potassium hydrogen carbonate, cesium hydrogen carbonate, rubidium hydrogen carbonate, lithium bicarbonate or potassium hydroxide, or (ii) a solid polymer, and wherein the membrane ( 16 ) is either an anion exchange membrane or a bipolar membrane. 
     
     
         8 . The CO 2 RR of  claim 7 , wherein the reaction product includes ethene. 
     
     
         9 . The CO 2 RR of  claim 8 , further comprising an outlet pressure sensor ( 26 ) arranged within an outlet ( 22 ). 
     
     
         10 . CO 2 RR of  claim 1 , wherein the CO 2 RR occurs in an electrochemical cell ( 2 ) having an inlet ( 4 ) through which the CO 2  enters the electrochemical cell ( 2 ) and having an outlet ( 22 ) through which the reaction product exits the electrochemical cell ( 2 ). 
     
     
         11 . The CO 2 RR of  claim 10 , wherein the electrochemical cell further comprises a membrane ( 16 ) that separates the cathode ( 8 ) from an anode ( 20 ) to prevent short circuiting of the electrochemical cell ( 2 ) while allowing cations to circulate between the liquid catholyte ( 12 ) and a liquid anolyte ( 18 ). 
     
     
         12 . A CO 2 RR electrochemical cell ( 2 ), comprising:
 an inlet ( 4 ) through which gaseous CO 2  enters the electrochemical cell ( 2 ) and advances into a chamber ( 6 );   a porous cathode ( 8 ) through which the gaseous CO 2  in the chamber ( 6 ) can at least partially diffuse through;   a solid catalyst ( 10 ) adhered to the cathode ( 8 );   a liquid catholyte ( 12 ) in fluid communication with the solid catalyst ( 10 ), wherein the gaseous CO 2  contained in the porous cathode ( 8 ) and the solid catalyst ( 10 ) and the liquid catholyte ( 12 ) collectively form a three-phase boundary ( 14 );   a membrane ( 16 ) that separates the cathode ( 8 ) from an anode ( 20 ) to prevent short circuiting of the electrochemical cell ( 2 ) while allowing cations to circulate between the liquid catholyte ( 12 ) and a liquid anolyte ( 18 );   an outlet ( 22 ) through which a hydrocarbon reaction product of the CO 2 RR exits the electrochemical cell ( 2 );   pressure sensors ( 24 ) and ( 26 ) arranged near the three-phase boundary ( 14 ) to detect back pressure within the three-phase boundary ( 14 ); and   a pressure controller ( 30 ) adapted to adjust the back pressure detected by the pressure sensors ( 24 ) and ( 26 ) between 0 mbar-400 mbar in order to increase a dwell time of the CO 2 RR within the three-phase boundary ( 14 );   
     
     
         13 . The CO 2 RR electrochemical cell ( 2 ) of  claim 12  further comprising an inlet pressure sensor ( 28 ) arranged near the inlet ( 4 ), and further comprising a second pressure controller ( 32 ) arranged near the inlet ( 4 ) upstream the inlet pressure sensor ( 28 ), and wherein the reaction product is a hydrocarbon, alcohol, H 2  and/or CO.