Cell

Abstract

An electrolytic cell comprising an anode in an anode region and a cathode in a cathode region, the anode region and the cathode regions separated by an ion selective polymer electrolyte membrane; an anolyte in flowing fluid communication with the anode, the anolyte comprising water and a redox mediator couple which is at least partially oxidised at the anode in operation of the cell and at least partially reduced by reaction with water after such oxidation at the anode.

1 . An electrolytic cell comprising an anode in an anode region and a cathode in a cathode region, the anode region and the cathode regions separated by an ion selective polymer electrolyte membrane; an anolyte in flowing fluid communication with the anode, the anolyte comprising water and a redox mediator couple which is at least partially oxidised at the anode in operation of the cell and at least partially reduced by reaction with water after such oxidation at the anode, the reaction being driven forward by a catalyst comprised in the anode region. 
     
     
         2 . The electrolytic cell of  claim 1 , wherein the catalyst is provided on the surface of the anode and/or the membrane. 
     
     
         3 . The electrolytic cell of  claim 1 , wherein the catalyst is provided in a fixed bed in the anolyte channel. 
     
     
         4 . The electrolytic cell of  claim 1 , wherein the catalyst is dissolved or suspended in the anolyte. 
     
     
         5 . The electrolytic cell of  claim 1 , wherein the catalyst comprises one or more atoms of a group 6 to 9 transition metal. 
     
     
         6 . The electrolytic cell of  claim 5 , wherein the group 6 to 9 transition metal is manganese, osmium, rhodium, ruthenium, tungsten, and/or iridium. 
     
     
         7 . The electrolytic cell of  claim 1 , wherein the redox mediator couple has a redox potential greater than 1.25V. 
     
     
         8 . The electrolytic cell of  claim 1 , wherein the redox mediator couple has a redox potential of 1.3V to 1.8V. 
     
     
         9 . The electrolytic cell of  claim 1 , wherein the redox mediator couple comprises cerium. 
     
     
         10 . The electrolytic cell of  claim 1 , wherein the anode region is provided with a separation zone to remove at least some oxygen gas from the anolyte. 
     
     
         11 . The electrolytic cell of  claim 10 , wherein the separation zone comprises cavitation means to effect the separation of the gas and liquid phases. 
     
     
         12 . The electrolytic cell of  claim 10 , wherein the separation zone further comprises an oxygen gas outlet. 
     
     
         13 . The electrolytic cell of  claim 12 , further comprising condensers and/or demisters may be provided upstream, in or downstream of the oxygen gas outlet. 
     
     
         14 . The electrolytic cell of  claim 1 , wherein the anode is non-porous, partially porous or porous. 
     
     
         15 . The electrolytic cell of  claim 1 , wherein the anode is a composite electrode. 
     
     
         16 . A method of operating an electrolytic cell comprising:
 a) providing an anode in an anode region and a cathode in a cathode region of the electrolytic cell, the anode region and the cathode regions separated by an ion selective polymer electrolyte membrane;   b) providing an anolyte comprising water and a redox mediator couple   c) contacting the anolyte with the anode, causing the anolyte to be at least partially oxidised at the anode and at least partially reduced by reaction with water after such oxidation at the anode, the reaction being driven forwardly by a catalyst comprised in the anode region.