Electrode system for reducing carbon dioxide

Abstract

A method of electrochemically reducing CO2 to form at least one alcohol, preferably ethanol. The method includes (a) contacting an electrode system with an aqueous solution comprising at least one electrolyte and CO2, wherein the electrode system comprises a working electrode, a counter electrode, and a reference electrode, wherein the working electrode comprises a base electrode and a coating of a composite comprising graphene nanosheets and Cu2O nanoparticles disposed on a surface of the base electrode, and (b) applying a negative potential to the working electrode to reduce the CO2 and form the at least one alcohol.

1 - 15 . (canceled) 
     
     
         16 : An electrode system, comprising:
 (a) a working electrode comprising a base electrode and a coating of a composite comprising graphene nanosheets and Cu 2 O nanoparticles disposed on a surface of the base electrode,   wherein the composite has a weight ratio of the graphene nanosheets:the Cu 2 O nanoparticles in the range of 0.2-0.8,   (b) a counter electrode, and   (c) a reference electrode.   
     
     
         17 : The electrode system of  claim 16 , wherein the Cu 2 O nanoparticles have an average particle size of 20-50 nm. 
     
     
         18 : The electrode system of  claim 16 , wherein the Cu 2 O nanoparticles are disposed on a surface of the graphene nanosheets in the composite. 
     
     
         19 : The electrode system of  claim 16 , wherein an amount of the coating of the composite disposed on the surface of the base electrode is 0.01-0.5 mg/cm 2  surface area of the base electrode. 
     
     
         20 : A method of making the working electrode of the electrode system of  claim 16 , the method comprising:
 (a) reacting graphene oxide with at least one Cu 2+  salt in the presence of at least one hydroxylamine, and/or at least one salt of hydroxylamine, and/or at least one substituted derivative of hydroxylamine and at least one surfactant in an alkaline aqueous solution to form a precipitate comprising the composite comprising graphene nanosheets and Cu 2 O nanoparticles,   (b) suspending the precipitate in a dispersing media to form a dispersion comprising the composite,   (c) depositing the dispersion on the surface of the base electrode to form a wet coating of the composite, and   (d) drying the wet coating of the composite to form the coating of the composite comprising graphene nanosheets and Cu 2 O nanoparticles disposed on the surface of the base electrode.