Catalysts for low temperature electrolytic co reduction

Abstract

A method for electrochemically reducing CO is provided. A cathode is provided, wherein the cathode comprises a conductive substrate with a catalyst of a metal and a metal oxide based coating on a side of the cathode. An anode is spaced apart from the cathode. An ionic transport is provided between the anode and cathode. The cathode is exposed to CO and H 2 O. The anode is exposed to H 2 O. A voltage is provided between the cathode and anode.

What is claimed is: 
     
         1 . A method for electrochemically reducing CO, comprising:
 providing a cathode, wherein the cathode comprises a conductive substrate with a catalyst of a metal and a metal oxide based coating on a side of the cathode;   providing an anode spaced apart from the cathode;   providing an ionic transport between the anode and cathode;   exposing the cathode to CO and H 2 O;   exposing the anode to H 2 O; and   providing a voltage between the cathode and anode.   
     
     
         2 . The method, as recited in  claim 1 , wherein the metal oxide is copper oxide. 
     
     
         3 . The method, as recited in  claim 2 , wherein the metal oxide is thicker than the native oxide. 
     
     
         4 . The method, as recited in  claim 3 , wherein the providing the cathode comprises:
 providing a conductive substrate with a metal coating; and   providing on the conductive substrate a metal oxide coating that is thicker than a native oxide layer by either annealing the metal coating, electrochemically oxidizing the metal coating, chemically oxidizing the metal coating or depositing a metal oxide layer.   
     
     
         5 . The method, as recited in  claim 4 , further comprising reducing metal oxide in the metal and metal oxide based coating to the metal 0 oxidation state. 
     
     
         6 . The method, as recited in  claim 5 , where the metal oxide in the metal and metal oxide based coating has a thickness that is greater than 50 nm. 
     
     
         7 . The method, as recited in  claim 1 , wherein the metal oxide and metal are of the same metal material. 
     
     
         8 . The method, as recited in  claim 1 , wherein the metal and metal oxide containing coating provide a metal and metal oxide interface. 
     
     
         9 . The method, as recited in  claim 1 , wherein the exposing the cathode to CO and H 2 O, comprises:
 exposing a first side of the cathode to H 2 O; and   flowing CO past a second side of the cathode.   
     
     
         10 . The method, as recited in  claim 1 , wherein the providing the cathode, comprises:
 providing a conductive substrate with a metal coating; and   applying an anodic square wave potential to the metal coating to form an oxide layer.   
     
     
         11 . The method, as recited in  claim 1 , wherein the metal coating is copper or copper alloy. 
     
     
         12 . The method, as recited in  claim 1 , wherein the ionic transport is an aqueous basic solution. 
     
     
         13 . A method for electrochemically reducing CO, comprising:
 providing on a cathode a coating formed by heating a metal layer of the cathode in air, electrochemically oxidizing the metal layer of the cathode, chemically oxidizing the metal layer or by a metal oxide deposition to form a metal and metal oxide interface;   providing an anode spaced apart from the cathode;   providing an ionic transport between the anode and cathode;   exposing the coating to CO and H 2 O;   exposing the anode to H 2 O; and   providing a voltage between the cathode and anode.   
     
     
         14 . The method, as recited in  claim 13 , wherein the cathode is copper and the coating is formed by heating the cathode to a temperature of at least 500° C. for at least 15 minutes. 
     
     
         15 . The method, as recited in  claim 13 , wherein the cathode is copper and the coating is formed by heating the cathode to a temperature of at least 300° C. for at least 15 minutes. 
     
     
         16 . The method, as recited in  claim 13 , further comprising reducing the metal oxide to metal. 
     
     
         17 . The method, as recited in  claim 13 , where the metal oxide has a thickness that is greater than 50 nm. 
     
     
         18 . The method, as recited in  claim 13 , where the metal oxide has a thickness that is greater than twice a thickness of a native oxide layer. 
     
     
         19 . The method, as recited in  claim 13 , wherein the providing on a cathode a coating, comprises applying an anodic square wave potential to the metal layer to form an oxide layer. 
     
     
         20 . The method, as recited in  claim 13 , wherein the metal layer is copper or copper alloy. 
     
     
         21 . The method, as recited in  claim 13 , wherein the metal oxide is copper oxide. 
     
     
         22 . The method, as recited in  claim 13 , wherein the ionic transport is an aqueous basic solution. 
     
     
         23 . An apparatus, for electrochemically reducing CO, comprising:
 an anode;   an oxidized cathode spaced apart from the anode;   a chamber for exposing the anode and oxidized cathode to at least one electrolyte adjacent to the anode and oxidized cathode;   a gas chamber for exposing the oxidized cathode to CO adjacent to the oxidized cathode; and   a CO source for providing CO to the gas chamber, connected to the gas chamber.   
     
     
         24 . The apparatus, as recited in  claim 23 , wherein the oxidized cathode comprises:
 a conductive substrate; and   an oxidized layer over the conductive substrate.   
     
     
         25 . The apparatus, as recited in  claim 24 , wherein the oxidized layer, comprises:
 a metal layer formed over the conductive substrate; and   a metal oxide layer formed over the conductive substrate and forming a metal layer metal oxide layer interface.   
     
     
         26 . The apparatus, as recited in  claim 25 , wherein the oxidized layer is subsequently reduced. 
     
     
         27 . The apparatus, as recited in  claim 23 , wherein the oxidized cathode comprises a metal layer that has been oxidized using an anodic square wave potential. 
     
     
         28 . The apparatus, as recited in  claim 23 , wherein the metal layer is copper or copper alloy. 
     
     
         29 . The apparatus, as recited in  claim 23 , wherein the metal oxide layer is copper oxide.