Oxidation electrode and electrochemical reaction device using the same

Abstract

An oxidation electrode in an embodiment includes: a conductive substrate made of a metal material including titanium, titanium alloy, or stainless steel; and an oxidation catalyst layer provided on the conductive substrate and made of a composite body containing nickel and iron. A bonding state of nickel and iron in the composite body containing nickel and iron is composed of Ni(OH)2, NiOOH, and FeOOH.

What is claimed is: 
     
         1 . An oxidation electrode comprising:
 a conductive substrate made of a metal material including titanium, titanium alloy, or stainless steel; and   an oxidation catalyst layer provided on the conductive substrate and made of a composite body containing nickel and iron, wherein   a bonding state of nickel and iron in the composite body is composed of Ni(OH) 2 , NiOOH, and FeOOH.   
     
     
         2 . The electrode according to  claim 1 , wherein
 a content of iron in the composite body is 20 mass % or more and 70 mass % or less.   
     
     
         3 . The electrode according to  claim 1 , wherein
 a Raman spectrum of the oxidation catalyst layer provided on the conductive substrate measured by a Raman spectroscopic analysis has a first peak in a Raman shift of 170 cm −1  or more and 350 cm −1  or less, a second peak in a Raman shift of 450 cm −1  or more and 570 cm −1  or less, and a third peak in a Raman shift of 650 cm −1  or more and 700 cm −1  or less.   
     
     
         4 . The electrode according to  claim 1 , wherein
 the electrode is configured to use as an oxidation electrode of an electrochemical reaction device which reduces carbon dioxide to produce a carbon compound and oxidizes water to produce oxygen.   
     
     
         5 . An electrochemical reaction device comprising:
 a reduction electrode arranged in contact with at least carbon dioxide to reduce the carbon dioxide and thus produce a carbon compound;   the oxidation electrode according to  claim 1  arranged in contact with an electrolytic solution containing water to oxidize the water and thus produce oxygen; and   a power supply to pass an electric current between the oxidation electrode and the reduction electrode.   
     
     
         6 . The device according to  claim 5 , wherein
 the electrolytic solution contains at least one selected from the group consisting of carbon dioxide, hydrogen carbonate ions, and carbonate ions.   
     
     
         7 . The device according to  claim 5 , comprising:
 an electrolytic solution tank including a first accommodation part for accommodating a first electrolytic solution containing the carbon dioxide, and a second accommodation part for accommodating a second electrolytic solution containing the water, wherein   the reduction electrode is arranged in the first accommodation part, and the oxidation electrode is arranged in the second accommodation part.   
     
     
         8 . The device according to  claim 7 , wherein
 at least one of the first electrolytic solution and the second electrolytic solution contains at least one selected from the group consisting of carbon dioxide, hydrogen carbonate ions, and carbonate ions.   
     
     
         9 . The device according to  claim 5 , comprising:
 a first solution flow path to pass a first electrolytic solution so that the first electrolytic solution is in contact with the reduction electrode;   a gas flow path to pass gas containing carbon dioxide so that the carbon dioxide is in contact with the reduction electrode; and   a second solution flow path to pass a second electrolytic solution containing water so that the second electrolytic solution is in contact with the oxidation electrode.   
     
     
         10 . The device according to  claim 9 , wherein
 at least one of the first electrolytic solution and the second electrolytic solution contains at least one selected from the group consisting of carbon dioxide, hydrogen carbonate ions, and carbonate ions.