Electrode catalyst layer for electrolytic cell, electrode for electrolytic cell, and carbon dioxide electrolytic device

Abstract

An electrode catalyst layer for electrolytic cell 3 of an embodiment includes: a carbon material; a metal catalyst supported on the carbon material; and a water-repellent organic substance. In the electrode catalyst layer for electrolytic cell of the embodiment, the water-repellent organic substance includes an organic substance containing sulfur. A metal-sulfur bond is formed between the organic substance containing sulfur and the metal catalyst. A mass ratio (S/M) of a sulfur element (S) to a metal element (M) in the metal catalyst in the catalyst layer is not less than 0.03 nor more than 0.1.

What is claimed is: 
     
         1 . An electrode catalyst layer for electrolytic cell of carbon dioxide, the electrode catalyst layer comprising: a carbon material; a metal catalyst supported on the carbon material; and a water-repellent organic substance, wherein
 the water-repellent organic substance includes an organic substance containing sulfur,   the organic substance containing sulfur has a metal-sulfur bond formed between the sulfur and the metal catalyst, and   a mass ratio of a sulfur element to a metal element in the metal catalyst in the catalyst layer is 0.03 or more and 0.1 or less.   
     
     
         2 . The electrode catalyst layer according to  claim 1 , wherein the organic substance containing sulfur is contained in a range of 5 mass% or more and 25 mass% or less to a total mass of the carbon material, the metal catalyst, and the water-repellent organic substance. 
     
     
         3 . The electrode catalyst layer according to  claim 1 , wherein a mass ratio of the organic substance containing sulfur to the metal catalyst is 0.3 or more and 0.9 or less. 
     
     
         4 . The electrode catalyst layer according to  claim 1 , further comprising an ion-conductive material,
 wherein a solid mass of the ion-conductive material is 0.1 times or more and 1 time or less to a total mass of the carbon material and the metal catalyst.   
     
     
         5 . The electrode catalyst layer according to  claim 1 , further comprising a carbon fiber having an average diameter of 10 nm or more and 100 nm or less and an average length of 5 µm or more and 100 µm or less,
 wherein a ratio of the carbon fiber in the catalyst layer is 10 mass% or more and 70 mass% or less. 
 
     
     
         6 . The electrode catalyst layer according to  claim 1 , wherein the organic substance containing sulfur has a thiophene ring. 
     
     
         7 . The electrode catalyst layer according to  claim 1 , wherein a thickness of the catalyst layer is 5 µm or more and 200 µm or less. 
     
     
         8 . The electrode catalyst layer according to  claim 1 , wherein the carbon material includes at least one selected from the group consisting of a carbon particle, a carbon nanotube, activated carbon, and graphene. 
     
     
         9 . The electrode catalyst layer according to  claim 1 ,
 wherein the metal catalyst includes at least one metal selected from the group consisting of gold, silver, copper, platinum, palladium, nickel, cobalt, iron, manganese, titanium, cadmium, zinc, indium, gallium, lead, and tin, an alloy containing the metal, or an oxide of the metal, and   wherein the metal catalyst has at least one structure selected from the group consisting of a nanoparticle, a nanostructure, and a nanowire.   
     
     
         10 . The electrode catalyst layer according to  claim 1 , wherein a mass of the metal catalyst per unit area of the catalyst layer is 0.01 mg/cm 2  or more and 5 mg/cm 2  or less. 
     
     
         11 . The electrode catalyst layer according to  claim 4 , wherein the ion-conductive material includes a cation exchange resin or an anion exchange resin. 
     
     
         12 . An electrode for electrolytic cell comprising:
 a conductive base material; and   the electrode catalyst layer according to  claim 1 , provided on the conductive base material.   
     
     
         13 . The electrode according to  claim 12 , wherein the conductive base material includes a material containing at least one selected from the group consisting of titanium, nickel, iron, and carbon. 
     
     
         14 . The electrode according to  claim 12 , wherein the conductive base material has at least one selected from the group consisting of a mesh material, a punched material, a porous body, and a metal fiber sintered compact. 
     
     
         15 . A carbon dioxide electrolytic device comprising:
 an electrolytic cell including a cathode part having a cathode constituted of the electrode according to  claim 12 , which is disposed to be in contact with carbon dioxide and reduces the carbon dioxide to produce a carbon compound, and a gas flow path to supply carbon dioxide to the cathode, an anode part having an anode disposed to be in contact with an anode solution containing water or a hydroxide ion and oxidize the water or the hydroxide ion to produce oxygen, and an anode solution flow path to supply the anode solution to the anode, and a separator separating the cathode part and the anode part;   a gas supply part to supply carbon dioxide to the gas flow path; and   a solution supply part to supply the anode solution to the anode solution flow path,   wherein the cathode and the anode are configured to be supplied with current from a power supply.