Carbon-based material, electrode catalyst, oxygen reduction electrode catalyst, gas diffusion electrode, aqueous solution electrolysis device, and method of preparing carbon-based material

Abstract

A carbon-based material in accordance with the present invention includes graphene doped with metal atoms and at least one type of non-metal atoms selected from a group consisting of nitrogen atoms, boron atoms, sulfur atoms, and phosphorus atoms. A diffraction pattern obtained by X-ray diffraction measurement of the carbon-based material by use of CuKα radiation showing that a proportion of the highest of intensities of peaks derived from an inactive metal compound and a metal crystal to an intensity of a (002) peak is 0.1 or less.

1 . A carbon-based material comprising
 graphene doped with metal atoms and at least one type of non-metal atoms selected from a group consisting of nitrogen atoms, boron atoms, sulfur atoms, and phosphorus atoms,   a diffraction pattern obtained by X-ray diffraction measurement of the carbon-based material by use of CuKα radiation showing that a proportion of the highest of intensities of peaks derived from an inactive metal compound and a metal crystal to an intensity of a (002) peak is 0.1 or less.   
     
     
         2 . The carbon-based material according to  claim 1 , wherein
 a proportion of the intensity of the (002) peak of the diffraction pattern obtained by X-ray diffraction measurement of the carbon-based material by use of CuKα radiation to an intensity of a (002) peak of a diffraction pattern obtained by X-ray diffraction measurement of graphite by use of CuKα radiation is 0.002 or less.   
     
     
         3 . The carbon-based material according to  claim 1 , wherein
 a percentage of the metal atoms to carbon atoms of the carbon-based material determined by XPS of 0.5 mass % or more but 10 mass % or less.   
     
     
         4 . The carbon-based material according to  claim 1 , wherein
 a percentage of the non-metal atoms to carbon atoms of the carbon-based material determined by XPS is 1 mass % or more.   
     
     
         5 . The carbon-based material according to  claim 1 , wherein
 the metal atoms include an iron atom.   
     
     
         6 . An electrode catalyst comprising the carbon-based material according to  claim 1 . 
     
     
         7 . An oxygen reduction electrode catalyst comprising the carbon-based material according to  claim 1 . 
     
     
         8 . A gas diffusion electrode comprising the electrode catalyst according to  claim 6 . 
     
     
         9 . An aqueous solution electrolysis device comprising:
 a vessel to receive an aqueous alkali halide solution;   a first electrode and a second electrode to electrolyse an electrolyte liquid to be stored in the vessel;   a power source to apply a voltage between the first electrode and the second electrode so that the first electrode functions as a cathode and the second electrode functions as an anode; and   a cation exchange membrane between the first electrode and the second electrode in the vessel,   the first electrode being the gas diffusion electrode according to  claim 8 .   
     
     
         10 . A method of preparing a carbon-based material, comprising steps of:
 preparing a mixture of graphene oxide, a metal compound, and a non-metal containing compound which contains at least one type of non-metal selected from a group consisting of nitrogen, boron, sulfur, and phosphorus;   reducing the graphene oxide of the mixture to graphene; and   doping the graphene with a metal atom derived from the metal compound and a non-metal atom derived from the non-metal containing compound,   the non-metal containing compound having a molecular weight of 800 or less.   
     
     
         11 . The method of preparing a carbon-based material according to  claim 10 , wherein
 the steps of reducing the graphene oxide and doping the graphene with the metal atom and the non-metal atom are conducted by heating the mixture.   
     
     
         12 . The method of preparing a carbon-based material according to  claim 11 , wherein
 the mixture is heated at a heating temperature of 700° C. or more but 1000° C. or less for a heating time of 10 seconds or more but less than 10 minutes.   
     
     
         13 . The method of preparing a carbon-based material according to  claim 10 , wherein
 the non-metal containing compound includes at least one selected from a group consisting of pentaethylenehexamine, tetraethylenepentamine, triethylenetetramine, and ethylenediamine.