Co2 reduction catalyst, co2 reduction electrode and co2 reduction device

Abstract

The present embodiments provide a CO 2 reduction catalyst which is used for a reduction reaction of carbon dioxide and shows a high efficiency in water, and a CO 2 reduction electrode and a CO 2 reduction device, which contain the CO 2 reduction catalyst. This catalyst contains a conductive material and a porphyrin complex which has a specific structure and is insoluble in water. The porphyrin complex is insoluble in water because it contains only a small number of hydrophilic groups in its structure. The CO 2 reduction electrode and the CO 2 reduction device contain this catalyst.

1 . A CO 2  reduction catalyst comprising:
 a conductive material; and   a porphyrin complex which is carried on said conductive material and represented by the following Formula (A):   
       
         
           
           
               
               
           
         
         wherein, each R independently represents a group selected from the group consisting of hydrogen, hydrocarbon groups having 1 to 12 carbon atoms, a hydroxyl group, an amino group, a carboxy group, a sulfo group, a mercapto group and a formyl group and are optionally the same or different, and adjacent R groups are optionally bound with each other via a hydrocarbon chain having 1 to 12 carbon atoms to form a cyclic structure; 
         M represents a (2+n)-valent metal ion, wherein n is a number of 0 or larger; 
         X represents an n-valent anion; and 
         the total number of hydroxyl groups, amino groups, sulfo groups and mercapto groups that are contained in one molecule of said porphyrin complex is 10 or less. 
       
     
     
         2 . The CO 2  reduction catalyst according to  claim 1 , wherein said metal ion is Fe ion. 
     
     
         3 . The CO 2  reduction catalyst according to  claim 1 , wherein said total number of hydroxyl groups, amino groups, sulfo groups and mercapto groups that are contained in one molecule of said porphyrin complex is 8 or less. 
     
     
         4 . The CO 2  reduction catalyst according to  claim 1 , wherein said porphyrin complex is represented by the following Formula (A-1) or (A-2): 
       
         
           
           
               
               
           
         
         wherein, each R independently represents a group selected from the group consisting of hydrogen, hydrocarbon groups having 1 to 12 carbon atoms and are optionally the same or different, and adjacent R groups are optionally bound with each other via a hydrocarbon chain having 1 to 12 carbon atoms to form a cyclic structure; and 
         said hydrocarbon groups and hydrocarbon chain are optionally substituted with a hydroxyl group, an amino group, a carboxy group, a sulfo group, a mercapto group or a formyl group, with a proviso that the total number of hydroxyl groups, amino groups, sulfo groups and mercapto groups that are contained in one molecule of said porphyrin complex is 10 or less. 
       
     
     
         5 . The CO 2  reduction catalyst according to  claim 1 , further comprising a surfactant. 
     
     
         6 . A method of reducing carbon dioxide, said method comprising:
 bringing a CO 2  reduction electrode comprising the CO 2  reduction catalyst according to  claim 1  into contact with an electrolyte solution; and   introducing carbon dioxide to said electrolyte solution and reducing the thus introduced carbon dioxide by said electrode.   
     
     
         7 . A CO 2  reduction device comprising:
 an oxidation electrode;   a CO 2  reduction electrode comprising the CO 2  reduction catalyst according to  claim 1 ; and   a power supply element connected to said oxidation electrode and said CO 2  reduction electrode.   
     
     
         8 . The device according to  claim 7 , wherein said power supply element comprises a semiconductor layer which performs charge separation with light energy.