Fuel cell and process for production thereof; and electronic instrument, mobile machine, electric power generating system, cogeneration system, and electrode reaction-based apparatus

Abstract

A porous electroconductive material is provided. The electroconductive material enables efficient enzymatic metabolic reactions on electrodes and yields electrodes having immobilized enzymes thereon which remain stable in any working environment. The porous electroconductive material, which has a three-dimensional network structure, is formed from a skeleton of porous material and a carbonaceous material covering the surface of the skeleton. The porous material constituting the skeleton is foamed metal or alloy. This porous electroconductive material is made into an electrode, and enzymes are immobilized on this electrode. The resulting electrode with immobilized enzymes thereon is used as the anode of a bio-fuel cell.

1 . A fuel cell comprising:
 a cathode;   an anode; and   a proton conductor disposed between the cathode and the anode, at least one of the cathode and the anode being an electrode with immobilized enzymes formed thereon,   wherein said electrode is an electrode of a porous electroconductive material including a skeleton of a porous material, and a material composed mainly of carbonaceous material which covers at least a portion of the skeleton.   
   
   
       2 . A method of producing a fuel cell having a cathode, an anode, and a proton conductor disposed therebetween, at least one of the cathode and the anode being an electrode with immobilized enzymes formed thereon, the method comprising:
 coating the surface of a skeleton of a porous material at least partly with a material composed mainly of carbonaceous material, thereby forming a porous electroconductive material,   molding the porous electroconductive material into an electrode, and   immobilizing enzymes on the electrode.   
   
   
       3 . An electronic instrument comprising:
 a fuel cell having a cathode, an anode, and a proton conductor disposed therebetween, at least one of the cathode and the anode being an electrode with immobilized enzymes formed thereon,   wherein said electrode is an electrode of a porous electroconductive material including a skeleton of a porous material, and a material composed mainly of carbonaceous material which covers at least a portion of the skeleton.   
   
   
       4 . A mobile machine comprising:
 a fuel cell having a cathode, an anode, and a proton conductor disposed therebetween, at least one of the cathode and the anode being an electrode with immobilized enzymes formed thereon,   wherein said electrode is an electrode of a porous electroconductive material including a skeleton of a porous material, and a material composed mainly of carbonaceous material which covers at least a portion of the skeleton.   
   
   
       5 . An electric power generating system comprising:
 a fuel cell having a cathode, an anode, and a proton conductor disposed therebetween, at least one of the cathode and the anode being an electrode with immobilized enzymes formed thereon,   wherein said electrode is an electrode of a porous electroconductive material including a skeleton of a porous material, and a material composed mainly of carbonaceous material which covers at least a portion of the skeleton.   
   
   
       6 . A cogeneration system comprising:
 a fuel cell having a cathode, an anode, and a proton conductor disposed therebetween, at least one of the cathode and the anode being an electrode with immobilized enzymes formed thereon,   wherein said electrode is an electrode of a porous electroconductive material including a skeleton of a porous material, and a material composed mainly of carbonaceous material which covers at least a portion of the skeleton.   
   
   
       7 . An electrode reaction-based apparatus comprising:
 at least one electrode with immobilized enzymes formed thereon,   wherein said electrode is an electrode of a porous electroconductive material including a skeleton of a porous material, and a material composed mainly of carbonaceous material which covers at least a portion of the skeleton.   
   
   
       8 . The electrode reaction-based apparatus according to  claim 7 , which is any of a fuel cell, a biosensor, and a bioreactor.