APPLICATIONS OF FULLERENES: CATALYST SUPPORTS FOR AQUEOUS FUEL CELLS

FUEL CELLS OPERATING IN AQUEOUS ELETROLYTES (BELOW 200¿C, DEPENDING ON THE CHOSEN ELECTROLYTE TECHNOLOGY) NORMALLY OPERATE ON HYDROGEN FUEL AND OXYGEN (OR AIR) AS THE OXIDANT. HIGH-PERFORMANCE FUEL CELL ELECTRODES REQUIRE HIGH CATALYST SURFACE AREAS, GOOD ELECTRONIC CONDUCTIVITIES AND BROAD REACTION ZONES, DEFINED BY THE CONTACT AREA BETWEEN THE CATALYST, THE GAS PHASE REACTANT AND THE ELECTROLYTE. FOR ELECTRODES OF THIS TYPE, A STABLE, LOW-DENSITY, ELECTRONICALLY CONDUCTING CATALYST SUPPORT IS REQUIRED. HIGH SURFACE AREA CARBON BLACKS ARE USUALLY USED, WITH AREAS BETWEEN 250 AND 450 M(2)G(-1). SUCH CARBON BLACKS SUPPORT RATHER STABLE PLATINUM CRYSTALLITES WITH SURFACE AREAS OF ABOUT 100 M(2)G(-1) IN A 10 WT % LOADING PREPARED BY COLLOIDAL METHODS. THEY ARE USED IN ALL SITUATIONS WHERE CARBON BLACKS ARE STABLE. HOWEVER, ALL CARBON MATERIALS ARE LACKING IN STABILITY TO A GREATER OR LESSER DEGREE FOR FUEL CELL APPLICATIONS REQUIRING THE HIGHEST PERFORMANCE. AN IMPROVEMENT IN PROPERTIES IS REQUIRED. THE ESSENTIALLY AROMATIC FULLERENES WITH NO DANGLING BONDS AND RATHER INERT SURFACES MAY HAVE THE APPROPRIATE STABILITY IN AQUEOUS SOLUTIONS. THEY HAVE HIGH SURFACE AREAS (800 M(2)G(-1) FOR THE OUTSIDE SURFACE OF C(60)) AND SHOULD HAVE GREATER STABILITY THAN COMMON GRAPHITE EDGE PLANES. NO EXPERIMENTAL DATA ON THEM HAS BEEN REPORTED IN AQUEOUS MEDIA. THE PURPOSE OF THIS PROPOSAL IS TO EXAMINE THE BASIC ELECTROCHEMISTRY OF FULLERENES IN AQUEOUS MEDIA, INVESTIGATE THEIR OXIDATION/CORROSION BEHAVIOR AND DETERMINE THEIR ELECTRODE POTENTIAL REGIONS OF STABILITY FOR FUEL CELL APPLICATIONS. IF SUCCESSFUL, FULLERENES CAN BRING ABOUT A GREAT IMPROVEMENT IN AQUEOUS FUEL CELL PERFORMANCES BY PERMITTING OPERATION UNDER MORE EXTREME CONDITIONS. ANTICIPATED BENEFITS/POTENTIAL APPLICATIONS - REPLACEMENT OF EASILY DEGRADED CARBON BLACKS AND/OR GRAPHITE POWDERS IN EXISTING FUEL CELL ELECTRODE STRUCTURES WITH FULLERENE MATERIALS WILL GIVE ENHANCED STABILITY TO, AND IMPROVED PERFORMANCE FROM, A NEW GENERATION OF FUEL CELL ELECTRODES. TECHNOLOGY ARISING FROM THIS PROJECT WILL GIVE RISE TO OXIDATION RESISTING, CHEMICALLY AND ELECTROCHEMICALLY STABLE, HIGH-PERFORMANCE NOBLE METAL-CATALYZED ELECTRODES SUITABLE FOR USE IN AQUEOUS F