Preparation and characterization of doped glassy carbon materials: Application to fuel cell electrodes.

摘要

The influence of the preparative conditions on the morphology and the activity of platinum-doped glassy carbon (Pt-DGC) materials was investigated. The carbon phase was characterized by SEM and Raman analyses. The determination of the average Pt cluster size and size distribution was performed by TEM. XPS analyses allowed the determination of the surface concentration in Pt. Electrochemical studies were performed on Pt-DGC thin films. It was found that the presence of residual oxygen during thermolysis enhances the graphitization and partially oxidizes the developing carbon matrix. Larger clusters are also observed when oxygen is present in the curing environment, as a consequence of the increased porosity of the carbon matrix. The more porous films were the most electrocatalytically active, because of an increase in the electrode surface area, and more accessible Pt clusters.; Pt-DGC catalysts were successfully dispersed at both the anode and the cathode of H{dollar}sb2{dollar}/O{dollar}sb2{dollar} fuel cells. The resulting cells performed comparably to those prepared from commercial catalysts in terms of activity, and better in terms of activity per mg of Pt.; Thermolysis of a ruthenocene-containing oligomer precursor prepared by Glaser-Eglinton oxidative coupling of a diacetylenic monomer resulted in the formation of ruthenium-doped glassy carbon (Ru-DGC). This material was characterized by the same analytical techniques than Pt-DGC. Similar conclusions were reached with respect to the influence of the thermolysis conditions on both the morphology and the electrocatalytic activity of Ru-DGC. Ru-DGC thin films were found to be electrochemically active toward both the oxygen evolution and the chlorine evolution reactions.; Platinum/ruthenium-doped glassy carbon (Pt/Ru-DGC) was prepared by thermolysis of a bimetallic oligomer precursor. Investigation of the properties of Pt/Ru-DGC was achieved by the techniques described above. It was found that thermolysis results in the formation of bimetallic particles. The electrochemical activity of Pt/Ru-DGC toward the methanol oxidation reaction makes it a potential candidate as a catalyst for the anode of a direct methanol fuel cell.