| 摘要 |
PROBLEM TO BE SOLVED: To increase the adhesive strength of metal particles to a carbon base material and to decrease the loss of the metal particles before depositing the metal particles on the carbon base material by treating the carbon base material in an alkali medium of high concn. at a specified temp. for a specified time in an oxygen-concn. gas flow. SOLUTION: Metal particles of platinum or a mixture of platinum and silver as a catalyst are deposited by a dip-reducing method on a granular carbon material such as graphite having a large specific surface area. The obtd. carbon base material carrying the catalyst is used for the production of electrodes of a cathode for oxygen reduction in an electrolytic cell. Before depositing the metal particles on the carbon base material, the carbon base material is charged in an alkali medium and treated at least for 2 hours, preferably about >=24 hours at 50 to 100 deg.C, preferably about 90 deg.C while blowing an oxygen-contg. gas. The alkali medium is the hydroxide of alkali metal and especially preferably, NaOH is used in an aq. soln. having at least >=30 wt.%, preferably 30 to 60 wt.%. The oxygen-contg. gas preferably contains >=20 vol.% O2 and especially oxygen gas is preferable. |
