Direct methanol fuel cell (DMFC) has attracted wide attention due to its many advantages. However, its practical application is limited by the low electrocatalytic activity of the anodic Pt/C catalyst usually used for the methanol oxidation. In this paper, in order to increase the electrocatalytic performance of the Pt/C catalyst for the methanol oxidation, the black carbon, usually used as the supporter, was pretreated with CO₂, air, HNO₃ or H₂O₂. The cyclic voltammetric results indicated that the current densities of the anodic peak of methanol oxidation at the Pt/C catalysts with the black carbon pretreated with CO₂, air, HNO₃, H₂O₂ and untreated black carbon were 39, 33, 32, 20 and 18 mA•cm^－2, respectively, illustrating that among the above five kinds of the Pt/C catalysts, the Pt/C catalyst with the black carbon pretreated with CO₂ shows the best electrocatalytic activity and stability for the methanol oxidation. Its main reason is that the CO₂ pretreatment could reduce the content of the oxygen-containing groups on the surface of the black carbon and increase the content of graphite in the black carbon, leading to the low resistance of the black carbon and the increase in the dispersion extent of the Pt particles in the Pt/C catalyst.

Key words: direct methanol fuel cell, methanol oxidation, black carbon, pretreatment