Abstract: In this work, the surface of GO was functionalized by different method and used to load noble metal Pd. It is found that the surface modification of GO can effectively enhance the loading amount of Pd and reduce the Pd agglomeration on the support surface, and thereby improve the catalytic activity of Pd-based catalyst for oxidation of formic acid. The activity of Pd-based electrocatalyst toward the oxygen reduction-reaction(ORR) was examined using cyclic voltammetry through roating-disk electrode measurements in 0.5 mol/L H2SO4 electrolyte. Under the same experimental conditions, the loading amount and the catalytic performance of Pd on graphene oxide(GO), reduced graphene oxide(RGO) and sulfonated graphene(SGO) were studied. The results show that SGO is easier to load Pd and the obtained composite catalyst for CO tolerance is also improved significantly, which may be due to the synergetic effect from the π-π bonding of graphene and the van der Waals interactions of the —SO3H functionality, enhancing the loading and dispersion of Pd on the supporting materials effectively.

Key words: direct formic acid fuel cell, graphene oxide, functionalized