Direct Methanol Fuel Cells:The Influence of Methanol on the Reduction of Oxygen Over Pt/C Catalysts with Different Particle Sizes

摘要

Two Pt/C catalysts with different particle sizes(Pt/C:2.5 nm,Pt/C-700Ar:5.1 nm)were investigated by applying a half-cell configuration-rotating disk electrode(RDE)technique in H_2SO_4 aqueous solutions in the absence of or in the presence of methanol with different concentrations.Pt/C catalyst exhibited higher mass activity in H_2SO_4 aqueous solution without methanol and slightly lower mass activity in H_2SO_4 plus 0.1 mol/L CH_3OH in comparison with that of Pt/C-700Ar catalyst.On the contrary,single direct methanol fuel cell(DMFC)tests showed that Pt/C exhibited higher oxygen reduction reaction(ORR)activity and better cell performance,mainly due to the different kinds of electrolyte properties.Furthermore,it suggested that a better single DMFC performance could be obtained with a smaller particle size Pt-based cathode catalyst.