Pt particles with different nanosizes were loaded on reduced graphene oxides by a hydrothermal synthesis method. The morphology and composite of the products were examined by SEM and XPS. The hydrogen sensing properties of Pt-r GO based gas sensor were measured. The results indicate that the sample with smaller Pt particles has better hydrogen sensing property than that of the larger Pt particles sample in the operating temperature range of 50-150 ℃. The hydrogen sensing property of the Pt-doped reduced gra...