The effective Pt surface area (S(e)Pt), which was directly calculated from the Pt particle size distribution, based upon the comparison of TEM, SEM and 3D images, was increased by using the AB supports: 87 m2 gPt 1 for the n-Pt/AB800 catalyst and 107 m2 gPt 1 for the n-Pt/ AB250 catalyst, both being higher than that of the c-Pt/CB catalyst (32 m2 gPt 1).