Preparation, characterization and properties of Pt-CuCo-reduced and Pt-on-Cu skin type bimetallic carbon-supported (Vulcan XC72) electrocatalysts

Pt/Cu salt co-reduction and, subsequent reduction of Cu(acac)2 and PtCl2 allows to generate either alloyed Pt-Cu or skin type Pt-on-Cu carbon-supported (20 wt%, Pt:Cu = 50:50 a/o on Vulcan XC72) electrocatalysts. An examination by TEM revealed that the co-reduced Pt-Cu catalyst have well dispersed bimetallic nanoparticles (av. particle size 3.6 nm). The skin type Pt-on-Cu catalyst shows tiny Pt clusters (1-2 nm) decorating the surface of larger Cu particles (6-8 nm). XRD pat- tern of the co-reduced Pt-Cu catalyst shows weak and broad diffraction peaks consistent with a predominantly alloyed composi- tion (plus a few Pt crystallites). Pattern of the skin type Pt-on-Cu/C catalyst reveals larger nanoparticles and points to the formation of (surface) alloy. SEM/EDAX showed a uniform metal distribution present in both Pt-Cu systems. XPS measure- ments indicated that in both cases only Pt o is present. In co-reduced alloy catalyst a higher amount of Cu 2+