Patent ID: 8304362

Claim:
Catalyst particles comprising a core/shell structure of M core /M shell wherein M core =metal of inner particle core, and M shell =metal of outer particle shell and wherein said catalyst particles have a medium diameter (d core+shell ) in the range of 20 to 100 nm and wherein the outer particle shell (M shell ) comprises a precious metal selected from the group consisting of ruthenium (Ru), osmium (Os), rhodium (Rh), iridium (Ir), palladium (Pd), platinum (Pt), silver (Ag), gold (Au) and alloys or mixtures thereof and comprises at least 3 atomic layers and its surface is polycrystalline and has the characteristics of a bulk precious metal surface, wherein the thickness of the outer particle shell (t shell ) is about 5 to 20% of the diameter of the inner particle core (d core ): t shell =˜0.05 to 0.2 d core wherein t shell =(d core+shell −d core )/2, and wherein the inner particle core (M core ) comprises a base metal or a precious metal.