This study compared the activity of electrochemically deposited Pt thin films on nanoporous and smooth Au rods with various Pt thicknesses for CO oxidation. With increasing Pt thickness from 1 to 4 monolayers (ML), the activity in CO oxidation increased. Nanoporous Au rods, on which 4 ML of Pt were deposited, showed similar to 30 times higher CO oxidation activity than smooth ones with the same amount of Pt. A higher surface area of nanoporous Au resulted in a catalytic activity of the Pt films on porous Au superior to those of the respective smooth surfaces. (C) 2009 Elsevier B.V. All rights reserved.