In the first step, Pt NPs were deposited onto a commercial carbon black support (Ketjen Black EC300J) via double passivation galvanic displacement method reported elsewhere. In the second step, the prepared composites with deposited Pt NPs were thermally annealed in order to obtain an alloy crystal phase. In the last step, the electrocatalysts were subjected to two different activation (acid washing) protocols and thus, formation of a Pt-rich overlayer via dealloying. Within this study, Pt-rich overlayer should be understood that the top-most layers of the Pt-alloy NPs have a more Pt-rich chemical composition than the bulk of the Pt-alloy NPs.