Dissolution of equimolar Pt-M (M: Co, Ni, Fe) alloys covered with a Pt-enriched layer on the surface has been studied under potential cycling in 0.5 M H2SO4 solution at 25 degrees C. The Pt-enriched layer was formed on the surface of Pt-M alloys by a selective dissolution treatment of M under immersion condition in the solution. The amounts of Pt and M dissolved under potential cycling with various combinations of upper potential limit E-upper and lower potential limit E-lower were determined with an inductively coupled plasma mass spectrometry (ICP-MS). During the selective dissolution treatment, rest potential E-rest of the Pt-M alloys approaches to that of pure Pt, indicating the enrichment of Pt on the surface. The Pt-enriched layer strongly suppresses further selective dissolution of M under the immersion condition. However, when the Pt-M alloys are exposed under potential cycling in the potential ranges of E-upper > E-rest (approximate to 1.0V vs. SHE) and E-lower < 0.5 V. the selective dissolution of M takes place again, although it is suppressed at the initial stage of the potential cycling by formation of the thicker Pt-enriched layer. (C) 2012 Elsevier Ltd. All rights reserved.