In this article, Pt films treated with oxygen plasma immersion ion implantation were analyzed with the grazing-incident X-ray diffraction and X-ray photoemission spectrometry. Due to the oxygen implantation, an amorphous layer was created under the negative substrate pulses, -2 and -5 kV, applied to the Pt films. The amount of oxygen implanted is substantially higher for the larger substrate pulse applied. The primary Pt binding state in the implanted layer also depends on the substrate pulse; it appears to be NO and PtO2, respectively for -2 and -5 W of substrate pulse. Upon annealing, appreciable amount of oxygen has escaped from the implanted Pt surface, and oxygen remaining in Pt could be detected only from the sample treated with -5 kV pulse. (c) 2005 Elsevier B.V. All rights reserved.