Synthesis and Characterization of Monolayer Bimetallic Surfaces: A Synchrotron NEXAFS and XPS Study
R. Rettew, J. Guthrie, Cherno Jaye, Daniel A. Fischer, Faisal Alamgir
Surface limited redox replacement (SLRR) is a potentially powerful tool for atomic monolayer-scale model catalyst fabrication for a plethora of spectroscopic techniques. This paper compares overpotential Ni deposition as an intermediary for SLRR with the traditional Cu intermediary method. It also presents the use of SLRR to fabricate samples for study using near-edge x-ray absorption fine structure (NEXAFS.) We present the use of NEXAFS spectroscopy to study adsorbate bonding strengths on this type of bimetallic model catalyst. We report a correlation between the strength of the adsorbate-Pt bond as a function of the thickness of Pt overlayers. Deposition of Pt on polycrystalline and single crystalline Au has been conducted via Ni and Cu replacement, respectively. The growth of Pt overlayers has been characterized by X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV).