In situ back-side illumination fluorescence XAFS (BI-FXAFS) studies on platinum nanoparticles deposited on a HOPG surface as a model fuel cell: a new approach to the Pt-HOPG electrode/electrolyte interface

Abstract

We measured the in situ polarization-dependent X-ray absorption fine structure of platinum nanoparticles (PtNPs) deposited on a flat highly oriented pyrolytic graphite (HOPG) substrate under electrochemical conditions using a back-side illumination method. In this method, the thin HOPG substrate with PtNPs deposited on one side was used as a window for incident and fluorescent X-rays, as well as an electrode. A bent crystal Laue analyzer (BCLA) was applied to the extraction of the Pt L_α fluorescent X-ray signals from strong scattered X-rays. Pt L₃ edge XAFS spectra were observed for various electrode potentials and polarization directions.