IN-SITU POTENTIAL MODULATION DIFFERENCE DIFFRACTION STUDIES OF PLATINUM IN SULFURIC-ACID USING SYNCHROTRON X-RAY-RADIATION

In-situ potential-modulated X-ray diffraction (XRD) studies of platini zed platinum electrodes in 1 M sulphuric acid were undertaken using sy nchrotron X-ray radiation. During these studies, the potential of the platinized electrodes was repeatedly stepped between values correspond ing to the 'double-layer' region and oxide formation and potentials wi thin the hydrogen adsorption region. Subtle differences between these sets of XRD patterns led to the conclusion that there was a slight shi ft in the position of each of the XRD peaks when the electrode potenti al was changed. These data are consistent with an increase in d-spacin g at potentials in the oxide region and a decrease at potentials corre sponding to the weakly adsorbed hydrogen region.