Structural investigation by electrochemically modulated infrared spectroscopy of adsorbed hydrogen on rhodium

Abstract

Measurements were made, in situ, by IR reflectance spectroscopy at a rhodium electrode in 1 M H 2SO 4 and mixed H 2SO 4/D 2SO 4 electrolytes to give spectra corresponding to the difference between the state of the electrode at a potential in the double layer region and at a potential in the hydrogen adsorption region. A model for weakly adsorbed hydrogen in which the adsorbed atom is bonded to an oriented water structure is deduced from the spectral data. The spectra also show the presence of a strongly bound hydrogen species although the voltammetry shows no separate feature for its formation.