Spectroscopic identification of the adsorbed intermediate in hydrogen evolution on platinum

Investigations using in-situ IR spectroscopy of adsorbed hydrogen on polycrystalline Pt, Rh, Ir and single crystal Pt(111) electrodes in acid solution allow the identification of a new type of this adsorbate. The absorption band at about 2090 cm−1 enables it to be identified as a hydrogen atom singly coordinated on top of a surface metal atom. It is concluded that this adsorbed hydrogen is the intermediate in the hydrogen evolution reaction from correlations between the potential dependence of the band intensity and the rate of hydrogen formation.