Electrooxidation of hypophosphite on single-crystal nickel electrodes: an in situ IR study

SNIFTIRS studies on the electrooxidation of hypophosphite at polycrystalline and single-crystal nickel electrodes have indicated that the process is dependent upon the structure of the crystal plane exposed to the electrolyte. Of the surfaces studied, Ni(210) was the most catalytically active and the order changed as follows: (210) > (111) > (100). The hypophosphite was found to be adsorbed via its two hydrogen atoms. The adsorption on (210) and (111) is characterised by a considerable distortion of the H—P—H angle prior to the oxidation of the anion. The adsorption is also characterised by an accompanying loss of Ni—H species from the surface. The use of deuteriated water identified the solvent as the source of the hydrogen atoms rather than the hypophosphite.