SURFACE-CHEMISTRY AND ELECTROCATALYTIC ACTIVITY OF THE HER ON NICKEL MODIFIED WITH HETEROPOLYACIDS

Nickel was modified at the surface from dilute acid solution containing different concentrations of PMo12O40(3-), SiW12O40(4-), or PW12O40(3-). It was shown that improvement in the over potential (eta) and in the exchange current density of the hydrogen evolution reaction (HER) in KOH 3M on the electrode depends on the nature of the heteropolyacid of the modification bath. The best electrocatalytic parameters were obtained on electrodes modified with PMo12O40(3-). The surface chemical composition of the electrode was determined by x-ray photoelectron spectroscopy. The HER electrocatalytic activities of the modified electrodes were correlated to their surface chemical composition. The products of the modified electrodes have been identified before and after using the electrodes for HER in alkaline medium.