NI-BASE AMORPHOUS-ALLOYS AS ELECTROCATALYSTS FOR ALKALINE WATER ELECTROLYSIS

The development of efficient and cost effective electrodes for hydroge n generation from water electrolysis and for hydrogen oxidation in pow er generation from fuel cells is very important in developing the hydr ogen economy. This paper focuses on the role of the structure and chem istry of amorphous metal alloys (AMA) on the electrocatalytic activity for the hydrogen evolution reaction (HER) in alkaline water electroly sis. The test AMA electrodes, Ni-base alloys with different metal addi tive ratios, were prepared by a planar flow casting technique. The ele ctrochemical behaviour of the AMA was investigated in 1 M KOH at 30 de grees C by cyclic voltammetry and steady-state polarization techniques . The AMA displayed voltammetric responses similar to that of crystall ine Ni, however, differences were found in the oxide formation mechani sm. The electrocatalytic activities of the AMA were dependent on the A MA composition. The prepared alloys displayed good stability relative to that of crystalline Ni. Even after extensive potential cycling whic h roughened and attacked the crystalline Ni electrodes, the surfaces o f the amorphous alloys remained smooth. As a result of the roughening of the crystalline Ni electrodes, the amorphous alloys appeared to be less active than crystalline Ni for the HER on the basis of geometric surface area. (C) 1997 International Association for Hydrogen Energy. All rights reserved.