Electrochemical and Eiectrocatalytic Behavior of an Iron-Base Amorphous Alloy in Alkaline Solutions at 70~

An alloy exhibit ing high electrocatalytic activity for the hydrogen evolut ion reaction (HER) has been prepared by anodic oxidation of amorphous Fe60Co20Si,0B10 in 30 weight percent (w/o) KOH at 70 ~ Electrochemical studies show that the anodic process involves a dissolution-precipitation mechanism for the Fe(II) species. Surface studies by SEM, EDX, AES, and x-ray diffraction reveal that the electrode produced is covered by a thick and porous film of Fe304. At the be-ginning of the HER, the oxidized electrode is reduced and fine Fe particles are formed on the amorphous matrix. It is sug-gested that the reduct ion mechanism involves also a dissolution-precipitation process. The iron particles grow and coa-lesce during the first thousand seconds, producing a highly porous material. After anodic oxidation at 1 mAcm-2 and hydrogen evolut ion of 10 % at-1.3V, the Tafel slope is 77 mV and the exchange current density is 2.3 mAcm-2 in 30 w/o KOH, 70~ The search for stable and low overpotential morphous electrocatalysts for hydrogen evolut ion in concentrated alkaline solutions is a growing area of concern. In recent years, there has been appreciable research on the electro-catalytic behavior of amorphous alloys for the HER (1, 2)