Anodic Etching of Amorphous Ni₈₁P₁₉ Alloy in Hot Concentrated Chloride Solution for Enhanced Hydrogen Evolution in Alkaline Water Electrolysis

Abstract

Highly active and easily available electrocatalysts are of great importance for a wider use of water electrolysis for hydrogen production. Herein, electroactivity toward hydrogen evolution reaction was examined in 1.0 M KOH on commercial Ni 81 P 19 (MBF-60) and Ni 70 Cr 6 Fe 2 B 14 Si 8 (MBF-20A) amorphous alloys and for comparison on Ni, untreated and modified by anodic etching in hot concentrated NaCl solutions. This treatment increased the electroactivity of all the materials, but especially of Ni 81 P 19 and particularly of matte side of its ribbons, decreasing overpotential at À 10 mA cm À 2 to À 0.14 V. XRD, SEM/EDS and XPS studies were carried out. EIS measurements indicated that the rise of hydrogen evolution after etching was related mainly to the increase of surface area, and only slightly to the rise of intrinsic electroactivity, probably being due to the formation of NiO. It is proposed that etched Ni 81 P 19 might be an efficient cathode for hydrogen production by water electrolysis.