Cathodic corrosion induced selective nano-crystallization of Nickel oxo/ hydroxo complex on (NiFeCr)SiB amorphous ribbon for alkaline oxygen evolution reaction and methanol oxidation reaction

The study focuses on the development and optimization of (Ni87Fe4Cr9)78Si8B14 amorphous ribbons as selfsupported electro-catalysts for oxygen evolution reaction (OER) and methanol oxidation reaction (MOR). Electro-catalytically active nano alpha-Ni(OH)2 phase (5-10nm) was generated in the amorphous ribbon surface through potentiostatic cathodic corrosion for different time intervals (0-120 min). The X-ray diffraction and scanning electron microscopy results shows the favourable occurrence of dense nanocrystallization of alpha-Ni(OH)2 between 45 and 90 min of corrosion time. For OER in 1 M KOH, the 60-min surface modified ribbon exhibits an overpotential of 295 mV at 10 mA/cm2 current density and tafel slope of 51 mV dec-1. In case of MOR in 1 M KOH +1 M MeOH, the 90-min corroded ribbon shows lowest potential of 1.38 V vs RHE, at 10 mA/cm2 and tafel slope of 34 mV dec-1. In addition to superior electro-catalytic activity, the optimal surface-modified ribbons show superior long-term stability for OER and MOR studies, indicating its potential application in hydrogen generation and direct methanol fuel cell.