In situ decoration of stainless steel nanoparticles for synergistic enhancement of α-Ni(OH)2 oxygen evolution reaction catalysis

Abstract

Alkaline water-splitting is a promising clean technology for hydrogen production. However, reducing the oxygen evolution reaction (OER) overpotential is critical to the overall process efficiency and economic feasibility. To this end, we demonstrate novel 3D hierarchical α-Ni(OH)₂ nanoparticle decorated stainless steel nanoparticle (SSNP) catalyst deposits on Ni foam substrates. SSNP deposition along with simultaneous in situ Ni(OH)₂ decoration of the SSNP is facilitated via a facile single-step electrophoretic deposition (EPD) based co-deposition method. The enhanced OER catalytic activity of α-Ni(OH)₂ owing to the synergistic SSNP support, which possibly serves as a dopant source to the metal hydroxide, could sustain current densities of 10 and 125 mA cm⁻² at overpotentials of 220 and 250 mV respectively, in 1 M KOH. These robust deposits could survive accelerated cycling and prolonged oxygen generation at higher current densities despite the lack of any polymeric binders. In 10 M KOH, a current density of 500 mA cm⁻² could be maintained at an overpotential of 450 mV (iR-uncorrected).