Ni-Fe layered double hydroxides for oxygen evolution Reaction: Impact of Ni/Fe ratio and crystallinity

Abstract

The Oxygen Evolution Reaction (OER), half-reaction of the water-splitting process for hydrogen production, suffers from sluggish kinetics. NiFe materials appeared as interesting catalytic materials for this reaction in alkaline electrolyzers and have been studied, particularly in the form of NiFe Layered Double Hydroxides (LDH). However, the impact of the specificity of the atomic arrangement in the LDH and of its composition on the catalytic efficiency of the material are still unknown. Herein, LDH are synthesized with Ni/Fe ratios from 2 to 4 and different levels of crystallinity to assess their electrocatalytic behavior in 0.1 M KOH. Statistical analysis of the electrochemical results allows to highlight that, while no effect from the atomic ratio is observed, an increase in the crystallinity of the LDH seem detrimental to the catalytic efficiency.