One-step corrosion method for preparing Ni–Fe layered double hydroxide on nickel foam: Importance of the iron valence state

Abstract

A facile chloride corrosion method was adopted to synthesize Ni−Fe layered double hydroxide (LDH) materials on Ni foam. Ni–Fe LDH catalysts with varying oxygen evolution reaction (OER) performance were obtained by using different iron salts. The reasons for differences in the OER activity were investigated through experiments and characterizations. Structural characterization results showed that Fe3+ salts generated Ni–Fe LDH on nickel foam (NF), and FeOOH was additionally obtained by Fe2+ salts. Compared with NiFe/NF prepared with ferrous salts precursors, NiFe/NF catalysts produced using ferric salts exhibited markedly enhanced OER performance, presenting lower overpotentials of approximately 290 mV to deliver a current density of 100 mA cm−2 and lower Tafel slopes of approximately 96 mV dec−1 in 1.0 M KOH.