In-situ etching of stainless steel: NiFe2O4 octahedral nanoparticles for efficient electrocatalytic oxygen evolution reaction

Abstract

The development of non-noble metal electrocatalysts for oxygen evolution reaction (OER) has attracted widespread attention in the field of energy. Herein, we report a facile in-situ etching method to convert commercial stainless steel felt (SSF) into NiFe 2 O 4 octahedral nanoparticles as an efficient and robust OER electrode. This preparation method of NiFe 2 O 4 is different from the conventional ones, both nickel and iron elements come from the substrate itself without extra addition of precursors, as well as NiFe 2 O 4 octahedral nanoparticles are self-grown directly on the substrate without binder. The treated SSF shows good water oxidation properties with low overpotential, small Tafel slope, and durable stability at 500 mA cm −2 for 200 h. Moreover, the effect of NaNO 3 in the etchant is studied carefully, which plays the function of removal of chromium and promoting the formation of octahedral nanoparticles, resulting in the enhancement of conductivity and catalytic activity. This study presents a new preparation method for producing NiFe 2 O 4 octahedral nanoparticles with the characteristic of low cost, simple process, wide raw material sources, and favorable OER activity, which demonstrates a good application prospect in the field of large-scale hydrogen production. • Low cost NiFe 2 O 4 octahedral nanoparticles are prepared by a facile in-situ etching of stainless steel felt. • The prepared NiFe 2 O 4 octahedral nanoparticles exhibit high catalytic activity and good long-term stability for OER. • NaNO 3 is proved to have the function of removing Cr and promoting the formation of octahedral nanoparticles.