Interface modulation of a layer-by-layer electrodeposited FexCo(1−x)P/NiP@CC heterostructure for high-performance oxygen evolution reaction

Abstract

The search for an oxygen evolution reaction (OER) electrocatalyst with much improved performance is ongoing. The development and design of highly active, noble-metal free and low cost electrocatalysts is of great importance for the realization of renewable energy. Herein, a carbon cloth (CC) supported iron doped cobalt phosphide, layered-with a nickel phosphide film (Fe_0.45Co_0.55P/NiP@CC) was synthesized with a simple two step electrochemical deposition technique at room temperature. This free-standing Fe_0.45Co_0.55P/NiP@CC heterostructure presents superior OER performance in an alkaline media, with a strikingly low onset potential of 1.26 V and achieving a current density of 10 mA cm⁻² at an overpotential of 247 mV vs. RHE in 1 M KOH, outperforming the state of the art RuO₂ electrocatalyst. A Tafel slope of 56 mV dec⁻¹ and excellent long-term stability was achieved. Purposefully using NiP as a scaffold to in situ generate an active oxyhydroxide (NiOOH) OER catalyst on the surface of the electrode and interface coupling between the two layers provides numerous active sites and a synergistic effect to bring forth the profoundly enhanced performance of Fe_0.45Co_0.55P/NiP@CC electrode.