Highly Efficient and Stable Water-Oxidation Electrocatalysis with a Very Low Overpotential using FeNiP Substitutional-Solid-Solution Nanoplate Arrays

Abstract

The development of efficient water-oxidation electrocatalysts based on inexpensive and earth-abundant materials is significant to enable water splitting as a future renewable energy source. Herein, the synthesis of novel FeNiP solid-solution nanoplate (FeNiP-NP) arrays and their use as an active catalyst for high-performance water-oxidation catalysis are reported. The as-prepared FeNiP-NP catalyst on a 3D nickel foam substrate exhibits excellent electrochemical performance with a very low overpotential of only 180 mV to reach a current density of 10 mA cm⁻² and an onset overpotential of 120 mV in 1.0 m KOH for the oxygen evolution reaction (OER). The slope of the Tafel plot is as low as 76.0 mV dec⁻¹. Furthermore, the long-term electrochemical stability of the FeNiP-NP electrode is investigated by cyclic voltammetry (CV) at 1.10–1.55 V versus reversible hydrogen electrode (RHE), demonstrating very stable performance with negligible loss in activity after 1000 CV cycles. This present FeNiP-NP solid solution is thought to represent the best OER catalytic activity among the non-noble metal catalysts reported so far.

A substitutional solid solution of iron nickel phosphide (FeNiP) nanoplate arrays is facilely grown on nickel foam as an efficient binder-free electrode for the oxygen evolution reaction (OER). The catalyst demonstrates a very low overpotential of only 180 mV to reach a current density of 10 mA cm⁻² and an onset overpotential of 120 mV in alkaline media.

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