Thermally oxidized porous NiO as an efficient oxygen evolution reaction (OER) electrocatalyst for electrochemical water splitting application

Low-cost and competent electrocatalysts play a key role in an electrocatalytic water oxidation reaction. Herein, we report that readily available bare nickel foam (NF) can be used as conductive substrate and precursor to grow a porous nickel oxide (NiO) using a simple and scalable thermal oxidation method. The obtained NiO supported on NF is used as binder-free electrocatalyst for the oxygen evolution reaction (OER) and its electrochemical properties are evaluated by linear sweep voltammetry (LSV) in 1 M KOH. The porous NiO thin film acts as an efficient electrocatalyst for the OER and achieves a catalytic current density of 10 mA cm−2 at an overpotential of 310 mV with a smaller Tafel slope of 54 mV dec−1. The electrode also shows good durability over 24 h with negligible degradation. This durable and high-performance electrocatalyst can be a competitor to electrocatalysts that consist of costly elements and, require advanced synthesis; the NiO electrocatalyst shows progress towards the replacement of noble metal-based electrocatalysts for the OER.