Enhanced water oxidation reaction by binder-free nickel oxide nanorod arrays electrocatalyst

Abstract

Water splitting for hydrogen generation is one of the auspicious technologies for the sustainable resource storage and designing low cost electrocatalysts with high activity and is considerable to ameliorate the slow kinetic process of oxygen evolution reaction (OER). Accordingly, in this work, an experimental investigation for the improved water oxidation reaction based on the nickel oxide (NiO) nanorod arrays structure electrocatalyst is performed for the hydrogen production reaction. In this context, a highly efficient functional electrocatalyst is developed by morphology engineering for the growth of NiO nanorod arrays on Ni foam (NF) substrate (NiO–NF electrocatalyst) as an anode. The electrode is prepared by utilizing the hydrothermal method under the optimized experimental conditions (heating temperature of 100 °C and reaction time of 12 h in atmosphere). The electrochemical performance of the fabricated electrode is studied in an alkaline solution of 1.0 M KOH, and the obtained results revealed that only +350/+450 mV with/without iR-Correction is required to reach a current density of 100 mA cm−2, showing an effective electrocatalyst for water oxidation. The low charge-transfer resistance of the electrocatalyst (∼ 5 Ω) indicates favorable catalytic dynamics during OER. Notably, the electrocatalyst demonstrates outstanding durability during rigorous oxygen evolution testing in 1.0 M KOH for 100 h with ∼ 98% Faradaic efficiency. Additionally, the enhanced efficiency of the developed electrode for water splitting can be related to the improved morphology of the nanorod structure, high ordered array architecture, hydrophilic feature, and high adhesion of NiO nanorod arrays on the NF substrate.