Cobalt-Doped Nickel Hydroxide on Polyaniline-Decorated Nickel Foam for Enhanced Performance of the Oxygen Evolution Reaction

In this research, cobalt-doped Ni(OH)₂ on a PANI-decorated NF substrate is prepared via an electrochemical method. The surface characteristics, roughness, chemical composition, and crystalline structure of the prepared materials are described using scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD), in that order. Further, optical characterization techniques of attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and Raman spectroscopy are used for confirmation of the polymerization of PANI. The results reveal that PANI and bimetallic oxide/hydroxide agglomerate on the bare NF's flat skeleton. The electrocatalytic performance of Co-Ni(OH)₂/PANI-NF for the oxygen evolution reaction (OER) in alkaline media is carried out, and it demonstrates outstanding electrocatalytic activity, exhibiting an overpotential of 180 mV@20 mA cm^-2 with a Tafel slope of 62 mV dec^-1. The TOF (10^-2) value is determined to be 2.49 s^-1 at 1.58 V, highlighting the elevated intrinsic activity of Co-Ni(OH)₂/PANI-NF in catalyzing the OER. The stability testing using chronoamperometry (CA) for 24 h to accomplish 100 mA cm^-2 and cyclic voltammetry (CV) for 200 cycles with a scan rate of 5 mV s^-1. The results demonstrate that the material maintains its electrochemical performance and structural integrity even after prolonged exposure to these conditions. These findings highlight that Co-Ni(OH)₂/PANI-NF is an effective and promising electrocatalytic material for the OER, potentially advancing the efficiency of hydrogen production through water electrolysis.