Evaluation of photocatalytic and supercapacitor potential of nickel tungstate nanoparticles synthesized by electrochemical method

Abstract

Nickel tungstate nanoparticles (NiWO₄ NPs) that were synthesized by an electrochemical method under various reaction conditions, namely, different tungstate ion concentrations, voltages, temperatures, and stirring rates, were studied here. These NPs were characterized using FT-IR, XRD, SEM, and thermal analysis techniques. The application of the NiWO₄ NPs as an excellent photocatalyst was investigated via the degradation of methyl orange (MO) under illumination with UV radiation. The maximum conversion of MO reached about 87% after 100 min. Furthermore, the electrochemical properties were investigated using cyclic voltammetry (CV), galvanostatic charge–discharge, electrochemical impedance spectroscopy (EIS) and continuous cyclic voltammetry (CCV) in 3.0 M H₂SO₄ as the electrolyte. The electrochemical investigations revealed that an NiWO₄ electrode displayed enhanced supercapacitive performance, including a specific capacitance of 468 F g⁻¹ at a scan rate of 2 mV s⁻¹. Furthermore, CCV measurements showed that the NiWO₄ electrode retained 102.2% of its initial capacitance after 4000 cycles.