Unveiling Bi-functional potential of ZnMoO4-enriched nanoflakes modified electrodes for efficient photocatalysis and supercapacitors

Abstract

The sol-gel method was used to synthesize pure ZnO and MoO₄@ZnO nanostructures for dual functionality in supercapacitors and photocatalysis. The material properties were examined using photoluminescence spectroscopy (PL), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDX). A PL study showed the presence of an intense peak centering approximately around 405 nm, which is primarily due to the near-band edge emission of ZnO excitonic recombination. XRD confirmed the formation of the ZnMoO₄ crystal system. The SEM showed uniformed nano-flakes which was validated by EDX analysis having typical peaks of Zn, O, and Mo. The synthesized materials were evaluated for bi-functional application, including energy storage and photocatalytic degradation of methylene blue (MB) under solar irradiation. The 5% MoO₄@ZnO nanomaterials showed uniform nanoflakes morphology with remarkable photocatalytic as well as electrochemical excellence. Notably, the 5% MoO₄@ZnO nanomaterial degraded MB about 90.02% within 200 min. Galvanostatic charge discharge (GCD) exhibited an outstanding specific capacitance of 1026 F/g at 1 A/g for 5% MoO₄@ZnO. The columbic efficiency of the 5% MoO₄@ZnO electrode material was assessed until 2000 cycles, that retains its stability about 87%. The cyclic voltammetry was also assessed for the calculation of specific capacitance and energy density. The 5% MoO₄@ZnO depicted excellent capacitance and energy density about 915.62 F/g and 53.72 Wh/kg respectively. This study showed that 5% MoO₄@ZnO is a suitable candidate with the exceptional dual function that can be employed for the development of next-generation energy storage and photocatalysis.

Graphical Abstract