Hydrothermal synthesis of zinc molybdates (α-ZnMoO4) nanoparticles and its applications of supercapacitor and photocatalytic performances

Abstract

The rational construction and design of nanostructured materials have a significant impact on the fabrication of high-performance electrode materials, which have attracted considerable interest in an effort to enhance the reliability and efficiency of energy storage devices. In this study, the α-ZnMoO4 nanoparticles were successfully prepared by facile hydrothermal method and the influence of various hydrothermal reaction times on structural, morphological, optical and electrochemical properties were studied. XRD analysis illustrated that α-ZnMoO4 nanoparticles exhibited anorthic crystal structure and the average crystallite size was 42 nm. FESEM images changed from a cubic structure to plate-like structures depending on reaction times. HRTEM analysis revealed that prepared sample showed a plate-like structure and the SAED pattern exhibited a polycrystalline nature. The FTIR spectrum confirmed the presence of vibrational molecules in α-ZnMoO4 nanoparticles. The BET and XPS measurements showed the α-ZnMoO4 nanoparticles were mesoporous and had Zn2+ and Mo6+ oxidation states, respectively. From UV–Visible spectra, a better spectral selectivity region was observed at higher reaction times, and the bandgap values were decreased from 2.73 to 2.48 eV. In photocatalytic studies, RhB dye was used as an organic pollutant and achieved a degradation efficiency of 85 % at an optimized reaction time of 24 h. For electrochemical performances, the prepared electrode material showed maximum specific capacitance values of 165 F g−1 and 110 F g−1 for cyclic voltammetry and galvanoststic charge-discharge analysis, respectively.