Synthesis, characterization, and enhanced photocatalytic properties of NiWO4 nanobricks

Abstract

Brick shaped nanoparticles of nickel tungstate (NiWO₄) were synthesized magnificently using the molten salts process at 500 °C. Powder X-ray diffraction (PXRD) and electron microscopy measurements were carried out to investigate the phase purity, crystal structure, and morphology (size and shape) of the NiWO₄ nanobricks (diameters of ∼20 nm). The BET surface area of the NiWO₄ nanobricks was found to be ∼25 m² g⁻¹. The optical properties of the NiWO₄ nanobricks demonstrate a direct band gap of 2.95 eV. Thereupon, the photocatalytic activities of the NiWO₄ nanobricks have been investigated for the degradation of methylene blue (MB) dye in neutral and basic media under solar light irradiation (SLI). The NiWO₄ nanobricks show significant enhancement in the photo-degradation of MB dye solution in alkaline (∼100% in 50 minutes) and neutral media (∼80% in 330 minutes) as compared to bulk NiWO₄ and previous reports of metal tungstate. ESI mass spectrometry was also carried out to confirm the photocatalytic degradation of dye molecules.