Photocatalytic conversion of MB dye using Co3O4 QDs‐Ag2MoO4 as an active heterojunction photocatalyst under visible light irradiation

Abstract

Herein, the preparation of Co3O4 QDs‐Ag2MoO4 (AMO) heterojunction was reported by a facile hydrothermal method and characterized by physicochemical methods such as Fourier transformed infrared (FT‐IR), X‐ray diffraction (XRD), field emission scanning electron microscopy (FE‐SEM), energy‐dispersive X‐ray spectroscopy (EDS), transmission electron microscopy (TEM), differential reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), and UV–Vis. The SEM images show that AMO particles and Co3O4 QDs‐AMO have a morphology of 3D‐hexagons and nanosheets accumulated on the surface of 3D‐hexagons with an average of 36 and 28 nm in size, respectively. The Co3O4 QDs‐AMO photocatalyst was used toward the conversion of methylene blue with a removal percentage of 91%, which is 15 times more than pure AMO. The higher photoactivity of Co3O4 QDs‐AMO heterojunction should be assigned to its lower charge recombination rate compared with pure AMO nanoparticles. This heterojunction photocatalyst was removed from the mixture reaction and reused five times without a considerable decline in activity. Furthermore, a postulated mechanism by the hydroxyl radical (°OH) path was proposed.