Optical properties and visible-light-driven photocatalytic activity of Na2Mn2(MoO4)3

Abstract In this paper, Na2Mn2(MoO4)3 doubgyle molybdate was prepared by sol-gel method to investigate the structural, morphological and optical properties. X-ray diffraction analysis showed that Na2Mn2(MoO4)3 crystallizes in the triclinic system in the P 1 ¯ group. The composition and morphology of the compound were checked by energy dispersive spectroscopy coupled with scanning electron microscope. Optical properties were analyzed by UV-Vis diffuse reflectance spectroscopy. The photocatalytic properties were evaluated by the degradation of methylene blue under natural sunlight and compared to Xe and UV lamps. The highest photodegradation efficiency (85.3 %) was obtained for solar irradiation, therefore, Na2Mn2(MoO4)3 can be a potential photocatalyst for the removal of dye wastewater pollution driven by visible-light. The proposed mechanism of photodegradation in water involves creation of hydroxyl radicals and superoxide anions that attack the methylene blue molecules and decompose it to carbon dioxide and water.