Mn3O4@ZnO Hybrid Material: An Excellent Photocatalyst for the Degradation of Synthetic Dyes including Methylene Blue, Methyl Orange and Malachite Green

In this study, we synthesized hybrid systems based on manganese oxide@zinc oxide (Mn3O4@ZnO), using sol gel and hydrothermal methods. The hybrid materials exhibited hierarchical morphologies and structures characterized by the hexagonal phase of ZnO and the tetragonal phase of Mn3O4. The hybrid materials were tested for degradation of methylene blue (MB), methyl orange (MO), and malachite green (MG) under ultraviolet (UV) light illumination. The aim of this work was to observe the effect of various amounts of Mn3O4 in enhancing the photocatalytic properties of ZnO-based hybrid structures towards the degradation of MB, MO and MG. The ZnO photocatalyst showed better performance with an increasing amount of Mn3O4, and the degradation efficiency for the hybrid material containing the maximum amount of Mn3O4 was found to be 94.59%, 89.99%, and 97.40% for MB, MO and MG, respectively. The improvement in the performance of hybrid materials can be attributed to the high charge separation rate of electron-hole pairs, the co-catalytic role, the large number of catalytic sites, and the synergy for the production of high quantities of oxidizing radicals. The performance obtained from the various Mn3O4@ZnO hybrid materials suggest that Mn3O4 can be considered an effective co-catalyst for a wide range of photocatalytic materials such as titanium dioxide, tin oxide, and carbon-based materials, in developing practical hybrid photocatalysts for the degradation of dyes and for wastewater treatment.