Core shell ZnO-MnO 2 nanocomposites for dye degradation and DFT simulation

Abstract To promote the photogeneration of charge–carriers separation, the ZnO/MnO2 nanocomposites have been efficiently synthesized via simple hydrothermal process and tested as photocatalyst for dye degradation. The samples of ZnO, MnO2, and ZnO/MnO2 nanocomposites have been investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis diffuse reflection spectroscopy and photoluminescence spectra (PL). The photocatalytic activity of the ZnO/MnO2 prepared using 10 mg is much higher than that of ZnO or MnO2 as demonstrated by optical and photoluminescence measurement. The improvement of Methyl Orange (MO) photodegradation compared with pure ZnO and MnO2 is originated from the high surface area, the efficient sun light absorption and the excellent charge carrier’s separation of the ZnO/MnO2 photocatalyst. The DFT simulations of ZnO and MnO2 have determined the electronic origin of structures properties and demonstrate that photocatalytic activity is attributed to the electrons transition between valence and conduction bands of materials.