Improvement of Photocatalytic Activity of ZnO Nanoparticles by Mn Doping in BD71 Degradation

In the present paper, ZnO and manganese doped ZnO (Mn-ZnO) nanoparticles were synthesized via sol-gel method. The prepared samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). XRD results exhibited that Mn was successfully doped in the ZnO structure. SEM images confirmed that the particle size of ZnO and Mn-ZnO samples were in the nanometer ranges. Photocatalytic activity of ZnO and Mn-ZnO nanoparticles on the degradation of direct blue 71 (DB71) under UV light irradiation was investigated. DB71 degradation reached to 82% and 97% after 90 min irradiation using ZnO and Mn-ZnO photocatalysts, respectively. A mechanism for the behavior of the Mn-ZnO nanoparticles and the role of Mn in the enhancement of ZnO photocatalytic activity was proposed. The kinetic studies revealed that the photocatalytic degradation kinetics of DB71 would follow a pseudo first order reaction. Mn-ZnO nanophotocatalyst exhibited appropriate stability for several reuses.