Mn-doped ZnO: role of morphological evolution on enhanced photocatalytic performance

Recently, zinc oxide (ZnO) has attracted much interest, owing to its efficient photocatalytic applications. Herein, we report the synthesis of pristine and Mn-doped ZnO photocatalyst with different nanostructures. The samples were synthesized via simple and low cost co-precipitation method. The synthesized samples were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX) spectroscopy, UV-visible diffuse reflectance spectroscopy (UV-DRS) and photoluminescence (PL) studies. The structural analyses revealed the formation of well crystalline nano photocatalyst. Interestingly, doping has altered the morphology of the pristine ZnO significantly from the randomly oriented flakes like structure to rice like structures. The doping of Mn has been established via EDX analyses. Incorporation of Mn has enhanced the photon absorption towards visible region along with the formation of some favorable defect states. The photocatalytic performance of Mn doped ZnO showed superior activity than the pristine ZnO. The enhanced photocatalytic performance of the doped sample can be ascribed to the presence of Mn into the ZnO lattice. Furthermore, doping results into the formation of inter band states which make the easy transfer of excited electrons from the valence band to the conduction band along with efficient electron-hole pair separation. Moreover, the morphological evolution of ZnO due to the doping may also play a vital role in enhancing the photocatalytic performance of the doped sample.