Structure, microstructure, optical and photocatalytic properties of Mn-doped ZnO nanoparticles

In this work, Zn_1−xMn_xO samples were synthesized by the hydrothermal method by varying the dopant ratio from x = 0.01 to 0.05 with 0.01 increment. Structural, optical and photocatalytic properties of Mn-doped ZnO were analyzed based on their concentration dependence. Structural behavior of the nanoparticles was studied by X-ray diffraction technique and it was found that Zn_1−xMn_xO samples were hexagonal Wurtzite structure with no secondary phase. The effect of Mn element in Zn_1-xMn_xO composition was clarified by calculating lattice parameters, cell volumes, stress, microstrain, the locality of the atoms dislocation density, displacement of atoms and bond length. SEM images revealed random agglomeration. The band gap and Urbach energies of Zn_1−xMn_xO structures were determined and discussed. Different models were used to calculate refractive index and the refractive index was found in the range of 2.05-2.72. Mn-doped ZnO nanoparticles exhibited lower degradation rate constants (k = 0.0004-0.0009 min⁻¹) than that of pure ZnO (k = 0.0014 min⁻¹). Doping Mn increased the Urbach energy value.