Effects of Mn on the magnetic and optical properties and photocatalytic activities of NiO nanoparticles synthesized via the simple precipitation process

Pure and Mn doped NiO nanopartides have been successfully synthesized via the simple precipitation process. The XRD and TEM studies have confirmed that the prepared NiO nanoparticles sizes decreased with the manganese insertion into nickel oxide. The observed antiferro to superpara and ferromagnetic transition on Mn doping in NiO is understood on the basis of Mn occupying Ni sites, and breaking the translational symmetry of the parent antiferromagnetic correlation. The measured band gap energies (E-g =3.78, 3.81,3.84 and 3.90 eV) increased with decreasing particles size, which indicated the quantum confinement effect. The broad visible emission at 527 nm originates from the deep levels of the prepared NiO nanoparticles and is due to the presence of V-o and Ni-(in) defects. The photocatalytic degradation of the methyl orange dye was studied for the prepared pure and doped samples, and the mechanism has been discussed. (C) 2015 Elsevier B.V. All rights reserved.