Photocatalytic properties of Mn-doped NiO spherical nanoparticles synthesized from sol-gel method

Mn-doped NiO (NiO:Mn) nanopowders were synthesized from an inexpensive sol-gel method. The XRD peak profile analysis of NiO:Mn nanopowders confirmed the cubic structure. The spherical nanoparticles of NiO:Mn were evaluated from the SEM and TEM analysis and the grain size decreased as the Mn concentration increased. The average crystallite size decreased from 35.44 nm to 30.5 nm and the bandgap increased from 3.79 eV to 3.95 eV as the Mn concentration increased from 0 wt.% to 4 wt.%. The photocatalytic properties of NiO:Mn nanopowders were measured for the lowest and highest Mn dopant concentrations (Mn: 0 & 4 wt.%) by using the methylene blue dye under UV illumination. The NiO:Mn (Mn: 4 wt.%) nanoparticles showed the highest photocatalytic activity due to the highest activation sites. Therefore, it is revealed that the Mn: 4 wt.% nanoparticles are observed to be more suitable for the photocatalytic activity of methylene blue dye degradation.