MgO nanoparticles were synthesized by template-free reflux condensation approach. XRD and FTIR confirmed
the formation of single phase MgO exhibiting cubic crystal structure. SEM and TEM analysis revealed the formation
of MgO nanoflakes. The optical band gap of MgO nanoparticles estimated from UV DRS was in the range
5.40–5.45 eV. PL spectra of MgO nanoparticles showed visible emissions due to the formation of defects in the
band gap region of MgO. Synthesized MgO nanoparticles exhibited appreciable photocatalytic activity for the
degradation of methyl orange and methylene blue dyes under UV light irradiation. Results demonstrated that
the origin of photocatalytic activity in MgO arises due to the existence of high concentration of native defects
on the surface of MgO.