Influence of Mg dopant on photocatalytic properties of Mg-doped ZnO nanoparticles prepared by sol–gel method

Mg-doped ZnO nanoparticles with different Mg contents were synthesized by sol–gel method with subsequently calcination at 600°C for 2 h. The X-ray diffraction results revealed the presence of wurtzite pure ZnO with hexagonal structure in both the undoped and doped samples. The crystallite size of the nanoparticle samples was calculated by Scherrer formula, 92 nm for ZnO and 43 nm for 5 wt % Mg-doped ZnO. Raman spectra of pure and Mg-doped ZnO show peak at 437 cm−1 assigned to ZnO non-polar optical phonon high E2 mode. The size of Mg-doped ZnO characterized by transmission electron microscopy is much smaller than that of pure ZnO. The photocatalytic properties of ZnO and Mg-doped ZnO were investigated by monitoring the methylene blue degradation under UV radiation. For the present study, the 5 wt % Mg-doped ZnO shows the highest photocatalytic activity of 92% within 300 min.