Synthesis, characterization, and photocatalytic activity of sol–gel prepared Mg/ZnO nanoparticles

Abstract

In this study, ZnO nanoparticles with different Mg contents and calcination temperatures were synthesized by the sol–gel method. The photocatalytic activity of the synthesized nanoparticles was investigated in the photocatalytic degradation of Rhodamine B. The products were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX)-mapping, scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance spectroscopy (DRS), and Brunauer–Emmett–Teller (BET) techniques. The XRD results showed that the doped nanoparticles had the same crystal structure as the pure ZnO. The EDX and mapping findings indicated the existence of Mg in the doped sample. SEM and TEM analysis showed the spherical shape and uniform-size distribution of the nanoparticles. Based on DRS spectra, the band gap energy value of 2.0 wt% Mg doped ZnO was 3.26 eV, which was larger than the ZnO nanoparticles’ band gap energy. Using BET analysis, the surface areas of ZnO and 2.0 wt% Mg/ZnO were calculated to be 14.9 and 22.5 m² g⁻¹, respectively. The results of the photocatalytic activity indicated that Mg/ZnO was more active than pure ZnO photocatalyst due to its higher surface area and larger band gap energy. Maximum photocatalytic activity was achieved for Mg/ZnO nanoparticles with 2.0 wt% Mg and at the calcination temperature of 400°C.

Keywords:

• Heterogeneous photocatalysis
• Mg/ZnO nanoparticles
• Rhodamine B
• Sol–gel

Acknowledgments

The authors would like to thank the financial support of Tabriz Branch, Islamic Azad University and the Iranian Nanotechnology Initiative Council.