The electrical, optical, and photocatalytic properties of Mg-doped ZnO nanoparticles synthesized via solution combustion

Abstract Zn 1- x Mg x O ( x = 0, 0.03, 0.05, 0.07) nanoparticles were synthesized via solution combustion. Structural analysis confirmed a hexagonal wurtzite structure (space group P 6 3 mc). Crystallite sizes, calculated using the Debye–Scherrer formula, ranged from 55 to 75 nm. Fourier transform infrared spectra exhibited characteristic absorption peaks of wurtzite ZnO at 424 and 514 cm −1 , while Raman spectra revealed optical phonon modes associated with the wurtzite phase. Morphological and elemental analyses were performed using scanning electron microscope along with energy dispersive X-ray spectroscopy. Ultraviolet diffuse reflectance spectroscopy showed a blue shift in the band gap energy, increasing from 3.25 to 3.34 eV with higher Mg doping. Photoluminescence emission spectra indicated interstitial defects and oxygen vacancies, which significantly affected the electrical and optical properties. Impedance analysis revealed the presence of grains and grain boundaries, with total conductivity decreasing from 7.64 × 10 −8 S cm −1 to 1.03 × 10 −8 S cm −1 as Mg content increased. Mg-doped ZnO nanoparticles demonstrated improved charge carrier separation, enhancing photocatalytic activity. Photocatalytic studies on methylene blue (MB) dye degradation under UV light showed that Zn 0.93 Mg 0.07 O exhibited the highest photodegradation rate of 46 % after 180 min of irradiation.