Effect of La3+ and Ce3+ dopant ions on structural, optical, magnetic, and antibacterial activity of ZnO nanoparticles

Abstract

In the present study, pure and co-doped zinc oxide (ZnO) nanoparticles (Zn 1−2 x La x Ce x O) with atomic percentages x = 0, 0.5, 1.5, 2.5, and 3.5 at% were synthesized via the chemical co-precipitation method. The impact of lanthanum and cerium dopant ions (La 3+ and Ce 3+ ions, respectively) on the structural, morphological, optical, magnetic, and antibacterial activity of the ZnO nanoparticles was investigated. X-ray diffraction patterns reveal the wurtzite hexagonal crystal structure of ZnO nanoparticles (NPs) with the formation of two secondary phases (CeO 2 and La 2 O 3 ) when x =1.5 and 2.5 at% or higher, respectively. La 3+ and Ce 3+ ions show a high impact on the morphology of ZnO NPs, as revealed by transmission electron microscopy analysis. Fourier transform infrared spectroscopy results indicate that La 3+ and Ce 3+ ions induce a red shift in the zinc–oxygen (Zn–O) vibrational mode. The incorporation of La 3+ and Ce 3+ ions into the ZnO matrix showed a remarkable impact on the ZnO NP optical properties. At room temperature, the M–H magnetic hysteresis of the synthesized samples reveal a combination of both diamagnetic and ferromagnetic contributions. The antibacterial properties of the synthesized NPs were also evaluated against six bacterial strains using the agar well diffusion method. The synthesized NPs suppressed the growth of the investigated bacteria with various degrees of toxicity.