Enhancement in the Structural, Electrical, Optical, and Photocatalytic Properties of La 2 O 3 -Doped ZnO Nanostructures.

A lanthanum oxide (La 2 O 3 )-ZnO nanostructured material was synthesized in the proposed study with different La 2 O 3 concentrations, 0.001 g to 5 g (named So to S7), using the combustion method. X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transformation infrared spectroscopy (FT-IR) were utilized for investigating the structure, morphology, and spectral studies of the La 2 O 3 - ZnO nanomaterials, respectively. The results obtained from previous techniques support ZnO's growth from crystalline to nanoparticles' fine structure by changing the concentrations of lanthanum oxide (La 2 O 3 ) dopants in the host matrix. The percentage of ZnO doped with La- influences the ZnO photocatalytic activity. SEM analysis confirmed the grain size ranged between 81 and 138 nm. Furthermore, UV-Vis diffuse reflectance spectroscopy was performed to verify the effects of La 2 O 3 dopants on the linear optical properties of the nano-composite oxides. There was a variation in the energy bandgaps of La 2 O 3 -ZnO nanocomposites, increasing the weight concentrations of lanthanum dopants. The AC electrical conductivity, dielectric properties, and current-voltage properties support the enactment of the electrical characteristics of the ZnO nanoparticles by adding La 2 O 3 . All the samples under investigation were used for photodegradation with Rhodamine B (RhB) and Methylene Blue (MB). In less than 30 min of visible light irradiation, S4 (0.5 g) La 2 O 3 -ZnO reached 99% of RhB and MB degradation activity. This study showed the best photocatalytic effect for RhB and MB degradation of 0.13 and 0.11 min -1 by 0.5 g La 2 O 3 -ZnO. Recycling was performed five times for the nanocatalysts that displayed up to 98 percent catalytic efficiency for RhB and MB degradation in 30 min. The prepared La 2 O 3 -ZnO nanostructured composites are considered novel candidates for various applications in biomedical and photocatalytic studies.