Novel functionalized of ZnO with Sm3+, La3+, and Sr2+/ZnO single and tri-doped nanomaterials for photocatalytic degradation: synthesis, DFT, kinetics

Abstract

Pure zinc oxide, single-doped zinc oxide as 2 wt% of Lanthanum as (La DZ NPs), 2 wt% of Samarium (Sm DZ NPs), and 2 wt% of Strontium as (Sr DZ NPs), and tri-doped (Sm, La, Sr, T DZ NPs) were synthesized with a hydrothermal method. Additionally, these nanomaterials are used as an effective photocatalytic for the degradation of Reactive Red 43. These nanomaterials’ optical, particle size distribution, structural properties, and morphology were analyzed using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), ultraviolet (UV) light, photoluminescence (PL), scanning electron microscopy (SEM) and energy-dispersive X-ray (XPS), transmission electron microscopy (TEM), and the point of zero charges (pHpzc). Molecular modeling simulation was calculated using density functional theory (DFT) to confirm some characterization. Moreover, these studies showed the crystal structure parameters changed with doped nanomaterials, and the experimental band gap fit theoretical calculation and demonstrated the reason for the widening of the band gap. An enhancement in the surface area of Sr DZ NPs recorded high value (SBET = 37.43 m2/g) indicated that it can be used as an efficient photocatalyst, where Sr DZ NPs showed the best photodegradation % of Reactive Red 43 dye with 93.43% compared to PZ (72.88%), La DZ NPs (52.54 3%), Sm DZ NPs (31.99%), and La, Sm, Sr T DZ NPs (20.55%). Furthermore, the pseudo-first-order kinetic model better fits the R2 values. Finally, the mechanism of degradation has been related to electronic configuration. In addition, the recyclability showed stability of nanomaterials under UV irradiation. Graphical abstract