Biosynthesis of Dy₂O₃ nanoparticles using Piper Retrofractum Vahl extract: Optical, structural, morphological, and photocatalytic properties

Biosynthesis of nanoparticles has attracted much attention due to its environmental safety, cost-effectiveness, and straightforward fabrication. For the first time, Piper Retrofractum Vahl Fruits Extract (PRFE) was used as a low-cost natural hydrolyzing agent in the synthesis of Dysprosium Oxide (Dy₂O₃). The optical, structural, morphological, and photocatalytic properties of Dy₂O₃ nanoparticles were observed by various characterization methods such as FT-IR, XRD, UV-Vis DRS, FESEM-EDS, and TEM. The absorption bands of the C-N and N-H functional groups were revealed by FT-IR analysis. Alkaloid compounds of PRFE are assigned to the hydrolyzing agents. Furthermore, the XRD and EDS analyses confirmed the presence of Dy₂O₃ without impurities. Morphological characterization by FESEM showed that Dy₂O₃ nanoparticles were in a spherical shape, while the particles size was obtained to be 20-30 nm validated by TEM measurement. The optical bandgap of Dy₂O₃ was 4.8 eV, which is active in the UV region. Dy₂O₃ nanoparticles showed a remarkable photocatalytic activity, which has an efficiency of 92.76%, with a small amount of catalyst loading for malachite green degradation under UV light irradiation within 120 min. The trapping experiment proved that h⁺ is the predominant reactive species in the photodegradation reaction. Ultimatelly, this work presents a superior biosynthesized Dy₂O₃ photocatalyst, which demonstrates high stability in four consecutive cycles.