Green synthesis of semiconductor nanoparticles (ZnO, CuO, and SnO2) using Physalis philadelphica peel extract: characterization and photocatalytic studies on five organic dyes

Abstract

This study employed a green methodology for synthesizing oxide semiconductor nanoparticles (NPs) using a natural extract from husk tomato (Physalis philadelphica) as a reductant and stabilizing agent. The NPs produced include ZnO, SnO₂, and CuO. Characterization was carried out using various techniques to identify the physical, optical, and chemical properties of the synthesized NPs; ultraviolet–visible spectroscopy (UV–Vis) was employed to determine absorption bands and calculate the band gaps of 2.95, 2.7, and 1.9 eV for the semiconductors (ZnO, SnO₂, and CuO). Fourier Transform Infrared (FT-IR) spectrum shows the metal–oxygen bond characteristics of the materials analyzed. The X-ray diffraction (XRD) diffractogram indicates the formation of hexagonal zincite (ZnO), tetragonal cassiterite (SnO₂), and monoclinic tenorite (CuO) structures, and crystallite sizes of 12.777, 15.451, and 39.915 nm, respectively. TEM and SEM were utilized to obtain information on surface, shape, and size; energy-dispersive X-ray spectroscopy (EDX) confirmed the chemical composition. Finally, photocatalytic studies were conducted to investigate the degradation of five organic dyes: methylene blue (MB), rhodamine B (RhB), malachite green (MG), methyl orange (MO), and congo red (CR). The results indicated that over a 180-min period, these dyes underwent degradation through a photocatalytic process, with ZnO, SnO₂, and CuO NPs serving as photocatalysts. This demonstrates that the synthesized NPs possess excellent photocatalytic properties.