Synthesis of Monodisperse Walnut-Like SnO₂ Spheres and Their Photocatalytic Performances

Novel walnut-like SnO₂ spheres have been synthesized using a one-step hydrothermal reaction with SnCl₂·2H₂O and KOH as raw materials. The morphology, microstructure, and optical properties of the products were characterized by X-ray powder diffraction (XRD), Raman spectrum, scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and ultraviolet-visible (UV-Vis) absorption spectroscopy. The detailed studies revealed that these synthesized spheres are highly monodisperse and have a uniform size of approximately 250 nm. Photocatalytic activity of the prepared SnO₂ spheres was evaluated by the degradation of methylene orange. The synthesized SnO₂ spheres exhibited excellent photocatalytic degradation. In addition, a possible formation mechanism of the walnut-like nanostructures was proposed based on reaction time-dependent experiments.