High-efficiency photocatalytic activity of type II SnO/Sn3O4 heterostructures via interfacial charge transfer

Abstract

Flower-like hollow microspheres were synthesized on a large scale using a one-step hydrothermal route. The as-prepared products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and UV-vis diffuse reflectance spectroscopy. The results showed that the shells of the hollow microspheres were composed of numerous type II SnO/Sn₃O₄ heterostructures. A 500 °C annealing treatment changed the type II SnO/Sn₃O₄ heterostructures into type I SnO₂/Sn₃O₄ heterostructures; at 700 °C, the products were pure SnO₂ semiconductors. A photocatalytic degradation test showed that the highest efficiency degradation of rhodamine B (RhB) was obtained using type II SnO/Sn₃O₄ heterostructure semiconductors with a degradation rate constant of 2.3 × 10⁻³ min⁻¹. This highly efficient activity was induced by enhanced charge separation in type II SnO/Sn₃O₄ heterostructure semiconductors.