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

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 degrees C annealing treatment changed the type II SnO/Sn3O4 heterostructures into type I SnO2/Sn3O4 heterostructures; at 700 degrees 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 x 10(-3) min(-1). This highly efficient activity was induced by enhanced charge separation in type II SnO/Sn3O4 heterostructure semiconductors.