Fabrication of CeO2 nanoparticles decorated three-dimensional flower-like BiOI composites to build p-n heterojunction with highly enhanced visible-light photocatalytic performance

Three-dimensional (3D) flower-like CeO2/BiOI heterostructures with different Ce/Bi molar ratio were successfully synthesized via a hydrothermal method using polyvinylpyrrolidone (PVP) as surfactant. The Xray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) results indicate that the CeO2 nanoparticles were successfully loaded on the surface of the flower-like BiOI. The photodegradation experiment demonstrated that the photocatalytic efficiency of CeO2/BiOI samples were higher than that of pure BiOI and CeO2, and CeO2/BiOI heterostructure showed the best photocatalytic performance when the amount of CeO2 located at BiOI up to 15%. The result also exhibits that CeO2/BiOI catalysts possess higher photocatalytic efficiency for Rhodamine B (RhB) and methylene orange (MO) degradation, while it has a slight influence for phenol elimination. Meanwhile, the repeated photocatalytic degradation of RhB experiment reveals excellent photostability. A possible mechanism of photocatalysis was also explored and proposed. Furthermore, loading CeO2 on the surface of BiOI can accelerate the separation rate of photogenerated electron-hole pairs, which is analyzed by photoluminescence (PL) spectroscopy, photocurrent experiments (PC) and electrochemical impedance spectroscopy (EIS). These results exhibit that BiOI can be modified by CeO2 and there exists synergistic effect between CeO2 and BiOI. The present work provides a new means to synthesize heterostructured photocatalyst for environmental remediation. (C) 2017 Elsevier Inc. All rights reserved.