Preparation of cerium-doped ZnO hierarchical micro/nanospheres with enhanced photocatalytic performance for phenol degradation under visible light

Cerium-doped ZnO hierarchical micro/nanospheres (Ce/ZnO) were prepared using a facile and surfactant-free chemical precipitation method. The as-synthesized products were characterized by X-ray diffraction, field-emission scanning electron microscopy, energy-dispersive:X-ray spectroscopy, transmission electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, UV-visible diffuse reflectance spectroscopy and photoluminescence spectroscopy. The results showed that the as-synthesized products were well-crystalline and accumulated by large amount of interleaving nanosheets. It was also observed that the Ce doping led to red shift in the absorption band and improved the visible light absorption ability of the catalysts. Under visible light irradiation, the Ce/ZnO exhibited much higher photocatalytic activity than those of pure ZnO and commercial TiO2 for the degradation of phenol. The enhanced photocatalytic performance of Ce/ZnO can be attributed to the effective separation of charge carriers. Radical scavenger experiments and terephthalic acid-photoluminescence probing test revealed that hydroxyl radical played a pivotal role for the phenol degradation. Morebver, the Ce/ZnO showed no significant loss of the photocatalytic activity after four repeated degradation experiments, showing great potential for practical applications in environmental remediation. (C) 2015 Elsevier B.V. All rights reserved.