Enhanced visible-light-driven photocatalytic performance of AgNbO3 cubes with a high-energy (001) facet

Abstract

AgNbO3 cubes with an exposed high-energy (001) facet were prepared by hydrothermal treatment of Ag2O–Nb2O5–NH4HF2 aqueous suspension. The crystal phase, surface microstructure, and optical properties of the samples were characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, and UV–vis diffuse reflectance spectroscopy. The energy band structure and charge carrier separation efficiency were investigated by photoelectrochemical measurements. In comparison with AgNbO3 powder, whose surface was dominated by a low-energy (114) facet, the AgNbO3 cubes had superior visible-light-driven photocatalytic activity for degradation of tetracycline because of the greater redox ability and more efficient separation of photogenerated electrons and holes. The surface F− ions had no influence on the photocatalytic reactions. Radical trapping experiments demonstrated that the superoxide radical played a decisive role in the photodegradation of tetracycline.