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

AgNbO3 cubes with an exposed high-energy (001) facet were prepared by hydrothermal treatment of Ag2O-Nb2Os-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 pho tocatalytic reactions. Radical trapping experiments demonstrated that the superoxide radical played a decisive role in the photodegradation of tetracycline.