The synthesis of hierarchical Zn-Ti layered double hydroxide for efficient visible-light photocatalysis

Zn-Ti layered double hydroxides (LDHs) with different Zn/Ti ratio have been synthesized by co-precipitation of zinc and titanium salts from homogeneous solution, which were demonstrated as efficient visible-light photocatalysts. Powder X-ray diffraction (PXRD), scanning electron microscope (SEM), high-resolution transmission electron microscopy (HRTEM) and Brunauer-Emmett-Teller (BET) revealed that the resulting Zn-Ti LDHs possess high crystallinity, hierarchical structure as well as large specific surface area (91.96-107.9 m(2) g(-1)). UV-vis diffuse reflection spectroscopy (DRS) confirmed that Zn-Ti LDHs show a broad absorption in visible light region (400-700 nm). With a low band gap of similar to 3.06 eV, the as-prepared Zn-Ti LDHs displayed significant photocatalytic activity for the degradation of methylene blue (MB) under visible-light irradiation (similar to 100% of degradation percentage in 100 min), which is much higher than that of commercial product (Degussa P25). Therefore, this work provides a detailed understanding of semiconductor properties of Zn-Ti LDHs which was unrevealed previously, and demonstrates its potential application in the field of photocatalysis. (C) 2011 Elsevier B.V. All rights reserved.