Synthesis of Hexagonal BaTa2O6 Nanorods and Influence of Defects on the Photocatalytic Activity

Hexagonal barium tantalate (BaTa2O6) nanorods were synthesized by a hydrothermal method based on the reaction of concentrated Ba(OH)2 solution and Ta2O5. BaTa2O6 samples show a uniform cylindrical structure with diameters of 5−30 nm and the lengths of 50−200 nm. The formation of BaTa2O6 nanorods follows a dissolution−recrystallization mechanism and is governed by hydrothermal temperature and time. BaTa2O6 nanorod samples prepared at 270 °C for 72 h have exhibited the highest photocatalytic activity in the degradation of Rhodamine B (RhB) in aqueous solution under UV radiation. Hydrogen-related defects were detected in BaTa2O6 nanorods, which originate from the oxygen octahedron. The number of defects was dependent on the hydrothermal temperature, and the photocatalytic activities of BaTa2O6 nanorods increase with the decrease of defect amounts. On the basis of the experiment results, the difference in photocatalytic activities for samples is mainly caused by lattice defects, which can act as inactivation centers.