Facile Hydrothermal Synthesis of Sodium Tantalate (NaTaO3) Nanocubes and High Photocatalytic Properties

Nanosize NaTaO3 photocatalysts have been synthesized by a single-step hydrothermal method. The product was characterized using various techniques, such as X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), and a volumetric adsorption method (Brunauer−Emmett−Teller (BET)). The influence of reaction temperature and time, as well as alkaline concentration, on the morphology of the photocatalysts was investigated. The results showed that pure-phase NaTaO3 could be synthesized in a NaOH solution of 0.5 mol/L concentration at 140 °C for 12 h. This process was dominated by a dissolution/precipitation mechanism, in which the growth mechanism of the NaTaO3 nanoparticles was also discussed based on its crystal structure. The NaTaO3 nanostructures show a higher photocatalytic activity in the degradation of Safranine T dye and gaseous formaldehyde than those of solid-state-reacted counterparts and P25, due to their perfective crystallinity and larger surface areas.