Structure Characterization and Tuning of Perovskite‐Like NaTaO ₃ for Applications in Photoluminescence and Photocatalysis

Abstract

Perovskite‐like NaTaO 3 powders have potential applications in photoluminescence and photocatalysis. Sol–gel, hydrothermal and solid‐state methods were used to synthesize NaTaO 3 powders of different crystalline structures, which were identified by Rietveld refinement simulation of X‐ray diffraction patterns and transmission electron microscopic diffraction. The refinement results show that the sol–gel specimen has a monoclinic phase with a Ta−O−Ta bond angle of 179° while the hydrothermal and solid‐state specimens have an orthorhombic phase with bond angles of 163° and 157°, respectively. By excitation with a 304 nm light source, these NaTaO 3 specimens show photoluminescence emission at ca. 450 nm. The photoluminescence intensity of the specimens had an order solid state >hydrothermal >sol–gel, which is opposite to that of the Ta−O−Ta bond angle. On the other hand, the photocatalytic activity of the NaTaO 3 specimens in water splitting showed the same order as that of the Ta−O−Ta bond angle. This paper directly evidenced that the Ta−O−Ta bond angle affects the separation rate of the photo‐induced charges, as well as that structure tuning of tantalates is achievable and crucial for applications in photoluminescence and photocatalysis.