Enhanced photocatalytic of N/F-doped-NaTaO₃ photocatalyst synthesized by hydrothermal method

N/F-doped NaTaO₃ powders were synthesized via a hydrothermal method at 160 °C. The influences of N/F co-doping on the crystal structure, morphology and photocatalytic properties of the NaTaO₃ powders were investigated systematically. Rietveld refinement of X-ray diffraction data confirm that the nanoparticles of pure NaTaO₃ have orthorhombic structures with Pc21n:bca and Ta₂O₅ can be obtained by doping N/F molar ratio (NaOH/NH₄F ≤ 1) with the orthorhombic P2 mm:cab space group. The NaTaO₃ powders are transformed from orthorhombic Pc21n:bca into monoclinic P2/m:b space group with the NaOH/NH₄F molar ratio (NaOH/NH₄F > 1). The well-defined cubic block NaTaO₃ single-crystalline particles with the size of 0.5 μm are determined using TEM and grow preferentially along (101) and (010) crystal planes. The photocatalytic activities were evaluated by the degradation of Rhodamine B under UV-light irradiation. The possible mechanism is proposed to discuss the enhanced photocatalytic activity based on the increasing separation efficiency of photoinduced charge. The results illustrate that the obtained monoclinic N/F-NaTaO₃ (NaOH/NH₄F = 1.5/1.0) powder exhibits the best photocatalytic activity with the UV-light irradiation for 210 min.