[en] Highlights: • NaNb_xTa_1−xO₃ perovskites were synthesized via Molten salt method. • The NaNb_xTa_1−xO₃ perovskites exhibited excellent photodegradation efficiencies for RhB. • The NaNb_xTa_1−xO₃ perovskites exhibited excellent performance for the photocatalytic production of hydrogen. NaNb_xTa_1−xO₃ perovskite photocatalysts with cubic microstructures were synthesized by the molten salt method. Furthermore, the photocatalysts were characterized in detail by XRD, SEM, TEM, XPS, PL. SEM results indicated that the added Nb significantly affects the microstructure. XPS results confirmed the presence of the Nb⁵⁺ dopant in NaNb_xTa_1−xO₃. Compared to NaTaO₃, the catalyst doped with Nb significantly affected the photocatalytic production of hydrogen in an aqueous solution and the photocatalytic degradation of RhB under UV light irradiation. NaNb_0.5Ta_0.5O₃ exhibited the best activity for the photocatalytic degradation of RhB as well as excellent performance for the photocatalytic production of hydrogen.