The controllable synthesis of tantalate K1.9Na0.1Ta2O6 center dot 2H(2)O has been successfully achieved by a two-step technique, namely, the molten salt and hydrothermal methods, at a low temperature. By simply varying the KOH concentration in the hydrothermal process, K1.9Na0.1Ta2O6 center dot 2H(2)O particles with spherical, cuboctahedral, and durian-like morphologies were synthesized. The photocatalytic activity of the obtained samples for the degradation of rhodamine B was studied under ultraviolet light, which indicates that the photocatalytic properties of the samples are highly dependent on their morphologies. The K1.9Na0.1Ta2O6 center dot 2H(2)O nanospheres, with rough surfaces and the highest specific surface area, exhibit the best performance. The present work provides a unique approach for the controlled synthesis of tantalate photocatalysts, which are difficult to achieve through other synthetic approaches. (C) 2015, Dalian Institute of Chemical Physics, Chinese Academy of Sciences.