Bi12TiO20 complex architectures (BiT) with flower-, spindle- and jujube-like shapes, were prepared through a facile template-free hydrothermal process, by controlling the reaction parameters, such as temperature, reagent concentration, and reaction time. Within the hydrothermal temperature range from 150 to 200 degrees C, the morphology transformed progressively from microjujube to microflowers consisted with nanospindles. A possible growth mechanism for BiT architectures was proposed to explain the transformation of nanoparticles to microflowers via an Ostwald ripening mechanism followed by self-assembly. Most importantly, much higher photocatalytic activities of BiT spindle-like structures modified with 0.5% polyaniline (PANI) via a simple chemisorption approach in comparison with unmodified BIT were obtained for the degradation of Rhodamine B (RhB) solution under visible-light irradiation (lambda > 420 nm). Furthermore, an enhanced photocatalytic performance for RhB degradation was also observed with the assistance of a small amount of H2O2. The reason could be ascribed to the synergic effect between PANI and BIT, which promoted the migration efficiency of photogenerated electron-hole on the interface of PAN! and BIT, demonstrating that PANI/BiT architecture is a promising candidate as a visible light photocatalyst. (C) 2011 Elsevier B.V. All rights reserved.