Hierarchical Bi based nanobundles were self-assembled via an aqueous reduction approach using hydrazine hydrate as reductive agent, and were used as photocatalysts for the degradation of Rhodamine B (RhB) under visible light. PVP molecules were designed as inducing agent to construct the Bi based nanobundles. The as-obtained samples were characterized by X-ray diffraction (XRD), energy dispersive X-ray (EDX), thermogravimetric-differential thermal analyzer (TG-DTA), infrared spectroscopy (IR) and Field emission scanning electron microscopy (FESEM) to get clear information of the crystals. A possible formation mechanism for the interesting architectures was proposed in the paper. The Si based nanobundles exhibited excellent photocatalytic activity and good cycling performance towards photodegradation of RhB under visible light. The pH-sensitive degradation can reach 96% in degradation rate after 90 min. which indicates potential applications of the Si based nanobundles on the degradation of organic pollutants. Degradation mechanism is proposed on the combination of Bi and BiOCl crystals. (C) 2015 Elsevier Inc. All rights reserved.