Urchin-like MnOx (Mn3O4/MnO2) hollow nanostructures were successfully synthesized via a simple aqueous synthesis method by using MnCO3 as precursor in basic solution. The reactions performed fast and energy-efficient. The as-prepared MnOx nanostructures extend particle sizes of 1-1.5 mu m with Mn3O4 nanoflakes of 2-3 nm in thickness on the surface. Crystal composition of the MnOx samples varied with reaction temperature and adding sequence of the reactants. Four typical samples were chosen to degrade rhodamine B (RhB) which was as model organic waste. The degradation performed without light sources and H2O2. RhB concentration, pH value and the amount of sample in degradation system were assessed, and light irradiation was detected to be not necessary for the degradation process. The decolorization and degradation rate can reach 97% and 90% in 60 min at pH = 3.0. And cycled degradation experiments under visible light and indoor light revealed that MnOx samples reacted with RhB in acid solution, the reaction speeded the degradation of RhB, and consumption of sample powders also occurred simultaneously in the degradation. (C) 2013 Elsevier B.V. All rights reserved.