a b s t r a c tLayered birnessite-type manganese oxides (Na-OL-1) were prepared via a redox reaction involving MnO 4 − and Mn 2+ under markedly alkaline conditions. According to the XRD analysis, the resulting material exhibited a well-crystallized octahedral layer (OL) structure with several different phases, including ␤-MnOOH, ␣-MnOOH and ␥-Mn 3 O 4 . The catalyst was highly effective for the decolorization and degradation of methylene blue (MB) in the presence of H 2 O 2 at neutral pH. The tested MB was completely decolorized in Na-OL-1 suspension by the fraction dosing of H 2 O 2 (556.5 mM at the beginning and then 183.8 mM at 40 min). Based on the studies of electron spin resonance and the effect of radical scavengers, the 1 O 2 and O 2 •− were the main reactive oxygen species (ROS) in the reaction. It was found that both oxygen and ROS were generated from the decomposition of H 2 O 2 in Na-OL-1 suspension, wherein the decomposition pathways were proposed. The generation of H 2 O 2 in Na-OL-1 suspension at air atmosphere indicated that the existence of multivalent manganese oxides greatly enhanced the interfacial electron transfer, leading to the high activity of Na-OL-1.