Three MnO (x) -SnO2 catalysts were successfully prepared by hetero-redox, homo-redox and common hydrothermal methods. NO adsorption and desorption were performed to investigate the NO (x) storage capacity at 100 A degrees C. All the samples showed good performances on NO (x) storage, especially the sample prepared by homo-redox hydrothermal method. The XRD, BET, TPR, XPS measurements were used to characterize the structure of the catalysts. The results revealed that the oxidation state of Mn and the defect oxygen species could be responsible for the high NO (x) storage capacity.