The influence of silver on the properties of cryptomelane type manganese oxides in N2O decomposition reaction

The cryptomelane type oxides were prepared by the redox precipitation technique using Mn(CH3COO)(2) and KMnO4 precursors. Nitrogen sorption, XRD, TEM and TPD of oxygen studies showed changes of the surface, structural and redox properties of the samples upon silver introduction. Samples were investigated in the N2O decomposition reaction. Direct introduction of silver to the synthesis mixture caused partial distortion of regular channel-like structure of the oxides. leading to the decrease of Mn-O bonds strength. As results samples showed slightly better catalytic activity at low temperatures, but were less stable at high temperatures. An introduction of silver by the impregnation method caused the decrease of the surface area of the samples, increase of surface oxygen mobility, leading to the small changes of activity. (C) 2007 Elsevier B.V. All rights reserved.