Montmorillonites modified with carbon deposits were reported to be promising catalysts of NO reduction with ammonia (SCR). The influence of different preparation methods on structural, textural and sorption properties were discussed. Three preparation methods were considered, differing in the pretreatment of the clay preceding the introduction of carbon precursor (polymer soluble in water). The structure was studied by XRD, texture by sorption of argon, benzene and carbon tetrachloride and surface composition by XPS. The obtained nanocomposites had different textural properties, depending on pretreatment. XPS, TPD and textural data suggest different mechanisms of formation of nanocomposites on untreated and acidic pretreated clays. The introduction of carbon deposits influenced hydrophilic properties. The number of ammonia sites changed after each preparative step: acidic pretreatment, pillaring and the formation of carbon deposits. (C) 2004 Elsevier B.V. All rights reserved.