A simple geometrical model is applied to predict the thickness of mesoporous shells over monodisperse spherical particles. As an example, mesoporous Ti-silicate nearly monodisperse particles with the "core-shell" structure, synthesized via the one-pot procedure are considered. The unique features of the materials are orientation of mesopores perpendicularly to the surface of non-porous cores and uniformity of mesoporous shells structure and thickness. This allows considering these materials as interesting catalysts for partial oxidation of bulk organic molecules with hydrogen peroxide. (C) 2009 Elsevier B. V. All rights reserved.