The effect of zirconium and niobium oxidic species on platinum dispersion in 1%Pt/Nb,Zr-containing MCM-41

Platinum was deposited on MCM-41 mesoporous supports that contained niobium and/or zirconium introduced either at the stage of mesoporous material synthesis or after synthesis by impregnation. It has been found that zirconium introduced during synthesis of MCM-41, influenced particle size of the material to a considerable extent and this, in turn, resulted in quite a high dispersion of platinum on the support. Such an effect was not observed in the case of niobiosilicate material. Niobium affected dispersion. when it was introduced to silicate MCM-41 by impregnation. Niobium oxidic species formed on mesoporous material surface, due to their strong interaction with platinum, prevented from sintering of the latter during reduction, thus increasing platinum dispersion. (C) 2008 Elsevier B.V. All rights reserved.