Aminopropyl-containing silica-titania mesoporous thin films (Si0.8-xTix(Si(CH2)3NH2)0.2O1.9, 0<x<0.8) were synthesized by a templated sol-gel route. These hybrid materials present a highly ordered cubic mesostructure along all the composition range according to 2D-SAXS. The homogeneity at the atomic level and the aminopropyl group distribution were studied by XANES Si K-edge. Nitrogen and counterion XPS studies in samples with variable Si:Ti amount submitted to varying pH permit to fully assess the acid-base behavior of the aminopropyl surface groups. Speciation of the amino functions located at the pore surface is highly dependent on the surrounding Si(IV) and Ti(IV) centers. This analysis permits to design highly controlled environments by adequately varying the inorganic composition, thus permitting a real teamwork between the three kinds of surface sites that fine-tunes the protonation-deprotonation process. Knowledge of this interplay between organic function and acidic sites on inorganic scaffolds is a powerful tool in the design of organic-inorganic catalysts.

Spectroscopic surface site speciation in mesoporous hybrid thin films: Probing teamwork between Si-OH, Ti-OH and –RNH<sub>2</sub> groups

245th National Meeting (2013)

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Spectroscopic surface site speciation in mesoporous hybrid thin films: Probing teamwork between Si-OH, Ti-OH and –RNH2 groups

Spectroscopic surface site speciation in mesoporous hybrid thin films: Probing teamwork between Si-OH, Ti-OH and –RNH₂ groups