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RESEARCH PRODUCT

Selective Surface Modification of SiO2−TiO2 Supports with Phosphonic Acids

Aurelian F. PopaMichel GranierVincent LafondAlain DereuxP. Hubert MutinLaurent Markey

subject

chemistry.chemical_classificationAuger electron spectroscopyAqueous solutionGeneral Chemical EngineeringInorganic chemistryGeneral ChemistryPolymerCatalysischemistryMaterials ChemistrySurface modificationMixed oxideSelectivityMesoporous material

description

The selective surface modification by phosphonic acids of SiO2−TiO2 supports at the micrometer and molecular scale was investigated. Under aqueous conditions, phosphonic acids bind to TiO2 and not to SiO2 surfaces. A micropatterned support was prepared by electron beam microlithography and selectivity, of the surface modification was evidenced using scanning Auger electron spectroscopy (SAES). The second support was a mesoporous SiO2−TiO2 mixed oxide (10 mol % Ti) epoxidation catalyst prepared by sol−gel processing. Selectivity was deduced from the decrease of the catalytic activity upon modification and from chemical analysis; bonding modes to the surface were investigated using solid-state 29Si and 31P MAS NMR. The possibility to introduce different organic groups by successive treatments with a phosphonic acid and a silylating agent was illustrated in the case of the mixed oxide.

https://doi.org/10.1021/cm035367s