High-Field 17O MAS NMR Investigation of Phosphonic Acid Monolayers on Titania

Gilles Guerrero (1) , Florence Brodard-Séverac (1) , Pierre Florian (2) , Christel Gervais (3) , Maquet Jocelyne (3) , P. Hubert Mutin (1)

1 ICGM ICMMM - Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier
2 CRMHT - Centre de recherches sur les matériaux à haute température
3 LCMCP (site Paris VI) - Laboratoire de Chimie de la Matière Condensée de Paris (site Paris VI)

High-field 17O MAS NMR was used to investigate the binding of self-assembled monolayers of 17O-enriched phosphonic acids deposited on a titania anatase support. The spectra were recorded at two different magnetic fields (9.4 and 17.6 T), to improve the reliability of the simulations of the different resonances. The spectra recorded at 17.6 T offer an excellent resolution between the different oxygen sites, PO, P−O−H, and P−O−Ti, thus greatly facilitating their quantification. The data reported here give direct evidence of the extensive formation of Ti−O−P bonds in the surface modification of titania by phosphonic acids. The presence of residual PO and P−O−H sites indicates the presence of several different binding modes in phosphonic acid monolayers. The chemical shift of P−O−Ti sites is consistent with bridging (as opposed to chelating) modes.

Domaines: Matériaux

Gilles Guerrero, Florence Brodard-Séverac, Pierre Florian, Christel Gervais, Maquet Jocelyne, et al.. High-Field 17O MAS NMR Investigation of Phosphonic Acid Monolayers on Titania. Chemistry of Materials, 2008, 20 (16), pp.5191-5196. ⟨10.1021/cm8012683⟩. ⟨hal-00327434⟩