Preparation and characterization of mesoporous zirconium oxide. Part 2.

Mesoporous zirconium oxides were prepared by the sol-gel procedure under ba sic catalysis and in the presence of a series of surfactants: CnH2n+1N(CH3) (3)Br, with n = 8-18. Zirconium propoxide was used as a precursor. Basic co nditions were created by NaOH (pH > 11) or ammonia (pH = 10). The influence of the preparation parameters was examined by modifying several parameters such as Zr:H2O and Zr:surfactant molar ratios. The sol-step and then the p olymerization step were achieved at different temperatures. Drying of the s amples was carried out by lyophilization, or in vacuum oven at 383 K for 48 h. Calcination of the materials was made on the basis of TG-DTA results. T he oxides were characterized by adsorption-desorption isotherms of N-2 at 7 7 K, XRD, SAXS, solid-state C-13 CP/MAS NMR, FTIR, and SEM. (C) 2001 Elsevi er Science B.V. All rights reserved.