Preparation and characterisation of mesoporous zirconium oxide

Mesoporous zirconium oxides were obtained using the polymeric sol-gel proce dure. The synthesis was carried out in the presence of two series of surfac tants, namely, N(C-n)(4)Br and N(CH3)(3)CnBr, with n = 8-18, and C-n, the l inear alkyl chain. Hydrolysis of zirconium isopropoxide was carried out bot h under acid and base catalysis, and also using acetylacetone (acac) as a s tabiliser. In order to obtain information on the sol-gel procedure in the a bove conditions, the composition parameters: Zr/H2O and Zr/surfactant ratio s were modified in a rather wide interval. Mesoporous textures were obtaine d, with surface areas and pore size distributions depending on the synthesi s conditions. The evolution of the sol-gel process and the resulting oxides were characterised with several tools: nitrogen adsorption-desorption isot herms, TG-DTA, XRD. SAXS, FTIR, C-13-CP/MAS NMR, and XPS measurements. The results showed that the phase structure of ZrO2 is sensitive to the composi tion parameters, and confirmed that in the presence of surfactants, the syn thesis occurred via a scaffolding mechanism. (C) 2001 Elsevier Science B.V. All rights reserved.