Structural role of zirconium in SiO2–ZrO2gels: evidence from17O NMR

Abstract
17 O MAS NMR has been applied to SiO2–ZrO2 mixed alkoxide derived gels. It demonstrates unambiguously that Zr–O–Si bonds are formed during gelling and that there is almost complete solid solution of Zr into the SiO2 network. Preliminary results on a ternary SiO2–TiO2–ZrO2 gel clearly indicate that Ti and Zr have different chemical behaviour in these systems.