Superacid ZrO2–SiO2–SnO2 Mixed Oxide: Synthesis and Study
Superacid ternary ZrO2 SiO2 SnO2 oxide has been synthesized by the sol-gel method with a different atomic ratio Zr:Si:Sn. The highest strength of acid sites has been observed in the ranges of 20 ≤ Zr4+ ≤ 29, 60 ≤ Si4+ ≤ 67, 11 ≤ Sn4+ ≤ 20 at.%. According to the XPS spectra and 119Sn, 29Si MAS NMR spectra of ZrO2 SiO2 SnO2 a partial shift of electron density from zirconium to silicon ions was observed resulting in the formation of superacid Lewis sites.