Study of rehydration process of alumina containing cerium doped silica gels by ultraviolet, visible and FTIR spectroscopy

Alumina containing Ce doped silica xerogel and glasses were prepared by sol‐gel processing at 500–1000°C under oxygen atmosphere. The partially densified gels were kept at 80% relative humidity for ageing and spectroscopic properties of the rehydrated partially densified gels were mainly studied by absorption and FTIR spectroscopy. With ageing time the generation of absorption bands of Ce³⁺ ions suggested the change of local symmetry of the Ce ions. Finally, fourfold splitting was observed for Ce³⁺ after 60 days indicating eight co‐ordinated water complexes like dodecahedral complexes having symmetry group D_2d.