Structural, optical, photoluminescence and photocatalytic characteristics of sol-gel derived CeO₂-TiO₂ films

Abstract

CeO₂-TiO₂ films with different Ce/Ti mole ratios have been obtained using a simple sol-gel process. The films (1:0.25 and 1:0.5) containing more than 50% CeO₂ content show nanocrystalline characteristics. X-ray photoelectron spectroscopic study shows the variation of Ce⁴⁺/Ce³⁺ ratio with increasing TiO₂ content. Films with greater CeO₂ content exhibit higher porosity. The observed photoluminescence in the films is attributed to various defects resulting from crystallization and also to the relative amount of Ce³⁺ in the mixed oxide matrix. The transparency in the films appears to be inversely related to their photoluminescence activity, since the 1:0.5 film, which exhibits the best photoluminescence response, is incidentally also the least transparent film. The presence of photocatalytic activity in these films shows their potential use as an efficient photocatalyst.