X-ray absorption spectroscopy (XAS) study of the semicondutor-insulator interface in TiO2-based photocatalysts
1992; Elsevier BV; Volume: 56-58; Linguagem: Inglês
10.1016/0169-4332(92)90353-y
ISSN1873-5584
Autores Tópico(s)Glass properties and applications
ResumoThe geometrical structure around Ti ions in a system formed by amorphous titania coating on the silica surface has been studied using EXAFS and XANES. Samples were prepared by two methods: (I) impregnation from n-hexane solution of Ti-alcoxide, and (II) homogeneous deposition precipitation from water solutions. Analysis of the EXAPS data indicates that Ti ions are sixfold coordinated in both samples, the distance TiO being similar to that of the crystalline TiO2-anatase in samples prepared by method I, and slightly smaller in samples prepared by method II. Analysis of the higher shells in the EXAPS spectrum shows that although titania forms small aggregates in both cases, particles have grown in three dimensions, further than the monolayer.
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