Understanding the Zr and Si interdispersion in Zr1−xSixO2 mesoporous thin films by using FTIR and XANES spectroscopy

LEANDRO ANDRINI; PAULA C. ANGELOMÉ; GALO J. A. A. SOLER-ILLIA; FÉLIX G. REQUEJO

DALTON TRANSACTIONS

ROYAL SOC CHEMISTRY

Lugar: CAMBRIDGE; Año: 2016 vol. 45 p. 9977 - 9987

1477-9226

Zr?Si mixed mesoporous oxides were obtained in a wide range ofproportions, from 0 to 30% and from 70 to 100% of Si, using Si(OEt)4and ZrCl4 asprecursors and Pluronic F127 as a template. The oxide mesostructurewas characterized by transmission electron microscopy and 2D-smallangle X-ray scattering. Fourier transform infrared spectroscopymeasurements suggested a local homogeneous interdispersion of bothcations. Further selective studies using X-ray Absorption Near EdgeStructure (XANES) spectroscopy for separately Zr and Si localenvironments, allowed for demonstrating that the Zr coordinationvaries from close to 7 to 6, when its concentration in the mixedoxide is reduced. In addition, it was possible to determine that inmixed oxides with low Zr concentrations, Zr can fit into the spacesoccupied by Si in SiO2pure oxide. An equivalent XANES result was obtained for Si, which isalso compatible with the information obtained by FTIR. Furthermore,the Zr?O distance varied from close to 2.2 Å to 1.7 Å when the Zrconcentration decreased. Finally, our study also demonstrates theusefulness of XANES to selectively assess the local structure(coordination, symmetry and chemical state) of specific atoms innanostructured systems.