Electronic and structural properties of ZrO2-SiO2 mesoporous films probed by XANES

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

Conferencia; 6th International Conference on Synchrotron Radiation in Materials Science; 2008

The mesoporous oxide films supported on different substrates present varied applications. It is important to understand electronic and structural characteristics for tailoring their mechanical, physicochemical, magnetic and related properties. Taking advantage of X-ray absorption based techniques to probe structural and electronic characteristics in the local range order; we studied the local environment of Si and Zr by XANES (X-ray Absorption Near Edge Structure) in a set of six samples of ZrO2-SiO2 on different substrates and relative ZrO2 concentrations. Samples were synthesized to have a homogeneous mixed oxide film with novel and unique properties for diverse applications. Zr L3 XANES split quantitatively probes the Zr environment by effects of crystal field on Zr ions in samples with lower ZrO2 concentrations. Zirconium environment results higher distorted (with closer oxygen neighbours) for lower Zr concentrations ( 70 w/w %). Si K XANES results revealed that there is not formation of zircon phase. In addition, Zr ions in low concentration are forced to adapt lower coordination and shorter Zr-O bond length. The Si K XANES experiments probe the electronic nature of Si by the white line intensity: the higher the SiO2 concentration the lower density of electronic holes for Si in SiO2.