Local structure analysis of Ti species stabilized in ion exchangeable layer solids by x-ray absorption spectroscopy

Nano-sized titanium dioxides are incorporated into the interlayer spaces of ion-exchangeable layered perovskites, H1-xCa2-xLaxNb3O10 (x=0.0 similar to 0.75), by replacing the interlayer protons with positively charged TiO2 nan o-sol particles or basic titanium glycolate complex (titanatrane). Powder X -ray diffraction analysis, UV-Vis absorption spectroscopy, thermogravimetri c analysis, and N-2 adsorption-desorption isotherm measurements show that q uantum sized TiO2 particles are stabilized inbetween perovskite lattices to form micropores (S-BET= 37 similar to 110 m(2)/g). X-ray absorption spectr oscopy at the Ti K-edge was used for investigating the local environment ar ound Ti atoms constituting the interlayer pillars. According to the XANES s pectra, the 'as-pillared' Ti species have the same local environments with those of precursory species, which subsequently converted into TiO2 cluster s with rutile and anatase-like local structures when TiO2 nano-sol particle s and titanatrane are used as pillaring species, respectively. It is also f ound that the local environment of TiO2 remains almost constant irrespectiv e of the layer charge density, while the TiO2 pillar content and the microp orosity increase with the latter.