Nonaqueous Route toward a Nanostructured Hybrid Titanate

The first nonaqueous sol−gel route toward novel functional hybrid lamellar titanates is reported, enabling structural and morphological control of the nanostructured materials. The synthesis occurs at 220 °C in triethyleneglycoldimethylether (triglyme), with TiCl 4 and an amine−BH 3 complex (amine = t BuH 2 N, pyridine, Me 2 HN, Me 3 N) as precursors. Results from elemental and energy dispersive X-ray analyses, X-ray and electron diffractions, and Raman spectroscopy suggest a distorted pseudolepidocrocite-type structure for the hybrid titanate (N(CH 3 ) 4 ) 0.8 Ti 2 O 4 (OH) 0.8(1− x ) O 0.4· x (0 ≤ x ≤ 1), which intercalates tetramethylammonium cations. Structural control is performed with different amine complexes, yielding selectively anatase nanoparticles or titanate nanosheets. Addition of long chain amines leads to tunable titanate morphology and surface area, ranging from 90 to 220 m 2 ·g −1 . Analysis of the organic byproducts enables one to elucidate the reaction pathways toward titanium-oxo species, as well as in situ formation of the interlamellar ammonium species. The hybrid titanate undergoes structural evolution upon UV exposition, together with an increase of the photocatalytic activity, thus underlining the potential of nonaqueous sol−gel chemistry for investigating structural diversity of functional titanates.