Super-microporous TiO2 synthesized by using new designed chelating structure directing agents

Abstract

Amphiphilic chelating structure directing agents (SDAs) dodecyl-2-pyridinyl-methylamine (L-12) and hexadecyl-2-pyridinyl-methylamine (L-16) were prepared through condensation between pyridine-2-carboxaldehyde and C-12 or C-16 long chain primary amines followed by reduction of the corresponding imines with NaBH4. These tailor made SDAs were used to synthesize novel super-microporous titania materials, TiO2-L-12 and TiO2-L-16 under mild hydrothermal conditions. Powder X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscope attached with energy dispersive X-ray spectroscopy (SEM-EDS), CHN chemical analysis, N-2-sorption, H-1 and C-13 NMR, high resolution mass spectroscopy (HR MS), Fourier transformed infrared (FT IR), UV-visible absorption and emission spectroscopic tools were employed to characterize the SDAs and the super-microporous TiO2 materials. XRD and TEM image analysis suggested the nanostructure with wormhole-like disordered arrangement of super-micropores of ca. 1.4-1.68 nm width in these samples. The as-synthesized titania composites showed deep blue emissions at room temperature. On removal of the surfactants these materials showed very high surface areas (604-634 m(2) g(-1)) and good micropore volumes (0.26-0.29 cc g(-1)). (C) 2007 Elsevier Inc. All rights reserved.