室温合成および量子閉じ込め一次元レピドクロサイトチタン酸ナノフィラメントの長さ調整可能性

Herein we report on the facile, one-pot, scalable, room-temperature (RT) synthesis of quantum-confined, 1D lepidocrocite (1DL) titanate nanofilaments (NFs)-by reacting titanium oxysulfate with tetramethylammonium hydroxide, both cheap and ubiquitous precursors-for times that are significantly shorter than previously reported synthesis methods that required 80°C and, in some cases, days of reaction time. Samples are characterized by X-ray diffraction, Raman and X-ray photoelectron spectroscopies, small angle X-ray scattering, SAXS, scanning and transmission electron microscopy, revealing no significant differences from the higher-temperature synthesis methods, except in the fact that the lengths of the NFs varied. A parallelepiped model, one lepidocrocite layer thick, is used to fit the SAXS patterns of colloidal suspensions, CSs. The ribbons made from material reacted for 4 h are ≈33 nm long and 2.7 nm wide; after 12 h reaction time their lengths are >100 nm and their widths are ≈3.0 nm. This is the first diffraction-based evidence that the ribbons actually lengthen with time. Powders made using this method can be dried and re-dispersed in water. The resulting CS adsorbed more rhodamine 6G than any previous 1DL-based CS tested. From Tauc plots, we obtain bandgap energies of ≈4.0 eV, which is only weakly dependent on reaction time. This work establishes a simple, one-pot, RT, atmospheric-pressure, inexpensive and highly scalable method to synthesize quantum-confined titanate-based nanomaterials optimized for photocatalytic, environmental, and optoelectronic applications among others.