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ABSTRACT 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.
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Structural Analysis of Colloidal Titania‐Based Ribbons and Their Self‐Assembly upon Drying
Synchrotron‐based small‐ and wide‐angle X‐ray scattering is used to elucidate the structure of low‐dimensional lepidocrocite–titanate‐based nanofilaments. In the colloidal state, they consist of quantum‐confined 1D NFs, loosely associated into nanoribbons, one lepidocrocite sheet thick (about 4 Å), 30–40 Å wide (5–8 NFs), and more than 300 Å long. In the dry state, they reach a final state of extended sheets, stacked three to about twenty high, whose crystallinity increases with stack height, in parallel with a decrease in photocatalytic activity. These findings suggest a kinetic pathway for the self‐assembly of initially 1D titanate nanoribbons into 2D and ultimately 3D structures, providing context for a recent body of work on these low‐dimensional materials.
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- Award ID(s):
- 2211319
- PAR ID:
- 10708046
- Publisher / Repository:
- Weily
- Date Published:
- Journal Name:
- Small Structures
- Volume:
- 6
- Issue:
- 8
- ISSN:
- 2688-4062
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1002/sstr.202500017
