One-dimensional lepidocrocite composition

Abstract

Presented is a bottom-up approach to convert binary and ternary titanium carbides, nitrides, borides, phosphides, aluminides, and silicides into lepidocrocite nanofilaments that in some cases self-assemble into two-dimensional flakes by immersion in a quaternary ammonium solution at moderate temperatures. The resulting flakes are C-containing layers whose cross sections are composed of nanofilaments, some of which may be several microns long.

Description

[Technical Field]

[0001] REFERENCE TO RELATED APPLICATIONS This application claims priority to and the benefit of U.S. Patent Application No. 63 / 398,782, filed August 17, 2022, and U.S. Patent Application No. 63 / 373,490, filed August 25, 2022. All of the foregoing applications are incorporated herein by reference in their entirety for all purposes.

[0002] The present disclosure relates to the field of one-dimensional and two-dimensional materials, and to the field of metal oxide-based nanomaterials. [Background technology]

[0003] Nanostructured (NS) titanium dioxide (TiO2) has been and continues to be an important research subject due to its unique physical and chemical properties and potential applications in a wide range of fields, including paint pigments, catalysts, photocatalysts, photoluminescence, gas sensors, solar cells, and fuels. 1-11 The most important difference is that they have a much larger surface area. In terms of properties, low-dimensional solids allow for quantum confinement, which can create more active catalytic sites. Therefore, there is a long-standing need for one-dimensional materials with useful properties. Summary of the Invention

[0004] A bottom-up, sol-gel-based, one-pot, inexpensive, and scalable process can be used to fabricate TiO-based 1D nanofilaments (NFs). 12 Our method involves simply immersing earth-abundant, nontoxic, water-insoluble binary and ternary titanium carbides, nitrides, and borides in aqueous tetramethylammonium hydroxide (TMAH) solutions at ambient pressure and temperatures ranging from 50 to 85 °C for several tens of hours. This procedure converts the precursors into 1D NFs, which, after washing with water and filtration, self-assemble into quasi-2D flakes. 12We show that the structure of this 1D NF is lepidocrocite-based, henceforth referred to as 1DL. We also show that this NF grows along the a-direction or the 200-direction and stacks along both the b- and c-directions. [Brief explanation of the drawings]

[0005] In the drawings, which are not necessarily drawn to scale, like numerals may represent like components in different views. Like numerals with different letter suffixes may represent different instances of like components. The drawings illustrate generally, by way of example, and not by way of limitation, various aspects discussed herein. In the drawings: [Figure 1] Figure 1: a) XRD patterns of two samples cleaned with ethanol, one cleaned with ethanol and then with 0.5 M LiCl (see Methods section). The positions of the (200) and (002) peaks at (48°) and (62°) are crystallographic and are not processing invariant. All other peak positions are as follows. Note the logarithmic scale of the y-axis. The yellow bands are the outlines of three circular arcs / rings previously observed in SAD patterns of 2D flakes in TEM. 12b) Schematic of a DFT-generated structure with TiO ribbons stacked perpendicular to the b-axis. All predicted non-basal planes are also traced. The rectangle in the lower right indicates a unit cell with lattice constants a and b. Note that a is crystallographic, while b is not and depends on the spacing between the ribbons, taken here as 7.5 Å. The spacing between two adjacent Ti atoms along c, i.e., d002, is (1.5°) and gives rise to the peak (62°) seen in the diffraction and SAD patterns. 12b) Also shown in b and c is the approximate "thickness" (measured from outermost O to outermost O) of a two-atom-thick Ti ribbon. [Figure 2]Figure 2: Raman spectra of six samples cleaned with different methods (see the Methods section). In all cases, the obtained spectra matched that of lepidocrocite. The inset shows the effect of laser power on the spectra. At high powers, the material transforms from lepidocrocite to anatase. Laser powers of 10, 50, and 100% correspond to 6, 29, and 52 mW cm-2, respectively. [Figure 3] Figure 3: ABF TEM micrograph of an individual 1DL NF bundle oriented along the fiber axis. The inset in the lower left shows the FFT of the area boxed in blue. The red circle shows the predicted indices superimposed on the FFT after assuming a layer spacing of 7.5 Å along b. The inset in the lower right shows a schematic (not to scale) of lepidocrocite layers stacked along the b axis. The growth direction is along

[0200] , coinciding with the bundle axis. The inset in the upper left shows the software-generated SAD pattern assuming a 7.5 Å distance between ribbons along b. The inset in the upper right shows the HAADF image of the illustrated area. The precursor was TiB2, reacted in TMAH at 80 °C for 5 days. [Figure 4] Figure 4: Low-angle annular dark-field TEM micrograph of the same sample as in Figure 3. The area circled in red reveals a zigzag arrangement of Ti atoms in the nanoribbon, revealing a two-layer structure. [Figure 5] Figure 5: ABF TEM micrographs of the same sample as in Figure 3. The top image is an FFT generated from the blue square, showing a diffuse ring with no distinct diffraction spots. The bottom image is an FFT generated from the green square, showing a distinct diffraction spot, indicating that this region is mostly crystalline. [Figure 6] Figure 6: LAADF TEM image of loose NF bundles derived from TiC. b) Magnification of the dashed area in a shows the crystalline contrast of the NFs. Regions of well-ordered NFs show atomic column contrast consistent with lepidocrocite oriented along

[0100] . [Figure 7] Figure 7: Tauc plots as a function of washout (see Methods). [Figure 8]Figure 8: Scalable synthesis of nanofilament-based mesoporous particles. (a) Schematic of the temperature-controlled shaking incubator used to convert TiB2 precursor powder into nanofilament-based mesoporous particles. (b) Washing protocol to remove unreacted TMAH salt. (c) Lepidocrocite structure generated by DFT. Ribbons of Ti atoms two inches thick grow along the

[0100] direction and stack along the

[0010] direction (crystallographic a- and b-directions, respectively). (d) Various cations (both monovalent and divalent) intercalated in the interfilamentary galleries. [Figure 9] Figure 9: (a) XRD patterns (logarithmic scale) of the TiB precursor powder (top black curve) and a sample reacted for 1–5 days and then washed with ethanol before drying overnight at 50 °C in air. (The peaks at 26°, 48°, and 62° 2θ correspond to the 110, 200, and 002 planes of lepidocrocite, respectively. These values ​​correspond to the three arcs / rings observed in the SAD pattern of a 1-D TEM image. The 0k peak is indicated by an asterisk. The dashed black lines indicate the diffraction peaks of TiB. (b)–(d) SEM micrographs (various magnifications) of mesoporous particles after 5 days of reaction. The inset in (b) shows the MPPs size distribution obtained from the micrograph using ImageJ. Figures 15–17 show additional SEM images. [Figure 10] Figure 10: (a) STEM imaging of mesoscopic particles from a TiB2-derived sample shaken in TMAH at 80 °C for 5 days, washed with ethanol, and then dehydrated overnight at 50 °C in air. (b) and (c) LAADF STEM micrographs (various magnifications) of bundles of 1DL nanofilaments oriented along the fiber axis. The inset in (b) shows the FFT generated from the area enclosed by the yellow box. (d)–(h) EDX elemental maps of the mesoscopic particles shown in the inset in (a). [Figure 11] Figure 11: Mesoporous particle characteristics, (a)-(c) XRD patterns, (d)-(k) SEM micrographs. TiB2 precursor powder in TMAH solution was shaken at 80 °C for 5 days, washed with the solvents / solutions labeled on the panel, and then dried at 50 °C in air. [Figure 12] Figure 12: (a) Zeta potential (left Y-axis) and average hydrodynamic size (right Y-axis) of TiB2-derived samples shaken in TMAH at 80 °C for 5 days. [Figure 13] Figure 13: SEM micrographs (at various magnifications) of samples reacted for (a, b, c) 1 day and (d, e, f) 5 days. The samples were reacted in TMAH at 80°C, washed with ethanol, and then dried in air at 50°C. Micrographs after 2, 3, and 4 days of reaction are shown in Figure 25 and are identical to those shown here. [Figure 14] Figure 14: Reaction location and morphology. a) NFs are formed at the solid-liquid interface by the formation of TiO6 octahedra and their attachment to the bottom of the growing NFs. [Figure 15] Figure 15: SEM micrographs (various magnifications) of samples washed with ethanol and then dried overnight in air at 50 °C. All samples were reacted in a shaker at 80 °C for 5 days. [Figure 16] Figure 16: SEM micrographs (various magnifications) of samples washed with ethanol, 0.5 M aqueous LiCl, and water, then dried overnight in air at 50 °C. All samples were reacted in a shaker at 80 °C for 5 days. [Figure 17] Figure 17: SEM micrographs at varying magnifications of samples washed with ethanol, then immersed in 5M NaCl aqueous solution and water, and dried in air overnight at 50 °C. All samples were reacted in a shaker at 80 °C for 5 days. [Figure 18] Figure 18: HAADF imaging and EELS elemental mapping of MPP obtained after ethanol washing. (a) HAADF imaging of the NF bundle from which the EELS map was obtained. (b) HAADF image obtained simultaneously with the elemental mapping. No observable changes in morphology were observed in subsequent scans. (c) Elemental composition collected from the area enclosed by the dashed box in (b) and calculated using the Hartree-Slater model. (d)-(g) EELS elemental maps of Ti, O, C, and N, respectively. [Figure 19]Figure 19(a) XRD patterns of the sample before and after ion exchange with the salt solutions labeled in panel (b). (b)-(c) are the same as (a), except that after ethanol washing, the powder was further treated with LiCl solution and stirred in the salt solutions labeled in panel (b). The blue dashed line at 9.5 Å indicates the d-spacing of the sample washed with LiCl solution. The vertical black dashed lines / gray bands indicate the minimum and maximum d-spacings of the 110 non-basal reflections for various intercalants between the NFs. The vertical red dashed lines / bands indicate the 200 and 002 lepidocrocite reflections with 2θ values ​​of ~48° and 62°, respectively. The asterisk indicates the peak of unreacted TiB2, which was used as an internal standard to align the XRD patterns. [Figure 20] Figure 20: Characterization of mesoporous particles ((a) XRD pattern and (b) SEM micrograph). TiB2 precursor powder in TMAH solution was shaken at 80 °C for 5 days, washed with ethanol until neutral, and then stirred directly in the solutions labeled on the panel and dried at 50 °C in air. Note the logarithmic scale on the y-axis. [Figure 21] Figure 21: (a) and (b) Still images of ethanol-washed powder dispersed in ethanol and water, respectively. (c) Same as (a) but for powder treated with aqueous LiCl and then dispersed in water. [Figure 22] Figure 22: (a) and (b) AFM scans of colloidal suspensions (obtained by heating TiC in TMAH at 80 °C for 3 days, washing with ethanol until neutral, and then dispersing in water before and after 500-fold dilution and drop-casting onto a glass slide). The inset shows the height profile corresponding to the blue line in (d), with the thinnest filament measuring 1.5 nm in height. Figure reproduced with permission from Mat.Today, Elsevier (license number 5591960829133). [Figure 23]Figure 23: (a) Thermogravimetric plots of MPPs prepared by shaking TiB2 in TMAH solution at 80 °C for 5 d and then washing with ethanol until neutral. Some samples were further treated with LiCl or NaCl solution and then washed with water. All powders were dried in air at 50 °C. The vertical dashed lines indicate 200 °C and 400 °C. (b)–(c) XRD patterns of MPPs processed under the conditions labeled in the panels. All TGA powders were ramped to 800 °C at 10 °C / min in Ar. The black and blue asterisks in (b) and (c) indicate anatase and rutile, respectively, obtained after TGA. In (c), the vertical arrow on the middle green line indicates Li2Ti2O4, and the arrow on the lower red line indicates Na2Ti6O13 obtained after TGA. [Figure 24] Figure 24: (a)–(c) SEM micrographs of TiB2-derived mesoporous particles (washed with ethanol and dried in air at 50 °C) heated to 200 °C under Ar (shown as the red curve in Figure 23 b). (c)–(f) The same powders as (a)–(c) but heated to 800 °C (shown as the green curve in Figure 23 b). [Figure 25] Figure 25: SEM micrographs (at each magnification) of samples after reaction for (a, b, c) 2 days, (d, e, f) 3 days, and (g, h, i) 4 days. The samples were reacted in TMAH at 80°C, washed with ethanol, and then dried in air at 50°C. [Figure 26] Figure 26: SEM micrograph showing TiB2 particles transformed into 1DL NF by localized corrosion. The sample was reacted in TMAH at 80 °C for 3 d, washed with ethanol, and then dried in air at 50 °C. DETAILED DESCRIPTION OF THE INVENTION

[0006] The present disclosure can be more easily understood by referring to the following detailed description of the desired embodiments and the examples contained therein. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. In case of conflict, the present specification, including definitions, will prevail. Preferred methods and materials are described below, but methods and materials similar or equivalent to those described herein can be used in practice or testing. All publications, patent applications, patents, and other documents described herein are incorporated by reference in their entirety. The materials, methods, and examples disclosed herein are illustrative only and are not intended to be limiting.

[0007] The singular forms "a", "an" and "the" include plural referents unless the context clearly indicates otherwise.

[0008] As used in this specification and claims, the term "comprising" can include the embodiments "consisting of" and "consisting essentially of." As used herein, the terms "comprise(s)," "include(s)," "having(s)," "has(s)," "can(s)," "contain(s)," and variations thereof, are intended to be open-ended transitional phrases, terms, or words that require the presence of the named ingredients / steps and allow for the presence of other ingredients / steps. However, such descriptions should also be interpreted as describing compositions or steps as "consisting of" and "essentially consisting of" the listed ingredients / steps, which allows for the presence of only the named ingredients / steps, along with impurities that may result therefrom, and excludes other ingredients / steps.

[0009] As used herein, the terms "about" and "at" or "about" mean that the quantity or value in question may be approximately the same as another value designated. As used herein, unless otherwise indicated or inferred, it is generally understood to be a variation of ±10% of the nominal value. This term is intended to convey that similar values ​​promote the same results or effects as those described in the claims. That is, it is understood that amounts, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact, but can be approximated and / or larger or smaller as desired, reflecting tolerances, conversion factors, rounding, measurement errors, etc., and other factors known to those skilled in the art. In general, amounts, sizes, formulations, parameters, or other quantities or characteristics are "about" or "approximately," regardless of whether they are explicitly stated as such. When "about" is used before a quantitative value, it is understood that the parameter also includes the specific quantitative value itself, unless specifically stated otherwise.

[0010] Unless indicated to the contrary, numerical values ​​should be understood to include numerical values ​​that are the same when reduced to the same significant digits, and numerical values ​​that differ from the stated value by less than experimental error using conventional measuring techniques of the type described herein to determine the numerical value.

[0011] All ranges disclosed herein are inclusive of and independent of the recited endpoints (e.g., "between 2 grams and 10 grams, and all intermediate values, includes 2 grams, 10 grams, and all intermediate values"). The endpoints of the ranges and any values ​​disclosed herein are not limited to the exact ranges or values, but are sufficiently imprecise to include values ​​that approximate these ranges and / or values. All ranges are combinable.

[0012] As used herein, approximations can be applied to modify any quantitative expression that can vary without resulting in a change in the basic function to which it relates. Thus, values ​​modified by terms such as "about" or "substantially" may, in some cases, not be limited to the exact value specified. At least in some cases, approximations may correspond to the precision of the instrument used to measure the value. The modifier "about" should also be considered to disclose a range defined by the absolute values ​​of the two endpoints. For example, the phrase "from about 2 to about 4" also discloses the range "from 2 to 4." The term "about" can refer to plus or minus 10% of the indicated numerical value. For example, "about 10%" can indicate a range of 9% to 11%, and "about 1" can mean 0.9 to 1.1. Other meanings of "about" are apparent from the context, such as rounding, so "about 1" can also mean 0.5 to 1.4. Additionally, the term "comprising" should be understood to have the open-ended meaning of the term "including," but also includes the closed meaning of the term "consisting." For example, a composition consisting of components A and B can be a composition containing A, B, and other components, but can also be a composition consisting only of A and B. All documents cited herein are incorporated by reference in their entirety for all purposes.

[0013] Results and Discussion All experimental details are given in the Methods section.

[0014] Figure 1 plots the XRD patterns (logarithmic scale) of two samples synthesized by reacting TiB2 powder with TMAH at 80 °C for 5 days. After the reaction, the resulting powder was washed with ethanol until the pH reached 7. In one case, the powder was directly dehydrated from ethanol at 50 °C in air (bottom blue curve in Figure 1a). In the other case, the precipitate was further stirred in LiCl solution, washed with pure water, and then air-dried in air (top red curve in Figure 1a).

[0015] The vertical dashed lines in Figure 1 indicate two low-intensity unreacted TiB peaks used as an internal standard. When the powder was washed with ethanol, the XRD pattern was characterized by seven basal reflections with a d-spacing of (11.5 Å), which is attributed to the stacking of "2D" flakes consisting of an in-plane arrangement of 1D flakes (see below). Upon washing with LiCl (see the "Methods" section), the d-spacing value decreased to (9.5 Å), indicating that the TiB peaks were in the range of 1000 to 12000 Å. + The cation is Li + The yellow bands in Figure 1a represent non-basal reflections of lepidocrocite, with 2( values ​​of (26°, (48°, and (62°). These peak positions are in good agreement with our previous XRD patterns and rings previously observed in TEM SAD patterns. (12)。

[0016] Figure 2 shows the Raman spectra of six samples processed using the different methods outlined in the Methods section. 13 ) Looking back, the previous spectrum 12 It was revealed that the laser power used to obtain lepidocrocite was too high, resulting in the transformation of lepidocrocite to anatase, as evidenced by the change in the Raman spectrum from lepidocrocite to anatase upon increasing the laser power (inset 2).

[0017] The next challenge is to match the XRD pattern (Figure 1a) with the lepidocrocite structure, because, except for the (200) peak at (48°2) and possibly the peak at (62°2), all other peaks are not typical of lepidocrocite. 9、14 Lepidocrocite is typically characterized by a strong (103) peak at (26-28°) with a smaller (110) peak to its left. 9、14 More recently, Ma et al. 15 published an XRD pattern attributed to lepidocrocite, showing four peaks at (101), (004), and (200), and one peak near 62°2((), which was not assigned.

[0018] To model our structure, we used DFT calculations of lepidocrocite. 16 Lepidocrocite consists of thick ribbons of Ti atoms stacked along the b direction (Figure 1b). Half of the O atoms are four-fold coordinated, and the other half are two-fold coordinated. The (200) peak in the XRD pattern is due to the vertical plane labeled as such in Figure 1b. As discussed below, the plane responsible for the 62° peak is shown in Figure 1c and indexed as (002). In our coordinate system (Figure 1b), the (26° peak is assigned to the (110) plane (Figure 1b). Most of the other peaks are characteristic 2D 001 peaks. Note that the ethanol-washed sample (blue pattern in Figure 1a) exhibits higher stacking order than the LiCl-washed sample.

[0019] Figure 3 shows an annular bright-field (ABF) TEM image of a bundle of TiB2-derived NFs and the FFT of the central part of the micrograph enclosed in a blue box. The lepidocrocite structure generated by DFT to simulate the FFT. 16 Starting from the lattice plane, the c-axis was tilted to the zone axis (Fig. 1b). The lepidocrocite layers were stacked along the b-axis so that the growth direction was 0100, and importantly, coincided with the bundle axis (Fig. 1b) (bottom right inset 3). The stacking distance between the two-dimensional layers was adjusted to coincide with the (010) orientation.

[0020] The (020) spot was generated on the FFT. The other spots (top left inset) were generated by the single crystal diffraction module in the Crystal Maker software. Otherwise, only one adjustable parameter was used.

[0021] The agreement between the FFT spots and our simulated SAD (red circle in the lower left inset) is excellent, suggesting that the 110 and 200 d-spacings are 3.6 Å and 2.1 Å, respectively. The corresponding distances obtained from the XRD patterns of the (110) and (200) planes (hereafter referred to as d110 and d200, respectively) are 3.5 ± 0.8 Å and 1.89 ± 0.01 Å. 12 Such d-spacing discrepancies are not unexpected, especially when using atomic-resolution STEM FFT. The position of the "diffraction spot" in the FFT is based on the calibration of the underlying STEM image, which is affected by the calibration accuracy of the underlying image, scan distortion, and image pixel size. This may be due to the fact that DFT models 2D lepidocrocite, while our experiments deal with 1D. Also, our material is C, 12 However, the DFT model also shows that this fact is important for better understanding where the C atoms are located. Needless to say, the XRD results are more accurate, but the symmetry of the diffraction peaks matches. Based on the d200 value, the a lattice constant is 3.78 Å, which is consistent with the results of Tominaka et al., who prepared 2D lepidocrocite using TMAH. 17 This is slightly smaller than the reported value of 3.803 Å.

[0022] In the bright regions where Ti atomic columns are presumably stacked, a zigzag pattern of Ti atoms can be discerned, as shown in Figure 4, which is consistent with the schematic diagram in Figure 1b.

[0023] Using Scherr's method, the domain sizes along the

[0110] ,

[0200] , and

[0002] directions are estimated to be 4.2 nm, 7.3 nm, and 3.4 nm, respectively. These dimensions are small compared to the micrographs shown in Figures 3, 4, and 5, suggesting that order is formed at a finer scale than the relatively large macroscopic features such as two-dimensional flakes and fiber bundles observed.

[0024] It is also true that while the "crystalline" regions were key to deciphering the structure, a significant portion of the bundle (2D flake) is not crystallized. Figure 5 shows the regions enclosed by the blue and green squares. The FFT pattern of the blue region (top left inset of Figure 5) is clearly amorphous. The corresponding FFT of the green region (bottom inset) yields the same pattern as shown in Figure 3, but with significantly less sharpness.

[0025] At this stage, it is important to critically evaluate the proposed structure. Based on DFT calculations, the thickness of the 2-Ti atomic ribbon from the outermost O layer to the outermost O layer is (4.1 Å) (Figure 1b). Assuming a total interlayer distance of 7.5 Å, the intergallery distance is (3.4 Å). It is a mystery why the (0h0) peak, clearly visible in the FFT (Figure 3), is missing from the XRD pattern. The origin of all other non-basal peaks can be traced to the planes where Ti atoms in one ribbon (unit cell) are connected to ever-increasing Ti atoms in neighboring ribbons (numbered in Figure 1b), as shown in Figure 1b. In our coordinate system, the first of these tilted planes is (110), whose d-spacing coincides with the XRD peak at 26° (26°).

[0026] The d-spacing of the (62°2) peak does not coincide with any (1n0) plane (Figure 1b) and does not appear in the simulated FFT shown in the upper left inset of Figure 3. Therefore, it must be related to the c-axis. The DFT c-lattice parameter LP is 3.01 Å, and the (002) d-spacing d002 is 1.5,2° (62.2°). In the XRD pattern, this peak appears at 61.0 ± 0.4°. 12 , the c-LP corresponds to 3.04 ± 0.06 Å. There are two (002) reflections. The first is associated with stacking of NFs along the c-axis at 2 < 20° (Fig. 1a). The other is crystallographic and originates from X-rays reflecting off the top of the ribbon shown in Fig. 1c, representing 62° (2).

[0027] From these results, we have identified two of the three faces of the 1DL NF: (100) and (001). What about the third face, i.e., (010)? In this face, the Ti and O atoms are coplanar (Fig. 1c). If the surface were cut so that only two Ti layers remained, a zigzag pattern would form (Fig. 1c), which would be quite difficult to distinguish from the (001) surface, which also forms a zigzag pattern (Fig. 4). Regardless of this comment, from the TEM image shown in Fig. 3 and other data, we can tentatively conclude that the thickness of the (001) nanoribbon is on the order of 6. Its DFT width is 5.7 Å (Fig. 1c). If this width were larger, the relatively homogeneous microstructure shown in Fig. 3 would not have been possible. Importantly, if relatively large segments were present, they would have been crystalline and therefore easily identifiable by TEM.

[0028] MXene 18 In the literature on and other 2D materials, it is well known that finding multilayers (MLs) with an "edge-on" orientation is nontrivial, since most 2D flakes have basal planes parallel to the surface. 19 Generally, the flakes are facing upward and the basal surface is exposed edge-on at the edge of the MLs. 18 Here, the opposite is true: most regions are either poorly crystalline, amorphous, or exhibit "edge-on" formation (Figures 3, 4, and 5). When TEM imaging of 2D lepidocrocite, which has a strong (101) peak in X-ray diffraction, it is not difficult to find relatively large islands and lattice fringes. 15、17 Their absence here strongly suggests that they do not exist; instead, we have 1DL NFs that have self-assembled into "2D" flakes. This is important because if the NFs seen here were truly one-dimensional, they would have a cross-section of 5 × 6 Å. 2 We emphasize that we are not saying that 2D layers do not exist, as is evident from the XRD patterns. What we mean is that the "2D" flakes consist of 1DL NFs self-assembled into layers.

[0029] Figure 6 further supports the conclusion that we are dealing with NFs. Individual NFs are easily discernible in this TiC-derived sample. These comments aside, we acknowledge that what we see in the micrograph could, although unlikely, be the edge of a large sheet that has extended beyond the plane of the page.

[0030] At this stage, it is important to verify the above conclusion. Of the three distances, d200, d002, and d101, only the first two are crystallographically correct. Therefore, in all materials fabricated to date (more than 200 runs), the position of the 200 peak remains constant at 48°2 in the d(((() pattern (Figure 1a)). 12 and (62°2 peak 12 Similarly, the position of the (110) peak is a function of the surrounding medium (Fig. 1a) and cannot be crystallographic. Another important observation consistent with this idea is that the distance between the NFs along the red line plotted in Fig. 3 is (7 Å), which is comparable to the 7.5 Å used to theoretically fit the FFT patterns.

[0031] One is oriented along the (010) or b-axis (inset at the bottom right of the figure), and the other is oriented out of the plane of the page (along the c-axis), which is responsible for the low-angle reflection labeled (001) in Figure 1. STEM images do not provide much information about the c-axis spacing or stacking. Not surprisingly, this spacing is also a function of the nature of the cations surrounding the NFs.

[0032] This is shown in Figure 1 by the peak labeled (00l). Most of the peaks, and the most intense peaks, are (00l). This is especially noticeable when the Y-axis is plotted linearly rather than logarithmically.

[0033] Finally, although the cleaning protocol changes the spacing between the NFs, these changes do not affect the band gap. The Tauc plot (Figure 7) confirms the existence of the previously reported (4 eV) indirect band gap. 12 This band gap energy is a record for a TiO2-based material prepared by a bottom-up approach and is an independent confirmation of quantum confinement. There is a large literature on one-dimensional TiO2-based materials, but to our knowledge, none have reported a quantum size effect on the band gap.

[0034] In conclusion, 1D NFs produced by reacting TiB2 and TiC powders in TMAH for 805 days crystallize in the lepidocrocite-type TiO2 structure. The NFs grow in the <0100> direction and stack along the b-direction in the plane where the NFs self-assemble to form bundles (Figure 3), or form larger 2D flakes as shown in previous studies. 12 And while the "crystalline" regions are key to understanding the structure, it's also true that a significant portion of the bundles and 2D flakes are not crystallized. Some regions appear amorphous.

[0035] Regardless of the quality of the NF self-assembly, the cross section of the NF is 6x5Å. 2 Assuming a theoretical specific surface area of ​​>1700m 2 / g, which is an astonishing figure for titanium-containing materials and explains some of the remarkable properties these materials exhibit. Furthermore, precursor powders such as TiC, TiB2, and Ti-containing MAX phases are earth-abundant and non-toxic.

[0036] method Materials synthesis and processing Samples of 1DL NF were prepared by shaking TiB2 (Thermo Scientific, -325) powder with aqueous tetramethylammonium hydroxide (TMAH) (Alfa Aesar, 25 wt.% in deionized water, 99.9999%) at 80 °C for 5 days in a temperature-controlled incubator / shaker. In all cases, the Ti:TMAH molar ratio was maintained at 0.6. After the reaction, the resulting powder was washed with ethanol (Decon Lab Inc., 200 proof) until the pH reached 7. The powder was then dehydrated overnight at 50 °C in air. To investigate the potential effect of drying temperature, another sample from the same batch was dehydrated at room temperature.

[0037] To evaluate the ion exchange capacity, the ethanol-washed precipitate was immersed in one of the following salt solutions (while still wet) for 6 hours each, followed by stirring three times: 0.5M LiCl, 5M LiCl, 0.5M NaCl, or 5M NaCl, and then washed three times with pure water to remove unreacted salts and reaction products. All salts were purchased from Alfa Aesar with a purity of 99% or higher. The LiCl- and NaCl-washed powders were air-dried at 50°C as described above.

[0038] To compare samples treated with a shaker with samples prepared with magnetic stirring 20 In one case, TiB2 powder was magnetically stirred at 300 rpm in a TMAH solution according to the molar ratio, temperature, and conditions described above. After the reaction, the resulting slurry was washed six times with ethanol until the pH reached (7), redispersed, shaken for 5 minutes, and then centrifuged at 3500 rpm for 30 minutes. The resulting colloidal suspension was filtered using vacuum-assisted filtration to produce a filter membrane.

[0039] The Raman spectra shown in Figure 2 were obtained for six samples: ethanol washed, 0.5M LiCl, 5M LiCl, 0.5M NaCl, 5M NaCl, and magnetically stirred.

[0040] X-ray diffraction XRD patterns were acquired using a diffractometer (Rigaku MiniFlex) with Cu Kα radiation (40 kV, 15 mA) in the range of 2–65°2 with a step size of 0.02° and a dwell time of 1 s. All XRD patterns were obtained from powders dried overnight at 50°C in air.

[0041] Raman spectroscopy Two sets of Raman spectra were obtained in two different laboratories. At Drexel University, Raman spectra were collected in air at room temperature. Measurements were performed on a Renishaw InVia (Gloucestershire, UK) instrument in inverted reflectance mode equipped with a 63× (NA = 0.7) objective and a diffraction-based room-temperature CCD spectrometer. An Ar+ laser (514 nm) was used, and the laser power was kept in the range of ~0.5–1.5 mW.

[0042] For another set obtained in Fayetteville, a suspension of TiB2-derived QDNs at a concentration of 10 mg / mL was prepared in deionized water (Millipore), isopropyl alcohol (>99.7%, Sigma-Aldrich), and dimethyl sulfoxide (DMSO, 99.9%, Sigma-Aldrich) as solvents. The suspension was drop-cast onto a microscope slide and allowed to air-dry for 24 h at room temperature (RT). Raman spectra were collected at room temperature using an XploRA PLUS confocal Raman microscope (Horiba Scientific, Piscataway, NJ, USA) with a 250 mm focal length spectrometer in backscattering geometry. The spectrometer was first calibrated to obtain a 1 μm spot size using a silicon tip, excited with an air-cooled 532 nm solid-state laser (100 mW), and a 100x objective (NA = 0.9, WD = 0.21 mm). A 1200 gr / mm grating was used, and scattered light was collected by a 1024x256 pixel thermocouple (TE) air-cooled charge-coupled device (CCD) detector, with a 1cm -1 A spectral resolution of 1000 nm was obtained. The laser power was attenuated to 10%, 25%, 50%, and 100% using a neutral density (ND) filter wheel, and spectra were acquired at low power (10%) or higher. Raman spectra were obtained from 75 to 1200 cm.-1 The Raman spectra were collected in the range of 100 s with an integration time of 2 s and 64 accumulations. Using LabSpec 6 software, the collected Raman spectra were fitted according to the Gaussian-Lorentzian function to determine the peak positions and intensities.

[0043] transmission electron microscope Atomic-scale characterization was performed using an aberration-corrected cold-field emission TEM (JEOL ARM200CF) operating at a primary electron energy of 200 kV. 21 Imaging was performed with an emission current of 15 μA and an electron probe half-convergence angle of 24 mrad, resulting in an electron probe size of approximately 80 pm. Annular bright-field (ABF) imaging is a coherent imaging technique. 22-23 The low-angle annular dark field (LAADF) imaging was performed with an outer angle of 23 mrad and an inner angle of 11 mrad. The inner angle was 30 mrad and the outer angle was 120 mrad. 24 was collected at an inner detector angle of 68 mrad and an outer detector angle of 280 mrad. The main contrast mechanism in HAADF imaging is related to the square of the mean atomic number and the total thickness of the atomic column. 25

[0044] TEM samples were prepared by dispersing the nanofilament powder in 5 ml of methanol. This solution was drop-cast onto a 3 mm copper mesh coated with a lacey carbon film and allowed to dry for 1 h. The TEM grid was then mounted on a plasma-cleaned double-tilt holder and inserted into the microscope column.

[0045] References Kumar,S.G.;Devi,L.G.,Review on Modified TiO2 Photocatalysis under UV / Visible Light:Selected Results and Related Mechanisms on Interfacial Charge Carrier Transfer Dynamics.The Journal of Physical Chemistry A 2011,115(46),13211-13241. Schaub,R.;Thostrup,P.;Lopez,N.;Lagsgaard,E.;Stensgaard,I.;Norskov,J.K.;Besenbacher,F.,Oxygen vacancies as active sites for water dissociation on rutile TiO 2(110).Physical Review Letters 2001,87(26),266104. Wang,A.S.D.;Sasaki,T.,Titanium Oxide Nanosheets:Graphene Analogues with Versatile Functionalities.Chem.Rev.2014,114,9455?9486. Bourikas,K.;Kordulis,C.;Lycourghiotis,A.,Titanium Dioxide(Anatase and Rutile):Surface Chemistry,Liquid-Solid Interface Chemistry,and Scientific Synthesis of Supported Catalysts.Chemical Reviews 2014,114(19),9754-9823. Wang,X.;Li,Z.;Shi,J.;Yu,Y.,One-dimensional titanium dioxide nanomaterials:nanowires,nanorods,and nanobelts.Chemical reviews 2014,114(19),9346-9384. 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Esmat,M.;Farghali,A.A.;El-Dek,S.I.;Khedr,M.H.;Yamauchi,Y.;Bando,Y.;Fukata,N.;Ide,Y.,Conversion of a 2D Lepidocrocite-Type Layered Titanate into Its 1D Nanowire Form with Enhancement of Cation Exchange and Photocatalytic Performance.Inorganic Chemistry 2019,58(12),7989-7996. Ma,J.;Reeves,K.G.;Porras Gutierrez,A.-G.;Body,M.;Legein,C.;Kakinuma,K.;Borkiewicz,O.J.;Chapman,K.W.;Groult,H.;Salanne,M.;Dambournet,D.,Layered Lepidocrocite Type Structure Isolated by Revisiting the Sol-Gel Chemistry of Anatase TiO2:A New Anode Material for Batteries.Chemistry of Materials 2017,29(19),8313-8324. Reeves,K.G.;Ma,J.;Fukunishi,M.;Salanne,M.;Komaba,S.;Dambournet,D.,Insights into Li+,Na+,and K+Intercalation in Lepidocrocite-Type Layered TiO2 Structures.ACS Applied Energy Materials 2018,1(5),2078-2086. Tominaka,S.;Yamada,H.;Hiroi,S.;Kawaguchi,S.I.;Ohara,K.,Lepidocrocite-type titanate formation from isostructural prestructures under hydrothermal reactions:observation by synchrotron X-ray total scattering analyses.ACS omega 2018,3(8),8874-8881. Naguib,M.;Kurtoglu,M.;Presser,V.;Lu,J.;Niu,J.;Heon,M.;Hultman,L.;Gogotsi,Y.;Barsoum,M.W.,Two Dimensional Nanocrystals Produced by Exfoliation of Ti3AlC2.Advan.Mater.2011,23,4248-4253. 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[0046] Titania (TiO2) nanostructures have been and continue to be an important research subject due to their unique physical and chemical properties and potential applications in a wide range of fields, including paint pigments, catalysis, photocatalysis, photoluminescence, gas sensors, solar cells, and fuel cells. Among commercially available nanostructured titanias is Evonik's Aeroxide TiO2P25 (formerly sold by Degussa), hereafter referred to as P25. P25 is synthesized by flame pyrolysis of TiCl4 and is attractive for its high photocatalytic activity.

[0047] In many respects, P25 was, and is still considered, the gold standard for TiO2-based catalytic and photocatalytic applications. Flame pyrolysis is a relatively expensive process, and if P25 were less expensive, it would likely find many more applications. We have therefore developed a significantly cheaper process for producing one-dimensional (1D) titania and shown that it outperforms P25 in many applications.

[0048] This recipe involves reacting precursor powders with aqueous tetramethylammonium hydroxide (TMAH) solution (contained in a polyethylene bottle) at temperatures ranging from 50°C to 85°C for several days. In one case, five Mn-containing powders, including Mn3O4, Mn2O3, and MnB, were converted into birnessite-based two-dimensional (2D) sheets with a thickness of 2±0.4 nm and a width of 200 nm by reacting them in aqueous TMAH solution for several days. These 2D birnessite sheets were highly crystalline and exhibited improved electrochemical reactivity for both reversible O2 electrocatalysis and supercapacitor applications.

[0049] Following the same protocol, immersion of FeB powder in aqueous alkaline solutions (TMAH; tetramethylammonium hydroxide (TBAH); or potassium hydroxide (KOH)) produced ferromagnetic Fe3O4 nanoparticles with an average particle size of ~15 nm.

[0050] In another example, inexpensive, earth-abundant, water-insoluble Ti-containing precursors, including TiC, TiN, and TiB2, were converted into 1D nanofilaments (NFs). In this recipe, Ti-containing precursor powders and aqueous TMAH solution were reacted in a polyethylene bottle at temperatures ranging from 50 to 85 °C for several days. We concluded that the 1D NFs crystallized in a lepidocrocite-type TiO2-based structure (Figure 8c). Hereafter, we refer to these lepidocrocite-type 1D NFs as 1DLs. The cross section of our 1DL NFs is (5x7Å). 2 This extreme size leads to a bandgap energy E gIt was concluded that the 4 eV recorded was due to quantum size effects.

[0051] We have concluded several studies showing that our 1DL has unique and superior performance to P25. The photochemical hydrogen production rate when exposed to the equivalent of one sun's light was approximately one order of magnitude higher than P25 tested under the same conditions. In the field of water purification, our 1DL achieved a record high uranium (U 4+ Finally, we demonstrate that 1DL, which contains a healable and dynamic covalent thiophosphorus network, can be composited to a filler load of 60 wt% and exhibit a 500-fold increase in modulus compared to the bare polymer.

[0052] After the reaction, the mixture was washed with ethanol (EtOH) (to pH 7) and then with water, resulting in the formation of quasi-two-dimensional (p-2D) structures upon filtration. We call it "quasi-two-dimensional" because the flakes composed of 1DL NFs are only 2D in appearance. We have shown that these p-2D flakes exist in the colloid even after short reaction times. This suggests that water exerts a strong driving force to align 1DL NFs perpendicular to their <0200> growth direction. This self-alignment first leads to the formation of nanobundles and μ-fibers, which then self-align into p-2D flakes. Regardless of the experimental conditions and final morphology, 1DL NFs remain the essential building blocks.

[0053] Here, we show that drying 1DL NFs in ethanol (i.e., without dispersing them in water) leads to the formation of spherical hollow particles (hereafter MPPs), whose diameter is approximately equivalent to that of the precursor powder. In this work, we: i) report the large-scale synthesis (100 g batch) of MPPs composed of 1DL NFs; ii) elucidate the mechanism leading to the formation of MPPs; and iii) show that, similar to other titanate layered compounds, the inter-NF spaces offer excellent ion exchange properties. To that end, we investigated the TMA present after the reaction step. + Cation to H + , Li+ , Na + , Mg 2+ , Mn 2+ , Fe 2+ , Ni 2+ , Co 2+ , or Zn 2+ It can be easily replaced by cations (see schematic in Figure 8d). iv) TMA + or Li + The surface charge and dynamic radius of ion-intercalated MPPs are measured.

[0054] TiB2 was chosen as the starting precursor because it is the most reactive compared to TiC and TiN. Large batches of TiB2 powder can be converted almost completely to 1DL at 80 °C in 3 days.

[0055] Results and Discussion The precursor was reacted with TMAH using a hotplate and magnetic stirrer. A temperature-controlled shaking incubator was used to prepare large batches of 100 g at a time. See the Experimental Procedures section for experimental details. Briefly, 100 g of commercially available TiB2 powder was shaken with ~1 L of 25 wt.% TMAH aqueous solution at 80 °C for 1–5 days in a temperature-controlled shaking incubator (Figure 8a). In one set of experiments, the resulting powder was washed multiple times with EtOH using an overhead mixer until the pH reached 7 (Figure 8b).

[0056] Preliminary results showed that MPP did not maintain its morphology when the EtOH-washed sample was placed in water. + The cation is Li + The morphology of the MPPs was maintained when the EtOH-washed powder was replaced with 0.5 M LiCl, 5 M LiCl, 0.5 M NaCl, or 5 M NaCl (Fig. 9d). The powders were then rinsed several times with pure water to remove residual salts and then dried at 50 °C in air.

[0057] To evaluate the ability to intercalate various monovalent and divalent cations between the NFs, both the EtOH- and EtOH / LiCl-washed powders were further treated with one of the following aqueous solutions (Figure 8d): i) 0.1 M nitric acid, HNO, or 0.5 M acetic acid; or ii) a 0.02 M aqueous solution of one of the following salts: MgCl, MnCl, FeSO, CoCl, NiCl, or ZnCl. In both cases, after immersion in the salt solution, the powders were washed several times with pure water and dried in air at 50 °C for 24 h.

[0058] Characterization of 1DL NF Before proceeding, we can review the X-ray diffraction (XRD) signature of the 1DL NFs. The reaction time dependence of the XRD pattern (logarithmic scale) is shown in Figure 9a. In a typical 1DL XRD pattern (Figure 9a), three peaks are present. The first is due to the unreacted precursor—TiB2 in this case—and is indicated by the dashed black line in Figure 9a. These are useful in that they can be used as an internal standard. The second 010 peak at the lower 2q angle and its higher 0k0 reflection, indicated by an asterisk, reflect the value of the d-spacing between the NFs stacked along the b direction. As with other 2D materials, the position of these peaks is a strong function of which cations are intercalated. The key point here is that the distance is between the NFs, not between the flakes. Based on the results shown in Figure 9a, it is clear that after the first day, the d-spacing is no longer a function of reaction time.

[0059] The (110) peak, located near 2q of ~26° (shown as the gray band in Figure 9a), is a weak function of cations between the NFs. The final and most fundamental peaks, located at 2q values ​​of ~48° and 62°, are shown as the red band in Figure 9a and are indexed as 200 and 002, respectively, in the lepidocrocite structure. These peaks are crystallographically useful and, as confirmed herein, should be completely independent of the cations in the system. From these 2q values, the a- and c-lattice parameters of lepidocrocite, namely, 3.7 Å and 2.9 Å, are obtained.

[0060] As mentioned previously, Figure 9a shows the XRD pattern of the TiB2 precursor powder (top pattern in Figure 9a) and the time dependence of the XRD patterns of those reacted at 80 °C from 1d to 5d (top to bottom). As the reaction time increased from 1d to 3d, the intensity of the TiB2 diffraction peak gradually decreased, and the 1DL diffraction peak became dominant. The latter is again recognized by the two red bands in Figure 9a and the low-angle 010 peak at 9°2q (and its higher-order peaks). From the latter, the distance between the 1DL NFs was calculated to be 11.5 Å. These results suggest that the conversion of the precursor to 1DL powder was complete after 3 days. However, to minimize the proportion of unreacted precursor, the reaction was carried out for 5 days. All characterization was performed on the powder reacted for 5 days (blue curve in Figure 9a).

[0061] Scanning electron microscope (SEM) micrographs of typical MPPs after washing with EtOH to pH 7 are shown in Figures 9b–d. At the millimeter scale, the powder was well dispersed, with little or no aggregation observed (Figure 9b). At higher magnification, the MPPs were porous, mostly spherical, with an average size of ~13 μm (Figure 9b inset), and composed of entangled 1DL NF bundles (Figures 9c and 9d). The shape and size of the MPPs were remarkably consistent across the 50 different batches prepared and characterized to date. Additional micrographs are shown in Figures 15–17. To summarize this section: After washing with EtOH, the 1DL NFs self-assemble into non-aggregated, free-flowing MPPs with particle sizes ranging from 5 to 30 μm (Figure 2b and inset).

[0062] To better understand the structure of the MPPs, we imaged them with HR-STEM (Figures 10a–c). Assuming the fiber bundle shown in Figure 10a represents a single MPP, its diameter is approximately 1 μm. At higher magnification, it is clear that this bundle is composed of numerous 1DL NFs (Figures 10b and c). A low-angle annular dark-field (LAADF) image (Figure 10c) reveals that the building blocks remain NFs, each 2 Ti atoms wide, with a zigzag pattern. The fast Fourier transform (FFT) pattern of the bundle (inset in Figure 10b) yields two major circular arcs, confirming the one-dimensional nature of our NFs. The arcs also bisect the

[0100] growth direction.

[0063] Turning to the composition of the 1DL bundles, the STEM-EDS map of the MPP shown in the inset of Figure 10a was obtained. This is consistent with the near-complete conversion of TiB2 to 1DL NFs and the effectiveness of this process in cleaning the B-containing reaction products. From a scaling perspective, these powders were not centrifuged or filtered. Note the uniform distribution of Ti and O atoms (Figure 10e-f). The calculated atomic percentages of Ti and O are 24.5% and 49.5%, respectively, consistent with the TiO2 stoichiometry. The lacy carbon support can be seen in the C map (Figure 10g), which is shadowed by C in the 1DL. The uniform distribution of N on the MPP is also evident in the TMA map. + This confirms that ions are intercalated between the NFs (Figure 10h). The large overlap between the K-edge of N and the L-edge of Ti makes it difficult to quantify the amount of N present.

[0064] To resolve this issue and obtain a more accurate understanding of the carbon content, electron energy loss spectroscopy (EELS) spectra were acquired, in which the Ti and N peaks were easily distinguishable, and the elemental composition was calculated using the Hartree-Slater cross-section model. To further reduce the contribution of surface hydrocarbons, the sample was cooled in situ using a liquid nitrogen N2 cold stage. The elemental map (Figure 18) obtained from the core loss spectrum shows concentrations of Ti and O consistent with TiO2 stoichiometry. The carbon to nitrogen ratio is 4.5, consistent with the ratio of 4 expected for the TMA cation.

[0065] Chemical stability and cation exchange capacity of 1DL NF We found that the TMA present after washing with EOH up to pH 7 + The cation is Li + It was confirmed that ion exchange with Li was easily possible. + Show that the cation can be exchanged with the following cation: H + , Na + , Mg 2+ , Mn 2+ , Fe 2+ , Co 2+ , Ni 2+ , and Zn 2+ The XRD patterns after ion exchange are plotted in Figures 11a–c. Typical SEM micrographs of the MPPs are shown in Figures 11d–k. Figures 19a–c plot the same data as Figures 11a–c, respectively, but on a logarithmic scale.

[0066] As mentioned in the experimental section, after ion exchange, all powders were washed multiple times with pure water and then dried at 50 °C in air before further characterization. In all cases, the absence of XRD peaks other than 1DL (Figures 11a-c and 19a-c) confirmed that most of the unreacted salts and unwanted reaction products were successfully removed. This also suggests that the unwanted reaction products are water-soluble.

[0067] After EtOH washing (blue patterns in Figures 11c and 19a), the first peak at ~7.5°2θ corresponds to the O10 basal reflection with d~11.5 Å. This d-spacing, together with the intercalated ions and water, is a measure of the thickness of the NFs along the b direction. From DFT calculations, we know that the thickness of one NF along the b direction is (7 Å), so the TMA + , the thickness of the HO is (4.5 Å), which is reasonable.

[0068] After washing with LiCl or NaCl solution (black and green patterns in Figures 11a and 19a, respectively), the d-spacings were reduced to 9.5 Å and 9.0 Å, respectively, and the TMA + The ions are Li + ion or Na + It was confirmed that the ions were successfully exchanged with Na. + , Li + The slightly larger d-spacing of the Li-intercalated powder likely reflects a slightly larger hydration shell in the former (see TGA results in Figure 23). Again, assuming the thickness of one NF along the b direction is (7 Å), the Li + +H2O and Na + The thicknesses of +H2O are 2.5 Å and 2.0 Å, respectively.

[0069] Figure 11b shows the XRD patterns of the powders that were first washed with LiCl solution and then treated with HNO3 or MgCl2 aqueous solution. The XRD patterns of the remaining cations are plotted in Figure 11c. The initial d-spacing is Li + For the intercalated NF, the peak was 9.5 Å (top black pattern in Figures 11b and 11c). When stirred in 0.1 M nitric acid, the 9.5 Å peak shifted slightly to 9.3 Å (red pattern in Figure 11b). Similarly, the peak of Li + When the NFs intercalated with Li were stirred in a 0.02MgCl solution (green pattern in Fig. 11b), the d-spacing expanded from 9.5 Å to 10.8 Å. + Ions are Mg 2+ This is considered to be evidence of an exchange.

[0070] Other divalent cations (Mn 2+ , Fe 2+ The situation is similar for Li + , on the other hand, Mn 2+ , Fe 2+ , Co 2+ , Ni 2+ , and Zn 2+Cation exchange between Mn and Mn occurs when the LiCl-washed powder is further treated with a 0.02 M aqueous solution of the cation of interest. As shown in Figure 11c, the d-spacing after cation exchange is 2+ , Fe 2+ , Co 2+ , Ni 2+ , and Zn 2+ For the intercalated 1DL NF, they were 11.4 Å, 10.7 Å, 9.8 Å, 9.4 Å, and 8.9 Å, respectively.

[0071] Interestingly, the EtOH-washed powder was directly treated with TMA + Li + When the samples were immersed in HNO, CoCl, or NiCl aqueous solutions for more than 24 hours without any exchange, the low-angle peaks disappeared (Figure 20a). The only remaining peaks were three non-basal reflections at 2θ values ​​of (26°), (48°), and (62°) (red bands in Figure 20a). SEM micrographs of the NiCl-washed samples (Figure 20b) confirmed that the morphology of the MPPs had changed to nanometer-sized, slightly porous aggregates.

[0072] To summarize this section, the interfilamentary spaces between 1DL NFs are filled with monovalent cations (HO + , Li + , and Na + ) and divalent cations (Mg 2+ , Mn 2+ , Fe 2+ , Co 2+ , Ni 2+ , and Zn 2+ ) are very readily exchangeable with 1DL. The corresponding XRD patterns clearly demonstrated the successful intercalation of these cations, as evidenced by the slight shift of the low-angle (<10°) 2θ peaks. It is noteworthy here that the non-basal peaks located at 48° and 62° 2θ (red dashed lines / bands in Figures 11a-c and Figures 19a-c) line up perfectly in all cases, regardless of the nature of the intercalant. This result indirectly supports the correctness of the assignment of these peaks to the 1DL framework (see below).

[0073] Surface charge and hydrodynamic size of NFs aggregates One of the aims of this study was to prepare NF and TMA. + or Li + The purpose of this study was to investigate the surface charge and aggregation behavior of cation-intercalated NF-based MPPs. To this end, the zeta potential ζ and hydrodynamic diameter d of the powders were measured. H The ζ potential and d were measured after washing with EtOH and LiCl solution. Except for the first sample (top row in Table 1) washed and measured with EtOH, all other samples were washed with the solvent / solution listed in the first column of Table 1, then dispersed in pure water. H All measurements were repeated three times and the results were averaged (see Figure 12) and summarized in Table 1 below.

[0074] [Table 1]

[0075] When the solvent was EtOH, the ζ-potential of MPP was −5±1.5 mV, explaining the instability of the colloid in this solvent. MPP settled to the bottom of the container (Figure 21a), and H Only particles / entities with a size of ~0.1 μm remained suspended (right axis in Figure 12). When MPP was dispersed in pure water, a ζ-potential of -53 ± 10 mV was recorded, resulting in a highly stable colloidal suspension (see Figure 21b). The high surface charge stabilized 1DL NF aggregates with a size of 2 ± 0.8 μm (right axis in Figure 12). The size of these aggregates is a function of colloid concentration. When MPP immediately after EtOH washing was washed with aqueous LiCl, the ζ-potential value decreased from -53 ± 10 mV in pure water to -33 ± 1.3 mV in 0.05 M LiCl (Figure 12 and Table 1). As the molar number of the aqueous LiCl solution increased from 0.5 M to 5 M, the ζ-potential changed slightly to -28 ± 0.5 mV (Figure 12 and Table 1 above).

[0076] When MPP was dried at 50°C (after washing with ethanol to neutrality) and redispersed in pure water, the pH increased significantly to about 10. - and / or OH - This could be due to proton uptake by the surface termination, but in our case, no change was observed in the low-angle peaks, suggesting that the surface oxygen atoms were hydroxylated by protonation.

[0077] In summary, after neutralization with EtOH, the ζ potential became slightly negative, and most of the MPPs precipitated (Figure 21c). Only aggregates smaller than 1.4 μm floated in EtOH (Figure 12). After washing with water, the ζ potential became significantly more negative (-50 ± 10 mV), explaining the colloidal stability in water.

[0078] The large drop in surface charge from DI water to 0.05M LiCl aqueous solution is essentially due to Li + This corresponds to electrostatic adsorption of ions onto the negatively charged NF surface. As a result, the electric double layer decreased, and the repulsive electrostatic interactions between NFs decreased. The decrease in surface charge as the molar concentration increased from 0.05 M to 5 M (Figure 12 and Table 1) is further evidence that the thickness of the diffusion layer of 1DL NFs decreased as the ionic strength increased.

[0079] Thermal stability of 1DL NF TMA + , Li + , or Na + The thermal stability of MPP was investigated up to 800 °C in Ar using thermogravimetric analysis (TGA) of NF intercalated with PEG. All powders were dried at 50 °C in air for 24 h before the TGA experiments. The TGA results were different for the EtOH- and salt-washed samples (Figure 23a). The latter showed a weight loss up to around 250 °C, after which it plateaued. The weight change at this temperature was mainly due to the loss of HO. 26 Washing with LiCl results in a slightly higher weight loss (18%) than washing with NaCl (15%) (Figure 23a).

[0080] Wash with EtOH and TMA + When the intercalated NFs were heated to 200 °C, a mass loss of (15%) was observed, likely due to residual EtOH solvent from washing (Figure 23a). Further heating at (350 °C) resulted in a mass loss of (15%), likely due to the loss of the hydration layer between the NFs and the intercalated TMA cations (Figure 23a). The XRD pattern did not change upon heating to 200 °C (Figure 23b). At higher magnification (Figure 24f), some of the NFs began to spheroidize / coarsen.

[0081] When the LiCl-washed MPP was heated, a single mass loss of 17 wt.% was observed up to 200 °C (Figure 23a), likely corresponding to the loss of Li cations and / or the hydration layer associated with dehydrogenation. The NaCl-washed MPP showed a similar mass loss of approximately 14 wt.% up to 200 °C (Figure 23a). The higher mass loss for the LiCl-washed sample (17%) suggests that the number of water molecules bound to the Li ions is slightly greater than that for the Na ions, which show a weight loss of 15%. Further heating of the powder to 800 °C did not result in any further mass loss.

[0082] However, the XRD pattern shows that Li + This indicates that the Na-intercalated NF was transformed into Li2Ti2O4, a mixture of rutile and lithium titanate (green pattern in Figure 23c). + -Intercalated NF is a mixture of rutile and sodium titanate, Na2Ti6O 13 It changed to.

[0083] Morphology, formation mechanism, and self-assembly of 1DL NFs Where the reaction occurs and its nature Here, the XRD patterns of samples reacted for 1–5 days, shown in Figure 9a, reveal the presence of a strong TiB2 peak (dashed black line in Figure 9a) early on. The corresponding SEM micrographs (Figures 13 and 25) clearly show that the MPPs surface appears identical at all magnifications, regardless of reaction time. This is a useful observation because it indicates that the conversion of TiB2 to 1DL begins at the surface and migrates inward toward the central core over time. This also suggests that, at least initially, the reaction must be surface-kinetically controlled (see Figure 26). Figure 14a is a schematic representation of what is imagined to occur at the interface. First, Ti atoms are released into the reaction medium and transformed into TiO6 octahedra. The latter then intercalates between the retreating substrate and the growing 1DL. The implications of this conclusion are useful because, in principle, the formation of core-shell structures is possible.

[0084] "One of the major drawbacks of working with nanomaterials in general, and nanoparticles in particular, is that nanoparticles, which typically require considerable effort to produce, tend to agglomerate and require further processing to deagglomerate. The free-flow nature of our MPP represents a paradigm shift, as it combines many of the benefits of small particle size without the drawbacks."

[0085] Finally, the fact that NFs nucleate on the precursor surface may explain why such 1DL NFs have not been discovered before. Most previous sol-gel studies have started with an aqueous titanium source. We speculate that nucleating the reaction on a solid surface may result in NFs growing only one-dimensionally. Further research is needed here. However, what is unmistakable is that Ostwald ripening is occurring in this microstructure. The initial TiB2 primary particle size is in the 5 μm range, with very few particles larger than 10 μm. As shown in the inset in Figure 9b, the final size of the MPPs is larger. This result not only confirms Ostwald ripening as a mechanism, but also indicates that the final product, 1DL NFs, can dissolve and reform in the reaction medium.

[0086] In summary, we report the true large-scale synthesis of TiO2-based subnanostructures using a simple solution precipitation method at ambient pressure and temperatures below 100 °C. In our method, water-insoluble, inexpensive, commercially available Ti-containing powders (e.g., TiB2) are shaken in a TMAH aqueous solution in a plastic bottle at 80 °C for 1–5 days. The resulting powders are washed with EtOH and water using an overhead mixer and beaker, then dehydrated at 50 °C in air. No centrifugation or filtration is required for processing these nanomaterials, reducing production costs at an industrial scale. Low-magnification SEM imaging reveals that each particle has a sponge-like morphology with an average size of ~13 μm. Further investigation using HR-STEM and SAD patterns reveals that the building blocks of the MPPs are lepidocrocite-type titanate NFs with a cross-section of 5 × 7 Å. 2 The mesoporous morphology was stable up to 800°C according to the TGA results.

[0087] We further investigated the ability of NFs to intercalate various cations into the interfilamentary galleries. Here, we investigated the ability of NFs to intercalate various monovalent cations (HO) + , Li + , and Na + ) and divalent cations (Mg 2+ , Mn 2+ , Fe 2+ , Co 2+ , Ni 2+ , and Zn 2+ ) can be easily ion-exchanged.

[0088] Finally, we investigated the surface charge and hydrodynamic size of the self-assembled NFs and showed that the ζ-potential was less than -60 mV in pure water, resulting in highly stable colloidal suspensions.

[0089] Experimental procedure Materials synthesis and processing 1DL sample preparation Our scalable synthesis protocol involves mixing commercially available TiB2 (-325 mesh Thermo Scientific, PA, US) powder with aqueous TMAH solution (Alfa Aesar, 25 wt.% in DI water, 99.9999%) in a polyethylene bottle. The Ti:TMAH molar ratio was kept constant at 0.6. In a typical batch, 100 g of TiB2 powder was immersed in 900 mL of TMAH solution contained in five 250 mL polyethylene bottles. The bottles were then transferred to a temperature-controlled incubator / shaker (Labnet International Inc., NC, 211DS 49L Shaking Incubator) and shaken at 80 °C and 175 rpm for 1–5 days.

[0090] Washing Protocol After the reaction, the resulting precipitate was placed in a 1-L beaker, the powder was allowed to settle, and the supernatant was decanted and discarded. To wash away unreacted TMAH, EtOH (Decon Lab Inc., 200 proof) was added to the 1-L beaker again and stirred at room temperature for 1 to 2 hours using an overhead mixer (OSC-10L-200 rpm, LabFish, China). The powder was then allowed to settle again, and the excess TMAH was removed. + The EtOH supernatant, consisting of cations and other unwanted reaction products, was again discarded. This procedure was repeated multiple times until the pH reached 7. The powder was then dried overnight in 50°C air.

[0091] Synthesis of ion-intercalated 1DL NF To evaluate the ion-exchange capacity, some powders were further stirred in the wet state for three 6-hour periods on a stir plate in one of the following salt solutions: 0.5M LiCl, 5M LiCl, 0.5M NaCl, or 5M NaCl. After three 6-hour periods, the powders were washed three times with purified water to remove unreacted salts and / or reaction products. All salts were purchased from Alfa Aesar with a purity greater than 99%. The LiCl- and NaCl-treated powders were air-dried overnight at 50°C.

[0092] X-ray diffraction, XRD To obtain the XRD patterns, a diffractometer (Rigaku MiniFlex, Tokyo, Japan) operating with Cu Kα radiation (40 kV, 15 mA) was used. The powders were scanned in the range of 2–65° 2θ with a step size of 0.02° and a dwell time of 1 s.

[0093] scanning electron microscope Photomicrographs of the materials were taken using a scanning electron microscope (SEM) (Zeiss Supra 50 VP, Carl Zeiss SMT AG, Oberkochen, Germany) with settings of an in-lens detector, a 30 mm aperture, and an accelerating voltage of 3–5 kV.

[0094] Particle size distribution Particle size distribution was performed using ImageJ software by measuring both the minimum and maximum length of each particle for a total of 100 particles.

[0095] scanning transmission electron microscope The scanning transmission electron microscope (STEM) was an aberration-corrected cold-cathode field-emission JEOL ARM200CF, operated at a primary electron energy of 200 kV. For high-angle annular dark-field (HAADF) imaging, imaging and spectroscopy were performed with an emission current of 15 μA, an electron probe half-vergence angle of 24 mrad, and a detector inner angle of 68 mrad and outer angle of 280 mrad. For low-angle annular dark-field (LAADF) imaging, the inner and outer angles were 30 mrad and 120 mrad, respectively. Annular bright-field (ABF) imaging was performed with an outer angle of 23 mrad and an inner angle of 11 mrad.

[0096] For nanoscale element identification and quantification, the ARM200CF has a detector area of ​​100 mm 2 The detector will be equipped with an Oxford XMX100TLE X-ray windowless silicon drift detector (SDD).

[0097] STEM samples were prepared by drop-casting a 5 ml suspension of TiB2-derived powder in mEtOH (5 days, 80 °C) onto a 3 mm lacey carbon copper grid. The sample was then allowed to dry for 1 h before being inserted into the microscope column.

[0098] Electron Energy Loss Spectroscopy (EELS) EELS measurements were performed using a post-column Gatan Continuum GIF ER spectrometer with an electron probe half-convergence angle of 17.8 mrad and a collection angle of 53.4 mrad. In-situ cooling was performed using a Gatan 636 liquid nitrogen / N2 cold stage. To reduce latent water, the sample was heated to 100 °C for 1 h within the microscope column.

[0099] Zeta potential and particle size measurement Electrophoretic mobility measurements were performed using a Zetasizer (Nano-ZS, Malvern Panalytical, Malvern, UK). Electrophoretic mobility values ​​were converted to zeta potential (ζ) using the Smoluchowski model. Hydrodynamic diameter (dH) was also measured using dynamic light scattering (DLS) on the same instrument. The mean hydrodynamic diameter was calculated from the diffusion coefficient using the Strokes-Einstein equation. All measurements were performed at ambient conditions with an equilibration time of 120 seconds.

[0100] Thermogravimetric analysis, TGA A thermobalance (TA Instruments Q50, New Castle, DE, USA) was used for TGA analysis. The dried powder (∼40 mg) was loaded into a sapphire crucible and heated to 800 °C at 10 °C / min under an Ar flow of 10 mL / min, and then the system was allowed to cool naturally.

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[0102] Aspects The following aspects are illustrative and not intended to limit the scope of the disclosure or the appended claims. Any one or more parts of any one or more aspects may be combined with any one or more parts of any one or more other aspects. Embodiment 1. A composition comprising a plurality of metal oxide sub-nanofilaments and / or nanofilaments, said sub-nanofilaments and / or nanofilaments optionally comprising lepidocrocite domains, said plurality of metal oxide sub-nanofilaments and / or nanofilaments optionally comprising an amount of carbon, said plurality of metal oxide sub-nanofilaments and / or nanofilaments optionally being configured in bundles, flakes, or both flakes and bundles. Embodiment 2. The composition of embodiment 1, wherein at least some of the nanofilaments and / or sub-nanofilaments have widths ranging from about 3 to about 50 Å, e.g., from about 7 to about 20 Å. Embodiment 3. The composition of embodiment 1, wherein at least some of the nanofilaments and / or sub-nanofilaments comprise Ti atoms. The Ti atoms can be, for example, arranged in a zigzag pattern. Embodiment 4. The composition of embodiment 1, wherein the nanofilaments and / or sub-nanofilaments define a non-circular cross-section. Such a cross-section can be, for example, elliptical. Embodiment 5. The composition of claim 4, wherein the nanofilaments and / or sub-nanofilaments define a cross-sectional aspect ratio of from 1 to greater than about 10. Embodiment 6. The composition of embodiment 5, wherein the nanofilaments and / or sub-nanofilaments define a cross-sectional aspect ratio of from about 2 to about 5. Aspect 7. The composition of aspect 1, wherein the nanofilaments and / or sub-nanofilaments are from about 10 to about 100 Å. 2 The composition has an average cross-sectional area in the range of Embodiment 8. The composition of embodiment 1, wherein at least some of the nanofilaments and / or sub-nanofilaments have a length in the range of 1 nm to about 25 μm. Embodiment 9. The composition of embodiment 8, wherein at least some of the nanofilaments and / or sub-nanofilaments have a length in the range of 1 nm to about 1 μm. Embodiment 10. The composition of embodiment 1, wherein the nanofilaments and / or sub-nanofilaments are comprised of a plurality of flakes. Embodiment 11. The composition of embodiment 1, wherein at least a portion of the plurality of nanofilaments and / or sub-nanofilaments lie in a common plane. Embodiment 12. The composition of any one of Embodiments 1 to 11, further comprising a pharmaceutically acceptable carrier. Embodiment 13. The composition of embodiment 1, further comprising a binder. Embodiment 14. The composition of embodiment 13, wherein the binder comprises a polymer. Embodiment 15. A device comprising the composition of embodiment 1. Aspect 16. The device of aspect 15, wherein the device is an energy storage device. Embodiment 17. The device of embodiment 15, wherein the device comprises an electrode. Embodiment 18. The device of embodiment 17, wherein the electrode comprises the composition of embodiment 1. Embodiment 19. The device of embodiment 15, wherein the device comprises a dispenser, the dispenser disposing the composition of embodiment 1 therein. Embodiment 20. A method comprising contacting a mono-, di-, tri-, or higher valent carbide, nitride, boride, phosphide, aluminide, or silicide, or titanium metal with a quaternary ammonium salt and / or a base, wherein the mono-, di-, tri-, or higher valent carbide, nitride, boride, phosphide, aluminide, or silicide, or titanium metal is optionally water-insoluble, and the water-insoluble di-, tri-, or higher valent carbide, nitride, boride, phosphide, aluminide, or silicide optionally comprises a transition metal, and the transition metal optionally comprises titanium, and wherein the contacting is performed under conditions sufficient to produce a nanofilamentary product. Aspect 21. The method of Aspect 20, wherein the conditions comprise a temperature of 0 to 100°C for about 5 hours to about 1 week. Aspect 22. The method of aspect 20, comprising contacting a divalent, trivalent, or higher boride with a quaternary ammonium salt and / or a base to produce nanofilamentary products. Embodiment 23. The method of embodiment 22, wherein the divalent boride comprises one or more titanium borides. Aspect 24 The method of aspect 22, wherein the quaternary ammonium salt and / or base comprises ammonium hydroxide, ammonium halide, or any combination thereof. Aspect 25. The method of aspect 24, wherein the ammonium hydroxide comprises tetramethylammonium hydroxide (TMAOH), tetraethylammonium hydroxide (TEAOH), tetrapropylammonium hydroxide (TPAOH), tetrabutylammonium hydroxide (TBAOH), ammonium hydroxide (NHOH), an amine derivative thereof, or any combination thereof. Embodiment 26. The method of embodiment 24, wherein the quaternary ammonium salt comprises a quaternary ammonium chloride, a quaternary ammonium bromide, a quaternary ammonium iodide, a quaternary ammonium fluoride, or any combination thereof. Aspect 27. The method of aspect 20, further comprising filtering the product. Embodiment 28. The method of embodiment 20, further comprising washing the article with a metal salt and / or other water-soluble metal compound. Embodiment 29. The method of embodiment 20, further comprising washing the article with a metal salt and / or a water-soluble metal compound, wherein the metal salt optionally comprises a metal sulfate, a metal nitrate, a metal chromate, a metal acetate, a metal carbonate, a metal permanganate, or a metal hydroxide, or any combination thereof. Aspect 30. The method of aspect 29, wherein the metal in the metal salt comprises Li, Na, K, Cs, Mg, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Nb, Mo, Cd, Ta, or W, or any combination thereof. Embodiment 31. The method of embodiment 29, wherein the metal salt comprises LiCl, KCl, NaCl, CsCl, LiF, KF, NaF, LiOH, KOH, NaOH, or any combination thereof. Aspect 32. The method of aspect 29, wherein the metal salt comprises CrCl3, MnCl2, FeCl2, FeCl3, CoCl2, NiCl2, MoCl5, FeSO4, (NH4)2Fe(SO4)2, CuCl2, CuCl, ZnCl2, or any combination thereof. Aspect 33. The method of aspect 20, wherein the product is the composition of aspect 1. Embodiment 34. A method comprising contacting particulate TiO2 with a quaternary ammonium salt and / or a base, said contacting being carried out under conditions sufficient to produce nanoparticle products, optionally wherein at least some of the nanoparticles have a diameter of from about 2 nm to about 1000 nm, optionally from about 10 nm to about 100 nm. Embodiment 35. The method of embodiment 34, wherein the quaternary ammonium salt and / or base comprises ammonium hydroxide, ammonium halide, or any combination thereof. Embodiment 36. The method of embodiment 34, wherein the quaternary ammonium base comprises tetramethylammonium hydroxide (TMAOH), tetraethylammonium hydroxide (TEAOH), tetrapropylammonium hydroxide (TPAOH), tetrabutylammonium hydroxide (TBAOH), ammonium hydroxide (NH4OH), an amine derivative thereof, or any combination thereof. Embodiment 37. The method of embodiment 34, wherein the quaternary ammonium salt comprises a quaternary ammonium chloride, a quaternary ammonium bromide, a quaternary ammonium iodide, a quaternary ammonium fluoride, or any combination thereof, along with a base. Aspect 38. The method of aspect 34, further comprising filtering the product. Embodiment 39. A composition comprising a population of nanoparticles produced according to the method of embodiment 34. Embodiment 40. A method comprising replacing TiO2 with a population of nanoparticles produced according to embodiment 34. Embodiment 41. A method comprising contacting a mono-, di-, tri-, or higher valent carbide, nitride, boride, phosphide, aluminide, silicide, or titanium metal with a quaternary ammonium salt and / or a base, wherein the mono-, di-, tri-, or higher valent carbide, nitride, boride, phosphide, aluminide, silicide, or titanium metal is optionally water-insoluble, and the water-insoluble di-, tri-, or higher valent carbide, nitride, boride, phosphide, aluminide, or silicide optionally comprises a transition metal, which optionally comprises titanium, wherein the contacting optionally occurs with shaking, and wherein the contacting occurs under conditions sufficient to produce mesoporous particles. Embodiment 42. A method comprising contacting a mono-, di-, tri-, or higher valent carbide, nitride, boride, phosphide, aluminide, silicide, or titanium metal with a quaternary ammonium salt and / or a base, wherein the mono-, di-, tri-, or higher valent carbide, nitride, boride, phosphide, aluminide, silicide, or titanium metal is optionally water-insoluble, and the water-insoluble di-, tri-, or higher valent carbide, nitride, boride, phosphide, aluminide, or silicide optionally comprises a transition metal, which optionally comprises titanium, wherein the contacting, optionally with agitation, and followed by washing with at least one salt, is performed under conditions sufficient to produce mesoporous particles. Embodiment 43. A method comprising contacting the monovalent, divalent, trivalent, or higher valent carbide, nitride, boride, phosphide, aluminide, silicide, or titanium metal with a quaternary ammonium salt and / or a base, wherein the monovalent, divalent, trivalent, or higher valent carbide, nitride, boride, phosphide, aluminide, silicide, or titanium metal is optionally water-insoluble, and the water-insoluble divalent, trivalent, or higher valent carbide, nitride, boride, phosphide, aluminide, or silicide optionally comprises a transition metal, which transition metal optionally comprises titanium, at a temperature of about 50 to about 95°C with shaking, and then washing with LiCl to produce mesoporous particles. Embodiment 44. A composition comprising mesoporous particles produced according to any one of embodiments 41-43. Embodiment 45. The composition of embodiment 44, further comprising a therapeutic agent. Embodiment 46. An electrode, the electrode comprising the composition of embodiment 44. Aspect 47. A device, the device comprising the composition of aspect 44. Aspect 48. The device of aspect 47, wherein the device is an energy storage device. Aspect 49. A method, said method comprising operating the apparatus of aspect 47. Embodiment 50. A mesoporous particle comprising a plurality of lepidocrocite nanofilaments, said plurality of lepidocrocite nanofilaments optionally comprising Ti, said mesoporous particle having a diameter of about 1 to about 30 μm. Embodiment 51. The mesoporous particle of embodiment 50, wherein the mesoporous particle has a diameter of from about 2 to about 25 μm. Embodiment 52. The mesoporous particle of embodiment 50, wherein the nanofilaments comprise a plurality of Ti atoms arranged in a zigzag pattern. Aspect 53. A composition comprising a plurality of mesoporous particles according to aspect 50. Aspect 54. A colloid, said colloid comprising a plurality of mesoporous particles according to aspect 50. Embodiment 55. The colloid of embodiment 54, wherein the plurality of mesoporous particles are suspended in water. Aspect 56. The colloid of aspect 54, wherein the plurality of mesoporous particles are suspended in an aqueous medium.

Claims

1. A composition, A composition comprising multiple metal oxide sub-nanofilaments and / or nanofilaments.

2. The composition according to claim 1, wherein the sub-nanofilament and / or nanofilament comprises a lepidocrocite region.

3. The composition according to claim 1, wherein the plurality of metal oxide sub-nanofilaments and / or nanofilaments comprise a quantity of carbon.

4. The composition according to claim 1, wherein the plurality of metal oxide sub-nanofilaments and / or nanofilaments are arranged in bundles, flakes, or both flakes and bundles.

5. The composition according to claim 1, wherein at least a portion of the nanofilaments and / or sub-nanofilaments have a width in the range of about 3 to about 50 Å.

6. A composition according to claim 1, wherein at least a portion of the nanofilaments and / or sub-nanofilaments contains Ti atoms.

7. A composition according to claim 1, wherein the nanofilaments and / or sub-nanofilaments define a non-circular cross-section.

8. The composition according to claim 7, wherein the nanofilaments and / or sub-nanofilaments define a cross-sectional aspect ratio greater than 1 and about 10 or less.

9. The composition according to claim 8, wherein the nanofilaments and / or sub-nanofilaments define a cross-sectional aspect ratio of about 2 to about 5.

10. In the composition according to claim 1, the nanofilaments and / or sub-nanofilaments are approximately 10 to approximately 100 Å in size. ２ A composition having an average cross-sectional area within the range of [a certain range].

11. The composition according to claim 1, wherein at least a portion of the nanofilaments and / or sub-nanofilaments have a length in the range of 1 nm to about 25 μm.

12. The composition according to claim 11, wherein at least a portion of the nanofilaments and / or sub-nanofilaments have a length in the range of 1 nm to about 1 μm.

13. A composition according to claim 1, wherein the nanofilaments and / or sub-nanofilaments are composed of a plurality of flakes.

14. A composition according to claim 1, wherein at least a portion of the plurality of nanofilaments and / or sub-nanofilaments are in a common plane.

15. A composition according to any one of claims 1 to 14, further comprising a pharmaceutically acceptable carrier.

16. A composition according to claim 1, further comprising a binder.

17. A composition according to claim 16, wherein the binder comprises a polymer.

18. An apparatus comprising the composition described in claim 1.

19. The apparatus according to claim 18, characterized in that the apparatus is an energy storage apparatus.

20. The apparatus according to claim 18, wherein the apparatus includes electrodes.

21. The apparatus according to claim 20, wherein the electrode contains the composition according to claim 1.

22. The apparatus according to claim 18, wherein the apparatus includes a dispenser, and the dispenser contains the composition according to claim 1.

23. It is a method, The process includes contacting a monovalent, divalent, trivalent, or higher carbide, nitride, boride, phosphide, aluminide, or silicide, or titanium metal, with a quaternary ammonium salt and / or base. The aforementioned monovalent, divalent, trivalent, or higher carbides, nitrides, borides, phosphides, aluminides, or silicides, or titanium metals, are optionally water-insoluble. Non-water-soluble divalent, trivalent, or higher carbides, nitrides, borides, phosphides, aluminides, or silicides optionally contain a transition metal, and the transition metal optionally contains titanium. The contact step is carried out under conditions sufficient to produce nanofilamentous products.

24. A method according to claim 23, wherein the conditions include a temperature of 0 to 100°C for about 5 hours to about 1 week.

25. A method according to claim 23, comprising the step of contacting a divalent, trivalent, or more boride with a quaternary ammonium salt and / or base to produce a nanofilamentous product.

26. The method according to claim 25, wherein the divalent boride comprises one or more titanium borides.

27. A method according to claim 25, wherein the quaternary ammonium salt and / or base comprises ammonium hydroxide, ammonium halide, or any combination thereof.

28. In the method according to claim 27, the ammonium hydroxide is tetramethylammonium hydroxide (TMAOH), tetraethylammonium hydroxide (TEAOH), tetrapropylammonium hydroxide (TPAOH), tetrabutylammonium hydroxide (TBAOH), ammonium hydroxide (NH ４ A method comprising OH), their amine derivatives, or any combination thereof.

29. The method according to claim 27, wherein the quaternary ammonium salt comprises a quaternary ammonium chloride, a quaternary ammonium bromide, a quaternary ammonium iodide, a quaternary ammonium fluoride, or any combination thereof.

30. A method according to claim 23, further comprising filtering the product.

31. A method according to claim 23, further comprising the step of washing the product with a metal salt and / or other water-soluble metal compound.

32. The method according to claim 23, further comprising the step of washing the product with a metal salt and / or a water-soluble metal compound, wherein the metal salt optionally includes metal sulfate, metal nitrate, metal chromate, metal acetate, metal carbonate, metal permanganate, or metal hydroxide, or any combination thereof.

33. The method according to claim 32, wherein the metal in the metal salt comprises Li, Na, K, Cs, Mg, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Nb, Mo, Cd, Ta, or W, or any combination thereof.

34. The method according to claim 32, wherein the metal salt comprises LiCl, KCl, NaCl, CsCl, LiF, KF, NaF, LiOH, KOH, NaOH, or any combination thereof.

35. In the method according to claim 32, wherein the metal salt is CrCl ３ , MnCl ２ , FeCl ２ , FeCl ３ , CoCl ２ , NiCl ２ , MoCl ５ , FeSO ４ , (NH ４ ), ２ Fe(SO ４ ), ２ , CuCl ２ , CuCl, ZnCl ２ or any combination thereof, the method.

36. A method according to claim 23, wherein the product is the composition described in claim 1.

37. It is a method, Particulate TiO ２ The process includes contacting with a quaternary ammonium salt and / or a base, The aforementioned contact step is carried out under conditions sufficient to produce nanoparticle products. The nanoparticle product optionally comprises at least some nanoparticles having a diameter of about 2 nm to about 1000 nm, and optionally about 10 nm to about 100 nm.

38. A method according to claim 37, wherein the quaternary ammonium salt and / or base comprises ammonium hydroxide, ammonium halide, or any combination thereof.

39. In the method according to claim 37, the quaternary ammonium base is tetramethylammonium hydroxide (TMAOH), tetraethylammonium hydroxide (TEAOH), tetrapropylammonium hydroxide (TPAOH), tetrabutylammonium hydroxide (TBAOH), ammonium hydroxide (NH ４ A method comprising OH), their amine derivatives, or any combination thereof.

40. A method according to claim 37, wherein the quaternary ammonium salt comprises, together with the base, a quaternary ammonium chloride, a quaternary ammonium bromide, a quaternary ammonium iodide, a quaternary ammonium fluoride, or any combination thereof.

41. A method according to claim 37, further comprising the step of filtering the product.

42. A composition comprising a group of nanoparticles produced according to the method of claim 37.

43. It is a method, TiO ２ A method comprising the step of replacing with a group of nanoparticles manufactured according to claim 37.

44. It is a method, The process includes contacting a monovalent, divalent, trivalent, or higher valent carbide, nitride, boride, phosphide, aluminide, silicide, or titanium metal with a quaternary ammonium salt and / or base. The aforementioned monovalent, divalent, trivalent, or higher valent carbides, nitrides, borides, phosphides, aluminides, silicides, or titanium metals are optionally water-insoluble. Non-water-soluble divalent, trivalent, or higher carbides, nitrides, borides, phosphides, aluminides, or silicides optionally contain a transition metal, and the transition metal optionally contains titanium. The aforementioned contact process may be performed while shaking, and The contact step is carried out under conditions sufficient to produce mesoporous particles, in a method.

45. It is a method, The process includes contacting a monovalent, divalent, trivalent, or higher valent carbide, nitride, boride, phosphide, aluminide, silicide, or titanium metal with a quaternary ammonium salt and / or base. Monovalent, divalent, trivalent, or higher valent carbides, nitrides, borides, phosphides, aluminides, silicides, or titanium metals are optionally water-insoluble. Non-water-soluble divalent, trivalent, or higher carbides, nitrides, borides, phosphides, aluminides, or silicides optionally contain a transition metal, and the transition metal optionally contains titanium. The contact step is carried out with optional shaking, and after contact, the particles are washed with at least one salt, under conditions sufficient to produce mesoporous particles.

46. It is a method, The process includes contacting a monovalent, divalent, trivalent, or higher valent carbide, nitride, boride, phosphide, aluminide, silicide, or titanium metal with a quaternary ammonium salt and / or base. The aforementioned monovalent, divalent, trivalent, or higher valent carbides, nitrides, borides, phosphides, aluminides, silicides, or titanium metals are optionally water-insoluble. Non-water-soluble divalent, trivalent, or higher carbides, nitrides, borides, phosphides, aluminides, or silicides optionally contain a transition metal, and the transition metal optionally contains titanium. A method for generating mesoporous particles by bringing the materials into contact with each other while shaking at a temperature of approximately 50 to 95°C, and then washing them with LiCl.

47. A composition comprising mesoporous particles manufactured according to any one of claims 44 to 46.

48. A composition according to claim 47, further comprising a therapeutic agent.

49. An electrode, wherein the electrode comprises the composition described in claim 47.

50. An apparatus comprising the composition described in claim 47.

51. The apparatus according to claim 50, wherein the apparatus is an energy storage apparatus.

52. A method, wherein the method includes the step of operating the apparatus described in claim 50.

53. Mesoporous particles, Containing multiple lepidocrocite nanofilaments, The plurality of lepidocrocite nanofilaments optionally contain Ti, The aforementioned mesoporous particle has a diameter of approximately 1 to approximately 30 μm.

54. A mesoporous particle according to claim 53, wherein the mesoporous particle has a diameter of about 2 to about 25 μm.

55. The mesoporous particle according to claim 53, wherein the nanofilament contains a plurality of Ti atoms arranged in a zigzag pattern.

56. A composition comprising a plurality of mesoporous particles as described in claim 53.

57. A colloid comprising a plurality of mesoporous particles as described in claim 53.

58. A colloid according to claim 57, wherein the plurality of mesoporous particles are suspended in water.

59. A colloid according to claim 57, wherein the plurality of mesoporous particles are suspended in an aqueous medium.

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