Oxide material

Abstract

This oxide material contains one or more types of materials selected from the group consisting of nanofibers, nanowires, and two-dimensional substances that are expressed by the formula MQaOb (in the formula, M is at least one type of element selected from the group consisting of groups 3, 4, 5, 6, and 7, Q is at least one type of element selected from the group consisting of groups 12, 13, 14, 15, and 16 (excluding O), a is a value of 0-2, and b is a value higher than 0 but no higher than 2), contains a metal element and / or a metalloid element on the surface and / or between layers thereof, and has a halogen element content of 0.90 mass% or less.

Description

oxide materials

[0001] The present disclosure relates to oxide materials.

[0002] Conventionally, as an oxide containing a metal, for example, TiO ２ In Non-Patent Document 1, 12 types of Ti compounds, including harmless precursors (TiC, TiN, etc.) that are abundant on Earth, are classified into TiO ２ A method for converting the TiO-based one-dimensional (1D) nanofilaments (NFs) has been proposed. ２ The based one-dimensional (1D) nanofilaments (NFs) have been shown to have potential applications in fields such as photocatalysis, dye degradation, batteries, and supercapacitors.

[0003] Hussein O. Badr et al., "On the structure of one-dimensional TiO2 lepidocrocite" Matter 6, 128-141, January 4, 2023

[0004] The TiO ２ The base one-dimensional (1D) nanofilaments (NFs) are unstable, changing their crystal structure when exposed to physical stimuli such as laser light or heat. It is thought that a change in the crystal structure can alter the functions they exhibit. For example, in the case of TiCO, the Raman spectrum changes when exposed to a 532 nm laser beam to increase the light intensity or when heated to 500°C. Based on the spectral attribution, the crystal structure changes from lepidocrocite to anatase. However, for applications such as adsorbents, photocatalysts, and ion conductors, a lepidocrocite crystal structure is preferable because it has a larger effective interlayer space and specific surface area than anatase, and thus exhibits higher adsorption capacity, catalytic activity, and ionic conductivity. Therefore, an oxide material with a lepidocrocite crystal structure that maintains its lepidocrocite structure without changing even when exposed to the laser beam or heated to 500°C is desired.

[0005] The present disclosure has been made in consideration of the above circumstances, and its purpose is to provide an oxide material whose crystal structure is lepidocrocite-type and which can maintain its lepidocrocite-type structure without changing even when irradiated with strong laser light or heated to a high temperature of 500°C.

[0006] According to one aspect of the present disclosure, a compound of the formula: ａ O ｂ (wherein M is at least one element selected from the group consisting of Groups 3, 4, 5, 6 and 7; Q is at least one element selected from the group consisting of Groups 12, 13, 14, 15 and 16 (excluding O); a is 0 or more and 2 or less; and b is 0 or more and 2 or less), the oxide material comprising one or more elements selected from the group consisting of nanofibers, nanowires and two-dimensional substances represented by the formula (wherein M is at least one element selected from the group consisting of Groups 3, 4, 5, 6 and 7; Q is at least one element selected from the group consisting of Groups 12, 13, 14, 15 and 16 (excluding O); a is 0 or more and 2 or less; and b is 0 or more and 2 or less), the oxide material comprising a metal element and / or a metalloid element on the surface and / or between layers, and the total content of halogen elements is 0.90 mass% or less.

[0007] According to the present disclosure, an oxide material is provided that does not change its crystal structure and can maintain its lepidocrocite structure even when the light intensity is increased, for example, by irradiating it with a 532 nm laser light, or when the temperature is raised to 500°C.

[0008] 1 is a schematic explanatory diagram illustrating the form of the material of this embodiment; FIG. 2 is a schematic explanatory diagram illustrating another form of the material of this embodiment; FIG. 3 is a schematic explanatory diagram illustrating another form of the material of this embodiment; FIG. 4 is an explanatory diagram of a representative atomic model of the material of this embodiment; FIG. 5 is another explanatory diagram of a representative atomic model of the material of this embodiment; FIG. 6 is an explanatory diagram of a representative atomic model of the material of this embodiment; FIG. 7 is an explanatory diagram of a representative atomic model of an anatase type material; FIG. 8 is another explanatory diagram of a representative atomic model of the material of this embodiment; FIG. 9 is a Raman spectroscopic analysis result of a film after laser irradiation at each light intensity in Example 1; FIG. 10 is a Raman spectroscopic analysis result of a film heated to 500°C in Example 1; FIG. 11 is a Raman spectroscopic analysis result of a film heated to 500°C in Example 2; FIG. 12 is a Raman spectroscopic analysis result of a film heated to 500°C in Comparative Example 1; FIG. 13 is a Raman spectroscopic analysis result of a film after laser irradiation at each light intensity in Comparative Example 6.

[0009] This embodiment relates to an oxide material comprising one or more selected from the group consisting of nanofibers, nanowires, and two-dimensional materials of a specific material, containing metal and / or metalloid elements on the surface and / or between layers, and having a total halogen content of 0.90% by mass or less. In this disclosure, the term "material" refers to a material comprising one or more selected from the group consisting of nanofibers, nanowires, and two-dimensional materials (in other words, a material comprising at least one selected from the group consisting of nanofibers, nanowires, and two-dimensional materials). The term "oxide material" refers to a compound comprising oxygen and other elements. In this embodiment, a material comprising one or more selected from the group consisting of nanofibers, nanowires, and two-dimensional materials typically refers to a solid material that does not contain a binder (e.g., a polymer). In a narrow sense, a material comprising one or more selected from the group consisting of nanofibers, nanowires, and two-dimensional materials may refer to a material that essentially consists of one or more selected from the group consisting of nanofibers, nanowires, and two-dimensional materials (which may include other objects, impurities, etc. that may inevitably be mixed in). However, the material comprising one or more selected from the group consisting of nanofibers, nanowires, and two-dimensional materials is not limited to these.

[0010] The material of this embodiment is one or more selected from the group consisting of nanofibers, nanowires, and two-dimensional materials of a predetermined material (substance). The predetermined material that can be used in this embodiment is represented by the following formula (1): MQ ａ O ｂ... (1) (In the formula, M is at least one element selected from the group consisting of Groups 3, 4, 5, 6 and 7, and may include at least one element selected from the group consisting of so-called early transition metals, for example, Sc, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and Mn, and preferably at least one element selected from the group consisting of Ti, V, Cr, Mo and Mn; Q is at least one element selected from the group consisting of Groups 12, 13, 14, 15 and 16 (excluding O), and may include at least one element selected from the group consisting of B, C, N, Si, P and S; a is 0 or more and 2 or less; and b is 0 or more and 2 or less.)

[0011] The above-mentioned predetermined material will be hereinafter also referred to simply as "MQO." Examples of MQO include TiO ２ , TiCO, TiCON, VO ２ , VCO, VCON, CrO ２ , CrCO, CrCON, MoO ２ , MoCO, MoCON, MnO ２ , MnCO, MnCON, etc. For example, in formula (1), M may be Ti and Q may be C. Also, for example, in formula (1), a may not be 0.

[0012] MQO has a crystal structure different from the hexagonal system. Although the present embodiment is not bound by any theory, the crystal structure of MQO is currently considered to be anatase type, lepidocrocite type, or a mixture of these. As described above, the crystal structure of MQO is preferably lepidocrocite type.

[0013] MQO can be produced, for example, using a first raw material and a second raw material as follows: The first raw material contains at least M, and the second raw material contains at least Q, and the first raw material and the second raw material are capable of reacting in a protic solvent to produce MQO.

[0014] As the first raw material, a material represented by the following formula (2) can be used: M ｃ A １ｄ ... (2) (wherein M is as defined above, A １ is at least one element selected from the group consisting of Groups 12, 13, 14, 15, and 16, and may include, for example, at least one element selected from the group consisting of B, C, N, O, Si, P, and S; and c and d are each independently 1 to 5. However, the material represented by formula (2) must be different from the product MQO. The material represented by formula (2) may typically have no peak in its X-ray diffraction (XRD) pattern in a diffraction angle 2θ range of 2° to 12°.

[0015] Examples of the first raw material represented by formula (2) include TiB ２ , TiB, TiC, TiN, TiO ２ , Ti ５ Si ３ , Ti ２ SbP, VO ２ , V ２ O ４ , NbC, Nb ２ O ５ , MoO ２ , MoO ３ , MoS ２ , MnO ２ , Mn ３ O ４ , MnCO ３ MnO that can be used as the first raw material ２ In the XRD pattern, the material has a peak near 2θ=13° and no peak in the 2θ range of 2° or more and 12° or less.

[0016] Alternatively, or in addition to the above, a material represented by the following formula (3) (hereinafter also simply referred to as a "MAX phase" or "MAX raw material") may be used as the first raw material. ｍ A ２ X ｎ ...(3) (wherein M is as defined above, X is at least one element selected from the group consisting of C and N, n is 1 or more and 4 or less, m is greater than n and 5 or less, A ２is at least one element selected from the group consisting of Groups 12, 13, 14, 15 and 16, and is usually a Group A element, typically Group IIIA and Group IVA, and more particularly may include at least one element selected from the group consisting of Al, Ga, In, Tl, Si, Ge, Sn, Pb, P, As, S and Cd, preferably Al). The MAX phase is ｍ X ｎ (which may have a crystal lattice where each X is located in an octahedral array of M), ２ The MAX phase has a crystal structure in which layers composed of atoms are located. When m=n+1, typically, one layer of X atoms is located between each of n+1 layers of M atoms (collectively referred to as "M ｍ X ｎ layer), and the layer next to the n+1-th layer of M atoms is A ２ Atomic layer ("A ２ The MAX phase has repeating units arranged in "atomic layers." However, the MAX phase is not limited to this.

[0017] Examples of the first raw material represented by formula (3) include Ti ３ AlC ２ , Ti ３ GaC ２ , Ti ３ SiC ２ These include:

[0018] As the first raw material, the material represented by formula (2) and the material represented by formula (3) may be used together (for example, as a mixture).

[0019] As the second raw material, an ionically bondable substance having a carbon-containing group can be used. The ionically bondable substance having a carbon-containing group contains C. Examples of the ionically bondable substance include ammonium salts, phosphates, sulfates, etc.

[0020] More specifically, a quaternary ammonium salt may be used as the second raw material. Examples of quaternary ammonium salts include tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), tetrabutylammonium hydroxide (TBAH or TBAOH), benzyltrimethylammonium hydroxide, tetrabutylammonium fluoride (TBAF), tetrabutylammonium chloride (TBACl), tetrabutylammonium bromide (TBAB), tetrabutylammonium iodide (TBAI), benzyltriethylammonium chloride (BTEAC), hexadecyltrimethylammonium bromide, cetyltrimethylammonium bromide (CTAB), benzethonium chloride, benzalkonium chloride, and cetylpyridinium chloride (CPC). Among these, TMAH and TBAOH are preferred.

[0021] Alternatively, or in addition to the above, other ion-binding substances containing P and / or S, etc. may be used as the second raw material.

[0022] The protic solvent may be any solvent capable of at least partially dissolving the first and second raw materials, and may be, in particular, an aqueous solvent. Examples of the protic solvent include water, alcohol (e.g., ethanol, 1-propanol, isopropanol), and carboxylic acids (e.g., acetic acid and formic acid). The aqueous solvent may be composed of water and, optionally, a liquid substance compatible with water (e.g., a protic solvent other than water), and is preferably water.

[0023] The first and second raw materials are reacted in a protic solvent. The second raw material can be added to the protic solvent in advance. The ratio of the second raw material to the total of the protic solvent and the second raw material can be, for example, 5% by mass or more, particularly 20% by mass or more, and / or, for example, 80% by mass or less, particularly 50% by mass or less. The first raw material can be further added to the protic solvent to which the second raw material has been added, and mixed. In this mixture, a reaction to produce MQO proceeds. The temperature (reaction temperature) of the mixture (which may contain the reaction product) can be, for example, 15°C or more, particularly 40°C or more, and / or, for example, 100°C or less, particularly 80°C or less. The mixing time (reaction time) can be, for example, one day or more, particularly two days or more, and / or, for example, 10 days or less, particularly 7 days or less. Mixing can be performed, for example, by rotating a magnetic stirrer placed in a container while maintaining the reaction temperature using a hot plate stirrer and a warm water bath. However, the treatment operations and conditions (temperature, time, etc.) that can cause the reaction to proceed are not limited to those described above, and may be selected appropriately depending on the first raw material, second raw material, protic solvent, etc. that are used.

[0024] The above reaction produces MQO, which may eventually grow into MQO nanofibers and further MQO nanoflakes. FIGS. 1A to 1C are schematic diagrams illustrating the morphology of the material of this embodiment. While not limiting the present disclosure, the resulting MQO nanofibers may be in the form of nanoribbons extending in the

[100] direction (as shown in FIG. 1A ) with a nanoscale width (the width in the

[001] direction in FIG. 1A ), as shown in FIG. 1A . Alternatively, multiple MQO nanofibers (or nanoribbons) may bond and / or integrate with each other to grow into nanoflakes extending two-dimensionally. Alternatively, multiple MQO nanoflakes may overlap each other (e.g., by van der Waals forces) to form a stack, as shown in FIG. 1B . Alternatively, the nanoflakes may grow into layered nanoflakes extending two-dimensionally, as shown in FIG. 1C . Furthermore, the higher-order structure may be a porous body (e.g., particle shape or film shape) in which layered nanofibers are entangled with each other, or a layer structure in which layered nanoflakes are stacked in the thickness direction. Although the present disclosure is not bound by any theory, the generation and growth of such MQO may be thought to be due to a bottom-up synthesis reaction.

[0025] The mixture after the reaction (also referred to as a reaction mixture) may be subjected to appropriate post-treatment, such as washing, impact (including shear force), drying (e.g., freeze-drying or heat drying), or pulverization.

[0026] The washing may be carried out using a protic solvent. The same explanation as above may be applied to the protic solvent, and the protic solvent may be washed with, for example, water or alcohol. After washing, a separation operation (centrifugation and / or decantation) may be carried out. The washing and separation operations may be repeated until the pH of the supernatant after centrifugation is, for example, 8 or less.

[0027] Optionally, instead of or in addition to the above washing, washing may be carried out using an aqueous solution of a metal salt. The metal salt may be, for example, a hydroxide of an alkali metal (Li, Na, K, etc.) or a hydroxide of an alkaline earth metal (Mg, Ca, Sr, etc.), typically NaOH, LiOH, KOH, etc. Specifically, washing may be carried out using, for example, an aqueous solution of a metal salt having a concentration of 0.01 to 10 molar. After washing, a separation operation (centrifugation and / or decantation) may be carried out. In this case, too, the washing and separation operations may be repeated as necessary until the pH of the supernatant after centrifugation becomes, for example, 8 or less.

[0028] In some cases, instead of or in addition to the above washing, washing may be carried out using an aqueous solution of a metal salt. The metal salt may be, for example, a sulfate or nitrate of an alkali metal (Li, Na, K, etc.), a sulfate or nitrate of an alkaline earth metal (Mg, Ca, Sr, etc.), or a typical example is Na. ２ SO ４ , Li ２ SO ４ , KNO ３ etc. Specifically, washing may be carried out using, for example, an aqueous metal salt solution having a concentration of 0.01 to 10 molar. After washing, a separation operation (centrifugation and / or decantation) may be carried out. In this case, too, the washing and separation operations may be repeated as necessary until the pH of the supernatant after centrifugation becomes, for example, 8 or less.

[0029] Impact such as vibration and / or ultrasound may be applied during and / or after washing. This can promote the dispersion of MQO particles (e.g., nanofibers / nanoflakes, hereinafter the same). If the MQO particles are aggregated, they can be broken down. This effect is particularly pronounced when impact is applied during washing with an aqueous solution of a metal salt (it is believed that metal cations derived from the metal salt penetrate into the gaps between the aggregates and break them down). Impact can be applied using, for example, one or more of a handshake, an automatic shaker, a mechanical shaker, a vortex mixer, a homogenizer, an ultrasonic bath, etc.

[0030] Since the MQO particles are a solid component, a separation operation can be carried out at any appropriate time to remove unnecessary liquid components, if any. As a final separation operation, for example, a drying operation, typically freeze-drying or thermal drying, may be carried out. Freeze-drying can be carried out, for example, by freezing a mixture containing the MQO particles and a liquid component at any appropriate temperature (e.g., −40° C.) and then drying under reduced pressure. Thermal drying can be carried out, for example, by drying a mixture containing the MQO particles and a liquid component at a temperature of 25° C. or higher (e.g., 200° C. or lower) under atmospheric pressure or under reduced pressure. Pulverization can be carried out using, for example, a mortar and pestle combination, an IKA mill, or the like, without particular limitation. Pulverization may also be carried out after drying.

[0031] As described above, particles of MQO can be obtained as a material containing MQO. According to this embodiment, as described above, a material containing MQO can be easily produced, and a photocatalyst or the like that is the material containing MQO or that includes the material can be realized.

[0032] In the present disclosure, the cross-sectional outer dimension of an MQO nanofiber refers to the shortest distance passing through the center of a cross section transverse to the longitudinal direction of the MQO nanofiber. The cross-sectional shape of an MQO nanofiber is not particularly limited, but can be approximated, for example, by a rectangle (rectangle, square, etc.) or an ellipse (flattened circle, perfect circle, etc.). When an MQO nanofiber is in the form of a nanoribbon, the cross-sectional shape can be approximated by a rectangle, and the cross-sectional outer dimension can correspond to the length of the short side of the rectangle. When an MQO nanofiber is in the form of a nanofilament, the cross-sectional shape can be approximated by a flattened circle, and the cross-sectional outer dimension can correspond to the length of the short diameter of the flattened circle.

[0033] In the present disclosure, MQO is a solid content. MQO may typically be in the form of particles (or powder).

[0034] Although MQO is represented by formula (1), a material containing MQO (typically, MQO particles) does not necessarily have to consist solely of the constituent elements of formula (1). While not limiting the present disclosure, a material containing MQO may optionally have at least one modification or terminal T present on its surface selected from the group consisting of a hydroxyl group, a chlorine atom, an oxygen atom, a hydrogen atom, and a nitrogen atom. Furthermore, a material containing MQO (typically, MQO particles) may have two or more layers, and ions and / or atoms of a metal element and / or a metalloid element may be present between these layers. For example, at least one selected from the group consisting of an ammonium ion (e.g., a quaternary ammonium cation) and a metal cation (e.g., an alkali metal ion or an alkaline earth metal ion) may be present between these layers.

[0035] The particle size of the MQO particles may be, for example, 0.01 nm or more, in particular 0.1 nm or more, or even 1 nm or more, and / or may be, for example, less than 1000 nm, in particular 100 nm or less, or even 50 nm or less. Such particles may also be referred to as nanoparticles.

[0036] The particle form of the MQO is one or more selected from the group consisting of nanofibers, nanowires, and two-dimensional materials. The two-dimensional materials include one or more of nanoflakes and stacks of nanoflakes. In this embodiment, the two-dimensional materials are not limited to only nanoflakes and stacks of nanoflakes.

[0037] Nanofibers may also be referred to as nanowires. In the present disclosure, "nanofiber" refers to a solid object extending in the longitudinal direction, as shown in FIG. 1A, for example, in which the external dimensions of a cross section perpendicular to the longitudinal direction (cross-sectional external dimensions) are on the nano-order (i.e., 1 nm or more and less than 1000 nm) or even smaller, sub-nano-order (less than 1 nm, for example, 0.1 nm or more and less than 1 nm). The longitudinal length of a nanofiber is not limited to the nano-order (i.e., 1 nm or more and less than 1000 nm), but may be on the micron order (1 μm or more and less than 1000 μm). The cross-sectional external dimensions of a nanofiber may be, for example, 0.1 nm or more, particularly 1 nm or more, and may be, for example, 100 nm or less, particularly 50 nm or less, and preferably 15 nm or less.

[0038] In the present disclosure, the term "two-dimensional material" refers to a solid object having a two-dimensionally extending surface (also referred to as a plane or two-dimensional sheet surface), as shown in FIG. 1C , and a thickness that is relatively small compared to the maximum dimension of the surface (which may correspond to the "in-plane dimension" of a particle), with the thickness being on the nano-order (i.e., 1 nm or more but less than 1000 nm) or even smaller, on the sub-nano-order (less than 1 nm, e.g., 0.1 nm or more but less than 1 nm). The in-plane dimension is not limited to the nano-order (i.e., 1 nm or more but less than 1000 nm), but may be on the micron-order (1 μm or more but less than 1000 μm). As described above, two-dimensional materials include one or more of nanoflakes and stacks of nanoflakes. Nanoflakes may also be referred to as nanosheets or two-dimensional (nano)sheets. The thickness of one layer of nanoflakes may be, for example, 0.01 nm or more, particularly 0.8 nm or more, and may be, for example, 20 nm or less, particularly 3 nm or less. The in-plane dimensions of the nanoflakes may be, for example, 0.1 μm or more, in particular 1 μm or more, and may be, for example, 200 μm or less, in particular 40 μm or less. The nanoflakes may be composed of an aggregate of nanofibers.

[0039] The stack of nanoflakes may also be referred to as a multi-layer MQO. The distance (interlayer distance or gap size) between two adjacent nanoflakes (or two adjacent layers of MQO) is not particularly limited.

[0040] Representative atomic models of the material of this embodiment (more specifically MQO) are shown along

[100] ,

[010] , and

[001] , for example, in Figures 2-4. These figures are representative polyhedron diagrams of TiCO (TiO ２ In these figures, the number of atoms in each direction is not limited to this figure, and a suitable range of the length in each direction will be described later. ６ A layer is formed by octahedra lined up.

[0041] The length in the

[100] direction can be 10 nm to 10 μm, and the length in the

[100] direction is preferably 20 nm to 5 μm, more preferably 30 nm to 3 μm, so that the aqueous dispersion can be easily handled, that is, so that the viscosity of the aqueous dispersion falls within an appropriate range.

[0042] The length in the

[010] direction can be 1 nm to 5 μm. The length in the

[010] direction is preferably 3 nm to 1 μm, and more preferably 5 nm to 100 nm, so that the aqueous dispersion can be easily handled, that is, so that the viscosity of the aqueous dispersion falls within an appropriate range.

[0043] The length in the

[001] direction can be 0.1 nm to 100 nm. Furthermore, the length in the

[001] direction is preferably 0.5 nm to 50 nm, more preferably 1 nm to 30 nm, so that the aqueous dispersion can be easily handled, that is, so that the viscosity of the aqueous dispersion falls within an appropriate range. Furthermore, this range is preferable because it increases the specific surface area of ​​MQO.

[0044] Although not limiting the present disclosure, the resulting MQO nanofibers may be in the form of nanoribbons extending in nanoscale widths as described above, or may grow into two-dimensional nanoflakes, for example, with lengths in the

[100] and

[010] directions approximately equal (within a 20% error).

[0045] In the present disclosure, "interlayer" refers to the space between one layer and another adjacent layer in the

[010] direction in Figures 1A to 1C and Figures 2 to 7 (note that such a space is not formed in Figure 5). The interlayer distance is 0.01 nm to 100 nm. If the interlayer distance is too small, the specific surface area will decrease, and if the interlayer distance is too large, the van der Waals force between the layers will decrease, resulting in reduced structural stability. Therefore, the interlayer distance is preferably 0.1 nm to 50 nm, and more preferably 0.3 nm to 20 nm.

[0046] Although not limiting the present disclosure, the MQO in this embodiment may have lengths in the

[010] and

[001] directions on the order of nanometers. This is completely different from conventional layered materials, and the interlayer space may be almost entirely exposed to the surface. Therefore, the reaction efficiency in physical phenomena such as adsorption and in all chemical reactions may be higher than that of conventional layered materials. Furthermore, if the

[100] direction becomes the longitudinal direction on the order of micrometers, it may become a one-dimensional material with a layer structure in the

[010] direction.

[0047] The above is a typical example of MQO, lepidocrocite-type TiO ２ The atomic structure of MQO is explained below. However, MQO can be converted to anatase TiO by heat treatment etc. ２ In this case, as shown in Figure 5, the interlayer space existing in the

[010] direction disappears, resulting in a decrease in the specific surface area and a decrease in the efficiency of all physical phenomena and chemical reactions.

[0048] Although not limiting the present disclosure, the MQO in this embodiment may have different stacking states, for example, in the

[010] direction. For example, in FIG. 6, when any layer A in the

[010] direction is translated in the

[010] direction, which is perpendicular to a plane C parallel to the (0k0) plane existing in the space (interlayer) between adjacent layers B, its atomic configuration may overlap with layer B, which is called an AAA stack. At this time, the influence of interlayer ions and atomic defects may further promote energy minimization of the entire crystal, resulting in a different atomic configuration, i.e., a stable crystal structure. For example, when layer A is inverted with respect to the above-mentioned plane C and then translated in the

[010] direction, which is perpendicular to plane C, an ABA stack state may be considered, in which its atomic configuration overlaps with layer B. Considering the structural stability of layered materials, the ABA stack shown in FIG. 7 is known to be more stable than AAA. Specifically, the ABA stack structure has a specific symmetry, which uniforms interactions between layers (such as van der Waals forces and electrostatic attraction), resulting in a regular and efficient atomic arrangement due to the symmetry. For these reasons, the energy state and arrangement pattern within the crystal are stabilized, promoting energy minimization throughout the crystal structure and increasing stability. The AAA stack structure has a crystal structure contrary to the above, making it relatively sensitive to external factors and thermal energy, and presenting challenges in structural stability. However, the ABA stack structure, configured as described above, has higher resistance to external factors and thermal energy than the AAA stack structure. Therefore, the layered material of this embodiment can achieve its excellent stability and performance by adopting the ABA stack structure.

[0049] Each of the above dimensions can be determined as a number-average dimension (number average of at least 40 dimensions) based on a photograph observed with a scanning electron microscope (SEM), a transmission electron microscope (TEM), or an atomic force microscope (AFM) (after processing by a method such as focused ion beam (FIB) if necessary), or as a distance in real space calculated from the position in reciprocal lattice space of the (002) plane measured by X-ray diffraction (XRD).

[0050] However, it should be noted that in the present disclosure, the MQO is not limited to the above forms and may have any suitable form.

[0051] According to the research of the present inventors, in order to obtain the oxide material of this embodiment, a material containing MQO (one or more selected from the group consisting of nanofibers, nanowires, and two-dimensional materials) is immersed in, for example, an aqueous solution of lithium chloride (LiCl), and then a metal element and / or a metalloid element is further supplied, for example, hydroxides, sulfates, nitrates, etc. of one or more elements of alkali metals (Li, Na, K, etc.) and alkaline earth metals (Mg, Ca, Sr, etc.), typically LiOH, KOH, NaOH, Na ２ SO ４ , Li ２ SO ４ , KNO ３ In this way, tetramethylammonium (TMA) ions originating from the raw materials and originally contained in the MQO-containing material are temporarily substituted with lithium (Li), and then further substituted with a desired metal element and / or metalloid element, for example, an alkali metal element (Li, Na, K, etc.) and / or an alkaline earth metal element (Mg, Ca, Sr, etc.), and it has been found that even when exposed to, for example, irradiation with a strong laser beam or a high temperature of 500°C, the crystal structure of MQO does not change, maintains the lepidocrocite structure, and has a stable crystal structure, thereby obtaining the oxide material of this embodiment.

[0052] The content of metal elements and / or metalloid elements present on the surface and / or between layers is, for example, preferably 0.001 to 10 mass %, more preferably 0.1 to 8 mass %, and even more preferably 1 to 6 mass %.

[0053] As a specific example, research by the present inventors has revealed that when a material containing MQO (one or more selected from the group consisting of nanofibers, nanowires, and two-dimensional materials) is immersed in an aqueous potassium hydroxide (KOH) solution and then dried, and the trimethylammonium (TMA) ions originally contained therein are replaced with potassium (K), the crystal structure of MQO does not change, remains lepidocrocite-type, and is stable, even when irradiated with, for example, a 532 nm laser beam to increase the light intensity.

[0054] The oxide material of this embodiment contains a metal element and / or a metalloid element on the surface and / or between layers of the oxide material, which refers to, for example, the surface and / or between layers of a material containing MQO (one or more selected from the group consisting of nanofibers, nanowires, and two-dimensional materials).

[0055] Examples of metal elements include typical metal elements and transition metal elements from Groups 1 (excluding hydrogen) to 15 of the periodic table, and one or more of these elements may be used. Examples of metalloid elements include boron, silicon, germanium, arsenic, antimony, and tellurium, and one or more of these elements may be used. The metal elements and / or metalloid elements are preferably one or more elements selected from the group consisting of K, Na, Li, Ca, and Mg.

[0056] The oxide material of this embodiment has a total halogen element content of 0.90% by mass or less. In this embodiment, it has been discovered that by limiting the total halogen element content to 0.90% by mass or less, the lepidocrocite-type crystal structure can be maintained without transitioning from the lepidocrocite-type to the anatase-type crystal structure, even when irradiated with a strong laser beam or exposed to a high temperature of 500°C. The halogen element refers to an element in Group 17 of the periodic table. Particular examples of the halogen element include one or more elements selected from the group consisting of Cl, Br, F, I, and At. The total content of these elements can be limited to 0.90% by mass or less.

[0057] The halogen element may be contained in the oxide material, but the smaller the content, the better, preferably 0.50 mass% or less, more preferably 0.20 mass% or less, and most preferably zero. Note that, for example, depending on the halogen-containing raw material that can be used in the manufacturing process of the oxide material of this embodiment, the lower limit of the halogen element content may be 0.001 mass%. The location of the halogen element in the oxide material is not limited. The halogen element may be contained on the surface and / or between layers of the oxide material. Furthermore, the halogen element may interact with ions of metal elements and / or metalloid elements.

[0058] The oxide material of this embodiment has a crystal water content of 10 mass % or less. In this specification, "crystal water" refers to water molecules present inside the oxide material, particularly between layers of a material containing MQO. When crystal water is contained, as shown in the examples described later, when the temperature is increased from 50°C to 500°C at a rate of 10°C / min in a He atmosphere (flow rate 70 mL / min), the H ２ The amount of water of crystallization is confirmed as a peak of O gas. The amount of water of crystallization is calculated from this peak. By reducing the amount of water of crystallization contained in the oxide material, the crystal structure does not transition from lepidocrocite to anatase, and the lepidocrocite crystal structure can be maintained, even when exposed to strong laser light or high temperatures.

[0059] The water of crystallization may interact with ions and / or atoms of the metal element and / or metalloid element. The content of water of crystallization is preferably 5% by mass or less, more preferably 1% by mass or less, and even more preferably 0.5% by mass or less. The lower the content of water of crystallization, the better. However, due to factors such as the manufacturing process, the lower limit may be 0.001% by mass. The content of water of crystallization may be in the range of 0.001 to 10% by mass, preferably 0.001 to 1% by mass, and more preferably 0.001 to 0.5% by mass.

[0060] A material containing MQO may typically have a peak in the X-ray diffraction (XRD) pattern in the diffraction angle 2θ range of 2° to 12° (characteristic X-ray: CuKα = 1.54 Å). While the present disclosure is not bound by any theory, the presence of a peak in the XRD pattern of a material containing MQO in the 2θ range of 2° to 12° is believed to indicate that the MQO has a crystal structure different from that of well-known metal oxides. For example, the above-mentioned peak indicates the presence of a periodic structure in the [0k0] direction. Furthermore, the presence of peaks at 2θ = 26°, 2θ = 48°, and 2θ = 63° confirms that the MQO has the crystalline structure of lepidocrocite. Furthermore, the size of the d-spacing obtained from the peaks in the 2θ range of 2° to 12° can provide additional confirmation of the identity of the interlayer ionic species.

[0061] In the present disclosure, an XRD pattern is a pattern (the vertical axis represents intensity and the horizontal axis represents 2θ) obtained by scanning in the θ-axis direction with an XRD analyzer using CuKα radiation (approximately 1.54 Å) as characteristic X-rays, and may also be referred to as an “XRD profile.” Peaks in an XRD pattern can be identified visually or by using software used with the XRD analyzer.

[0062] Although this embodiment is not limited to this embodiment, for example, the material of this embodiment (more specifically, MQO) has a Raman shift of at least 275 to 295 cm in a Raman spectrum using a laser with a wavelength of 532 nm. －１ , 435-455cm －１ , and 665-745 cm －１ It may have a peak at the position

[0063] Although this embodiment is not limited to this embodiment, for example, the material of this embodiment (more specifically, MQO) has a Raman shift of 140 to 160 cm in a Raman spectrum using a laser with a wavelength of 532 nm. －１ , 275-295cm －１ , 435-455cm －１ , and 665-745 cm －１ It may have a peak at a position of 140 to 160 cm－１ is the peak of the anatase type.

[0064] Although this embodiment is not limited thereto, for example, the material of this embodiment (more specifically, MQO) has a crystal structure of anatase type, lepidocrocite type, or a mixture of these. More preferably, it has a crystal structure of lepidocrocite type.

[0065] Although this embodiment is not limited to this embodiment, for example, the material of this embodiment (more specifically, MQO) has a Raman shift of at least 275 to 295 cm in a Raman spectrum using a laser with a wavelength of 532 nm. －１ , 435-455cm －１ , and 665-745 cm －１ and when the intensities of the respective peaks are X, Y, and Z, X is the largest.

[0066] Although this embodiment is not limited thereto, more preferably, the material of this embodiment (more specifically, MQO) has a Raman shift of at least 180 to 200 cm in a Raman spectrum using a laser with a wavelength of 532 nm. －１ , 275-295cm －１ , 375-395cm －１ , 435-455cm －１ , and 665-745 cm －１ and when the intensities of the respective peaks are V, X, Y, Z, and W, X is the largest.

[0067] In this disclosure, the Raman spectrum is measured with a Raman spectrometer using a 532 nm laser as an excitation light source (the vertical axis represents intensity, and the horizontal axis represents Raman shift). Peaks in the Raman spectrum can be identified visually or by using software used with the Raman spectrometer.

[0068] Furthermore, the MQO-containing material may contain unreacted first and / or second raw materials as impurities, and may also contain substances derived from the first, second, and / or protic solvents. For example, when a quaternary ammonium salt is used as the second raw material, N may be present (residual) in any form in the MQO-containing material. While not limiting this embodiment, the MQO-containing material may contain ammonium ions or tetramethylammonium ions. Furthermore, for example, when a MAX raw material is used as the first raw material, the MQO-containing material in this disclosure may contain a relatively small amount of residual A atoms, for example, 10% by mass or less relative to the original A atoms. The amount of residual A atoms may preferably be 8% by mass or less, more preferably 6% by mass or less. However, even if the amount of residual A atoms exceeds 10% by mass, this may not be a problem depending on the usage conditions, etc.

[0069] To obtain a material containing MQO with higher purity, it is preferable to repeat washing and centrifugation multiple times and recover the supernatant after the final centrifugation. Such supernatant can be used as is, appropriately diluted with a liquid medium, or dried and then mixed with a liquid medium to form a slurry containing MQO particles.

[0070] Although the materials in certain embodiments of the present disclosure have been described in detail above, various modifications of the present disclosure are possible. Note that the materials of the present disclosure may be manufactured by methods different from the manufacturing methods in the above-described embodiments.

[0071] (Example 1) Preparation of a slurry containing TiCO First, titanium diboride (TiB ２1 g of ethanol (manufactured by Alfa Aesar) and 10 mL of 25% by weight tetramethylammonium hydroxide (TMAH) aqueous solution (manufactured by Alfa Aesar) were added to the container. A stirrer tip with a length (35 mm) approximately equal to the inner diameter of the circular bottom of the container was placed therein. The container was maintained at 80°C in an oil bath, and the mixture in the container was stirred with the stirrer tip for 120 hours, allowing the reaction to proceed. The reaction mixture in the container was then transferred to a centrifuge tube. The solids were then precipitated by centrifugation at 3500 G for 5 minutes. (i) After centrifugation, the supernatant was discarded. (ii) 40 mL of ethanol (manufactured by Fisher Chemical) was added to the remaining sediment in the centrifuge tube, and the mixture was dispersed using a vortex mixer for 5 minutes (reslurry). (iii) The centrifugation was repeated under the same conditions as above. These steps (i) to (iii) were repeated until the pH of the supernatant reached 8 or below. After repeating the process three times, the pH of the supernatant became 8 or less, so the supernatant was discarded and the repeating operation was terminated. 40 mL of pure water was added to the remaining sediment in the centrifuge tube, and the mixture was shaken and stirred for 5 minutes using a vortex mixer. Then, the mixture was centrifuged at 3500 G for 30 minutes using a centrifuge, and the supernatant was collected as a sample slurry. The obtained sample slurry corresponds to a slurry containing TiCO.

[0072] - Preparation of TiCO Film A TiCO film was prepared using the above-mentioned TiCO-containing slurry as follows. 1 mL of the above-mentioned TiCO-containing slurry was taken and mixed with 20 mL of pure water, and then vibrated in a vortex mixer for 5 minutes. The resulting mixture was suction filtered overnight using a Nutsche filter. A membrane filter (Durapore, pore size 0.22 μm, manufactured by Merck Ltd.) was used as the suction filtration filter. After suction filtration, the precursor film on the filter was dried overnight at 80 °C in a vacuum oven, and the filter was removed to obtain a film (free-standing film).

[0073] - Preparation of film immersed in aqueous lithium chloride (LiCl) solution A 1 M aqueous lithium chloride solution was placed in a petri dish, and the above film (freestanding film) was immersed in it for 10 minutes. The film was then removed from the aqueous lithium chloride solution, and the film surface was rinsed with pure water to remove excess lithium chloride from the film surface. Washing was repeated until the pH of the washing liquid reached 7. Water droplets on the film surface were then gently wiped off with a cloth, completing a film immersed in an aqueous lithium chloride solution.

[0074] Preparation of a film immersed in a sodium hydroxide (NaOH) aqueous solution: A 1M sodium hydroxide aqueous solution was placed in a petri dish, and the above-mentioned film immersed in a lithium chloride aqueous solution was immersed in it for 10 minutes. The film was then removed from the sodium hydroxide aqueous solution, and the film surface was rinsed with pure water to remove excess sodium hydroxide from the film surface. Washing was repeated until the pH of the washing liquid reached 7. Water droplets on the film surface were then gently wiped off with a cloth, completing a film immersed in a sodium hydroxide aqueous solution.

[0075] Tg-Ms Measurement The film immersed in a sodium hydroxide aqueous solution was heated from 50°C to 500°C at a heating rate of 10°C / min in a He atmosphere (flow rate 70 mL / min). ２ O gas may have a peak at a position between 300 and 500° C. The amount of water of crystallization calculated from the peak at a position between 300 and 500° C. was 3.25 wt %.

[0076] IC Measurement: 20 mL of pure water was added to 0.01 g of film immersed in a sodium hydroxide aqueous solution, and the mixture was shaken for 60 minutes at 50 to 250 r / min using a powerful shaker (Reciprocating Shaker SR-2) manufactured by Taitec, followed by 10 minutes of centrifugation at 2500 rpm. The mixture was then filtered once using a filter (Advantec, DISMIC13HP, model number: 13HP020CN). The concentration of each halogen (Cl, Br, F, I, At) in the solution (filtrate) containing ions extracted from the film obtained by filtration was measured using ion chromatography (IC). The result was that the aqueous solution concentration of each halogen was 0.033 wt%.

[0077] Raman spectroscopy measurement: Measurement was performed using a Raman spectrometer (manufactured by HORIBA, product number: LABRAM HR EV0) using a laser beam with a wavelength of 532 nm as an excitation light source to obtain the Raman spectrum of the film immersed in an aqueous sodium hydroxide solution. In the Raman spectrum, the Raman shifts were 202, 290, 453, 677, and 922 cm －１ It is thought that the compound has a lepidocrocite-type crystal structure because it had a peak at the position of 665 to 745 cm －１ and a peak at 735 to 745 cm －１ The strength is 745 to 765 cm －１ Since the strength of the TiCO3 solution is greater than that of the TiCO3 solution, it is believed that the TMA cations and TMAH used in preparing the TiCO3-containing slurry were removed and replaced with sodium cations and sodium.

[0078] (Raman Spectroscopic Measurement After Laser Irradiation) The Raman spectrum of the sodium hydroxide aqueous solution immersed film was obtained after laser irradiation with the laser intensity changed from 0.275 mW to 27.500 mW. The results are shown in Figure 8. As shown in Figure 8, the film according to this embodiment did not show much change in the Raman spectrum even when the laser intensity was increased. This indicates that the crystalline structure of the TiCO film according to this embodiment is maintained and is highly stable against strong laser light.

[0079] (Raman Spectrum Measurement After Heating) The film immersed in the aqueous sodium hydroxide solution was heated to 500° C., and then the Raman spectrum of the film was obtained. The results are shown in FIG. 9. In FIG. 9, the horizontal axis represents "Raman shift (cm －１ ) and the vertical axis is "Intensity (a.u.)" (the same applies to FIGS. 10 and 11 below). As shown in FIG. 9, the Raman spectrum of the film according to this embodiment was not significantly different from that at room temperature (RT) even after heating at 500°C. This indicates that the crystalline structure of the TiCO film according to this embodiment is maintained and that it is highly stable at high temperatures.

[0080] Example 2 First, in the same manner as in Example 1, a film immersed in an aqueous lithium chloride solution was prepared.

[0081] Preparation of a film immersed in a potassium hydroxide (KOH) aqueous solution: A 1M potassium hydroxide aqueous solution was placed in a petri dish, and the above-mentioned film immersed in a lithium chloride aqueous solution was immersed in it for 10 minutes. The film was then removed from the potassium hydroxide aqueous solution, and the film surface was rinsed with pure water to remove excess potassium hydroxide from the film surface. Washing was repeated until the pH of the washing liquid reached 7. Water droplets on the film surface were then gently wiped off with a rag, completing a film immersed in a potassium hydroxide aqueous solution.

[0082] Measurement of Tg-Ms The film immersed in an aqueous potassium hydroxide solution was heated from 50°C to 500°C at a rate of 10°C / min in a He atmosphere (flow rate 70 mL / min). ２ O gas may have a peak at a temperature between 300 and 500°C. In Example 2, H gas exists at a temperature between 300 and 500°C. ２ No O gas peak was observed.

[0083] - IC measurement 20 mL of pure water was added to 0.01 g of film immersed in an aqueous potassium hydroxide solution, and the mixture was shaken for 60 minutes at 50 to 250 r / min using a powerful shaker (Reciprocating Shaker SR-2) manufactured by Taitec, followed by 10 minutes of centrifugation at 2500 rpm, and then filtered once using a filter (DISMIC13HP, model number: 13HP020CN (Advantec)). The filtered solution (filtrate) was subjected to measurement of each halogen (Cl, Br, F, I, At) using ion chromatography (IC). The analytical result showed that the aqueous solution concentration of each halogen was 0.171 wt%.

[0084] Raman spectroscopy measurement: Measurement was performed using a Raman spectrometer (manufactured by HORIBA, product number: LABRAM HR EV0) using a laser beam with a wavelength of 532 nm as an excitation light source to obtain the Raman spectrum of the film immersed in an aqueous potassium hydroxide solution. In the Raman spectrum, the Raman shifts were 202, 290, 453, 677, and 922 cm －１ It is thought that the compound has a lepidocrocite-type crystal structure because it had a peak at the position of 665 to 745 cm －１ and a peak at 735 to 745 cm －１ The strength is 745 to 765 cm －１ Since the strength of the TiCO3 solution is greater than that of the TiCO3 solution, it is believed that the TMA cations and TMAH used in preparing the TiCO3-containing slurry were removed and replaced with potassium cations and potassium.

[0085] (Raman Spectroscopic Measurement After Laser Irradiation) The film immersed in a potassium hydroxide aqueous solution was irradiated with a laser at a laser intensity varying from 0.275 mW to 27.500 mW, and then the Raman spectrum of the film immersed in a potassium hydroxide aqueous solution was obtained. As a result, similar to FIG. 8 in Example 1, the film according to this embodiment showed little change in the Raman spectrum even when the laser intensity was increased. This indicates that the crystalline structure of the TiCO film is maintained and that it is highly stable against strong laser light.

[0086] (Raman Spectroscopic Measurement After Heating) The Raman spectrum of the film immersed in an aqueous potassium hydroxide solution was obtained after heating to 500°C. The results are shown in Figure 10. As shown in Figure 10, the Raman spectrum of the film according to this embodiment did not change significantly even when the laser intensity was increased. This indicates that the crystalline structure of the TiCO film is maintained and that it has high stability against high temperatures.

[0087] Example 3 Ion Conduction Properties Using the film (before heating) immersed in the potassium hydroxide aqueous solution prepared in Example 1, ion conduction in the thickness direction was measured as follows, assuming a solid electrolyte sample.

[0088] A pair of electrodes was placed on a surface perpendicular to the thickness direction of the film (solid electrolyte sample). A DC or AC voltage was applied between the sample and the pair of electrodes, and the ionic current flowing within the sample was measured. The resistance (impedance) generated within the sample was determined from the relationship between the measured ionic current and the applied voltage. The ionic conductivity generated within the sample was calculated from the thickness and area of ​​the sample and the determined resistance (impedance). Specifically, a cylindrical sample with a diameter of 10 mm and a thickness of 100 μm was prepared as the solid electrolyte sample. A pair of metallic disk-shaped electrodes (10 mm in diameter) was placed on both end faces of the sample and brought into close contact with the sample surface. An AC signal (amplitude 10 mV) with an AC frequency ranging from 20 Hz to 50 MHz was applied between the pair of electrodes. The AC response signal (impedance) flowing between the pair of electrodes was then measured using an impedance analyzer.

[0089] The resistance component (R) was determined from the measured impedance data by equivalent circuit analysis.

[0090] Sample thickness (d = 100 μm), sample cross-sectional area (A = 78.5 mm ２The ionic conductivity (σ) was calculated from the obtained resistance component (R) using equation (4) and was found to be 1.1 mS / cm. When the ionic conductivity (σ) was 0.001 mS or more at 30°C and 95% RH, it was confirmed that a suitable solid electrolyte material was obtained, which is useful as a solid electrolyte for fuel cells and water electrolysis. σ = (1 / R) * (A / d) (4)

[0091] The solid electrolyte of a fuel cell is expected to be operated, for example, at 80 to 100°C for 2000 hours or more. For example, if MQO is used as the solid electrolyte or as an additive and operated at the aforementioned temperature and for the aforementioned time, it is conceivable that the MQO may undergo a phase transition. For this reason, as evaluated in Example 1, it is preferable to use the MQO according to this embodiment, which has a stable crystal structure.

[0092] Comparative Example 1 First, a film (free-standing film) was obtained in the same manner as in Example 1.

[0093] - Preparation of a film immersed in an aqueous lithium chloride (LiCl) solution To achieve the same number of immersions as in Examples 1 and 2, the film (freestanding film) was immersed in a 1 M aqueous lithium chloride solution in a petri dish for 10 minutes, and then the petri dish was again filled with a 1 M aqueous lithium chloride solution, and the film (freestanding film) was immersed in the same for 10 minutes. The film was then removed from the aqueous lithium chloride solution, and the film surface was rinsed with pure water to remove excess lithium chloride from the film surface. Washing was repeated until the pH of the rinse solution reached 7. Water droplets on the film surface were then gently wiped off with a rag, completing a film immersed in an aqueous lithium chloride solution.

[0094] Tg-Ms Measurement The film immersed in a lithium chloride aqueous solution was heated from 50°C to 500°C at a heating rate of 10°C / min in a He atmosphere (flow rate 70 mL / min). ２ The amount of water of crystallization calculated from the O gas peak was 2.75 wt %.

[0095] IC Measurement 20 mL of pure water was added to 0.01 g of film immersed in a lithium chloride aqueous solution, and the mixture was shaken for 60 minutes at 50 to 250 r / min using a powerful shaker (Reciprocating Shaker SR-2) manufactured by Taitec, followed by 10 minutes of centrifugation at 2500 rpm. The mixture was then filtered once using a filter (DISMIC13HP, model number: 13HP020CN, manufactured by Advantec). The concentrations of each halogen (Cl, Br, F, I, At) in the filtered solution (filtrate) were measured using ion chromatography (IC). The results showed that the aqueous solution concentration of each halogen was 1.1 wt%.

[0096] Raman spectroscopy analysis: The Raman spectrum of the film immersed in a lithium chloride aqueous solution was obtained under the same conditions as in Example 1. As a result, similar to Example 1, the Raman spectrum showed Raman shifts of 198, 286, 453, 684, and 956 cm －１ From this, it is considered that the film produced in Comparative Example 1 also has a lepidocrocite-type crystal structure. －１ and a peak at 735 to 745 cm －１ The strength is 745 to 765 cm －１ Since this is larger, it is believed that the TMA cations and TMAH used in preparing the slurry containing TiCO have been removed and replaced with lithium cations and lithium.

[0097] (Raman Spectrum Measurement After Laser Irradiation) As in Example 1, the film immersed in a lithium chloride aqueous solution was irradiated with a laser at a laser intensity varying from 0.275 mW to 27.500 mW, and the Raman spectrum of the film immersed in a lithium chloride aqueous solution after laser irradiation at each laser intensity was obtained. As a result, when the laser intensity was increased, the Raman spectrum changed at 6.875 mW, indicating that the crystal structure had changed. In particular, the Raman shifts in the Raman spectrum were 153, 205, 395, 521, and 638 cm －１From this, it is estimated that the crystal structure was transformed from lepidocrocite to anatase when the laser intensity was increased to 6.875 mW or more.

[0098] (Raman Spectrum Measurement After Heating) The Raman spectrum of the film immersed in an aqueous lithium chloride solution was obtained after heating to 500° C. The results are shown in Fig. 11. As can be seen from Fig. 11, the film of Comparative Example 1 showed a large change in the Raman spectrum when the laser intensity was increased, indicating that the film had low stability against high temperatures.

[0099] When the amount of halogen contained in an oxide material is high, it is thought that the material may exhibit instability, in that its crystal structure may change due to physical stimuli such as laser light or heat, and the functions it exhibits may change, making it impossible for the oxide material to stably exhibit its properties.

[0100] Comparative Example 2 First, a film immersed in an aqueous lithium chloride solution was prepared in the same manner as in Example 1.

[0101] Calcium chloride (CaCl ２ ) Preparation of aqueous solution-immersed film A 1 M aqueous calcium chloride solution was placed in a petri dish, and the film immersed in the aqueous lithium chloride solution was immersed in it for 10 minutes. The film was then removed from the aqueous calcium chloride solution, and the film surface was rinsed with pure water to remove excess calcium chloride from the film surface. Washing was repeated until the pH of the washing liquid reached 7. Water droplets on the film surface were then gently wiped off with a rag, completing the calcium chloride aqueous solution-immersed film.

[0102] Measurement of Tg-Ms The film immersed in a calcium chloride aqueous solution was heated from 50°C to 500°C at a rate of 10°C / min in a He atmosphere (flow rate 70 mL / min). ２ The amount of water of crystallization calculated from the O gas peak was 4.36 wt %.

[0103] IC Measurement: 20 mL of pure water was added to 0.01 g of film immersed in a calcium chloride aqueous solution, and the mixture was shaken for 60 minutes at 50 to 250 r / min using a powerful shaker (Reciprocating Shaker SR-2) manufactured by Taitec, followed by 10 minutes of centrifugation at 2500 rpm. The mixture was then filtered once using a filter (Advantec, DISMIC13HP, model number: 13HP020CN). The concentrations of each halogen (Cl, Br, F, I, At) in the filtered solution (filtrate) were measured using ion chromatography (IC). The results showed that the aqueous solution concentration of each halogen was 1.03 wt%.

[0104] Raman spectroscopy measurement The Raman spectrum of the film immersed in a calcium chloride aqueous solution was obtained under the same conditions as in Example 1. As a result, similar to Example 1, the Raman spectrum showed Raman shifts of 198, 286, 453, 684, and 956 cm －１ From this, it is considered that the film produced in Comparative Example 2 also has a lepidocrocite-type crystal structure. －１ and a peak at 735 to 745 cm －１ The strength is 745 to 765 cm －１ Since this is larger, it is believed that the TMA cations and TMAH used in preparing the TiCO-containing slurry were removed and replaced with calcium cations and calcium.

[0105] (Raman Spectrum Measurement After Laser Irradiation) As in Example 1, the film immersed in a calcium chloride aqueous solution was irradiated with a laser at a laser intensity varying from 0.275 mW to 27.500 mW, and the Raman spectrum of the film immersed in a calcium chloride aqueous solution after laser irradiation at each laser intensity was obtained. As a result, when the laser intensity was increased to 6.875 mW, the Raman spectrum changed, indicating that the crystal structure had changed. In the Raman spectrum, the Raman shifts were 153, 205, 395, 521, and 638 cm －１ Since the peak was at the position of , it is considered that the crystal structure has an anatase type crystal structure after the change in crystal structure.

[0106] From this, it is estimated that the crystal structure transitioned from lepidocrocite to anatase when the laser was irradiated at an intensity of 6.875 mW or more. When the amount of halogen contained in an oxide material is high, the crystal structure is unstable and changes when exposed to physical stimuli such as laser light or heat, which may change the functions that are expressed, making it impossible to stably demonstrate the properties of the oxide material.

[0107] Comparative Example 3 First, in the same manner as in Example 1, a film immersed in an aqueous lithium chloride solution was prepared.

[0108] Magnesium chloride (MgCl ２ ) Preparation of film immersed in aqueous solution A 1 M magnesium chloride aqueous solution was placed in a petri dish, and the film immersed in the lithium chloride aqueous solution was immersed in it for 10 minutes. The film was then removed from the magnesium chloride aqueous solution, and the film surface was rinsed with pure water to remove excess magnesium chloride from the film surface. Washing was repeated until the pH of the washing liquid reached 7. Water droplets on the film surface were then gently wiped off with a rag, completing the magnesium chloride aqueous solution immersed film.

[0109] Measurement of Tg-Ms The film immersed in an aqueous magnesium chloride solution was heated from 50°C to 500°C at a rate of 10°C / min in a He atmosphere (flow rate 70 mL / min). ２ The amount of water of crystallization calculated from the O gas peak was 4.81 wt %.

[0110] IC Measurement: 20 mL of pure water was added to 0.01 g of film immersed in an aqueous magnesium chloride solution, and the mixture was shaken for 60 minutes at 50 to 250 r / min using a powerful shaker (Reciprocating Shaker SR-2) manufactured by Taitec. Then, the mixture was centrifuged at 2500 rpm for 10 minutes, and then filtered once using a filter (DISMIC13HP, model number: 13HP020CN, manufactured by Advantec). The concentrations of each halogen (Cl, Br, F, I, At) in the filtered solution (filtrate) were measured using ion chromatography (IC). The results showed that the aqueous solution concentration of each halogen was 1.03 wt%.

[0111] Raman spectroscopy measurement The Raman spectrum of the film immersed in an aqueous magnesium chloride solution was obtained under the same conditions as in Example 1. As a result, similar to Example 1, the Raman spectrum showed Raman shifts of 198, 286, 453, 684, and 956 cm －１ From this, it is considered that the film produced in Comparative Example 3 also has a lepidocrocite-type crystal structure. －１ and a peak at 735 to 745 cm －１ The strength is 745 to 765 cm －１ Since this is larger, it is believed that the TMA cations and TMAH used in preparing the slurry containing TiCO were removed and replaced with magnesium cations and magnesium.

[0112] (Raman Spectrum Measurement After Laser Irradiation) As in Example 1, the magnesium chloride aqueous solution immersed film was irradiated with laser at laser intensities varying from 0.275 mW to 27.500 mW, and the Raman spectrum of the lithium chloride aqueous solution immersed film after laser irradiation at each laser intensity was obtained. As a result, when the laser intensity was increased to 6.875 mW, the Raman spectrum changed, indicating that the crystal structure had changed. In the Raman spectrum, the Raman shifts were 153, 205, 395, 521, and 638 cm －１ Since the peak was at the position of , it is considered that the crystal structure has an anatase type crystal structure after the change in crystal structure.

[0113] From this, it is estimated that the crystal structure transitioned from lepidocrocite to anatase when the laser was irradiated at an intensity of 6.875 mW or more. When the amount of halogen contained in an oxide material is high, the crystal structure is unstable and changes when exposed to physical stimuli such as laser light or heat, which may change the functions that are expressed, making it impossible to stably demonstrate the properties of the oxide material.

[0114] Comparative Example 4 First, in the same manner as in Example 1, a film immersed in an aqueous lithium chloride solution was prepared.

[0115] Preparation of a film immersed in a potassium chloride (KCl) aqueous solution A 1 M potassium chloride aqueous solution was placed in a petri dish, and the film immersed in a lithium chloride aqueous solution was immersed in it for 10 minutes. The film was then removed from the potassium chloride aqueous solution, and the film surface was rinsed with pure water to remove excess potassium chloride from the film surface. Washing was repeated until the pH of the washing liquid reached 7. Water droplets on the film surface were then gently wiped off with a rag, completing a film immersed in a potassium chloride aqueous solution.

[0116] Measurement of Tg-Ms The film immersed in an aqueous potassium chloride solution was heated from 50°C to 500°C at a rate of 10°C / min in a He atmosphere (flow rate 70 mL / min). ２ No O gas peak was detected.

[0117] IC Measurement: 20 mL of pure water was added to 0.01 g of film immersed in a potassium chloride aqueous solution, and the mixture was shaken for 60 minutes at 50 to 250 r / min using a powerful shaker (Reciprocating Shaker SR-2) manufactured by Taitec. Then, the mixture was centrifuged at 2500 rpm for 10 minutes, and then filtered once using a filter (DISMIC13HP, model number: 13HP020CN, manufactured by Advantec). The concentrations of each halogen (Cl, Br, F, I, At) in the filtered solution (filtrate) were measured using ion chromatography (IC). The results showed that the aqueous solution concentration of each halogen was 1.3 wt%.

[0118] Raman spectroscopy analysis measurement A Raman spectrum was obtained under the same conditions as in Example 1. As a result, similar to Example 1, the Raman spectrum showed Raman shifts of 198, 286, 453, 684, and 956 cm －１ From this, it is considered that the film produced in Comparative Example 4 also has a lepidocrocite-type crystal structure. －１ and a peak at 735 to 745 cm －１ The strength is 745 to 765 cm －１ Since this is larger, it is believed that the TMA cations and TMAH used in preparing the TiCO-containing slurry have been removed and replaced with potassium cations and potassium.

[0119] (Raman Spectrum Measurement After Laser Irradiation) As in Example 1, the potassium chloride aqueous solution immersed film was irradiated with laser at laser intensities varying from 0.275 mW to 27.500 mW, and the Raman spectrum of the lithium chloride aqueous solution immersed film after laser irradiation at each laser intensity was obtained. As a result, when the laser intensity was increased to 6.875 mW, the Raman spectrum changed, indicating that the crystal structure had changed. In the Raman spectrum, the Raman shifts were 153, 205, 395, 521, and 638 cm －１ Since the peak was at the position of , it is considered that the crystal structure has an anatase type crystal structure after the change in crystal structure.

[0120] From this, it is estimated that the crystal structure transitioned from lepidocrocite to anatase when the laser was irradiated at an intensity of 6.875 mW or more. When the amount of halogen contained in an oxide material is high, the crystal structure is unstable and changes when exposed to physical stimuli such as laser light or heat, which may change the functions that are expressed, making it impossible to stably demonstrate the properties of the oxide material.

[0121] Comparative Example 5 First, in the same manner as in Example 1, a film immersed in an aqueous lithium chloride solution was prepared.

[0122] Preparation of a film immersed in a sodium chloride (NaCl) aqueous solution A 1 M sodium chloride aqueous solution was placed in a petri dish, and the film immersed in a lithium chloride aqueous solution was immersed in it for 10 minutes. The film was then removed from the sodium chloride aqueous solution, and the film surface was rinsed with pure water to remove excess sodium chloride from the film surface. Washing was repeated until the pH of the washing liquid reached 7. Water droplets on the film surface were then gently wiped off with a cloth, completing a film immersed in a sodium chloride aqueous solution.

[0123] Measurement of Tg-Ms The film immersed in an aqueous sodium chloride solution was heated from 50°C to 500°C at a rate of 10°C / min in a He atmosphere (flow rate 70 mL / min). ２ The amount of water of crystallization calculated from the O gas peak was 1.97 wt %.

[0124] IC Measurement: 20 mL of pure water was added to 0.01 g of film immersed in a sodium chloride aqueous solution, and the mixture was shaken for 60 minutes at 50 to 250 r / min using a powerful shaker (Reciprocating Shaker SR-2) manufactured by Taitec. Then, the mixture was centrifuged at 2500 rpm for 10 minutes, and then filtered once using a filter (Advantec, DISMIC13HP, model number: 13HP020CN). The concentrations of each halogen (Cl, Br, F, I, At) in the filtered solution (filtrate) were measured using ion chromatography (IC). The results showed that the aqueous solution concentration of each halogen was 0.54 wt%.

[0125] Raman spectroscopy analysis measurement A Raman spectrum was obtained under the same conditions as in Example 1. As a result, similar to Example 1, the Raman spectrum showed Raman shifts of 198, 286, 453, 684, and 956 cm －１ From this, it is considered that the film produced in Comparative Example 5 also has a lepidocrocite-type crystal structure. －１ and a peak at 735 to 745 cm －１ The strength is 745 to 765 cm －１Since the TMA cations and TMAH used in preparing the TiCO-containing slurry are larger than 0.01, it is considered that they were removed and replaced with sodium cations and sodium.

[0126] (Raman Spectrum Measurement After Laser Irradiation) As in Example 1, the sodium chloride aqueous solution immersed film was irradiated with laser at laser intensities varying from 0.275 mW to 27.500 mW, and the Raman spectrum of the lithium chloride aqueous solution immersed film after laser irradiation at each laser intensity was obtained. As a result, when the laser intensity was increased to 6.875 mW, the Raman spectrum changed, indicating that the crystal structure had changed. In the Raman spectrum, the Raman shifts were 153, 205, 395, 521, and 638 cm －１ Since the peak was at the position of , it is considered that the crystal structure has an anatase type crystal structure after the change in crystal structure.

[0127] From this, it is estimated that the crystal structure transitioned from lepidocrocite to anatase when the laser was irradiated at an intensity of 6.875 mW or more. When the amount of halogen contained in an oxide material is high, the crystal structure is unstable and changes when exposed to physical stimuli such as laser light or heat, which may change the functions that are expressed, making it impossible to stably demonstrate the properties of the oxide material.

[0128] Comparative Example 6 The TiCO film in Example 1 was prepared, and a film (free-standing film) that was not immersed in an aqueous potassium hydroxide (KOH) solution was used to perform Raman spectroscopic analysis.

[0129] Raman spectroscopy analysis measurement A Raman spectrum was obtained under the same conditions as in Example 1. As shown in FIG. 12 , the Raman spectrum showed Raman shifts of 198, 286, 453, 684, and 956 cm －１ It is thought that the compound has a lepidocrocite-type crystal structure because it had a peak at the position of 760 cm －１ The presence of a peak around this region indicated the presence of TMA cations and TMAH in the film.

[0130] When the laser intensity was increased to 6.875 mW, the Raman spectrum changed, indicating that the crystal structure had changed. In the Raman spectrum, the Raman shifts were 153, 205, 395, 521, and 638 cm －１ It is thought that the material has an anatase crystal structure, as it had a peak at this position. From the above, it was estimated that when a laser intensity of 6.875 mW or more was irradiated, the crystal structure transitioned from lepidocrocite to anatase. For example, the material is unstable in that its crystal structure changes due to physical stimuli such as laser light or heat, and it is thought that the functions it exhibits may change.

[0131] The disclosure of the present specification may include the following aspects: <1> A compound represented by the following formula: MQ ａ O ｂ (wherein M is at least one element selected from the group consisting of Groups 3, 4, 5, 6 and 7; Q is at least one element (excluding O) selected from the group consisting of Groups 12, 13, 14, 15 and 16; a is 0 or more and 2 or less; and b is 0 or more and 2 or less), and the oxide material contains potassium in surface groups and / or between layers. <2> The oxide material according to <1>, wherein M is Ti, Q is C, and a is not 0.

[0132] This application claims priority to U.S. Application No. 63 / 512,971, filed July 11, 2023, the entire contents of which are incorporated herein by reference.

[0133] The oxide materials of the present disclosure can be used in a wide variety of applications, such as photocatalysis, dye decomposition, hydrogen production, batteries, supercapacitors, gas adsorbents, urea adsorbents, and ion conductors.

Claims

1. The following formula: MQ ａ O ｂ (In the formula, M is at least one element selected from the group consisting of groups 3, 4, 5, 6 and 7, Q is at least one element selected from the group consisting of groups 12, 13, 14, 15, and 16 (excluding O), a is between 0 and 2, b is greater than 0 and less than or equal to 2. It includes one or more selected from the group consisting of nanofibers, nanowires, and two-dimensional materials, represented by The surface and / or interlayers contain metallic elements and / or metalloid elements, An oxide material having a total halogen element content of 0.90% by mass or less.

2. The oxide material according to claim 1, wherein the total content of the halogen elements is 0.50% by mass or less.

3. The oxide material according to claim 1 or 2, wherein the halogen element is one or more selected from the group consisting of Cl, Br, F, I, and At.

4. The oxide material according to claim 1 or 2, wherein the crystal structure is of the lepidocrocite type.

5. The oxide material according to claim 1 or 2, wherein the content of crystal water is 10% by mass or less.

6. The oxide material according to claim 1 or 2, wherein M is Ti, Q is C, and a is not 0.

7. The oxide material according to claim 1 or 2, wherein the metallic element and / or metalloid element is one or more selected from the group consisting of K, Na, Li, Ca, and Mg.

8. The following formula: MQ ａ O ｂ (In the formula, M is at least one element selected from the group consisting of groups 3, 4, 5, 6 and 7, Q is at least one element selected from the group consisting of groups 12, 13, 14, 15, and 16 (excluding O), a is between 0 and 2, b is greater than 0 and less than or equal to 2. It includes one or more selected from the group consisting of nanofibers, nanowires, and two-dimensional materials, represented by The surface and / or interlayers contain metallic elements and / or metalloid elements, An ionic conductor comprising an oxide material having a total halogen element content of 0.90% by mass or less, a lepidocrocite crystal structure, a crystal water content of 10% by mass or less, and the metal element and / or metalloid element being one or more selected from the group consisting of K, Na, Li, Ca, and Mg.