Radical scavenger

Abstract

This radical scavenger is formed from a material including at least one selected from the group consisting of nanofibers, nanowires, and two-dimensional materials. The material is represented by the following formula: MQaOb (where: 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 1, 2, 12, 13, 14, 15, and 16; a is at least 0 and no greater than 2; and b is greater than 0 and no greater than 2). The material contains an organic molecule and / or a metal on the surface and / or between layers, and has a carrier concentration of 1016 cm-3 to 1023 cm-3.

Description

Radical Scavenger

[0001] The present disclosure relates to radical scavengers.

[0002] Radical scavengers are widely used to control radical reactions. Controlling radical reactions with radical scavengers suppresses undesirable side reactions, allowing the desired reaction to proceed efficiently. For example, ROS (reactive oxygen species) scavenging, which scavenges radicals in the body, is useful for various healthcare applications, such as antioxidant therapy, treatment of neurodegenerative diseases, cancer treatment, prevention of cardiovascular disease, anti-aging, and immunomodulation. Because high levels of ROS damage cells, ROS scavengers are used to maintain cellular health.

[0003] Incidentally, 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 It has been shown that one-dimensional (1D) nanofilaments (NFs) based on TiO2 can be applied in fields such as photocatalysis, dye decomposition, batteries, and supercapacitors. ２ This is shown for P-25, where

[0004] Hussein O. Badr et al., "On the structure of one-dimensional TiO2 lepidocrocite" Matter 6, 128-141, January 4, 2023Teruhisa Ohno et al., "Morphology of a TiO2 Photocatalyst (Degussa, P-25) Consisting of Anatase and Rutile Crystalline Phases" Journal of Catalysis 203, 82-86, June 23, 2001

[0005] General-purpose TiO ２ Although P-25, which is represented by the formula (I), has high chemical stability, it does not act as a radical scavenger for suppressing the above-mentioned undesired reactions. The present disclosure has been made in consideration of the above circumstances, and an object of the present disclosure is to provide a novel radical scavenger that can control or suppress radical reactions.

[0006] According to one aspect of the present disclosure, there is provided 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 1, 2, 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), and the material contains 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 1, 2, 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), and the material contains organic molecules and / or metals on the surface and / or between layers, and has a carrier concentration of 10 １６ cm －３ That's it, 10 ２３ cm －３ The following radical scavengers are provided:

[0007] According to the present disclosure, a novel radical scavenger capable of controlling or suppressing radical reactions is provided.

[0008] FIG. 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 another 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 a diagram showing oxidation conditions for measuring redox capacity in the examples; FIG. 9 is a diagram showing reduction conditions for measuring redox capacity in the examples; FIG. 10 is a diagram showing the results of redox capacity measurement in the examples; FIG. 11 is a diagram showing the results of oxidizing capacity measurement in the examples; FIG. 12 is a diagram showing the results of reducing capacity measurement in the examples.

[0009] This embodiment is made of a material containing one or more selected from the group consisting of nanofibers, nanowires, and two-dimensional substances of a predetermined material, and contains organic molecules and / or metals on the surface and / or between layers, and has a carrier concentration of 10 １６ cm －３ That's it, 10 ２３ cm －３ The following relates to radical scavengers:

[0010] In the present disclosure, the mere mention of a "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 or more selected from the group consisting of nanofibers, nanowires, and two-dimensional materials). 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 material that is solid and does not contain a binder or the like (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 can 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 be unavoidably mixed in). However, materials comprising one or more selected from the group consisting of nanofibers, nanowires, and two-dimensional materials are not limited to these.

[0011] The radical scavenger is made of a material containing one or more selected from the group consisting of nanofibers, nanowires, and two-dimensional materials. In this specification, the term "consisting of" means that this embodiment includes embodiments in which, in addition to the material containing one or more selected from the group consisting of nanofibers, nanowires, and two-dimensional materials, other materials such as additives suitable for radical scavengers are included; embodiments in which the radical scavenger is essentially made of a material containing one or more selected from the group consisting of nanofibers, nanowires, and two-dimensional materials (which may include other objects or impurities that may inevitably be mixed in); and embodiments in which the radical scavenger is made only of a material containing one or more selected from the group consisting of nanofibers, nanowires, and two-dimensional materials.

[0012] The material contained in the radical scavenger 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 1, 2, 12, 13, 14, 15 and 16 (excluding O), and may include at least one element selected from the group consisting of Li, Na, K, 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.)

[0013] Hereinafter, the above-mentioned predetermined material will also be simply referred to as "MQO". Examples of MQO include those in which Q is one or more of C, K, Na, and Li, and particularly those in which Q is K. Examples of MQO include TiO ２ , TiCO, TiLiO, TiNaO, TiKO, TiCaO, TiMgO, 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.

[0014] 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. The crystal structure of MQO is preferably lepidocrocite type.

[0015] 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.

[0016] As the first raw material, a material represented by the following formula (2) can be used: M ｃ A １ ｄ ... (2) (wherein M is as defined above, A １ is at least one element selected from the group consisting of Groups 1, 2, 12, 13, 14, 15, and 16, and may include, for example, at least one element selected from the group consisting of Li, Na, K, 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°.

[0017] Examples of the first raw material represented by formula (2) include TiB ２ , TiB, TiC, TiN, TiO ２ , Ti ５ Si ３ , Ti２ 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.

[0018] 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 ２ is at least one element selected from the group consisting of Groups 1, 2, 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 ２The MAX phase has repeating units arranged in "atomic layers." However, the MAX phase is not limited to this.

[0019] 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:

[0020] 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).

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] The above reaction produces MQO, which may eventually grow into MQO nanofibers and further into 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 in FIG. 1A (width in the

[001] direction in FIG. 1A), as shown schematically in FIG. 1A. Alternatively, multiple MQO nanofibers (or nanoribbons) may overlap each other through bonding and / or intermolecular interactions (e.g., van der Waals forces), forming a laminate (layered nanofiber, layered nanoribbon) as shown schematically in FIG. 1B. Alternatively, the nanofibers may grow into nanoflakes extending two-dimensionally, as shown schematically 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 layered 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.

[0027] 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.

[0028] Washing may be carried out using a protic solvent. The same explanation as above applies to the protic solvent, and washing may be carried out using, for example, water or alcohol as the protic solvent. 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. 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 halide (fluoride, chloride, bromide, iodide) or hydroxide (OH) of an alkali metal (Li, Na, K, etc.). Representative examples include LiCl, NaCl, KCl, and LiOH. Alternatively, as in the cleaning using the aqueous solution of a metal salt, TiRO is first formed as a precursor using an aqueous solution of a metal salt of metal R, and then the TiRO is mixed with an aqueous solution of a metal salt of metal X to replace metal R with metal X, thereby obtaining the target TiXO.

[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 radical scavenger that is the material containing MQO or that contains the material can be obtained.

[0032] To obtain a material with a predetermined carrier concentration, the conditions (temperature, time, atmospheric conditions, etc.) of the oxygen defect generation process for the obtained MQO-containing material can be adjusted to control the amount and distribution of oxygen defects generated in, for example, TiCO, and thereby adjust the carrier concentration. The material obtained in this way can capture radicals and control or suppress radical reactions, and also exhibits high electrical conductivity and excellent photocatalytic activity, making it useful in a variety of applications.

[0033] TiO ２ The material is subjected to oxygen vacancies by methods such as high temperature reduction or plasma treatment. This process results in the formation of TiO ２ In the process, some oxygen atoms are removed, forming an incomplete crystal structure. This generates free electrons and increases the carrier concentration. For example, in the case of a high-temperature reduction treatment, a material containing MQO is heated to, for example, H ２and CO at a heating temperature of 100 to 800° C. Alternatively, as shown in the examples described later, a material containing MQO may be irradiated with a laser.

[0034] 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.

[0035] In the present disclosure, MQO is a solid content. MQO may typically be in the form of particles (or powder).

[0036] 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 organic molecules and / or metals may be present between these layers. For example, at least one selected from the group consisting of ammonium ions (e.g., quaternary ammonium cations) and metal cations (e.g., alkali metal ions, alkaline earth metal ions) may be present between these layers.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] Representative atomic models of the radical scavenger of this embodiment (more specifically, MQO) are shown along

[100] ,

[010] , and

[001] , for example, in Figures 2 to 4. In these figures, the number of atoms in each direction is not limited to this figure, and will be described later as a suitable range of the length in each direction.

[0043] 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.

[0044] The length in the

[010] direction can be 1 nm to 5 μm, and 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.

[0045] The length in the

[001] direction may 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.

[0046] Although not intended to limit 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 that are approximately the same (within a 20% error).

[0047] 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 2 to 5 (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.

[0048] 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.

[0049] 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.

[0050] 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).

[0051] However, it should be noted that the MQO is not limited to the above forms and may have any suitable form.

[0052] (Applications of Radical Scavengers) Radical scavengers are widely used to control radical reactions. Controlling radical reactions with radical scavengers suppresses undesirable side reactions and allows the target reaction to proceed efficiently. For example, ROS (reactive oxygen species) scavenging, which captures radicals in the body, is useful in various healthcare applications, such as antioxidant therapy, treatment of neurodegenerative diseases, cancer treatment, prevention of cardiovascular disease, anti-aging, and immunomodulation. Radical scavengers are also used in fuel cells, a technology that converts chemical energy into electrical energy using electrochemical reactions, and in water electrolysis technology, which electrochemically produces energy resources such as hydrogen. Specifically, components used in fuel cells and water electrolysis, such as electrodes and solid electrolytes, often deteriorate due to OH radicals derived from hydrogen peroxide. Adding a radical scavenger in this case can suppress this deterioration by capturing the generated radicals. Furthermore, in the present disclosure, MQO may be used not only as a radical scavenger but also as an electrode or solid electrolyte.

[0053] Materials with oxygen defects are important for adjusting electrical and optical properties. By introducing oxygen defects, radicals can be captured, and radical reactions can be controlled or suppressed. Furthermore, by introducing oxygen defects, the supply of electrons increases, improving electrical conductivity and light absorption properties. The amount of oxygen defects correlates with the carrier concentration. The carrier concentration generally refers to the number of electrons or holes that can move freely in a semiconductor material. The concentration of these electrons and holes has a significant effect on the radical scavenging properties, and the electrical and optical properties of the material. The radical scavenger of this embodiment has a carrier concentration of 10 １６ cm －３ That's it, 10 ２３ cm －３ The radical scavenger of this embodiment has a carrier concentration within the above-mentioned appropriate range, so that it can control or suppress radical reactions. From the following five viewpoints, the radical scavenger of this embodiment needs to have a carrier concentration within the above-mentioned range.

[0054] (1) Appropriate reaction rate: First, an appropriate carrier concentration is important for adjusting the rate of the radical scavenging reaction. Excessive carrier concentration can excessively increase the reaction rate, making it difficult to control. On the other hand, an appropriate range of carrier concentration can promote efficient radical scavenging reactions and achieve the formation of desired products.

[0055] (2) Maintaining charge neutrality: Within an appropriate carrier concentration range, charge neutrality is maintained throughout the material. Excessive carrier concentration can cause uneven distribution of charge, which can affect the electrical properties and stability of the material. In contrast, if the carrier concentration is within an appropriate range, charge balance is maintained throughout the material, increasing the stability of the material.

[0056] (3) Efficient radical scavenging: An appropriate carrier concentration is important for increasing the efficiency of the radical scavenger. The presence of a sufficient number of carriers promotes reaction with and diffusion of radicals. Efficient and rapid radical scavenging can achieve the desired effect.

[0057] (4) Stability and Durability Within an appropriate carrier concentration range, the stability and durability of the material are improved. An excessive carrier concentration may cause a non-uniform reaction within the material, but within an appropriate range, it is preferable because it is easier to maintain a stable and uniform state. An insufficient carrier concentration may result in an extreme increase in resistance and / or a decrease in carrier lifetime, but within an appropriate range, it is preferable because it is easier to suppress the increase in resistance and / or the decrease in carrier lifetime.

[0058] (5) Controllable reaction conditions: Within the appropriate carrier concentration range, reaction conditions and control parameters can be easily adjusted, facilitating optimization to improve product quality and reaction efficiency.

[0059] From the above, the radical scavenger of this embodiment has a carrier concentration of 10 １６ cm －３ That's it, 10 ２３ cm －３ The carrier concentration is preferably within the range of 10 １８ cm －３ That's it, 10 ２１ cm －３ The carrier concentration is evaluated by techniques such as Hall effect measurements and electrical conductivity measurements. From the data obtained from these measurements, the number of free electrons and holes in the material can be calculated.

[0060] 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.

[0061] The radical scavenger of this embodiment contains organic molecules and / or metals on the surface and / or between layers. Examples of the organic molecules include one or more of an organic compound having carbon and ammonium, and examples of the metal include one or more of the typical metal elements and transition metal elements of Groups 1 (excluding hydrogen) to 15 of the periodic table. These organic molecules and metals may exist in an ionic state on the surface and / or between layers.

[0062] At this time, electrons are injected into MQO from organic molecules and / or metals present on the surface and / or between layers, which may stabilize defects such as oxygen and improve the stability of the crystal structure. Furthermore, the organic molecules and / or metals present on the surface and / or between layers may enhance the radical scavenging function. For example, ions such as Ce, Nb, Mn, and V can capture radicals by changing their oxidation number, thereby changing the radicals to a more stable state. Therefore, it is preferable that any of Ce, Nb, Mn, and V ions is further contained between layers as a radical scavenger. Here, examples of radical scavengers include oxides of Ce, Nb, Mn, and V, carbon-based materials such as graphene and carbon dots, and Ti. ３ C ２ , nitrogen-doped Ti ３ C ２ At least one selected from the group consisting of MXene, vitamin C, vitamin E, glutathione, and other antioxidant organic substances, and enzymes such as catalase, superoxide dismutase, and peroxidase may also be present.

[0063] A material containing MQO may typically have a peak in the diffraction angle 2θ range of 2° to 12° in its X-ray diffraction (XRD) pattern. While the present disclosure is not bound by any theory, the presence of a peak in the 2θ range of 2° to 12° in its XRD pattern is believed to indicate that the MQO has a crystal structure different from that of 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 a lepidocrocite crystal structure. Furthermore, the size of the d-spacing obtained from the peaks in the 2θ range of 2° to 12° can be used to supplement the identification of the interlayer ionic species. The XRD pattern and the Raman spectrum, described below, are maintained even when the material containing MQO is subjected to high-temperature reduction treatment or the like to ensure a predetermined carrier concentration.

[0064] 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.

[0065] Although this embodiment is not limited thereto, for example, the radical scavenger 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

[0066] Although this embodiment is not limited to this embodiment, for example, the radical scavenger 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.

[0067] Although this embodiment is not limited thereto, for example, the radical scavenger 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.

[0068] Although this embodiment is not limited thereto, for example, the radical scavenger 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 －１and when the intensities of the respective peaks are X, Y, and Z, X is the largest.

[0069] Although this embodiment is not limited thereto, more preferably, the radical scavenger 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] [Sample Preparation] (Example 1) Preparation of a slurry containing TiCO First, titanium diboride (TiB ２ 1 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.

[0075] - Preparation of TiCO Film Using the above-mentioned slurry containing TiCO, a TiCO film was prepared as follows. The above-mentioned slurry containing TiCO (4 mass%) was applied to a glass substrate under the following film formation conditions to obtain a precursor film. The obtained precursor film was dried overnight in an oven (50°C / normal pressure) to obtain a TiCO film. Note that the obtained TiCO film is thought to contain tetramethylammonium ions on the surface and / or between the TiCO layers, originating from the TMAH used in the production of the film. (Film formation conditions) Atomization pressure: 0.5 MPa Liquid delivery rate: 5.0 mL / min Nozzle movement rate: 15 cm / s Substrate-nozzle distance: 15 cm Number of applications: 30 Blower drying: Once per application Substrate temperature: 45°C

[0076] Preparation of oxygen-deficient TiCO (oxygen-deficient TiCO-1) The TiCO film was heated in a reducing atmosphere of H ２ The sample was fired at 200° C. for 3 hours in a gas atmosphere to prepare a TICO sample having oxygen defects (oxygen-deficient TiCO-1).

[0077] Example 2 A TiCO film was prepared in the same manner as in Example 1.

[0078] Preparation of oxygen-deficient TiCO (oxygen-deficient TiCO-2) The TiCO film was irradiated with a YVO4 third-harmonic pulse laser (wavelength 355 nm) at a laser output of 0.25 W to prepare a sample of TiCO having oxygen defects (oxygen-deficient TiCO-2).

[0079] Comparative Example 1 As a sample of Comparative Example 1, conventional titanium dioxide, AEROXIDE (registered trademark) TiO ２ P-25 was prepared.

[0080] [Hall Effect Measurement] The Hall effect of the samples of Examples 1 and 2 and Comparative Example 1 was measured as follows. Specifically, a 0.5 cm square sample was used and measured with a Hall effect measuring device (Resitest 8400, manufactured by Toyo Corporation). As a result, in Example 1, the carrier concentration was 10 １９ cm －３ In Example 2, the carrier concentration is 10 ２０cm －３ In both Examples 1 and 2, TiCO having a predetermined carrier concentration was obtained. In contrast, the sample of Comparative Example 1 had a carrier concentration of 10 １０ cm －３ Therefore, a material having a desired carrier concentration could not be obtained.

[0081] [Measurement of oxidation-reduction ability] The TiCO slurry obtained in the same manner as in Example 1 was used for this measurement. In this measurement, TiCO is referred to as "TMA".

[0082] Furthermore, slurries containing TiLiO, TiKO, or TiNaO were prepared as follows.

[0083] A slurry containing TiLiO was prepared as follows: 1. To the TiCO slurry obtained in 1-1 above, an equal volume of 1M LiCl aqueous solution was added, and the mixture was shaken for 5 minutes. 2. The reaction mixture in the container was then transferred to a centrifuge tube. Centrifugation was performed at 3500 G for 5 minutes using a centrifuge to precipitate the solids. (i) After centrifugation, the supernatant was discarded. (ii) To the remaining sediment in the centrifuge tube, an equal volume of 1M LiCl aqueous solution was added again, and the mixture was shaken for 5 minutes. (iii) Centrifugation was performed under the same conditions as above. These steps (i) to (iii) were repeated twice in total. 3. After the second centrifugation, the supernatant was removed. (i) 35 mL of pure water was added to the remaining sediment in the centrifuge tube. (ii) The mixture was then shaken for 5 minutes, and then shaken for 10 minutes using an automatic shaker. This was followed by centrifugation until the pH reached 7. After confirming that the pH had reached 7, 35 mL of pure water was added to the residue after centrifugation. The mixture to which 35 mL of pure water had been added in the procedure of 4.3 was recovered as a TiLiO slurry.

[0084] Slurries containing TiKO or TiNaO were prepared as follows: 1. To the TiCO slurry obtained in 1-1 above, equal volumes of 1M aqueous KCl or NaCl solution and 1M aqueous KH or NaOH solution were added, followed by handshaking for 5 minutes. 2. The reaction mixture in the container was then transferred to a centrifuge tube. Centrifugation was performed at 3,500 G for 5 minutes to settle the solids. (i) After centrifugation, the supernatant was discarded. (ii) The same volume of 1M aqueous KCl or NaCl solution was added to the remaining sediment in the centrifuge tube, followed by handshaking for 5 minutes. (iii) Centrifugation was performed under the same conditions as above. These steps (i) to (iii) were repeated twice. 3. After the second centrifugation, the supernatant was removed. (i) 35 mL of pure water was added to the remaining sediment in the centrifuge tube. (ii) Next, the mixture was hand-shaken for 5 minutes and then shaken for 10 minutes using an automatic shaker. This was followed by centrifugation until the pH reached 7. After confirming that the pH had reached 7, 35 mL of pure water was added to the residue after centrifugation. The mixtures to which 35 mL of pure water had been added in step 4.3 were recovered as slurries containing TiKO or TiNaO, respectively.

[0085] Measurements were performed using a PBS solution. The effects of PBS were subtracted from the actual measured results. Measurements were performed using chronoamperometry (CA), and specific voltage waveforms were applied as shown in Figure 6 for oxidation and Figure 7 for reduction, as shown in the following formula, and the current response at the electrode was recorded. The results for the total amount of oxidation and reduction are shown in Figure 8. Reduction: H ２ O ２ +2H ＋ +2e － ⇔H ２ O Oxidation: H ２ O ２ ⇔2 hours ＋ +O ２ +2e － Oxidation-reduction: 2H ２ O ２ ⇔2 hours ２ O+O ２

[0086] From Fig. 8, it was confirmed that in all the examples the voltage was not near zero and radical scavenging was successful. In addition, the results of the total amount of oxidation and reduction in Fig. 8 were separated into oxidation and reduction, and the results of oxidation only are shown in Fig. 9, and the results of reduction only are shown in Fig. 10. In Figs. 9 and 10, the horizontal axis indicates the number of cycles, with one cycle lasting 15 seconds. From Figs. 9 and 10, it can be seen that both oxidation and reduction reactions were occurring stably. This also shows that in all the examples investigated, H ２ O ２ In particular, even when a voltage cycle for redox was repeatedly applied, the ΔJ value either continuously increased or remained stable, confirming that the material of the present disclosure can repeatedly and sustainably carry out the reaction.

[0087] Based on these results, it is believed that the materials of the present disclosure, particularly TiCO, are easily absorbed by hydrogen peroxide and are easily absorbed by H ２ O ２ It was found that the material of the present disclosure contributes sufficiently to the oxidation-reduction reaction of hydrogen peroxide. Furthermore, even when a voltage cycle for oxidation-reduction is repeatedly applied, the ΔJ value either increases continuously or remains stable, which indicates that the reaction using the material of the present disclosure can be repeatedly and sustainably carried out. Furthermore, since hydrogen peroxide is a typical reactive oxygen species (ROS), the material of the present disclosure can also be used as a ROS scavenger, and can also be used as an electrochemical H ２ O ２ This makes it a promising candidate material for sensors.

[0088] 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 selected from the group consisting of Groups 1, 2, 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), and the material contains 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 1, 2, 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), and the material contains organic molecules and / or metals on the surface and / or between layers, and has a carrier concentration of 10 １６cm －３ That's it, 10 ２３ cm －３ <2> The radical scavenger according to <1>, wherein the crystal structure of the material is lepidocrocite. <3> The radical scavenger according to <1> or <2>, wherein Q in the material is K. <4> The radical scavenger according to any one of <1> to <3>, wherein the material is one or more of TiCO, TiLiO, TiKO, and TiNaO.

[0089] This application claims priority from Japanese Patent Application No. 2024-111923, which is incorporated herein by reference.

[0090] The radical scavenger of the present disclosure can be used in a wide variety of applications, such as photocatalysis, dye decomposition, hydrogen production, batteries, and supercapacitors. It can also be used as a ROS (reactive oxygen species) scavenger in various healthcare applications, such as antioxidant therapy, neurodegenerative disease treatment, cancer treatment, cardiovascular disease prevention, anti-aging, and immunomodulation. It can also be used as a radical scavenger, possibly also functioning as an electrode or solid electrolyte, in fuel cells, a technology that converts chemical energy into electrical energy using electrochemical reactions, and in water electrolysis technology, which electrochemically produces energy resources such as hydrogen.

Claims

1. 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 selected from the group consisting of Groups 1, 2, 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), and the material contains 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 1, 2, 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), and the material contains organic molecules and / or metals on the surface and / or between layers, and has a carrier concentration of 10 １６ cm －３ That's it, 10 ２３ cm －３ A radical scavenger, which is:

2. The radical scavenger according to claim 1, wherein the crystal structure of the material is lepidocrocite type.

3. The radical scavenger according to claim 1 or 2, wherein Q in said material is K.

4. The radical scavenger of claim 1 or 2, wherein the material is one or more of TiCO, TiLiO, TiKO, and TiNaO.

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