Nanoparticles for hydration electron generation, decomposition of halogen-containing organic materials, and photochromic materials.

Abstract

This invention provides a material that can generate hydrated electrons using a lower-energy, smaller, and less expensive light source, does not contain rare metals, is more cost-effective, more sustainable, and more versatile, and can be used for applications such as hydrated electron generation and decomposition of fluorine-containing compounds. [Solution] Particles represented by general formula (1):CdX [wherein formula (1) is an element of Group 16] are doped and / or adsorbed with a transition metal, and on the surface of the particles is general formula (2):-SR 21 -COOH[In formula (2), R 21 This represents an organic group having 1 to 20 carbon atoms. The nanoparticles include an organic ligand represented by ] and are for use in generating hydrated electrons, decomposing halogen-containing organic materials, or as photochromic materials.

Description

[Technical Field]

[0001] The present invention relates to nanoparticles for generating hydrated electrons, for decomposing halogen-containing organic materials, or for use as photochromic materials, and to dispersions containing such nanoparticles. [Background technology]

[0002] Hydrated electrons have attracted attention in recent years for their high reduction potential (-2.9V vs NHE (relative to a standard hydrogen electrode)), comparable to that of alkali metals, and their sufficient lifetime (approximately 1 μs) to initiate intermolecular reactions. They are particularly useful in various chemical reaction fields, such as the decomposition of recalcitrant halogenated substances and the fixation of nitrogen or carbon dioxide.

[0003] However, generally, generating hydrated electrons requires high-energy, large, and very expensive light sources such as femtosecond pulsed lasers and vacuum ultraviolet light irradiation devices (see Non-Patent Document 1).

[0004] Although the generation of hydrated electrons using relatively low-intensity light sources has also been reported, it involves the use of rare metals such as iridium catalysts, making it difficult to commercialize as an industrial technology considering costs and sustainability (see Non-Patent Document 2). Therefore, a method that can generate hydrated electrons using more versatile materials is desired. Such more versatile materials are preferably used for the decomposition of halogen-containing organic materials. Furthermore, such more versatile materials are preferably used in photochromic materials. Such more versatile materials are of great interest both academically and industrially. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] Chem. Rev. 2012, 112, 5553-5577. [Patent Document 1] J. Am. Chem. Soc. 2019, 141, 5, 2122-2127. [Overview of the project] [Problems that the invention aims to solve]

[0006] The present invention aims to provide a method for generating hydrated electrons using a lower-energy, smaller, and less expensive light source, and to provide a material that does not contain rare metals such as iridium, is less expensive, more sustainable (lower country risk), and more versatile. Furthermore, the present invention aims to provide a method for decomposing fluorine-containing compounds using the method for generating hydrated electrons. The present invention also aims to provide photochromic materials, including the material described above, which offers greater versatility. [Means for solving the problem]

[0007] The inventors diligently conducted research to solve the above problems and found that certain nanoparticles do not contain rare metals such as iridium, are less expensive, more sustainable (lower country risk), and more versatile. Furthermore, using these specific nanoparticles, hydrated electrons can be generated using lower energy, smaller, and cheaper light sources, thus solving the above problems. Based on this finding, the inventors conducted further research and completed the present invention. They also found that these specific nanoparticles can be used as photochromic materials, demonstrating their versatility.

[0008] This specification includes the following embodiments. 1. The following general formula (1) CdX (1) [In formula (1), X represents a Group 16 element.] Particles represented by are doped and / or adsorbed with transition metals, On the surface of the particle, the following general formula (2) -SR21 -COOR 22 (2) [In formula (2), R 21 represents an organic group having 1 to 20 carbon atoms which may be substituted with NH2 or OH, and R 22 represents H or an organic group having 1 to 6 carbon atoms.] Nanoparticles for generating hydrated electrons, decomposing halogen-containing organic materials, or for photochromic materials, containing particles and having an organic ligand represented by 2. The following general formula (1’) CdX (1’) [In formula (1’), X represents a Group 16 element.] Transition metal is doped and / or adsorbed on the particles represented by and on the surface of the particles, the following general formula (2’) -S-R 21 -COOR 22 (2’) [In formula (2’), R 21 represents an organic group having 3 to 20 carbon atoms which may be substituted with NH2 or OH, R 22 represents H, or R 21 represents an organic group having 1 to 20 carbon atoms which may be substituted with NH2 or OH, and R 22 represents an organic group having 1 to 6 carbon atoms.] Nanoparticles containing particles and having an organic ligand represented by 3. R 21 represents an organic group having 1 to 6 carbon atoms, and R 22 represents H, the nanoparticles according to 1 above. 4. The nanoparticles according to any one of 1 to 3 above, wherein the X is at least one selected from O, S, Se or Te. 5. The nanoparticles according to any one of 1 to 4 above, having an average particle diameter of 1 nm or more and 100 nm or less. 6. The nanoparticles according to any one of 1 to 5 above, wherein the doping rate of the transition metal with respect to Cd in the formula (1) is 0.01 to 10.0 mol%. 7. A nanoparticle aqueous dispersion in which the nanoparticles according to any one of 1 to 6 above are dispersed in water. 8. Nanoparticles according to any one of the above 2 and 4-6 referenced in 2, for use in generating hydrated electrons, decomposing halogen-containing organic materials, or as photochromic materials. 9. A method for generating hydrated electrons using nanoparticles for generating hydrated electrons described in any one of the above 1, 3 to 6, and 8, which reference 1. 10. The method for generating hydrated electrons according to item 9 above, comprising irradiating a nanoparticle for generating hydrated electrons described in any one of items 3 to 6 and 8, which references item 1 above, with visible light or ultraviolet light. 11. A method for decomposing halogen-containing organic materials, using halogen-containing organic material decomposition nanoparticles described in any one of 1, 3 to 6, and 8 above, which references 1. 12. A method for decomposing halogen-containing organic materials, comprising irradiating a halogen-containing organic material decomposition nanoparticle described in any one of 1, 3 to 6, and 8 above (referencing 1) with visible light or ultraviolet light to break the halogen-carbon bond in the halogen-containing organic material. [Effects of the Invention]

[0009] Using the nanoparticles of the embodiments of the present invention, hydrated electrons can be generated using a light source that is lower in energy, smaller in size, and less expensive. These nanoparticles do not contain rare metals such as iridium, are less costly, more sustainable (lower country risk), and more versatile. Furthermore, using the nanoparticles of the embodiments of the present invention, a method for decomposing fluorine-containing compounds can be provided, as can photochromic materials. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 shows the ultraviolet-visible absorption spectrum of the MPA-coordinated Cu-doped CdS nanocrystal of Example 1. [Figure 2] Figure 2 shows the FTIR absorption spectrum of the MPA-coordinated Cu-doped CdS nanocrystal from Example 1. [Figure 3] Figure 3 shows the XRD spectrum of the MPA-coordinated Cu-doped CdS nanocrystal from Example 1. [Figure 4]Figure 4 shows the 19F NMR measurement results of the MPA-coordinated Cu-doped CdS nanocrystal + PFOS from Example 1 before and after visible light irradiation. [Figure 5] Figure 5 shows the 19F NMR measurement results of the MPA-coordinated Cu-doped CdS nanocrystal + PFOS from Example 1 before and after visible light irradiation. [Figure 6] Figure 6 shows the 19F NMR measurement results of the MPA-coordinated Cu-doped CdS nanocrystal + PTFE from Example 1 before and after visible light irradiation. [Figure 7] Figure 7 shows the ultraviolet-visible absorption spectrum of the MPA-coordinated CdS nanocrystal of Comparative Example 1. [Figure 8] Figure 8 shows the FTIR absorption spectrum of the MPA-coordinated CdS nanocrystal of Comparative Example 1. [Figure 9] Figure 9 shows the XRD spectrum of the MPA-coordinated CdS nanocrystal of Comparative Example 1. [Figure 10] Figure 10 shows the 19F NMR measurement results of the MPA-coordinated CdS nanocrystal + POFS of Comparative Example 1 before and after visible light irradiation. [Figure 11] Figure 11 shows the FTIR absorption spectrum of the Cu-doped CdS nanocrystal of Comparative Example 2. [Figure 12] Figure 12 shows the XRD spectrum of the Cu-doped CdS nanocrystal of Comparative Example 2. [Figure 13] Figure 10 shows the 19F NMR measurement results of Cu-doped CdS nanocrystals + PFOS from Comparative Example 2 before and after visible light irradiation. [Modes for carrying out the invention]

[0011] In one aspect, the present invention, The following general formula (1) CdX (1) [In formula (1), X represents a Group 16 element.] Particles represented by are doped and / or adsorbed with transition metals, On the surface of the particle, the following general formula (2) -SR 21 -COOR 22 (2) [In formula (2), R 21 R represents an organic group having 1 to 20 carbon atoms, which may be substituted with NH2 or OH. 22 This represents H or an organic group with 1 to 6 carbon atoms. The present invention provides nanoparticles comprising particles having an organic ligand represented by, These nanoparticles can be preferably used for hydration electron generation, decomposition of halogen-containing organic materials, or as photochromic materials.

[0012] The nanoparticles of one embodiment of the present invention are given by the following general formula (1) CdX (1) [In formula (1), X represents a Group 16 element.] As shown, transition metals are doped and / or adsorbed. In the general formula (1) above, X represents a Group 16 element. Specifically, X can be at least one selected from O, S, Se, and Te, and at least one selected from O, S, Se, and Te is preferred. O and S are more preferred because they are abundant resources on Earth and have higher chemical stability. X may be a single element or a combination of two or more elements.

[0013] The nanoparticles of the above embodiments of the present invention are doped and / or adsorbed with a transition metal. When the nanoparticles are doped with a transition metal, a portion of the Cd in the particle nucleus represented by CdX is replaced with the transition metal. When the nanoparticles have a transition metal adsorbed on them, the transition metal is adsorbed on the surface of the particle nucleus represented by CdX. The nanoparticles may be doped with a transition metal, or have a transition metal adsorbed on them, or be doped with a transition metal and / or have a transition metal adsorbed on them.

[0014] Such transition metals are not particularly limited as long as they can produce the nanoparticles targeted by the present invention, but examples include manganese, cobalt, nickel, iron, chromium, copper, aluminum, molybdenum, vanadium, titanium, zirconium, niobium, silver, bismuth, and indium. Copper and manganese are preferred as transition metals because their ionic radius is close to that of cadmium and they easily trap holes, with copper being more preferred. The transition metal may be used alone or in combination of two or more.

[0015] The doping rate of the transition metal is preferably 0.01 mol% or more, more preferably 0.1 mol% or more, even more preferably 0.5 mol% or more, and even more preferably 1.0 mol% or more, with the total number of moles of Cd element and transition metal element being 100 mol%. The doping rate of the transition metal is preferably 30.0 mol% or less, more preferably 20.0 mol% or less, and even more preferably 10.0 mol% or less, with the total number of moles of Cd element and transition metal element being 100 mol%. When the doping rate of the transition metal is within the above-mentioned numerical range, the generation of hydrated electrons and the decomposition of fluorine-containing materials can be performed more efficiently. The above doping rates can be obtained by performing X-ray fluorescence analysis on the nanoparticles.

[0016] The amount of adsorbed transition metal is preferably 0.01 mol% or more, more preferably 0.1 mol% or more, even more preferably 0.5 mol% or more, and even more preferably 1.0 mol% or more, with the total number of moles of Cd element being 100 mol%. The amount of adsorbed transition metal is preferably 30.0 mol% or less, more preferably 20.0 mol% or less, and even more preferably 15.0 mol% or less, with the total number of moles of Cd element being 100 mol%. When the amount of adsorbed transition metal falls within the above-mentioned numerical range, the generation of hydrated electrons and the decomposition of fluorine-containing materials can be performed more efficiently.

[0017] The adsorption of the transition metal is not particularly limited as long as the nanoparticles targeted by the present invention can be obtained, but it is sufficient for the transition metal to be adsorbed on the surface of the nucleus of the particles represented by CdX, and physical adsorption is preferred. The form of physical adsorption is not necessarily clear, but examples include the adsorption of the transition metal on the surface of the nucleus of the particles represented by CdX by electrical actions such as van der Waals forces.

[0018] The nanoparticles of the above embodiment of the present invention have the following general formula (2) on their surface -SR 21 -COOR 22 (2) [In formula (2), R 21 R represents an organic group having 1 to 20 carbon atoms, which may be substituted with NH2 or OH. 22 This represents H or an organic group with 1 to 6 carbon atoms. It contains particles having an organic ligand represented by .

[0019] In the above general formula (2), R 21 This represents an organic group having 1 to 20 carbon atoms, which may be substituted with NH2 or OH. The organic group having 1 to 20 carbon atoms is not limited as long as the nanoparticles targeted by the present invention can be obtained, and examples include aliphatic hydrocarbon groups, aromatic hydrocarbon groups, alicyclic hydrocarbon groups, etc. Examples of aliphatic hydrocarbon groups include linear hydrocarbon groups, branched hydrocarbon groups, and alicyclic hydrocarbon groups. Linear hydrocarbon groups and branched hydrocarbon groups are preferable because they allow for more efficient generation of hydrated electrons and decomposition of fluorine-containing materials.

[0020] The organic group having 1 to 20 carbon atoms may be substituted with NH2 or OH. There may be at least one NH2 or OH group, and preferably one. As long as the nanoparticles targeted by the present invention can be obtained, R 21 In addition to the nitrogen or oxygen contained in NH2 or OH, it may also contain elements such as nitrogen, sulfur, and oxygen.

[0021] R21 The number of carbon atoms is preferably 1 or more. 21 The number of carbon atoms is preferably 20 or less, more preferably 12 or less, and even more preferably 6 or less. This allows for more efficient generation of hydrated electrons and decomposition of fluorine-containing materials, R 21 The number of carbon atoms is more preferably within the range described above. 21 The number of carbon atoms is more preferably 1 to 3.

[0022] In the above general formula (2), R 22 This represents H or an organic group having 1 to 6 carbon atoms. As long as the nanoparticles targeted by the present invention can be obtained, the organic group having 1 to 6 carbon atoms is not limited, and examples include aliphatic hydrocarbon groups, aromatic hydrocarbon groups, alicyclic hydrocarbon groups, etc. Examples of aliphatic hydrocarbon groups include linear hydrocarbon groups, branched hydrocarbon groups, and alicyclic hydrocarbon groups. Linear hydrocarbon groups and branched hydrocarbon groups are preferable because they allow for more efficient generation of hydrated electrons and decomposition of fluorine-containing materials.

[0023] The organic group having 1 to 6 carbon atoms may contain elements such as nitrogen, sulfur, and oxygen, as long as the nanoparticles desired by the present invention can be obtained. R 22 The number of carbon atoms is preferably 1 or more. 22 The number of carbon atoms is preferably 6 or less, more preferably 4 or less, and even more preferably 2 or less. This allows for more efficient generation of hydrated electrons and decomposition of fluorine-containing materials, 22 The number of carbon atoms is more preferably within the range described above. 22 The number of carbon atoms is more preferably 1 to 2.

[0024] R 21 This indicates an organic group with 1 to 6 carbon atoms, R 22 It is even more preferable that it represents H. The organic ligand represented by the general formula (2) above is more preferably expressed by the following formula. -S-CH2-COOH, -S-C2H4-COOH -S-CH2-CH(NH2)-COOH, -S-CH2-CH(CH3)-COOH -S-CH2-COOCH3, -S-C2H4-COOCH3

[0025] In another abstract, the present invention states that The following general formula (1') CdX (1') [In formula (1'), X represents a Group 16 element.] Particles represented by are doped and / or adsorbed with transition metals, On the surface of the particle, the following general formula (2') -SR 21 -COOR 22 (2') [In formula (2'), R 21 R represents an organic group having 3 to 20 carbon atoms, which may be substituted with NH2 or OH. 22 This indicates H, or R 21 R represents an organic group having 1 to 20 carbon atoms, which may be substituted with NH2 or OH. 22 This indicates an organic group with 1 to 6 carbon atoms. The present invention provides nanoparticles containing particles having an organic ligand represented by [the given formula]. These nanoparticles are preferably used for hydration electron generation, decomposition of halogen-containing organic materials, or as photochromic materials.

[0026] Nanoparticles in another embodiment of the present invention are given by the following general formula (1') CdX (1') [In formula (1'), X represents a Group 16 element.] As shown, transition metals are doped and / or adsorbed. The descriptions of X and the transition metal in the above general formula (1') can be referenced to those of X and the transition metal in the above general formula (1). That is, the specific details of X and the transition metal in the above general formula (1') (e.g., examples, preferred ranges, doping rates, adsorption amounts, etc.) are the same as the specific details of X and the transition metal in the above general formula (1).

[0027] The nanoparticles of the above embodiment of the present invention have the following general formula (2') on their surface -SR 21 -COOR 22 (2') [In formula (2'), R 21 R represents an organic group having 3 to 20 carbon atoms, which may be substituted with NH2 or OH. 22 This indicates H, or R 21 R represents an organic group having 1 to 20 carbon atoms, which may be substituted with NH2 or OH. 22 This represents an organic group having 1 to 6 carbon atoms. It contains particles having an organic ligand represented by [ ].

[0028] In the above general formula (2'), R 21 This represents an organic group having 3 to 20 carbon atoms, which may be substituted with NH2 or OH, and R 22 This can represent H. As long as the nanoparticles targeted by the present invention can be obtained, the organic group having 3 to 20 carbon atoms is not limited, and examples include aliphatic hydrocarbon groups, aromatic hydrocarbon groups, alicyclic hydrocarbon groups, etc. Examples of aliphatic hydrocarbon groups include linear hydrocarbon groups, branched hydrocarbon groups, and alicyclic hydrocarbon groups. Linear hydrocarbon groups and branched hydrocarbon groups are preferable because they allow for more efficient generation of hydrated electrons and decomposition of fluorine-containing materials.

[0029] The organic group having 3 to 20 carbon atoms may be substituted with NH2 or OH. There may be at least one NH2 or OH group, and preferably one. As long as the nanoparticles targeted by the present invention can be obtained, R 21 In addition to the nitrogen or oxygen contained in NH2 or OH, it may also contain elements such as nitrogen, sulfur, and oxygen.

[0030] R 21 The number of carbon atoms is preferably 3 or more. 21The number of carbon atoms is preferably 20 or less, more preferably 12 or less, and even more preferably 6 or less. This allows for more efficient generation of hydrated electrons and decomposition of fluorine-containing materials, R 21 The number of carbon atoms is more preferably within the range described above. 21 The number of carbon atoms is more preferably 3 to 6.

[0031] On the other hand, in the above general formula (2'), R 21 This represents an organic group having 1 to 20 carbon atoms, which may be substituted with NH2 or OH, and R 22 This can represent an organic group having 1 to 6 carbon atoms. As long as the nanoparticles targeted by the present invention can be obtained, R 21 The organic group having 1 to 20 carbon atoms is not limited, and examples include aliphatic hydrocarbon groups, aromatic hydrocarbon groups, alicyclic hydrocarbon groups, etc. Examples of aliphatic hydrocarbon groups include linear hydrocarbon groups, branched hydrocarbon groups, and alicyclic hydrocarbon groups. Linear hydrocarbon groups and branched hydrocarbon groups are preferable because they allow for more efficient generation of hydrated electrons and decomposition of fluorine-containing materials.

[0032] R 21 The organic group having 1 to 20 carbon atoms may be substituted with NH2 or OH. There may be at least one NH2 or OH group, and preferably one. As long as the nanoparticles targeted by the present invention can be obtained, 21 In addition to the nitrogen or oxygen contained in NH2 or OH, it may also contain elements such as nitrogen, sulfur, and oxygen.

[0033] R 21 The number of carbon atoms is preferably 1 or more. 21 The number of carbon atoms is preferably 20 or less, more preferably 12 or less, and even more preferably 6 or less. This allows for more efficient generation of hydrated electrons and decomposition of fluorine-containing materials, R 21 The number of carbon atoms is more preferably within the range described above. 21The number of carbon atoms is more preferably 1 to 3.

[0034] As long as the nanoparticles targeted by this invention can be obtained, R 22 The organic group having 1 to 6 carbon atoms is not limited, and examples include aliphatic hydrocarbon groups, aromatic hydrocarbon groups, and alicyclic hydrocarbon groups. Examples of aliphatic hydrocarbon groups include linear hydrocarbon groups, branched hydrocarbon groups, and alicyclic hydrocarbon groups. Linear hydrocarbon groups and branched hydrocarbon groups are preferable because they allow for more efficient generation of hydrated electrons and decomposition of fluorine-containing materials.

[0035] The organic group having 1 to 6 carbon atoms may contain elements such as nitrogen, sulfur, and oxygen, as long as the nanoparticles desired by the present invention can be obtained. R 22 The number of carbon atoms is preferably 1 or more. 22 The number of carbon atoms is preferably 6 or less, more preferably 4 or less, and even more preferably 2 or less. This allows for more efficient generation of hydrated electrons and decomposition of fluorine-containing materials, 22 The number of carbon atoms is more preferably within the range described above. 22 The number of carbon atoms is more preferably 1 to 2.

[0036] The organic ligand represented by the above general formula (2') is more preferably expressed by the following formula. -S-CH2-CH(CH3)-COOH -S-CH2-COOCH3, -S-C2H4-COOCH3

[0037] The average particle size of the nanoparticles in the embodiments of the present invention is preferably 1 nm or more, and more preferably 2 nm or more. The average particle size of the nanoparticles in the embodiments of the present invention is preferably 100 nm or less, more preferably 60 nm or less, even more preferably 30 nm or less, and even more preferably 10 nm or less. When the average particle size of the nanoparticles is within the above range, Auger recombination, a nonlinear reaction necessary for hydration electron generation, can be produced more efficiently.

[0038] In this specification, the average particle size described above can be calculated based on the linewidth of the scattering peak measured using a sample-horizontal multi-purpose X-ray diffraction system (e.g., Rigaku Ultima IV).

[0039] In an embodiment of the present invention, a nanoparticle dispersion is provided in which the above-mentioned nanoparticles are dispersed in a dispersion medium. To utilize the nanoparticles of the embodiment of the present invention, it is convenient to manufacture and use a dispersion in which the nanoparticles are dispersed in a dispersion medium. The dispersion medium is not particularly limited, but for example, water can be used, and an aqueous dispersion is preferred.

[0040] The nanoparticle content in the nanoparticle dispersion is preferably 0.1 to 30% by mass, more preferably 0.3 to 20% by mass, even more preferably 0.5 to 10% by mass, and even more preferably 1.0 to 7.0% by mass, based on 100% by mass of the dispersion. When the nanoparticle content is within the above range, the generation of hydrated electrons, the decomposition of fluorine-containing materials, etc., can be carried out more efficiently.

[0041] The temperature of the nanoparticle dispersion is not particularly limited, but is preferably 0 to 50°C, more preferably 0 to 40°C, and even more preferably 0 to 30°C. When the temperature of the nanoparticle dispersion is within the above range, the nanoparticles can be dispersed more uniformly, and the generation of hydrated electrons, decomposition of fluorine-containing materials, etc., can be carried out more efficiently.

[0042] The nanoparticles of the embodiments of the present invention can be used to generate hydrated electrons, and the present invention can provide a method for generating hydrated electrons using such hydrated electron-generating nanoparticles. The present invention can provide a method for generating hydrated electrons, which includes irradiating the above-mentioned nanoparticles for generating hydrated electrons with visible light or ultraviolet light.

[0043] The nanoparticles of embodiments of the present invention can be used to decompose halogen-containing organic materials, and the present invention can provide a method for decomposing halogen-containing organic materials using such halogen-containing organic material decomposition nanoparticles. The present invention relates to a method for decomposing halogen-containing organic materials, comprising irradiating the above-mentioned halogen-containing organic material decomposition nanoparticles with visible light or ultraviolet light to break the halogen-carbon bond in the halogen-containing organic material.

[0044] The nanoparticles of the embodiments of the present invention can be used to manufacture photochromic materials. Using the nanoparticles of the embodiments of the present invention, photochromic materials with short reaction times for photochromic reactions can be manufactured. The nanoparticles of the embodiments of the present invention can be suitably used for photochromic materials. [Examples]

[0045] The present invention will be described in detail below with reference to examples and comparative examples, but these examples represent only one aspect of the present invention, and the present invention is not limited in any way by these examples. In the descriptions of the examples, unless otherwise specified, portions that do not consider the solvent are given as reference values ​​in parts by weight and weight percent.

[0046] Example 1. Synthesis of Cu-doped CdS nanocrystals coordinated with mercaptopropionic acid (MPA) and decomposition of perfluorooctanesulfonic acid (PFOS). (synthesis) In a 300 mL three-necked flask, 0.091 g (0.50 mmol) of CdCl2 and 0.132 g (1.25 mmol) of mercaptopropionic acid (MPA) were dissolved in 90 mL of Milli-Q water, and the pH was adjusted to 11 using a 2 M NaOH aqueous solution. Furthermore, 0.4 mg (0.0025 mmol) of CuCl2·H2O and 0.6 mg (0.0062 mg) of MPA were dissolved in 1 mL of Milli-Q water, adjusted to pH=11, and mixed with the aforementioned aqueous solution. After bubbling the mixture with nitrogen for 30 minutes while stirring, the oil bath was raised to 100°C and the mixture was heated. 0.088 g (0.25 mmol) of Na2S·9H2O dissolved in 9 mL of Milli-Q water was quickly added to the mixture and reacted under reflux for 4 hours. 100 mL of methanol was added to the reactant to precipitate it, and after centrifugation at 8500 rpm, the precipitate was vacuum-dried under light shielding to obtain a solid. Based on the structural identification below, it is considered to be a Cu-doped Cds nanocrystal with the target MPA coordinated.

[0047] Figure 1 shows the ultraviolet-visible absorption spectrum of the nanocrystal of Example 1. The particle size of the nanocrystal of Example 1 was calculated from the first exciton peak wavelength (λnm) of the absorption spectrum in Figure 1 using the following formula. The first exciton peak wavelength was 427.5 nm, and the particle size was determined to be 4.3 nm. D(nm) = (-6.6521 × 10) -8 )λ 3 +(1.9557 × 10 -4 )λ 2 -(9.2352×10⁻²)λ+(13.29)

[0048] Figure 2 shows the FTIR absorption spectrum of the nanocrystals from Example 1. The measurement was performed using the KBr tablet method, with 256 integrations and a resolution of 0.5 cm². -1 That is the case. 2500cm derived from MPA -1Since no SH stretching vibrations are observed, SH bonds are not present. Furthermore, because thiolate anions are known to bond more strongly to semiconductor nanocrystals than carboxylate anions, it is thought that thiolate anions are coordinated to the surface of the nanoparticles. Also, 1560 cm -1 and 1400cm -1 The two peaks visible nearby are attributed to the symmetric and asymmetric stretching vibrations of the carboxylate anion in MPA, respectively. Also, 2900-3600 cm -1 A broad peak was observed over this range, which is thought to originate from hydrogen bonding between carboxylate anions on the nanocrystal surface and surface-adsorbed water.

[0049] Figure 3 shows the XRD spectrum of the nanocrystal from Example 1. The number of integration cycles was 8, indicating that it is of the zincblende type. The molar ratio of Cd to Cu was Cd:Cu = 1:0.005.

[0050] (Photodegradation reaction) Solution preparation 5.0 mg of the nanocrystals from Example 1 were weighed out and added to 3 mL of heavy water. Triethanolamine (TEOA) (100 mg, 0.67 mmol) and perfluorooctanesulfonic acid (PFOS) (2 mg, 4.3 × 10⁻⁶) were added to the solution. -3 mmol was added to prepare the solution (PFOS nanoparticle solution of Example 1). As a standard substance for NMR, 4-(trifluoromethyl)benzoic acid (2.2 mg, 1.2 × 10⁻⁶) -2 An NMR standard solution was prepared by adding mmol) and TEOA (42 mg, 0.28 mmol) to 3 mL of heavy water.

[0051] Decomposition reaction Transfer 350 mg of the PFOS nanoparticle solution and 150 mg of the NMR standard solution from Example 1 to an NMR sample tube. 19 FNMR was measured (0h). The PFOS nanoparticle solution from Example 1 was transferred to a 1 cm cell and exposed to visible light (405 nm, 0.89 W / cm²). 2The sample was irradiated with visible light for 6 hours and 24 hours. 350 mg of the PFOS nanoparticle solution from Example 1 after visible light irradiation was transferred to an NMR sample tube. 19 FNMR was measured at (6h) and (24h). Figure 4 shows the results before and after visible light irradiation. 19 The FNMR measurement results are shown. Using the peak integral value at 0h as the reference value, the dissociation rate of CF bonds was calculated from the integral value of fluoride ions. It was 3% at 6h and 58% at 24h. The number of integration cycles was 64, and the molar ratio of nanocrystals to PFOS in Example 1 was 1:80. In Example 1, the decomposition of PFOS by nanocrystals was carried out with a nanocrystal:PFOS molar ratio of 1:80. Since the nanocrystals precipitated after decomposition, it was found that they acted as a heterogeneous catalyst. Referring to the comparative example described later, it was found that the Cu-doped nanocrystals of Example 1 had superior decomposition efficiency.

[0052] Furthermore, apart from not using TEOA as a hole trapping material and reacting with nanocrystals:PFOS in a molar ratio of 1:16, the decomposition of PFOS by nanocrystals in Example 1 was carried out using the same method as described above for the decomposition of PFOS by nanocrystals in Example 1. Figure 5 shows the results before and after visible light irradiation. 19 The FNMR measurement results are shown. It can be seen that the efficiency of the decomposition reaction decreases without the addition of TEOA, a hole trapping agent, but the decomposition proceeds in proportion to the amount of nanocrystals.

[0053] Example 2. Decomposition of polytetrafluoroethylene (PTFE) by Cu-doped CdS nanocrystals coordinated with mercaptopropionic acid (MPA). (Photodegradation reaction) Solution preparation 15 mg of the nanocrystals from Example 1 were weighed out and added to 2 mL of Milli-Q water. TEOA (100 mg, 0.67 mmol) and polytetrafluoroethylene (PTFE) (100 mg) were added to this solution to obtain a PTFE nanoparticle preparation solution. As a standard substance for NMR, 4-(trifluoromethyl)benzoic acid (2.2 mg, 1.2 × 10⁻⁶) -2An NMR standard solution was prepared by adding mmol) and TEOA (42 mg, 0.28 mmol) to 3 mL of heavy water.

[0054] Decomposition reaction Transfer 350 mg of the PTFE nanoparticle solution and 150 mg of the NMR standard solution from Example 2 to an NMR sample tube. 19 FNMR was measured (0h). The PTFE nanoparticle solution from Example 2 was transferred to a 1 cm cell and exposed to visible light (405 nm, 0.89 W / cm²). 2 The solution was irradiated with visible light for 18 hours and 42 hours. 350 mg of the PTFE nanoparticle solution from Example 2 after visible light irradiation was transferred to an NMR sample tube. 19 FNMR was measured at (18h) and (42h). Figure 6 shows the results before and after visible light irradiation. 19 The FNMR measurement results are shown. It can be seen that F ions are generated over time. Since PTFE is insoluble in water and water-repellent, an excess amount (100 mg) was added to increase the probability of contact with the nanocrystalline solution during light irradiation. Due to the excess amount added, the decomposition rate was low, but in the sample irradiated for 42 hours, the water-repellent function of PTFE decreased and it also showed behavior such as floating in the solution. Furthermore, the F peak seen after 42 hours has a sufficiently high concentration, suggesting that further decomposition will occur if the time is extended even more.

[0055] Comparative Example 1. Synthesis of MPA-coordinated CdS nanocrystals and decomposition of PFOS using them. (synthesis) Except for not using the Milli-Q solution of CuCl2·H2O and MPA, a solid was obtained using the same method as the nanocrystal manufacturing method described in Example 1. Based on the structural identification below, it is considered to be the MPA-coordinated Cds nanocrystal of Comparative Example 1, which was the target.

[0056] Figure 7 shows the ultraviolet-visible absorption spectrum of the nanocrystal of Comparative Example 1. The particle size of the nanocrystal of Comparative Example 1 was calculated from the absorption spectrum in Figure 7 using the formula described in Example 1. The first exciton peak was at 432 nm, and the particle size was determined to be 4.5 nm.

[0057] Figure 8 shows the FTIR absorption spectrum of the nanocrystals of Comparative Example 1. Measured by the KBr tablet method, the number of integrations was 256, and the resolution was 0.5 cm -1 is used. The S-H stretching vibration existing at 2500 cm -1 derived from MPA is not observed, so the S-H bond does not exist. Also, since it is known that the thiolate anion binds more strongly to the semiconductor nanocrystal than the carboxylate anion, it is considered that the thiolate anion is coordinated on the surface of the nanoparticles. Further, the two peaks visible around 1560 cm -1 and 1400 cm -1 are respectively attributed to the symmetric stretching vibration and the asymmetric stretching vibration of the carboxylate anion of MPA. Also, a broad peak thought to be derived from the hydrogen bond between the carboxylate anion on the surface of the nanocrystal and surface-adsorbed water, etc. was observed in the range of 2900 - 3600 cm -1 .

[0058] Figure 9 shows the XRD spectrum of the nanocrystals of Comparative Example 1. The number of integrations was 8, and it can be seen that it is of the sphalerite type.

[0059] (Photodegradation reaction) Solution preparation A PFOS nanoparticle solution and an NMR standard solution of Comparative Example 1 were prepared in the same manner as the method described in Example 1, except that the nanocrystals of Comparative Example 1 were used instead of the nanocrystals of Example 1.

[0060] Decomposition reaction The method described in Example 1 was used, except that the PFOS nanocrystal solution of Comparative Example 1 was used instead of the PFOS nanoparticle solution of Example 1. 19 FNMR was measured at (0 h), (6 h), and (24 h). Figure 10 shows the 19 FNMR measurement results before and after visible light irradiation. Based on the peak integral value at 0 h as the reference value, the dissociation ratio of the CF bond was calculated from the integral value of fluoride ions. It was 0.4% at 6 h and 53% at 24 h. The number of integrations was 64, and the molar ratio of the nanocrystals and PFOS of Comparative Example 1 was 1:72.

[0061] Comparative Example 2. Synthesis of Cu-doped CdS Nanocrystals and Degradation of PFOS Using the Same (Synthesis) In a 300 mL three-neck flask, 0.091 g (0.50 mmol) of CdCl2 was dissolved in 90 mL of Milli-Q water. Also, 0.4 mg (0.0025 mmol) of CuCl2·H2O and 0.6 mg (0.0062 mg) of MPA were dissolved in 1 mL of Milli-Q water, adjusted to pH = 11, and mixed with the above aqueous solution. While stirring the mixture, nitrogen was bubbled for 30 minutes, then the oil bath was heated to 100 °C to heat the mixture, and 0.088 g (0.25 mmol) of Na2S·9H2O dissolved in 9 mL of Milli-Q water was quickly added to the mixture, and the reaction was carried out for 4 hours while refluxing. 100 mL of methanol was added to the reaction product to precipitate, and after centrifuging at 8500 rpm, the precipitate was vacuum dried under light shielding to obtain a solid. It is considered to be the target Cu-doped Cds nanocrystals from the following structure identification.

[0062] Figure 11 shows the FTIR absorption spectrum of the nanocrystals of Comparative Example 2. Measured by the KBr tablet method, the number of integrations is 256 times, and the resolution is 0.5 cm -1 is. Figure 12 shows the XRD spectrum of the nanocrystals of Comparative Example 2. The number of integrations is 8 times, and it can be seen that it is of the sphalerite type.

[0063] (Photodegradation Reaction) Solution Preparation Except for using the nanocrystals of Comparative Example 2 instead of the nanocrystals of Example 1, a PFOS nanoparticle solution and an NMR standard solution of Comparative Example 2 were prepared in the same manner as described in Example 1.

[0064] Degradation Reaction Except for using the PFOS nanocrystal solution of Comparative Example 2 instead of the PFOS nanoparticle solution of Example 1, the method described in Example 1 was used to 19 19F NMR was measured at (0 h), (6 h), and (24 h). Figure 13 shows before and after visible light irradiation 19The FNMR measurement results are shown. Using the peak integral value at 0h as the reference value, the dissociation rate of CF bonds was calculated from the integral value of fluoride ions. It was 0.07% at 6h and 2% at 24h. [Industrial applicability]

[0065] Using the nanoparticles of the embodiments of the present invention, hydrated electrons can be generated using a light source that is lower in energy, smaller in size, and less expensive. These nanoparticles do not contain rare metals such as iridium, are less costly, more sustainable (lower country risk), and more versatile. Furthermore, using the nanoparticles of the embodiments of the present invention, a method for decomposing fluorine-containing compounds can be provided, as can photochromic materials.

Claims

1. The following general formula (1) CdX (1) [In formula (1), X represents a Group 16 element.] Particles represented by are doped and / or adsorbed with transition metals, On the surface of the particle, the following general formula (2) -S-R ２１ -COOR ２２ (2) [In formula (2), R ２１ NH ２ Alternatively, it may represent an organic group having 1 to 20 carbon atoms that may be substituted with OH, R ２２ This represents H or an organic group having 1 to 6 carbon atoms. Nanoparticles containing particles having an organic ligand represented by , for use in generating hydrated electrons, decomposing halogen-containing organic materials, or as photochromic materials.

2. The following general formula (1') CdX (1') [In formula (1'), X represents a Group 16 element.] Particles represented by are doped and / or adsorbed with transition metals, On the surface of the particle, the following general formula (2') -S-R ２１ -COOR ２２ (2’) [In formula (2'), R ２１ represents an organic group having 3 to 20 carbon atoms which may be substituted with NH ２ or OH, R ２２ represents H, or R ２１ represents an organic group having 1 to 20 carbon atoms which may be substituted with NH ２ or OH, and R ２２ represents an organic group having 1 to 6 carbon atoms.] Nanoparticles containing particles having an organic ligand represented by .

3. R ２１ This represents an organic group with 1 to 6 carbon atoms, R ２２ The nanoparticle according to claim 1, wherein H is represented.

4. The nanoparticle according to claim 1 or 2, wherein X is at least one selected from O, S, Se, or Te.

5. The nanoparticles according to claim 1 or 2, wherein the average particle diameter is 1 nm or more and 100 nm or less.

6. The nanoparticle according to claim 1 or 2, wherein the doping rate of the transition metal to Cd in formula (1) is 0.01 to 10.0 mol%.

7. A nanoparticle aqueous dispersion in which the nanoparticles described in claim 1 or 2 are dispersed in water.

8. Nanoparticles according to claim 2 for generating hydrated electrons, decomposing halogen-containing organic materials, or photochromic materials

9. A method for generating hydrated electrons using the hydrated electron generating nanoparticles described in claim 1 or 8.

10. A method for generating hydrated electrons according to claim 9, comprising irradiating the nanoparticles for generating hydrated electrons according to claim 1 or 8 with visible light or ultraviolet light.

11. A method for decomposing halogen-containing organic materials, using halogen-containing organic material decomposition nanoparticles according to claim 1 or 8.

12. A method for decomposing halogen-containing organic materials, comprising irradiating the halogen-containing organic material decomposition nanoparticles described in claim 1 or 8 with visible light or ultraviolet light to break the halogen-carbon bond in the halogen-containing organic material.

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