A method to make Ti3C2T x Long-term preservation method of Mecoene

Abstract

The present invention relates to Ti3C2T x The field of meikeene preservation technology is a kind of Ti3C2T x The method comprises the following steps: (1) preparing Ti3C2T by a mild method of in-situ generation of HF by HCl and LiF; x Mecoene nanosheet suspension; (2) Ti3C2T x A certain proportion of a preservative is added to the suspension of the mecoene nanosheets. In the present invention, a certain proportion of at least one of ethylene glycol, propylene glycol, glycerol, polyglycerol and other polyols is added to the above Ti3C2T x In the mecoene suspension, Ti3C2T x Mecoene is chemically stable and can maintain Ti3C2T for a long time x Mecoene does not deteriorate, and the process is simple and easy to operate. x The inherent problem of the long-term storage of mecoene suspension is that it is easy to oxidize, which makes Ti3C2T x The large-scale commercialization of mecoene has become a reality. The present invention is suitable for preserving various mecoene materials, especially some mecoene materials that are easily oxidized.

Description

Technical Field

[0001] The present invention relates to Ti3C2T x In the field of MXene fresh-keeping technology, specifically a method of making Ti3C2T x Long-term preservation method of MXene. Background Art

[0002] MXene is a new type of two-dimensional transition metal carbon / nitride. In 2011, Gogotsi Yurry's research group first used 50% HF stock solution to selectively extract the Al layer atoms in Ti3AlC2 to obtain the first two-dimensional layered MXene Ti3C2T x (Naguib M, Kurtoglu M, Presser V, et al. Two-dimensional nanocrystals produced by exfoliation of Ti3AlC2[J]. Advanced materials, 2011, 23(37): 4248-4253.) The chemical formula of this two-dimensional material is generally expressed as M n+1 X n T x , where: M is an early transition metal, such as Ti, V, Nb, Mo, etc.; X is carbon or nitrogen; T xRepresents surface functional groups, such as -F, -O, -OH or -Cl, etc. Due to its unique physical and chemical properties, research and applications based on MXenes are constantly emerging, especially in the fields of batteries, supercapacitors, electronic sensors, electromagnetic interference shielding and electrocatalysis (Hu T, Yang J, Li W, et al. Quantifying the rigidity of 2D carbides (MXenes) [J]. Physical Chemistry Chemical Physics, 2020, 22 (4): 2115-2121; Hu M, Zhang H, Hu T, et al. Emerging 2D MXenes for supercapacitors: status, challenges and prospects [J]. Chemical Society Reviews, 2020, 49 (18): 6666-6693; Anasori B, Lukatskaya MR, Gogotsi Y. 2D metal carbides and nitrides (MXenes) for energy storage [J]. Nature Reviews Materials, 2017, 2 (2): 1-17.).

[0003] Although mechanoene is favored for its unique physical and electrochemical properties, its easy oxidation leads to structural collapse and functional loss, which limits the further development and application of this material. x After the single-layer or few-layer nanosheets of mecoene are prepared, the few-layer nanosheets can be well dispersed in deionized water to form a suspension, so that more Ti3C2T x The surface and edge of the mechanoene are exposed to air and water, making Ti3C2T x The oxidation problem of mecoene has become more prominent, seriously hindering the Ti3C2T x Scientific research and application of meconene materials (Ghidiu M, Lukatskaya MR, Zhao MQ, et al. Conductive two-dimensional titanium carbide'clay'with high volumetric capacitance[J]. Nature, 2014, 516(7529):78-81.).

[0004] To solve the problem of Ti3C2T xResearchers have been exploring breakthroughs in the problem of easy oxidation of MXene and have carried out a lot of scientific research. The literature (Zhang CJ, Pinilla S, McEvoy N, et al. Oxidation stability of colloidal two-dimensional titanium carbides (MXenes) [J]. Chemistry of Materials, 2017, 29 (11): 4848-4856.) reported that Ti3C2T x The mecoene suspension will be severely oxidized and degraded after being stored in an open reagent bottle for 15 days; the literature (Habib T, Zhao X, Shah SA, et al. Oxidationstability of Ti3C2T x MXene nanosheets in solvents and composite films[J].NPJ2D Materials and Applications, 2019,3(1):1-6.) Confirmed Ti3C2T x The oxidation rate of mechanoene nanosheets is closely related to the storage medium. x The oxidation rate of MXene nanosheets in water is significantly higher than that in organic solvents such as acetone and acetonitrile. The literature (Natu V, Hart JL, Sokol M, et al. Edge capping of 2D-MXene sheets with polyanionic salts to mitigate oxidation in aqueous colloidal suspensions [J]. Angewandte Chemie, 2019, 131 (36): 12785-12790.) confirms that in Ti3C2T x Adding some polyanionic compounds to the suspension of meikeene nanosheets can alleviate oxidation, Ti3C2T x Mecoene nanosheets can be stored for weeks. Although existing technical strategies have slowed down the degradation of Ti3C2T x The oxidation rate of mechanoene nanosheets is x Suspensions of mechanoene nanosheets are challenging.

[0005] In summary, keep Ti3C2T x The long-term stability of mechanoene nanosheet suspensions is the basis for their large-scale commercialization. Summary of the invention

[0006] In order to overcome the shortcomings of the prior art, the present invention provides a Ti3C2T x MXene long-term preservation method can simply and quickly keep Ti3C2T x The long-term stability of the mecoene suspension solves the problem of Ti3C2T x The problem of easy oxidation in the mecoene suspension can meet the future Ti3C2T x Requirements for the commercialization of mecoene suspensions.

[0007] The technical solution of the present invention is:

[0008] A method to make Ti3C2T x The method for preserving the maikeene for a long time comprises the following steps:

[0009] (1) First, Ti3AlC2 powder is used as a precursor and soaked in 3-12 mol·L -1 In a mixed aqueous solution of HCl and LiF, in which the molar ratio of LiF to Ti3AlC2 is (3-15):1, HF is generated in situ by HCl and LiF, and the Al atomic layer in Ti3AlC2 is selectively etched away to obtain Ti3C2T x The two-dimensional layered material was washed and filtered with deionized water; then Ti3C2T x The two-dimensional layered material is dispersed in deionized water, shaken or ultrasonicated, and then centrifuged to take the upper layer of liquid, which is the ultra-thin two-dimensional Ti3C2T x Nanosheet suspension;

[0010] (2) Add polyol as a preservative to the Ti3C2T x After uniform mixing in the nanosheet suspension, Ti3C2T x Nanosheet suspensions stay fresh for a long time.

[0011] The Ti3C2T x The method for preserving Maicoene for a long time, in step (1), Ti3AlC2 is a porous body sintered without pressure, and then mechanically crushed into powder.

[0012] The Ti3C2T x The method for preserving maikoene for a long time comprises the following steps: in step (1), in a mixed aqueous solution of HCl and LiF, the molar ratio of HCl to LiF is (2-10):1.

[0013] The Ti3C2T x The method for preserving maikoene for a long time, in step (2), the polyol used as a preservative is one or more of any polyol of C2 to C16 and its polymer.

[0014] The Ti3C2T x The long-term preservation method of Maikoene, preferably, the preservative is at least one of ethylene glycol, propylene glycol, glycerol and polyglycerol.

[0015] The Ti3C2T x Long-term preservation method of Maicoene, propylene glycol and Ti3C2T in preservative x The volume ratio of the nanosheet suspension is (0.5-10):1, and other polyols and Ti3C2T x The volume ratios of the nanosheet suspensions are (0-10):1.

[0016] The Ti3C2T x The method for preserving the freshness of the maikoene for a long time, in step (2), adding the preservative to Ti3C2T x In the nanosheet suspension, Ti3C2T x The nanosheet suspension was prepared with deionized water to a concentration of 5-15 mg mL -1 .

[0017] The Ti3C2T x The method for preserving the freshness of maikeene for a long time, wherein in step (1), ultra-thin two-dimensional Ti3C2T x The thickness of the nanosheets is 0.5 to 1.5 nm.

[0018] The design concept of the present invention is:

[0019] The present invention utilizes a preservative (such as polyols such as ethylene glycol, propylene glycol, glycerol, polyglycerol, etc.) which can be miscible with deionized water in any proportion and can be uniformly coated on the Ti3C2T x The mecoene nanosheets do not affect the Ti3C2T x Due to the dispersibility of the Mecoene nanosheets, a certain proportion of preservatives and Ti3C2T x Mixed with the suspension of mecoene nanosheets, the preservative can wrap the Ti3C2T x Mecoene nanosheets avoid direct contact with water and oxygen, fundamentally solving the problem of Ti3C2T x The problem of easy oxidation of mechanoene nanosheet suspension.

[0020] The present invention utilizes the above alcohol to maintain Ti3C2T x To improve the integrity of the Mecoene structure, a certain proportion of at least one of the polyols such as ethylene glycol, propylene glycol, glycerol, polyglycerol, etc. is added to the above Ti3C2T x In the mecoene suspension, Ti3C2T x Mecoene is chemically stable and can maintain Ti3C2T for a long time xMecoene does not deteriorate, and the process is simple and easy to operate.

[0021] The advantages and beneficial effects of the present invention are:

[0022] 1. The present invention uses a preservative (such as polyols such as ethylene glycol, propylene glycol, glycerol, polyglycerol, etc.) to wrap the Ti3C2T x Mecoene nanosheets isolate deionized water from oxygen, making it easy to control and operate. x The mechanoene nanosheet suspension remains similar to fresh Ti3C2T after several months. x The suspension of mecoene nanosheets is the same as that of Ti3C2T. x The inherent difficulty of long-term storage of mecoene nanosheet suspensions is that they are easily oxidized, which makes Ti3C2T x The large-scale commercialization of Mecoene has become a reality.

[0023] 2. The preservative of the present invention has an effect on Ti3C2T x The chemical stability of mecoene nanosheets has been significantly improved, and their structure remains the same for more than half a year.

[0024] 3. Preparation of Ti3C2T3 after adding preservative by the present invention x The suspension of mecoene nanosheets still maintains good dispersibility. The preservative of the present invention can be applied to other two-dimensional layered materials that are easily oxidized, and has broad application prospects.

[0025] 4. The present invention is applicable to the preservation of various mecoene materials, especially some mecoene materials that are easily oxidized and degraded. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The Ti3C2T prepared in Example 1 x Optical photograph of the mechoene suspension.

[0027] Figure 2 is Ti3C2T in Example 1 x Optical photographs of the changes of the mecoene suspension with and without the addition of preservatives over time.

[0028] Figure 3 is Ti3C2T in Example 2 x Optical photographs of the changes of the mecoene suspension with and without the addition of preservatives over time.

[0029] Figure 4 is Ti3C2T in Example 2 xRaman spectra of the Mecoene suspension after adding preservatives at different times. a represents the Raman spectrum of the freshly added preservative, b represents the Raman spectrum of the 27th day after adding preservatives, and c represents the Raman spectrum of the 70th day after adding preservatives.

[0030] Figure 5 The fresh Ti3C2T in Example 2 x Cross section of the membrane through which the mechoene suspension was filtered.

[0031] Figure 6 is Ti3C2T in Example 2 x Cross-section of the filtration membrane 70 days after the addition of glycerol to the mecoene suspension. DETAILED DESCRIPTION

[0032] In the specific implementation process, the present invention proposes a method for making Ti3C2T x The method for preserving MXene for a long time comprises the following steps: (1) preparing Ti3C2T by a mild method of in-situ generating HF by HCl and LiF; x Mecoene nanosheet suspension; (2) Ti3C2T x A certain proportion of preservatives (polyols such as ethylene glycol, propylene glycol, glycerol, polyglycerol, etc.) is added to the suspension of mecoene nanosheets. This method not only solves the problem of Ti3C2T x The suspension of mecoene nanosheets is difficult to preserve for a long time and is easily oxidized. At the same time, the preparation process is simple, fast and easy to commercialize.

[0033] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. However, the following embodiments are merely simple examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0034] The feasibility of the present invention is further verified by examples below.

[0035] Example 1

[0036] In this embodiment, a method of making Ti3C2T x The specific steps of the MXene long-term preservation method are as follows:

[0037] (1) Using Ti3AlC2 powder as the precursor, soak it in 9 mol·L -1 Ti3C2T xThe two-dimensional layer was washed with deionized water five times and filtered; then the Ti3C2T x The material is dispersed in deionized water, shaken or ultrasonicated, and then centrifuged. The upper liquid is Ti3C2T x Mecoene nanosheet suspension ( Figure 1 ), Ti3C2T x The thickness of the nanosheet is about 1 nm;

[0038] (2) The above Ti3C2T x The suspension of mecoene nanosheets was diluted with deionized water to a ratio of 10 mg mL -1 ;

[0039] (3) 1 mL of the concentration is 10 mg mL -1 Ti3C2T x The suspension of meikeene nanosheets was evenly mixed with 1.5 mL of deionized water and 2.5 mL of glycerol and shaken on an oscillator for 5 min to make Ti3C2T x Suspensions of mecoene nanosheets retain freshness for a long time.

[0040] like Figure 2 As shown, Ti3C2T with glycerol added x The suspension of mecoene nanosheets did not change even after 70 days, while the sample without propylene glycol began to undergo severe oxidation and degradation after 27 days, and was completely oxidized after 70 days, turning into a white TiO2 suspension, which also confirmed the antioxidant effect of the additive.

[0041] Example 2

[0042] In this embodiment, a method of making Ti3C2T x The specific steps of the MXene long-term preservation method are as follows:

[0043] The only difference from Example 1 is that 1 mL of 10 mg mL -1 Ti3C2T x The suspension of mecoene nanosheets was evenly mixed with 4 mL of propylene glycol and shaken on an oscillator for 5 min to make Ti3C2T x Suspensions of mecoene nanosheets retain freshness for a long time.

[0044] like Figure 3 As shown, Ti3C2T with glycerol added x The suspension of mecoene nanosheets showed no change even after 70 days, while the sample without glycerol addition began to undergo severe oxidation and degradation after 27 days and was completely oxidized and turned into white TiO2 particles after 70 days.

[0045] like Figure 4 As shown, the addition of propylene glycol to Ti3C2T x The chemical structure of mecoene was not affected at all, and no TiO2 was detected after 70 days, confirming that propylene glycol has excellent ability to maintain Ti3C2T x Mecoene fresh capabilities.

[0046] like Figure 5 As shown, fresh Ti3C2T x The cross-section of the filtration membrane of the mecoene nanosheet suspension shows that the sheets are thin and wrinkled, showing good flexibility.

[0047] like Figure 6 As shown, Ti3C2T x The cross section of the filtration membrane after 70 days of adding glycerol to the mecoene suspension shows that after adding glycerol, Ti3C2T x The cross section of the filtration membrane of the mecoene nanosheet suspension still maintains complete flakes and folds, and the surface glycerol has excellent preservation ability.

[0048] Example 3

[0049] In this embodiment, a method of making Ti3C2T x The specific steps of the MXene long-term preservation method are as follows:

[0050] The only difference from Example 1 is that 1 mL of 10 mg mL -1 Ti3C2T x The mechanoene nanosheet suspension was evenly mixed with 4 mL of propylene glycol and shaken on a shaker for 5 min.

[0051] Example 4

[0052] In this embodiment, a method of making Ti3C2T x The specific steps of the MXene long-term preservation method are as follows:

[0053] The only difference from Example 1 is that 1 mL of 10 mg mL -1 Ti3C2T x The mechanoene nanosheet suspension was evenly mixed with 4 mL of ethylene glycol and shaken on a shaker for 5 min.

[0054] Comparative Example 1

[0055] In this comparative example, a Ti3C2T x The specific steps of the MXene long-term preservation method are as follows:

[0056] (1) Ti3C2T xPreparation of mecoene suspension: same as steps (1) and (2) of Example 1.

[0057] (2) Ti3C2T x The ratio of the maikoene suspension to the preservative is the same as step (3) of Example 1, except that 1 mL of the maikoene suspension is 10 mg mL -1 Ti3C2T x The suspension of meikeene nanosheets was uniformly mixed with 1.5 mL of propylene glycol and 2.5 mL of glycerol, and the preservative Ti3C2T x The suspension of mecoene nanosheets can maintain chemical stability for a long time and keep its structure intact for more than half a year.

[0058] Comparative Example 2

[0059] In this comparative example, a Ti3C2T x The specific steps of the MXene long-term preservation method are as follows:

[0060] (1) Ti3C2T x Preparation of mecoene suspension: same as steps (1) and (2) of Example 1.

[0061] (2) Ti3C2T x The ratio of the maikoene suspension to the preservative is the same as step (3) of Example 1, except that 1 mL of the maikoene suspension is 10 mg mL -1 Ti3C2T x The suspension of meikeene nanosheets was uniformly mixed with 1.5 mL of ethylene glycol and 2.5 mL of propylene glycol, and the preservative Ti3C2T x The suspension of mecoene nanosheets can maintain chemical stability for a long time and keep its structure intact for more than half a year.

[0062] The results of the embodiments and comparative examples show that the present invention can make Ti3C2T x The MXene long-term preservation method is simple, fast, low-cost, and can keep Ti3C2T for a long time. x The chemical stability of the Mecoene suspension solves the problem of Ti3C2T x The inherent problem of the mecoene suspension being easy to oxidize. The present invention is applicable to a variety of mecoene suspensions, especially to those mecoenes that are easy to oxidize, and has broad application prospects.

[0063] The above description is only a preferred embodiment of the present invention, but the implementation of the present invention is not limited to the above embodiment. Any obvious improvement, replacement, or modification made by a person skilled in the art on the basis of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for making Ti3C2T x The method for preserving the maikoene for a long time is characterized by: The steps include: (1) First, Ti3AlC2 powder is used as a precursor and soaked in 3-12 mol·L -1 In a mixed aqueous solution of HCl and LiF, the molar ratio of LiF to Ti3AlC2 is (3-15):1, and HF is generated in situ by HCl and LiF. This mild method selectively etches away the Al atomic layer in Ti3AlC2 to obtain Ti3C2T x The two-dimensional layered material was washed and filtered with deionized water; then Ti3C2T x The two-dimensional layered material is dispersed in deionized water, shaken or ultrasonicated, and then centrifuged to take the upper layer of liquid, which is the ultra-thin two-dimensional Ti3C2T x Nanosheet suspension; In step (1), Ti3AlC2 is a porous body that is sintered without pressure and then mechanically crushed into powder; (2) Adding polyol as a preservative to the Ti3C2T x After uniform mixing in the nanosheet suspension, Ti3C2T x Nanosheet suspensions stay fresh for a long time.

2. The method of claim 1 wherein Ti3C2T x The method for preserving the maikoene for a long time is characterized by: In step (1), in the mixed aqueous solution of HCl and LiF, the molar ratio of HCl to LiF is (2-10):

1.

3. The method of making Ti3C2T x The method for preserving the maikoene for a long time is characterized by: In step (2), the polyol used as a preservative is one or more of any C2 to C16 polyol and its polymer.

4. The method of making Ti3C2T x The method for preserving the maikoene for a long time is characterized by: The preservative is at least one of ethylene glycol, propylene glycol, glycerol and polyglycerol.

5. The Ti3C2T3 according to claim 3 or 4 x The method for preserving the maikoene for a long time is characterized by: In the preservative, glycerol and Ti3C2T x The volume ratio of the nanosheet suspension is (0.5-10): 1, other polyols and Ti3C2T x The volume ratios of the nanosheet suspensions are (0-10):

1.

6. The method of claim 1 for making Ti3C2T x The method for preserving the maikoene for a long time is characterized by: In step (2), a preservative is added to Ti3C2T x In the nanosheet suspension, Ti3C2T x The nanosheet suspension was prepared with deionized water to a concentration of 5-15 mg mL -1 .

7. The method of claim 1 for making Ti3C2T x The method for preserving the maikoene for a long time is characterized by: In step (1), ultrathin two-dimensional Ti3C2T x The thickness of the nanosheets is 0.5 to 1.5 nm.

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