COMPOSITE LOADED WITH NANO-MAGNESIUM HYDRIDE AND PREPARATION METHOD THEREOF

Abstract

Disclosed is a method for preparing a composite loaded with nano-magnesium hydride, including: adding a cationic surfactant into an aqueous dispersion of a two-dimensional transition metal carbide such that a nanosheet of the two-dimensional transition metal carbide wrinkles, to avoid re-stacking, and then washing and drying; placing a dried product into a sealed container, vacuuming the sealed container, heating to a high temperature, and holding at the high temperature for a period of time; filling the sealed container with high-pressure hydrogen and holding for a period of time to obtain a heated product; adding the heated product and dibutyl magnesium into an organic solvent, conducting ultrasonic dispersion, then heating under stirring at a hydrogen pressure of 3 MPa to 6 MPa and a temperature of 180? C. to 220? C. for 12 h to 48 h, and centrifuging and drying to obtain the composite loaded with nano-magnesium hydride.

Claims

1. A method for preparing a composite loaded with nano-magnesium hydride, comprising: step (1): adding a cationic surfactant into an aqueous dispersion of a two-dimensional transition metal carbide such that a nanosheet of the two-dimensional transition metal carbide wrinkles, to obtain a wrinkled two-dimensional transition metal carbide, and washing and drying the wrinkled two-dimensional transition metal carbide to obtain a dried product; step (2): placing the dried product obtained from step (1) into a sealed container, vacuuming the sealed container, heating the dried product to a temperature of 600? C. to 1,000? C., and holding the dried product at the temperature for 2 h to 5 h to obtain a heated product, and filling the sealed container with 1 MPa to 10 MPa of hydrogen and holding the heated product for 2 h to 5 h to obtain a product; and step (3): adding the product obtained from step (2) and dibutyl magnesium into an organic solvent to obtain a mixture, subjecting the mixture to ultrasonic dispersion to obtain a dispersion mixture, heating the dispersion mixture under stirring at a hydrogen pressure of 3 MPa to 6 MPa and a temperature of 180? C. to 220? C. for 12 h to 48 h to obtain a heated dispersion mixture, and centrifuging and drying the heated dispersion mixture to obtain the composite loaded with nano-magnesium hydride.

2. The method for preparing a composite loaded with nano-magnesium hydride of claim 1, wherein the two-dimensional transition metal carbide in step (1) is any one selected from the group consisting of Ti.sub.3C.sub.2T.sub.x, Ti.sub.2CT.sub.x, V.sub.2CT.sub.x, MO.sub.3C.sub.2T.sub.x, Nb.sub.2CT.sub.x, Nb.sub.4C.sub.3T.sub.x, Ta.sub.2CT.sub.x, and V.sub.4C.sub.3T.sub.x.

3. The method for preparing a composite loaded with nano-magnesium hydride of claim 1, wherein the cationic surfactant is a nitrogen-containing organic amine derivative.

4. The method for preparing a composite loaded with nano-magnesium hydride of claim 3, wherein the nitrogen-containing organic amine derivative is cetyltrimethylammonium bromide (CTAB).

5. The method for preparing a composite loaded with nano-magnesium hydride of claim 1, wherein in step (1), the cationic surfactant is dissolved in deionized water, and a resulting solution is then added into the aqueous dispersion of the two-dimensional transition metal carbide under stirring.

6. The method for preparing a composite loaded with nano-magnesium hydride of claim 1, wherein heating the dried product to a temperature of 600? C. to 1,000? C. in step (2) is conducted at a rate of 5? C./min to 10? C./min.

7. The method for preparing a composite loaded with nano-magnesium hydride of claim 1, wherein the organic solvent in step (3) comprises one or more selected from the group consisting of cyclohexane, hexane, and heptane.

8. A method for preparing a composite loaded with nano-magnesium hydride, comprising: step (1): adding acidified melamine into an aqueous dispersion of a two-dimensional transition metal carbide such that a nanosheet of the two-dimensional transition metal carbide wrinkles, to obtain a wrinkled two-dimensional transition metal carbide, and washing and drying the wrinkled two-dimensional transition metal carbide to obtain a dried product; step (2): placing the dried product obtained from step (1) into a sealed container, vacuuming the sealed container, heating the dried product to a temperature of 600? C. to 1,000? C. and holding the dried product at the temperature for 2 h to 5 h to obtain a heated product, and filling the sealed container with 1 MPa to 10 MPa of hydrogen and holding the heated product for 2 h to 5 h to obtain a product; and step (3): adding the product obtained from step (2) and dibutyl magnesium into an organic solvent to obtain a mixture, subjecting the mixture to ultrasonic dispersion to obtain a dispersion mixture, heating the dispersion mixture under stirring at a hydrogen pressure of 3 MPa to 6 MPa and a temperature of 180? C. to 220? C. for 12 h to 48 h to obtain a heated dispersion mixture, and centrifuging and drying the heated dispersion mixture to obtain the composite loaded with nano-magnesium hydride.

9. A composite loaded with nano-magnesium hydride prepared by the method of claim 1, wherein nano-magnesium hydride is loaded onto a surface of the two-dimensional transition metal carbide, and the nanosheet of the two-dimensional transition metal carbide has wrinkles.

10. The composite loaded with nano-magnesium hydride of claim 9, wherein a mass percentage of magnesium hydride in the composite loaded with nano-magnesium hydride is in a range of 20% to 75%.

11. (canceled)

12. The composite loaded with nano-magnesium hydride of claim 9, wherein the two-dimensional transition metal carbide in step (1) is any one selected from the group consisting of Ti.sub.3C.sub.2T.sub.x, Ti.sub.2CT.sub.x, V.sub.2CT.sub.x, MO.sub.3C.sub.2T.sub.x, Nb.sub.2CT.sub.x, Nb.sub.4C.sub.3T.sub.x, Ta.sub.2CT.sub.x, and V.sub.4C.sub.3T.sub.x.

13. The composite loaded with nano-magnesium hydride of claim 9, wherein the cationic surfactant is a nitrogen-containing organic amine derivative.

14. The composite loaded with nano-magnesium hydride of claim 13, wherein the nitrogen-containing organic amine derivative is cetyltrimethylammonium bromide (CTAB).

15. The composite loaded with nano-magnesium hydride of claim 9, wherein in step (1), the cationic surfactant is dissolved in deionized water, and a resulting solution is then added into the aqueous dispersion of the two-dimensional transition metal carbide under stirring.

16. The composite loaded with nano-magnesium hydride of claim 9, wherein heating the dried product to a temperature of 600? C. to 1,000? C. in step (2) is conducted at a rate of 5? C./min to 10? C./min.

17. The composite loaded with nano-magnesium hydride of claim 9, wherein the organic solvent in step (3) comprises one or more selected from the group consisting of cyclohexane, hexane, and heptane.

18. A composite loaded with nano-magnesium hydride prepared by the method of claim 8, wherein nano-magnesium hydride is loaded onto a surface of the two-dimensional transition metal carbide, and the nanosheet of the two-dimensional transition metal carbide has wrinkles.

19. The composite loaded with nano-magnesium hydride of claim 18, wherein a mass percentage of magnesium hydride in the composite loaded with nano-magnesium hydride is in a range of 20% to 75%.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] FIG. 1 shows an X-ray diffraction (XRD) pattern of a composite loaded with magnesium hydride on two-dimensional transition metal carbide according to one embodiment of the present disclosure.

[0037] FIG. 2 shows a transmission electron microscopy (TEM) image of a composite loaded with magnesium hydride on two-dimensional transition metal carbide according to one embodiment of the present disclosure.

[0038] FIG. 3 shows a scanning electron microscopy (SEM) image of a composite loaded with magnesium hydride on two-dimensional transition metal carbide according to one embodiment of the present disclosure.

[0039] FIG. 4 shows particle size distribution of nano-magnesium hydride in a composite loaded with magnesium hydride on two-dimensional transition metal carbide according to one embodiment of the present disclosure.

[0040] FIG. 5 shows a temperature programmed desorption curve of a composite loaded with magnesium hydride on two-dimensional transition metal carbide according to one embodiment of the present disclosure.

[0041] FIG. 6 shows a cycle dehydrogenation curve of a composite loaded with magnesium hydride on two-dimensional transition metal carbide according to one embodiment of the present disclosure.

[0042] FIG. 7 shows a TEM image of a composite loaded with magnesium hydride on two-dimensional transition metal carbide according to one embodiment of the present disclosure.

[0043] FIG. 8 shows particle size distribution of nano-magnesium hydride in a composite loaded with magnesium hydride on two-dimensional transition metal carbide according to one embodiment of the present disclosure.

[0044] FIG. 9 shows a TEM image of a composite loaded with magnesium hydride on two-dimensional transition metal carbide according to one embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0045] Some preferred embodiments of the present disclosure will be introduced below with reference to the accompanying drawings, such that the technical contents could be understood clearly and easily. The present disclosure could be implemented by various embodiments, and the scope of the present disclosure is not limited to the embodiments mentioned herein.

[0046] A method for preparing a composite loaded with nano-magnesium hydride includes the following steps: [0047] step (1): adding a cationic surfactant into an aqueous dispersion of the two-dimensional transition metal carbide such that a nanosheet of a two-dimensional transition metal carbide wrinkles and aggregates, to obtain a first wrinkled two-dimensional transition metal carbide, followed by washing and drying the first wrinkled two-dimensional transition metal carbide to obtain a first dried product; [0048] step (2): placing the first dried product obtained from step (1) into a first sealed container, vacuuming the first sealed container, heating the first dried product to a first temperature of 600? C. to 1,000? C., and holding the first dried product at the first temperature for 2 h to 5 h to obtain a first heated product, and filling the first sealed container with 1 MPa to 10 MPa of pressurized hydrogen and holding the first heated product for 2 h to 5 h to obtain a first product; and [0049] step (3): adding the first product obtained from step (2) and dibutyl magnesium into an organic solvent to obtain a first mixture, subjecting the first mixture to ultrasonic dispersion to obtain a first dispersion mixture, heating the first dispersion mixture under stirring at a hydrogen pressure of 3 MPa to 6 MPa and a temperature of 180? C. to 220? C. for 12 h to 48 h to obtain a first heated dispersion mixture, followed by centrifuging and drying the first heated dispersion mixture to obtain the composite loaded with nano-magnesium hydride.

[0050] In some embodiments, the two-dimensional transition metal carbide in step (1) is any one selected from the group consisting of Ti.sub.3C.sub.2T.sub.x, Ti.sub.2CT.sub.x, V.sub.2CT.sub.x, Mo.sub.3C.sub.2T.sub.x, Nb.sub.2CT.sub.x, Nb.sub.4C.sub.3T.sub.x, Ta.sub.2CT.sub.x, and V.sub.4C.sub.3T.sub.x (T.sub.x refers to a surface chemical group, such as O.sup.2?, OH.sup.?, F.sup.?, NH.sub.3, NH.sup.4+).

[0051] In some embodiments, the cationic surfactant in step (1) is a nitrogen-containing organic amine derivative, preferably CTAB.

[0052] In some embodiments, in step (1), the cationic surfactant is dissolved in deionized water, and then added into the aqueous dispersion of the two-dimensional transition metal carbide under stirring.

[0053] In some embodiments, the sealed container in step (2) is a sealed stainless steel container.

[0054] In some embodiments, heating the first dried product to a first temperature in step (2) is conducted at a rate of 5? C./min to 10? C./min, and the first temperature after heating is 600? C., 700? C., 800? C., 900? C., or 1,000? C.

[0055] In some embodiments, the organic solvent in step (3) is selected from the group consisting of cyclohexane, hexane, heptane, and any mixture thereof.

[0056] In some embodiments, the ultrasonic dispersion in step (3) is conducted at a power of 200 W for 2 h.

[0057] In some embodiments, a mass ratio of the dibutyl magnesium to the two-dimensional transition metal carbide is adjusted so that a mass percentage of the magnesium hydride in the composite is in a range of 20% to 75%.

Example 1

[0058] Preparation of a composite 60 MgH.sub.2@Ti-MX1 loaded with nano-magnesium hydride on two-dimensional transition metal carbide: [0059] (1) 5 g of CTAB was dissolved in 100 ml of deionized water to obtain a CTAB solution; [0060] (2) the CTAB solution prepared in step (1) was added dropwise into 500 ml of a Ti.sub.3C.sub.2T.sub.x aqueous dispersion with a concentration of 2 mg/ml under stirring; a resulting mixture was centrifuged and washed 3 times, and a resulting centrifuged product was freeze-dried for 72 h to obtain a dried product; [0061] (3) the dried product obtained from step (2) was placed into a sealed stainless steel container, and the sealed stainless steel container was continuously vacuumed; after that, the dried product was heated to 800? C. at a rate of 5? C./min and held at 800? C. for 2 h; after that, the sealed stainless steel container was filled with 3 MPa of hydrogen and the resulting system was held for 2 h, and finally cooled to ambient temperature with the decrease of furnace temperature to obtain a product, denoted as Ti-MX1; [0062] (4) 30 mg of the Ti-MX1, 3.5 ml of a solution of dibutyl magnesium in heptane with a concentration of 0.5 M, and 40 ml of cyclohexane were added into a stainless steel autoclave with a polytetrafluoroethylene liner, and a resulting mixture was subjected to probing ultrasonic dispersion for 2 h at an ultrasonic power of 200 W to obtain a dispersion mixture; and [0063] (5) the stainless steel autoclave was filled with hydrogen to a pressure of 4.5 MPa; the dispersion mixture was heated to 200? C., and reacted under stirring for 12 h; after that, a resulting reaction product was centrifuged and dried to obtain the composite 60 MgH.sub.2@Ti-MX1 loaded with nano-magnesium hydride on two-dimensional transition metal carbide, with a magnesium hydride loading rate being 60 wt %.

[0064] An XRD pattern of the composite 60 MgH.sub.2@Ti-MX prepared in this example is shown in FIG. 1. As shown in FIG. 1, a phase of the composite is mainly composed of magnesium hydride and Ti-MX.

[0065] A TEM image of the composite 60 MgH.sub.2@Ti-MX prepared in this example is shown in FIG. 2, an SEM image of the composite 60 MgH.sub.2@Ti-MX prepared in this example is shown in FIG. 3, and particle size distribution of the composite 60 MgH.sub.2@Ti-MX prepared in this example is shown in FIG. 4. As shown in FIG. 2 to FIG. 4, the nanosheet of the two-dimensional transition metal carbide has wrinkles, and the nano-magnesium hydride is uniformly distributed on the surface of the two-dimensional transition metal carbide without obvious agglomeration and has an average particle size of 15 nm.

[0066] The composite 60 MgH.sub.2@Ti-MX1 prepared in this example was tested for its hydrogen storage performance:

[0067] FIG. 5 shows a temperature programmed desorption (TPD) curve of the composite 60 MgH.sub.2@Ti-MX1. As shown in FIG. 5, the composite 60 MgH.sub.2@Ti-MX1 has an initial hydrogen desorption temperature of 140? C. and a hydrogen storage capacity of 4.2 wt % H.sub.2.

[0068] FIG. 6 shows a cycle hydrogen desorption curve of the composite 60 MgH.sub.2@Ti-MX1 at 200? C. As shown in FIG. 6, the composite 60 MgH.sub.2@Ti-MX1 has an excellent cycle hydrogen absorption and desorption stability.

Example 2

[0069] Preparation of a composite 35 MgH.sub.2@Ti-MX2 loaded with nano-magnesium hydride on two-dimensional transition metal carbide: [0070] (1) 5 g of CTAB was dissolved in 100 ml of deionized water to obtain an CTAB solution; [0071] (2) the CTAB solution prepared in step (1) was added dropwise into 500 ml of a Ti.sub.3C.sub.2T.sub.x aqueous dispersion with a concentration of 2 mg/ml under stirring; a resulting mixture was centrifuged and washed 3 times, and a resulting centrifuged product was freeze-dried for 72 h to obtain a dried product; [0072] (3) the dried product obtained from step (2) was placed into a sealed stainless steel container, and the sealed stainless steel container was continuously vacuumed; after that, the dried product was heated to 600? C. at a rate of 5? C./min and held at 600? C. for 5 h; after that, the sealed stainless steel container was filled with 3 MPa of hydrogen, and the resulting system was held for 5 h, and finally cooled to ambient temperature with the decrease of furnace temperature to obtain a product, denoted as Ti-MX2; [0073] (4) 30 mg of the Ti-MX2, 1.3 ml of a solution of dibutyl magnesium in heptane with a concentration of 0.5 M, and 40 ml of cyclohexane were added into a stainless steel autoclave with a polytetrafluoroethylene liner, and a resulting mixture was subjected to probing ultrasonic dispersion for 2 h at an ultrasonic power of 200 W to obtain a dispersion mixture; and [0074] (5) the stainless steel autoclave was filled with hydrogen to a pressure of 3 MPa; the dispersion mixture was heated to 180? C., and reacted under stirring for 24 h; after that, a resulting reaction product was centrifuged and dried to obtain the composite 35 MgH.sub.2@Ti-MX2 loaded with nano-magnesium hydride on two-dimensional transition metal carbide, with a magnesium hydride loading rate being 35 wt %.

[0075] A TEM image of the composite 35 MgH.sub.2@Ti-MX2 prepared in this example is shown in in FIG. 7 and particle size distribution of the composite 35 MgH.sub.2@Ti-MX2 prepared in this example is shown in FIG. 8. As shown in FIG. 7 to FIG. 8, the nanosheet of the two-dimensional transition metal carbide has wrinkles, and the nano-magnesium hydride in the composite 35 MgH.sub.2@Ti-MX2 is uniformly distributed on the surface of the two-dimensional transition metal carbide, with an average particle size of about 8 nm.

Example 3

[0076] Preparation of a composite 60 MgH.sub.2@Ti-MX3 loaded with nano-magnesium hydride on two-dimensional transition metal carbide: [0077] (1) 1.5 g of acidified melamine was dissolved in 200 ml of deionized water to obtain a melamine solution; [0078] (2) the melamine solution prepared in step (1) was added dropwise into 500 ml of a Ti.sub.3C.sub.2T.sub.x aqueous dispersion with a concentration of 2 mg/ml under stirring; a resulting mixture was centrifuged and washed 3 times, and a resulting centrifuged product was freeze-dried for 72 h to obtain a dried product; [0079] (3) the dried product obtained from step (2) was placed into a sealed stainless steel container, and the sealed stainless steel container was continuously vacuumed; after that, the dried product was heated to 1,000? C. at a rate of 10? C./min and held at 1,000? C. for 3 h; after that, the sealed stainless steel container was filled with 4.5 MPa of hydrogen and the resulting system was held for 2 h, and finally cooled to ambient temperature with the decrease of furnace temperature to obtain a product, denoted as Ti-MX3; [0080] (4) 30 mg of the Ti-MX3, 3.5 ml of a solution of dibutyl magnesium in heptane with a concentration of 0.5M, and 40 ml of cyclohexane were added into a stainless steel autoclave with a polytetrafluoroethylene liner, and a resulting mixture was subjected to probing ultrasonic dispersion for 2 h at an ultrasonic power of 200 W to obtain a dispersion mixture; and [0081] (5) the stainless steel autoclave was filled with hydrogen to a pressure of 6 MPa; the dispersion mixture was heated to 220? C., and reacted under stirring for 12 h; after that, a resulting reaction product was centrifuged and dried to obtain the composite 60 MgH.sub.2@Ti-MX3 loaded with nano-magnesium hydride on two-dimensional transition metal carbide, with a magnesium hydride loading rate being 60 wt %.

[0082] A TEM image of the composite 60 MgH.sub.2@Ti-MX3 prepared in this example is shown in FIG. 9. As shown in FIG. 9, the nanosheet of the two-dimensional transition metal carbide has wrinkles, and the nano-magnesium hydride in the composite 60 MgH.sub.2@Ti-MX3 is uniformly distributed on the surface of the two-dimensional transition metal carbide, with an average particle size of about 17 nm.

[0083] The foregoing is detailed description of the preferred specific embodiments of the present disclosure. It should be understood that for a person of ordinary skill in the art, various modifications and variations could be made according to the concept of the present disclosure without creative efforts. Therefore, all technical solutions that could be made by a person skilled in the art based on the prior art through logical analysis, reasoning, or finite experiments according to the concept of the present disclosure shall fall within the scope defined by the appended claims.