MXene / NiMn-LDHs hybrid electrocatalyst and preparation method thereof
Through the preparation of MXene/NiMn-LDHs hybrid electrocatalyst, the problems of high cost of precious metal catalysts and insufficient performance of non-precious metal catalysts are solved, and efficient and stable electrolytic water catalysis is achieved, with wide application prospects.
Patent Information
- Application Number
- CN202411343584.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-25
- Publication Date
- 2024-12-31
AI Technical Summary
The existing precious metal catalysts have high costs, shortage of supply, poor stability, poor conductivity of non-precious metal catalysts and insufficient exposure of active sites, resulting in insufficient catalytic performance of electrolytic water.
Using the preparation method of MXene/NiMn-LDHs hybrid electrocatalyst, by mixing Ti3AlC2 powder with fluoride salt, hydrochloric acid etching and hydrothermal reaction, Ni and Mn elements were introduced, and liquid phase shearing and hydrothermal heat were used. The reaction forms MXene/NiMn-LDHs hybrid, improving its electrocatalytic properties.
It realizes a low-cost and simple preparation process, improves the electrochemical activity and catalytic performance of NiMn-LDHs, reduces the overpotential, improves the energy conversion efficiency, has good stability and wide application prospects, and can replace precious metal catalysts.
Smart Images
Figure CN119221012A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of electrocatalysts, and in particular relates to a MXene / NiMn-LDHs hybrid electrocatalyst and a preparation method thereof. Background Art
[0002] Electrochemical water splitting is becoming increasingly important in the development of green energy and environmental protection. However, the kinetics of the water splitting reaction are slow, especially for the four-electron (4e - ) transfer process, therefore, excellent electrocatalysts are usually required to accelerate the reaction, reduce the overpotential, and improve the energy conversion efficiency. Currently, noble metal oxides (such as RuO2 and IrO2) show good OER performance, but their high cost, supply shortage and poor electrochemical stability hinder their large-scale application. In addition, these noble metal-based catalysts lack good conductivity and may undergo oxidation to form high-valent oxides (such as RuO4 and IrO3) during the electrolysis of water in alkaline electrolytes. Therefore, in recent years, the exploration of highly active, highly stable and noble metal-free electrocatalysts has attracted great attention.
[0003] So far, a large number of non-precious metal catalysts have been developed, such as perovskites, spinels, layered oxides, and other metal oxides. Among these electrocatalysts, layered double hydroxides (LDHs) are typical non-precious metal hydrotalcite clay materials and a class of structurally similar layered bimetallic compounds. They are considered to be a promising candidate for non-precious metal OER electrocatalysts due to their compositional and structural flexibility, simple preparation methods, and unique physicochemical properties. In particular, nickel-based LDHs, such as NiFe-LDH, NiCo-LDH, and NiMn-LDHs, have been widely studied. However, their poor conductivity, insufficient exposure of active sites, and limited electrochemically active surface area (ECSA) have seriously hindered their further improvement of electrocatalytic OER performance and practical applications.
[0004] In view of the high cost, supply shortage, and poor stability of existing precious metal catalysts, and the poor conductivity, insufficient exposure of active sites, and limited electrochemical active surface area of non-precious metal catalysts, there is an urgent need to find a more economical and convenient method to prepare the catalysts needed for water electrolysis. Summary of the invention
[0005] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a MXene / NiMn-LDHs hybrid electrocatalyst and a preparation method thereof, so as to solve the technical problems of high cost, complex preparation and insufficient electrocatalytic performance of the existing water electrolysis catalysts.
[0006] In order to achieve the above object, the present invention adopts the following technical solutions:
[0007] The present invention discloses a method for preparing a MXene / NiMn-LDHs hybrid electrocatalyst, comprising the following steps:
[0008] 1) fully mixing Ti3AlC2 powder and fluoride salt to obtain a first mixture;
[0009] 2) mixing the first mixture with a hydrochloric acid solution, stirring for reaction, washing with water, and vacuum drying to obtain a first powder;
[0010] 3) mixing the first powder with the first portion of NiCl2·6H2O and MnCl2·4H2O to obtain a second mixture, mixing the second mixture with deionized water to obtain a first mixed solution, and mixing the first mixed solution with an N-methylpyrrolidone solution to obtain a second mixed solution;
[0011] 4) After liquid phase shearing of the second mixed solution, it is mixed with the second portion of NiCl2·6H2O and hexamethylenetetramine, and after hydrothermal reaction, a third mixture is obtained; the third mixture is washed with water, washed with alcohol and freeze-dried to obtain a MXene / NiMn-LDHs hybrid electrocatalyst.
[0012] Preferably, in step 1), the molar ratio of Ti3AlC2 powder to fluoride salt is 1:(1-2); the fluoride salt is any one of sodium fluoride, lithium fluoride and ammonium fluoride.
[0013] Preferably, in step 2), the solid-liquid ratio of the first mixture to the hydrochloric acid solution is (0.015-0.055) g:1 mL; and the molar concentration of the hydrochloric acid solution is 5.57-10.05 mol / L.
[0014] Preferably, in step 2), the stirring reaction time is 12.5-23.5 h; the stirring reaction temperature is 40-55°C.
[0015] Preferably, in step 3), the mass ratio of the first powder, the first portion of NiCl2·6H2O and MnCl2·4H2O is 1:(0.5-1.2):(0.5-1.2).
[0016] Preferably, in step 3), the solid-liquid ratio of the second mixture to deionized water is (0.012-0.021) g:1 mL; and the volume ratio of the first mixed solution to the N-methylpyrrolidone solution is 1:(0.15-0.23).
[0017] Preferably, in step 4), the time for liquid phase shearing of the second mixed solution is 6.5-11.5 hours.
[0018] Preferably, in step 4), the molar ratio of the second portion of NiCl2·6H2O to hexamethylenetetramine is 1:(0.6-1).
[0019] Preferably, in step 4), the temperature of the hydrothermal reaction is 120-140° C., and the time of the hydrothermal reaction is 3-8 h.
[0020] The present invention also discloses a MXene / NiMn-LDHs hybrid electrocatalyst, which is prepared by the above preparation method.
[0021] Compared with the prior art, the present invention has the following beneficial effects:
[0022] The invention discloses a method for preparing a MXene / NiMn-LDHs hybrid electrocatalyst, wherein Ti3AlC2 powder is fully mixed with a fluoride salt to ensure uniform contact between the etchant and the raw material, thereby laying a solid foundation for the subsequent preparation of MXene. The removal of the Al layer is further promoted by the etching action of a hydrochloric acid solution, and the MXene layer is effectively peeled off by acting together with the fluoride salt. The MXene powder is mixed with NiCl2·6H2O and MnCl2·4H2O, and the key elements Ni and Mn constituting NiMn-LDHs are successfully introduced. At the same time, the addition of N-methylpyrrolidone improves the dispersibility and stability of the mixture, thereby creating more favorable conditions for the subsequent hydrothermal reaction and the formation of NiMn-LDHs. The mixture is further dispersed and homogenized by liquid phase shearing, so that the Ni and Mn elements are more evenly distributed on the surface of the MXene. It is then mixed with NiCl2·6H2O and hexamethylenetetramine and subjected to a hydrothermal reaction, which promotes the growth of NiMn-LDHs on the surface of MXene; ultimately, a MXene / NiMn-LDHs hybrid electrocatalyst with excellent electrocatalytic performance is obtained. The present invention explores a more economical and convenient method for preparing a catalyst required for water electrolysis. A low-cost preparation process is used to prepare a MXene / NiMn-LDHs hybrid electrocatalyst, which effectively enhances the electrochemical activity of NiMn-LDHs and improves its electrocatalytic performance. The NiFe-LDH material based on Ni and Fe elements can be mass-produced because of its relatively low preparation price and its strong ability to catalyze the electrolysis of water in an alkaline environment. It is expected to be used to replace expensive precious metal catalysts and has good application prospects.
[0023] The present invention also discloses a MXene / NiMn-LDHs hybrid electrocatalyst prepared by the above-mentioned preparation method. Due to the high conductivity of MXene and the catalytic activity of NiMn-LDHs, the hybrid electrocatalyst exhibits excellent electrocatalytic performance in reactions such as electrolysis of water, which helps to reduce overpotential and improve energy conversion efficiency. The hybrid structure of MXene and NiMn-LDHs enhances the stability of the catalyst, so that it can maintain catalytic activity for a long time in practical applications and reduce performance degradation. The use of low-cost raw materials and simple preparation processes greatly reduces the preparation cost of the electrocatalyst, and is expected to replace expensive precious metal catalysts and promote the economic development of green energy and environmental protection. The preparation process is simple and highly repeatable, so that the electrocatalyst is easy to achieve large-scale production and meet the needs of practical applications. It is not only suitable for the field of electrolysis of water, but also expected to play an important role in other chemical reactions requiring electrocatalysis, showing a wide range of application prospects. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 This is a SEM image of the MXene / NiMn-LDHs hybrid electrocatalyst prepared in Example 2 of the present invention. DETAILED DESCRIPTION
[0025] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.
[0026] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.
[0027] The present invention is further described in detail below in conjunction with the accompanying drawings:
[0028] The present invention discloses a method for preparing a MXene / NiMn-LDHs hybrid electrocatalyst, comprising the following steps:
[0029] 1) fully mixing Ti3AlC2 powder and fluoride salt in a certain molar ratio to obtain a first mixture;
[0030] 2) mixing the first mixture with a hydrochloric acid solution of a certain molar concentration at a certain solid-liquid ratio, stirring at a certain temperature for a certain time, washing with water, and vacuum drying to obtain a first powder;
[0031] 3) mixing the first powder with the first portion of NiCl2·6H2O and MnCl2·4H2O in a certain mass ratio to obtain a second mixture, mixing the second mixture with deionized water in a certain solid-liquid ratio to obtain a first mixed solution, and mixing the first mixed solution with an N-methylpyrrolidone solution in a certain volume ratio to obtain a second mixed solution;
[0032] 4) After the second mixed solution is subjected to liquid phase shearing for a certain period of time, it is transferred to a reaction kettle, and hexamethylenetetramine is added to the second portion of NiCl2·6H2O at a certain molar ratio, and a third mixture is obtained after a hydrothermal reaction at a certain temperature for a certain period of time;
[0033] 5) The third mixture is washed with water, washed with alcohol, and freeze-dried to obtain a MXene / NiMn-LDHs hybrid.
[0034] Wherein, in step 1), the molar ratio of Ti3AlC2 powder to fluoride salt is 1:(1-2).
[0035] The fluoride salt is any one of sodium fluoride, lithium fluoride and ammonium fluoride.
[0036] In step 2), the solid-to-liquid ratio of the first mixture to the hydrochloric acid solution is 0.015-0.055 g / mL.
[0037] The molar concentration of the hydrochloric acid solution is 5.57-10.05 mol / L.
[0038] The stirring time is 12.5-23.5h; the stirring temperature is 40-55℃.
[0039] In step 4), the mass ratio of the first powder, the first portion of NiCl2·6H2O and MnCl2·4H2O is 1:(0.5-1.2):(0.5-1.2).
[0040] The solid-to-liquid ratio of the second mixture to deionized water is 0.012 g / mL-0.021 g / mL.
[0041] The volume ratio of the first mixed solution to the N-methylpyrrolidone solution is 1:(0.15-0.23).
[0042] The second mixed solution is subjected to liquid phase shearing for 6.5-11.5 hours.
[0043] The molar ratio of the second portion of NiCl2·6H2O to hexamethylenetetramine is 1:0.6-1:1.
[0044] The hydrothermal temperature is 120-140°C and the hydrothermal time is 3-8h.
[0045] The present invention discloses a method for preparing a MXene / NiMn-LDHs hybrid electrocatalyst, wherein Ti3AlC2 powder is fully mixed with a fluoride salt to obtain a first mixture; this step is to prepare a precursor for MXene. Fluoride salt is used as an etchant, and after mixing with Ti3AlC2 powder, it can effectively etch away the Al layer in the subsequent steps to obtain MXene, and sufficient mixing ensures the uniformity of etching. The first mixture is mixed with a hydrochloric acid solution, stirred for reaction, washed with water, and vacuum dried to obtain a first powder; the hydrochloric acid solution further promotes the etching of the Al layer, and works together with the fluoride salt to peel off the MXene layer. Water washing removes residual etchants and impurities, and vacuum drying ensures the dryness of the powder, providing a good raw material for subsequent steps. The first powder is mixed with the first portion of NiCl2·6H2O and MnCl2·4H2O to obtain a second mixture, the second mixture is mixed with deionized water to obtain a first mixed solution, and the first mixed solution is mixed with N-methylpyrrolidone solution to obtain a second mixed solution; this step introduces Ni and Mn elements, which are key components of NiMn-LDHs. N-methylpyrrolidone as a solvent helps to improve the dispersibility and stability of the mixture, providing good conditions for the subsequent hydrothermal reaction. After the second mixed solution is subjected to liquid phase shearing, it is mixed with the second portion of NiCl2·6H2O and hexamethylenetetramine, and after hydrothermal reaction, a third mixture is obtained; the third mixture is washed with water, washed with alcohol and freeze-dried to obtain a MXene / NiMn-LDHs hybrid electrocatalyst. Liquid phase shearing helps to further disperse and homogenize the mixture, so that the Ni and Mn elements are more evenly distributed on the MXene surface. Hexamethylenetetramine as an alkali source promotes the formation of NiMn-LDHs. The hydrothermal reaction is the key step in the growth of NiMn-LDHs, which deposits Ni and Mn elements on the MXene surface in the form of LDHs. Water washing and alcohol washing remove residual impurities and unreacted raw materials, and freeze drying retains the structure and properties of the hybrid, ultimately obtaining a MXene / NiMn-LDHs hybrid electrocatalyst with excellent electrocatalytic performance.
[0046] The present invention also discloses a MXene / NiMn-LDHs hybrid electrocatalyst prepared by the above preparation method. The MXene-loaded NiMn-LDHs is used as a high-efficiency electrocatalyst for enhancing the oxygen evolution reaction, and the suspension can be fully reacted to obtain the MXene / NiMn-LDHs hybrid electrocatalyst. The prepared MXene / NiMn-LDHs hybrid electrocatalyst has excellent electrocatalytic performance, and the material preparation cost is low, and mass production can be achieved, and it can be applied to the field of electrocatalysts.
[0047] Furthermore, Ti3C2 nanosheets used as the substrate for preparing composite materials by in-situ growth method should not only have uniform size but also uniform thickness.
[0048] See also Figure 1 This is an SEM image of the MXene / NiMn-LDHs hybrid electrocatalyst prepared in Example 2 of the present invention; it can be observed that NiMn-LDHs grow uniformly on the lamellar MXene surface, indicating the successful preparation of the NiMn-LDHs / MXene hybrid.
[0049] Example 1
[0050] This embodiment provides a method for preparing a MXene / NiMn-LDHs hybrid electrocatalyst, which comprises the following steps:
[0051] 1) 3 g of 15.4 mmol Ti3AlC2 powder and 0.8008 g of 30.8 mmol LiF were mixed in a molar ratio of 1:2 to obtain a first mixture of 3.8008 g.
[0052] 2) The first mixture was mixed with 69.105 mL of 10.05 mol / L hydrochloric acid solution at a solid-liquid ratio of 0.055 g / mL, stirred at 55° C. for 23.5 h, and 1.5 g of MXene first powder was obtained after washing with water and vacuum drying.
[0053] 3) The first powder was mixed with 1.8 g of the first NiCl2·6H2O and 1.8 g of MnCl2·4H2O in a mass ratio of 1:1.2:1.2 to obtain a second mixture, the second mixture was mixed with 242.875 mL of deionized water at a solid-liquid ratio of 0.021 g / mL to obtain a first mixed solution, and the first mixed solution was mixed with 55.861 mL of N-methylpyrrolidone at a volume ratio of 1:0.23 to obtain a second mixed solution.
[0054] 4) After the second mixed solution was subjected to liquid phase shearing for 11.5 h, it was transferred to a reactor, and 4.5378 mmol of hexamethylenetetramine was added to 1.8 g (7.563 mmol) of the second portion of NiCl2·6H2O at a molar ratio of 1:0.6, and hydrothermally reacted at 140° C. for 8 h to obtain a third mixture.
[0055] 5) The third mixture is washed with water, washed with alcohol, and freeze-dried to obtain a MXene / NiMn-LDHs hybrid electrocatalyst.
[0056] Example 2
[0057] This embodiment provides a method for preparing a MXene / NiMn-LDHs hybrid electrocatalyst, which comprises the following steps:
[0058] 1) 3 g of 15.4 mmol Ti3AlC2 powder and 1.2936 g of 30.8 mmol NaF were mixed in a molar ratio of 1:2 to obtain a first mixture of 4.2936 g.
[0059] 2) The first mixture was mixed with 78.065 mL of 10.05 mol / L hydrochloric acid solution at a solid-liquid ratio of 0.055 g / mL, stirred at 55° C. for 23.5 h, and 1.5 g of MXene first powder was obtained after washing with water and vacuum drying.
[0060] 3) The first powder was mixed with 1.8 g of the first NiCl2·6H2O and 1.8 g of MnCl2·4H2O in a mass ratio of 1:1.2:1.2 to obtain a second mixture, the second mixture was mixed with 242.875 mL of deionized water at a solid-liquid ratio of 0.021 g / mL to obtain a first mixed solution, and the first mixed solution was mixed with 55.861 mL of N-methylpyrrolidone at a volume ratio of 1:0.23 to obtain a second mixed solution.
[0061] 4) After the second mixed solution was subjected to liquid phase shearing for 11.5 h, it was transferred to a reactor, and 4.5378 mmol of hexamethylenetetramine was added to 1.8 g (7.563 mmol) of the second portion of NiCl2·6H2O at a molar ratio of 1:0.6, and hydrothermally reacted at 140° C. for 8 h to obtain a third mixture.
[0062] 5) The third mixture is washed with water, washed with alcohol, and freeze-dried to obtain a MXene / NiMn-LDHs hybrid electrocatalyst.
[0063] Example 3
[0064] This embodiment provides a method for preparing a MXene / NiMn-LDHs hybrid electrocatalyst, which comprises the following steps:
[0065] 1) 0.5 g of 2.6 mmol Ti3AlC2 powder and 0.096 g of 2.6 mmol NH4F were mixed in a molar ratio of 1:1 to obtain a first mixture of 0.596 g.
[0066] 2) The first mixture was mixed with 39.754 mL of 5.57 mol / L hydrochloric acid solution at a solid-liquid ratio of 0.015 g / mL, stirred at 40° C. for 12.5 h, and 0.25 g of MXene first powder was obtained after washing with water and vacuum drying.
[0067] 3) The first powder was mixed with 0.125 g of the first NiCl2·6H2O and 0.125 g of MnCl2·4H2O in a mass ratio of 1:0.5:0.5 to obtain a second mixture, the second mixture was mixed with 41.667 mL of deionized water at a solid-liquid ratio of 0.012 g / mL to obtain a first mixed solution, and the first mixed solution was mixed with 6.25 mL of N-methylpyrrolidone in a volume ratio of 1:0.15 to obtain a second mixed solution.
[0068] 4) After the second mixed solution was subjected to liquid phase shearing for 6.5 h, it was transferred to a reactor, and 0.527 mmol of hexamethylenetetramine was added to 0.125 g 0.527 mmol of the second portion of NiCl2·6H2O at a molar ratio of 1:1, and hydrothermally reacted at 120° C. for 3 h to obtain a third mixture.
[0069] 5) The third mixture is washed with water, washed with alcohol, and freeze-dried to obtain a MXene / NiMn-LDHs hybrid electrocatalyst.
[0070] Example 4
[0071] This embodiment provides a method for preparing a MXene / NiMn-LDHs hybrid electrocatalyst, which comprises the following steps:
[0072] 1) 0.5 g of 2.6 mmol Ti3AlC2 powder and 0.109 g of 2.6 mmol NaF were fully mixed in a molar ratio of 1:1 to obtain a first mixture of 0.609 g.
[0073] 2) The first mixture was mixed with 40.611 mL of 5.57 mol / L hydrochloric acid solution at a solid-liquid ratio of 0.015 g / mL, stirred at 40° C. for 12.5 h, and 0.25 g of MXene first powder was obtained after washing with water and vacuum drying.
[0074] 3) The first powder was mixed with 0.125 g of the first NiCl2·6H2O and 0.125 g of MnCl2·4H2O in a mass ratio of 1:0.5:0.5 to obtain a second mixture, the second mixture was mixed with 41.667 mL of deionized water at a solid-liquid ratio of 0.012 g / mL to obtain a first mixed solution, and the first mixed solution was mixed with 6.25 mL of N-methylpyrrolidone in a volume ratio of 1:0.15 to obtain a second mixed solution.
[0075] 4) After the second mixed solution was subjected to liquid phase shearing for 6.5 h, it was transferred to a reactor, and 0.527 mmol of hexamethylenetetramine was added to 0.125 g 0.527 mmol of the second portion of NiCl2·6H2O at a molar ratio of 1:1, and hydrothermally reacted at 120° C. for 3 h to obtain a third mixture.
[0076] 5) The third mixture is washed with water, washed with alcohol, and freeze-dried to obtain a MXene / NiMn-LDHs hybrid electrocatalyst.
[0077] Example 5
[0078] This embodiment provides a method for preparing a MXene / NiMn-LDHs hybrid electrocatalyst, which comprises the following steps:
[0079] 1) 1 g of 5.2 mmol Ti3AlC2 powder and 0.273 g of 6.5 mmol NaF were mixed at a molar ratio of 1:1.25 to obtain a first mixture of 1.273 g.
[0080] 2) The first mixture was mixed with 63.65 mL of 7.05 mol / L hydrochloric acid solution at a solid-liquid ratio of 0.02 g / mL, stirred at 45 °C for 16 h, and 0.5 g of MXene first powder was obtained after washing with water and vacuum drying.
[0081] 3) The first powder was mixed with 0.35 g of the first NiCl2·6H2O and 0.35 g of MnCl2·4H2O in a mass ratio of 1:0.7:0.7 to obtain a second mixture, the second mixture was mixed with 80 mL of deionized water at a solid-liquid ratio of 0.015 g / mL to obtain a first mixed solution, and the first mixed solution was mixed with 13.6 mL of N-methylpyrrolidone in a volume ratio of 1:0.17 to obtain a second mixed solution.
[0082] 4) After the second mixed solution was subjected to liquid phase shearing for 7 h, it was transferred to a reaction kettle, and 1.323 mmol of hexamethylenetetramine was added to 0.35 g (1.47 mmol) of the second portion of NiCl2·6H2O at a molar ratio of 1:0.9, and hydrothermally reacted at 125° C. for 4 h to obtain a third mixture.
[0083] 5) The third mixture is washed with water, washed with alcohol, and freeze-dried to obtain a MXene / NiMn-LDHs hybrid electrocatalyst.
[0084] Example 6
[0085] This embodiment provides a method for preparing a MXene / NiMn-LDHs hybrid electrocatalyst, which comprises the following steps:
[0086] 1) 1 g of 5.2 mmol Ti3AlC2 powder and 0.169 g of 6.5 mmol NaF were mixed at a molar ratio of 1:1.25 to obtain a first mixture of 1.169 g.
[0087] 2) The first mixture was mixed with 58.45 mL of 7.05 mol / L hydrochloric acid solution at a solid-liquid ratio of 0.02 g / mL, stirred at 45 °C for 16 h, and 0.5 g of MXene first powder was obtained after washing with water and vacuum drying.
[0088] 3) The first powder was mixed with 0.35 g of the first NiCl2·6H2O and 0.35 g of MnCl2·4H2O in a mass ratio of 1:0.7:0.7 to obtain a second mixture, the second mixture was mixed with 80 mL of deionized water at a solid-liquid ratio of 0.015 g / mL to obtain a first mixed solution, and the first mixed solution was mixed with 13.6 mL of N-methylpyrrolidone in a volume ratio of 1:0.17 to obtain a second mixed solution.
[0089] 4) After the second mixed solution was subjected to liquid phase shearing for 7 h, it was transferred to a reaction kettle, and 1.47 mmol hexamethylenetetramine was added with 0.35 g 1.47 mmol second portion of NiCl2·6H2O at a molar ratio of 1:1, and hydrothermally reacted at 135° C. for 5 h to obtain a third mixture.
[0090] 5) The third mixture is washed with water, washed with alcohol, and freeze-dried to obtain a MXene / NiMn-LDHs hybrid electrocatalyst.
[0091] Example 7
[0092] This embodiment provides a method for preparing a MXene / NiMn-LDHs hybrid electrocatalyst, which comprises the following steps:
[0093] 1) 2 g 7.6 mmol Ti3AlC2 powder and 0.5568 g 13.3 mmol NaF were mixed at a molar ratio of 1:1.75 to obtain a first mixture of 2.5568 g.
[0094] 2) The first mixture was mixed with 56.82 mL of 8.5 mol / L hydrochloric acid solution at a solid-liquid ratio of 0.045 g / mL, stirred at 50° C. for 20 h, and 1 g of MXene first powder was obtained after washing with water and vacuum drying.
[0095] 3) The first powder was mixed with 1.1 g of the first NiCl2·6H2O and 1.1 g of MnCl2·4H2O in a mass ratio of 1:1.1:1.1 to obtain a second mixture, the second mixture was mixed with 168.42 mL of deionized water at a solid-liquid ratio of 0.019 g / mL to obtain a first mixed solution, and the first mixed solution was mixed with 35.37 mL of N-methylpyrrolidone at a volume ratio of 1:0.21 to obtain a second mixed solution.
[0096] 4) After the second mixed solution was subjected to liquid phase shearing for 9.5 h, it was transferred to a reaction kettle, and 3.24 mmol of hexamethylenetetramine was added to 1.1 g (4.63 mmol) of the second portion of NiCl2·6H2O at a molar ratio of 1:0.7, and hydrothermally reacted at 135° C. for 5.5 h to obtain a third mixture.
[0097] 5) The third mixture is washed with water, washed with alcohol, and freeze-dried to obtain a MXene / NiMn-LDHs hybrid electrocatalyst.
[0098] Example 8
[0099] This embodiment provides a method for preparing a MXene / NiMn-LDHs hybrid electrocatalyst, which comprises the following steps:
[0100] 1) 2 g (7.6 mmol) of Ti3AlC2 powder and 0.4921 g (13.3 mmol) of NH4F were mixed at a molar ratio of 1:1.75 to obtain a first mixture weighing 2.4921 g in total.
[0101] 2) The first mixture was mixed with 55.38 mL of 8.5 mol / L hydrochloric acid solution at a solid-liquid ratio of 0.045 g / mL, stirred at 50° C. for 20 h, and 1 g of MXene first powder was obtained after washing with water and vacuum drying.
[0102] 3) The first powder was mixed with 1.1 g of the first NiCl2·6H2O and 1.1 g of MnCl2·4H2O in a mass ratio of 1:1.1:1.1 to obtain a second mixture, the second mixture was mixed with 168.42 mL of deionized water at a solid-liquid ratio of 0.019 g / mL to obtain a first mixed solution, and the first mixed solution was mixed with 35.37 mL of N-methylpyrrolidone at a volume ratio of 1:0.21 to obtain a second mixed solution.
[0103] 4) After the second mixed solution was subjected to liquid phase shearing for 9.5 h, it was transferred to a reaction kettle, and 3.24 mmol of hexamethylenetetramine was added to 1.1 g (4.63 mmol) of the second portion of NiCl2·6H2O at a molar ratio of 1:0.7, and hydrothermally reacted at 135° C. for 5.5 h to obtain a third mixture.
[0104] 5) The third mixture is washed with water, washed with alcohol, and freeze-dried to obtain a MXene / NiMn-LDHs hybrid electrocatalyst.
[0105] The above contents are only for explaining the technical idea of the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.
Claims
1. A method for preparing a MXene / NiMn-LDHs hybrid electrocatalyst, characterized in that: The following steps are involved: 1) fully mixing Ti3AlC2 powder and fluoride salt to obtain a first mixture; 2) mixing the first mixture with a hydrochloric acid solution, stirring for reaction, washing with water, and vacuum drying to obtain a first powder; 3) mixing the first powder with the first portion of NiCl2·6H2O and MnCl2·4H2O to obtain a second mixture, mixing the second mixture with deionized water to obtain a first mixed solution, and mixing the first mixed solution with an N-methylpyrrolidone solution to obtain a second mixed solution; 4) After liquid phase shearing of the second mixed solution, it is mixed with the second portion of NiCl2·6H2O and hexamethylenetetramine, and after hydrothermal reaction, a third mixture is obtained; the third mixture is washed with water, washed with alcohol and freeze-dried to obtain a MXene / NiMn-LDHs hybrid electrocatalyst.
2. The method for preparing the MXene / NiMn-LDHs hybrid electrocatalyst according to claim 1, characterized in that: In step 1), the molar ratio of the Ti3AlC2 powder to the fluoride salt is 1:(1-2); the fluoride salt is any one of sodium fluoride, lithium fluoride and ammonium fluoride.
3. The method for preparing the MXene / NiMn-LDHs hybrid electrocatalyst according to claim 1, characterized in that: In step 2), the solid-to-liquid ratio of the first mixture to the hydrochloric acid solution is (0.015-0.055) g:1 mL; the molar concentration of the hydrochloric acid solution is 5.57-10.05 mol / L.
4. The method for preparing the MXene / NiMn-LDHs hybrid electrocatalyst according to claim 1, characterized in that: In step 2), the stirring reaction time is 12.5-23.5 hours; the stirring reaction temperature is 40-55°C.
5. The method for preparing the MXene / NiMn-LDHs hybrid electrocatalyst according to claim 1, characterized in that: In step 3), the mass ratio of the first powder, the first portion of NiCl2·6H2O and MnCl2·4H2O is 1:(0.5-1.2):(0.5-1.2).
6. The method for preparing the MXene / NiMn-LDHs hybrid electrocatalyst according to claim 1, characterized in that: In step 3), the solid-liquid ratio of the second mixture to deionized water is (0.012-0.021) g:1 mL; the volume ratio of the first mixed solution to the N-methylpyrrolidone solution is 1:(0.15-0.23).
7. The method for preparing the MXene / NiMn-LDHs hybrid electrocatalyst according to claim 1, characterized in that: In step 4), the second mixed solution is subjected to liquid phase shearing for 6.5-11.5 hours.
8. The method for preparing the MXene / NiMn-LDHs hybrid electrocatalyst according to claim 1, characterized in that: In step 4), the molar ratio of the second portion of NiCl2·6H2O to hexamethylenetetramine is 1:(0.6-1).
9. The method for preparing the MXene / NiMn-LDHs hybrid electrocatalyst according to claim 1, characterized in that: In step 4), the temperature of the hydrothermal reaction is 120-140° C., and the time of the hydrothermal reaction is 3-8 hours.
10. A MXene / NiMn-LDHs hybrid electrocatalyst, characterized in that: The method is prepared by any one of claims 1 to 9.