Sea urchin-like nickel / titanium-based catalyst, preparation method thereof and application of catalyst in magnesium hydride hydrogen storage

Abstract

The invention discloses an urchin-like nickel / titanium-based catalyst, a preparation method thereof and application of the catalyst in magnesium hydride hydrogen storage, and belongs to the technical field of hydrogen storage materials. The catalyst is composed of two phases of NiS and TiO2, the TiO2 is dispersed inside and on the surface of a NiS framework, the whole catalyst is in a sea urchin shape, and the preparation method of the catalyst comprises the following steps that firstly, nickel, titanium and aluminum metal elementary substances are smelted into nickel-titanium-aluminum alloy; then, a sodium hydroxide solution is adopted for conducting dealloying treatment on the alloy powder, and a porous nickel-titanium solid solution is obtained; then, the porous nickel-titanium solid solution powder, CH4N2S and NH4Cl are added into deionized water together, and hydrothermal treatment is carried out; and finally, filtering the hydrothermal treatment product, and washing and drying the solid filter to obtain the product. The preparation method is wide in raw material source, simple in process, safe, reliable and easy for large-scale production. The prepared catalyst is mechanically mixed with magnesium hydride, so that the hydrogen desorption temperature of the magnesium hydride can be obviously reduced, and the catalyst has good cycle stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogen storage materials, and in particular relates to a sea urchin-like nickel / titanium-based catalyst, a preparation method thereof, and application thereof in magnesium hydride hydrogen storage. Background Art

[0002] Hydrogen energy is a clean secondary energy source with high calorific value, abundant resources and sustainable development. How to achieve safe and efficient storage of hydrogen is the key to promoting the development of the hydrogen energy industry. Compared with high-pressure gaseous and deep-cold liquid hydrogen storage methods, solid-state hydrogen storage can be carried out under mild conditions and has the advantages of high hydrogen storage density and safety and reliability. Magnesium hydride (MgH2), as a typical representative of metal hydride hydrogen storage materials, has high hydrogen storage capacity, low cost and environmental friendliness, and has attracted much attention in solid-state hydrogen storage technology. However, due to its high thermodynamic stability and poor kinetic characteristics, MgH2 has shortcomings such as high hydrogen desorption temperature, slow hydrogen absorption and desorption rate and poor cyclic stability, which greatly limit its large-scale application.

[0003] Catalyst doping is one of the important methods to improve the hydrogen storage performance of MgH2. Among many transition metal-based catalysts, nickel / titanium-based catalysts have been widely proven to have good effects. For example, Zeng et al. prepared a Ni and TiO2 co-doped reduced graphene oxide ((Ni-TiO2)@rGO), which reduced the hydrogen desorption and absorption temperatures of MgH2 to 479 and 323K, respectively [Liang Zeng, Peilin Qing, Fangfang Cai, et al, Frontiers in Chemistry, 2020, 8: 207]. Zhu et al. added nano-Ni to Ti3C2T x MXene nanosheet catalyst (Ni / Ti3C2) is used for Mg absorption and desorption of hydrogen. The system can release 3.96 wt.% of hydrogen at 300°C and exhibits good cyclic stability [Xunqin Zhu, Minjian Yang, Dengfei Mu, et al, ACS Applied Nano Materials, 2023, 6(23): 21521]. However, although the catalyst provided by the above technical solution has a certain effect on improving the hydrogen absorption and desorption performance of MgH2, the preparation process is complicated, the cost is high, and it is difficult to mass produce. It cannot meet the requirements of practical applications for high performance, low cost, and easy scalability.

[0004] In summary, the development of a nickel / titanium-based catalyst with simple preparation process, low cost and good catalytic performance is of great significance for the practical application of MgH2 solid-state hydrogen storage. Summary of the Invention

[0005] In response to the shortcomings of existing MgH2 hydrogen absorption and desorption catalyst technology and MgH2 hydrogen storage technology, the present invention provides a sea urchin-shaped nickel / titanium-based catalyst and its preparation method with simple preparation process, safety, reliability and low cost. The catalyst is applied to MgH2 hydrogen storage, which can significantly reduce the hydrogen desorption temperature of MgH2 and improve the cyclic stability of hydrogen absorption and desorption.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] The sea urchin-like nickel / titanium-based catalyst provided by the present invention is composed of two phases, NiS and TiO2, and TiO2 is dispersed inside and on the surface of the NiS skeleton, and the whole catalyst is sea urchin-like.

[0008] The present invention also provides a method for preparing the above-mentioned sea urchin-like nickel / titanium-based catalyst, which specifically comprises the following steps:

[0009] (1) using a smelting method to smelt nickel, titanium and aluminum metal elements in a molar ratio of 1:1:6 to 10 into a nickel-titanium-aluminum ternary alloy;

[0010] (2) subjecting the alloy powder obtained in step (1) to dealloying treatment using a sodium hydroxide solution to obtain a porous nickel-titanium solid solution;

[0011] (3) adding the porous nickel-titanium solid solution powder obtained in step (2) together with CH4N2S and 3 wt.% of the total mass of the reactants as a stabilizer into deionized water, stirring, and placing in a reactor for hydrothermal treatment; the molar ratio of the porous nickel-titanium solid solution powder to CH4N2S is 1:3;

[0012] (4) Filtering the hydrothermal treatment product obtained in step (3), and washing and drying the solid filtrate to obtain the target product, a sea urchin-like nickel / titanium-based catalyst.

[0013] Furthermore, in step (2), the concentration of the sodium hydroxide solution is 3-4 mol / L, the dealloying temperature is 25-30° C., and the dealloying time is 10-12 h.

[0014] Furthermore, in step (3), the temperature of the hydrothermal treatment is 190-210° C., and the time is 5-7 h.

[0015] The present invention also provides the use of the sea urchin-like nickel / titanium-based catalyst obtained by the above preparation method in MgH2 hydrogen storage, specifically, the sea urchin-like nickel / titanium-based catalyst is mechanically mixed with MgH2, wherein the addition amount of the sea urchin-like nickel / titanium-based catalyst is 5 to 20 wt.%.

[0016] The innovations of the present invention are as follows:

[0017] The present invention uses a nickel-titanium-aluminum ternary alloy as a precursor, first obtaining a porous nickel-titanium solid solution through dealloying. Hydrothermal sulfurization and oxidation treatments are then performed in the presence of CH₄N₂S, prompting NiS to grow within the pores of the nickel-titanium solid solution and then extend outward, forming a sea urchin-like structure. TiO₂ is dispersed within and on the surface of the NiS skeleton, resulting in a sea urchin-like nickel / titanium-based NiS@TiO₂ catalyst. In applications such as MgH₂ hydrogen storage, the sea urchin-like nickel / titanium-based catalyst can weaken the Mg–H bond, thereby lowering the dehydrogenation temperature of MgH₂. Furthermore, the Mg₂Ni, MgS, and MgO formed during the dehydrogenation process effectively inhibit the aggregation and growth of MgH₂ particles, thereby improving the cyclic stability of hydrogen absorption and dehydrogenation.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] (1) The preparation method of the provided sea urchin-like nickel / titanium-based catalyst is simple in process, safe and reliable, and easy to scale up for production.

[0020] (2) The preparation method of the provided sea urchin-like nickel / titanium-based catalyst uses non-precious metal nickel, titanium and aluminum as initial raw materials, which are widely available and low in cost.

[0021] (3) The provided sea urchin-like nickel / titanium-based catalyst is used for MgH2 hydrogen storage, which can reduce the initial hydrogen desorption temperature of MgH2 to 220℃ and has good cyclic stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 1 is the X-ray diffraction pattern of the nickel-titanium solid solution and the sea urchin-like nickel / titanium-based catalyst obtained in Example 1 of the present invention.

[0023] Figure 2 The following are scanning electron microscope photos and energy spectrum analysis diagrams of the sea urchin-like nickel / titanium-based catalyst obtained in Example 1 of the present invention.

[0024] Figure 3 2 are the temperature-increasing hydrogen release curves of the MgH2-based hydrogen storage materials and pure MgH2 in Examples 1 and 2 of the present invention.

[0025] Figure 4 This is the cyclic hydrogen desorption curve of the MgH2-based hydrogen storage material in Example 1 of the present invention.

[0026] Figure 5 1 and 2 are X-ray diffraction patterns of the MgH2-based hydrogen storage material and its 2nd and 30th hydrogen release products in Example 1 of the present invention. DETAILED DESCRIPTION

[0027] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments, but the present invention is not limited to the following embodiments.

[0028] Example 1

[0029] Nickel flakes, titanium particles, and aluminum flakes with a molar ratio of 1:1:8 were smelted into a nickel-titanium-aluminum ternary alloy by a smelting method, and the alloy was mechanically crushed into a powder with a particle size of less than 300 mesh; the alloy powder was poured into a 4 mol / L sodium hydroxide solution at 25°C for 12 hours for dealloying treatment, and the dealloyed solid product was washed and dried to obtain a porous nickel-titanium solid solution powder (its X-ray diffraction pattern is as shown in FIG). Figure 1 As shown); a porous nickel-titanium solid solution powder with a molar ratio of 1:3, CH4N2S and 3wt.% NH4Cl were added to deionized water, stirred and placed in a reactor for hydrothermal treatment (temperature 210°C, time 5h); the hydrothermal treatment product was filtered, and the solid filtrate was washed and dried to obtain the sea urchin-like nickel / titanium-based catalyst. Figure 1 and Figure 2 It can be seen that the obtained nickel / titanium-based catalyst is composed of TiO2 and NiS, and TiO2 is dispersed inside and on the surface of the NiS skeleton, and the overall structure is sea urchin-like. 10wt.% of sea urchin-like nickel / titanium-based catalyst was mixed with MgH2 by mechanical ball milling. Figure 3 It can be seen that the obtained MgH2-based hydrogen storage material starts to release hydrogen at 220℃ and basically ends at 370℃, with a hydrogen release amount of about 6.7wt.%. In comparison, the initial hydrogen release temperature of pure MgH2 is as high as 340℃ and the hydrogen release end temperature is about 450℃. Figure 4 It can be seen that the amount of hydrogen released by the MgH2-based hydrogen storage material after 30 cycles is 6.3wt.%, which has good cycle stability. Figure 5 It can be seen that the MgH2-based hydrogen storage material forms the phases Mg2Ni, MgS and MgO during the hydrogen desorption process, which can effectively inhibit the agglomeration and growth of MgH2 particles and help improve the cyclic stability of hydrogen absorption and desorption.

[0030] Example 2

[0031] A ternary nickel-titanium-aluminum alloy is smelted with nickel sheets, titanium particles and aluminum sheets in a molar ratio of 1:1:8 by a smelting method, and the alloy is mechanically crushed into a powder with a particle size of less than 300 mesh; the alloy powder is poured into a 4 mol / L sodium hydroxide solution at 25°C for dealloying treatment for 12 hours, and the dealloyed solid product is washed and dried to obtain a porous nickel-titanium solid solution powder; a porous nickel-titanium solid solution powder in a molar ratio of 1:3, CH4N2S and 3wt.% NH4Cl are added to deionized water, stirred and placed in a reactor for hydrothermal treatment (temperature of 200°C, time of 7 hours); the hydrothermal treatment product is filtered, and the solid filtrate is washed and dried to obtain the sea urchin-like nickel / titanium-based catalyst. 5wt.% of the sea urchin-like nickel / titanium-based catalyst is mixed with MgH2 by mechanical ball milling. Figure 3 It can be seen that the obtained MgH2-based hydrogen storage material starts to release hydrogen at 240°C and basically ends at 385°C, with a hydrogen release amount of about 7.2wt.%.

[0032] Example 3

[0033] A nickel-titanium-aluminum ternary alloy is smelted by a smelting method with a molar ratio of 1:1:6, with nickel sheets, titanium particles and aluminum sheets, and the alloy is mechanically crushed into a powder with a particle size of less than 300 mesh; the alloy powder is poured into a 3 mol / L sodium hydroxide solution at 30°C for dealloying treatment for 10 hours, and the dealloyed solid product is washed and dried to obtain a porous nickel-titanium solid solution powder; the porous nickel-titanium solid solution powder with a molar ratio of 1:3, CH4N2S and 3 wt.% NH4Cl are added to deionized water, stirred and placed in a reactor for hydrothermal treatment (temperature of 190°C, time of 7 hours); the hydrothermal treatment product is filtered, and the solid filtrate is washed and dried to obtain the sea urchin-like nickel / titanium-based catalyst. By mechanically ball milling 15 wt.% of a sea urchin-like nickel / titanium-based catalyst and MgH2, the initial and final dehydrogenation temperatures of MgH2 can be reduced to 240 and 380°C, respectively, and the dehydrogenation amount is about 6.4 wt.%.

[0034] Example 4

[0035] A nickel-titanium-aluminum ternary alloy is smelted by a smelting method with a molar ratio of 1:1:10, and the alloy is mechanically crushed into a powder with a particle size of less than 300 mesh; the alloy powder is poured into a 4 mol / L sodium hydroxide solution at 30°C for dealloying treatment for 10 hours, and the dealloyed solid product is washed and dried to obtain a porous nickel-titanium solid solution powder; the porous nickel-titanium solid solution powder with a molar ratio of 1:3, CH4N2S and 3wt.% NH4Cl are added to deionized water, stirred and placed in a reactor for hydrothermal treatment (temperature of 200°C, time of 6 hours); the hydrothermal treatment product is filtered, and the solid filtrate is washed and dried to obtain the sea urchin-like nickel / titanium-based catalyst. By mechanically ball milling 20 wt.% of a sea urchin-like nickel / titanium-based catalyst and MgH2, the initial and final dehydrogenation temperatures of MgH2 can be reduced to 250 and 375°C, respectively, and the dehydrogenation amount is about 6.0 wt.%.

Claims

1. A sea urchin-like nickel / titanium-based catalyst, characterized in that The catalyst consists of two phases, NiS and TiO2, and TiO2 is dispersed inside and on the surface of the NiS skeleton, and the whole catalyst is in a sea urchin-like shape.

2. The method for preparing the sea urchin-like nickel / titanium-based catalyst according to claim 1, wherein The steps include: (1) using a smelting method to smelt nickel, titanium and aluminum metal elements in a molar ratio of 1:1:6 to 10 into a nickel-titanium-aluminum ternary alloy; (2) subjecting the alloy powder obtained in step (1) to dealloying treatment using a sodium hydroxide solution to obtain a porous nickel-titanium solid solution; (3) adding the porous nickel-titanium solid solution powder obtained in step (2) together with CH4N2S and 3 wt.% of the total mass of NH4Cl into deionized water, stirring, and placing in a reactor for hydrothermal treatment; the molar ratio of the porous nickel-titanium solid solution powder to CH4N2S is 1:3; (4) Filtering the hydrothermal treatment product obtained in step (3), and washing and drying the solid filtrate to obtain a sea urchin-like nickel / titanium-based catalyst.

3. The method for preparing the sea urchin-like nickel / titanium-based catalyst according to claim 2, wherein: The concentration of the sodium hydroxide solution in step (2) is 3-4 mol / L, the dealloying temperature is 25-30° C., and the dealloying time is 10-12 h.

4. The method for preparing the sea urchin-like nickel / titanium-based catalyst according to claim 2, wherein: In the step (3), the temperature of the hydrothermal treatment is 190-210° C., and the time is 5-7 hours.

5. Use of the sea urchin-like nickel / titanium-based catalyst as claimed in claim 1 in magnesium hydride hydrogen storage.

6. Use of the sea urchin-like nickel / titanium-based catalyst in magnesium hydride hydrogen storage according to claim 5, characterized in that: The sea urchin-like nickel / titanium-based catalyst is mechanically mixed with MgH2, wherein the addition amount of the sea urchin-like nickel / titanium-based catalyst is 5 to 20 wt.%.

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