阅读说明：本技术 一种钛酸镍掺杂氢化铝锂储氢材料及其制备方法 (Nickel titanate doped lithium aluminum hydride hydrogen storage material and preparation method thereof ) 是由 孙立贤 岑文龙 徐芬 陈沛荣 赵莉 胡锦炀 夏永鹏 魏胜 程日光 张晨晨 詹浩 于 2019-12-11 设计创作，主要内容包括：本发明公开了钛酸镍掺杂氢化铝锂储氢材料,由氢化铝锂和钛酸镍NiTiO<Sub>3</Sub>混合机械球磨制得,所述钛酸镍NiTiO<Sub>3</Sub>由氯化镍和钛酸丁酯在乙二醇中反应生成的沉淀煅烧后制得,所述钛酸镍NiTiO<Sub>3</Sub>为长1-4μm、宽0.5-2μm大小的棒状形貌,钛酸镍NiTiO<Sub>3</Sub>的添加量占总质量的2-8 wt%。其制备方法包括：1)棒状钛酸镍制备；2)钛酸镍掺杂氢化铝锂储氢材料的制备。作为储氢领域的应用,催化剂掺杂量为2 wt%时,体系放氢温度降至95℃,放氢量达到7.0 wt%；当催化剂掺杂量为6 wt%时,体系放氢温度降至73℃,放氢量达到7.2 wt%。本发明具有以下优点：1、有效地改善氢化铝锂的放氢性能,添加少量催化剂后储氢材料还具有高的放氢量；2、具有成本低廉、制备工艺简单、反应可控等优点。(The invention discloses a nickel titanate doped lithium aluminum hydride hydrogen storage material, which is prepared from lithium aluminum hydride and nickel titanate NiTiO 3 Prepared by mixing and mechanical ball milling, the nickel titanate NiTiO 3 Prepared by calcining precipitate generated by the reaction of nickel chloride and butyl titanate in glycol, wherein the nickel titanate NiTiO 3 Is in a rod shape with the length of 1-4 mu m and the width of 0.5-2 mu m, and is nickel titanate NiTiO 3 The addition amount of (B) is 2-8wt% of the total mass. The preparation method comprises the following steps: 1) preparing rod-shaped nickel titanate; 2) preparing the nickel titanate doped lithium aluminum hydride hydrogen storage material. When the doping amount of the catalyst is 2wt%, the hydrogen releasing temperature of the system is reduced to 95 ℃, and the hydrogen releasing amount reaches 7.0 wt%; when the doping amount of the catalyst is 6 wt%, the hydrogen releasing temperature of the system is reduced to 73 ℃, and the hydrogen releasing amount reaches 7.2 wt%. The invention has the following advantages: 1. the hydrogen release performance of the lithium aluminum hydride is effectively improved, and the hydrogen storage material has high hydrogen release amount after a small amount of catalyst is added; 2. has the advantages of low cost, simple preparation process, controllable reaction and the like.)

1. A nickel titanate doped lithium aluminum hydride hydrogen storage material is characterized in that: NiTiO from lithium aluminium hydride and nickel titanate₃Prepared by mixing and mechanical ball milling, the nickel titanate NiTiO₃Prepared by calcining precipitate generated by the reaction of nickel chloride and butyl titanate in glycol, wherein the nickel titanate NiTiO₃Is a rod-shaped shape with the length of 1-4 mu m and the width of 0.5-2 mu m.

2. Root of herbaceous plantThe nickel titanate-doped lithium aluminum hydride hydrogen storage material of claim 1, wherein: the nickel titanate NiTiO₃The addition amount of (B) is 2-8wt% of the total mass.

3. The method for preparing a nickel titanate-doped lithium aluminum hydride hydrogen storage material according to claim 1, comprising the steps of:

step 1) preparing rod-shaped nickel titanate, namely adding nickel chloride into ethylene glycol by taking nickel chloride and butyl titanate to meet the mass ratio of a certain substance, stirring for dissolving, slowly adding butyl titanate into the solution for stirring reaction, centrifugally washing after the reaction is finished, drying and calcining to obtain the rod-shaped nickel titanate;

step 2) preparation of nickel titanate doped lithium aluminum hydride hydrogen storage material, weighing the rod-shaped nickel titanate NiTiO obtained in step 1 according to a certain mass fraction under the protection of argon gas₃And lithium aluminum hydride, and ball milling under certain conditions to obtain the nickel titanate doped lithium aluminum hydride hydrogen storage material.

4. The production method according to claim 3, characterized in that: the nickel chloride and the butyl titanate obtained in the step 1 are added into ethylene glycol according to the mass ratio of 1:1, and the concentrations of the nickel chloride and the butyl titanate are both 0.1-0.2 mol/L.

5. The production method according to claim 3, characterized in that: the reaction condition of the step 1 is that the reaction temperature is 20-30 ℃ and the reaction time is 3-6h under the magnetic stirring condition with the rotating speed of 80-100 rpm/min; the centrifugal washing conditions are that absolute ethyl alcohol is used as a solvent to avoid product hydrolysis, the centrifugal rate is 4000-; the drying condition is vacuum drying, the drying temperature is 80-100 ℃, and the drying time is 8-12 h; the calcining conditions are that the heating rate is 5-10 ℃/min, the calcining temperature is 600 ℃, the calcining time is 1-3 h, and the calcining atmosphere is air.

6. The production method according to claim 3, characterized in that: the mass fraction of the rodlike nickel titanate in the step 2 meets the condition that the addition amount accounts for 2-8wt% of the total mass; the ball milling conditions are that argon is used as protective atmosphere, the ball-material ratio is (60-40): 1, the ball milling speed is 400-.

7. The use of the nickel titanate-doped lithium aluminum hydride hydrogen storage material of claim 1 as a hydrogen storage material, wherein: when the doping amount of the catalyst is 2wt%, the hydrogen releasing temperature of the system is reduced to 95 ℃, and the hydrogen releasing amount reaches 7.0 wt%.

8. The use of the nickel titanate-doped lithium aluminum hydride hydrogen storage material of claim 1 as a hydrogen storage material, wherein: when the doping amount of the catalyst is 6 wt%, the hydrogen releasing temperature of the system is reduced to 73 ℃, and the hydrogen releasing amount reaches 7.2 wt%.

Technical Field

The invention relates to the technical field of hydrogen storage materials of new energy materials, in particular to nickel titanate (NiTiO)₃) A doped lithium aluminum hydride hydrogen storage material and a preparation method thereof.

Background

Traditional fossil energy such as petroleum and coal is gradually exhausted along with continuous use of human beings, so that the energy crisis caused by the depletion limits the development of the human society, and the search for green, efficient and renewable new energy to replace the fossil energy is common knowledge of all human beings and has achieved a great deal of research results. The hydrogen energy has the advantages of rich raw material sources, high energy density, environment-friendly products, renewability and the like, and becomes one of the most potential alternative energy sources at present. At present, the development and utilization of hydrogen energy mainly face three key problems of production, storage and transportation. Among them, how to safely and efficiently use hydrogen energy as a vehicle-mounted energy storage carrier is the research topic with the most challenging and commercial value at present. The traditional high-pressure liquid and gaseous hydrogen storage method has low efficiency, high production energy consumption and low use safety, restricts the commercial use of vehicle-mounted hydrogen storage, and the solid hydrogen storage technology has great research potential as a safe and efficient hydrogen storage method, and is a hydrogen storage method which is most likely to be used on a large scale in the future.

Lithium aluminum hydride (LiAlH)₄) The material has high hydrogen storage capacity (10.6 wt%), is considered to be one of the most potential solid hydrogen storage materials, but the use of the material as a vehicle-mounted energy storage carrier is restricted by the characteristics of over-high hydrogen release temperature, slow hydrogen release kinetics, poor reversibility and the like.

In recent years, researchers improve LiAlH through modes of doping modification, nanocrystallization, composite system construction, confinement and the like₄The hydrogen storage performance of (1) namely, the hydrogen release temperature is reduced, and the hydrogen release kinetics and reversibility are improved. Among them, doping modification, i.e., addition of a carbon-based material and various transition metal compounds (oxides, chlorides, nitrides, and the like), has been studied more. Reported examples are MWCNT and TiO₂、NiCl₂、Nb₂O₅And TiN etc. are effective in reducing LiAlH₄The initial hydrogen evolution temperature of (1).

Among the above dopants, TiO₂For LiAlH₄The initial hydrogen release temperature has the best improvement effect. Rangsubvigt et al used 10wt% TiO₂Doping catalytic LiAlH₄The initial hydrogen release temperature of the system is reduced to 95 ℃, and the final hydrogen release amount reaches 7.0 wt% [ Rangsubevit P, Purasaka P, Chaisuwan T, et al. Effects of carbon-based catalysts and catalysts on the hydrogen desorption/adsorption of LiAlH₄[J].Chemistry Letters, 2012, 41(10): 1368-1370.]. However, TiO₂Doping catalytic LiAlH₄The initial hydrogen release temperature is also higher than the maximum working temperature of the vehicle-mounted hydrogen storage system regulated by the U.S. department of energy, which is 85 ℃, and needs to be further improved.

NiTiO₃As a transition metal compound, NiTiO for Huang et al₃Doping with MgH₂Then, it was found that the hydrogen release temperature of the system could be lowered to 235 deg.C, and the final hydrogen release amount reached 6.4 wt% [ Huang X, Xiao X, Wang X, et al₃(TM= Ni and Co) forreversible hydrogen storage of magnesium hydride[J]. The Journal of PhysicalChemistry C, 2018, 122(49): 27973-27982.]. And TiO for Mukesh et al₂Doping with MgH₂Then, MgH was found₂+15 wt% TiO₂The hydrogen releasing temperature of the system can be reduced to 190 ℃, and finally the hydrogen is releasedThe amount of hydrogen reaches 6.3 wt% [ Jangir M, MeenaP, Jain I P, Improved hydrogen storage properties of MgH₂catalyzed with TiO₂[C]//AIP Conference Proceedings. AIP Publishing, 2018, 1953(1): 030059.]。

TiO of the above two metal compounds₂、NiTiO₃The technical scheme for catalyzing the hydrogen discharge performance of the hydrogen storage material presents the following technical problems: 1) the initial hydrogen release temperature is higher; 2) the addition of a large amount of catalyst results in a reduction in the final hydrogen release amount. However, by comparing Huang and Mukesh, MgH is used₂As a hydrogen storage material, different metal compounds are adopted to improve the hydrogen discharge performance, and MgH is subjected to reaction due to the difference of metal elements in the metal compounds₂A significant difference is produced in the catalytic effect of (c).

However, the inventor researches and finds that the hydrogen storage material and the catalyst have the problem of mutual matching, namely the root of the problem lies in solving the problem of matching of the hydrogen storage material and the catalyst.

Disclosure of Invention

The invention aims to provide a nickel titanate doped lithium aluminum hydride hydrogen storage material and a preparation method thereof.

The inventor researches and discovers that:

LiAlH₄middle Li⁺、Al³⁺Has an average ionic radius of 0.76 Å, 0.51 Å, respectively, and NiTiO₃In Ni²⁺、Ti⁴⁺Has an average ionic radius of 0.55 Å and 0.42 Å, respectively, in comparison with TiO₂Middle Ti⁴⁺Has an average ionic radius of 0.42 Å closer to LiAlH₄Middle Li⁺、Al³⁺The median value of the mean ionic radius of (a) is 0.635 Å;

research experience shows that when the average ionic radius of the cation of the catalyst is closer to LiAlH₄Middle Li⁺、Al³⁺At an intermediate value of the average ionic radius of (3), LiAlH can be more easily caused₄Destabilization of crystal lattice and reduction of LiAlH₄Activation energy of decomposition, thereby reducing LiAlH₄The hydrogen desorption temperature, from which it can be seen that NiTiO₃Should have a specific TiO ratio₂Better catalytic LiAlH₄The effect of hydrogen release performance.

Based on the theory, the inventor provides the NiTiO₃Doping with LiAlH₄The hydrogen storage material is regulated to effectively control LiAlH₄The hydrogen discharging process of the hydrogen storage material simultaneously realizes the following 2 technical effects:

1. reducing the initial hydrogen release temperature in the hydrogen release process;

2. the addition amount of the catalyst is reduced, so that more hydrogen is released in the whole hydrogen releasing process, and the final hydrogen releasing amount reaches 7.2 wt%.

In order to achieve the purpose of the invention, the invention adopts the technical scheme that:

a hydrogen storage material of lithium aluminum hydride doped with nickel titanate is prepared by mixing lithium aluminum hydride and rodlike nickel titanate and mechanically ball-milling; the nickel titanate NiTiO₃Prepared by calcining precipitate generated by the reaction of nickel chloride and butyl titanate in glycol, wherein the nickel titanate NiTiO₃Is in a rod shape with the length of 1-4 mu m and the width of 0.5-2 mu m; the addition amount of the nickel titanate accounts for 2-8wt% of the total mass.

The preparation method of the nickel titanate doped lithium aluminum hydride hydrogen storage material comprises the following steps:

step 1) preparing rod-shaped nickel titanate, namely adding nickel chloride into ethylene glycol according to the condition that the mass ratio of the nickel chloride to butyl titanate is 1:1, stirring and dissolving, slowly adding butyl titanate into the solution to obtain a solution with the concentration of both nickel chloride and butyl titanate being 0.1-0.2 mol/L, magnetically stirring for 3-6h at the rotating speed of 80-100 rpm/min under the condition of 20-30 ℃, carrying out stirring reaction, after the reaction is finished, using absolute ethyl alcohol as a solvent to avoid product hydrolysis, carrying out centrifugal washing at the centrifugal rate of 4000 and 6000 rpm/min for 6-10 min, carrying out vacuum drying for 8-12 h under the condition of 80-100 ℃, then heating to 600 ℃ at the heating rate of 5-10 ℃/min under the condition of air, and calcining for 1-3 h, calcining the mixture in the atmosphere to obtain the rodlike nickel titanate;

step 2) preparation of nickel titanate doped lithium aluminum hydride hydrogen storage material, under the protection of argon, weighing the mass fraction of the rod-shaped nickel titanate which accounts for 2-8wt% of the total massObtaining rod-shaped nickel titanate NiTiO₃And lithium aluminum hydride, under the condition of argon, in a ball-to-feed ratio of (60-40): 1, ball milling for 2-4 h at the ball milling rotation speed of 400-600 r/min to obtain the nickel titanate doped lithium aluminum hydride hydrogen storage material.

The nickel titanate doped lithium aluminum hydride hydrogen storage material is applied in the field of hydrogen storage,

when the doping amount of the catalyst is 2wt%, the hydrogen releasing temperature of the system is reduced to 95 ℃, and the hydrogen releasing amount reaches 7.0 wt%;

when the doping amount of the catalyst is 6 wt%, the hydrogen releasing temperature of the system is reduced to 73 ℃, and the hydrogen releasing amount reaches 7.2 wt%.

In order to prove that the nickel titanate material is successfully prepared, an X-ray diffraction test is carried out on the nickel titanate material, and the obtained diffraction spectrum can correspond to the standard PDF card PDF #76-0335 of nickel titanate, which indicates that the nickel titanate material is successfully prepared.

In order to prove the structural characteristics of the nickel titanate material, the material prepared by the invention has a rod-shaped structure with the length of 1-4 mu m and the width of 0.5-2 mu m through the test of a scanning electron microscope.

In order to prove the influence of the addition of nickel titanate as a catalyst on the hydrogen release performance of lithium aluminum hydride, NiTiO is prepared₃NiTiO with the content of 0wt%, 2wt%, 6 wt% and 8wt% respectively₃Doped lithium aluminum hydride hydrogen storage materials. The temperature rise dehydrogenation test is carried out on the product, and the addition of NiTiO is proved₃The initial hydrogen releasing temperature of the lithium aluminum hydride hydrogen storage material is 73-98 ℃, which is reduced by 56-81 ℃ compared with pure lithium aluminum hydride, and the total hydrogen releasing amount reaches 6.9-7.2 wt%.

Therefore, compared with the prior art, the invention has the following advantages:

1. the hydrogen storage material prepared by the invention effectively improves the hydrogen release performance of lithium aluminum hydride, has lower initial hydrogen release temperature, and obtains high final hydrogen release amount by adding a small amount of catalyst. When NiTiO₃When the doping amount of the catalyst is 6 wt%, the initial hydrogen release temperature is reduced to 73 ℃, the final hydrogen release amount reaches 7.2wt%, and the hydrogen release performance is greatly improved;

2. NiTiO prepared by the invention₃The method has the advantages of low cost, simple preparation process, controllable reaction and the like.

Drawings

FIG. 1 shows the NiTiO prepared according to the embodiment 1 of the present invention₃XRD pattern and NiTiO of₃Standard PDF card atlas;

FIG. 2 shows a prepared NiTiO rod according to example 1 of the present invention₃A field emission scanning electron microscope image of (a);

FIG. 3 shows NiTiO doping according to embodiments 1-3 of the present invention₃LiAlH with contents of 6 wt%, 2wt% and 8wt%, respectively₄The dehydrogenation graph of (a);

FIG. 4 is a 0wt% NiTiO doped sample of comparative example 1 according to the present invention₃LiAlH of₄Dehydrogenation profile of (a).

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings, which are given by way of examples, but are not intended to limit the present invention.