Synthesis method of IV / VB group transition metal hydride

Abstract

The invention relates to the field of hydride preparation, in particular to a synthesis method of IV / VB group transition metal hydride, which comprises the following steps: adding reactants into a reaction kettle, adding a solvent into the reaction kettle, adding NaF into the reaction kettle, enabling the reactants to be at least one of IV / VB group transition metal simple substances or alloys, enabling the solvent to be an acid solution or an alcohol solution, and enabling the NaF to be added into the reaction kettle; feeding the reaction kettle into a drying oven for heating; and washing and drying the heated sample to obtain a finished product. According to the present invention, the metal hydride can be synthesized by using the hydrothermal reaction under the mild condition without directly using hydrogen, such that the vacancy of the hydride synthesis technology is filled, and the condition is provided for the research in the metal hydride field.

Description

Technical Field

[0001] The present invention relates to the field of hydride preparation, and specifically to a method for synthesizing group IV / VB transition metal hydrides. Background Art

[0002] The hydrogen embrittlement effect is an important failure mechanism that has long been concerned in the field of materials science. It refers to the phenomenon that hydrogen atoms invade the metal lattice under the drive of stress or chemical potential, resulting in a decrease in the toughness of the material and brittle fracture. Among them, hydride embrittlement, as a typical form of hydrogen embrittlement, is manifested as the enrichment and diffusion of hydrogen atoms at bulk defects (grain boundaries or dislocations) to form brittle hydride phases (such as titanium hydride, zirconium hydride), which ultimately cause catastrophic failures in key fields such as nuclear power and aerospace. Traditional research has focused on hydrogen embrittlement inhibition strategies, including material composition optimization (such as adding hydrogen trap elements), surface protective coatings (such as ceramic coatings), and environmental hydrogen concentration control. However, existing strategies are mostly based on the idea of "passive defense" and lack an in-depth understanding of the dynamic evolution mechanism of hydrogen embrittlement. In particular, the microscopic kinetic process of hydrogen atom diffusion-bonding-phase transformation remains controversial. Regarding hydrogen embrittlement simply as the "prime culprit of failure" while ignoring the potential for controllable synthesis of hydrides hidden behind it, this cognitive limitation urgently needs to be broken through.

[0003] Traditional hydride synthesis mainly relies on complex processes such as the hydrogenation method (high temperature, high pressure), chemical vapor deposition (CVD), and mechanical alloying, facing challenges such as high energy consumption, complex preparation processes, limited product purity (derived oxidation phase by-products), and difficult structure regulation (such as grain coarsening, uncontrollable defects). In contrast, the characteristics of hydrogen atoms spontaneously invading the metal lattice and forming ordered hydrides in the phenomenon of hydride embrittlement precisely reveal the potential of the metal itself as a "dynamic reactor": the lattice distortion during the hydrogen embrittlement process may provide a directional diffusion channel for hydrogen atoms, and stress-induced electron rearrangement may stabilize the hydride phase. If the "destructiveness" of hydrogen embrittlement is reversely transformed into "constructiveness", it is expected to achieve controllable synthesis of hydrides under mild conditions and break through the temperature / pressure limitations of traditional methods. Summary of the Invention

[0004] The present invention proposes a new strategy of "hydrogen embrittlement synthesis", which drives the controllable synthesis of hydrides through the hydrogen embrittlement effect. Using multi-scale metals (metal foils, powders, etc.) and (hydrochloric acid / sulfuric acid / oleic acid / ethanol, etc.) as precursors, by regulating the concentration of the proton source (hydrochloric acid / sulfuric acid / oleic acid / ethanol, etc.), high-purity hydrides are successfully created under mild conditions (70 - 280 °C). The purpose of the present invention is to provide a process for synthesizing metal hydrides under mild conditions using a proton source as the hydrogen source and utilizing the hydrogen embrittlement effect. This process has the advantages of low equipment investment (no need for large equipment), cleanliness (no use of fossil energy, no CO2 emissions), and applicability to regional production.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A method for synthesizing a Group IV / VB transition metal hydride comprises the following steps:

[0007] The reactants are added to the reactor, and the solvent and NaF are added to the reactor. The reactants are at least one of the transition metal elements or alloys of Group IV / VB, and the solvent is an acid solution or an alcohol solution. The reactor is placed in an oven for heating. The heated sample is washed and dried to obtain a finished product. No hydrogen is required in the process of generating hydride. The source of hydrogen is the solvent. If the reactant is Ti and the solvent is oleic acid, the reaction principle is: Ti+2C 17 H 33 COOH=(C 17 H 33 COO)2Ti+TiH2. Similar reactions will occur with other reactants, and the Group IV / VB transition metal is at least one of Ti, Zr, Hf, V, Nb, and Ta.

[0008] As a further solution of the present invention: the reactant is a metal block, a metal foil or a metal powder.

[0009] As a further solution of the present invention: the acid solution is an inorganic acid solution or an organic acid solution, and the concentration of the acid solution is 0.1-2 mol / L.

[0010] As a further embodiment of the present invention, the inorganic acid is at least one of hydrochloric acid, sulfuric acid, hydrobromic acid, hydroiodic acid, hydrofluoric acid, hydrosulfuric acid, carbonic acid, phosphoric acid, boric acid, silicic acid, arsenic acid, antimonic acid, titanic acid, tungstic acid, stannic acid and zincic acid.

[0011] As a further embodiment of the present invention, the organic acid is at least one of formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, capric acid, lauric acid, palmitic acid, stearic acid, palmitic acid, oleic acid, linoleic acid, linolenic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, citric acid, malic acid, tartaric acid, benzoic acid, o-hydroxybenzoic acid, terephthalic acid and caffeic acid.

[0012] As a further embodiment of the present invention, the alcohol in the alcohol solution is at least one of methanol, ethanol, n-propanol, isopropanol, n-butanol, 2-butanol, tert-butanol, allyl alcohol, propargyl alcohol, cyclohexanol, benzyl alcohol, ethylene glycol, glycerol and pentaerythritol.

[0013] As a further embodiment of the present invention: the temperature in the oven is 70-280°C, preferably 150-250°C.

[0014] As a further solution of the present invention: washing is performed using ethanol, deionized water and acid solution.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] The present invention can synthesize metal hydrides by using hydrothermal reaction (hydrogen embrittlement effect) under relatively mild conditions without directly using hydrogen gas. This invention fills the gap in the synthesis technology of such hydrides and provides conditions for the research in the field of metal hydrides. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is the XRD pattern of the titanium hydride formation process.

[0018] Figure 2 It is the SEM photograph of titanium hydride.

[0019] Figure 3 It is the XRD pattern of the vanadium hydride formation process.

[0020] Figure 4 It is the SEM photograph of vanadium hydride.

[0021] Figure 5 It is the XRD pattern of the zirconium hydride formation process.

[0022] Figure 6 It is the SEM photograph of zirconium hydride.

[0023] Figure 7 It is the XRD pattern of the niobium hydride formation process.

[0024] Figure 8 It is the SEM photograph of niobium hydride.

[0025] Figure 9 It is the XRD pattern of the hafnium hydride formation process.

[0026] Figure 10 It is the SEM photograph of hafnium hydride.

[0027] Figure 11 It is the XRD pattern of the tantalum hydride formation process.

[0028] Figure 12 It is the SEM photograph of tantalum hydride. DETAILED DESCRIPTION OF THE INVENTION

[0029] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0030] Example 1 Preparation of Titanium Hydride

[0031] See Figures 1 - 2 , in an inert gas (argon) glove box, titanium foil, sulfuric acid and surface treatment agent NaF were added to the inner lining of a 5 ml polytetrafluoroethylene reaction kettle, and then encapsulated in a reaction kettle of the same volume and transferred to an oven for heating. After natural cooling, it was washed with ethanol, and the obtained product after drying was TiH₂. Further, the present invention can control the thickness of the metal foil, reaction time and reaction temperature to further regulate the metal hydride product. Each piece of titanium metal foil (0.5 mm × 0.5 mm × 0.025 mm), the reaction temperature was 200 °C, and the reaction time was 6 hours, and TiH₂ with better purity was obtained. The purity of the product was obtained by XRD quantitative analysis. The relationship between the specific conditions and the product is shown in Table 1.

[0032] Table 1 Relationship between temperature and product purity

[0033]

[0034] Figure 1 are the XRD patterns corresponding to different reaction conditions. From Figure 1 it can be seen that at the beginning stage of the reaction (200 °C for 1 h), the XRD diffraction peaks were mainly Ti, and the peak intensity of TiH₂ was very weak, indicating that the product was mainly metal Ti at this time and the yield of TiH₂ was very low; when the reaction proceeded to (200 °C for 2 h - 4 h), it was found from the XRD pattern that the diffraction peaks of TiH₂ continuously increased, and TiH₂ was completely formed at (200 °C for 6 h).

[0035] Example 2 Preparation of vanadium hydride

[0036] See Figures 3 - 4 , in an inert gas (argon) glove box, vanadium foil and sulfuric acid were added to the inner lining of a 5 ml polytetrafluoroethylene reaction kettle, and then encapsulated in a reaction kettle of the same volume and transferred to an oven for heating for 2 hours. After natural cooling, it was washed with n-hexane, and the obtained product after drying was VH₂; each piece of titanium metal foil (0.5 mm × 0.5 mm × 0.025 mm), the reaction temperature was 180 °C, and the reaction time was 2 hours, and VH₂ with better purity was obtained. The relationship between the specific conditions and the product is shown in Table 2.

[0037] Table 2 Relationship between temperature and product purity

[0038] Condition 160℃0.5h 160℃1h Product <![CDATA[90%V + 10%V2H]]> <![CDATA[80% V + 20% V2H]]> 160℃2h 180℃1h 180℃2h <![CDATA[VH 0.8 (greater than 95%)]]> <![CDATA[80% VH 0.8 + 20% VH2]]> <![CDATA[VH2 (greater than 95%)]]>

[0039] Figure 3 are the XRD patterns corresponding to different reaction conditions. From Figure 3It can be seen that at the beginning stage of the reaction (160°C for 0.5 h), the XRD diffraction peaks are mainly V, and the peak intensity of V2H is very weak, indicating that the product is mainly metallic Pd at this time and the yield of V2H is very low. When the reaction proceeds to (160°C for 2 h), the XRD pattern only shows the diffraction peaks of VH0.8, indicating that the product is all VH0.8 at this time. It can be found that when the reaction conditions are further improved, when the temperature is raised to 180°C, VH2 can be completely formed in 2 h. The purity of the product is obtained by quantitative analysis of XRD.

[0040] Preparation of Zirconium Hydride in Example 3

[0041] Refer to Figures 5 - 6 , put zirconium foil, sulfuric acid and the surface treatment agent NaF into the inner lining of a 5 ml polytetrafluoroethylene reaction kettle in an inert gas (argon) glove box, then seal it in a reaction kettle of the same volume and transfer it to an oven for heating. After natural cooling, wash it with ethanol, and the obtained product after drying is ZrH2. Further, the present invention can control the thickness of the metal foil, the reaction time and the reaction temperature to further regulate the metal hydride product. Each piece of titanium foil (0.5 mm × 0.5 mm × 0.025 mm), the reaction temperature is 180°C, and the reaction time is 10 hours, and ZrH2 with good purity is obtained. The purity of the product is obtained by quantitative analysis of XRD. The relationship between the specific conditions and the product is shown in Table 3.

[0042] Table 3 Relationship between Temperature and Product Purity

[0043]

[0044] Figure 5 are the XRD patterns corresponding to different reaction conditions. It can be seen from Figure 5 that at the beginning stage of the reaction (180°C for 2 h), the XRD diffraction peaks are mainly Zr, and the peak intensity of ZrH 1.6 is very weak, indicating that the product is mainly metallic Ti at this time and the yield of TiH 1.6 is very low. When the reaction proceeds to (180°C for 8 h), it can be found from the XRD pattern that there are only the diffraction peaks of ZrH 1.6 , indicating that ZrH 1.6 is formed at this time. As the reaction time continues to increase, XRD shows that the peaks of ZrH2 will appear, and ZrH2 is completely formed at (180°C for 10 h).

[0045] Preparation of Niobium Hydride in Example 4

[0046] Refer to Figures 7 - 8, niobium foil, sulfuric acid, and surface treatment agent NaF were added to the inner lining of a 5 ml polytetrafluoroethylene reaction kettle in an inert gas (argon) glove box. Then, it was sealed in a reaction kettle of the same volume and transferred to an oven for heating. After natural cooling, it was washed with ethanol, and the obtained product after drying was NbH₂. Further, the present invention can control the thickness of the metal foil, reaction time, and reaction temperature to regulate the metal hydride product. For each piece of titanium foil (0.5 mm × 0.5 mm × 0.025 mm), the reaction temperature was 180 °C, and the reaction time was 10 hours, obtaining NbH₂ with better purity. The relationship between the specific conditions and the product is shown in Table 4.

[0047] Table 4 Relationship between temperature and product purity

[0048] Condition 180℃7h 180℃8h Product NbH (greater than 95%) <![CDATA[30% NbH + 70% NbH2]]> Condition 180℃9h 180℃10h Product <![CDATA[50% NbH + 95% NbH2]]> <![CDATA[NbH2 (greater than 95%)]]>

[0049] Figure 7 are the XRD patterns corresponding to different reaction conditions. From Figure 7 it can be seen that at the beginning of the reaction (180 °C for 7 h), the XRD diffraction peaks were mainly NbH and there were no other diffraction peaks, indicating that the product was completely formed as NbH; as the reaction proceeded (180 °C for 8 - 9 h), it was found from the XRD pattern that the diffraction peaks of NbH₂ gradually began to increase and reached the strongest at (180 °C for 10 h), and the peak of NbH completely disappeared, indicating that NbH₂ was formed at this time. The purity of the product was obtained by XRD quantitative analysis.

[0050] Example 5 Preparation of hafnium hydride

[0051] Refer to Figures 9 - 10 , hafnium foil, sulfuric acid, and surface treatment agent NaF were added to the inner lining of a 5 ml polytetrafluoroethylene reaction kettle in an inert gas (argon) glove box. Then, it was sealed in a reaction kettle of the same volume and transferred to an oven for heating. After natural cooling, it was washed with ethanol, and the obtained product after drying was HfH₂. Further, the present invention can control the thickness of the metal foil, reaction time, and reaction temperature to regulate the metal hydride product. For each piece of titanium foil (0.5 mm × 0.5 mm × 0.025 mm), the reaction temperature was 180 °C, and the reaction time was 10 hours, obtaining HfH₂ with better purity. The relationship between the specific conditions and the product is shown in Table 5.

[0052] Table 5 Relationship between temperature and product purity

[0053] Condition 180℃6h 180℃7h Product <![CDATA[30% Hf + 70% HfH 1.7 > <![CDATA[10% Hf + 90% HfH 1.7 > 180℃8h 180℃9h 180℃10h <![CDATA[HfH 1.7 (greater than 95%)]]> <![CDATA[50% HfH 1.7 + 95% HfH2]]> <![CDATA[HfH2 (greater than 95%)]]>

[0054] Figure 9 are the XRD patterns corresponding to different reaction conditions. From Figure 9 it can be seen that at the beginning of the reaction (180 °C for 6 h), the XRD diffraction peaks were mainly Hf, HfH1.7 The diffraction peaks are very weak, indicating that the product is mainly Hf and the yield of hydride is very low. As the reaction proceeds (180 °C for 7 - 8 h), it can be found from the XRD pattern that the diffraction peaks of HfH 1.7 gradually start to increase and reach the strongest at (180 °C for 8 h), and the peak of Hf completely disappears, indicating the formation of HfH 1.7 at this time. As the reaction proceeds (180 °C for 8 - 10 h), it can be found from the XRD pattern that the diffraction peaks of HfH2 gradually start to increase and reach the strongest at (180 °C for 10 h), and the peak of HfH 1.7 also completely disappears, indicating the formation of HfH2 at this time. The purity of the product is obtained by quantitative analysis of XRD.

[0055] Example 6 Preparation of tantalum hydride

[0056] Refer to Figures 11 - 12 , put tantalum foil, sulfuric acid and surface treatment agent NaF into the inner lining of a 5 ml polytetrafluoroethylene reaction kettle in an inert gas (argon) glove box, then encapsulate it in a reaction kettle of the same volume and transfer it to an oven for heating. After natural cooling, wash it with ethanol, and TaH is obtained after drying. Further, the present invention can control the thickness of the metal foil, reaction time and reaction temperature to further regulate the metal hydride product. Each piece of metal titanium foil (0.5 mm × 0.5 mm × 0.025 mm), the reaction temperature is 240 °C, and the reaction time is 10 hours, and TaH with better purity is obtained. The relationship between the specific conditions and the product is shown in Table 6.

[0057] Table 6 Relationship between temperature and product purity

[0058] Condition 240℃8h 240℃10h Product <![CDATA[Ta2H (greater than 95%)]]> TaH (greater than 95%)

[0059] Figure 11 are the XRD patterns corresponding to different reaction conditions. It can be seen from Figure 11 that at the beginning of the reaction (240 °C for 8 h), the XRD diffraction peaks are mainly Ta2H and there are no other diffraction peaks. When the reaction proceeds to (240 °C for 8 h - 10 h), it can be found from the XRD pattern that the diffraction peaks of TaH continuously increase and TaH is completely formed at (240 °C for 10 h). The purity of the product is obtained by quantitative analysis of XRD.

[0060] In addition, it should be understood that although this specification is described according to the embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for synthesizing a Group IV / VB transition metal hydride, characterized in that, It includes the following steps: Add the reactants into a reaction kettle, add a solvent and NaF into the reaction kettle. The reactants are at least one of group IV / VB transition metal simple substances or alloys, the solvent is an acid solution or an alcohol solution, and then send the reaction kettle into an oven for heating; wash and dry the heated sample to obtain the finished product.

2. The synthesis method of the Group IV / VB transition metal hydride according to claim 1, characterized in that, The reactants are metal blocks, metal foils or metal powders.

3. The synthesis method of the Group IV / VB transition metal hydride according to claim 1, characterized in that, The acid solution is an inorganic acid solution or an organic acid solution.

4. The synthesis method of the group Ⅳ / ⅤB transition metal hydride according to claim 3, characterized in that, The inorganic acid is at least one of hydrochloric acid, sulfuric acid, hydrobromic acid, hydroiodic acid, hydrofluoric acid, hydrosulfuric acid, carbonic acid, phosphoric acid, boric acid, silicic acid, arsenic acid, antimonous acid, titanic acid, tungstic acid, stannic acid and zincic acid.

5. The synthesis method of the Group IV / VB transition metal hydride according to claim 3 or 4, characterized in that, The organic acid is at least one of formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, capric acid, lauric acid, palmitic acid, stearic acid, palmitoleic acid, oleic acid, linoleic acid, linolenic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, citric acid, malic acid, tartaric acid, benzoic acid, o-hydroxybenzoic acid, terephthalic acid and caffeic acid.

6. The synthesis method of the Group IV / VB transition metal hydride according to claim 5, characterized in that, The alcohol in the alcohol solution is at least one of methanol, ethanol, n-propanol, isopropanol, n-butanol, 2-butanol, tert-butanol, allyl alcohol, propargyl alcohol, cyclohexanol, benzyl alcohol, ethylene glycol, glycerol and pentaerythritol.

7. The synthesis method of the Group IV / VB transition metal hydride according to claim 1 or 2, characterized in that, The temperature in the oven is 70 - 280 °C.

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