Synthesis method of Pd-based metal hydride

Abstract

The invention relates to the field of hydride preparation, in particular to a Pd-based metal hydride synthesis method which comprises the following steps: adding reactants into a reaction kettle, adding a solvent into the reaction kettle, feeding the reactants into an 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 (hydrogen embrittlement effect) 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 particularly to a method for synthesizing Pd-based 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), ultimately leading to 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", lacking in-depth understanding of the dynamic evolution mechanism of hydrogen embrittlement. In particular, there are still controversies about the microscopic kinetic processes of hydrogen atom diffusion-bonding-phase transformation. Regarding hydrogen embrittlement simply as the "prime culprit of failure" ignores the potential for controllable synthesis of hydrides hidden behind it, and this cognitive limitation urgently needs to be broken through.

[0003] Traditional hydride synthesis mainly relies on complex processes such as hydrogenation (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 characteristic that hydrogen atoms spontaneously invade the metal lattice and form ordered hydrides in the phenomenon of hydride embrittlement precisely reveals 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 can be reversely transformed into "constructiveness", it is expected to achieve controllable synthesis of hydrides under mild conditions, breaking through the temperature / pressure limitations of traditional methods. Summary of the Invention

[0004] The present invention proposes a new strategy of "hydrogen embrittlement synthesis", driving 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, etc.

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

[0006] A method for synthesizing a Pd-based metal hydride comprises the following steps:

[0007] The reactants are added to a reactor, and a solvent is added to the reactor. The reactants are at least one of Pd or a Pd metal alloy, 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. The reaction device is heated to form metal hydride through the hydrogen embrittlement effect.

[0008] As a further solution of the present invention: the reactant is a metal block, a metal foil or a metal powder, and can also be a nano-metal element or a nano-metal compound.

[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, and most preferably 200°C.

[0014] As a further embodiment of the present invention, the washing step is performed using n-hexane.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] The present invention can synthesize metal hydrides by means of hydrothermal reaction (hydrogen embrittlement effect) under relatively mild conditions without directly using hydrogen. 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 XRD pattern for the formation process of palladium hydride. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are only a part rather than all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0019] Example 1 Preparation of Palladium Hydride

[0020] Refer to Figure 1 , add palladium foil, ethylene glycol and sodium hydroxide into the inner lining of a 5 ml PPL 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 n-hexane, and the obtained product after drying is PbH 0.706 . Further, the present invention can control the thickness of the metal foil, reaction time and reaction temperature to further regulate the metal hydride product. For every 7 mg of metal palladium foil (0.5 mm × 0.5 mm × 0.025 mm), the reaction temperature is 180 °C and the reaction time is 12 hours, and PdH with good purity can be obtained 0.706 ; when the reaction time ≤ 4 hours, the product is a mixture of metallic palladium and PdH 0.706 ; when the reaction time exceeds 12 hours, the metal foil will completely react and there will be no hydride product. The specific relationship between temperature and product purity is shown in Table 1.

[0021] Table 1 Relationship between temperature and product purity

[0022] Condition 180℃2h 180℃4h 180℃6h Product <![CDATA[90% Pd + 10% PdH 0.706 > <![CDATA[70% Pd + 30% PdH 0.706 > <![CDATA[50% Pd + 50% PdH 0.706 > Condition 180℃8h 180℃10h 180℃12h Product <![CDATA[10% Pd + 90% PdH 0.706 > <![CDATA[5% Pd + 95% PdH 0.706 > <![CDATA[PdH 0.706 (greater than 95)]]>

[0023] Figure 1 are XRD patterns corresponding to different reaction conditions. As can be seen from Figure 1 , at the beginning stage of the reaction (180 °C, 2 h), the XRD diffraction peaks are mainly Pd, and the peak intensity of PdH 0.706 is very weak, indicating that the product is mainly metallic Pd at this time and the yield of PdH 0.706 is very low; in the middle stage of the reaction (180 °C, 2 h - 8 h), PdH 0.706The peak of the summit gradually increases. When it is at 180 °C for 12 h, the XRD pattern only has the diffraction peak of PdH completely, which also indicates that the reaction is complete at this time and the product is all PdH. 0.706 The purity of the product is obtained by XRD quantitative analysis. 0.706 .

[0024] 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 Pd-based metal hydride, characterized in that, It includes the following steps: Add the reactants into a reaction kettle, add a solvent into the reaction kettle. The reactant is at least one of Pd or Pd metal alloy, and the solvent is an acid solution or an alcohol solution. 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 Pd-based metal hydride according to claim 1, characterized in that, The reactant is a metal block, a metal foil or metal powder.

3. The synthesis method of the Pd-based metal hydride according to claim 1, wherein, The acid solution is an inorganic acid solution or an organic acid solution.

4. The synthesis method of the Pd-based 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 Pd-based 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 Pd-based 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 Pd-based metal hydride according to claim 1 or 2, characterized in that, The temperature in the oven is 70 - 280 °C.

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