Palladium-copper alloy material, preparation method and application thereof

Abstract

The present application relates to the field of palladium copper alloy material, discloses a kind of palladium copper alloy material and its preparation method and application.The method for preparing high-purity hydrogen includes at least part of hydrogen in hydrogen-containing gas is made to pass through palladium copper alloy material, wherein, palladium copper alloy material contains Pd and Cu, and the molar ratio of Pd and Cu is 100:(90-120), the crystal structure of the palladium copper alloy material is body-centered cubic packing, lattice parameter k is 0.2890-0.2996nm, the half-peak width of at least one characteristic peak in the XRD pattern of the palladium copper alloy material is less than or equal to 0.1571 in the range of 30°-90° of 2θ.Using the palladium copper alloy material of the present application can not only improve the purity of hydrogen, but also improve the recovery rate of hydrogen.

Description

Technical Field

[0001] This invention relates to the field of palladium-copper alloy materials, specifically to a palladium-copper alloy material, its preparation method, and its applications. Background Technology

[0002] Hydrogen energy is considered one of the most promising clean energy sources of the 21st century, playing an increasingly important role in fields such as chemical industry, food, semiconductor industry, communication base stations, low-temperature superconductivity, military, and aviation. The utilization of hydrogen energy involves hydrogen production, separation and purification, and storage and transportation. Hydrogen production methods mainly include coal-to-hydrogen, hydrocarbon-to-hydrogen, bio-hydrogen, and water electrolysis, but the purity of the produced hydrogen is not high. To meet the industrial demand for various high-purity hydrogens, hydrogen must be separated and purified. Common hydrogen separation methods include cryogenic separation, pressure swing adsorption (PSA), and membrane separation. In the field of high-purity hydrogen production, palladium membrane separation technology has the advantages of low investment, low energy consumption, high stability, and environmental friendliness. Addressing the problem of the difficulty in completely removing trace impurities (such as N2, Ar, and CO2) during traditional PSA, palladium membrane separation, following the principle of dissolution and diffusion, perfectly solves the above problems, making it a highly promising high-purity hydrogen separation and purification process.

[0003] However, when the temperature is <573K, pure palladium film will form α-PdH after dissolving hydrogen. and β-PdH Two solid solutions with different lattice parameters (a) were presented. Repeated dissolution and efflux cycles of this structure led to uneven contraction and expansion of the palladium film, resulting in hydrogen embrittlement and cracking. This significantly limited the application of palladium films under low temperature and high pressure conditions.

[0004] Currently, to ensure the quality of high-purity hydrogen, existing technologies mostly use carbon fiber materials for hydrogen storage tanks and long-tube trailers for transportation. Therefore, the increased costs during storage and transportation are inevitably added to the price of high-purity hydrogen. The high price has become a barrier limiting the application of high-purity hydrogen in various fields. Therefore, it is essential to develop room-temperature on-site separation and purification technology for ordinary hydrogen to produce hydrogen with a purity greater than 99.9999% that meets the requirements of chip manufacturing in the electronics and semiconductor industries. Meanwhile, with the integration of natural gas and hydrogen into the pipeline network, large-scale pipeline transportation can significantly reduce the storage and transportation costs of hydrogen. However, the separation and purification problems faced by high-purity hydrogen in room-temperature on-site applications also urgently need to be solved. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems existing in the prior art and to provide palladium-copper alloy materials, their preparation methods, and applications.

[0006] To achieve the above objectives, a first aspect of the present invention provides a method for preparing high-purity hydrogen gas. The method includes permeating at least a portion of the hydrogen gas in a hydrogen-containing gas through a palladium-copper alloy material. The palladium-copper alloy material contains Pd and Cu, with a molar ratio of Pd to Cu of 100:(90-120). The palladium-copper alloy material has a body-centered cubic crystal structure with a lattice parameter k of 0.2890-0.2996 nm. In the XRD pattern of the palladium-copper alloy material, the full width at half maximum (FWHM) of at least one characteristic peak of 2θ in the range of 30°-90° is less than or equal to 0.1571.

[0007] A second aspect of the present invention provides a palladium-copper alloy material, which is the palladium-copper alloy material defined above or the product of the alloying treatment described above.

[0008] Through the above technical solution, this invention utilizes a palladium-copper alloy material with a body-centered cubic stacked crystal structure. On the one hand, it can improve the purity of hydrogen, obtaining high-purity hydrogen (greater than 99.9999%); on the other hand, it can improve the hydrogen recovery rate, achieving a high-purity hydrogen recovery rate exceeding 99%. The palladium-copper alloy material with a body-centered cubic stacked crystal structure of this invention can be used under low-temperature (room temperature) and high-pressure conditions, broadening the application range of palladium films. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the separation of the gas to be separated using a palladium-copper alloy material;

[0010] Figure 2 This is a scanning electron microscope image of the palladium-copper alloy material of Example F1.

[0011] Explanation of reference numerals in the attached figures

[0012] 1. Gas inlet 2. Permeate outlet

[0013] 3. Residual outlet on the side 4. Support body

[0014] 5 Palladium-copper alloy material 6 end caps Detailed Implementation

[0015] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0016] The first aspect of the present invention provides a method for preparing high-purity hydrogen gas, the method comprising permeating at least a portion of the hydrogen gas in a hydrogen-containing gas through a palladium-copper alloy material, wherein the palladium-copper alloy material contains Pd and Cu, and the molar ratio of Pd to Cu is 100:(90-120), the crystal structure of the palladium-copper alloy material is body-centered cubic, the lattice parameter k is 0.2890-0.2996 nm, and the full width at half maximum (FWHM) of at least one characteristic peak of 2θ in the range of 30°-90° in the XRD pattern of the palladium-copper alloy material is less than or equal to 0.1571.

[0017] In this invention, "body-centered cubic packing" refers to a close-packed arrangement in a cubic crystal system, which includes two lattice points, one at the vertex and one at the body center. That is, eight atoms are located at the eight vertices of the cube, and one atom is located at the center of the cube. The eight atoms at the vertices are tangent to the central atom.

[0018] In this invention, "lattice parameter k" refers to the physical dimensions of a unit cell in a crystal lattice, representing a fundamental structural parameter of a crystalline material. The lattice parameter k represents the edge length of the unit cell, that is, the edge length of each parallelepiped unit, and it is directly related to the bonding energy between atoms. A unit cell in three-dimensional space generally has three lattice parameters, denoted by a, b, and c. Based on the morphological distribution of the Bravais lattice, in the cubic crystal structure (body-centered cubic packing) involved in this invention, these three constants are all equal, and therefore can be represented by parameter k. Changes in k reflect changes in the composition, stress state, etc., within the crystal. The lattice parameter k can be determined using X-ray diffraction (XRD) or atomic force microscopy (AFM).

[0019] According to the present invention, preferably, the half-width at half maximum (WHM) of all characteristic peaks of 2θ in the range of 30°-90° in the XRD pattern of the palladium-copper alloy material is less than or equal to 0.1571, more preferably less than or equal to 0.0702, and usually greater than or equal to 0.0349.

[0020] According to the present invention, preferably, in the XRD pattern of the palladium-copper alloy material, the full width at half maximum (FWHM) of the characteristic peak at 2θ = 43° ± 1° (i.e., the characteristic peak of crystal plane (110)) is less than or equal to 0.0524 (e.g., 0.0524, 0.05, 0.045, 0.04, 0.035, 0.03, 0.025, 0.02, 0.015, 0.01, and any two of the above points), more preferably 0.02-0.04, or the full width at half maximum (FWHM) of the characteristic peak at 2θ = 53° ± 1° (i.e., the characteristic peak of crystal plane (111)) is less than or equal to 0. 0.0873 (e.g., 0.0873, 0.07, 0.06, 0.0524, 0.05, 0.045, 0.04, 0.035, 0.03, 0.025, 0.02, 0.015, 0.01, and any two of the above points), more preferably 0.034-0.06, or the full width at half maximum (FWHM) of the characteristic peak at 2θ = 62° ± 1° (i.e., the characteristic peak of the crystal plane (200)) is less than or equal to 0.0873 (e.g., 0.0873, 0.07, 0.06, 0.0524, 0.05, 0.045, 0.01, and any two of the above points). The full width at half maximum (FWHM) of the characteristic peak at 2θ = 70° ± 1° (i.e., the characteristic peak of the crystal plane (210)) is less than or equal to 0.1047 (e.g., 0.1047, 0.09, 0.08, 0.07, 0.06, 0.0524, 0.05, 0.045, 0.04, 0.035, 0.03, 0.025, 0.02, 0.015, 0.04, 0.05, 0.06, 0.0524, 0.05, 0.045, 0.04, 0.035, 0.03, 0.025, 0.02, 0.015, 0.04, 0.05, 0.065 ...5, 0.05, 0.065, 0.05, 0.065, 0.05, 0.065, 0.05, 0.065, 0.05, 0.065, 0.05, 0.065, 0.05, 0.065, 0.05, 0.065, 0.05, 0.065, 0.05, 0.065, 0.05, 0.065, 0.05, 0 1, and the range formed by any two points mentioned above), more preferably 0.07-0.082, or the half-width of the characteristic peak at 2θ=79°±1° (i.e., the characteristic peak of the crystal plane (211)) is less than or equal to 0.1571 (e.g., 0.1571, 0.1, 0.09, 0.08, 0.07, 0.06, 0.0524, 0.05, 0.045, 0.04, 0.035, 0.03, 0.025, 0.02, 0.015, 0.01, and the range formed by any two points mentioned above), more preferably 0.085-0.11. The "half-width" is defined as the peak width at half the peak height, i.e., the half-height width. The half-height width is converted into radians according to the Debye-Scherrer formula (D=Kγ / Bcosθ), and the radian value characterizes the size of the half-width. When the palladium-copper alloy material has no characteristic peak at the corresponding 2θ, the half-peak width is considered to be 0.

[0021] According to the present invention, preferably, the thickness of the palladium-copper alloy material is 0.5-30 μm (for example, 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, and any two of the above), more preferably 5-15 μm, and even more preferably 6-8 μm.

[0022] According to the present invention, preferably, the palladium-copper alloy material is a film material.

[0023] According to the present invention, preferably, the palladium-copper alloy material is attached to the support body, and the thickness of the support body is 0.1-20mm (for example, 0.1mm, 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 15mm, 20mm, and any two of the above), more preferably 2-5mm.

[0024] The present invention also provides a method for preparing palladium-copper alloy material, comprising: depositing Pd and Cu on a support, and then alloying the support on which Pd and Cu have been deposited, wherein the molar ratio of Pd to Cu is 100:(90-120).

[0025] According to the method for preparing palladium-copper alloy material of the present invention, preferably, the alloying treatment is carried out as follows: after treatment in an activating atmosphere at a temperature of 570-600℃ and a pressure of 0.37-0.52MPa for 4-7 hours; the temperature is then reduced to 120-180℃ at a rate of 55-85℃ / min. The activating atmosphere consists of gases including H2, N2, and NH3, and the volume ratio of H2, N2, and NH3 is 100:(27-77):(1-21). The palladium-copper alloy material obtained according to this preferred embodiment has higher hydrogen permeability or stability (smaller half-width at half-maximum corresponding to characteristic peaks). The addition of alkaline gas NH3 enables faster activation of the palladium-based alloy film, resulting in a more stable body-centered cubic structure and a smaller half-width at half-maximum in the XRD pattern.

[0026] In this invention, the pressure of the alloying process is generally controlled by adjusting the amount of gas used to provide the activating atmosphere. After being cooled to below 180°C at a specific rate, it can be cooled to room temperature for later use.

[0027] According to the method for preparing palladium-copper alloy material of the present invention, preferably, the total thickness of Pd and Cu deposited on the support is 0.5-30 μm (e.g., 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, and any two of the above), more preferably 5-15 μm, and even more preferably 6-8 μm.

[0028] According to the preparation method of the palladium-copper alloy material of the present invention, preferably, the thickness of the support is 0.1-20 mm (e.g., 0.1 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 15 mm, 20 mm, and any two of the above), preferably 2-5 mm. The support can be provided by materials commonly used in the art that can withstand the operating temperature of the present invention without affecting the hydrogen permeability, that is, materials that do not deform or affect the hydrogen permeability at the operating temperature of the present invention. While ensuring excellent hydrogen permeability, in order to obtain better mechanical and thermal stability and reduce the amount of palladium used (reducing costs), preferably, the support is a porous support, which can be selected from at least one of porous ceramics, porous glass, porous metals (such as porous stainless steel), porous quartz, and polymers, more preferably from at least one of porous ceramics, porous metals, and polymers. Generally, the porosity distribution of the support ranges from 15-75%, and the average pore size is 0.05-0.4 μm. To obtain a tubular membrane, the support is preferably a tubular support. The porous ceramic material can be γ-Al₂O₃, with a porosity distribution ranging from 25-66% and an average pore size of 0.12-0.4 μm. The porous stainless steel material can be 316L(Fe₂O₃). 69 Cr 17 Ni 12 Mo2 has a porosity ranging from 32% to 71% and an average pore size of 0.08 to 0.36 μm. The polymer material can be polyimide, with a porosity ranging from 15% to 37% and an average pore size of 0.05 to 0.22 μm. The "porosity range" and "average pore size" can both be determined using nitrogen physical adsorption.

[0029] According to the present invention, preferably, the conditions for at least a portion of the hydrogen in a hydrogen-containing gas to permeate through the palladium-copper alloy material include: a transmembrane pressure difference greater than or equal to 0.1 MPa (e.g., 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 1 MPa, 10 MPa, and any two of the above), preferably 0.5-1 MPa; and a system separation temperature of 298-373 K℃ (e.g., 298 K, 300 K, 310 K, 320 K, 330 K, 340 K, 350 K, 360 K, 373 K, and any two of the above), preferably 300-320 K. Herein, the transmembrane pressure difference refers to the difference between the pressure on the inner side of the membrane (the side where the feed gas enters) and the pressure on the outer side (the side where hydrogen permeates out).

[0030] According to the present invention, the hydrogen-containing gas can be various hydrogen-containing gas samples to be purified, such as hydrogen samples with a purity of less than or equal to 99.9% by volume (e.g., 99-99.9% by volume).

[0031] A second aspect of the present invention provides a palladium-copper alloy material, which is the palladium-copper alloy material defined above or the product of the alloying treatment described above.

[0032] The present invention reduces the hydrogen permeation activation energy of the membrane material (palladium-copper alloy material) by performing heat treatment at a specific temperature and then cooling it at a specific rate, thereby improving the hydrogen permeation efficiency and stability of the membrane material (the half-peak width corresponding to the characteristic peak is small). The use of ammonia will further improve the hydrogen permeability and stability of the membrane material.

[0033] The present invention will be described in detail below through embodiments. In the following embodiments, the inner surface of the support is sealed with polytetrafluoroethylene (PTFE) material, and therefore the PTFE material is peeled off before application or performance testing.

[0034] Examples F1-F3

[0035] Using a porous stainless steel tube as the support (tubular, inner diameter: 10.5 mm, outer diameter: 13.5 mm; average pore size: 0.25 μm, porosity: 65%), the support was first soaked in anhydrous ethanol for 30 minutes to remove surface contaminants such as dust and grease. Then, the surface and inner side of the support were rinsed with deionized water and placed in warm water for vacuum rinsing to remove residual ethanol from the pores. Finally, it was placed in an oven and dried at 423 K for 4 hours. Based on Faraday's law, Pd and Cu were deposited on the support using electroplating, with the Pd / Cu molar ratio M as shown in Table 1. The effective film area was 32 cm². 2The electroplating conditions were as follows: using a conductive layer carrier as the working electrode, a platinum electrode (Pd plated) and a waveguide with a copper content of 99.999% (Cu plated) as the counter electrodes, and a saturated calomel electrode as the reference electrode, the metal ions (Pd) in the plating bath were concentrated at 30°C. 2+ Cu 2+ The concentration was 0.015-0.2 mol / L. Electroplating experiments were carried out using cyclic voltammetry, with the working voltage range being -0.60V to -0.90V, the scan rate being 0.0075V / s, the scan period being 1000, and the sensitivity being set to 0.0001A / V. Meanwhile, during the electroplating process, a plunger-type constant flow pump was used to add 0.05 mol / L ammonium palladium chloride ((NH4)2PdCl4) solution to the plating bath at a rate of 1-2 ml / min, 0.075 mol / L copper nitrate (Cu(NO3)2) solution at a rate of 0.5-1.5 ml / min, ethylenediamine (EDA, 99%, analytical grade) at a rate of 0.05-0.12 ml / min, disodium ethylenediaminetetraacetate (EDTA-2Na, 99%, analytical grade) at a rate of 0.025-0.05 ml / min, and bipyridine (C... 10 H8N2 (99%, analytical grade). The plating solution was vigorously stirred (1000 r / min) while being added to the above solution. Every 30 min of electroplating, the working electrode, cleaned with distilled water, was immersed for 10 min in 0.05 mol / L phosphoric acid (H3PO4) solution and 0.05 mol / L dipotassium hydrogen phosphate (K2HPO4) solution, respectively. After the cyclic voltammetry procedure, the working electrode was treated in distilled water at 100℃ for 10 min before being removed. The Pd and Cu deposited support was subjected to high-temperature alloying treatment. The alloying treatment was performed as follows: under an activating atmosphere, at temperature T1 and pressure P, the temperature was lowered to T2 at a rate V. The activating atmosphere consisted of H2, N2, and NH3, with the volume ratio of H2, N2, and NH3 equal to R1. The amount of activating atmosphere gas provided was such that the alloying pressure was P. See Table 1 for details of the parameters.

[0036] Table 1

[0037] condition F1 F2 F3 T1 / ℃ 570 580 600 P / MPa 0.52 0.4 0.37 R1 100:27:1.28 100:40:5 100:50:10 t / h 4 5 4 V / (℃ / min) 60 65 70 T2 / ℃ 120 160 140 M 100:110 100:90 100:120

[0038] Comparative Example FD1

[0039] The process is carried out in accordance with Example F1, except that the gas providing the activating atmosphere is only N2.

[0040] Comparative Example FD2

[0041] The process is carried out in accordance with Example F1, except that the gas providing the activating atmosphere is only H2.

[0042] Comparative Example FD3

[0043] The process is carried out in accordance with Example F1, except that the gas providing the activating atmosphere is only argon.

[0044] Comparative Example FD4

[0045] The process is carried out in accordance with Example F1, except that the gases providing the activation atmosphere are hydrogen and CO2 (volume ratio of 1:1).

[0046] Comparative Example FD5

[0047] The process was carried out in accordance with Example F1, except that the temperature was reduced to T2 at a rate of V = 5°C / min.

[0048] Comparative Example FD6

[0049] The process was carried out in accordance with Example F1, except that the alloying temperature T1 = 700°C.

[0050] Comparative Example FD7

[0051] The alloying process was carried out in accordance with Example F1, except that the alloying pressure P = 0.1 MPa.

[0052] Comparative Example FD8

[0053] The procedure was carried out in accordance with Example F1, except that the molar ratio of Pd to Cu was changed to 100:1000.

[0054] Comparative Example FD9

[0055] The procedure was carried out in accordance with Example F1, except that the molar ratio of Pd to Cu was changed to 100:1.

[0056] Test case

[0057] (I) The materials obtained after alloying treatment in each embodiment and comparative example (i.e., palladium-copper alloy materials) were characterized. The characterization method is as follows, and the crystal structure parameters of the palladium-copper alloy materials are shown in Table 2.

[0058] The crystal phase structure analysis of the palladium-copper alloy was performed on an X'Pert PRO / PANalytical automated X-ray diffractometer manufactured by Philips, Netherlands. The experimental conditions were Cu K α X-rays (λ = 0.1543 nm), tube voltage 40 kV, current 40 mA, diffraction angle 2θ scan range 10-90°. The interplanar spacing of the sample was calculated using the Bragg equation.

[0059] d=λ / 2sinθ

[0060] Where λ corresponds to Cu K α The wavelength of the radiation, θ is the angle of the diffraction peak.

[0061] The crystal structure of the palladium-copper alloy was tested at the European Synchrotron Radiation Facility (beam BM25A) in France, which has higher resolution, with synchrotron radiation λ = 0.0618886 nm or 0.077449 ​​nm and tube voltage of 10.0335 keV or 20.0335 keV. Initially, a 10 × 1 mm sample was used. 2 The sample was placed in a 2mm diameter quartz capillary tube, with both ends sealed with quartz wool. The capillary tube was then mounted on a rotating sample stage (to ensure uniform temperature and a larger X-ray irradiation area). The test temperature range was 298-473K (heated by a hot air blower), and the pressure range was 10... -4 The test atmosphere was -130 kPa. Hydrogen gas was first introduced and treated for 30 minutes, then a vacuum was drawn, and helium gas was introduced as a protective gas for measurement.

[0062] Methods for testing the lattice parameters of palladium-copper alloy materials: Combining the above-mentioned in-situ XRD tests, the cell parameters of the palladium-based alloy material are obtained (represented by three cell constants a, b, and c, and the three inter-edge angles α, β, and γ). According to the formula d1 = a / (α... 2 +β 2 +γ 2 ) 0.5 d2=b / (α) 2 +β 2 +γ 2 ) 0.5 d3=c / (α) 2 +β 2 +γ 2 ) 0.5The interplanar spacing (d1 d2 d3) of the corresponding characteristic crystal planes is calculated. That is, the PdCu alloy material obtained in this invention belongs to the body-centered cubic (BCC) structure, and its characteristic crystal planes include (110), (111), (200), (210), and (211). At the same time, according to the X-ray diffraction results, a series of different characteristic crystal plane ratios (the intensity corresponding to different crystal planes) can be obtained. For example, in the PdCu alloy material obtained in this invention, the (110) plane corresponds to the characteristic peak at 2θ = 43° ± 1°, the (111) plane corresponds to the characteristic peak at 2θ = 53° ± 1°, the (200) plane corresponds to the characteristic peak at 2θ = 62° ± 1°, the (210) plane corresponds to the characteristic peak at 2θ = 70° ± 1°, and the (211) plane corresponds to the characteristic peak at 2θ = 79° ± 1°. By using HighScorePlus analysis software and combining the peak intensities of the above characteristic crystal planes, the lattice parameter k of the corresponding material is calculated.

[0063] The thickness of the palladium-copper alloy material was tested using a scanning electron microscope (model: JSM-7610F). The thickness of the alloy film was determined by measuring the corresponding scale according to the magnification. The surface smoothness of the obtained palladium-copper alloy material could also be observed using the scanning electron microscope. The surface smoothness of the palladium-copper alloy material in Example F1 is as follows: Figure 2 As shown in the figure, the palladium-copper alloy material obtained by the method of the present invention has a uniform structure and a smooth surface. The surface smoothness of the palladium-copper alloy materials in Examples F2-F3 is similar to that in Example F1, and will not be shown here again.

[0064] The method for testing the half-peak width (WHM) of palladium-copper alloy materials is as follows: based on the XRD spectrum test results, combined with HighScorePlus software analysis, the radian value of the WHM is obtained.

[0065] E act (Hydrogen permeation activation energy, unit: kJ·mol) -1 The test method involves measuring the hydrogen permeation rate from 573 K to 773 K under a transmembrane pressure difference of 0.1 MPa, combined with the Arrhenius equation J. H2 =J H2 °exp(-E act / RT), calculated through measurement, where J H2 It is the hydrogen permeation diffusion rate, J H2 ° is the hydrogen permeation diffusion coefficient, R is the gas constant, and T is the absolute temperature. The higher the hydrogen permeation activation energy, the higher the hydrogen mass transfer resistance of the composite membrane material, and the more difficult it is for hydrogen to permeate and diffuse through the composite membrane.

[0066] J H2 (Hydrogen permeation diffusion rate, unit: mol·m) -2·s -1 The test method involves measuring the volume of hydrogen passing through the palladium-based composite membrane per minute (liters) at 20℃ and a transmembrane pressure difference of 0.1 MPa, and then normalizing it to the hydrogen permeation rate (mol·m²) based on the membrane area (square meters). -2 ·s -1 ).

[0067] J N2 (Nitrogen permeation diffusion rate, unit: mmol·m) -2 ·s -1 The test method involves measuring the volume (mL) of nitrogen gas passing through the palladium-based composite membrane per minute at 20℃ and a transmembrane pressure difference of 0.1 MPa, and then normalizing it to the hydrogen permeation rate (mmol·m²) based on the membrane area (m²). -2 ·s -1 ).

[0068] Table 2

[0069]

[0070]

[0071] Note: BCC+FCC in Table 2 indicates that it includes both body-centered cubic packing and face-centered cubic close packing.

[0072] (II) Performance Testing

[0073] The performance of the palladium-copper alloy material prepared in the above embodiments in the preparation of high-purity hydrogen was tested.

[0074] like Figure 1 As shown, the palladium-copper alloy material 5, prepared above and attached to the support 4, is sealed in a tubular reactor using a cap 6. First, nitrogen gas is introduced into the inner and outer sides of the palladium-copper alloy material at flow rates of 10 mL / min and 30 mL / min, respectively. The temperature is increased to 523 K at a rate of 1 K / min to activate the composite membrane for 4 hours. Then, the gas to be separated (ordinary hydrogen with a purity of 99.1%) is introduced into the tubular reactor through the gas inlet 1. Under the separation action of the palladium-copper alloy material, high-purity hydrogen is discharged from the permeate-side outlet 2, and the remaining components are discharged from the permeate-side outlet 3. The separation temperature is controlled at 300 K, and the pressure difference between the inside and outside of the composite membrane (P0) is maintained. 外侧 -P 内侧The pressure was 0.8 MPa. The gas components to be separated, high-purity hydrogen, and residual components during the separation process were analyzed online using a Shanghai Tianmei SCION-456 gas chromatograph equipped with FID and PDHID detectors. Product distribution and hydrogen purity changes were monitored in real time. High-purity hydrogen was tested every 5 hours. The continuous operating time was recorded when the purity of high-purity hydrogen decreased to 99.999%. The initial separation values ​​and experimental measurements after reaching the continuous operating time are shown in Table 3. The purity of high-purity hydrogen is represented by S. 高 The hydrogen recovery rate is expressed in H2. 回 , where H 回 The calculation formula is:

[0075] H 回 = Amount of hydrogen on the permeate side / (Amount of hydrogen on the permeate side + Amount of hydrogen on the residual permeate side)

[0076] Table 3

[0077]

[0078]

[0079] As shown in Table 3, the method using the palladium-copper alloy material with a body-centered cubic stacked crystal structure of the present invention can, on the one hand, improve the purity of hydrogen to obtain high-purity hydrogen (purity greater than 99.9999%), and on the other hand, improve the hydrogen recovery rate, making the recovery rate of high-purity hydrogen higher than 99%. Furthermore, none of the palladium-copper alloy materials (F1-F3) of the present invention cracked after the testing was completed.

[0080] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing high-purity hydrogen gas, characterized in that, The method involves permeating at least a portion of the hydrogen in a hydrogen-containing gas through a palladium-copper alloy material, wherein the palladium-copper alloy material contains Pd and Cu, and the molar ratio of Pd to Cu is 100:(90-120), the palladium-copper alloy material has a body-centered cubic crystal structure, a lattice parameter k of 0.2890-0.2996 nm, and the XRD pattern of the palladium-copper alloy material shows 2θ at 30 nm. o -90 o The full width at half maximum (FWHM) of at least one characteristic peak within the range is less than or equal to 0.1571; wherein, the preparation method of palladium-copper alloy material includes: depositing Pd and Cu on a support, and then alloying the support on which Pd and Cu have been deposited, wherein the activation atmosphere of the alloying treatment includes H2, N2 and NH3, and the volume ratio of H2, N2 and NH3 is 100:(27-77):(1-21).

2. The method according to claim 1, wherein, In the XRD pattern of the palladium-copper alloy material, 2θ is at 30°. o -90 o The full width at half maximum (FWHM) of all characteristic peaks within the range is less than or equal to 0.1571.

3. The method according to claim 1 or 2, wherein, In the XRD pattern of the palladium-copper alloy material, 2θ=43 o ±1 o The full width at half maximum (FWHM) of the characteristic peak at that location is less than or equal to 0.0524, or 2θ = 53. o ±1 o The full width at half maximum (FWHM) of the characteristic peak at that location is less than or equal to 0.0873, or 2θ = 62. o ±1 o The full width at half maximum (FWHM) of the characteristic peak at that location is less than or equal to 0.0873, or 2θ = 70°. o ±1 o The full width at half maximum (FWHM) of the characteristic peak at that location is less than or equal to 0.1047, or 2θ = 79. o ±1 o The full width at half maximum (FWHM) of the characteristic peak at that location is less than or equal to 0.1571. And / or, the thickness of the palladium-copper alloy material is 0.5-30µm.

4. The method according to claim 1 or 2, wherein, The thickness of the palladium-copper alloy material is 5-15µm.

5. The method according to claim 1 or 2, wherein, The palladium-copper alloy material is a film-like material.

6. The method according to claim 1 or 2, wherein, The palladium-copper alloy material is attached to the support body, and the thickness of the support body is 0.1-20mm.

7. The method according to claim 1 or 2, wherein, The palladium-copper alloy material is attached to the support body, and the thickness of the support body is 2-5mm.

8. The method according to claim 1, wherein, The alloying treatment further includes: treating in an activating atmosphere at a temperature of 570-600℃ and a pressure of 0.37-0.52MPa for 4-7 hours; then reducing the temperature to 120-180℃ at a rate of 55-85℃ / min.

9. The method according to claim 8, wherein, The total thickness of Pd and Cu deposited on the support is 0.5-30µm.

10. The method according to claim 8, wherein, The total thickness of Pd and Cu deposited on the support is 5-15µm.

11. The method according to claim 8, wherein, The thickness of the support is 0.1-20mm.

12. The method according to claim 8, wherein, The thickness of the support is 2-5mm.

13. The method according to claim 1, wherein, The conditions for allowing at least a portion of the hydrogen in a hydrogen-containing gas to pass through a palladium-copper alloy material include: a transmembrane pressure difference greater than or equal to 0.1 MPa and a system separation temperature of 298-373 K.

14. A palladium-copper alloy material, characterized in that, The palladium-copper alloy material is the palladium-copper alloy material as defined in any one of claims 1-7 or the product of alloying treatment as described in any one of claims 8-12.

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