Preparation method of metal organic framework material (HKUST-1) and black copper oxide (CuO) composite hydrogen-resistant coating

Abstract

The invention belongs to the technical field of metal surface hydrogen-resistant coatings, and particularly discloses a preparation method of a metal organic framework material (HKUST-1) / copper oxide (CuO) double-layer composite hydrogen-resistant coating (CuO at HKUST-1). The preparation method comprises the following steps: preparing a black copper oxide coating (BO) on the surface of steel by adopting a normal-temperature electrically-assisted chemical oxidation technology, then directly growing an HKUST-1 layer on the surface of the black copper oxide coating by a one-step method under the condition of not additionally providing metal ions, and finally obtaining the HKUST-1 and CuO composite hydrogen-resistant coating. The CuO-coated HKUST-1 composite coating has excellent hydrogen barrier property. The work provides a new technology for the development of composite coatings on the inner surfaces of hydrogen storage and transportation equipment and other equipment in the presence of hydrogen.

Description

Technical Field

[0001] This invention belongs to the field of functional composite coating materials technology, specifically relating to, and is particularly applicable to, the preparation of hydrogen-blocking protective coatings for hydrogen-contaminated steel equipment. Background Technology

[0002] With the increasing importance of hydrogen energy in the clean energy system, the safety of various hydrogen-related equipment in the hydrogen energy industry is attracting more and more attention. However, the high diffusivity and low molecular weight of hydrogen easily cause hydrogen embrittlement in steel, seriously threatening the service safety of hydrogen-related equipment. Therefore, the development of efficient hydrogen-barrier composite coatings has become a research hotspot in recent years. Traditional inorganic oxide coatings mainly rely on their dense crystal structure to provide excellent shielding performance. However, due to their complex preparation process and high cost, oxide coatings have not yet been widely used in the field of protective coatings for hydrogen-related equipment. Iron oxide (BO) coatings are a traditional chemical conversion film with good density and environmental friendliness, but their application in the field of hydrogen barrier is still lacking. In recent years, metal-organic frameworks (MOFs) have become a research hotspot for novel hydrogen capture materials due to their porosity and adsorption properties. MOF materials have open metal sites, which can actively capture hydrogen molecules and hydrogen atoms through physical adsorption and chemical adsorption, significantly improving hydrogen barrier performance. This invention proposes a novel strategy for a composite hydrogen barrier coating with a dual mechanism of "passive shielding + active capture". Based on black oxide, a metal-organic framework material coating is further grown in situ on its surface to construct a two-layer composite hydrogen barrier coating with excellent hydrogen barrier performance. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of existing technologies by providing a method for preparing a composite hydrogen-barrier coating of a metal-organic framework material (HKUST-1) and black copper oxide (CuO). This invention employs room-temperature electro-assisted chemical oxidation to prepare the black copper oxide hydrogen-barrier coating, and then uses the copper oxide coating as a metal source to directly grow the metal-organic framework coating in a one-step process without the need for an additional metal source. The bilayer composite coating obtained by this preparation method exhibits excellent hydrogen-barrier performance.

[0004] The technical solution of this invention is:

[0005] 1. A method for preparing a hydrogen barrier coating composed of a metal-organic framework material (HKUST-1) and black copper oxide (CuO), comprising the following steps:

[0006] (1) Prepare chemical oxidation solution: Take 1-5 parts of copper sulfate, 1-5 parts of nickel sulfate, 10-15 parts of potassium dihydrogen phosphate, 1-5 parts of sodium citrate, and 2-4 parts of ammonium molybdate and dissolve them in deionized water. Then adjust the pH value to 2-3.

[0007] (2) Preparation of copper oxide coating: At room temperature, a metal substrate is placed as the cathode in a blackening solution, and an electrode material is selected as the anode and placed in the blackening solution. A DC power supply is connected, and the current density of the DC power supply is set to 10-25 mA / cm². 2 This causes a black copper oxide coating to form on the substrate surface;

[0008] Preferably, the amount of deionized water in step 1 is 700 to 1000 parts.

[0009] Preferably, nitric acid or sulfuric acid is used to adjust the pH value in step 1.

[0010] Preferably, the electrode material in step 2 is a Pt sheet or a graphite rod.

[0011] (3) In-situ growth of the HKUST-1 metal-organic framework coating: The CuO sample was immersed in a mixed precursor solution containing 30-60 parts H3BTC and 50-80 parts sodium formate, reacted at room temperature for 3-6 hours, and dried to form an HKUST-1 crystal film.

[0012] Compared with the prior art, the present invention has the following advantages:

[0013] This invention presents a novel method for preparing a hydrogen-barrier coating composed of a metal-organic framework (HKUST-1) and black copper oxide (CuO). Furthermore, it is the first to utilize a black copper oxide coating as a metal source, directly growing the HKUST-1 coating on the surface of the coating via a hydrothermal method. Metal-organic frameworks (MOFs) have become a research hotspot for novel hydrogen capture materials due to their porosity and adsorption properties. In particular, copper-containing MOFs (such as HKUST-1) possess open metal sites, enabling the active capture of hydrogen molecules and atoms through Kubas interactions and chemisorption, significantly improving hydrogen barrier performance. Therefore, this self-ion-donating in-situ constructed metal-organic framework-enhanced copper oxide hydrogen-barrier coating not only passively and physically shields hydrogen but also actively captures infiltrated hydrogen using the metal-organic framework (MOF). Thus, the composite coating exhibits excellent hydrogen barrier performance. This work aims to combine the functions of passive shielding and active hydrogen capture, which is beneficial for designing and preparing novel hydrogen-barrier composite coatings and their potential industrial applications. Based on the double-layer composite hydrogen barrier coating provided by this invention, a traditional organic coating can be further applied to obtain a multifunctional coating with anti-corrosion, drag reduction and hydrogen barrier properties. Attached Figure Description

[0014] Figure 1 A scanning electron microscope image of a black copper oxide coating;

[0015] Figure 2 Scanning electron microscope image of a metal-organic framework / black copper oxide composite coating;

[0016] Figure 3 XRD image of metal-organic framework material / black copper oxide composite coating;

[0017] Figure 4 Infrared image of metal-organic framework material / black copper oxide composite coating;

[0018] Figure 5 The hydrogen permeation curves for different coatings of this invention are shown below.

[0019] Figure 6 This is a bar chart showing the hydrogen diffusion coefficients of different coatings in this invention; Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Example 1

[0022] A self-ion-supplying in-situ constructed metal-organic framework-reinforced copper oxide hydrogen-barrier coating includes the following steps:

[0023] First, X65 steel tubing with dimensions of 20mm × 20mm × 1mm is selected as the substrate for the coating, leaving a 4cm margin. 2 The remaining part of the working surface is sealed with resin, and the working surface is then polished and cleaned.

[0024] The next step is to prepare a black copper oxide coating:

[0025] Take 3g of copper sulfate, 3g of nickel sulfate, 15g of sodium dihydrogen phosphate, 2g of sodium citrate, and 2g of ammonium molybdate and place them in a beaker. Add 1000mL of deionized water and mix. Then adjust the pH to 2 using nitric acid. At room temperature, place the substrate as the cathode in the blackening solution and the Pt sheet as the anode in the blackening solution. Connect a DC power supply with a current density of 15mA / cm². 2 After 25 minutes of standing, a black oxide hydrogen-barrier coating is formed on the working surface of the substrate; the substrate is then removed, left to stand for 5 minutes, rinsed with deionized water, and dried at room temperature.

[0026] Next, the CuO sample was immersed in a mixed precursor solution containing 30 mM H3BTC and 50 mM sodium formate, and hydrothermally reacted at 60°C for 3 hours. After drying, HKUST-1 crystal film was formed, thus obtaining the metal-organic framework material / black oxide composite hydrogen barrier coating.

[0027] Example 2

[0028] This embodiment is a comparative experiment based on the above embodiments, specifically:

[0029] This embodiment is basically the same as Example 1, except that the precursor solution for growing the metal-organic framework layer is prepared. The CuO sample is immersed in a mixed precursor solution containing 40 mM H3BTC and 70 mM sodium formate, and hydrothermally reacted at 50°C for 4 hours. After drying, the HKUST-1 crystal film is formed.

[0030] Example 3

[0031] This embodiment is a comparative experiment based on the above embodiments, specifically:

[0032] This embodiment is basically the same as Example 1, except that the precursor solution for growing the metal-organic framework layer is prepared. The CuO sample is immersed in a mixed precursor solution containing 50 mM H3BTC and 80 mM sodium formate, and hydrothermally reacted at 40°C for 6 hours. After drying, an HKUST-1 crystal film is formed.

[0033] Finally, the composite coating was tested and analyzed, as follows:

[0034] like Figure 1 and Figure 2 Before HKUST-1 crystal growth ( Figure 1 The BO coating surface exhibits a dense, spherical microstructure, with each micrometer-sized sphere composed of even smaller nanospheres, providing an ideal structural basis for the subsequent nucleation and growth of HKUST-1 nanocrystals. After 6 hours of growth, the surface is covered by a dense HKUST-1 crystalline film. Figure 2 ).

[0035] like Figure 3 X-ray diffraction (XRD) patterns were observed. The CuO coating exhibited distinct diffraction peaks at 2θ = 34°, 37°, 49°, 59°, 68°, and 73°, corresponding to the (002), (111), (112), (202), (220), and (311) crystal planes of CuO, respectively. After the growth of HKUST-1 crystals, a series of new diffraction peaks appeared in the BO@MOFs samples, especially at 2θ = 13.6°, 15.4°, 17.5°, and 19°, corresponding to the (400), (331), (440), and (600) crystal planes of HKUST-1, respectively.

[0036] like Figure 4 The Fourier transform infrared (FTIR) spectra shown further confirm the presence of functional groups in the BO@MOFs coating. The FTIR spectra at 1630, 1560, and 1440 cm⁻¹ further confirm the presence of functional groups in the BO@MOFs coating. -1 A characteristic absorption peak for C=O stretching vibration was observed at 1315 cm⁻¹. -1 The location is attributed to C–O stretching vibration, while 730cm -1The peak at 2500–3600 cm⁻¹ corresponds to the Cu–O stretching vibration. These five absorption peaks exhibit strong intensity, primarily due to the synergistic effect between oxygen and copper. Furthermore, the 2500–3600 cm⁻¹ peak... -1 The absorption bands within the range indicate the presence of adsorbed water and ethanol molecules in the sample.

[0037] like Figure 5 and Figure 6 As shown, Figure 5 The hydrogen permeation curves of different samples are shown, reflecting the osmotic current density (i a The relationship between hydrogen diffusion coefficient (D) and permeation time (t). The effective hydrogen diffusion coefficient (D) is obtained from these curves. eff )like Figure 6 As shown. D of each sample eff The values ​​are as follows: X80 steel (20.50×10) -7 cm 2 / s)>BO(5.50×10 -7 cm 2 / s)>EP(3.34×10 -7 cm 2 / s)>BO@MOFs(2.20×10 -7 cm 2 / s)>BO@MOFs / EP(1.51×10 -7 cm 2 / s). The lower the hydrogen diffusion coefficient, the better its hydrogen barrier performance, indicating that the composite coating can significantly reduce the hydrogen permeation rate and effectively inhibit hydrogen intrusion.

Claims

1. A method for preparing a hydrogen-barrier coating composed of a metal-organic framework material (HKUST-1) and black copper oxide (CuO), characterized in that: Includes the following steps: (I) Preparation of black oxide coating: An X65 steel sheet is used as the cathode, and a platinum plate is used as the anode. The plates are placed in an oxide solution, and a current density of 20-30 mA / cm² is applied. 2 Oxidation at room temperature for 10–30 minutes yields a black oxide coating with CuO as the main component. (II) In-situ growth of HKUST-1 metal-organic framework material: The CuO coated sample was immersed in a mixed precursor solution containing 30-60 parts of H3BTC and 50-80 parts of sodium formate, and hydrothermally reacted at 40-60°C for 3-6 hours. After drying, HKUST-1 crystal film was formed.

2. The method for preparing a black oxide coating according to claim 1, characterized in that: Oxidizing solution composition: Take 1-5 parts copper sulfate, 1-5 parts nickel sulfate, 10-15 parts potassium dihydrogen phosphate, 1-5 parts sodium citrate, and 2-4 parts ammonium molybdate, dissolve them in 700-1000 parts deionized water and mix, then adjust the pH value to 2-3 using nitric acid or sulfuric acid.

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