An in-situ grown PEMEC anode, its preparation method and its application in PEM hydrogen production

Abstract

The present invention provides an in-situ grown PEMEC anode, a preparation method thereof, and its application in PEM hydrogen production. The above-mentioned preparation method comprises: immersing a Ti substrate in an etching reagent solution to obtain a Ti-F substrate; placing the Ti-F substrate in an alkaline solution for hydrothermal reaction to obtain a Ti-OH substrate; coating a metal source on the surface of the Ti-OH substrate, drying, and calcining to obtain an in-situ grown PEMEC anode. The present invention also provides an in-situ grown PEMEC anode prepared by the above method and its application in PEM hydrogen production. The present invention uses mild conditions to activate the carrier, converting the inert TiO2 film on the surface of the Ti substrate into an active Ti-OH species, thereby realizing chemical bonding between the Ti substrate carrier and the metal catalyst layer such as iridium and gold, enhancing the interaction between the carrier and the catalyst layer, and effectively improving the stability of the anode.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrode preparation for water electrolysis devices, and specifically relates to an in-situ grown PEMEC anode, a preparation method thereof, and application thereof in PEM hydrogen production. Background Art

[0002] Among the technologies for producing hydrogen by water electrolysis, proton exchange membrane electrolysis (PEMEC) has the advantages of compact design, high current density, and high hydrogen purity, and is therefore considered to be one of the powerful methods for producing green hydrogen.

[0003] At present, PEM water electrolysis hydrogen production technology is still far from large-scale commercial application. In the process of water electrolysis, the anode oxygen evolution reaction (OER) involves 4e - The complex reaction pathways and high activation energy are believed to be the main reasons for the slow kinetics and high overpotential of water electrolysis. Therefore, the anode is the key to the electrocatalytic water splitting reaction. The development of low-cost, efficient, and stable anode materials is crucial for the large-scale commercialization of PEM.

[0004] Commercial anode catalysts include iridium oxide and ruthenium oxide. Among them, iridium oxide has attracted widespread attention from researchers because of its good activity and stability. CN117285088A discloses a method for preparing an iridium oxide cluster assembly, which shows excellent activity in acidic water electrolysis to produce hydrogen. However, when the catalyst slurry is directly physically sprayed, the catalytic layer easily falls off during the reaction, thereby affecting the stability of the catalyst. The solution strategy of most current technical solutions is to manufacture a loose and porous TiO2 layer and use the physical effect of the pores to suppress the shedding of the catalyst. For example, CN115992369A discloses a method for preparing a PEM hydrogen production anode catalyst layer, which uses sulfuric acid and a high-concentration H2O2 hot solution to treat a titanium plate, and then Ir is sintered on the titanium plate to solve problems such as the catalytic layer easily falling off.

[0005] However, existing technologies still cannot solve the above problems well, and the stability of the catalyst still needs to be improved. Summary of the Invention

[0006] In order to solve the above technical problems, the object of the present invention is to provide an in-situ grown PEMEC anode and a preparation method thereof, wherein the anode has good stability under high voltage.

[0007] To achieve the above object, the present invention provides a method for preparing an in-situ grown PEMEC anode, which comprises the following steps:

[0008] The Ti substrate is immersed in an etching reagent solution, and then taken out, cleaned and dried to obtain a Ti-F substrate; wherein the etching reagent is selected from one or a combination of two or more of ammonium fluoride, ammonium bifluoride, hydrofluoric acid, lithium fluoride, sodium fluoride, and potassium fluoride, and the concentration of the etching reagent solution is 0.01-0.1 mol / L, and the amount of the etching reagent solution is 35-40 mL of the etching reagent solution per 100 mg of the Ti substrate;

[0009] The Ti-F substrate is placed in an alkaline solution for hydrothermal reaction, and then taken out, cleaned and dried to obtain a Ti-OH substrate;

[0010] The metal source is coated on the surface of the Ti-OH substrate, and after drying and calcination, an in-situ grown PEMEC anode is obtained.

[0011] In the above preparation method, preferably, the Ti substrate is selected from one or a combination of two or more of Ti fiber felt, Ti mesh, Ti plate, and Ti particles.

[0012] In the above preparation method, preferably, the soaking time is 0.5-4h.

[0013] In the above preparation method, preferably, the alkaline solution is selected from one or a combination of two or more of sodium hydroxide, potassium hydroxide, ammonia water, lithium hydroxide, and tetrapropylammonium hydroxide.

[0014] In the above preparation method, preferably, the concentration of the alkaline solution is 0.1-2.0M, more preferably 0.5M.

[0015] In the above preparation method, preferably, the amount of the alkaline solution used is 30-40 mL per 100 mg of the Ti-F substrate.

[0016] In the above preparation method, preferably, the temperature of the hydrothermal reaction is 80-140° C., and the time is 6-24 hours.

[0017] In the above preparation method, preferably, the metal source is selected from one or a combination of two or more of iridium chloride, iridium nitrate, iridium acetylacetonate, chloroauric acid, chloroplatinic acid, and sodium chloropalladate. The metal source is prepared into a solution and applied to the surface of the Ti-OH substrate by drop coating or other methods.

[0018] In the above preparation method, preferably, the calcination temperature is 300-500° C. and the calcination time is 1-4 h.

[0019] The preparation method provided by the present invention uses an etching agent to remove the inert oxide layer on the surface of a Ti substrate. This is then combined with ion exchange in an alkaline environment to transform the Ti substrate surface into an active Ti-OH species. A metal source, such as Ir or Au, is then applied to the Ti substrate surface, dried, and calcined. This chemical bonding between the Ti and the metals, such as Ir and Au, is achieved, preventing the catalytic layer from falling off during the reaction and improving the stability of the PEM anode catalytic layer under high voltage.

[0020] The present invention also provides an in-situ grown PEMEC anode, which is prepared by the above preparation method.

[0021] According to a specific embodiment of the present invention, preferably, the active metal of the in situ grown PEMEC anode is a combination of iridium and gold. More preferably, the iridium loading is 0.15-0.4 mg / cm2 based on the area of the in situ grown PEMEC anode. 2 The gold loading is 0.4-0.6 mg / cm 2 .

[0022] The present invention also provides the use of the in-situ grown PEMEC anode in PEM hydrogen production.

[0023] The technical solution provided by this invention gently activates the titanium substrate and utilizes chemical bonding between the catalytic layer and the support to firmly secure the catalytic layer to the support, effectively preventing the catalytic layer from falling off. This strategy can also achieve the co-deposition of multiple metals (such as Ir-Au bimetallics), effectively improving the electron transfer efficiency at low Ir loadings. The resulting catalyst achieves excellent performance in PEM water electrolysis devices.

[0024] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0025] The present invention uses mild conditions to activate the carrier, converting the inert TiO2 film on the surface of the Ti substrate into an active Ti-OH species, thereby achieving chemical bonding between the Ti substrate carrier and the metal catalyst layer such as Ir and Au, enhancing the interaction between the carrier and the catalyst layer, and overcoming the problem that the anode catalyst layer falls off due to bubble or water flow impact during the hydrogen production process after traditional physical spraying, thereby effectively improving the stability of the anode. In addition, the technical solution of the present invention can use Au as an auxiliary metal to effectively reduce impedance and further improve the electrode OER activity; especially at extremely low Ir loading, the presence of Au enhances the conductive network of the electrode and improves the catalyst utilization rate. This strategy ensures high efficiency of electron transmission and uniform dispersion of Ir and Au metals, successfully solving the challenges of insufficient activity and stability of traditional low Ir loading electrodes, and effectively controlling the electrode cost. The preparation process of the in-situ grown PEMEC anode of the present invention is simple, has strong scalability and good application prospects in the field of PEM hydrogen production, and is worthy of promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 1 and 2 are SEM images of the Ti-OH mesh after hydrothermal treatment in Example 1 and the Ir-Ti mesh after Ir metal loading (Example 1A).

[0027] Figure 2 This is a SEM image of the in-situ grown electrode material after loading IrAu metal in Example 1 (Example 1B).

[0028] Figure 3 Polarization curve and ohmic impedance diagram of the in-situ grown anode titanium mesh electrode material prepared in Example 1 in the PEM test.

[0029] Figure 4 This is the polarization curve of the in-situ grown anode titanium mesh electrode material prepared in Example 2-3 in the PEM test. DETAILED DESCRIPTION

[0030] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be understood as limiting the scope of implementation of the present invention.

[0031] Example 1

[0032] This embodiment provides a method for preparing an in-situ grown PEMEC anode, which includes the following steps:

[0033] First, four 65 mg Ti meshes (2×2 cm, 200 mesh) were placed in 25 mL of 0.03 M NH4H2F solution, soaked at room temperature for 3 h, taken out and washed three times with distilled water, and dried in an oven at 60°C to obtain Ti-F meshes.

[0034] Secondly, the obtained Ti-F mesh was placed in 20 mL of 0.5 M NaOH solution, reacted under hydrothermal conditions at 130°C for 12 h, naturally cooled to room temperature, washed three times with distilled water, and dried in an oven at 60°C to obtain a Ti-OH mesh.

[0035] Next, 100 μL of a 30 mg Ir / mL IrCl3 solution was taken and distilled water was added to 0.5 mL to obtain a pure Ir solution (Example 1A, Example 1C). Then, 50 μL and 25 μL of a 30 mg Ir / mL IrCl3 solution were mixed with 33 μL and 50 μL of a 45 mg Au / mL HAuCl4 solution, respectively, to obtain AuIr mixed solutions with an Ir:Au ratio of 1:1 (Example 1B) and an Ir:Au ratio of 1:3 (Example 1D).

[0036] Finally, the above solution was drop-coated onto the surfaces of four Ti-OH meshes and dried in a 60°C oven. Afterwards, the temperature was raised to 400°C in a muffle furnace at a rate of 2°C / min and kept at that temperature for 3 h to obtain an in-situ grown anode titanium mesh electrode. Based on the surface area of the electrode, the iridium loading of the electrode was as follows: Example 1A Ir = 0.4 mg / cm 2 , Example 1B Ir=0.4mg / cm 2 , Example 1C Ir=0.2mg / cm 2 Example 1D Ir = 0.15 mg / cm 2 .

[0037] The catalyst morphology characteristics and performance results are as follows:

[0038] According to Example 1A ( Figure 1 ) and Example 1B ( Figure 2 ) shows that after hydrothermal treatment, a large number of nanoflower structures composed of two-dimensional nanosheets appeared on the surface of the Ti-OH network (see Figure 1 After coating the Ir solution and AuIr solution and calcining, it can be seen from the SEM image that the metal Ir and the metal AuIr are relatively uniformly loaded on the Ti mesh surface (see Figure 1 、 Figure 2 shown).

[0039] The in-situ grown anode titanium mesh electrode prepared in this example was applied to a PEM water electrolysis device (active area of 4 cm 2 ), a single-sided CCM coated with Pt / C catalyst was used on the cathode side, the test temperature was 80°C, and the water circulation flow rate at the anode was 50 mL / min. Figure 3The polarization curve and ohmic impedance results show that the mass activity of the electrode of Example 1A at 2 V reaches 3.65 A·cm -2 mg Ir -1 In Example 1B, the introduction of the second metal Au further improved the activity of the electrode. At a voltage of 2 V, the mass activity reached 5.78 A·cm -2 mg Ir -1 Compared with Example 1A, the activity increased by 58.4%. This may be due to the effective improvement of electron transfer efficiency by the introduction of Au. It is worth noting that at extremely low Ir loading, the presence of Au also effectively ensures electron transfer. The mass activity of the electrode of Example 1D at 2V is as high as 12.9A·cm -2 mg Ir -1 , compared with pure Ir Example 1C (2.12 A·cm -2 mg Ir -1 ), the activity increased by 5.1 times.

[0040] It can be seen from the above content that: at low Ir loading, the technical solution of Example 1 can still ensure the electron transmission efficiency of the electrode.

[0041] Example 2

[0042] This embodiment provides a method for preparing an in-situ grown PEMEC anode, which includes the following steps:

[0043] First, three 65 mg Ti meshes (2 × 2 cm, 200 mesh) were placed in 25 mL of NH₄H₂F solutions at concentrations of 0.03 M (2A), 0.01 M (2B), and 0.003 M (2C), respectively. The solutions were soaked at room temperature for 3 h, washed three times with distilled water, and dried in an oven at 60°C to obtain Ti-F meshes. The etching degrees of the Ti-F meshes were 10.8% (Example 2A), 1.1% (Example 2B), and 0% (Comparative Example 2C), respectively, where etching degree = (Ti mesh mass before etching - Ti mesh mass after etching) / Ti mesh mass before etching.

[0044] Secondly, the above Ti-F mesh was placed in 20 mL of 0.5 M NaOH solution and reacted under hydrothermal conditions at 130°C for 12 h. After naturally cooling to room temperature, it was washed three times with distilled water and dried in an oven at 60°C to obtain a Ti-OH mesh.

[0045] Next, 90 μL of 30 mg Ir / mL IrCl 3 solution and 68 μL of 40 mg Au / mL HAuCl 4 solution were taken, and distilled water was added to 0.5 mL to obtain an IrAu mixed solution with a mass ratio of Ir:Au = 1:1.

[0046] Finally, the IrAu mixed solution was drop-coated onto the surfaces of three Ti-OH meshes and dried in a 60°C oven. The temperature was then raised to 400°C in a muffle furnace at a rate of 2°C / min and maintained for 3 h to obtain an in-situ grown anode titanium mesh electrode. Based on the surface area of the electrode, the total AuIr loading on the electrode was 1.1 mg / cm 2 , Ir loading is 0.55 mg / cm 2 .

[0047] The in-situ grown anode titanium mesh electrode prepared in this example was applied to a PEM water electrolysis device (active area of 4 cm 2 ) were tested in the manner of reference example 1. Figure 4 The polarization curves shown show that the anode activity increases significantly with the increase of etching degree. At a voltage of 2V, the current of the titanium mesh electrode of Example 2A with an etching degree of 10.8% reaches 2.51A / cm 2 , compared with the unetched comparative example 2C (current of 1.84A / cm 2 ) compared to the previous period, it increased by 36.4%.

[0048] Example 3

[0049] This embodiment provides a method for preparing a PEMEC anode by in-situ growth of different auxiliary metals, which comprises the following steps:

[0050] First, three 65 mg Ti meshes (2×2 cm, 200 mesh) were placed in 25 mL of 0.03 M NH4H2F solution and soaked at room temperature for 3 h. They were then taken out, washed three times with distilled water, and dried in an oven at 60°C to obtain Ti-F meshes.

[0051] Secondly, the Ti-F mesh was placed in 20 mL of 0.5 M NaOH solution and reacted under hydrothermal conditions at 130°C for 12 h. After naturally cooling to room temperature, it was washed three times with distilled water and dried in an oven at 60°C to obtain a Ti-OH mesh.

[0052] Again, three 100 μL portions of IrCl3 solution with a concentration of 30 mg Ir / mL were mixed with 67 μL of Na2PdCl4 solution with a concentration of 45 mg Pd / mL, H2PtCl6 solution with a concentration of 45 mg Pt / mL, and HAuCl4 solution with a concentration of 45 mg Au / mL, and distilled water was added to 0.5 mL to obtain mixed solutions with mass ratios of Ir:Pd=1:1 (Example 3A), Ir:Pt=1:1 (Example 3B), and Ir:Au=1:1 (Example 3C), respectively.

[0053] Finally, the mixed solution was drop-coated onto the surfaces of three Ti-OH meshes and dried on a heating platform. The temperature was then raised to 400°C in a muffle furnace at a rate of 2°C / min and maintained for 3 hours to obtain two sets of in-situ grown anode titanium mesh electrodes. Based on the surface area of the electrodes, the total loading of the three sets of electrodes was 0.9 mg / cm 2 , 1.4mg / cm 2 and 0.9mg / cm 2 , Ir loading is 0.45 mg / cm 2 , 0.70mg / cm 2 , 0.45mg / cm 2 .

[0054] The titanium mesh anode electrode prepared in this example was applied to a PEM water electrolysis device (active area of 4 cm 2 ) were tested in the manner of reference example 1. Figure 4 The polarization curves shown in the figure show that the AuIr electrode exhibits the best performance. At a voltage of 2 V, the mass activity of the AuIr electrode reaches 5.5 A·cm -2 mg Ir -1 .

Claims

1. A method for preparing an in-situ grown PEMEC anode, comprising the following steps: The Ti substrate is immersed in an etching reagent solution at room temperature, and then removed, cleaned, and dried to obtain a Ti-F substrate; wherein the etching reagent is selected from ammonium bifluoride and / or hydrofluoric acid, the concentration of the etching reagent solution is 0.01-0.1 mol / L, and the amount of the etching reagent solution is 35-40 mL per 100 mg of the Ti substrate; The Ti-F substrate is placed in an alkaline solution for hydrothermal reaction, and then taken out, cleaned and dried to obtain a Ti-OH substrate; The metal source is coated on the surface of the Ti-OH substrate, dried and calcined to obtain an in-situ grown PEMEC anode; Wherein, the concentration of the alkaline solution is 0.1-2.0 M.

2. The preparation method according to claim 1, wherein The Ti substrate is selected from one or a combination of two or more of Ti fiber felt, Ti mesh, Ti plate, and Ti particles.

3. The preparation method according to claim 1, wherein The soaking time is 0.5-4 h.

4. The preparation method according to claim 1, wherein The alkaline solution is selected from one or a combination of two or more of sodium hydroxide, potassium hydroxide, ammonia water, lithium hydroxide, and tetrapropylammonium hydroxide.

5. The preparation method according to claim 1 or 4, wherein The concentration of the alkaline solution is 0.5 M.

6. The preparation method according to claim 1, wherein The hydrothermal reaction temperature is 80-140 ° C, and the time is 6-24 h.

7. The preparation method according to claim 1, wherein The metal source is selected from one or a combination of two or more of iridium chloride, iridium nitrate, iridium acetylacetonate, chloroauric acid, chloroplatinic acid, and sodium chloropalladate.

8. The preparation method according to claim 1, wherein The amount of the alkaline solution used is 30-40 mL per 100 mg of the Ti-F substrate.

9. An in-situ grown PEMEC anode prepared by the preparation method according to any one of claims 1 to 8.

10. The in-situ grown PEMEC anode according to claim 9, wherein: The active metal of the in situ grown PEMEC anode is a combination of iridium and gold.

11. The in situ grown PEMEC anode according to claim 10, wherein Based on the area of the in situ grown PEMEC anode, the iridium loading is 0.15-0.4 mg / cm 2 The gold loading is 0.4-0.6 mg / cm 2 .

12. Use of the in-situ grown PEMEC anode according to any one of claims 9 to 11 in PEM hydrogen production.

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