An anode porous transport electrode applied to a PEM electrolytic cell and a preparation method thereof

Abstract

This invention discloses a porous anode transport electrode for use in a PEM electrolyzer and its preparation method, comprising the following steps: S1, preparing a base coating on the surface of a porous transport layer substrate; S2, immersing the porous transport layer substrate loaded with the base coating in a metal precursor solution to form an initial transition layer; S3, subjecting the immersed porous transport layer substrate to a redox cyclic CVD treatment to form an alloyed transition layer with a preferred crystal plane; S4, preparing an anode catalyst layer on the surface of the alloyed transition layer by an electrodeposition process; S5, sintering the obtained porous anode transport electrode. In this invention, the redox cyclic CVD treatment forms an alloyed interface between the base coating and the initial transition layer, effectively improving the interlayer bonding strength; and the sintering treatment promotes interfacial atomic diffusion, making the catalyst layer less prone to detachment during long-term operation of the finally prepared electrode.

Description

Technical Field

[0001] This invention relates to the field of proton exchange membrane (PEM) electrolyzer core component preparation technology, and particularly to a porous anode transport electrode for use in PEM electrolyzers and its preparation method. Background Technology

[0002] Electrolysis of water for hydrogen production has seen rapid development as a core technology for clean hydrogen energy. Among these technologies, proton exchange membrane (PEM) electrolysis has become a key technological route in the field due to its advantages such as high operating current density, high purity of produced hydrogen, fast dynamic response, and adaptability to fluctuations in renewable energy. The membrane electrode assembly (MEA) is the core component of the PEM electrolyzer, and its performance directly determines the overall efficiency and operating cost of the electrolyzer.

[0003] Existing membrane electrode assemblies (MEAs) mainly consist of a proton exchange membrane, a cathode catalyst layer, an anode catalyst layer, a cathode gas diffusion layer, and an anode porous transport layer. Among these, the oxygen evolution reaction (OER) at the anode is kineticly slow, requiring the use of precious metals such as iridium and platinum, and their oxides, as catalysts. However, iridium and platinum are scarce and expensive, resulting in a high proportion of anode catalyst cost in the total MEA cost, becoming a key factor restricting the large-scale commercial application of PEM electrolyzers.

[0004] Currently, commercially available PEM electrolyzer membrane electrodes are generally prepared using the CCM method, where the catalyst layer is coated onto the proton exchange membrane. This method is complex and has limited room for microstructural control of the catalyst layer, thus having significant limitations in further improving catalytic performance and reducing noble metal loading. Compared to the CCM method, the CCS method, which prepares the catalyst layer on a porous transport layer, allows for more flexible control of the pore structure and interfacial bonding of the catalyst layer. This is beneficial for increasing the number of catalytic active sites and further reducing the loading of the noble metal Ir, and therefore has become an important development direction for porous transport electrode (PTE) technology.

[0005] In the fabrication process of porous transport electrodes (PTEs), magnetron sputtering and electrodeposition are two commonly used techniques for preparing catalytic layers. Magnetron sputtering produces anode catalytic layers with excellent adhesion to the substrate, but the resulting coating surface is smooth and flat, with a small number of catalytic active sites, leading to overall low catalytic performance. Furthermore, magnetron sputtering relies on physical bombardment to deposit target atoms onto the substrate surface, resulting in a lack of strong chemical bonds between coating atoms, easily forming atomic island structures and insufficient long-term stability. Electrodeposition, on the other hand, allows for controlled surface roughening, significantly increasing the active surface area and the number of active sites. However, the adhesion between the deposited metal and the substrate is weak, making the catalytic layer prone to detachment during long-term electrode operation, resulting in insufficient durability. Moreover, neither magnetron sputtering nor electrodeposition alone can achieve targeted control of specific crystal plane structures in the catalytic layer, making it difficult to further improve oxygen evolution reaction (OER) catalytic performance through crystal plane engineering.

[0006] To balance bonding strength and catalytic activity, existing technologies attempt to combine magnetron sputtering with electrodeposition. First, a substrate coating is prepared via magnetron sputtering, followed by electrodeposition to support the anode catalyst. However, existing methods still suffer from the following problems: the substrate coating formed by magnetron sputtering itself has weak interatomic bonding and an overly smooth surface. On the one hand, the bonding strength between the substrate and the substrate is insufficient; on the other hand, the smooth surface cannot provide enough nucleation anchors for subsequent electrodeposition, resulting in unsatisfactory bonding strength and structural uniformity of the electrodeposited catalyst layer. Furthermore, this approach still cannot achieve autonomous control of the crystal structure, making it difficult to simultaneously improve electrode performance at the levels of electron transport and intrinsic activity. Ultimately, this limits the overall improvement in the catalytic performance and durability of the porous transport electrode (PTE). Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art by providing a porous anode transport electrode for use in PEM electrolysis cells and its preparation method.

[0008] The objective of this invention is achieved through the following technical solution: a method for preparing a porous anode transport electrode for use in a PEM electrolytic cell, comprising the following steps: S1. A substrate coating is prepared on the surface of a porous transport layer substrate by magnetron sputtering. S2. The porous transport layer substrate loaded with the base coating is immersed in a metal precursor solution containing ionized target metal components. The target metal components in the metal precursor solution are anchored to defect sites on the surface of the base coating to form an initial transition layer. S3. The porous transport layer substrate after impregnation is subjected to oxidation-reduction cyclic CVD treatment. By alternating surface reconstruction under an oxidizing atmosphere and interface reaction under a reducing atmosphere, grain boundary migration and rearrangement are driven to form an alloyed transition layer with preferred crystal planes. S4. An anode catalyst layer is prepared on the surface of the alloyed transition layer by electrodeposition process to obtain a porous anode transport electrode. S5. The obtained porous anode transmission electrode is sintered.

[0009] Preferably, the porous transport layer substrate is selected from any one of titanium fiber felt, titanium woven mesh, and porous titanium mesh; the base coating material is selected from any one of platinum, iridium, and titanium. In step S1, the parameters of the magnetron sputtering process are: sputtering power of 50-100W and deposition time of 3-30min.

[0010] Preferably, in step S2, the target metal component in the metal precursor solution matches the metal component in the substrate coating and the anode catalyst layer; The solvent of the metal precursor solution is water, and the solute of the metal precursor solution is selected from one or more of iridium acetate, iridium chloride, platinum chloride, ruthenium chloride, titanium chloride, nickel chloride, iridium acetylacetone, chloroplatinic acid, or nickel chloride.

[0011] Preferably, in step S2, the temperature of the impregnation treatment is 25℃-90℃, and a nitrogen atmosphere, hydrogen atmosphere or air atmosphere is maintained during the impregnation process, with an impregnation time of 2-11h.

[0012] Preferably, in step S3, the specific method of the redox cyclic CVD treatment is as follows: the porous transport layer substrate after impregnation is placed in the CVD reaction chamber, the CVD reaction chamber is heated to a preset temperature range, oxygen is alternately introduced for surface oxidation reconstruction, and hydrogen is introduced for reduction reaction, and the cycle is repeated multiple times, with the last cycle ending in a hydrogen reduction atmosphere.

[0013] Preferably, in step S3, when performing redox cyclic CVD treatment, the CVD reaction chamber is heated to 200-500°C at a heating rate of 5°C / min. When introducing oxygen, the oxygen introduction rate is 5-15 mL / min, and the holding time is 5-10 min; When introducing hydrogen gas, the introduction rate is 8-60 mL / min, and the holding time is 8-15 min. Each cycle consists of introducing oxygen once and hydrogen once, and a total of 10-40 cycles are performed.

[0014] As a preferred option, in step S3, the preferred crystal plane is the (111) crystal plane, and the intercepts on the three crystal axes x, y, and z are all 1 lattice constant unit.

[0015] Preferably, in step S4, the electrodeposition is performed using any one of the following methods: constant voltage method, constant current method, cyclic voltammetry method, or pulse electrodeposition method.

[0016] Preferably, the metal component of the anode catalyst layer is any one of iridium, a combination of iridium and ruthenium, a combination of iridium and nickel, a combination of ruthenium and nickel, or a combination of iridium and platinum; The electrodeposition solution contains a metal salt, a complexing agent, and an oxidizing agent corresponding to the metal component; the complexing agent is selected from at least one of ethylenediaminetetraacetic acid, disodium ethylenediaminetetraacetic acid, ammonia, oxalic acid, and phosphoric acid; the oxidizing agent is selected from at least one of potassium acetate, potassium carbonate, potassium borate, potassium phosphate, sodium bicarbonate, potassium permanganate, potassium dichromate, and hydrogen peroxide.

[0017] A porous anode transport electrode for use in a PEM electrolyzer includes: Porous transport layer substrate; A substrate coating is disposed on the surface of a porous transport layer substrate, and the substrate coating is prepared by magnetron sputtering. An alloyed transition layer is set on the surface of the substrate coating. The alloyed transition layer is obtained by anchoring the defect sites on the surface of the substrate coating with a metal precursor and then performing a redox cyclic CVD treatment. The alloyed transition layer has a preferred crystal plane. Electrodeposited anode catalyst layer disposed on the surface of alloyed transition layer.

[0018] The beneficial effects of this invention are: 1. In the impregnation process of this invention, the target metal component (metal ions) in the metal precursor solution preferentially anchors to the high-energy defect sites of the magnetron sputtering substrate coating, forming a strong interaction with the coordination unsaturated atoms at the defect sites, filling the "atom island" structural defects generated by the magnetron sputtering process, thereby improving the cohesive strength of the substrate coating itself.

[0019] 2. In this invention, the redox cyclic CVD process drives grain boundary migration and rearrangement through thermodynamics, forming an alloyed interface between the substrate coating and the initial transition layer. This transforms the weak physical bombardment bonding into strong chemical bonding, effectively improving the interlayer bonding strength. The final sintering process further promotes interfacial atomic diffusion, enhancing the bonding force between different layers. This results in the electrode being less prone to catalyst layer detachment during long-term operation, exhibiting durability far superior to products prepared by single magnetron sputtering or electrodeposition processes.

[0020] 3. After redox cyclic CVD treatment, a large number of nucleation sites are formed on the surface of the alloyed transition layer, providing sufficient growth anchors for subsequent electrodeposition. This results in a rough, porous, and high specific surface area particle distribution structure in the electrodeposited catalytic layer, significantly increasing the number of catalytic active sites.

[0021] 4. The preferred crystal plane ((111) crystal plane) formed by the induced grain boundary migration and rearrangement through redox cyclic CVD treatment will form an alloyed chemical bonding interface between the base coating and the transition coating, replacing the original physical bonding of magnetron sputtering, effectively improving the interlayer bonding force and avoiding the shedding of the anode catalyst layer during long-term electrolysis; at the same time, the (111) crystal plane is more conducive to electron transfer and reactant adsorption in the oxygen evolution reaction process, improving the intrinsic catalytic efficiency of a single active site at the atomic level. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the porous anode transmission electrode of the present invention.

[0023] Figure 2 This is a characterization diagram of the morphology and structure of a porous transport layer substrate after magnetron sputtering and coating onto a platinum substrate.

[0024] Figure 3 This is a characterization diagram of the morphology and structure of the porous transport layer substrate after impregnation and redox cycling in Embodiment 1 of the present invention.

[0025] Figure 4 This is a characterization diagram of the morphology and structure after electrodeposition and sintering in Example 1 of the present invention.

[0026] Figure 5 The polarization curve is a performance test graph of the porous anode transport electrode prepared in Example 1 of the present invention.

[0027] Figure 6 This is a characterization diagram of the morphology and structure after electrodeposition and sintering in Example 2 of the present invention.

[0028] Figure 7 The polarization curve is a performance test graph of the porous anode transport electrode prepared in Example 2 of the present invention.

[0029] Figure 8 This is a characterization diagram of the morphology and structure of the porous transport layer substrate after magnetron sputtering of an iridium substrate coating in Embodiment 3 of the present invention.

[0030] Figure 9 This is a characterization diagram of the morphology and structure after electrodeposition and sintering in Example 3 of the present invention.

[0031] Figure 10 The polarization curve is a performance test graph of the porous anode transport electrode prepared in Example 3 of the present invention.

[0032] Figure 11 The polarization curve is a performance test graph of the porous anode transport electrode prepared in Example 4 of the present invention.

[0033] Figure 12 The polarization curve is a performance test graph of the porous anode transport electrode prepared in Example 5 of the present invention. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0035] Those skilled in the art should understand that, in the disclosure of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limiting this invention.

[0036] It is understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "a" should not be understood as a limitation on the number.

[0037] like Figure 1 As shown, a method for preparing a porous anode transport electrode for use in a PEM electrolyzer includes the following steps: S1. A base coating is prepared on the surface of a porous transport layer substrate by magnetron sputtering.

[0038] S2. The porous transport layer substrate loaded with the base coating is immersed in a metal precursor solution containing ionized target metal components. The target metal components in the metal precursor solution are anchored to defect sites on the surface of the base coating to form an initial transition layer.

[0039] S3. The porous transport layer substrate after impregnation is subjected to oxidation-reduction cyclic CVD treatment. By alternating surface reconstruction under an oxidizing atmosphere and interface reaction under a reducing atmosphere, grain boundary migration and rearrangement are driven to form an alloyed transition layer with preferred crystal planes.

[0040] S4. An anode catalyst layer is prepared on the surface of the alloyed transition layer by electrodeposition process to obtain a porous anode transport electrode.

[0041] S5. The obtained porous anode transmission electrode is sintered.

[0042] This invention addresses the problems of existing porous anodic transport electrodes (PTEs) in that "it is difficult to balance the bonding force and catalytic activity, and the crystal structure cannot be directionally controlled". It adopts a synergistic process step of "magnetron sputtering for priming - impregnation for defect anchoring - redox cyclic CVD crystal surface reconstruction - electrodeposition of loaded catalytic layer - sintering for strengthening", which effectively solves the problems existing in existing porous anodic transport electrodes (PTEs).

[0043] In step S2, during the impregnation process, the target metal component (metal ions) in the metal precursor solution preferentially anchors to the high-energy defect sites of the magnetron sputtering substrate coating, forming strong interactions with the coordinated unsaturated atoms at the defects. This fills the "atomic island" structural defects generated by the magnetron sputtering process, thereby enhancing the cohesive strength of the substrate coating itself. In step S3, the redox cyclic CVD process thermodynamically drives grain boundary migration and rearrangement, forming an alloying interface between the substrate coating and the initial transition layer. This transforms the originally weak physical bombardment bonding into strong chemical bonding, effectively improving the interlayer bonding strength. The final sintering process further promotes interfacial atomic diffusion, strengthening the bonding force between different layers. This results in the final electrode having a catalyst layer that is less prone to detachment during long-term operation, exhibiting durability far superior to products prepared by single magnetron sputtering or electrodeposition processes.

[0044] After redox cyclic CVD treatment, a large number of nucleation sites are formed on the surface of the alloyed transition layer, providing sufficient growth anchors for subsequent electrodeposition. This results in a rough, porous, and high specific surface area particle distribution structure in the electrodeposited catalytic layer, significantly increasing the number of catalytic active sites.

[0045] The porous transport layer substrate is selected from any one of titanium fiber felt, titanium woven mesh, and porous titanium mesh; the base coating material is selected from any one of platinum, iridium, and titanium.

[0046] In step S1, the parameters of the magnetron sputtering process are: sputtering power of 50-100W and deposition time of 3-30min.

[0047] Before preparing the base coating, the porous transport layer substrate is first subjected to plasma cleaning.

[0048] In step S2, the target metal component in the metal precursor solution is matched with the metal components in the substrate coating and the anode catalyst layer. During the impregnation process, the target metal component (metal ions) homologous to the substrate coating has a higher chemical affinity with the coordinated unsaturated atoms at the defects on the substrate coating surface, which can form stronger interatomic interactions, achieve firm anchoring of defect sites, and fill the "atomic island" structural defects of the magnetron sputtering substrate coating.

[0049] During the redox cyclic CVD treatment and sintering stages, the diffusion barrier of metal atoms of the same type is lower, making it easier for grain boundary migration and interfacial interdiffusion to occur, forming a continuous alloying transition interface. This can transform the weak bonding of the original physical deposition by magnetron sputtering into strong metallic bonding. At the same time, the transition layer and the subsequent anode catalyst layer are of the same metal composition, and the catalyst layer can be epitaxially grown on the surface of the transition layer, avoiding the risk of interface peeling of heterogeneous materials. Ultimately, a strong bond is achieved between the "substrate coating - alloying transition layer - anode catalyst layer", making the catalyst layer less prone to detachment during long-term operation of the electrode and significantly improving its durability.

[0050] Specifically, the solvent of the metal precursor solution is water, and the solute of the metal precursor solution is selected from one or more of iridium acetate, iridium chloride, platinum chloride, ruthenium chloride, titanium chloride, nickel chloride, iridium acetylacetonate, chloroplatinic acid, or nickel chloride.

[0051] The immersion temperature is 25℃-90℃, and a nitrogen atmosphere, hydrogen atmosphere or air atmosphere is maintained during the immersion process. The immersion time is 2-11 hours.

[0052] In step S3, a preferred crystal plane structure can be formed through directional grain boundary reconstruction by redox cyclic CVD. The preferred crystal plane is the (111) crystal plane, with intercepts of 1 lattice constant unit on the x, y, and z crystal axes. This (111) crystal plane is the closest-packed crystal plane in the face-centered cubic (FCC) crystal structure.

[0053] The preferred crystal plane ((111) crystal plane) formed by the induced grain boundary migration and rearrangement through redox cyclic CVD treatment will form an alloyed chemical bonding interface between the base coating and the transition coating, replacing the original physical bonding of magnetron sputtering, effectively improving the interlayer bonding force and avoiding the shedding of the anode catalyst layer during long-term electrolysis.

[0054] Meanwhile, the (111) crystal facet is more conducive to electron transfer and reactant adsorption during the oxygen evolution reaction (OER), improving the intrinsic catalytic efficiency of individual active sites at the atomic level. For the oxygen evolution reaction (OER) of the PEM electrolyzer anode, the (111) crystal facet has the highest atomic density, and its adsorption energy for reaction intermediates is closer to the optimal value. Its intrinsic catalytic activity is higher than that of other crystal facet structures such as the (100) and (110) crystal faces. At the same time, the close-packed crystal facet has stronger chemical stability, which can improve the durability of the electrode during long-term operation.

[0055] The specific method of oxidation-reduction cyclic CVD treatment is as follows: the porous transport layer substrate after impregnation is placed in the CVD reaction chamber, the CVD reaction chamber is heated to a preset temperature range, oxygen is alternately introduced for surface oxidation reconstruction, and hydrogen is introduced for reduction reaction. The cycle is repeated multiple times, and the last cycle ends in a hydrogen reduction atmosphere.

[0056] Specifically, during the redox cyclic CVD process, the CVD reaction chamber is heated to 200-500℃ at a heating rate of 5℃ / min; when oxygen is introduced, the oxygen introduction rate is 5-15mL / min, and the holding time is 5-10min; when hydrogen is introduced, the hydrogen introduction rate is 8-60mL / min, and the holding time is 8-15min; one cycle of oxygen introduction and one cycle of hydrogen introduction constitute one cycle unit, and a total of 10-40 cycle units are performed.

[0057] In step S4, electrodeposition is performed using any one of the following methods: constant voltage method, constant current method, cyclic voltammetry method, or pulse electrodeposition method.

[0058] When using the constant voltage method, the applied constant voltage is 0.35-0.9V vs. SCE (meaning that when using a saturated calomel electrode as a reference electrode, the potential of the working electrode is 0.35-0.9V), and the deposition time is 5-100min; When using the constant current method, the applied constant current density is 6-25 mA / cm², and the deposition time is 5-100 min. When using the cyclic voltammetry method, the applied voltage range is -0.5 to 0.8V vs. SCE, and the number of cycles is 20 to 500. When using the pulse electrodeposition method, one cycle consists of applying a 0.6V vs. SCE voltage for 30 seconds and then applying a 0V vs. SCE voltage for 10 seconds, for a total of 300-500 cycles.

[0059] The metal composition of the anode catalyst layer is any one of iridium, a combination of iridium and ruthenium, a combination of iridium and nickel, a combination of ruthenium and nickel, or a combination of iridium and platinum.

[0060] The electrodeposition solution contains a metal salt, a complexing agent, and an oxidizing agent corresponding to the metal component; the complexing agent is selected from at least one of ethylenediaminetetraacetic acid (EDTA), disodium ethylenediaminetetraacetic acid (EDTA-2Na), ammonia, oxalic acid, and phosphoric acid; the oxidizing agent is selected from at least one of potassium acetate, potassium carbonate, potassium borate, potassium phosphate, sodium bicarbonate, potassium permanganate, potassium dichromate, and hydrogen peroxide.

[0061] When preparing the plating solution, first weigh a certain weight of metal salt (such as chloroiridium acid, iridium chloride, ruthenium chloride, chloroplatinic acid, or nickel chloride, etc.) and complex, and add a small amount of pure water to the complex and metal salt. Then add a certain amount of oxidant, and then prepare a certain amount of pH buffer solution, and slowly add it to the above solution. Make up the volume and stir. The stirring speed is 50-5000 rpm and the stirring time is 8-100 hours.

[0062] In step S5, the sintering process is carried out in a vacuum atmosphere, an inert gas atmosphere, or an air atmosphere. A porous anode transport electrode for use in a PEM electrolytic cell includes: Porous transport layer substrate; A substrate coating is disposed on the surface of a porous transport layer substrate, and the substrate coating is prepared by magnetron sputtering. An alloyed transition layer is set on the surface of the substrate coating. The alloyed transition layer is obtained by anchoring the defect sites on the surface of the substrate coating with a metal precursor and then performing a redox cyclic CVD treatment. The alloyed transition layer has a preferred crystal plane. Electrodeposited anode catalyst layer disposed on the surface of alloyed transition layer.

[0063] Example 1: 1) First, the porous transport layer substrate is plasma cleaned, and then the substrate coating is sputtered by magnetron sputtering. The target material is a platinum (Pt) target, the sputtering power is 100W, and the deposition time is 10min.

[0064] 2) Preparation of metal precursor solution: Weigh 0.01-0.02g chloroplatinic acid and 0.01-0.02g iridium chloride, add a small amount of pure water, place the porous transport layer substrate with substrate coating in the metal precursor solution for 5-10h, heat to 60-80℃ in a sealed nitrogen atmosphere, and take it out after drying.

[0065] 3) Place the impregnated porous transport layer substrate into the CVD reaction chamber and heat it to 300-400℃ at a heating rate of 5℃ / min. Introduce oxygen at a rate of 5-10ml / min and maintain for 5-8min. Then switch the hydrogen valve and introduce hydrogen at a rate of 10-30ml / min and maintain for 10-15min. Repeat this cycle 10-20 times. The last cycle is in a hydrogen atmosphere. After cooling, remove the substrate.

[0066] 4) Weigh 0.2-0.5g of chloroplatinic acid and 0.3-0.5g of oxalic acid, add a small amount of pure water, add 0.1-0.4g of potassium permanganate, weigh 1-2g of sodium bicarbonate and dissolve it in pure water. Slowly guide the sodium bicarbonate solution into the previous solution and bring the volume to 60mL to obtain the plating solution. Stir the plating solution for 36 hours. Clamp the porous transport layer substrate with the alloyed transition layer in an electrode clamp and insert it into the previous plating solution. Apply a constant voltage of 0.8V vs. SCE and deposit for 15 minutes to obtain the anode porous transport electrode.

[0067] 5) The porous anode transport electrode is further sintered in a nitrogen atmosphere.

[0068] Figure 2 The image shows the morphology and structure of the porous transport layer substrate after magnetron sputtering platinum substrate coating in Embodiment 1 of the present invention. It can be seen that there is a discontinuous structure in the platinum substrate coating.

[0069] Figure 3 The image shows the morphological structure of the porous transport layer substrate after impregnation and redox cycling in Example 1 of the present invention. It can be seen that there are nucleation sites in the alloyed transition layer, which provide more anchor points for the next electrodeposition step.

[0070] Figure 4 This is a characterization image of the morphology and structure after electrodeposition and sintering in Example 1 of the present invention. The porous anode transport electrode prepared in Example 1, as determined by ICP testing, has an iridium loading of 0.2-0.3 mg / cm², significantly lower than the Ir loading of commercially available membrane electrodes. When assembled into a membrane electrode assembly (MEA) and subjected to atmospheric pressure fixture testing, its performance is as follows... Figure 5 As shown, the current density at 1.8V and 75℃ is 2.3A / cm². 2 .

[0071] Example 2: 1) First, the porous transport layer substrate is plasma cleaned, and then the substrate coating is sputtered by magnetron sputtering. The target material is a platinum (Pt) target, the sputtering power is 50W, and the deposition time is 5min.

[0072] 2) Preparation of metal precursor solution: Weigh 0.02-0.05g of iridium acetate and 0.01-0.02g of ruthenium chloride, add a small amount of pure water, place the porous transport layer substrate with the base coating in the metal precursor solution for 3-8h, heat to 60-80℃ in a sealed nitrogen atmosphere, and take it out after drying.

[0073] 3) Place the impregnated porous transport layer substrate into the CVD reaction chamber and heat it to 300-400℃ at a heating rate of 5℃ / min. Introduce oxygen at a rate of 5-8ml / min and maintain for 5-8min. Then switch the hydrogen valve and introduce hydrogen at a rate of 8-10ml / min and maintain for 8-10min. Repeat this cycle 20-30 times. The last cycle is in a hydrogen atmosphere. After cooling, remove the substrate.

[0074] 4) Weigh 0.1-0.3g iridium chloride, 0.1-0.2g ruthenium chloride, and 0.2-0.6g ethylenediaminetetraacetic acid (EDTA). Add a small amount of pure water and 0.5-2mL of 30% hydrogen peroxide. Weigh 1-2g of anhydrous potassium borate and dissolve it in pure water. Slowly pour the potassium borate solution into the previous solution and bring the volume to 50mL to obtain the plating solution. Stir the plating solution for 50 hours. Clamp the porous transport layer substrate with the alloyed transition layer onto an electrode clamp and immerse it in the previous plating solution, applying a constant current of 10mA / cm. 2 The deposition time was 25 min. A porous anode transport electrode was obtained.

[0075] 5) The porous anode transport electrode is further sintered in a nitrogen atmosphere.

[0076] Figure 6 This is a characterization image of the morphology and structure after electrodeposition and sintering in Example 2 of the present invention. The porous anode transport electrode prepared in Example 2, as determined by ICP testing, has an iridium loading of 0.3-0.5 mg / cm² and a ruthenium loading of 0.1-0.2 mg / cm². 2 The iridium and ruthenium loadings are significantly lower than those in commercially available membrane electrodes. When assembled into a membrane electrode assembly (MEA) and subjected to atmospheric pressure fixture testing, its performance was as follows: Figure 7 As shown, the current density is 2.15 A / cm2 at 75℃ and 1.8V.

[0077] Example 3: 1) First, the porous transport layer substrate is plasma cleaned, and then the substrate coating is sputtered by magnetron sputtering. The target material is an iridium (Ir) target, the sputtering power is 80W, and the deposition time is 8min.

[0078] 2) Preparation of metal precursor solution: Weigh 0.01-0.03g of iridium acetylacetone and 0.03-0.05g of nickel chloride, add a small amount of pure water, place the porous transport layer substrate with the substrate coating in the metal precursor solution for 6-11h, heat to 30-50℃ in a sealed nitrogen atmosphere, and take it out after drying.

[0079] 3) Place the impregnated porous transport layer substrate into the CVD reaction chamber and heat it to 300-400℃ at a heating rate of 5℃ / min. Introduce oxygen at a rate of 4-10ml / min and maintain for 8-10min. Then switch the hydrogen valve and introduce hydrogen at a rate of 12-18ml / min and maintain for 8-12min. Repeat this cycle 15-20 times. The last cycle is in a hydrogen atmosphere. After cooling, remove the substrate.

[0080] 4) Weigh 0.15-0.3g of chloroiridium acid, 0.2-0.35g of nickel chloride, and 0.3-0.5g of oxalic acid. Add a small amount of pure water and 3-5mL of 30% hydrogen peroxide. Weigh 3-4g of anhydrous potassium carbonate and dissolve it in pure water. Slowly pour the potassium carbonate solution into the previous solution and bring the volume to 100mL to obtain the plating solution. Stir the plating solution for 100 hours. Clamp the porous transport layer substrate with the alloyed transition layer in an electrode clamp and insert it into the previous plating solution. Apply a voltage range of -0.4-0.05V vs. SCE for 300 cycles to obtain the anode porous transport electrode.

[0081] 5) The porous anode transport electrode is further sintered in a nitrogen atmosphere.

[0082] Figure 8 This is a characterization image of the morphology and structure of the porous transport layer substrate after magnetron sputtering iridium substrate coating in Embodiment 3 of the present invention. Figure 9This is a characterization diagram of the morphology and structure after electrodeposition and sintering in Example 3 of the present invention.

[0083] The porous anode transport electrode prepared in Example 3 had an iridium loading of 0.15-0.25 mg / cm³ as determined by ICP testing. 2 This is significantly lower than the iridium loading of commercially available membrane electrodes. When assembled into a membrane electrode assembly (MEA) and subjected to atmospheric pressure fixture testing, its performance was as follows: Figure 10 As shown, the current density at 1.8V and 75℃ is 2.14A / cm². 2 .

[0084] Example 4: 1) First, the porous transport layer substrate is plasma cleaned, and then the substrate coating is sputtered by magnetron sputtering. The target material is an iridium (Ir) target, the sputtering power is 50W, and the deposition time is 5min.

[0085] 2) Preparation of metal precursor solution: Weigh 0.02-0.05g iridium acetate and 0.01-0.02g ruthenium chloride, add a small amount of pure water, place the porous transport layer substrate with the base coating in the metal precursor solution for 3-8h, heat to 60-80℃ in a sealed nitrogen atmosphere, and take it out after drying.

[0086] 3) Place the impregnated porous transport layer substrate into the CVD reaction chamber and heat it to 300-400℃ at a heating rate of 5℃ / min. Introduce oxygen at a rate of 5-10ml / min and maintain for 5-8min. Then switch the hydrogen valve and introduce hydrogen at a rate of 10-30ml / min and maintain for 10-15min. Repeat this cycle 10-20 times. The last cycle is in a hydrogen atmosphere. After cooling, remove the substrate.

[0087] 4) Weigh 0.1-0.3g iridium chloride, 0.1-0.2g ruthenium chloride, and 0.2-0.6g EDTA. Add a small amount of pure water, 3-5mL of 30% hydrogen peroxide, and 1-2g of anhydrous potassium borate dissolved in pure water. Slowly pour the potassium borate solution into the previous solution and bring the volume to 50mL to obtain the plating solution. Stir the plating solution for 50 hours. Clamp the porous transport layer substrate with the alloyed transition layer onto an electrode clamp and immerse it in the previous plating solution, applying a constant current of 10mA / cm. 2 The deposition time was 25 min, and a porous anode transport electrode was obtained.

[0088] 5) The porous anode transport electrode is further sintered in a nitrogen atmosphere.

[0089] The porous anode transport electrode prepared in Example 4 had an iridium loading of 0.06-0.4 mg / cm³ as determined by ICP testing. 2This is significantly lower than the iridium loading of commercially available membrane electrodes. When assembled into a membrane electrode assembly (MEA) and subjected to atmospheric pressure fixture testing, its performance was as follows: Figure 11 As shown, the current density at 1.8V and 75℃ is 2.07A / cm². 2 .

[0090] Example 5: 1) First, the porous transport layer substrate is plasma cleaned, and then the substrate coating is sputtered by magnetron sputtering. The target material is titanium (Ti) target, the sputtering power is 100W, and the deposition time is 15min.

[0091] 2) Preparation of metal precursor solution: 0.01-0.02g chloroplatinic acid, 0.01-0.02g iridium chloride and 0.02-0.03g titanium chloride, add a small amount of pure water, place the porous transport layer substrate with substrate coating in the metal precursor solution for 2-5 hours, heat to 50-90℃ in a sealed nitrogen atmosphere, and take it out after drying.

[0092] 3) Place the impregnated porous transport layer substrate into the CVD reaction chamber and heat it to 400-500℃ at a heating rate of 5℃ / min. Introduce oxygen at a rate of 10-15ml / min and maintain for 5-10min. Then switch the hydrogen valve and introduce hydrogen at a rate of 40-60ml / min and maintain for 10-15min. Repeat this cycle 20-40 times. The last cycle is in a hydrogen atmosphere. After cooling, remove the substrate.

[0093] 4) Weigh 0.1-0.2g iridium chloride, 0.2-0.4g chloroplatinic acid, and 0.1-0.2mL ammonia water. Add pure water and 2-4g potassium dichromate. Weigh 3-5g anhydrous potassium acetate and dissolve it in pure water. Slowly pour the potassium acetate solution into the previous solution and bring the volume to 80mL to obtain the plating solution. Stir the plating solution for 60 hours. Clamp the porous transport layer substrate with the alloyed transition layer in an electrode clamp and insert it into the previous plating solution. Apply a banded voltage of 0.6V vs. SCE for 30s, then 0V vs. SCE for 10s, repeating 300-500 times to obtain the anode porous transport electrode.

[0094] 5) The porous anode transport electrode is further sintered in a nitrogen atmosphere.

[0095] The porous anode transport electrode prepared in Example 5 had an iridium loading of 0.1-0.5 mg / cm³ as determined by ICP testing. 2 This is significantly lower than the iridium loading of commercially available membrane electrodes. When assembled into a membrane electrode assembly (MEA) and subjected to atmospheric pressure fixture testing, its performance was as follows: Figure 12 As shown, the current density at 1.8V and 75℃ is 2.4A / cm². 2 .

[0096] This invention is not limited to the preferred embodiments described above. Anyone can derive other products in various forms under the guidance of this invention. However, regardless of any changes in shape or structure, any technical solution that is the same as or similar to this application falls within the protection scope of this invention.

Claims

1. A method for preparing a porous anode transport electrode for use in a PEM electrolytic cell, characterized in that, Includes the following steps: S1. A substrate coating is prepared on the surface of a porous transport layer substrate by magnetron sputtering. S2. The porous transport layer substrate loaded with the base coating is immersed in a metal precursor solution containing ionized target metal components. The target metal components in the metal precursor solution are anchored to defect sites on the surface of the base coating to form an initial transition layer. S3. The porous transport layer substrate after impregnation is subjected to oxidation-reduction cyclic CVD treatment. By alternating surface reconstruction under an oxidizing atmosphere and interface reaction under a reducing atmosphere, grain boundary migration and rearrangement are driven to form an alloyed transition layer with preferred crystal planes. S4. An anode catalyst layer is prepared on the surface of the alloyed transition layer by electrodeposition process to obtain a porous anode transport electrode. S5. The obtained porous anode transmission electrode is sintered.

2. The method for preparing the porous anode transport electrode for use in a PEM electrolytic cell according to claim 1, characterized in that, The porous transport layer substrate is selected from any one of titanium fiber felt, titanium woven mesh, and porous titanium mesh; the base coating material is selected from any one of platinum, iridium, and titanium. In step S1, the parameters of the magnetron sputtering process are: sputtering power of 50-100W and deposition time of 3-30min.

3. The method for preparing the porous anode transport electrode for use in a PEM electrolytic cell according to claim 1, characterized in that, In step S2, the target metal component in the metal precursor solution is matched with the metal components in the substrate coating and the anode catalyst layer; The solvent of the metal precursor solution is water, and the solute of the metal precursor solution is selected from one or more of iridium acetate, iridium chloride, platinum chloride, ruthenium chloride, titanium chloride, nickel chloride, iridium acetylacetone, chloroplatinic acid, or nickel chloride.

4. The method for preparing the porous anode transport electrode for use in a PEM electrolytic cell according to claim 1, characterized in that, In step S2, the immersion temperature is 25℃-90℃, and a nitrogen atmosphere, hydrogen atmosphere or air atmosphere is maintained during the immersion process. The immersion time is 2-11h.

5. The method for preparing the porous anode transport electrode for use in a PEM electrolytic cell according to claim 1, characterized in that, In step S3, the specific method of the redox cyclic CVD treatment is as follows: the porous transport layer substrate after impregnation is placed in the CVD reaction chamber, the CVD reaction chamber is heated to a preset temperature range, oxygen is alternately introduced for surface oxidation reconstruction, and hydrogen is introduced for reduction reaction. The cycle is repeated multiple times, and the last cycle ends in a hydrogen reduction atmosphere.

6. The method for preparing the porous anode transport electrode for use in a PEM electrolytic cell according to claim 5, characterized in that, In step S3, when performing redox cyclic CVD treatment, the CVD reaction chamber is heated to 200-500℃ at a heating rate of 5℃ / min. When introducing oxygen, the oxygen introduction rate is 5-15 mL / min, and the holding time is 5-10 min; When introducing hydrogen gas, the introduction rate is 8-60 mL / min, and the holding time is 8-15 min. Each cycle consists of introducing oxygen once and hydrogen once, and a total of 10-40 cycles are performed.

7. The method for preparing the porous anode transport electrode for use in a PEM electrolytic cell according to claim 1, characterized in that, In step S3, the preferred crystal plane is the (111) crystal plane, and the intercepts on the three crystal axes x, y, and z are all 1 lattice constant unit.

8. The method for preparing the porous anode transport electrode for use in a PEM electrolytic cell according to claim 1, characterized in that, In step S4, the electrodeposition is performed using any one of the following methods: constant voltage method, constant current method, cyclic voltammetry method, or pulse electrodeposition method.

9. The method for preparing the porous anode transport electrode for use in a PEM electrolytic cell according to claim 1, characterized in that, The metal component of the anode catalyst layer is any one of iridium, a combination of iridium and ruthenium, a combination of iridium and nickel, a combination of ruthenium and nickel, or a combination of iridium and platinum; The electrodeposition solution contains a metal salt, a complexing agent, and an oxidizing agent corresponding to the metal component; the complexing agent is selected from at least one of ethylenediaminetetraacetic acid, disodium ethylenediaminetetraacetic acid, ammonia, oxalic acid, and phosphoric acid; the oxidizing agent is selected from at least one of potassium acetate, potassium carbonate, potassium borate, potassium phosphate, sodium bicarbonate, potassium permanganate, potassium dichromate, and hydrogen peroxide.

10. A porous anode transport electrode for use in a PEM electrolytic cell, characterized in that, include: Porous transport layer substrate; A substrate coating is disposed on the surface of a porous transport layer substrate, and the substrate coating is prepared by magnetron sputtering. An alloyed transition layer is set on the surface of the substrate coating. The alloyed transition layer is obtained by anchoring the defect sites on the surface of the substrate coating with a metal precursor and then performing a redox cyclic CVD treatment. The alloyed transition layer has a preferred crystal plane. Electrodeposited anode catalyst layer disposed on the surface of alloyed transition layer.

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