A dual-site supported noble metal catalyst, and a preparation method and application thereof

Abstract

The application provides a dual-site supported noble metal catalyst and a preparation method and application thereof, and relates to the technical field of proton exchange membrane water electrolysis. The dual-site supported noble metal catalyst comprises noble metal oxides and surface hydroxyl-rich hydrophilic oxides coated in the noble metal oxides. The application splits the ionomer adsorption site and the active site by constructing the anode catalyst structure of dual-site synergistic reaction, improves the exposure of the active site, constructs a stable proton transmission channel, finally improves the catalyst utilization and the electrolysis efficiency through the high-efficiency and stable catalyst / ionomer interface, and reduces the cost of the proton exchange membrane water electrolysis anode catalyst.

Description

Technical Field

[0001] This invention relates to the field of proton exchange membrane electrolysis technology, and in particular to a dual-site supported noble metal catalyst, its preparation method, and its application. Background Technology

[0002] Proton exchange membrane electrolysis (PEMWE) has become a key technology for green hydrogen production due to its high energy conversion efficiency, fast response speed, high-purity hydrogen production, and clean and pollution-free operation. It is widely used in energy storage, transportation, and industrial production. The membrane electrode assembly (MEA) is one of the core components of PEM water electrolysis hydrogen production technology, typically composed of a proton exchange membrane (PEM), a catalyst layer (CL), and a porous transport layer (PTL).

[0003] The catalyst layer is the core site of electrochemical reactions involving multiphase mass transport and energy conversion, and is crucial for PEM (Polymerase Electrolysis) in water electrolysis to produce hydrogen. The electrochemical performance and stability of the catalyst layer primarily depend on the constructed electrode interface structure, namely the catalyst / ionomer interface, which requires a balance between proton, electron, and water / gas transport processes. The ionomer not only acts as a binder to bond catalyst particles and form a stable electrode, but also serves as a crucial proton channel as a solid electrolyte. Excessive ionomer adsorption can lead to the covering of catalyst active sites, causing "poisoning," and hindering the effective transport of reaction gaseous products. Insufficient ionomer adsorption, on the other hand, will affect performance due to the lack of proton channels, and insufficient mechanical strength will make it difficult to maintain long-term stable operation under operating conditions. Balancing the ionomer adsorption sites and kinetic reaction active sites on the catalyst surface is key to achieving efficient utilization of PEM water electrolysis catalysts. Existing pursuits of single active sites are no longer sufficient to meet the requirements of the complex interfacial reactions mentioned above; therefore, there is an urgent need to develop and design new catalyst structures that simultaneously meet the operating requirements of dual active sites.

[0004] Existing research on PEM anode catalysts has focused on the development of active sites, and various approaches have been proposed. For example, increasing the number of active sites through morphological optimization; improving activity by adjusting the electronic structure of active sites through atomic doping; increasing the dispersion of noble metals through support loading; and enhancing catalyst activity and stability through metal-support interactions. These strategies all aim to optimize the active sites of the catalyst, but their effectiveness is often limited when applied to practical operating conditions. The main reason for this is the neglect of the effective construction of ionomer adsorption sites, lacking a "switch" for expressing the operating conditions of the active sites.

[0005] CN116925576A discloses a relatively simple method for modifying carbon supports. This method mainly optimizes the morphology of the support by modifying the carbon support with small-molecule organic acids to increase the anchoring efficiency of the noble metal Pt within the pores and reduce ionomer poisoning. However, the above method still cannot avoid the poisoning effect of ionomers on the catalyst. Ionomers inevitably enter the pores, accompanied by severe poisoning of Pt nanoparticles on the outer surface. Furthermore, the preparation of mesoporous carbon supports is relatively cumbersome and involves a large amount of post-treatment wastewater, preventing mass production.

[0006] CN116613326A discloses a method for preparing membrane electrodes by layer-printing different catalyst layers. This method adjusts the electrode preparation process, and the inkjet printing ink for the catalyst layer consists only of solvent and catalyst. By constructing a macroscopic three-phase reaction interface, the poisoning effect of ionomers on the catalyst is avoided. However, the prepared catalyst layer still has a macroscopic interface between ionomers and catalyst, making it impossible to avoid the poisoning effect of ionomers on the Pt catalyst. Furthermore, the inkjet printing operation is complex and not conducive to large-scale preparation.

[0007] CN115786974A discloses a catalyst for water electrolysis and its preparation method. The method obtains a catalyst precursor, which includes a support precursor and a noble metal oxide precursor supported thereon. The support precursor is a non-noble metal inorganic oxide support. In the preparation process, the catalyst precursor is first post-treated to form oxygen vacancies on both the support precursor and the noble metal oxide precursor. The post-treatment step includes annealing under an ammonia atmosphere.

[0008] The above design approach does not fundamentally solve the problem of ionomer adsorption; it only limits ionomer poisoning through physical isolation or process adjustments, lacking molecular-level chemical considerations. Furthermore, the operational procedures are relatively complex, limiting the possibility of scale-up production. Additionally, PEM water electrolysis and fuel cells operate under different conditions, requiring consideration of more complex interfacial reactions and hydrothermal effects.

[0009] In view of this, the present invention is hereby proposed. Summary of the Invention

[0010] The purpose of this invention is to provide a dual-site supported noble metal catalyst, its preparation method, and its application. The dual-site supported noble metal catalyst of this invention utilizes a hydrophilic oxide with hydroxyl-rich surface as a support to support the active noble metal. The hydroxyl sites on the support surface serve as strong adsorption sites for ionomers, promoting the exposure of the active noble metal and improving the performance expression of the active sites.

[0011] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0012] In a first aspect, the present invention provides a dual-site supported noble metal catalyst, the dual-site supported noble metal catalyst comprising a noble metal oxide and a hydrophilic oxide with hydroxyl-rich surface coated in the noble metal oxide.

[0013] Preferably, the noble metal oxide is selected from any one or a combination of at least two of ruthenium oxide, rhodium oxide, iridium oxide, or platinum oxide, with iridium oxide being the most preferred.

[0014] Preferably, the loading of the noble metal oxide is 10 to 70 wt%.

[0015] Preferably, the hydrophilic oxide includes any one or a combination of at least two of titanium oxide, niobium oxide, tin oxide, or silicon oxide.

[0016] Preferably, the particle size of the hydrophilic oxide is 10 nm to 1 μm.

[0017] Preferably, the hydroxyl content in the hydrophilic oxide rich in hydroxyl groups on the surface is 25-75% (the content here refers to the ratio of the hydroxyl signal to the total oxygen signal on the surface after the mass spectrometry peak signal of H2O is measured).

[0018] Preferably, the surface-rich hydrophilic oxide is prepared by the following steps:

[0019] The hydrophilic oxide is immersed in a modification solution, then washed and dried to obtain the hydrophilic oxide with hydroxyl-rich surface; wherein the modification solution includes any one or a combination of at least two of hydrogen peroxide, a strong base, and a catalyst for the Fenton reaction.

[0020] Preferably, the strong alkali includes any one or a combination of at least two of sodium hydroxide, potassium hydroxide, lithium hydroxide, cesium hydroxide, or rubidium hydroxide.

[0021] Preferably, the catalyst for the Fenton reaction comprises any one or a combination of at least two of ferrous chloride, ferrous nitrate, or ferrous sulfate.

[0022] Preferably, the hydrophilic oxide has a mass percentage content of 0.5% to 5% in the modified solution.

[0023] Preferably, the soaking temperature is 70–90°C, and the soaking time is 20–120 min.

[0024] Preferably, the modified solution contains 3-30% hydrogen peroxide by mass.

[0025] Preferably, the modified solution contains 1-25% by mass of strong alkali.

[0026] Preferably, the mass percentage of the catalyst for the Fenton reaction in the modified solution is 5-50%.

[0027] In a second aspect, the present invention provides a method for preparing a dual-site supported noble metal catalyst as described in the first aspect, the method comprising the following steps:

[0028] (1) Hydrophilic oxides with hydroxyl-rich surfaces are ultrasonically dispersed into an alcohol solution, a precursor solution of noble metals is added dropwise, and the mixture is dried after stirring to obtain a solid mixture;

[0029] (2) The molten salt and the solid mixture obtained in step (1) are mixed and ground to obtain the ground product;

[0030] (3) The grinding product obtained in step (2) is calcined to obtain the calcined product; the calcined product is then ultrasonically dispersed in an aqueous solution, centrifuged and washed, and then dried and ground to obtain the dual-site supported noble metal catalyst.

[0031] Preferably, in step (1), the mass ratio of the metal element to the noble metal precursor in the surface-rich hydrophilic oxide is 1:(0.15~3.35).

[0032] Preferably, in step (1), the mass-to-volume ratio of the hydrophilic oxide with hydroxyl-rich surface to the alcohol solution is 1 g:(100-150) mL.

[0033] Preferably, in step (1), the mass-to-volume ratio of the metal precursor to the alcohol solution in the noble metal precursor solution is 1 g:(10-50) mL.

[0034] Preferably, in step (1), the alcohol solution is isopropanol.

[0035] Preferably, in step (1), the precursor of the noble metal includes any one or a combination of at least two of ruthenic acid, rhodium chloroacetate, iridium chloroacetate, ruthenic trichloride, iridium acetate, iridium acetylacetonate, or chloroplatinic acid.

[0036] Preferably, in step (1), the stirring temperature is 40-60°C and the stirring time is 1-3 hours.

[0037] Preferably, in step (1), the drying temperature is 60-90°C and the drying time is 3-5 hours.

[0038] Preferably, in step (2), the mass ratio of the molten salt to the solid mixture is (1.43 to 19.14):1, and more preferably (4.78 to 19.14):1.

[0039] Preferably, in step (2), the grinding speed is 100-300 rpm, the grinding time is 0.5-2 h, and the particle size of the grinding product obtained by grinding is 300-500 nm.

[0040] Preferably, in step (3), the calcination temperature is 250-450℃, the calcination time is 0.5-2h, and the calcination heating rate is 5-15℃ / min.

[0041] Preferably, in step (3), the number of centrifugal washing cycles is 3 to 6.

[0042] Preferably, in step (3), the drying temperature is 60-80°C and the drying time is 4-6 hours.

[0043] Preferably, in step (3), the grinding speed is 100-300 rpm and the grinding time is 0.5-2 h.

[0044] Preferably, in step (3), the particle size of the dual-site supported noble metal catalyst is 10 nm to 1 μm.

[0045] Thirdly, the present invention provides the application of the dual-site supported noble metal catalyst as described in the first aspect in the preparation of an anode catalyst for PEM water electrolysis, a membrane electrode for PEM water electrolysis, or an electrolytic cell for PEM water electrolysis.

[0046] Fourthly, the present invention provides a membrane electrode for PEM water electrolysis, the membrane electrode for PEM water electrolysis comprising a proton exchange membrane and an anode catalyst layer and a cathode catalyst layer disposed on both sides of the proton exchange membrane; wherein the anode catalyst layer comprises a dual-site supported noble metal catalyst as described in the first aspect.

[0047] Preferably, the loading of noble metal elements in the anode catalyst layer is 0.100–1.000 mg / cm³. 2 .

[0048] Preferably, the anode catalyst layer further includes ionomers.

[0049] Preferably, the ionomer comprises any one or a combination of at least two of perfluorosulfonic acid, sulfonated polyether ether ketone resin or sulfonated trifluorostyrene resin, preferably perfluorosulfonic acid.

[0050] Preferably, the loading of noble metal elements in the cathode catalyst layer is 0.100–1.000 mg / cm³. 2 .

[0051] Preferably, the proton exchange membrane is a 115 proton exchange membrane.

[0052] Fifthly, the present invention provides a method for preparing a membrane electrode for PEM water electrolysis according to the fourth aspect, the method comprising the following steps:

[0053] A dual-site supported noble metal catalyst, an ionomer solution, water, and alcohol were mixed, stirred and dispersed, and then degassed after ball milling to obtain an anode catalyst slurry.

[0054] The anode catalyst layer slurry is coated onto one side of the transfer substrate and dried to form the anode catalyst layer.

[0055] The cathode catalyst layer slurry is coated onto the other side of the transfer substrate and dried to form the cathode catalyst layer.

[0056] The anode catalyst layer and the cathode catalyst layer are transferred to both sides of the proton exchange membrane by hot pressing to obtain the membrane electrode for PEM water electrolysis.

[0057] Preferably, the dual-site supported noble metal catalyst accounts for 15-40% of the total mass of the anode catalyst layer slurry.

[0058] Preferably, the ionomer solution comprises 5 to 40% of the mass of the dual-site supported noble metal catalyst.

[0059] Preferably, the solid content of the ionomer solution is 15-20 wt%.

[0060] Preferably, the alcohol is a monohydric liquid alcohol of C1 to C8 and / or a polyhydric liquid alcohol of C1 to C8.

[0061] Preferably, the alcohol is selected from any one or a combination of at least two of ethanol, n-propanol, isopropanol, or propylene glycol.

[0062] Preferably, the mass ratio of water to alcohol is (5-8):(2-5).

[0063] Preferably, the ball milling conditions include: ZrO2 milling beads of 2.0–4.5 mm, constant temperature ball milling at 15–25°C, rotation speed of 300–1000 rpm, and time of 2–12 h.

[0064] In a sixth aspect, the present invention provides an electrolytic cell for PEM water electrolysis, the electrolytic cell for PEM water electrolysis comprising the membrane electrode for PEM water electrolysis described in the fourth aspect.

[0065] Compared with the prior art, the present invention has the following beneficial effects:

[0066] (1) When the dual-site supported noble metal catalyst of this invention is applied to a device, the charge transfer impedance is reduced by 30%, demonstrating its improved performance. Simultaneously, a high current density (6.0 A / cm²) is achieved. 2 Under the operating conditions, the performance improved by 266 mV, demonstrating the high performance of the two-site catalyst in PEM applications.

[0067] (2) From the perspective of actual operating conditions, the reaction sites of the catalyst under operating conditions are analyzed, providing a new perspective for the structural design of next-generation catalysts. The dual-site supported noble metal catalyst of this invention successfully achieves the reactivation of the "poisoned" catalyst by introducing structural sites, thereby improving the catalyst utilization rate and providing a feasible solution for large-scale, low-cost hydrogen production. Attached Figure Description

[0068] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0069] Figure 1 XPS test images of the hydrophilic oxide provided in Example 1 before and after hydroxylation treatment.

[0070] Figure 2 Temperature-programmed desorption test diagrams of the dual-site supported noble metal catalyst provided in Example 1 and the catalyst provided in Comparative Example 3.

[0071] Figure 3 Transmission electron microscopy (TEM) image of the dual-site supported noble metal catalyst provided in Example 3.

[0072] Figure 4 Transmission electron microscopy (TEM) image of the catalyst provided for Comparative Example 3.

[0073] Figure 5 PEM water electrolysis performance curves of membrane electrodes prepared using the dual-site supported noble metal catalyst provided in Example 6 and the catalyst provided in Comparative Example 6.

[0074] Figure 6 In-situ impedance spectra of membrane electrodes prepared using the dual-site supported noble metal catalyst provided in Example 6 and the catalyst provided in Comparative Example 6. Detailed Implementation

[0075] Unless otherwise defined herein, scientific and process terms used in conjunction with this invention should have the meanings commonly understood by one of ordinary skill in the art. The meaning and scope of terms should be clear; however, in any case of potential ambiguity, the definitions provided herein take precedence over any dictionary or foreign definitions. In this application, unless otherwise stated, the use of "or" means "and / or". Furthermore, the use of the term "comprising" and other forms is non-limiting.

[0076] It should be noted that specific details are set forth in the following description to provide a full understanding of the invention. However, the invention can be practiced in many ways other than those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0077] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0078] In a first aspect, the present invention provides a dual-site supported noble metal catalyst, the dual-site supported noble metal catalyst comprising a noble metal oxide and a hydrophilic oxide with hydroxyl-rich surface coated in the noble metal oxide.

[0079] In this invention, the catalyst structure is readjusted and designed from the perspective of actual working conditions to construct a dual-site supported noble metal catalyst. This catalyst is an anode catalyst structure with dual-site synergistic reaction. It uses hydrophilic oxides with hydroxyl-rich surfaces as supports to support active noble metals, and uses the hydroxyl sites on the support surface as strong adsorption sites for ionomers to promote the exposure of active noble metals and improve the performance expression of active sites.

[0080] In this invention, the adsorption sites of the ionomer in the dual-site supported noble metal catalyst are separated from the active sites, increasing the exposure of the active sites while constructing a stable proton transport channel. Ultimately, this results in improved catalyst utilization and electrolysis efficiency through a highly efficient and stable catalyst / ionomer interface, reducing the cost of the PEM water electrolysis anode catalyst. This invention provides a low-cost, easy-to-operate structure and preparation method for a PEM water electrolysis anode catalyst.

[0081] As an optional implementation, the noble metal oxide is selected from any one or a combination of at least two of ruthenium oxide, rhodium oxide, iridium oxide, or platinum oxide, preferably iridium oxide.

[0082] As an optional implementation, the loading of the noble metal oxide is 10 to 70 wt%, for example, it can be 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, etc.

[0083] In this invention, the noble metal loading can be further adjusted to expose the hydroxyl-rich support, which serves as a strong adsorption site for the ionomer, thereby inhibiting the surface adsorption of the noble metal oxide.

[0084] As an optional implementation, the hydrophilic oxide includes any one or a combination of at least two of titanium oxide, niobium oxide, tin oxide, or silicon oxide.

[0085] As an optional implementation, the particle size of the hydrophilic oxide is 10nm to 1μm, for example, it can be 10nm, 20nm, 40nm, 60nm, 80nm, 100nm, 120nm, 140nm, 160nm, 180nm, 200nm, 250nm, 300nm, 350nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1μm, etc.

[0086] As an optional implementation, the hydroxyl content in the surface-rich hydrophilic oxide is 25% to 75%, for example, it can be 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, etc.

[0087] It should be noted that the content here refers to the ratio of hydroxyl signal to total surface oxygen signal after H2O mass spectrometry peak signal testing.

[0088] As an optional implementation, the surface-rich hydrophilic oxide is prepared by the following steps:

[0089] The hydrophilic oxide is immersed in a modification solution, then washed and dried to obtain the hydrophilic oxide with hydroxyl-rich surface; wherein the modification solution includes any one or a combination of at least two of hydrogen peroxide, a strong base, and a catalyst for the Fenton reaction.

[0090] In this invention, hydroxyl groups are modified on the surface of the hydrophilic oxide by the specific modification method described above, so that the surface of the dual-site catalyst has more surface hydroxyl groups, which is beneficial for the adsorption of ionomers, thereby constructing a stable proton transport channel.

[0091] As an optional implementation, the strong base includes any one or a combination of at least two of sodium hydroxide, potassium hydroxide, lithium hydroxide, cesium hydroxide, or rubidium hydroxide.

[0092] As an optional implementation, the catalyst for the Fenton reaction includes any one or a combination of at least two of ferrous chloride, ferrous nitrate, or ferrous sulfate.

[0093] As an optional implementation, the hydrophilic oxide has a mass percentage content of 0.5% to 5% in the modified solution, for example, it can be 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc.

[0094] As an optional implementation, the soaking temperature is 70-90℃, for example, it can be 70℃, 72℃, 74℃, 75℃, 76℃, 78℃, 80℃, 82℃, 84℃, 85℃, 86℃, 88℃, 90℃, etc., and the soaking time is 20-120min, for example, it can be 20min, 25min, 30min, 35min, 40min, 45min, 50min, 55min, 60min, 65min, 70min, 75min, 80min, 85min, 90min, 95min, 100min, 105min, 110min, 115min, 120min.

[0095] As an optional implementation, the mass percentage of hydrogen peroxide in the modified solution is 3% to 30%, for example, it can be 3%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, etc.

[0096] As an optional implementation, the mass percentage of strong alkali in the modified solution is 1% to 25%, for example, it can be 1%, 2%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 25%, etc.

[0097] As an optional implementation, the mass percentage of the catalyst for the Fenton reaction in the modified solution is 5% to 50%, for example, it can be 5%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, 40%, 42%, 44%, 46%, 48%, 50%, etc.

[0098] In a second aspect, the present invention provides a method for preparing a dual-site supported noble metal catalyst as described in the first aspect, the method comprising the following steps:

[0099] (1) Hydrophilic oxides with hydroxyl-rich surfaces are ultrasonically dispersed into an alcohol solution, a precursor solution of noble metals is added dropwise, and the mixture is dried after stirring to obtain a solid mixture;

[0100] (2) The molten salt and the solid mixture obtained in step (1) are mixed and ground to obtain the ground product;

[0101] (3) The grinding product obtained in step (2) is calcined to obtain the calcined product; the calcined product is then ultrasonically dispersed in an aqueous solution, centrifuged and washed, and then dried and ground to obtain the dual-site supported noble metal catalyst.

[0102] As an optional implementation, in step (1), the mass ratio of the metal element to the noble metal precursor in the hydrophilic oxide with hydroxyl-rich surface is 1:(0.15~3.35), for example, it can be 1:0.15, 1:0.5, 1:0.65, 1:1, 1:1.15, 1:1.5, 1:1.65, 1:2, 1:2.15, 1:2.5, 1:2.65, 1:3, 1:3.15, 1:3.35, etc.

[0103] As an optional implementation, in step (1), the mass-to-volume ratio of the hydrophilic oxide with hydroxyl-rich surface to the alcohol solution is 1g:(100-150)mL, for example, it can be 1g:100mL, 1g:110mL, 1g:120mL, 1g:130mL, 1g:140mL, 1g:150mL, etc.

[0104] As an optional implementation, in step (1), the mass-to-volume ratio of the metal precursor to the alcohol solution in the noble metal precursor solution is 1g:(10-50)mL, for example, it can be 1g:10mL, 1g:15mL, 1g:20mL, 1g:25mL, 1g:30mL, 1g:35mL, 1g:40mL, 1g:45mL, 1g:50mL, etc.

[0105] As an optional implementation, in step (1), the alcohol solution is isopropanol.

[0106] As an optional implementation, in step (1), the precursor of the noble metal includes any one or a combination of at least two of chlororuthenic acid, chlororhodium acid, chloroiridium acid, or chloroplatinic acid.

[0107] As an optional implementation, in step (1), the stirring temperature is 40-60℃, for example, it can be 40℃, 42℃, 44℃, 45℃, 46℃, 48℃, 50℃, 52℃, 54℃, 55℃, 56℃, 58℃, 60℃, etc., and the stirring time is 1-3h, for example, it can be 1h, 1.2h, 1.5h, 1.6h, 1.8h, 2h, 2.2h, 2.4h, 2.5h, 2.6h, 2.8h, 3h, etc.

[0108] As an optional implementation, in step (1), the drying temperature is 60-90℃, for example, it can be 60℃, 62℃, 64℃, 65℃, 66℃, 68℃, 70℃, 72℃, 74℃, 75℃, 76℃, 78℃, 80℃, 82℃, 84℃, 85℃, 86℃, 88℃, 90℃, etc., and the drying time is 3-5h, for example, it can be 3h, 3.2h, 3.5h, 3.6h, 3.8h, 4h, 4.2h, 4.4h, 4.5h, 4.6h, 4.8h, 5h, etc.

[0109] As an optional implementation, in step (2), the mass ratio of the molten salt to the solid mixture is (1.43 to 19.14):1, for example, it can be 1.43:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, 19.14:1, etc., preferably (4.78 to 19.14):1.

[0110] As an optional implementation, in step (2), the grinding speed is 100 to 300 rpm, for example, 100 rpm, 150 rpm, 200 rpm, 250 rpm, 300 rpm, etc., and the grinding time is 0.5 to 2 hours, for example, 0.5 hours, 0.6 hours, 0.8 hours, 1 hour, 1.2 hours, 1.4 hours, 1.5 hours, 1.6 hours, 1.8 hours, 2 hours, etc.

[0111] As an optional implementation, in step (2), the particle size of the grinding product obtained by grinding is 300-500nm, for example, it can be 300nm, 320nm, 340nm, 350nm, 360nm, 380nm, 400nm, 420nm, 440nm, 450nm, 460nm, 480nm, 500nm, etc.

[0112] As an optional implementation, in step (3), the calcination temperature is 250-450℃, for example, it can be 250℃, 260℃, 280℃, 300℃, 320℃, 340℃, 350℃, 360℃, 380℃, 400℃, 420℃, 440℃, 450℃, etc., the calcination time is 0.5-2h, for example, it can be 0.5h, 0.6h, 0.8h, 1h, 1.2h, 1.4h, 1.6h, 1.8h, 2h, etc., the calcination heating rate is 5-15℃ / min, for example, it can be 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, 10℃ / min, 11℃ / min, 12℃ / min, 13℃ / min, 14℃ / min, 15℃ / min, etc.

[0113] As an optional implementation, in step (3), the number of centrifugal washing cycles is 3 to 6 times, for example, 3 times, 4 times, 5 times, 6 times, etc.

[0114] As an optional implementation, in step (3), the drying temperature is 60-80℃, for example, it can be 60℃, 62℃, 64℃, 65℃, 66℃, 68℃, 70℃, 72℃, 74℃, 75℃, 76℃, 78℃, 80℃, etc., and the drying time is 4-6h, for example, it can be 4h, 4.2h, 4.4h, 4.6h, 4.8h, 5h, 5.2h, 5.4h, 5.6h, 5.8h, 6h, etc.

[0115] As an optional implementation, in step (3), the grinding speed is 100 to 300 rpm, for example, it can be 100 rpm, 120 rpm, 140 rpm, 150 rpm, 160 rpm, 180 rpm, 200 rpm, 220 rpm, 240 rpm, 250 rpm, 260 rpm, 280 rpm, 300 rpm, etc., and the grinding time is 0.5 to 2 hours, for example, it can be 0.5 hours, 0.6 hours, 0.8 hours, 1 hour, 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours, 2 hours, etc.

[0116] As an optional implementation, in step (3), the particle size of the dual-site supported noble metal catalyst is 10nm to 1μm, for example, it can be 10nm, 20nm, 40nm, 60nm, 80nm, 100nm, 120nm, 140nm, 160nm, 180nm, 200nm, 250nm, 300nm, 350nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1μm, etc.

[0117] Thirdly, the present invention provides the application of the dual-site supported noble metal catalyst as described in the first aspect in the preparation of an anode catalyst for PEM water electrolysis, a membrane electrode for PEM water electrolysis, or an electrolytic cell for PEM water electrolysis.

[0118] Fourthly, the present invention provides a membrane electrode for PEM water electrolysis, the membrane electrode for PEM water electrolysis comprising a proton exchange membrane and an anode catalyst layer and a cathode catalyst layer disposed on both sides of the proton exchange membrane; wherein the anode catalyst layer comprises a dual-site supported noble metal catalyst as described in the first aspect.

[0119] As an optional embodiment, the loading of noble metal elements in the anode catalyst layer is 0.100–1.000 mg / cm³. 2 For example, it could be 0.100 mg / cm³ 2 0.200 mg / cm 2 0.300 mg / cm 2 0.400 mg / cm 2 0.500 mg / cm 2 0.600 mg / cm 2 0.700 mg / cm 2 0.800 mg / cm 2 0.900 mg / cm 2 1.000 mg / cm 2 wait.

[0120] As an optional implementation, the anode catalyst layer further includes an ionomer.

[0121] As an optional implementation, the ionomer includes any one or a combination of at least two of perfluorosulfonic acid, sulfonated polyether ether ketone resin or sulfonated trifluorostyrene resin, preferably perfluorosulfonic acid.

[0122] As an optional embodiment, the loading of noble metal elements in the cathode catalyst layer is 0.100–1.000 mg / cm³. 2 For example, it could be 0.100 mg / cm³ 2 0.200 mg / cm 2 0.300 mg / cm 2 0.400 mg / cm 2 0.500 mg / cm 2 0.600 mg / cm 2 0.700 mg / cm 2 0.800 mg / cm 2 0.900 mg / cm 2 1.000 mg / cm 2wait.

[0123] As an optional implementation, the proton exchange membrane is a 115 proton exchange membrane.

[0124] Fifthly, the present invention provides a method for preparing a membrane electrode for PEM water electrolysis according to the fourth aspect, the method comprising the following steps:

[0125] A dual-site supported noble metal catalyst, an ionomer solution, water, and alcohol were mixed, stirred and dispersed, and then degassed after ball milling to obtain an anode catalyst slurry.

[0126] The anode catalyst layer slurry is coated onto one side of the transfer substrate and dried to form the anode catalyst layer.

[0127] The cathode catalyst layer slurry is coated onto the other side of the transfer substrate and dried to form the cathode catalyst layer.

[0128] The anode catalyst layer and the cathode catalyst layer are transferred to both sides of the proton exchange membrane by hot pressing to obtain the membrane electrode for PEM water electrolysis.

[0129] As an optional implementation, the dual-site supported noble metal catalyst accounts for 15% to 40% of the total mass of the anode catalyst layer slurry, for example, it can be 15%, 16%, 18%, 20%, 22%, 24%, 25%, 26%, 28%, 30%, 32%, 34%, 35%, 36%, 38%, 40%, etc.

[0130] As an optional embodiment, the ionomer solution is 5% to 40% of the mass of the dual-site supported noble metal catalyst, for example, it can be 5%, 6%, 8%, 10%, 12%, 15%, 16%, 18%, 20%, 22%, 24%, 25%, 26%, 28%, 30%, 32%, 34%, 35%, 36%, 38%, 40%, etc.

[0131] As an optional implementation, the solid content of the ionomer solution is 15-20 wt%, for example, it can be 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt%, etc.

[0132] As an optional implementation, the alcohol is a monohydric liquid alcohol of C1 to C8 and / or a polyhydric liquid alcohol of C1 to C8.

[0133] As an optional implementation, the alcohol is selected from any one or a combination of at least two of ethanol, n-propanol, isopropanol, or propylene glycol.

[0134] As an optional implementation, the mass ratio of water to alcohol is (5-8):(2-5), for example, it can be 5:5, 6:4, 7:3, 8:2, etc.

[0135] As an optional implementation, the ball milling conditions include: using ZrO2 milling beads of 2.0 to 4.5 mm, constant temperature ball milling at 15 to 25°C, rotating at 300 to 1000 rpm, and for 2 to 12 hours.

[0136] As an optional implementation, the ZrO2 grinding beads have a particle size of 2.0 to 4.5 mm, for example, 2.0 mm, 2.2 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.8 mm, 3 mm, 3.2 mm, 3.4 mm, 3.5 mm, 3.6 mm, 3.8 mm, 4 mm, 4.2 mm, 4.4 mm, 4.5 mm, etc.

[0137] As an optional implementation, the ball milling temperature is 15-25°C, for example, it can be 15°C, 16°C, 17°C, 18°C, 19°C, 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, etc.

[0138] As an optional implementation, the rotational speed of the ball mill is 300 to 1000 rpm, for example, it can be 300 rpm, 350 rpm, 400 rpm, 450 rpm, 500 rpm, 550 rpm, 600 rpm, 650 rpm, 700 rpm, 750 rpm, 800 rpm, 850 rpm, 900 rpm, 950 rpm, 1000 rpm, etc.

[0139] As an optional implementation, the ball milling time is 2 to 12 hours, for example, it can be 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 7.5 hours, 8 hours, 8.5 hours, 9 hours, 9.5 hours, 10 hours, 10.5 hours, 11 hours, 11.5 hours, 12 hours, etc.

[0140] In a sixth aspect, the present invention provides an electrolytic cell for PEM water electrolysis, the electrolytic cell for PEM water electrolysis comprising the membrane electrode for PEM water electrolysis described in the fourth aspect.

[0141] The present invention will be further illustrated below by way of examples. Unless otherwise specified, the materials in the examples are prepared according to existing methods or purchased directly from the market.

[0142] Preparation Example 1

[0143] This preparation example provides a niobium oxide with a surface rich in hydroxyl groups, which is prepared by the following steps:

[0144] 1.0 g of niobium oxide was soaked in hydrogen peroxide (100 mL, 30 wt% H2O2) at 80 °C for 30 min, then washed several times with deionized water, and then dried in an oven at 80 °C to obtain niobium oxide with hydroxyl-rich surface (hydroxyl content of 53.2%).

[0145] Preparation Example 2

[0146] This preparation example provides a tin oxide with a surface rich in hydroxyl groups, which is prepared by the following steps:

[0147] 1.0 g of tin oxide was soaked in hydrogen peroxide (80 mL, 20 wt% H2O2) at 80 °C for 1 h, then washed several times with deionized water, and then dried in an oven at 80 °C to obtain tin oxide with hydroxyl-rich surface (hydroxyl content of 42.7%).

[0148] Preparation Example 3

[0149] This preparation example provides a silica with a surface rich in hydroxyl groups, which is prepared by the following steps:

[0150] 1.0 g of silica was soaked in hydrogen peroxide (50 mL, 10 wt% H2O2) at 80 °C for 1.5 h, then washed several times with deionized water, and then dried in an oven at 80 °C to obtain silica with hydroxyl-rich surface (hydroxyl content of 48.6%).

[0151] Preparation Example 4

[0152] This preparation example provides a titanium dioxide with a surface rich in hydroxyl groups, which is prepared by the following steps:

[0153] 1.0 g of titanium dioxide was soaked in hydrogen peroxide (100 mL, 30 wt% H2O2) at 80 °C for 2 h, then washed several times with deionized water, and then dried in an 80 °C oven to obtain titanium dioxide with hydroxyl-rich surface (hydroxyl content of 72.4%).

[0154] Preparation Example 5

[0155] This preparation example provides a niobium oxide with a surface rich in hydroxyl groups. The only difference from Preparation Example 1 is that 20 wt% NaOH is added to the hydrogen peroxide. The other steps are completely consistent with Preparation Example 1.

[0156] Preparation Example 6

[0157] This preparation example provides a niobium oxide with a surface rich in hydroxyl groups. The only difference from Preparation Example 1 is that 10 wt% FeCl2 is added to the hydrogen peroxide. The other steps are completely consistent with Preparation Example 1.

[0158] Test Example 1

[0159] XPS Test

[0160] Test samples: Hydrophilic oxides with hydroxyl-rich surfaces provided in Preparation Examples 1 to 6, and the corresponding hydrophilic oxides before hydroxylation treatment in each example.

[0161] Test method: XPS test, observe and count the proportion of hydroxyl peaks.

[0162] The test results are shown in Table 1 below. Figure 1 As shown:

[0163] Table 1

[0164]

[0165] From Table 1 and Figure 1 As shown, after hydroxylation treatment, the proportion of surface hydroxyl functional groups (second peak) of hydrophilic oxides is significantly increased.

[0166] Example 1

[0167] This embodiment provides a two-site supported noble metal catalyst, which is prepared by the following steps:

[0168] (1) 1g of niobium oxide with hydroxyl-rich surface (average particle size of 10nm) provided in Preparation Example 1 was ultrasonically dispersed into 100mL of isopropanol solution, and then 100mL of H2IrCl6 solution (concentration of 0.015g / mL) was added dropwise. After stirring for 1h to form a uniformly dispersed solution, the solution was dried in an oven at 60℃ for 5h to form a solid mixture.

[0169] (2) Grind the solid mixture with NaNO3 at a mass ratio of 4.75:1 until homogeneous (100 rpm, 2 h) to obtain the grinding product (average particle size of 100 nm).

[0170] (3) The ground product was calcined at 250℃ for 2 hours, with a heating rate preferably of 5℃ / min; it was naturally cooled to room temperature, ultrasonically dispersed in an aqueous solution, centrifuged and washed 6 times to remove excess impurity salts, dried in a 70℃ oven for 6 hours, and ground evenly (100 rpm, 2 hours) to obtain a dual-site supported noble metal catalyst (average particle size of 12 nm).

[0171] Example 2

[0172] This embodiment provides a two-site supported noble metal catalyst, which is prepared by the following steps:

[0173] (1) 1g of niobium oxide with hydroxyl-rich surface (average particle size of 50nm) provided in Preparation Example 1 was ultrasonically dispersed into 125mL of isopropanol solution, and then 60mL of H2IrCl6 solution (concentration of 0.062g / mL) was added dropwise. After stirring for 2h to form a uniformly dispersed solution, the solution was dried in an oven at 75℃ for 4h to form a solid mixture.

[0174] (2) Grind the solid mixture with NaNO3 in a mass ratio of 10:1 until homogeneous (200 rpm, 1 h) to obtain the grinding product (average particle size of 100 nm).

[0175] (3) The ground product was calcined at 350℃ for 1h, with a preferred heating rate of 10℃ / min; it was naturally cooled to room temperature, ultrasonically dispersed in an aqueous solution, centrifuged and washed 4 times to remove excess impurity salts, dried in an 80℃ oven for 4h, and ground evenly (200rpm, 1h) to obtain a dual-site supported noble metal catalyst (average particle size of 55nm).

[0176] Example 3

[0177] This embodiment provides a two-site supported noble metal catalyst, which is prepared by the following steps:

[0178] (1) 1g of niobium oxide with hydroxyl-rich surface (average particle size of 100nm) provided in Preparation Example 1 was ultrasonically dispersed into 150mL of isopropanol solution, and then 50mL of H2IrCl6 solution (concentration of 0.049g / mL) was added dropwise. After stirring for 2h to form a uniformly dispersed solution, the solution was dried in an oven at 90℃ for 3h to form a solid mixture.

[0179] (2) Grind the solid mixture with NaNO3 at a mass ratio of 19.14:1 until homogeneous (300 rpm, 0.5 h) to obtain the grinding product (average particle size of 300 nm).

[0180] (3) The ground product was calcined at 450℃ for 0.5h, with a preferred heating rate of 15℃ / min; it was naturally cooled to room temperature, ultrasonically dispersed in an aqueous solution, centrifuged and washed 3 times to remove excess impurity salts, dried in a 60℃ oven for 6h, and ground evenly (300rpm, grinding for 0.5h) to obtain a dual-site supported noble metal catalyst (average particle size of 104nm).

[0181] Example 4

[0182] This embodiment provides a dual-site supported noble metal catalyst, which differs from Example 1 only in that the niobium oxide with hydroxyl-rich surface provided in Preparation Example 1 is replaced with an equal amount of tin oxide with hydroxyl-rich surface provided in Preparation Example 2. The other steps are completely consistent with Example 1.

[0183] Example 5

[0184] This embodiment provides a dual-site supported noble metal catalyst, which differs from Example 1 only in that the niobium oxide with hydroxyl-rich surface provided in Preparation Example 1 is replaced with an equal amount of silica with hydroxyl-rich surface provided in Preparation Example 3. The other steps are completely consistent with Example 1.

[0185] Example 6

[0186] This embodiment provides a dual-site supported noble metal catalyst, which differs from Example 1 only in that the niobium oxide with hydroxyl-rich surface provided in Preparation Example 1 is replaced with an equal amount of titanium dioxide with hydroxyl-rich surface provided in Preparation Example 4. The other steps are completely consistent with Example 1.

[0187] Example 7

[0188] This embodiment provides a dual-site supported noble metal catalyst, which differs from Example 1 only in that the niobium oxide with hydroxyl-rich surface provided in Preparation Example 1 is replaced with an equal amount of niobium oxide with hydroxyl-rich surface provided in Preparation Example 5. The other steps are completely consistent with Example 1.

[0189] Example 8

[0190] This embodiment provides a dual-site supported noble metal catalyst, which differs from Example 1 only in that the niobium oxide with hydroxyl-rich surface provided in Preparation Example 1 is replaced with an equal amount of niobium oxide with hydroxyl-rich surface provided in Preparation Example 6. The other steps are completely consistent with Example 1.

[0191] Example 9

[0192] This embodiment provides a dual-site supported noble metal catalyst, which differs from Example 1 only in that the H2IrCl6 solution is replaced with an equal amount of RuCl3 solution, while the other steps are completely consistent with Example 1.

[0193] Comparative Example 1

[0194] This comparative example provides a catalyst, wherein the catalyst is iridium oxide.

[0195] Comparative Example 2

[0196] This comparative example provides a catalyst, wherein the catalyst is ruthenium oxide.

[0197] Comparative Example 3

[0198] This comparative example provides a catalyst that differs from Example 1 only in that the niobium oxide with hydroxyl-rich surface provided in Preparation Example 1 is replaced with commercially available niobium oxide that has not undergone hydroxylation treatment; all other steps are exactly the same as in Example 1.

[0199] Comparative Example 4

[0200] This comparative example provides a catalyst that differs from Example 4 only in that the hydroxyl-rich tin oxide provided in Preparation Example 2 is replaced with commercially available tin oxide that has not undergone hydroxylation treatment; all other steps are exactly the same as in Example 4.

[0201] Comparative Example 5

[0202] This comparative example provides a catalyst that differs from Example 5 only in that the surface-rich hydroxyl silica provided in Preparation Example 3 is replaced with commercially available silica that has not undergone hydroxylation treatment; all other steps are exactly the same as in Example 5.

[0203] Comparative Example 6

[0204] This comparative example provides a catalyst that differs from Example 6 only in that the surface-rich titanium dioxide provided in Preparation Example 4 is replaced with commercially available titanium dioxide that has not undergone hydroxylation treatment; all other steps are exactly the same as in Example 6.

[0205] Test Example 2

[0206] Programmed temperature desorption test

[0207] Test samples: dual-site supported noble metal catalysts provided in Examples 1-9 and catalysts provided in Comparative Examples 1-6.

[0208] Test method: temperature-propelled desorption test, and statistical analysis of the mass spectrum peak area of ​​H2O.

[0209] The test results are shown in Table 2 below. Figure 2 As shown:

[0210] Table 2

[0211]

[0212]

[0213] From Table 2 and Figure 2 As shown, the peak elution temperature of the dual-site supported noble metal catalyst H2O described in this invention is 341–364 °C, and the mass spectrum peak signal area of ​​H2O is 3.9E-8–6.2E-8. This fully demonstrates that the dual-site catalyst described in this invention has more surface hydroxyl groups, which is beneficial for the adsorption of ionomers and the construction of stable proton transport channels.

[0214] also, Figure 3 Transmission electron microscopy (TEM) image of the dual-site supported noble metal catalyst provided in Example 3. Figure 4 Transmission electron microscopy (TEM) image of the catalyst provided in Comparative Example 3. Figure 3 and Figure 4 As shown in the comparison, traditional catalysts with iridium oxide particles have a large amount of ionomer adsorption on their surface, with a thickness of about 5-10 nm, which causes serious poisoning to the catalyst performance. The dual-site catalyst has basically exposed active sites, achieving a higher active area.

[0215] Application Example 1

[0216] This application example provides a membrane electrode for PEM water electrolysis, which is prepared by the following steps:

[0217] (a) Add deionized water, PEM water electrolysis anolyte catalyst, ionomer solution and alcohol to a glass bottle in sequence. Place the glass bottle on a magnetic stirrer and stir to disperse. Then transfer the solution to a ball milling jar containing grinding balls and ball milling under constant temperature conditions.

[0218] The anode catalyst is the dual-site supported noble metal catalyst provided in Example 1, and the catalyst mass accounts for 25 wt% of the total slurry mass; the ionomer solution is a perfluorosulfonic acid solution, and the ionomer solution mass is 20 wt% of the catalyst mass; the alcohol is isopropanol, and the mass ratio of added deionized water to total liquid alcohol is 6:4.

[0219] The ball milling conditions were as follows: 3.5 mm ZrO2 balls were milled at a constant temperature of 20°C, with a rotation speed of 650 rpm and a time of 7 hours.

[0220] (b) After ball milling and dispersion, the slurry is mixed and degassed using a degassing machine to obtain the anode catalyst layer slurry.

[0221] (c) Coating the PTFE membrane using a slot coater (loading 0.500 mg Ir / cm²). 2 ).

[0222] (d) After drying, the average iridium loading in the catalyst coating was tested by XRF to see if it met the standard.

[0223] (e) Subsequently, a coating with a loading of 0.3 mg Pt / cm was applied to a PTFE membrane. 2 The cathode catalyst layer and the 115 proton exchange membrane are prepared into a catalyst coating membrane (CCM) by hot pressing transfer.

[0224] Application Example 2

[0225] This application example provides a membrane electrode for PEM water electrolysis. The only difference from application example 1 is that the dual-site supported noble metal catalyst provided in example 1 is replaced with the dual-site supported noble metal catalyst provided in example 2 with an equal loading. The other steps are completely the same as in application example 1.

[0226] Application Example 3

[0227] This application example provides a membrane electrode for PEM water electrolysis. The only difference from application example 1 is that the dual-site supported noble metal catalyst provided in example 1 is replaced with the dual-site supported noble metal catalyst provided in example 3 with an equal loading. The other steps are completely consistent with application example 1.

[0228] Application Example 4

[0229] This application example provides a membrane electrode for PEM water electrolysis. The only difference from application example 1 is that the dual-site supported noble metal catalyst provided in example 1 is replaced with the dual-site supported noble metal catalyst provided in example 4 with an equal loading. The other steps are completely the same as in application example 1.

[0230] Application Example 5

[0231] This application example provides a membrane electrode for PEM water electrolysis. The only difference from application example 1 is that the dual-site supported noble metal catalyst provided in example 1 is replaced with the dual-site supported noble metal catalyst provided in example 5 with an equal loading. The other steps are completely the same as in application example 1.

[0232] Application Example 6

[0233] This application example provides a membrane electrode for PEM water electrolysis. The only difference from application example 1 is that the dual-site supported noble metal catalyst provided in example 1 is replaced with the dual-site supported noble metal catalyst provided in example 6 with an equal loading. The other steps are completely the same as in application example 1.

[0234] Application Example 7

[0235] This application example provides a membrane electrode for PEM water electrolysis. The only difference from application example 1 is that the dual-site supported noble metal catalyst provided in example 1 is replaced with the dual-site supported noble metal catalyst provided in example 7 with an equal loading. The other steps are completely the same as in application example 1.

[0236] Application Example 8

[0237] This application example provides a membrane electrode for PEM water electrolysis. The only difference from application example 1 is that the dual-site supported noble metal catalyst provided in example 1 is replaced with the dual-site supported noble metal catalyst provided in example 8 with an equal loading. The other steps are completely the same as in application example 1.

[0238] Application Example 9

[0239] This application example provides a membrane electrode for PEM water electrolysis. The only difference from application example 1 is that the dual-site supported noble metal catalyst provided in example 1 is replaced with the dual-site supported noble metal catalyst provided in example 9 with an equal loading. The other steps are completely the same as in application example 1.

[0240] Comparative Application Example 1

[0241] This application example provides a membrane electrode for PEM water electrolysis. The only difference from application example 1 is that the dual-site supported noble metal catalyst provided in example 1 is replaced with the catalyst provided in comparative example 1 with an equal loading. All other steps are exactly the same as in application example 1.

[0242] Comparative Application Example 2

[0243] This application example provides a membrane electrode for PEM water electrolysis. The only difference from application example 1 is that the dual-site supported noble metal catalyst provided in example 1 is replaced with the catalyst provided in comparative example 2 with an equal loading. The other steps are completely consistent with application example 1.

[0244] Comparative Application Example 3

[0245] This application example provides a membrane electrode for PEM water electrolysis. The only difference from application example 1 is that the dual-site supported noble metal catalyst provided in example 1 is replaced with the catalyst provided in comparative example 3 with an equal loading. The other steps are completely the same as in application example 1.

[0246] Comparative Application Example 4

[0247] This application example provides a membrane electrode for PEM water electrolysis. The only difference from application example 1 is that the dual-site supported noble metal catalyst provided in example 1 is replaced with the catalyst provided in comparative example 4 with an equal loading. The other steps are completely consistent with application example 1.

[0248] Comparative Application Example 5

[0249] This application example provides a membrane electrode for PEM water electrolysis. The only difference from application example 1 is that the dual-site supported noble metal catalyst provided in example 1 is replaced with the catalyst provided in comparative example 5 with an equal loading. The other steps are completely the same as in application example 1.

[0250] Comparative Application Example 6

[0251] This application example provides a membrane electrode for PEM water electrolysis. The only difference from application example 1 is that the dual-site supported noble metal catalyst provided in example 1 is replaced with the catalyst provided in comparative example 6 with an equal loading. The other steps are completely consistent with application example 1.

[0252] Test Example 3

[0253] Multi-channel device performance testing

[0254] Test samples: PEM membrane electrodes for water electrolysis provided in Application Examples 1-9 and PEM membrane electrodes for water electrolysis provided in Comparative Application Examples 1-6.

[0255] Test method:

[0256] (1) Assembly of the electrolytic cell: Assemble the above samples in the following order: insulating end plate, cathode plate, 0.15mm gasket, carbon paper, membrane electrode (CCM), 2.05mm gasket, titanium felt, titanium mesh and anode plate. Tighten the electrolytic cell diagonally with a torque wrench (3N·m) and clamp the electrode clamps.

[0257] (2) Polarization performance test method: During the PEMWE test, the program was set to record the current density sequentially from a low current density of 0.025 A / cm². 2 The cell voltage at a high current density of 6 A / cm² was plotted as a function of the current density.

[0258] (3) Electrochemical stability was tested under PEMWE operating conditions using the chronopotential method. The test was conducted at a temperature of 80℃ and a current density of 2A / cm². 2 A 180-hour stability test was conducted. Real-time current and voltage values ​​were recorded during the stability test.

[0259] The test results are shown in Tables 3 and 4 below. Figures 5-6 As shown:

[0260] Table 3

[0261]

[0262]

[0263] Table 4

[0264]

[0265]

[0266] As shown in Tables 3-4 above and below Figures 5-6 As shown, the dual-site catalyst exhibits significantly lower charge transfer impedance, demonstrating its faster electrochemical oxygen evolution reaction kinetics due to the concerted reaction pathway of charge-mass separation.

[0267] In summary, this invention redesigns and adjusts the catalyst structure from the perspective of actual working conditions, constructing an anode catalyst structure with dual-site synergistic reaction. It separates the ionomer adsorption sites from the active sites, improving the exposure of active sites while building a stable proton transport channel. Ultimately, it improves catalyst utilization and electrolysis efficiency through a highly efficient and stable catalyst / ionomer interface, and reduces the cost of PEM anode catalyst for water electrolysis.

[0268] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A dual-site supported noble metal catalyst, characterized in that, The dual-site supported noble metal catalyst includes a noble metal oxide and a hydrophilic oxide with a surface rich in hydroxyl groups coated in the noble metal oxide; The surface-rich hydroxyl-rich hydrophilic oxide is prepared by the following steps: The hydrophilic oxide is immersed in a modification solution, then washed and dried to obtain the hydrophilic oxide with hydroxyl-rich surface; wherein the modification solution includes any one of hydrogen peroxide, a combination of hydrogen peroxide and a strong base, or a combination of hydrogen peroxide and a catalyst for the Fenton reaction. The strong base includes any one or a combination of at least two of sodium hydroxide, potassium hydroxide, lithium hydroxide, cesium hydroxide, or rubidium hydroxide; the catalyst for the Fenton reaction includes any one or a combination of at least two of ferrous chloride, ferrous nitrate, or ferrous sulfate. The soaking temperature is 70~90℃, and the soaking time is 20~120 min.

2. The dual-site supported noble metal catalyst according to claim 1, characterized in that, The noble metal oxide is selected from any one or a combination of at least two of ruthenium oxide, rhodium oxide, iridium oxide, or platinum oxide.

3. The dual-site supported noble metal catalyst according to claim 2, characterized in that, The noble metal oxide is iridium oxide.

4. The dual-site supported noble metal catalyst according to claim 1, characterized in that, The loading of the noble metal oxide is 10~70 wt%.

5. The dual-site supported noble metal catalyst according to claim 1, characterized in that, The hydrophilic oxide includes any one or a combination of at least two of titanium oxide, niobium oxide, tin oxide, or silicon oxide.

6. The dual-site supported noble metal catalyst according to claim 1, characterized in that, The hydrophilic oxide has a particle size of 10 nm to 1 μm.

7. The dual-site supported noble metal catalyst according to claim 1, characterized in that, The hydroxyl content in the hydrophilic oxide with hydroxyl-rich surface is 25-75%.

8. The dual-site supported noble metal catalyst according to claim 1, characterized in that, The hydrophilic oxide has a mass percentage of 0.5-5% in the modified solution.

9. The dual-site supported noble metal catalyst according to claim 1, characterized in that, The modified solution contains 3-30% hydrogen peroxide by mass.

10. The dual-site supported noble metal catalyst according to claim 1, characterized in that, The modified solution contains 1-25% by mass of strong alkali.

11. The dual-site supported noble metal catalyst according to claim 1, characterized in that, The modified solution contains 5-50% by mass of the catalyst used for the Fenton reaction.

12. A method for preparing a dual-site supported noble metal catalyst according to any one of claims 1 to 11, characterized in that, The preparation method of the dual-site supported noble metal catalyst includes the following steps: (1) The hydrophilic oxide with hydroxyl-rich surface is ultrasonically dispersed into an alcohol solution, a precursor solution of noble metal is added dropwise, and the mixture is dried after stirring to obtain a solid mixture; (2) The molten salt and the solid mixture obtained in step (1) are mixed and ground to obtain the ground product; (3) The grinding product obtained in step (2) is calcined to obtain the calcined product; the calcined product is then ultrasonically dispersed in an aqueous solution, centrifuged and washed, and then dried and ground to obtain the dual-site supported noble metal catalyst.

13. The method for preparing the dual-site supported noble metal catalyst according to claim 12, characterized in that, In step (1), the mass ratio of the metal element in the surface-rich hydrophilic oxide to the noble metal in the precursor is 1:(0.15~3.35).

14. The method for preparing the dual-site supported noble metal catalyst according to claim 12, characterized in that, In step (1), the mass-to-volume ratio of the hydrophilic oxide with hydroxyl-rich surface to the alcohol solution is 1 g:(100~150) mL.

15. The method for preparing the dual-site supported noble metal catalyst according to claim 12, characterized in that, In step (1), the mass-to-volume ratio of the precursor of the noble metal to the alcohol solution in the precursor solution of the noble metal is 1 g:(10~50) mL.

16. The method for preparing the dual-site supported noble metal catalyst according to claim 12, characterized in that, In step (1), the alcohol solution is isopropanol.

17. The method for preparing the dual-site supported noble metal catalyst according to claim 12, characterized in that, In step (1), the precursor of the noble metal includes any one or a combination of at least two of ruthenic acid, rhodium chlorochloride, iridium chlorochloride, ruthenic trichloride, iridium acetate, iridium acetylacetonate, or chloroplatinic acid.

18. The method for preparing the dual-site supported noble metal catalyst according to claim 12, characterized in that, In step (1), the stirring temperature is 40~60℃ and the stirring time is 1~3 h.

19. The method for preparing the dual-site supported noble metal catalyst according to claim 12, characterized in that, In step (1), the drying temperature is 60~90℃ and the drying time is 3~5 h.

20. The method for preparing the dual-site supported noble metal catalyst according to claim 12, characterized in that, In step (2), the mass ratio of the molten salt to the solid mixture is (1.43~19.14):

1.

21. The method for preparing the dual-site supported noble metal catalyst according to claim 20, characterized in that, In step (2), the mass ratio of the molten salt to the solid mixture is (4.78~19.14):

1.

22. The method for preparing the dual-site supported noble metal catalyst according to claim 12, characterized in that, In step (2), the grinding speed is 100~300 rpm, the grinding time is 0.5~2 h, and the particle size of the grinding product obtained by grinding is 300~500 nm.

23. The method for preparing the dual-site supported noble metal catalyst according to claim 12, characterized in that, In step (3), the calcination temperature is 250~450℃, the calcination time is 0.5~2 h, and the calcination heating rate is 5~15℃ / min.

24. The method for preparing the dual-site supported noble metal catalyst according to claim 12, characterized in that, In step (3), the number of centrifugal washing cycles is 3 to 6.

25. The method for preparing the dual-site supported noble metal catalyst according to claim 12, characterized in that, In step (3), the drying temperature is 60~80℃ and the drying time is 4~6 h.

26. The method for preparing the dual-site supported noble metal catalyst according to claim 12, characterized in that, In step (3), the grinding speed is 100~300 rpm and the grinding time is 0.5~2 h.

27. The method for preparing the dual-site supported noble metal catalyst according to claim 12, characterized in that, In step (3), the particle size of the dual-site supported noble metal catalyst is 10 nm to 1 μm.

28. The use of a dual-site supported noble metal catalyst according to any one of claims 1 to 11 in the preparation of an anode catalyst for PEM water electrolysis, a membrane electrode for PEM water electrolysis, or an electrolyzer for PEM water electrolysis.

29. A membrane electrode for PEM water electrolysis, characterized in that, The membrane electrode for PEM water electrolysis includes a proton exchange membrane and an anode catalyst layer and a cathode catalyst layer disposed on both sides of the proton exchange membrane; wherein, the anode catalyst layer includes the dual-site supported noble metal catalyst according to any one of claims 1 to 11.

30. The membrane electrode for PEM water electrolysis according to claim 29, characterized in that, The loading of noble metal elements in the anode catalyst layer is 0.100~1.000 mg / cm³. 2 .

31. The membrane electrode for PEM water electrolysis according to claim 29, characterized in that, The anode catalyst layer also includes ionomers.

32. The membrane electrode for PEM water electrolysis according to claim 31, characterized in that, The ionomer includes any one or a combination of at least two of perfluorosulfonic acid, sulfonated polyether ether ketone resin, or sulfonated trifluorostyrene resin.

33. The membrane electrode for PEM water electrolysis according to claim 32, characterized in that, The ionomer is perfluorosulfonic acid.

34. The membrane electrode for PEM water electrolysis according to claim 29, characterized in that, The loading of noble metal elements in the cathode catalyst layer is 0.100~1.000 mg / cm³. 2 .

35. The membrane electrode for PEM water electrolysis according to claim 29, characterized in that, The proton exchange membrane is a 115 proton exchange membrane.

36. A method for preparing a membrane electrode for PEM water electrolysis according to any one of claims 29 to 35, characterized in that, The preparation method of the membrane electrode for PEM water electrolysis includes the following steps: A dual-site supported noble metal catalyst, an ionomer solution, water, and alcohol were mixed, stirred and dispersed, and then degassed after ball milling to obtain an anode catalyst slurry. The anode catalyst layer slurry is coated onto one side of the transfer substrate and dried to form the anode catalyst layer. The cathode catalyst layer slurry is coated onto the other side of the transfer substrate and dried to form the cathode catalyst layer. The anode catalyst layer and the cathode catalyst layer are transferred to both sides of the proton exchange membrane by hot pressing to obtain the membrane electrode for PEM water electrolysis.

37. The method for preparing the membrane electrode for PEM water electrolysis according to claim 36, characterized in that, The dual-site supported noble metal catalyst accounts for 15-40% of the total mass of the anode catalyst layer slurry, and the ionomer solution accounts for 5-40% of the mass of the dual-site supported noble metal catalyst; the solid content of the ionomer solution is 15-20 wt%.

38. The method for preparing a membrane electrode for PEM water electrolysis according to claim 36, characterized in that, The alcohol is a monohydric liquid alcohol of C1 to C8 and / or a polyhydric liquid alcohol of C1 to C8.

39. The method for preparing a membrane electrode for PEM water electrolysis according to claim 38, characterized in that, The alcohol is selected from any one or a combination of at least two of ethanol, n-propanol, isopropanol, or propylene glycol.

40. The method for preparing a membrane electrode for PEM water electrolysis according to claim 36, characterized in that, The mass ratio of water to alcohol is (5~8):(2~5).

41. The method for preparing the membrane electrode for PEM water electrolysis according to claim 36, characterized in that, The ball milling conditions include: using 2.0~4.5 mm ZrO2 ball milling beads, constant temperature ball milling at 15~25℃, rotation speed of 300~1000 rpm, and time of 2~12 h.

42. An electrolytic cell for PEM water electrolysis, characterized in that, The electrolytic cell for PEM water electrolysis includes the membrane electrode for PEM water electrolysis as described in any one of claims 29 to 35.

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