Method for inhibiting poisoning of anode catalyst for PEM electrolyzed water, modified oxygen evolution catalyst and application

Abstract

The invention provides a method for inhibiting poisoning of an anode catalyst for PEM electrolyzed water, a modified oxygen evolution catalyst and application, and relates to the technical field of proton exchange membrane electrolyzed water. The method comprises the following steps: mixing and stirring an oxygen evolution catalyst and an auxiliary modifier in a solvent to obtain a mixed solution I; wherein the auxiliary modifier comprises hydrogen peroxide; mixing the mixed solution I with a modifier, and performing reflux heating to obtain a mixed solution II; wherein the modifier comprises any one or a combination of at least two of a reagent containing acid radical ions, thiourea, phosphide or phosphide; and removing the solvent in the mixed solution II to obtain the modified oxygen evolution catalyst. After the surface of the oxygen evolution catalyst is modified, the strong coordination effect of ionomer sulfonic acid sites is inhibited, a dynamic adjustable hydrogen bond network is constructed, efficient gas transmission is promoted, and finally high-working-condition active expression and long-life stable operation of the catalyst are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts for electrolyzed water anodes, and particularly relates to a method for inhibiting the poisoning of an anode catalyst for PEM electrolyzed water, a modified oxygen evolution catalyst, and applications thereof. Background Art

[0002] Proton exchange membrane electrolyzed water (PEMWE) has become a key technology for current green hydrogen production due to its advantages of high energy conversion efficiency, fast response speed, high-purity hydrogen production, and clean and pollution-free characteristics, and is widely used in fields such as energy storage, transportation, and industrial production. The membrane electrode assembly (MEA) is one of the core components of PEM electrolyzed water hydrogen production technology, and is usually composed of a proton exchange membrane (PEM), a catalyst layer (CL), and a porous transport layer (PTL). Among them, the catalyst layer is the core place for the electrochemical reaction of multiphase mass transfer and energy conversion, and is crucial for PEM electrolyzed water hydrogen production. The electrochemical performance and stability of the catalyst layer mainly depend on the constructed electrode interface structure, that is, the catalyst / ionomer interface, and it is necessary to balance the processes of proton, electron, and water / gas transport simultaneously.

[0003] The ionomer in the electrode structure not only undertakes the binder function - constructing a stable electrode matrix by fixing catalyst particles, but also plays a key proton conduction role as a solid electrolyte. However, the adsorption of excessive ionomers will cover the catalyst active sites, triggering a "poisoning effect"; at the same time, the too-thick ionomer layer at the interface will seriously block the mass transfer process of the reaction gas products, causing the accumulation of local pressure gradients, and ultimately affecting the long-term mechanical stability of the electrode structure. Constructing an efficient catalyst / ionomer interface structure is the core element for achieving high catalytic activity and excellent durability of PEM electrolyzers.

[0004] The basic research on the catalyst / ionomer interface in the current PEM electrolyzed water system is still lacking. It is worth noting that the traditional interface regulation strategies directly transplanted from the fuel cell system have significant limitations - the complex three-phase interface construction process and batch instability seriously restrict the feasibility of its large-scale production. At the same time, different catalyst structure systems also restrict the effective reproduction of these regulation means. This highlights the urgency of developing innovative interface engineering technologies, especially the need to establish a new method system that takes into account precise regulation at the nanoscale and the feasibility of macroscale preparation, so as to break through the key bottleneck restricting the industrial development of PEM electrolyzed water technology.

[0005] Fuel cells have discovered this phenomenon earlier. The literature [ACS Energy Lett., 2018, 3: 618 - 621] found that since macromolecules such as ionomers are difficult to penetrate into the internal pores of mesoporous carbon supports, the Pt catalyst supported on mesoporous carbon has a significantly lower ionomer coverage and a higher active site exposure compared to the Pt catalyst supported on non-porous carbon. Therefore, Pt particles are deposited inside the mesoporous carbon support to reduce their direct contact with ionomers.

[0006] CN116925576A discloses a relatively simple method for modifying carbon supports. By modifying the carbon supports with small molecule organic acids, the anchoring efficiency of noble metal Pt in the pores is increased, and ionomer poisoning is reduced. It optimizes the morphology control of the support, but the above method still cannot avoid the poisoning effect of ionomers on the catalyst. Ionomers will inevitably penetrate into the interior of the pores, accompanied by serious poisoning of the Pt nanoparticles on the outer surface. And the preparation of mesoporous carbon supports is relatively cumbersome, accompanied by a large amount of post-treatment sewage, and batch production cannot be formed.

[0007] CN116613326A discloses a method for preparing a membrane electrode by layer-by-layer printing different catalyst layers. The inkjet printing ink for the catalyst layer consists only of a solvent and a catalyst. By adjusting the process of electrode preparation, a three-phase reaction interface is constructed from a macroscopic perspective, avoiding the influence of catalyst poisoning by ionomers. However, there is still a macroscopic interface between ionomers / catalysts in the prepared catalyst layer, and the poisoning effect of ionomers on the Pt catalyst cannot be avoided. At the same time, the operation of inkjet printing is complex and not conducive to large-scale preparation.

[0008] At the same time, modifying the Pt and ionomer interface with ionic liquids [ACS Catal., 2020, 10(14): 7691] has been proven to be an effective method to mitigate the Pt catalyst poisoning effect related to the sulfonic acid groups of ionomers in the rotating disk electrode technique. However, it is very difficult to further apply it to real membrane electrodes, facing many difficulties and challenges.

[0009] CN113314722A utilizes the strong interaction between high steric hindrance hydroxyl groups and the sulfonic acid groups of ionomers to construct a "reversible barrier layer" of high steric hindrance alcohol compounds around the sulfonic acid groups of ionomers. The large steric hindrance alcohol compounds are used to reduce the direct contact between the sulfonic acid groups of ionomers and the Pt surface, so as to mitigate the poisoning of the -SO3H groups of ionomers on the Pt-based catalyst and improve the performance of the fuel cell membrane electrode. However, this alcohol additive is not suitable for the high working condition potential environment of water electrolysis and cannot stably exist on the electrode surface.

[0010] However, the above design concept does not fundamentally solve the problem of ionomer adsorption. It only restricts the ionomer poisoning problem through physical isolation or process adjustment, lacking chemical thinking at the molecular level. At the same time, the operation process is relatively complex and there is no possibility of scale-up production. Meanwhile, PEM electrolyzed water and fuel cells have different working conditions, and more complex interfacial reactions and hydrothermal effects need to be considered.

[0011] In view of this, the present invention is specifically proposed. Summary of the Invention

[0012] The object of the present invention is to provide a method for inhibiting the poisoning of an anode catalyst for PEM electrolyzed water, a modified oxygen evolution catalyst, and an application. The present invention optimizes the oxygen evolution catalyst / ionomer interface by adopting a surface modification strategy of a modifier for the catalyst, effectively inhibits the strong adsorption behavior of the sulfonic acid group of the ionomer, significantly reduces the poisoning effect of the catalyst active site, constructs a dynamically adjustable hydrogen bond network, promotes efficient gas transmission, and finally realizes the high-condition activity expression and long-life stable operation of the catalyst.

[0013] In order to achieve the above object of the present invention, the following technical solutions are specifically adopted:

[0014] In the first aspect, the present invention provides a method for inhibiting the poisoning of an anode catalyst for PEM electrolyzed water, and the method includes the following steps:

[0015] Mix and stir an oxygen evolution catalyst and a co-modifier in a solvent to obtain a first mixed solution; wherein, the co-modifier includes hydrogen peroxide.

[0016] Mix the first mixed solution and a modifier, and heat by refluxing to obtain a second mixed solution; wherein, the modifier includes any one or a combination of at least two of a reagent containing an acid root ion, thiourea, a phosphide, or a phosphine compound.

[0017] Remove the solvent in the second mixed solution to obtain a modified oxygen evolution catalyst.

[0018] Preferably, the oxygen evolution catalyst includes a noble metal-based catalyst; wherein, the noble metal-based catalyst includes an iridium-based catalyst and / or a ruthenium-based catalyst.

[0019] Preferably, the oxygen evolution catalyst is a composite noble metal catalyst, and the composite noble metal catalyst includes a noble metal oxide catalyst and a support oxide.

[0020] Preferably, the noble metal oxide catalyst is selected from ruthenium oxide and / or iridium oxide.

[0021] Preferably, the support oxide is selected from titanium oxide.

[0022] Preferably, the mass ratio of the noble metal oxide catalyst to the support oxide is (0.42 to 9):1.

[0023] Preferably, the composite noble metal catalyst is prepared by the following steps:

[0024] (a) Dispersing the support oxide in an alcohol solvent, dropping a noble metal precursor solution, stirring and dispersing, and then drying to obtain a solid mixture;

[0025] (b) Mixing and grinding the solid mixture and the molten metal salt to obtain a ground product;

[0026] (c) Calcining, washing, drying and grinding the ground product to obtain the composite noble metal catalyst.

[0027] Preferably, in step (a), the mass-volume ratio of the support oxide to the alcohol solvent is 1 g:(100 to 150) mL.

[0028] Preferably, in step (a), the alcohol solvent is selected from isopropanol.

[0029] Preferably, in step (a), the concentration of the noble metal precursor solution is 0.01 to 6 M.

[0030] Preferably, in step (a), the noble metal precursor solution is selected from noble metal chlorate solutions; wherein, the noble metal chlorate solution includes iridium chlorate solution and / or ruthenium chlorate solution; the solvent of the noble metal precursor solution is selected from any one or a combination of at least two of water, methanol, ethanol, isopropanol or ethylene glycol.

[0031] Preferably, in step (a), the stirring and dispersing time is 1 to 3 h.

[0032] Preferably, in step (a), the drying temperature is 60 to 90 °C, and the drying time is 3 to 5 h.

[0033] Preferably, in step (b), the molten metal salt is selected from NaNO3.

[0034] Preferably, in step (b), the mass ratio of the metal element in the molten metal salt to the noble metal element in the solid mixture is (1.43 to 19.14):1, preferably (4.78 to 19.14):1.

[0035] Preferably, in step (c), the calcining temperature is 350 to 550 °C, the calcining time is 0.5 to 2 h, and the calcining heating rate is 5 to 15 °C / min.

[0036] Preferably, the mass ratio of the oxygen evolution catalyst to the co-modifier is 1:(0.05-1).

[0037] Preferably, the mass percentage of hydrogen peroxide in the solvent is 3-30%.

[0038] Preferably, the co-modifier further includes a catalyst for Fenton reaction.

[0039] Preferably, the mass percentage of the catalyst for Fenton reaction in the solvent is 1-20%.

[0040] Preferably, the catalyst for Fenton reaction is selected from any one or a combination of at least two of compounds of divalent iron, copper, manganese, and nickel.

[0041] Preferably, in the process of obtaining the first mixed solution, the temperature of the mixing and stirring is 50-80°C, and the time of the mixing and stirring is 0.5-3 h.

[0042] Preferably, the mass ratio of the oxygen evolution catalyst to the modifier is 1:(0.01-0.1).

[0043] Preferably, the reagent containing an acid root ion is selected from any one or a combination of at least two of nitric acid, phosphoric acid, sulfuric acid, oxalic acid, and lactic acid.

[0044] Preferably, the phosphide is a chloride of phosphorus, preferably phosphorus oxychloride.

[0045] Preferably, the phosphine compound is a chloride of phosphine, preferably phenylphosphonic dichloride.

[0046] Preferably, when the modifier is a reagent containing an acid root ion, the solvent is selected from isopropanol.

[0047] Preferably, when the modifier is thiourea, the solvent is selected from water.

[0048] Preferably, when the modifier is a phosphide and / or a phosphine compound, the solvent is selected from n-hexane.

[0049] Preferably, the temperature of the reflux heating is 80-120°C, and the time of the reflux heating is 2-14 h.

[0050] Preferably, when the modifier is a reagent containing an acid root ion, the method further includes the following post-treatment steps:

[0051] After drying the second mixed solution at 80-120°C for 2-24 h, and then washing, an oxygen evolution catalyst modified with an acid root ion is obtained.

[0052] Preferably, when the modifier is thiourea, the method further includes the following post-treatment steps:

[0053] Mix the second mixture and the strong oxidant at 50 - 60 °C for 30 - 180 min, collect the solid precipitate by centrifugation, wash it, and then dry it at 80 - 120 °C for 2 - 24 h to obtain the oxygen evolution catalyst modified with sulfuric acid.

[0054] Preferably, the addition amounts of the strong oxidant and the catalyst are (0.1 - 20):1.

[0055] Preferably, the strong oxidant is selected from hydrogen peroxide and / or potassium permanganate.

[0056] Preferably, when the modifier is a phosphide and / or a phosphine compound, the method further includes the following post - treatment steps:

[0057] The second mixture is centrifuged to collect the solid precipitate, washed, and then dried at 80 - 120 °C for 2 - 24 h to obtain the oxygen evolution catalyst modified with phosphoric acid and / or phosphonic acid.

[0058] In a second aspect, the present invention provides a modified oxygen evolution catalyst, which is prepared by the method for inhibiting the poisoning of the anode catalyst for PEM electrolyzed water as described in the first aspect.

[0059] In a third aspect, the present invention provides an application of the modified oxygen evolution catalyst as described in the second aspect in the preparation of a membrane electrode for PEM electrolyzed water and / or an electrolytic cell for PEM electrolyzed water.

[0060] In a fourth aspect, the present invention provides a membrane electrode for PEM electrolyzed water, which includes a proton exchange membrane and anode catalyst layers and cathode catalyst layers disposed on both sides of the proton exchange membrane; wherein, the anode catalyst layer includes the modified oxygen evolution catalyst as described in the second aspect.

[0061] In a fifth aspect, the present invention provides an electrolytic cell for PEM electrolyzed water, which includes the membrane electrode for PEM electrolyzed water as described in the fourth aspect.

[0062] Compared with the prior art, the present invention has the following beneficial effects:

[0063] (1) Through the surface modification of the catalyst, the present invention effectively inhibits the strong adsorption behavior of the sulfonic acid groups of the ionomer, and significantly reduces the poisoning effect on the active sites of the catalyst.

[0064] (2) The present invention uses the surface modification layer to construct a dynamically adjustable hydrogen - bond network structure, which while ensuring the stable anchoring of the ionomer, constructs an efficient gas transport channel to achieve the synergistic optimization of the three - phase interface.

[0065] (3) The present invention significantly improves the utilization rate and stability of the electrode, providing a feasible technical path for reducing the cost of the anode catalyst for PEM water electrolysis. Description of the Drawings

[0066] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0067] Figure 1 FTIR diagram of the oxygen evolution catalyst modified by acid radical ions provided for Example 1.

[0068] Figure 2 Ionomer adsorption thickness - atomic force microscope diagram of the membrane electrode surface prepared by using the oxygen evolution catalyst modified by acid radical ions provided for Application Example 1.

[0069] Figure 3 Ionomer adsorption thickness - atomic force microscope diagram of the membrane electrode surface prepared by using the unmodified oxygen evolution catalyst provided for Comparative Application Example 1.

[0070] Figure 4 Sheet resistance test diagram of the membrane electrodes prepared for Application Example 1 and Comparative Application Example 1.

[0071] Figure 5 PEM water electrolysis performance curve diagram of the membrane electrodes prepared for Application Example 1 and Comparative Application Example 1.

[0072] Figure 6 In-situ impedance spectrum diagram of the membrane electrodes prepared for Application Example 1 and Comparative Application Example 1. Detailed Description of the Invention

[0073] Unless otherwise defined herein, scientific and technical terms used in conjunction with the present invention shall have the meanings commonly understood by those of ordinary skill in the art. The meaning and scope of the terms should be clear. However, in any case of potential ambiguity, the definitions provided herein shall prevail over any dictionary or extrinsic definition. In this application, unless otherwise specified, the use of "or" means "and / or". In addition, the use of the term "including" and other forms is non-restrictive.

[0074] It should be noted that specific details are set forth in the following description to facilitate a thorough understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar generalizations without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0075] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0076] In a first aspect, the present invention provides a method for inhibiting the poisoning of an anode catalyst for PEM electrolyzed water, and the method includes the following steps:

[0077] Mix and stir an oxygen evolution catalyst and a co-modifier in a solvent to obtain a first mixed solution; wherein, the co-modifier includes hydrogen peroxide.

[0078] Mix the first mixed solution and a modifier, and reflux and heat to obtain a second mixed solution; wherein, the modifier includes any one or a combination of at least two of a reagent containing an acid radical ion, thiourea, a phosphide or a phosphine compound.

[0079] Remove the solvent in the second mixed solution to obtain a modified oxygen evolution catalyst.

[0080] In the present invention, starting from the actual working conditions of PEM electrolyzed water, an innovative strategy of optimizing the oxygen evolution catalyst / ionomer interface through surface acid radical ion modification is proposed. This technical solution has the following characteristics: First, the strong adsorption behavior of the sulfonic acid group of the ionomer is effectively inhibited through surface acid radical ion modification, significantly reducing the poisoning effect on the active sites of the catalyst; Second, a dynamically adjustable hydrogen bond network structure is constructed by using the surface modification layer, while ensuring the stable anchoring of the ionomer, an efficient gas transport channel is constructed to realize the synergistic optimization of the three-phase interface. This interface engineering strategy significantly improves the utilization rate and stability of the electrode, providing a feasible technical path for reducing the cost of the anode catalyst for PEM electrolyzed water. The present invention provides a catalyst structure for the anode of PEM electrolyzed water and a preparation method thereof with low cost and easy operation at the molecular level.

[0081] As an optional implementation manner, the oxygen evolution catalyst includes a noble metal-based catalyst; wherein, the noble metal-based catalyst includes an iridium-based catalyst and / or a ruthenium-based catalyst.

[0082] As an optional implementation manner, the particle size of the oxygen evolution catalyst is 10 nm to 1 μm, and for example, it can be 10 nm, 20 nm, 40 nm, 50 nm, 100 nm, 150 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1 μm, etc.

[0083] As a preferred embodiment, the oxygen evolution catalyst is a composite noble metal catalyst, and the composite noble metal catalyst includes a noble metal oxide catalyst and a support oxide.

[0084] As a preferred embodiment, the noble metal oxide catalyst is selected from ruthenium oxide and / or iridium oxide.

[0085] As a preferred embodiment, the support oxide is selected from titanium oxide.

[0086] As a preferred embodiment, the particle size of the support oxide is 10 nm to 1 μm, and for example, it can be 10 nm, 20 nm, 40 nm, 50 nm, 100 nm, 150 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1 μm, etc.

[0087] As a preferred embodiment, the mass ratio of the noble metal oxide catalyst to the support oxide is (0.42 - 9):1, and for example, it can be 0.42:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, etc.

[0088] As a preferred embodiment, the composite noble metal catalyst is prepared by the following steps:

[0089] (a) Dispersing the support oxide in an alcohol solvent, dropping a noble metal precursor solution, stirring and dispersing, and then drying to obtain a solid mixture;

[0090] (b) Mixing and grinding the solid mixture with a molten metal salt to obtain a ground product;

[0091] (c) Calcining, washing, drying and grinding the ground product to obtain the composite noble metal catalyst.

[0092] As an alternative embodiment, in step (a), the mass - volume ratio of the support oxide to the alcohol solvent is 1 g:(100 - 150) mL, and for example, it can be 1 g:100 mL, 1 g:110 mL, 1 g:120 mL, 1 g:130 mL, 1 g:140 mL, 1 g:150 mL, etc.

[0093] As an alternative embodiment, in step (a), the alcohol solvent is selected from isopropyl alcohol.

[0094] As an alternative embodiment, in step (a), the concentration of the noble metal precursor solution is 0.01 to 6 M, for example, it can be 0.01 M, 0.02 M, 0.04 M, 0.05 M, 0.06 M, 0.08 M, 0.1 M, 0.2 M, 0.4 M, 0.5 M, 0.6 M, 0.8 M, 1 M, 2 M, 3 M, 4 M, 5 M, 6 M, etc.

[0095] As an alternative embodiment, in step (a), the noble metal precursor solution is selected from noble metal chlorate solutions; wherein, the noble metal chlorate solution includes iridium chlorate solution and / or ruthenium chlorate solution; the solvent of the noble metal precursor solution is selected from any one or a combination of at least two of water, methanol, ethanol, isopropanol or ethylene glycol.

[0096] As an alternative embodiment, in step (a), the time for stirring and dispersing is 1 to 3 h, for example, it can be 1 h, 1.2 h, 1.4 h, 1.6 h, 1.8 h, 2 h, 2.2 h, 2.4 h, 2.6 h, 2.8 h, 3 h, etc.

[0097] As an alternative embodiment, in step (a), the drying temperature is 60 to 90 °C, for example, it can be 60 °C, 65 °C, 70 °C, 75 °C, 80 °C, 85 °C, 90 °C, etc., and the drying time is 3 to 5 h, for example, it can be 3 h, 3.2 h, 3.4 h, 3.6 h, 3.8 h, 4 h, 4.2 h, 4.4 h, 4.6 h, 4.8 h, 5 h, etc.

[0098] As an alternative embodiment, in step (b), the molten metal salt is selected from NaNO3.

[0099] As an alternative embodiment, in step (b), the mass ratio of the metal element in the molten metal salt in the solid mixture to the mass of the noble metal element 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, 8:1, 10:1, 12:1, 14:1, 16:1, 18:1, 19.14:1, etc., and preferably (4.78 to 19.14):1.

[0100] As an alternative embodiment, in step (c), the calcination temperature is 350 - 550 °C, for example, it can be 350 °C, 380 °C, 400 °C, 420 °C, 450 °C, 460 °C, 480 °C, 500 °C, 520 °C, 540 °C, 550 °C, etc.; the calcination time is 0.5 - 2 h, for example, it can be 0.5 h, 0.6 h, 0.7 h, 1 h, 1.2 h, 1.4 h, 1.5 h, 1.6 h, 1.8 h, 2 h, etc.; the heating rate of the calcination is 5 - 15 °C / min, for example, it can be 5 °C / min, 6 °C / min, 8 °C / min, 10 °C / min, 12 °C / min, 14 °C / min, 15 °C / min, etc.

[0101] As an alternative embodiment, the mass ratio of the oxygen evolution catalyst to the co - modifier is 1:(0.05 - 1), for example, it can be 1:0.05, 1:0.06, 1:0.08, 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, etc.

[0102] As an alternative embodiment, the mass percentage content of hydrogen peroxide in the solvent is 3 - 30%, for example, it can be 3%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, etc.

[0103] As an alternative embodiment, the co - modifier further includes a catalyst for Fenton reaction.

[0104] As an alternative embodiment, the mass percentage content of the catalyst for Fenton reaction in the solvent is 1 - 20%, for example, it can be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, etc.

[0105] As an alternative embodiment, the catalyst for Fenton reaction is selected from any one or a combination of at least two of compounds of divalent iron, copper, manganese, and nickel.

[0106] As an alternative embodiment, the catalyst for Fenton reaction is selected from any one or a combination of at least two of ferric chloride, copper chloride, manganese chloride, or nickel chloride.

[0107] As an alternative embodiment, during the process of obtaining the first mixture, the temperature of the mixing and stirring is 50 to 80 °C, such as 50 °C, 55 °C, 60 °C, 65 °C, 70 °C, 75 °C, 80 °C, etc., and the time of the mixing and stirring is 0.5 to 3 h, such as 0.5 h, 0.6 h, 0.7 h, 1 h, 1.2 h, 1.4 h, 1.5 h, 1.6 h, 1.8 h, 2 h, 2.2 h, 2.4 h, 2.6 h, 2.8 h, 3 h, etc.

[0108] As an alternative embodiment, the mass ratio of the oxygen evolution catalyst to the modifier is 1:(0.01 to 0.1), such as 1:0.01, 1:0.02, 1:0.03, 1:0.04, 1:0.05, 1:0.06, 1:0.07, 1:0.08, 1:0.09, 1:0.1, etc.

[0109] As an alternative embodiment, the reagent containing an acid root ion is selected from any one or a combination of at least two of nitric acid, phosphoric acid, sulfuric acid, oxalic acid or lactic acid.

[0110] As an alternative embodiment, the phosphide is selected from phosphorus chlorides, preferably phosphorus oxychloride.

[0111] As an alternative embodiment, the phosphine compound is selected from phosphorus chlorides, preferably benzene phosphonic dichloride.

[0112] As an alternative embodiment, when the modifier is a reagent containing an acid root ion, the solvent is selected from isopropanol.

[0113] As an alternative embodiment, when the modifier is thiourea, the solvent is selected from water.

[0114] As an alternative embodiment, when the modifier is a phosphide and / or a phosphine compound, the solvent is selected from n-hexane.

[0115] As an alternative embodiment, the temperature of the reflux heating is 80 to 120 °C, such as 80 °C, 85 °C, 90 °C, 95 °C, 100 °C, 105 °C, 110 °C, 115 °C, 120 °C, etc., and the time of the reflux heating is 2 to 14 h, such as 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, 12 h, 13 h, 14 h, etc.

[0116] As an alternative embodiment, when the modifier is a reagent containing an acid root ion, the method further includes the following post-treatment steps:

[0117] After drying the second mixture at 80 to 120 °C for 2 to 24 h and then washing, an oxygen evolution catalyst modified with an acid root ion is obtained.

[0118] As an optional embodiment, when the modifier is thiourea, the method further includes the following post-treatment steps:

[0119] Mix the second mixed solution and a strong oxidant at 50 - 60 °C for 30 - 180 min, collect the solid precipitate by centrifugation, wash it, and then dry it at 80 - 120 °C for 2 - 24 h to obtain an oxygen evolution catalyst modified with sulfuric acid.

[0120] As an optional embodiment, the addition amounts of the strong oxidant and the catalyst are (0.1 - 20):1, and for example, they can be 0.1:1, 0.2:1, 0.4:1, 0.5:1, 0.6:1, 0.8:1, 1:1, 2:1, 4:1, 5:1, 6:1, 8:1, 10:1, 12:1, 14:1, 15:1, 16:1, 18:1, 20:1, etc.

[0121] As an optional embodiment, the strong oxidant is selected from hydrogen peroxide and / or potassium permanganate.

[0122] As an optional embodiment, when the modifier is a phosphide and / or a phosphine compound, the method further includes the following post-treatment steps:

[0123] Collect the solid precipitate from the second mixed solution by centrifugation, wash it, and then dry it at 80 - 120 °C for 2 - 24 h to obtain an oxygen evolution catalyst modified with phosphoric acid and / or phosphonic acid.

[0124] In a second aspect, the present invention provides a modified oxygen evolution catalyst, which is prepared by the method for inhibiting the poisoning of the anode catalyst for PEM electrolytic water as described in the first aspect.

[0125] In a third aspect, the present invention provides an application of the modified oxygen evolution catalyst as described in the second aspect in the preparation of a membrane electrode for PEM electrolytic water and / or an electrolytic cell for PEM electrolytic water.

[0126] In a fourth aspect, the present invention provides a membrane electrode for PEM electrolytic water, which 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 modified oxygen evolution catalyst as described in the second aspect.

[0127] As an optional embodiment, the anode catalyst layer further includes an ionomer.

[0128] As an optional embodiment, the ionomer is selected from one or more mixtures having a proton conduction function, and preferably perfluorosulfonic acid.

[0129] As an alternative embodiment, the loading of the noble metal element in the anode catalyst layer is 0.100 to 1.000 mg / cm 2 , for example, it can be 0.100 mg / cm 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 and so on.

[0130] As an alternative embodiment, the loading of the noble metal element in the cathode catalyst layer is 0.100 to 1.000 mg / cm 2 , for example, it can be 0.100 mg / cm 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 and so on.

[0131] As an alternative embodiment, the proton exchange membrane is a 115 proton exchange membrane.

[0132] As an alternative embodiment, the method for preparing the membrane electrode for PEM electrolyzed water includes the following steps:

[0133] Mix the modified oxygen evolution catalyst, ionomer solution, water and alcohol, stir and disperse, defoam after ball milling to obtain the anode catalyst layer slurry; coat the anode catalyst layer slurry on one side of the transfer substrate, and after drying, form the anode catalyst layer; coat the cathode catalyst layer slurry on the other side of the transfer substrate, and after drying, form the cathode catalyst layer; transfer the anode catalyst layer and the cathode catalyst layer to both sides of the proton exchange membrane by thermal transfer printing respectively to obtain the membrane electrode for PEM electrolyzed water.

[0134] As an alternative embodiment, the modified oxygen evolution catalyst accounts for 15 to 40% of the total mass of the anode catalyst layer slurry, and can be, for example, 15%, 16%, 18%, 20%, 22%, 24%, 25%, 26%, 28%, 30%, 32%, 34%, 35%, 36%, 38%, 40%, etc.

[0135] As an alternative embodiment, the ionomer solution is 5 to 40% of the mass of the composite noble metal catalyst, and can be, for example, 5%, 6%, 8%, 10%, 12%, 15%, 16%, 18%, 20%, 22%, 24%, 25%, 26%, 28%, 30%, 32%, 34%, 35%, 36%, 38%, 40%, etc.

[0136] As an alternative embodiment, the alcohol is a liquid alcohol, preferably any one or a combination of at least two of ethanol, n-propanol, isopropanol or propylene glycol.

[0137] As an alternative embodiment, the mass ratio of water to alcohol is (5 to 8):(2 to 5);

[0138] Among them, "5 to 8" can be, for example, 5, 5.5, 6, 6.5, 7, 7.5, 8, etc.;

[0139] Among them, "2 to 5" can be, for example, 2, 2.5, 3, 3.5, 4, 4.5, 5, etc.

[0140] As an alternative embodiment, the conditions for ball milling include: ZrO₂ ball milling beads with a diameter of 2.0 to 4.5 mm, constant temperature ball milling at 15 to 25 °C, a rotation speed of 300 to 1000 rpm, and a time of 2 to 12 h.

[0141] As an alternative embodiment, the particle size of the ZrO₂ ball milling beads is 2.0 to 4.5 mm, and can be, 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.

[0142] As an alternative embodiment, the temperature of the ball milling is 15 to 25 °C, and can be, for example, 15 °C, 16 °C, 17 °C, 18 °C, 19 °C, 20 °C, 21 °C, 22 °C, 23 °C, 24 °C, 25 °C, etc.

[0143] As an alternative embodiment, the rotation speed of the ball milling is 300 - 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.

[0144] As an alternative embodiment, the time of the ball milling is 2 - 12 h, for example, it can be 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h, 5.5 h, 6 h, 6.5 h, 7 h, 7.5 h, 8 h, 8.5 h, 9 h, 9.5 h, 10 h, 10.5 h, 11 h, 11.5 h, 12 h, etc.

[0145] In a fifth aspect, the present invention provides an electrolytic cell for PEM electrolysis of water, and the electrolytic cell for PEM electrolysis of water includes the membrane electrode for PEM electrolysis of water as described in the fourth aspect.

[0146] As an alternative embodiment, the electrolytic cell for PEM electrolysis of water sequentially includes an insulating end plate, a cathode plate, a first gasket, carbon paper, the membrane electrode (CCM) for PEM electrolysis of water as described in the fourth aspect, a second gasket, titanium felt, titanium mesh, and an anode plate.

[0147] As an alternative embodiment, the first gasket is a 0.15 mm gasket.

[0148] As an alternative embodiment, the second gasket is a 2.05 mm gasket.

[0149] The present invention will be further described below through examples. Unless otherwise specified, the materials in the examples are prepared according to existing methods or directly purchased from the market.

[0150] Example 1

[0151] This example provides a method for inhibiting the poisoning of the anode catalyst for PEM electrolysis of water, and the method includes the following steps:

[0152] S1. Preparation of the oxygen evolution catalyst:

[0153] 1 g of TiO2 (particle size 50 nm) was ultrasonically dispersed in 120 mL of isopropanol, and then 100 mL of a precursor solution H2IrCl6 with a concentration of 0.0446 M was added dropwise. The mixture was stirred at 60 °C for 2 h. After forming a uniformly dispersed solution, it was dried in an oven at 75 °C for 4 h to form a solid mixture (where the mass ratio of Ir to Ti was 1.43:1). The solid mixture and NaNO3 were ground evenly together to obtain a ground product (where the mass ratio of Na to Ir was 4.78:1). The ground product was calcined at 450 °C for 1 h with a heating rate of 10 °C / min, and then naturally cooled to room temperature. It was ultrasonically dispersed in an aqueous solution and centrifuged and washed with water 5 times to remove excessive impurity salts. After drying, it was ground evenly to obtain the catalyst TiO2@IrO2 with the required particle size (particle size 54 nm).

[0154] S2, Acid radical ion modification:

[0155] The oxygen evolution catalyst TiO2@IrO2 prepared from 1 g of S1 was dispersed in 50 mL of methanol, and 2 mL of hydrogen peroxide (the content of H2O2 in this hydrogen peroxide was 5 wt%) was added. The mixture was stirred at 60 °C for 1 h; 10 mL of nitric acid (concentration 0.5 wt%) was added, and the mixture was refluxed and stirred at 90 °C for 8 h; after drying at 100 °C for 12 h, it was washed several times with methanol and deionized water respectively to obtain the oxygen evolution catalyst modified with nitrate ions.

[0156] As Figure 1 shown, the FTIR spectrum of the surface-modified oxygen evolution catalyst TiO2@IrO2. After the surface modification of this catalyst, it has an obvious peak pattern of NO3 - monodentate coordination.

[0157] Example 2

[0158] This example provides a method for inhibiting the poisoning of the anode catalyst for PEM electrolyzed water. The method includes the following steps:

[0159] S1, Preparation of oxygen evolution catalyst:

[0160] 1 g of TiO2 (particle size: 100 nm) was ultrasonically dispersed in 120 mL of isopropanol, and then 10 mL of a 0.2 M precursor solution H2IrCl6 was added dropwise. After stirring at 60 °C for 2 h to form a uniformly dispersed solution, it was dried in an oven at 75 °C for 4 h to form a solid mixture (where the mass ratio of Ir to Ti was 0.64:1). The solid mixture and NaNO3 were ground together evenly to obtain a ground product (where the mass ratio of Na to Ir was 19.14:1). The ground product was calcined at 450 °C for 1 h with a heating rate of 10 °C / min, and then naturally cooled to room temperature. It was ultrasonically dispersed in an aqueous solution and centrifuged and washed with water 5 times to remove excess impurity salts. After drying, it was ground evenly to obtain the catalyst TiO2@IrO2 with the desired particle size (particle size: 102 nm).

[0161] S2. Acid radical ion modification:

[0162] The oxygen evolution catalyst TiO2@IrO2 prepared from 1 g of S1 was dispersed in 50 mL of methanol, and 4 mL of hydrogen peroxide (the content of H2O2 in this hydrogen peroxide was 10 wt%) and 0.04 g of the catalyst for Fenton reaction (ferrous chloride) were added. It was stirred at 70 °C for 1.5 h; 10 mL of sulfuric acid (concentration: 0.5 wt%) was added, and it was refluxed and stirred at 100 °C for 10 h; after drying at 120 °C for 8 h, it was washed several times with methanol and deionized water to obtain the oxygen evolution catalyst modified with sulfate ions.

[0163] Example 3

[0164] This example provides a method for inhibiting the poisoning of the anode catalyst for PEM electrolyzed water, and the method includes the following steps:

[0165] S1. Preparation of oxygen evolution catalyst:

[0166] 1 g of TiO2 (particle size: 150 nm) was ultrasonically dispersed in 120 mL of isopropanol, and then 20 mL of a 2 M precursor solution H2IrCl6 was added dropwise. After stirring at 60 °C for 2 h to form a uniformly dispersed solution, it was dried in an oven at 75 °C for 4 h to form a solid mixture (where the mass ratio of Ir to Ti was 12.86:1). The solid mixture and NaNO3 were ground together evenly to obtain a ground product (where the mass ratio of Na to Ir was 12.75:1). The ground product was calcined at 450 °C for 1 h with a heating rate of 10 °C / min, and then naturally cooled to room temperature. It was ultrasonically dispersed in an aqueous solution and centrifuged and washed with water 5 times to remove excess impurity salts. After drying, it was ground evenly to obtain the catalyst TiO2@IrO2 with the desired particle size (particle size: 158 nm).

[0167] S2. Acid radical ion modification:

[0168] Disperse 1 g of the oxygen evolution catalyst TiO2@IrO2 prepared from S1 in 50 mL of methanol, add 8 mL of hydrogen peroxide (the content of H2O2 in this hydrogen peroxide is 10 wt%) and 0.1 g of the catalyst for Fenton reaction (nickel chloride), and stir at 80 °C for 2 h; add 20 mL of phosphoric acid (concentration is 0.5 wt%), and reflux and stir at 120 °C for 6 h; after drying at 80 °C for 18 h, wash several times with methanol and deionized water respectively to obtain the oxygen evolution catalyst modified by phosphate ions.

[0169] Example 4

[0170] This example provides a method for inhibiting the poisoning of the anode catalyst for PEM water electrolysis. The difference from Example 1 is only that the preparation of S1 is not carried out, and the oxygen evolution catalyst TiO2@IrO2 in S2 is replaced with a commercially available IrO2 oxygen evolution catalyst of the same mass, and other steps are exactly the same as those in Example 1.

[0171] Example 5

[0172] This example provides a method for inhibiting the poisoning of the anode catalyst for PEM water electrolysis. The difference from Example 1 is only that the preparation of S1 is not carried out, and the oxygen evolution catalyst TiO2@IrO2 in S2 is replaced with a commercially available RuO2 oxygen evolution catalyst of the same mass, and other steps are exactly the same as those in Example 1.

[0173] Example 6

[0174] This example provides a method for inhibiting the poisoning of the anode catalyst for PEM water electrolysis. The method includes the following steps:

[0175] S1. Preparation of the oxygen evolution catalyst:

[0176] Disperse 1 g of TiO2 (particle size is 50 nm) in 120 mL of isopropanol by ultrasonic wave, then dropwise add 100 mL of the precursor solution H2IrCl6 with a concentration of 0.0446 M, stir at 60 °C for 2 h, after forming a uniformly dispersed solution, place it in an oven at 75 °C and dry for 4 h to form a solid mixture (where the mass ratio of Ir to Ti is 1.43:1). Grind the solid mixture and NaNO3 evenly together to obtain a ground product (where the mass ratio of Na to Ir is 4.78:1). Calcinate the ground product at 450 °C for 1 h with a heating rate of 10 °C / min, then naturally cool to room temperature, disperse it in an aqueous solution by ultrasonic wave, and wash it by centrifugation 5 times to remove excessive impurity salts. After drying, grind it evenly to obtain the required particle size of the catalyst TiO2@IrO2 (particle size is 54 nm).

[0177] S2. Sulfuric acid modification:

[0178] Disperse 1 g of the oxygen evolution catalyst TiO2@IrO2 prepared from S1 in 50 mL of deionized water, add 2 mL of hydrogen peroxide (the content of H2O2 in this hydrogen peroxide is 5 wt%), and stir at 60 °C for 1 h; add 0.25 mL of thiourea, and reflux and stir at 90 °C for 8 h; cool to room temperature, then add 5 mL of hydrogen peroxide (the content of H2O2 in this hydrogen peroxide is 20 wt%) to promote the oxidation of the adsorbed sulfide; centrifuge to collect the solid precipitate, wash it several times with ethanol and deionized water, and then dry it at 100 °C for 12 h to obtain the sulfuric acid modified oxygen evolution catalyst.

[0179] Example 7

[0180] This example provides a method for inhibiting the poisoning of the anode catalyst for PEM water electrolysis, and the method includes the following steps:

[0181] S1. Preparation of the oxygen evolution catalyst:

[0182] Disperse 1 g of TiO2 (particle size of 100 nm) by ultrasonic dispersion in 120 mL of isopropanol, then dropwise add 10 mL of the precursor solution H2IrCl6 with a concentration of 0.2 M, stir at 60 °C for 2 h, after forming a uniformly dispersed solution, place it in an oven at 75 °C and dry for 4 h to form a solid mixture (where the mass ratio of Ir to Ti is 0.64:1). Grind the solid mixture and NaNO3 evenly together to obtain a ground product (where the mass ratio of Na to Ir is 19.14:1). Calcinate the ground product at 450 °C for 1 h with a heating rate of 10 °C / min, then naturally cool to room temperature, disperse it in an aqueous solution by ultrasonic wave, and wash it 5 times by centrifugation with water to remove excessive impurity salts. After drying, grind it evenly to obtain the catalyst TiO2@IrO2 with the required particle size (particle size of 102 nm).

[0183] S2. Sulfuric acid modification:

[0184] Disperse 1 g of the oxygen evolution catalyst TiO2@IrO2 prepared from S1 in 50 mL of deionized water, add 4 mL of hydrogen peroxide (the content of H2O2 in this hydrogen peroxide is 10 wt%) and 0.04 g of the catalyst for Fenton reaction (ferrous chloride), and stir at 70 °C for 1.5 h; add 0.2 mL of thiourea, and reflux and stir at 100 °C for 6 h; cool to room temperature, then add 2 g of potassium permanganate to promote the oxidation of the adsorbed sulfide; centrifuge to collect the solid precipitate, wash it several times with ethanol and deionized water, and then dry it at 120 °C for 8 h to obtain the sulfuric acid modified oxygen evolution catalyst.

[0185] Example 8

[0186] This example provides a method for inhibiting the poisoning of the anode catalyst for PEM water electrolysis, and the method includes the following steps:

[0187] S1. Preparation of oxygen evolution catalyst:

[0188] Disperse 1 g of TiO2 (particle size 150 nm) ultrasonically in 120 mL of isopropanol, then add dropwise 20 mL of the precursor solution H2IrCl6 with a concentration of 2 M, stir at 60 °C for 2 h. After forming a uniformly dispersed solution, dry it in an oven at 75 °C for 4 h to form a solid mixture (where the mass ratio of Ir to Ti is 12.86:1). Grind the solid mixture and NaNO3 together evenly to obtain a ground product (where the mass ratio of Na to Ir is 12.75:1). Calcinate the ground product at 450 °C for 1 h with a heating rate of 10 °C / min, then naturally cool it to room temperature, ultrasonically disperse it in an aqueous solution, and wash it by centrifugation with water 5 times to remove excess impurity salts. After drying, grind it evenly to obtain the oxygen evolution catalyst TiO2@IrO2 with the required particle size (particle size 158 nm).

[0189] S2. Sulfuric acid modification:

[0190] Disperse 1 g of the oxygen evolution catalyst TiO2@IrO2 prepared in S1 in 50 mL of deionized water, add 8 mL of hydrogen peroxide (the content of H2O2 in this hydrogen peroxide is 10 wt%) and 0.1 g of the catalyst for Fenton reaction (specific name: nickel chloride), stir at 80 °C for 2 h; add 0.3 mL of thiourea and reflux and stir at 120 °C for 12 h; cool to room temperature, then add 10 g of potassium permanganate to promote the oxidation of the adsorbed sulfide; centrifuge to collect the solid precipitate, wash it several times with ethanol and deionized water, and dry it at 80 °C for 18 h to obtain the sulfuric acid-modified oxygen evolution catalyst.

[0191] Example 9

[0192] This example provides a method for inhibiting the poisoning of the anode catalyst for PEM electrolyzed water. The difference from Example 6 is only that the preparation of S1 is not carried out, and the oxygen evolution catalyst TiO2@IrO2 in S2 is replaced with a commercially available IrO2 oxygen evolution catalyst of equal mass, and the other steps are exactly the same as those in Example 6.

[0193] Example 10

[0194] This example provides a method for inhibiting the poisoning of the anode catalyst for PEM electrolyzed water. The difference from Example 6 is only that the preparation of S1 is not carried out, and the oxygen evolution catalyst TiO2@IrO2 in S2 is replaced with a commercially available RuO2 oxygen evolution catalyst of equal mass, and the other steps are exactly the same as those in Example 6.

[0195] Example 11

[0196] This embodiment provides a method for inhibiting the poisoning of the anode catalyst for PEM electrolyzed water. The method includes the following steps:

[0197] S1. Preparation of the oxygen evolution catalyst:

[0198] Disperse 1 g of TiO2 (particle size of 50 nm) in 120 mL of isopropanol by ultrasonic dispersion, then dropwise add 100 mL of the precursor solution H2IrCl6 with a concentration of 0.0446 M, stir at 60 °C for 2 h. After forming a uniformly dispersed solution, dry it in an oven at 75 °C for 4 h to form a solid mixture (where the mass ratio of Ir to Ti is 1.43:1). Grind the solid mixture and NaNO3 evenly to obtain a ground product (where the mass ratio of Na to Ir is 4.78:1). Calcinate the ground product at 450 °C for 1 h with a heating rate of 10 °C / min, then naturally cool it to room temperature, disperse it in an aqueous solution by ultrasonic wave, and wash it 5 times by centrifugation to remove excessive impurity salts. After drying, grind it evenly to obtain the catalyst TiO2@IrO2 with the required particle size (particle size of 54 nm).

[0199] S2. Phosphoric acid modification:

[0200] Disperse 1 g of the oxygen evolution catalyst TiO2@IrO2 prepared in S1 in 50 mL of n-hexane, add 2 mL of hydrogen peroxide (the content of H2O2 in this hydrogen peroxide is 5 wt%), and stir at 60 °C for 1 h; add 0.25 mL of POCl3, and reflux and stir at 90 °C for 8 h; cool to room temperature, centrifuge to collect the solid precipitate, and wash it several times with n-hexane, ethanol and deionized water, and then dry it at 100 °C for 8 h to obtain the phosphoric acid-modified oxygen evolution catalyst.

[0201] Example 12

[0202] This embodiment provides a method for inhibiting the poisoning of the anode catalyst for PEM electrolyzed water. The method includes the following steps:

[0203] S1. Preparation of the oxygen evolution catalyst:

[0204] 1 g of TiO2 (particle size of 100 nm) was ultrasonically dispersed in 120 mL of isopropanol, and then 10 mL of a precursor solution H2IrCl6 with a concentration of 0.2 M was added dropwise. After stirring at 60 °C for 2 h to form a uniformly dispersed solution, it was dried in an oven at 75 °C for 4 h to form a solid mixture (where the mass ratio of Ir to Ti was 0.64:1). The solid mixture and NaNO3 were ground evenly together to obtain a ground product (where the mass ratio of Na to Ir was 19.14:1). The ground product was calcined at 450 °C for 1 h with a heating rate of 10 °C / min, and then naturally cooled to room temperature. It was ultrasonically dispersed in an aqueous solution and centrifuged and washed with water 5 times to remove excess impurity salts. After drying, it was ground evenly to obtain the catalyst TiO2@IrO2 with the required particle size (particle size of 102 nm).

[0205] S2, Phosphoric acid modification:

[0206] 1 g of the oxygen evolution catalyst TiO2@IrO2 prepared in S1 was dispersed in 50 mL of n-hexane, and 4 mL of hydrogen peroxide (the content of H2O2 in this hydrogen peroxide was 10 wt%) and 0.04 g of the catalyst for Fenton reaction (ferrous chloride) were added. It was stirred at 70 °C for 1.5 h; 0.2 mL of POCl3 was added and refluxed and stirred at 100 °C for 6 h; it was cooled to room temperature, the solid precipitate was collected by centrifugation, and washed several times with n-hexane, ethanol and deionized water, and then dried at 120 °C for 4 h to obtain the phosphoric acid-modified oxygen evolution catalyst.

[0207] Example 13

[0208] This example provides a method for inhibiting the poisoning of the anode catalyst for PEM electrolyzed water, and the method includes the following steps:

[0209] S1, Preparation of the oxygen evolution catalyst:

[0210] 1 g of TiO2 (particle size of 150 nm) was ultrasonically dispersed in 120 mL of isopropanol, and then 20 mL of a precursor solution H2IrCl6 with a concentration of 2 M was added dropwise. After stirring at 60 °C for 2 h to form a uniformly dispersed solution, it was dried in an oven at 75 °C for 4 h to form a solid mixture (where the mass ratio of Ir to Ti was 12.86:1). The solid mixture and NaNO3 were ground evenly together to obtain a ground product (where the mass ratio of Na to Ir was 12.75:1). The ground product was calcined at 450 °C for 1 h with a heating rate of 10 °C / min, and then naturally cooled to room temperature. It was ultrasonically dispersed in an aqueous solution and centrifuged and washed with water 5 times to remove excess impurity salts. After drying, it was ground evenly to obtain the catalyst TiO2@IrO2 with the required particle size (particle size of 158 nm).

[0211] S2, Phosphonic acid modification:

[0212] Disperse 1 g of the oxygen evolution catalyst TiO2@IrO2 prepared from S1 in 50 mL of n-hexane, add 8 mL of hydrogen peroxide (the content of H2O2 in this hydrogen peroxide is 10 wt%) and 0.1 g of the catalyst for Fenton reaction (nickel chloride), and stir at 80 °C for 2 h; add 0.3 mL of phenylphosphonic dichloride PhPOCl2, and reflux and stir at 120 °C for 13 h; cool to room temperature, centrifuge to collect the solid precipitate, and wash it several times with n-hexane, ethanol and deionized water, and then dry it at 80 °C for 12 h to obtain the phosphonic acid modified oxygen evolution catalyst.

[0213] Example 14

[0214] This example provides a method for inhibiting the poisoning of the anode catalyst for PEM electrolyzed water. The difference from Example 11 is only that the preparation of S1 is not carried out, and the oxygen evolution catalyst TiO2@IrO2 in S2 is replaced with an equal mass of commercially available IrO2 oxygen evolution catalyst, and other steps are exactly the same as those in Example 11.

[0215] Example 15

[0216] This example provides a method for inhibiting the poisoning of the anode catalyst for PEM electrolyzed water. The difference from Example 11 is only that the preparation of S1 is not carried out, and the oxygen evolution catalyst TiO2@IrO2 in S2 is replaced with an equal mass of commercially available RuO2 oxygen evolution catalyst, and other steps are exactly the same as those in Example 11.

[0217] Comparative Example 1

[0218] This comparative example provides a preparation method of an oxygen evolution catalyst. The preparation method includes the following steps:

[0219] Disperse 1 g of TiO2 (particle size is 50 nm) in 120 mL of isopropanol by ultrasonic wave, then dropwise add 100 mL of the precursor solution H2IrCl6 with a concentration of 0.0446 M, stir at 60 °C for 2 h, after forming a uniformly dispersed solution, place it in an oven at 75 °C and dry for 4 h to form a solid mixture (where the mass ratio of Ir to Ti is 1.43:1). Grind the solid mixture and NaNO3 evenly to obtain a ground product (where the mass ratio of Na to Ir is 4.78:1). Calcinate the ground product at 450 °C for 1 h with a heating rate of 10 °C / min, and then naturally cool to room temperature, disperse it in an aqueous solution by ultrasonic wave, and wash it 5 times by centrifugation to remove excessive impurity salts, and after drying, grind it evenly to obtain the catalyst TiO2@IrO2 with the required particle size (particle size is 54 nm).

[0220] Comparative Example 2

[0221] This comparative example provides an oxygen evolution catalyst, which is a commercially available IrO₂ oxygen evolution catalyst provided in Example 4, Example 9, and Example 14.

[0222] Comparative Example 3

[0223] This comparative example provides an oxygen evolution catalyst, which is a commercially available RuO₂ oxygen evolution catalyst provided in Example 5, Example 10, and Example 15.

[0224] Comparative Example 4

[0225] This comparative example provides a method for inhibiting the poisoning of the anode catalyst for PEM water electrolysis. The difference from Example 1 is only that no co-modifier is added in S2. Specifically:

[0226] Disperse 1 g of the oxygen evolution catalyst TiO₂@IrO₂ prepared in S1 in 50 mL of methanol, directly add 10 mL of nitric acid (concentration: 0.5 wt%), and reflux and stir at 90 °C for 8 h; after drying at 100 °C for 12 h, wash several times with methanol and deionized water respectively to obtain a sulfate ion-modified oxygen evolution catalyst.

[0227] Comparative Example 5

[0228] This comparative example provides a method for inhibiting the poisoning of the anode catalyst for PEM water electrolysis. The difference from Example 6 is only that no co-modifier is added in S2. Specifically:

[0229] Disperse 1 g of the oxygen evolution catalyst TiO₂@IrO₂ prepared in S1 in 50 mL of deionized water, directly add 0.25 mL of thiourea, and reflux and stir at 90 °C for 8 h; cool to room temperature, then add 5 mL of hydrogen peroxide (the content of H₂O₂ in this hydrogen peroxide is 20 wt%); centrifuge to collect the solid precipitate, wash several times with ethanol and deionized water, and dry at 100 °C for 12 h to obtain a sulfuric acid-modified oxygen evolution catalyst.

[0230] Comparative Example 6

[0231] This comparative example provides a method for inhibiting the poisoning of the anode catalyst for PEM water electrolysis. The difference from Example 11 is only that no co-modifier is added in S2. Specifically:

[0232] Disperse 1 g of the oxygen evolution catalyst TiO₂@IrO₂ prepared in S1 in 50 mL of n-hexane; add 0.25 mL of POCl₃, and reflux and stir at 90 °C for 8 h; cool to room temperature, centrifuge to collect the solid precipitate, wash several times with n-hexane, ethanol and deionized water, and dry at 100 °C for 8 h to obtain a phosphoric acid-modified oxygen evolution catalyst.

[0233] Comparative Example 7

[0234] This comparative example provides a method for suppressing the poisoning of the anode catalyst for PEM electrolyzed water. The difference from Example 1 is only that in S2, heating under reflux is no longer carried out. After adding nitric acid, stirring is carried out at 25 °C for 12 h, and the other steps are exactly the same as those in Example 1.

[0235] Comparative Example 8

[0236] This comparative example provides a method for suppressing the poisoning of the anode catalyst for PEM electrolyzed water. The difference from Example 6 is only that in S2, heating under reflux is no longer carried out. After adding thiourea, stirring is carried out at 25 °C for 12 h, and the other steps are exactly the same as those in Example 6.

[0237] Comparative Example 9

[0238] This comparative example provides a method for suppressing the poisoning of the anode catalyst for PEM electrolyzed water. The difference from Example 6 is only that in S2, heating under reflux is no longer carried out. After adding POCl3, stirring is carried out at 25 °C for 12 h, and the other steps are exactly the same as those in Example 6.

[0239] Application Example 1

[0240] This application example provides a membrane electrode for PEM electrolyzed water, which is prepared by the following steps:

[0241] (1) Deionized water, the anode catalyst for PEM electrolyzed water, an ionomer solution and ethanol are sequentially added into a glass bottle. The glass bottle is placed on a magnetic stirrer. After stirring and dispersing, the solution is transferred to a ball mill jar equipped with ball mill beads, and ball milling is carried out under constant temperature conditions.

[0242] Among them, the anode catalyst is the modified oxygen evolution catalyst provided in Example 1, and the mass of the catalyst accounts for 25 wt% of the total mass of the slurry; the ionomer solution is a perfluorosulfonic acid solution, and the mass of the ionomer solution is 10 wt% of the mass of the catalyst; the alcohol is isopropyl alcohol, and the mass ratio of the added deionized water to ethanol is 5:5; among them, the ball milling conditions are as follows: 3.5 mm ZrO2 ball mill beads, constant temperature ball milling at 20 °C, rotation speed of 650 rpm, and time of 7 h.

[0243] (2) After ball milling and dispersing, the slurry is mixed and defoamed by a defoamer to obtain an anode catalyst layer slurry.

[0244] (3) Coating is carried out on a PTFE membrane by a slot coater (loading 0.5 mg Ir / cm 2 ).

[0245] (4) After drying, it is detected by XRF whether the average loading of iridium element in the catalyst coating meets the standard.

[0246] (5) Subsequently, it is coated on a PTFE membrane with a loading of 0.3 mg Pt / cm2 The cathode catalyst layer and the 115 proton exchange membrane are prepared into a catalyst coated membrane (CCM) by hot pressing and transfer printing.

[0247] Application Examples 2 - 15

[0248] This application example provides a membrane electrode for PEM electrolyzed water. The difference from Application Example 1 is only that the modified oxygen evolution catalyst provided in Example 1 is replaced with an equal amount of the modified oxygen evolution catalyst provided in the corresponding example number. Specifically, Application Example 2 (the modified oxygen evolution catalyst provided in Example 2), Application Example 3 (the modified oxygen evolution catalyst provided in Example 3), and so on, which will not be elaborated one by one, and Application Example 15 (the modified oxygen evolution catalyst provided in Example 15).

[0249] Comparative Application Example 1

[0250] This comparative application example provides a membrane electrode for PEM electrolyzed water. The difference from Application Example 1 is only that the modified oxygen evolution catalyst provided in Example 1 is replaced with the modified oxygen evolution catalyst provided in Comparative Example 1 with an equal loading amount, and other steps are exactly the same as those in Application Example 1.

[0251] Figure 2 It is the atomic force microscope image of the surface ionomer adsorption thickness of the membrane electrode prepared by using the oxygen evolution catalyst modified with the acid radical ions of Example 1 provided for Application Example 1. Figure 3 It is the atomic force microscope image of the surface ionomer adsorption thickness of the membrane electrode prepared by using the unmodified oxygen evolution catalyst of Comparative Example 1 provided for Comparative Application Example 1. From Figure 2 and Figure 3 the comparison, it can be seen that the surface of the catalyst untreated in Comparative Example 1 has a thicker ionomer adsorption layer, which is not conducive to constructing an efficient mass transfer pathway (gas + electron); while in Example 1, a new catalyst / ionomer interface can be constructed through molecular regulation to inhibit excessive adsorption of the ionomer and build an efficient mass transfer channel.

[0252] Comparative Application Examples 2 - 9

[0253] This application example provides a membrane electrode for PEM electrolyzed water. The difference from Application Example 1 is only that the modified oxygen evolution catalyst provided in Example 1 is replaced with an equal amount of the modified oxygen evolution catalyst provided in the corresponding example number. Specifically, Comparative Application Example 2 (the catalyst provided by Comparative Example 2), Comparative Application Example 3 (the catalyst provided by Comparative Example 3), and so on, which will not be elaborated one by one, and Comparative Application Example 9 (the catalyst provided by Example 9).

[0254] Test Example 1

[0255] Multi-channel device performance test

[0256] Test samples: Membrane electrodes for PEM electrolyzed water provided in Application Examples 1 to 15, and membrane electrodes for PEM electrolyzed water provided in Comparative Application Examples 1 to 9.

[0257] Test methods:

[0258] (1) Assembly of the electrolytic cell: Assemble the electrolytic cell in the order of the insulating end plate, the cathode plate, a 0.15-mm gasket, carbon paper, the membrane electrode (CCM), a 2.05-mm gasket, titanium felt, a titanium mesh, and the anode plate. Tighten the electrolytic cell diagonally with a torque wrench (3 N·m), and clamp on the electrode clamp. Pass water under the test conditions of 80°C to conduct an electrochemical performance test, including a polarization performance test and a stability test at a current density of 2 A / cm 2 for the current density.

[0259] (2) Sheet resistance: Test the membrane electrode using a four-probe resistance tester. On average, test 5 - 10 points for each sample and take the average value.

[0260] (3) Electrolyzed water performance curve: Conduct a gradient increase test for the current density from 0.25 A / cm 2 to 6 A / cm 2 . Keep each current point for 2 min and record the corresponding average voltage.

[0261] (4) In-situ impedance: Conduct an in-situ impedance test on the electrolytic cell using an electrochemical impedance tester. The applied constant current is 16 A, the current perturbation is 1 A, and the test frequency ranges from 10,000 Hz to 0.1 Hz.

[0262] The specific test results are shown in Tables 1 to 3 below, and Figure 4 , Figure 5 and Figure 6 as follows:

[0263] Table 1

[0264]

[0265]

[0266] Table 2

[0267]

[0268]

[0269] Table 3

[0270]

[0271]

[0272] As shown in Table 1, the membrane electrode prepared with the surface-modified catalyst has a significantly lower sheet resistance. Specifically, the sheet resistance of the membrane electrode prepared with the surface-modified catalyst can be reduced to below 1.4 KΩ / sq. As shown in Table 2, the surface-modified catalyst has better performance under the PEM water electrolysis conditions, especially in the medium and high current density regions, that is, the resistance control and mass transfer control regions. As shown in Table 3, the surface-modified catalyst has significantly smaller high-frequency resistance and smaller mass transfer impedance. Specifically, the mass transfer impedance of the modified catalyst can be reduced to 0.012 mΩ cm 2 below. It is proved that it has faster electron transfer and gas transport paths due to the inhibition of the over-thick ionomer adsorption on the surface.

[0273] Therefore, after the surface modification of the catalyst of the present invention, during the device application, the high-frequency resistance is reduced by more than 23.8 mΩ cm 2 above, which proves the improvement of its electron conduction ability. At the same time, under the working conditions of a large current density (4.0 A / cm 2 ), the performance is improved by more than 132.7 mV, and the mass transfer impedance is reduced by more than 2.5 mΩ cm 2 above, which proves the construction of an efficient mass transfer channel. The synergy of the two promotes the high-performance expression of the modified catalyst in PEM applications. From the perspective of the actual working conditions, analyzing the reaction sites of the catalyst under the working conditions provides a new perspective for the structural design of the next-generation catalyst. By constructing a new catalyst / ionomer interface at the molecular level, the simple and scalable surface modification strategy has successfully realized the reactivation of the "poisoned" catalyst, improved the catalyst utilization rate, and provided a feasible solution for large-scale low-cost hydrogen production.

[0274] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for inhibiting poisoning of anode catalyst for PEM water electrolysis, characterized in that: The method comprises the following steps: The oxygen evolution catalyst and the co-modifier are mixed and stirred in a solvent to obtain a mixed solution 1; wherein the co-modifier comprises hydrogen peroxide; The mixed solution 1 and the modifier are mixed and refluxed to obtain the mixed solution 2; wherein the modifier comprises any one or a combination of at least two of a reagent containing an acid radical ion, thiourea, a phosphide or a phosphide; The solvent in the second mixed solution is removed to obtain an acid-modified oxygen evolution catalyst.

2. The method for inhibiting poisoning of anode catalyst for PEM water electrolysis according to claim 1, characterized in that: The oxygen evolution catalyst comprises a noble metal-based catalyst; wherein the noble metal-based catalyst comprises an iridium-based catalyst and / or a ruthenium-based catalyst; Preferably, the oxygen evolution catalyst is a composite noble metal catalyst, and the composite noble metal catalyst comprises a noble metal oxide catalyst and a carrier oxide; Preferably, the noble metal oxide catalyst is selected from ruthenium oxide and / or iridium oxide; Preferably, the carrier oxide is selected from titanium oxide; Preferably, the mass ratio of the noble metal oxide catalyst to the carrier oxide is (0.42-9):

1.

3. The method for inhibiting poisoning of anode catalyst for PEM water electrolysis according to claim 2, characterized in that: The composite noble metal catalyst is prepared by the following steps: (a) dispersing a carrier oxide in an alcohol solvent, adding a noble metal precursor solution dropwise, stirring and dispersing, and then drying to obtain a solid mixture; (b) mixing and grinding the solid mixture and a molten metal salt to obtain a grind; (c) calcining, washing, drying and grinding the ground material to obtain the composite noble metal catalyst; Preferably, in step (a), the mass volume ratio of the carrier oxide and the alcohol solvent is 1 g: (100-150) mL; Preferably, in step (a), the alcohol solvent is selected from isopropanol; Preferably, in step (a), the concentration of the noble metal precursor solution is 0.01 to 6 M; Preferably, in step (a), the noble metal precursor solution is selected from a noble metal chlorate solution; wherein the noble metal chlorate solution comprises a chloroiridic acid solution and / or a chlororuthenic acid solution; the solvent of the noble metal precursor solution is selected from any one of water, methanol, ethanol, isopropanol or ethylene glycol, or a combination of at least two thereof; Preferably, in step (a), the stirring and dispersing time is 1 to 3 hours; Preferably, in step (a), the drying temperature is 60 to 90° C., and the drying time is 3 to 5 hours; Preferably, in step (b), the molten metal salt is selected from NaNO3; Preferably, in step (b), the ratio of the mass of the metal element in the molten metal salt to the mass of the noble metal element in the solid mixture is (1.43-19.14):1, preferably (4.78-19.14):1; Preferably, in step (c), the calcination temperature is 350-550° C., the calcination time is 0.5-2 h, and the calcination heating rate is 5-15° C. / min.

4. The method for inhibiting poisoning of anode catalyst for PEM water electrolysis according to claim 1, characterized in that: The mass ratio of the oxygen evolution catalyst to the co-modifier is 1:(0.05-1); Preferably, the mass percentage of the hydrogen peroxide in the solvent is 3 to 30%; Preferably, the co-modifier also includes a catalyst for Fenton reaction; Preferably, the mass percentage of the Fenton reaction catalyst in the solvent is 1 to 20%; Preferably, the Fenton reaction catalyst is selected from any one or a combination of at least two of the chemicals of divalent iron, copper, manganese and nickel; Preferably, in the process of obtaining the mixed solution 1, the temperature of the mixing and stirring is 50 to 80° C., and the time of the mixing and stirring is 0.5 to 3 h.

5. The method for inhibiting poisoning of anode catalyst for PEM water electrolysis according to claim 1, characterized in that: The mass ratio of the oxygen evolution catalyst to the modifier is 1:(0.01-0.1); Preferably, the acid ion-containing reagent is selected from any one of nitric acid, phosphoric acid, sulfuric acid, oxalic acid or lactic acid, or a combination of at least two thereof; Preferably, the phosphide is selected from phosphorus chlorides, preferably phosphorus oxychloride; Preferably, the phosphine compound is selected from phosphine chlorides, preferably phenylphosphonyl dichloride; Preferably, when the modifying agent is a reagent containing acid ions, the solvent is selected from isopropanol; Preferably, when the modifying agent is thiourea, the solvent is selected from water; Preferably, when the modifier is a phosphide and / or a phosphide, the solvent is selected from n-hexane; Preferably, the reflux heating temperature is 80-120° C., and the reflux heating time is 2-14 h.

6. The method for inhibiting poisoning of anode catalyst for PEM water electrolysis according to claim 1, characterized in that: When the modifying agent is a reagent containing acid ions, the method further comprises the following post-treatment steps: The mixed solution 2 is dried at 80-120° C. for 2-24 hours, and then washed to obtain an oxygen evolution catalyst modified with acid radical ions; Preferably, when the modifying agent is thiourea, the method further comprises the following post-treatment steps: The mixed solution 2 and the strong oxidant are mixed at 50-60° C. for 30-180 min, solid precipitates are collected by centrifugation, washed, and dried at 80-120° C. for 2-24 h to obtain a sulfuric acid-modified oxygen evolution catalyst; Preferably, the addition amount of the strong oxidant and the catalyst is (0.1-20):1; Preferably, the strong oxidant is selected from hydrogen peroxide and / or potassium permanganate; Preferably, when the modifier is a phosphide and / or a phosphide, the method further comprises the following post-treatment steps: The mixed solution 2 is centrifuged to collect solid precipitates, washed, and then dried at 80-120° C. for 2-24 hours to obtain an oxygen evolution catalyst modified with phosphoric acid and / or phosphonic acid.

7. A modified oxygen evolution catalyst, characterized in that: The modified oxygen evolution catalyst is prepared by the method for inhibiting poisoning of anode catalyst for PEM water electrolysis according to any one of claims 1 to 6.

8. Use of the modified oxygen evolution catalyst according to claim 7 in preparing a membrane electrode for PEM water electrolysis and / or an electrolytic cell for PEM water electrolysis.

9. A membrane electrode for PEM water electrolysis, characterized in that: The PEM membrane electrode for water electrolysis comprises a proton exchange membrane and an anode catalyst layer and a cathode catalyst layer arranged on both sides of the proton exchange membrane; wherein the anode catalyst layer comprises the modified oxygen evolution catalyst according to claim 7.

10. A PEM electrolytic cell for water electrolysis, characterized in that: The PEM water electrolysis electrolysis cell comprises the PEM water electrolysis membrane electrode according to claim 9.

Images