Proton exchange membrane electrolysis water catalyst slurry and preparation method therefor

Abstract

A proton exchange membrane electrolysis water catalyst slurry, comprising 10-25% of iridium-based catalysts in different valence states, 2-10% of water, 35-65% of an organic alcohol, 15-35% of a perfluorosulfonic acid resin mixed solution and 0.05-0.5% of a surfactant, wherein the iridium-based catalysts in different valence states comprise a iridium-based non-noble metal doped catalyst and a ruthenium-iridium-terbium oxidation state catalyst. By means of a combination of two rhodium-based catalysts in different valence states, the use amount of rhodium used can be reduced, the agglomeration of two rhodium-based catalyst particles in different valence states is also effectively reduced, and the dispersibility of the catalyst, the suspension stability of the slurry and the porosity of a catalytic layer are improved.

Description

A proton exchange membrane water electrolysis catalyst slurry and its preparation method

[0001] Cross-reference information

[0002] This application claims priority to Chinese Patent Application No. 202411537599.2, filed on October 30, 2024, entitled "A Proton Exchange Membrane Electrolysis Water Catalyst Slurry and Its Preparation Method", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to the field of proton exchange membrane electrolysis for hydrogen production technology, and more specifically, to a proton exchange membrane electrolysis catalyst slurry and its preparation method. Background Technology

[0004] Proton exchange membrane (PEM) electrolysis for hydrogen production is one of the effective methods for large-scale hydrogen production in the future. It boasts advantages such as high efficiency, high hydrogen purity, compact electrolyzer and system structure, inherent safety, wide adjustable range of load fluctuations, and suitability for rapid start-up and shutdown. The anode reaction is the rate-controlling step, and the activity, efficiency, and cost of the anode catalyst are currently key factors restricting the large-scale development of PEM electrolysis for hydrogen production. Currently, the main commercial anode catalysts are IrO2 or iridium black elemental catalysts. Ir is scarce and expensive; therefore, the urgent task is to develop efficient methods for preparing membrane electrode slurries that reduce the amount of iridium-based catalyst used, thereby improving the utilization rate of iridium-based catalysts and reducing the amount of iridium catalyst used to lower costs.

[0005] The membrane electrode assembly (MEA), as the core component of PEM water electrolysis, is not only a crucial site for electron generation and separation but also plays a role in water transport and gas expulsion. The MEA mainly consists of a proton exchange membrane, a catalyst layer, and a diffusion layer. The microstructure of the catalyst layer in the MEA is determined by the slurry coated on the proton exchange membrane, and the composition and dispersion of the slurry significantly affect the catalyst active area and the migration rates of protons and electrons. The preparation of the catalyst slurry is critical, as its performance directly affects the catalytic performance of the prepared MEA and ultimately the performance of PEM water electrolysis.

[0006] Commonly used oxygen evolution catalysts include iridium black and iridium dioxide. Metallic iridium is scarce and expensive. The form in which the iridium-based catalyst exists is the main factor affecting the oxygen evolution performance of iridium oxide catalysts. Industrially used iridium-based catalysts can generally be classified into elemental iridium black, IrO₂, and IrO₂. x Catalyst. IrO x Its bulk structure is rich in oxygen vacancies, and its surface contains a large number of hydroxyl groups. In terms of oxygen evolution properties, elemental iridium black is less stable than IrO₂ and IrO. x However, its activity is superior to IrO2 and IrO.x The difference in activity and stability between the two catalysts stems from their different oxygen evolution mechanisms. Lower-cost RuO2 can replace commercial IrO2 as an anode electrode, but under harsh corrosive conditions such as high oxidation potential, low pH, and high oxygen concentration, RuO2 is unstable and eventually decomposes into soluble RuO4 or H2RuO5. Pure iridium black or iridium-based oxidized catalysts struggle to simultaneously achieve both high activity and stability.

[0007] Given the significant application value of iridium-based nanomaterials in PEM water electrolysis technology, there is an urgent need to develop efficient and low-cost methods for preparing iridium-based catalyst membrane electrode slurries in order to promote the large-scale application of PEM water electrolysis technology. Summary of the Invention

[0008] To achieve the above objectives, the present invention aims to provide a proton exchange membrane water electrolysis catalyst slurry and its preparation method. The catalyst slurry uses a combination of two iridium-based catalysts and is formulated with two perfluorosulfonic acid resins and a surfactant, which can reduce the cost of the catalyst while ensuring the suspension stability of the catalyst material.

[0009] To achieve the above objectives, the present invention provides a proton exchange membrane water electrolysis catalyst slurry, wherein, by mass percentage, the proton exchange membrane water electrolysis catalyst slurry comprises 10-25% iridium-based catalyst of different valence states, 2-10% water, 35-65% organic alcohol, 15-35% perfluorosulfonic acid resin mixed solution, and 0.1-1.2% surfactant, and the sum of the mass percentages of each component is 100%.

[0010] The iridium-based catalysts with different valence states include a first iridium-based catalyst and a second iridium-based catalyst, wherein the first iridium-based catalyst is selected from iridium-based non-noble metal doped catalysts, and the second iridium-based catalyst is selected from ruthenium-iridium-terbium oxide catalysts.

[0011] The iridium-based non-noble metal doped catalyst is selected from Ir y Co 1-y and Ir z Ni 1-z One or more combinations of , wherein 0 <y<1、0<z<1;

[0012] The molecular formula of the ruthenium-iridium-terbium oxide catalyst is Tb2Ru. x Ir 2-x O7, where 0 <x<2;

[0013] The perfluorosulfonic acid resin mixed solution contains two or more perfluorosulfonic acid resin solutions with different molar mass values.

[0014] According to a specific embodiment of the present invention, preferably, the proton exchange membrane water electrolysis catalyst slurry comprises, by mass percentage, 15-20% iridium-based catalyst of different valence states, 4-8% water, 45-55% organic alcohol, 20-30% perfluorosulfonic acid resin mixed solution, and 0.2-1% surfactant, wherein the sum of the mass percentages of each component is 100%.

[0015] According to a specific embodiment of the present invention, preferably, in the above-mentioned proton exchange membrane electrolysis water catalyst slurry, the mass ratio of the first iridium-based catalyst and the second iridium-based catalyst is 1:5-1:20, more preferably 1:5-1:15, and even more preferably 1:6-1:12.

[0016] According to a specific embodiment of the present invention, preferably, in the above-mentioned proton exchange membrane water electrolysis catalyst slurry, the iridium-based catalyst with different valence states is Ir. y Co 1-y Ir z Ni 1-z Tb2Ru x Ir 2-x The combination of O7, O7, and O7 has a mass ratio of 1:1:8.

[0017] According to a specific embodiment of the present invention, the ruthenium-iridium-terbium oxidized catalyst used in the above-mentioned proton exchange membrane water electrolysis catalyst slurry has an A2B2O7 structure, i.e., a pyrochlore structure, and belongs to the doped ruthenium-iridium-terbium oxidized catalyst. Preferably, in the molecular formula of the ruthenium-iridium-terbium oxidized catalyst, 0.05≤x≤1.95; more preferably, 0.4≤x≤1.6. The catalyst used in the present invention is ruthenium-based pyrochlore, a mixed metal oxide. Compared with rutile-type RuO2 and perovskite-type ruthenium-based oxides, it has a more stable band structure, exhibits higher oxygen evolution reaction (OER) activity and stability under harsh working environments of high voltage and strong acidity, and can significantly reduce the content of the noble metal Ru, thereby reducing the cost of the membrane electrode and improving the conductivity and mass-to-weight ratio of the membrane electrode.

[0018] According to a specific embodiment of the present invention, preferably, the ruthenium-iridium-terbium oxidation state catalyst is Tb₂Ru. 1.95 Ir 0.05 O7、Tb2Ru 1.90 Ir 0.10 O7、Tb2Ru 1.85 Ir 0.15 O7、Tb2Ru 1.80 Ir 0.20 O7、Tb2Ru 1.75 Ir 0.25 O7、Tb2Ru 1.70 Ir 0.30 O7、Tb2Ru1.65 There is 0.35 O7、Tb2Ru 1.60 There is 0.40 O7、Tb2Ru 1.55 There is 0.45 O7、Tb2Ru 1.50 There is 0.50 O7、Tb2Ru 1.45 There is 0.55 O7、Tb2Ru 1.40 There is 0.60 O7、Tb2Ru 1.35 There is 0.65 O7、Tb2Ru 1.30 There is 0.70 O7、Tb2Ru 1.25 There is 0.75 O7、Tb2Ru 1.20 There is 0.80 O7、Tb2Ru 1.15 There is 0.85 O7、Tb2Ru 1.10 There is 0.90 O7、Tb2Ru 1.05 There is 0.95 O7、Tb2Ru 1.00 There is 1.00 O7、Tb2Ru 0.95 There is 1.05 O7、Tb2Ru 0.90 There is 1.10 O7、Tb2Ru 0.85 There is 1.15 O7、Tb2Ru 0.80 There is 1.20 O7、Tb2Ru 0.75 There is 1.25 O7、Tb2Ru 0.70 There is 1.30 O7、Tb2Ru 0.65 There is 1.35 O7、Tb2Ru 0.60 There is 1.40 O7、Tb2Ru 0.55 There is 1.45 O7、Tb2Ru 0.50 There is 1.50 O7、Tb2Ru 0.45 There is 1.55 O7、Tb2Ru 0.40 There is 1.60 O7、Tb2Ru 0.35 There is 1.65 O7、Tb2Ru 0.30 There is 1.70O7、Tb2Ru 0.25 Ir 1.75 O7、Tb2Ru 0.20 Ir 1.80 O7、Tb2Ru 0.15 Ir 1.85 O7、Tb2Ru 0.10 Ir 1.90 O7、Tb2Ru 0.05 Ir 1.95 At least one of O7.

[0019] According to a specific embodiment of the present invention, preferably, the ruthenium-iridium-terbium oxide catalyst is selected from Tb₂Ru. 1.6 Ir 0.4 O7、Tb2Ru 1.0 Ir 1.0 O7、Tb2Ru 0.4 Ir 1.6 One or more combinations of O7.

[0020] According to a specific embodiment of the present invention, preferably, the ruthenium-iridium-terbium catalyst is particulate with a particle size of 40-180 nm, more preferably, with a particle size of 60-80 nm. The ruthenium-iridium-terbium oxide catalyst is a nanocatalyst; controlling its particle size within the above range allows for a higher specific surface area and exhibits better oxygen evolution reaction (OER) catalytic activity.

[0021] According to a specific embodiment of the present invention, the preparation method of the above-mentioned ruthenium-iridium-terbium catalyst includes the following steps:

[0022] (1) Provide a mixed solution containing ruthenium ions, terbium ions and iridium ions;

[0023] (2) Add water-soluble organic matter as a metal ion complex to the mixed solution and dry it to obtain a gel precursor;

[0024] (3) The gel precursor is pulverized and calcined in an oxygen-containing atmosphere to obtain a ruthenium-iridium-terbium catalyst.

[0025] According to a specific embodiment of the present invention, preferably, in the above preparation method, in the mixed solution of step (1), the molar ratio of ruthenium ions, terbium ions and iridium ions is the same as that of the Tb2Ru x Ir 2-x The molar ratios of Ru, Tb, and Ir in O7 are the same. In step (1), deionized water can be used as the solvent for the mixed solution.

[0026] According to a specific embodiment of the present invention, preferably, in the above preparation method, the concentration of ruthenium ions in the mixed solution is 0.001-0.1 mol / L, the concentration of terbium ions is 0.001-0.1 mol / L, and the concentration of iridium ions is 0.001-0.1 mol / L, based on the volume of the mixed solution. More preferably, the concentration of ruthenium ions in the mixed solution is 0.01-0.05 mol / L, the concentration of terbium ions is 0.01-0.05 mol / L, and the concentration of iridium ions is 0.005-0.02 mol / L.

[0027] According to a specific embodiment of the present invention, preferably, in the above preparation method, the water-soluble organic compound is selected from one or a combination of two or more of citric acid, glycine, malic acid, and ethylenediaminetetraacetic acid. In the preparation of the gel precursor of the present invention, only one water-soluble organic compound is needed as a metal ion complex, without the need to add alcohols.

[0028] According to a specific embodiment of the present invention, preferably, in the above preparation method, the molar ratio of the water-soluble organic matter to the metal ions (i.e., the sum of ruthenium ions, terbium ions, and iridium ions) is 1:1 to 1:4.

[0029] According to a specific embodiment of the present invention, preferably, in the above preparation method, the drying temperature is 70-90°C, more preferably 80°C. In the process of preparing the gel precursor, the various raw materials only need to be mixed in water and dried at a low temperature, without the need for a long heating reaction process. Therefore, this process of the present invention is relatively simple and low in cost.

[0030] According to a specific embodiment of the present invention, preferably, in the above preparation method, the calcination temperature is 700-1100℃ and the holding time is 1-12 hours.

[0031] According to a specific embodiment of the present invention, preferably, in the above preparation method, the ruthenium ions are provided by one or a combination of two or more of ruthenium nitrate, ruthenium acetate, and ruthenium trichloride.

[0032] According to a specific embodiment of the present invention, preferably, in the above preparation method, the terbium ions are provided by terbium chloride, and the iridium ions are provided by iridium chloride and / or iridium tetrachloride.

[0033] In the ruthenium-iridium-terbium catalyst used in this invention, the terbium ion has a unique outermost 4f electron configuration (4f... 8 Half-filled or fully-filled orbitals are relatively stable and difficult to lose further electrons, while terbium ions, which can reach a half-filled state by losing just one electron, easily transition to an electron-deficient state (4f). 7Due to the Tb-O-Ru double exchange in pyrochlore, more electrons can be induced from ruthenium ions to terbium ions, thereby inducing more highly active pentavalent ruthenium sites. Furthermore, the ruthenium-iridium-terbium catalyst used in this invention employs Ir... 4+ Replace some of the Ru in the pyrochlore-structured Tb2Ru2O7 4+ Compared to Tb₂Ru₂O₇, the ruthenium-iridium-terbium catalyst of this invention forms a [IrO₆]-[RuO₆] network structure. Electrons at ruthenium sites can be transferred to iridium sites via oxygen. This double exchange interaction constructs a spin-polarized charge transport channel, optimizes the spin distribution of d-orbital electrons in Ru and Ir, shortens the Ru-O bond length, effectively weakens the octahedral distortion caused by the Jameer-Taylor effect, and achieves the construction of a stable [IrO₆]-[RuO₆] framework. This alleviates the Jameer-Taylor distortion of the [RuO₆] unit in pyrochlore, thereby making the active sites of the ruthenium-iridium-terbium catalyst more stable in the OER process, obtaining a more ideal octahedral stable framework structure, improving the intrinsic activity and stability of the catalyst, and thus promoting the oxygen evolution reaction.

[0034] According to a specific embodiment of the present invention, preferably, the organic alcohol is selected from one or more combinations of ethylene glycol, glycerol, ethanol, n-propanol, and isopropanol, more preferably isopropanol and / or ethanol.

[0035] According to a specific embodiment of the present invention, preferably, the surfactant is selected from at least one of anionic surfactants. The anionic surfactant is preferably a small-molecule or high-molecular-weight anionic surfactant having a hydrophilic group, more preferably selected from one or more combinations of (perfluoro)alkyl or arylsulfonic acids, (perfluoro)alkyl or arylsulfonic acids, (perfluoro)alkyl or arylcarboxylic acids, and (perfluoro)alkyl or arylphosphoric acids, such as perfluoroalkylcarboxylic acids, specifically perfluorododecanecarboxylic acid, etc.

[0036] According to a specific embodiment of the present invention, preferably, the perfluorosulfonic acid resin mixed solution comprises resin solution a and resin solution b, wherein the molar mass of resin solution a is 600-900, and the molar mass of resin solution b is 900-1200. More preferably, the molar mass of resin solution a is 700, and the molar mass of resin solution b is 1000. Under stirring conditions, the perfluorosulfonic acid resin mixed solution can effectively encapsulate the catalyst particles, which is beneficial to the formation of suspension.

[0037] According to a specific embodiment of the present invention, preferably, the concentration of the perfluorosulfonic acid resin mixed solution is 5%-20%.

[0038] According to a specific embodiment of the present invention, preferably, the mass ratio of resin solution a to resin solution b is 1:1 to 1:10, the concentration of resin solution a is 5% to 20%, and the concentration of resin solution b is 5% to 20%.

[0039] The present invention also provides a method for preparing the above-mentioned proton exchange membrane water electrolysis catalyst slurry, which includes the following steps:

[0040] An iridium-based non-precious metal doped catalyst, a ruthenium-iridium-terbium oxidized catalyst, and water and a surfactant were mixed, and then a perfluorosulfonic acid resin mixture and an organic alcohol were added sequentially to obtain a mixed solution.

[0041] The mixed solution was subjected to ultrasonic vibration and ball milling to obtain the proton exchange membrane water electrolysis catalyst slurry.

[0042] According to a specific embodiment of the present invention, preferably, in the above-mentioned slurry preparation method, by fully mixing the catalyst with water and surfactant, the catalyst can be fully wetted, thereby preventing catalyst agglomeration and sedimentation and improving the dispersibility of the slurry.

[0043] According to a specific embodiment of the present invention, preferably, in the above-mentioned method for preparing slurry, the ultrasonic vibration time is 10-30 minutes and the ultrasonic power is 350-750W; more preferably, the ultrasonic vibration time is 20 minutes and the ultrasonic power is 500W.

[0044] According to a specific embodiment of the present invention, preferably, in the above-mentioned method for preparing slurry, the ball milling time is 30-120 minutes and the rotation speed is 300-500 rpm; more preferably, the ball milling time is 60 minutes and the rotation speed is 400 rpm.

[0045] The biggest challenge in preparing membrane electrode catalyst slurries is their dispersibility and suspension stability. For example, using both iridium-based non-precious metal doped catalysts and doped iridium-based oxidized catalysts simultaneously results in poor suspension stability. Compared to conventional PEM water electrolysis anode slurry preparation techniques, the proton exchange membrane water electrolysis anode catalyst slurry and its preparation method provided in this invention effectively reduce catalyst particle agglomeration and improve catalyst dispersibility, slurry suspension stability, and catalyst layer porosity by introducing a mixed solution of two perfluorosulfonic acid resins and a surfactant. Furthermore, different types of perfluorosulfonic acid resins used in the catalyst slurry preparation result in different catalytic characteristics of the membrane electrode. Besides the type of resin, the ratio and form of other components in the slurry also significantly affect the catalytic performance of the membrane electrode. Therefore, the catalyst slurry preparation method is crucial for improving its catalytic performance.

[0046] Simple iridium-based non-precious metal doped catalysts or iridium-based oxidized catalysts are difficult to simultaneously achieve both activity and stability. This invention introduces two iridium-based catalysts with different valence states. Through the synergistic effect of at least two iridium-based catalysts with different valence states, the activity and stability of iridium-based catalysts with different valence states can be balanced, improving the utilization rate of iridium-based catalysts and increasing the mass-specific activity of the membrane electrode. Moreover, the introduced doped ruthenium-iridium-terbium oxidized catalyst can effectively reduce the amount of iridium used, thereby reducing the cost of the membrane electrode.

[0047] Compared to conventional techniques for preparing PEM (Polymer Electrolytic Metal) anode slurries, this invention employs a combination of doped ruthenium-iridium-terbium nano-oxidized catalysts and iridium-based non-precious metal doped alloy catalysts, reducing the amount of iridium used and thus lowering the cost of the membrane electrode. Simultaneously, it balances the activity and stability of the two different iridium-based catalyst states (the combination of iridium-based non-precious metal doped alloy catalysts and doped ruthenium-iridium-terbium oxidized catalysts), improving the specific activity of the membrane electrode. This invention also effectively reduces the agglomeration of the two different iridium-based catalyst particles, improving catalyst dispersibility, slurry suspension stability, and catalyst layer porosity. Attached Figure Description

[0048] Figure 1 shows the XRD diffraction patterns of the ruthenium-iridium-terbium catalysts prepared in Examples 1-3 and the Tb2Ru2O7 and Tb2Ir2O7 prepared in Comparative Examples 1-2.

[0049] Figure 2 shows the SEM images of the ruthenium-iridium-terbium catalysts prepared in Preparation Examples 1-3 and the Tb2Ru2O7 and Tb2Ir2O7 prepared in Comparative Examples 1-2.

[0050] Figure 3 shows the particle size distribution statistics of the ruthenium-iridium-terbium catalysts prepared in Preparation Examples 1-3 and the Tb2Ru2O7 and Tb2Ir2O7 prepared in Comparative Examples 1-2.

[0051] Figure 4 shows the polarization curves of the ruthenium-iridium-terbium catalysts prepared in Examples 1-3 and the catalysts prepared in Comparative Examples 1-4 in 0.5 M sulfuric acid solution.

[0052] Figure 5 shows the ruthenium-iridium-terbium catalysts prepared in Examples 1-3 and the catalysts prepared in Comparative Examples 1-4 in 0.5 M sulfuric acid solution and at 10 mA / cm². 2 Chronopotential curves at current density. Detailed Implementation

[0053] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0054] The Ir used in the examples and comparative examples 0.8 Co0.2 The alloy catalyst is prepared in the following manner:

[0055] Weigh 10 mg of iridium trichloride, 2.2 mg of cobalt acetylacetonate, and 100 mg of citric acid into a 50 ml flask, add 20 ml of benzyl alcohol, and sonicate for about 1 hour to obtain a mixture.

[0056] The mixture was transferred to a high-pressure reactor, placed in a rotary oven, and reacted at 120°C for 3 hours. After the reaction cooled naturally to room temperature, IrCo alloy nanoclusters were obtained, i.e., Ir... 0.8 Co 0.2 Alloy catalyst; the obtained product was washed three times with ethanol and dried for later use.

[0057] The Ir used in the examples and comparative examples 0.8 Ni 0.2 The alloy catalyst is prepared in the following manner:

[0058] Weigh 10 mg of iridium trichloride, 2.2 mg of nickel acetylacetonate, and 80 g of polyvinylpyrrolidone into a 50 ml flask, add 20 ml of benzyl alcohol, and sonicate for about 1 hour to obtain a mixture.

[0059] The mixture was transferred to a high-pressure reactor, placed in a rotary oven, and reacted at 100°C for 3 hours. After the reaction cooled naturally to room temperature, IrNi alloy nanoclusters were obtained, i.e., IrNi alloy nanoclusters. 0.8 Ni 0.2 Alloy catalyst; the obtained product was washed three times with ethanol and dried for later use.

[0060] Preparation Example 1:

[0061] This preparation example provides a ruthenium-iridium-terbium catalyst (doped ruthenium-iridium-terbium oxidized catalyst), the molecular formula of which is Tb₂Ru. 1.6 Ir 0.4 O7 has a pyrochlore structure and a particle size between 40-180 nm.

[0062] This preparation example also provides a method for preparing the above-mentioned ruthenium-iridium-terbium catalyst, the specific steps of which are as follows:

[0063] (1) Dissolve 0.84g of citric acid in 20mL of deionized water, add 0.173g of terbium chloride, 0.083g of ruthenium nitrate and 0.015g of iridium chloride, and sonicate to dissolve evenly to obtain a mixed solution;

[0064] (2) The above mixed solution was placed in an oven at 80°C and dried and aged to obtain a fluffy dry gel. The dry gel was ball-milled to obtain gel powder.

[0065] (3) The above gel powder was heated in a muffle furnace at 1000℃ for 4 hours to obtain the powder product Tb2Ru. 1.6 Ir 0.4 O7.

[0066] Preparation Example 2:

[0067] This preparation example provides a ruthenium-iridium-terbium catalyst with the molecular formula Tb₂Ru. 1.0 Ir 1.0 O7 has a pyrochlore structure and a particle size between 40-160 nm.

[0068] This preparation example also provides a method for preparing the above-mentioned ruthenium-iridium-terbium catalyst, the specific steps of which are as follows:

[0069] (1) Dissolve 0.48g glycine in 20mL deionized water, add 0.055g iridium tetrachloride, 0.073g ruthenium acetate and 0.173g terbium chloride, and sonicate to dissolve evenly to obtain a mixed solution;

[0070] (2) The above mixed solution was placed in an oven at 80°C and dried and aged to obtain a fluffy dry gel. The dry gel was ball-milled to obtain gel powder.

[0071] (3) The above gel powder was heated in a muffle furnace at 1000℃ for 4 hours to obtain the powder product Tb2Ru. 1.0 Ir 1.0 O7.

[0072] Preparation Example 3:

[0073] This preparation example provides a ruthenium-iridium-terbium catalyst with the molecular formula Tb₂Ru. 0.4 Ir 1.6 O7 has a pyrochlore structure and a particle size between 40-140 nm.

[0074] This preparation example also provides a method for preparing the above-mentioned ruthenium-iridium-terbium catalyst, the specific steps of which are as follows:

[0075] (1) Dissolve 0.48g glycine in 20mL deionized water, add 0.088g iridium tetrachloride, 0.041g ruthenium trichloride and 0.173g terbium chloride, and sonicate to dissolve evenly to obtain a mixed solution;

[0076] (2) The above mixed solution was placed in an oven at 80°C and dried and aged to obtain a fluffy dry gel. The dry gel was ball-milled to obtain gel powder.

[0077] (3) The above gel powder was heated in a muffle furnace at 1000℃ for 4 hours to obtain the powder product Tb2Ru. 0.4 Ir 1.6O7.

[0078] Preparation of Comparative Example 1

[0079] This comparative example provides a Tb2Ru2O7 catalyst with a pyrochlore structure and a particle size between 40-180 nm.

[0080] This comparative example also provides a method for preparing the above-mentioned Tb2Ru2O7 catalyst, the specific steps of which are as follows:

[0081] (1) Dissolve 0.84g of citric acid in 20mL of deionized water, add 0.103g of ruthenium trichloride and 0.173g of terbium chloride, and sonicate to dissolve evenly to obtain a mixed solution;

[0082] (2) The above mixed solution was placed in an oven at 80°C and dried and aged to obtain a fluffy dry gel. The dry gel was ball-milled to obtain gel powder.

[0083] (3) The above gel powder was heated in a muffle furnace at 1100℃ for 2 hours to obtain the powder product Tb2Ru2O7.

[0084] Preparation of Comparative Example 2

[0085] This comparative example provides a Tb₂Ir₂O₇ catalyst and its preparation method. The Tb₂Ir₂O₇ catalyst has a pyrochlore structure and a particle size between 40-140 nm.

[0086] This comparative example also provides a method for preparing the above-mentioned Tb₂Ir₂O₇ catalyst, the specific steps of which are as follows:

[0087] (1) Dissolve 0.84g of citric acid in 20mL of deionized water, add 0.11g of iridium tetrachloride and 0.173g of terbium chloride, and sonicate to dissolve evenly to obtain a mixed solution;

[0088] (2) The above mixed solution was placed in an oven at 80°C and dried and aged to obtain a fluffy dry gel. The dry gel was ball-milled to obtain gel powder.

[0089] (3) The above gel powder was heated in a muffle furnace at 1100℃ for 6 hours to obtain the powder product Tb2Ir2O7.

[0090] Preparation of Comparative Example 3

[0091] A commercially available anhydrous iridium oxide catalyst, the anhydrous iridium oxide having the molecular formula IrO2, was purchased from Alfaesa (China) Chemical Co., Ltd., CAS No. 12030-49-8, with a purity of 99.99%.

[0092] Preparation of Comparative Example 4

[0093] A commercially available anhydrous ruthenium oxide catalyst, the anhydrous ruthenium oxide having the molecular formula RuO2, was purchased from Alfaesa (China) Chemical Co., Ltd., CAS No. 12036-10-1, with a purity of 99.95%.

[0094] (1) XRD characterization

[0095] X-ray powder diffraction was performed on the catalyst materials prepared in Examples 1-3 and Comparative Examples 1-2, and the results are shown in Figure 1. As can be seen from Figure 1, the Ir-substituted Ru ruthenium-iridium-terbium catalysts of Examples 1-3 and the undoped Tb₂Ru₂O₇ and Tb₂Ir₂O₇ catalysts of Comparative Examples 1-2 have similar characteristic peaks. However, the diffraction peaks of the prepared examples are slightly shifted to lower angles, indicating that iridium doping causes a slight lattice expansion.

[0096] (2) SEM characterization

[0097] The catalysts prepared in Examples 1-3 and Comparative Examples 1-2 were subjected to scanning electron microscopy (SEM) analysis, as shown in Figure 2. Figure 2 shows that the Ir-substituted Ru ruthenium-iridium-terbium catalysts of Examples 1-3, the undoped Tb₂Ru₂O₇ catalysts of Comparative Examples 1-2, and the Tb₂Ir₂O₇ catalysts have similar particle sizes, mostly between 40-180 nm. Figure 3 shows the particle size distribution of the ruthenium-iridium-terbium catalysts prepared in Examples 1-3 and the catalysts prepared in Comparative Examples 1-2. Figure 3 indicates that the particle size of the catalysts in Examples 1-3 tends to decrease after Ir doping, suggesting that doping refines the grain size.

[0098] (3) Electrochemical testing

[0099] Three-electrode testing is performed in an acidic solution, following these steps:

[0100] Take 4 mg of each of the catalyst materials obtained in Preparation Examples 1-3 and Preparation Comparative Examples 1-4, mix them with 1 mg of acetylene black, dissolve them in 0.5 mL of ethanol, and ultrasonically disperse them for 30 min respectively.

[0101] Add 20 μL of 5 wt% Nafion solution to each electrode and continue dispersing for 30 min. Take 5 μL and coat it onto a glassy carbon electrode with a diameter of 4 mm. Let it air dry to obtain the electrode.

[0102] Using the aforementioned electrode as the working electrode, the standard hydrogen electrode as the reference electrode, and the shape-stable anode as the counter electrode (shape-stable anode refers to the coated titanium anode, commonly known as the size-stable anode, abbreviated as DSA), a three-electrode electrochemical system was formed, and its electrochemical performance was tested in 0.5M H2SO4 solution. The voltage scan range of the polarization curve was 1.1–1.6 V, and the scan rate was 10 mV / s. The results are shown in Figure 4, and the overpotential results are shown in Table 1.

[0103] The working electrode is at 10 mA / cm 2 The current density was continuously operated in a three-electrode electrolytic cell, and the voltage change curve over time was recorded. The results are shown in Figure 5.

[0104] Table 1

[0105] As can be seen from the overpotential data shown in Table 1, the catalysts provided in the preparation examples have high oxygen evolution activity. The oxygen evolution reaction catalytic activity of the commercial catalysts in preparation examples 1-3 and preparation example 1 is superior to that of preparation example 3-4, proving that the catalysts and their preparation methods provided in the preparation examples are advanced.

[0106] As can be seen from Figure 4 and Table 1, at a potential of 1.5V relative to the standard hydrogen electrode potential, the electrode current density corresponding to Preparation Example 1 is higher than that corresponding to Preparation Comparative Examples 1-2, and is much higher than that of Preparation Comparative Examples 3-4.

[0107] As can be seen from Figure 5 and Table 1, during the constant current electrolysis process of more than 30 hours, the electrode voltage of the catalyst of Preparation Example 1 did not change significantly, while the electrode made of Tb2Ru2O7 of Comparative Example 1 showed a significant performance degradation after 10 hours of electrolysis. This indicates that the ruthenium-iridium-terbium catalyst provided by the preparation examples can significantly improve the intrinsic stability in the acidic oxygen evolution reaction.

[0108] Example 1

[0109] This embodiment provides a proton exchange membrane water electrolysis catalyst slurry S1, and the preparation steps are as follows:

[0110] (1) Weigh 0.2g Ir 0.8 Co 0.2 Catalyst, 1.8g Tb2Ru 1.6 Ir 0.4For the O7 catalyst, 0.6 g of water and 0.01 g of perfluorododecylcarboxylic acid were slowly added to ensure thorough mixing and wetting of the catalyst. Then, 3 g of a perfluorosulfonic acid resin solution mixture, 4.5 g of isopropanol, and 1 g of ethanol were added sequentially. The perfluorosulfonic acid resin solution mixture contained resin solution a (molar mass value of 700, concentration of 20 wt%) and resin solution b (molar mass value of 1000, concentration of 20 wt%), with a mass ratio of 1:9, i.e., 0.3 g of resin solution a and 2.7 g of resin solution b were added to obtain the mixed solution.

[0111] (2) The mixed solution is ultrasonically vibrated (ultrasonic power of 500W) for 20 minutes to make it uniformly mixed, and then ball milled for 60 minutes (speed of 400rpm) to obtain catalyst slurry S1.

[0112] Example 2

[0113] This embodiment provides a proton exchange membrane water electrolysis catalyst slurry S2, and the preparation steps are as follows:

[0114] (1) Weigh 0.2g Ir 0.8 Ni 0.2 Catalyst, 1.8g Tb2Ru 1.6 Ir 0.4 For the O7 catalyst, 0.6 g of water and 0.01 g of perfluorododecylcarboxylic acid were slowly added to ensure thorough mixing and wetting of the catalyst. Then, 3 g of a perfluorosulfonic acid resin solution mixture, 4.5 g of isopropanol, and 1 g of ethanol were added sequentially. The perfluorosulfonic acid resin solution mixture contained resin solution a (molar mass value of 700, concentration of 20 wt%) and resin solution b (molar mass value of 1000, concentration of 20 wt%), with a mass ratio of 1:9, i.e., 0.3 g of resin solution a and 2.7 g of resin solution b were added to obtain the mixed solution.

[0115] (2) The mixed solution is ultrasonically vibrated (ultrasonic power of 500W) for 20 minutes to make it uniformly mixed; then it is ball-milled for 60 minutes (speed of 400rpm) to obtain catalyst slurry S2.

[0116] Example 3

[0117] This embodiment provides a proton exchange membrane water electrolysis catalyst slurry S3, and the preparation steps are as follows:

[0118] (1) Weigh 0.1g Ir 0.8 Co 0.2 Catalyst, 0.1g Ir 0.8 Ni 0.2 Catalyst, 1.8g Tb2Ru 1.6 Ir 0.4For the O7 catalyst, 0.6 g of water and 0.01 g of perfluorododecylcarboxylic acid were slowly added to ensure thorough mixing and wetting of the catalyst. Then, 3 g of a perfluorosulfonic acid resin solution mixture, 4.5 g of isopropanol, and 1 g of ethanol were added sequentially. The perfluorosulfonic acid resin solution mixture contained resin solution a (molar mass value of 700, concentration of 20 wt%) and resin solution b (molar mass value of 1000, concentration of 20 wt%), with a mass ratio of 1:9, i.e., 0.3 g of resin solution a and 2.7 g of resin solution b were added to obtain the mixed solution.

[0119] (2) The mixed solution is ultrasonically vibrated (ultrasonic power of 500W) for 20 minutes to make it uniformly mixed; then it is ball-milled for 60 minutes (speed of 400rpm) to obtain catalyst slurry S3.

[0120] Example 4

[0121] This embodiment provides a proton exchange membrane water electrolysis catalyst slurry S4, and the preparation steps are as follows:

[0122] (1) Weigh 0.1g Ir 0.8 Ni 0.2 Catalyst, 0.1g Ir 0.8 Co 0.2 Catalyst, 1.8g Tb2Ru 1.6 Ir 0.4 For the O7 catalyst, 0.6 g of water and 0.01 g of perfluorododecylcarboxylic acid were slowly added to ensure thorough mixing and wetting of the catalyst. Then, 3 g of a perfluorosulfonic acid resin solution mixture, 4.5 g of isopropanol, and 1 g of ethanol were added sequentially. The perfluorosulfonic acid resin solution mixture contained resin solution a (molar mass value of 700, concentration of 20 wt%) and resin solution b (molar mass value of 1000, concentration of 20 wt%), with a mass ratio of 1:1, i.e., 1.5 g of resin solution a and 1.5 g of resin solution b were added to obtain the mixed solution.

[0123] (2) The mixed solution is ultrasonically vibrated (ultrasonic power of 500W) for 20 minutes to make it uniformly mixed; then it is ball-milled for 60 minutes (speed of 400rpm) to obtain catalyst slurry S4.

[0124] Comparative Example 1

[0125] This comparative example provides a proton exchange membrane water electrolysis catalyst slurry C1, and the preparation steps are as follows:

[0126] (1) Weigh 2g of Tb2Ru 1.6 Ir 0.4For the O7 catalyst, 0.6 g of water and 0.01 g of perfluorododecylcarboxylic acid were slowly added to ensure thorough mixing and wetting of the catalyst. Then, 3 g of a perfluorosulfonic acid resin solution mixture, 4.5 g of isopropanol, and 1 g of ethanol were added sequentially. The perfluorosulfonic acid resin solution mixture contained resin solution a (molar mass value of 700, concentration of 20 wt%) and resin solution b (molar mass value of 1000, concentration of 20 wt%), with a mass ratio of 1:9, i.e., 0.3 g of resin solution a and 2.7 g of resin solution b were added to obtain the mixed solution.

[0127] (2) The mixed solution is ultrasonically vibrated (ultrasonic power of 500W) for 20 minutes to make it uniformly mixed; then it is ball-milled for 60 minutes (speed of 400rpm) to obtain catalyst slurry C1.

[0128] Comparative Example 2

[0129] This comparative example provides a proton exchange membrane water electrolysis catalyst slurry C2, and the preparation steps are as follows:

[0130] (1) Weigh 0.02g Ir 0.8 Co 0.2 Catalyst, 1.98g Tb2Ru 1.6 Ir 0.4 For the O7 catalyst, 0.6 g of water and 0.01 g of perfluorododecylcarboxylic acid were slowly added to ensure thorough mixing and wetting of the catalyst. Then, 3 g of a perfluorosulfonic acid resin solution mixture, 4.5 g of isopropanol, and 1 g of ethanol were added sequentially. The perfluorosulfonic acid resin solution mixture contained resin solution a (molar mass value of 700, concentration of 20 wt%) and resin solution b (molar mass value of 1000, concentration of 20 wt%), with a mass ratio of 1:9, i.e., 0.3 g of resin solution a and 2.7 g of resin solution b were added to obtain the mixed solution.

[0131] (2) The mixed solution is ultrasonically vibrated (ultrasonic power of 500W) for 20 minutes to make it uniformly mixed; then it is ball-milled for 60 minutes (speed of 400rpm) to obtain catalyst slurry C2.

[0132] Comparative Example 3

[0133] This comparative example provides a proton exchange membrane water electrolysis catalyst slurry C3, and the preparation steps are as follows:

[0134] (1) Weigh 0.02g Ir 0.8 Ni 0.2 Catalyst, 1.98g Tb2Ru 1.6 Ir 0.4For the O7 catalyst, 0.6g of water and 0.01g of perfluorododecylcarboxylic acid were slowly added to thoroughly mix and wet the catalyst. Then, 3g of a perfluorosulfonic acid resin solution mixture, 4.5g of isopropanol, and 1g of ethanol were added sequentially. The perfluorosulfonic acid resin solution mixture contained resin solution a (molar mass value of 700, concentration of 20wt%) and resin solution b (molar mass value of 1000, concentration of 20wt%), with a mass ratio of 1:9, i.e., 0.3g of resin solution a and 2.7g of resin solution b were added to obtain the mixed solution.

[0135] (2) The mixed solution is ultrasonically vibrated (ultrasonic power of 500W) for 20 minutes to make it uniformly mixed; then it is ball-milled for 60 minutes (speed of 400rpm) to obtain catalyst slurry C3.

[0136] Comparative Example 4

[0137] This comparative example provides a proton exchange membrane water electrolysis catalyst slurry C4, and the preparation steps are as follows:

[0138] (1) Weigh 0.1g Ir 0.8 Co 0.2 Catalyst, 0.1g Ir 0.8 Ni 0.2 Catalyst, 1.8g Tb2Ru 1.6 Ir 0.4 For the O7 catalyst, 0.6 g of water and 0.01 g of perfluorododecylcarboxylic acid were slowly added to it to fully mix and wet the catalyst; then 3 g of perfluorosulfonic acid resin solution a (molar mass value of 700, concentration of 20 wt%), 4.5 g of isopropanol and 1 g of ethanol were added in sequence to obtain a mixed solution.

[0139] (2) The mixed solution was ultrasonically vibrated (ultrasonic power of 500W) for 20 minutes to make it uniform. Then it was ball-milled for 60 minutes (speed of 400rpm) to obtain catalyst slurry C4.

[0140] Comparative Example 5

[0141] This comparative example provides a proton exchange membrane water electrolysis catalyst slurry C5, and the preparation steps are as follows:

[0142] (1) Weigh 0.1g Ir 0.8 Co 0.2 Catalyst, 0.1g Ir 0.8 Ni 0.2 Catalyst, 1.8g Tb2Ru 1.6 Ir 0.4O7 catalyst was slowly mixed and wetted by adding 0.6g of water and 0.01g of perfluorododecylcarboxylic acid. Then, 3g of perfluorosulfonic acid resin solution b (molar mass value of 1000, concentration of 20wt%), 4.5g of isopropanol and 1g of ethanol were added in sequence to obtain a mixed solution.

[0143] (2) The mixed solution was ultrasonically vibrated (ultrasonic power of 500W) for 20 minutes to make it uniform. Then it was ball-milled for 60 minutes (speed of 400rpm) to obtain catalyst slurry C5.

[0144] Comparative Example 6

[0145] This comparative example provides a proton exchange membrane water electrolysis catalyst slurry C6, and the preparation steps are as follows:

[0146] (1) Weigh 0.1g Ir 0.8 Co 0.2 Catalyst, 0.1g Ir 0.8 Ni 0.2 Catalyst, 1.8g Tb2Ru 1.6 Ir 0.4 For the O7 catalyst, 0.6g of water was slowly added to thoroughly mix and wet the catalyst. Then, 3g of a perfluorosulfonic acid resin solution mixture, 4.5g of isopropanol, and 1g of ethanol were added sequentially. The perfluorosulfonic acid resin solution mixture contained resin solution a (molar mass value of 700, concentration of 20wt%) and resin solution b (molar mass value of 1000, concentration of 20wt%), with a mass ratio of 1:9, i.e., 0.3g of resin solution a and 2.7g of resin solution b were added to obtain the mixed solution.

[0147] (2) The mixed solution was ultrasonically vibrated (ultrasonic power of 500W) for 20 minutes to make it uniform. Then it was ball-milled for 60 minutes (speed of 400rpm) to obtain catalyst slurry C6.

[0148] The catalyst slurries prepared in Examples 1-4 and Comparative Examples 1-6 were used to prepare the anode catalyst layer of the catalyst-coated membrane electrode (CCM), and the proton exchange membrane was a composite membrane. Finally, a single cell was assembled for water electrolysis performance testing. The test conditions were standard atmospheric pressure and a temperature of 60°C. The iridium loading of the prepared anodes was 0.32 mg / cm³. 2 The cathode Pt loading is 0.2 mg / cm³. 2 Test 2A / cm 2 The electrolysis voltage was determined. The test results for water electrolysis are shown in Table 2.

[0149] Table 2

[0150] The results in Table 2 show that the membrane electrode voltage of Examples 1-4 is lower than that of Comparative Examples 1-6, and the water electrolysis performance is significantly better than that of the membrane electrodes of Comparative Examples 1-6. This indicates that the proton exchange membrane water electrolysis anode catalyst slurry prepared in Examples 1-4 of this invention has superior performance compared to the slurry prepared in the comparative examples.

Claims

1. A proton exchange membrane water electrolysis catalyst slurry, wherein, By mass percentage, the proton exchange membrane water electrolysis catalyst slurry comprises 10-25% iridium-based catalysts of different valence states, 2-10% water, 35-65% organic alcohols, 15-35% perfluorosulfonic acid resin mixed solution, and 0.05-0.5% surfactant, with the sum of the mass percentages of each component being 100%. The iridium-based catalysts with different valence states include a first iridium-based catalyst and a second iridium-based catalyst, wherein the first iridium-based catalyst is selected from iridium-based non-noble metal doped catalysts, and the second iridium-based catalyst is selected from ruthenium-iridium-terbium oxide catalysts. The iridium-based non-noble metal doped catalyst is selected from Ir y Co 1-y and Ir z Ni 1-z One or more combinations of , wherein 0 <y<1、0<z<1; The molecular formula of the ruthenium-iridium-terbium oxidation state catalyst is Tb2Ru. x Ir 2-x O7, where 0 <x<2; The perfluorosulfonic acid resin mixed solution contains two or more perfluorosulfonic acid resin solutions with different molar mass values.

2. The proton exchange membrane water electrolysis catalyst slurry according to claim 1, wherein, The mass ratio of the first iridium-based catalyst to the second iridium-based catalyst is 1:5 to 1:

20.

3. The proton exchange membrane water electrolysis catalyst slurry according to claim 1 or 2, wherein, By mass percentage, the proton exchange membrane water electrolysis catalyst slurry comprises 15-20% iridium-based catalysts of different valence states, 4-8% water, 45-55% organic alcohols, 20-30% perfluorosulfonic acid resin mixed solution, and 0.2-1% surfactant, with the sum of the mass percentages of each component being 100%.

4. The proton exchange membrane water electrolysis catalyst slurry according to claim 1 or 2, wherein, 0.05≤x≤1.95。 5. The proton exchange membrane water electrolysis catalyst slurry according to claim 4, wherein, 0.4≤x≤1.6。 6. The proton exchange membrane water electrolysis catalyst slurry according to claim 1 or 5, wherein, The ruthenium-iridium-terbium oxidation state catalyst is selected from Tb2Ru. 1.6 Ir 0.4 O7、Tb2Ru 1.0 Ir 1.0 O7、Tb2Ru 0.4 Ir 1.6 One or more combinations of O7.

7. The proton exchange membrane water electrolysis catalyst slurry according to claim 1, wherein, The ruthenium-iridium-terbium oxidized catalyst is in particulate form with a particle size of 40-180 nm.

8. The proton exchange membrane water electrolysis catalyst slurry according to claim 1, wherein, The organic alcohol is one or a combination of two or more of ethylene glycol, glycerol, ethanol, n-propanol, and isopropanol.

9. The proton exchange membrane water electrolysis catalyst slurry according to claim 1, wherein, The surfactant is selected from at least one anionic surfactant.

10. The proton exchange membrane water electrolysis catalyst slurry according to claim 9, wherein, The anionic surfactant is one or a combination of two or more of the following: (perfluoro)alkyl or arylsulfonic acid surfactants, (perfluoro)alkyl or arylsulfonic acid surfactants, (perfluoro)alkyl or arylcarboxylic acid surfactants, and (perfluoro)alkyl or arylphosphoric acid surfactants.

11. The proton exchange membrane water electrolysis catalyst slurry according to claim 1, wherein, The perfluorosulfonic acid resin mixture contains resin solution a and resin solution b, wherein the molar mass of resin solution a is 600-900 and the molar mass of resin solution b is 900-1200.

12. The proton exchange membrane water electrolysis catalyst slurry according to claim 11, wherein, The mass ratio of resin solution a to resin solution b is 1:1 to 1:10, the concentration of resin solution a is 5% to 20%, and the concentration of resin solution b is 5% to 20%.

13. A method for preparing a proton exchange membrane water electrolysis catalyst slurry according to any one of claims 1-12, comprising the following steps: The first iridium-based catalyst and the second iridium-based catalyst were mixed with water and a surfactant, and then a perfluorosulfonic acid resin mixture and an organic alcohol were added sequentially to obtain a mixed solution. The mixed solution was subjected to ultrasonic vibration and ball milling to obtain the proton exchange membrane water electrolysis catalyst slurry.

14. The preparation method according to claim 13, wherein, The ultrasonic oscillation time is 10-30 minutes, and the ultrasonic power is 350-750W; The ball milling time is 30-120 minutes, and the rotation speed is 300-500 rpm.

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