Fluorine-doped tin dioxide and method of preparation, catalyst and method of preparation and use

Abstract

The application discloses fluorine-doped tin dioxide and a preparation method, a catalyst and a preparation method and application. The preparation method of the fluorine-doped tin dioxide comprises the following steps: adding a fluorine source into a tin salt solution to obtain a first solution; dissolving a chelating agent in a first organic solution to obtain a second solution; adding the first solution into the second solution to obtain a third solution; adding a first alkaline solution into the third solution to obtain a fourth solution; heating and evaporating the fourth solution to dryness to obtain a first dry gel, and performing first grinding on the first dry gel to obtain a solid powder; calcining the solid powder to obtain a fluorine-doped tin dioxide precursor; and performing second grinding on the fluorine-doped tin dioxide precursor to obtain the fluorine-doped tin dioxide. The fluorine-doped tin dioxide prepared by the preparation method has high specific surface area, high electrical conductivity and high stability.

Description

Technical Field

[0001] This application relates to the field of catalyst technology, and in particular to a fluorine-doped tin dioxide and its preparation method, a catalyst and its preparation method and its application. Background Technology

[0002] Proton exchange membrane (PEM) water electrolysis technology has advantages such as high current density, wide operating load, and fast response speed. Therefore, it is suitable for coupling with fluctuating renewable energy sources such as wind and solar power to achieve large-scale, efficient, and low-cost hydrogen production.

[0003] Due to the strong acidity and strong oxidizing electrochemical reaction environment of the PEM water electrolysis anode, only the expensive ruthenium-iridium metal and its oxides can currently meet the stability requirements.

[0004] However, existing iridium-based catalysts have high iridium loadings and are therefore expensive. Summary of the Invention

[0005] In view of this, this application provides a catalyst support and its preparation method, a catalyst and its preparation method, and a membrane electrode, aiming to improve the problem of high iridium loading in existing iridium-based catalysts.

[0006] The embodiments of this application are implemented as follows: A method for preparing fluorine-doped tin dioxide includes the following steps:

[0007] A fluorine source was added to a tin salt solution to obtain the first solution;

[0008] The chelating agent is dissolved in the first organic solution to obtain the second solution;

[0009] The first solution is added to the second solution to obtain a third solution;

[0010] The first alkaline solution is added to the third solution to obtain the fourth solution;

[0011] The fourth solution is heated and evaporated to dryness to obtain a first dry gel. The first dry gel is then subjected to a first grinding process to obtain a solid powder.

[0012] The solid powder was calcined to obtain a fluorine-doped tin dioxide precursor.

[0013] The fluorine-doped tin dioxide precursor is subjected to a second grinding process to obtain fluorine-doped tin dioxide.

[0014] Optionally, in some embodiments, the tin salt in the tin salt solution includes one or more of tin dichloride, tin tetrachloride pentahydrate, stannous oxalate, stannous bromide, tin tetrabromide, stannous nitrate, and stannous sulfate; and / or

[0015] The solvent in the tin salt solution includes water; and / or

[0016] The fluorine source includes one or more of NH4F, NH4HF2, and HF; and / or

[0017] The chelating agent includes acetylacetone; and / or

[0018] The first organic solvent includes an alcohol solvent, said alcohol solvent including one or more of methanol, acetone, ethanol, isopropanol, n-propanol, and ethylene glycol; and / or

[0019] The first alkaline solution comprises a first alkaline compound, which includes one or more of ammonia, NaOH, KOH, and LiOH; and / or

[0020] The solid powder contains a fluorine-doped tin dioxide preform and tin hydroxide.

[0021] Optionally, in some embodiments, the concentration of the tin salt solution is 0.7–1.5 mol / L; and / or

[0022] The concentration range of the first alkaline solution is 0.1–1 mol / L; and / or

[0023] The molar ratio of F in the fluorine source to Sn in the tin salt solution is (0.1-1):1; and / or

[0024] The volume ratio of the chelating agent to the first organic solvent is (0.3–0.5):1; and / or

[0025] The volume ratio of the first solution to the second solution is (0.8–1.4):1; and / or

[0026] The molar ratio of the first alkaline compound in the first alkaline solution to tin in the tin salt is 1:(0.9–1.1); and / or

[0027] The temperature for heating and drying is 120–160°C.

[0028] Optionally, in some embodiments, the method of adding the first solution to the second solution includes: adding the first solution dropwise to the second solution, optionally at a rate of 1–3 ml / min; and / or

[0029] The method of adding the first alkaline solution to the third solution includes dropwise addition, optionally at a rate of 1 to 3 ml / min.

[0030] Optionally, in some embodiments, the calcination method includes: heating from room temperature to the calcination temperature, and then holding at that temperature for a period of time, wherein,

[0031] The heating rate is 5–10 °C / min; and / or

[0032] The calcination temperature is 500–700°C; and / or

[0033] The heat preservation time ranges from 1 to 3 hours.

[0034] Optionally, in some embodiments, the second grinding includes: adding a fluorine-doped tin dioxide precursor, a third solvent, and grinding beads into a grinding jar for ball milling, wherein...

[0035] The third solvent includes one or more of water, ethanol, and isopropanol; and / or

[0036] The mass ratio of the fluorine-doped tin dioxide precursor to the third solvent is (0.2–0.5):1; and / or

[0037] The ratio of the total mass of the grinding beads to the sum of the masses of the fluorine-doped tin dioxide precursor and the third solvent is (4.5–7.5):1; and / or

[0038] The grinding balls include a first grinding ball, a second grinding ball, and a third grinding ball. The first grinding ball has a particle size of 3-5 mm, the second grinding ball has a particle size of 2-4 mm, and the third grinding ball has a particle size of 1-3 mm. Preferably, the mass ratio of the first grinding ball, the second grinding ball, and the third grinding ball is (1-2):(3-4):(5-6); and / or

[0039] The ball mill rotates at a speed of 400–600 rpm, and the milling time is 2–6 hours.

[0040] Accordingly, this application also provides a fluorine-doped tin dioxide, which is prepared by the method for preparing fluorine-doped tin dioxide.

[0041] Optionally, in some embodiments, the conductivity of the fluorine-doped tin dioxide is 0.05–1 S / cm; and / or

[0042] The specific surface area of ​​the fluorine-doped tin dioxide is 25–35 m². 2 / g; and / or

[0043] The fluorine-doped tin dioxide has a particle size of 20–30 nm.

[0044] Accordingly, this application also provides a method for preparing a catalyst, comprising the following steps:

[0045] The active component metal source is dissolved in water to obtain an active component metal source solution;

[0046] A second alkaline solution is added to the active component metal source solution to obtain a first catalyst precursor solution;

[0047] The first catalyst precursor solution is subjected to a first hot bath to obtain a second catalyst precursor solution;

[0048] Fluorine-doped tin dioxide prepared by the method described above is added to the second catalyst precursor solution to obtain a third catalyst precursor solution.

[0049] An acid solution is added to the third catalyst precursor solution to obtain a fourth catalyst precursor solution;

[0050] A third alkaline solution is added to the fourth catalyst precursor solution to obtain a fifth catalyst precursor solution;

[0051] The fifth catalyst precursor solution was subjected to a second hot bath, stirred until evaporated to dryness, and then ground to obtain catalyst precursor powder;

[0052] The catalyst precursor powder was calcined to obtain the catalyst.

[0053] Optionally, in some embodiments, the active component metal source includes one or more of iridium, ruthenium, rhodium, palladium, and platinum sources. Optionally, the iridium source includes one or more of chloroiridium acid, hydrated iridium trichloride, and iridium acetylacetonate; the ruthenium source includes one or more of hydrated ruthenium trichloride, ruthenium acetylacetonate, and potassium pentachlororuthenate; the rhodium source includes one or more of rhodium chloride hydrate, ammonium hexachlororhodiumate, and rhodium acetylacetonate; the palladium source includes one or more of palladium chloride, ammonium tetrachloropalladiumate, and palladium acetylacetonate; and the platinum source includes one or more of chloroplatinic acid, ammonium hexachloroplatinate, platinum acetylacetonate, potassium chloroplatinate, and ammonium tetrachloroplatinate; and / or

[0054] The second alkaline solution includes a second alkaline compound, which includes one or more of ammonia, NaOH, KOH, and LiOH; and / or

[0055] The acid in the acid solution includes one or more of HNO3, HCl, and H2SO4; and / or

[0056] The third alkaline solution includes a third alkaline compound, which includes one or more of ammonia, NaOH, KOH, and LiOH; and / or

[0057] The first catalyst precursor solution mainly contains [M(OH)]. y ] 2- Where M can be any one of Ir, Ru, Rh, Pd, Pt, 4≤y≤6; and / or

[0058] The second catalyst precursor solution mainly contains MO x ·nH2O and [M(OH)] y ] 2- Where x is 1 or 2; and / or

[0059] The fourth catalyst precursor solution mainly contains MO. x ·nH2O, where x is 1 or 2.

[0060] Optionally, in some embodiments, the concentration of the active component metal source solution is 1–5 mmol / L; and / or

[0061] The concentration of the second alkaline solution is 0.1–10 mol / L; and / or

[0062] The concentration of the acid solution is 2–3.5 mol / L; and / or

[0063] The concentration of the third alkaline solution is 0.1–10 mol / L; and / or

[0064] The pH of the first catalyst precursor solution is 12–14; and / or

[0065] The pH of the fourth catalyst precursor solution is 1–2; and / or

[0066] The pH of the fifth catalyst precursor solution is 3–5; and / or

[0067] The molar ratio of Sn in the fluorine-doped tin dioxide to the active metal source is (3.5–13.5):1.

[0068] Optionally, in some embodiments, the first heat bath is an oil bath, the temperature of which is 70–90°C and the duration is 20–60 min; and / or

[0069] The second hot bath is an oil bath, wherein the temperature of the oil bath is 80–100°C and the duration is 8–10 hours; and / or

[0070] Before adding fluorine-doped tin dioxide to the second catalyst precursor solution, the method further includes: cooling the second catalyst precursor solution in an ice-water bath; and / or

[0071] After obtaining the third catalyst precursor solution, the process further includes: stirring in an ice-water bath for 10–30 min; and / or

[0072] After obtaining the fourth catalyst precursor solution, the process further includes stirring in an ice-water bath for 20–80 minutes.

[0073] Optionally, in some embodiments, adding fluorine-doped tin dioxide prepared by the method for preparing fluorine-doped tin dioxide to the second catalyst precursor solution includes:

[0074] First, the fluorine-doped tin dioxide is dispersed in water to obtain a fluorine-doped tin dioxide dispersion. Then, the fluorine-doped tin dioxide dispersion is added to the second catalyst precursor solution. Optionally, the concentration of the fluorine-doped tin dioxide dispersion is 0.5 to 2 mg / mL.

[0075] Optionally, in some embodiments, the calcination method is as follows: heating from room temperature to the calcination temperature, and then holding at that temperature for a period of time, wherein...

[0076] The heating rate is 5–10 °C / min; and / or

[0077] The calcination temperature is 300–500°C; and / or

[0078] The heat preservation time ranges from 0.5 to 2 hours.

[0079] Accordingly, this application also provides a catalyst, which is prepared by the catalyst preparation method described above, and the catalyst includes a catalyst support and an active component supported on the catalyst support.

[0080] Optionally, in some embodiments, the catalyst support is fluorine-doped tin dioxide; and / or

[0081] The active component includes platinum group metal oxides, which include one or more of IrO2, RuO2, Rh2O3, PdO, and PtO; and / or

[0082] In the catalyst, the loading of the active component is 10–30 wt%; and / or

[0083] In the catalyst, the particle size of the active component is 2-3 nm.

[0084] Accordingly, embodiments of this application also provide a catalyst coating membrane, including a proton exchange membrane and an anodic catalyst layer and a cathode catalyst layer disposed on opposite surfaces of the proton exchange membrane, wherein the anodic catalyst layer includes a MO2 / FTO catalyst prepared by the preparation method.

[0085] Accordingly, embodiments of this application also provide a membrane electrode, the membrane electrode comprising the catalyst-coated membrane.

[0086] The fluorine-doped tin dioxide prepared by the method described in this application has a high specific surface area, high electrical conductivity, and high stability. Attached Figure Description

[0087] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0088] Figure 1 This is a flowchart of a method for preparing fluorine-doped tin dioxide provided in an embodiment of this application;

[0089] Figure 2 This is a flowchart of a catalyst preparation method provided in an embodiment of this application;

[0090] Figure 3 This is a schematic diagram of the structure of a catalyst provided in an embodiment of this application;

[0091] Figure 4 This is a schematic diagram of the structure of a catalyst coating film provided in an embodiment of this application;

[0092] Figure 5 This is a schematic diagram of a membrane electrode structure provided in an embodiment of this application;

[0093] Figure 6 These are the XRD patterns of the fluorine-doped tin dioxide precursor and the fluorine-doped tin dioxide of Example 1 of this application;

[0094] Figure 7 This is a SEM image of the fluorine-doped tin dioxide precursor of Example 1 of this application;

[0095] Figure 8 This is a SEM image of fluorine-doped tin dioxide from Example 1 of this application;

[0096] Figure 9 This is an HRTEM image of fluorine-doped tin dioxide from Example 1 of this application;

[0097] Figure 10 This is a diagram showing the conductivity and BET relationship of the fluorine-doped tin dioxide precursor, fluorine-doped tin dioxide after ball milling for 2 hours, fluorine-doped tin dioxide after ball milling for 4 hours, and fluorine-doped tin dioxide after ball milling for 6 hours in Example 1 of this application.

[0098] Figure 11 These are the XRD patterns of the IrO2 / FTO catalysts in Examples 1 and 2 of this application;

[0099] Figure 12 This is an HRTEM image of the IrO2 / FTO catalyst of Catalyst Example 1 of this application;

[0100] Figure 13 This is an HRTEM image of the IrO2 / FTO catalyst of Catalyst Example 2 of this application;

[0101] Figure 14 These are linear sweep voltammetry curves of the IrO2 / FTO catalysts in Examples 1-2 of this application and the mass activity diagrams of commercial IrO2 catalysts.

[0102] Figure 15 The polarization curves of the membrane electrodes prepared by the IrO2 / FTO catalyst of Examples 1-2 of this application and the commercial Heraeus-IrO2 / TiO2 catalyst are shown.

[0103] Figure 16 The stability test diagrams are obtained from the IrO2 / FTO catalyst of Catalyst Example 1 of this application and the commercial Heraeus-IrO2 / TiO2 catalyst, respectively.

[0104] Figure label:

[0105] Catalyst 1; FTO support 11; active component particles 12; membrane electrode 200; catalyst coated membrane 100; anode catalyst layer 10; proton exchange membrane 20; cathode catalyst layer 30; anode gas diffusion layer 40; cathode gas diffusion layer 50. Detailed Implementation

[0106] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Furthermore, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application.

[0107] In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in its actual use or operating state, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device. Furthermore, in the description of this application, the term "comprising" means "including but not limited to". The terms first, second, third, etc., are used merely as illustrative purposes and do not impose numerical requirements or establish a numerical order.

[0108] In this application, "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural.

[0109] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c," or "at least one of a, b, and c," can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0110] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0111] Commercial PEM water electrolysis devices use platinum group metal oxides, such as iridium dioxide (IrO2) or ruthenium-iridium alloy oxides, as anode catalysts for water electrolysis, with iridium dioxide and metallic iridium having a unit area concentration as high as 2 mg / cm². 2 In addition, the IrO2 in the catalyst exhibits poor reactivity, and the energy required to overcome the overpotential on the anode side accounts for 30-50% of the total energy consumption of the electrolyzer. These two factors significantly increase the equipment and operating costs of PEM water electrolysis, severely limiting its market penetration. Therefore, designing catalysts with low iridium loading, high activity, and high stability to replace currently available commercial platinum group metal oxide catalysts is of great significance.

[0112] Developing inexpensive supports for platinum group metal oxide catalysts is one of the main strategies for reducing iridium usage. The choice of support must meet the requirements of high conductivity, high specific surface area, and good stability. Carbon supports, widely used in fuel cells, are highly susceptible to oxidation and corrosion under strong acidity and high potential, making them unsuitable as anode catalyst supports for water electrolysis. Currently, research on PEM (Polymer Oxide) anode catalyst supports mainly focuses on transition metal nitrogen oxides. For example, using non-conductive supports such as titanium dioxide (TiO2) or niobium oxide, and coating their surfaces with a MO2 layer, yields core-shell structured catalysts; while using conductive supports such as titanium nitride (TiN), ATO, and ITO (Indium Tin Oxide) as catalyst supports, composite catalysts are prepared. However, when non-conductive supports such as titanium dioxide and niobium oxide are used to support platinum group metal oxides (PGMs), an additional portion of the PGMs must be sacrificed to maintain the catalyst's conductivity, performance, and stability. For example, while TiO2 exhibits good stability under strong acidity and high potential, its non-conductivity necessitates a sufficiently thick PGM layer on its surface, resulting in an iridium loading typically ≥50 wt%. Conductive catalyst supports such as TiN, ATO, and ITO undergo anodic oxidation and dissolution in acidic electrolyte solutions, precipitating dopants or tin ions, leading to structural damage and decreased conductivity. These also require a sufficiently high PGM loading (≥50 wt%) to coat the support and prevent degradation and corrosion. Furthermore, for these PGM-coated catalysts, only the surface PGMs participate in the catalytic reaction, while the inner PGMs remain unutilized, resulting in low catalyst utilization and specific current density.

[0113] In summary, the supports used in existing supported catalysts cannot simultaneously reduce the loading of platinum group metal oxides and improve the utilization rate of precious platinum group metals while maintaining both performance and stability.

[0114] The technical solution of this application is as follows:

[0115] In a first aspect, embodiments of this application provide a method for preparing fluorine-doped tin dioxide, comprising the following steps:

[0116] Step S11: Add the fluorine source to the tin salt solution and react to obtain the first solution;

[0117] Step S12: Dissolve the chelating agent in the first organic solution to obtain the second solution;

[0118] Step S13: Add the first solution to the second solution to chelate the tin ions with the chelating agent to obtain the third solution;

[0119] Step S14: Add the first alkaline solution to the third solution to react and generate fluorine-doped tin hydroxide, thus obtaining the fourth solution;

[0120] Step S15: Heat the fourth solution to evaporate it to dryness to obtain a first dry gel, and perform a first grinding on the first dry gel to obtain a solid powder;

[0121] Step S16: Calcine the solid powder to obtain a fluorine-doped tin dioxide precursor;

[0122] Step S17: Perform a second grinding on the fluorine-doped tin dioxide precursor to obtain fluorine-doped tin dioxide (FTO).

[0123] In step S11:

[0124] The tin salt solution includes tin salt and a first solvent.

[0125] In some embodiments, the tin salt includes, but is not limited to, one or more of tin dichloride, tin tetrachloride pentahydrate, tin oxalate, tin sulfide, tin tetrabromide, tin nitrate, and tin sulfide.

[0126] In some embodiments, the first solvent includes, but is not limited to, water. It is understood that the water can be pure water, deionized water, etc.

[0127] In some embodiments, the concentration range of the tin salt solution is 0.7–1.5 mol / L, for example, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1.0 mol / L, 1.1 mol / L, 1.2 mol / L, 1.3 mol / L, 1.4 mol / L, 1.5 mol / L, etc. Within this concentration range, the tin salt can dissolve effectively, which is beneficial for preparing fluorine-doped tin dioxide with high purity, resulting in fluorine-doped tin dioxide with high conductivity.

[0128] In some embodiments, the method for preparing the tin salt solution includes: adding tin salt to a first solvent and stirring at room temperature until the solution appears uniformly milky white, thereby obtaining a tin salt solution.

[0129] In some embodiments, the fluorine source includes, but is not limited to, one or more of NH4F, NH4HF2, and HF.

[0130] In some embodiments, the molar ratio of F in the fluorine source to Sn in the tin salt is (0.1–1):1, for example, 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, 1:1, etc. Within this ratio range, during subsequent reactions, most fluoride ions can be effectively doped into the tin oxide lattice, resulting in fluorine-doped tin dioxide powder with good conductivity. When the ratio is greater than this, excess free fluoride ions will corrode the crucible during calcination, and excessive fluoride ion doping will occupy defect sites in the tin oxide lattice instead of replacing O. 2- The position of the fluorine ion doping increases the carrier concentration, but this also disrupts the tin dioxide structure, reducing conductivity and stability. When the ratio is less than described, the fluorine ion doping level is too low to meet the requirement of a conductivity of 0.05–1.0 S / cm.

[0131] In some embodiments, after adding the fluorine source to the tin salt solution, the process further includes stirring at room temperature until the solution becomes clear and transparent.

[0132] When a fluorine source is added to a tin salt solution, the tin salt reacts with the fluorine source. The tin source first undergoes hydrolysis to produce a white precipitate. As more fluorine source is added, the white precipitate of basic stannous chloride dissolves, and the solution becomes clear.

[0133] In step S12:

[0134] The chelating agent includes, but is not limited to, acetylacetone. In the preparation of fluorine-doped tin dioxide, the chelating agent can play a chelating and stabilizing role, and a homogeneous sol (i.e., the fourth solution) can be obtained by controlling the hydrolysis rate.

[0135] The first organic solvent includes, but is not limited to, alcohol solvents, including, but not limited to, one or more of methanol, acetone, ethanol, isopropanol, n-propanol, and ethylene glycol.

[0136] In some embodiments, the volume ratio of the chelating agent to the first organic solvent is (0.3–0.5):1. Within this range, tin ions can be fully chelated with the chelating agent, which is beneficial for controlling the hydrolysis rate to obtain a sol (i.e., the fourth solution) with uniform composition.

[0137] In some embodiments, after dissolving the chelating agent in the first organic solution and before obtaining the second solution, the process further includes stirring at room temperature for a period of time T1. In some embodiments, T1 is 2 to 3 minutes. This facilitates the dissolution of the added chelating agent.

[0138] In step S13:

[0139] The volume ratio of the first solution to the second solution is (0.8–1.4):1, for example, 0.8:1, 0.9:1, 1.0:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, etc. Within this range, it is beneficial to maintain the homogeneity of the system.

[0140] In some embodiments, the method of adding the first solution to the second solution includes:

[0141] The first solution is added dropwise to the second solution. This helps control the hydrolysis rate and is beneficial for obtaining fluorine-doped tin dioxide with good conductivity.

[0142] In some embodiments, the dropping rate is 1–3 ml / min, for example, 1 ml / min, 1.2 ml / min, 1.5 ml / min, 1.8 ml / min, 2 ml / min, 2.3 ml / min, 2.5 ml / min, 2.7 ml / min, 3 ml / min, etc. Within this dropping rate range, it is advantageous to control the hydrolysis rate and to obtain fluorine-doped tin dioxide with good conductivity.

[0143] In step S14:

[0144] The first alkaline solution includes a first alkaline compound, which includes, but is not limited to, one or more of ammonia, NaOH, KOH, and LiOH.

[0145] The solvent in the first alkaline solution is water.

[0146] In some embodiments, the concentration range of the first alkaline solution is 0.1 to 1 mol / L, for example, 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1 mol / L, etc.

[0147] In some embodiments, the molar ratio of the first alkaline compound in the first alkaline solution to tin in the tin salt is 1:(0.9–1.1), for example, 1:0.9, 1:0.95, 1:1, 1:1.5, 1:1.5, etc. Within this range, it can be ensured that no white precipitate is formed during the dropwise addition of the second solution, avoiding the white precipitate affecting the uniformity of doping in the system, and ensuring that no excess free fluoride ions corrode the crucible or other reaction vessels during subsequent calcination.

[0148] In some embodiments, the method of adding the first alkaline solution to the third solution is dropwise addition, which facilitates the orderly progress of the reaction and is beneficial for preparing fluorine-doped tin dioxide with high stability and conductivity. In some embodiments, the dropwise addition rate is 1–3 ml / min, for example, 1 ml / min, 1.2 ml / min, 1.5 ml / min, 1.8 ml / min, 2 ml / min, 2.3 ml / min, 2.5 ml / min, 2.7 ml / min, 3 ml / min, etc.

[0149] It should be noted that a white precipitate will form in the solution immediately after the first alkaline solution is added to the third solution, and then the white precipitate will dissolve.

[0150] In some embodiments, the fourth solution is pale yellow-green.

[0151] In step S15:

[0152] The heating and drying temperature is 120–160°C, for example, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, etc. Within this heating temperature range, it is beneficial for the doped example F to have better uniformity of distribution.

[0153] In at least some embodiments, the heating and drying is carried out using a heated stirring furnace.

[0154] The solid powder contains a fluorine-doped tin dioxide preform and tin hydroxide.

[0155] In step S16:

[0156] The calcination method includes: heating from room temperature to the calcination temperature, and then holding the temperature for a period of time.

[0157] In some embodiments, the heating rate is 5 to 10 °C / min, for example, 5 °C / min, 6 °C / min, 7 °C / min, 8 °C / min, 9 °C / min, 10 °C / min, etc.

[0158] In some embodiments, the calcination temperature is 500–700°C, for example, 500°C, 520°C, 530°C, 550°C, 560°C, 580°C, 600°C, 620°C, 630°C, 650°C, 680°C, 700°C, etc.

[0159] In some embodiments, the heat preservation time ranges from 1 to 3 hours, for example, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, etc.

[0160] Within the range of heating rate, calcination temperature, and holding time, on the one hand, the solid powder can be fully calcined; on the other hand, the prepared fluorine-doped tin dioxide can have better conductivity and specific surface area; furthermore, the prepared fluorine-doped tin dioxide can have better crystallinity and thus higher stability.

[0161] In step S17:

[0162] The second grinding can be ball milling. Specifically, the fluorine-doped tin dioxide precursor, the third solvent, and the grinding balls are added to a ball milling jar for ball milling.

[0163] Because sintering and agglomeration can occur during the calcination process, the fluorine-doped tin dioxide particles have poor dispersion and small specific surface area. The ball milling can grind and disperse the sintered and agglomerated lumps into powder, effectively improving the particle dispersion and specific surface area of ​​the fluorine-doped tin dioxide particles.

[0164] The third solvent includes, but is not limited to, one or more of water, ethanol, and isopropanol.

[0165] The grinding balls include, but are not limited to, zirconia grinding balls.

[0166] In some embodiments, the mass ratio of the fluorine-doped tin dioxide precursor to the third solvent is (0.2–0.5):1, for example, 0.2:1, 0.3:1, 0.4:1, 0.5:1, etc. Within this mass ratio range, ball milling is beneficial for obtaining fluorine-doped tin dioxide with a higher specific surface area.

[0167] In some embodiments, the ratio of the total mass of the ball milling beads to the sum of the masses of the fluorine-doped tin dioxide precursor and the third solvent is (4.5–7.5):1, for example, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1, etc. Within this ratio range, it is advantageous to prepare fluorine-doped tin dioxide with good dispersibility, high conductivity, and a large specific surface area.

[0168] In some embodiments, the grinding balls include a first grinding ball, a second grinding ball, and a third grinding ball. The first grinding ball has a particle size of 3–5 mm, the second grinding ball has a particle size of 2–4 mm, and the third grinding ball has a particle size of 1–3 mm. The mass ratio of the first, second, and third grinding balls is (1–2):(3–4):(5–6). This is advantageous for preparing fluorine-doped tin dioxide with good dispersibility, high conductivity, and a large specific surface area.

[0169] In some embodiments, the ball mill rotation speed is 400–600 rpm, for example, 400 rpm, 420 rpm, 450 rpm, 580 rpm, 500 rpm, 520 rpm, 530 rpm, 550 rpm, 560 rpm, 580 rpm, 600 rpm, etc., and the ball milling time is 2–6 hours, for example, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, etc., within the range of rotation speed and time.

[0170] Within the mass ratio of the first powder, the first solvent, and the grinding beads, the addition ratio of grinding beads of different sizes, and the range of grinding speed and time, it is beneficial to prepare fluorine-doped tin dioxide particles with good dispersibility, uniform particle size, high conductivity, and large specific surface area.

[0171] The fluorine-doped tin dioxide prepared by the method described in this application has a conductivity of 0.05–1 S / cm and a specific surface area of ​​25–35 m². 2 / g, with a particle size of 20-30nm.

[0172] The fluorine-doped tin dioxide prepared by the method described in this application has a high specific surface area, high electrical conductivity, and high stability.

[0173] Secondly, embodiments of this application also provide fluorine-doped tin dioxide prepared by the above-described preparation method.

[0174] Thirdly, please refer to Figure 2 This application also provides a method for preparing a catalyst, comprising the following steps:

[0175] Step S21: Dissolve the active component metal source in water to obtain an active component metal source solution;

[0176] Step S22: Add a second alkaline solution to the active component metal source solution to cause the active component metal source to undergo a hydrolysis reaction, thereby obtaining a first catalyst precursor solution;

[0177] Step S23: The first catalyst precursor solution is subjected to a first hot bath to obtain a second catalyst precursor solution;

[0178] Step S24: Add fluorine-doped tin dioxide to the second catalyst precursor solution to obtain the third catalyst precursor solution;

[0179] Step S25: Add an acid solution to the third catalyst precursor solution to carry out an acid condensation reaction to obtain a fourth catalyst precursor solution.

[0180] Step S26: Add a third alkaline solution to the fourth catalyst precursor solution to neutralize the excess acid in the fourth catalyst precursor solution with the acid-base neutralization reaction of the third alkaline solution, thereby obtaining a fifth catalyst precursor solution.

[0181] Step S27: The fifth catalyst precursor solution is subjected to a second hot bath, stirred until evaporated, and ground to obtain catalyst precursor powder;

[0182] Step S28: Calcine the catalyst precursor powder to obtain the catalyst.

[0183] In step S21:

[0184] The active component metal source includes, but is not limited to, one or more of iridium, ruthenium, rhodium, palladium, and platinum sources.

[0185] The iridium source includes, but is not limited to, one or more of chloroiridium acid (H2IrCl6·nH2O), hydrated iridium trichloride, and iridium acetylacetonate.

[0186] The ruthenium source includes, but is not limited to, one or more of ruthenium trichloride hydrate, ruthenium acetylacetonate, and potassium pentachlororuthenate hydrate.

[0187] The rhodium source includes, but is not limited to, one or more of rhodium chloride hydrate, ammonium hexachlororhodiumate, and rhodium acetylacetonate.

[0188] The palladium source includes, but is not limited to, one or more of palladium chloride, ammonium tetrachloropalladate, and palladium acetylacetonate.

[0189] The platinum source includes, but is not limited to, one or more of chloroplatinic acid, ammonium hexachloroplatinate, platinum acetylacetonate, potassium chloroplatinate, and ammonium tetrachloroplatinate.

[0190] It is understood that the water mentioned can be pure water, deionized water, etc.

[0191] The concentration of the active component metal source solution is 1 to 5 mmol / L, for example, 1 mmol / L, 1.5 mmol / L, 2 mmol / L, 2.5 mmol / L, 3 mmol / L, 3.5 mmol / L, 4 mmol / L, 4.5 mmol / L, 5 mmol / L, etc.

[0192] In step S22:

[0193] The second alkaline solution comprises a second alkaline compound and water. The second alkaline compound includes, but is not limited to, one or more of ammonia, NaOH, KOH, and LiOH.

[0194] In some embodiments, the concentration of the second alkaline solution is 0.1 to 10 mol / L, for example, 0.1 mol / L, 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, 6 mol / L, 7 mol / L, 8 mol / L, 9 mol / L, 10 mol / L, etc.

[0195] The pH of the first catalyst precursor solution is 12-14.

[0196] The first catalyst precursor solution mainly contains [M(OH)]. y ] 2- M can be any one of Ir, Ru, Rh, Pd, and Pt, and 4≤y≤6.

[0197] In step S23:

[0198] The first heat bath is an oil bath, with a temperature of 70–90°C (e.g., 70°C, 75°C, 80°C, 85°C, 90°C), and a duration of 20–60 minutes (e.g., 20 minutes, 30 minutes, 40 minutes, 50 minutes, 60 minutes). Within this temperature and time range, the hydrolysis reaction is facilitated while minimizing MO (metabolism). x • nH2O colloidal particles are prone to aggregation and precipitation.

[0199] The first hot bath can dissolve a portion of [M(OH)] in the first catalyst precursor solution. y ] 2- MO is obtained by further deprotonation during heating. x ·nH2O, where x is 1 or 2.

[0200] The second catalyst precursor solution mainly contains MO x ·nH2O and [M(OH)] y ] 2- .

[0201] In step S24:

[0202] The molar ratio of Sn in the fluorine-doped tin dioxide to the active metal source is (3.5 to 13.5):1, for example, 3.5:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13.5:1, etc.

[0203] In some embodiments, the fluorine-doped tin dioxide is first dispersed in water to obtain a fluorine-doped tin dioxide dispersion, and then the fluorine-doped tin dioxide dispersion is added to the second catalyst precursor solution.

[0204] In some embodiments, the concentration of the fluorine-doped tin dioxide dispersion is 0.5–2 mg / mL, for example, 0.5 mg / mL, 0.8 mg / mL, 1 mg / mL, 1.2 mg / mL, 1.3 mg / mL, 1.5 mg / mL, 1.6 mg / mL, 1.8 mg / mL, 2 mg / mL, etc.

[0205] In some embodiments, before adding fluorine-doped tin dioxide to the second catalyst precursor solution, the process further includes cooling the second catalyst precursor solution in an ice-water bath. This facilitates rapid cooling, thereby stabilizing the MO in the precursor solution. x ·nH2O colloidal particles.

[0206] In some embodiments, after obtaining the third catalyst precursor solution, the process further includes stirring in an ice-water bath. This ensures that the third catalyst precursor solution is consistently maintained at 0°C, which is beneficial for the subsequent introduction of acid and for the acid condensation reaction to proceed.

[0207] In some embodiments, the ice-water bath time is 10 to 30 minutes.

[0208] In step S25:

[0209] The acid in the acid solution includes, but is not limited to, one or more of HNO3, HCl, and H2SO4.

[0210] In some embodiments, the concentration of the acid solution is 2 to 3.5 mol / L, such as 2 mol / L, 2.2 mol / L, 2.5 mol / L, 2.8 mol / L, 3 mol / L, 3.2 mol / L, 3.5 mol / L, etc.

[0211] In some embodiments, the pH of the fourth catalyst precursor solution is 1 to 2.

[0212] In some embodiments, after obtaining the fourth catalyst precursor solution, the process further includes stirring in an ice-water bath. This prevents the heat released during the acid condensation reaction from failing to dissipate in time, which could lead to MO. x • The aggregation of nH2O colloidal particles affects the final catalyst loading effect and performance.

[0213] In some embodiments, the ice-water bath time is 20 to 80 minutes.

[0214] Adding an acid solution to the third catalyst precursor solution can reduce the residual [M(OH)] in the solution. y ] 2- Convert to MO x ·nH2O.

[0215] The fourth catalyst precursor solution mainly contains MO. x ·nH2O.

[0216] In step S26:

[0217] The third alkaline solution includes a third alkaline compound, which includes, but is not limited to, one or more of ammonia, NaOH, KOH, and LiOH.

[0218] The concentration of the third alkaline solution is 0.1–10 mol / L.

[0219] The pH of the fifth catalyst precursor solution is 3–5. Within this range, MO can be adjusted. x • The types of charges on the nH2O surface enhance MO x Adsorption of nH2O on the support.

[0220] In step S27:

[0221] The second hot bath can be an oil bath. In some embodiments, the temperature of the oil bath is 80–100°C, and the duration is 8–10 hours.

[0222] In step S28:

[0223] The calcination method is as follows: the temperature is raised from room temperature to the calcination temperature, and then kept at that temperature for a period of time.

[0224] In some embodiments, the heating rate is 5 to 10 °C / min, for example, 5 °C / min, 6 °C / min, 7 °C / min, 8 °C / min, 9 °C / min, 10 °C / min, etc.

[0225] In some embodiments, the calcination temperature is 300–500°C, for example, 300°C, 320°C, 330°C, 350°C, 360°C, 380°C, 400°C, 420°C, 430°C, 450°C, 480°C, 500°C, etc.

[0226] In some embodiments, the heat preservation time ranges from 0.5 to 2 hours, for example, 0.5 hours, 1 hour, 1.5 hours, 2 hours, etc.

[0227] Within the range of heating rate, calcination temperature, and holding time, on the one hand, the catalyst precursor powder can be fully calcined; on the other hand, the prepared catalyst can have better conductivity and specific surface area; and furthermore, the prepared catalyst can have better crystallinity and thus higher stability.

[0228] In some implementations, after obtaining the catalyst, the process further includes cleaning the catalyst to remove impurities.

[0229] The cleaning process includes: placing the catalyst in an aqueous solution and sonicating it, followed by centrifugation at 8000-10000 rpm for 1-3 minutes. After centrifugation, the supernatant containing salt is poured out, and deionized water is added to cover the bottom of the catalyst. The process is repeated 3-5 times after sonication. The cleaned catalyst is then placed in an oven at 60-80°C to dry.

[0230] The catalyst preparation method described in this application uses colloids to prepare the catalyst, and the active component loading in the prepared catalyst is 10-30 wt%, and the particle size of the active component is 2-3 nm.

[0231] Fourthly, embodiments of this application also provide a catalyst prepared by the above-described catalyst preparation method.

[0232] The catalyst includes a catalyst support and an active component supported on the catalyst support.

[0233] The active components include, but are not limited to, platinum group metal oxides, which include, but are not limited to, one or more of IrO2, RuO2, Rh2O3, PdO, and PtO.

[0234] Please see Figure 3 The catalyst 1 includes an FTO support 11 and active component particles 12 loaded on the surface of the FTO support 11.

[0235] Fifthly, please refer to Figure 4 This application also provides a catalyst-coated membrane 100, which includes a proton exchange membrane 20 and an anodic catalyst layer 10 and a cathode catalyst layer 30 disposed on opposite surfaces of the proton exchange membrane 20. The anodic catalyst layer 10 includes the aforementioned catalyst.

[0236] For the sixth aspect, please refer to Figure 5 This application also provides a membrane electrode 200, which includes the catalyst-coated membrane 100, an anodic gas diffusion layer 40 disposed on the anodic catalyst layer 10 of the catalyst-coated membrane 100, and a cathode gas diffusion layer 50 disposed on the surface of the cathode catalyst layer 30 of the catalyst-coated membrane 100 away from the proton exchange membrane 20.

[0237] In a seventh aspect, embodiments of this application also provide a PEM water electrolysis hydrogen production device, including the membrane electrode 200.

[0238] The present application will be specifically described below through specific embodiments. The following embodiments are only some embodiments of the present application and are not intended to limit the present application.

[0239] Example 1

[0240] Step a: Dissolve 5g SnCl2·2H2O in 20mL of deionized water and stir at room temperature until the solution turns a uniform milky white color. Add 0.588mL of 40wt% HF solution to the above milky white solution according to the F:Sn molar ratio of 0.6:1 and stir at room temperature until the solution is clear and transparent to obtain the first solution.

[0241] Step b: Dissolve 5 ml of acetylacetone in 15 ml of methanol and stir at room temperature for 1.5 min to obtain the second solution;

[0242] Step c: Add the first solution to the second solution dropwise to obtain the third solution, while keeping the second solution stirred during the dropwise addition process;

[0243] In step d, 24 mmol of NH3·H2O with a concentration of 1 mol / L is added dropwise to the third solution. During the dropwise addition, the third solution is kept stirred. A white precipitate will be formed the instant the NH3·H2O is added to the third solution, and then it will dissolve rapidly. The solution after the dropwise addition remains clear and transparent, and has a pale yellow-green color, thus obtaining the fourth solution.

[0244] Step e: Place the fourth solution on an electromagnetic heating stirring furnace and stir and evaporate it to dryness at 140°C to obtain the first dry gel. Then, perform a first grinding on the first dry gel to obtain a solid powder.

[0245] Step f: Calcination of the solid powder, wherein the calcination is performed by heating from room temperature to 600°C at a heating rate of 8°C / min and holding at that temperature for 2 hours to obtain fluorine-doped tin dioxide precursor.

[0246] Step g: Place 1g of FTO powder and 3g of solvent water in a 50mL zirconia ball mill jar. Add the ball milling beads with sizes of 4mm, 3mm, and 2mm in proportions of 3.3g, 9.5g, and 12.3g, respectively. The ball mill speed is 500rpm and the ball milling time is 4h to obtain fluorine-doped tin dioxide.

[0247] Example 2

[0248] This embodiment is basically the same as Embodiment 1, except that in this embodiment, NH4HF2 is used to replace HF in Embodiment 1.

[0249] Example 3

[0250] This embodiment is basically the same as Embodiment 1, except that in this embodiment, the molar ratio of F in the fluorine source to Sn in the tin salt is 0.1:1.

[0251] Example 4

[0252] This embodiment is basically the same as Embodiment 1, except that in this embodiment, the molar ratio of F in the fluorine source to Sn in the tin salt is 1:1.

[0253] Example 5

[0254] This embodiment is basically the same as that in Embodiment 1, except that the amount of acetylacetone used in this embodiment is 4.5 mL.

[0255] Example 6

[0256] This embodiment is basically the same as that in Embodiment 1, except that the amount of acetylacetone used in this embodiment is 7.5 mL.

[0257] Example 7

[0258] This embodiment is basically the same as Embodiment 1, except that the amount of NH3·H2O used in this embodiment is 18 mL.

[0259] Example 8

[0260] This embodiment is basically the same as Embodiment 1, except that the amount of NH3·H2O used in this embodiment is 22 mL.

[0261] Example 9

[0262] This embodiment is basically the same as Embodiment 1, except that in this embodiment, the heating and drying temperature is 120°C.

[0263] Example 10

[0264] This embodiment is basically the same as Embodiment 1, except that in this embodiment, the heating and drying temperature is 160°C.

[0265] Example 11

[0266] This embodiment is basically the same as Embodiment 1, except that in this embodiment, the heating rate is 5℃ / min.

[0267] Example 12

[0268] This embodiment is basically the same as Embodiment 1, except that the heating rate is 10℃ / min in this embodiment.

[0269] Example 13

[0270] This embodiment is basically the same as Embodiment 1, except that the calcination temperature in this embodiment is 500℃.

[0271] Example 14

[0272] This embodiment is basically the same as Embodiment 1, except that the calcination temperature in this embodiment is 700℃.

[0273] Example 15

[0274] This embodiment is basically the same as Embodiment 1, except that in this embodiment, the total mass of the grinding beads is 18g.

[0275] Example 16

[0276] This embodiment is basically the same as Embodiment 1, except that the total mass of the grinding beads in this embodiment is 30g.

[0277] Example 17

[0278] This embodiment is basically the same as Embodiment 1, except that the ball mill speed is 400 rpm in this embodiment.

[0279] Example 18

[0280] This embodiment is basically the same as Embodiment 1, except that the ball mill speed is 600 rpm in this embodiment.

[0281] XRD test:

[0282] XRD tests were performed on the fluorine-doped tin dioxide precursor and the fluorine-doped tin dioxide in Example 1, respectively, to obtain... Figure 6 The XRD patterns of the fluorine-doped tin dioxide precursor and the fluorine-doped tin dioxide are shown.

[0283] Depend on Figure 6 It can be seen that the crystal form of fluorine-doped tin dioxide did not change significantly before and after ball milling, and it was a well-crystallized rutile phase, indicating that ball milling does not destroy the crystal form of fluorine-doped tin dioxide.

[0284] SEM test:

[0285] SEM measurements were performed on the fluorine-doped tin dioxide precursor and the fluorine-doped tin dioxide in Example 1, respectively, to obtain... Figures 7-8 The SEM images of the fluorine-doped tin dioxide precursor and the fluorine-doped tin dioxide are shown.

[0286] Depend on Figures 7-8 It can be seen that the fluorine-doped tin dioxide after ball milling has no agglomeration, smaller particle size, and a narrower particle size distribution.

[0287] HRTEM test

[0288] HRTEM tests were performed on the fluorine-doped tin dioxide in Example 1 to obtain... Figure 9 The image shown is an HRTEM image of fluorine-doped tin dioxide.

[0289] Depend on Figure 9 It can be seen that the fluorine-doped tin dioxide in Example 1 has both small particle size and good crystallinity.

[0290] Conductivity and BET test

[0291] The conductivity and BET of the fluorine-doped tin dioxide precursor (Pristine) in Example 1, as well as the fluorine-doped tin dioxide obtained after ball milling the fluorine-doped tin dioxide precursor for 2 hours, 4 hours, and 6 hours respectively, were measured to obtain the following results. Figure 10 The conductivity graph and BET relationship graph shown are used to obtain the conductivity and BET shown in Table 1.

[0292] Depend on Figure 10 As shown in Table 1, different ball milling times have no significant effect on the conductivity of fluorine-doped tin dioxide. With the extension of ball milling time, the specific surface area of ​​fluorine-doped tin dioxide also increases, which is because the increase in ball milling time makes the particle size of fluorine-doped tin dioxide more uniform.

[0293] Table 1:

[0294]

[0295] Catalyst Example 1

[0296] Step A: Dissolve the active component metal source H2IrCl6·nH2O in deionized water to prepare an active component metal source solution with a concentration of 2 mmol / L;

[0297] Step B: Add a 3 mol / L NaOH solution to the active component metal source solution, adjust the pH to 13, and stir at room temperature until the solution changes from wine red to yellow to obtain the first catalyst precursor solution.

[0298] Step C: Place the first catalyst precursor solution in an oil bath and stir and heat it. The oil bath temperature is 90°C and the holding time is 30 minutes. After heating, the solution changes from yellow to blue, and the second catalyst precursor solution is obtained.

[0299] Step D: Cool the second catalyst precursor solution in an ice-water bath, then pour 100 mL of FTO aqueous dispersion with a concentration of 1 mg / mL into the second catalyst precursor solution, wherein the FTO in the FTO aqueous dispersion is the FTO powder prepared in Example 1, to obtain the third catalyst precursor solution, and stir the third catalyst precursor solution in an ice-water bath for 20 min.

[0300] Step E: Quickly pour a 3 mol / L HNO3 aqueous solution into the third catalyst precursor solution to obtain a fourth catalyst precursor solution with a pH of 1. Place the fourth catalyst precursor solution in an ice-water bath and stir for 60 min.

[0301] Step F: Add a 1 mol / L NaOH solution to the fourth catalyst precursor solution to obtain a fifth catalyst precursor solution with a pH of 4.

[0302] Step G: Place the fifth catalyst precursor solution in an oil bath at 90°C and heat and stir until it evaporates to dryness. Grind the solution to obtain catalyst precursor powder.

[0303] Step H: The catalyst precursor powder is calcined in an air atmosphere. The calcination is carried out by heating from room temperature to the calcination temperature and then holding it at that temperature. The heating rate is 8℃ / min, the calcination temperature is 400℃, and the holding time is 1h, to obtain unpurified IrO2 / FTO catalyst.

[0304] Step 1: Place the unpurified IrO2 / FTO catalyst in an aqueous solution and sonicate for 20 min, followed by centrifugation at 10,000 rpm for 3 min. After centrifugation, discard the salt-containing supernatant, add deionized water to cover the bottom of the catalyst, sonicate for 20 min, and repeat the centrifugation process 5 times. After washing, place the catalyst in an 80℃ oven and dry overnight to obtain the IrO2 / FTO catalyst.

[0305] Catalyst Examples 2-18

[0306] Catalyst Examples 2-18 are basically the same as Catalyst Example 1, except that the FTO prepared in Examples 2-18 is used instead of the FTO prepared in Example 1.

[0307] Catalyst Example 19

[0308] Catalyst Example 19 is basically the same as Catalyst Example 1, except that RuCl3·3H2O is used to replace H2IrCl6·nH2O in Catalyst Example 1. Correspondingly, the catalyst prepared in this example is a RuO2 / FTO catalyst.

[0309] Catalyst Example 20

[0310] Catalyst Example 20 is basically the same as Catalyst Example 1, except that RhCl3·mH2O is used to replace H2IrCl6·nH2O in Catalyst Example 1. Correspondingly, the catalyst prepared in this example is a Rh2O3 / FTO catalyst.

[0311] Catalyst Example 21

[0312] Catalyst Example 21 is basically the same as Catalyst Example 1, except that (NH4)2PdCl4 is used to replace H2IrCl6·nH2O in Catalyst Example 1. Correspondingly, the catalyst prepared in this example is a PdO / FTO catalyst.

[0313] Catalyst Example 22

[0314] Catalyst Example 22 is basically the same as Catalyst Example 1, except that H2PtCl6·mH2O is used to replace H2IrCl6·nH2O in Catalyst Example 1. Correspondingly, the catalyst prepared in this example is a PtO2 / FTO catalyst.

[0315] Catalyst Comparative Examples 1-7

[0316] The catalyst comparative examples 1 to 7 are basically the same as those in catalyst example 1, except that the FTO prepared in comparative examples 1 to 7 is replaced with the FTO prepared in example 1.

[0317] XRD test:

[0318] The IrO2 / FTO catalysts prepared in Examples 1 and 2 were subjected to XRD tests, and the results were obtained. Figure 11 The XRD pattern shown.

[0319] Depend on Figure 11 It can be seen that there is no obvious IrO2 peak, indicating that the fluorine-doped tin dioxide supported iridium oxide in catalyst Examples 1-2 has the characteristics of low loading and small particle size.

[0320] HRTEM test

[0321] HRTEM tests were performed on the IrO2 / FTO catalysts in Examples 1 and 2, and the results were obtained. Figures 12-13 The HRTEM diagram shown.

[0322] Depend on Figures 12-13 It can be seen that IrO2 / FTO is composed of iridium oxide particles with a particle size of 1-2 nm and good crystallinity anchored in the form of single particles on the surface of fluorine-doped tin dioxide, a conductive carrier.

[0323] Catalyst activity test

[0324] The IrO2 / FTO catalysts in Examples 1 and 2, as well as a commercial IrO2 catalyst (Annegi Chemical & 3A (Anhui Zesheng Technology Co., Ltd.)), were subjected to linear sweep voltammetry curve mass activity testing to obtain... Figure 14The linear sweep voltammetry curve mass activity map (LSV) is described.

[0325] Depend on Figure 14 It can be seen that, compared with commercial IrO2 catalysts, the catalysts of Examples 1-2 of this application have significantly higher catalytic activity.

[0326] Membrane electrode testing

[0327] Membrane electrodes were prepared using the IrO2 / FTO catalysts from Catalyst Examples 1 and 2, and a commercial Heraeus-IrO2 / TiO2 catalyst, respectively. The membrane electrodes consisted of a cathode side of 40 wt% Pt / C, a proton exchange membrane of Nafion@115, and an anode side of either an IrO2 / FTO catalyst or a commercial Heraeus-IrO2 / TiO2 catalyst.

[0328] Polarization curves were tested on the membrane electrodes prepared using the IrO2 / FTO catalysts from Examples 1-2 and the commercial Heraeus-IrO2 / TiO2 catalyst, respectively, to obtain... Figure 15 The polarization curves shown are shown.

[0329] Depend on Figure 15 It can be seen that IrO2 / FTO achieves better performance than the commercial Heraeus-IrO2 / TiO2 catalyst with a lower Ir loading, under PEM electrolyzer operating conditions of 80℃@2A / cm. 2 Below, the cell voltage difference in the electrolytic cell is 68mV.

[0330] Stability tests were conducted on the membrane electrode prepared using the IrO2 / FTO catalyst of Catalyst Example 1 and the membrane electrode prepared using the commercial Heraeus-IrO2 / TiO2 catalyst. Figure 16 The stability test diagram is shown.

[0331] Depend on Figure 16 It can be seen that the membrane electrode prepared by the IrO2 / FTO catalyst in Catalyst Example 1 has significantly better stability than the membrane electrode prepared by the commercial Heraeus-IrO2 / TiO2 catalyst.

[0332] The technical solutions provided by the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for preparing a catalyst, characterized in that, Includes the following steps: A fluorine source was added to a tin salt solution to obtain the first solution; The chelating agent is dissolved in a first organic solvent to obtain a second solution; The first solution is added to the second solution to obtain a third solution; The first alkaline solution is added to the third solution to obtain the fourth solution; The fourth solution is heated and evaporated to dryness to obtain a first dry gel. The first dry gel is then subjected to a first grinding process to obtain a solid powder. The solid powder was calcined to obtain a fluorine-doped tin dioxide precursor. The fluorine-doped tin dioxide precursor is subjected to a second grinding process to obtain fluorine-doped tin dioxide; The active component metal source is dissolved in water to obtain an active component metal source solution; A second alkaline solution is added to the active component metal source solution to obtain a first catalyst precursor solution; The first catalyst precursor solution is subjected to a first hot bath to obtain a second catalyst precursor solution; The fluorine-doped tin dioxide was added to the second catalyst precursor solution to obtain the third catalyst precursor solution; An acid solution is added to the third catalyst precursor solution to obtain a fourth catalyst precursor solution; A third alkaline solution is added to the fourth catalyst precursor solution to obtain a fifth catalyst precursor solution; The fifth catalyst precursor solution was subjected to a second hot bath, stirred until evaporated to dryness, and then ground to obtain catalyst precursor powder; The catalyst precursor powder was calcined to obtain the catalyst. The pH of the fourth catalyst precursor solution is 1~2; The pH of the fifth catalyst precursor solution is 3-5.

2. The preparation method according to claim 1, characterized in that, The tin salt in the tin salt solution includes one or more of tin dichloride, tin tetrachloride pentahydrate, stannous oxalate, stannous bromide, stannous tetrabromide, stannous nitrate, and stannous sulfate; and / or The solvent in the tin salt solution includes water; and / or The fluorine source includes one or more of NH4F, NH4HF2, and HF; and / or The chelating agent includes acetylacetone; and / or The first organic solvent includes an alcohol solvent, said alcohol solvent including one or more of methanol, acetone, ethanol, isopropanol, n-propanol, and ethylene glycol; and / or The first alkaline solution comprises a first alkaline compound, which includes one or more of ammonia, NaOH, KOH, and LiOH; and / or The solid powder contains a fluorine-doped tin dioxide preform and tin hydroxide.

3. The preparation method according to claim 1, characterized in that, The concentration of the tin salt solution is 0.7~1.5 mol / L; and / or The concentration range of the first alkaline solution is 0.1~1 mol / L; and / or The molar ratio of F in the fluorine source to Sn in the tin salt solution is (0.1~1):1; and / or The volume ratio of the chelating agent to the first organic solvent is (0.3~0.5):1; and / or The volume ratio of the first solution to the second solution is (0.8~1.4):1; and / or The molar ratio of the first alkaline compound in the first alkaline solution to tin in the tin salt is 1:(0.9~1.1); and / or The heating and drying temperature is 120~160℃.

4. The preparation method according to claim 1, characterized in that, The method of adding the first solution to the second solution includes: adding the first solution dropwise to the second solution at a rate of 1-3 ml / min; and / or The method of adding the first alkaline solution to the third solution includes dripping, wherein the dripping rate is 1~3 ml / min.

5. The preparation method according to claim 1, characterized in that, The calcination method includes: heating from room temperature to the calcination temperature, and then holding at that temperature for a period of time, wherein... The heating rate is 5~10℃ / min; and / or The calcination temperature is 500~700℃; and / or The heat preservation time ranges from 1 to 3 hours.

6. The preparation method according to claim 1, characterized in that, The second grinding process includes: adding a fluorine-doped tin dioxide precursor, a third solvent, and grinding beads into a grinding jar for ball milling, wherein... The third solvent includes one or more of water, ethanol, and isopropanol; and / or The mass ratio of the fluorine-doped tin dioxide precursor to the third solvent is (0.2~0.5):1; and / or The ratio of the total mass of the grinding beads to the sum of the masses of the fluorine-doped tin dioxide precursor and the third solvent is (4.5~7.5):1; and / or The grinding balls include a first grinding ball, a second grinding ball, and a third grinding ball. The first grinding ball has a particle size of 3-5 mm, the second grinding ball has a particle size of 2-4 mm, and the third grinding ball has a particle size of 1-3 mm. The mass ratio of the first grinding ball to the second grinding ball is (1-2):(3-4):(5-6); and / or The ball mill rotates at a speed of 400-600 rpm, and the milling time is 2-6 hours.

7. The preparation method according to claim 1, characterized in that, The conductivity of the fluorine-doped tin dioxide is 0.05~1 S / cm; and / or The specific surface area of ​​the fluorine-doped tin dioxide is 25~35 m² / g; and / or The fluorine-doped tin dioxide has a particle size of 20~30 nm.

8. The preparation method according to claim 7, characterized in that, The active component metal source includes one or more of iridium, ruthenium, rhodium, palladium, and platinum sources; the iridium source includes one or more of chloroiridium acid, hydrated iridium trichloride, and iridium acetylacetonate; the ruthenium source includes one or more of hydrated ruthenium trichloride, ruthenium acetylacetonate, and potassium pentachlororuthenate; the rhodium source includes one or more of rhodium chloride hydrate, ammonium hexachlororhodiumate, and rhodium acetylacetonate; the palladium source includes one or more of palladium chloride, ammonium tetrachloropalladiumate, and palladium acetylacetonate; and the platinum source includes one or more of chloroplatinic acid, ammonium hexachloroplatinate, platinum acetylacetonate, potassium chloroplatinate, and ammonium tetrachloroplatinate; and / or The second alkaline solution includes a second alkaline compound, which includes one or more of ammonia, NaOH, KOH, and LiOH; and / or The acid in the acid solution includes one or more of HNO3, HCl, and H2SO4; and / or The third alkaline solution includes a third alkaline compound, which includes one or more of ammonia, NaOH, KOH, and LiOH; and / or The first catalyst precursor solution mainly contains [M(OH)]. y ] 2- Where M is any one of Ir, Ru, Rh, Pd, and Pt, 4≤y≤6; and / or The second catalyst precursor solution mainly contains MO x ·nH2O and [M(OH)] y ] 2- Where x is 1 or 2; and / or The fourth catalyst precursor solution mainly contains MO. x ·nH2O, where x is 1 or 2.

9. The preparation method according to claim 1, characterized in that, The concentration of the active component metal source solution is 1~5 mmol / L; and / or The concentration of the second alkaline solution is 0.1~10 mol / L; and / or The concentration of the acid solution is 2~3.5 mol / L; and / or The concentration of the third alkaline solution is 0.1~10 mol / L; and / or The pH of the first catalyst precursor solution is 12-14; and / or The molar ratio of Sn in the fluorine-doped tin dioxide to the active metal source is (3.5~13.5):

1.

10. The preparation method according to claim 1, characterized in that, The first hot bath is an oil bath, wherein the temperature of the oil bath is 70~90℃ and the time is 20~60 min; and / or The second hot bath is an oil bath, the temperature of which is 80~100℃ and the time is 8~10 h; and / or Before adding fluorine-doped tin dioxide to the second catalyst precursor solution, the method further includes: cooling the second catalyst precursor solution in an ice-water bath; and / or After obtaining the third catalyst precursor solution, the process further includes: stirring in an ice-water bath for 10-30 minutes; and / or After obtaining the fourth catalyst precursor solution, the process further includes stirring in an ice-water bath for 20-80 minutes.

11. The preparation method according to claim 1, characterized in that, The addition of the fluorine-doped tin dioxide to the second catalyst precursor solution includes: The fluorine-doped tin dioxide was dispersed in water to obtain a fluorine-doped tin dioxide dispersion, and then the fluorine-doped tin dioxide dispersion was added to the second catalyst precursor solution. The concentration of the fluorine-doped tin dioxide dispersion is 0.5~2 mg / mL.

12. The preparation method according to claim 1, characterized in that, The calcination method is as follows: the temperature is raised from room temperature to the calcination temperature, and then held at that temperature for a period of time, wherein... The heating rate is 5~10℃ / min; and / or The calcination temperature is 300~500℃; and / or The heat preservation time ranges from 0.5 to 2 hours.

13. A catalyst, characterized in that, The catalyst is prepared by the preparation method according to any one of claims 1 to 12, and the catalyst includes a catalyst support and an active component supported on the catalyst support.

14. The catalyst according to claim 13, characterized in that, The catalyst support is fluorine-doped tin dioxide; and / or The active component includes platinum group metal oxides, which include one or more of IrO2, RuO2, Rh2O3, PdO, and PtO; and / or In the catalyst, the loading of the active component is 10-30 wt%; and / or In the catalyst, the particle size of the active component is 2~3 nm.

15. A catalyst-coated membrane, comprising a proton exchange membrane and an anodic catalyst layer and a cathode catalyst layer disposed on opposite surfaces of the proton exchange membrane, characterized in that, The anode catalyst layer includes a catalyst prepared by the preparation method according to any one of claims 1 to 12.

16. A membrane electrode, characterized in that, The membrane electrode comprises the catalyst-coated membrane as described in claim 15.

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