A supported iridium catalyst, its preparation method and use

Abstract

The present application relates to a kind of supported iridium catalyst and its preparation method and application, wherein the catalyst includes titanium oxide carrier and metal iridium supported on the carrier;The XRD spectrum of the catalyst has the characteristic peak of metal iridium, and there is no characteristic peak of titanium oxide.The catalyst of the present application is used to catalyze anodic oxygen evolution reaction, and the catalytic activity is high, the stability is good, and the iridium consumption can be significantly reduced.The preparation process of the catalyst of the present application is simple, and it is easy to control, which is beneficial to large-scale batch production.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen production by water electrolysis, and in particular to a supported iridium catalyst, a preparation method thereof, and application thereof in hydrogen production technology by water electrolysis using a proton exchange membrane. Background Art

[0002] Renewable energy sources (such as wind and solar) are highly dependent on natural conditions. Converting them into easily storable hydrogen can more efficiently utilize these energies and contribute to addressing global energy and environmental challenges. Proton exchange membrane water electrolysis hydrogen production technology offers advantages such as high efficiency, compact size, fast start-up and shutdown, and a wide operating range. However, this technology is more expensive than the currently popular alkaline water electrolysis method, limiting its large-scale application.

[0003] In proton exchange membrane water electrolysis hydrogen production technology, the cathode catalyst is commonly used as a platinum-carbon catalyst, which can achieve good results at a low metal loading; while the anode kinetic process is slow, requiring a high overpotential to drive the electrochemical reaction. Commonly used anode catalysts are iridium black and iridium dioxide. Iridium black has higher catalytic activity but poorer stability under strong acid and high oxygen evolution potentials; iridium oxide has better stability but relatively lower catalytic activity. In addition, the iridium dosage of existing electrolytic cells is generally higher than 2mg / cm 2 However, iridium is expensive and scarce, so reducing the overpotential of the oxygen evolution reaction and reducing the amount of iridium are one of the keys to achieving large-scale application of proton exchange membrane water electrolysis hydrogen production technology.

[0004] While some studies have reported using crystalline titanium dioxide as a support for iridium oxide as anode catalysts, these catalysts still suffer from high overpotentials and unsatisfactory stability in strong acid and high potential conditions. To date, there have been no reports of using amorphous titanium dioxide as a support for metallic iridium as anode catalysts. Summary of the Invention

[0005] The present invention provides an iridium catalyst having high stability and higher catalytic activity when used in the anodic oxygen evolution reaction at the electrolysis of water. Another object of the present invention is to provide a simple method for preparing the catalyst and to reduce the amount of iridium used.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] 1. A supported iridium catalyst comprising a titanium dioxide carrier and metallic iridium supported on the carrier; the XRD spectrum of the catalyst has characteristic peaks of metallic iridium but no characteristic peaks of titanium dioxide.

[0008] 2. According to any of the above catalysts, the catalyst is composed of titanium dioxide and metallic iridium.

[0009] 3. According to any of the aforementioned catalysts, wherein the XRD spectrum of the catalyst contains only characteristic peaks of metallic iridium.

[0010] 4. According to any of the aforementioned catalysts, wherein, based on the mass of the catalyst, the mass fraction of iridium is 50% to 60%, and the mass fraction of titanium is 24% to 30%.

[0011] 5. According to any of the aforementioned catalysts, wherein the particle size of the metal iridium in the catalyst is 2 nm to 3 nm.

[0012] 6. According to any of the aforementioned catalysts, lattice fringes of titanium dioxide are visible in the TEM spectrum of the catalyst.

[0013] 7. According to any of the aforementioned catalysts, wherein the titanium dioxide support has an X-ray diffraction pattern as shown in the following table:

[0014]

[0015]

[0016] 8. According to any of the above catalysts, wherein the titanium dioxide carrier O 1s In the XPS spectrum, there are three characteristic peaks at 532.8±0.1eV, 531.4±0.1eV and 529.6±0.1eV, respectively. Among them, the peak area of ​​the characteristic peak at 531.4±0.1eV accounts for 20% to 25% of the total peak area of ​​the three.

[0017] 9. According to any of the above catalysts, wherein the Ir 4f In the XPS spectrum, there are two characteristic peaks at 60.7±0.1eV and 63.7±0.1eV, respectively.

[0018] 10. A catalyst according to any preceding claim, wherein the resistivity of the titania support is less than that of crystalline titania.

[0019] 11. A method for preparing a supported iridium catalyst, comprising:

[0020] (1) dispersing a titanium dioxide carrier and a surfactant in a liquid reducing agent to obtain a suspension;

[0021] (2) adding an iridium metal precursor to the suspension, reacting at a temperature above the reduction temperature, and separating to obtain a supported iridium catalyst after the reaction is completed;

[0022] The titanium dioxide carrier has an X-ray diffraction pattern as shown in the following table:

[0023] 2θ(°) <![CDATA[I / I0(%)]]> 10±0.4 Vs 24±0.4 w 28±0.4 m 48±0.4 m 61±0.4 w

[0024] 12. A preparation method according to any of the above, wherein the surfactant is a quaternary ammonium salt containing at least one C12-C18 alkyl group.

[0025] 13. A preparation method according to any of the above, wherein the liquid reducing agent is one or more of propylene glycol, glycerol and benzyl alcohol.

[0026] 14. According to any of the aforementioned preparation methods, the preparation method of the titanium dioxide carrier comprises: dissolving citric acid and a titanium source in water; adjusting the pH value to 7-10 (preferably 8-9), reacting; removing the solvent to obtain a solid, and calcining the solid to obtain the titanium dioxide carrier.

[0027] 15. A catalyst, wherein the catalyst is prepared by any of the above-mentioned methods for preparing the catalyst.

[0028] 16. Use of any of the above catalysts as an oxygen evolution electrocatalyst in electrochemistry.

[0029] 17. A proton exchange membrane water electrolyzer comprising a proton exchange membrane, a cathode catalyst layer, an anode catalyst layer, a cathode diffusion layer and an anode diffusion layer, wherein any of the aforementioned catalysts is used in the anode catalyst layer.

[0030] 18. A method for producing hydrogen by electrolyzing water, wherein any of the aforementioned catalysts or the aforementioned proton exchange membrane water electrolyzer is used.

[0031] Compared with existing technologies, the present invention has the following beneficial technical effects: when used to catalyze the anodic oxygen evolution reaction, the catalyst of the present invention not only exhibits good stability but also high catalytic activity, significantly reducing the amount of iridium required in the electrolyzer, thereby significantly reducing the cost of proton exchange membrane water electrolysis technology. The catalyst of the present invention has a simple preparation process, is easy to control, and can be produced on a large scale.

[0032] Other features and advantages of the present invention will be described in detail in the detailed description section. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is the XRD pattern of the titanium dioxide support prepared in Preparation Example 1 of the present invention.

[0034] Figure 2 This is a TEM image of the titanium dioxide support prepared in Preparation Example 1 of the present invention.

[0035] Figure 3 This is the BET diagram of the titanium dioxide support prepared in Preparation Example 1 of the present invention.

[0036] Figure 4The titanium dioxide carrier prepared in Preparation Example 1 of the present invention is O 1s XPS graph.

[0037] Figure 5 The titanium dioxide carrier Ti prepared in Preparation Example 1 of the present invention 2p3 / 2 XPS graph.

[0038] Figure 6 This is the XRD pattern of the titanium dioxide support prepared in Preparation Example 2 of the present invention.

[0039] Figure 7 This is the XRD pattern of the titanium dioxide support prepared in Preparation Example 3 of the present invention.

[0040] Figure 8 This is the XRD pattern of commercial anatase titanium dioxide.

[0041] Figure 9 O is the commercial anatase titanium dioxide 1s XPS graph.

[0042] Figure 10 This is a resistivity test chart of the titanium dioxide support prepared in Preparation Example 1 of the present invention and commercial anatase titanium dioxide.

[0043] Figure 11 This is the XRD pattern of the catalyst prepared in Preparation Example 4 of the present invention.

[0044] Figure 12 This is a TEM image of the catalyst prepared in Preparation Example 4 of the present invention.

[0045] Figure 13 The Ir of the catalyst prepared in Preparation Example 4 of the present invention 4f XPS graph.

[0046] Figure 14 These are the anodic polarization curves of the catalyst prepared in Preparation Example 4 of the present invention, the catalyst in Comparative Example 1, and a commercial iridium dioxide catalyst.

[0047] Figure 15 The anodic polarization curves of the catalyst prepared in Preparation Example 4 of the present invention and the commercial iridium dioxide catalyst before and after cycling are shown. DETAILED DESCRIPTION

[0048] The present invention is described in detail below in conjunction with specific embodiments. However, it should be noted that the protection scope of the present invention is not limited by these specific embodiments and principle explanations, but is determined by the claims.

[0049] In the present invention, except for the contents explicitly described, any matters or issues not mentioned are directly applicable to those known in the art without any changes. Moreover, any embodiment described herein can be freely combined with one or more other embodiments described herein, and the technical solutions or technical concepts formed thereby are considered part of the original disclosure or description of the present invention and should not be regarded as new content not disclosed or anticipated herein, unless a person skilled in the art considers that the combination is obviously unreasonable.

[0050] All features disclosed in the present invention may be combined in any combination, and such combinations should be understood as disclosed or described in the present invention. Unless a person skilled in the art considers such combination to be obviously unreasonable, such combinations should be considered as specifically disclosed and described in the present invention. The numerical values ​​disclosed in this specification, unless otherwise specified, include not only the numerical values ​​specifically disclosed in the examples but also the endpoints of the numerical ranges in the specification. Any combination of these numerical values ​​should be considered as the range disclosed or described in the present invention.

[0051] Technical and scientific terms in the present invention shall be understood according to their definitions if they are defined, and shall be understood according to their general meanings in the art if they are not defined.

[0052] Unless otherwise specified, the numerical ranges defined herein include the endpoints of the numerical ranges.

[0053] In the present invention, unless otherwise specified, the term "soluble" means soluble in the solvent used.

[0054] In the present invention, "optionally" means "with" or "without", for example, A and optionally B means "A and not including B" or "A and B".

[0055] In the present invention, the intensity of the characteristic peak in the XRD pattern is determined by the integrated area of ​​the diffraction peak after subtracting the background. I0 is the intensity of the strongest characteristic peak, and I is the intensity of each of the other characteristic peaks. It should be noted that the parameter 2θ is subject to both human and instrumental errors, so an uncertainty of ±0.4° is assigned in the table. The relative intensity of the characteristic peak is represented by the symbols vs, s, m, and w, representing very strong, strong, medium, and weak, respectively. Based on 100×(I / I0), the above symbols and names are specifically defined as:

[0056] Vs=80~100, s=40~80, m=25~40, w=0.01~25.

[0057] (1) Preparation of titanium dioxide support

[0058] The present application provides a preparation method of titanium dioxide carrier, comprising: dissolving polybasic organic carboxylic acid and / or polybasic organic carboxylic acid salt and titanium source in water; the pH value of the solution is 7-10, and then reacting; removing the solvent to obtain a solid, and then calcining the solid to obtain the titanium dioxide carrier.

[0059] In the preparation method of the carrier, the polybasic organic carboxylic acid is preferably citric acid.

[0060] In the preparation method of the carrier, when the pH value needs to be adjusted by alkali, the alkali can be selected from one or more of sodium carbonate, sodium bicarbonate, sodium hydroxide and ammonia.

[0061] In the preparation method of the carrier, the pH value of the solution is preferably controlled to 8-9.

[0062] In the preparation method of the carrier, the titanium source can be selected from one or more of titanium sulfate, titanium tetrachloride, tetraethyl titanate and tetrabutyl titanate.

[0063] In the preparation method of the carrier, the molar ratio of citric acid to titanium source is preferably 2:(0.5-2) in terms of titanium atoms.

[0064] In the preparation method of the carrier, the amount of the titanium source is used to make the molar concentration of the titanium source in the solution be 0.1M-1M in terms of titanium atoms.

[0065] In the preparation method of the carrier, the reaction temperature is generally 80-100℃, and the reaction time is generally 4-18h.

[0066] In the preparation method of the carrier, the solvent can be removed by a conventional method, and the solvent is preferably removed by rotary distillation.

[0067] In the preparation method of the carrier, the solid obtained after removing the solvent is preferably dried, and then calcined.

[0068] In the preparation method of the carrier, the calcination is carried out in an oxygen-containing atmosphere (such as air or a mixture of air and oxygen), and the temperature is generally 400-600℃, and the time is generally 2-6h.

[0069] In the preparation method of the carrier, the solid after calcination can be subjected to suitable post-treatment, such as washing, drying, etc. The washing can be carried out by using water or a mixed solvent of water and ethanol until the pH value is neutral.

[0070] The present application also provides a titanium dioxide carrier prepared by the above method.

[0071] The XRD pattern of the titanium dioxide carrier has the X-ray diffraction pattern shown in the following table:

[0072] 2θ(°) <![CDATA[I / I0(%)]]> 10±0.4 Vs 24±0.4 w 28±0.4 m 48±0.4 m 61±0.4 w .

[0073] The specific surface area of ​​the titanium dioxide carrier is generally 150m 2 / g~250m 2 / g.

[0074] In the TEM spectrum of the titanium dioxide carrier, most of the structure is a cotton-like amorphous structure, but a small amount of titanium dioxide lattice fringes can be seen.

[0075] The titanium dioxide support O 1s The XPS spectrum shows three characteristic peaks at 532.8±0.1eV, 531.4±0.1eV, and 529.6±0.1eV, respectively. The peak area at 531.4±0.1eV accounts for 20% to 25% of the total peak area of ​​the three peaks. In contrast, the peak area at 531.4±0.1eV in existing crystalline titanium dioxide, such as anatase, accounts for less than 20% of the total peak area of ​​the three peaks.

[0076] The resistivity of the titanium dioxide carrier is 10 kΩ·cm to 15 kΩ·cm, which is lower than the resistivity of crystalline titanium dioxide (such as anatase titanium dioxide or rutile titanium dioxide).

[0077] (2) Preparation of supported iridium catalyst

[0078] The present invention provides a method for preparing a supported iridium catalyst, comprising:

[0079] (1) dispersing a titanium dioxide carrier and a surfactant in a liquid reducing agent to obtain a suspension;

[0080] (2) adding an iridium metal precursor to the suspension, reacting at a temperature above the reduction temperature, and obtaining a supported iridium catalyst by separation after the reaction is completed.

[0081] In the preparation method of the iridium catalyst, the carrier is the titanium dioxide carrier described in (1).

[0082] In the preparation method of the catalyst, the surfactant is a quaternary ammonium salt containing at least one C12-C18 straight-chain alkyl group, preferably one or more of octadecyltrimethylammonium chloride (or ammonium bromide), hexadecyltrimethylammonium chloride (or ammonium bromide) and tetradecyltrimethylammonium chloride (or ammonium bromide).

[0083] In the catalyst preparation method, the liquid reducing agent is preferably one or more of propylene glycol, glycerol and benzyl alcohol.

[0084] In the preparation method of the catalyst, the titanium dioxide carrier and the surfactant can be dispersed in the reducing agent by any known means, such as stirring or ultrasonic dispersion.

[0085] In the method for preparing the catalyst, the iridium metal precursor is preferably chloroiridic acid.

[0086] In the preparation method of the catalyst, the reaction temperature is generally 150° C. to 180° C., and the reaction time is generally 3 h to 8 h.

[0087] In the preparation method of the catalyst, the catalyst can be separated by conventional means, such as centrifugal separation.

[0088] In the catalyst preparation method, the separated catalyst may be subjected to appropriate post-treatment, such as washing, drying, etc. The washing may be performed using a mixed solvent of water and ethanol until the pH is neutral.

[0089] The present invention also provides a supported iridium catalyst prepared by the above method.

[0090] (3) Supported iridium catalyst

[0091] The invention provides a supported iridium catalyst, comprising a titanium dioxide carrier and metallic iridium supported on the carrier; an XRD spectrum of the catalyst has characteristic peaks of metallic iridium but no characteristic peaks of titanium dioxide.

[0092] In the XRD spectrum of the catalyst, there is only the characteristic peak of metallic iridium.

[0093] Preferably, the catalyst consists of titanium dioxide and metallic iridium.

[0094] In the catalyst, based on the mass of the catalyst, the mass fraction of iridium is 50% to 60%, and the mass fraction of titanium is 24% to 30%. In addition to iridium and titanium, the rest of the catalyst is oxygen or essentially oxygen.

[0095] The average particle size of the metal iridium in the catalyst is 2 nm to 3 nm. The measurement method is as follows: in a TEM test, 50 metal iridium particles are randomly counted, the distance between the two farthest points on the particle edge is taken as the particle size, and the average value is taken as the average particle size of the metal iridium.

[0096] In the TEM image of the catalyst, lattice fringes of titanium dioxide can be seen.

[0097] The Ir 4f In the XPS spectrum, there are two characteristic peaks at 60.7±0.1eV and 63.7±0.1eV, respectively.

[0098] (IV) Application of supported iridium catalysts

[0099] The present invention provides the use of the above catalyst as an oxygen evolution electrocatalyst in electrochemistry.

[0100] A proton exchange membrane water electrolyzer comprising a proton exchange membrane, a cathode catalyst layer, an anode catalyst layer, a cathode diffusion layer and an anode diffusion layer, wherein the anode catalyst layer uses the catalyst of any one of the preceding.

[0101] A method for electrolyzing water to produce hydrogen gas, wherein the catalyst of any one of the preceding or the proton exchange membrane water electrolyzer of the preceding is used.

[0102] The application will be described in detail below with specific examples. The following examples will help those skilled in the art to further understand the application, but do not limit the application in any form.

[0103] Reagents, instruments and tests

[0104] The raw materials used in the examples were obtained by commercial channels, and were all analytical pure unless otherwise specified. Among them, the chloroiridic acid raw material was in liquid form, and the mass fraction of iridium was 35%. For the convenience of taking, a solution with a concentration of 0.182 mol / L was prepared for use, and a solution with a higher concentration can also be prepared for use.

[0105] Instrument, method and condition of TEM analysis: The high-resolution transmission electron microscope (HRTEM) used in the application is JEM-2100 (HRTEM) (Japan Electron Corporation), and the test condition of high-resolution transmission electron microscope is that the acceleration voltage is 200 kV.

[0106] Instrument, method and condition of XPS analysis: The application detects the elements on the surface of the material by X-ray photoelectron spectroscopy analyzer (XPS). The X-ray photoelectron spectroscopy analyzer used is ESCALab220i-XL type ray electron spectrometer produced by VG Scientifc Company and equipped with AvantageV5.926 software, and the X-ray photoelectron spectroscopy analysis test condition is that the excitation source is monochromatic A1Kα X-ray, the power is 330 W, and the base vacuum during analysis and test is 3×10 -9 mbar. In addition, the electron binding energy is corrected by the C1s peak of elemental carbon (284.3 eV).

[0107] Instrument, method and condition of XRD analysis: X-ray diffraction analysis (XRD) is carried out on X-ray diffractometer of XRD-6000 of Japan Shimadzu, and the test condition includes: tube voltage 40 kV, tube current 40 mA, Cu target Kα radiation, 2θ scanning range 5° to 80°.

[0108] BET analysis instruments, methods, and conditions: BET specific surface area was determined using an ASAP2420 physical adsorption instrument from Micromeritics Instruments. The test conditions included the following: sample pretreatment: a certain amount of sample was weighed and placed into a sample tube that had been previously tested with a blank. The tube was then placed in a degassing unit, evacuated, and degassed for 6 hours at a furnace temperature of 300°C and a vacuum of less than 1.33 Pa. The sample was then measured: the pre-treated sample tube was placed into the measurement unit, and the Dewar flask was filled with liquid nitrogen. The adsorption isotherm was determined using the static volumetric method, the pore size distribution was calculated using the BJH method, and the specific surface area was calculated using the BET formula.

[0109] The electrochemical workstation was a PARSTAT 3000A-DX, and the rotating disk electrode was a 636A. A three-electrode system was used, with a saturated calomel electrode as the reference electrode, a platinum sheet as the counter electrode, and a glassy carbon electrode as the working electrode. The acidic electrolyte used was a 0.5 M H₂SO₄ solution. The catalyst to be tested was ultrasonically dispersed in a mixture of isopropanol, water, and Nafion, then dripped onto the surface of the glassy carbon electrode and allowed to dry naturally to obtain the working electrode. The catalyst loading was 0.38 mg·cm⁻¹. -2 The test temperature was 25°C. Oxygen was passed through the solution for 30 minutes before testing to saturate the solution with oxygen. The rotation speed was 2500 rpm. The linear polarization curve scan range was 1.2 V to 1.5 V (vs RHE) at a scan rate of 5 mV / s. The stability test scan range was 1.26 V to 1.56 V (vs RHE) at a scan rate of 50 mV / s.

[0110] In the embodiment, CTAC is cetyltrimethylammonium chloride.

[0111] Preparation Example 1

[0112] This preparation example is used to illustrate the preparation of the titanium dioxide carrier of the present invention.

[0113] 1) Dissolve 3.6 g (15 mmol) of titanium sulfate and 4.3 g (22.5 mmol) of citric acid in 50 mL of water and stir at 90° C. for 0.5 hour to fully mix the titanium sulfate and citric acid;

[0114] 2) adding Na2CO3 solution to adjust the pH of the solution to 8-9, and stirring at 90°C for 3.5 hours;

[0115] 3) Remove water by rotary evaporation at 70°C and dry the solid in an oven at 100°C overnight;

[0116] 4) Take out the dried solid, grind it, spread it flat on a porcelain boat, and heat it to 500°C at a rate of 2°C / min in air atmosphere and hold it for 2 h;

[0117] 5) Cool to room temperature, add a certain amount of deionized water, ultrasonically wash, centrifuge (10000 rpm, 10 min), and then wash with a 1:1 mixed solvent of ethanol and water until the pH test paper detects neutrality. Place in a vacuum drying oven at 25°C overnight, and grind to obtain titanium dioxide support A.

[0118] from Figure 1 It can be seen that the titanium dioxide carrier of this preparation example does not have a sharp strong diffraction peak, and has a weak crystalline structure, which is different from the anatase crystal structure of commercial nano titanium dioxide (see Figure 8 ).from Figure 2 It can be seen that the titanium dioxide carrier of this preparation example has weak crystallinity, and most of it is a cotton-like amorphous structure, and a small amount of weak lattice fringes can be observed. Figure 4 Medium O 1s The XPS spectrum shows the presence of oxygen vacancies, O 1s It can be divided into three diffraction peaks, with three characteristic peaks at 532.8±0.1eV, 531.4±0.1eV and 529.6±0.1eV respectively, and the peak area ratio of the three is 6.5 / 22.7 / 70.8; different from the O 1s XPS spectra (see Figure 9 ), the peak area ratio of the three is 8.2 / 17.8 / 74.0. Figure 5 Medium Ti 2p3 / 2XPS spectrum shows that titanium is +4 valence. Figure 10 As shown in the figure, the resistivity of the titanium dioxide carrier in this preparation example is lower than that of commercial nano titanium dioxide.

[0119] The specific surface area of ​​the titanium dioxide carrier in this preparation example is 183.5 m 2 / g.

[0120] Preparation Example 2

[0121] This preparation example is used to illustrate the preparation of the titanium dioxide carrier of the present invention.

[0122] 1) Dissolve 3.6 g (15 mmol) of titanium sulfate and 2.8 g (15 mmol) of citric acid in 50 mL of water and stir at 90° C. for 0.5 hour to fully mix the titanium sulfate and citric acid;

[0123] 2) adding NaOH solution to adjust the pH of the solution to 8-9, and stirring at 90°C for 3.5 hours;

[0124] 3) Remove water by rotary evaporation at 70°C and dry the solid in an oven at 100°C overnight;

[0125] 4) Take out the dried solid, grind it, spread it flat on a porcelain boat, and heat it to 600°C at a rate of 2°C / min in air atmosphere and hold it for 2 h;

[0126] 5) Cool to room temperature, add a certain amount of deionized water, ultrasonically wash, centrifuge (10000 rpm, 10 min), and then wash with a 1:1 mixed solvent of ethanol and water until the pH test paper detects neutrality. Place in a vacuum drying oven at 25°C overnight, and grind to obtain titanium dioxide support B.

[0127] from Figure 6 It can be seen that the titanium dioxide carrier of this preparation example does not have a sharp strong diffraction peak, and has a weak crystalline structure, which is different from the anatase crystal structure of commercial nano titanium dioxide (see Figure 8 ). The TEM spectrum of the titanium dioxide support in this preparation example is the same as Figure 2 The characteristics shown. The Ti of the titanium dioxide carrier in this preparation example 2p3 / 2 XPS spectra Figure 5 The resistivity of the titanium dioxide carrier in this preparation example is the same as Figure 10 Features shown.

[0128] The specific surface area of ​​the titanium dioxide carrier in this preparation example is 156.2 m 2 / g.

[0129] Preparation Example 3

[0130] This preparation example is used to illustrate the preparation of the titanium dioxide carrier of the present invention.

[0131] 1) Dissolve 3.6 g (15 mmol) of titanium sulfate and 5.6 g (30 mmol) of citric acid in 50 mL of water and stir at 90° C. for 0.5 hour to fully mix the titanium sulfate and citric acid;

[0132] 2) adding NaOH solution to adjust the pH of the solution to 9-10, and stirring at 90°C for 3 hours;

[0133] 3) Remove water by rotary evaporation at 70°C and dry the solid in an oven at 100°C overnight;

[0134] 4) Take out the dried solid, grind it, spread it flat on a porcelain boat, and heat it to 500°C at a rate of 2°C / min in air atmosphere and hold it for 2 h;

[0135] 5) Cool to room temperature, add a certain amount of deionized water, ultrasonically wash, centrifuge (10000 rpm, 10 min), and then wash with a 1:1 mixed solvent of ethanol and water until the pH test paper detects neutrality. Place in a vacuum drying oven at 25°C overnight, and grind to obtain titanium dioxide support C.

[0136] from Figure 7 It can be seen that the titanium dioxide carrier of this preparation example does not have a sharp strong diffraction peak, and has a weak crystalline structure, which is different from the anatase crystal structure of commercial nano titanium dioxide (see Figure 8 ). The TEM spectrum of the titanium dioxide support in this preparation example is the same as Figure 2 The characteristics shown. The Ti of the titanium dioxide carrier in this preparation example 2p3 / 2 XPS spectra Figure 5 The resistivity of the titanium dioxide carrier in this preparation example is the same as Figure 10 Features shown.

[0137] Preparation Example 4

[0138] This preparation example is used to illustrate the preparation of the catalyst of the present invention.

[0139] 1) Disperse 40 mg of carrier A and 1.13 g of CTAC in 80 mL of propylene glycol and stir for 1 h to ensure uniform dispersion.

[0140] 2) Add 1.715 mL (0.31 mmol) of aqueous chloroiridic acid solution, stir for 2 h, and then reflux in an oil bath at 160°C for 3 h;

[0141] 3) Cooling to room temperature, centrifuging (10,000 rpm, 5 min) to obtain a solid catalyst, washing with a 1:1 mixed solvent of ethanol and water and centrifuging repeatedly until the pH test paper shows neutral, drying in a vacuum drying oven at 25° C. overnight, and grinding to obtain Catalyst A of the present invention.

[0142] from Figure 11 It can be seen that the XRD spectrum of the catalyst in this preparation example only has the characteristic peak of metallic iridium. Figure 12 It can be seen that in the catalyst of this preparation example, the iridium particles are uniformly dispersed on the carrier, the size of the iridium particles is 2nm to 3nm, and a small amount of weak lattice fringes can be observed on the carrier part. Figure 13 Medium Ir 4f The XPS spectrum shows that there are two characteristic peaks at 60.7±0.1ev and 63.7±0.1ev, respectively. Figure 14 The comparison of the anodic polarization curves of the catalysts shows that the acidic OER performance of the catalyst prepared in this example is better than that of the commercial anatase-type titanium dioxide-loaded iridium catalyst and the commercial iridium dioxide catalyst. 2 When , the decomposition voltage is 1.438V, and the corresponding anode overpotential is 208mV. Figure 15As shown, after the catalyst of this preparation example was circulated for 30,000 cycles in the potential range of 1.26V to 1.56V, its overpotential only increased by 14mV, while the overpotential of the commercial iridium dioxide catalyst increased by 23mV after 10,000 cycles, indicating that the present invention significantly improves the stability of the catalyst.

[0143] In the catalyst of this preparation example, the mass fraction of iridium element is 58%, and the mass fraction of titanium element is 34%.

[0144] Preparation Example 5

[0145] This preparation example is used to illustrate the preparation of the catalyst of the present invention.

[0146] 1) Disperse 40 mg of carrier B and 1.13 g of CTAC in 80 mL of propylene glycol and stir for 1 h to ensure uniform dispersion;

[0147] 2) Add 1.715 mL (0.31 mmol) of aqueous chloroiridic acid solution, stir for 2 h, and then reflux in an oil bath at 160 °C for 5 h;

[0148] 3) Cooling to room temperature, centrifuging (10,000 rpm, 5 min) to obtain a solid catalyst, washing with a 1:1 mixed solvent of ethanol and water and centrifuging repeatedly until the pH test paper shows neutral, drying in a vacuum drying oven at 25° C. overnight, and grinding to obtain Catalyst B of the present invention.

[0149] The XRD pattern of the catalyst in this preparation example is as follows Figure 11 The TEM spectrum of the catalyst in this preparation example has the following characteristics: Figure 12 The characteristics shown. The Ir 4f XPS spectra have Figure 13 Features shown.

[0150] Preparation Example 6

[0151] This preparation example is used to illustrate the preparation of the catalyst of the present invention.

[0152] 1) Disperse 40 mg of carrier C and 1.13 g of CTAC in 80 mL of benzyl alcohol and stir for 1 h to ensure uniform dispersion;

[0153] 2) Add 1.715 mL (0.31 mmol) of aqueous chloroiridic acid solution, stir for 2 h, and then reflux in an oil bath at 150 °C for 5 h;

[0154] 3) Cooling to room temperature, centrifuging (10,000 rpm, 5 min) to obtain a solid catalyst, washing with a 1:1 mixed solvent of ethanol and water and centrifuging repeatedly until the pH test paper shows neutral, drying in a vacuum drying oven at 25° C. overnight, and grinding to obtain Catalyst C of the present invention.

[0155] The XRD pattern of the catalyst in this preparation example is as follows Figure 11 The TEM spectrum of the catalyst in this preparation example has the following characteristics: Figure 12 The characteristics shown. The Ir 4f XPS spectra have Figure 13 Features shown.

[0156] Preparation Example 7

[0157] This preparation example is used to illustrate the preparation of the catalyst of the present invention.

[0158] 1) Disperse 40 mg of carrier A and 1.13 g of polyvinyl pyrrolidone in 80 mL of propylene glycol and stir for 1 h to ensure uniform dispersion.

[0159] 2) Add 1.715 mL (0.31 mmol) of aqueous chloroiridic acid solution, stir for 2 h, and then reflux in an oil bath at 160°C for 3 h;

[0160] 3) Cooling to room temperature, centrifuging (10,000 rpm, 5 min) to obtain a solid catalyst, washing with a 1:1 mixed solvent of ethanol and water and centrifuging repeatedly until the pH test paper indicates neutrality, drying in a vacuum drying oven at 25° C. overnight, and grinding to obtain Catalyst D of the present invention.

[0161] The XRD pattern of the catalyst in this preparation example is as follows Figure 11 Features shown.

[0162] Comparative Example 1

[0163] 1) Disperse 40 mg of commercial anatase titanium dioxide and 1.13 g of CTAC in 80 mL of propylene glycol and stir for 1 h to ensure uniform dispersion.

[0164] 2) Add 1.715 mL (0.31 mmol) of aqueous chloroiridic acid solution, stir for 2 h, and then reflux in an oil bath at 160°C for 3 h;

[0165] 3) Cool to room temperature, centrifuge (10,000 rpm, 5 min) to obtain a solid catalyst, wash with a 1:1 mixed solvent of ethanol and water and centrifuge repeatedly until the pH test paper shows neutral, dry in a vacuum drying oven at 25°C overnight, and grind to obtain a comparative catalyst.

[0166] Table 1 Comparison of OER performance of catalysts

[0167]

[0168]

Claims

1. A method for preparing a supported iridium catalyst, comprising: (1) dispersing a titanium dioxide carrier and a surfactant in a liquid reducing agent to obtain a suspension; (2) adding an iridium metal precursor to the suspension, reacting at a temperature above the reduction temperature, and obtaining a supported iridium catalyst by separation after the reaction is completed; The preparation method of the titanium dioxide carrier comprises: dissolving a polybasic organic carboxylic acid and / or a polybasic organic carboxylate and a titanium source in water; reacting the solution at a pH of 7 to 10; removing the solvent to obtain a solid; and calcining the solid to obtain the titanium dioxide carrier; the calcination is carried out in an oxygen-containing atmosphere at a temperature of 400° C. to 600° C. for 2 to 6 hours. The titanium dioxide carrier has an X-ray diffraction pattern as shown in the following table: I0 is the intensity of the strongest characteristic peak, I is the intensity of each other characteristic peak, according to 100×(I / I0), Vs=80~100, m=25~40, w=0.01~25.

2. The method for preparing a supported iridium catalyst according to claim 1, wherein The titanium dioxide support O 1s In the XPS spectrum, there are three characteristic peaks at 532.8±0.1eV, 531.4±0.1eV and 529.6±0.1eV respectively; among them, the peak area of ​​the characteristic peak at 531.4±0.1eV accounts for 20% to 25% of the total peak area of ​​the three.

3. The method for preparing a supported iridium catalyst according to claim 1, wherein The surfactant is a quaternary ammonium salt containing at least one C12-C18 alkyl group.

4. The method for preparing a supported iridium catalyst according to claim 1, wherein The liquid reducing agent is one or more of propylene glycol, glycerol and benzyl alcohol.

5. A catalyst, characterized in that The catalyst is prepared by the preparation method of the supported iridium catalyst according to any one of claims 1 to 4.

6. Use of the catalyst according to claim 5 as an oxygen evolution electrocatalyst in electrochemistry.

7. A proton exchange membrane water electrolyzer comprising a proton exchange membrane, a cathode catalyst layer, an anode catalyst layer, a cathode diffusion layer and an anode diffusion layer, wherein: The catalyst according to claim 5 is used in the anode catalyst layer.

8. A method for producing hydrogen by electrolysis of water, wherein: The catalyst according to claim 5 or the proton exchange membrane water electrolyzer according to claim 7 is used.

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