Iridium-containing supported catalyst, preparation method and application thereof, and proton exchange membrane water electrolyser

Abstract

The invention relates to an iridium-containing supported catalyst, a preparation method and application thereof, and a proton exchange membrane water electrolyser, the catalyst comprises a carrier and an active component supported on the carrier, the carrier is one of titanium dioxide, niobium pentoxide and tantalum pentoxide, and the active component is an iridium oxide; a characteristic peak of the carrier and an amorphous peak packet of the iridium oxide exist on an XRD (X-Ray Diffraction) spectrogram of the catalyst. Compared with a commercial iridium oxide catalyst, the catalyst disclosed by the invention has higher catalytic activity, the use amount of noble metal is remarkably reduced, the cost is remarkably reduced, and the catalyst has relatively high use value.

Description

Technical Field

[0001] The present disclosure relates to the field of catalysts for hydrogen production by water electrolysis, and in particular to an iridium-containing supported catalyst, a preparation method and application thereof, and a proton exchange membrane water electrolyzer. Background Art

[0002] Compared with alkaline water electrolysis technology, proton exchange membrane water electrolysis hydrogen production technology has the advantages of fast response speed, high current density, wide working load range, and high hydrogen purity. In particular, it has unparalleled advantages in the field of using renewable energy to generate electricity and then electrolyze water to produce hydrogen. It is the main way to obtain green hydrogen in the future. Anode catalyst is one of the key materials for proton exchange membrane water electrolysis hydrogen production and is the main rate-controlling step for PEM water electrolysis hydrogen production. At present, commercial PEM water electrolysis devices basically use iridium oxide or iridium black catalysts. The price of precious metal iridium is expensive (~1,000 yuan / g), and the dosage reaches 1-2 mg / cm 2 Therefore, reducing the amount of iridium used at the anode is one of the important breakthroughs for the large-scale application of PEM water electrolysis. Loading catalytically active iridium on a corrosion-resistant carrier is a common strategy. On the one hand, the electrochemical intrinsic activity of the catalyst is improved through the strong metal-carrier interaction. On the other hand, the dispersion of the metal on the carrier surface can effectively improve the utilization rate of the active component. The form of the metallic iridium loaded and on the carrier has a great influence on the activity and stability of the catalyst. Currently, there are two mainstream forms of existence: one is mainly composed of elemental iridium and is prepared by the reduction method, and the other is mainly composed of iridium dioxide and is prepared by the molten salt method. The former has high activity and the latter has good stability. Summary of the Invention

[0003] The purpose of the present disclosure is to provide an iridium-containing supported catalyst, a preparation method and application thereof, and a proton exchange membrane water electrolyzer. When the catalyst is used as an anode catalyst for proton exchange membrane water electrolysis to produce hydrogen, it has higher catalytic activity than commercial iridium oxide catalysts, and the amount of precious metal used is significantly reduced, the cost is significantly reduced, and it has great use value.

[0004] In order to achieve the above-mentioned object, the present disclosure provides, in a first aspect, an iridium-containing supported catalyst, the catalyst comprising a carrier and an active component supported on the carrier, the carrier being one of titanium dioxide, niobium pentoxide and tantalum pentoxide, and the active component being iridium oxide;

[0005] The XRD spectrum of the catalyst contains characteristic peaks of the carrier and an amorphous peak package of iridium oxide.

[0006] Optionally, the XRD spectrum of the catalyst does not have the crystal plane diffraction peak of the iridium oxide, and the amorphous peak package only exists between 30° and 40°.

[0007] Optionally, the XRD spectrum of the catalyst shows crystal plane diffraction peaks of the carrier at 22-33° and 39-49°, respectively.

[0008] Optionally, the Ir 4f characteristic peaks of the XPS spectrum of the catalyst include the Ir(IV) characteristic peaks, and do not include the characteristic peaks of elemental Ir and Ir(III).

[0009] Optionally, based on the weight of the catalyst, the weight content of Ir is 40 to 60 wt%.

[0010] Optionally, the particle size of the active component in the catalyst is 2 to 6 nm, and the specific surface area of ​​the catalyst is 80 to 120 m 2 / g.

[0011] A second aspect of the present disclosure provides a method for preparing an iridium-containing supported catalyst, the method comprising the following steps:

[0012] S1, mixing an iridium source, a carrier, a complexing agent and water, adjusting the pH of the mixture to 3-6, and reacting to obtain a reaction mass, wherein the complexing agent is selected from one or more of C4-C8 organic polyacids and soluble salts thereof;

[0013] S2, separating water from the reaction material to obtain a supported catalyst precursor;

[0014] S3, calcining the supported catalyst precursor in an oxygen-containing atmosphere;

[0015] The carrier is selected from one of crystalline titanium dioxide, niobium pentoxide and tantalum pentoxide.

[0016] Optionally, the iridium source is selected from one or more of chloroiridic acid and chloroiridic acid alkali metal salts; preferably, the chloroiridic acid alkali metal salt is selected from one or both of potassium chloroiridate and sodium chloroiridate;

[0017] The particle size of the carrier is less than 100 nm;

[0018] The complexing agent is selected from one or more of citric acid, tartaric acid, malic acid, succinic acid, sodium citrate, sodium tartrate, sodium malate and sodium succinate.

[0019] Optionally, in step S1, the molar ratio of the complexing agent to the iridium source calculated as iridium is 1 to 2:1, preferably 1.4 to 1.7:1.

[0020] Optionally, in step S1, the reaction conditions include: temperature of 50-80°C, preferably 60-70°C; reaction time of 0.5-4h, preferably 1-2h;

[0021] Preferably, in step S1, the pH of the mixed material is 4 to 5;

[0022] Optionally, a pH regulator is added to adjust the pH. Optionally, the pH regulator is selected from one or more of sodium carbonate, sodium bicarbonate, sodium hydroxide and ammonia water.

[0023] Optionally, in step S3, the calcination conditions include: a calcination temperature of 400-500° C., preferably 420-450° C.; a calcination time of 1-3 hours, preferably 2-2.5 hours; and an oxygen content of 20-80% by volume in the oxygen-containing atmosphere.

[0024] The third aspect of the present disclosure provides an iridium-containing supported catalyst prepared by the method described in the second aspect of the present disclosure.

[0025] The fourth aspect of the present disclosure provides use of the catalyst described in the first aspect and the third aspect of the present disclosure in producing hydrogen by electrolysis of water.

[0026] The fifth aspect of the present disclosure provides 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 adopts the catalyst described in the first aspect and the third aspect of the present disclosure.

[0027] Through the above technical solution, the present disclosure provides an iridium-containing supported catalyst, a preparation method, and an application thereof. The catalyst includes a carrier and an active component supported on the carrier, wherein the carrier is one of titanium dioxide, niobium pentoxide, and tantalum pentoxide, and the active component is an amorphous oxide of iridium. The XRD spectrum shows characteristic peaks of the carrier and an amorphous peak package of the iridium oxide, but no crystalline diffraction peak of the iridium oxide is present. The iridium oxide is uniformly distributed on the surface of the carrier and has a small particle size. When used as an anode catalyst for hydrogen production by proton exchange membrane water electrolysis, the catalyst has higher catalytic activity than commercial iridium oxide catalysts, and the amount of precious metal used is significantly reduced, the cost is significantly reduced, and the catalyst has great use value.

[0028] In addition, during the preparation process, the present invention adopts a complexing agent to mix with the iridium source and the carrier, and selects a suitable pH according to the isoelectric point of the carrier to enhance the interaction between the soluble iridium precursor and the carrier, thereby improving the dispersion of the metal on the carrier surface; and the present invention adopts C4-C8 organic polyacids and soluble salts thereof as complexing agents to avoid precipitation of the solution; the reaction process does not use highly corrosive solvents such as hydrochloric acid, and the preparation method is simple to operate and the conditions are mild.

[0029] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following detailed description, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0031] Figure 1 is the XRD pattern of the product obtained in Example 1 of the present disclosure.

[0032] Figure 2 is the Ir 4f XPS spectrum of the product obtained in Example 1 of the present disclosure. DETAILED DESCRIPTION

[0033] The following describes the specific embodiments of the present disclosure in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure and are not intended to limit the present disclosure.

[0034] In a first aspect, the present disclosure provides an iridium-containing supported catalyst, comprising a carrier and an active component supported on the carrier, wherein the carrier is one of titanium dioxide, niobium pentoxide and tantalum pentoxide, and the active component is iridium oxide;

[0035] The XRD spectrum of the catalyst contains characteristic peaks of the carrier and an amorphous peak package of iridium oxide.

[0036] The iridium-containing supported catalyst provided by the present disclosure includes a crystalline carrier and an active component supported on the carrier, wherein the active component is an amorphous oxide of iridium; the iridium oxide is uniformly distributed on the surface of the carrier and has a small particle size. When used as an anode catalyst for proton exchange membrane water electrolysis to produce hydrogen, it has higher catalytic activity than commercial iridium oxide catalysts, and the amount of precious metal used is significantly reduced, the cost is significantly reduced, and the catalyst has great use value.

[0037] In the present disclosure, "peak envelope" in the XRD spectrum refers to other forms of protrusions that appear in the XRD spectrum in addition to the obvious and sharp characteristic peaks conventionally recognized by those skilled in the art. "Peak envelope" generally has the characteristics of low intensity and large width.

[0038] According to one embodiment of the present disclosure, the XRD spectrum of the catalyst does not have the crystal plane diffraction peak of the iridium oxide, and the amorphous peak package is only present between 30° and 40°. In the present disclosure, in the XRD spectrum of the catalyst, except for the characteristic peak of the support and the amorphous peak package between 30° and 40°, no other characteristic peaks are present.

[0039] According to one embodiment of the present disclosure, the XRD spectrum of the catalyst shows crystal plane diffraction peaks of the carrier at 22-33° and 39-49°, respectively. In one embodiment, the carrier of the catalyst is titanium dioxide, and the XRD spectrum of the catalyst shows crystal plane diffraction peaks of titanium dioxide at 24-26° and 47-49°. In one embodiment, the carrier of the catalyst is niobium pentoxide, and the XRD spectrum of the catalyst shows crystal plane diffraction peaks of niobium pentoxide at 22-24°, 31-33° and 45-47°. In one embodiment, the carrier of the catalyst is tantalum pentoxide, and the XRD spectrum of the catalyst shows crystal plane diffraction peaks of tantalum pentoxide at 29-31° and 39-41°.

[0040] According to one embodiment of the present disclosure, the Ir 4f characteristic peaks of the XPS spectrum of the catalyst include the Ir(IV) characteristic peaks, and do not include the characteristic peaks of elemental Ir and Ir(III).

[0041] According to one embodiment of the present disclosure, based on the weight of the catalyst, the weight content of Ir is 40 to 60 wt%, preferably 50 to 55 wt%. The weight content of Ir can be measured by ICP.

[0042] According to one embodiment of the present disclosure, the particle size of the active component in the catalyst is 2 to 6 nm, preferably 3 to 4 nm; the specific surface area of ​​the catalyst is 80 to 120 m 2 / g, preferably 100 to 110 m 2 In the present disclosure, the particle size of the active component refers to the particle size of the active component measured by transmission electron microscopy. For example, "the particle size of the active component is 2 to 10 nm" means that the particle size of each active component particle in the transmission electron microscope spectrum is within the range of 2 to 10 nm.

[0043] A second aspect of the present disclosure provides a method for preparing an iridium-containing supported catalyst, the method comprising the following steps:

[0044] S1, mixing an iridium source, a carrier, a complexing agent and water, adjusting the pH of the mixture to 3-6, and reacting to obtain a reaction mass, wherein the complexing agent is selected from one or more of C4-C8 organic polyacids and soluble salts thereof;

[0045] S2, separating water from the reaction material to obtain a supported catalyst precursor;

[0046] S3, calcining the supported catalyst precursor in an oxygen-containing atmosphere;

[0047] The carrier is selected from one of crystalline titanium dioxide, niobium pentoxide and tantalum pentoxide.

[0048] During the preparation process of the method disclosed herein, a complexing agent, an iridium source and a specific carrier are mixed, and a suitable pH is selected according to the isoelectric point of the carrier. This can enhance the interaction between the soluble iridium precursor and the specific carrier, improve the dispersion of the metal on the carrier surface during calcination, and make the metal iridium oxidized more fully to form a supported catalyst with surface-dispersed amorphous iridium oxide; and the present disclosure uses C4-C8 organic polyacids and their soluble salts as complexing agents to avoid precipitation in the solution. The reaction process does not use highly corrosive solvents such as hydrochloric acid, and the preparation method is simple to operate and the conditions are mild. In the iridium-containing supported catalyst disclosed herein, the active component iridium oxide is in an amorphous state and the iridium is in a tetravalent state. The active component is exposed on the surface of the catalyst, which is conducive to the catalyst having a higher mass specific activity, a lower overpotential, and a higher oxygen evolution activity.

[0049] According to one embodiment of the present disclosure, the iridium source is selected from one or more of chloroiridic acid and alkali metal chloroiridates; preferably, the alkali metal chloroiridate is selected from one or both of potassium chloroiridate and sodium chloroiridate; the chloroiridic acid may or may not contain water of crystallization, generally containing water of crystallization (e.g., a compound represented by the formula H2IrCl6·6H2O or (NH4)2IrCl6·6H2O). The particle size of the carrier may be less than 100 nm; the complexing agent is selected from one or more of citric acid, tartaric acid, malic acid, succinic acid, sodium citrate, sodium tartrate, sodium malate, and sodium succinate, preferably one or more of citric acid, sodium citrate, malic acid, and sodium malate.

[0050] According to one embodiment of the present disclosure, in step S1, the molar ratio of the complexing agent to the iridium source is 1 to 2: 1, preferably 1.4 to 1.7: 1. The above embodiment is conducive to the catalyst having a lower overpotential, a higher mass specific activity, and a higher oxygen evolution activity.

[0051] According to one embodiment of the present disclosure, in step S1, the reaction conditions include: a temperature of 50 to 80°C, preferably 60 to 70°C; a reaction time of 0.5 to 4 hours, preferably 1 to 2 hours; preferably, in step S1, the pH of the mixture is 4 to 5; optionally, a pH adjuster is added to adjust the pH, optionally, the pH adjuster is selected from one or more of sodium carbonate, sodium bicarbonate, sodium hydroxide, and ammonia. The above embodiment is conducive to the catalyst having a lower overpotential, a higher mass specific activity, and a higher oxygen evolution activity.

[0052] According to one embodiment of the present disclosure, in step S3, the calcination conditions include: a calcination temperature of 400-500°C, preferably 420-450°C; a calcination time of 1-3 hours, preferably 2-2.5 hours; and an oxygen content of 20-80% by volume in the oxygen-containing atmosphere. In one embodiment, the oxygen-containing atmosphere can be air. This embodiment is conducive to the catalyst having a lower overpotential, a higher mass specific activity, and a higher oxygen evolution activity.

[0053] According to one embodiment of the present disclosure, the method further includes: washing the product obtained by the roasting treatment; the solvent used in the washing treatment is a mixed solution of alcohol and water, and the alcohol accounts for 10 to 95% by weight of the mass of the mixed solution, preferably 30 to 60% by weight; preferably, the alcohol is selected from one or more of methanol, ethanol, n-propanol and isopropanol.

[0054] According to one embodiment of the present disclosure, the method further comprises: a drying step after washing, and the drying temperature may be 50-70°C.

[0055] The third aspect of the present disclosure provides an iridium-containing supported catalyst prepared by the method described in the second aspect of the disclosure.

[0056] In a fourth aspect, the present disclosure provides a use of the catalyst described in the first aspect and the third aspect of the present disclosure in producing hydrogen by electrolysis of water.

[0057] The fifth aspect of the present disclosure provides 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 adopts the catalyst described in the first aspect and the third aspect of the present disclosure.

[0058] The present disclosure is described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present disclosure, but are not intended to limit the present disclosure in any form.

[0059] Reagents, Instruments and Tests

[0060] All raw materials used in the examples were commercially available and, unless otherwise specified, were of analytical grade. Titanium dioxide powder was purchased from Inotech under the designation A58022; niobium pentoxide powder was purchased from Inotech under the designation A81394; and tantalum pentoxide powder was purchased from Inotech under the designation A54445. Chloroiridic acid or an alkali metal chloroiridic acid salt was prepared as a 0.182 mol / L aqueous solution, although higher concentrations were possible. All other reagents were of analytical grade.

[0061] TEM analysis instruments, methods and conditions: The high-resolution transmission electron microscope (HRTEM) used in the present invention is a JEM-2100 (HRTEM) (JEOL Ltd.), and the high-resolution transmission electron microscope test conditions are: an accelerating voltage of 200 kV.

[0062] The model of the X-ray fluorescence spectrometer (XRF) is a Rigaku 3013 X-ray fluorescence spectrometer. The X-ray fluorescence spectrometry analysis test conditions are: a scanning time of 100 s, and an air atmosphere.

[0063] The present invention uses X-ray photoelectron spectroscopy (XPS) to detect the elements on the surface of the material. The X-ray photoelectron spectrometer used is an ESCALab220i-XL X-ray spectrometer equipped with Avantage V5.926 software produced by VG Scientific. The X-ray photoelectron spectroscopy analysis test conditions are as follows: the excitation source is monochromatic A1Kα X-ray with a power of 330W, and the basic vacuum during the analysis test is 3×10 -9 In addition, the electron binding energy was calibrated using the C1s peak (284.3 eV) of elemental carbon.

[0064] BET test method: In the present disclosure, the pore structure properties of the samples were measured by a Quantachrome AS-6B analyzer, and the specific surface area of ​​the catalyst was obtained by the Brunauer-Emmett-Taller (BET) method.

[0065] X-ray diffraction analysis (XRD) was performed on a Shimadzu XRD-6000 X-ray diffractometer (Japan) under the following test conditions: tube voltage 40 kV, tube current 40 mA, Cu target Kα radiation, and 2θ scanning range 5° to 80°.

[0066] The electrochemical workstation model was PARSTAT3000A-DX, and the rotating disk electrode model was 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 dried naturally to obtain the working electrode. The catalyst loading was 0.38 mg / cm3. -2 The test temperature was 25°C. Oxygen was introduced for 30 minutes before testing to saturate the solution. The rotation speed was 2500 rpm. The linear polarization curve scan range was 1.2-1.5 V (vs RHE) at a scan rate of 5 mV / s. The stability test scan range was 1.26-1.56 V (vs RHE) at a scan rate of 50 mV / s, and the number of scans was 10,000.

[0067] Example 1

[0068] (1) Take 10 mL (0.35 g, 1.8 mmol) of chloroiridic acid aqueous solution, weigh 0.22 g of titanium dioxide powder, and 0.52 g of citric acid (complexing agent, 2.7 mmol), stir and mix at room temperature, adjust the pH of the solution to between 4 and 5, and react at 70°C for 1 hour; wherein the molar ratio of the complexing agent to the iridium source is 1.5:1;

[0069] (2) After cooling, spin-dry at 70°C and dry in an oven at 120°C for 8 h;

[0070] (3) After the solid is removed and cooled, it is ground and placed flat on a porcelain boat. In an air atmosphere, the temperature is increased to 420°C at a heating rate of 2°C / min and maintained for 2 h.

[0071] (4) Cool to room temperature, add a certain amount of deionized water, ultrasonically wash, centrifuge (10000 rpm, 10 min), then wash with a 1:1 mixed solvent of ethanol and water, centrifuge three times (pH test paper detection is neutral), place the centrifuge tube with the catalyst in a forced air drying oven (60 ° C) and dry for 12 h to finally obtain the catalyst, which is recorded as CAT-1.

[0072] like Figure 1 As shown in the XRD pattern of CAT-1, there are crystalline phase peaks of the carrier titanium dioxide at 2θ of 25° and 48°, and only a weak amorphous peak package appears around 30-40°, and no crystalline phase peaks of elemental iridium and iridium dioxide appear. Figure 2 As shown, iridium exists mainly in the form of Ir(IV).

[0073] Example 2

[0074] (1) 10 mL (0.35 g, 1.8 mmol) of chloroiridic acid aqueous solution was taken, 0.22 g of niobium pentoxide powder and 0.52 g (2.7 mmol) of citric acid were weighed, and after stirring and mixing at room temperature, the pH of the solution was adjusted to between 4 and 5, and the reaction was carried out at 70°C for 1 hour; wherein the molar ratio of the complexing agent to the iridium source was 1.5:1;

[0075] (2) After cooling, spin-dry at 70°C and dry in an oven at 120°C for 8 h;

[0076] (3) After the catalyst is removed and cooled, it is ground and placed flat on a porcelain boat. In an air atmosphere, the temperature is increased to 420°C at a heating rate of 2°C / min and maintained for 2 h.

[0077] (4) Cool to room temperature, add a certain amount of deionized water, ultrasonically wash, centrifuge (10000 rpm, 10 min), then wash with a 1:1 mixed solvent of ethanol and water, centrifuge three times (pH test paper detection is neutral), place the centrifuge tube with the catalyst in a forced air drying oven (60 ° C) and dry for 12 h to finally obtain the catalyst, which is recorded as CAT-2.

[0078] Example 3

[0079] (1) Take 10 mL (0.35 g, 1.8 mmol) of chloroiridic acid aqueous solution, weigh 0.22 g of tantalum pentoxide powder, and 0.52 g (2.7 mmol) of citric acid, stir and mix at room temperature, and adjust the pH of the solution to between 4 and 5; react the solution at 70°C for 1 hour; wherein the molar ratio of the complexing agent to the iridium source is 1.5:1;

[0080] (2) After cooling, spin-dry at 70°C and dry in an oven at 120°C for 8 h;

[0081] (3) After the solid is removed and cooled, it is ground and placed flat on a porcelain boat. In an air atmosphere, the temperature is increased to 420°C at a heating rate of 2°C / min and maintained for 2 h.

[0082] (4) Cool to room temperature, add a certain amount of deionized water, ultrasonically wash, centrifuge (10000 rpm, 10 min), then wash with a 1:1 mixed solvent of ethanol and water, centrifuge three times (pH test paper detection is neutral), place the centrifuge tube with the catalyst in a forced air drying oven (60 ° C) and dry for 12 h to finally obtain the catalyst, which is recorded as CAT-3.

[0083] Example 4

[0084] The method of this embodiment is the same as that of Example 1, except that the amount of citric acid weighed in step (1) is different, and the molar ratio of the complexing agent to the iridium source is 1:1, as follows:

[0085] (1) Take 10 mL (0.35 g, 1.8 mmol) of chloroiridic acid aqueous solution, weigh 0.22 g of titanium dioxide powder, and 0.35 g of citric acid (complexing agent, 1.8 mmol), stir and mix at room temperature, adjust the pH of the solution to between 4 and 5, and react at 70°C for 1 hour; wherein the molar ratio of the complexing agent to the iridium source is 1:1;

[0086] (2) After cooling, spin-dry at 70°C and dry in an oven at 120°C for 8 h;

[0087] (3) After the solid is removed and cooled, it is ground and placed flat on a porcelain boat. In an air atmosphere, the temperature is increased to 420°C at a heating rate of 2°C / min and maintained for 2 h.

[0088] (4) Cool to room temperature, add a certain amount of deionized water, ultrasonically wash, centrifuge (10000 rpm, 10 min), then wash with a 1:1 mixed solvent of ethanol and water, centrifuge three times (pH test paper detection is neutral), place the centrifuge tube with the catalyst in a forced air drying oven (60 ° C) and dry for 12 h to finally obtain the catalyst, which is recorded as CAT-4.

[0089] Example 5

[0090] (1) Take 10 mL (0.35 g, 1.8 mmol) of chloroiridic acid aqueous solution, weigh 0.22 g of titanium dioxide powder, and 0.52 g of citric acid (complexing agent, 2.7 mmol), stir and mix at room temperature, adjust the pH of the solution to between 4 and 5, and react at 70°C for 1 hour; wherein the molar ratio of the complexing agent to the iridium source is 1.5:1;

[0091] (2) After cooling, spin-dry at 70°C and dry in an oven at 120°C for 8 h;

[0092] (3) After the solid is taken out and cooled, it is ground and placed flat on a porcelain boat. In an air atmosphere, the temperature is increased to 400°C at a heating rate of 2°C / min and maintained for 2 h.

[0093] (4) Cool to room temperature, add a certain amount of deionized water, ultrasonically wash, centrifuge (10000 rpm, 10 min), then wash with a 1:1 mixed solvent of ethanol and water, centrifuge three times (pH test paper detection is neutral), place the centrifuge tube with the catalyst in a forced air drying oven (60 ° C) and dry for 12 h to finally obtain the catalyst, which is recorded as CAT-5.

[0094] Example 6

[0095] (1) Take 10 mL (0.35 g, 1.8 mmol) of chloroiridic acid aqueous solution, weigh 0.22 g of titanium dioxide powder, and 0.36 g of malic acid (complexing agent, 2.7 mmol), stir and mix at room temperature, adjust the pH of the solution to between 4 and 5, and react at 70°C for 1 hour; wherein the molar ratio of the complexing agent to the iridium source is 1.5:1;

[0096] (2) After cooling, spin-dry at 70°C and dry in an oven at 120°C for 8 h;

[0097] (3) After the solid is removed and cooled, it is ground and placed flat on a porcelain boat. In an air atmosphere, the temperature is increased to 420°C at a heating rate of 2°C / min and maintained for 2 h.

[0098] (4) Cool to room temperature, add a certain amount of deionized water, ultrasonically wash, centrifuge (10000 rpm, 10 min), then wash with a 1:1 mixed solvent of ethanol and water, centrifuge three times (pH test paper detection is neutral), place the centrifuge tube with the catalyst in a forced air drying oven (60 ° C) and dry for 12 h to finally obtain the catalyst, which is recorded as CAT-6.

[0099] Comparative Example 1

[0100] Commercial iridium dioxide catalyst was purchased from Sigma Aldrich with product number 206237 and was recorded as D1.

[0101] Comparative Example 2

[0102] The catalyst was prepared by the same method as in Example 1, except that:

[0103] In step (1), no citric acid complexing agent was added, and the other processes were the same as in Example 1; the obtained catalyst product was recorded as D2.

[0104] The electrochemical performance test data of the catalysts obtained in the above examples and comparative examples (initial overpotential, mV, recorded as G1; final overpotential, mV, recorded as G2; test current density 10 mA / cm 2 , initial mass specific activity of the catalyst at 1.45 V vs. RHE, A / g (Ir) , denoted as M); at the same time, the weight content of Ir in the tested catalyst, the particle size of iridium oxide, and the specific surface area of ​​the catalyst are listed in Table 1 below.

[0105] Table 1

[0106]

[0107] According to the data in Table 1:

[0108] Compared with catalysts D1 to D2 in comparative examples 1 to 2, catalysts CAT-1 to CAT-6 prepared by the method provided in the present disclosure have lower overpotential G1 and higher mass specific activity, indicating that CAT-1 to CAT-6 have higher oxygen evolution activity.

[0109] Furthermore, compared to iridium dioxide catalyst D1, the catalysts provided by the present disclosure can effectively reduce the amount of precious metal iridium used. Compared to D2 (prepared without the addition of a complexing agent), the iridium component in CAT-1 to CAT-6 is more evenly dispersed on the support surface and has smaller particles, demonstrating that the addition of a complexing agent during the preparation process of the present disclosure can effectively improve the dispersion of the raw materials and reduce the particle size of the active component.

[0110] Furthermore, by comparing Example 1 with Example 4, it can be seen that within the preferred molar ratio range of the complexing agent to the iridium source in terms of iridium of the present disclosure, the resulting catalyst has a lower overpotential G1, a higher mass specific activity, and a higher oxygen evolution activity. By comparing Example 1 with Example 5, it can be seen that within the preferred calcination range of the present disclosure, the resulting catalyst has a lower overpotential G1, a higher mass specific activity, and a higher oxygen evolution activity.

[0111] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the scope of protection of the present disclosure.

[0112] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0113] In addition, the various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. An iridium-containing supported catalyst, characterized in that The catalyst comprises a carrier and an active component supported on the carrier, wherein the carrier is one of titanium dioxide, niobium pentoxide and tantalum pentoxide, and the active component is iridium oxide; The XRD spectrum of the catalyst contains characteristic peaks of the carrier and an amorphous peak package of iridium oxide.

2. The catalyst according to claim 1, wherein The XRD spectrum of the catalyst does not have the crystal plane diffraction peak of the iridium oxide, and the amorphous peak package only exists between 30° and 40°.

3. The catalyst according to claim 1, wherein The XRD spectrum of the catalyst shows crystal plane diffraction peaks of the carrier at 22-33 degrees and 39-49 degrees respectively.

4. The catalyst according to claim 1, wherein The Ir 4f characteristic peak of the XPS spectrum of the catalyst contains an Ir(IV) characteristic peak, and does not have characteristic peaks of elemental Ir and Ir(III).

5. The catalyst according to claim 1, wherein Based on the weight of the catalyst, the weight content of Ir is 40-60 wt%. The catalyst according to claim 1 , wherein The particle size of the active component in the catalyst is 2 to 6 nm, and the specific surface area of ​​the catalyst is 80 to 120 m 2 / g.

7. A method for preparing an iridium-containing supported catalyst, characterized in that: The method comprises the following steps: S1, mixing an iridium source, a carrier, a complexing agent and water, adjusting the pH of the mixture to 3-6, and reacting to obtain a reaction mass, wherein the complexing agent is selected from one or more of C4-C8 organic polyacids and soluble salts thereof; S2, separating water from the reaction material to obtain a supported catalyst precursor; S3, calcining the supported catalyst precursor in an oxygen-containing atmosphere; The carrier is selected from one of crystalline titanium dioxide, niobium pentoxide and tantalum pentoxide.

8. The method according to claim 7, wherein: The iridium source is selected from one or more of chloroiridic acid and chloroiridic acid alkali metal salts; preferably, the chloroiridic acid alkali metal salt is selected from one or both of potassium chloroiridate and sodium chloroiridate; The particle size of the carrier is less than 100 nm; The complexing agent is selected from one or more of citric acid, tartaric acid, malic acid, succinic acid, sodium citrate, sodium tartrate, sodium malate and sodium succinate.

9. The method according to claim 7, wherein: In step S1, the molar ratio of the complexing agent to the iridium source is 1 to 2:1, preferably 1.4 to 1.7:

1.

10. The method according to claim 7, wherein: In step S1, the reaction conditions include: temperature of 50-80°C, preferably 60-70°C; reaction time of 0.5-4h, preferably 1-2h; Preferably, in step S1, the pH of the mixed material is 4 to 5; Optionally, a pH regulator is added to adjust the pH. Optionally, the pH regulator is selected from one or more of sodium carbonate, sodium bicarbonate, sodium hydroxide and ammonia water.

11. The method according to claim 7, wherein: In step S3, the calcination conditions include: a calcination temperature of 400-500°C, preferably 420-450°C; a calcination time of 1-3 hours, preferably 2-2.5 hours; and an oxygen content of 20-80% by volume in the oxygen-containing atmosphere.

12. An iridium-containing supported catalyst prepared by the method according to any one of claims 7 to 11.

13. Use of the catalyst according to any one of claims 1 to 6 and claim 12 in producing hydrogen by electrolysis of water.

14. 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, characterized in that: The anode catalyst layer uses the catalyst described in any one of claims 1 to 6 and claim 12.

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