OER core-shell catalyst, preparation method and electrochemical device thereof

Abstract

The invention discloses an OER core-shell catalyst, a preparation method and an electrochemical device thereof. The OER catalyst comprises a crystalline / amorphous Pt (at) RuIrOx ultrafine nanowire. According to the preparation method, the PtRuIr superfine nanowire with the surface rich in oxyphilic Ru or Ir elements is firstly prepared by adopting a two-step liquid phase direct reduction method, and c / a-Pt at RuIrOx NWs with the surface containing an amorphous active shell layer is successfully prepared by combining an in-situ oxidation induced amorphization strategy and optimizing components and reaction conditions, so that excellent OER catalytic activity and stability are shown. The electrochemical device assembled by the OER catalyst not only breaks through the limitation of low stability of an amorphous oxide material in OER electro-catalysis, but also opens up a new way for practical application of a low-dimensional amorphous nano material in the electro-catalysis field, and shows remarkable advancement and innovation.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrolytic water oxygen evolution catalysts, and specifically relates to an OER core-shell catalyst, a preparation method thereof, and an electrochemical device. Background Art

[0002] As a clean and efficient energy carrier, hydrogen has broad application prospects. According to different hydrogen production methods, it can be divided into three types: gray hydrogen, blue hydrogen, and green hydrogen. Among them, green hydrogen with high purity and zero carbon emissions can be produced by electrolyzing water and applied to multiple fields such as transportation, aviation, and navigation. Currently, the relatively mature electrolytic water hydrogen production devices include two types: alkaline water electrolyzers (AWE) and proton exchange membrane water electrolyzers (PEMWE). Compared with AWE, PEMWE has attracted wide attention due to its advantages such as compact device structure, high energy density, high gas purity, low permeability, fast response speed, and fast start-stop (B. Xia, et al. Chem. Soc. Rev., 2023, 52, 5652 - 5683.). However, since the PEM electrolyzer needs to operate under strong acidic and highly oxidative working conditions, the anode needs to rely on a large amount of noble metal catalysts (such as Ir, Ru), resulting in high equipment costs and its service life is not as good as that of alkaline electrolysis water technology (Q. Ma and S. Mu, Interdisc. Mater., 2023, 2, 53 - 90.). Therefore, there is an urgent need for low-cost, high-activity, and high-stability anode OER catalysts to improve the overall working efficiency of PEMWE.

[0003] IrO 2 is generally considered to be the most advanced OER catalyst in PEM electrolytic water, but the low reserves and high cost of Ir severely restrict its large-scale application in PEMWE (W. Luo, et al. Nat. Commun., 2024, 15, 5419.). However, among many OER catalysts, RuO 2 exhibits the highest OER activity and low cost, but it is unstable under the operating conditions of the electrolyzer (>~100 h) (H. Wang, et al. Nat. Mater. 2023, 22, 100–108.). The Mom research group (R. Mom, et al. ACS Catal., 2023, 13, 7488 - 7498.) explored the in-situ structural evolution of ruthenium oxide during the acidic OER process through in-situ synchrotron radiation technology, and the results showed that the OER onset potential of amorphous RuO x is lower than that of its crystalline counterpart, which may be because amorphous RuO xThe activation of lattice oxygen in the crystal is higher than that in polycrystalline RuO 2 However, the activation of lattice oxygen will cause irreversible dissolution of amorphous oxides during the OER process, thus deactivating them and making it difficult to maintain good catalytic stability. x The unbalanced relationship between the activity and stability of the material seriously hinders its application in OER catalytic reactions. Therefore, it is still necessary to design amorphous Ru-based OER catalysts with both high activity and high stability.

[0004] On the other hand, ultrafine nanowire morphology has attracted much attention in the field of electrocatalysis due to its advantages such as high atomic exposure ratio, inherent isotropy, rich high-index crystal planes, good conductivity, and good structural stability (Y. Du, et al. Adv. Funct. Mater. 2020, 30, 2000793. & S. Xie, et al. Adv. Funct. Mater. 2023, 33, 2304125.). Designing OER catalysts based on ultrafine nanowire morphology can effectively improve the atomic utilization of catalysts, further reduce the cost of catalysts, and improve the cost-effectiveness of water electrolysis devices.

[0005] In summary, it is still a huge challenge to accurately construct a stable amorphous oxide active shell on ultrafine nanowires. Compared with alkaline water electrolysis to produce hydrogen, the more harsh acidic working environment and high oxidation working potential in proton exchange membrane water electrolysis have higher requirements on the stability of OER catalysts. In the field of proton exchange membrane water electrolysis to produce hydrogen, how to prepare amorphous anode oxygen evolution catalysts that are low-cost, highly active, and highly stable is a technical problem that needs to be solved urgently. Summary of the invention

[0006] The purpose of the present invention is to overcome the deficiencies of the prior art and provide an OER core-shell catalyst and a preparation method and an electrochemical device thereof, which solve the problems in the above-mentioned background technology.

[0007] One of the technical solutions adopted by the present invention to solve the technical problem is: providing an OER core-shell catalyst having crystalline and amorphous Pt@RuI rO x Ultrafine nanowires, wherein the core layer includes Pt and the shell structure includes disordered RuIrO coated on the surface x ; The molar ratio of Pt, Ru and Ir is 0.1-5:0.1-5:0.1-5, and the ratio of the molar number of Ir to the total molar number of Pt, Ru and Ir is 0.01-0.6:1.

[0008] The above Pt, Ru, and Ir metal ratios directly affect the activity and stability of the catalyst. When feeding materials, the PtRuIr metal ratio is adjusted as above. Especially when controlling the molar ratios of the three metals as above, while keeping the amount of Ir within the above lower range, it is preferably that the molar ratio of Ir to the total molar amount of Pt, Ru, and Ir is (0.5 - 0.15):1, specifically preferably 0.11:1, 0.14:1, etc., so that the c / a-Pt@RuIrO x The surface of the ultra-fine nanowires maintains an active shell layer with a certain amorphous structure and still maintains a good nanowire morphology. Therefore, the OER catalyst not only has high activity but also good stability, showing a high degree of advancement.

[0009] It should be noted that the degree of amorphization of c / a-Pt@RuO x NWs without Ir doping is lower than that of c / a-Pt@RuIrO x NWs catalyst. Under the OER working conditions, the dissolution of Ru metal is very rapid, resulting in serious performance degradation. By doping with Ir, both the disordered RuO x active layer on the surface and the morphology of the ultra-fine nanowires are stabilized, making the c / a-Pt@RuIrO x NWs catalyst not only has good activity but also better stability.

[0010] In a preferred embodiment of the present invention, the core layer further includes alloy nanowires formed by Pt, Ru, and Ir, and the shell layer structure includes a composite structure of Ru and Ir oxide crystals and disordered RuIrO x .

[0011] The second technical solution adopted by the present invention to solve its technical problems is: providing a preparation method of an OER core-shell catalyst, including the following steps:

[0012] (1) Prepare a mixed solution from a platinum precursor and a structure-directing agent, then add a carbonyl salt as a reducing agent, and react at 130 - 220 °C under an oil bath condition for 0.5 - 4 h to obtain a colloidal dispersion of platinum nanowires as a template;

[0013] (2) Prepare a mixed solution from a ruthenium precursor and an iridium precursor, add it to the colloidal dispersion, and continue to react at 150 - 250 °C under an oil bath condition for 1 - 5 h to reduce and obtain PtRuIr ternary alloy nanowires, denoted as PtRuIr NWs;

[0014] (3) Load PtRuIr NWs on a carrier, and perform in-situ oxidative heat treatment on the loaded catalyst in an air atmosphere at 100 - 500 °C for 1 - 10 h to obtain an OER catalyst, denoted as c / a-Pt@RuIrO x NWs.

[0015] In a preferred embodiment of the present invention, in step (1), the platinum precursor includes platinum acetylacetonate, the structure-directing agent is cetyltrimethylammonium chloride or cetyltrimethylammonium bromide, and the carbonyl salt includes molybdenum hexacarbonyl or tungsten hexacarbonyl.

[0016] In a preferred embodiment of the present invention, in step (1), the molar ratio of the platinum precursor, the structure-directing agent, and the carbonyl salt is 0.01 - 5:0.04 - 19:0.04 - 22.

[0017] In a preferred embodiment of the present invention, in step (2), the ruthenium precursor includes dodecacarbonyltriruthenium or ruthenium acetylacetonate, and the iridium precursor includes iridium chloride or iridium acetylacetonate.

[0018] In a preferred embodiment of the present invention, in step (2), the molar ratio of the ruthenium precursor to the iridium precursor is 0.01 - 6:0.01 - 3; the molar ratio of the iridium precursor to the total molar amount of all precursors is 0.01 - 0.6:1.

[0019] In a preferred embodiment of the present invention, in step (1) or (2), the solvent used for preparing the mixed solution is oleylamine or octadecene. The solvent dosage in step (1) is 1 - 10 mL, and the solvent dosage in step (2) is 0.5 - 5 mL.

[0020] In a preferred embodiment of the present invention, the specific temperature of the oil bath can be 160 °C, 180 °C, 200 °C, etc., and the specific reaction time can be 3 h, 3.5 h, etc. By controlling the temperature of the oil bath and the reaction time, the reduction rate of each component metal in the colloidal solution can be regulated, thereby preparing PtRuIr ternary metal precatalysts with different ratios.

[0021] In a preferred embodiment of the present invention, the heat treatment adopts one of tube furnace heating and muffle furnace heating.

[0022] In a preferred embodiment of the present invention, in step (3), the carrier is selected from one or more of carbon black, carbon nanotubes, titanium dioxide, aluminum oxide, and silicon dioxide; the carbon black is selected from XC-72 and / or Ketjenblack; the appearance of the carrier is in the form of particles or powder, and the particle size is 5 - 80 nm.

[0023] The third technical solution adopted by the present invention to solve its technical problems is: providing an electrochemical device, including a proton exchange membrane electrode for electrolytic water hydrogen production, and the catalyst coating on the electrode surface adopts the above-mentioned OER core-shell catalyst.

[0024] In a preferred embodiment of the present invention, based on the above OER catalyst, a proton exchange membrane electrode can be prepared by the catalysts coated membrane (CCM) method or the catalysts coated substrate (CCS) method. The coating method of the catalyst coating can be selected from electrostatic spraying method, direct knife coating method, thermal transfer printing method, etc. Components such as the gas diffusion layer used in the proton exchange membrane electrode and the thickness of the catalyst layer can be set conventionally.

[0025] Compared with the background art, this technical solution has the following advantages:

[0026] (1) The method for preparing the crystalline / amorphous OER core-shell catalyst of the present invention utilizes the strategy of in-situ oxidation-induced amorphization. Under the action of surface oxygenophilic elements Ru / Ir-rich, the ultrafine PtRuIr ternary alloy nanowires undergo in-situ oxidation, and the Ru–O or Ir-O bonds disrupt the originally ordered metal–metal bonds, thereby preparing the surface amorphous c / a-Pt@RuIrO x NWs catalyst.

[0027] (2) Through ratio optimization of the OER catalyst of the present invention, low iridium doping is realized, so that the active surface of the c / a-Pt@RuIrO x NWs catalyst maintains a certain amorphous structure. The characteristics of this ultra-low dimensional and surface amorphous structure endow the c / a-Pt@RuIrO x NWs catalyst with high activity and high stability.

[0028] (3) The OER catalyst of the present invention exhibits excellent catalytic activity and stability. Using it as a catalyst coating to prepare an electrochemical device assembled with a proton exchange membrane electrode deeply explores the application prospects of low-dimensional amorphous nanomaterials in the field of electrocatalysis and has a high degree of advancement. Description of the Drawings

[0029] Figure 1 Transmission electron microscope images and elemental mapping images of the crystalline / amorphous Pt@RuIrO x ultrafine nanowires prepared in Example 1, (a) transmission electron microscope image; (b, c) high-resolution transmission electron microscope images; (d, e) HAADF-STEM images and elemental mapping images; (f) line scan analysis image.

[0030] Figure 2 X-ray diffraction spectra of the OER catalyst prepared in Example 1 and PtRuIr NWs.

[0031] Figure 3 X-ray diffraction spectra of the OER catalyst prepared in Example 1 and c / a-Pt@RuO of Comparative Example 1 xX-ray diffraction pattern of NWs.

[0032] Figure 4 c / a-Pt@RuO NWs prepared in Comparative Example 1 x and the precatalyst Pt 30 Ru 70 X-ray diffraction pattern of NWs.

[0033] Figure 5 Pt@IrO NWs prepared in Comparative Example 2 x X-ray diffraction pattern of NWs.

[0034] Figure 6 OER catalyst prepared in Example 1 and c / a-Pt@RuO NWs and Pt@IrO NWs prepared in Comparative Example 1 and Comparative Example 2 x and the commercial RuO x NWs 2 Linear sweep voltammetry test line graph.

[0035] Figure 7 Stability test result graph of the OER catalyst prepared in Example 1.

[0036] Figure 8 Current-voltage curve graph of the proton exchange membrane electrode electrolyzed water device prepared with the OER catalyst of Example 1.

[0037] Figure 9 Stability test result graph of the proton exchange membrane electrode electrolyzed water device prepared with the OER catalyst of Example 1. Detailed implementation mode

[0038] The present application will be further described in detail below through the accompanying drawings and examples. Through these descriptions, the features and advantages of the present application will become clearer and more definite.

[0039] In the present invention, the term "OER" represents the oxygen evolution reaction. The term "ICP-MS" represents an inductively coupled plasma mass spectrometer. In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0040] In the following examples, unless otherwise specified, the experimental instruments and raw materials involved are all commercially available products.

[0041] Description of reagents used in the following examples, comparative examples or test examples:

[0042] The proton exchange membrane was purchased from Suzhou Shengnuoke Technology Co., Ltd., and the model number was N115.

[0043] The ionomer Nafion D520 was purchased from Sciengine, with the brand name of DuPont.

[0044] The commercial Pt / C was purchased from Xiamen Jiaqing Technology Co., Ltd., with the brand name of XMC SF-1024.

[0045] Commercial RuO 2 was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., with the brand name of R111923.

[0046] Example 1

[0047] This example provides the preparation of an OER catalyst, including the following steps:

[0048] (1) In a 25 mL reaction flask, 0.025 mmol of platinum acetylacetonate (Pt(acac) 2 ), 0.094 mmol of cetyltrimethylammonium chloride (CTAC), and 5 mL of oleylamine (OAm) were successively added. Stir at room temperature for 20 min and sonicate for 40 min, then add the reducing agent molybdenum hexacarbonyl (Mo(CO) 6 ). Place it in an oil bath at 180 °C and react for 3 h to obtain a colloidal dispersion of platinum nanowires (Pt NWs) as a template.

[0049] (2) Weigh 0.034 mmol of dodecacarbonyltriruthenium (Ru 3 (CO) 12 ) and 0.025 mmol of iridium(III) chloride trihydrate (IrCl 3 ·3H 2 O), put them into a 5 mL sample bottle, add 2 mL of oleylamine to dissolve to obtain a mixed solution. Add the newly prepared mixed solution to the colloidal dispersion of Pt NWs in step (1), raise the oil bath temperature to 200 °C, and continue to react for 3.5 h to obtain a colloidal dispersion of PtRuIr ternary alloy nanowires (PtRuIr NWs).

[0050] (3) Wash and centrifuge the colloidal dispersion of PtRuIr NWs in step (2) 3 - 4 times with a mixed solvent of n-hexane and ethanol to remove the residual oleylamine and structure-directing agent on the nanowires, thereby obtaining PtRuIr NWs. The washed PtRuIr NWs were redispersed in 3 mL of n-hexane for standby.

[0051] (4) After determining the concentration of each component metal in the PtRuIr NWs dispersion in step (3) by ICP-MS, a certain amount of PtRuIr NWs dispersion was taken according to a noble metal loading of 40 wt.%, and added to 2 mg mL -1In the activated carbon dispersion liquid, under the condition of an ice bath (<30 °C), ultrasonic treatment was carried out for 2 h to obtain carbon-supported PtRuIr NWs; the carbon-supported PtRuIr NWs were collected by centrifugation, redispersed in 5 mL of ethanol, transferred to a 25 mL reaction flask, 5 mL of acetic acid was added, and after oil bath at 70 °C for 24 h, it was washed 3 times with ethanol and placed in a vacuum drying oven at 60 °C for drying for 12 h.

[0052] (5) Place the dried carbon-supported PtRuIr NWs powder obtained in step (4) in a muffle furnace and heat-treat to obtain an OER catalyst powder, with a heating rate of 5 °C min -1 , the reaction temperature is 200 °C, the reaction atmosphere is air, and the reaction time is 4 h.

[0053] Example 2

[0054] Prepare the OER catalyst according to the method of Example 1, the difference is that:

[0055] In step (2), the amount of Ru 3 (CO) 12 is 0.021 mmol, and the amount of IrCl 3 ·3H 2 O is 0.051 mmol.

[0056] Example 3

[0057] Prepare the OER catalyst according to the method of Example 1, the difference is that:

[0058] In step (2), the amount of IrCl 3 ·3H 2 O is 0.051 mmol.

[0059] Example 4

[0060] Prepare the OER catalyst according to the method of Example 1, the difference is that:

[0061] In step (1), the amount of Pt(acac) 2 is 0.125 mmol, the amount of CTAC is changed to 0.188 mmol, the amount of oleylamine is changed to 25 mL, and the amount of Mo(CO) 6 is 0.55 mmol; in step (2), the amount of Ru 3 (CO) 12 is 0.17 mmol, the amount of IrCl 3 ·3H 2 O is 0.125 mmol, and the amount of oleylamine is changed to 10 mL; the reaction vessel is changed to a 100 mL round-bottom flask.

[0062] Example 5

[0063] Prepare the OER catalyst according to the method of Example 1, with the differences being:

[0064] In step (1), change the dosage of Pt(acac) 2 to 0.25 mmol, change the dosage of CTAC to 0.94 mmol, change the dosage of oleylamine to 50 mL, and change the dosage of Mo(CO) 6 to 1.1 mmol; in step (2), change the dosage of Ru 3 (CO) 12 to 0.34 mmol, change the dosage of IrCl 3 ·3H 2 O to 0.25 mmol, change the dosage of oleylamine to 20 mL; change the reaction vessel to a 250 mL round-bottom flask.

[0065] Example 6

[0066] Prepare the OER catalyst according to the method of Example 1, with the differences being:

[0067] In step (1), change the dosage of Pt(acac) 2 to 0.50 mmol, change the dosage of CTAC to 1.88 mmol, change the dosage of oleylamine to 100 mL, and change the dosage of Mo(CO) 6 to 2.2 mmol; in step (2), change the dosage of Ru 3 (CO) 12 to 0.68 mmol, change the dosage of IrCl 3 ·3H 2 O to 0.50 mmol, change the dosage of oleylamine to 40 mL; change the reaction vessel to a 500 mL round-bottom flask.

[0068] Example 7

[0069] Prepare the OER catalyst according to the method of Example 1, with the differences being:

[0070] In step (1), change the dosage of Pt(acac) 2 to 2.5 mmol, change the dosage of CTAC to 9.4 mmol, change the dosage of oleylamine to 500 mL, and change the dosage of Mo(CO) 6 to 11.0 mmol; in step (2), change the dosage of Ru 3 (CO) 12 to 3.4 mmol, change the dosage of IrCl 3 ·3H 2The dosage of O is 2.5 mmol, and the dosage of oleylamine is changed to 200 mL; the reaction vessel is changed to a 1000 mL round-bottom flask.

[0071] Comparative Example 1

[0072] The OER catalyst was prepared according to the method of Example 1, except that:

[0073] IrCl 3 ·3H 2 O was not used, and the dosage of Ru 3 (CO) 12 was changed to 0.031 mmol in step (2) to prepare c / a-Pt@RuO x NWs.

[0074] Comparative Example 2

[0075] The OER catalyst was prepared according to the method of Example 1, except that:

[0076] Ru 3 (CO) 12 was not used, the dosage of Pt(acac) 2 was changed to 0.050 mmol in step (1), and the dosage of CTAC was changed to 0.188 mmol; the dosage of IrCl 3 ·3H 2 O was changed to 0.017 mmol in step (2), and 0.038 mmol of Mo(CO) 6 was added simultaneously to prepare Pt@IrO x NWs.

[0077] The samples prepared in the examples and comparative examples were tested as follows:

[0078] I. The OER catalyst prepared in Example 1 above was characterized for its morphology and composition using transmission electron microscopy and elemental mapping line scanning analysis. The obtained transmission electron microscopy images and line scanning analysis results are as Figure 1 shown.

[0079] It can be seen through Figure 1 that the OER catalyst prepared in Example 1 consists of a disordered shell and a crystalline core. The lattice fringe spacing of 0.228 nm was measured in the crystalline region, which belongs to the Pt(111) plane; combined with the line scanning analysis, it can be concluded that the disordered shell is mainly RuIrO x , so this result preliminarily indicates that c / a-Pt@RuIrO with a disordered surface has been successfully prepared x NWs.

[0080] II. The OER catalyst prepared in Example 1 above and the PtRuIr NWs prepared in Example 1 were characterized using an X-ray diffractometer, and the obtained X-ray diffraction (XRD) spectra are as Figure 2 shown.

[0081] By Figure 2 comparison, it can be seen that new XRD diffraction peaks appeared in the OER catalyst prepared in Example 1, corresponding to the diffraction peaks of rutile RuO 2 (JCPDS No. 88-0322), and the XRD diffraction peaks corresponding to the face-centered cubic phase (Pt JCPDS No. 04-0802) showed obvious broadening and weakening of the signal intensity, indicating that the nanowires with surface oxygenophilic elements Ru / Ir underwent in-situ oxidation, and the disordered Ru–O / Ir–O bonds broke the ordered metal–metal bonds, resulting in the preparation of surface-disordered c / a-Pt@RuIrO x NWs.

[0082] The OER catalyst prepared in Example 1 above and the c / a-Pt@RuO x NWs prepared in Comparative Example 1 were characterized using an X-ray diffractometer, and the obtained X-ray diffraction (XRD) spectra are as Figure 3 shown.

[0083] By Figure 3 comparison, it can be seen that the intensity of the XRD diffraction peaks attributed to rutile RuO 2 (JCPDS No. 88-0322) in the OER catalyst prepared in Example 1 was significantly weaker than that of the c / a-Pt@RuO x NWs catalyst, indicating that the OER catalyst prepared in Example 1 had a higher degree of disorder, and this result shows that the doping of Ir has a positive effect on stabilizing the disordered structure on the surface.

[0084] The OER catalyst c / a-Pt@RuO x NWs prepared in Comparative Example 1 and the pre-catalyst Pt 30 Ru 70 NWs were characterized using an X-ray diffractometer, and the obtained X-ray diffraction (XRD) spectra are as Figure 4 shown.

[0085] The OER catalyst Pt@IrO x NWs prepared in Comparative Example 2 was characterized using an X-ray diffractometer, and the obtained X-ray diffraction (XRD) spectra are as Figure 5 shown.

[0086] III. The catalysts prepared in Example 1, Comparative Example 1, and Comparative Example 2 were analyzed by ICP-MS.

[0087] The ICP-MS test method is as follows: Take different catalyst dispersions and digest them in 2 mL of aqua regia (the preparation scheme of aqua regia is that the volume ratio of hydrochloric acid to nitric acid is 3:1). Take a certain amount of the digestion solution and dilute it with a 2% (volume fraction) dilute nitric acid solution until the metal concentration is controlled within 100 ppb. The metal concentration of the calibration solution used for the ICP-MS concentration calibration curve is also controlled within 100 ppb. The obtained test results are shown in Table 1 below.

[0088] Table 1

[0089]

[0090] IV. For the OER catalyst prepared in Example 1 above and the c / a-Pt@RuO x NWs and Pt@IrO x NWs prepared in Comparative Example 1 and Comparative Example 2, as well as commercial RuO 2 perform linear sweep voltammetry tests.

[0091] It can be seen from Figure 6 that the performance of the nanocatalyst prepared in Example 1 is superior to that of the c / a-Pt@RuO x NWs and Pt@IrO x NWs catalysts prepared in the comparative examples, and the catalyst prepared in Example 1 has an anodic overpotential of only 146 mV and 282 mV at 10 mA cm -2 and 600 mA cm -2 respectively, and can reach a high current density of 1000 mA cm -2 . This means that the performance of this catalyst is at a leading level and has the potential to be applied to high-current devices.

[0092] V. Perform stability tests on the c / a-Pt@RuIrO x NWs catalyst prepared in Example 1 above, the c / a-Pt@RuO x NWs catalyst in Comparative Example 1, and commercial RuO 2 .

[0093] The internal resistance of the proton exchange membrane water electrolysis device is higher, resulting in a higher working voltage, and higher stability requirements for the anodic OER catalyst. Perform stability tests on the c / a-Pt@RuIrO x NWs catalyst prepared in Example 1 above, the c / a-Pt@RuO x NWs catalyst in Comparative Example 1, and commercial RuO 2 . The specific test method is as follows: Drop the catalyst slurry (the noble metal content is 200 μg) on a 1 cm 2The gas diffusion layer is used as the working electrode, the counter electrode is a platinum mesh, the reference electrode is a saturated calomel electrode, and the electrolyte is 0.5M H 2 SO 4 solution. The chronopotentiometry is used to conduct the stability test at a current density of 10 mA cm -2 . The results are as Figure 7 shown. It can be seen from Figure 7 that the catalytic stability of the c / a-Pt@RuIrO x NWs catalyst prepared in Example 1 is better than other comparative samples.

[0094] VI. The OER catalyst prepared in the above Example 1 is tested in a proton exchange membrane electrolyzer device.

[0095] The current-voltage curve is measured by the stepwise constant current charging method, as Figure 8 shown. The preparation process of the proton exchange membrane electrolyzer device is as follows: (1) The catalyst powder prepared in Example 1 is made into an anode electrode by the CCM method (the electrode area is 4 cm 2 ), and the specific slurry conditions are: the catalyst concentration is 1.5 mg mL -1 (the noble metal concentration contained therein is 0.6 mg PGM mL -1 ), the volume ratio of isopropanol to ultrapure water is 7:3, and the content of Nafion is 25%. The commercial Pt / C powder is made into a cathode electrode by the CCM method, and the specific slurry conditions are: the catalyst concentration is 0.5 mg mL -1 (the noble metal concentration contained therein is 0.2 mg Pt mL -1 ), and the ratio of the solvents used and the amount of Nafion are the same as above; (2) The prepared proton exchange membrane electrode is tested by a standard method, the test temperature is 80 °C, and the test solution is ultrapure water with a conductivity of 0.9 - 1.0 μS cm.

[0096] It can be seen from Figure 8 that the working voltages of the device at current densities of 1 A cm -2 , 2 A cm -2 and 5 A cm -2 are 1.55 V, 1.70 V and 2.02 V respectively, showing good electrolytic water performance.

[0097] VII. The stability test of the proton exchange membrane electrolyzer device is carried out on the above-prepared proton exchange membrane electrode.

[0098] The results are as Figure 9 shown. During the 1500 h proton exchange membrane electrolysis stability test of the device, the voltage decay rate is only 0.16 mV h -1, with good electrolyzed water stability.

[0099] In summary, the present invention provides a preparation method of an anode catalyst with elements such as high activity, high stability, and high cost-effectiveness, which can significantly reduce energy consumption and electrode cost, thereby effectively reducing the hydrogen production cost.

[0100] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An OER core-shell catalyst, characterized in that: Including crystalline and amorphous Pt@RuIrO x Ultrafine nanowires; wherein the core layer includes Pt, and the shell structure includes disordered RuIrO coated on the surface x ; The molar ratio of Pt, Ru and Ir is 0.1-5:0.1-5:0.1-5, and the ratio of the molar number of Ir to the total molar number of Pt, Ru and Ir is 0.01-0.6:

1.

2. An OER core-shell catalyst according to claim 1, characterized in that: The core layer also includes alloy nanowires formed by Pt, Ru and Ir, and the shell layer structure includes Ru and Ir oxide crystals and disordered RuIrO x composite structure.

3. A method for preparing an OER core-shell catalyst, characterized in that: The steps include: (1) preparing a mixed solution of a platinum precursor and a structure directing agent, then adding a carbonyl salt as a reducing agent, reacting for 0.5 to 4 hours in an oil bath at 130 to 220° C., and obtaining a colloidal dispersion of platinum nanowires as a template; (2) preparing a mixed solution of a ruthenium precursor and an iridium precursor, adding the mixed solution to the colloidal dispersion, and continuing to react in an oil bath at 150 to 250° C. for 1 to 5 hours to obtain PtRuIr ternary alloy nanowires, which are referred to as PtRuIr NWs; (3) PtRuIr NWs were loaded on a carrier, and the loaded catalyst was subjected to in-situ oxidation heat treatment at 100-500 °C in an air atmosphere for 1-10 h to obtain an OER catalyst, which was denoted as c / a-Pt@RuIrO x NWs.

4. The method for preparing an OER core-shell catalyst according to claim 3, characterized in that: In step (1), the platinum precursor includes platinum acetylacetonate, the structure directing agent is hexadecyltrimethylammonium chloride or hexadecyltrimethylammonium bromide, and the carbonyl salt includes hexacarbonyl molybdenum or hexacarbonyl tungsten.

5. The method for preparing an OER core-shell catalyst according to claim 3, characterized in that: In step (1), the molar ratio of the platinum precursor, the structure directing agent, and the carbonyl salt is 0.01-5:0.04-19:0.04-22.

6. The method for preparing an OER core-shell catalyst according to claim 3, characterized in that: In step (2), the ruthenium precursor includes triruthenium dodecacarbonyl or ruthenium acetylacetonate, and the iridium precursor includes iridium chloride or iridium acetylacetonate.

7. The method for preparing an OER core-shell catalyst according to claim 3, characterized in that: In step (2), the molar ratio of the ruthenium precursor to the iridium precursor is 0.01-6:0.01-3; the total molar ratio of the iridium precursor to all precursors is 0.01-0.6:

1.

8. The method for preparing an OER core-shell catalyst according to claim 3, characterized in that: The solvent used in preparing the mixed solution in step (1) or (2) is oleylamine or octadecene, the amount of the solvent used in step (1) is 1 to 10 mL, and the amount of the solvent used in step (2) is 0.5 to 5 mL.

9. The method for preparing an OER core-shell catalyst according to claim 3, characterized in that: In step (3), the carrier is selected from one or more of carbon black, carbon nanotubes, titanium dioxide, aluminum oxide and silicon dioxide; the carbon black is selected from XC-72 and / or Ketjen black; the carrier has the appearance of particles or powder, and the particle size is 5-80nm.

10. An electrochemical device, characterized in that: It comprises a proton exchange membrane electrode for producing hydrogen by electrolyzing water, wherein the catalyst coating on the surface of the electrode adopts an OER core-shell catalyst as claimed in claim 1 or 2.

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