Multifunctional synergic composite ultra-low noble metal-rare earth catalyst and preparation method thereof

Abstract

This invention discloses a multifunctional synergistic composite ultra-low loading noble metal-rare earth catalyst and its preparation method. It employs a three-in-one synergistic architecture of "noble metal active center - rare earth regulation center - support defect center," and precisely controls the noble metal loading within an ultra-low range of 0.1-1.8 wt% through a three-step process: support defect engineering, directional rare earth introduction, and noble metal loading. This method is simple, has mild reaction conditions, and is low-cost, applicable to transition metals such as nickel, cobalt, manganese, iron, and copper, as well as rare earth metal supports. The prepared catalyst exhibits excellent and stable electrocatalytic activity for hydrogen evolution and oxygen evolution even with low noble metal loading, and can operate stably for over 500 hours at industrial-grade high current densities, adapting to various electrolyte systems. This invention provides a universal, efficient, and low-cost strategy for preparing high-performance water electrolysis electrode materials, which is of significant value in promoting the large-scale application of water electrolysis for hydrogen production technology.

Description

Technical Field

[0001] This invention belongs to the field of self-supporting catalyst technology, specifically relating to a multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst and its preparation method. Background Technology

[0002] Electrolysis of water to produce hydrogen is a core technology for green hydrogen energy acquisition, in which efficient and stable electrocatalysts play a crucial role. Existing platinum-based, ruthenium-based, and other precious metal catalysts are difficult to apply on a large scale due to their high cost and scarce resources. Ultra-low loading strategies (below 2 wt%) have become the key to cost reduction, but they face three major challenges in practice: First, active species are prone to migration and aggregation under low loading, leading to a decrease in active site density and intrinsic activity; second, the interaction between traditional supports and metal species is weak, making it difficult to stably anchor active centers under harsh electrochemical conditions, resulting in easy catalyst deactivation; and third, existing preparation methods are complex, demanding, and lack universality, making it difficult to adapt to the needs of diverse electrochemical systems.

[0003] The introduction of rare earth elements provides a new approach to optimizing catalyst performance, which can regulate local electronic structure, enhance metal-support interaction and improve corrosion resistance. However, existing technologies still have significant shortcomings: the composite method is singular and lacks targeted construction of the synergistic effect of precious metals, rare earth elements and supports; the control methods are crude and it is difficult to provide real-time feedback on the dispersion state of active components, which can easily lead to uneven loading; the component combination lacks specificity and is difficult to adapt to the needs of different electrolysis environments.

[0004] Therefore, there is an urgent need to develop a simple, mild, and universally applicable preparation method to achieve ultra-low loading of noble metals and / or rare earth elements, and to allow active components to exist in multiple forms to meet the diverse requirements of different catalytic reactions for the structure of active sites. Summary of the Invention

[0005] To address the aforementioned issues, this invention proposes a multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst, along with its precise preparation method and applications. This catalyst achieves stable dispersion and efficient catalysis of active components under ultra-low loading by constructing a three-in-one synergistic system of "support defect center - rare earth regulation center - noble metal active center." Furthermore, it exhibits excellent performance in catalytic activity, structural stability, and environmental adaptability, meeting the application requirements for hydrogen production through water electrolysis in acidic, alkaline, and neutral electrolysis systems.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A multifunctional synergistic composite ultra-low loading noble metal-rare earth catalyst includes a conductive substrate, a nanostructured support layer grown on the conductive substrate, a noble metal active center and a rare earth regulatory center supported on the support layer.

[0008] The support layer is a transition metal or rare earth metal oxide / hydroxide defect support with oxygen vacancies; the noble metal active center, rare earth regulatory center and support defect center form a "main-auxiliary" synergistic catalytic system through electronic interaction;

[0009] The catalyst is prepared from the following raw materials in parts by weight:

[0010] Carrier: 2.5-37.5 parts of metal salt; when using in-situ doping process, add an additional 0.5-2.5 parts of rare earth salt for in-situ doping;

[0011] Rare Earth Regulation Center: 0.05-0.2 parts rare earth precursor, 1.5-3.0 parts complexing agent;

[0012] Precious metal active center: 1-6 parts of precious metal precursor, 0.5-2.0 parts of reducing agent;

[0013] The metal salts, rare earth precursors, and noble metal precursors mentioned herein are all water-soluble inorganic salts.

[0014] Optionally, the ligand is selected from one or more nitrogen-containing organic ligands or inorganic ammonium salts; the noble metal precursor is selected from one or more of ruthenium trichloride, chloroplatinic acid, palladium nitrate, iridium trichloride, chloroauric acid, and silver nitrate; and the reducing agent is selected from one or two of sodium borohydride and potassium borohydride.

[0015] Optionally, the preparation method of the aforementioned multifunctional synergistic composite ultra-low loading noble metal-rare earth catalyst is as follows:

[0016] S1. On a pretreated conductive substrate, oxide / hydroxide supports of transition metals or rare earth metals are prepared by electrodeposition, hydrothermal method or chemical plating, and then defect supports with oxygen vacancies are constructed by in-situ doping or calcination.

[0017] S2. The defect support of S1 is immersed in a solution containing rare earth precursors and ligands. Rare earth elements are loaded onto the support in the form of lattice doping or surface modification through coordination-hydrolysis reaction. The rare earth loading is 0.05-1 wt%.

[0018] S3. The carrier of S2 is immersed in a solution of the noble metal precursor. By monitoring the zeta potential in real time, the solution pH and the reducing agent dropping rate are dynamically adjusted to disperse the noble metal near the rare earth control center. The noble metal loading is 0.1-1.8 wt%.

[0019] S4. The product of S3 is washed, dried or calcined to obtain a multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst.

[0020] Optionally, in step S1, the conductive substrate is one or more of carbon fiber material, titanium mesh, molybdenum mesh, foam metal, and composite nickel mesh; the transition metal is one or more of nickel, cobalt, iron, copper, and manganese; and the rare earth metal is selected from one or more of lanthanum, cerium, praseodymium, neodymium, samarium, europium, and gadolinium.

[0021] Optionally, in step S1, in-situ doping involves adding 0.01-0.05 M rare earth salt during the preparation of the support; and calcination involves annealing at 200-400 °C for 2-4 hours under an inert atmosphere.

[0022] Optionally, the process parameters for electrodeposition, hydrothermal plating, and electroless plating in step S1 are as follows:

[0023] Electrodeposition method: Using a conductive substrate as the working electrode, deposition is carried out at a constant voltage of -0.8 V to -1.4 V (vs. SCE) for 5-60 minutes;

[0024] Hydrothermal method: reaction temperature 100-150℃, reaction time 2-24 hours;

[0025] Chemical plating: temperature 50-100℃, time 0.5-6 hours.

[0026] Optionally, the concentration of the precursor solution in steps S2 and S3 is 0.01 M-0.2 M, the target value of the Zeta potential in step S3 is -20 to -40 mV, the pH of the reaction solution is adjusted to 2-8, and the dropping rate of the reducing agent is 0.1-0.5 mL / min.

[0027] Optionally, the vacuum drying conditions in step S4 are 50-70℃ for 10-14 hours, and the calcination conditions are 300-900℃ for 1-3 hours.

[0028] Optionally, the catalyst is used as an electrocatalyst for hydrogen evolution reaction and / or oxygen evolution reaction, and is adapted to acidic, alkaline or neutral electrolyte systems.

[0029] The beneficial effects of this invention are as follows: Through the synergistic design of "precious metal-rare earth-support", the strong interaction among the three can effectively inhibit the aggregation and dissolution of active components, enabling the catalyst to operate stably for more than 500 hours under industrial-grade high current density with an activity decay of ≤10%. Moreover, the preparation process is mainly liquid-phase treatment, with mild conditions and simple steps, suitable for combinations of various transition metal / rare earth supports and precious metal and rare earth active components, and easy to scale up production. At the same time, the prepared catalyst, even with an extremely low precious metal loading of 0.1-1.8 wt%, still exhibits electrocatalytic activity and high stability comparable to high-loading precious metal catalysts of 5 wt% or more for hydrogen evolution and oxygen evolution, showing outstanding potential for industrial application. In addition, by flexibly adjusting the component pairing of precious metal-rare earth-support, this catalyst can be adapted to different water electrolysis systems such as acidic, alkaline, and neutral, solving the problem of the narrow applicability of traditional catalysts and providing a unified high-performance catalyst solution for hydrogen production through water electrolysis in multiple scenarios. Attached Figure Description

[0030] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0031] Figure 1 This is a schematic diagram of the catalyst prepared in Example 1 of the present invention;

[0032] Figure 2 This is a graph of the HER polarization curve obtained in Example 1 of this invention;

[0033] Figure 3 These are SEM images of the precatalyst prepared in Example 2 of this invention before and after impregnation in a noble metal solution;

[0034] Figure 4 These are SEM images of the precatalyst prepared in Example 3 of this invention before and after impregnation in a noble metal solution;

[0035] Figure 5 These are SEM images of the precatalyst prepared in Example 4 of this invention before and after impregnation in a noble metal solution;

[0036] Figure 6 These are SEM images of the precatalyst prepared in Example 5 of this invention before and after impregnation in a noble metal solution;

[0037] Figure 7 These are SEM images of the precatalyst prepared in Example 6 of this invention before and after impregnation in a noble metal solution;

[0038] Figure 8 These are STEM-HAADF images of the precatalyst prepared in Example 7 of this invention before and after impregnation in a noble metal solution;

[0039] Figure 9 These are STEM-HAADF images of the precatalyst prepared in Example 8 of this invention before and after impregnation in a noble metal solution;

[0040] Figure 10 This is the OER polarization curve of the precatalyst prepared in Example 9 of this invention;

[0041] Figure 11 This is a stability test chart of the catalyst prepared in Example 10 of the present invention;

[0042] Figure 12 This is the XRD pattern obtained from Comparative Example 1 of this invention;

[0043] Figure 13 This is a stability test diagram of the catalyst prepared in Comparative Example 2 of this invention. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0045] Example 1: This Example 1 describes a multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst, prepared from the following raw materials in parts by weight:

[0046] Support: 2.5 parts metal salt (Ni(NO3)2); 1.0 part rare earth salt (Ce(NO3)3);

[0047] Rare Earth Regulation Center: 0.05 parts rare earth precursor (Ce(acac)3), 1.5 parts coordination agent (ethylenediamine);

[0048] Noble metal active center: 1.0 part of noble metal precursor (RuCl3·3H2O);

[0049] Conductive substrate: 1 piece of carbon cloth (0.5 × 0.6 cm);

[0050] The preparation steps of the multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst in this embodiment are as follows:

[0051] S1. A carbon cloth with a size of 0.5 cm × 0.6 cm was cut as the working electrode, a platinum wire as the counter electrode, and a saturated calomel electrode as the reference electrode. The three electrode system was placed together in a mixed solution of 0.05 M Ni(NO3)2 and 0.02 M Ce(NO3)3 and electrodeposited at -1 V for 8 minutes. The resulting sample was washed with deionized water and then calcined in air at 300 °C for 2 hours to obtain a Ce-doped Ni(OH)2 defect support.

[0052] S2. Immerse the Ce-doped Ni(OH)2 defect support in a mixed solution of 0.01 M Ce(acac)3 and 0.05 M ethylenediamine (pH=4), let it stand for 2 hours, take it out, wash it with deionized water and let it air dry.

[0053] S3. Place the support treated in S2 in a 0.05 M RuCl3·3H2O solution, monitor the Zeta potential in real time, dynamically adjust the pH to 6.0, let it stand for 1 hour, take it out, wash it with deionized water and air dry it to obtain the target catalyst.

[0054] The polarization curves of the prepared catalyst are as follows: Figure 2 As shown. By Figure 2 As can be seen, this catalyst exhibits extremely excellent HER catalytic activity: at -10 mA·cm⁻¹ -2 At current density, the overpotential is only 28 mV; at -2600 mA·cm⁻¹, the overpotential is only 28 mV. -2 At the specified current density, the overpotential is only 366 mV. ICP testing indicates that the catalyst contains 0.22 wt% Ru and 0.18 wt% Ce.

[0055] Example 2: This Example 2 presents a multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst, prepared from the following raw materials in parts by weight:

[0056] Carrier: 3.75 parts of metal salt (Co(NO3)2);

[0057] Rare Earth Regulation Center: 0.15 parts rare earth precursor (La(NO3)3), 2.0 parts complexing agent (citric acid);

[0058] Noble metal active center: 1.0 part of noble metal precursor (RuCl3·3H2O);

[0059] Conductive substrate: 1 piece of carbon cloth (0.5 × 0.6 cm);

[0060] The preparation steps of the multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst in this embodiment are as follows:

[0061] S1. A carbon cloth with a size of 0.5 cm × 0.6 cm was cut as the working electrode, a platinum wire as the counter electrode, and a saturated calomel electrode as the reference electrode. The three electrode system was placed together in a 0.075 M Co(NO3)2 solution and electrodeposited at a voltage of -1 V for 8 minutes. The resulting sample was washed with deionized water and then air-dried to obtain a Co(OH)2 defect carrier.

[0062] S2. Immerse the Co(OH)2 defect carrier in a mixed solution of 0.03 M La(NO3)3 and 0.04 M citric acid (pH=3.5), let it stand for 2.5 hours, then take it out, wash it with deionized water and let it air dry.

[0063] S3. Place the support treated in S2 in a 0.05 M RuCl3·3H2O solution, monitor the Zeta potential in real time, dynamically adjust the pH to 6.0, let it stand for 1 hour, take it out, wash it with deionized water and air dry it to obtain the target catalyst.

[0064] SEM images of the catalyst before and after impregnation, as shown below Figure 3 As shown. By Figure 3 As can be seen, the original Co-based precursor is an ultrathin nanosheet structure. Upon introduction of Ru, the nanosheets undergo "collapse" and structural reorganization, transforming into nanosheets or layered structures with increased thickness and a smoother surface. This structural evolution is accompanied by strong electronic interactions between Co and Ru atoms, optimizing the electronic structure of the catalyst and significantly enhancing the catalytic activities of HER and OER. ICP testing shows that the catalyst contains 1.48 wt% Ru and 0.10 wt% La.

[0065] Example 3: This Example 3 describes a multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst, prepared from the following raw materials in parts by weight:

[0066] Support: 37.5 parts of metal salt (CuSO4);

[0067] Rare Earth Regulation Center: 0.1 parts rare earth precursor (Pr(NO3)3), 1.8 parts coordination agent (ethylenediamine);

[0068] Noble metal active center: 1.0 part of noble metal precursor (H2PtCl6·3H2O), 0.5 part of reducing agent (sodium borohydride);

[0069] Conductive substrate: One sheet of nickel foam (0.6 × 0.6 cm);

[0070] The preparation steps of the multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst in this embodiment are as follows:

[0071] S1. Cut nickel foam with dimensions of 0.6 cm × 0.6 cm and place it in a mixed solution containing 0.75 M CuSO4 and 1 M urea (CO(NH2)2) (urea is a conventional reagent used to control the morphology and defects of the carrier). The mixture is then hydrothermally reacted at 120 °C for 2 hours. The resulting sample is washed with deionized water and then vacuum dried to obtain a Cu(OH)2 active carrier with defects.

[0072] S2. Immerse the Cu(OH)2 defect carrier in a mixed solution of 0.02M Pr(NO3)3 and 0.03M ethylenediamine, let it stand for 3.0 hours, take it out, wash it with deionized water and let it air dry.

[0073] S3. Place the support treated in S2 in a 0.05 M H2PtCl6·3H2O solution, monitor the Zeta potential (target -35 mV) in real time, add sodium borohydride dropwise at a rate of 0.2 mL / min, let it stand for 1 hour, take it out, wash it with deionized water and let it dry naturally to obtain the target catalyst.

[0074] SEM images of the catalyst before and after impregnation, as shown below Figure 4 As shown. By Figure 4 It is evident that the introduction of Pt results in a dense, porous structure resembling a "jujube," significantly increasing the specific surface area. Electrochemical tests demonstrate that this catalyst exhibits excellent HER and OER catalytic activity: HER overpotential η 10 =33 mV, OER overpotential η 10 =238 mV. ICP testing showed that the catalyst contained 0.48 wt% Pt and 0.06 wt% Pr.

[0075] Example 4: This Example 4 describes a multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst, prepared from the following raw materials in parts by weight:

[0076] Carrier: 5.0 parts of metal salt (Mn(NO3)2);

[0077] Rare Earth Regulation Center: 0.2 parts rare earth precursor (Nd(NO3)3), 2.5 parts coordination agent (citric acid);

[0078] Noble metal active center: 3.0 parts of noble metal precursor (IrCl3·H2O);

[0079] Conductive substrate: one sheet of foamed iron (0.6 × 0.6 cm);

[0080] The preparation steps of the multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst in this embodiment are as follows:

[0081] S1. A piece of foamed iron with a size of 0.6 cm × 0.6 cm was cut as the working electrode, a platinum mesh as the counter electrode, and a saturated calomel electrode as the reference electrode. The three electrode systems were placed together in a 0.075 M Mn(NO3)2 solution and electrodeposited at -1.4 V for 15 minutes. The resulting sample was washed with deionized water and then air-dried to obtain a catalytically active Mn(OH)2 support.

[0082] S2. The Mn(OH)2 support was immersed in a mixed solution of 0.04 M Nd(NO3)3 and 0.05 M citric acid for 2 hours. After immersion, it was washed with deionized water and dried. The Nd loading in the support was found to be 0.12 wt%.

[0083] S3. Place the support treated in S2 in a 0.1 M IrCl3·H2O solution, monitor the Zeta potential in real time, dynamically adjust the pH to 3.8, and continue to stand and soak for 1.5 hours. After removal, wash with deionized water and dry to obtain the target catalyst.

[0084] SEM images of the catalyst before and after impregnation, as shown below Figure 5 As shown. By Figure 5 It is evident that the morphology of Mn(OH)₂ transforms from a thin-layer hexagonal prism to porous nanospheres after the introduction of Ir, resulting in a significant increase in the number of active sites. Electrochemical tests demonstrate that this catalyst exhibits excellent HER and OER catalytic activity: HER overpotential η 10 =67 mV, OER overpotential η 10 =199 mV. ICP testing showed that the catalyst contained 1.28 wt% Ir and 0.12 wt% Nd.

[0085] Example 5: This Example 5 presents a multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst, prepared from the following raw materials in parts by weight:

[0086] Support: 4.0 parts of metal salt (La(NO3)3·6H2O);

[0087] Noble metal active center: 4.0 parts of noble metal precursor (HAuCl4·4H2O);

[0088] Conductive substrate: 1 sheet of Ti mesh (0.6 × 0.6 cm);

[0089] The preparation steps of the multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst in this embodiment are as follows:

[0090] S1. Prepare a 0.05 M La(NO3)3·6H2O solution (dissolved in 40 mL of deionized water), and stir until completely transparent to obtain solution A; prepare a 0.5 M urea solution (dissolved in 40 mL of deionized water), and stir until completely dissolved to obtain solution B; slowly add solution B dropwise to solution A, and stir continuously for 30 minutes to ensure thorough mixing. Then transfer the entire mixture to a polytetrafluoroethylene liner, and simultaneously place a Ti mesh with a cut size of 0.6 cm × 0.6 cm inside. React at 150℃ for 12 hours; after washing with deionized water and drying, the resulting sample yields a La(OH)3 defect carrier;

[0091] S2. Place the La(OH)3 defect support in a 0.1 M HAuCl4·4H2O solution, let it stand for 1 h, take it out, wash it with deionized water and let it dry naturally to obtain the target catalyst.

[0092] SEM images of the catalyst before and after impregnation, as shown below Figure 6 As shown. By Figure 6 As can be seen, the morphology of the catalyst changed from a "nanoflower" structure to a "nanochain" structure after the introduction of Au, with the average diameter of the resulting nanochains being approximately 200 nm. This structural evolution not only greatly increased the specific surface area and the number of active sites of the material, but also provided an efficient channel for electron transport and reactant diffusion. ICP testing showed that the Au content in the catalyst was 0.98 wt%, and the La content was 0.52 wt%.

[0093] Example 6: This Example 6 describes a multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst, prepared from the following raw materials in parts by weight:

[0094] Support: 25.0 parts of metal salt (FeSO4·7H2O);

[0095] Rare Earth Regulation Center: 0.15 parts rare earth precursor (Sm(NO3)3), 1.6 parts coordination agent (ethylenediamine);

[0096] Noble metal active center: 5.0 parts of noble metal precursor (Pd(NO3)2) and 1.0 part of reducing agent (KBH4);

[0097] Conductive substrate: 1 piece of carbon felt (0.6 × 0.6 cm);

[0098] The preparation steps of the multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst in this embodiment are as follows:

[0099] S1. Dissolve FeSO4·7H2O in a pre-deoxygenated 1:1 water-ethanol mixture to prepare a 0.5 M solution A; dissolve KBH4 in the same deoxygenated mixture to prepare a 1.5 M solution B; under continuous argon protection and vigorous stirring at 50°C, slowly inject solution A into solution B using a syringe; after the reaction is complete, immerse carbon felt in the mixture, stir and age for 1 hour, repeating three times; wash the resulting sample with deionized water and air dry to obtain FeO. x Defect carrier;

[0100] S2, FeO x The defective carrier was immersed in a mixed solution of 0.03 M Sm(NO3)3 and 0.02 M ethylenediamine, left to stand for 2 hours, then removed, washed with deionized water and dried. The Sm loading in the carrier was found to be 0.11 wt%.

[0101] S3. Place the support treated in S2 in a 0.1 M Pd(NO3)2 solution, let it stand for 1 hour, take it out, wash it with deionized water and let it dry naturally to obtain the target catalyst.

[0102] SEM images of the catalyst before and after impregnation, as shown below Figure 7 As shown. By Figure 7 It is evident that the introduction of Pd transforms the disordered and agglomerated nanosphere network structure of the Fe-based catalyst into a well-dispersed, regular nanosphere structure. Electrochemical tests show that this catalyst exhibits excellent HER and OER catalytic activity: HER overpotential η 10 =75 mV, OER overpotential η 10 =262 mV. ICP testing showed that the catalyst contained 0.65 wt% Pd and 0.11 wt% Sm.

[0103] Example 7: This Example 7 describes a multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst, prepared from the following raw materials in parts by weight:

[0104] Carrier: 6.0 parts of metal salt (Co(NO3)2);

[0105] Rare Earth Regulation Center: 0.1 parts rare earth precursor (Eu(NO3)3), 3.0 parts complexing agent (citric acid);

[0106] Noble metal active center: 1.0 part of noble metal precursor (IrCl3);

[0107] Conductive substrate: 1 piece of carbon cloth (0.5 × 0.6 cm);

[0108] The preparation steps of the multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst in this embodiment are as follows:

[0109] S1. A carbon cloth with a size of 0.5 cm × 0.6 cm was cut as the working electrode, a platinum wire as the counter electrode, and a saturated calomel electrode as the reference electrode. The three-electrode system was placed together in a 0.075 M Co(NO3)2 electrolyte and electrodeposited at a voltage of -1 V for 8 minutes. The resulting sample was washed with deionized water and then air-dried to obtain a Co(OH)2 defect carrier.

[0110] S2. Immerse the Co(OH)2 defect carrier in a mixed solution of 0.02 M Eu(NO3)3 and 0.04 M citric acid, let it stand for 2 hours, then take it out, wash it with deionized water and dry it.

[0111] S3. The support treated in S2 was placed in a mixed solution of 0.2 mM IrCl3 and 2 mM ethylenediamine and immersed for 4 hours. The zeta potential was monitored in real time during the process. After the process, the support was washed with deionized water and dried to obtain the Ir single-atom modified Co(OH)2 catalyst.

[0112] The STEM-HAADF characterization of the catalyst is as follows: Figure 8 As shown, isolated Ir single atoms can be clearly observed; electrochemical tests indicate that the catalyst exhibits excellent HER and OER catalytic activity: HER overpotential η 10 =43 mV, OER overpotential η 10 =186mV. ICP testing showed that the catalyst contained 0.91wt% Ir and 0.09wt% Eu.

[0113] Example 8: This Example 8 presents a multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst, prepared from the following raw materials in parts by weight:

[0114] Support: 3.0 parts of metal salt (Ni(NO3)2);

[0115] Rare Earth Regulation Center: 0.15 parts rare earth precursor (Gd(NO3)3), 1.7 parts coordination agent (ethylenediamine);

[0116] Noble metal active center: 2.0 parts of noble metal precursor (H2PtCl6);

[0117] Conductive substrate: 1 piece of carbon cloth (0.5 × 0.6 cm);

[0118] The preparation steps of the multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst in this embodiment are as follows:

[0119] S1. A carbon cloth with a size of 0.5 cm × 0.6 cm was cut as the working electrode, a platinum wire as the counter electrode, and a saturated calomel electrode as the reference electrode. The three electrode system was placed together in a mixed solution of 0.05 M Ni(NO3)2 and 0.02 M Ce(NO3)3 and electrodeposited at -1 V for 8 minutes. The resulting sample was washed with deionized water and then calcined in air at 300 °C for 2 hours to obtain a Ni(OH)2 defect support.

[0120] S2. Immerse the Ni(OH)2 defect carrier in a mixed solution of 0.03 M Gd(NO3)3 and 0.03 M ethylenediamine, let it stand for 2.5 hours, take it out, wash it with deionized water and dry it.

[0121] S3. The support treated in S2 was placed in a mixed solution of 0.05 M H2PtCl6 and 1 wt% polyvinylpyrrolidone and allowed to stand for 2 hours for impregnation. Then the support was placed in a N2 atmosphere and calcined at 900℃. After cooling, a Pt single-atom and NiO composite catalyst was obtained.

[0122] The STEM-HAADF characterization of the catalyst is as follows: Figure 9 As shown, isolated Pt single atoms can be clearly observed. Electrochemical tests indicate that this catalyst exhibits excellent HER catalytic activity in acidic systems: HER overpotential η 10 =23mV. ICP testing showed that the catalyst contained 0.75wt% Pt and 0.15wt% Gd.

[0123] Example 9: This Example 9 presents a multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst, prepared from the following raw materials in parts by weight:

[0124] Carrier: 3.0 parts of metal salt (Co(NO3)2), 2.0 parts of rare earth salt (La(NO3)3);

[0125] Rare Earth Regulation Center: 0.1 parts rare earth precursor (La(NO3)3), 1.9 parts complexing agent (citric acid);

[0126] Noble metal active center: 2.0 parts of noble metal precursor (H2PtCl6);

[0127] Conductive substrate: 1 sheet of titanium foam (0.6 × 0.6 cm);

[0128] The preparation steps of the multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst in this embodiment are as follows:

[0129] S1. A piece of titanium foam with a size of 0.6 cm × 0.6 cm was cut as a substrate and placed in a mixed solution of 0.1 M Co(NO3)2 and 0.3 M La(NO3)3. The mixture was hydrothermally reacted at 120 °C for 4 hours. The resulting sample was washed with deionized water and then calcined in air at 200 °C for 1 hour to obtain a Co(OH)2-La(OH)3 composite defect carrier.

[0130] S2. The Co(OH)2-La(OH)3 composite defect carrier was immersed in a mixed solution of 0.02M La(NO3)3 and 0.03M citric acid (pH=3) for 3 hours. After immersion, it was washed with deionized water and dried. The total La loading in the carrier was found to be 0.21 wt%.

[0131] S3. The support treated in S2 was immersed in 0.01 M H2PtCl6 solution, the Zeta potential was monitored in real time, and the pH was dynamically adjusted to 2.5. After the loading was completed, it was washed with deionized water and dried to obtain the Pt-La synergistic supported Co(OH)2-La(OH)3 composite support catalyst.

[0132] The acidic OER polarization curve of the catalyst is as follows: Figure 10 As shown. Electrochemical tests indicate that this catalyst exhibits excellent OER catalytic activity in acidic systems: OER overpotential η 10 =246 mV. ICP testing showed that the catalyst contained 0.38 wt% Pt and 0.21 wt% La.

[0133] Example 10: This Example 10 describes a multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst, prepared from the following raw materials in parts by weight:

[0134] Carrier: 7.0 parts of metal salt (Co(NO3)2), 0.8 parts of rare earth salt (La(NO3)3);

[0135] Noble metal active center: 6.0 parts of noble metal precursor (AgNO3), 2.0 parts of reducing agent (sodium borohydride);

[0136] Conductive substrate: 1 piece of carbon cloth (0.5 × 0.6 cm);

[0137] The preparation steps of the multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst in this embodiment are as follows:

[0138] S1. A carbon cloth with a size of 0.5 cm × 0.6 cm was cut as the working electrode, a platinum wire as the counter electrode, and a saturated calomel electrode as the reference electrode. The three-electrode system was placed in a mixed solution of 0.075 M Co(NO3)2 and an appropriate amount of La(NO3)3, and electrodeposited at -1 V for 8 min. The resulting sample was washed with deionized water and then air-dried to obtain a La-regulated Co(OH)2 defect support.

[0139] S2. The La-regulated Co(OH)2 defective support was immersed in 0.1 M AgNO3 solution, the Zeta potential was monitored in real time, the pH of the solution was dynamically adjusted to 4.2, and then 0.1 M sodium borohydride reducing agent was added dropwise at a rate of 0.3 mL / min.

[0140] S3. After the reaction is complete, the support is washed with deionized water and dried to obtain the Ag single atom and Co(OH)2 composite catalyst.

[0141] The stability test curve of the catalyst is as follows: Figure 11 As shown. By Figure 11 It can be seen that the catalyst at -1000 mA·cm -2 It can operate stably for 900 hours at industrial-grade current densities with an activity decay rate of less than 7%, demonstrating excellent long-term stability. ICP testing shows that the catalyst contains 0.85 wt% Ag and 0.10 wt% La.

[0142] Comparative Example 1: The catalyst of Comparative Example 1 was prepared from the following raw materials in parts by weight:

[0143] Support: 2.5 parts of metal salt (Ni(NO3)2);

[0144] Conductive substrate: 1 piece of carbon cloth (0.5×0.6cm);

[0145] The catalyst preparation steps in this comparative example are as follows:

[0146] A carbon cloth with a size of 0.5 cm × 0.6 cm was used as the working electrode, a platinum wire as the counter electrode, and a saturated calomel electrode as the reference electrode. The three electrode system was placed together in a 0.05 M Ni(NO3)2 solution and electrodeposited at a voltage of -1 V for 8 minutes. The resulting sample was washed with deionized water and then air-dried to obtain the Ni(OH)2 catalyst.

[0147] The XRD pattern of the catalyst is as follows: Figure 12 As shown, ICP testing indicates that the elemental content of Ni is 7.827 wt%.

[0148] Comparative Example 2: The catalyst of Comparative Example 2 was prepared from the following raw materials in parts by weight:

[0149] Carrier: 3.75 parts of metal salt (Co(NO3)2);

[0150] Conductive substrate: 1 piece of carbon cloth (0.5 × 0.6 cm);

[0151] The catalyst preparation steps in this comparative example are as follows:

[0152] A carbon cloth with a size of 0.5 cm × 0.6 cm was used as the working electrode, a platinum sheet as the counter electrode, and a saturated calomel electrode as the reference electrode. The three electrode system was placed together in a 0.075 M Co(NO3)2 solution and electrodeposited at a voltage of -1 V for 8 minutes. The resulting sample was washed with deionized water and then air-dried to obtain the Co(OH)2 catalyst.

[0153] The stability test curve of the catalyst is as follows: Figure 13 As shown, the synthesized catalyst operates at -100 mA·cm⁻¹ -2 After operating at an industrial-grade current density for 50 hours, the activity decayed by 16.6%. ICP testing showed that the elemental content of Co was 6.712 wt%.

[0154] Performance testing

[0155] 1. Linear Scan Voltammetry (LSV) Test

[0156] A three-electrode system was used for testing: the prepared catalyst was used as the working electrode, and graphite paper as the counter electrode; Hg / HgO was used as the reference electrode in 1 M MKOH alkaline solution, Ag / AgCl was used as the reference electrode in 1 M PBS buffer solution, and mercurous sulfate was used as the reference electrode in 0.5 M H2SO4 acidic solution. The HER and OER overpotentials of the catalyst were evaluated by the LSV method.

[0157] Table 1 LSV test data for different samples

[0158]

[0159] 2. Element content test

[0160] The catalyst samples prepared in the examples and comparative examples were vacuum dried to constant weight. An appropriate amount of sample was accurately weighed and microwave digested with a nitric acid-hydrochloric acid mixed acid solution. After the sample was completely digested and cooled to room temperature, it was diluted with deionized water. The noble metal elements and rare earth elements in the digestion solution were quantitatively determined by inductively coupled plasma optical emission spectrometry (ICP-OES), and the mass fraction of each element in the catalyst was calculated.

[0161] Table 2. Test data of elemental content in different samples

[0162]

[0163] Based on the above test data, we can conclude that:

[0164] 1. The comparison results of Examples 1-10 and Comparative Examples 1-2 show that the present invention adopts a three-in-one synergistic design strategy of defect support construction, rare earth element regulation, and noble metal active component loading. Under the condition of ultra-low noble metal loading (0.1-1.8wt%), the HER and OER catalytic activities of the catalyst are increased by 2-8 times compared with pure hydroxide support, which effectively solves the technical problem that traditional catalysts are difficult to simultaneously achieve high activity and high stability under low loading.

[0165] 2. The single-atom catalysts prepared in Examples 7 and 8 exhibited the best HER catalytic performance, demonstrating that through dynamic potential feedback regulation and strong anchoring effect of defect supports, efficient dispersion and stable loading of noble metal single atoms can be achieved, significantly improving atom utilization efficiency.

[0166] 3. The test results of Example 10 confirm that the synergistic effect of rare earth elements and noble metals effectively optimizes the electronic structure of the catalyst and significantly improves its long-term operational stability. The catalyst at 100 mA·cm⁻¹... -2 After 900 hours of continuous operation, the activity decay rate is less than 7%, demonstrating excellent long-term stability.

[0167] 4. The catalyst of this invention exhibits excellent electrocatalytic performance in various electrolyte systems, including alkaline, neutral, and acidic systems, verifying that the technical solution has good versatility and breaking through the application limitations of traditional catalysts in a single applicable system.

[0168] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst, characterized in that, It includes a conductive substrate, a nanostructured support layer grown on the conductive substrate, a noble metal active center and a rare earth regulation center loaded on the support layer; The support layer is a transition metal or rare earth metal oxide / hydroxide defect support with oxygen vacancies; the noble metal active center, rare earth regulatory center and support defect center form a "main-auxiliary" synergistic catalytic system through electronic interaction; The catalyst is prepared from the following raw materials in parts by weight: Carrier: 2.5-37.5 parts of metal salt; when using in-situ doping process, add an additional 0.5-2.5 parts of rare earth salt for in-situ doping; Rare Earth Regulation Center: 0.05-0.2 parts rare earth precursor, 1.5-3.0 parts complexing agent; Precious metal active center: 1-6 parts of precious metal precursor, 0.5-2.0 parts of reducing agent; The metal salts, rare earth precursors, and noble metal precursors mentioned herein are all water-soluble inorganic salts.

2. The multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst according to claim 1, characterized in that, The ligand is selected from one or more nitrogen-containing organic ligands or inorganic ammonium salts; the noble metal precursor is selected from one or more of ruthenium trichloride, chloroplatinic acid, palladium nitrate, iridium trichloride, chloroauric acid, and silver nitrate; the reducing agent is selected from one or two of sodium borohydride and potassium borohydride.

3. A method for preparing a multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst, used to prepare the multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst described in claims 1-2, characterized in that, The specific preparation method is as follows: S1. On a pretreated conductive substrate, oxide / hydroxide supports of transition metals or rare earth metals are prepared by electrodeposition, hydrothermal method or chemical plating, and then defect supports with oxygen vacancies are constructed by in-situ doping or calcination. S2. The defect support of S1 is immersed in a solution containing rare earth precursors and ligands. Rare earth elements are loaded onto the support in the form of lattice doping or surface modification through coordination-hydrolysis reaction. The rare earth loading is 0.05-1 wt%. S3. The carrier of S2 is immersed in a solution of the noble metal precursor. By monitoring the zeta potential in real time, the solution pH and the reducing agent dropping rate are dynamically adjusted to disperse the noble metal near the rare earth control center. The noble metal loading is 0.1-1.8 wt%. S4. The product of S3 is washed, dried or calcined to obtain a multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst.

4. The method for preparing a multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst according to claim 3, characterized in that, In step S1, the conductive substrate is one or more of carbon fiber material, titanium mesh, molybdenum mesh, foam metal and composite nickel mesh; the transition metal is one or more of nickel, cobalt, iron, copper and manganese; and the rare earth metal is one or more of lanthanum, cerium, praseodymium, neodymium, samarium, europium and gadolinium.

5. The method for preparing a multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst according to claim 3, characterized in that, In step S1, in-situ doping involves adding 0.01-0.05 M rare earth salt during the preparation of the support; calcination involves annealing at 200-400℃ for 2-4 hours under an inert atmosphere.

6. The method for preparing a multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst according to claim 3, characterized in that, The process parameters for electrodeposition, hydrothermal plating, and electroless plating in step S1 are as follows: Electrodeposition method: Using a conductive substrate as the working electrode, deposition is carried out for 5-60 minutes at a constant voltage of -0.8 V to -1.4 V (vs. SCE); Hydrothermal method: reaction temperature 100-150 ℃, reaction time 2-24 hours; Chemical plating: Temperature 50-100 ℃, time 0.5-6 hours.

7. The preparation method of a multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst according to claim 3, characterized in that, In steps S2 and S3, the concentration of the precursor solution is 0.01 M-0.2 M, the target value of the Zeta potential in step S3 is -20 to -40 mV, the pH of the reaction solution is adjusted to 2-8, and the dropping rate of the reducing agent is 0.1-0.5 mL / min.

8. The method for preparing a multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst according to claim 3, characterized in that, The vacuum drying conditions in step S4 are 50-70 ℃ for 10-14 hours, and the calcination conditions are 300-900 ℃ for 1-3 hours.

9. The application of the multifunctional synergistic composite ultra-low-loaded noble metal-rare earth catalyst according to claims 1-2, characterized in that, The catalyst serves as an electrocatalyst for hydrogen evolution and / or oxygen evolution reactions, and is suitable for acidic, alkaline, or neutral electrolyte systems.

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