Ce-Co supported Co3O4 nanoneedle array catalyst, its preparation and application in acidic water electrolysis.
CoCe-Co3O4 nanoneedle array catalysts were prepared by solvothermal and pyrolysis methods, which solved the stability and activity problems of Co3O4 materials in acidic water electrolysis and realized the efficient electrocatalytic oxygen desorption reaction of water.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-04-15
- Publication Date
- 2026-06-05
Smart Images
Figure CN122147425A_ABST
Abstract
Description
Technical Field
[0001] This invention discloses a method for preparing a catalyst (CoCe-Co3O4 NNAs) based on a heterostructure of Ce-doped Co3O4 nanoparticles and Co3O4 nanoneedle arrays, and the application of this catalyst in the field of acidic water electrolysis, belonging to the fields of electrochemical technology, hydrogen energy and catalytic materials. Background Technology
[0002] With the overexploitation and consumption of traditional fossil fuels, the resulting energy shortages and ecological degradation have become increasingly severe, making the development of green and low-carbon alternative energy sources a global consensus. Hydrogen energy, with its high calorific value, pollution-free products, and wide availability, is considered an important vehicle for future energy structure transformation. Among various hydrogen production pathways, proton exchange membrane electrolysis (PMMWE) has attracted widespread attention from industry and academia due to its ability to couple with the fluctuations of renewable energy sources (such as wind and solar power), its operational flexibility, and its high-purity gas production. However, the large-scale commercial application of this technology is limited by the slow four-electron transfer process of the oxygen evolution reaction (OER), which requires a high overpotential to drive, leading to a decrease in overall energy efficiency. Currently, Ir and Ru-based noble metal oxides are recognized as excellent OER electrocatalysts under acidic conditions, but their abundance in the Earth's crust is extremely low, their price is high, and they are prone to dissolution and aggregation during long-term operation, making it difficult to meet the needs of sustainable development. Therefore, exploring non-noble metal-based acidic oxygen evolution reaction (AOER) electrocatalysts that combine high activity and high stability is of great strategic significance for promoting the practical application of PMMWE.
[0003] Spinel-phase Co3O4 materials in transition metal oxides are considered potential candidates to replace noble metal catalysts due to their high atom economy, strong redox reversibility, and simple preparation process. However, under extreme conditions of strong acidity and high oxidation potential (>1.4 V vs. RHE), the cobalt species on the surface of spinel-phase Co3O4 easily undergo disproportionation reactions to generate easily soluble CoO2, leading to catalyst structural collapse and rapid loss of activity. This severely restricts its direct application in PEM water electrolysis. Currently, spinel-phase Co3O4 materials still face multiple challenges in AOER applications: difficulty in controlling active sites; poor mechanical and chemical stability under strong acid conditions; and high preparation costs, all of which greatly limit their performance as electrocatalysts. Summary of the Invention
[0004] To address the problems existing in the prior art, the present invention aims to propose a simple, inexpensive, and readily available method for preparing a CoCe-Co3O4 NNAs water electrolysis catalyst under mild reaction conditions. CoCe-Co3O4 NNAs exhibit high activity, good stability, small size, customizable chemical composition, good conductivity, and low cost, demonstrating significant application potential. This method improves the activity and stability of the electrocatalytic water splitting reaction.
[0005] The technical solution adopted in this invention is as follows: a method for preparing an acidic water electrolysis electrocatalytic electrode material of Ce-doped Co3O4 nanoparticle-supported Co3O4 nanoneedle array composite material, specifically including the following steps:
[0006] (1) Clean the conductive carbon paper substrate and dry it;
[0007] (2) Dissolve water-soluble cobalt salt, ammonium fluoride and urea in deionized water and stir until homogeneous to obtain a homogeneous mixed solution;
[0008] The molar ratio of the water-soluble cobalt salt, ammonium fluoride, and urea is 1:(2-4):(3-5);
[0009] (3) Transfer the mixture to a Teflon-lined stainless steel reactor, place the conductive substrate vertically into the reactor, then seal the reactor and keep it at 100~130℃ for 8-12 hours;
[0010] (4) After the reactor is naturally cooled, the conductive substrate is removed, washed and dried to obtain a conductive substrate loaded with Co(OH)F NNAs;
[0011] (5) Take water-soluble cobalt salt and water-soluble cerium salt and add them to deionized water. Stir at room temperature until completely dissolved to obtain a homogeneous mixed solution;
[0012] The molar ratio of water-soluble cobalt salt to water-soluble cerium salt is (15-35):1;
[0013] (6) The mixed solution is drop-coated onto a conductive carbon paper substrate and then dried.
[0014] (7) Transfer the loaded conductive substrate to a tube furnace and anneal it at 300-500℃ for 1-12 hours;
[0015] (8) After the reaction is complete, take it out after natural cooling, clean it, and vacuum dry it to obtain the electrocatalytic electrode material.
[0016] Furthermore, the water-soluble cobalt salt is selected from one or more of cobalt chloride, cobalt nitrate, cobalt sulfate, cobalt acetate, and cobalt bromide; the water-soluble cerium salt is selected from one or more of cerium chloride, cerium nitrate, cerium sulfate, and cerium acetate.
[0017] Furthermore, the water-soluble cobalt salt is cobalt nitrate hexahydrate, and the water-soluble cerium salt is cerium nitrate hexahydrate.
[0018] Furthermore, in step (2), the concentration of cobalt nitrate hexahydrate in the mixed solution is 0.03~0.05 M, the concentration of ammonium fluoride is 0.05~0.15 M, and the concentration of urea is 0.05~0.2 M.
[0019] Furthermore, in step (5), the concentration of cobalt nitrate hexahydrate in the mixed solution is 0.1~0.5 M, and the concentration of cerium nitrate hexahydrate is 0.025~0.25 M.
[0020] An electrocatalytic electrode material is prepared using the method described above.
[0021] The electrocatalytic electrode material is used in the electrocatalytic desorption of oxygen reaction.
[0022] Preferably, the electrocatalytic electrode material is used in an acidic electrocatalytic water desorption oxygen reaction.
[0023] Furthermore, in the standard three-electrode system, Ag / AgCl is used as the reference electrode, platinum wire as the counter electrode, and the electrocatalytic electrode material as the working electrode. The electrode is placed in the electrolyte to carry out the electrocatalytic desorption of oxygen reaction.
[0024] Furthermore, the electrolyte is a 0.2-0.8 M H2SO4 solution.
[0025] The specific technical solution adopted in this application is as follows:
[0026] A method for preparing an acidic water electrolysis catalyst supported on Ce-doped Co3O4 nanoparticles and consisting of Co3O4 nanoneedle arrays includes the following steps:
[0027] (1) Clean the conductive substrate carbon paper with deionized water and ethanol, and then vacuum dry it;
[0028] (2) Place a piece of conductive carbon paper (2×3 cm) 2 The carbon paper was ultrasonically treated in a 18.4 M concentrated sulfuric acid solution for 1.5 hours to remove surface impurities and enhance the hydrophilicity of the carbon paper.
[0029] (3) Continue ultrasonic treatment in deionized water for 0.5 hours to remove residual sulfuric acid;
[0030] (4) Clean with deionized water and ethanol alternately, and then vacuum dry;
[0031] (5) Cobalt nitrate hexahydrate, ammonium fluoride and urea are dissolved in deionized water and stirred evenly to obtain a homogeneous mixed solution; the concentration of cobalt nitrate hexahydrate in the mixed solution is 0.03~0.05 M, the concentration of ammonium fluoride is 0.05~0.15 M and the concentration of urea is 0.05~0.2 M;
[0032] (6) Transfer the mixture to a Teflon-lined stainless steel reactor, place the conductive substrate vertically into the reactor, then seal the reactor and keep it at 100-130°C for 8-12 hours.
[0033] (7) After the reactor is naturally cooled, the conductive substrate is taken out, rinsed with deionized water and anhydrous ethanol, and then vacuum dried to obtain the conductive substrate loaded with Co(OH)F NNAs.
[0034] (8) Take cobalt nitrate hexahydrate and cerium nitrate hexahydrate and add them to deionized water. Stir at room temperature until completely dissolved to obtain a homogeneous mixed solution. The concentration of cobalt nitrate hexahydrate in the mixed solution is 0.1~0.5 M and the concentration of cerium nitrate hexahydrate is 0.025~0.25 M.
[0035] (9) The mixed solution is drop-coated onto a conductive carbon paper substrate and dried at 60°C;
[0036] (10) Transfer the carbon paper loaded with the material to a tube furnace and anneal it at 400°C for 2 hours.
[0037] (11) After the reaction is complete and the material is cooled naturally, it is taken out, cleaned and vacuum dried to obtain the electrocatalytic material.
[0038] This invention also provides a method for preparing a Ce-doped Co3O4 nanoparticle-supported Co3O4 nanoneedle array acidic water electrolysis electrocatalytic electrode material loaded on carbon paper. The catalyst prepared can be directly used in electrocatalytic applications. In a standard three-electrode system (Ag / AgCl as the reference electrode, platinum wire as the counter electrode, and the prepared material as the working electrode), the electrocatalytic electrode material is directly used as the working electrode and placed in 0.5 M H2SO4 electrolyte to carry out the electrocatalytic water desorption oxygen reaction.
[0039] Compared with the prior art, the present invention has the following advantages:
[0040] 1. The composite catalyst prepared in this invention first constructs a cobalt nanoarray (Co(OH)F NNAs) on an electrode substrate via a solvothermal method, and then loads Ce-doped Co3O4 nanoparticles onto the transformed Co3O4 NNAs via a pyrolysis method, thus avoiding the use of binders for drop coating, which would affect conductivity and damage the original nanostructure.
[0041] 2. The CoCe-Co3O4 NNAs material catalyst of the present invention has the following characteristics: Co3O4 nanoparticles increase the specific surface area and provide more active sites; the introduction of Ce element regulates the electronic structure and coordination environment of Co active center, promotes the adsorption and transformation of reaction intermediates, and inhibits the precipitation of active sites, thereby improving catalytic stability.
[0042] 3. Electrochemical performance is an important indicator for evaluating the quality of electrocatalysts. In an acidic 0.5 M H₂SO₄ system, CoCe-Co₃O₄ NNAs exhibit electrochemical performance at 10 mA·cm⁻¹. -2 It exhibits the lowest AOER overpotential at the specified current density, significantly superior to other comparative examples; it possesses the largest electrochemical active surface area, indicating the most active sites; it has the smallest Tafel slope, indicating the most favorable kinetics; and it displays the lowest impedance, accelerating the charge transfer process and thus the AOER reaction kinetics. At 10 mA·cm⁻¹ -2 It can operate stably for more than 90 hours at a current density.
[0043] In summary, this invention provides a method for preparing CoCe-Co3O4 NNAs electrode materials on a carbon paper substrate via solvothermal and pyrolysis methods. The preparation method is simple, and the raw materials are inexpensive and readily available. The prepared electrode materials have significant advantages in acidic electrocatalytic water splitting reactions, and the prepared catalyst exhibits low overpotential and high stability in the AOER process. Attached Figure Description
[0044] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below.
[0045] Figure 1 X-ray diffraction patterns of the prepared cobalt-based electrocatalysts Co3O4 NNAs, Co-Co3O4 NNAs, Ce-Co3O4 NNAs, and CoCe-Co3O4NNAs.
[0046] Figure 2 In the image, a is a scanning electron microscope (SEM) image of the Co3O4 NNAs prepared in the first step, and b is a scanning electron microscope (SEM) image of the prepared CoCe-Co3O4 NNAs electrocatalyst.
[0047] Figure 3 In Figure a, LSV curves of the prepared CoCe-Co3O4 NNAs electrocatalyst and the control sample are shown; in Figure b, Tafel slopes of the prepared CoCe-Co3O4 NNAs electrocatalyst and the control sample are shown.
[0048] Figure 4The CV curves of the prepared CoCe-Co3O4 NNAs electrocatalyst and the control sample are shown.
[0049] Figure 5 The electrochemical active surface areas of the prepared CoCe-Co3O4 NNAs electrocatalyst and the control sample are shown.
[0050] Figure 6 EIS spectra of the prepared CoCe-Co3O4 NNAs electrocatalyst and the control sample at different potentials.
[0051] Figure 7 The image shows the test results of the prepared CoCe-Co3O4 NNAs electrocatalyst and the control sample.
[0052] Figure 8 Comparison of X-ray diffraction patterns before and after stability testing of CoCe-Co3O4 NNAs electrocatalyst.
[0053] Figure 9 This is a scanning electron microscope image of the CoCe-Co3O4 NNAs electrocatalyst after stability testing. Detailed Implementation
[0054] To make the present invention concise and easy to understand, the following embodiments are preferred, and detailed descriptions are provided in conjunction with the accompanying drawings. Unless otherwise specified, all raw materials are available from publicly available commercial sources.
[0055] Example 1: A method for preparing an acidic water electrocatalytic electrode material for water splitting supported on Ce-doped Co3O4 nanoparticles and Co3O4 nanoneedle arrays.
[0056] (1) Clean the conductive substrate carbon paper with deionized water and ethanol, and then vacuum dry it;
[0057] (2) Place a piece of conductive carbon paper (2×3 cm) 2 The carbon paper was ultrasonically treated in a 18.4 M concentrated sulfuric acid solution for 1.5 hours to remove surface impurities and enhance the hydrophilicity of the carbon paper.
[0058] (3) Continue ultrasonic treatment in deionized water for 0.5 hours to remove residual sulfuric acid;
[0059] (4) Clean with deionized water and ethanol alternately, and then vacuum dry;
[0060] (5) Dissolve 1.5 mmol cobalt nitrate hexahydrate, 4.5 mmol ammonium fluoride and 6 mmol urea in 30 mL of deionized water and stir for 10 min until completely dissolved;
[0061] (6) Transfer the mixture to a Teflon-lined stainless steel reactor, vertically place the conductive carbon paper substrate into the reactor, then seal the reactor and keep it at 120°C for 8 hours.
[0062] (7) After the reactor is naturally cooled, the conductive substrate is taken out and rinsed three times with deionized water and anhydrous ethanol. After vacuum drying, the conductive substrate loaded with Co(OH)F NNAs is obtained.
[0063] (8) Take 0.2375 mmol of cobalt nitrate hexahydrate and 0.0125 mmol of cerium nitrate hexahydrate and add them to 0.5 mL of deionized water. Stir at room temperature until completely dissolved to obtain a homogeneous mixed solution.
[0064] (9) The mixed solution is drop-coated onto a conductive carbon paper substrate and dried at 60°C;
[0065] (10) Transfer the carbon paper loaded with the material to a tube furnace and anneal it at 400°C for 2 hours.
[0066] (11) After the reaction is complete and the mixture is cooled naturally, it is taken out, washed and vacuum dried to obtain the CoCe-Co3O4 NNAs catalyst.
[0067] Comparative example Co3O4
[0068] The method of Example 1 was used, except that no reagent was added when preparing the (8) mixed solution, only 0.5 mL of deionized water was added, and other conditions remained unchanged.
[0069] Comparative example Co-Co3O4
[0070] Using the method of Example 1, only 0.25 mmol of cobalt nitrate hexahydrate was added when preparing the (8) mixed solution, while other conditions remained unchanged.
[0071] Comparative example Ce-Co3O4
[0072] The method of Example 1 was used, except that 0.25 mmol of cerium nitrate hexahydrate was added when preparing the (8) mixed solution, while other conditions remained unchanged.
[0073] Example 2 Application of water electrolysis catalyst
[0074] The application of the CoCe-Co3O4 NNAs catalyst from Example 1 in electrocatalytic water splitting (OER) follows these steps:
[0075] (1) Preparation of working electrode
[0076] The prepared dried CoCe-Co3O4 NNAs were cut into 1 × 1 cm pieces. 2In a three-electrode system, it is used as the anode, Pt wire as the cathode, and Ag / AgCl electrode as the reference electrode.
[0077] (2) Electrocatalytic oxygen evolution reaction
[0078] All electrochemical tests were performed at room temperature using a three-electrode system, with a Pt wire as the cathode, an Ag / AgCl electrode as the reference electrode, and the prepared catalyst and control sample as the anode. 0.5 M H₂SO₄ was used as the electrolyte for the electrochemical tests. Prior to the electrochemical OER tests, the electrodes were activated by CV (conductively coupled plasma optical emission measurement) for 10 cycles at a scan rate of 50 mV·s. -1 .
[0079] Example 3
[0080] (1) Phase characterization of CoCe-Co3O4 NNAs
[0081] The prepared CoCe-Co3O4 NNAs, Co-Co3O4 NNAs, Ce-Co3O4 NNAs, and Co3O4 NNAs were directly applied to characterization and analysis processes such as X-ray diffraction (XRD) and scanning electron microscopy (SEM). Figure 1 The XRD patterns show that the CoCe-Co3O4 NNAs, Co-Co3O4 NNAs, and Co3O4 NNAs catalysts are well matched with the spinel phase Co3O4 standard card PDF#42-1467. The CoCe-Co3O4 NNAs show a slight shift towards the lower diffraction angle, indicating successful Ce doping.
[0082] Figure 2 SEM images of the synthesized CoCe-Co3O4 NNAs loaded on carbon paper are shown, indicating that the Co3O4 NNAs are a nanoarray uniformly coated on the carbon paper fibers, and Ce-doped Co3O4 nanoparticles are attached to the Co3O4 NNAs.
[0083] (2) Electrochemical testing of CoCe-Co3O4 NNAs
[0084] Electrochemical performance is an important indicator for evaluating the quality of electrocatalysts. Figure 3 As shown in (a), the LSVs can be observed at 10 mA·cm⁻¹. -2 and 100 mA·cm -2 The overpotentials were 356 and 435 mV, respectively, which were significantly better than those of the comparative examples (Co-Co3O4, Ce-Co3O4, Co3O4). Figure 3(b)CoCe-Co3O4 NNAs have the smallest Tafel slope, at 56.77 mV·dec -1 This indicates a relatively fast OER kinetic process. Figure 5 Among them, CoCe-Co3O4 NNAs have the largest active surface area (1.28 mF cm⁻¹). -2 This indicates that CoCe-Co3O4 NNAs have a richer number of active sites. Figure 6 In the diagram, it can be seen that CoCe-Co3O4 NNAs have the lowest impedance. Figure 7 The CoCe-Co3O4 NNAs were shown to have stability of over 90 hours. Figure 8 The results showed that the crystal form of CoCe-Co3O4 NNAs did not change significantly after the reaction, but the peak intensity decreased slightly. Figure 9 The reaction showed that the morphology of the CoCe-Co3O4 NNAs catalyst did not change significantly after the reaction, demonstrating excellent OER performance and potential application value.
[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; 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 or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for preparing an acidic water electrocatalytic electrode material for electrolysis using Ce-doped Co3O4 nanoparticles supported on a Co3O4 nanoneedle array composite material, characterized in that... Includes the following steps: (1) Clean the conductive carbon paper substrate and dry it; (2) Dissolve water-soluble cobalt salt, ammonium fluoride and urea in deionized water and stir until homogeneous to obtain a homogeneous mixed solution; The molar ratio of the water-soluble cobalt salt, ammonium fluoride, and urea is 1:(2-4):(3-5); (3) Transfer the mixture to a Teflon-lined stainless steel reactor, place the conductive substrate vertically into the reactor, then seal the reactor and keep it at 100~130℃ for 8-12 hours; (4) After the reactor is naturally cooled, the conductive substrate is removed, washed and dried to obtain a conductive substrate loaded with Co(OH)F NNAs; (5) Take water-soluble cobalt salt and water-soluble cerium salt and add them to deionized water. Stir at room temperature until completely dissolved to obtain a homogeneous mixed solution; The molar ratio of water-soluble cobalt salt to water-soluble cerium salt is (15-35):1; (6) The mixed solution is drop-coated onto a conductive carbon paper substrate and then dried. (7) Transfer the loaded conductive substrate to a tube furnace and anneal it at 300-500℃ for 1-12 hours; (8) After the reaction is complete, take it out after natural cooling, clean it, and vacuum dry it to obtain the electrocatalytic electrode material.
2. The method for preparing an acidic water electrolytic electrocatalytic electrode material for Ce-doped Co3O4 nanoparticle-supported Co3O4 nanoneedle array composite material according to claim 1, characterized in that: The water-soluble cobalt salt is selected from one or more of cobalt chloride, cobalt nitrate, cobalt sulfate, cobalt acetate, and cobalt bromide; the water-soluble cerium salt is selected from one or more of cerium chloride, cerium nitrate, cerium sulfate, and cerium acetate.
3. The method for preparing an acidic water electrolytic electrocatalytic electrode material for Ce-doped Co3O4 nanoparticle-supported Co3O4 nanoneedle array composite material according to claim 1, characterized in that: The water-soluble cobalt salt is cobalt nitrate hexahydrate, and the water-soluble cerium salt is cerium nitrate hexahydrate.
4. The method for preparing an acidic water electrolytic electrocatalytic electrode material for Ce-doped Co3O4 nanoparticle-supported Co3O4 nanoneedle array composite material according to claim 3, characterized in that: In step (2), the concentration of cobalt nitrate hexahydrate in the mixed solution is 0.03~0.05 M, the concentration of ammonium fluoride is 0.05~0.15 M, and the concentration of urea is 0.05~0.2 M.
5. The method for preparing an acidic water electrolysis electrocatalytic electrode material of Ce-doped Co3O4 nanoparticle-supported Co3O4 nanoneedle array composite material according to claim 4, characterized in that: In step (5), the concentration of cobalt nitrate hexahydrate in the mixed solution is 0.1~0.5 M, and the concentration of cerium nitrate hexahydrate is 0.025~0.25 M.
6. An electrocatalytic electrode material, characterized in that: It is prepared by the preparation method described in any one of claims 1-5.
7. The application of the electrocatalytic electrode material according to claim 6, characterized in that: The electrocatalytic electrode material is used in the electrocatalytic desorption of oxygen reaction.
8. The application of the electrocatalytic electrode material according to claim 7, characterized in that: The electrocatalytic electrode material is used in the acidic electrocatalytic desorption oxygen reaction of water.
9. The application according to claim 8, characterized in that: In the standard three-electrode system, Ag / AgCl is used as the reference electrode, platinum wire as the counter electrode, and the electrocatalytic electrode material is used as the working electrode. The electrode is placed in the electrolyte to carry out the electrocatalytic desorption of oxygen reaction.
10. The application according to claim 9, characterized in that: The electrolyte is a 0.2-0.8 M H2SO4 solution.