Manganese-based oxybromide-tungsten oxide composite material as well as preparation method and application thereof
By preparing manganese-based bromide oxide-tungsten oxide composite materials, the problem of poor activity and stability of non-precious metal catalysts under acidic conditions is solved, and efficient electrocatalytic water decomposition and cost reduction effect is achieved. It is suitable for industrial hydrogen production devices.
Patent Information
- Application Number
- CN202510769509.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-10
- Publication Date
- 2025-09-02
AI Technical Summary
In the prior art, non-precious metal catalysts have poor catalytic activity and stability under acidic conditions, and the precious metal-based catalysts are expensive, resulting in low efficiency of the electrolytic water device.
A manganese-based bromide oxide-tungsten oxide composite material was prepared, and a polycrystalline crystal structure was formed by adsorbing manganese halide and manganese-based inorganic salt precursor on the conductive substrate, and calcining at high temperature and vacuum burning.
In an acidic environment, it significantly reduces the overpotential, improves catalytic activity and stability, and reduces costs. It is suitable for PEM electrolytic cells of industrial hydrogen production devices.
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Figure CN120575255A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of electrocatalytic materials, and in particular relates to a manganese-based oxybromide-tungsten oxide composite material and a preparation method and application thereof. Background Art
[0002] With the increasing depletion of fossil energy resources and the increasing prominence of environmental issues, traditional fossil energy can no longer meet people's energy needs. In this context, technologies such as electrocatalytic water splitting to produce hydrogen, electrocatalytic carbon dioxide reduction, and electrocatalytic nitrogen reduction have become important ways to replace traditional fossil energy, reduce carbon emissions, and obtain renewable energy. To achieve these electrocatalytic energy conversions, the oxygen evolution reaction (OER) is crucial. During the OER process, two oxygen atoms in two water molecules combine and release an oxygen molecule, providing the protons and electrons required for hydrogen generation, electrochemical carbon dioxide reduction, and nitrogen fixation. However, the multi-electron transfer OER process involves multiple reaction intermediates and requires a high overpotential to overcome the slow kinetics. Therefore, researching and developing efficient catalysts to reduce energy consumption and improve efficiency in the OER process is key to promoting the commercial application of electrocatalytic energy conversion technology.
[0003] Proton exchange membrane (PEM)-based PEM electrolyzers have significant advantages over alkaline electrolyzers, including more compact system design, lower ohmic losses, higher current density and gas purity, a larger partial load range, and faster system response speed. However, the perfluorosulfonic acid membrane used in PEM forms a local acidic environment with a pH of 0-3 in water, requiring corrosion-resistant components and increasing costs. In addition, the choice of anode catalyst is also subject to many limitations. Most precious metal and non-precious metal-based catalysts only show high activity and stability in alkaline electrolytes. Currently, only metal iridium oxide and ruthenium-based materials can achieve a balance of activity and stability in acidic electrolytes, but they are expensive and difficult to apply on a large scale. Therefore, the development of non-precious metal OER catalysts with high activity and durability in acidic media is crucial to improving the efficiency of PEM devices and reducing operating costs.
[0004] It is a challenging task to effectively control the surface self-reconstruction effect of the material in the electrochemical oxygen evolution process under acidic conditions and to ensure that the stability of the material is not sacrificed during the process of optimizing the catalytic activity. MnO2, as a non-precious metal catalyst, has structural diversity and valence diversity (for example, Mn 4+ and Mn 3+), as well as low toxicity and high storage capacity, showing stable prospects in acidic OER. However, MnO2 usually shows OER activity far lower than expected, with a high overpotential, which is attributed to its low conductivity and lack of exposed active sites. Its catalytic performance still lags behind that of precious metal catalysts, and its energy consumption is high during water electrolysis. Therefore, the development of efficient and stable manganese-based catalysts is of great significance for practical applications in the field of electrocatalysis. Summary of the Invention
[0005] To address the above technical issues, the present invention provides a manganese-based oxybromide-tungsten oxide composite material, its preparation method, and its application. The manganese-based oxybromide-tungsten oxide composite material provided by the present invention addresses the poor catalytic activity and stability of non-precious metal catalysts in acidic conditions in the prior art, as well as the high cost of prior art water electrolysis devices that rely on precious metal-based catalysts.
[0006] To achieve the above objectives, the technical solution provided by the present invention is:
[0007] In one aspect, the present invention provides a method for preparing a manganese-based oxybromide-tungsten oxide composite material, comprising the following steps:
[0008] (1) preparing a precursor solution containing manganese-based halide, manganese-based inorganic salt and tungsten trioxide;
[0009] (2) immersing a conductive substrate in the precursor solution or applying a drop of the precursor solution on a conductive substrate to obtain a conductive substrate adsorbing the precursor solution;
[0010] (3) heating the conductive substrate adsorbing the precursor solution at 160° C. to 300° C.;
[0011] (4) The conductive substrate after heat treatment is vacuum-fired.
[0012] As a preferred embodiment, in step (1), the manganese-based halide is manganese bromide tetrahydrate or manganese bromide.
[0013] And / or, in step (1), the manganese-based inorganic salt is manganese nitrate tetrahydrate or manganese nitrate.
[0014] And / or, in step (1), the solvent of the precursor solution is a mixed solvent of water and an organic solvent; the organic solvent is selected from at least one of ethanol, isopropanol, dimethylformamide, ethyl acetate, and acetone.
[0015] As a preferred embodiment, in step (1), the molar ratio of manganese in the manganese-based halide and the manganese in the manganese-based inorganic salt is 1:1-5.
[0016] And / or, in step (1), the molar ratio of manganese in the manganese-based halide and the manganese-based inorganic salt to tungsten in tungsten trioxide is 10 to 50:1.
[0017] In certain specific embodiments, in step (1), the precursor solution is prepared by dissolving a manganese-based halide in a manganese-based inorganic salt solution; and then mixing it with a tungsten trioxide solution; the solvent of the manganese-based inorganic salt solution is water; and the solvent of the tungsten trioxide solution is an organic solvent.
[0018] In certain specific embodiments, in step (1), the precursor solution further contains a doping element; the doping element is selected from at least one of ruthenium, iridium, cobalt, nickel, chromium, iron, molybdenum, bismuth, tantalum, silver, rhodium, strontium, aluminum and titanium.
[0019] As a preferred embodiment, in step (2), the conductive substrate is pretreated by acidification; the acidification is to ultrasonically treat the conductive substrate in an acid solution; the acid solution is a nitric acid solution or a hydrochloric acid solution; and the ultrasonic treatment time is 30 to 40 minutes.
[0020] In certain specific embodiments, the concentration of the nitric acid solution is 20% to 60%;
[0021] In certain specific embodiments, the concentration of the hydrochloric acid solution is 10% to 30%.
[0022] In certain specific embodiments, the conductive substrate is pre-treated by washing and drying before acidification.
[0023] Preferably, in step (2), the adsorption amount per unit area of manganese on the conductive substrate is 0.00009 to 0.0007 mol / cm 2 .
[0024] In certain specific embodiments, the conductive substrate is a carbon-based material; the carbon-based material is selected from at least one of carbon fiber cloth, carbon paper, carbon cloth, carbon felt and reticulated glassy carbon.
[0025] As a preferred embodiment, in step (3), the heating treatment time is 2 to 5 hours.
[0026] And / or, in step (4), the temperature of the vacuum burning is 200-800°C.
[0027] And / or, in step (4), the vacuum burning time is 2 to 4 hours.
[0028] In some specific embodiments, step (4) further comprises post-treatments of washing and drying.
[0029] In another aspect, the present invention provides a manganese-based oxybromide-tungsten oxide composite material obtained by the above preparation method.
[0030] In another aspect, the present invention provides use of the above-mentioned manganese-based oxybromide-tungsten oxide composite material in the preparation of an electrochemical catalyst.
[0031] Preferably, the invention is used in the preparation of oxygen evolution reaction catalyst.
[0032] Preferably, the invention is used in the preparation of an acidic electrolyte oxygen evolution reaction catalyst.
[0033] The present invention has the following advantages and effects:
[0034] The present invention provides a manganese-based oxybromide-tungsten oxide composite material, a preparation method thereof, and an application thereof. The manganese-based oxybromide-tungsten oxide composite material uses manganese-based halides and manganese-based inorganic salts as manganese sources, is prepared by adsorbing them on a conductive substrate, and then undergoing high-temperature calcination and vacuum calcination. During the preparation process, the composite material is loaded on the conductive substrate. The composite material has a polycrystalline face crystal structure, and the manganese element has multiple coordination modes.
[0035] The manganese-based oxybromide-tungsten oxide composite material provided by the present invention has multiple active sites and high stability. As an oxygen evolution reaction catalyst in an acidic environment, it can significantly reduce the overpotential and exhibit excellent stability: reaching 10 mA / cm in an acidic medium with pH = 0. 2 The overpotential required for catalytic current density is 230-250mV; 10mA / cm 2 The stable operation time at this current density exceeded 1650 hours, with an overpotential rise rate of 0.05-0.06 mV / h. The high performance of this composite material can be attributed to the structural changes caused by the introduction of WO3, which increases the electron density and overall conductivity. Furthermore, during the oxygen evolution process, the composite interface undergoes self-reconstruction to produce a Lewis base, creating a localized slightly alkaline environment. This effectively overcomes the poor performance of non-precious metal catalysts due to acidic corrosion, improving activity and stability.
[0036] The preparation method provided by this invention is simple and suitable for large-scale production. Compared with existing water electrolysis devices that rely heavily on precious metal-based catalysts, it significantly reduces costs. Therefore, this composite material is expected to be applied to PEM electrolyzers in industrial hydrogen production devices, providing technical feasibility for large-scale hydrogen production. BRIEF DESCRIPTION OF THE DRAWINGS
[0037] Figure 1 Polarization curves of the products prepared in Example 1, Comparative Example 1, and Comparative Example 2 of the present invention measured by linear sweep voltammetry (LSV) in 0.5 M H2SO4 solution at a scan rate of 1 mV / s;
[0038] Figure 2 The product prepared in Example 1 of the present invention is -2 A graph showing the relationship between operating voltage and time at constant current density. All electrode potential data in the figure are 100% iR compensated.
[0039] Figure 3 The XRD diffraction patterns of the products prepared in Example 1 and Comparative Example 1 of the present invention;
[0040] Figure 4 TEM image of the product prepared in Example 1 of the present invention;
[0041] Figure 5 、 6 This is a high-resolution transmission electron microscopy (HRTEM) image of the product prepared in Example 1 of the present invention. DETAILED DESCRIPTION
[0042] The following embodiments are merely some of the embodiments of the present invention, rather than all of them. Therefore, the detailed description of the embodiments of the present invention provided below is not intended to limit the scope of the claimed invention, but rather merely represents selected embodiments of the present invention. All other embodiments derived by those skilled in the art based on the embodiments of the present invention without creative effort are intended to fall within the scope of protection of the present invention.
[0043] In the present invention, unless otherwise specified, all equipment and raw materials can be purchased from the market or are commonly used in the industry. The methods in the following embodiments, unless otherwise specified, are all conventional methods in the art.
[0044] Example 1:
[0045] (1) 2*1cm 2 The conductive carbon cloth was sequentially immersed in acetone, anhydrous ethanol, and deionized water for 5 minutes and then dried; then placed in a 40% nitric acid solution and treated under ultrasonic conditions for 40 minutes;
[0046] (2) Dissolve 292.7 mg of manganese bromide tetrahydrate in 490 μl of 4 M manganese nitrate solution by ultrasonication; dissolve 18.5 mg of tungsten trioxide in 300 μl of anhydrous ethanol by ultrasonication; mix the above solutions and mechanically shake to obtain a precursor solution;
[0047] (3) Preheat the heating plate to 220°C; Place the pretreated conductive carbon cloth flat on the heating plate and add 200 μL of the above precursor solution drop by drop, ensuring that the precursor solution is evenly loaded on the conductive carbon cloth; After the addition is completed, maintain the temperature at 220°C for 3 hours;
[0048] (4) calcining under vacuum at 400°C for 3 hours; after cooling to room temperature, ultrasonicating in deionized water for 30 seconds and rinsing three times; drying in an oven at 60°C to obtain a manganese-based oxybromide-tungsten oxide composite material supported on a conductive carbon cloth.
[0049] Example 2:
[0050] (1) 2*1cm 2 The conductive carbon cloth was sequentially immersed in acetone, anhydrous ethanol, and deionized water for 5 minutes and then dried; then placed in a 40% nitric acid solution and treated under ultrasonic conditions for 40 minutes;
[0051] (2) Dissolve 292.7 mg of manganese bromide tetrahydrate in 490 μl of 4 M manganese nitrate solution by ultrasonication; dissolve 18.5 mg of tungsten trioxide in 300 μl of anhydrous ethanol by ultrasonication; mix the above solutions and mechanically shake to obtain a precursor solution;
[0052] (3) Preheat the heating plate to 250°C; Place the pretreated conductive carbon cloth flat on the heating plate and add 50 μL of the above precursor solution drop by drop, ensuring that the precursor solution is evenly loaded on the conductive carbon cloth; After the addition is completed, maintain the temperature at 250°C for 3 hours;
[0053] (4) calcining under vacuum at 400°C for 3 hours; after cooling to room temperature, ultrasonicating in deionized water for 30 seconds and rinsing three times; drying in an oven at 60°C to obtain a manganese-based oxybromide-tungsten oxide composite material supported on a conductive carbon cloth.
[0054] Example 3:
[0055] (1) 2*1cm 2 The conductive carbon cloth was sequentially immersed in acetone, anhydrous ethanol, and deionized water for 5 minutes and then dried; then placed in a 40% nitric acid solution and treated under ultrasonic conditions for 40 minutes;
[0056] (2) Dissolve 292.7 mg of manganese bromide tetrahydrate in 490 μl of 4 M manganese nitrate solution by ultrasonication; dissolve 18.5 mg of tungsten trioxide in 300 μl of anhydrous ethanol by ultrasonication; mix the above solutions and mechanically shake to obtain a precursor solution;
[0057] (3) Preheat the heating plate to 300°C; Place the pretreated conductive carbon cloth flat on the heating plate and add 100 μL of the above precursor solution drop by drop, ensuring that the precursor solution is evenly loaded on the conductive carbon cloth; After the addition is completed, maintain 300°C for 3 hours;
[0058] (4) calcining under vacuum at 400°C for 3 hours; after cooling to room temperature, ultrasonicating in deionized water for 30 seconds and rinsing three times; drying in an oven at 60°C to obtain a manganese-based oxybromide-tungsten oxide composite material supported on a conductive carbon cloth.
[0059] Example 4:
[0060] (1) 2*1cm 2 The conductive carbon cloth was sequentially immersed in acetone, anhydrous ethanol, and deionized water for 5 minutes and then dried; then placed in a 40% nitric acid solution and treated under ultrasonic conditions for 40 minutes;
[0061] (2) Dissolve 292.7 mg of manganese bromide tetrahydrate in 490 μl of 4 M manganese nitrate solution by ultrasonication; dissolve 18.5 mg of tungsten trioxide in 300 μl of anhydrous ethanol by ultrasonication; mix the above solutions and mechanically shake to obtain a precursor solution;
[0062] (3) Preheat the heating plate to 250°C; Place the pretreated conductive carbon cloth flat on the heating plate and add 300 μL of the above precursor solution drop by drop, ensuring that the precursor solution is evenly loaded on the conductive carbon cloth; After the addition is completed, maintain the temperature at 250°C for 2 hours;
[0063] (4) calcining under vacuum at 400°C for 3 hours; after cooling to room temperature, ultrasonicating in deionized water for 30 seconds and rinsing three times; drying in an oven at 60°C to obtain a manganese-based oxybromide-tungsten oxide composite material supported on a conductive carbon cloth.
[0064] Example 5:
[0065] (1) 2*1cm 2 The conductive carbon cloth was sequentially immersed in acetone, anhydrous ethanol, and deionized water for 5 minutes and then dried; then placed in a 40% nitric acid solution and treated under ultrasonic conditions for 40 minutes;
[0066] (2) Dissolve 292.7 mg of manganese bromide tetrahydrate in 490 μl of 4 M manganese nitrate solution by ultrasonication; dissolve 18.5 mg of tungsten trioxide in 300 μl of anhydrous ethanol by ultrasonication; mix the above solutions and mechanically shake to obtain a precursor solution;
[0067] (3) Preheat the heating plate to 250°C; Place the pretreated conductive carbon cloth flat on the heating plate and add 350 μL of the above precursor solution drop by drop, ensuring that the precursor solution is evenly loaded on the conductive carbon cloth; After the addition is completed, maintain the temperature at 250°C for 5 hours;
[0068] (4) calcining under vacuum at 400°C for 3 hours; after cooling to room temperature, ultrasonicating in deionized water for 30 seconds and rinsing three times; drying in an oven at 60°C to obtain a manganese-based oxybromide-tungsten oxide composite material supported on a conductive carbon cloth.
[0069] Example 6:
[0070] (1) 2*1cm 2 The conductive carbon cloth was sequentially immersed in acetone, anhydrous ethanol, and deionized water for 5 minutes and then dried; then placed in a 40% nitric acid solution and treated under ultrasonic conditions for 40 minutes;
[0071] (2) Dissolve 292.7 mg of manganese bromide tetrahydrate in 490 μl of 4 M manganese nitrate solution by ultrasonication; dissolve 18.5 mg of tungsten trioxide in 300 μl of anhydrous ethanol by ultrasonication; mix the above solutions and mechanically shake to obtain a precursor solution;
[0072] (3) Preheat the heating plate to 300°C; Place the pretreated conductive carbon cloth flat on the heating plate and add 350 μL of the above precursor solution drop by drop, ensuring that the precursor solution is evenly loaded on the conductive carbon cloth; After the addition is completed, maintain the temperature at 300°C for 3 hours;
[0073] (4) calcining under vacuum at 500°C for 3 hours; after cooling to room temperature, ultrasonicating in deionized water for 30 seconds and rinsing three times; drying in an oven at 60°C to obtain a manganese-based oxybromide-tungsten oxide composite material supported on a conductive carbon cloth.
[0074] Example 7:
[0075] (1) 2*1cm 2 The conductive carbon cloth was sequentially immersed in acetone, anhydrous ethanol, and deionized water for 10 minutes and then dried; then placed in a 40% nitric acid solution and treated under ultrasonic conditions for 40 minutes;
[0076] (2) Dissolve 292.7 mg of manganese bromide tetrahydrate in 490 μl of 4 M manganese nitrate solution by ultrasonication; dissolve 18.5 mg of tungsten trioxide in 300 μl of anhydrous ethanol by ultrasonication; mix the above solutions and mechanically shake to obtain a precursor solution;
[0077] (3) Preheat the heating plate to 160°C; Place the pretreated conductive carbon cloth flat on the heating plate and add 350 μL of the above precursor solution dropwise, ensuring that the precursor solution is evenly loaded on the conductive carbon cloth; After the addition is completed, maintain the temperature at 160°C for 3 hours;
[0078] (4) calcining under vacuum at 400°C for 3 hours; after cooling to room temperature, ultrasonicating in deionized water for 30 seconds and rinsing three times; drying in an oven at 60°C to obtain a manganese-based oxybromide-tungsten oxide composite material supported on a conductive carbon cloth.
[0079] Example 8:
[0080] (1) 2*1cm 2 The conductive carbon cloth was sequentially immersed in acetone, anhydrous ethanol, and deionized water for 5 minutes and then dried; then placed in a 40% nitric acid solution and treated under ultrasonic conditions for 40 minutes;
[0081] (2) Dissolve 292.7 mg of manganese bromide tetrahydrate in 490 μl of 4 M manganese nitrate solution by ultrasonication; dissolve 18.5 mg of tungsten trioxide in 300 μl of anhydrous ethanol by ultrasonication; mix the above solutions and mechanically shake to obtain a precursor solution;
[0082] (3) Preheat the heating plate to 220°C; Place the pretreated conductive carbon cloth flat on the heating plate and add 200 μL of the above precursor solution drop by drop, ensuring that the precursor solution is evenly loaded on the conductive carbon cloth; After the addition is completed, maintain the temperature at 220°C for 3 hours;
[0083] (4) Vacuum calcination at 400°C for 4 hours; after cooling to room temperature, ultrasonication in deionized water for 30 seconds and rinsing three times; drying in an oven at 60°C to obtain a manganese-based oxybromide-tungsten oxide composite material supported on a conductive carbon cloth.
[0084] Example 9:
[0085] (1) 2*1cm 2 The conductive carbon cloth was sequentially immersed in acetone, anhydrous ethanol, and deionized water for 5 minutes and then dried; then placed in a 40% nitric acid solution and treated under ultrasonic conditions for 40 minutes;
[0086] (2) Dissolve 292.7 mg of manganese bromide tetrahydrate in 490 μl of 4 M manganese nitrate solution by ultrasonication; dissolve 18.5 mg of tungsten trioxide in 300 μl of anhydrous ethanol by ultrasonication; mix the above solutions and mechanically shake to obtain a precursor solution;
[0087] (3) Preheat the heating plate to 220°C; Place the pretreated conductive carbon cloth flat on the heating plate and add 200 μL of the above precursor solution drop by drop, ensuring that the precursor solution is evenly loaded on the conductive carbon cloth; After the addition is completed, maintain the temperature at 220°C for 3 hours;
[0088] (4) Vacuum calcination at 500°C for 4 hours; after cooling to room temperature, ultrasonication in deionized water for 30 seconds and rinsing three times; drying in an oven at 60°C to obtain a manganese-based oxybromide-tungsten oxide composite material supported on a conductive carbon cloth.
[0089] Comparative Example 1:
[0090] (1) 2*1cm 2 The conductive carbon cloth was sequentially immersed in acetone, anhydrous ethanol, and deionized water for 5 minutes and then dried; then placed in a 40% nitric acid solution and treated under ultrasonic conditions for 40 minutes;
[0091] (2) 292.7 mg of manganese bromide tetrahydrate was dissolved in 300 μL of anhydrous ethanol by ultrasonication, mixed with 500 μL of 4 M manganese nitrate solution, and mixed by mechanical shaking to obtain a precursor solution;
[0092] (3) Preheat the heating plate to 220°C; Place the pretreated conductive carbon cloth flat on the heating plate and add 200 μL of the above precursor solution drop by drop, ensuring that the precursor solution is evenly loaded on the conductive carbon cloth; After the addition is completed, maintain the temperature at 220°C for 3 hours;
[0093] (4) Vacuum calcination at 400°C for 3 hours; after cooling to room temperature, ultrasonication in deionized water for 30 seconds and rinsing three times; drying in an oven at 60°C to obtain a manganese-based bromide oxide material supported on a conductive carbon cloth.
[0094] Comparative Example 2:
[0095] (1) 2*1cm 2 The conductive carbon cloth was sequentially immersed in acetone, anhydrous ethanol, and deionized water for 5 minutes and then dried; then placed in a 40% nitric acid solution and treated under ultrasonic conditions for 40 minutes;
[0096] (2) 18.5 mg of tungsten trioxide was dissolved in 500 μL of 4 M manganese nitrate solution by ultrasonication and mechanical shaking to ensure that the two were fully mixed to obtain a precursor solution;
[0097] (3) Preheat the heating plate to 220°C; Place the pretreated conductive carbon cloth flat on the heating plate and add 200 μL of the above precursor solution drop by drop, ensuring that the precursor solution is evenly loaded on the conductive carbon cloth; After the addition is completed, maintain the temperature at 220°C for 3 hours;
[0098] (4) Vacuum calcination at 400°C for 3 hours; after cooling to room temperature, ultrasonication in deionized water for 30 seconds and rinsing three times; drying in an oven at 60°C to obtain a manganese-based tungsten oxide material supported on a conductive carbon cloth.
[0099] In the manganese-based tungsten oxide-carbon-based composite material prepared in this comparative example, the chemical composition of the manganese-based tungsten oxide is MnO2@WO3.
[0100] Performance testing:
[0101] (1) Morphological characterization:
[0102] Example 1:
[0103] The composite material prepared in Example 1 of the present invention was tested by XRD ( Figure 3 ), which is a polycrystalline structure. By comparing the PDF cards, we know that the composite material has both Mn 7.5 O 10 The characteristic peaks of Br3's lattice diffraction also have the characteristic peaks of WO3's lattice diffraction, which confirms that its chemical composition is Mn 7.5 O 10 Br3-WO3.
[0104] The TEM and HRTEM of the composite material prepared in Example 1 of the present invention are respectively Figure 4 、 5 -6. Among them, Figure 5 The corresponding Mn of the composite material is shown 7.5 O 10 The 303 characteristic lattice of Br3 and the 120, 122 characteristic lattices of WO3. Figure 6 The corresponding Mn of the composite material is shown 7.5 O 10 The 220 characteristic lattice of Br3.
[0105] Through the above characterization ( Figure 3 and Figure 5 ) It can be seen that the present invention successfully prepared the Mn-based 7.5 O 10 Manganese-based oxybromide-tungsten oxide composite materials of Br3-WO3.
[0106] Comparative Example 1:
[0107] The manganese-based oxybromide material prepared in this comparative example was tested by XRD ( Figure 3 ), which has a polycrystalline structure. By comparing the PDF card, we know that its chemical composition is Mn 7.5 O 10 Br3.
[0108] (2) Electrochemical performance test
[0109] (1) The carbon-based composite materials prepared in the above examples and comparative examples were cut into pieces with a size of 1*1.5 cm and evenly coated with waterproof silicone. During this process, the area for clamping the electrodes and the specific part in contact with water should be reserved. The silicone was allowed to dry naturally overnight to solidify.
[0110] (2) An Ag / AgCl electrode was used as the reference electrode, a graphite electrode was used as the counter electrode, and a platinum electrode holder was used as the working electrode;
[0111] (3) Linear sweep voltammetry (LSV) was performed in a saturated 0.5 M H2SO4 solution at a scan rate of 1 mV / s to obtain polarization curves.
[0112] The polarization curves of Example 1 and Comparative Examples 1-2 are shown in FIG. Figure 1 , the potential reference of the present invention uses reversible hydrogen electrode (RHE): E RHE =E Ag / AgCl +0.197+0.059×pH (0.5M H2SO4 solution); according to the formula η=E RHE The overpotential (η) was calculated from -1.23 V. The calculated overpotential for Example 1 under acidic conditions was 236 mV. The oxygen evolution catalytic performance of Comparative Example 1 under acidic conditions increased by approximately 43 mV compared to that of Example 1. The oxygen evolution catalytic performance of Comparative Example 2 under acidic conditions increased by approximately 112 mV compared to that of Example 1.
[0113] In addition, the catalyst material obtained in Example 1 was continuously applied with 200 mA cm -2 At a constant current density of , the working voltage and time relationship curve relative to the reversible hydrogen electrode was obtained by electrochemical workstation test. Figure 2 , which can stably catalyze the water-to-oxygen reaction for 1650 hours, with an overpotential rise rate of 0.057 mV / h. Therefore, the composite material prepared by the present invention exhibits excellent stability in the electrocatalytic water-to-oxygen reaction in an acidic environment.
[0114] During the above test process, all electrode potential data were 100% compensated for voltage drop.
[0115] In summary, the manganese-based oxybromide-tungsten oxide composite material provided by the present invention is suitable for electrochemical oxygen evolution reaction under acidic conditions. Compared with manganese-based oxide electrocatalysts, the manganese-based oxybromide-tungsten oxide composite material exhibits higher activity and good stability.
[0116] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.
Claims
1. A method for preparing a manganese-based oxybromide-tungsten oxide composite material, characterized in that: The following steps are involved: (1) preparing a precursor solution containing manganese-based halide, manganese-based inorganic salt and tungsten trioxide; (2) immersing a conductive substrate in the precursor solution or applying a drop of the precursor solution on a conductive substrate to obtain a conductive substrate adsorbing the precursor solution; (3) heating the conductive substrate adsorbing the precursor solution at 160° C. to 300° C.; (4) The conductive substrate after heat treatment is vacuum-fired.
2. The preparation method according to claim 1, characterized in that In step (1), the manganese-based halide is manganese bromide tetrahydrate or manganese bromide; And / or, in step (1), the manganese-based inorganic salt is manganese nitrate tetrahydrate or manganese nitrate; And / or, in step (1), the solvent of the precursor solution is a mixed solvent of water and an organic solvent; the organic solvent is selected from at least one of ethanol, isopropanol, dimethylformamide, ethyl acetate, and acetone; And / or, in step (1), the precursor solution further contains a doping element; the doping element is selected from at least one of ruthenium, iridium, cobalt, nickel, chromium, iron, molybdenum, bismuth, tantalum, silver, rhodium, strontium, aluminum and titanium.
3. The preparation method according to claim 1, characterized in that In step (1), the molar ratio of manganese in the manganese-based halide to manganese in the manganese-based inorganic salt is 1:1 to 5; And / or, in step (1), the molar ratio of manganese in the manganese-based halide and the manganese-based inorganic salt to tungsten in tungsten trioxide is 10 to 50:
1.
4. The preparation method according to claim 1, characterized in that In step (2), the conductive substrate is pretreated by acidification; the acidification is to ultrasonically treat the conductive substrate in an acid solution; the acid solution is a nitric acid solution or a hydrochloric acid solution; and the ultrasonic treatment time is 30 to 40 minutes.
5. The preparation method according to claim 1, characterized in that In step (2), the adsorption amount per unit area of manganese on the conductive substrate is 0.00009 to 0.0007 mol / cm 2 .
6. The preparation method according to claim 1, characterized in that In step (3), the heating treatment time is 2 to 5 hours; And / or, in step (4), the vacuum burning temperature is 200-800°C; And / or, in step (4), the vacuum burning time is 2 to 4 hours.
7. The manganese-based oxybromide-tungsten oxide composite material obtained by the preparation method according to any one of claims 1 to 6.
8. Use of the manganese-based oxybromide-tungsten oxide composite material according to claim 7 in the preparation of electrochemical catalysts.
9. The use according to claim 8, characterized in that Application in the preparation of oxygen evolution reaction catalysts.
10. The use according to claim 9, characterized in that Application in the preparation of acidic electrolyte oxygen evolution reaction catalyst.