A method for preparing a 3D-printed CuFe2O4 electrode
Potassium salt-induced CuFe2O4[111] powder catalyst was prepared by solution combustion and combined with 3D printing technology, which solved the problem of insufficient proton adsorption and desorption sites in the catalyst and achieved efficient hydrogen evolution in alkaline medium.
Patent Information
- Application Number
- CN202310828638.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-07-07
- Publication Date
- 2026-08-25
- Estimated Expiration
- 2043-07-07
AI Technical Summary
In alkaline media, existing catalysts have insufficient proton adsorption and desorption sites, which leads to the catalytic active sites being occupied by gas, inhibiting catalytic efficiency and making it difficult to achieve high-performance hydrogen evolution under extremely low bias voltage.
Potassium salt-induced CuFe2O4[111] powder catalyst was prepared by solution combustion method, and combined with 3D printing technology to regulate the spatial distribution of active sites, thus preparing CuFe2O4 electrode with excellent water dissociation performance.
This significantly improved the hydrogen evolution performance of the catalyst under alkaline conditions, achieving highly efficient hydrogen evolution through water electrolysis under extremely low applied bias voltage.
Smart Images
Figure CN116676616B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electrocatalysts and electrode preparation, specifically, a method for preparing a 3D-printed CuFe2O4 electrode for use in alkaline water electrolysis for hydrogen evolution under extremely low bias voltage. Background Technology
[0002] Hydrogen is considered the best alternative to fossil fuels due to its high energy density and cleanliness, and the hydrogen evolution reaction (HER) is a highly attractive method for large-scale hydrogen production. In alkaline media, the number of protons present is limited, and the HER process inevitably involves a water splitting step to generate protons that adsorb onto catalytic sites, followed by hydrogen adsorption and desorption. Therefore, improving the water dissociation capacity of the HER catalyst can significantly enhance its alkaline HER performance. On the other hand, too few proton adsorption and desorption sites can lead to the catalytic active sites being occupied by the evolved gas, inhibiting proton adsorption performance and thus reducing overall catalytic efficiency. Constructing catalysts with spatially distributed active sites will effectively increase the number of proton adsorption and desorption sites, further improving HER performance.
[0003] This invention proposes a method for preparing CuFe2O4 electrodes using 3D printing. By introducing a potassium salt solid solvent as a crystal facet control strategy during the preparation process, the crystal facets of the CuFe2O4 powder catalyst are reconstructed. This unique crystal facet arrangement exhibits excellent water dissociation performance. Furthermore, by controlling the type of binder and the ratio of the printing slurry, the powder catalyst is printed into electrodes, significantly increasing the spatial distribution of active sites and achieving high-performance hydrogen evolution under alkaline conditions. Summary of the Invention
[0004] This invention provides a method for preparing a 3D-printed CuFe2O4 electrode. The preparation process consists of two steps: preparing a CuFe2O4
[111] powder catalyst with potassium salt-induced crystal orientation change by solution combustion and preparing a 3D-printed electrode. The advantage of this method is that the prepared electrode has excellent water electrolysis hydrogen evolution performance and spatial active site distribution, which can achieve efficient alkaline hydrogen evolution under extremely low applied bias voltage. This method is implemented by the following technical solution:
[0005] Step 1: Dissolve oxidant a, oxidant b, fuel, and potassium salt in water to obtain a solution combustion precursor solution;
[0006] Step 2: The precursor solution of the solution combustion method is transferred to a muffle furnace for combustion. After being kept at a certain temperature for a period of time, it is taken out, cooled, ground, washed, and dried to obtain the catalyst powder material, which is CuFe2O4
[111] powder catalyst.
[0007] Step 3: Dissolve the binder in water to obtain a binder solution. Add the catalyst powder to the binder solution and stir thoroughly to obtain the 3D printing electrode slurry.
[0008] Step 4: Pour the slurry containing catalyst powder into the dispensing syringe, start the air compressor, control the outlet pressure of the dispensing machine, fix the syringe on the three-dimensional motion platform, and print the slurry according to the set printing path to obtain the printed pre-treated electrode.
[0009] Step 5: Heat-treat the pre-printed electrode to remove residual binder and sinter the catalyst powder to obtain a 3D-printed CuFe2O4
[111] electrode;
[0010] Step 6: Using the prepared catalyst electrode as the cathode, a platinum sheet as the counter electrode, a mercury / mercury oxide electrode as the reference electrode, and KOH solution as the electrolyte, perform the electrocatalytic hydrogen evolution reaction.
[0011] Further, in step 1 above, the oxidant a comprises one or more copper salt compounds selected from CuCl2, CuCl, CuSO4, Cu2SO4, Cu(NO3)2, and CuNO3; the oxidant b comprises one or more iron salt compounds selected from FeCl3, FeCl2, Fe2(SO4)3, FeSO4, Fe(NO3)3, and Fe(NO3)2; the fuel comprises one or more compounds selected from monosodium glutamate, hydroxyacetamide, glycine, hydrazine formate, ammonium nitrate, and glucose; and the potassium salt comprises one or more potassium salt compounds selected from KCl, K3PO4, K2SO4, and KNO3.
[0012] Furthermore, in step 1 above, the molar ratio of oxidant a to oxidant b is 1:5 to 5:1;
[0013] Furthermore, in step 1 above, the molar ratio of fuel to oxidant a is 1:5 to 5:1;
[0014] Furthermore, in step 1 above, the molar ratio of the potassium salt to oxidant a is 1:5 to 5:1;
[0015] Furthermore, in step 2 above, the combustion temperature is 350–450°C, and the holding time is 3–10 min;
[0016] Furthermore, in step 3 above, the adhesive comprises one or more compounds selected from polyvinyl butyral, polyvinyl alcohol, polyvinylpyrrolidone, and hexadecyltrimethylammonium bromide.
[0017] Furthermore, in step 3 above, the mass ratio of the adhesive to water in the adhesive solution is 5:95 to 95:5;
[0018] Furthermore, in step 3 above, the mass ratio of the binder solution to the powder catalyst is 5:30 to 30:5;
[0019] Furthermore, in step 4 above, the outlet pressure of the dispensing machine is 0.1–1.0 MPa;
[0020] Furthermore, in step 5 above, the heat treatment atmosphere is one or more gases selected from oxygen, argon, nitrogen, and carbon dioxide; the heat treatment temperature is 100–1000°C, and the holding time is 30–180 min. Attached Figure Description
[0021] Figure 1 This is the XRD (X-ray diffraction) pattern of the electrode.
[0022] Figure 2 It is the LSV (linear sweep voltammetry) curve of the electrode.
[0023] Figure 3 The electrodes are respectively at 10 mA / cm 2 (Horizontal axis) and 20mA / cm 2 (Vertical axis) Schematic diagram of the required overpotential corresponding to the current density.
[0024] Figure 4 These are optical photographs of the front and back sides of the 3D printed electrode (a). Detailed Implementation
[0025] Example 1
[0026] 1. Preparation of CuFe2O4
[111] powder catalyst and carbon paper drop-coated electrode by solution combustion method:
[0027] (1) Add 115.6 mg Cu(NO3)2, 96.8 mg Fe(NO3)3·9H2O4, 94.7 mg KNO3, and 307.7 mg glycine to a 250 ml beaker, add 3 ml of deionized water and dissolve them, and sonicate to mix them well as a precursor solution for the solution combustion method.
[0028] (2) The beaker containing the precursor solution was placed in a muffle furnace at 400°C and burned in air atmosphere for 5 minutes to obtain a loose and porous black solid. This solid was then ground, washed three times with deionized water, and dried to obtain CuFe2O4
[111] powder catalyst. (See attached...) Figure 1As shown, the dominant crystal plane of the CuFe2O4 powder catalyst without the addition of potassium salt is
[311] . When potassium salt is added, the
[311] crystal plane of the CuFe2O4
[111] powder catalyst disappears and a new dominant crystal plane
[111] appears, indicating that potassium salt induces a change in the crystal orientation of CuFe2O4.
[0029] (3) Weigh 50 mg of CuFe2O4
[111] powder catalyst and place it in a mixture of 100 μL of 1% perfluorosulfonic acid solution and 1900 μL of anhydrous ethanol. Mix the mixture by ultrasonication for 30 min to obtain the electrode coating solution. Take 30 μL of the electrode coating solution and drop it evenly onto a 1×2 cm... 2 On a piece of carbon paper of size 1×1cm, a drop coating area of 1×1cm is applied. 2 The carbon paper after drop coating was placed in a 50°C oven and dried for 10 min to obtain a CuFe2O4
[111] drop-coated electrode. When the powder catalyst used is CuFe2O4, the electrode obtained is a CuFe2O4 drop-coated electrode.
[0030] 2. Fabrication of 3D-printed electrodes:
[0031] (1) Weigh 5g of polyvinyl alcohol powder and add it to 45g of water. Heat to 75℃ and stir until the polyvinyl alcohol is completely dissolved to obtain a polyvinyl alcohol solution. Place 5g of polyvinyl alcohol solution in a beaker, add 18.75g of CuFe2O4
[111] powder catalyst, stir evenly and then add it to the dispensing syringe to complete the preparation of printing paste.
[0032] (2) Assemble the dispensing needle onto the dispensing syringe, and connect the other end of the syringe to the dispensing machine. Start the air compressor to provide high-pressure airflow as the power for printing the paste. Connect the air compressor outlet to the dispensing machine and control the outlet pressure at 0.7MPa. Print the paste according to the set printing path to obtain the pre-treated electrode.
[0033] (3) The pre-treated printed electrode is placed in a tube furnace, argon protective gas is introduced, the furnace temperature is raised to 900℃, and then kept at that temperature for 120 min. After cooling, it is taken out to obtain CuFe2O4
[111] 3D printed electrode. When the powder catalyst used is CuFe2O4, the printed electrode is CuFe2O4 3D printed electrode.
[0034] 3. HER performance testing of electrodes:
[0035] A 1 mol / L KOH solution was prepared as the electrolyte. The prepared electrode was fixed with an electrode clamp and used as the working electrode. A platinum sheet was used as the counter electrode, and mercury / mercury oxide was used as the reference electrode. LSV scanning was performed on the prepared electrode. (See attached diagram) Figure 2As shown, compared with the CuFe2O4 drop-coated electrode, the hydrogen evolution performance of the CuFe2O4
[111] drop-coated electrode is significantly improved. The CuFe2O4
[111] 3D printed electrode further printed exhibits better hydrogen evolution performance than the CuFe2O4
[111] drop-coated electrode. (See attached image) Figure 3 As shown, the CuFe2O4 drop-coated electrode reaches 10 mA / cm². 2 At a current density of 161mV, an overpotential of 161mV is required; to reach 20mA / cm 2 At a current density of 10 mA / cm², the required overpotential is 274 mV. The CuFe₂O₄
[111] drop-coated electrode reaches 10 mA / cm². 2 At a current density of 10⁵ mV, an overpotential of 10⁵ mV is required; to reach 20 mA / cm², the overpotential is 10⁵ mV. 2 At a current density of 10 mA / cm², an overpotential of 174 mV is required. The CuFe₂O₄ 3D printed electrode achieves this overpotential at 10 mA / cm². 2 At a current density of 20 mA / cm², an overpotential of 90 mV is required; to reach 20 mA / cm², an overpotential of 90 mV is required. 2 At a current density of 10 mA / cm², the required overpotential is 136 mV. The CuFe₂O₄
[111] 3D printed electrode reaches 10 mA / cm². 2 At current densities of 20 mA / cm², only 39 mV of overpotential is required; at 20 mA / cm², the required overpotential is 39 mV. 2 At the required current density, only 56 mV of overpotential is needed. Experimental data show that using potassium salt to control crystal orientation and 3D printing to fabricate electrodes can achieve high-performance hydrogen evolution under extremely low applied bias voltage in alkaline conditions.
Claims
1. A method for preparing a 3D-printed CuFe2O4 electrode, characterized in that, First, a powder catalyst CuFe2O4 with potassium nitrate-induced altered crystal orientation was prepared by solution combustion [111]. Then, the powder catalyst was printed into an electrode by 3D printing technology to obtain the CuFe2O4 [111] printed electrode, which was then used for electrocatalytic hydrogen evolution reaction. The precursor solution of solution combustion method contains oxidant a, oxidant b, fuel, and potassium nitrate. Oxidant a contains one or two of Cu(NO3)2 and CuNO3. Oxidant b contains one or two of Fe(NO3)3 and Fe(NO3)2. The molar ratio of oxidant a to oxidant b is 5:1 to 1:
5. The fuel contains one or more compounds of hydroxyacetamide, glycine, hydrazine formate, ammonium nitrate, and glucose. The molar ratio of fuel to oxidant a is 5:1 to 1:
5. The molar ratio of potassium nitrate to oxidant a is 5:1 to 1:
5.
2. The method for preparing a 3D-printed CuFe2O4 electrode according to claim 1, characterized in that, The ignition temperature for the solution combustion method is 350–450℃, and the holding time is 3–10 min.
3. The method for preparing a 3D-printed CuFe2O4 electrode according to claim 1, characterized in that, The binder in the 3D printing process contains one or more compounds selected from polyvinyl butyral, polyvinyl alcohol, polyvinylpyrrolidone, and hexadecyltrimethylammonium bromide; the mass ratio of binder to water is 5:95 to 95:5, and the mass ratio of binder solution to powder catalyst is 5:30 to 30:
5.
4. A method for preparing a 3D-printed CuFe2O4 electrode according to claim 1, characterized in that, The outlet pressure of the dispensing machine during the 3D printing process is 0.1 to 1.0 MPa.
5. A method for preparing a 3D-printed CuFe2O4 electrode according to claim 1, characterized in that, The heat treatment atmosphere in the 3D printing process is one or more gases selected from oxygen, argon, nitrogen, and carbon dioxide. The heat treatment temperature is 100–1000℃, and the holding time is 30–180 min.
6. The application of a 3D-printed CuFe2O4 electrode according to claim 1, characterized in that, The prepared CuFe2O4[111] printed electrode was used for electrocatalytic hydrogen evolution reaction under alkaline conditions, and showed high efficiency hydrogen evolution activity under extremely low applied bias voltage.