A three-phase composite material of perovskite, carbon, and alloy particles, its preparation method, and its application in water electrolysis.
By in-situ precipitation of metal/alloy particles on perovskite particles and coating them with a carbon-nitrogen shell, a three-phase composite material is formed, which solves the problems of low catalytic current density, high overpotential and poor stability of existing OER electrocatalysts, and realizes a highly efficient and low-cost catalytic electrolysis of water anode reaction.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- DALIAN INSTITUTE OF CHEMICAL PHYSICS CHINESE ACADEMY OF SCIENCES
- Filing Date
- 2021-12-09
- Publication Date
- 2026-05-26
AI Technical Summary
Existing OER electrocatalysts suffer from problems such as low catalytic current density, high overpotential, poor stability, and complex synthesis methods. In particular, perovskite materials have poor conductivity at room temperature, which limits their oxygen catalytic activity.
By in-situ precipitation of metal/alloy particles on perovskite particles and coating their surface with a carbon-nitrogen shell, a three-phase composite material of perovskite, carbon, and alloy particles is formed. A polydopamine coating is formed by the self-polymerization of dopamine salt in an alkaline solution, followed by carbonization to form a uniform carbon-nitrogen shell, thereby improving conductivity and catalytic activity.
It significantly improves the catalytic activity and stability of the catalyst, reduces the overpotential, simplifies the synthesis process, and is low in cost and easy to operate.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of electrochemical catalysts, specifically relating to a three-phase composite material of perovskite, carbon, and alloy particles, its preparation method, and its application in water electrolysis. Background Technology
[0002] With the global fossil fuel crisis and the continuous increase in pollutants and greenhouse gas levels, there is an urgent need to develop clean and sustainable energy resources in the coming decades to gradually reduce the use of fossil fuels. Hydrogen energy, with its high calorific value and water as a combustion product, is a green and clean secondary energy source. It can utilize renewable energy sources such as solar and wind power to generate electricity, which can then be used to produce hydrogen through water electrolysis. This converts energy into chemical energy for storage, while the energy produced by hydrogen combustion can be used for human society. The reaction produces only water, making it a zero-carbon emission process. Large-scale utilization can truly achieve "zero" carbon emissions and "zero" pollution. Therefore, vigorously developing water electrolysis technology is necessary. Water splitting consists of two half-reactions: the hydrogen evolution reaction (HER) at the cathode, where H2O gains electrons to generate hydrogen, and the oxygen evolution reaction (OER) at the anode, where OH- loses electrons to generate O2. However, both OER and HER require an overpotential to proceed, and because OER is a complex four-electron transfer process, its kinetics are slow. Its overpotential is greater than that of HER, which is the main factor affecting the water splitting rate. This significantly hinders the development of hydrogen production through water electrolysis. Currently, due to the energy consumption and low economic efficiency of water electrolysis, hydrogen production from water electrolysis accounts for only 4% of global hydrogen production. Therefore, it is necessary to reduce the overpotential and accelerate the oxygen evolution reaction (OER). OER catalysts are mainly classified into noble metal materials, transition metal oxide materials, and carbon materials. Among them, perovskite materials have attracted much attention due to their low cost, ease of large-scale manufacturing, flexible structure, and variable composition.
[0003] In recent years, composite materials combining functional catalyst nanoparticles with perovskite oxide supports have attracted increasing attention. Exsolution based on in-situ growth of metal nanoparticles from perovskite parent materials is an attractive method for designing nanoparticles loaded onto perovskite materials. Ohhun Kwon et al. reported on this in *Nature Communications*, Volume 8, 2018, page 15967, regarding the application of functional catalyst nanoparticles to perovskite materials. 1.7 T 0.3 O 5+δ Uniformly dispersed metal nanoparticles were grown in situ on layered perovskites (T = Mn, Co, Ni, and Fe), and it was demonstrated that the exsoluted metal particles contribute to improved electrochemical performance.
[0004] Electrocatalysis requires efficient electron flow through the electrode to generate high current; therefore, the conductivity of the electrocatalyst is crucial for efficient catalysis. However, most perovskite oxides exhibit poor conductivity at room temperature, limiting their oxygen evolution reaction (OER) catalytic activity. To address this issue, highly conductive carbon second phases (including carbon black, carbon nanotubes, and graphene) are added to improve the conductivity of the perovskite. Furthermore, forming a continuous interface between the perovskite and carbon phases facilitates more efficient electron transfer within the composite electrode. Coating the material surface with a uniform carbon layer contributes to improved electrocatalytic activity. Shaohong Liu et al. reported a method for forming a carbon-nitrogen shell on a ZIF surface in *Advanced Materials*, 2017, Vol. 29, p. 1700874. The heterohybridization between the two phases resulted in excellent OER catalytic performance and durability. Summary of the Invention
[0005] The purpose of this invention is to address the problems of existing OER electrocatalysts, such as low cost, low catalytic current density, high overpotential, poor stability, and complex synthesis methods. This invention provides a simple and rapid method for synthesizing perovskite, carbon, and alloy particle composite materials, which can be used for the anodic reaction of catalytic water electrolysis.
[0006] One of the objectives of this invention is to provide a three-phase composite material of perovskite, carbon, and alloy particles, wherein perovskite particles precipitate metal / alloy particles in situ, and a carbon-nitrogen shell is coated on the perovskite and precipitated metal / alloy particles.
[0007] Furthermore, in the above technical solution, the perovskite size is 100-200 nm; the thickness of the carbon-nitrogen shell is 10±2 nm, and the thickness is adjustable.
[0008] A second objective of this invention is to provide a method for preparing a three-phase composite material of perovskite, carbon, and alloy particles, the method comprising the following steps:
[0009] (1) Prepare a Tris alkaline solution by adding the perovskite material to the Tris alkaline solution and dispersing it under ultrasonic probe to obtain a dispersion.
[0010] (2) Add dopamine salt to the dispersion obtained in step (1) and ultrasonically disperse for 5 min. Then place it on a stirrer and stir for 6-24 h, preferably 6 h, 12 h or 24 h. Centrifuge and freeze dry.
[0011] (3) The product obtained in step (2) is roasted in a roasting atmosphere to obtain the perovskite, carbon and alloy particle three-phase composite material.
[0012] Furthermore, in the above technical solution, the perovskite material is a perovskite structure oxide with the chemical formula ABO3; wherein, the metal at the A site is an alkaline earth metal, the metal at the B site is a transition metal, and the A and B sites can be a single metal or a complex combination of several metals; the number of complex combinations of metals is two to three, and the total number of metal elements in the perovskite material is two to four.
[0013] Furthermore, in the above technical solutions, the perovskite composition is different, and the size composition of the precipitated alloy / metal particles is also different. The alkaline earth metals include beryllium, magnesium, calcium, strontium, and barium; transition metals include titanium, vanadium, chromium, iron, cobalt, nickel, copper, zinc, zirconium, niobium, and molybdenum.
[0014] Furthermore, in the above technical solution, different mass ratios of the perovskite material and dopamine salt will adjust the final carbon-nitrogen shell thickness; the mass ratio of perovskite to dopamine salt varies between 20 and 4.
[0015] Furthermore, in the above technical solution, the diameter of the perovskite material is 100-200 nm; the perovskite material can be uniformly dispersed in water and can maintain stability in water.
[0016] Furthermore, in the above technical solution, the alloy particles are precipitated in situ during the carbonization process of the polydopamine coating, and the carbon-nitrogen shell has good encapsulation properties for the alloy / metal particles and perovskite.
[0017] Furthermore, in the above technical solution, the pH of the Tris alkaline solution is 8-9, preferably 8.5, the calcination temperature is 700-800℃, preferably 700℃, and the time is 3-4h, preferably 3h.
[0018] Furthermore, in the above technical solution, during the polymerization of the dopamine salt in an alkaline solution, the polymerization time can be adjusted to control the thickness of the dopamine coating, thereby regulating the thickness of the carbon-nitrogen shell after carbonization. The polymerization time is proportional to the thickness of the dopamine coating, with a polymerization time of 3-24 hours and a corresponding coating thickness of 5-50 nm.
[0019] Furthermore, in the above technical solutions, the dispersion methods include stirring and ultrasonication.
[0020] Furthermore, in the above technical solution, the roasting atmosphere is selected from argon or nitrogen.
[0021] The third objective of this invention is to provide an application of a three-phase composite material of perovskite, carbon, and alloy particles in the catalytic oxygen evolution reaction process.
[0022] Furthermore, in the above technical solution, the perovskite, carbon, and alloy particle three-phase composite material can be applied to the anodic oxygen evolution reaction in catalytic water splitting.
[0023] The catalyst prepared by the above method and its application in the anodic reaction of catalytic water electrolysis.
[0024] Beneficial effects:
[0025] This invention can synthesize nano-perovskite, carbon, and alloy particle composite materials with uniform carbon layer coating and uniform alloy / metal particle precipitation, which are catalysts with certain electrocatalytic activity. This method uses simple equipment, is easy to operate, and has low cost. Furthermore, the prepared catalyst exhibits excellent OER activity.
[0026] (1) The catalyst prepared by this invention is a nanomaterial with a core-shell structure consisting of a perovskite core, metal / alloy particles deposited on the surface, and a carbon-nitrogen shell. First, the carbon-nitrogen shell provides good electron conduction and prevents the growth of metal / alloy particles. Both the perovskite substrate and the deposited metal / alloy particles can serve as active sites to catalyze the oxygen evolution reaction. The sufficiently small size of the deposited particles can provide more active sites, thereby promoting the improvement of catalytic activity.
[0027] (2) This invention uses dopamine salt as the carbon source for the carbon-nitrogen layer. Dopamine salt can undergo self-polymerization in alkaline solution to form polydopamine, which can be adsorbed onto the surface of most materials, forming a uniform polydopamine coating. The thickness of the polydopamine coating can be controlled by the amount of dopamine salt added and the polymerization time. Uniformly dispersed perovskite materials can also be used as materials for polydopamine adhesion, thereby coating a uniform polydopamine coating onto the perovskite particles. During the carbonization process, the polydopamine coating can reduce the metal from the perovskite structure, thereby dissolving the metal / alloy particles in situ during the carbonization shell formation process. The carbon-nitrogen layer obtained by calcination and carbonization can effectively coat the metal / alloy particles and the perovskite substrate, and improve the electron conduction between particles.
[0028] (3) The catalyst of the present invention has a smaller overpotential than the original perovskite under the same current density, and at the same time has higher catalytic activity, better stability and lower price, and is very promising for catalytic water electrolysis anode reaction. Attached Figure Description
[0029] Figure 1 The polarization curves of perovskites with different carbon and nitrogen shell thicknesses prepared in Example 1 of the present invention are shown below, along with those of the original perovskite.
[0030] Figure 2 The graphs are stability test curves for Examples 1, 2, and 3.
[0031] Figure 3These are XRD patterns of perovskite materials at different stages prepared in Example 1.
[0032] Figure 4 These are scanning electron microscope (SEM) images of the perovskite materials at different stages prepared in Example 1.
[0033] Figure 5 Transmission electron microscopy (TEM) images of perovskites with different carbon-nitrogen shell thicknesses prepared in Examples 1, 2, and 3. Detailed Implementation
[0034] The following embodiments will further illustrate the present invention, but are not intended to limit the invention.
[0035] The preparation of the perovskite material used in this invention is referenced in Perovskites decorated with oxygenvacancies and Fe-Ni alloy nanoparticles as high-efficiency electrocatalysts for the oxygen evolution reaction. J. Mater. Chem. A, 2017, 5, 19836-19845.
[0036] The reference for the dopamine polymerization used in this invention to form a polydopamine coating is Mussel-inspired surface chemistry for multifunctional coatings. Science 2007, 318, 426–430.
[0037] Example 1
[0038] According to the technical solution of this invention, the perovskite selected is Sr2Fe. 1.3 Ni 0.2 Mo 0.5 O 6-δ (SFNM), SEM image of SFNM perovskite in Figure 4 The left figure shows the XRD patterns of SFNM perovskite with particle sizes of 100-200 nm. Figure 3 ( Figure 3As given in section 3), the mass ratio of SFNM perovskite to dopamine salt was 6. 0.2 g of SFNM perovskite was dispersed in 80 ml of a Tris alkaline solution with pH 8.5. The perovskite was ultrasonically dispersed for 1 hour to ensure uniform dispersion and form a suspension. The weighed dopamine salt powder sample was then added to the suspension and dispersed ultrasonically for another 5 minutes. The mixture was then stirred on a magnetic stirrer for 12 hours, centrifuged, washed with water, and freeze-dried to obtain the SFNM-coated polydopamine sample. The scanning electron microscope image of the SFNM-coated polydopamine sample is shown in [reference needed]. Figure 4 The figure in the middle shows that XRD in Figure 3 ( Figure 3 As given in section 2). Subsequently, the SFNM-coated polydopamine layer was calcined at 700°C for 3 hours under an argon atmosphere. This yielded the SFNM perovskite-NiFe alloy-carbon-nitrogen shell three-phase composite material (SFNM-NiFe@C), as shown below. Figure 4 As shown in the right figure, numerous precipitated alloy particles exist on the perovskite surface, and the encapsulating carbon-nitrogen shell masks the grain boundaries between the perovskite grains, demonstrating the good encapsulation properties of the carbon-nitrogen shell. XRD of SFNM-NiFe@C... Figure 3 ( Figure 3 As given in number 1). Figure 5 As shown in (a), TEM revealed a carbon-nitrogen layer thickness of approximately 10 nm, with precipitated alloy particles of approximately 10-20 nm in size. The obtained material was used as the anolyte in the catalytic water electrolysis reaction for electrochemical performance testing. A half-cell method was employed. A 0.1 mol / L potassium hydroxide solution was used as the electrolyte, a platinum wire as the counter electrode, and a saturated calomel electrode as the reference electrode. SFNM-NiFe@C slurry was coated onto a rotating disk electrode, dried, and then tested. The SFNM-NiFe@C test results are shown in... Figure 1 middle( Figure 1 Curve number 1), the SFNM test results are shown in Figure 1 middle( Figure 1 Curve number 4), with the rotation speed set to 1600 rpm, and the oxygen evolution current density at 10 mA / cm²... 2 At this point, the SFNM-NiFe@C potential was 1.66V (vs. RHE). This represents an increase of 40mV compared to uncoated SFNM, indicating a significant improvement in catalytic activity. Stability test results for the original SFNM show... Figure 2 In (a), the stability test results of SFNM-NiFe@C show that... Figure 2 In (b), the results show that the stability of SFNM-NiFe@C (mass ratio = 6) was significantly improved.
[0039] Example 2
[0040] According to the technical solution of this invention, the perovskite selected is Sr2Fe. 1.3 Ni 0.2 Mo 0.5 O 6-δ (SFNM), the mass ratio of SFNM perovskite to dopamine salt was 5. 0.2 g of SFNM perovskite was dispersed in 80 ml of Tris alkaline solution at pH 8.5. The perovskite was ultrasonically dispersed for 1 h to ensure uniform dispersion and form a suspension. The weighed dopamine salt was then added to the suspension, and the mixture was ultrasonically dispersed for another 5 min. The mixture was then stirred on a magnetic stirrer for 12 h, centrifuged, washed with water, and freeze-dried to obtain the SFNM-coated polydopamine coating sample. The SFNM-coated polydopamine coating was then calcined at 700 °C for 3 h under an argon atmosphere. This yielded the SFNM perovskite-NiFe alloy-carbon-nitrogen shell three-phase composite material (SFNM-CoNiFe@C). Figure 5 As shown in (b), TEM revealed a carbon-nitrogen layer thickness of approximately 20 nm. The obtained material was used as the anolyte in the catalytic water electrolysis reaction for electrochemical performance testing. A half-cell method was employed. A 0.1 mol / L potassium hydroxide solution was used as the electrolyte, a platinum wire as the counter electrode, and a saturated calomel electrode as the reference electrode. SFNM-NiFe@C slurry was coated onto a rotating disk electrode, dried, and then tested. The test results show... Figure 1 middle( Figure 1 (Curve number 2). Test results show that when the rotation speed is set to 1600 rpm, and the oxygen evolution current density is 10 mA / cm², 2 At this point, the potential was 1.65V (vs. RHE). This represents an increase of 50mV compared to uncoated SFNM, indicating a significant improvement in catalytic activity. Stability test results show... Figure 2 In (c), the results show that the stability of SFNM-NiFe@C (mass ratio = 5) was significantly improved.
[0041] Example 3
[0042] According to the technical solution of this invention, the perovskite selected is Sr2Fe. 1.3 Ni 0.2 Mo 0.5 O 6-δ(SFNM), the mass ratio of SFNM perovskite to dopamine salt was 4. 0.2 g of SFNM perovskite was dispersed in 80 ml of Tris alkaline solution at pH 8.5. The perovskite was ultrasonically dispersed for 1 h to ensure uniform dispersion and form a suspension. The weighed dopamine salt was then added to the suspension, and the mixture was ultrasonically dispersed for another 5 min. The mixture was then stirred on a magnetic stirrer for 12 h, centrifuged, washed with water, and freeze-dried to obtain the SFNM-coated polydopamine sample. The SFNM-coated polydopamine coating was then calcined at 700 °C for 3 h under an argon atmosphere. This yielded the SFNM perovskite-NiFe alloy-carbon-nitrogen shell three-phase composite material (SFNM-NiFe@C). Figure 5 As shown in (c), TEM revealed a carbon-nitrogen layer thickness of approximately 30 nm. The obtained material was used as the anolyte in the catalytic water electrolysis reaction for electrochemical performance testing. A half-cell method was employed. A 0.1 mol / L potassium hydroxide solution was used as the electrolyte, a platinum wire as the counter electrode, and a saturated calomel electrode as the reference electrode. SFNM-NiFe@C slurry was coated onto a rotating disk electrode, dried, and then tested. The test results show... Figure 1 middle( Figure 1 (Curve number 3). Test results show that when the rotation speed is set to 1600 rpm, and the oxygen evolution current density is 10 mA / cm², 2 At that time, the potential was 1.67V (vs. RHE). This represents an increase of 30mV compared to uncoated SFNM, indicating a significant improvement in catalytic activity. Stability test results show... Figure 2 In (d), the results show that the stability of SFNM-NiFe@C (mass ratio = 4) was significantly improved.
[0043] Example 4
[0044] According to the technical solution of this invention, the perovskite selected is Sr2Fe. 1.3 Co 0.2 Mo 0.5 O 6-δ(SFCM), the mass ratio of SFCM perovskite to dopamine salt was 5. 0.2 g of SFCM perovskite was dispersed in 80 ml of Tris alkaline solution (pH 8.5). The perovskite was ultrasonically dispersed for 1 h to ensure uniform dispersion, forming a suspension. The weighed dopamine salt was then added to the suspension, and the mixture was ultrasonically dispersed for another 5 min. The mixture was then stirred on a magnetic stirrer for 12 h, centrifuged, washed with water, and freeze-dried to obtain the SFCM-coated polydopamine sample. The SFCM-coated polydopamine coating was then calcined at 700 °C for 3 h under an argon atmosphere. This yielded the SFCM perovskite-CoFe alloy-carbon-nitrogen shell three-phase composite material (SFCM-CoFe@C). The obtained material was used as the anolyte for catalytic water electrolysis. The experiment employed a half-cell method. The electrolyte was a 0.1 mol / L potassium hydroxide solution, with a platinum wire as the counter electrode and a saturated calomel electrode as the reference electrode. SFCM-CoFe@C slurry was coated onto a rotating disk electrode and tested after drying. Test results showed that at a rotation speed of 1600 rpm, the oxygen evolution current density was 10 mA / cm². 2 At this point, the potential was 1.65V (vs. RHE). This represents an increase of 50mV compared to the uncoated SFCM, indicating a significant improvement in catalytic activity.
[0045] Example 5
[0046] According to the technical solution of this invention, the perovskite selected is SrTi 0.8 Fe 0.2 O 3-δ (STF), with a mass ratio of STF perovskite to dopamine salt of 5, 0.2 g of STF perovskite was dispersed in 80 ml of Tris alkaline solution at pH 8.5. The perovskite was ultrasonically dispersed for 1 h to ensure uniform dispersion and form a suspension. The weighed dopamine salt was then added to the suspension, and the mixture was ultrasonically dispersed for another 5 min. The mixture was then stirred on a magnetic stirrer for 12 h, centrifuged, washed with water, and freeze-dried to obtain an STF-coated polydopamine-coated sample. The STF-coated polydopamine coating was then calcined at 700 °C for 3 h under an argon atmosphere to obtain the STF perovskite-Fe metal-carbon-nitrogen shell three-phase composite material (STF-Fe@C). The obtained material was used as the anolyte for catalytic water electrolysis. The experiment employed a half-cell method. A 0.1 mol / L potassium hydroxide solution was used as the electrolyte, a platinum wire as the counter electrode, and a saturated calomel electrode as the reference electrode. STF-Fe@C slurry was coated onto a rotating disk electrode and dried before testing. Test results showed that at a rotation speed of 1600 rpm, the oxygen evolution current density was 10 mA / cm². 2At this point, the potential was 1.72V (vs. RHE). This represents an increase of 80mV compared to the uncoated STF, indicating a significant improvement in catalytic activity.
[0047] Example 6
[0048] According to the technical solution of this invention, the perovskite selected is LaTi 0.8 Fe 0.2 O 3-δ (LTF), with a mass ratio of LTF perovskite to dopamine salt of 5, 0.2 g of LTF perovskite was dispersed in 80 ml of Tris alkaline solution at pH 8.5. The perovskite was ultrasonically dispersed for 1 h to ensure uniform dispersion and form a suspension. The weighed dopamine salt was then added to the suspension, and the mixture was ultrasonically dispersed for another 5 min. The mixture was then stirred on a magnetic stirrer for 12 h, centrifuged, washed with water, and freeze-dried to obtain an LTF-coated polydopamine-coated sample. The LTF-coated polydopamine coating was then calcined at 700 °C for 3 h under an argon atmosphere to obtain the LTF perovskite-Fe metal-carbon-nitrogen shell three-phase composite material (LTF-Fe@C). The obtained material was used as the anolyte for catalytic water electrolysis. The experiment employed a half-cell method. A 0.1 mol / L potassium hydroxide solution was used as the electrolyte, a platinum wire as the counter electrode, and a saturated calomel electrode as the reference electrode. LTF-Fe@C slurry was coated onto a rotating disk electrode and dried before testing. Test results showed that at a rotation speed of 1600 rpm, the oxygen evolution current density was 10 mA / cm². 2 At this point, the potential was 1.73V (vs. RHE). This represents an increase of 70mV compared to the uncoated LTF, indicating a significant improvement in catalytic activity.
[0049] Example 7
[0050] According to the technical solution of the present invention, the perovskite selected is Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-δ(BSCF), the mass ratio of BSCF perovskite to dopamine salt was 5. 0.2 g of BSCF perovskite was dispersed in 80 ml of Tris alkaline solution with pH 8.5. The perovskite was ultrasonically dispersed for 1 h to ensure uniform dispersion and form a suspension. The weighed dopamine salt was then added to the suspension, and the mixture was ultrasonically dispersed for another 5 min. The mixture was then stirred on a magnetic stirrer for 12 h, centrifuged, washed with water, and freeze-dried to obtain a BSCF-coated polydopamine sample. The BSCF-coated polydopamine coating was then calcined at 700 °C for 3 h under an argon atmosphere. This yielded a BSCF perovskite-CoFe alloy-carbon-nitrogen shell three-phase composite material (BSCF-CoFe@C). The obtained material was used as the anolyte for catalytic water electrolysis. The experiment employed a half-cell method. A 0.1 mol / L potassium hydroxide solution was used as the electrolyte, a platinum wire as the counter electrode, and a saturated calomel electrode as the reference electrode. BSCF-CoFe@C slurry was coated onto a rotating disk electrode and tested after drying. Test results showed that at a rotation speed of 1600 rpm, the oxygen evolution current density was 10 mA / cm². 2 At this point, the potential was 1.55V (vs. RHE). This represents an increase of 80mV compared to uncoated BSCF, indicating a significant improvement in catalytic activity.
[0051] Example 8
[0052] According to the technical solution of the present invention, the perovskite selected is LaMn 0.7 Co 0.3 O3 (LMC), with a mass ratio of LMC perovskite to dopamine salt of 5, 0.2 g of LMC perovskite was dispersed in 80 ml of Tris alkaline solution at pH 8.5. The perovskite was ultrasonically dispersed for 1 h to ensure uniform dispersion and form a suspension. The weighed dopamine salt was then added to the suspension, and the mixture was ultrasonically dispersed for another 5 min. The mixture was then stirred on a magnetic stirrer for 12 h, centrifuged, washed with water, and freeze-dried to obtain an LMC-coated polydopamine-coated sample. The LMC-coated polydopamine coating was then calcined at 700 °C for 3 h under an argon atmosphere to obtain an LMC-Co@C three-phase composite material (LMC-Co@C). The obtained material was used as the anolyte for catalytic water electrolysis. A half-cell method was employed. A 0.1 mol / L potassium hydroxide solution was used as the electrolyte, a platinum wire as the counter electrode, and a saturated calomel electrode as the reference electrode. LMC-Co@C slurry was coated onto a rotating disk electrode and tested after drying. Test results showed that at a rotation speed of 1600 rpm, the oxygen evolution current density was 10 mA / cm². 2 At this point, the potential was 1.72V (vs. RHE). This represents an increase of 60mV compared to the uncoated LMC, indicating a significant improvement in catalytic activity.
[0053] Example 9
[0054] According to the technical solution of this invention, the perovskite selected is SrCo 0.8 Fe 0.2 O 3-δ (SCF), with a mass ratio of SCF perovskite to dopamine salt of 5, 0.2 g of SCF perovskite was dispersed in 80 ml of Tris alkaline solution at pH 8.5. The perovskite was ultrasonically dispersed for 1 h to ensure uniform dispersion and form a suspension. The weighed dopamine salt was then added to the suspension, and the mixture was ultrasonically dispersed for another 5 min. The mixture was then stirred on a magnetic stirrer for 12 h, centrifuged, washed with water, and freeze-dried to obtain an SCF-coated polydopamine sample. The SCF-coated polydopamine coating was then calcined at 700 °C for 3 h under an argon atmosphere to obtain the SCF perovskite-CoFe alloy-carbon-nitrogen shell three-phase composite material (SCF-CoFe@C). The obtained material was used as the anolyte for catalytic water electrolysis. The experiment employed a half-cell method. A 0.1 mol / L potassium hydroxide solution was used as the electrolyte, a platinum wire as the counter electrode, and a saturated calomel electrode as the reference electrode. SCF-CoFe@C slurry was coated onto a rotating disk electrode and dried before testing. Test results showed that at a rotation speed of 1600 rpm, the oxygen evolution current density was 10 mA / cm². 2 At this point, the potential was 1.68V (vs. RHE). This represents an increase of 70mV compared to the uncoated SCF, indicating a significant improvement in catalytic activity.
[0055] Example 10
[0056] According to the technical solution of the present invention, the perovskite selected is La 0.95 Fe 0.8 Co 0.2 O 3-δ(LFC), with a mass ratio of LFC perovskite to dopamine salt of 5, 0.2 g of LFC perovskite was dispersed in 80 ml of Tris alkaline solution at pH 8.5. The perovskite was ultrasonically dispersed for 1 h to ensure uniform dispersion and form a suspension. The weighed dopamine salt was then added to the suspension, and the mixture was ultrasonically dispersed for another 5 min. The mixture was then stirred on a magnetic stirrer for 12 h, centrifuged, washed with water, and freeze-dried to obtain the LFC-coated polydopamine sample. The LFC-coated polydopamine coating was then calcined at 700 °C for 3 h under an argon atmosphere to obtain the LFC perovskite-CoFe alloy-carbon-nitrogen shell three-phase composite material (LFC-CoFe@C). The obtained material was used as the anolyte for catalytic water electrolysis. The experiment employed a half-cell method. A 0.1 mol / L potassium hydroxide solution was used as the electrolyte, a platinum wire as the counter electrode, and a saturated calomel electrode as the reference electrode. LFC-CoFe@C slurry was coated onto a rotating disk electrode and tested after drying. Test results showed that at a rotation speed of 1600 rpm, the oxygen evolution current density was 10 mA / cm². 2 At this point, the potential was 1.60V (vs. RHE). This represents an increase of 90mV compared to the uncoated LFC, indicating a significant improvement in catalytic activity.
[0057] Example 11
[0058] According to the technical solution of the present invention, the perovskite selected is CaTi 0.96 Ni 0.04 O 2.96 (CTN), the mass ratio of CTN perovskite to dopamine salt was 5. 0.2 g of CTN perovskite was dispersed in 80 ml of Tris alkaline solution (pH 8.5). The perovskite was ultrasonically dispersed for 1 h to ensure uniform dispersion and form a suspension. The weighed dopamine salt was then added to the suspension, and the mixture was ultrasonically dispersed for another 5 min. The mixture was then stirred on a magnetic stirrer for 12 h, centrifuged, washed with water, and freeze-dried to obtain a CTN-coated polydopamine sample. The CTN-coated polydopamine coating was then calcined at 700 °C for 3 h under an argon atmosphere to obtain a CTN-Ni@C perovskite-Ni metal-carbon-nitrogen shell three-phase composite material. The obtained material was used as the anolyte for catalytic water electrolysis. The experiment employed a half-cell method. A 0.1 mol / L potassium hydroxide solution was used as the electrolyte, a platinum wire as the counter electrode, and a saturated calomel electrode as the reference electrode. CTN-Ni@C slurry was coated onto a rotating disk electrode and dried before testing. Test results showed that at a rotation speed of 1600 rpm, the oxygen evolution current density was 10 mA / cm². 2At this point, the potential was 1.70V (vs. RHE). This is 150mV higher than that of uncoated CTN, indicating a significant improvement in catalytic activity.
[0059] Example 12
[0060] According to the technical solution of the present invention, the perovskite selected is La 0.9 Fe 0.92 Ru 0.08 O 3-δ (LFR), with a mass ratio of LFR perovskite to dopamine salt of 5, 0.2 g of LFR perovskite was dispersed in 80 ml of Tris alkaline solution at pH 8.5. The perovskite was ultrasonically dispersed for 1 h to ensure uniform dispersion and form a suspension. The weighed dopamine salt was then added to the suspension, and the mixture was ultrasonically dispersed for another 5 min. The mixture was then stirred on a magnetic stirrer for 12 h, centrifuged, washed with water, and freeze-dried to obtain an LFR-coated polydopamine sample. The LFR-coated polydopamine coating was then calcined at 700 °C for 3 h under an argon atmosphere to obtain the LFR perovskite-RuFe alloy-carbon-nitrogen shell three-phase composite material (LFR-RuFe@C). The obtained material was used as the anolyte for catalytic water electrolysis. The experiment employed a half-cell method. A 0.1 mol / L potassium hydroxide solution was used as the electrolyte, a platinum wire as the counter electrode, and a saturated calomel electrode as the reference electrode. LFR-RuFe@C slurry was coated onto a rotating disk electrode and tested after drying. Test results showed that at a rotation speed of 1600 rpm, the oxygen evolution current density was 10 mA / cm². 2 At this point, the potential was 1.65V (vs. RHE). This represents an increase of 70mV compared to the uncoated LFR, indicating a significant improvement in catalytic activity.
[0061] Example 13
[0062] According to the technical solution of the present invention, the perovskite selected is La 0.9 Mn 0.6 Ni 0.4 O 3-δ(LMN), with a mass ratio of LMN perovskite to dopamine salt of 5, 0.2 g of LMN perovskite was dispersed in 80 ml of Tris alkaline solution at pH 8.5. The perovskite was ultrasonically dispersed for 1 h to ensure uniform dispersion and form a suspension. The weighed dopamine salt was then added to the suspension, and the mixture was ultrasonically dispersed for another 5 min. The mixture was then stirred on a magnetic stirrer for 12 h, centrifuged, washed with water, and freeze-dried to obtain an LMN-coated polydopamine sample. The LMN-coated polydopamine coating was then calcined at 700 °C for 3 h under an argon atmosphere to obtain an LMN-Ni@C three-phase composite material (LMN-Ni@C). The obtained material was used as the anolyte for catalytic water electrolysis. The experiment employed a half-cell method. A 0.1 mol / L potassium hydroxide solution was used as the electrolyte, a platinum wire as the counter electrode, and a saturated calomel electrode as the reference electrode. LMN-Ni@C slurry was coated onto a rotating disk electrode and dried before testing. Test results showed that at a rotation speed of 1600 rpm, the oxygen evolution current density was 10 mA / cm². 2 At this point, the potential was 1.71V (vs. RHE). This represents an increase of 60mV compared to the uncoated LMN, indicating a significant improvement in catalytic activity.
[0063] Example 14
[0064] According to the technical solution of the present invention, the perovskite selected is La 0.45 Sr 0.45 Mn 0.9 Fe 0.1 O 3–δ LSMF (Laminated Lyohydrate Perovskite) was prepared by dispersing 0.2 g of LSMF perovskite in 80 ml of a Tris alkaline solution at pH 8.5 at a mass ratio of 5:5. The perovskite was ultrasonically dispersed for 1 h to ensure uniform dispersion and form a suspension. The weighed dopamine salt was then added to the suspension, and the mixture was ultrasonically dispersed for another 5 min. The mixture was then stirred on a magnetic stirrer for 12 h, centrifuged, washed with water, and freeze-dried to obtain the LSMF-coated polydopamine sample. The LSMF-coated polydopamine coating was then calcined at 700 °C for 3 h under an argon atmosphere to obtain the LSMF-Fe metal-carbon-nitrogen shell three-phase composite material (LSMF-Fe@C). The obtained material was used as the anolyte for catalytic water electrolysis. The experiment employed a half-cell method. A 0.1 mol / L potassium hydroxide solution was used as the electrolyte, a platinum wire as the counter electrode, and a saturated calomel electrode as the reference electrode. LSMF-Fe@C slurry was coated onto a rotating disk electrode and tested after drying. Test results showed that at a rotation speed of 1600 rpm, the oxygen evolution current density was 10 mA / cm². 2At this point, the potential was 1.57V (vs. RHE). This is an increase of 110mV compared to the uncoated LSMF, indicating a significant improvement in catalytic activity.
[0065] Example 15
[0066] According to the technical solution of this invention, the perovskite selected is Sr 0.95 Nb 0.1 Co 0.8 Ni 0.1 O 3-δ (SNCN), SNCN perovskite to dopamine salt in a mass ratio of 5, 0.2 g of SNCN perovskite was dispersed in 80 ml of Tris alkaline solution with pH = 8.5. The perovskite was ultrasonically dispersed for 1 h to ensure uniform dispersion and form a suspension. The weighed dopamine salt was then added to the suspension, and the mixture was ultrasonically dispersed for another 5 min. The mixture was then stirred on a magnetic stirrer for 12 h, centrifuged, washed with water, and freeze-dried to obtain the SNCN-coated polydopamine coating sample. The SNCN-coated polydopamine coating was then calcined at 700 °C for 3 h under an argon atmosphere to obtain the SNCN perovskite-CoNi alloy-carbon-nitrogen shell three-phase composite material (SNCN-CoNi@C). The obtained material was used as the anolyte for catalytic water electrolysis. The experiment employed a half-cell test method. A 0.1 mol / L potassium hydroxide solution was used as the electrolyte, a platinum wire as the counter electrode, and a saturated calomel electrode as the reference electrode. SNCN-CoNi@C slurry was coated onto a rotating disk electrode and tested after drying. Test results showed that at a rotation speed of 1600 rpm, the oxygen evolution current density was 10 mA / cm². 2 At this point, the potential was 1.61V (vs. RHE). This represents an increase of 60mV compared to the uncoated SNCN, indicating a significant improvement in catalytic activity.
[0067] Example 16
[0068] According to the technical solution of the present invention, the perovskite selected is La 0.7 Sr 0.3 Co 0.9 Pd 0.03 O 3-δ(LSCP), the mass ratio of LSCP perovskite to dopamine salt was 5. 0.2 g of LSCP perovskite was dispersed in 80 ml of Tris alkaline solution at pH 8.5. The perovskite was ultrasonically dispersed for 1 h to ensure uniform dispersion and form a suspension. The weighed dopamine salt was then added to the suspension, and the mixture was ultrasonically dispersed for another 5 min. The mixture was then stirred on a magnetic stirrer for 12 h, centrifuged, washed with water, and freeze-dried to obtain an LSCP-coated polydopamine sample. The LSCP-coated polydopamine coating was then calcined at 700 °C for 3 h under an argon atmosphere to obtain the LSCP perovskite-Co metal-carbon-nitrogen shell three-phase composite material (LSCP-Co@C). The obtained material was used as the anolyte for catalytic water electrolysis. The experiment employed a half-cell method. A 0.1 mol / L potassium hydroxide solution was used as the electrolyte, a platinum wire as the counter electrode, and a saturated calomel electrode as the reference electrode. LSCP-Co@C slurry was coated onto a rotating disk electrode and dried before testing. Test results showed that at a rotation speed of 1600 rpm, the oxygen evolution current density was 10 mA / cm². 2 At this point, the potential was 1.62V (vs. RHE). This represents an increase of 110mV compared to the uncoated LSCP, indicating a significant improvement in catalytic activity.
[0069] Example 17
[0070] According to the technical solution of the present invention, the perovskite selected is La 0.8 Sr 0.2 Cr 0.69 Ni 0.31 O 3-δ (LSCN), the mass ratio of LSCN perovskite to dopamine salt was 5. 0.2 g of LSCN perovskite was dispersed in 80 ml of Tris alkaline solution with pH 8.5. The perovskite was ultrasonically dispersed for 1 h to ensure uniform dispersion and form a suspension. The weighed dopamine salt was then added to the suspension, and the mixture was ultrasonically dispersed for another 5 min. The mixture was then stirred on a magnetic stirrer for 12 h, centrifuged, washed with water, and freeze-dried to obtain the LSCN-coated polydopamine coating sample. The LSCN-coated polydopamine coating was then calcined at 700 °C for 3 h under an argon atmosphere. This yielded the LSCN perovskite-CoNi alloy-carbon-nitrogen shell three-phase composite material (LSCN-CoNi@C). The obtained material was used as the anolyte for catalytic water electrolysis. The experiment employed a half-cell method. The electrolyte was a 0.1 mol / L potassium hydroxide solution, with a platinum wire as the counter electrode and a saturated calomel electrode as the reference electrode. LSCN-CoNi@C slurry was coated onto a rotating disk electrode and tested after drying. Test results showed that at a rotation speed of 1600 rpm, the oxygen evolution current density was 10 mA / cm². 2At this point, the potential was 1.64V (vs. RHE). This represents an increase of 140mV compared to the uncoated LSCN, indicating a significant improvement in catalytic activity.
[0071] Many examples can be listed above. The applicant’s extensive experimental data proves that as long as it is within the scope of the technical solution of this invention, a three-phase composite material of perovskite, carbon and alloy particles can be successfully prepared for catalytic water electrolysis anode reaction.
Claims
1. A three-phase composite material of perovskite, carbon, and alloy particles, characterized in that, Metal or alloy particles are precipitated in situ from perovskite particles, and a carbon-nitrogen shell is coated on the perovskite and the precipitated metal or alloy particles. The metal in the metal or alloy particles is selected from at least one of iron, cobalt, nickel, copper, and molybdenum.
2. The perovskite, carbon, and alloy particle three-phase composite material according to claim 1, characterized in that, The perovskite has a size of 100-200 nm; the carbon-nitrogen shell has a thickness of 10 ± 2 nm, and the thickness is adjustable.
3. A method for preparing the three-phase composite material of perovskite, carbon, and alloy particles as described in claim 1 or 2, characterized in that, Includes the following steps: (1) Prepare a Tris alkaline solution, add the perovskite material to the Tris alkaline solution, disperse it, and obtain a dispersion; (2) Add dopamine salt to the dispersion obtained in step (1) and disperse it. Then place it on a stirrer and stir for 6-24 hours. After that, centrifuge and freeze dry. (3) The product obtained in step (2) is roasted in a roasting atmosphere to obtain the perovskite, carbon and alloy particle three-phase composite material.
4. The preparation method according to claim 3, characterized in that, The perovskite material is a perovskite-structured oxide with the chemical formula ABO3; wherein the metal at the A site is an alkaline earth metal, the metal at the B site is a transition metal, and the A and B sites are a single metal or a complex combination of several metals; the number of complex combinations of metals is two to three, and the total number of metal elements in the perovskite material is two to four.
5. The preparation method according to claim 4, characterized in that, The alkaline earth metals include beryllium, magnesium, calcium, strontium, and barium; the transition metals include iron, cobalt, nickel, copper, and molybdenum.
6. The preparation method according to claim 3, characterized in that, The perovskite material has a diameter of 100-200 nm; the perovskite material can be uniformly dispersed in water and can maintain stability in water; the mass ratio of the perovskite material to dopamine salt is 20-4.
7. The preparation method according to claim 3, characterized in that, The pH of the Tris alkaline solution is 8-9, and the calcination temperature is 700-800℃ for 3-4 hours.
8. The preparation method according to claim 3, characterized in that, During the polymerization of the dopamine salt in an alkaline solution, the polymerization time can be adjusted to control the thickness of the dopamine coating, thereby regulating the thickness of the carbon-nitrogen shell after carbonization. The polymerization time is directly proportional to the thickness of the dopamine coating, with a polymerization time of 3-24 hours and a corresponding coating thickness of 5-50 nm.
9. The application of the perovskite, carbon, and alloy particle three-phase composite material as described in claim 1 or 2, characterized in that, The perovskite, carbon, and alloy particle three-phase composite material is used in the process of catalytic oxygen evolution reaction.
10. The application according to claim 9, characterized in that, The perovskite, carbon, and alloy particle three-phase composite material is used in the anodic oxygen evolution reaction of catalytic water splitting.