Hydroxide-phosphide heterojunction oxygen evolution catalyst, preparation method thereof and application of hydroxide-phosphide heterojunction oxygen evolution catalyst in seawater electrolysis

Abstract

The invention provides a hydroxide-phosphide heterojunction oxygen evolution catalyst, a preparation method thereof and application of the hydroxide-phosphide heterojunction oxygen evolution catalyst in seawater electrolysis, and belongs to the field of seawater electrolysis. The invention aims to solve the problem of low catalytic efficiency caused by limitation of rapid transmission of electrons due to severe corrosion of electrolyzed seawater and weak conductivity during electrolysis. The method includes ultrasonically cleaning carrier materials; preparing a first precursor solution from ammonium salt, a phosphorus source and a metal source for preparing phosphide; depositing metal phosphide on the surface of the carrier through an electrochemical deposition method; preparing a second precursor solution from a metal source for preparing hydroxide; the preparation method comprises the following steps: growing layered metal hydroxide on the surface of metal phosphide through an electrochemical deposition method to obtain a metal hydroxide-phosphide heterojunction catalyst; and cleaning and drying to obtain the layered metal hydroxide / phosphide heterojunction oxygen evolution catalyst. The method is simple, efficient and low in cost, the more efficient oxygen evolution reaction catalyst can be prepared, and the good inhibition effect on the chlorine evolution reaction is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of electrolytic seawater, and in particular, to a hydroxide-phosphide heterojunction oxygen evolution catalyst, a preparation method thereof, and an application in electrolytic seawater. Background Technique

[0002] As an ideal energy carrier with high energy density and zero carbon emission, hydrogen can replace traditional fossil fuels and alleviate global warming. In addition, the wide application of hydrogen in fields such as industry, transportation, and energy storage helps to promote the development of the hydrogen energy economy, optimize the energy structure, and enhance energy security. Therefore, carrying out research and application on water electrolysis for hydrogen production is of great significance for achieving green and low-carbon development, addressing climate change, and promoting energy transformation. Seawater resources account for approximately 96.5% of the total world water resources, and electrocatalytic seawater decomposition for hydrogen production is more attractive than freshwater electrolysis.

[0003] Although seawater electrolysis has potential advantages, its complex composition poses great challenges to efficient and sustainable electrolysis. During the process of seawater electrolysis for hydrogen production, the presence of chloride ions (Cl - -) is an important challenge. Chloride ions are oxidized at the anode (ClOR), competing with the oxygen evolution reaction (OER), reducing the hydrogen production rate, and also corroding the catalyst, affecting its stability and service life; in addition, the OER reaction rate is slow and the overpotential is high, resulting in low energy efficiency and being the rate-limiting step in the hydrogen production process by electrolysis. Therefore, developing electrocatalysts with high oxygen evolution activity and strong chlorine resistance is crucial for promoting the wide application of green hydrogen energy. Currently, although noble metal oxides (such as RuO 2 , IrO 2 ) have good catalytic activity for OER, their high cost and scarce resources severely restrict large-scale commercial applications. Therefore, developing non-noble metal-based OER catalysts has become the research focus. Catalytic materials based on transition metals such as nickel, cobalt, and iron not only have low costs but also excellent catalytic performance and are suitable for large-scale applications.

[0004] Transition metal phosphides (TMPs) and layered double hydroxides (LDHs) exhibit excellent oxygen evolution reaction (OER) activity. TMPs have high electrical conductivity and abundant active sites, and the presence of phosphorus can regulate the electronic structure of metals and enhance catalytic activity. LDHs are known for their unique layered structure and high specific surface area, which provide a large number of active sites and are beneficial to improving the kinetics of the OER reaction. LDHs also have excellent structural tunability, and their electrocatalytic performance can be optimized by introducing different metal ions into the layers to regulate the electronic structure and introducing different anions between the layers to adjust the layer spacing. Despite these advantages, these materials still face some challenges in practical applications. For TMPs, oxidation or dissolution of metal phosphides may occur during long-term electrolysis, leading to a decrease in catalytic performance. For LDHs, their poor electrical conductivity limits the rapid transfer of electrons and affects the overall catalytic efficiency.

[0005] Therefore, it is urgent to find simple and feasible process methods to overcome the above defects of TMPs and LDHs in order to further improve their practicality in large-scale electrolytic water hydrogen production. Summary of the Invention

[0006] The technical problem to be solved by the present invention is: To solve the problems of serious corrosion in the existing electrolysis of seawater, weak electrical conductivity during the electrolysis process, which limits the rapid transfer of electrons and results in low overall catalytic efficiency.

[0007] The technical solution adopted by the present invention to solve the above technical problems: The present invention provides a method for preparing a hydroxide-phosphide heterojunction oxygen evolution catalyst, comprising the following steps: S100. Ultrasonically clean the carrier material, remove surface impurities, and dry for later use; S200. Dissolve an ammonium salt, a phosphorus source, and a metal source for preparing phosphide in deionized water to form a first precursor solution; S300. In the first precursor solution prepared in step S200, deposit metal phosphide on the surface of the carrier by an electrochemical deposition method; S400. Dissolve the metal source for preparing hydroxide in deionized water to form a second precursor solution; S500. In the second precursor solution prepared in step S400, grow layered double hydroxide on the surface of the metal phosphide prepared in step S300 by an electrochemical method to obtain a metal hydroxide-phosphide heterojunction catalyst; S600. Clean the metal hydroxide-phosphide heterojunction catalyst, and after drying, obtain a layered double hydroxide / phosphide heterojunction catalyst, that is, a hydroxide-phosphide heterojunction oxygen evolution catalyst; That is, a metal hydroxide-phosphide heterojunction catalyst is prepared by a two-step electrodeposition method. First, a CoCuP electrode is prepared from a first precursor solution. Secondly, a second precursor solution of nitrate is prepared, and CoCuP is used as the working electrode, and Ce@NiFe LDH is grown on its surface to obtain the heterojunction catalyst Ce@NiFe LDH / CoCuP (C@NFL / CCP).

[0008] Further, in step S100, the carrier is a conductive material, and the conductive material is a transition metal, an alloy material or a carbon material.

[0009] Further, in step S200, the ammonium salt is one or more combinations of ammonium chloride, ammonium sulfate, ammonium nitrate or ammonium carbonate; the phosphorus source is one or more combinations of sodium monohydrogen phosphate, sodium dihydrogen phosphate, potassium monohydrogen phosphate, potassium dihydrogen phosphate or sodium hypophosphite; the metal source for preparing the phosphide and the metal source for preparing the hydroxide are both one or more combinations of metal element chlorides, nitrates, sulfates, nitrites, carbonates or acetates. The metal element in the metal source for preparing the phosphide is Co, Cu, Mo, V, Cr or Mn, and the metal element in the metal source for preparing the hydroxide is Ni, Fe, Ce, La, Al or K.

[0010] Further, the ratio of the ammonium salt, the phosphorus source and the metal source for preparing the phosphide is 1:1-50:1.

[0011] Further, in steps S300 and S500, the electrodeposition method is constant current deposition or constant voltage deposition. When the electrodeposition method is constant current deposition, the constant current range is 50 mA / cm 2 -500 mA / cm 2 , and when the electrodeposition method is constant voltage deposition, the constant voltage range is 0.5 V-5 V, and the deposition time is 2 min-60 min.

[0012] Further, the concentration of the metal source for preparing the hydroxide is 0.1-1.0 mol / L.

[0013] Further, in step S600, the cleaning agent used for cleaning is one or more combinations of deionized water, ethanol or acetone.

[0014] Further, in step S600, the drying temperature range is 25°C-100°C.

[0015] Further, the present invention protects a hydroxide-phosphide heterojunction oxygen evolution catalyst prepared by the above preparation method.

[0016] Furthermore, the present invention protects the application of a hydroxide-phosphide heterojunction oxygen evolution catalyst in electrolyzing seawater.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: Since seawater contains abundant chloride ions, the chlorine evolution reaction will lead to the generation of highly corrosive chlorine-containing by-products. However, the heterojunction catalyst prepared in the present invention has a good inhibitory effect on the chlorine evolution reaction, which can effectively slow down the corrosion of the electrode and the electrolysis device; in the heterojunction catalyst, the phosphide acts as an electron buffer layer, which can optimize the electronic structure of the active species layered metal hydroxide. This is the fundamental reason for the significant improvement of OER activity while effectively inhibiting the chlorine evolution reaction; at the same time, the heterojunction catalyst has good structural tunability. By changing the types of metal elements, different types of heterojunction catalysts can be synthesized. The material synthesis technology of the present invention only needs a simple two-step electrodeposition method to synthesize the layered metal hydroxide / phosphide heterojunction catalyst, which greatly shortens the time cost and reduces the difficulty of material synthesis, providing a new idea for the preparation of layered metal hydroxide / phosphide heterojunction; during the synthesis process, the LDHs layer grows on the surface of the TMPs and forms an M 1 -O-M 2 atomic interface (M 1 and M 2 are the metal elements in the LDHs and TMPs respectively), enhancing the stability of the heterojunction catalyst; the OER activity and stability of the heterojunction catalyst are significantly improved compared with single phosphide and single-layered metal hydroxide. Description of the Drawings

[0018] Figure 1 Figure 21 is a scanning electron microscope (SEM) image of C@NFL / CCP prepared in Example 1 of the present invention. Among them, (a) is the electron microscope at a resolution of 500 nm Figure 1 , (b) is the electron microscope at a resolution of 500 nm Figure 2 , (c) is the electron microscope image at a resolution of 200 nm; Figure 2 Figure 28 is an energy dispersive spectroscopy (EDS) result image of each element in the C@NFL / CCP heterojunction catalyst prepared in Example 1 of the present invention. Among them, Energy is used to qualitatively identify the types of elements, and cps is used to semi-quantitatively reflect the relative content of elements; Figure 3 Figure 31 is an X-ray diffraction (XRD) spectrum of C@NFL / CCP, Ce@NiFe LDH, and CoCuP catalysts prepared in Example 1, Comparative Example 1, and Comparative Example 2 of the present invention. Among them, 2Theta is the diffraction angle, and Intensity is the photoelectron signal intensity; Figure 4 X-ray photoelectron spectroscopy (XPS) analysis results of the C@NFL / CCP, Ce@NiFe LDH, and CoCuP catalysts prepared in Example 1, Comparative Example 1, and Comparative Example 2 of the present invention. Among them, (a) is the X-ray photoelectron spectroscopy of Ni active sites, (b) is the X-ray photoelectron spectroscopy of Co active sites, Binding energy is the binding energy, and Intensity is the photoelectron signal intensity; Figure 5 Linear sweep voltammetry curves of the catalysts prepared in Examples 1-3 and Comparative Examples 1-3 of the present invention in alkaline seawater; Figure 6 Oxygen evolution chlorine resistance performance comparison results of the catalysts prepared in Examples 1-3 and Comparative Examples 1-3; Figure 7 Schematic diagram of the membrane electrode assembly (MEA) for the stability test of the C@NFL / CCP catalyst in Example 1 of the present invention; Figure 8 Stability test results of C@NFL / CCP in the MEA assembly in Example 1 of the present invention, where Time is time and Current density is current density. Detailed implementation manners

[0019] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following detailed description of the specific embodiments of the present invention is provided in conjunction with the accompanying drawings.

[0020] Example 1: The present invention provides a method for preparing a hydroxide-phosphide heterojunction oxygen evolution catalyst, which includes the following steps: S100: First, commercially available nickel foam (size: 1 cm * 2 cm * 1 mm) is ultrasonically cleaned in acetone for 15 min, then ultrasonically cleaned in a 1 mol / L HCl aqueous solution for 15 min, and finally ultrasonically cleaned with ethanol and deionized water for 10 min each, and then placed in a vacuum drying oven at 70 °C for drying overnight to obtain the treated nickel foam; S200: Prepare a precursor solution containing 25 mmol / L CoCl 2 , 25 mmol / L CuCl 2 , 0.25 mol / L NH 4 Cl, 0.5 mol / L NaPO 2 H 2 and 5 mmol / L C 2 H 3 NaO 2 as the electrolyte aqueous solution; S300. The method of depositing phosphide is constant current deposition, which is carried out in a two-electrode system. Using a Ti sheet as the counter electrode and a clean blank NF as the working electrode, deposit at a constant current of 50 mA cm -2 for 1 minute. Stir continuously during the deposition process. After the deposition is completed, rinse the working electrode with ethanol and deionized water repeatedly for 3 times, and then place it in a vacuum drying oven at 70 °C to dry overnight to obtain the CoCuP electrode; S400. Prepare an electrolyte aqueous solution containing 27 mmol / L of Ni(NO) 3 , 9 mmol / L of Fe(NO) 3 O and 3 mmol / L of Ce(NO) 3 as the precursor solution; S500. The method of depositing layered metal hydroxide is constant voltage deposition, which is carried out in a three-electrode system. Using a Pt sheet as the counter electrode, CoCuP / NF as the working electrode, and Ag / AgCl as the reference electrode, deposit at a constant voltage of 1 V for 10 minutes; S600. Stir continuously during the deposition process. After the deposition is completed, rinse the working electrode with ethanol and deionized water repeatedly for 3 times, and then place it in a vacuum drying oven at 70 °C to dry overnight to obtain the Ce@NiFe LDH / CoCuP heterojunction catalyst, abbreviated as C@NFL / CCP.

[0021] Example 2: The present invention provides a method for preparing a hydroxide-phosphide heterojunction oxygen evolution catalyst, including the following steps: S100. First, place commercial foam nickel (size 1 cm * 2 cm * 1 mm) in acetone and ultrasonically clean it for 15 minutes, then place it in a 1 mol / L HCl aqueous solution and ultrasonically clean it for 15 minutes. Finally, ultrasonically clean it with ethanol and deionized water for 10 minutes each, and then put it into a vacuum drying oven at 70 °C to dry overnight to obtain the treated foam nickel; S200. Prepare an electrolyte aqueous solution containing 25 mmol / L of CoCl 2 , 25 mmol / L of NH 4 VO 3 , 0.25 mol / L of NH 4 Cl, 0.5 mol / L of NaPO 2 H 2 and 5 mmol / L of C 2 H 3 NaO 2 as the precursor solution; S300. The way to deposit phosphide is by constant current deposition, which is carried out in a two - electrode system. Using a Ti sheet as the counter electrode and a clean blank NF as the working electrode, deposit at a constant current of 50 mA cm -2 for 1 min. Stir continuously during the deposition process. After the deposition is completed, rinse the working electrode 3 times repeatedly with ethanol and deionized water, and then place it in a vacuum drying oven at 70 °C to dry overnight, thus obtaining the CoVP electrode; S400. Prepare an electrolyte aqueous solution containing 27 mmol / L of Ni(NO) 3 , 9 mmol / L of Fe(NO) 3 and 3 mmol / L of Ce(NO) 3 as the precursor solution; S500. The way to deposit layered metal hydroxide is by constant voltage deposition, which is carried out in a three - electrode system. Using a Pt sheet as the counter electrode, CoVP / NF as the working electrode, and Ag / AgCl as the reference electrode, deposit at a constant voltage of 1 V for 10 min; S600. Stir continuously during the deposition process. After the deposition is completed, rinse the working electrode 3 times repeatedly with ethanol and deionized water, and then place it in a vacuum drying oven at 70 °C to dry overnight, thus obtaining the Ce@NiFe LDH / CoVP heterojunction catalyst, abbreviated as C@NFL / CVP.

[0022] Example 3: The present invention provides a method for preparing a hydroxide - phosphide heterojunction oxygen evolution catalyst, which includes the following steps: S100. First, place commercial foam nickel (with dimensions of 1 cm * 2 cm * 1 mm) in acetone and ultrasonically clean it for 15 min, then place it in a 1 mol / L HCl aqueous solution and ultrasonically clean it for 15 min. Finally, ultrasonically clean it with ethanol and deionized water for 10 min each, and then put it into a vacuum drying oven at 70 °C to dry overnight, thus obtaining the treated foam nickel; S200. Prepare an electrolyte aqueous solution containing 25 mmol / L of CoCl 2 , 25 mmol / L of Na 2 MoO 4 , 0.25 mol / L of NH 4 Cl, 0.5 mol / L of NaPO 2 H 2 and 5 mmol / L of C 2 H 3 NaO 2 as the precursor solution; S300. The way to deposit phosphide is constant current deposition, which is carried out in a two-electrode system. Using a Ti sheet as the counter electrode and a clean blank NF as the working electrode, deposit at a constant current of 50 mA cm -2 for 1 minute. Stir continuously during the deposition process. After the deposition is completed, rinse the working electrode with ethanol and deionized water repeatedly for 3 times, and then place it in a vacuum drying oven at 70 °C to dry overnight to obtain the CoMoP electrode; S400. Prepare an electrolyte aqueous solution containing 27 mmol / L of Ni(NO) 3 ·6H 2 O, 9 mmol / L of Fe(NO) 3 and 3 mmol / L of Ce(NO) 3 as the precursor solution; S500. The way to deposit layered double hydroxides is constant voltage deposition, which is carried out in a three-electrode system. Using a Pt sheet as the counter electrode, CoMoP / NF as the working electrode, and Ag / AgCl as the reference electrode, deposit at a constant voltage of 1 V for 10 minutes; S600. Stir continuously during the deposition process. After the deposition is completed, rinse the working electrode with ethanol and deionized water repeatedly for 3 times, and then place it in a vacuum drying oven at 70 °C to dry overnight to obtain the Ce@NiFe LDH / CoMoP heterojunction catalyst, abbreviated as C@NFL / CMP.

[0023] Comparative Example 1: A preparation method of a Ce@NiFe LDH oxygen evolution electrocatalyst includes the following steps: The way to deposit the Ce@NiFe LDH electrode is constant voltage deposition, which is carried out in a three-electrode system. Prepare an electrolyte aqueous solution containing 27 mmol / L of Ni(NO) 3 ·6H 2 O, 9 mmol / L of Fe(NO) 3 and 3 mmol / L of Ce(NO) 3 as the precursor solution. Using a Pt sheet as the counter electrode, a clean NF as the working electrode, and Ag / AgCl as the reference electrode, deposit at a constant voltage of 1 V for 10 minutes. Stir continuously during the deposition process. After the deposition is completed, rinse the working electrode with ethanol and deionized water repeatedly for 3 times, and then place it in a vacuum drying oven at 70 °C to dry overnight to obtain the Ce@NiFe LDH electrode.

[0024] Comparative Example 2: A preparation method of a CoCuP oxygen evolution electrocatalyst includes the following steps: The way to deposit the CoCuP electrode is constant current deposition, which is carried out in a two-electrode system. Prepare a solution containing 25 mmol / L of CoCl 2 , 25 mmol / L of Na2 MoO 4 , 0.25 mol / L of NH 4 Cl, 0.5 mol / L of NaPO 2 H 2 and 5 mmol / L of C 2 H 3 NaO 2 aqueous electrolyte solution as the precursor solution; using a Ti sheet as the counter electrode and a clean blank NF as the working electrode, with a constant current of 50 mA cm -2 for 1 min. Stir continuously during the deposition process. After the deposition, rinse the working electrode with ethanol and deionized water repeatedly for 3 times, and then place it in a vacuum drying oven at 70 °C to dry overnight to obtain the CoCuP electrode.

[0025] Comparative Example 3: A method for preparing a RuO 2 oxygen evolution electrocatalyst includes the following steps: Disperse 10 mg of RuO 2 powder and 30 μL of 5wt.% Nafion solution in 970 μL of absolute ethanol, sonicate for at least 30 min to obtain a uniform mixture. Then take 50 μL of the mixture and drop-coat it on a 1 cm * 2 cm nickel foam, repeat the operation twice, and place it in a vacuum drying oven at 70 °C to dry for testing.

[0026] Control experiment Apply the electrocatalysts prepared in Examples 1 - 3 and Comparative Examples 1 - 3 to an electrolyte of 1 M KOH + real seawater for electrocatalytic seawater oxidation testing.

[0027] Detection experiment: Perform electrocatalytic oxygen evolution (OER) and chlorine resistance tests on all the above catalyst materials in a standard three-electrode electrolytic cell. The real seawater is taken from the natural Bohai Bay in Huludao City, Liaoning Province, with a water depth of 5 - 10 meters, a north latitude of 40.6, and a longitude of 120.8. A Pt sheet is used as the counter electrode, and Hg / HgO is used as the reference electrode. The catalysts obtained in the examples and comparative examples are used as the working electrodes. The cyclic scanning range is 0~1 V Hg / HgO, and the scanning rate is 2 mV / s. The results are shown in Table 1. It should be noted that all the electrode potentials obtained with the Hg / HgO electrode as the reference electrode in the electrocatalytic tests are converted to the reversible hydrogen electrode potential in the performance result summary table (Table 1); η10 and η100 in the table represent the overpotentials required when the polarization currents reach 10 and 100 mA / cm 2 respectively; FE O2 (100 mA cm -2 ) means electrolysis is carried out at a constant current of 100 mA / cm 2 to calculate O2 Faraday efficiency.

[0028] The catalysts prepared in Examples 1-3 and Comparative Examples 1-3 were used as anodes. As Figure 7 shown, C@NFL / CCP prepared in Examples 1-3 was used as the anode, and carbon felt (Pt / C) was used as the cathode. The overall water splitting reaction was carried out in a membrane electrode assembly. The separator material at the centers of the anode and cathode was Nafion 117 proton exchange membrane, and the outer parts of the anode and cathode were Gasket (sealing gasket) and Plate (bipolar plate), respectively. The specific test conditions were as follows: the effective areas of the anode and cathode were 2 cm 2 , and a dual-channel peristaltic pump was used to pump seawater electrolyte containing 1 mol / L KOH into the serpentine flow channels of the anode and cathode plates at a flow rate of 50 mL / min; the test conditions for the polarization curve were 20 mV / s; after electrolysis at 2.0 V for 10 min, the cathode gas product was collected, and the purity of the hydrogen product was tested by gas chromatography. The results are shown in Table 1.

[0029] Table 1 Summary of the results of electrocatalytic oxygen evolution and chlorine resistance performance

[0030] Note: η 10 , η 100 represent the overpotentials required for the polarization currents to reach 10 and 100 mA / cm 2 respectively; FE O2(100 mA cm -2 ) represents electrolysis at a constant current of 100 mA / cm 2 , and after the electrolysis is completed, the Faraday efficiency of O 2 is calculated.

[0031] Combined with Figure 1 shown, the surface of the catalyst synthesized by the method of the present invention presents an interlaced nanosheet structure. This unique structure not only endows the catalyst with a large specific surface area, which helps to expose more active sites, but also the voids between them promote the penetration and mass transfer process of the electrolyte. These characteristics work together to significantly improve the reaction activity of the catalyst.

[0032] Combined with Figure 2 shown, the characteristic peaks of Ce, Ni, Fe, O, Co, Cu, and P elements can be clearly observed, and this result confirms the successful synthesis of the heterojunction catalyst.

[0033] Combined with Figure 3 shown, in the XRD pattern of Comparative Example 2, the characteristic peaks at 23.1° and 43.9° correspond to CoP 3The (200) and (321) crystal planes, while the characteristic peak at 27.9° corresponds to Cu 3 The (211) crystal plane of P indicates that CoCuP was successfully synthesized in Comparative Example 2. In Comparative Example 1, the XRD pattern of Ce@NiFe LDH showed broad and weak characteristic peaks at 23.0°, 34.4°, and 60.0°, corresponding to the (006), (012), and (110) crystal planes of LDH, respectively. In addition, in the XRD pattern of the heterojunction catalyst prepared in Example 1, the characteristic peaks of all the above crystal planes could be observed, further confirming the successful synthesis of the heterojunction catalyst.

[0034] Combined with Figure 4 As shown, the binding energy of the Ni active sites in C@NFL / CCP is more moderate compared to that of Ce@NiFe LDH obtained in Comparative Example 1, indicating that its electronic structure is in a more optimal state. This optimized electronic structure is beneficial to improving the charge transfer efficiency in the catalytic reaction, thus endowing C@NFL / CCP with more excellent electrocatalytic activity.

[0035] Combined with Figure 5 As shown, the catalytic activity of the C@NFL / CCP catalyst prepared in Example 1 is significantly higher than that of Comparative Example 1 (Ce@NiFe LDH), Comparative Example 2 (CoCuP), and Comparative Example 3 (RuO 2 ). In addition, the catalytic activities of Example 1, Example 2, and Example 3 are basically the same, indicating that the heterojunction preparation method proposed in this application has wide universality and can be applied to the construction and optimization of different catalytic systems.

[0036] Combined with Figure 6 As shown, the oxygen evolution selectivity of the C@NFL / CCP catalyst prepared in Example 1 is significantly better than that of Comparative Example 1 (Ce@NiFe LDH), Comparative Example 2 (CoCuP), and Comparative Example 3 (RuO 2 ). At the same time, the oxygen evolution selectivity of C@NFL / CCP is slightly higher than that of Example 2 (C@NFL / CVP) and Example 3 (C@NFL / CMP), indicating that the oxygen evolution selectivity of the catalyst can be effectively optimized by regulating the types of metal sources.

[0037] Combined with Figure 8 As shown, the electrochemical stability and durability of the catalyst during long-term operation can be comprehensively evaluated. During the continuous operation of up to 200 hours, C@NFL / CCP can continuously output a stable current density without obvious performance decay. This result fully demonstrates that the catalyst has excellent electrochemical stability and shows great potential in the practical application of industrial water electrolysis.

[0038] Although the present invention is disclosed as above, the scope of protection of the present invention is not limited thereto. Those skilled in the art of the present invention can make various changes and modifications without departing from the spirit and scope of the present disclosure, and these changes and modifications will all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a hydroxide-phosphide heterojunction oxygen evolution catalyst, characterized in that: The following steps are involved: S100, ultrasonically cleaning the carrier material to remove surface impurities, and drying for later use; S200, dissolving an ammonium salt, a phosphorus source, and a metal source for preparing a phosphide in deionized water to form a first precursor solution; S300, depositing a metal phosphide on the surface of a support by an electrochemical deposition method in the first precursor solution prepared in step S200; S400, dissolving a metal source for preparing a hydroxide in deionized water to form a second precursor solution; S500, growing a layered metal hydroxide on the surface of the metal phosphide deposited in step S300 by an electrochemical deposition method in the second precursor solution prepared in step S400 to obtain a metal hydroxide-phosphide heterojunction catalyst; S600, washing the metal hydroxide-phosphide heterojunction catalyst obtained in step S500, and drying to obtain a layered metal hydroxide / phosphide heterojunction catalyst, namely, a hydroxide-phosphide heterojunction oxygen evolution catalyst.

2. The method for preparing a hydroxide-phosphide heterojunction oxygen evolution catalyst according to claim 1, characterized in that: In step S100, the carrier is a conductive material, and the conductive material is a transition metal, an alloy material or a carbon material.

3. The method for preparing a hydroxide-phosphide heterojunction oxygen evolution catalyst according to claim 2, characterized in that: In step S200, the ammonium salt is one or more combinations of ammonium chloride, ammonium sulfate, ammonium nitrate or ammonium carbonate; the phosphorus source is one or more combinations of sodium monohydrogen phosphate, sodium dihydrogen phosphate, potassium monohydrogen phosphate, potassium dihydrogen phosphate or sodium hypophosphite; the metal source used to prepare the phosphide and the metal source used to prepare the hydroxide are both one or more combinations of chlorides, nitrates, sulfates, nitrites, carbonates or acetates of metal elements.

4. The method for preparing a hydroxide-phosphide heterojunction oxygen evolution catalyst according to claim 3, characterized in that: The metal element in the metal source for preparing the phosphide is Co, Cu, Mo, V, Cr or Mn, and the metal element in the metal source for preparing the hydroxide is Ni, Fe, Ce, La, Al or K.

5. The method for preparing a hydroxide-phosphide heterojunction oxygen evolution catalyst according to claim 4, characterized in that: The ratio of the ammonium salt, the phosphorus source and the metal source for preparing the phosphide is 1:1-50:

1.

6. The method for preparing a hydroxide-phosphide heterojunction oxygen evolution catalyst according to claim 5, characterized in that: In step S300 and step S500, the electrochemical deposition method is constant current deposition or constant voltage deposition. When the electrochemical deposition method is constant current deposition, the constant current range is 50 mA / cm 2 -500 mA / cm 2 ; When the electrochemical deposition method is constant voltage deposition, the constant voltage range is 0.5V-5 V; the deposition time is 2min-60 min.

7. The method for preparing a hydroxide-phosphide heterojunction oxygen evolution catalyst according to claim 6, characterized in that: The concentration of the metal source used to prepare the hydroxide is 0.1-1.0 mol / L.

8. The method for preparing a hydroxide-phosphide heterojunction oxygen evolution catalyst according to claim 7, characterized in that: In step S600, the cleaning agent used for cleaning is one or more combinations of deionized water, ethanol or acetone.

9. A hydroxide-phosphide heterojunction oxygen evolution catalyst, wherein the hydroxide-phosphide heterojunction oxygen evolution catalyst is prepared by the method according to any one of claims 1 to 8.

10. Use of the hydroxide-phosphide heterogeneous oxygen evolution catalyst according to claim 9 in electrolysis of seawater.

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