A hydroxide-phosphide heterojunction oxygen evolution catalyst, its preparation method, and its application in electrolyzing seawater

Abstract

The present invention provides a hydroxide-phosphide heterojunction oxygen evolution catalyst, a preparation method thereof, and an application thereof in electrolyzing seawater, belonging to the field of electrolyzing seawater. In order to solve the problems of serious corrosion during the electrolysis of seawater, weak conductivity during electrolysis, which restricts the rapid transfer of electrons and leads to low catalytic efficiency. The method includes ultrasonic cleaning of a carrier material; preparing a first precursor solution from an ammonium salt, a phosphorus source, and a metal source for preparing a phosphide; depositing a metal phosphide on the surface of the carrier by an electrochemical deposition method; preparing a second precursor solution from a metal source for preparing a hydroxide; growing a layered metal hydroxide on the surface of the metal phosphide by an electrochemical deposition method to obtain a metal hydroxide-phosphide heterojunction catalyst; and obtaining a layered metal hydroxide / phosphide heterojunction oxygen evolution catalyst after cleaning and drying. The present invention is simple, efficient, and low-cost, and can prepare a more efficient oxygen evolution reaction catalyst, which has a good inhibitory effect on the chlorine evolution reaction.

Description

Technical Field

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

[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, conducting 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 a huge challenge 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. 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 RuO2, IrO2) have good catalytic activity for OER, their high cost and resource scarcity severely restrict large-scale commercial applications. Therefore, developing non-precious 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, making them 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 conductivity and abundant active sites, and the presence of phosphorus can regulate the electronic structure of metals, enhancing 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 the improvement of OER reaction kinetics. 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 different anions into the interlayers to regulate the interlayer spacing. Despite the above advantages, these materials still face some challenges in practical applications. For TMPs, oxidation or dissolution of metal phosphides may occur during long-term electrolysis, resulting in a decline in catalytic performance. For LDHs, their poor 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:

[0007] To solve the problems of serious corrosion in the existing electrolysis of seawater, weak conductivity during the electrolysis process, which limits the rapid transfer of electrons and results in low overall catalytic efficiency.

[0008] The technical solution adopted by the present invention to solve the above technical problems:

[0009] The present invention provides a preparation method of a hydroxide-phosphide heterojunction oxygen evolution catalyst, comprising the following steps:

[0010] S100. Ultrasonically clean the carrier material, remove surface impurities, and dry for later use;

[0011] S200. Dissolve an ammonium salt, a phosphorus source, and a metal source for preparing phosphide in deionized water to form a first precursor solution;

[0012] S300. In the first precursor solution prepared in step S200, deposit metal phosphide on the surface of the carrier by electrochemical deposition;

[0013] S400. Dissolve the metal source for preparing hydroxide in deionized water to form a second precursor solution;

[0014] S500. In the second precursor solution prepared in step S400, a layered metal hydroxide is grown on the surface of the metal phosphide prepared in step S300 by an electrochemical method to obtain a metal hydroxide-phosphide heterojunction catalyst;

[0015] S600. Wash the metal hydroxide-phosphide heterojunction catalyst, and after drying, obtain a layered metal hydroxide / phosphide heterojunction catalyst, that is, a hydroxide-phosphide heterojunction oxygen evolution catalyst;

[0016] 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 nitrate second precursor solution is prepared, and CoCuP is used as a working electrode, and Ce@NiFe LDH is grown on its surface to obtain a heterojunction catalyst Ce@NiFe LDH / CoCuP (C@NFL / CCP).

[0017] 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.

[0018] Further, in step S200, the ammonium salt is one or a combination of ammonium chloride, ammonium sulfate, ammonium nitrate or ammonium carbonate; the phosphorus source is one or a combination 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 a combination 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.

[0019] Further, the ratio of the ammonium salt, the phosphorus source and the metal source for preparing the phosphide is 1:1-50:1.

[0020] Further, in steps S300 and 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 0.5 V-5 V, and the deposition time is 2 min-60 min for both.

[0021] Further, the concentration of the metal source for preparing the hydroxide is 0.1-1.0 mol / L.

[0022] Further, in step S600, the cleaning agent used for cleaning is one or a combination of deionized water, ethanol, or acetone.

[0023] Further, in step S600, the drying temperature range is 25°C - 100°C.

[0024] Further, the present invention protects a hydroxide-phosphide heterojunction oxygen evolution catalyst prepared by the above preparation method.

[0025] Further, the present invention protects the application of a hydroxide-phosphide heterojunction oxygen evolution catalyst in electrolyzing seawater.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] 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 by the present invention has a good inhibitory effect on the chlorine evolution reaction, and 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, which is the fundamental reason for achieving a significant improvement in OER activity while effectively inhibiting the chlorine evolution reaction; at the same time, the heterojunction catalyst has good structural tunability, and by changing the types of metal elements, different types of heterojunction catalysts can be regulated and synthesized.

[0028] The material synthesis technology of the present invention only needs a simple two-step electrodeposition method to synthesize a 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 heterojunctions; during the synthesis process, the LDHs layer grows on the surface of the TMPs and forms an M1-O-M2 atomic interface (M1 and M2 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 phosphides and single-layered metal hydroxides. Description of the Drawings

[0029] Figure 1 It 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;

[0030] Figure 2EDS results of each element in the C@NFL / CCP heterojunction catalyst prepared in Example 1 of the present invention, where Energy is used to qualitatively identify the element types, and cps is used to semi-quantitatively reflect the relative content of the reactive elements;

[0031] Figure 3 XRD spectra 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, where 2Theta is the diffraction angle and Intensity is the photoelectron signal intensity;

[0032] Figure 4 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 spectrum of the Ni active site, (b) is the X-ray photoelectron spectrum of the Co active site, Binding energy is the binding energy, and Intensity is the photoelectron signal intensity;

[0033] Figure 5 Polarization curves of alkaline seawater oxidation of the catalysts prepared in Examples 1-3 and Comparative Examples 1-3 of the present invention;

[0034] Figure 6 Comparison results of oxygen evolution and chlorine resistance performance of the catalysts prepared in Examples 1-3 and Comparative Examples 1-3;

[0035] 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;

[0036] 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 the current density. Detailed implementation manners

[0037] 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 will be given with reference to the accompanying drawings.

[0038] Example 1: The present invention provides a method for preparing a hydroxide-phosphide heterojunction oxygen evolution catalyst, which includes the following steps:

[0039] S100. First, place commercial nickel foam (sized 1 cm * 2 cm * 1 mm) in acetone and ultrasonically clean it for 15 min. Subsequently, place it in 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 and dry it overnight at 70 °C to obtain the treated nickel foam;

[0040] S200. Prepare an electrolyte aqueous solution containing 25 mmol / L of CoCl2, 25 mmol / L of CuCl2, 0.25 mol / L of NH4Cl, 0.5 mol / L of NaPO2H2, and 5 mmol / L of C2H3NaO2 as the precursor solution;

[0041] 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 min; continuously stir during the deposition process. After the deposition is completed, repeatedly rinse the working electrode 3 times with ethanol and deionized water, and then place it in a vacuum drying oven at 70 °C and dry it overnight to obtain the CoCuP electrode;

[0042] S400. Prepare an electrolyte aqueous solution containing 27 mmol / L of Ni(NO)3, 9 mmol / L of Fe(NO)3O, and 3 mmol / L of Ce(NO)3 as the precursor solution;

[0043] 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 min;

[0044] S600. Continuously stir during the deposition process. After the deposition is completed, repeatedly rinse the working electrode 3 times with ethanol and deionized water, and then place it in a vacuum drying oven at 70 °C and dry it overnight to obtain the Ce@NiFe LDH / CoCuP heterojunction catalyst, abbreviated as C@NFL / CCP.

[0045] Example 2: The present invention provides a method for preparing a hydroxide - phosphide heterojunction oxygen evolution catalyst, including the following steps:

[0046] S100. First, place commercial nickel foam (with dimensions of 1 cm * 2 cm * 1 mm) in acetone and ultrasonically clean it for 15 min. Subsequently, 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 and dry it overnight at 70 °C to obtain the treated nickel foam;

[0047] S200. Prepare an electrolyte aqueous solution containing 25 mmol / L of CoCl2, 25 mmol / L of NH4VO3, 0.25 mol / L of NH4Cl, 0.5 mol / L of NaPO2H2, and 5 mmol / L of C2H3NaO2 as the precursor solution;

[0048] S300. The way to deposit phosphide is by constant current deposition, which is carried out in a two - electrode system; use a Ti sheet as the counter electrode and a clean blank NF as the working electrode, and deposit at a constant current of 50 mA cm -2 for 1 min; continuously stir during the deposition process. After the deposition is completed, repeatedly rinse the working electrode 3 times with ethanol and deionized water, and then place it in a vacuum drying oven at 70 °C and dry it overnight to obtain the CoVP electrode;

[0049] 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;

[0050] S500. The way to deposit layered metal hydroxide is by constant voltage deposition, which is carried out in a three - electrode system; use a Pt sheet as the counter electrode, CoVP / NF as the working electrode, and Ag / AgCl as the reference electrode, and deposit at a constant voltage of 1 V for 10 min;

[0051] S600. Continuously stir during the deposition process. After the deposition is completed, repeatedly rinse the working electrode 3 times with ethanol and deionized water, and then place it in a vacuum drying oven at 70 °C and dry it overnight to obtain the Ce@NiFe LDH / CoVP heterojunction catalyst, abbreviated as C@NFL / CVP.

[0052] Example 3: The present invention provides a method for preparing a hydroxide - phosphide heterojunction oxygen evolution catalyst, including the following steps:

[0053] S100. First, place commercial nickel foam (with dimensions of 1 cm * 2 cm * 1 mm) in acetone and ultrasonically clean it for 15 min. Subsequently, 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 and dry it at 70 °C overnight to obtain the treated nickel foam;

[0054] S200. Prepare an electrolyte aqueous solution containing 25 mmol / L of CoCl2, 25 mmol / L of Na2MoO4, 0.25 mol / L of NH4Cl, 0.5 mol / L of NaPO2H2, and 5 mmol / L of C2H3NaO2 as the precursor solution;

[0055] S300. The method of depositing phosphide is constant current deposition, which is carried out in a two-electrode system; use a Ti sheet as the counter electrode and a clean blank NF as the working electrode, and deposit at a constant current of 50 mA cm -2 for 1 min; continuously stir during the deposition process. After the deposition is completed, repeatedly rinse the working electrode with ethanol and deionized water 3 times, and then place it in a vacuum drying oven at 70 °C and dry it overnight to obtain the CoMoP electrode;

[0056] S400. Prepare an electrolyte aqueous solution containing 27 mmol / L of Ni(NO)3·6H2O, 9 mmol / L of Fe(NO)3, and 3 mmol / L of Ce(NO)3 as the precursor solution;

[0057] S500. The method of depositing layered metal hydroxide is constant voltage deposition, which is carried out in a three-electrode system; use a Pt sheet as the counter electrode, CoMoP / NF as the working electrode, and Ag / AgCl as the reference electrode, and deposit at a constant voltage of 1 V for 10 min;

[0058] S600. Continuously stir during the deposition process. After the deposition is completed, repeatedly rinse the working electrode with ethanol and deionized water 3 times, and then place it in a vacuum drying oven at 70 °C and dry it overnight to obtain the Ce@NiFe LDH / CoMoP heterojunction catalyst, abbreviated as C@NFL / CMP.

[0059] Comparative Example 1: A method for preparing a Ce@NiFe LDH oxygen evolution electrocatalyst includes the following steps:

[0060] The Ce@NiFe LDH electrode was deposited by constant voltage deposition in a three-electrode system. An aqueous electrolyte solution containing 27 mmol / L of Ni(NO)3·6H2O, 9 mmol / L of Fe(NO)3 and 3 mmol / L of Ce(NO)3 was prepared as the precursor solution. A Pt sheet was used as the counter electrode, a clean NF was used as the working electrode, and Ag / AgCl was used as the reference electrode. The deposition was carried out at a constant voltage of 1 V for 10 min. The solution was continuously stirred during the deposition process. After the deposition, the working electrode was rinsed repeatedly with ethanol and deionized water three times, and then dried overnight in a vacuum drying oven at 70 °C to obtain the Ce@NiFe LDH electrode.

[0061] Comparative Example 2: A method for preparing a CoCuP oxygen evolution electrocatalyst includes the following steps:

[0062] The CoCuP electrode was deposited by constant current deposition in a two-electrode system. An aqueous electrolyte solution containing 25 mmol / L of CoCl2, 25 mmol / L of Na2MoO4, 0.25 mol / L of NH4Cl, 0.5 mol / L of NaPO2H2 and 5 mmol / L of C2H3NaO2 was prepared as the precursor solution; a Ti sheet was used as the counter electrode, and a clean blank NF was used as the working electrode. The deposition was carried out at a constant current of 50 mA cm -2 for 1 min. The solution was continuously stirred during the deposition process. After the deposition, the working electrode was rinsed repeatedly with ethanol and deionized water three times, and then dried overnight in a vacuum drying oven at 70 °C to obtain the CoCuP electrode.

[0063] Comparative Example 3: A method for preparing a RuO2 oxygen evolution electrocatalyst includes the following steps:

[0064] 10 mg of RuO2 powder and 30 μL of 5 wt.% Nafion solution were dispersed in 970 μL of absolute ethanol and sonicated for at least 30 min to obtain a homogeneous mixture. Subsequently, 50 μL of the mixture was dropped onto a 1 cm * 2 cm nickel foam and the operation was repeated twice. Then it was placed in a vacuum drying oven at 70 °C for drying and waiting for testing.

[0065] Control experiment

[0066] The electrocatalysts prepared in Examples 1-3 and Comparative Examples 1-3 were applied to an electrolyte of 1 M KOH + real seawater for electrocatalytic seawater oxidation testing.

[0067] Detection experiment:

[0068] The electrocatalytic oxygen evolution reaction (OER) and chlorine resistance performance of all the above catalyst materials were tested in a standard three-electrode electrolytic cell. The real seawater was 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. The Pt sheet was used as the counter electrode, Hg / HgO was used as the reference electrode, and the catalysts obtained in the examples and comparative examples were used as the working electrodes. The cyclic scanning range was 0 - 1 V Hg / HgO, and the scanning rate was 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 were 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 (100mA cm -2 ) represents the electrolysis carried out under a constant current of 100 mA / cm 2 , and the Faraday efficiency of O2 was calculated.

[0069] The catalysts prepared in Examples 1 - 3 and Comparative Examples 1 - 3 were used as the 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 diaphragm 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 two-channel peristaltic pump was used to pump the 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 condition for the polarization curve was 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.

[0070] Table 1 Summary of electrocatalytic oxygen evolution and chlorine resistance performance results

[0071]

[0072] Note: η 10 , η 100 represent the overpotentials required when the polarization currents reach 10 and 100 mA / cm 2 respectively; FE O2(100 mA cm -2 ) represents the electrolysis carried out under a constant current of 100 mA / cm 2 , and the Faraday efficiency of O2 was calculated after the electrolysis ended.

[0073] Combined with Figure 1 As 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.

[0074] Combined with Figure 2 As 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.

[0075] Combined with Figure 3 As shown, in the XRD pattern of Comparative Example 2, the characteristic peaks at 23.1° and 43.9° correspond to the (200) and (321) crystal planes of CoP3, respectively, while the characteristic peak at 27.9° corresponds to the (211) crystal plane of Cu3P, which indicates that CoCuP was successfully synthesized in Comparative Example 2. In Comparative Example 1, the XRD pattern of Ce@NiFe LDH shows 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 can be observed, further confirming the successful synthesis of the heterojunction catalyst.

[0076] 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@NiFeLDH 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.

[0077] 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 (RuO2). In addition, the catalytic activities of Example 1, Example 2 and Example 3 are basically the same, and this result indicates 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.

[0078] Combined with Figure 6As 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 (RuO2). 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). This result indicates that the optimization of the oxygen evolution selectivity of the catalyst can be effectively achieved by regulating the types of metal sources.

[0079] Combined Figure 8 As shown, the electrochemical stability and durability of the catalyst during long-term operation can be comprehensively evaluated. During the continuous operation for 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.

[0080] Although the present invention is disclosed as above, the protection scope 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 invention, and these changes and modifications will all fall within the protection scope of the present invention.

Claims

1. Application of a hydroxide-phosphide heterojunction oxygen evolution catalyst in electrolysis of seawater, characterized in that, The preparation method of the hydroxide-phosphide heterojunction oxygen evolution catalyst comprises the following steps: S100. Ultrasonically clean the carrier material, remove surface impurities, and dry for later use; the carrier is nickel foam; S200. Dissolve an ammonium salt, a phosphorus source, and a metal source for preparing phosphide in deionized water to form a first precursor solution; the ratio of the ammonium salt, the phosphorus source, and the metal source for preparing phosphide is 1:1-50:1; S300. In the first precursor solution prepared in step S200, deposit metal phosphide on the surface of the carrier by an electrochemical deposition method; the metal phosphide is CoCuP, CoVP, or CoMoP; S400. Dissolve the metal source for preparing hydroxide in deionized water to form a second precursor solution; the concentration of the metal source for preparing hydroxide is 0.1-1.0 mol / L; S500. In the second precursor solution prepared in step S400, grow layered metal hydroxide on the surface of the metal phosphide deposited in step S300 by an electrochemical deposition method to obtain a metal hydroxide-phosphide heterojunction catalyst; S600. Wash the metal hydroxide-phosphide heterojunction catalyst obtained in step S500, and dry it to obtain a layered metal hydroxide / phosphide heterojunction catalyst, that is, a hydroxide-phosphide heterojunction oxygen evolution catalyst; the hydroxide-phosphide heterojunction oxygen evolution catalyst is a Ce@NiFe LDH / CoCuP heterojunction catalyst, a Ce@NiFe LDH / CoVP heterojunction catalyst, or a Ce@NiFe LDH / CoMoP heterojunction catalyst; In steps S300 and S500, the electrochemical deposition method is either 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 0.5 V - 5 V; the deposition time is 2 min - 60 min for both cases.

2. Use of a hydroxide-phosphide heterojunction oxygen evolution catalyst according to claim 1 in electrolysis of seawater, characterized in that: In step S200, the ammonium salt is one or a combination of more of ammonium chloride, ammonium sulfate, ammonium nitrate, or ammonium carbonate; the phosphorus source is one or a combination of more of sodium hydrogen phosphate, sodium dihydrogen phosphate, potassium hydrogen phosphate, potassium dihydrogen phosphate, or sodium hypophosphite; the metal source for preparing phosphide and the metal source for preparing hydroxide are each one or a combination of more of metal element chloride salts, nitrate salts, sulfate salts, nitrite salts, carbonate salts, or acetate salts.

3. Use of a hydroxide-phosphide heterojunction oxygen evolution catalyst according to claim 2 in electrolysis of seawater, characterized in that: In step S600, the cleaning agent used for washing is one or a combination of more of deionized water, ethanol, or acetone.

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