A material containing a passivation layer structure and a method for its production and use

Abstract

The application belongs to the technical field of electrode materials, and particularly relates to a material containing a passivation layer structure and a preparation method and application thereof. The material comprises: a metal phosphide / metal sulfide / metal silicate in the interior, a surface passivation layer coated on the surface of the material, and an intermediate passivation layer between the metal phosphide / metal sulfide / metal silicate and a metal oxide; the surface passivation layer is a first metal oxide layer or a composite passivation layer; the intermediate passivation layer is selected from one or more layers of a second metal oxide layer and a non-metal anion salt layer; and the metal phosphide / metal sulfide / metal silicate is a metal phosphide, a metal sulfide or a metal silicate. The application first proposes the application of a multilayer composite metal oxide and non-metal anion salt passivation layer structure in the prevention of oxidation and corrosion on the anode side of water / sea water electrolysis and the coupling of fluctuation renewable energy hydrogen evolution on the cathode side.

Description

Technical Field

[0001] This invention belongs to the field of electrode material technology, specifically relating to a material containing a passivation layer structure, its preparation method, and its applications. Background Technology

[0002] Hydrogen energy, as a clean, efficient energy source with high mass energy density, is considered a promising energy carrier and the best alternative to traditional fossil fuels. Among various hydrogen production methods, using renewable energy to electrolyze water is considered an effective way to obtain green hydrogen. However, freshwater resources account for less than 3% of global water resources. Limited by freshwater reserves, using renewable energy coupled with seawater electrolysis is a more sustainable approach. Furthermore, using renewable energy coupled with seawater electrolysis to produce hydrogen can fully utilize the abundant renewable energy reserves at sea, enabling the development of floating electrolysis hydrogen production in coastal or deep-sea areas.

[0003] However, electrolysis of water / seawater under industrial current coupled with renewable energy faces a series of challenges. At the anode of the water / seawater electrolysis system, continuous oxidation under high current leads to a sustained increase in the valence state of metal species sites, even to the point of over-oxidation. When the potential exceeds the peroxidation potential of the metal species, the metal sites are oxidized into high-valence metal salts that dissolve in the electrolyte, resulting in the deactivation of active sites. When seawater or concentrated brine is used as the electrolyte feed, the large amount of Br₂ present in seawater... - Cl - Impurity ions tend to move towards the anode during electrolysis, adsorbing onto the substrate surface and corroding it. Simultaneously, chloride ions participate in a competing chlorination side reaction at the anode. For water / seawater electrolysis cathodes, researchers have traditionally evaluated their catalytic stability using constant current stability tests. Under these conditions, the cathode catalyst remains in a reduced state, less affected by oxidation current and impurity anions in the solution. However, few have considered the volatile, intermittent, and unstable characteristics of renewable energy sources. Summary of the Invention

[0004] The applicant discovered that during frequent start-up and shutdown tests of renewable energy coupled with water / seawater electrolysis, a reverse current phenomenon occurred between the anode and cathode. When the electrolyzer stopped operating, reverse currents existed between the anode and cathode, with the cathode potential gradually increasing from negative to positive, and the oxidation potential even exceeding the theoretical potential for water decomposition. Continuously applying this oxidation potential leads to the deactivation of the cathode's metal active sites. When the potential exceeds the oxidation potential of the metal sites, hydroxide precipitates form, which are difficult to reduce during hydrogen evolution. More seriously, the feed composition of the coupled seawater causes a large number of present halide anions to tend towards the cathode during the reverse process, resulting in cathode corrosion. The applicant believes this may be a key reason for the poor compatibility between alkaline water electrolysis and alkaline membrane water electrolysis with renewable energy.

[0005] Therefore, understanding and designing the passivation layer structure to resist excessive oxidation under high anode current and corrosion problems under seawater as feedstock, and to alleviate corrosion and oxidation problems under frequent cathode start-up and shutdown conditions, is crucial for the development of hydrogen production through water electrolysis / seawater coupled with renewable energy. It may even potentially solve the mismatch between alkaline water electrolysis and alkaline membrane water electrolysis and renewable energy. Previous studies have not clarified the microscopic passivation layer structure and its formation mechanism, and the mechanisms of oxidation resistance and corrosion resistance of the passivation layer are not well understood and require further clarification. Based on this, this invention proposes a material containing a multilayer passivation layer structure composed of metal oxides and non-metal anionic salts generated in situ. The high oxygen coordination number combination of metal oxides and non-metal anionic salts can form a dense, layered passivation layer structure, effectively resisting the migration and diffusion of oxygen species into the bulk phase, thereby terminating excessive oxidation during the high anode potential and cathode start-up and shutdown reverse processes. Meanwhile, the phosphates / sulfides / silicates generated in situ during the oxidation process can be adsorbed on the electrode surface, effectively resisting the corrosion of the substrate by halide ions under oxidation potential, and can enhance the passivation effect. It can be widely used in frequent start-up and shutdown scenarios of anodes and cathodes in water / seawater electrolysis.

[0006] The first aspect of the present invention provides a material containing a passivation layer structure, the material comprising: a metal phosphide / metal sulfide / metal silicate located inside, a surface passivation layer covering the surface of the material, and an intermediate passivation layer between the metal phosphide / metal sulfide / metal silicate and the metal oxide;

[0007] The surface passivation layer is a first metal oxide layer or a composite passivation layer;

[0008] The intermediate passivation layer is selected from one or more layers of: a second metal oxide layer and a non-metal anion salt layer;

[0009] The composite passivation layer is: a mixed layer containing a first metal oxide and a second metal oxide, a mixed layer containing a first metal oxide and a non-metal anionic salt, or a mixed layer containing a first metal oxide, a non-metal anionic salt, and a second metal oxide.

[0010] The metal phosphide / metal sulfide / metal silicate is a metal phosphide, metal sulfide, or metal silicate.

[0011] Preferably, the metal in the metal phosphide / metal sulfide / metal silicate is selected from one or more of nickel, cobalt, iron, vanadium, chromium, and manganese;

[0012] The first metal oxide is selected from one or more of the following: chromium oxide, manganese oxide, zirconium oxide, cerium oxide, niobium oxide, tantalum oxide, and vanadium oxide; the metal in the first metal oxide is in a valence state of +3 or higher.

[0013] Preferably, the first metal oxide is selected from one or more of the following: chromium trioxide, manganese dioxide, zirconium dioxide, cerium dioxide, niobium pentoxide, tantalum pentoxide, and vanadium pentoxide.

[0014] Preferably, the non-metallic anionic salt layer is selected from one or more of sulfate, phosphate, and silicate layers;

[0015] The second metal oxide layer is selected from one or more of the following: vanadium oxide layer, nickel oxide layer, cobalt oxide layer, chromium oxide layer, manganese oxide layer, and iron oxide layer.

[0016] Preferably, the metal in the second metal oxide layer is selected from the metal phosphide / metal sulfide / metal silicate.

[0017] Preferably, when the material includes the metal phosphide, the non-metallic anionic salt layer includes a phosphate layer;

[0018] When the material includes the metal sulfide, the nonmetallic anionic salt layer includes a sulfate layer;

[0019] When the material includes the metal silicate, the non-metallic anionic salt layer includes a silicate layer.

[0020] Preferably, the total thickness of the surface passivation layer and the intermediate passivation layer is 5-40 nanometers.

[0021] A second aspect of this application provides a method for preparing a material containing a passivation layer structure, the method comprising the following steps:

[0022] Step A: Provide heterojunction materials;

[0023] The heterojunction material comprises: a metal phosphide / metal sulfide / metal silicate and a metal oxide nanoarray; the metal phosphide / metal sulfide / metal silicate and the metal oxide form a heterojunction;

[0024] The metal phosphide / metal sulfide / metal silicate is a metal phosphide, a metal sulfide, or a metal silicate;

[0025] Step B: The heterojunction material is used as the cathode for electrolysis of water / seawater under frequent start-stop conditions, or the heterojunction material is used as the anode for electrolysis of water / seawater under oxidation potential. In this way, a passivation layer is generated in situ on the heterojunction material, and the material described in the first aspect is obtained.

[0026] Preferably, the electrolyte for the electrolysis of water is water, or an aqueous solution containing alkali metal hydroxides.

[0027] The electrolyte for the electrolysis of seawater is an aqueous solution containing alkali metal hydroxides and alkali metal halides.

[0028] When the heterojunction material is used as the cathode for electrolysis of water / seawater under frequent start-stop conditions, the voltage of the cathode continues to rise after the current is terminated, which is called the reversal phenomenon. The passivation layer is formed during the reversal process.

[0029] The passivation layer begins to form when the cathode voltage rises to around 0.8 volts. The final passivation layer structure varies depending on the final voltage. For example, in this embodiment, if the cathode voltage continues to rise to 1.09 volts or 1.3 volts, the final passivation layer structure will be two or three layers.

[0030] The third aspect of this application provides the application of the material containing the passivation layer structure of the first aspect in the electrolysis of water / seawater oxygen evolution.

[0031] The fourth aspect of this application provides the application of the material containing the passivation layer structure of the first aspect in hydrogen evolution of water / seawater coupled with wave energy.

[0032] In this application, the method for preparing the heterojunction nanoarray material includes the following steps:

[0033] The preparation of the metal phosphide / metal sulfide / metal silicate nanoarray and the composite of the metal oxide;

[0034] The preparation of the metal phosphide / metal sulfide / metal silicate nanoarray includes the following steps:

[0035] Step A: Prepare metal phosphide / metal sulfide / metal silicate nanoarray precursors using a hydrothermal method or electrodeposition method;

[0036] The hydrothermal method includes the following steps: adding metal salt and urea to water and dissolving them to obtain a solution, then transferring the solution to a hydrothermal reactor for hydrothermal reaction;

[0037] The electrodeposition method includes the following steps: adding a metal salt to water to obtain a solution, using a conductive substrate as a cathode, and placing the anode and a reference electrode in the solution to carry out an electrodeposition reaction;

[0038] The metal salt is selected from one or more of nickel salts, cobalt salts, iron salts, vanadium salts, chromium salts, and manganese salts;

[0039] Step B: Phosphate, sulfide, or silicate the metal phosphide / metal sulfide / metal silicate nanoarray precursor obtained in Step A to obtain the metal phosphide / metal sulfide / metal silicate nanoarray.

[0040] The phosphating process includes steps selected from one of the following two methods:

[0041] Method 1: Place the metal phosphide / metal sulfide / metal silicate nanoarray precursor obtained in step A in a magnetic boat and place it downstream of a tube furnace. Place sodium hypophosphite in another magnetic boat and place it upstream of a tube furnace for calcination.

[0042] Method 2: Place the metal phosphide / metal sulfide / metal silicate nanoarray precursor obtained in step A in a magnetic boat, place it in a vacuum furnace, evacuate to negative pressure, then introduce a mixture of 10% phosphine and 90% nitrogen, and purge the tube furnace until the gauge pressure is zero, then calcine at 300~450 degrees Celsius for 2~3 hours.

[0043] The vulcanization process includes one of the following three steps:

[0044] Method 1: Place ethanol, thiourea, and the metal phosphide / metal sulfide / metal silicate nanoarray precursor obtained in step A into a hydrothermal reactor for hydrothermal reaction;

[0045] Method 2: Place the metal phosphide / metal sulfide / metal silicate nanoarray precursor obtained in step A in a magnetic boat and place it downstream of a tube furnace. Place sulfur powder in another magnetic boat and place it upstream of the tube furnace for calcination.

[0046] Method 3: Place water, sodium sulfide, and the metal phosphide / metal sulfide / metal silicate nanoarray precursor obtained in step A into a hydrothermal reactor for hydrothermal reaction;

[0047] The silicate formation includes the following steps: adding nonahydrate, sodium silicate, and sodium hydroxide to a mixed solution of ethanol and water, such that the concentrations of nonahydrate and sodium silicate are 10-20 mmol, and the concentration of sodium hydroxide is 5-10 mmol; then placing the metal phosphide / metal sulfide / metal silicate nanoarray precursor obtained in step A into a hydrothermal reactor and reacting at 120-160°C for 8-15 hours.

[0048] The composite of the metal oxides is carried out through the following steps:

[0049] Step (1), Electrodeposition: A metal salt aqueous solution of 5~600 mmol / L is used as the electrodeposition solution. The metal phosphide / metal sulfide / metal silicate nanoarray obtained in step B above is used as the working electrode, and a stainless steel mesh is used as the counter electrode. A constant current electrodeposition reaction is carried out using a two-electrode system. The constant current electrodeposition current density is set to -1 ~ -100 mA / cm², and the electrodeposition time is set to 5~3600 seconds.

[0050] The metal salt includes one or more of the following: chromium salt, manganese salt, zirconium salt, cerium salt, niobium salt, tantalum salt, and vanadium salt.

[0051] Step (2), calcination:

[0052] The material obtained in step (1) is placed in a magnetic boat and then placed in a tube furnace. The furnace is calcined under a nitrogen or inert gas atmosphere at a temperature of 250-400 degrees Celsius for 2-3 hours.

[0053] The features of this application are:

[0054] The multilayer passivation layer structure is generated in situ under oxidation potential. The passivation layer consists of a metal oxide layer and a non-metal anionic salt layer, and can be two, three, four, or more layers.

[0055] The passivation layer can be dynamically adjusted according to working conditions: when the oxidation potential of the metal is lower than that of the non-metal anionic salt, the metal preferentially forms a passivation layer, followed by the non-metal anionic salt; when the oxidation potential of the metal is higher than that of the non-metal anionic salt, the non-metal anionic salt preferentially forms a passivation layer, followed by the metal forming an oxide passivation layer.

[0056] The surface coating consists of one or more high-valence species such as chromium trioxide, manganese dioxide, zirconium dioxide, niobium pentoxide, cerium dioxide, tantalum pentoxide, and vanadium pentoxide, which can form a dense oxide layer and play the same role as the passivation layer.

[0057] Compared with the prior art, the present invention has the following beneficial effects:

[0058] 1. This invention is the first to propose the application of a multilayer composite metal oxide and non-metal anionic salt passivation layer structure in the electrolysis of water / seawater for oxidation prevention and corrosion resistance on the anode side and coupling of fluctuating renewable energy hydrogen evolution on the cathode side. Thanks to the dense oxide layer formed by the stacking of metal oxide and salt layers, the oxygen tunneling barrier is increased, thereby terminating oxidation at the interface between the passivation layer and the active site. Simultaneously, the phosphate / sulfate / silicate anions generated in situ during the oxidation process of phosphides / sulfides / silicates can be adsorbed on the electrode surface, utilizing charge repulsion and steric hindrance effects to repel the large amounts of halide ions present in seawater, protecting the electrode from corrosion and poisoning by halide ions.

[0059] The passivation layer is a combination of metal oxides and non-metallic anionic salts. Taking nickel cobalt phosphide-chromium trioxide heterojunction material as an example, the passivation layer is formed in situ by the nickel cobalt phosphide-chromium trioxide heterojunction material under oxidation potential. The oxidation potential of metallic cobalt is lower than that of the non-metallic anionic phosphorus, and the oxidation potential of phosphorus is lower than that of metallic cobalt. During the oxidation process, metallic cobalt is preferentially oxidized to form a cobalt oxide layer. As the potential continues to increase to reach the phosphorus oxidation potential, a phosphate passivation layer begins to form. Phosphate or cobalt oxide can also be superimposed with the surface chromium trioxide layer to form a denser oxide layer, while terminating the over-oxidation of the metal passivation layer and preventing the excessive oxidation and dissolution of the metallic cobalt passivation layer during the oxidation process. At the same time, the chromium oxide interface constructed on the surface can effectively enrich the outermost oxide layer, ultimately forming a multi-layered passivation layer structure and terminating oxidation.

[0060] 2. The embodiments of this application demonstrate:

[0061] Utilizing this passivation layer structure, the nickel-cobalt phosphide-chromium trioxide heterojunction electrode can achieve 1000 hours of fluctuation-resistant operation in intermittent electrolytic hydrogen evolution coupled with renewable energy, at a current density of 0.5 amperes per square centimeter in an alkaline real seawater environment, with a start-stop frequency of 12 hours per cycle, and a voltage decay rate of less than 0.5% per thousand hours. This is attributed to the nickel-cobalt phosphide-chromium trioxide heterojunction electrode preferentially forming a multi-layer passivation layer structure during the start-stop reversal process, resisting excessive oxidation of the cathode by the discharge current and protecting the zero-valent active sites. Furthermore, the phosphate ions generated in situ during the oxidation process can be adsorbed on the electrode surface and applied to the intermittent electrolysis of seawater for hydrogen evolution coupled with renewable energy, resisting the corrosion and poisoning of the cathode by the large number of halide ions present in seawater. Conversely, Comparative Example 1 demonstrates that the nickel-cobalt layered double hydroxide electrode, lacking a dense oxide layer formed by the combination of phosphate and metal oxides, is easily oxidized during frequent start-stop cycles. At a current density of 0.5 amps per square centimeter in an alkaline real seawater environment, operating at a frequency of 12 hours per start-stop cycle for 800 hours resulted in a voltage decay rate of 20.58%. This indicates that the nickel-cobalt layered double hydroxide electrode, lacking a dense passivation layer formed by the combination of phosphates, cannot continuously resist oxidation during the reverse process, leading to deactivation of active sites and voltage decay. Furthermore, while the formation of the passivation layer is crucial in the reverse process of coupled renewable energy water electrolysis / seawater cathode, the restoration of the passivation layer during hydrogen evolution is equally important, affecting whether the electrode can continuously evolve hydrogen. To test the adaptability of the passivation layer structure to ultra-frequent fluctuations, this invention conducted electrolytic hydrogen evolution under ultra-frequent fluctuations of 1 amps per square centimeter in alkaline real seawater with 10-minute start-stop cycles. The results show that the passivation layer structure can operate stably for 500 hours without voltage decay under these harsh conditions.

[0062] To test the corrosion resistance of the passivation layer structure in brine, the electrode was subjected to anti-fluctuation operation in alkaline saturated brine at a current density of 0.2 amperes per square centimeter, with a start-stop frequency of 12 hours. The results showed that the passivation layer structure formed in situ on the electrode facilitated 450 hours of anti-fluctuation operation, with a voltage decay of only 1.52% and no significant electrode corrosion. Conversely, nickel oxide and nickel-chromium oxide electrodes without phosphate anion adsorption were easily corroded. Under the same conditions, the voltage decay reached 10.4% after 350 hours of operation.

[0063] To verify the application of this passivation layer structure in the anti-oxidation and corrosion of the anode in water / seawater electrolysis, under the conditions of 1 ampere per square centimeter current density, industrial 6 moles per liter alkali concentration, 80 degrees Celsius, and saturated concentrated brine, the passivation layer structure formed in situ on the nickel-iron-vanadium-manganese dioxide / zirconium dioxide electrode could contribute to 300 hours of stable operation, verifying the important role of this multi-layer passivation layer structure formed by the combination of metal oxides and salt in the anti-oxidation and corrosion protection of the anode and the anti-oxidation and corrosion protection during cathode start-up and shutdown. Attached Figure Description

[0064] Figure 1 In-situ voltage monitoring during the passivation layer formation process in Example 1;

[0065] Figure 2 The electrode passivation layer structure of Example 1 was characterized by second-time-of-flight ion mass spectrometry.

[0066] Figure 3 The electrode micro-passivation layer structure was characterized by high-angle annular dark-field scanning transmission electron microscopy in Example 1.

[0067] Figure 4 The electrode micro-passivation layer structure was characterized by high-angle annular dark-field scanning transmission electron microscopy in Example 1.

[0068] Figure 5 The image shows the elemental distribution test image obtained using a high-angle annular dark-field scanning transmission electron microscope X-ray energy dispersive spectrometer in Example 1.

[0069] Figure 6 This is a test of the anti-wave resistance of the passivation layer in Example 1;

[0070] Figure 7 This is a test of the passivation layer's resistance to ultra-frequent fluctuations in Example 1;

[0071] Figure 8 This is a test of the corrosion resistance of the passivation layer in saturated salt water in Example 1;

[0072] Figure 9 Example 2: Testing the antioxidant and corrosion-resistant capabilities of the passivation layer in high current density, alkaline seawater;

[0073] Figure 10 Example 3: Testing the passivation layer's resistance to oxidation and dissolution in high-temperature, high-concentration alkaline electrolyte.

[0074] Figure 11 Example 4: Testing the passivation layer's resistance to oxidation, leaching, and corrosion in high temperature, high concentration alkali, and saturated brine.

[0075] Figure 12 This is a test of the oxidation resistance of the electrode without passivation layer in Comparative Example 1.

[0076] Figure 13 This is a test of the corrosion resistance of the electrode without passivation layer in Comparative Example 2. Detailed Implementation

[0077] The present invention will be described below with reference to specific embodiments, but the implementation of the present invention is not limited thereto. Experimental methods not specifically described in the embodiments generally use conventional conditions and conditions described in manuals, or conditions recommended by the manufacturer. The general equipment, materials, reagents, etc., used are all commercially available unless otherwise specified. The raw materials required in the following embodiments and comparative examples are all commercially available.

[0078] Example 1: Application of materials containing multilayer passivation layer structures in the electrolysis of water / seawater coupled with the fluctuating hydrogen evolution of renewable energy.

[0079] 1.1 Electrode Material Preparation

[0080] A three-step method was used to prepare nickel cobalt phosphide-chromium trioxide nanoarray heterojunction electrodes supported on nickel foam:

[0081] a. Add 2 mmol of nickel nitrate, 2 mmol of cobalt nitrate, and 10 mmol of urea to 36 mL of water. After ultrasonic dissolution, transfer the solution to a polytetrafluoroethylene liner and place a pretreated 2*3 cm² nickel foam sheet inside. Perform a hydrothermal reaction at 100°C for 12 hours. The resulting electrode is a nickel-cobalt hydroxide array electrode loaded on the nickel foam.

[0082] b. Place the obtained nickel-cobalt hydroxide array electrode loaded on nickel foam in a magnetic boat and place it downstream of a tube furnace. Weigh 1 gram of sodium hypophosphite and place it in another magnetic boat, place it upstream of a tube furnace, and calcine it at 400 degrees Celsius for 2.5 hours to prepare a nickel-cobalt phosphide array electrode loaded on nickel foam.

[0083] c. Using a standard two-electrode system, the prepared nickel cobalt phosphide array electrode loaded on nickel foam was used as the working electrode, and a stainless steel mesh was used as the counter electrode. 200 ml of deionized water was used to dissolve 1 mmol of chromium nitrate as the electrolyte, and electrodeposition was performed at a current density of -5 mA per square centimeter for 5 seconds. Subsequently, the resulting electrode was placed in a tube furnace and calcined at 250 degrees Celsius for 2 hours. The resulting electrode is the nickel cobalt phosphide-chromium oxide heterojunction electrode.

[0084] 1.2 Passivation layer formation process (segregation, passivation)

[0085] A standard three-electrode testing system was used. The prepared nickel-cobalt-chromium oxide heterojunction electrode was used as the working electrode for water / seawater hydrogen evolution electrolysis, the nickel foam electrode was used as the counter electrode, and the mercury / mercury oxide electrode was used as the reference electrode. Hydrogen was electrolyzed in a 1 mol / L potassium hydroxide electrolyte at a current density of 0.5 amperes per square centimeter for 12 hours, after which the current was terminated. Figure 1 As shown, a continuous rise in cathode voltage was observed after the current was terminated, up to 1.30 volts. This is a reversal phenomenon during frequent start-stop cycles. During this process, the nickel cobalt phosphide-chromium oxide electrode undergoes passivation. Cobalt oxide preferentially forms a passivation layer. As the voltage further increases, phosphorus is gradually oxidized to form a phosphate passivation layer, which, together with cobalt oxide, forms a dense oxide layer. Cobalt segregated to the surface may be further oxidized, forming an even denser metal passivation layer together with the surface chromium oxide. The superposition of the three oxide layers significantly increases the oxygen diffusion barrier, thereby terminating oxidation. Thus, a material containing a multi-layered passivation structure has been formed.

[0086] 1.3 Formation and Characterization of Passivation Layer Structure

[0087] The passivation layer structure of the electrode was characterized by in-depth analysis using second-time-of-flight ion mass spectrometry, such as... Figure 2 As shown, the results indicate that elemental segregation occurred in the nickel-cobalt phosphide-chromium oxide heterojunction electrode during oxidation. Cobalt segregated to the surface and sublayers. The surface layer also contained a small amount of loaded chromium oxide and phosphate species generated by oxidation, while the sublayer was occupied by phosphorus oxide species. The inner layer remained largely composed of zero-valent nickel active species. This suggests that at the oxidation potential, a multi-layered passivation layer structure was formed between the nickel-cobalt phosphide electrode containing nickel-cobalt-phosphorus active centers and chromium oxide. The surface layer was a composite passivation layer composed of cobalt oxide and chromium oxide, the sublayer was a phosphate layer, and the inner layer was a cobalt oxide passivation layer. This layered structure formed a dense passivation layer, significantly increasing the oxygen diffusion barrier and protecting the internal active sites from oxidation by reverse current during start-up and shutdown. Furthermore, the microstructure of the passivation layer was characterized using a high-angle annular dark-field scanning transmission electron microscope, as shown in the figure. Figure 3 As shown, a distinct three-layer passivation layer structure was observed, further validating the above conclusion. The passivation layer thickness is approximately 30-40 nanometers. In summary, Figure 3The material structure of the nickel-cobalt phosphide-chromium oxide heterojunction electrode, formed in situ during oxidation and containing a passivation layer, consists of the following layers from the inside out: an inner layer of nickel-cobalt phosphide, a cobalt oxide layer, a phosphate layer, and a composite passivation layer of chromium oxide and cobalt oxide. The composite passivation layer of chromium oxide and cobalt oxide is the surface passivation layer. The phosphate layer and the cobalt oxide layer are the intermediate passivation layers. The chromium oxide on the surface enriches the outer cobalt oxide layer, making it more dense. (This embodiment...) Figure 3 It is formed when hydrogen is evolved at a current density of 0.5 amperes per square centimeter for 12 hours, and after the hydrogen evolution reaction stops, the electrode self-discharges for 72 hours, and the discharge potential finally reaches 1.30 volts (relative to the reversible hydrogen electrode).

[0088] like Figure 4 As shown, there can be two layers: an outer phosphate layer and an inner cobalt oxide passivation layer. Different passivation layers can be formed using the same material, depending on the oxidation potential and the application time. This embodiment... Figure 4 It is formed when the electrode undergoes hydrogen evolution at a current density of 0.5 amperes per square centimeter for 12 hours, and after the hydrogen evolution reaction stops, the electrode self-discharges for 12 hours, until the oxidation potential finally reaches 1.09 volts (relative to a reversible hydrogen electrode). At this point, the passivation layer thickness is approximately 5-20 nanometers. Figure 4 The material structure containing a passivation layer formed in situ during the oxidation process of the nickel-cobalt-chromium oxide heterojunction electrode is as follows: a composite passivation layer composed of chromium oxide and phosphate coating the surface of the material, a cobalt oxide passivation layer in the middle, and nickel-cobalt phosphide active centers inside. The chromium oxide on the surface enriches the passivation layer species, making it denser and resisting oxygen tunneling.

[0089] Figure 5 For materials containing multi-layer passivation layer structures ( Figure 3 Image of elemental distribution testing using a high-angle annular dark-field scanning transmission electron microscope (X-ray energy dispersive spectroscopy) for materials. Figure 5 As can be seen, a clear passivation layer boundary can be observed.

[0090] 1.4 Resistance to fluctuations

[0091] The wave resistance of the passivation layer was evaluated using a standard two-electrode system. The prepared nickel-cobalt phosphide-chromium oxide heterojunction electrode was used as the working electrode for seawater electrolysis and hydrogen evolution, and the nickel-cobalt-iron phosphide electrode was used as the counter electrode. Wave resistance tests were conducted in a real alkaline seawater environment at a current density of 0.5 amperes per square centimeter, with a start-stop frequency of 12 hours per cycle. The results are as follows: Figure 6As shown in the figure. The results indicate that, utilizing this passivation layer structure, the nickel cobalt phosphide-chromium oxide heterojunction electrode can achieve 8000 hours of fluctuation-resistant operation in intermittent electrolytic hydrogen desorption coupled with renewable energy, with a voltage decay rate of less than 0.5% per thousand hours. This is attributed to the nickel cobalt phosphide-chromium oxide electrode preferentially forming a multilayer passivation layer structure during the reverse process, resisting excessive oxidation of the cathode by the discharge current and protecting the zero-valent active sites. Furthermore, the phosphate ions generated in situ during the oxidation process can be adsorbed on the electrode surface, resisting the corrosion and poisoning of the cathode by the abundant halide ions present in seawater.

[0092] Furthermore, while the formation of the passivation layer is crucial in the coupled renewable energy electrolysis of water / seawater cathode reverse process, the restoration of the passivation layer during hydrogen evolution is equally important, affecting whether the electrode can continuously evolve hydrogen. To test the adaptability of the passivation layer structure to ultra-frequent fluctuations, this invention conducted electrolytic hydrogen evolution in alkaline real seawater at a current density of 1 ampere per square centimeter, with ultra-frequent start-stop cycles lasting 10 minutes. The results are as follows... Figure 7 As shown. Figure 7 It is evident that the electrode containing this passivation layer structure can operate stably for 4500 hours without voltage decay under these harsh conditions. This indicates that the multilayer passivation layer generated by in-situ segregation can resist excessive cathode oxidation and chloride ion corrosion when the electrode is reversed, while simultaneously achieving reduction during the hydrogen evolution process, thus enabling long-term, high-frequency, and high-current operation with resistance to fluctuations.

[0093] 1.5 Corrosion resistance

[0094] To test the corrosion resistance of the passivation layer structure in brine, a standard two-electrode system was used. The prepared nickel-cobalt phosphide-chromium oxide heterojunction electrode was used as the working electrode for seawater hydrogen evolution electrolysis, and the nickel-cobalt-iron phosphide electrode was used as the counter electrode to evaluate the corrosion resistance of the passivation layer. Under a current density of 0.2 amperes per square centimeter, in alkaline saturated brine (electrolyte composition: 6 mol / L sodium hydroxide and 2.8 mol / L sodium chloride), the system was operated with anti-fluctuation characteristics at a frequency of 12 hours per start-stop cycle. Figure 8 As shown, the results indicate that the passivation layer structure formed in situ on the electrode can help withstand fluctuations for 450 hours, with a voltage decay of only 1.52% and no significant electrode corrosion. This demonstrates that the phosphate ions generated in situ during oxidation can be adsorbed on the electrode surface, resisting the corrosion and poisoning of the cathode by the large amount of halide ions present.

[0095] Example 2: Application of materials with multi-layer passivation layer structure in water electrolysis / seawater oxygen evolution.

[0096] 2.1 Preparation of Nickel-Iron-Manganese Silicate-Cerium Dioxide / Tantalum Pentoxide Electrode Material

[0097] A three-step method was used to prepare nickel-iron-manganese silicate-cerium dioxide / tantalum pentoxide heterojunction electrodes loaded on nickel foam.

[0098] a. Add 2 mmol nickel nitrate, 2 mmol ferric nitrate, 0.5 mmol manganese nitrate, and 10 mmol urea to 36 mL of water. After ultrasonic dissolution, transfer the solution to a polytetrafluoroethylene liner and place a pretreated 2*3 cm² nickel foam sheet inside. Perform a hydrothermal reaction at 100°C for 12 hours. The resulting electrode is a nickel-iron-manganese hydroxide array electrode supported on the nickel foam.

[0099] b. The obtained nickel-iron-manganese hydroxide array loaded on nickel foam was placed in a polytetrafluoroethylene liner of a hydrothermal reactor. 36 mL of a mixed solution of ethanol and water (ethanol to water volume ratio 1:1) was added, along with 20 mmol of nonahydrate, sodium silicate, and 10 mmol of sodium hydroxide. The prepared hydrotalcite nanoarray precursor was then placed in the reactor, and the mixture was reacted at 120 °C for 8 hours. The resulting electrode is the nickel-iron-manganese silicate nanoarray electrode.

[0100] c. Using a standard two-electrode system, the prepared nickel-iron-manganese silicate array electrode loaded on nickel foam was used as the working electrode, and a stainless steel mesh was used as the counter electrode. 200 ml of deionized water was used to dissolve 100 mmol of cerium nitrate and 20 mmol of tantalum nitrate as the electrolyte. Electrodeposition was performed at a current density of -10 mA / cm² for 10 seconds. The resulting electrode was placed in a tube furnace and calcined at 400°C for 3 hours. The resulting electrode is the cerium oxide / tantalum oxide and nickel-iron-manganese silicate nanoarray heterojunction electrode.

[0101] 2.2 The passivation layer's ability to resist oxidation and corrosion in high current density and alkaline seawater

[0102] To verify the application of the in-situ generated passivation layer structure in the oxidation and corrosion resistance of the anode in high-current-density seawater electrolysis, the nickel-iron-manganese silicate-cerium dioxide / tantalum pentoxide electrode loaded on nickel foam in Example 2 was used as the anode, and the nickel-cobalt phosphide-chromium oxide electrode prepared in Example 1 was used as the cathode. Stability tests were conducted in alkaline simulated seawater (i.e., an electrolyte solution composed of 1 mol / L sodium hydroxide and 0.5 mol / L sodium chloride) at a current density of 2 amperes per square centimeter. Figure 9 As shown, the passivation layer structure formed in situ on the nickel-iron-manganese silicate-cerium oxide / tantalum oxide electrode in Example 2 can achieve stable operation for 500 hours in alkaline simulated seawater, verifying the important role of this multi-layer passivation layer structure formed by the combination of metal oxide and salt in anodic oxidation and corrosion prevention.

[0103] The nickel-iron-manganese silicate-cerium dioxide / tantalum pentoxide electrode of this application has a material structure containing a passivation layer formed in situ during the oxidation process. From the inside out, the structure consists of: an inner layer of nickel-iron-manganese silicate, a nickel-iron silicate layer, a manganese oxide layer, and a cerium dioxide / tantalum pentoxide layer covering the surface of the material. The cerium dioxide and tantalum pentoxide on the surface enrich the passivation layer, making it more dense.

[0104] Example 3: Application of materials with multi-layer passivation layer structure in water electrolysis / seawater oxygen evolution.

[0105] 3.1 Preparation of Nickel-Iron-Chromium Silicate-Vanadium Trioxide / Niobium Pentoxide Electrode Material

[0106] A three-step method was used to prepare vanadium oxide / niobium oxide and nickel-iron-chromium silicate electrodes loaded on nickel foam.

[0107] a. Add 2 mmol nickel nitrate, 2 mmol ferric nitrate, 0.5 mmol chromium nitrate, and 10 mmol urea to 36 mL of water. After ultrasonic dissolution, transfer the solution to a polytetrafluoroethylene liner and place a pretreated 2*3 cm² nickel foam sheet inside. Perform a hydrothermal reaction at 120°C for 12 hours. The resulting electrode is a nickel-iron-chromium hydroxide array electrode supported on the nickel foam.

[0108] b. The obtained nickel-iron-chromium hydroxide array electrode loaded on nickel foam was placed in a hydrothermal reactor with a polytetrafluoroethylene liner. 36 mL of a 1:1 mixture of ethanol and water was added, along with 10 mmol of nonahydrate, sodium silicate, and 5 mmol of sodium hydroxide. The prepared hydrotalcite nanoarray precursor was then added, and the reactor was placed in the hydrothermal reactor and reacted at 160 °C for 15 hours. The resulting electrode is the nickel-iron-chromium silicate nanoarray electrode.

[0109] c. Using a standard two-electrode system, the prepared nickel-iron-chromium silicate array electrode loaded on nickel foam was used as the working electrode, and a stainless steel mesh was used as the counter electrode. 200 ml of deionized water was used to dissolve 30 mmol of vanadium nitrate and 50 mmol of niobium nitrate as the electrolyte. Electrodeposition was performed at a current density of -100 mA / cm² for 1800 seconds. The resulting electrode was placed in a tube furnace and calcined at 250°C for 3 hours. The resulting electrode is the nickel-iron-chromium silicate-vanadium trioxide / niobium pentoxide electrode.

[0110] 3.2 Antioxidant and anti-dissolution capabilities of the passivation layer in high-temperature, high-concentration alkaline electrolytes

[0111] To test the resistance to leaching and oxidation of the in-situ generated passivation layer structure during high-temperature, high-concentration alkaline water electrolysis, a nickel-iron-chromium silicate-vanadium trioxide / niobium pentoxide electrode prepared in Example 3 with a working area of ​​1*1 square centimeters was used as the anode, and a nickel-cobalt-iron phosphide-chromium oxide heterojunction electrode prepared in Example 1 with a working area of ​​1*1 square centimeters was used as the cathode. The electrolyte was a 6 mol / L sodium hydroxide solution, and a constant current test was conducted at 80 degrees Celsius and a current density of 1 A / cm².

[0112] The results are as follows Figure 10 As shown, the nickel-iron-chromium silicate-vanadium trioxide / niobium pentoxide electrode prepared in Example 3 can operate stably for 500 hours under industrial high-temperature and high-alkali concentration conditions. This is attributed to the fact that during the oxygen evolution process, the electrode can be reconstructed into a multi-layer passivation layer structure consisting of a vanadium trioxide / niobium pentoxide anti-oxidation layer on the surface and chromium oxide and nickel-iron silicate on the inside, resisting excessive oxidation of nickel and iron at the active sites under high current and inhibiting dissolution of the active sites. Furthermore, the silicate ions generated in situ during the oxidation process can be adsorbed on the electrode surface to form an anion hydration layer, maintaining local hydroxyl enrichment on the electrode surface and preventing the decrease in electrode stability caused by excessive consumption of hydroxyl ions under high current density.

[0113] The material structure containing a passivation layer formed in situ during the oxidation process of the nickel-iron-chromium silicate-vanadium trioxide / niobium pentoxide electrode of this application consists of the following layers from the inside out: nickel-iron-chromium silicate located inside, nickel-iron silicate layer, chromium oxide layer, and vanadium trioxide and niobium pentoxide layers covering the surface of the material.

[0114] Example 4: Application of materials with multi-layer passivation layer structure in water electrolysis / seawater oxygen evolution.

[0115] 4.1 Preparation of nickel-iron-vanadium sulfide-manganese dioxide / zirconium dioxide heterojunction electrode

[0116] A three-step method was used to prepare nickel-iron-vanadium-manganese dioxide / zirconium dioxide heterojunction electrodes loaded on nickel foam.

[0117] a. Add 2 mmol nickel nitrate, 2 mmol ferric nitrate, 1 mmol vanadium nitrate, and 10 mmol urea to 36 mL of water. After ultrasonic dissolution, transfer the solution to a polytetrafluoroethylene liner and place a pretreated 2*3 cm² nickel foam sheet inside. Perform a hydrothermal reaction at 120°C for 12 hours. The resulting electrode is a nickel-iron-vanadium hydroxide array electrode supported on the nickel foam.

[0118] b. The obtained nickel-iron-vanadium hydroxide array electrode loaded on nickel foam was placed in a polytetrafluoroethylene liner of a hydrothermal autoclave, and 30 mL of ethanol and 0.5 g of thiourea were added. The electrode was prepared by hydrothermal treatment at 140 °C for 12 hours to prepare a nickel-iron-vanadium sulfide array electrode loaded on nickel foam.

[0119] c. Using a standard two-electrode system, the prepared nickel-iron-vanadium sulfide array electrode loaded on nickel foam was used as the working electrode, and a stainless steel mesh was used as the counter electrode. 200 ml of deionized water was used to dissolve 30 mmol of manganese nitrate and 70 mmol of zirconium nitrate as the electrolyte. Electrodeposition was performed at a current density of -1 mA per square centimeter for 3600 seconds. The resulting electrode was placed in a tube furnace and calcined at 300 degrees Celsius for 3 hours. The resulting electrode is a heterojunction electrode of manganese dioxide / zirconium dioxide and nickel-iron-vanadium sulfide.

[0120] 4.2 The passivation layer's resistance to oxidation, leaching, and corrosion in high-temperature, high-concentration alkali, and saturated brine conditions.

[0121] To test the antioxidant, anti-dissolution, and anti-corrosion capabilities of the in-situ generated multilayer passivation layer structure in high temperature, high concentration alkali, and saturated brine, the nickel-iron-vanadium sulfide-manganese dioxide / zirconium dioxide heterojunction electrode of Example 4 with a working area of ​​1*1 square centimeters was used as the anode, and the nickel-cobalt-iron phosphide-chromium oxide heterojunction electrode of Example 1 with a working area of ​​1*1 square centimeters was used as the cathode. The electrolyte consisted of 6 mol / L sodium hydroxide and 2.8 mol / L sodium chloride. A constant current test was performed at 80 degrees Celsius and a current density of 1 amp / cm². The results are as follows: Figure 11 As shown.

[0122] Figure 11 As can be seen, the nickel-iron-vanadium-sulfide-manganese dioxide / zirconium dioxide heterojunction electrode of Example 4 can operate stably for 300 hours without significant voltage decay in industrial high-temperature, high-concentration alkali, and saturated concentrated brine environments. This is attributed to the formation of a dense, multi-layered passivation layer structure composed of manganese oxide / zirconium oxide-vanadium oxide-nickel-iron sulfate in situ during the oxidation process, which resists oxygen tunneling and prevents excessive oxidation of the electrode under high-temperature, high-concentration alkali conditions. Simultaneously, the phosphate ions generated in situ can be adsorbed on the electrode surface, effectively resisting chloride ion corrosion of the electrode substrate.

[0123] The material structure of the nickel-iron-vanadium sulfide-manganese dioxide / zirconium dioxide heterojunction electrode of this application, which forms in situ during the oxidation process and contains a passivation layer, consists of the following layers from the inside out: nickel-iron-vanadium sulfide layer, nickel-iron sulfate layer, vanadium oxide layer, and manganese dioxide and zirconium dioxide layers covering the surface of the material. The manganese dioxide and zirconium oxide layers on the surface serve to enrich the outermost passivation layer.

[0124] Comparative Example 1: Oxidation resistance of electrode without passivation layer

[0125] A nickel-cobalt bilayer hydroxide array electrode supported on nickel foam was prepared using the steps of Example 1a. The nickel-cobalt bilayer hydroxide array electrode was used as the cathode, and a nickel-cobalt-iron phosphide electrode was used as the anode. The electrode's resistance to fluctuations was evaluated using a standard two-electrode system. Figure 12 As shown, because the cathode electrode, the nickel-cobalt double-layer hydroxide array electrode, lacks non-metallic phosphorus doping and a chromium oxide heterojunction structure, it cannot form a dense passivation layer structure composed of metal oxides and phosphates. The nickel-cobalt layered double hydroxide electrode is easily oxidized during frequent start-up and shutdown. Under a current density of 0.5 amperes per square centimeter in an alkaline real seawater environment, the voltage decay rate reaches 20.58% after 800 hours of operation at a frequency of 12 hours per start-up and shutdown. This indicates that the nickel-cobalt layered double hydroxide electrode, without the phosphate combination to form a dense passivation layer, cannot continuously resist oxidation during the reverse process, resulting in the deactivation of active sites and voltage decay.

[0126] Comparative Example 2: Corrosion resistance of electrodes without passivation layer

[0127] Nickel-nickel oxide-chromium oxide heterojunction electrodes were prepared using a two-step method:

[0128] 150 mL of solutions containing 5 mmol and 0.6 mmol of Ni(NO3)2 and Cr(NO3)3 were prepared. Nickel foam was used as the working electrode, stainless steel mesh as the counter electrode, and a saturated calomel electrode as the reference electrode. Electrodeposition was performed at -1.2 V until the charge reached 50 coulombs per square centimeter. The nickel foam was rinsed with deionized water and dried, then transferred to a vacuum tube furnace and calcined at 300°C for 1 hour under a 1.5% hydrogen atmosphere. The resulting electrode was a nickel-nickel oxide-chromium oxide heteroelectrode.

[0129] A nickel-nickel oxide-chromium oxide heterojunction electrode was used as the cathode, and a nickel-cobalt-iron phosphide electrode was used as the anode. The corrosion resistance of the nickel-nickel oxide-chromium oxide heterojunction electrode was evaluated using a standard two-electrode system. The results showed that the nickel-nickel oxide-chromium oxide heterojunction electrode could not generate phosphate anions during the reverse process, nor could it form a multilayer passivation layer composed of metal oxide and salt. Therefore, the nickel-nickel oxide-chromium oxide electrode was easily corroded by the large amount of halide ions present in the electrolyte. Under a current density of 0.2 amperes per square centimeter in alkaline saturated brine, with a start-stop frequency of 12 hours per cycle, the voltage decay reached 10.4% after 350 hours of operation.

[0130] From the above analysis, it can be concluded that the multi-layer passivation layer structure can be applied to the oxidation and corrosion prevention of oxygen evolution at the anode of water / seawater electrolysis and the oxidation and corrosion prevention of hydrogen evolution coupled with fluctuating renewable energy in water / seawater electrolysis. The oxidation resistance is attributed to the effective prevention of oxygen tunneling by the dense, multi-layered passivation layer structure formed by in-situ segregation. Therefore, two, three, four, and multiple passivation layers are all applicable. The corrosion resistance is attributed to the adsorption of in-situ generated acid radicals on the electrode surface, effectively resisting corrosion from the abundant halide ions present in seawater. Therefore, replacing the salt with phosphates, sulfates, or silicates is also applicable. The order of metal oxide layer and salt formation in the passivation layer is attributed to the oxidation potential. Depending on the different oxidation potentials of the metal and non-metal anionic salts, the order of passivation layer formation differs. When the metal oxidation potential is lower than that of the non-metal anionic salt, the metal oxide layer is preferentially formed, followed by the non-metal anionic salt oxide layer. In Example 1, this is manifested as the formation of a cobalt oxide passivation layer first, followed by a phosphate passivation layer. When the oxidation potential of a non-metallic anionic salt is lower than that of a metal, a non-metallic anionic salt oxide layer is preferentially formed, followed by the formation of a metal oxide layer. In Example 2, this is manifested as the formation of a sulfate passivation layer first, followed by the formation of a manganese oxide passivation layer. The essence of the passivation layer's antioxidant properties is that the two layers stack together to form a dense passivation layer, resisting oxygen tunneling. Therefore, the combination sequence of the metal oxide layer and the salt, such as metal oxide layer-salt-metal oxide layer, salt-metal oxide layer, metal oxide layer-salt, and any combination thereof, is equally applicable. The metal oxide being one or more of cobalt oxide, manganese oxide, chromium oxide, etc., is also applicable. Furthermore, coating the passivation layer with one or more high-oxidation-potential species such as chromium oxide, manganese oxide, zirconium oxide, cerium oxide, niobium oxide, tantalum oxide, etc., can further enrich the oxygen species abundance of the outermost passivation layer; coating with zero or one or more high-oxidation-potential species is also applicable.

Claims

1. A material containing a passivation layer structure, characterized in that, The material includes: a metal phosphide / metal sulfide / metal silicate located inside, a surface passivation layer covering the surface of the material, and an intermediate passivation layer between the metal phosphide / metal sulfide / metal silicate and the metal oxide; The surface passivation layer is a first metal oxide layer or a composite passivation layer; The intermediate passivation layer is selected from one or more layers of: a second metal oxide layer and a non-metal anion salt layer; The composite passivation layer is: a mixed layer containing a first metal oxide and a second metal oxide, a mixed layer containing a first metal oxide and a non-metal anionic salt, or a mixed layer containing a first metal oxide, a non-metal anionic salt and a second metal oxide. The metal phosphide / metal sulfide / metal silicate is a metal phosphide, metal sulfide, or metal silicate.

2. The material containing a passivation layer structure according to claim 1, characterized in that, The metal in the metal phosphide / metal sulfide / metal silicate is selected from one or more of the following: nickel, cobalt, iron, vanadium, chromium, and manganese; The first metal oxide is selected from one or more of the following: chromium oxide, manganese oxide, zirconium oxide, cerium oxide, niobium oxide, tantalum oxide, and vanadium oxide; the metal in the first metal oxide is in a valence state of +3 or higher.

3. The material containing a passivation layer structure according to claim 1, characterized in that, The first metal oxide is selected from one or more of the following: chromium trioxide, manganese dioxide, zirconium dioxide, cerium dioxide, niobium pentoxide, tantalum pentoxide, and vanadium pentoxide.

4. The material containing a passivation layer structure according to claim 1, characterized in that, The non-metallic anionic salt layer is selected from one or more of the following: sulfate, phosphate, and silicate layers; The second metal oxide layer is selected from one or more of the following: vanadium oxide layer, nickel oxide layer, cobalt oxide layer, chromium oxide layer, manganese oxide layer, and iron oxide layer.

5. The material containing a passivation layer structure according to claim 1, characterized in that, The metal in the second metal oxide layer is selected from the metal phosphide / metal sulfide / metal silicate; When the material includes the metal phosphide, the non-metallic anionic salt layer includes a phosphate layer; When the material includes the metal sulfide, the nonmetallic anionic salt layer includes a sulfate layer; When the material includes the metal silicate, the non-metallic anionic salt layer includes a silicate layer.

6. The material containing a passivation layer structure according to claim 1, characterized in that, The total thickness of the surface passivation layer and the intermediate passivation layer is 5–40 nanometers.

7. A method for preparing a material containing a passivation layer structure, characterized in that, The preparation method includes the following steps: Step A: Provide heterojunction materials; The heterojunction material comprises: a metal phosphide / metal sulfide / metal silicate and a metal oxide nanoarray; the metal phosphide / metal sulfide / metal silicate and the metal oxide form a heterojunction; The metal phosphide / metal sulfide / metal silicate is a metal phosphide, a metal sulfide, or a metal silicate; Step B: Using the heterojunction material as the cathode for electrolysis of water / seawater under frequent start-stop conditions, or using the heterojunction material as the anode for electrolysis of water / seawater under oxidation potential, the material described in claim 1 is obtained.

8. The application of the material containing the passivation layer structure as described in claim 1 in water electrolysis / seawater oxygen evolution.

9. The application of the material containing the passivation layer structure as described in claim 1 in hydrogen evolution of electrolyzed water / seawater coupled with wave energy.

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