An Fe 1.7 Ni 1.43 Atmosphere-controlled synthesis method of FeO4-defective electrocatalyst and its bifunctional application

Abstract

The application relates to a Fe 1.7 Ni 1.43 O4 defect type electrocatalyst, and belongs to the technical field of electrocatalyst materials. The synthesis method comprises the following steps: washing and drying a conductive substrate for standby; dissolving an iron source, a nickel source, a morphology regulating agent and a precipitant in a solvent to form a uniform precursor solution; immersing the conductive substrate in the precursor solution and heating to react; taking out, washing and drying the conductive substrate to obtain a substrate loaded with the precursor; placing the substrate in a controllable atmosphere for heat treatment; and obtaining the Fe 1.7 Ni 1.43 O4 defect type electrocatalyst grown on the substrate by regulating the cooling mode. The application solves the technical problems of insufficient intrinsic catalytic activity, poor conductivity, unbalanced dual-function catalytic activity and difficult precise control in the synthesis process of traditional iron-nickel oxides, and simultaneously improves the dual-function catalytic performance of oxygen evolution and hydrogen evolution in the electrocatalytic water splitting reaction.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalyst materials technology, specifically relating to a Fe... 1.7 Ni 1.43 Atmosphere-controlled synthesis method of O4 defective electrocatalyst and its bifunctional application. Background Technology

[0002] Electrolysis of water is a crucial pathway for producing green hydrogen. However, the overall energy conversion efficiency of this technology is limited by the slow kinetics of two half-reactions: the oxygen evolution reaction (OER) at the anolyte and the hydrogen evolution reaction (HER) at the cathodicly. Currently, high-performance electrocatalysts heavily rely on noble metals such as platinum (Pt), iridium (Ir), and ruthenium (Ru) and their oxides. While these materials possess excellent catalytic activity, their high cost and scarce natural resource reserves significantly restrict the large-scale commercial application of water electrolysis technology. Therefore, developing low-cost, highly active non-noble metal-based electrocatalysts has become a key research focus and an inevitable trend in this field.

[0003] Among numerous candidate materials, transition metals such as iron (Fe), nickel (Ni), and cobalt (Co) and their oxides have attracted widespread attention due to their abundant reserves and low prices. Among these, iron-nickel composite oxides with a spinel structure (such as NiFe₂O₄) exhibit good (electro)chemical stability and potential OER catalytic activity in alkaline media. However, traditional stoichiometric spinel iron-nickel oxides still face several fundamental challenges that limit their practical applications: First, their intrinsic catalytic activity is limited; their defined crystal structure and cation occupancy (such as Fe) are also limited. 3+ Occupying an octagonal position, Ni 2+ The occupancy of tetrahedral sites results in a narrow range of tunable electronic structure, making it difficult to optimize the adsorption energy for OER or HER reaction intermediates to the best value, thus limiting intrinsic activity. Secondly, poor conductivity; most transition metal oxides exhibit semiconductor properties, with high charge transport resistance, hindering rapid electron transfer during the reaction and affecting reaction kinetics. Furthermore, an imbalance in bifunctional catalytic activity; while traditional iron-nickel oxides show some potential in OER, their HER activity is typically weak, making it difficult to achieve efficient and stable full water splitting on the same material. Separately preparing and integrating two high-performance monofunctional catalysts increases process complexity and interfacial impedance.

[0004] To overcome these bottlenecks, defect engineering is considered an effective strategy. Research in materials science has confirmed that by precisely controlling the non-stoichiometry of transition metal oxides, controllable cation vacancies, anion vacancies (such as oxygen vacancies), and mixed valence states (such as Fe) can be introduced. 2+ / Fe 3+ Ni 2+ / Ni3+ (Coexistence) can effectively modulate its electronic structure, Fermi level, and charge transport properties, while creating a large number of unsaturated coordination sites as highly active centers. For example, both theoretical calculations and experiments suggest that in A x B 3-x In O4 type spinel, a specific Fe / Ni ratio that deviates from the standard stoichiometry (e.g., Fe...) 1.7 Ni 1.43 O4 may be accompanied by optimized cation distribution and defect concentration, thereby synergistically enhancing the adsorption / desorption behavior of key intermediates of OER and HER, achieving a joint enhancement of bifunctional activity.

[0005] However, translating this theoretical concept into a practically usable catalyst remains a significant challenge. Existing synthetic methods largely focus on preparing stoichiometric materials or can only roughly introduce defects, making it difficult to achieve the desired results for non-stoichiometric compositions (such as Fe). 1.7 Ni 1.43 While the precise and controllable synthesis of O4 is possible, it is even more difficult to finely regulate the type, concentration, and spatial distribution of defects. Furthermore, many methods are complex and demanding, and it is difficult to directly and firmly grow active materials with specific defect structures on conductive substrates to construct self-supporting electrodes without binders, which is crucial for ensuring excellent electronic conduction, mechanical stability, and ease of practical application.

[0006] Therefore, developing a relatively simple and controllable synthesis method that can accurately prepare iron-nickel oxides with well-defined non-integral compositions and abundant defect structures, and integrating them onto a three-dimensional conductive framework to form a high-performance bifunctional self-supporting electrode, is of great scientific significance and application value for promoting the development of low-cost and efficient water electrolysis hydrogen production technology. Summary of the Invention

[0007] The purpose of this invention is to provide a Fe 1.7 Ni 1.43 The aim of this study is to synthesize O4 defective electrocatalysts under controlled atmosphere and to achieve precise control over non-integral composition and defect structure through a controlled atmosphere pyrolysis process, thereby obtaining highly efficient and stable OER / HER bifunctional electrocatalytic activity.

[0008] On the one hand, the present invention provides a Fe 1.7 Ni 1.43 The atmosphere-controlled synthesis method for O4-defective electrocatalysts employs the following technical solution: A Fe 1.7 Ni 1.43 An atmosphere-controlled synthesis method for O4-defective electrocatalysts includes the following steps: 1) Clean and dry the conductive substrate for later use; 2) Dissolve the iron source, nickel source, morphology modifier and precipitant in a solvent to form a homogeneous precursor solution; 3) Immerse the conductive substrate treated in step 1) into the precursor solution prepared in step 2), heat and react, remove the conductive substrate, clean and dry it to obtain a substrate loaded with the precursor. 4) The substrate treated in step 3) is placed in a controlled atmosphere for heat treatment, and then Fe is grown on the substrate by controlling the cooling method. 1.7 Ni 1.43 O4 defective electrocatalyst.

[0009] Preferably, in step 4), the controllable atmosphere is an inert gas, air, or an O2 / N2 mixed atmosphere with controllable oxygen partial pressure; In step 4), the controllable atmosphere is an O2 / N2 mixed atmosphere with controllable oxygen partial pressure, wherein the volume fraction of O2 is 1-20%.

[0010] Preferably, in step 4), the heat treatment is to hold at 300-600℃ for 1-6 hours, with a heating rate of 2-10℃ / min.

[0011] Preferably, in step 4), the cooling method is any one of rapid quenching, controlled-speed cooling, or atmosphere switching cooling.

[0012] Preferably, in step 2), the iron source is ferric nitrate and the nickel source is nickel acetate; The molar ratio of the iron source to the nickel source is 1.2:1.

[0013] Preferably, in step 2), the morphology control agent is ammonium fluoride; The precipitant is urea.

[0014] Preferably, in step 3), the heating reaction is either a hydrothermal reaction or a solvothermal reaction; The heating reaction is carried out at a temperature of 150-200℃ for 2-12 hours.

[0015] Preferably, in step 1), the conductive substrate is nickel foam.

[0016] On the one hand, the present invention also provides a method using Fe 1.7 Ni 1.43 O4 defective electrocatalyst.

[0017] A Fe 1.7 Ni 1.43 The O4 defective electrocatalyst was prepared by the above-described synthesis method. The electrocatalyst is a self-supporting heterojunction material grown on a three-dimensional porous conductive substrate, and has a nanosheet array morphology and a defect structure with cation vacancies and mixed valence states.

[0018] Furthermore, the present invention also provides Fe 1.7 Ni 1.43 Application of O4 defective electrocatalysts in electrochemical water splitting reactions.

[0019] A Fe as described above 1.7 Ni 1.43 Application of O4-deficient electrocatalysts in electrochemical water splitting reactions, wherein the electrocatalyst serves as the working electrode for catalyzing oxygen evolution reaction and / or hydrogen evolution reaction.

[0020] In summary, the present invention has the following beneficial technical effects: 1. This invention achieves Fe through a synergistic strategy of precursor design, hydrothermal synthesis, and atmosphere-controlled pyrolysis. 1.7 Ni 1.43 The precise control of specific non-stoichiometric ratios and defect structures such as cation vacancies and mixed valence states in O4 has solved the bottleneck of existing technologies that make it difficult to accurately control non-integer ratios and defect distribution.

[0021] 2. The active material of this invention is directly grown on a three-dimensional porous nickel foam substrate to form a nanosheet array structure without the need for a binder, ensuring excellent electronic conductivity, abundant exposure of active sites and good structural stability. The resulting catalyst exhibits high activity and low overpotential for both oxygen evolution reaction and hydrogen evolution reaction, achieving efficient and stable full water splitting catalysis, and providing a new strategy for the design of non-precious metal bifunctional catalysts. Attached Figure Description

[0022] Figure 1 Fe prepared in Example 1 1.7 Ni 1.43 X-ray diffraction pattern of O4 catalyst; Figure 2 The X-ray diffraction pattern of the Fe2NiO4 catalyst prepared in Comparative Example 3 is shown. Figure 3 Fe prepared in Example 1 1.7 Ni 1.43 Scanning electron microscope image of O4 catalyst; Figure 4 Fe prepared in Example 1 1.7 Ni 1.43 OER polarization curves of O4 catalyst and comparative samples NiO and Fe3O4 in 1.0M KOH; Figure 5 Fe prepared in Examples 1-3 1.7 Ni 1.43 OER polarization curve of O4 catalyst in 1.0M KOH; Figure 6 The OER polarization curves of the catalysts prepared in Example 1 and Comparative Example 3 in 1.0 M KOH are shown. Figure 7 Fe prepared in Example 1 1.7 Ni 1.43 HER polarization curves of O4 catalyst and comparative samples NiO and Fe3O4 in 1.0 M KOH; Figure 8 Fe prepared in Examples 1-3 1.7 Ni 1.43 HER polarization curve of O4 catalyst in 1.0M KOH; Figure 9 The HER polarization curves of the catalysts prepared in Example 1 and Comparative Example 3 in 1.0 M KOH are shown. Detailed Implementation

[0023] The following description is based on Examples 1-3, comparative examples, and the appendix to the instruction manual. Figure 1-9 The present invention will be described in further detail below.

[0024] Example Example 1 A Fe 1.7 Ni 1.43 An atmosphere-controlled synthesis method for O4-defective electrocatalysts includes the following steps: S1. Cut the nickel foam into 2cm*1cm pieces, and ultrasonically clean them for 15min each in anhydrous ethanol, 3.0M hydrochloric acid, and deionized water. Then vacuum dry them at 60℃ for 12h for later use. S2. Weigh 0.4805g of urea and 0.1482g of ammonium fluoride, dissolve them in 15mL of deionized water to obtain a mixed solution; According to the molar ratio of total metal ions (Fe+Ni) to urea and ammonium fluoride being 1:4:2, and the Fe:Ni molar ratio being 1.2:1, approximately 0.4408 g of ferric nitrate nonahydrate (Fe(NO3)3·9H2O) and approximately 0.2262 g of nickel acetate tetrahydrate (Ni(CH3COO)2·4H2O) were weighed and added to the mixed solution, and stirred until completely dissolved to obtain a homogeneous precursor solution; S3. The foamed nickel treated in step S1 is vertically immersed into a reaction vessel containing 15 mL of the precursor solution prepared in step S2. After sealing, it is placed in a forced-air drying oven, heated to 180°C and maintained for 2 hours. After naturally cooling to room temperature, the foamed nickel is removed, rinsed several times with deionized water, and dried at 80°C to obtain a substrate loaded with the precursor. S4. Place the substrate treated in step S3 into a controlled atmosphere tube furnace. First, introduce N2 gas to purge the air, then switch to an O2 / N2 mixture (O2 volume fraction 5%). Heat to 400℃ at 5℃ / min and hold for 2 hours. After holding, quickly push the substrate into the furnace cooling zone and quench it to room temperature in an N2 gas flow to obtain Fe grown on nickel foam. 1.7 Ni 1.43 O4 catalyst (denoted as Fe) 1.7 Ni 1.43 O4-400-5%O2).

[0025] Example 2 A Fe 1.7 Ni 1.43 The atmosphere-controlled synthesis method for O4-defective electrocatalysts differs from Example 1 in that, in step S3, the temperature is raised to 150°C and maintained for 2 hours; the remaining steps are identical to those in Example 1, yielding Fe grown on nickel foam. 1.7 Ni 1.43 O4 catalyst (denoted as Fe) 1.7 Ni 1.43 O4-150).

[0026] Example 3 A Fe 1.7 Ni 1.43 The atmosphere-controlled synthesis method for O4-defective electrocatalysts differs from Example 1 in that, in step S3, the temperature is raised to 200°C and maintained for 2 hours; the remaining steps are identical to those in Example 1, yielding Fe grown on nickel foam. 1.7 Ni 1.43 O4 catalyst (denoted as Fe) 1.7 Ni 1.43 O4-200).

[0027] Comparative Example Comparative Example 1 A method for synthesizing a catalyst, which differs from Example 1, is as follows: in S2, ferric nitrate is not added, and only nickel acetate is used as the nickel source; in S4, the calcination atmosphere is air; and the remaining steps are the same as in Example 1, to obtain a pure Ni-based catalyst (denoted as Ni-180).

[0028] Comparative Example 2 A method for synthesizing a catalyst, which differs from Example 1, is as follows: in S2, nickel acetate is not added, and only ferric nitrate is used as the iron source; in S4, the calcination atmosphere is air; and the remaining steps are the same as in Example 1, to obtain a pure Fe-based catalyst (denoted as Fe-180).

[0029] Comparative Example 3 A method for synthesizing a catalyst, comprising the following steps: S1. Cut the nickel foam into 2cm*1cm pieces, and ultrasonically clean them for 15min each in anhydrous ethanol, 3.0M hydrochloric acid, and deionized water. Then vacuum dry them at 60℃ for 12h for later use. S2. Weigh 0.4805g of urea and 0.1482g of ammonium fluoride, dissolve them in 15mL of deionized water to obtain a mixed solution; According to the Fe:Ni molar ratio of 2:1, ferric nitrate and nickel acetate were weighed and added to the mixed solution, and stirred until completely dissolved to obtain a homogeneous precursor solution; S3. The foamed nickel treated in step S1 is vertically immersed into a reaction vessel containing 15 mL of the precursor solution prepared in step S2. After sealing, it is placed in a forced-air drying oven, heated to 180°C and maintained for 2 hours. After naturally cooling to room temperature, the foamed nickel is removed, rinsed several times with deionized water, and dried at 80°C to obtain a substrate loaded with the precursor. S4. The substrate treated in step S3 is placed in a controlled atmosphere tube furnace. First, N2 gas is introduced to purge the air, and then the atmosphere is switched to air. The temperature is increased to 400℃ at 5℃ / min and held for 4h. After the holding period, the substrate is naturally cooled to room temperature to obtain the Fe2NiO4 catalyst.

[0030] Test case Test Example 1 X-ray diffraction tests were performed on the catalysts prepared in Example 1 and Comparative Example 3.

[0031] Reference Figure 1 Fe prepared in Example 1 1.7 Ni 1.43 The O4 catalyst exhibited distinct diffraction peaks at 31°, 36°, 37°, 42°, 58°, and 62°, corresponding to Fe, respectively. 1.7 Ni 1.43 The (220), (222), (400), (511), and (440) crystal planes of O4 are basically consistent with the standard PDF card (PDF#80-0072), indicating that Fe without impurities has been successfully prepared. 1.7 Ni 1.43 O4 catalyst.

[0032] Reference Figure 2 The Fe2NiO4 catalyst prepared in Comparative Example 3 showed obvious diffraction peaks at positions of 30.1°, 35.4°, 37.1°, 43.1°, 57.0°, and 62.6°, which correspond to the (220), (311), (222), (400), (511), and (440) crystal planes of the spinel structure, respectively. These peaks were highly consistent with the standard PDF card (PDF#10-0325, Fe2NiO4), indicating that a well-crystallized stoichiometric Fe2NiO4 spinel phase was successfully synthesized.

[0033] Reference Figure 1 and Figure 2 Fe prepared in Example 1 1.7 Ni 1.43 The intensity ratio of the (440) diffraction peak of the O4 catalyst to its (311) main peak is significantly higher than that of the corresponding ratio in Fe2NiO4 prepared in Comparative Example 3. The intensity ratio of the (440) peak to its (311) main peak of the Fe2NiO4 catalyst is significantly lower than that of Fe... 1.7 Ni 1.43 The situation in the O4 catalyst. In Fe... 1.7 Ni 1.43 In the O4 catalyst, the intensity ratio of the (440) crystal plane diffraction peak to the (311) main peak is significantly higher than that of the standard Fe2NiO4 catalyst, which directly reflects the significant difference in its cation distribution. Due to the nickel-rich composition, excess Ni... 2+ The ionic portion occupied the space originally occupied by Fe 3+ Dominant tetrahedral interstitial site (A-site). Ni 2+ The stronger atomic scattering factor directly enhances the scattering contribution of the A-site to X-rays. More importantly, this occupancy change alters the relative phase of the scattered waves from the A-site and B-site (octahedral interstitial) atoms, resulting in more favorable constructive interference in the specific diffraction direction (440). Therefore, the structure factor of the (440) peak is selectively enhanced, leading to a significant increase in its relative intensity. This phenomenon provides direct XRD evidence for the cation rearrangement in the spinel structure caused by non-stoichiometric composition.

[0034] Reference Figure 1 and Figure 2 Fe prepared in Example 1 1.7 Ni 1.43 The diffraction peaks of the O4 catalyst all showed a slight shift towards lower angles compared to the Fe2NiO4 prepared in Comparative Example 3, indicating a slight increase in its lattice constant. This may be due to the Ni... 2 + (0.069nm) partially replaces Fe 3+ The entry of (0.0645nm) into the A site, along with the introduction of oxygen vacancies, together lead to lattice expansion.

[0035] Test Example 2 The catalyst prepared in Example 1 was subjected to X-ray diffraction testing.

[0036] Reference Figure 3 Fe prepared in Example 1 1.7 Ni 1.43O4 catalyst is uniformly grown on the surface of a nickel foam substrate, forming a continuous three-dimensional porous network framework. This structure has abundant pores and open channels, which is beneficial for electrolyte penetration and ion transport. 1.7 Ni 1.43 The active material of the O4 catalyst exhibits a vertically grown nanosheet array structure, with nanosheets approximately 20-50 nm thick. The interconnected nanosheets form open, layered spaces, effectively increasing the specific surface area and exposing more active sites. The nanosheets uniformly cover the surface of the nickel foam framework, with no obvious agglomeration or detachment observed, indicating a good interfacial bond between the hydrothermal growth of the precursor and the subsequent pyrolysis process, which is beneficial for electron conduction and structural stability.

[0037] Test Example 3 The OER performance of the catalyst was tested in a standard three-electrode system. A self-supporting electrode (1×1 cm⁻¹) was used. 2 The electrode is a Pt sheet as the counter electrode, and Ag / AgCl is the reference electrode. The electrolyte is 1.0 M KOH. All potentials are converted relative to the reversible hydrogen electrode (RHE).

[0038] Reference Figure 4 , Figure 4 The OER polarization curves are shown for the catalysts prepared in Example 1, Comparative Example 1, and Comparative Example 2. The Fe catalyst prepared in Example 1... 1.7 Ni 1.43 O4 catalyst at a current density of 10 mA cm⁻¹ -2 It exhibits the lowest overpotential, indicating that it has optimal OER activity.

[0039] Reference Figure 5 , Figure 5 The OER polarization curves of the catalysts prepared in Examples 1-3 are shown. The Fe catalyst prepared in Example 1 was subjected to hydrothermal treatment at 180°C. 1.7 Ni 1.43 The O4 catalyst exhibits the highest activity.

[0040] Reference Figure 6 , Figure 6 The OER polarization curves are shown for the catalysts prepared in Example 1 and Comparative Example 3. The Fe catalyst prepared in Example 1... 1.7 Ni 1.43 The O4 catalyst exhibits a low overpotential, indicating that the non-integer preparation method has higher activity.

[0041] Test Example 4 The HER performance of the catalyst was evaluated under the same test conditions.

[0042] Reference Figure 7 , Figure 7The image shows the HER polarization curves of the catalyst prepared in Example 1 and the comparative samples NiO and Fe3O4. When the potential is near -0.4V (vs. RHE), the Fe3O4 prepared in Example 1... 1.7 Ni 1.43 The absolute value of the current density of the O4 catalyst is significantly greater than that of NiO and Fe3O4, indicating that its hydrogen evolution reaction rate is faster at the same potential. As the potential shifts towards "0V" (the more favorable low overpotential region) (e.g., around -0.2V), Fe... 1.7 Ni 1.43 The current density of the O4 catalyst remained at a high level, while the current density of the comparison samples NiO and Fe3O4 decreased more significantly, which reflects the fact that Fe... 1.7 Ni 1.43 The HER catalytic activity of O4 catalyst is far superior to that of NiO and Fe3O4 alone.

[0043] Reference Figure 8 , Figure 8 The image shows the HER polarization curves of the catalysts prepared in Examples 1-3. When the potential is near -0.3V (vs. RHE), the Fe catalyst prepared in Example 1... 1.7 Ni 1.43 The O4 catalyst has the highest absolute current density, and the Fe prepared in Example 3... 1.7 Ni 1.43 The absolute value of the current density of the O4 catalyst is relatively small. As the potential shifts towards "0V", the Fe prepared in Example 1... 1.7 Ni 1.43 The O4 catalyst maintained a high current density, demonstrating superior HER catalytic activity. By comparing the HER activity of the catalyst at different hydrothermal temperatures, the regulatory effect of hydrothermal temperature on the catalyst morphology / structure can be clearly identified.

[0044] Reference Figure 9 , Figure 9 The HER polarization curves are shown for the catalysts prepared in Example 1 and Comparative Example 3. The non-stoichiometric Fe of this invention... 1.7 Ni 1.43 The HER activity of O4 catalyst in the low overpotential region is significantly better than that of Fe2NiO4 with conventional stoichiometry.

[0045] The embodiments shown in this specification are only used to illustrate the technical solutions of the present invention and are intended to help those skilled in the art understand the principles and advantages of the present invention. They do not constitute a limitation on the scope of protection of the present invention. Although the present invention has been specifically described, those skilled in the art can still make any modifications, equivalent substitutions or other reasonable variations to the implementation methods without departing from the spirit and scope of the present invention. All equivalent technical solutions resulting therefrom should be considered within the scope of protection of this patent.

Claims

1. A Fe 1.7 Ni 1.43 An atmosphere-controlled synthesis method for O4-deficient electrocatalysts, characterized in that... Includes the following steps: 1) Clean and dry the conductive substrate for later use; 2) Dissolve the iron source, nickel source, morphology modifier and precipitant in a solvent to form a homogeneous precursor solution; 3) Immerse the conductive substrate treated in step 1) into the precursor solution prepared in step 2), heat and react, remove the conductive substrate, clean and dry it to obtain a substrate loaded with the precursor. 4) The substrate treated in step 3) is placed in a controlled atmosphere for heat treatment, and then Fe is grown on the substrate by controlling the cooling method. 1.7 Ni 1.43 O4 defective electrocatalyst.

2. The Fe according to claim 1 1.7 Ni 1.43 An atmosphere-controlled synthesis method for O4-deficient electrocatalysts, characterized in that... In step 4), the controllable atmosphere is an inert gas, air, or an O2 / N2 mixed atmosphere with controllable oxygen partial pressure; In step 4), the controllable atmosphere is an O2 / N2 mixed atmosphere with controllable oxygen partial pressure, wherein the volume fraction of O2 is 1-20%.

3. A Fe according to claim 1 or 2 1.7 Ni 1.43 An atmosphere-controlled synthesis method for O4-deficient electrocatalysts, characterized in that... In step 4), the heat treatment is to keep the temperature at 300-600℃ for 1-6 hours, with a heating rate of 2-10℃ / min.

4. The Fe according to claim 1 1.7 Ni 1.43 An atmosphere-controlled synthesis method for O4-deficient electrocatalysts, characterized in that... In step 4), the cooling method is any one of rapid quenching, controlled-speed cooling, or atmosphere switching cooling.

5. The Fe according to claim 1 1.7 Ni 1.43 An atmosphere-controlled synthesis method for O4-deficient electrocatalysts, characterized in that... In step 2), the iron source is ferric nitrate, and the nickel source is nickel acetate; The molar ratio of the iron source to the nickel source is 1.2:

1.

6. A Fe according to claim 1 or 5 1.7 Ni 1.43 An atmosphere-controlled synthesis method for O4-deficient electrocatalysts, characterized in that... In step 2), the morphology control agent is ammonium fluoride; The precipitant is urea.

7. The Fe according to claim 1 1.7 Ni 1.43 An atmosphere-controlled synthesis method for O4-deficient electrocatalysts, characterized in that... In step 3), the heating reaction is either a hydrothermal reaction or a solvothermal reaction; The heating reaction is carried out at a temperature of 150-200℃ for 2-12 hours.

8. The Fe according to claim 3 1.7 Ni 1.43 An atmosphere-controlled synthesis method for O4-deficient electrocatalysts, characterized in that... In step 1), the conductive substrate is nickel foam.

9. A Fe 1.7 Ni 1.43 O4-defective electrocatalyst, characterized in that... The electrocatalyst is prepared by the atmosphere-controlled synthesis method according to any one of claims 1-8. The electrocatalyst is a self-supporting heterojunction material grown on a three-dimensional porous conductive substrate, and has a nanosheet array morphology and a defect structure with cation vacancies and mixed valence states.

10. A Fe as described in claim 9 1.7 Ni 1.43 The application of O4-deficient electrocatalysts in electrochemical water splitting reactions is characterized by: The electrocatalyst serves as the working electrode for catalyzing the oxygen evolution reaction and / or the hydrogen evolution reaction.

Images