Stainless steel loaded cobalt-nickel bimetallic phosphide catalyst
Through the preparation of stainless steel-supported cobalt-nickel bimetallic phosphide catalyst, the problems of insufficient exposure of existing catalyst active sites and lack of bifunctional mechanisms are solved, and the effect of efficient electrocatalytic synthesis of ammonia and low energy consumption is achieved.
Patent Information
- Application Number
- CN202510448448.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-10
- Publication Date
- 2025-07-08
AI Technical Summary
Existing phosphide catalysts have insufficient exposure to active sites and lack of bifunctional mechanisms in electrocatalytic nitrate reduction reactions, resulting in low ammonia synthesis efficiency and high energy consumption.
The stainless steel-loaded cobalt-nickel bimetallic phosphide catalyst is prepared by hydrothermal reaction and tube furnace heating to form a CoP-Ni2P nanowire structure, combining the corrosion resistance and high strength of the stainless steel substrate to achieve efficient combination of the catalyst.
Under neutral electrolyte, the CoP-Ni2P/SS catalyst exhibits superior electrocatalytic synthesis performance, with ammonia yield as high as 5368.53μg h-1cm-2, Faraday efficiency reaching 96.21%, and ammonia synthesis with a high power density of 2.84mW·cm-2 was achieved in zinc-nitrate batteries.
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Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of electrocatalytic materials, and particularly relates to the preparation of a stainless-steel supported cobalt-nickel bimetallic phosphide catalyst and its application in electrocatalytic ammonia synthesis. Background Art
[0002] As one of the largest globally produced chemical products, ammonia is not only the cornerstone of the fertilizer industry, but also regarded as the most promising green hydrogen energy carrier due to its high hydrogen storage density of 17.6 wt% and liquefaction critical temperature of -33.4 °C. In addition, the complete combustion products of ammonia are only nitrogen and water, making it irreplaceable in the field of clean energy storage and transportation. Currently, the industrial synthesis of ammonia highly depends on the Haber-Bosch process, which requires harsh conditions of high temperature (400 - 600 °C) and high pressure (200 - 350 atm), and a large amount of CO2, up to 450 million tons, about 1% of the global CO2 emissions, is emitted during the preparation of H2 raw materials, continuously exacerbating global energy consumption and the greenhouse effect. Synthesizing ammonia by electrocatalytic nitrate reduction reaction (eNITRR) can convert nitrate pollutants into ammonia at normal temperature and pressure, realizing the dual-functional coupling of "wastewater treatment - energy production". This technology uses water as the proton source and directly converts the electrical energy of renewable energy into chemical bond energy, having obvious environmental friendliness and cost-benefit advantages.
[0003] Currently, transition metals are widely used in the eNITRR field due to their abundant content, low cost, and unique d-electron orbitals. Among them, transition metal phosphides have become the most promising candidate materials for industrialization due to their metal-like conductivity and corrosion resistance. Existing phosphide catalysts still face insufficient exposure of active sites and the lack of a bifunctional mechanism. Based on the above, the present invention provides a preparation method for a stainless-steel supported cobalt-nickel bimetallic phosphide catalyst, which has a simple preparation process, low cost, and can effectively improve the eNITRR performance, having important research value and broad application prospects. Summary of the Invention
[0004] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide the preparation of a stainless-steel supported cobalt-nickel bimetallic phosphide catalyst and its application in electrocatalytic ammonia synthesis, and the prepared self-supporting electrode can be directly applied to a proton exchange membrane electrolyzer.
[0005] To achieve the above purpose, the present invention adopts the following technical solutions:
[0006] A preparation method for a stainless-steel supported cobalt-nickel bimetallic phosphide catalyst, comprising the following steps:
[0007] (1) Dissolve a certain amount of Co(NO3)2·6H2O, Ni(NO3)2·6H2O and CH4N2O in deionized water respectively, and then stir and mix them thoroughly to prepare a mixed solution;
[0008] (2) vertically immerse a piece of pretreated stainless steel (SS) into the solution;
[0009] (3) transferring the solution to a reaction kettle for hydrothermal reaction. After the reaction is completed, the sample is washed with water and ethanol several times and then vacuum dried to obtain a precursor.
[0010] (4) The dried NaH2PO2·H2O and the precursor were placed in a tube furnace in turn, and then argon gas was introduced for heating reaction. After the tube furnace was cooled, the sample was washed with water and ethanol several times, and then vacuum dried. It was recorded as CoP-Ni2P / SS.
[0011] Furthermore, the total molar amount of Co(NO3)2·6H2O and Ni(NO3)2·6H2O added in step (1) is 2 mmol.
[0012] Furthermore, in step (1), the amount of CH4N2O added is 10 mmol, and the amount of deionized water added is 30 mL.
[0013] Furthermore, in step (2), the SS substrate material is pretreated with hydrochloric acid, ethanol and ultrapure water in sequence.
[0014] Furthermore, the temperature of the hydrothermal reaction in step (3) is 120° C. and the time is 8 hours.
[0015] Furthermore, the drying temperature in step (3) is 60° C. and the drying time is 12 h.
[0016] Furthermore, in step (4), NaH2PO2·H2O is placed upstream of the reaction gas flow, and the precursor is placed downstream of the reaction gas flow.
[0017] Furthermore, in step (4), the amount of NaH2PO2·H2O added is 0.6 g.
[0018] Furthermore, the heating temperature of the tube furnace in step (4) is 300°C, the time is 2h, and the heating rate is 2°C min -1 .
[0019] Furthermore, in step (4), the drying temperature is 60° C. and the drying time is 12 h.
[0020] Compared with the prior art, the present invention has the following beneficial effects:
[0021] 1. The present invention uses an industrial-grade stainless steel substrate and common metal salts as raw materials, with relatively low comprehensive material costs. Through an integrated in-situ growth technology, the preparation cycle from substrate treatment to catalyst forming is short and the repeatability is good.
[0022] 2. The present invention selects stainless steel as the CoP-Ni2P substrate. Under neutral electrolyte, its ammonia production rate is more excellent than that of carbon cloth and nickel foam as the CoP-Ni2P substrate. The stainless steel substrate has comprehensive advantages such as corrosion resistance, high strength, easy functionalization and economy (the price is only 1 / 3 of that of nickel foam). In addition, the stainless steel substrate can withstand the high temperature required for the phosphidation reaction, and its high-temperature oxidation resistance is significantly better than that of carbon-based materials (which are easily oxidized and deactivated at high temperatures) and nickel foam (which is easily embrittled at high temperatures). In the traditional coating process, the phosphide can be tightly bonded to the stainless steel without any polymer adhesive, and has good interfacial properties.
[0023] 3. The stainless steel-supported cobalt-nickel bimetallic phosphide catalyst prepared by the present invention shows excellent eNITRR ammonia synthesis performance under neutral electrolyte. Among them, at the optimal reaction potential of -0.5V vs. RHE, the ammonia production rate of CoP-Ni2P / SS is 5368.53 μg h -1 cm -2 , and the Faraday efficiency can reach 96.21%. The performance advantage stems from its CoP-Ni2P bifunctional active sites, as well as a large active surface area, good electronic conductivity and high charge transfer rate.
[0024] 4. The zinc-nitrate battery assembled by the CoP-Ni2P / SS prepared by the present invention and a zinc sheet realizes power supply while performing eNITRR ammonia synthesis. The power density of this battery is 2.84 mW·cm -2 , and the ammonia production rate can reach 56.76 μmol h -1 cm -2 , systematically broadening the application field of zinc-based batteries and having the potential to develop new zinc-based batteries. Description of the Drawings
[0025] Figure 1 XRD patterns of the stainless steel-supported cobalt-nickel bimetallic catalysts prepared in Examples 1-4 and the CoP / SS and Ni2P / SS catalysts prepared in Comparative Examples 1 and 2.
[0026] Figure 2SEM images of the stainless-steel supported cobalt-nickel bimetallic catalysts prepared in Examples 1-4 and the CoP / SS and Ni2P / SS catalysts prepared in Comparative Examples 1 and 2. Among them, (a) is the SEM image of Ni2P / SS, (b) is the SEM image of CoP / SS, (c) is the SEM image of CoP-3Ni2P / SS, (d) is the SEM image of CoP-Ni2P / SS, (e) is the SEM image of 3CoP-Ni2P / SS, and (f) is the SEM image of 6CoP-Ni2P / SS.
[0027] Figure 3 TEM and HRTEM images of the CoP-Ni2P / SS catalyst prepared in Example 1.
[0028] Figure 4 XPS spectra of the CoP-Ni2P / SS catalyst prepared in Example 1 and the Ni2P / SS and CoP / SS catalysts prepared in Comparative Examples 1 and 2.
[0029] Figure 5 Ammonia production rate and FE of the stainless-steel supported cobalt-nickel bimetallic catalysts prepared in Examples 1-4 and the CoP / SS and Ni2P / SS catalysts prepared in Comparative Examples 1 and 2 in 0.5 M Na2SO4 electrolyte containing 0.1 M NaNO3 at -0.5 V vs. RHE.
[0030] Figure 6 Ammonia production stability measurement of the CoP-Ni2P / SS catalyst prepared in Example 1.
[0031] Figure 7 Comparison of the electrochemically active surface area (ECSA) of the stainless-steel supported cobalt-nickel bimetallic catalysts prepared in Examples 1-4 and the CoP / SS and Ni2P / SS catalysts prepared in Comparative Examples 1 and 2. Among them, (a-f) are the CV curves of CoP-3Ni2P / SS, CoP-Ni2P / SS, 3CoP-Ni2P / SS, 6CoP-Ni2P / SS, Ni2P / SS, and CoP / SS at different scan rates; (g) is the C dl ; (h) is the ECSA of CoP-3Ni2P / SS, CoP-Ni2P / SS, 3CoP-Ni2P / SS, 6CoP-Ni2P / SS, Ni2P / SS, and CoP / SS.
[0032] Figure 8 Impedance comparison of the CoP-Ni2P / SS catalyst prepared in Example 1 and the CoP / SS and Ni2P / SS catalysts prepared in Comparative Examples 1 and 2.
[0033] Figure 9 Comparison of ammonia production performance of the CoP-Ni2P / SS catalyst prepared in Example 1 and the CoP-Ni2P / CF and CoP-Ni2P / NF catalysts prepared in Comparative Examples 3 and 4.
[0034] Figure 10 Device diagram of a zinc-nitrate battery assembled with the CoP-Ni2P / SS catalyst prepared in Example 1 and a zinc sheet.
[0035] Figure 11 Performance of the zinc-nitrate battery assembled with the CoP-Ni2P / SS catalyst prepared in Example 1 and a zinc sheet. (a) Discharge polarization curve and power density; (b) Ammonia production rate obtained at different current densities. Specific embodiments
[0036] To make the content of the present invention easier to understand, the technical solutions of the present invention are further described below in conjunction with specific embodiments, but the present invention is not limited thereto.
[0037] Example 1
[0038] (1) First, a 2 cm × 3 cm SS was ultrasonically cleaned with 2 M hydrochloric acid, ethanol, and ultrapure water for 10 minutes in sequence, and then dried as a conductive substrate.
[0039] (2) 1 mmol of Co(NO3)2·6H2O, 1 mmol of Ni(NO3)2·6H2O, and 10 mmol of CH4N2O were dissolved in 30 mL of H2O, and the mixture formed a homogeneous solution. Then the solution was transferred to a 50 mL autoclave, and a pretreated SS was vertically immersed in the solution. The assembled autoclave was maintained at 120 °C for 8 hours. After the autoclave cooled down, the obtained precursor was washed several times with water and ethanol, and then dried under vacuum. Subsequently, the dried precursor and 0.6 g of NaH2PO2·H2O were placed in two separate porcelain boats, and heated at a heating rate of 2 °C min -1 at 300 °C for 2 h in an argon atmosphere, where NaH2PO2·H2O was placed upstream of the reaction gas flow, and the precursor was downstream of the reaction gas flow, and a copper sulfate absorption solution was provided at the end of the tubular furnace. After the temperature of the tubular furnace dropped to room temperature after the program ended, the sample was taken out, and the stainless steel-supported cobalt-nickel bimetallic catalyst, denoted as CoP-Ni2P / SS, was obtained through washing and drying.
[0040] Example 2
[0041] Change the addition amount of Co(NO3)2·6H2O to 1 mmol and the addition amount of Ni(NO3)2·6H2O to 3 mmol. Keep other preparation steps and reaction conditions the same as those in Example 1. The finally obtained stainless-steel supported cobalt-nickel bimetallic catalyst is denoted as CoP-3Ni2P / SS.
[0042] Example 3
[0043] Change the addition amount of Co(NO3)2·6H2O to 3 mmol and the addition amount of Ni(NO3)2·6H2O to 1 mmol. Keep other preparation steps and reaction conditions the same as those in Example 1. The finally obtained stainless-steel supported cobalt-nickel bimetallic catalyst is denoted as 3CoP-Ni2P / SS.
[0044] Example 4
[0045] Change the addition amount of Co(NO3)2·6H2O to 6 mmol and the addition amount of Ni(NO3)2·6H2O to 1 mmol. Keep other preparation steps and reaction conditions the same as those in Example 1. The finally obtained stainless-steel supported cobalt-nickel bimetallic catalyst is denoted as 6CoP-Ni2P / SS.
[0046] Comparative Example 1
[0047] During the hydrothermal reaction process, do not add Ni(NO3)2·6H2O. Keep other preparation steps and reaction conditions the same as those in Example 1, and it is denoted as CoP / SS.
[0048] Comparative Example 2
[0049] During the hydrothermal reaction process, do not add Co(NO3)2·6H2O. Keep other preparation steps and reaction conditions the same as those in Example 1, and it is denoted as Ni2P / SS.
[0050] Comparative Example 3
[0051] Replace the stainless-steel substrate with carbon cloth. Keep other preparation steps and reaction conditions the same as those in Example 1, and it is denoted as CoP-Ni2P / CF.
[0052] Comparative Example 4
[0053] Replace the stainless-steel substrate with nickel foam. Keep other preparation steps and reaction conditions the same as those in Example 1, and it is denoted as CoP-Ni2P / NF.
[0054] The electrochemical performance tests of the catalysts prepared in the present invention are all completed on a three-electrode system. The prepared catalyst is used as the working electrode, and its working area is 1 cm 2 , a platinum sheet (1 cm × 1 cm) is used as the counter electrode, and a saturated calomel electrode (SCE) is used as the reference electrode. According to the Nernst equation (ERHE = E SCE + 0.0591pH + 0.242 V, pH = 7) can convert the measured potential from relative to SCE to a scale relative to the reversible hydrogen electrode (RHE). The electrolyte in the H-type electrolytic cell is a 50 mL solution of 0.5 M Na2SO4 containing 100 mM NaNO3. Before performing the electrochemical test, argon gas needs to be continuously introduced into the cathode cell for half an hour to remove impurity gases in the electrolytic cell, and the entire electrochemical test process also needs to be carried out in an argon atmosphere.
[0055] Figure 1 XRD patterns of the stainless steel-supported cobalt-nickel bimetallic catalysts prepared in Examples 1-4 and the CoP / SS and Ni2P / SS catalysts prepared in Comparative Examples 1 and 2. It can be seen from Figure (a) that Ni2P / SS and CoP / SS match well with Ni2P (PDF#03-0953) and CoP (PDF#29-0497) respectively. Figure (b) shows that the diffraction peaks of CoP-3Ni2P / SS, CoP-Ni2P / SS, 3CoP-Ni2P / SS, and 6CoP-Ni2P / SS match the characteristic diffraction peaks of Ni2P and CoP. Among them, the three strong diffraction peaks located at 43.4°, 50.67°, and 74.55° belong to the substrate stainless steel, and the substrate peaks of different samples are consistent, indicating the stability of the stainless steel composition. In addition, in the figure, as the Co / Ni metal ratio is different, the intensity of the diffraction peaks changes. At a low Co / Ni molar ratio, the peak of Ni2P is stronger, and as the Co content increases, the peak of CoP gradually increases.
[0056] Figure 2 SEM images of the stainless steel-supported cobalt-nickel bimetallic catalysts prepared in Examples 1-4 and the CoP / SS and Ni2P / SS catalysts prepared in Comparative Examples 1 and 2. It can be seen from the figure that Ni2P / SS and CoP / SS respectively exhibit nanosheet and nanowire structures; CoP-3Ni2P / SS does not exhibit nanosheet or nanowire structures and the surface becomes rough; CoP-Ni2P / SS, 3CoP-Ni2P / SS, and 6CoP-Ni2P / SS exhibit nanowire structures. Among them, the nanowire structure of CoP-Ni2P / SS is the thinnest, with a high specific surface area, which can provide more active sites and is beneficial to the reaction.
[0057] Figure 3 TEM and HRTEM images of the CoP-Ni2P / SS catalyst prepared in Example 1. It can be seen from the figure that the diameter of the nanowire structure of CoP-Ni2P / SS is about 70 nm, and its HRTEM image has clear lattice fringes, corresponding to the CoP (111) plane and the Ni2P (210) plane respectively.
[0058] Figure 4 XPS spectra of the CoP-Ni2P / SS catalyst prepared in Example 1 and the Ni2P / SS and CoP / SS catalysts prepared in Comparative Examples 1 and 2. As can be seen from Figure (a), the surfaces of the CoP / SS, Ni2P / SS, and CoP-Ni2P / SS catalysts contain Co / Ni, P, O, and C elements respectively. The residual oxygen content is due to the surface oxidation of the catalyst in air; as can be seen from Figure (b), the Co 2p characteristic peak of CoP-Ni2P / SS is slightly shifted towards higher binding energy, indicating the formation of Co 2+ / 3+ hydroxides and oxides on its larger surface domain; as can be seen from Figure (c), the P 2p characteristic peak of CoP-Ni2P / SS is shifted towards lower binding energy. The above results show that some electrons are transferred from Co / Ni to P. During the eNITRR process, Co / Ni can serve as the adsorption nitrate or intermediate site, and P can serve as the proton site. The transfer of electrons from Co / Ni to P is beneficial to the adsorption and desorption of reaction intermediates and conducive to the catalytic reaction.
[0059] Figure 5 Ammonia production rates and FEs of the stainless steel-supported cobalt-nickel bimetallic catalysts prepared in Examples 1-4 and the CoP / SS and Ni2P / SS catalysts prepared in Comparative Examples 1 and 2 in a 0.5 M Na2SO4 electrolyte containing 0.1 M NaNO3 at a voltage of -0.5 V vs. RHE. As can be seen from the figure, compared with the Ni2P / SS and CoP / SS catalysts, the ammonia production rates and FEs of the CoP-3Ni2P / SS, CoP-Ni2P / SS, 3CoP-Ni2P / SS, and 6CoP-Ni2P / SS catalysts have been improved. Among them, CoP-Ni2P / SS exhibits better eNITRR ammonia synthesis performance. At a potential of -0.5 V vs. RHE, its ammonia production rate is 5368.53 μg h -1 cm -2 -1, and the FE can reach 96.21%.
[0060] Figure 6 Determination of the ammonia production stability of the CoP-Ni2P / SS catalyst prepared in Example 1. As can be seen from the figure, the ammonia production rate and FE of CoP-Ni2P / SS show slight fluctuations within 10 cycles and no obvious decrease, indicating that CoP-Ni2P / SS has excellent and stable eNitRR performance.
[0061] Figure 7 Comparison of the electrochemically active specific surface areas (ECSAs) of the stainless steel-supported cobalt-nickel bimetallic catalysts prepared in Examples 1-4 and the CoP / SS and Ni2P / SS catalysts prepared in Comparative Examples 1 and 2. As can be seen from the figure, the ECSA value of CoP-Ni2P / SS is 614.25 cm2 Greater than CoP-3Ni2P / SS(424.75 cm 2 ), 3CoP-Ni2P / SS(558.75 cm 2 ), 6CoP-Ni2P / SS(587.5 cm 2 ), Ni2P / SS(10.22 cm 2 ), and CoP / SS(18.23 cm 2 ), indicating that the slender nanowire structure of the CoP-Ni2P / SS catalyst is more conducive to the infiltration of nitrate solution and exposes more active surface area. It further proves that CoP-Ni2P / SS can interact more effectively with the nitrate electrolyte and has better catalytic efficiency.
[0062] Figure 8 Impedance comparison of the CoP-Ni2P / SS catalyst prepared in Example 1 and the CoP / SS and Ni2P / SS catalysts prepared in Comparative Examples 1 and 2. It can be seen from the figure that the semicircle diameter of CoP-Ni2P / SS is significantly smaller, indicating good electron conductivity and charge transfer efficiency between its electrolyte and electrode interface, further proving that the CoP-Ni2P / SS catalyst is more conducive to the eNitRR ammonia synthesis reaction.
[0063] Figure 9 Ammonia production performance comparison of the CoP-Ni2P / SS catalyst prepared in Example 1 and the CoP-Ni2P / CF and CoP-Ni2P / NF catalysts prepared in Comparative Examples 3 and 4. It can be seen from the figure that at a potential of -0.5 V vs. RHE, the ammonia production rate of CoP-Ni2P / SS is higher than that of CoP-Ni2P / CF and CoP-Ni2P / NF, indicating that using stainless steel as the CoP-Ni2P substrate is more conducive to the eNITRR ammonia synthesis reaction.
[0064] Figure 10 Schematic diagram of the zinc-nitrate battery device assembled with the CoP-Ni2P / SS catalyst prepared in Example 1 and a zinc sheet. It can be seen from the figure that the assembled zinc-nitrate battery uses the CoP-Ni2P / SS catalyst as the positive electrode and the zinc sheet (1 cm × 1 cm) as the negative electrode. The reaction is carried out in an H-type electrolytic cell separated by a Nafion 117 proton membrane, containing 50 mL of cathode electrolyte (0.1 M NaNO3 + 0.5 M Na2SO4) and 50 mL of anode electrolyte (1 M NaOH).
[0065] Figure 11 Performance of the zinc-nitrate battery assembled with the CoP-Ni2P / SS catalyst prepared in Example 1 and a zinc sheet. It can be seen from Figure (a) that the maximum power density of this battery reaches 2.84 mW cm-2 , showing good power density. As can be seen from Figure (b), after the constant current test of the battery, the cathode electrolyte was collected for ammonia production measurement. The ammonia production rate increased with the increase of the current density. When the current density was 10 mA cm -2 , the ammonia production rate was 56.76 μmol h -1 cm -2 . The zinc-nitrate battery based on CoP-Ni2P / SS not only realizes power output but also ammonia synthesis during the reaction process, showing the potential for developing new zinc-based batteries.
[0066] As mentioned above, the above are only specific embodiments of the present invention with relatively good creativity. However, the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.
Claims
1. A preparation method of a stainless steel supported cobalt-nickel bimetallic phosphide catalyst, characterized in that: It includes the following steps: (1) Dissolve Co(NO3)2·6H2O, Ni(NO3)2·6H2O and CH4N2O in deionized water respectively, and then fully stir and mix them to make a mixed solution; (2) Vertically immerse a piece of pretreated stainless steel into the mixed solution; (3) Carry out hydrothermal reaction, cool, wash with water and ethanol, and dry in vacuum to obtain a precursor; (4) Heat the dried NaH2PO2·H2O and the precursor in an argon atmosphere, cool, wash with water and ethanol, and dry in vacuum to prepare the stainless steel supported cobalt-nickel bimetallic phosphide catalyst CoP-Ni2P / SS.
2. The preparation method of the stainless steel supported cobalt-nickel bimetallic phosphide catalyst according to claim 1, characterized in that: In step (1), the molar ratio of the sum of Co(NO3)2·6H2O and Ni(NO3)2·6H2O to CH4N2O is 2:10, and the molar ratio of Co to Ni is 1-6:1-3.
3. The preparation method of the stainless steel supported cobalt-nickel bimetallic phosphide catalyst according to claim 1, characterized in that: In step (2), the stainless steel is pretreated with hydrochloric acid, ethanol and ultrapure water in sequence.
4. The preparation method of the stainless steel supported cobalt-nickel bimetallic phosphide catalyst according to claim 1, characterized in that: In step (3), the temperature of the hydrothermal reaction is 120 °C and the time is 8 h; the drying temperature is 60 °C and the time is 12 h.
5. The preparation method of the stainless steel supported cobalt-nickel bimetallic phosphide catalyst according to claim 1, characterized in that: In step (4), NaH2PO2·H2O is placed upstream of the reaction gas stream, and the precursor is placed downstream of the reaction gas stream.
6. The preparation method of the stainless steel supported cobalt-nickel bimetallic phosphide catalyst according to claim 1, characterized in that: In step (4), the mass ratio of NaH2PO2·H2O to the precursor is 100:
97.
7. The preparation method of the stainless steel supported cobalt-nickel bimetallic phosphide catalyst according to claim 1, characterized in that: In step (4), the heating temperature is 300 °C, the time is 2 h, and the heating rate is 2 °C / min; the drying temperature is 60 °C and the time is 12 h.
8. A stainless steel supported cobalt-nickel bimetallic phosphide catalyst prepared by the method according to any one of claims 1 to 7.
9. Application of a stainless steel supported cobalt-nickel bimetallic phosphide catalyst prepared by the method according to any one of claims 1 to 7 in electrocatalytic ammonia synthesis.