Nickel-tin alloy-oxide composite material Ni3Sn2-NiSnOx, preparation method thereof and application of nickel-tin alloy-oxide composite material Ni3Sn2-NiSnOx in electrocatalytic synthesis ammonia reaction

Abstract

The invention discloses a nickel-tin alloy-oxide composite material Ni3Sn2-NiSnOx, a preparation method thereof and application of the nickel-tin alloy-oxide composite material Ni3Sn2-NiSnOx in electrocatalytic ammonia synthesis reaction, and belongs to the technical field of electrochemical catalysis. The preparation method comprises the following steps: adding SnCl2. 2H2O and NiCl into deionized water as raw materials, adding glycine, potassium pyrophosphate and urea as electro-deposition auxiliary agents, and stirring for 10 minutes to obtain electro-deposition liquid; and carrying out electro-deposition on a conductive substrate serving as a cathode, so that Ni and Sn are co-deposited to form a nickel-tin alloy, and part of the nickel-tin alloy reacts with oxygen in the deposition process or after deposition to form a nickel-tin oxide phase, so that the Ni3Sn2-NiSnOx composite catalytic material is obtained. By regulating and controlling the concentration of tin ions in the electroplating solution and the electrodeposition time, the component proportion of nickel and tin in the product and the morphology structure of the material can be regulated. The composite material provided by the invention has excellent electrocatalytic nitrogen reduction synthesis ammonia activity and selectivity, and solves the problems that the service life of a catalyst is shortened and the catalytic activity and stability are reduced due to irreversible reconstruction of an alloy compound under high potential.

Description

Technical Field

[0001] The present invention relates to the field of electrochemical catalysis, and in particular to a nickel-tin alloy-oxide composite material Ni3Sn2-NiSnO x Its preparation method and application in electrocatalytic ammonia synthesis reaction. Background Art

[0002] Ammonia (NH3) is an important chemical raw material, widely used in agricultural fertilizer and chemical production. Traditionally, ammonia synthesis relies primarily on the Haber-Bosch process, which involves the direct synthesis of ammonia from nitrogen and hydrogen using an iron-based catalyst under high temperature and pressure. While the Haber process has enabled large-scale industrial ammonia production, it consumes significant amounts of energy and is associated with significant carbon dioxide emissions, placing a strain on the environment. Consequently, alternative methods for ammonia synthesis under milder conditions are attracting increasing attention.

[0003] To improve the efficiency of ammonia electrosynthesis, various catalyst materials have been explored, including precious metals (such as Ru-based catalysts), transition metal nitrides, and metal sulfides. However, these catalysts often have problems such as high cost or insufficient performance. Nickel (Ni), as an inexpensive and abundant transition metal, has good conductivity and catalytic activity. However, due to competition with the hydrogen evolution reaction (HER), pure Ni electrodes have poor selectivity for nitrogen reduction in aqueous solution. Therefore, it is difficult to achieve efficient ammonia synthesis with a single nickel-based catalyst. In recent years, researchers have attempted to introduce a second component into nickel to improve its ammonia catalytic performance. Tin (Sn), a metal with low activity in the hydrogen evolution reaction, is used to suppress the by-product hydrogen in the electrocatalytic reduction reaction. Incorporating tin into nickel is expected to reduce the hydrogen production tendency on the nickel surface, thereby improving the selectivity of nitrogen reduction. The presence of tin may provide additional active sites for nitrogen adsorption or change the adsorption behavior of reaction intermediates, thereby facilitating nitrogen activation.

[0004] The introduction of an oxide phase onto the catalyst surface can often influence the electrocatalytic reaction pathway, providing different adsorption sites or forming interfacial synergistic interactions with the metal phase. Therefore, composite materials containing a nickel-tin alloy phase and an oxide phase are expected to combine the advantages of metal and oxide catalysis to improve the efficiency of electrocatalytic ammonia synthesis. Summary of the Invention

[0005] In view of the shortcomings of the background technology, the present invention discloses a nickel-tin alloy-oxide composite material Ni3Sn2-NiSnO x The present invention relates to a composite material, a preparation method thereof, and its application in electrocatalytic ammonia synthesis, which solves the aforementioned problems and exhibits excellent electrocatalytic nitrogen reduction ammonia synthesis activity and selectivity. This composite material solves the problem that irreversible reconstruction of alloy compounds at high potentials can shorten the catalyst's service life and reduce catalytic activity and stability.

[0006] The present invention provides a nickel-tin alloy-oxide composite material Ni3Sn2-NiSnO x The preparation method comprises the following steps:

[0007] S101, select SnCl2·2H2O as tin source, NiCl2 as nickel source, dissolve them in a solution containing electrodeposition auxiliary agent to prepare Ni-containing 2+ and Sn 2+ Electrodeposition solution;

[0008] S102, applying a constant current to the nickel foam substrate as a cathode to perform electrodeposition, so that nickel and tin are co-deposited to form a nickel-tin alloy Ni3Sn2, which is partially oxidized during the deposition process to form a nickel-tin oxide phase NiSnO x ;

[0009] S103, take out the deposited cathode and clean and dry it to obtain Ni3Sn2-NiSnO x Composite catalytic materials.

[0010] Add SnCl2·2H2O and NiCl as raw materials to deionized water, add glycine, potassium pyrophosphate, and urea as electrodeposition auxiliary agents, and stir for 10 minutes to obtain an electrodeposition solution. Apply a constant current to a conductive substrate as a cathode for electrodeposition, so that Ni and Sn co-deposit to form a nickel-tin alloy, and partially react with oxygen during or after deposition to form a nickel-tin oxide phase. Take out the obtained electrode and wash and dry it to obtain Ni3Sn2-NiSnO x Composite catalytic materials. By regulating the concentration of tin ions in the electroplating solution and the electrodeposition time, the ratio of nickel and tin in the product and the morphology of the material can be adjusted.

[0011] Preferably, the molar ratio of glycine, potassium pyrophosphate, and urea is 1:3:6. In the electrodeposition solution, the concentrations of glycine, potassium pyrophosphate, and urea are 0.01 mol / L, 0.03 mol / L, and 0.06 mol / L, respectively. This ratio can effectively adjust the reaction conditions, promote the deposition of the nickel-tin alloy, and ensure a uniform product.

[0012] Preferably, in step S101, the molar ratio of SnCl2·2H2O to NiCl2 is (0.5-2):1, and in the electrodeposition solution, Ni 2+ and Sn 2+ The concentration of nickel-tin alloy is 0.005-0.02 mol / L. This ratio can effectively adjust the reaction conditions, promote the deposition of nickel-tin alloy, and ensure uniform product.

[0013] Preferably, in step S102, the electrodeposition time is maintained at 10 minutes, which can effectively control the deposition amount of the alloy phase and avoid excessive crystal synthesis leading to a decrease in catalytic performance.

[0014] Preferably, in step S102, the temperature during electrodeposition is maintained at 30°C.

[0015] Preferably, in step S102, the current during electrodeposition is -0.24 A. This constant current helps ensure uniform deposition of the material and uniformity of the alloy-oxide.

[0016] The present invention also provides a nickel-tin alloy-oxide composite material Ni3Sn2-NiSnO prepared by the above preparation method x The nickel-tin alloy-oxide composite material Ni3Sn2-NiSnO x Used in electrocatalytic ammonia synthesis reaction.

[0017] Therefore, the present invention provides a nickel-tin alloy-oxide composite material Ni3Sn2-NiSnO x Its preparation method and application in electrocatalytic ammonia synthesis reaction have the following beneficial effects:

[0018] Ni3Sn2-NiSnO of the present invention x The composite catalyst is prepared using a one-step electrochemical deposition process, eliminating the need for high temperatures, high pressures, or complex processes. The method is simple and controllable, allowing precise control of the catalyst composition and structure by adjusting deposition parameters such as the ratio of Sn and Ni raw materials and electrodeposition time. The catalyst is composed of inexpensive and readily available Ni and Sn, contains no precious metals, and offers low material costs and abundant raw materials.

[0019] The Ni3Sn2-NiSnO synthesized by the present invention x The composite catalyst features a nickel-tin alloy / oxide interface. In 100 mL of electrodeposition solution, the raw material ratio of SnCl₂·2H₂O to NiCl₂ was controlled at 1:1, and the deposition time was limited to 10 minutes to avoid incomplete deposition. The deposited product under these conditions is a succulent-like crystalline material with regular surface protrusions, which help provide more active sites. The uniformly grown nickel-tin alloy effectively improves the selectivity and activity of the nitrogen reduction reaction, significantly enhancing the efficiency of electrocatalytic ammonia synthesis.

[0020] The Ni3Sn2-NiSnO synthesized by the present invention xThe superior performance of the composite catalyst may be attributed to the fact that the introduction of Sn can reduce the d-band center of Ni, reducing the strong adsorption of H, thereby reducing competition for the HER and improving the Faradaic efficiency (FE) of the NRR. The combination of the NiSn alloy and the oxide creates more interfacial active sites, which promote electron transfer and optimize the activation pathway of N2, further enhancing the reaction activity. The presence of the oxide may lead to electron localization on the surface of the NiSn alloy. The introduction of the NiSn alloy may also generate a certain strain field at the alloy-oxide interface, which can modulate the electronic structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The present invention is a nickel-tin alloy-oxide composite material Ni3Sn2-NiSnO x Preparation method flow chart;

[0022] Figure 2 The Ni3Sn2-NiSnO provided in Example 2 of the present invention x Scanning electron microscopy (SEM) images of the composite material;

[0023] Figure 3 The scanning electron microscope mapping (SEM mapping) patterns of the composite catalyst materials provided in Examples 1-5 of the present invention are as follows;

[0024] Figure 4 The Ni3Sn2-NiSnO provided in Example 2 of the present invention x -1 X-ray diffraction (XRD) pattern of the composite catalyst material;

[0025] Figure 5 The Ni3Sn2-NiSnO provided by the embodiment of the present invention x Comparison of catalytic performance of composite catalyst materials, where a is Ni3Sn2-NiSnO x -1 composite material in N2, Ar atmosphere LSV curve comparison, b is the Ni3Sn2-NiSnOx-1, Ni3Sn2-NiSnO prepared by the present invention x -2, Ni3Sn2-NiSnO x -3 composite materials compared to Ni-NiO x and Sn-NiSnO x Ammonia production performance under different voltages, c is Ni3Sn2-NiSnOx-1, Ni3Sn2-NiSnO prepared by the present invention x -2, Ni3Sn2-NiSnO x -3 composite materials compared to Ni-NiO x and Sn-NiSnO xFaraday efficiency at different voltages; d is Ni3Sn2-NiSnO prepared by the present invention x -2 Stability of composite materials. DETAILED DESCRIPTION

[0026] As the instruction manual Figure 1 As shown, the present invention provides a nickel-tin alloy-oxide composite material Ni3Sn2-NiSnO x The preparation method comprises adding SnCl2·2H2O and NiCl as raw materials to deionized water, adding glycine, potassium pyrophosphate, and urea as electrodeposition auxiliary agents, and stirring for 10 minutes to obtain an electrodeposition solution. A constant current is applied to a conductive substrate serving as a cathode for electrodeposition, so that Ni and Sn are co-deposited to form a nickel-tin alloy, and a portion of the nickel reacts with oxygen during or after the deposition process to form a nickel-tin oxide phase. The obtained electrode is removed and cleaned and dried to obtain Ni3Sn2-NiSnO x Composite catalytic materials. By regulating the concentration of tin ions in the electroplating solution and the electrodeposition time, the ratio of nickel and tin in the product and the morphology of the material can be adjusted.

[0027] The molar ratio of glycine, potassium pyrophosphate and urea is 1:3:6, and the concentrations of glycine, potassium pyrophosphate and urea in the electrodeposition solution are 0.01 mol / L, 0.03 mol / L and 0.06 mol / L, respectively.

[0028] The molar ratio of SnCl2·2H2O to NiCl2 is (0.5-2):1. In the electrodeposition solution, Ni 2+ and Sn 2+ The concentrations are all 0.005-0.02mol / L.

[0029] The electrodeposition time was maintained at 10 min, the temperature was maintained at 30° C., and the current was -0.24 A.

[0030] The present invention also provides a nickel-tin alloy-oxide composite material Ni3Sn2-NiSnO prepared by the above preparation method x , nickel-tin alloy-oxide composite material Ni3Sn2-NiSnO x Used in electrocatalytic ammonia synthesis reaction.

[0031] The present invention will be further described below through specific examples, but it should be understood that these examples are only used for more detailed description and should not be understood as limiting the present invention in any form, that is, they are not intended to limit the scope of protection of the present invention.

[0032] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0033] Example 1

[0034] This embodiment provides a nickel-tin alloy-oxide composite material Ni3Sn2-NiSnO x , its preparation method includes the following steps: take a piece of pretreated nickel foam (length and width of about 2cm × 1cm) as the electroplating substrate (working electrode), a platinum sheet as the counter electrode, and a Hg / HgO electrode as the reference electrode. Prepare the electroplating solution according to the following steps: dissolve 129.6mg NiCl2 in 100mL deionized water, add 75.07mg glycine, 991.02mg potassium pyrophosphate and 360.36mg urea as electroplating auxiliary agents. Stir the electroplating solution at room temperature for 20min. Place the above nickel foam electrode in the electroplating solution at 30°C and electroplating at a constant current of -0.24A for 10min. During the deposition process, it can be observed that a gray-black coating is gradually deposited on the cathode surface. After the deposition is completed, the electrode is taken out, carefully rinsed with anhydrous ethanol and deionized water, and dried to obtain a Ni-NiO loaded thereon. x Nickel foam electrode with composite catalyst material.

[0035] Example 2

[0036] This embodiment provides a nickel-tin alloy-oxide composite material Ni3Sn2-NiSnO x. Its preparation includes the following steps: take a piece of pretreated nickel foam (about 4 cm × 2 cm in length and width) as the electrodeposition substrate (working electrode), a platinum sheet as the counter electrode, and a Hg / HgO electrode as the reference electrode. The electrodeposition solution is prepared according to the following steps: 129.6 mg NiCl2 and 112.815 mg SnCl2·2H2O are dissolved in 100 mL of deionized water, and 75.07 mg glycine, 991.02 mg potassium pyrophosphate and 360.36 mg urea are added thereto as an electrodeposition auxiliary agent. As an electrodeposition auxiliary agent. The electrodeposition solution is stirred at room temperature for 20 minutes. The above-mentioned nickel foam electrode is placed in the electroplating solution at 30°C and electrodeposited at a constant current of -0.24A for 10 minutes. During the deposition process, bubbles (hydrogen) can be observed to escape from the cathode surface, while metal Ni and Sn are gradually deposited to form a gray-black coating. After the deposition is completed, the electrode is taken out, carefully rinsed with deionized water and dried to obtain a nickel foam electrode loaded with Ni3Sn2-NiSnOx-1 composite catalyst material.

[0037] Example 3

[0038] This embodiment provides a nickel-tin alloy-oxide composite material Ni3Sn2-NiSnO x The preparation method includes the following steps: taking a piece of pretreated nickel foam (about 2 cm × 1 cm in length and width) as the electrodeposition substrate (working electrode), a platinum sheet as the counter electrode, and a Hg / HgO electrode as the reference electrode. The electrodeposition solution is prepared according to the following steps: 129.6 mg NiCl2 and 225.63 mg SnCl2·2H2O are dissolved in 100 mL deionized water, and 75.07 mg glycine, 991.02 mg potassium pyrophosphate and 360.36 mg urea are added thereto as electrodeposition auxiliary agents. The electrodeposition solution is stirred at room temperature for 20 minutes. The above nickel foam electrode is placed in the electroplating solution at 30°C and electrodeposited at a constant current of -0.24A for 10 minutes. During the deposition process, it can be observed that a gray-black coating is gradually deposited on the cathode surface. After the deposition is completed, the electrode is taken out, carefully rinsed with anhydrous ethanol and deionized water, and dried to obtain a Ni3Sn2-NiSnO loaded thereon. x -2 composite catalyst material nickel foam electrode.

[0039] Example 4

[0040] This embodiment provides a nickel-tin alloy-oxide composite material Ni3Sn2-NiSnO xThe preparation method includes the following steps: taking a pretreated nickel foam (about 2 cm × 1 cm in length and width) as the electrodeposition substrate (working electrode), a platinum sheet as the counter electrode, and a Hg / HgO electrode as the reference electrode. The electrodeposition solution is prepared according to the following steps: 129.6 mg NiCl2 and 338.445 mg SnCl2·2H2O are dissolved in 100 mL deionized water, and 75.07 mg glycine, 991.02 mg potassium pyrophosphate and 360.36 mg urea are added thereto as electrodeposition auxiliary agents. The electrodeposition solution is stirred at room temperature for 20 minutes. The nickel foam electrode is placed in the electroplating solution at 30°C and electrodeposited at a constant current of -0.24A for 10 minutes. During the deposition process, it can be observed that a gray-black coating is gradually deposited on the cathode surface. After the deposition is completed, the electrode is taken out, carefully rinsed with anhydrous ethanol and deionized water, and dried to obtain a Ni3Sn2-NiSnO loaded thereon. x -3 composite catalyst material nickel foam electrode.

[0041] Example 5

[0042] This embodiment provides a nickel-tin alloy-oxide composite material Sn-NiSnO x The preparation method includes the following steps: take a piece of pretreated nickel foam (about 2 cm × 1 cm in length and width) as the electrodeposition substrate (working electrode), a platinum sheet as the counter electrode, and a Hg / HgO electrode as the reference electrode. The electrodeposition solution is prepared according to the following steps: 225.63 mg of SnCl2·2H2O is dissolved in 100 mL of deionized water, and 75.07 mg of glycine, 991.02 mg of potassium pyrophosphate and 360.36 mg of urea are added thereto as electrodeposition auxiliary agents. The electrodeposition solution is stirred at room temperature for 20 minutes. The above nickel foam electrode is placed in the electroplating solution at 30°C and electrodeposited at a constant current of -0.24A for 10 minutes. During the deposition process, it can be observed that a gray-black coating is gradually deposited on the cathode surface. After the deposition is completed, the electrode is taken out, carefully rinsed with anhydrous ethanol and deionized water, and dried to obtain a Sn-NiSnO loaded thereon. x Nickel foam electrode with composite catalyst material.

[0043] The properties of the final product were observed, such as Figure 2 、 Figure 3 、 Figure 4 shown.

[0044] Figure 2 The Ni3Sn2-NiSnO provided in this embodiment x Scanning electron microscope (SEM) images of the composite material, the sample is succulent-like. Figure 3 , we can see the uniform distribution of nickel and tin.

[0045] Figure 4 1 is an X-ray diffraction (XRD) pattern of the composite material provided in Examples 2-4 of the present invention, wherein the diffraction peaks shown correspond to the nickel-tin alloy phase and the oxide phase.

[0046] Application examples:

[0047] The NRR electrocatalytic performance test was carried out in a two-chamber H-type electrolytic cell separated by a Nafion 211 membrane. 0.1M KOH solution was used as the electrolyte. At room temperature, an electrochemical workstation (CHI760E) with a standard three-electrode system was used to perform electrochemical tests of all samples in 0.1M KOH. The working electrode was prepared by Ni3Sn2-NiSnO x The composite catalyst was made. Calibration was performed with reference to the reference and converted to reversible oxygen electrode (RHE) using the formula.

[0048] E (RHE) =E (Hg / HgO) +0.89

[0049] Before measuring the NRR, the electrolyte was bubbled with ultra-high purity N2 (99.999%) for 30 min. To explore the NRR activity, linear sweep voltammetry was performed from 0 V to 1.8 V at a scan rate of 5 mV / s.

[0050] The performance tests of the composite catalysts prepared in Examples 1-5 were carried out according to the above method. Figure 5 shown.

[0051] like Figure 5 As shown in a, the LSV polarization curve can not only calculate the overpotential, but also compare the LSV curves under N2 and Ar atmospheres. The difference in the LSV curves under the two atmospheres can be used to determine the potential range in which the nitrogen reduction reaction may occur and the NRR activity. It is obvious that the ammonia production can be tested using methods such as indophenol blue and Nessler's reagent and its corresponding Faradaic efficiency can be calculated (see Table 1 for specific data). Figure 5 It can be clearly seen in b and c that the Ni3Sn2-NiSnOx-1 and Ni3Sn2-NiSnO prepared according to the present invention x -2, Ni3Sn2-NiSnO x -3 composite materials compared to Ni-NiO x and Sn-NiSnO x The excellent nitrogen reduction performance may be attributed to the fact that the combination of NiSn alloy and oxide forms more interfacial active sites, which can promote electron transfer and optimize the activation path of N2, thereby further enhancing the reaction activity. Figure 5d, Ni3Sn2-NiSnO prepared in Example 3 x The excellent stability of the -2 composite material (see Table 2 for specific data) is attributed to the nickel foam substrate support that effectively prevents the material from collapsing during the nitrogen reaction.

[0052] Table 1 Catalytic performance test results of materials with different Ni and Sn ratios

[0053]

[0054]

[0055] Table 2 Ni3Sn2-NiSnO x -2 Catalytic stability test results of composite materials

[0056]

[0057] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific implementation method of the present invention and does not limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A nickel-tin alloy-oxide composite material Ni3Sn2-NiSnO x The preparation method is characterized in that The following steps are involved: S101, select SnCl2·2H2O as tin source, NiCl2 as nickel source, dissolve them in a solution containing electrodeposition auxiliary agent to prepare Ni-containing 2+ and Sn 2+ Electrodeposition solution; S102, applying a constant current to the nickel foam substrate as a cathode to perform electrodeposition, so that nickel and tin are co-deposited to form a nickel-tin alloy Ni3Sn2, which is partially oxidized during the deposition process to form a nickel-tin oxide phase NiSnO x ; S103, take out the deposited cathode and clean and dry it to obtain Ni3Sn2-NiSnO x Composite catalytic materials.

2. A nickel-tin alloy-oxide composite material Ni3Sn2-NiSnO according to claim 1 x The preparation method is characterized in that In step S101 , the electrodeposition auxiliary agents include glycine, potassium pyrophosphate, and urea. The molar ratio of glycine, potassium pyrophosphate, and urea is 1:3:

6. In the electrodeposition solution, the concentrations of glycine, potassium pyrophosphate, and urea are 0.01 mol / L, 0.03 mol / L, and 0.06 mol / L, respectively.

3. A nickel-tin alloy-oxide composite material Ni3Sn2-NiSnO according to claim 1 x The preparation method is characterized in that In step S101, the molar ratio of SnCl2·2H2O to NiCl2 is (0.5-2):1, and in the electrodeposition solution, Ni 2+ and Sn 2+ The concentrations are all 0.005-0.02mol / L.

4. A nickel-tin alloy-oxide composite material Ni3Sn2-NiSnO according to claim 2 x The preparation method is characterized in that In step S102, the electrodeposition time is maintained at 10 minutes.

5. A nickel-tin alloy-oxide composite material Ni3Sn2-NiSnO according to claim 2 x The preparation method is characterized in that In step S102, the temperature is maintained at 30°C during electrodeposition.

6. A nickel-tin alloy-oxide composite material Ni3Sn2-NiSnO according to claim 2 x The preparation method is characterized in that In step S102, the current during electrodeposition is -0.24A.

7. A nickel-tin alloy-oxide composite material Ni3Sn2-NiSnO x , characterized in that, The nickel-tin alloy-oxide composite material Ni3Sn2-NiSnO x It is prepared by the preparation method according to any one of claims 1 to 6.

8. A nickel-tin alloy-oxide composite material Ni3Sn2-NiSnO as claimed in claim 7 x The application is characterized in that The nickel-tin alloy-oxide composite material Ni3Sn2-NiSnO x Used in electrocatalytic ammonia synthesis reaction.

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