Preparation method of nano-porous cu2tisn heusler alloy and catalytic application thereof

Abstract

The present application relates to a kind of preparation method of nano-porous Cu2TiSn hasler alloy and its catalytic reduction reaction application in solution.By the chemical or electrochemical corrosion of alloy strip, phase transformation and porous structure construction of alloy are realized, and nano-porous ternary intermetallic compound material is obtained.The material has catalytic activity to reduction reaction in solution, can promote the chemical reduction reaction of methylene blue solution and the electrocatalytic reduction of nitrate to ammonia reaction.Therefore, the hasler alloy involved in the present application is simple to prepare, and has outstanding catalytic activity, with good application prospect.

Description

Technical Field

[0001] This invention relates to a method for preparing nanoporous Cu2TiSn Hassler alloy and its catalytic application, belonging to the field of advanced functional materials. Background Technology

[0002] Intermetallic compounds are a class of materials with ordered metallic superlattice structures formed by intermetallic interactions in specific atomic ratios, playing unique roles in high-temperature, electromagnetic, and superconducting fields. In recent years, research on these materials in the field of energy catalysis has attracted considerable attention. By partially or completely replacing the noble metal Pt, they have achieved remarkable results in oxygen reduction, carbon dioxide reduction, and organocatalysis (J. Mater. Chem. A 2020, 8, 15620-15645; J. Mater. Chem. A 2020, 8, 8195-8217; Adv. Mater. 2021, 2005988.). Intermetallic compounds regulate the d-orbital electronic structure and lattice geometry of metals through intermetallic interactions, exhibiting catalytic activity far exceeding that of elemental metals. Simultaneously, the highly ordered surface atoms exhibit a tendency for species adsorption and surface dynamic processes, thereby improving the selectivity of catalytic products. However, most current intermetallic compound materials are predominantly binary in phase diagrams and typically contain noble metals. Multi-element intermetallic compound materials offer a broader scope for regulating material properties, especially non-noble metal intermetallic compounds, which represent a promising area for the development of catalytic materials.

[0003] Hassler alloys are ternary or multi-metal intermetallic compounds, typically having X2YZ or X2YZ components. x Z' 1-x Composed of metallic elements, these materials, due to the confined d electrons and the interactions between unconfined s or p electrons, possess relatively complex band structures and exhibit thermoelectric and magnetic physical effects. They are considered "ferromagnetic alloys without ferromagnetic elements" and show promising applications in spintronics, thermoelectrics, and shape memory materials (ACS Omega 2017, 2, 1, 147-153). Theoretically, these alloys have a wide variety of combinations, and intermetallic compounds, due to the interactions between atoms, can easily control the electronic structure and surface atomic arrangement, showing potential application value in catalysis. Kojima et al. combined Co₂FeGa x Ge 1-x CoMn x Fe 1-xGe-Hassler alloys have been used in the hydrogenation of propyne to achieve near 100% conversion and selectivity (Sci. Adv. 2018, 4, eaat6063). However, these materials are difficult to prepare. The three or more elements often form binary metal alloys, making it difficult to form intermetallic compounds according to the predetermined target. A long, high-temperature annealing process is usually required for preparation. Subsequent grinding processes are needed to pulverize the materials into powder; therefore, the particle size of these intermetallic compounds is typically in the micrometer scale, and the specific surface area is usually small.

[0004] Therefore, developing new methods for preparing Hassler alloy functional materials and exploring their applications is of great scientific significance and practical value. Summary of the Invention

[0005] To address the problems of traditional Hassler alloys in terms of preparation efficiency and reaction conditions, this invention discloses a method for preparing nanoporous Cu2TiSn and its catalytic application.

[0006] A Cu2TiSn Hassler alloy material is characterized by having an intermetallic compound phase formed by dealloying and a nanoporous structure.

[0007] A method for preparing a nanoporous Cu2TiSn Hassler alloy material includes the following steps:

[0008] S1, Precursor alloy melting: according to (Cu2TiSn) x M 100-4x The elemental composition ratio (M is Al or Zn) is used to melt the elemental metal to obtain an alloy ingot;

[0009] S2, Alloy Strip Spinning: The alloy molten in S1 is spun into a strip to obtain an alloy strip;

[0010] S3, Dealloying: Chemical or electrochemical corrosion is performed on the alloy strips obtained in S2 to obtain Cu2TiSn Hasler alloy material.

[0011] Furthermore, in S1, x is 2-10;

[0012] Preferably, in S1, x is 3-5.

[0013] Furthermore, in S2, the belt-spinning speed is 2000-5000 rpm.

[0014] Furthermore, in S3, chemical corrosion involves placing the strip in a strong alkaline solution until the reaction is complete.

[0015] Furthermore, in chemical corrosion, the concentration of the strong alkaline solution is 0.5–2 M, and the reaction time is 4–20 hours.

[0016] Preferably, in the chemical corrosion process, the concentration of the strong alkaline solution is 1M, and the reaction time is 8-15 hours.

[0017] Furthermore, in S3, electrochemical corrosion involves placing the electrode in a strong alkaline solution and selectively corroding it using a three-electrode electrochemical cyclic voltammetry method.

[0018] Furthermore, corrosion was carried out using a three-electrode electrochemical cyclic voltammetry method, with a strong alkaline solution concentration of 1M, a potential range of -1.0 to -0.1V vs HgO / Hg, and 50 to 1000 cyclic voltammetry corrosion cycles.

[0019] Furthermore, corrosion was carried out using a three-electrode electrochemical cyclic voltammetry method, with a potential range of -0.8 to -0.3 V vs HgO / Hg and a cyclic voltammetry corrosion cycle number of 100 to 800 cycles.

[0020] Furthermore, the strong alkaline solution is an aqueous solution of sodium hydroxide or potassium hydroxide.

[0021] An application of a nanoporous Cu2TiSn Hassler alloy material is for catalyzing reduction reactions in solution.

[0022] Furthermore, this material can be used to catalyze the chemical reduction reaction of methylene blue in solution, with methylene blue as the substrate and sodium borohydride as the reducing agent.

[0023] Furthermore, in the methylene blue reduction reaction catalyzed by this material, the reaction environment is an aqueous solution, and the ratio of substrate to reducing agent is 1:20 to 1:150.

[0024] Furthermore, in the electrochemical nitrate reduction reaction to ammonia in solution catalyzed by this material, the substrate is nitrate and the product is ammonium salt.

[0025] Furthermore, in the ammonia production reaction catalyzed by the material in the electroreduction of nitrate in the solution, the solution is neutral and the nitrate concentration is 0.01-0.15M.

[0026] The principle behind this preparation method is dealloying-induced atomic rearrangement. The CuTiSnM (M is Al or Zn) master alloy contains multiple binary intermetallic compound phases and metallic Al (or Zn) phases (see attached diagram). Figure 2 During the reaction, the more reactive metallic phase Al (or Zn) is selectively corroded. Subsequently, the binary intermetallic compound containing the reactive metal Al (or Zn) undergoes dealloying corrosion. The atomic movement and energy transfer resulting from dealloying induce the rearrangement of the remaining atoms into a ternary intermetallic compound phase, forming the Cu2TiSn Hassler alloy phase. In the chemical or electrochemical corrosion process, the selective corrosion of the more reactive metallic phase creates a nanoporous structure, resulting in a larger exposed active surface area in the material.

[0027] By adopting the above technical solution, the beneficial effects of the present invention are as follows:

[0028] First, the preparation of nanoporous Cu2TiSn Hassler alloy materials via dealloying reaction exhibits a dealloying-induced mechanism significantly different from traditional methods. Traditional methods for preparing Hassler alloys, such as melt and long-term annealing (J. Mater. Chem. A2023, 11, 2302-2313.), high-energy ball milling (J. Mater. Res. 1997, 12, 1492-1500.), and electrochemical deposition (J. Magn. Magn. Mater. 2021, 539, 168355.), involve the formation of a ternary lattice arrangement driven by external energy. In contrast, the method described in this patent induces the spontaneous formation of a ternary intermetallic compound phase, i.e., Hassler alloy, at room temperature. Furthermore, in the preparation of porous materials using the dealloying method, the precursor alloy typically already contains the target phase and active components. Removing the active components yields the porous target phase without a phase transformation process (EnergyChem 2022, 4, 100069.). This patented method eliminates the need for prolonged heating and annealing, resulting in rapid formation of the target phase, low cost, and suitability for mass production. Simultaneously, it directly yields materials with nanoporous structures, fully exposing the active surface area and providing opportunities for the application of Hasler alloys as functional materials. Therefore, this patented method, which induces the formation of Hasler alloys while simultaneously creating porous structures, is significantly different from traditional methods.

[0029] Secondly, the nanoporous Cu2TiSn Hassler alloy material exhibits outstanding catalytic performance, demonstrating the practical value of Hassler alloy materials in reduction catalysis reactions in solution. Due to the clear biotoxicity of methylene blue, the treatment of excess methylene blue in the environment has become an important issue for environmental science and human health (J. Hazard. Mater. 2018, 344, 210-219; Catal. Commun. 2017, 90, 75-78.). Chemical reduction is an effective method for treating methylene blue, and noble metal catalysts such as Au, Ag, and Pd have attracted research attention due to their excellent catalytic performance (Rev. Chem. Engin. 2019, 36, DOI:10.1515 / revce-2018-0047.). This patent develops non-noble metal intermetallic compound catalytic materials that can achieve rapid and efficient reduction processes, realizing catalytic reduction reactions in solution environments and expanding the application of gas-phase catalysis (Sci. Adv. 2018, 4, eaat6063.). Meanwhile, nitrates are common pollutants in industrial and agricultural wastewater and groundwater. Converting nitrates into ammonia is a feasible green ammonia production route, and related research is rapidly developing (Coordin. Chem. Rev. 2024, 506, 215723). This patent develops a non-precious metal intermetallic compound catalytic material that enables rapid and efficient reduction processes, achieving chemical and electrocatalytic reduction reactions in solution environments. The catalyst's high activity and low cost make it promising for applications in wastewater treatment and value-added conversion.

[0030] Therefore, the preparation of nanoporous Hassler alloys and their application in catalytic reduction reactions of the present invention have significant novelty, inventiveness and practicality. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the preparation process of nanoporous Cu2TiSn Hassler alloy;

[0032] Figure 2 It is (Cu2TiSn)3Al 88 XRD pattern of the alloy;

[0033] Figure 3 It is (Cu2TiSn)3Al 88 XRD pattern of nanoporous Cu2TiSn Hassler alloy prepared by electrochemical corrosion;

[0034] Figure 4 It is (Cu2TiSn)5Al 80 XRD pattern of nanoporous Cu2TiSn Hassler alloy prepared by chemical etching;

[0035] Figure 5It is (Cu2TiSn)5Al 80 Microstructure of nanoporous Cu2TiSn Hassler alloy prepared by chemical etching;

[0036] Figure 6 It is (Cu2TiSn)5Al 80 XRD pattern of nanoporous Cu2TiSn Hassler alloy prepared by electrochemical corrosion;

[0037] Figure 7 It is (Cu2TiSn)5Al 80 Microstructure of nanoporous Cu2TiSn Hassler alloy prepared by electrochemical corrosion;

[0038] Figure 8 It is (Cu2TiSn)5Zn 80 XRD pattern of the alloy;

[0039] Figure 9 It is (Cu2TiSn)5Zn 80 XRD pattern of nanoporous Cu2TiSn Hassler alloy prepared by chemical etching;

[0040] Figure 10 This is a spectrum of solution changes during the reduction of methylene blue without the addition of a catalyst;

[0041] Figure 11 This is a solution spectral change diagram of the reduction reaction of methylene blue catalyzed by nanoporous Cu2TiSn Hassler alloy;

[0042] Figure 12 This is a repeatability test of the electrocatalytic nitrate reduction to ammonia production reaction of nanoporous Cu2TiSn Hassler alloy. Detailed Implementation

[0043] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the invention will be further described below in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention; that is, the described embodiments are only a part of the embodiments of this invention, and not all of them.

[0044] Example 1: Chemical etching preparation of nanoporous Cu2TiSn Hassler alloy

[0045] According to the preparation process (as attached) Figure 1 As shown), high-purity Cu, Sn, Ti, and Al are mixed according to the formula (Cu₂TiSn)₃Al. 88The composition ratio was uniformly melted in a vacuum arc furnace to obtain a master alloy ingot; the master alloy was then spun into a strip at a rate of 4 k rpm in a strip spinning machine. Dealloying was performed electrochemically in 1 M KOH solution, using the alloy strip as the working electrode, an Hg / HgO electrode as the reference electrode, and a graphite rod as the counter electrode. The electrochemical cyclic voltammetry scan range was -0.8 to -0.3 V vsHg / HgO, the scan rate was 0.1 V / s, and the number of scans was 150. Al metal was corroded, yielding a black product.

[0046] XRD tests show that (Cu2TiSn)3Al 88 The alloy contains metallic Al phase, AlCu2 phase, AlTi / AlTi2 phase, and Sn phase, but does not contain Cu2TiSn Hassler alloy phase (see attached). Figure 2 (As shown). After corrosion, the resulting product is a Cu2TiSn Hassler alloy phase (as shown in the attached image). Figure 3 As shown in the figure, this indicates that during the corrosion process, metal atoms rearranged to achieve a phase change, forming a ternary intermetallic compound, Hassler alloy.

[0047] Example 2: Chemical and electrochemical corrosion preparation of nanoporous Cu2TiSn Hassler alloy

[0048] High-purity Cu, Sn, Ti, and Al are mixed according to the formula (Cu₂TiSn)₅Al. 80 The composition ratio is uniformly melted in a vacuum arc furnace to obtain a master alloy ingot; the master alloy is then made into a strip by spinning at a rate of 4k rpm in a strip spinning machine.

[0049] Dealloying was performed using a chemical method. The resulting strips were reacted in a sufficient amount of 1M NaOH solution for 12 hours, resulting in the corrosion of Al metal and the production of a black product. XRD analysis showed that the product obtained after corrosion was a Cu2TiSn Hassler alloy phase (see attached). Figure 4 As shown in the figure, this indicates that the metal atoms underwent a phase change through rearrangement during corrosion, forming a ternary intermetallic compound, Hassler alloy. Scanning electron microscopy revealed that the obtained material exhibits a nanoscale porous structure (as shown in the attached figure). Figure 5 As shown in the figure, the formation of the nanoporous structure was confirmed.

[0050] Dealloying was performed electrochemically in 1M KOH solution, using the aforementioned alloy strip as the working electrode, an Hg / HgO electrode as the reference electrode, and a graphite rod as the counter electrode. The electrochemical cyclic voltammetry scan ranged from -0.8 to -0.3 V vs Hg / HgO, with a scan rate of 0.1 V / s and 150 scan cycles. Al metal was corroded, yielding a black product.

[0051] XRD analysis showed that the product obtained after corrosion was Cu2TiSn Hassler alloy (as shown in the attached image). Figure 6 As shown in the figure, this indicates that the metal atoms underwent a phase change through rearrangement during corrosion, forming a ternary intermetallic compound, Hassler alloy. Scanning electron microscopy revealed that the obtained material exhibits a nanoscale porous structure of stacked nanoparticles (as shown in the attached figure). Figure 7 As shown in the figure, the formation of the nanoporous structure was confirmed.

[0052] Example 3: Chemical etching preparation of nanoporous Cu2TiSn Hassler alloy

[0053] High-purity Cu, Sn, Ti, and Zn are mixed in the order (Cu₂TiSn)₅Zn 80 The composition ratio was uniformly melted in a vacuum arc furnace to obtain a master alloy ingot; the master alloy was then spun into strips at a rate of 4 k rpm in a strip spinning machine. The resulting strips were then dealloyed using a chemical method, reacting in a sufficient amount of 1 M NaOH solution for 12 hours, where the Zn metal was corroded to obtain a black product.

[0054] XRD test (as attached) Figure 8 As shown, (Cu2TiSn)5Zn 80 The alloy contains metallic Sn, CuZn5, and Ti phases, but not the Cu2TiSn Hassler alloy phase. After corrosion, the resulting product is a Cu2TiSn Hassler alloy (see attached). Figure 9 As shown in the figure, this indicates that during the corrosion process, metal atoms rearranged to achieve a phase change, forming a ternary intermetallic compound, Hassler alloy.

[0055] Example 4: Reduction of methylene blue catalyzed by nanoporous Cu2TiSn Hassler alloy

[0056] Mix 1 mL of methylene blue solution (0.10 mM) with 1 mL of sodium borohydride solution (10 mM) until homogeneous; the solution turns blue. Add 10 μL of aqueous dispersion of nanoporous Cu2TiSn material (1 mg / mL) and stir until homogeneous; the solution quickly decolorizes.

[0057] The changes in the solution spectrum were recorded using a UV-Vis spectrophotometer. The solution without a catalyst did not fade (as shown in the attached image). Figure 10 As shown in the attached image), after the catalyst was added, the methylene blue solution reacted and decolorized rapidly (as shown in the attached image). Figure 11 As shown in the figure, this indicates that the catalyst has significant catalytic reduction activity.

[0058] Example 5: Electrocatalytic reduction of nitrate to ammonia using nanoporous Cu2TiSn Hassler alloy

[0059] Weigh out the nanoporous Cu2TiSn material to prepare an ethanol dispersion, and take the dispersion at a ratio of 0.4 mg / cm³. -2 The loading was coated with carbon paper. Using the carbon paper electrode as the working electrode, a mixed solution of 0.1M K2SO4 and 0.1M KNO3 as the electrolyte, an Ag / AgCl electrode as the reference electrode, and a platinum sheet as the counter electrode, a constant potential of -1.4V vs. RHE was applied to carry out the nitrate reduction to ammonia reaction, and the experiment was repeated.

[0060] The amount of ammonia was determined by the indophenol blue colorimetric method, and the ammonia production rate (YR) and Faraday efficiency (FE) were calculated (see attached). Figure 12 (As shown). At a fixed potential, the ammonia production rate reaches 10 mg / h. -1 mg cat -1 The Faraday efficiency reached 75%, indicating that the material has the activity of catalyzing the reduction of nitrate to ammonia, and the electrocatalytic process is reproducible.

[0061] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A Cu2TiSn Hassler alloy material, characterized in that, The material possesses an intermetallic compound phase formed by dealloying and a nanoporous structure. The preparation method of the material includes the following steps: S1, Precursor alloy melting: according to (Cu2TiSn) x M 100-4x The elemental composition ratio is determined by melting the elemental metal to obtain an alloy ingot, where M is Al or Zn and x is 2-10. S2, Alloy Strip Spinning: The alloy melted in S1 is spun into a strip at a speed of 2000-5000 rpm to obtain an alloy strip; S3, Dealloying: Chemical or electrochemical corrosion is performed on the alloy strips obtained in S2 to obtain Cu2TiSn Hasler alloy material.

2. The Cu2TiSn Hassler alloy material according to claim 1, characterized in that, In S3, chemical or electrochemical corrosion is carried out in a strong alkaline solution.

3. The Cu2TiSn Hassler alloy material according to claim 2, characterized in that, In S3, the concentration of the strong alkaline solution is 0.5–2 M, and the chemical corrosion reaction time is 4–20 hours.

4. The Cu2TiSn Hassler alloy material according to claim 2, characterized in that, In S3, corrosion is carried out by three-electrode electrochemical cyclic voltammetry. The concentration of the strong alkali solution is 1 M, the potential range is -1.0 to -0.1 V vs HgO / Hg, and the number of cyclic voltammetry corrosion cycles is 50 to 1000.

5. The application of the Cu2TiSn Hassler alloy material according to claim 1 in catalysis, characterized in that, The material is used to catalyze reduction reactions in solutions.

6. The application of the Cu2TiSn Hassler alloy material according to claim 5 in catalysis, characterized in that, The application is the chemical catalysis of the reduction reaction of methylene blue in solution.

7. The application of the Cu2TiSn Hassler alloy material according to claim 5 in catalysis, characterized in that, The application is the electrocatalytic reduction of nitrates in solution to produce ammonia.

8. The application of the Cu2TiSn Hassler alloy material according to claim 6 in catalysis, characterized in that, In the chemical catalytic reduction reaction of methylene blue in solution, the substrate is methylene blue and the reducing agent is sodium borohydride.

9. The application of the Cu2TiSn Hassler alloy material according to claim 7 in catalysis, characterized in that, In the electrocatalytic reduction of nitrates to ammonia in solution, the substrate is nitrate and the product is ammonium salt.

10. The application of the Cu2TiSn Hassler alloy material according to claim 9 in catalysis, characterized in that, In the electrocatalytic reduction of nitrate to ammonia reaction, the solution is neutral and the nitrate concentration is 0.01-0.15M.

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