A2BC2 type ternary metal intermetallic electronic compound material and preparation method and application thereof

Abstract

The present invention belongs to the technical field of ternary metal intermetallic electronic compound materials, and discloses an A2BC2 type ternary metal intermetallic electronic compound material and a preparation method and application thereof, wherein the preparation method comprises: mixing components A and C in equal atomic ratios, and then smelting to form alloy AC; crushing the alloy AC, and then mixing it with component B in an atomic ratio of 1.8 to 2.2 to obtain a mixed powder; and annealing the mixed powder to obtain the A2BC2 type ternary metal intermetallic electronic compound material. The preparation method of the present invention is simple, has a low reaction temperature, a short preparation cycle, a low preparation cost, and obtains a material with better purity and crystallinity, and has extremely strong expansibility.

Description

Technical Field

[0001] The present invention relates to the technical field of ternary metal intermetallic electronic compound materials, and in particular to an A 2 BC 2 Type ternary metal intermetallic electronic compound material and its preparation method and application. Background Art

[0002] Electronic compounds are salts with a clear crystal structure in which a part of the electrons in the crystal lattice can exist independently in the crystallographic gaps as anions to balance the system charge without relying on specific elements (Science, 2003, 301, 607). The discovery of electronic compounds breaks through the three traditional cognitions of the existence of electrons in crystals (ionic bonds, metallic bonds and covalent bonds). Its anionic electrons are localized in the lattice gaps formed by cations and play the role of anions in the compound, playing the role of balancing the system charge and having independent electron orbits (Acc. Chem. Res., 2009, 42, 1564). In addition, the anionic electrons in electronic compounds occupy higher energy bands (through or close to the Fermi level), which means that electrons can be easily donated, that is, electronic compounds have extremely strong electron-donating ability (Science, 2003, 301, 626). Electronic compounds have many unique properties such as high electron concentration, low work function, non-transition metal magnetism, etc., which make them have broad application prospects in the fields of synthetic ammonia catalysis, rechargeable batteries, superconductors, organic light-emitting diodes (OLEDs) and spintronic devices. (Nano Lett., 2007, 7, 1138; Adv. Mater., 2007, 19, 3564; J. Am. Chem. Soc., 2017, 139, 615.; Angew. Chem. Int. Edit., 2019, 58, 825)

[0003] In recent years, high-throughput computational screening based on general material databases has begun to be used in the research of new electronic compounds, significantly accelerating the discovery of new electronic compound materials. 2 Prototype B, based on the 34,000 inorganic materials in the Materials Project universal database, searches for 2-D electronic compounds and finally successfully searches for Ca 2 N、Sr 2 N.Ba 2 N, Y 2 C.K 2 Cl, K 2 Be、Rb 2 Cl, Rb 2 Br, Li 2 F and Na2 Cl and a series of potential 2-D electronic compounds (Inorg.Chem., 2014, 53, 10347). In 2018, Lee A.Burton et al. from the University of Louvain in Belgium used Sr 5 P 3 The structure of is used as a prototype, combined with first-principles calculations, a high-throughput search was carried out on more than 60,000 compounds in the ICSD database, and 65 candidate electronic compounds and 4 known electronic compounds were screened (Chem. Mater., 2018, 30, 7521). At present, the number of components of the reported electronic compounds is mostly binary, and there are few reports on ternary electronic compounds. Although some computational work has attempted to find ternary electronic compounds, most of the ternary electronic compounds mentioned in existing studies are hypothetical compounds, which are not stable under normal conditions and cannot be synthesized and applied.

[0004] In 2019, the inventors combined the first principles and the Materials Project general database to conduct the first high-throughput screening of ternary inorganic electronic compounds, and finally identified three new thermodynamically stable electronic compounds Li 12 Mg 3 Si 4 、NaBa 2 O and Ca 5 Ga 2 N 4 (Phys. Rev. B, 2019, 99, 064104.). However, candidate materials are limited to existing general databases, and related work can only continuously search for existing compounds based on different screening conditions, making it difficult to jump to the vast space outside the database. Therefore, developing a preparation method for ternary intermetallic electronic compound materials is of great significance for exploring the new properties and expansion of ternary intermetallic electronic compound materials and their applications.

[0005] To this end, the present invention provides a 2 BC 2 Type ternary metal intermetallic electronic compound material and its preparation method and application. Summary of the invention

[0006] In order to solve the above-mentioned deficiencies in the prior art, the present invention provides a 2 BC 2 Type ternary metal intermetallic electronic compound material and its preparation method and application.

[0007] A kind of A of the present invention 2 BC 2 The ternary metal intermetallic electronic compound material and its preparation method and application are realized through the following technical solutions:

[0008] The first object of the present invention is to provide a 2 BC 2 The method for preparing a ternary metal intermetallic electronic compound material comprises the following steps:

[0009] Step 1, mixing metal A and metal C in equal atomic ratios, and then smelting to form alloy AC;

[0010] Step 2, crushing the alloy AC, and uniformly mixing it with metal C at an atomic ratio of 1.8 to 2.2 to obtain a mixed powder;

[0011] Step 3, annealing the mixed powder to obtain the A 2 BC 2 Type ternary intermetallic electronic compound materials;

[0012] Wherein, A is any one of La, Nd, Ca, Sc, Ti, Y, Zr, Hf, Ta and Ln;

[0013] B is any one of Li, Mg, Al, Sc, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Ru, Rh, Pd, Cd, In, Sn, Ln, Pt, Au, Yb and Pb;

[0014] C is any one of B, C, N, Al, Si, P, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Ru, Rh, Pd, In, Sn, Sb, Pt, Au, Tl, Pb and Bi.

[0015] Furthermore, the mixed powder is sealed in an argon atmosphere and then annealed.

[0016] Furthermore, the annealing treatment temperature is 100-3000° C., and the annealing time is 1-720 hours.

[0017] Furthermore, the smelting process is performed by arc melting.

[0018] The second object of the present invention is to provide a kind of A prepared by the above-mentioned preparation method 2 BC 2 Type ternary intermetallic electronic compound materials.

[0019] Furthermore, A 2 BC 2 The ternary metal intermetallic compound material has a P4 / mbm crystal structure and its molecular formula is A 2 BC 2 ;

[0020] Wherein, A is any one of La, Nd, Ca, Sc, Ti, Y, Zr, Hf, Ta and Ln;

[0021] B is any one of Li, Mg, Al, Sc, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Ru, Rh, Pd, Cd, In, Sn, Ln, Pt, Au, Yb and Pb;

[0022] C is any one of B, C, N, Al, Si, P, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Ru, Rh, Pd, In, Sn, Sb, Pt, Au, Tl, Pb and Bi.

[0023] Furthermore, its molecular formula is La 2 MgGe 2 ,La 2 Yb 2 、Nd 2 SSi 2 Any one of .

[0024] Furthermore, the A 2 BC 2 The form of the ternary metallic intermetallic compound material is any one of powder, bulk, and thin film, or a combination of two or more thereof.

[0025] Furthermore, the A 2 BC 2 The ternary metal intermetallic compound material is in the form of powder, and its particle size is 1 to 50 μm.

[0026] The third object of the present invention is to provide a 2 BC 2 Application of a ternary metal intermetallic electronic compound material in the preparation of a catalytic material, wherein the catalytic material is any one of a synthetic ammonia catalytic material, an ammonia decomposition catalytic material, a magnetic material and a HER catalytic material.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The preparation method of the present invention is simple, has a low reaction temperature, a short preparation cycle, a low preparation cost, and obtains materials with better purity and crystallinity, and has extremely strong scalability.

[0029] A of the present invention 2 BC 2The type ternary metal intermetallic electronic compound material has the characteristics of P4 / mbm space structure, and the structural gap of the electronic compound of the present invention has high-energy interstitial electrons, resulting in a low work function of the material and good electron supply ability, so that it also has many unique properties such as high electron concentration, low work function, non-transition metal magnetism, etc., and can be well applied in synthetic ammonia catalytic materials, ammonia decomposition catalytic materials, magnetic materials and HER catalytic materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A in Example 1 2 BC 2 (P4 / mbm) type ternary intermetallic electronic compound material La 2 MgGe 2 XRD pattern of

[0031] Figure 2 A in Example 2 2 BC 2 (P4 / mbm) type ternary intermetallic electronic compound material La 2 Yb 2 XRD pattern of

[0032] Figure 3 A in Example 3 2 BC 2 (P4 / mbm) type ternary intermetallic electronic compound material Nd 2 SSi 2 XRD pattern of

[0033] Figure 4 A of Example 2 and Example 3 2 BC 2 The catalytic activity of type ternary metal intermetallic compound materials as catalysts for ammonia synthesis. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0035] The present invention provides a 2 BC 2 Type ternary metal intermetallic electronic compound material, and its preparation method is as follows:

[0036] Step 1: Follow A 2 BC 2 According to the stoichiometric ratio in the molecular formula, weigh the corresponding masses of A, B and C and set aside;

[0037] It should be noted that the present invention does not limit the specific elements of the ternary metal intermetallic compound material, as long as it can form a2 BC 2 The invention relates to an electronic compound of a molecular formula of type 4 and a P4 / mbm crystal structure. A and B are both metal elements, and optionally, A can be selected from any one of La, Nd, Ca, Sc, Ti, Y, Zr, Hf, Ta and Ln; B can be selected from any one of Li, Mg, Al, Sc, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Ru, Rh, Pd, Cd, In, Sn, Ln, Pt, Au, Yb and Pb; C can be selected from any one of B, C, N, Al, Si, P, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Ru, Rh, Pd, In, Sn, Sb, Pt, Au, Tl, Pb and Bi.

[0038] Step 2, melting the weighed components A and C to form alloy AC;

[0039] It should be noted that the present invention does not limit the specific process of melting A and C into alloy AC, as long as the A element and the C element can be fully mixed and uniformly formed to form an alloy AC with uniform composition. The present invention preferably adopts arc melting method for melting, and its specific process is as follows:

[0040] The weighed bulk elements are placed in a copper crucible in a melting furnace, and then arc melting is performed in an argon atmosphere. During arc melting, the current is adjusted to keep the sample in a molten state for 3 to 5 seconds; the metal ingot is turned over and the melting is repeated 1 to 10 times. The specific size of the current is not limited in the present invention, and can be adjusted according to the actual selected materials A and B, as long as the sample can be in a molten state.

[0041] Step 3, crushing alloy AC and mixing it evenly with the weighed metal C to obtain a mixed powder;

[0042] It should be noted that the present invention does not limit the specific method of pulverizing the alloy AC, as long as the alloy AC can be pulverized into micrometer level. Preferably, the pulverization is performed by manually grinding in a glove box for 20 to 40 minutes.

[0043] Step 4, annealing the mixed powder to obtain the A 2 BC 2 Type ternary intermetallic electronic compound materials;

[0044] It should be noted that the present invention does not limit the specific annealing temperature and annealing time, which can be adjusted according to the actual selected materials of A, B, and C to achieve the purpose of forming a compound of the three elements and making the sample uniform and having a good purity. Optionally, the present invention anneals at 100 to 3000° C. for 1 to 720 hours. Preferably, the annealing temperature is 900 to 1100° C.

[0045] Example 1

[0046] This embodiment provides a 2 BC 2 Type ternary metal intermetallic electronic compound material, whose molecular formula is La 2 MgGe 2 , and its preparation method is as follows:

[0047] The metal blocks of La and Ge were weighed and mixed according to the atomic ratio of La:Ge=1:1 using an electronic balance, and then the mixed raw materials were placed in a micro-metal melting furnace; before melting, the melting furnace chamber was flushed with Ar gas and repeatedly evacuated 3 times using a molecular pump, and after the last filling of Ar gas, Ti particles were used for deoxidation; then, the weighed metal blocks of La and Ge were placed in a copper crucible of the melting furnace, and arc melting was performed in an argon atmosphere, and the current was adjusted during arc melting so that the sample was in a molten state and kept for 5 seconds, then turned over and continued to melt so that the molten state was kept for 5 seconds, and the melting was repeated 5 times to ensure uniform melting of the alloy, and the sample was taken out after cooling. The cooled LaGe alloy sample was ground in a mortar to obtain a powder sample of the LaGe alloy.

[0048] The LaGe alloy and Mg element were weighed and mixed in an atomic ratio of 2:1. The mixed powder was placed in a stainless steel tube, and the stainless steel tube was sealed in an arc melting furnace under an argon atmosphere. The stainless steel tube was kept at 1000°C for 30 hours to obtain the final LaGe alloy. 2 MgGe 2 Compound samples.

[0049] Finally, the sample was taken out and ground in a stainless steel tube in the glove box, and the obtained powder was directly stored in the glove box for subsequent characterization.

[0050] Example 2

[0051] This embodiment provides a 2 BC 2 Type ternary metal intermetallic electronic compound material, whose molecular formula is La 2 Yb 2 , and its preparation method is as follows:

[0052] Use an electronic balance to weigh La and Ge metal blocks according to the atomic ratio of La:Ge = 1:1 and mix them. Then put the mixed raw materials into a micro metal melting furnace. Before melting, flush the melting furnace chamber with Ar gas and repeatedly evacuate the chamber with a molecular pump for 3 times (to a vacuum degree of 10 -5 Pa), and after the last filling of Ar gas (to a pressure of -0.2MPa), Ti particles were used for deoxidation; then, the weighed La and Ge metal blocks were placed in a copper crucible of a melting furnace, arc-melted in an argon atmosphere, and the current was stabilized at 150A for 15 seconds after arcing. After cooling, the melting was continued, and the melting was repeated 5 times to ensure uniform melting of the alloy, and the sample was taken out after cooling. The cooled LaGe alloy sample was ground in a mortar to obtain a powder sample of the LaGe alloy.

[0053] The LaGe alloy and Yb element were weighed and mixed in an atomic ratio of 2:1. The mixed powder was placed in a stainless steel tube, and the stainless steel tube was sealed in an arc melting furnace under an argon atmosphere. The stainless steel tube was kept at 1000°C for 30 hours to obtain the final LaGe alloy. 2 Yb 2 Compound samples.

[0054] Finally, the sample was taken out and ground in a stainless steel tube in the glove box, and the obtained powder was directly stored in the glove box for subsequent characterization.

[0055] Example 3

[0056] This embodiment provides a 2 BC 2 Type ternary metal intermetallic electronic compound material, its molecular formula is Nd 2 SSi 2 , and its preparation method is as follows:

[0057] In this embodiment, considering that the melting points of Nd, Sc and Si are relatively high, an electronic balance is directly used to weigh Nd metal blocks, Sc metal blocks and Si sheets according to the atomic ratio Nd:Sc:Si=2:1:2, and then the mixed raw materials are placed in a micro-metal melting furnace; before melting, the melting furnace chamber is flushed with Ar gas and repeatedly evacuated 3 times with a molecular pump, and after the last filling of Ar gas operation is completed, Ti particles are used for deoxidation; then, the weighed Nd metal blocks, Sc metal blocks and Si sheets are placed in a copper crucible of the melting furnace, and arc melting is performed in an argon atmosphere: after arcing, the current is stabilized at 150A for 15 seconds, and the melting is continued after cooling, and the melting is repeated 6 times to ensure uniform melting of the alloy, and the sample is taken out after cooling. The cooled LaGe alloy sample is ground in a mortar to obtain a powder sample of the LaGe alloy.

[0058] The cooled sample was sealed in a vacuum quartz tube in a glove box and then kept at 1000 °C in a box furnace for 14 days to obtain the final Nd 2 SSi 2 Compound samples.

[0059] Finally, the sample was taken out and ground in a stainless steel tube in the glove box, and the obtained powder was directly stored in the glove box for subsequent characterization.

[0060] Experimental Section

[0061] (I) XRD test

[0062] The present invention is respectively prepared in Examples 1-3 A 2 BC 2 The XRD test results of the ternary metal intermetallic compound materials are as follows: Figure 1-Figure 3 As shown, Figure 1 A in Example 1 2 BC 2 (P4 / mbm) type ternary intermetallic electronic compound material La 2 MgGe 2 XRD pattern of Figure 2 A in Example 2 2 BC 2 (P4 / mbm) type ternary intermetallic electronic compound material La 2 Yb 2 XRD pattern of Figure 3 A in Example 3 2 BC 2 (P4 / mbm) type ternary intermetallic electronic compound material Nd 2 SSi 2 XRD pattern of .

[0063] Depend on Figure 1-Figure 3 It can be seen that: A prepared in Examples 1-3 of the present invention 2 BC 2 The samples of this type of ternary metal intermetallic compound materials have good purity and good crystallinity.

[0064] (II) Catalytic performance test

[0065] The present invention is based on A of Example 2 and Example 3 2 BC 2 The ternary metal intermetallic electronic compound material was used as a catalyst to test the catalytic activity in the synthesis of ammonia. The test method was as follows: the metal Ru was loaded on the A of Example 2 and Example 3 by chemical vapor deposition. 2 BC 2The catalysts with different metal Ru loadings were prepared on the ternary metal intermetallic compound materials, namely 1.4% Ru / Nd 2 SSi 2 、2.8%Ru / Nd 2 SSi 2 、1.4%Ru / La 2 SSi 2 , and 3%Ru / La 2 Yb 2 , where the percentage content indicates A 2 BC 2 The loading amount of metal Ru on the ternary metal intermetallic compound material. 0.1g of the catalyst was placed in a microreactor device to test its ammonia synthesis activity. The reaction temperature was 400℃, N 2 and H 2 The gas flow rate is 15:45 mL / min. The ammonia in the tail gas is absorbed by dilute sulfuric acid solution, and the ammonium radical production in the tail gas is detected by ion chromatography to further obtain the synthetic ammonia activity of the catalyst, and the test results are as follows: Figure 4 shown.

[0066] Depend on Figure 4 It can be seen that: Ru / Nd 2 SSi 2 andRu / La 2 Yb 2 Both catalysts have the activity of synthesizing ammonia, and Ru / Nd 2 SSi 2 The activity is significantly better than that of Ru / La 2 Yb 2 ;Ru / Nd 2 SSi 2 The activity at low loading has obvious advantages, indicating that the A prepared by the present invention 2 BC 2 The ternary intermetallic electronic compound material can be used as a catalytic material for synthesizing ammonia, and can be applied to ammonia decomposition catalytic materials, magnetic materials, HER catalytic materials, etc.

[0067] Obviously, the above embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Claims

1. An application of an A2BC2 type ternary metal intermetallic electronic compound material in the preparation of ammonia synthesis catalytic material, characterized in that: The A2BC2 type ternary intermetallic electronic compound material has a P4 / mbm type crystal structure, and its molecular formula is A2BC2, and the A2BC2 type ternary intermetallic electronic compound material is prepared by the following steps: Step 1, mixing component A and component C in an equal atomic ratio, and then melting to form alloy AC; Step 2, crushing the alloy AC, and uniformly mixing it with component B at an atomic ratio of 1.8 to 2.2 to obtain a mixed powder; Step 3, annealing the mixed powder to obtain the A2BC2 type ternary metal intermetallic electronic compound material; Wherein, component A is La or Nd; Component B is any one of Mg, Sc and Yb; Component C is Si or Ge; The A2BC2 type ternary metal intermetallic electronic compound material is made into a synthetic ammonia catalytic material by the following steps: The Ru metal is loaded on the A2BC2 type ternary metal intermetallic electronic compound material by using chemical vapor deposition technology; The loading amount of the metal Ru on the A2BC2 type ternary metal intermetallic electronic compound material is any one of 1.4%, 2.8% and 3%.

2. The use according to claim 1, characterized in that The mixed powder is sealed in an argon atmosphere and then annealed.

3. The use according to claim 1, characterized in that The annealing treatment temperature is 100-3000° C., and the annealing time is 1-720 hours.

4. The use according to claim 1, characterized in that The smelting process is performed by arc melting.

5. The A2BC2 type ternary intermetallic electronic compound material according to claim 1, characterized in that: Its molecular formula is any one of La2MgGe2, La2YbGe2, and Nd2ScSi2.

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