Method for constructing nano material based on multi-element nitrite eutectic salt system

Abstract

The invention discloses a method for constructing a nano material based on a multi-element nitrite eutectic salt system, and belongs to the technical field of nano material synthesis, and the method specifically comprises the following steps: putting sodium nitrite and potassium nitrite into an air muffle furnace, and preheating into molten salt; the method comprises the following steps: dissolving at least one metal salt in a solvent, mixing and reacting with molten salt, preserving heat, cooling and cleaning to obtain a nano material, particularly a nano main body material or a material in which at least one rare earth element is loaded in a bulk phase of the nano main body material in a monatomic form, and the nano main body material is a nano metal or oxide nano material; by controlling the mixing ratio of sodium nitrite to potassium nitrite, the heat preservation temperatures of different metal salts are adjusted, so that different nano materials are synthesized. According to the method, the nano material is synthesized from different metal salt precursors at low temperature in one step, and the method has the advantages that the different metal salt precursors are rapidly and simultaneously nucleated, the size of a target product is controllable, and a readily oxidizable material phase can be directly synthesized, and has important significance on potential application of the method in various fields.

Description

Technical Field

[0001] This invention belongs to the field of nanomaterial synthesis technology, specifically relating to a method for constructing nanomaterials based on a multi-component nitrite eutectic salt system. Background Technology

[0002] Nanomaterials encompass a range of emerging materials with microscopic dimensions at the nanoscale. Due to their extremely high surface atomic ratio and unique band structures at the nanoscale, nanomaterials often exhibit highly specialized physicochemical effects, including thermal, magnetic, optical, and catalytic properties. Therefore, nanomaterials are widely used in the electronics and computer industries, novel chemical processes, environmental protection, medicine, and many everyday applications. However, due to the unique and diverse structures of nanomaterials, current research remains limited by the complexity of their construction processes, low purity, and unclear synthesis mechanisms. Therefore, researching novel nanomaterial construction methods that are versatile, easy to operate, and produce controllable results is of great significance.

[0003] Molten salt synthesis, as a non-aqueous nanomaterial synthesis method, boasts advantages such as simple operation, high product purity, wide applicability, and diverse and controllable synthesis parameters, providing a novel research platform distinct from traditional nanomaterial synthesis methods. Molten salt synthesis typically uses several eutectic salts as high-temperature solvents, combining multiple steps such as precipitation-calcination in traditional methods into a single step. By directly introducing reactant precursors and initiators into the system, various nanostructures can be calcined. Furthermore, by adjusting various molten salt components and introducing reaction aids, the reaction rate, chemical environment, mass transfer behavior, and reactant compatibility during nanomaterial formation can be controlled, thereby achieving the construction of a wide range of tunable nanocrystalline structures and providing important insights for nanomaterial synthesis.

[0004] Current molten salt synthesis techniques for nanocrystals often employ sodium chloride-potassium chloride molten salt systems with high operating temperatures or nitrate molten salt systems with limited nanocrystal nucleation rates. The high operating temperatures of these molten salt systems, or the use of easily explosive components, increase the operational difficulty in practical applications. Furthermore, the reaction mechanisms of these molten salt systems are not yet fully understood, and the means of controlling the chemical reactions are very limited, restricting their application in the synthesis of multi-component nanocrystals. Summary of the Invention

[0005] To address the problems existing in the synthesis of nanomaterials using existing molten salt systems, this invention provides a method for constructing nanomaterials based on a multi-component nitrite eutectic salt system. By controlling the composition ratio of the nitrite system, nanomaterials can be synthesized from different metal salt precursors in one step at low temperature. This method offers advantages such as rapid and simultaneous nucleation of different metal salt precursors, controllable target product size, and direct synthesis of easily oxidizable phases, which are of great significance for their potential applications in various fields.

[0006] The technical solution adopted in this invention is as follows: A method for constructing nanomaterials based on a multi-component nitrite eutectic salt system involves placing sodium nitrite and potassium nitrite in an air muffle furnace and preheating them into molten salt; dissolving at least one metal salt in a solvent to obtain a precursor solution, mixing it with the molten salt to react, and then, after heat preservation, cooling, and washing, obtaining nanomaterials corresponding to the metal salt. The nanomaterial is a nanomaterial host, or a material in which at least one rare earth element is loaded in the bulk phase of the nanomaterial host in the form of a single atom; wherein, the nanomaterial host is a nano-metal or oxide nanomaterial. Different nanomaterials can be synthesized by controlling the mixing ratio of sodium nitrite and potassium nitrite and adjusting the holding temperature of different metal salts.

[0007] Furthermore, the rare earth element has a mass percentage of 0.5% to 2.5% in the nanomaterial.

[0008] Furthermore, the nano-metal is platinum, rhodium, iridium, or palladium, and the corresponding metal salt is platinum acetylacetonate, rhodium acetylacetonate, iridium acetylacetonate, or palladium nitrate. The oxide nanomaterials are copper oxide, cuprous oxide, aluminum oxide, iron oxide, manganese tetroxide, ruthenium oxide, cobalt tetroxide, nickel oxide, zinc oxide, indium oxide, tin oxide, cerium oxide, or yttrium oxide, and the corresponding metal salts are copper nitrate, cerium nitrate, iron nitrate, manganese nitrate, aluminum nitrate, cobalt nitrate, nickel nitrate, ruthenium chloride, zinc nitrate, indium nitrate, tin chloride, or yttrium nitrate. The rare earth element is lanthanum, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, or lutetium. When the nanomaterial is platinum, rhodium, or iridium, the metal salt corresponding to the rare earth element is acetylacetone. When the nanomaterial is palladium or an oxide nanomaterial, the metal salt corresponding to the rare earth element is a nitrate or a chloride.

[0009] Furthermore, when the nanomaterial is platinum, the potassium nitrite content in the molten salt is 0, that is, only sodium nitrite is used, and the holding temperature is 270 degrees Celsius.

[0010] Furthermore, when the nanomaterial is palladium, cuprous oxide, aluminum oxide, iron oxide, manganese tetroxide, ruthenium oxide, cobalt tetroxide, nickel oxide, copper oxide, zinc oxide, indium oxide, tin oxide, cerium oxide, or yttrium oxide, the molar ratio of sodium nitrite to potassium nitrite is 1:0.33~3, and the holding temperature is 350~450 degrees Celsius.

[0011] Furthermore, when the nanomaterial is rhodium or iridium, the molar ratio of sodium nitrite to potassium nitrite is 1:5~8, and the heat preservation temperature should be within 10 degrees Celsius higher than the melting point of the molten salt, specifically 350~400 degrees Celsius.

[0012] Furthermore, the solvent should fully dissolve the metal salt, and its solubility should be as high as possible.

[0013] Furthermore, when the nanomaterial is palladium, aluminum oxide, iron oxide, manganese tetroxide, ruthenium oxide, cobalt tetroxide, nickel oxide, copper oxide, zinc oxide, indium oxide, tin oxide, cerium oxide, or yttrium oxide, the solvent is deionized water with a concentration of 0.3~2 g / mL.

[0014] Furthermore, when the nanomaterial is cuprous oxide, the solvent is a saturated aqueous solution of disodium citrate, a saturated aqueous solution of disodium ethylenediaminetetraacetate, or a saturated aqueous solution of disodium tartrate.

[0015] Furthermore, when the nanomaterial is cuprous oxide, the concentration of copper nitrate in the resulting precursor solution is 0.3~0.6 g / mL.

[0016] Furthermore, when the nanomaterial is platinum, rhodium, or iridium, the solvent is acetone.

[0017] Furthermore, when the nanomaterial is palladium, cuprous oxide, aluminum oxide, iron oxide, manganese tetroxide, ruthenium oxide, cobalt tetroxide, nickel oxide, copper oxide, zinc oxide, indium oxide, tin oxide, cerium oxide, or yttrium oxide, the heat treatment time is 5 to 120 minutes.

[0018] Furthermore, the mass ratio of the metal salt to the molten salt is 1~8:100.

[0019] Furthermore, when the nanomaterial is platinum, rhodium, or iridium, the heat preservation time is 90-180 minutes.

[0020] Furthermore, the preheating time is 30 to 90 minutes.

[0021] Furthermore, the cooling process is carried out in room temperature air.

[0022] Furthermore, the specific cleaning process is as follows: first ultrasonic dispersion, then centrifugation, repeated 3 to 7 times; wherein, the ultrasonically dispersed washing solution is a mixed solution of isopropanol and deionized water with a volume ratio of 1:3 to 10; the ultrasonic dispersion time is 5 to 20 minutes; the centrifugation speed is 11,000 to 13,000 rpm, and the time is 3 to 8 minutes.

[0023] A method for constructing nanomaterials based on a multi-component nitrite eutectic salt system involves mixing sodium nitrite and potassium nitrite to form a nitrite; dissolving at least one metal salt in acetone to obtain a precursor solution, and then evaporating the acetone to obtain a precursor powder; preheating an air muffle furnace, mixing the precursor powder with the nitrite and grinding them evenly, then placing the mixture in the air muffle furnace for heat preservation, and finally cooling and cleaning to obtain nanomaterials corresponding to the metal salt. The nanomaterial is a nano-host material, or a material in which at least one rare earth element is loaded in the bulk phase of the nano-host material in the form of a single atom; wherein, the nano-host material is platinum, rhodium, or iridium, and the corresponding metal salt is platinum acetylacetonate, rhodium acetylacetonate, or iridium acetylacetonate; the rare earth element is lanthanum, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, or lutetium, and the corresponding metal salt is acetylacetonate; Different nanomaterials can be synthesized by controlling the mixing ratio of sodium nitrite and potassium nitrite and adjusting the holding temperature of different metal salts.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention proposes a method for constructing nanomaterials based on a multi-component nitrite eutectic salt system. By controlling the composition ratio of the nitrite system (sodium nitrite and potassium nitrite), nanomaterials are synthesized from different metal precursors in one step at low temperature. This includes the synthesis of the main nanomaterial and the construction of fine nanostructures supported by rare earth single atoms. The method has strong universality, and the synthesis process is simple and the post-reaction processing is convenient. Compared with other aqueous / oil phase nanomaterial synthesis methods, this invention can greatly avoid the contamination of the nanocrystal surface by organic additives. 2. This invention utilizes a nitrite-based molten salt system, with a melting temperature of 400 degrees Celsius and below, significantly lower than the 800 degrees Celsius of the traditional sodium chloride-potassium chloride molten salt system, making the operation process easier to implement. More importantly, compared to the traditional sodium chloride-potassium chloride molten salt system and nitrate molten salt system, it features flexible adjustment of various operating parameters, specifically including: 1) utilizing the high Lux-Flood alkalinity of nitrite to accelerate the nucleation rate of the target product, thereby synthesizing smaller nanomaterials; 2) controlling the melting point of the molten salt by changing the composition ratio of the nitrite system, thereby adjusting the viscosity of the molten salt and influencing the sintering behavior of nanocrystals during the molten nitrite process, avoiding agglomeration and achieving size control of nanomaterials; 3) utilizing the airtight salt-sealing effect of nitrite, easily oxidizable phases (such as cuprous oxide, metallic nanocrystals, etc.) can be directly synthesized in heated air. 3. This invention can construct fine nanostructures supported by rare earth single atoms, and has better compatibility with reactants that are incompatible with aqueous systems (such as platinum acetylacetonate, which has extremely poor water solubility). 4. The synthesis method provided by this invention has the characteristics of broad reactant compatibility, product diversity and controllable reaction environment, and can achieve selective preparation of nanomaterials with multiple components and complex structures. This will provide a brand-new preparation platform for the wide application of nanomaterials in a variety of fields. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 The elemental distribution results of different nanomaterials loaded with dysprosium single atoms obtained in Example 1 of the present invention under scanning transmission electron microscopy include: (A) nano-alumina loaded with dysprosium single atoms, (B) nano-iron oxide loaded with dysprosium single atoms, (C) nano-manganese tetroxide loaded with dysprosium single atoms, and (D) nano-ruthenium oxide loaded with dysprosium single atoms. Figure 2 The elemental distribution results of different nanomaterials loaded with dysprosium single atoms obtained in Example 1 of this invention under scanning transmission electron microscopy include: (A) nano-cobalt tetroxide loaded with dysprosium single atoms, (B) nano-nickel oxide loaded with dysprosium single atoms, (C) nano-copper oxide loaded with dysprosium single atoms, and (D) nano-zinc oxide loaded with dysprosium single atoms. Figure 3The elemental distribution results of different nanomaterials loaded with dysprosium single atoms obtained in Example 1 of the present invention under scanning transmission electron microscopy include: (A) palladium nanoparticles loaded with dysprosium single atoms, (B) indium nanoparticles loaded with dysprosium single atoms, (C) tin nanoparticles loaded with dysprosium single atoms, (D) yttrium nanoparticles loaded with dysprosium single atoms, and (E) cerium nanoparticles loaded with dysprosium single atoms. Figure 4 The image shown is a high-angle annular dark-field image obtained by scanning transmission electron microscopy with spherical aberration correction for copper oxide nanomaterials loaded with different rare earth single atoms obtained in Example 2 of this invention. The types of single atoms include: (A) lanthanum, (B) praseodymium, (C) neodymium, (D) samarium, (E) europium, (F) gadolinium, (G) terbium, (H) holmium, (I) erbium, (J) thulium, (K) ytterbium, and (L) lutetium. Figure 5 The characterization results of the platinum / rhodium / iridium nanomaterials loaded with dysprosium single atoms obtained in Example 3 of the present invention include: (A) elemental distribution results of the platinum nanomaterials loaded with dysprosium single atoms under scanning transmission electron microscopy, (B) X-ray diffraction pattern of the platinum nanomaterials loaded with dysprosium single atoms, (C) elemental distribution results of the rhodium nanomaterials loaded with dysprosium single atoms under scanning transmission electron microscopy, (D) X-ray diffraction pattern of the rhodium nanomaterials loaded with dysprosium single atoms, (E) elemental distribution results of the iridium nanomaterials loaded with dysprosium single atoms, and (F) X-ray diffraction pattern of the iridium nanomaterials loaded with dysprosium single atoms. Figure 6 The characterization results of the cuprous oxide nanomaterial loaded with dysprosium single atoms obtained in Example 4 of the present invention include: (A) a high-angle annular dark field image corrected by scanning transmission electron microscopy, and (B) elemental distribution results obtained by scanning transmission electron microscopy. Figure 7 The characterization results of the copper oxide nanomaterial simultaneously loaded with multiple rare earth single atoms obtained in Example 5 of the present invention include: (A) a high-angle annular dark field image corrected by scanning transmission electron microscopy, (B) the selected region of energy scattering X-ray spectroscopy, (C) a schematic diagram of the superimposed elemental distribution results, and (D) the distribution results of each rare earth element and copper element. Figure 8 The characterization results of the copper oxide nanomaterial obtained in Example 6 of the present invention include: (A) X-ray diffraction pattern, (B) transmission electron microscopy imaging results; Figure 9 The transmission electron microscopy characterization results of different groups of copper oxide nanomaterials loaded with lanthanum single atoms obtained in Comparative Example 1 are included: (A) Group 1, (B) Group 2, (C) Group 3, and (D) Group 4. Figure 10 The full width at half maximum (FWHM) of the main X-ray diffraction peak of copper oxide in different groups of copper oxide nanomaterials loaded with lanthanum single atoms obtained in Comparative Example 1 is shown in the figure. Figure 11 The transmission electron microscopy characterization results of the two groups of platinum nanomaterials loaded with dysprosium single atoms obtained in Comparative Example 2 are as follows: (A) Group 2, (B) Group 1; Figure 12 The image shows a comparison of the full width at half maximum (FWHM) of the main X-ray diffraction peak of platinum in the two sets of platinum nanomaterials loaded with dysprosium single atoms obtained in Comparative Example 2. Figure 13 The photograph of the inside of the crucible in Comparative Example 3 includes: (A) Step 1, (B) Step 3, (C) Step 4, (D) Step 5; Figure 14 The X-ray diffraction patterns of different groups of cuprous oxide nanomaterials loaded with dysprosium single atoms are shown in Comparative Example 3. Detailed Implementation

[0027] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims.

[0028] There are no particular restrictions on the source of any raw materials used in this invention; they can be purchased from the market or prepared using conventional methods known to those skilled in the art.

[0029] The purity of all raw materials used in this invention is not particularly limited, but analytical grade or the purity requirements conventional in the field of atomic layer deposition are preferred.

[0030] All raw materials and processes of this invention are designated by or abbreviated as conventional designations or abbreviations in the field. Each designation or abbreviation is clearly defined in its relevant application area. Those skilled in the art can purchase them from commercially available sources or prepare them by conventional methods, or implement them using appropriate equipment, based on the designation, abbreviation, and corresponding application.

[0031] To further illustrate the present invention, the following describes in detail the method for constructing nanomaterials based on a multi-component nitrite eutectic salt system provided by the present invention with reference to embodiments. However, it should be understood that these embodiments are implemented under the premise of the technical solution of the present invention, and detailed implementation methods and specific operation processes are given only to further illustrate the features and advantages of the present invention, and are not intended to limit the scope of the claims of the present invention. The scope of protection of the present invention is not limited to the following embodiments.

[0032] Example 1

[0033] This embodiment prepared a series of different nanomaterials loaded with dysprosium single atoms, specifically including the following steps: Step 1: Weigh 2.24 g of sodium nitrite and 2.76 g of potassium nitrite into a 50 ml corundum crucible, mix them simply, and then preheat them in a muffle furnace at 400 degrees Celsius for 60 minutes to obtain molten salt; Step 2: Weigh 0.2 g of the metal salt corresponding to different nanomaterials (specifically copper nitrate, cerium nitrate, iron nitrate, manganese nitrate, aluminum nitrate, cobalt nitrate, nickel nitrate, ruthenium chloride, zinc nitrate, palladium nitrate, indium nitrate, tin chloride, or yttrium nitrate), and a certain mass of dysprosium nitrate (keeping the molar ratio of dysprosium nitrate to the metal ions of the metal salt at 1:100), and dissolve both together in 150 μL of deionized water (ruthenium chloride requires 350 μL of deionized water due to its solubility) to obtain the precursor solution; Step 3: Add the precursor solution to the preheated molten salt, and continue to keep it warm for 30 minutes after no obvious reaction occurs; Step 4: After the heat preservation is completed, remove the crucible from the furnace and allow it to cool naturally to room temperature; wash with a mixed solvent of 30 mL deionized water and 5 mL isopropanol to remove nitrite, and centrifuge at 12000 rpm for 5 minutes to collect the product; add 30 mL deionized water and 5 mL isopropanol back to the collected product, sonicate for 10 minutes, and continue to centrifuge at 12000 rpm for 5 minutes to collect the product; repeat this operation 4 times, and dry the obtained sample under vacuum to obtain different nanomaterials loaded with dysprosium single atoms.

[0034] Inductively coupled plasma atomic emission spectrometry (ICP-AES) analysis revealed that the mass fraction of dysprosium in the different nanomaterials loaded with dysprosium single atoms was between 1% and 2%, and the materials exhibited uniform morphology and were nanoscale in size.

[0035] Scanning transmission electron microscopy was used to test the different nanomaterials loaded with dysprosium single atoms obtained in this embodiment. Figure 1 , Figure 2 and Figure 3 This is a schematic diagram of the elemental distribution of each product at the nanoscale, where... Figure 1 (A) Nano-alumina loaded with dysprosium single atoms, Figure 1 (B) Nano-iron oxide loaded with dysprosium single atoms, Figure 1 (C) Manganese tetroxide nanoparticles supported on dysprosium single atoms, Figure 1 (D) ruthenium oxide nanoparticles supported on dysprosium single atoms, Figure 2 (A) Cobalt tetroxide nanoparticles loaded with dysprosium single atoms, Figure 2 (B) Nanoscale nickel oxide supported on dysprosium single atoms, Figure 2 (C)-loaded dysprosium single-atom copper oxide nanoparticles, Figure 2 (D) zinc oxide nanoparticles supported on dysprosium single atoms, Figure 3 (A) Palladium nanoparticles supported on dysprosium single atoms, Figure 3 (B) Nanoscale indium oxide supported on dysprosium single atoms, Figure 3 (C)-loaded dysprosium single-atom nano-tin oxide, Figure 3 (D) Yttrium oxide nanoparticles supported on dysprosium single atoms, Figure 3 The (E) loaded dysprosium single-atom nano-cerium oxides all indicate that the incorporated rare earth elements are uniformly dispersed on the nano-host material, realizing the construction of fine nanostructures loaded with rare earth single atoms.

[0036] Example 2

[0037] This embodiment prepared a series of copper oxide nanomaterials loaded with different rare earth single atoms, specifically including the following steps: Step 1: Weigh 2.24 g of sodium nitrite and 2.76 g of potassium nitrite into a 50 ml corundum crucible, mix them simply, and then preheat them in a muffle furnace at 400 degrees Celsius for 60 minutes to obtain molten salt; Step 2: Weigh 0.2 g of copper nitrate and 8.3 μmol of different rare earth nitrates (specifically lanthanum nitrate, praseodymium nitrate, neodymium nitrate, samarium nitrate, europium nitrate, gadolinium nitrate, terbium nitrate, holmium nitrate, erbium nitrate, thulium nitrate, ytterbium nitrate, or lutetium nitrate), and dissolve both in 150 μL of deionized water to obtain the precursor solution; Step 3: Add the precursor solution to the preheated molten salt, and continue to keep it warm for 30 minutes after no obvious reaction occurs; Step 4: After the heat preservation is completed, remove the crucible from the furnace and allow it to cool naturally to room temperature; wash with a mixed solvent of 30 ml deionized water and 5 ml isopropanol to remove nitrite, and centrifuge at 12000 rpm for 5 minutes to collect the product; add 30 ml deionized water and 5 ml isopropanol back to the collected product, sonicate for 10 minutes, and continue to centrifuge at 12000 rpm for 5 minutes to collect the product; repeat this operation 4 times, and dry the obtained sample under vacuum to obtain copper oxide nanomaterials loaded with different rare earth single atoms.

[0038] Inductively coupled plasma atomic emission spectrometry (ICP-AES) analysis revealed that the mass fraction of rare earth elements in the copper oxide nanomaterials loaded with different rare earth single atoms was between 1% and 2%, and the materials exhibited uniform morphology and were nanoscale in size.

[0039] The copper oxide nanomaterials loaded with different rare earth single atoms obtained in this embodiment were tested by scanning transmission electron microscopy. Figure 4 These are high-angle annular dark-field images of the single-atom structures of each product, corrected for spherical aberration using scanning transmission electron microscopy. Figure 4 (A) Lanthanum, Figure 4 (B) Praseodymium, Figure 4 (C)neodymium, Figure 4 (D) samarium, Figure 4 (E) europium, Figure 4 (F)gadolinium, Figure 4 (G) terbium, Figure 4 (H) holmium, Figure 4 (I) Erbium, Figure 4 (J) thulium, Figure 4 (K) Ytterbium, Figure 4 The presence of (L) lutetium indicates that all the rare earth single atoms incorporated are uniformly and independently dispersed on the copper oxide nanomaterial.

[0040] Example 3

[0041] This embodiment prepares a platinum / rhodium / iridium nanomaterial host material loaded with dysprosium single atoms, specifically including the following steps: Step 1: Dissolve 47 mg of dysprosium acetylacetonate in 20 mL of acetone to obtain a dysprosium solution; Step 2: For platinum nanomaterials loaded with dysprosium single atoms, mix 1 mL of dysprosium solution with 10 mL of acetone and 100 mg of platinum acetylacetonate; for rhodium nanomaterials loaded with dysprosium single atoms, mix 0.98 mL of dysprosium solution with 20 mL of acetone and 100 mg of rhodium acetylacetonate; for iridium nanomaterials loaded with dysprosium single atoms, mix 0.8 mL of dysprosium solution with 10 mL of acetone and 100 mg of iridium acetylacetonate; finally, the corresponding transparent and homogeneous precursor solutions are obtained. Step 3: Evaporate and dry the precursor solution obtained in Step 2 in an 80°C water bath to obtain a uniform yellow powder; Step 4: For platinum nanomaterials loaded with dysprosium single atoms, grind and mix the resulting yellow powder with 5 grams of sodium nitrite and place it in a muffle furnace at 270 degrees Celsius for 90 minutes; for rhodium / iridium nanomaterials loaded with dysprosium single atoms, first melt 9.25 grams of potassium nitrite and 1.5 grams of sodium nitrite at 400 degrees Celsius, then grind and mix the resulting yellow powder with 4 grams of potassium bromide to obtain a salt powder with a higher density, and then mix the pre-melted nitrite eutectic salt with the obtained salt powder and place it in a muffle furnace at 350 degrees Celsius for 90 minutes. Step 5: After the heat preservation is completed, remove the crucible from the furnace and allow it to cool naturally to room temperature; wash with a mixed solvent of 30 mL deionized water and 5 mL isopropanol to remove nitrite, and centrifuge at 12000 rpm for 5 minutes to collect the product; add 30 mL deionized water and 5 mL isopropanol back to the collected product, sonicate for 10 minutes, and continue to centrifuge at 12000 rpm for 5 minutes to collect the product; repeat this operation 4 times, and dry the obtained sample under vacuum to obtain the platinum / rhodium / iridium nanomaterial host material loaded with dysprosium single atoms.

[0042] Inductively coupled plasma atomic emission spectrometry (ICP-AES) analysis revealed that the mass fraction of rare earth elements in the obtained platinum / rhodium / iridium nanomaterials loaded with dysprosium single atoms was between 1% and 2%, and the materials exhibited uniform morphology and were nanoscale in size.

[0043] The platinum / rhodium / iridium nanomaterials loaded with dysprosium single atoms obtained in this embodiment were subjected to scanning transmission electron microscopy and X-ray diffraction spectroscopy tests. Figure 5 The test results include... Figure 5 (A) Scanning transmission electron microscopy elemental distribution of platinum nanomaterials loaded with dysprosium single atoms. Figure 5 (B) X-ray diffraction pattern of platinum nanomaterials loaded with dysprosium single atoms. Figure 5 (C) Scanning transmission electron microscopy elemental distribution of rhodium nanomaterials loaded with dysprosium single atoms. Figure 5 X-ray diffraction pattern of (D) rhodium nanomaterials loaded with dysprosium single atoms. Figure 5 (E) Scanning transmission electron microscopy elemental distribution results of iridium nanomaterials loaded with dysprosium single atoms. Figure 5 The X-ray diffraction spectra of the (F) iridium nanomaterials loaded with dysprosium single atoms all indicate that the incorporated rare earth elements are uniformly dispersed on the nanomaterials and no impurity phases are generated.

[0044] Example 4

[0045] This embodiment prepares a cuprous oxide nanomaterial loaded with dysprosium single atoms, specifically including the following steps: Step 1: Weigh 2.24 g of sodium nitrite and 2.76 g of potassium nitrite into a 50 ml corundum crucible, mix them simply, and then preheat them in a muffle furnace at 400 degrees Celsius for 60 minutes to obtain molten salt; Step 2: Weigh 0.2 g of copper nitrate and 8.3 μmol of dysprosium nitrate, and dissolve them together in 350 μL of saturated disodium citrate solution to obtain the precursor solution; Step 3: Add the precursor solution to the preheated molten salt, and continue to keep it warm for 30 minutes after no obvious reaction occurs; Step 4: After the heat preservation is completed, remove the crucible from the furnace and allow it to cool naturally to room temperature; wash with a mixed solvent of 30 mL deionized water and 5 mL isopropanol to remove nitrite, and centrifuge at 12000 rpm for 5 minutes to collect the product; add 30 mL deionized water and 5 mL isopropanol back to the collected product, sonicate for 10 minutes, and continue to centrifuge at 12000 rpm for 5 minutes to collect the product; repeat this operation 4 times, and dry the obtained sample under vacuum to obtain cuprous oxide nanomaterials loaded with dysprosium single atoms.

[0046] Inductively coupled plasma atomic emission spectrometry (ICP-AES) analysis revealed that the mass fraction of dysprosium in the obtained cuprous oxide nanomaterial loaded with dysprosium single atoms was between 1% and 2%, and the material exhibited uniform morphology and nanoscale size.

[0047] The cuprous oxide nanomaterials loaded with dysprosium single atoms obtained in this embodiment were tested by scanning transmission electron microscopy. Figure 6 To characterize the results, where Figure 6 (A) Scanning transmission electron microscopy image with spherical aberration correction at high angles and annular dark field. Figure 6 The elemental distribution results of (B) scanning transmission electron microscopy show that dysprosium single atoms are uniformly and independently distributed and loaded on the surface of cuprous oxide nanomaterial.

[0048] Example 5

[0049] This embodiment prepares a copper oxide nanomaterial simultaneously loaded with multiple rare earth single atoms, specifically including the following steps: Step 1: Weigh 2.24 g of sodium nitrite and 2.76 g of potassium nitrite into a 50 ml corundum crucible, mix them simply, and then preheat them in a muffle furnace at 400 degrees Celsius for 60 minutes to obtain molten salt; Step 2: Weigh 0.2 g of copper nitrate, 2.1 μmol of lanthanum nitrate, 2.1 μmol of samarium nitrate, 2.1 μmol of dysprosium nitrate and 2.1 μmol of lutetium nitrate, and dissolve all raw materials together in 150 μL of deionized water to obtain the precursor solution; Step 3: Add the precursor solution to the preheated molten salt, and continue to keep it warm for 30 minutes after no obvious reaction occurs; Step 4: After the heat preservation is completed, remove the crucible from the furnace and allow it to cool naturally to room temperature; wash with a mixed solvent of 30 ml deionized water and 5 ml isopropanol to remove nitrite, and centrifuge at 12000 rpm for 5 minutes to collect the product; add 30 ml deionized water and 5 ml isopropanol back to the collected product, sonicate for 10 minutes, and continue to centrifuge at 12000 rpm for 5 minutes to collect the product; repeat this operation 4 times, and dry the obtained sample under vacuum to obtain copper oxide nanomaterials simultaneously loaded with multiple rare earth single atoms.

[0050] According to inductively coupled plasma atomic emission spectrometry, the mass fraction of rare earth elements in the copper oxide nanomaterial simultaneously loaded with multiple rare earth single atoms is between 1% and 2%, and the material has a uniform morphology and a size in the nanometer range.

[0051] The copper oxide nanomaterials simultaneously loaded with multiple rare earth single atoms obtained in this embodiment were subjected to scanning transmission electron microscopy tests. Figure 7 To characterize the results, where Figure 7(A) Scanning transmission electron microscopy image with spherical aberration correction at high angles and annular dark field. Figure 7 (B) Selected region of energy-scattered X-ray spectrum Figure 7 A schematic diagram of the overlay of the distribution results of element (C). Figure 7 The distribution results of rare earth elements and copper in (D) show that lanthanum, samarium, dysprosium and lutetium rare earth single atoms are uniformly and independently dispersed and loaded on the surface of copper oxide nanomaterial.

[0052] Example 6

[0053] This embodiment prepares a pure copper oxide phase nanomaterial, specifically including the following steps: Step 1: Weigh 2.24 g of sodium nitrite and 2.76 g of potassium nitrite into a 50 ml corundum crucible, mix them simply, and then preheat them in a muffle furnace at 400 degrees Celsius for 60 minutes to obtain molten salt; Step 2: Weigh 0.2 g of copper nitrate trihydrate and dissolve it in 150 μL of deionized water to obtain the precursor solution; Step 3: Add the precursor solution to the preheated molten salt, and continue to keep it warm for 30 minutes after no obvious reaction occurs; Step 4: After the heat preservation is completed, remove the crucible from the furnace and allow it to cool naturally to room temperature; wash with a mixed solvent of 30 ml deionized water and 5 ml isopropanol to remove nitrite, and centrifuge at 12000 rpm for 5 minutes to collect the product; add 30 ml deionized water and 5 ml isopropanol back to the collected product, sonicate for 10 minutes, and continue to centrifuge at 12000 rpm for 5 minutes to collect the product; repeat this operation 4 times, and dry the obtained sample under vacuum to obtain the copper oxide nanomaterial.

[0054] The copper oxide nanomaterial obtained in this embodiment was subjected to X-ray diffraction and transmission electron microscopy tests, wherein... Figure 8 X-ray diffraction pattern of (A) copper oxide nanoparticles, Figure 8 Transmission electron microscopy imaging results of (B) copper oxide nanoparticles all indicate that spherical copper oxide nanoparticles with a size of less than 30 nanometers, a pure phase, and a uniform morphology were synthesized.

[0055] Comparative Example 1 This comparative study investigated in detail the effect of Lux-Flood basicity of nitrite eutectic salts on the nucleation results of nanocrystals. Compared with traditional nitrate eutectic salts, nitrite eutectic salts exhibit stronger Lux-Flood basicity, which can induce rapid nucleation of metal ions, thereby obtaining smaller nanoparticles. Simultaneously, sufficient Lux-Flood basicity can promote uniform nucleation of multiple components.

[0056] This comparative example includes four sets of parallel experiments, specifically following these steps: Step 1: Prepare four different sets of molten salts and preheat them. Group 1: Weigh 2.28 g of sodium nitrate and 2.72 g of potassium nitrate into a 50 ml corundum crucible, mix them simply, and then preheat them in a muffle furnace at 400 degrees Celsius for 60 minutes to obtain molten salt; Group 2: Weigh 2.28 g of sodium nitrate, 2.72 g of potassium nitrate and 0.02 g of sodium nitrite into a 50 ml corundum crucible, mix them simply and then preheat them in a muffle furnace at 400 degrees Celsius for 60 minutes to obtain molten salt; Group 3: Weigh 2.28 g of sodium nitrate, 2.72 g of potassium nitrate and 0.05 g of sodium nitrite into a 50 ml corundum crucible, mix them simply and then preheat them in a muffle furnace at 400 degrees Celsius for 60 minutes to obtain molten salt; Group 4: Weigh 2.24 g of sodium nitrite and 2.78 g of potassium nitrite into a 50 ml corundum crucible, mix them simply, and then preheat them in a muffle furnace at 400 degrees Celsius for 60 minutes to obtain molten salt; Step 2: Weigh 0.2 g of copper nitrate and 8.3 μmol of lanthanum nitrate, and dissolve them together in 150 μL of deionized water to obtain the precursor solution; Step 3: Add the precursor solution to each group of preheated molten salts, and continue to keep warm for 30 minutes after no obvious reaction occurs; Step 4: After the heat preservation is completed, remove each group of crucibles from the furnace and allow them to cool naturally to room temperature; wash each crucible with a mixed solvent of 30 ml deionized water and 5 ml isopropanol to remove molten salt, and centrifuge at 12000 rpm for 5 minutes to collect the product; add 30 ml deionized water and 5 ml isopropanol to the collected product and sonicate for 10 minutes, then centrifuge at 12000 rpm for 5 minutes to collect the product; repeat this operation 4 times, and dry the obtained samples under vacuum to obtain different groups of copper oxide nanomaterials loaded with lanthanum single atoms.

[0057] The copper oxide nanomaterials loaded with lanthanum single atoms in different groups obtained in this comparative example were characterized by transmission electron microscopy and X-ray diffraction.

[0058] Figure 9 The results are from transmission electron microscopy characterization, among which Figure 9 (A) corresponds to group 1. Figure 9 (B) corresponds to group 2. Figure 9 (C) corresponds to group 3. Figure 9 (D) corresponds to group 4. The characterization results show that the size of the obtained copper oxide nanoparticles decreases sequentially from (A) to (D), indicating that nitrite can promote the formation of smaller and more uniform copper oxide particles.

[0059] Figure 10 The image shows a comparison of the full width at half maximum (FWHM) of the main peak of copper oxide in X-ray diffraction. It can be seen that the main peak width of each group of samples increases sequentially from group 1 to group 4. According to the Scherrer equation, the relationship between peak width and grain size indicates that nitrite can promote the formation of smaller and more uniform copper oxide particles.

[0060] The residual metal ion concentrations of the molten salts used in Groups 1 and 4 of this comparative example were quantified by inductively coupled atomic emission spectrometry. Table 1 shows the copper and dysprosium ion concentrations in the supernatant of the molten salts used in Groups 1 and 4 after washing away the generated oxide particles following the addition of the precursor and heat preservation. It can be seen that a small amount of copper ions and a large amount of dysprosium ions were unreacted in the nitrate system molten salt, while all metal ions were completely reacted in the nitrite system molten salt. This indicates that compared with the nitrate system molten salt, the nitrite system molten salt can promote the rapid and simultaneous nucleation of different metal precursors.

[0061] Table 1 Types of molten salt Copper ion concentration dysprosium ion concentration Group 4 <0.1 micrograms per milliliter <0.1 micrograms per milliliter Group 1 0.14 micrograms per milliliter 21.02 micrograms per milliliter Comparative Example 2 This comparative study investigated the viscosity properties of nitrite eutectic salts near their melting points in detail. The overall viscosity of the molten salt was adjusted by changing the proportions of various nitrates in the nitrite system. Introducing a high-viscosity molten salt suppressed the sintering and overgrowth of the formed nanocrystals in the high-temperature molten salt.

[0062] This comparative example includes two sets of parallel experiments, and the specific procedures are as follows: Step 1: Dissolve 47 mg of dysprosium acetylacetonate in 20 mL of acetone to obtain a dysprosium solution; Step 2: For the platinum nanomaterials loaded with dysprosium single atoms, mix 1 mL of dysprosium solution with 10 mL of acetone and 100 mg of platinum acetylacetonate to obtain a transparent and homogeneous precursor solution. In this step, prepare two identical sets of precursor solutions for subsequent comparative experiments. Step 3: The precursor solution obtained in Step 2 was evaporated and dried in an 80°C water bath to obtain two sets of identical yellow precursor powders; Step 4: Mix the two groups of precursor powders with nitrite, wherein: Group 1: The obtained precursor powder was ground and mixed with 5 grams of sodium nitrite, and then placed in a muffle furnace at 270 degrees Celsius for 90 minutes. Group 2: The obtained precursor powder was mixed with 5 grams of sodium nitrite-potassium nitrite mixed molten salt and then placed in a muffle furnace at 270 degrees Celsius and kept warm for 90 minutes; wherein, the formula of 5 grams of sodium nitrite-potassium nitrite mixed molten salt is to obtain a uniform mixed molten salt by mixing 2.24 grams of sodium nitrite and 2.76 grams of potassium nitrite and preheating it in a muffle furnace at 270 degrees Celsius for 60 minutes. Step 5: After the heat preservation is completed, remove the crucible from the furnace and allow it to cool naturally to room temperature; wash with a mixed solvent of 30 ml deionized water and 5 ml isopropanol to remove nitrite, and centrifuge at 12000 rpm for 5 minutes to collect the product; add 30 ml deionized water and 5 ml isopropanol back to the collected product and sonicate for 10 minutes, then centrifuge at 12000 rpm for 5 minutes to collect the product; repeat this operation 4 times, and dry the obtained samples under vacuum to obtain two groups of platinum nanomaterials loaded with dysprosium single atoms, namely Group 1 and Group 2.

[0063] The two sets of platinum nanomaterials loaded with dysprosium single atoms obtained in this comparative example were characterized by transmission electron microscopy. Figure 11 The results are from transmission electron microscopy characterization, among which Figure 11 (A) corresponds to group 2. Figure 11 (B) corresponds to group 1. It can be seen that the size of platinum nanoparticles formed in pure sodium nitrite with a melting point close to 270 degrees Celsius is significantly smaller than that formed in a sodium nitrite-potassium nitrite mixed molten salt with a melting point of approximately 230 degrees Celsius. This conclusion can also be drawn from… Figure 12 The comparison of the full width at half maximum (FWHM) of the main X-ray diffraction peak of platinum in the two sets of platinum nanomaterials loaded with dysprosium single atoms demonstrates this. Since the viscosity of molten salt increases significantly near its melting point, the viscosity of nitrite can be adjusted by changing the component ratio, thereby controlling the size of the formed nanocrystals.

[0064] Comparative Example 3 This comparative study details the airtight salt-sealing properties of nitrite-based eutectic salts. The main characteristic is that the nanoparticles formed in the nitrite-based eutectic salt are prevented from contacting air by being immersed in the molten salt. Therefore, phases that are easily oxidized in air can be successfully formed in nitrite-based eutectic salts.

[0065] The specific steps for this comparison are as follows: Step 1: Weigh 2.24 g of sodium nitrite and 2.76 g of potassium nitrite into a 50 ml corundum crucible, mix them simply, and then preheat them in a muffle furnace at 400 degrees Celsius for 60 minutes to obtain molten salt. After that, take a picture of the inside of the crucible. Step 2: Weigh 0.2 g of copper nitrate and 8.3 μmol of dysprosium nitrate, and dissolve them together in 350 μL of saturated disodium citrate solution to obtain the precursor solution; Step 3: Add the precursor solution to the preheated molten salt and shake vigorously. Take a picture of the inside of the crucible. Step 4: After no obvious reaction occurs, continue to keep warm for 30 minutes, then take a picture of the inside of the crucible; Step 5: After the heat preservation is completed, remove the crucible from the furnace and allow it to cool naturally to room temperature. Take a picture of the inside of the crucible.

[0066] The four photos taken are as follows Figure 13 As shown, where Figure 13 (A) is step 1. Figure 13 (B) is step 3. Figure 13 (C) is step 4. Figure 13 (D) represents step 5. Before the precursor solution was added in step 1, the molten salt was light yellow. After adding the precursor solution and shaking vigorously in step 3, a large amount of characteristic orange-red cuprous oxide was found to have formed in the molten salt, and a large amount of orange-red cuprous oxide was also found on the crucible wall. After holding the temperature for a period of time in step 4, it was found that the cuprous oxide in the molten salt remained orange-red, while the cuprous oxide adhering to the crucible wall was oxidized into characteristic black copper oxide due to the lack of molten salt coverage. After cooling in step 5, it was found that the cuprous oxide was covered by white molten salt. These experimental results show that cuprous oxide, which is easily oxidized by air, can be successfully protected by molten nitrite, thus proving the airtight salt sealing effect of molten salt in the nitrite system.

[0067] Keeping all other steps the same, except for extending the holding time in step 4 to conduct multiple sets of experiments, specifically extending it to 30, 60, 120, 240, and 360 minutes respectively. After the holding time, each set of crucibles was removed from the furnace and allowed to cool naturally to room temperature; each crucible was washed with a mixed solvent of 30 mL deionized water and 5 mL isopropanol to remove molten salt, and then centrifuged at 12,000 rpm for 5 minutes to collect the product; the collected product was then re-added with 30 mL deionized water and 5 mL isopropanol and sonicated for 10 minutes, and then centrifuged again at 12,000 rpm for 5 minutes to collect the product; this operation was repeated 4 times, and the resulting samples were dried under vacuum to obtain different sets of cuprous oxide nanomaterials loaded with dysprosium single atoms.

[0068] X-ray diffraction characterization was performed on the cuprous oxide nanomaterials loaded with dysprosium single atoms obtained in this comparative example. The results are as follows: Figure 14 As shown, when the holding time was extended to 30, 60, 120, 240, and 360 minutes, the samples obtained in each group all maintained a pure cuprous oxide phase and were not oxidized to copper oxide. Therefore, the molten salt in the nitrite system can continuously protect the formed cuprous oxide from oxidation by air, thus fully demonstrating the airtight salt sealing effect of the molten salt in the nitrite system.

[0069] The foregoing has provided a detailed description of a general synthesis method for synthesizing various nanomaterials using a multi-component nitrite eutectic salt. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of these embodiments are merely illustrative of the method and its core ideas, including the best mode, and are intended to enable any person skilled in the art to practice this invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that those skilled in the art can make various improvements and modifications to this invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims. The scope of protection of this patent is defined by the claims and may include other embodiments conceived by those skilled in the art. If these other embodiments have structural elements that are not different from the wording of the claims, or if they include equivalent structural elements that are not substantially different from the wording of the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. A method for constructing nanomaterials based on a multi-component nitrite eutectic salt system, characterized in that, Sodium nitrite and potassium nitrite are preheated in an air muffle furnace to form molten salt; at least one metal salt is dissolved in a solvent to obtain a precursor solution, which is then mixed with the molten salt to react. After heat preservation, cooling and washing, nanomaterials corresponding to the metal salt are obtained. The nanomaterial is a nanomaterial host, or a material in which at least one rare earth element is loaded in the bulk phase of the nanomaterial host in the form of a single atom; wherein, the nanomaterial host is a nano-metal or oxide nanomaterial. Different nanomaterials can be synthesized by controlling the mixing ratio of sodium nitrite and potassium nitrite and adjusting the holding temperature of different metal salts.

2. The method for constructing nanomaterials based on a multi-component nitrite eutectic salt system according to claim 1, characterized in that, The rare earth elements in the nanomaterials account for 0.5% to 2.5% of the total mass.

3. The method for constructing nanomaterials based on a multi-component nitrite eutectic salt system according to claim 1, characterized in that, The nano-metal is platinum, rhodium, iridium or palladium, and the corresponding metal salt is platinum acetylacetonate, rhodium acetylacetonate, iridium acetylacetonate or palladium nitrate. The oxide nanomaterials are copper oxide, cuprous oxide, aluminum oxide, iron oxide, manganese tetroxide, ruthenium oxide, cobalt tetroxide, nickel oxide, zinc oxide, indium oxide, tin oxide, cerium oxide, or yttrium oxide, and the corresponding metal salts are copper nitrate, cerium nitrate, iron nitrate, manganese nitrate, aluminum nitrate, cobalt nitrate, nickel nitrate, ruthenium chloride, zinc nitrate, indium nitrate, tin chloride, or yttrium nitrate. The rare earth element is lanthanum, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, or lutetium. When the nanomaterial is platinum, rhodium, or iridium, the metal salt corresponding to the rare earth element is acetylacetone. When the nanomaterial is palladium or an oxide nanomaterial, the metal salt corresponding to the rare earth element is a nitrate or a chloride.

4. The method for constructing nanomaterials based on a multi-component nitrite eutectic salt system according to claim 3, characterized in that, When the main nanomaterial is platinum, the potassium nitrite content in the molten salt is 0, that is, only sodium nitrite is used, and the heat preservation temperature is 270 degrees Celsius.

5. The method for constructing nanomaterials based on a multi-component nitrite eutectic salt system according to claim 3, characterized in that, When the main nanomaterial is palladium, cuprous oxide, aluminum oxide, iron oxide, manganese tetroxide, ruthenium oxide, cobalt tetroxide, nickel oxide, copper oxide, zinc oxide, indium oxide, tin oxide, cerium oxide, or yttrium oxide, the molar ratio of sodium nitrite to potassium nitrite is 1:0.33~3, and the holding temperature is 350~450 degrees Celsius.

6. The method for constructing nanomaterials based on a multi-component nitrite eutectic salt system according to claim 3, characterized in that, When the nanomaterial is rhodium or iridium, the molar ratio of sodium nitrite to potassium nitrite is 1:5~8, and the heat preservation temperature is within 10 degrees Celsius higher than the melting point of the molten salt.

7. The method for constructing nanomaterials based on a multi-component nitrite eutectic salt system according to claim 3, characterized in that, When the nanomaterial is palladium, aluminum oxide, iron oxide, manganese tetroxide, ruthenium oxide, cobalt tetroxide, nickel oxide, copper oxide, zinc oxide, indium oxide, tin oxide, cerium oxide, or yttrium oxide, the solvent is deionized water; when the nanomaterial is platinum, rhodium, or iridium, the solvent is acetone; when the nanomaterial is cuprous oxide, the solvent is a saturated aqueous solution of disodium citrate, a saturated aqueous solution of disodium ethylenediaminetetraacetate, or a saturated aqueous solution of disodium tartrate.

8. The method for constructing nanomaterials based on a multi-component nitrite eutectic salt system according to claim 3, characterized in that, When the main nanomaterial is palladium, cuprous oxide, aluminum oxide, iron oxide, manganese tetroxide, ruthenium oxide, cobalt tetroxide, nickel oxide, copper oxide, zinc oxide, indium oxide, tin oxide, cerium oxide, or yttrium oxide, the holding time is 5 to 120 minutes; when the main nanomaterial is platinum, rhodium, or iridium, the holding time is 90 to 180 minutes.

9. The method for constructing nanomaterials based on a multi-component nitrite eutectic salt system according to claim 3, characterized in that, The mass ratio of the metal salt to the molten salt is 1~8:

100.

10. A method for constructing nanomaterials based on a multi-component nitrite eutectic salt system, characterized in that, Sodium nitrite and potassium nitrite are mixed to form nitrite; at least one metal salt is dissolved in acetone to obtain a precursor solution, and the precursor powder is obtained after evaporating the acetone; an air muffle furnace is preheated, the precursor powder is mixed with nitrite and ground evenly, and then placed in the air muffle furnace for heat preservation. After cooling and cleaning, nanomaterials corresponding to the metal salt are obtained. The nanomaterial is a nano-host material, or a material in which at least one rare earth element is loaded in the bulk phase of the nano-host material in the form of a single atom; wherein, the nano-host material is platinum, rhodium, or iridium, and the corresponding metal salt is platinum acetylacetonate, rhodium acetylacetonate, or iridium acetylacetonate; the rare earth element is lanthanum, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, or lutetium, and the corresponding metal salt is acetylacetonate; Different nanomaterials can be synthesized by controlling the mixing ratio of sodium nitrite and potassium nitrite and adjusting the holding temperature of different metal salts.

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