A one-dimensional polymerized nitrogen chain, its preparation method and application

Abstract

This invention discloses a one-dimensional polymeric nitrogen chain, its preparation method, and its applications. The one-dimensional polymeric nitrogen chain is an allotrope of nitrogen and has an orthorhombic crystal structure. Cmc The 21-phase structure consists of infinite nitrogen chains extending along a one-dimensional direction, with bond types primarily N=N and N-N, exhibiting a typical serrated [-N=N-N=N-] chain framework. The preparation method involves nitrogen polymerization induced by laser heating under high pressure. In-situ Raman spectroscopy and synchrotron X-ray diffraction experiments characterized the product, confirming the formation of a novel one-dimensional polymerized nitrogen chain. Theoretical calculations indicate that this structure exhibits approximately 2.723 g / cm³ at ambient pressure. 3 It boasts high density and a high energy density of approximately 8.78 kJ / g. This makes it applicable to the field of all-nitrogen energy materials, laying the foundation for the widespread application of novel green high-energy materials.

Description

Technical Field

[0001] This invention belongs to the field of energetic materials technology, and relates to novel polymeric nitrogen, specifically to a novel one-dimensional polymeric nitrogen chain (1D-PN) and its preparation method. Background Technology

[0002] Polymeric nitrogen (PNi) is a class of high-energy-density materials formed by nitrogen atoms linked by covalent bonds. It has attracted considerable attention due to its preparation from nitrogen gas under high-pressure conditions and its ability to store large amounts of energy. Compared to traditional energetic materials with an energy density of 4.3 kJ / g, PNi exhibits a significantly higher energy density. For example, three-dimensional cubic deflection polymeric nitrogen (cg-N) has an energy density as high as 10.86 kJ / g, more than twice that of TNT (4.3 kJ / g). Furthermore, the decomposition product of PNi is only nitrogen gas, offering a significant advantage in terms of cleanliness and environmental friendliness. It is a novel all-nitrogen energy material with broad applications in high-energy green explosives, propellants, and other fields.

[0003] Currently known polymeric nitrogen can be classified into one-dimensional chain structures, two-dimensional layered structures, and three-dimensional network structures according to their dimensions. Three-dimensional polymeric nitrogen consists of three-coordinated nitrogen atoms cross-linked in three-dimensional space to form a dense framework, such as cubic structures (cg-N) and black phosphorus structures (BP-N).

[0004] Nature Mater In 2004, 3, 558–563, using nitrogen as a raw material and B or TiN as an endothermic material, cg-N with all single bonds was prepared for the first time at 110 GPa and 2000 K. Subsequently, it was successfully reproduced by direct heating of ζ-N.

[0005] Sci. Adv On June 9, 2020, 920617, it was first synthesized under conditions of 146 GPa and 2200 K, and the black phosphorus-type polymeric nitrogen (BP-N) was confirmed by synchrotron XRD and Raman spectroscopy.

[0006] Two-dimensional layered polymeric nitrogen consists of a three-coordinated nitrogen atom forming an ordered layered network in a plane. Experimentally reported examples include layered polymeric nitrogen (LP-N) and hexagonal layered polymeric nitrogen (HLP-N). Phys. Rev. Lett. LP-N was obtained at 125 GPa and 2000 K in 2014, 113, and 205502, coexisting with cg-N and amorphous nitrogen. Phys. Rev. Lett HLP-N was first synthesized and confirmed at approximately 250 GPa. (2019, 122, 066001) Summary of the Invention

[0007] This invention is the first to successfully synthesize one-dimensional chain-like polymeric nitrogen (1D-PN) under experimental conditions, and its structure was determined to be possessing [specific characteristics]. Cmc21-Symmetric Polymer Phase. This one-dimensional polymeric nitrogen chain is considered one of the most promising all-nitrogen energy materials due to its high energy density, low synthesis pressure, and potential structural tunability.

[0008] Based on the inventor's research findings, this invention provides a one-dimensional polymeric nitrogen chain. The one-dimensional polymeric nitrogen chain structure is a one-dimensional nitrogen chain, and the bond types in the nitrogen chain include NN and N=N, with NN and N=N alternating.

[0009] Furthermore, the crystal structure of the one-dimensional polymeric nitrogen chain is an orthorhombic crystal system. Cmc The 21 phases have the following lattice constants at 113 GPa: a = 3.4819 Å, b = 5.3087 Å, c = 4.9031 Å, α = β = γ = 90°.

[0010] The present invention also provides a method for preparing the above-mentioned one-dimensional polymeric nitrogen chain, the method comprising: heating nitrogen gas in a reaction chamber with a laser under conditions of ≥110 GPa, so that the nitrogen gas reacts under conditions of more than 2000 K to obtain the one-dimensional polymeric nitrogen chain.

[0011] Optionally, compressed nitrogen gas is loaded into the reaction chamber and then pressurized to a pressure of ≥110 GPa (preferably 110-150 GPa). Then, the nitrogen gas in the reaction chamber is heated by a laser, so that the nitrogen gas reacts at a condition of more than 2000 K to obtain the one-dimensional polymerized nitrogen chain.

[0012] Optionally, the reaction chamber is a transparent reaction chamber.

[0013] Optionally, the reaction is carried out within a diamond anvil cell (DAC) device, and the bottom of the reaction chamber of the DAC device is lined with an insulating layer. More optionally, the bottom of the reaction chamber of the DAC device is lined with an endothermic layer, and the endothermic layer is positioned above the insulating layer. The endothermic layer material is one of Pb, Al, and TiN. The laser wavelength is 1064 nm and the power is 50-100 W.

[0014] The novel one-dimensional polymeric nitrogen chain of this invention is an orthorhombic crystal system not previously reported. Cmc 21. Polymeric nitrogen phase, consisting of a one-dimensional zigzag chain composed of continuous N=N and NNN. The density of this one-dimensional polymeric nitrogen chain under normal pressure is 2.723 ± 0.005 g / cm³. 3 With an energy density of 8.78±0.05 kJ / g, it is a novel high-energy-density material (HDEM) with high energy density, low synthesis pressure, and potential structural adjustability. It can be applied in the field of all-nitrogen energy materials, laying the foundation for the widespread application of new green high-energy materials. Attached Figure Description

[0015] Figure 1 The image shows the Raman spectrum of the one-dimensional polymeric nitrogen chain synthesized in Example 1.

[0016] Figure 2 This is a crystal structure diagram of the one-dimensional polymeric nitrogen chain prepared in this invention.

[0017] Figure 3 The image shows the refined XRD pattern of the one-dimensional polymeric nitrogen chain Le Bail prepared in this invention.

[0018] Figure 4 The image shows the Raman spectrum of the one-dimensional polymeric nitrogen chain synthesized in Example 2.

[0019] Figure 5 The Raman spectrum of the one-dimensional polymeric nitrogen chain synthesized in Example 3 is shown.

[0020] Figure 6 The Raman spectrum of the one-dimensional polymeric nitrogen chain synthesized in Example 4 is shown.

[0021] Figure 7 The Raman spectrum of the one-dimensional polymeric nitrogen chain synthesized in Example 5 is shown. Detailed Implementation

[0022] Unless otherwise specified, the scientific and technical terms used in this article are intended for understanding by those skilled in the art.

[0023] This invention utilizes laser heating under high pressure to induce the breakage and recombination of N≡N triple bonds, gradually transforming them into an infinite chain structure composed of N=N and NN. Specifically, the reaction can be carried out using a diamond anvil cell. In a preferred embodiment, the laser coupling can be enhanced using endothermic materials such as Pb, Al, or TiN, or direct heating can be performed without the use of endothermic materials.

[0024] The following are implementation examples provided by the inventors. It should be noted that these embodiments are preferred examples, mainly used to understand the present invention, but the present invention is not limited to these embodiments. It should be pointed out that any processes not specifically described below are those that can be implemented or understood by those skilled in the art by referring to existing technology. Reagents or instruments whose manufacturers are not specified are considered to be conventional products that can be purchased commercially.

[0025] Example 1:

[0026] The preparation scheme of this embodiment is to assemble a diamond anvil cell (DAC) device. During the assembly process, NaCl pre-pressed into a thin sheet is first placed at the bottom of the sample chamber of the rhenium-sealed pad as an insulation layer. Then, a small piece of metallic lead Pb is filled on top of it as a heat-absorbing material, so that Pb covers approximately one-third of the bottom of the sample chamber.

[0027] To increase the nitrogen gas loading capacity, nitrogen was compressed to 200 MPa to form high-pressure nitrogen, which was then loaded into a diamond anvil reaction chamber equipped with a heating element. The pressure inside the reaction chamber was then increased to approximately 130 GPa, and the nitrogen was irradiated with a laser with a wavelength of 1064 nm and a power of 60 W to raise the temperature of the reaction zone to over 2000 K. The laser irradiation was then continued for 20 min to obtain the product.

[0028] The product was characterized by Raman spectroscopy and synchrotron X-ray diffraction. The Raman spectrum of the product was obtained by... Figure 1 It can be seen that nitrogen gas, after being heated under high pressure, reaches a depth of 373.4 cm. - ¹, 468.2 cm -1 587.1cm -1 and 648.7cm -1 A strong absorption peak appeared at that point.

[0029] Its crystal structure is predicted to be orthorhombic based on density functional theory (DFT) calculations. Cmc 21 phases, crystal structure as follows Figure 2 As shown. Using Cmc The cell parameters of the 21-phase phase were used to refine the XRD spectrum of the product using Le Bail, such as... Figure 3 As shown. The refined data fits the experimental data well, and at 9.3°, 13.2°, and 19.9°, values ​​belonging to the original data appear. Cmc The characteristic diffraction peaks of phase 21 confirm that the product is a one-dimensional polymeric nitrogen chain (1D-PN).

[0030] Furthermore, first-principles calculations showed that the product has a strength of approximately 2.723 g / cm³ at atmospheric pressure. 3 It has a high density and a high energy density of approximately 8.78 kJ / g.

[0031] Example 2: The difference between this embodiment and Embodiment 1 is that Al is filled into the diamond anvil cell (DAC) device as a heat-absorbing material and NaCl sheets are filled into the device as a heat-insulating layer.

[0032] During the reaction, nitrogen gas is compressed to 200 MPa to form high-pressure nitrogen gas, which is then loaded into the diamond anvil cell reaction chamber. At a pressure of approximately 130 GPa, the sample is irradiated with a laser with a wavelength of 1064 nm and a power of 60 W to raise the temperature of the reaction zone to over 2000 K. The laser irradiation is then continued for 20 min to obtain the product.

[0033] The product was characterized by Raman spectroscopy. Figure 4 It can be seen that nitrogen gas, after heating, reaches a depth of 371.5 cm. -1 466.8 cm -1 583.6 cm-1 and 642.1 cm -1 A strong absorption peak appeared at [location missing]. The Raman shift was basically consistent with that of Example 1, confirming that the product is a one-dimensional polymeric nitrogen chain (1D-PN).

[0034] Example 3: The difference between this embodiment and Embodiment 1 is that TiN is filled into the diamond anvil cell (DAC) device as a heat-absorbing material and NaCl sheets are filled into the device as a heat-insulating layer.

[0035] During the reaction, nitrogen gas is compressed to 200 MPa to form high-pressure nitrogen gas, which is then loaded into the diamond anvil cell reaction chamber. At a pressure of approximately 130 GPa, the sample is irradiated with a laser with a wavelength of 1064 nm and a power of 60 W to raise the temperature of the reaction zone to over 2000 K. The laser irradiation is then continued for 20 min to obtain the product.

[0036] The product was then characterized by Raman spectroscopy. Figure 5 It can be seen that nitrogen gas, after heating, reaches a depth of 368.4 cm. -1 460.5cm -1 580.6 cm -1 and 642.1 cm -1 A strong absorption peak appeared at the point, and the Raman shift was basically consistent with that of Example 1, confirming that the product is a one-dimensional polymeric nitrogen chain (1D-PN).

[0037] Example 4: The difference between this embodiment and Embodiment 1 is that NaCl sheets are filled inside the diamond anvil cell (DAC) device as an insulating layer, and no heat-absorbing material is added.

[0038] During the reaction, nitrogen gas is compressed to 200 MPa to form high-pressure nitrogen gas, which is then loaded into the reaction chamber of a diamond anvil cell. At a pressure of approximately 140 GPa, the sample is irradiated with a laser with a wavelength of 1064 nm and a power of 60 W to raise the temperature of the reaction zone to over 2000 K. The laser irradiation is then continued for 20 min to obtain the product.

[0039] The product was characterized by Raman spectroscopy. Figure 6 It can be seen that nitrogen gas, after heating, reaches a depth of 374.5 cm. -1 475.8 cm -1 586.7 cm -1 and 657.4 cm -1 A strong absorption peak appeared at the point, and the Raman shift was basically consistent with that of Example 1, confirming that the product is a novel one-dimensional polymeric nitrogen chain (1D-PN).

[0040] Example 5: The difference between this embodiment and Embodiment 1 is that TiN is filled into the diamond anvil cell (DAC) device as a heat-absorbing material and NaCl sheets are filled into the device as a heat-insulating layer.

[0041] During the reaction, nitrogen gas is compressed to 200 MPa to form high-pressure nitrogen gas, which is then placed in a diamond anvil cell with a heating element. The pressure inside the reaction chamber is approximately 115 GPa. The sample is then irradiated with a laser with a wavelength of 1064 nm and a power of 60 W to raise the temperature of the reaction zone to over 2000 K. The laser irradiation is then continued for 20 min to obtain the product.

[0042] The product was characterized by Raman spectroscopy. Figure 7 It can be seen that nitrogen gas, after heating, reaches a depth of 365.2 cm. -1 454.4 cm -1 577.3 cm -1 and 632.7 cm -1 A strong absorption peak appeared at the point, and the Raman shift was basically consistent with that of Example 1, confirming that the product is a one-dimensional polymeric nitrogen chain (1D-PN).

Claims

1. A one-dimensional polymeric nitrogen chain, characterized in that, The one-dimensional polymeric nitrogen chain structure is a one-dimensional nitrogen chain, and the bond types in the nitrogen chain include NN and N=N, with NN and N=N alternating.

2. The one-dimensional polymerized nitrogen chain according to claim 1, characterized in that, The crystal structure of the one-dimensional polymeric nitrogen chain is an orthorhombic crystal system. Cmc The 21 phases have the following lattice constants at 113 GPa: a = 3.4819 Å, b = 5.3087 Å, c = 4.9031 Å, α = β = γ = 90°.

3. The one-dimensional polymerized nitrogen chain according to claim 1, characterized in that, The density of the one-dimensional polymeric nitrogen chain under normal pressure is 2.723 ± 0.005 g / cm³. 3 The energy density is 8.78±0.05 kJ / g.

4. The method for preparing the one-dimensional polymeric nitrogen chain according to claim 1, characterized in that, The method includes heating nitrogen gas in the reaction chamber with a laser at a pressure of ≥110 GPa, so that the nitrogen gas reacts at a pressure of over 2000 K to obtain the one-dimensional polymerized nitrogen chain.

5. The method for preparing one-dimensional polymerized nitrogen chains according to claim 4, characterized in that, Compressed nitrogen gas is loaded into the reaction chamber and then pressurized to a pressure of ≥110 GPa (preferably 110-150 GPa). The nitrogen gas in the reaction chamber is then heated by a laser, so that the nitrogen gas reacts at a temperature of over 2000 K to obtain the one-dimensional polymerized nitrogen chain.

6. The method for preparing one-dimensional polymerized nitrogen chains according to claim 4, characterized in that, The reaction chamber is a transparent reaction chamber.

7. The method for preparing one-dimensional polymerized nitrogen chains according to claim 4, characterized in that, The reaction takes place within a diamond anvil cell (DAC) device, and the bottom of the reaction chamber of the DAC device is lined with an insulating layer.

8. The method for preparing one-dimensional polymerized nitrogen chains according to claim 6, characterized in that, The bottom of the reaction chamber of the diamond anvil cell (DAC) device is lined with a heat-absorbing layer, which is located above the insulation layer.

9. The method for preparing one-dimensional polymerized nitrogen chains according to claim 8, characterized in that, The heat-absorbing layer material is one of Pb, Al, and TiN.

10. The method for preparing one-dimensional polymerized nitrogen chains according to claim 4, characterized in that, The laser wavelength is 1064nm and the power is 50-100W.

11. The application of the one-dimensional polymeric nitrogen chain of claim 1 as an energetic material.

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