Selenium-based functional composite material and preparation method and application thereof

Abstract

The application discloses a selenium-based functional composite material and a preparation method and application thereof, and belongs to the technical field of functional materials. The selenium-based functional composite material is a core-shell structure, the shell layer of the core-shell structure is carbon, and the selenium-based functional composite material is coated with copper selenide. The selenium-based functional composite material prepared by the application can be used as an electromagnetic wave absorber, and has excellent electromagnetic wave absorption performance. The maximum reflection loss value can reach -74 dB, and the frequency band width with a reflection loss value less than -10 dB can reach 5.5 GHz.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of selenium-based functional composite materials, and particularly belongs to a selenium-based functional composite material, a preparation method thereof and application. BACKGROUND

[0002] Electromagnetic wave absorbing materials play an increasingly important role in various fields such as wireless communication, electromagnetic interference, radar stealth technology, etc. In these applications, people hope to find functional materials that can effectively absorb or reflect electromagnetic waves in a specific frequency range. Therefore, electromagnetic wave absorbing materials are of great significance for improving the performance of communication systems, protecting sensitive devices from electromagnetic interference, and application in military and stealth technology. The research of electromagnetic wave absorbing materials aims to find materials with light weight, strong absorption, wide absorption frequency band, etc.

[0003] Selenides are widely used in electronics, semiconductor devices, thermoelectricity, sensors, etc. due to their unique chemical, optical and electrical properties. It is also important that selenium-based materials show broad application prospects in the field of electromagnetic wave absorption due to their inherent electronic transport ability and dielectric properties. In order to adjust the inherent dielectric properties and electromagnetic response ability of selenium-based composite materials, morphology control and element design are effective ways to improve the electromagnetic absorption performance of selenium-based composite materials. Therefore, the present application uses copper-based metal organic framework materials to prepare selenium-based functional composite materials and studies their electromagnetic wave absorption performance. SUMMARY

[0004] The present application aims to provide a selenium-based functional composite material, a preparation method thereof and application, which overcomes the shortcomings of the prior art.

[0005] To solve the above problems, the technical scheme adopted by the present application is as follows:

[0006] A selenium-based functional composite material is of core-shell structure, the shell layer of the core-shell structure is carbon, and the shell layer is coated with copper selenide.

[0007] A method for preparing a selenium-based functional composite material comprises mixing a copper source and selenium powder uniformly according to a mass ratio, then heating at 400-600 DEG C under an inert gas atmosphere containing hydrogen for 5h, and obtaining the selenium-based functional composite material after cooling.

[0008] The copper source is a copper-based metal organic framework material.

[0009] The preparation method of the copper-based metal organic framework material comprises mixing a copper ion-containing methanol solution with a volume fraction of 3.5mmol / 100mL and a 1,3,5-benzene tricarboxylic acid-containing methanol solution with a volume fraction of 2mmol / 100mL according to a volume ratio of 1:1, then uniformly mixing, then standing for aging for 12h, then washing and drying the obtained solid to obtain the copper-based metal organic framework material.

[0010] The prepared selenium-based functional composite material can be used as an electromagnetic wave absorber.

[0011] Compared with the prior art, the implementation effects of the present application are as follows:

[0012] 1. The present application directly synthesizes a selenium-based functional composite material by using a copper-based metal organic framework material and selenium powder, and the synthesis method is simple; during the heating process, the selenium powder forms steam, the copper-based metal organic framework material is degraded and reduced, a core-shell structure with a carbon shell is formed, and the shell is filled with copper selenide.

[0013] 2. The prepared selenium-based functional composite material can be used as an electromagnetic wave absorber, and has excellent electromagnetic wave absorption performance, the maximum reflection loss value can reach-74 dB, and the frequency bandwidth with a reflection loss value less than-10 dB can reach 5.5 GHz. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 The x-ray diffraction pattern of the prepared selenium-based functional composite material of the present application;

[0015] Figure 2 The scanning electron microscope photos of the selenium-based functional composite materials of Examples 1-3;

[0016] Figure 3 The transmission electron microscope photo of the selenium-based functional composite material of Example 3;

[0017] Figure 4 The X-ray photoelectron spectrogram of the selenium-based functional composite material of Example 3;

[0018] Figure 5 The electromagnetic parameter diagram of the selenium-based functional composite materials of Examples 1-3;

[0019] Figure 6 The electromagnetic wave loss diagram of the selenium-based functional composite materials of Examples 1-3;

[0020] Figure 7 The crystal structure of Cu2Se nanoparticles in the selenium-based functional composite material of Example 3. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0022] The selenium-based functional composite prepared in the application is characterized by using the following test conditions: the crystal structure is characterized by an X-ray diffractometer (XRD, LABX XRD-6000); the morphology and microstructure are observed by a scanning electron microscope (SEM, S4800) and a transmission electron microscope (TEM, JEOL-2010); the chemical environment of elements is identified by X-ray photoelectron spectroscopy (XPS, Thermo ESCALAB250XI); the selenium-based functional composite is mixed with paraffin at a mass ratio of 1:1 to prepare a test sample, and the electromagnetic parameters are measured by a vector network analyzer; and the reflection loss value of the selenium-based functional composite can be calculated by the following formula:

[0023]

[0024] The volume percentage of H2 in the protective gas H2 / Ar used in the preparation of the selenium-based functional composite powder is 6%, and of course it can also be selected between 4%-8% according to the situation.

[0025] Example 1

[0026] Cu(NO3)2·3H2O (3.5 mmol) was added to 100 mL of a methanol solution and magnetically stirred to obtain solution A; 1,3,5-benzenetricarboxylic acid (2 mmol) was added to 100 mL of a CH3OH solution and magnetically stirred to obtain solution B; then, solution B was added dropwise to 100 mL of a CH3OH solution and magnetically stirred for 10 minutes, and after aging for 12 hours, the copper-based metal organic framework material was obtained after being washed with methanol for 3 times and vacuum dried.

[0027] The copper-based metal organic framework material was mixed with Se powder at a mass ratio of 1:3, and then the mixed powder was placed in a tube furnace and annealed at 400°C for 5h in H2 / Ar gas. Finally, the black selenium-based functional composite powder was prepared, marked as Cu2Se@C-400, and the scanning electron microscope photograph thereof is shown in Figure 2 (a).

[0028] Example 2

[0029] Cu(NO3)2·3H2O (3.5 mmol) was added to 100 mL of a methanol solution and magnetically stirred to obtain solution A; 1,3,5-benzenetricarboxylic acid (2 mmol) was added to 100 mL of a CH3OH solution and magnetically stirred to obtain solution B; then, solution B was added dropwise to 100 mL of a CH3OH solution and magnetically stirred for 10 minutes, and after aging for 12 hours, the copper-based metal organic framework material was obtained after being washed with methanol for 3 times and vacuum dried.

[0030] The copper-based metal organic framework material is mixed with Se powder at a mass ratio of 1:3, and then the mixed powder is placed in a tube furnace and annealed at 500 DEG C for 5h in H2 / Ar gas. Finally, a black selenium-based functional composite powder is prepared, marked as Cu2Se@C-500, and the scanning electron microscope photograph thereof is as shown in Figure 2 (b).

[0031] Example 3

[0032] Cu(NO3)2.3H2O (3.5mmol) is added into 100mL of a methanol solution to obtain solution A; 1,3,5-benzene tricarboxylic acid (2mmol) is added into 100mL of a CH3OH solution to obtain solution B; solution B is then added dropwise into 100mL of a CH3OH solution and magnetically stirred for 10 minutes; after aging for 12 hours, the copper-based metal organic framework material is obtained after being washed with methanol for 3 times and vacuum dried.

[0033] The copper-based metal organic framework material is mixed with Se powder at a mass ratio of 1:3, and then the mixed powder is placed in a tube furnace and annealed at 600 DEG C for 5h in H2 / Ar gas. Finally, a black selenium-based functional composite powder is prepared, marked as Cu2Se@C-600, and the scanning electron microscope photograph thereof is as shown in Figure 2 (c), and the transmission electron microscope photograph is as shown in Figure 3 .

[0034] As can be seen from the results in the drawings of the specification Figures 1-7 , the selenium-based functional composite material is prepared, wherein Figure 1 the crystal face positions of Cu2Se@C-400, Cu2Se@C-500 and Cu2Se@C-600 in the specification are the same as those of Cu2Se (JCPDS No. 06-0680), and 2-x the selenium-based functional composite material has a core-shell structure. Figures 2-3 As can be clearly seen from the scanning electron microscope and the transmission electron microscope in the specification, the selenium-based functional composite material has a core-shell structure. Figures 2-3 As can be seen from the results in the drawings of the specification , the selenium-based functional composite material has irregular granular shape, and the transmission electron microscope photograph of the selenium-based functional composite material prepared in Example 3 shows that it has a core-shell structure, the thickness of the shell layer is about 5nm, the particle size of the core-shell structure is in the range of 50-200nm, and the core-shell structure is in a dispersed and accumulated state.

[0035] In the high-resolution Cu 2p orbit Figure 4 in (a), the peaks at 952.0eV and 932.1eV belong to Cu2p1 / 2 and Cu 2p3 / 2 respectively; for the high-resolution spectrum of Se 3d orbit Figure 4In (b), the peaks at 55.3 eV and 54.4 eV are attributed to Se 3d3 / 2 and Se 3d5 / 2, respectively; the peak of the C 1s orbital appears at 284.6 eV, and the peak at 285.9 eV is attributed to the C atoms in CC / C=C and CO. Figure 4 (c) in the middle.

[0036] and Figures 5-6 As can be seen, from Cu2Se@C-400 to Cu2Se@C-600 composite materials, the absorption intensity (electromagnetic wave loss value RL) and the performance of RL less than -10dB are both improved; for Cu2Se@C-500 composite material, when the thickness is 2.0mm, the minimum RL value at 12.4GHz is -12.2dB, and the bandwidth of RL less than -10dB in the 10.8GHz-13.4GHz range is 2.6GHz. Figure 6 (b)]; When the annealing temperature is increased to 600℃, the resulting Cu2Se@C-600 composite material exhibits the best electromagnetic wave absorption capability, such as Figure 6 As shown in (c), when the thickness is 2.0 mm, the minimum RL value of Cu2Se@C-600 can reach -74.3 dB. When the matching thickness is adjusted to 2.3 mm, the bandwidth of Cu2Se@C-600 with an RL value less than -10 dB is 5.5 GHz (7.7 GHz to 13.2 GHz), covering the entire X-band. These results demonstrate that selenium-based functional composite materials prepared based on copper-based metal-organic frameworks show great application potential in the field of electromagnetic absorption.

[0037] Cu2Se@C-600, derived from copper-based metal-organic frameworks, exhibits excellent electromagnetic wave absorption performance. Regarding polarization loss, interfacial polarization and dipole polarization are the main components. In the Cu2Se@C-600 composite material, the selenium-based functional composite material contains abundant Cu2Se / C heterojunction interfaces. After selenization pyrolysis treatment, the carbon layer tightly encapsulates Cu2Se nanoparticles, forming a semiconductor carbon-type contact region. Due to the difference in work function between Cu2Se nanoparticles and carbon, an internal electric field can be formed to provide interfacial polarization. When high-frequency electromagnetic waves are applied, the movement of charges at the heterojunction interface induces a "macroscopic" dipole moment, thereby dissipating electromagnetic energy. For Cu2Se nanoparticles, Cu... 1+ and Cu 2+ Mixed valence states ( Figure 7 The non-uniform distribution of intrinsic charge within the crystal generates natural polarization characteristics, promoting the establishment of dipole polarization. At the same time, defects exist in the micro-strained Cu2Se nanoparticles, providing dipole polarization sites. As a result, the prepared selenium-based functional composite material achieves good electromagnetic wave absorption performance.

[0038] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely exemplary of the principles and application of the present application. Numerous modifications and adaptions can be effected without departing from the spirit and scope of the present application, which is not limited to the exact construction and arrangement described. It is intended, therefore, to cover all modifications and adaptions that fall within the scope of the claims and their equivalents.

Claims

1. A method for preparing a selenium-based functional composite material, characterized by, A copper source and selenium powder are mixed uniformly according to a mass ratio, and then heated at 400-600 DEG C for 5h under an inert gas atmosphere containing hydrogen, and after cooling, a selenium-based functional composite material is obtained, the selenium-based functional composite material is a core-shell structure, the shell layer of the core-shell structure is carbon, and the copper selenide is coated in the shell layer.

2. The method for preparing selenium-based functional composite materials according to claim 1, characterized in that, The copper source is a copper-based metal organic framework material.

3. The method of claim 2, wherein the method is characterized by, A preparation method of the copper-based metal organic framework material is as follows: a methanol solution containing copper ions 3.5 mmol / 100 mL and a methanol solution containing 1,3,5-benzene tricarboxylic acid 2 mmol / 100 mL are mixed uniformly according to a volume ratio of 1:1, then aged for 12h, and then the obtained solid is washed and dried to obtain the copper-based metal organic framework material.

4. The method for preparing selenium-based functional composite materials according to claim 1, characterized in that, The selenium-based functional composite material is used as an electromagnetic wave absorber.

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