A boronene@MOF two-dimensional nanosheet and a preparation method thereof, a gas sensor and an application thereof

Abstract

The present application relates to the technical field of gas sensing, and particularly relates to a boronene@MOF two-dimensional nanosheet, a preparation method thereof, a gas sensor and application, comprising the following steps: mixing a boron-containing multilayer layered substance, an organic ligand and an acid solution to obtain a mixed solution; and performing a solvothermal reaction treatment on the mixed solution to obtain a boronene@MOF two-dimensional nanosheet. Through the joint action of the organic ligand and the acid solution, the metal in the boron-containing multilayer layered substance is used as a metal source, so that the direct conversion from the boron-containing multilayer layered substance to the two-dimensional boronene@MOF heterostructure is realized. The preparation process is simple, the cost is greatly reduced, and the preparation process is efficient, so that the utilization and conversion of the elements in the boron-containing multilayer layered substance can be maximized. In addition, the boronene@MOF two-dimensional nanosheet prepared by the preparation method supports each other to construct a reasonable heterostructure, reduces the basic resistance of the composite material, and exhibits excellent NO2 gas sensing performance at room temperature.

Description

Technical Field

[0001] This invention relates to the field of gas sensing technology, and in particular to a borone@MOF two-dimensional nanosheet, its preparation method, gas sensor, and applications. Background Technology

[0002] Compared to bulk materials, the electronic components in two-dimensional materials are confined to a two-dimensional structure. This unique structural feature endows them with a variety of unconventional physicochemical properties. For example, borophenes possess superior properties such as mechanical flexibility, light transmittance, ultra-high thermal and electrical conductivity, one-dimensional nearly free electronic states, metallic Dirac fermions, and superconductivity, and have already shown great promise in many research fields, such as electronics / optoelectronics, catalysis, energy storage, and sensing. Currently, the preparation strategies for borophenes can be mainly divided into top-down and bottom-up approaches. The top-down approach has been favored by researchers due to its large-scale preparation and low requirements for experimental conditions, becoming the mainstream strategy for borophene preparation. However, its multi-step preparation process, lengthy experimental route, and waste liquid generated by selective etching of precursors and loss of metal elements in raw materials during the experimental process greatly increase the time and cost of preparation.

[0003] Metal-organic frameworks (MOFs) are a new type of porous material that self-assembles with organic ligands, using metal ions and metal clusters as nodes. Benefiting from their naturally large specific surface area, tunable pore structure, diverse metal composition, and modifiable end groups, they are considered ideal gas sensing materials. However, the linking of organic ligands and metal ions often results in MOFs having extremely high resistivity, significantly increasing the difficulty of monitoring resistance changes when exposed to target gases and limiting signal response and transmission.

[0004] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a borophene@MOF two-dimensional nanosheet, its preparation method, gas sensor and application, aiming to solve the problems of complex process and high cost of existing MOF / two-dimensional material composite materials.

[0006] The technical solution of the present invention is as follows:

[0007] A method for preparing borone@MOF two-dimensional nanosheets includes the following steps:

[0008] A boron-containing multilayered material, an organic ligand, and an acid solution are mixed to obtain a mixture.

[0009] The mixture was subjected to a solvothermal reaction to obtain borogenene@MOF two-dimensional nanosheets.

[0010] The preparation method of the boronene@MOF two-dimensional nanosheet, wherein the boron-containing multilayer substance is selected from one or more of AlB2, MgB2, FeAlB, MoAlB and WAlB.

[0011] The preparation method of the boronene@MOF two-dimensional nanosheet, wherein the organic ligand is selected from one or more of 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin, imidazole, trimesic acid, 2,5-dihydroxyterephthalic acid, terephthalic acid, oxalic acid and phthalic acid.

[0012] The preparation method of the boronene@MOF two-dimensional nanosheet, wherein the solute in the acid solution is selected from one or more of formic acid, hydrochloric acid, acetic acid and sulfuric acid.

[0013] The preparation method of the boronene@MOF two-dimensional nanosheet, wherein the mass ratio of the boron-containing multilayer substance to the organic ligand is 1:(1-8).

[0014] The preparation method of the boronene@MOF two-dimensional nanosheet, wherein the volume ratio of the solute in the acid solution to the solvent in the acid solution is (5-10):1.

[0015] The preparation method of the boronene@MOF two-dimensional nanosheet, wherein the temperature of the solvothermal reaction treatment is 150-200 DEG C, and the time of the solvothermal reaction treatment is 6-24 hours.

[0016] A boronene@MOF two-dimensional nanosheet is prepared by the preparation method of the boronene@MOF two-dimensional nanosheet.

[0017] A gas sensor comprises a ceramic sheet printed with interdigital electrodes, and a gas sensing sensitive layer arranged on the interdigital electrodes; the gas sensing sensitive layer is prepared from the boronene@MOF two-dimensional nanosheet.

[0018] The application of a gas sensor in a nitrogen dioxide detection device.

[0019] Beneficial effects: the application provides a boronene@MOF two-dimensional nanosheet, a preparation method thereof, a gas sensor and application, comprising the following steps: mixing a boron-containing multilayer material, an organic ligand and an acid solution to obtain a mixed solution; and performing a solvothermal reaction treatment on the mixed solution to obtain a boronene@MOF two-dimensional nanosheet. The application realizes the direct conversion of the boron-containing multilayer material to the two-dimensional boronene@MOF heterostructure by the combined action of the organic ligand and the acid solution and the use of the metal in the boron-containing multilayer material as a metal source. The preparation process is simple, greatly reduces the cost, and is efficient, and can maximize the utilization and conversion of the elements in the boron-containing multilayer material. In addition, the boronene@MOF two-dimensional nanosheet prepared by the preparation method supports each other to construct a reasonable heterostructure, reduces the basic resistance of the composite material, and exhibits excellent NO2 gas sensing performance at room temperature. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is a process flow diagram of the preparation method of the boronene@MOF two-dimensional nanosheet of the application;

[0021] Figure 2 It is an XRD graph of the boronene@Al-PMOF prepared in Example 1;

[0022] Figure 3 It is an XRD graph of the boronene@Al-PMOF prepared in Example 1 after etching and removing the MOF;

[0023] Figure 4 It is a SEM graph and a transmission electron microscope graph of the product when the reaction of AlB2 is performed for 0.5h, 3h and 12h and the boronene@Al-PMOF obtained by reacting for 12h in Example 1;

[0024] Figure 5 It is an XRD graph of the boronene@MIL-53 prepared in Example 2;

[0025] Figure 6 It is an XRD graph of the boronene@Mg-MOF-74 prepared in Example 3;

[0026] Figure 7 It is a room temperature sensing performance data graph of the gas sensing device of Example 4 for 10ppm NO2 at room temperature;

[0027] Figure 8 It is a selectivity test data graph of the gas sensing device of Example 4 for interfering gases. DETAILED DESCRIPTION

[0028] The application provides a boronene@MOF two-dimensional nanosheet and a preparation method, a gas sensor and an application thereof.

[0029] Those skilled in the art will understand that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0030] The conventional strategy for constructing MOF / two-dimensional material composites often needs to first etch two-dimensional materials and then self-assemble with MOFs, which is time-consuming and costly.

[0031] Based on this, as shown in the application provides a preparation method of boronene@MOF two-dimensional nanosheet, comprising the following steps: Figure 1

[0032] Step S10: mixing boron-containing multilayer material, organic ligand and acid solution to obtain a mixed solution;

[0033] Step S20: performing a solvothermal reaction treatment on the mixed solution to obtain a boronene@MOF two-dimensional nanosheet.

[0034] In this embodiment, by the joint action of the organic ligand and the acid solution, the metal in the boron-containing multilayer material is used as a metal source to realize the direct conversion of the boron-containing multilayer material to the two-dimensional boronene@MOF heterostructure. The preparation process is simple, greatly reduces the cost, and is efficient in the preparation process, which can maximize the utilization and conversion of elements in the boron-containing multilayer material. In addition, the boronene@MOF two-dimensional nanosheet prepared by the preparation method supports each other to construct a reasonable heterostructure, reduces the basic resistance of the composite material, and exhibits excellent NO2 gas sensing performance at room temperature.

[0035] ​Specifically, the present application promotes the dissolution of metal elements in the multilayer and the conversion to MOF by the mutual coordination of the organic ligand and the acid, thereby realizing the construction of MOF and two-dimensional substrate composite material; the preparation method adopts "one-pot method" one-step synthesis, which greatly reduces the time cost compared with the multi-step preparation of composite material, and avoids the loss of metal elements in the boron-containing multilayer compared with the strategy of etching and then self-assembly, realizes the maximization of metal element utilization and saves the cost and resource waste caused by the additional introduction of solvent waste liquid. In addition, in the process of in-situ construction of MOF / two-dimensional material heterojunction by using the preparation method, the two-dimensional material and the MOF are generated together, thereby being closely and uniformly compounded together, forming a three-dimensional sheet structure assembled by two-dimensional MOF nanosheets and two-dimensional material nanosheets, so that the prepared boronene@MOF two-dimensional nanosheet has faster response speed and higher response value for NO2.

[0036] In some embodiments, the boron-containing multilayer is selected from one or more of AlB2, MgB2, FeAlB, MoAlB, WAlB. The above boron-containing multilayer can be subjected to the joint action of the organic ligand and the acid solution, so that the metal in the boron-containing multilayer serves as a metal source, realizing the direct conversion from the boron-containing multilayer to the two-dimensional boronene@MOF heterostructure.

[0037] In a preferred embodiment, the boron-containing multilayer is AlB2.

[0038] In some embodiments, the organic ligand is selected from one or more of 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin, imidazole, trimesic acid, 2,5-dihydroxyterephthalic acid, terephthalic acid, oxalic acid, phthalic acid.

[0039] In a preferred embodiment, the organic ligand is 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin.

[0040] Specifically, the above organic ligand and the acid solution can play a mutual coordination role, so that the metal elements in the multilayer are dissolved and converted to MOF, thereby realizing the construction of MOF and two-dimensional substrate composite material.

[0041] In some embodiments, the solute in the acid solution is selected from one or more of formic acid, hydrochloric acid, acetic acid, sulfuric acid. The above acid can better play a synergistic role with the organic ligand, which is conducive to promoting the dissolution of metal elements in the multilayer and the conversion to MOF, thereby realizing the construction of MOF and two-dimensional substrate composite material.

[0042] In some embodiments, the mass ratio of the boron-containing multi-layered substance to the organic ligand is 1:(1-8). Controlling the mass ratio of the boron-containing multi-layered substance to the organic ligand within the above range, in combination with the one-pot synthesis process of boronene@MOF two-dimensional nanosheets, enables the two-dimensional material to be generated together with the MOF, so as to be closely and uniformly compounded together, thereby forming a three-dimensional sheet structure assembled by the two-dimensional MOF nanosheets and the two-dimensional material nanosheets, so that the material has a faster response speed and a higher response value for NO2.

[0043] In a preferred embodiment, the mass ratio of the boron-containing multi-layered substance to the organic ligand is 1:(1-3) or 1:(5-8) to satisfy all metal atom coordination as much as possible.

[0044] In some embodiments, the volume ratio of the solute in the acid solution to the solvent in the acid solution is (5-10):1. Reasonably controlling the concentration of the acid solution can maximize the utilization rate of metal elements and avoid excessive introduction of solvents to cause cost increase and resource waste.

[0045] In a preferred embodiment, the volume ratio of the solute in the acid solution to the solvent in the acid solution is 8:1 to etch the metal atoms in the boron-containing multi-layered substance as much as possible and not to inhibit the nucleation and growth of the MOF.

[0046] In some embodiments, the temperature of the solvothermal reaction treatment is 150-200°C, and the time of the solvothermal reaction treatment is 6-24h. Under the solvothermal reaction treatment conditions, the reaction can be promoted to occur in the forward direction and high-crystallinity MOF can be obtained, thereby obtaining boronene@MOF two-dimensional nanosheets.

[0047] In a preferred embodiment, the temperature of the solvothermal reaction treatment is 180°C, and the time of the solvothermal reaction treatment is 15h.

[0048] In some embodiments, after the solvothermal reaction treatment in step S20, the product is further subjected to centrifugation, washing, and drying treatment. Specifically, DMF and ethanol are used for washing, and the drying treatment is performed at a temperature of 60-80°C.

[0049] In addition, the application also provides a boronene@MOF two-dimensional nanosheet prepared by the preparation method of the boronene@MOF two-dimensional nanosheet.

[0050] In the embodiment, the boronene@MOF two-dimensional nanosheet is used to construct a reasonable heterostructure by mutual support, the basic resistance of the composite material is reduced, and excellent NO2 gas sensing performance is exhibited at room temperature. In the process of in-situ construction of the MOF / two-dimensional material heterojunction by using the preparation method, the two-dimensional material is generated together with the MOF, so as to be closely and uniformly compounded together, and a three-dimensional sheet structure composed of two-dimensional MOF nanosheets and two-dimensional material nanosheets is constructed, so that the prepared boronene@MOF two-dimensional nanosheet has a faster response speed and a higher response value for NO2. Moreover, the MOF / two-dimensional material composite material is prepared by using a simple solvothermal method, the method is simple, low in cost, and capable of realizing large-scale preparation, and meanwhile, the MOF / two-dimensional material composite material can be rapidly prepared.

[0051] In addition, the application further provides a gas sensor, which comprises a ceramic sheet printed with interdigital electrodes, and a gas sensing sensitive layer arranged on the interdigital electrodes; the gas sensing sensitive layer is prepared from the boronene@MOF two-dimensional nanosheet.

[0052] In the embodiment, the boronene@MOF two-dimensional nanosheet is used as a gas sensing sensitive layer of a gas sensor, and the high porosity and large specific surface area of the MOF and the enhanced electron transfer of the composite in the gas sensing process after the boronene is compounded are beneficial, so that the gas sensor can quickly respond and recover at room temperature, and has a wide application prospect in the detection of NO2. Moreover, the gas sensor has a simple preparation process, a small size, and a material easy to form a film, and is easy to realize commercial application.

[0053] In some embodiments, the thickness of the gas sensing sensitive layer is 1.5 mm-4 mm.

[0054] Meanwhile, the application further provides an application of the gas sensor in a nitrogen dioxide detection device.

[0055] The following further examples are used to further illustrate the application. It should also be understood that the following examples are only used to further illustrate the application, and cannot be understood as limiting the protection scope of the application, and some non-essential improvements and adjustments made by the person skilled in the art according to the above content of the application all belong to the protection scope of the application.

[0056] Example 1

[0057] The embodiment provides a boronene@Al-PMOF, and the preparation steps are as follows:

[0058] Take AlB2 and 5,10,15,20-tetra(4-carboxyphenyl)porphyrin (TCPP) powder with a mass ratio of 1:2 into the polytetrafluoroethylene liner of the reaction kettle, add DMF / formic acid mixed solvent with a mass ratio of 7:1 to make it fully dispersed, then transfer the reaction kettle to the oven for solvothermal reaction at 180℃ for 12h. After natural cooling, centrifugal collection of the product, washing with DMF and ethanol respectively, and drying in the 60℃ oven, it is recorded as boronene@Al-PMOF.

[0059] The boronene@Al-PMOF prepared in this example is characterized, and the XRD pattern is as shown in Figure 2 The diffraction peaks of the material correspond to the MOF fitting peaks, proving the occurrence of the reaction and the successful preparation of the corresponding MOF.

[0060] The boronene@Al-PMOF prepared in this example is etched to remove the MOF, and then characterized, and the XRD pattern is as shown in Figure 3 Proving the existence of boronene.

[0061] The AlB2, the products at 0.5h, 3h, 12h of the reaction, and the boronene@Al-PMOF obtained by reacting for 12h are characterized, and the SEM and transmission electron microscope images are as shown in Figure 4 The (a)-(d) in the figure are SEM images, and (e)-(h) are transmission electron microscope images; from Figure 4 It can be seen that (a) in the figure is the initial morphology of AlB2, showing a blocky morphology; (b) when the reaction is carried out to 0.5h, the surface of the sample is etched to produce many sharp tips; (c) when the reaction is further carried out to 3h, many MOF nanosheets grow on the surface of the sharp tips; (d) the nanosheets continuously grow to form a hollow tubular structure; from Figure 4 (e)-(h) in the figure, the nanosheets belong to MOF, and the corresponding with wrinkles belong to two-dimensional boronene nanosheets.

[0062] Example 2

[0063] This example provides a boronene@MIL-53, and the preparation steps are as follows:

[0064] Take AlB2 and terephthalic acid powder with a mass ratio of 1:2 into the polytetrafluoroethylene liner, add DMF / formic acid mixed solvent with a mass ratio of 7:1 to make it fully dispersed, then transfer the reaction kettle to the oven for solvothermal reaction at 180℃ for 15h. After natural cooling, centrifugal collection of the product, washing with DMF and ethanol respectively, and drying in the 60℃ oven, it is recorded as boronene@MIL-53.

[0065] The boronene@MIL-53 prepared in this example is characterized, and the XRD pattern is as shown in Figure 5As shown in the figure, the diffraction peaks of the material correspond to the MOF fitting peaks, proving the occurrence of the reaction and the successful preparation of the corresponding MOF.

[0066] Example 3

[0067] This example provides a boronene@Mg-MOF-74, which is prepared by the following steps:

[0068] AlB2 and 2,5-dihydroxyterephthalic acid powders with a mass ratio of 1:2 were weighed into a polytetrafluoroethylene liner, and a mixed solvent of DMF / formic acid with a mass ratio of 7:1 was added to disperse them sufficiently. Then the reaction kettle was transferred to an oven for solvothermal reaction at 180°C for 15h. After natural cooling, the product was collected by centrifugation, washed with DMF and ethanol respectively, and dried in a 60°C oven. The product was denoted as boronene@Mg-MOF-74.

[0069] The boronene@Mg-MOF-74 prepared in this example was characterized, and its XRD pattern is shown in Figure 6 As shown in the figure, the diffraction peaks of the material correspond to the MOF fitting peaks, proving the occurrence of the reaction and the successful preparation of the corresponding MOF.

[0070] Example 4

[0071] A gas sensor was prepared using the boronene@Al-PMOF prepared in Example 1, including the following steps:

[0072] The ceramic sheet printed with silver-palladium interdigital electrodes was sequentially ultrasonically cleaned in acetone, water and ethanol for 30min, and then dried in a 60°C oven for subsequent testing.

[0073] A certain amount of sample was dispersed in deionized water, and ultrasonicated to form a uniform solution of 10mg / mL.

[0074] 40μL of the uniformly dispersed sample was taken with a pipette and dropped on the silver-palladium interdigital electrodes to form a gas sensing sensitive layer with a thickness of about 2mm. After drying at room temperature, the test was carried out in air and nitrogen dioxide atmosphere, and the resistance change under different atmospheres was tested. The room temperature sensing performance data graph of the gas sensor device to 10ppm NO2 at room temperature is shown in Figure 7 As shown in the figure, the sample has good nitrogen dioxide gas sensing performance at room temperature. In the response process of 10ppm concentration of nitrogen dioxide, it shows a response time of 23s and a rapid recovery of 276s in air atmosphere. The selectivity test data graph of the sample to interfering gases is shown in Figure 8 As shown in the figure, the response value of the sample to nitrogen dioxide is 375%, which has very high selectivity compared with other gases.

[0075] In summary, the application provides a boronene@MOF two-dimensional nanosheet, a preparation method thereof, a gas sensor and an application, comprising the following steps: mixing a boron-containing multilayer substance, an organic ligand and an acid solution to obtain a mixed solution; and performing a solvothermal reaction treatment on the mixed solution to obtain a boronene@MOF two-dimensional nanosheet. Through the joint action of the organic ligand and the acid solution, the metal in the boron-containing multilayer substance is used as a metal source, so that the conversion from the boron-containing multilayer substance to the two-dimensional boronene@MOF heterostructure is realized. The preparation process is simple, the cost is greatly reduced, and the preparation process is efficient, so that the utilization and conversion of the elements in the boron-containing multilayer substance can be maximized. In addition, the boronene@MOF two-dimensional nanosheet prepared by the preparation method supports each other to construct a reasonable heterostructure, reduces the basic resistance of the composite material, and exhibits excellent NO2 gas sensing performance at room temperature.

[0076] It should be understood that the application of the application is not limited to the above examples, and those skilled in the art can make improvements or changes according to the above description, and all these improvements and changes shall belong to the protection scope of the appended claims of the application.

Claims

1. A method for preparing borophene@MOF two-dimensional nanosheets, characterized in that, Including the following steps: A boron-containing multilayered material, an organic ligand, and an acid solution are mixed to obtain a mixture. The mixture was subjected to a solvothermal reaction treatment to obtain borogenene@MOF two-dimensional nanosheets; The boron-containing multilayered material is selected from one or more of AlB2, MgB2, FeAlB, MoAlB, and WAlB; the organic ligand is selected from one or more of 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin, imidazole, pyromellitic acid, 2,5-dihydroxyterephthalic acid, terephthalic acid, oxalic acid, and phthalic acid.

2. The method for preparing borophene@MOF two-dimensional nanosheets according to claim 1, characterized in that, The solute in the acid solution is selected from one or more of formic acid, hydrochloric acid, acetic acid, and sulfuric acid.

3. The method for preparing borophene@MOF two-dimensional nanosheets according to claim 1, characterized in that, The mass ratio of the boron-containing multilayered material to the organic ligand is 1:(1-8).

4. The method for preparing borophene@MOF two-dimensional nanosheets according to claim 1, characterized in that, The volume ratio of the solute to the solvent in the acid solution is (5-10):

1.

5. The method for preparing borophene@MOF two-dimensional nanosheets according to claim 1, characterized in that, The temperature of the solvothermal reaction treatment is 150℃-200℃, and the time of the solvothermal reaction treatment is 6h-24h.

6. A borophene@MOF two-dimensional nanosheet, characterized in that, The borogenene@MOF two-dimensional nanosheets were prepared using the method described in any one of claims 1-5.

7. A gas sensor, characterized in that, It includes a ceramic sheet printed with interdigitated electrodes, and a gas sensing layer disposed on the interdigitated electrodes; the gas sensing layer is made of borene@MOF two-dimensional nanosheets as described in claim 6.

8. The application of the gas sensor as described in claim 7 in a nitrogen dioxide detection device.

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