Silver / transition metal oxoacid heterojunction nanomaterial, preparation method and application

Abstract

The application relates to the technical field of composite heterojunction materials, and discloses a silver / transition metal oxyacid heterojunction nanomaterial, the chemical expression of the nanomaterial being Ag / Ag x M y O z .nH2O, the surface of the nanomaterial being decorated with silver nanoparticles. The method comprises the following steps: placing silver metal electrode pieces on both sides of a reaction container, placing a transition metal target in the center of the reaction container; injecting high-purity deionized water into the reaction container and making the surface of the target be submerged; under the induction of an electric field, carrying out liquid-phase laser ablation reaction on the transition metal target for 30 min to obtain a reaction solution containing the transition metal target; collecting the reaction solution containing the transition metal target in a new container and standing for more than two weeks until white precipitates appear in the reaction solution, thereby obtaining the Ag / Ag x M y O z .nH2O heterojunction nanomaterial. The method is simple and convenient to operate, does not need to add other chemical reagents in the production process, is more environmentally friendly compared with a hydrothermal chemical method, and is simple and convenient, so the method is used to obtain the structural material for the first time.

Description

Technical Field

[0001] This invention relates to the field of composite heterojunction materials technology, specifically to a silver / transition metal oxometalate heterojunction nanomaterial, its preparation method, and its application. Background Technology

[0002] Plasma attachment to semiconductor materials to construct heterojunctions can enhance the optical and electrical properties of materials through mechanisms such as localized surface plasmon resonance (LSPR), which strengthens light absorption and scattering, localized electromagnetic fields, hot carrier injection, and thermal effects. However, current strategies for attaching plasma to semiconductor nanostructures primarily involve first preparing semiconductor nanomaterials using wet chemical methods with various chemical reagents, and then adding noble metal-containing chemical reagents to the semiconductor suspension to obtain a noble metal / semiconductor composite structure. However, hydrothermal reactions typically require the addition of large amounts of chemical reagents, resulting in significant pollution and complex operational procedures.

[0003] Chinese invention patent (application number: 202010108449.5) discloses a nanocomposite material based on a phosphomolybdenum disulfide polyoxometalate, its preparation method, an aptamer sensor, and its electrode. The nanocomposite material of this invention comprises carbon, molybdenum disulfide nanosheets, and silver-containing nanoparticles; the nanocomposite material is obtained by calcining a silver-doped phosphomolybdenum disulfide polyoxometalate, wherein the silver-doped phosphomolybdenum disulfide polyoxometalate is obtained by reacting a silver source, phosphomolybdic acid, and thioacetamide. This nanocomposite material has a high specific surface area and strong biocompatibility. The electrochemical sensor constructed from this nanocomposite material has a low detection limit when used to detect bisphenol A (BPA), and exhibits high selectivity, good stability and reproducibility, excellent renewability, and applicability in different environments. However, this method involves a hydrothermal reaction followed by high-temperature calcination, resulting in harsh reaction conditions. This invention proposes a convenient, chemical-requiring, and simple reaction method for noble metal / transition metal oxometalate heterostructure nanomaterials. Ag / Ag was obtained using this method. x M y O z A heterojunction nanostructure was discovered, and it was found to be a gas-sensitive sensor material with good response to hydrogen. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, the present invention aims to provide a silver / transition metal oxometalate heterostructure nanomaterial, its preparation method and application.

[0005] On one hand, the present invention provides a silver / transition metal oxometalate heterostructure nanomaterial, wherein the chemical formula of the nanomaterial is Ag / Ag x M y O z·nH2O, wherein the surface of the nanomaterial is modified with silver nanoparticles, where M is a transition metal, x is the number of Ag elements, y is the number of transition metals, z is the number of oxygen elements, and n is the number of water molecules.

[0006] Preferably, the nanomaterial has a diameter of 1 nm to 900 nm and a length of 1 μm to 1000 μm.

[0007] On the other hand, the present invention provides a method for preparing silver / transition metal oxometalate heterostructure nanomaterials, comprising the following steps:

[0008] Silver metal electrode sheets are placed on both sides of the reaction vessel, and the transition metal target is placed in the center of the reaction vessel.

[0009] Deionized water is injected into the reaction vessel and submerges the surface of the transition metal target.

[0010] The transition metal target was subjected to liquid-phase laser ablation under electric field induction to obtain a reaction solution containing the transition metal target.

[0011] The reaction solution containing the transition metal target is collected in a new container and allowed to stand for at least two weeks until a white precipitate appears in the reaction solution, thus obtaining Ag / Ag. x M y O z Heterojunction nanomaterials.

[0012] Preferably, the purity of the silver metal electrode sheet is 99%~99.999%, and the purity of the transition metal target is 99%~99.999%.

[0013] Preferably, the deionized water covers the surface of the transition metal target by 2mm-15mm.

[0014] Preferably, the conductivity of the deionized water is 15 MΩ-30 MΩ.

[0015] Preferably, the parameters of the laser ablation are: wavelength of 355nm or 532nm, frequency of 1Hz to 10Hz, and energy of 50mJ to 850mJ / pulse.

[0016] Preferably, the reaction time is 30 min to 2 h.

[0017] Preferably, the voltage of the electric field is 5V-180V.

[0018] Furthermore, the present invention also discloses the application of the aforementioned silver / transition metal oxometalate heterojunction nanomaterial in gas sensors.

[0019] The silver / transition metal oxometalate heterostructure nanomaterial, its preparation method, and its application described in this invention have the advantages of simple and convenient operation, requiring no additional chemical reagents during production, making it more environmentally friendly and convenient compared to hydrothermal chemical methods, and enabling one-step synthesis of Ag / Ag through laser ablation. x M y O z The reaction using ·nH₂O is simple and represents the first time this method has been used to obtain this type of structural material. This method is also a general approach, allowing the target material to be replaced with other metal targets to obtain noble metal / transition metal oxometalate heterostructure micro / nanostructure materials. Attached Figure Description

[0020] Figure 1 It is the Ag / Ag2Mo3O prepared in Example 1 of this invention. 10 • SEM image of 1.8H2O heterojunction nanomaterial;

[0021] Figure 2 It is the Ag / Ag2Mo3O prepared in Example 1 of this invention. 10 ·TEM image of 1.8H2O heterojunction nanomaterial and corresponding Ag, Mo, and O elemental distribution diagrams;

[0022] Figure 3 It is the Ag / Ag2Mo3O prepared in Example 1 of this invention. 10 XRD pattern of 1.8H2O heterojunction nanomaterial;

[0023] Figure 4 It is the Ag / Ag2Mo3O prepared in Example 1 of this invention. 10 • Photocurrent test results of 1.8H2O heterojunction nanomaterials;

[0024] Figure 5 The Ag / Ag2Mo3O of the present invention 10 • Schematic diagram of the apparatus for preparing 1.8H2O heterojunction nanomaterials. Detailed Implementation

[0025] like Figures 1-3 As shown, this embodiment discloses a silver / transition metal oxometalate heterostructure nanomaterial, the chemical formula of which is Ag / Ag. x M y O z The nanomaterial is modified with silver nanoparticles, where M is a transition metal, x is the amount of Ag, y is the amount of transition metal, z is the amount of O, and n is the amount of H2O. The nanomaterial has a diameter of 2nm-900nm and a length of 2μm-1000μm.

[0026] In this invention, M can represent a target material composed of other transition metals such as molybdenum, vanadium, tungsten, niobium, tantalum, and titanium, meaning the resulting nanomaterial can be Ag / Ag. x Mo y O z ·nH2O、Ag / Ag x V y O z ·nH2O、Ag / Ag x W y O z ·nH2O、Ag / Ag x Nb y O z ·nH2O、Ag / Ag x Ti y O z ·nH2O, etc.

[0027] In this invention, Ag / Ag is prepared using a molybdenum target as an example. x Mo y O z • nH2O heterojunction nanomaterials, wherein the values ​​of x, y, z and n may vary slightly depending on the card library and laser parameters, as detailed in the following examples. Example 1

[0028] like Figure 5 As shown, this embodiment provides a method for preparing silver / transition metal oxometalate heterostructure nanomaterials, including the following steps:

[0029] S1: Place the silver metal electrode sheets (99.99% purity) on both sides of the reaction vessel, and place the molybdenum target (99.99% purity) in the center of the reaction vessel;

[0030] S2: Inject high-purity deionized water (conductivity 18MΩ) into the reaction vessel, ensuring it covers the molybdenum target surface by 2mm;

[0031] S3: Turn on the laser and DC reaction power supply, and perform liquid phase laser ablation reaction on the molybdenum target for 30 minutes under electric field induction (voltage 5V) to obtain a reaction solution containing the molybdenum target. The laser ablation parameters are: wavelength 532nm, frequency 10Hz, and energy 600mJ / pulse.

[0032] S4: Collect the reaction solution containing the molybdenum target in a new container and let it stand for 2 weeks until a white precipitate appears in the reaction solution, thus obtaining Ag / Ag2Mo3O. 10 • 1.8H2O heterojunction nanomaterials. The entire synthesis method requires no additional chemical reagents and no multiple reaction steps, making it more convenient and environmentally friendly compared to existing methods.

[0033] Figure 1This embodiment shows Ag / Ag2Mo3O 10 • SEM image of 1.8H2O heterojunction nanomaterial. Figure 1 The middle left figure is Ag / Ag2Mo3O 10 • Low-magnification SEM image of the 1.8H2O heterojunction nanomaterial; the right image is a high-magnification image. As shown in the left image, Ag / Ag2Mo3O 10 The 1.8H2O heterojunction nanomaterial is fibrous, with a high-density dislocation network. As shown in the right figure, the surface of the nanomaterial is modified with Ag particles.

[0034] Fibrous nanomaterials possess extremely high specific surface areas, meaning they can provide more gas adsorption sites. When gas molecules adsorb onto the material surface, they undergo physical or chemical interactions with the material, thereby altering its electrical properties (such as resistance or capacitance). This high specific surface area allows fibrous nanomaterials to more effectively adsorb target gas molecules, thus improving the sensitivity of sensors.

[0035] Fibrous nanomaterials typically possess excellent electrical properties, such as high conductivity and low resistance. This enables them to respond rapidly to electrical changes during gas adsorption and desorption, thus achieving rapid detection. The surface chemical properties of fibrous nanomaterials can be modulated through various methods, such as doping, surface modification, or compositing with other materials. These methods can alter the material's selectivity for specific gases, thereby improving the detection accuracy of sensors. Decorating the surface of metal oxide nanofibers with silver nanoparticles can significantly enhance their gas detection performance.

[0036] In summary, the fibrous nanomaterials prepared in this embodiment have important application value in gas sensors due to their unique physical and chemical properties. They can significantly improve the sensitivity, selectivity and stability of the sensors, while reducing operating temperature and energy consumption.

[0037] Figure 2 This embodiment shows Ag / Ag2Mo3O 10 ·TEM image of 1.8H2O heterojunction nanomaterial and corresponding Ag, Mo, and O elemental distribution diagrams. Figure (1) shows a single Ag / Ag2Mo3O nanomaterial. 10 ·1.8H2O heterojunction nanomaterial TEM morphology image. As can be seen from the figure, the surface of the nanomaterial is modified with many particulate materials. In the figure (1), the three figures on the right are the corresponding Ag, Mo and O element distribution diagrams. It can be seen that there are Ag, Mo and O elements in the long nanowires, and the particulate material contains only Ag element and no O element. It is silver nanoparticles. Therefore, the structure obtained is Ag2Mo3O modified with Ag particles. 10 • 1.8H2O nanostructure.

[0038] Figure 3 This embodiment shows Ag / Ag2Mo3O 10 The XRD pattern of the 1.8H2O heterojunction nanomaterial shows seven peaks. The highest diffraction intensity peak corresponds to the silicon substrate. The other six diffraction peaks are located at 11.25°, 13.40°, 28.26°, 35.15°, 38.07°, and 46.26°, respectively, corresponding to Ag2Mo3O. 10 ·1.8H2O (JCPDS No.39-0045) has (101), (200), (103), (501), (230), and (404) crystal planes. Example 2

[0039] This embodiment provides a method for preparing silver / transition metal oxometalate heterostructure nanomaterials, including the following steps:

[0040] Silver metal electrode sheets (99.9% purity) were placed on both sides of the reaction vessel, and a molybdenum target (99.9% purity) was placed in the center of the reaction vessel.

[0041] High-purity deionized water (conductivity 15 MΩ) was injected into the reaction vessel, covering the molybdenum target surface by 5 mm.

[0042] Turn on the laser and DC reaction power supply, and perform liquid phase laser ablation reaction on the molybdenum target for 50 min under the induction of electric field (voltage 150V) to obtain a reaction solution containing the molybdenum target. The laser ablation parameters are: wavelength 355nm, frequency 1Hz, and energy 50mJ / pulse.

[0043] The reaction solution containing the molybdenum target was collected in a new container and allowed to stand for 3 weeks until a white precipitate appeared in the reaction solution, thus obtaining Ag / Ag2Mo5O. 14 ·2H2O heterojunction nanomaterials. Example 3

[0044] This embodiment provides a method for preparing silver / transition metal oxometalate heterostructure nanomaterials, including the following steps:

[0045] Silver metal electrode sheets (99.0% purity) were placed on both sides of the reaction vessel, and a molybdenum target (99.0% purity) was placed in the center of the reaction vessel.

[0046] High-purity deionized water (conductivity 18 MΩ) was injected into the reaction vessel, covering the molybdenum target surface by 10 mm.

[0047] Turn on the laser and DC reaction power supply, and perform liquid phase laser ablation reaction on the molybdenum target for 1 hour under the induction of electric field (voltage 50V) to obtain a reaction solution containing the molybdenum target. The parameters of laser ablation are: wavelength 355nm, frequency 5Hz, and energy 300mJ / pulse.

[0048] The reaction solution containing the molybdenum target was collected in a new container and allowed to stand for 4 weeks until a white precipitate appeared in the reaction solution, thus obtaining Ag / Ag3Mo6O. 18 ·5H2O heterojunction nanomaterials. Example 4

[0049] This embodiment provides a method for preparing silver / transition metal oxometalate heterostructure nanomaterials, including the following steps:

[0050] Silver metal electrode sheets (99.9% purity) were placed on both sides of the reaction vessel, and a molybdenum target (99.9% purity) was placed in the center of the reaction vessel.

[0051] High-purity deionized water (conductivity 18 MΩ) was injected into the reaction vessel, covering the molybdenum target surface by 8 mm.

[0052] Turn on the laser and DC reaction power supply, and perform liquid phase laser ablation reaction on the molybdenum target for 1 hour under the induction of electric field (voltage 50V) to obtain a reaction solution containing the molybdenum target. The parameters of laser ablation are: wavelength 532nm, frequency 6Hz, and energy 350mJ / pulse.

[0053] The reaction solution containing the molybdenum target was collected in a new container and allowed to stand for 4 weeks until a white precipitate appeared in the reaction solution, thus obtaining Ag / Ag3Mo5O. 16 ·3H2O heterojunction nanomaterials. Example 5

[0054] This embodiment provides a method for preparing silver / transition metal oxometalate heterostructure nanomaterials, including the following steps:

[0055] Silver metal electrode sheets (99.99% purity) were placed on both sides of the reaction vessel, and a molybdenum target (99.99% purity) was placed in the center of the reaction vessel.

[0056] High-purity deionized water (conductivity 30MΩ) was injected into the reaction vessel, covering the molybdenum target surface by 12mm.

[0057] Turn on the laser and DC reaction power supply, and perform liquid phase laser ablation reaction on the molybdenum target for 1.5 hours under the induction of electric field (voltage 100V) to obtain a reaction solution containing the molybdenum target. The laser ablation parameters are: wavelength 532nm, frequency 3Hz, and energy 400mJ / pulse.

[0058] The reaction solution containing the molybdenum target was collected in a new container and allowed to stand for 5 weeks until a white precipitate appeared in the reaction solution, thus obtaining Ag / Ag3Mo3O. 12 ·4H2O heterojunction nanomaterials. Example 6

[0059] This embodiment provides a method for preparing silver / transition metal oxometalate heterostructure nanomaterials, including the following steps:

[0060] Silver metal electrode sheets (99.999% purity) were placed on both sides of the reaction vessel, and a molybdenum target (99.999% purity) was placed in the center of the reaction vessel.

[0061] High-purity deionized water (conductivity 20MΩ) was injected into the reaction vessel, covering the molybdenum target surface by 15mm.

[0062] Turn on the laser and DC reaction power supply, and perform liquid phase laser ablation reaction on the molybdenum target for 2 hours under the induction of electric field (voltage 180V) to obtain a reaction solution containing the molybdenum target. The laser ablation parameters are: wavelength 532nm, frequency 8Hz, and energy 850mJ / pulse.

[0063] The reaction solution containing the molybdenum target was collected in a new container and allowed to stand for 6 weeks until a white precipitate appeared in the reaction solution, thus obtaining Ag / Ag4Mo5O. 18 ·3H2O heterojunction nanomaterials.

[0064] Application Example 1

[0065] Ag / Ag2Mo3O prepared in Example 1 10 • Application of 1.8H2O heterojunction nanomaterials in gas sensors.

[0066] Ag / Ag2Mo3O 10 A gas sensor was fabricated using a 1.8H₂O heterojunction. The sensor was connected to an external circuit to capture changes in current or resistance signals. Its current response was tested in environments with different hydrogen concentrations to obtain... Figure 4 Data. Experiments show that Ag / Ag2Mo3O 10 The 1.8H2O heterojunction exhibits a significant current signal response to hydrogen. This gas sensor has a detection limit of 10 ppm for hydrogen at 350 degrees Celsius.

[0067] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention.

[0068] For those skilled in the art, various other corresponding changes and modifications can be made based on the technical solutions and concepts described above, and all such changes and modifications should fall within the protection scope of the claims of this invention.

Claims

1. A method for preparing silver / transition metal oxometalate heterostructure nanomaterials, characterized in that, Includes the following steps: Silver metal electrode sheets are placed on both sides of the reaction vessel, and the transition metal target is placed in the center of the reaction vessel. Deionized water is injected into the reaction vessel and submerges the surface of the transition metal target. The transition metal target is subjected to liquid-phase laser ablation reaction under the induction of electric field to obtain a reaction solution containing the transition metal target. The voltage of the electric field is 5V-180V. The parameters of the laser ablation are: wavelength of 355nm or 532nm, frequency of 1Hz~10Hz, and energy of 50mJ~850mJ / pulse. The reaction solution containing the transition metal target is collected in a new container and allowed to stand for at least two weeks until a white precipitate appears, thus obtaining Ag / Ag. x M y O z ·nH2O nanomaterials, where M is a transition metal, representing one of molybdenum, vanadium, tungsten, niobium, or titanium, x is the number of Ag elements, y is the number of transition metals, z is the number of oxygen elements, and n is the number of water molecules.

2. The method for preparing silver / transition metal oxometalate heterostructure nanomaterials according to claim 1, characterized in that, The purity of the silver metal electrode sheet is 99%~99.999%, and the purity of the transition metal target is 99%~99.999%.

3. The method for preparing silver / transition metal oxometalate heterostructure nanomaterials according to claim 1, characterized in that, The deionized water covers the surface of the transition metal target by 2mm-15mm.

4. The method for preparing silver / transition metal oxometalate heterostructure nanomaterials according to claim 1, characterized in that, The conductivity of the deionized water is 15 MΩ-30 MΩ.

5. The method for preparing silver / transition metal oxometalate heterostructure nanomaterials according to claim 1, characterized in that, The reaction time is 30 min to 2 h.

6. A silver / transition metal oxometalate heterostructure nanomaterial, characterized in that, The silver / transition metal oxometalate heterostructure nanomaterial is prepared using any one of claims 1-5, wherein the chemical formula of the nanomaterial is Ag / Ag. x M y O z ·nH2O, the surface of the nanomaterial is modified with silver nanoparticles.

7. The silver / transition metal oxometalate heterostructure nanomaterial according to claim 6, characterized in that, The nanomaterial has a diameter of 1nm-900nm and a length of 1μm-1000μm.

8. The application of the silver / transition metal oxometalate heterojunction nanomaterial according to any one of claims 6-7 in gas sensors.

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