Metal / semiconductor / multimetallic oxyanion heterojunction micro-nano material, preparation method and application

Abstract

The application relates to the technical field of composite heterojunction materials, and discloses a metal / semiconductor / multimetallic oxyacid salt heterojunction micro-nano material, a preparation method and application, the chemical expression of the micro-nano material is A / A x O / A y (BO z ) m (OH) n , and the micro-nano material is a two-dimensional nanosheet structure. The preparation method comprises the following steps: placing metal A electrodes on both sides of a reaction container, placing metal B target material in the center of the reaction container, injecting deionized water into the reaction container and submerging the surface of the metal B target material, performing liquid-phase laser ablation reaction on the metal B target material under the induction of an electric field, collecting the metal A electrodes after reaction into a new container, and standing for more than 2 weeks until two-dimensional nanosheet material grows on the surface of the metal A electrodes, the two-dimensional nanosheet material is A / A x O / A y (BO z ) m (OH) n micro-nano material and the like. The method is simple and convenient to operate, and can obtain A / A x O / A y (BO z ) m (OH) n multistage heterojunction nano structure with excellent electrolytic water performance without any complex chemical additives and reaction steps.

Description

Technical Field

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

[0002] Electrochemical water splitting is a green, environmentally friendly, and efficient method for hydrogen production, involving two reactions: oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Due to the slow reaction kinetics of OER and HER, electrochemical water splitting often requires a higher potential than theoretically possible, resulting in significant energy loss. Currently, noble metals such as Pt and IrO2 have been proven to be effective electrocatalysts for OER and HER; however, the scarcity and high cost of these materials hinder their large-scale application.

[0003] Non-precious metal electrocatalytic materials have attracted widespread attention. Given the still unsatisfactory performance of single-component catalysts, combining two or more catalytic materials to construct heterostructures has become an effective strategy to improve catalyst activity. This not only allows for synergistic effects through electron redistribution at the interface by combining different components, but also enables the creation of new interfacial structures by altering the composition and crystal phase, achieving highly efficient overall water splitting catalysis. Numerous studies have shown that heterostructure catalysts exhibit competitive electrocatalytic performance for HER and OER.

[0004] Currently, the main construction strategies are hydrothermal and chemical vapor deposition methods. These methods involve complex reaction processes, usually requiring multiple steps, introducing a large number of chemical reagents, and cumbersome reaction procedures. They may also have limitations such as being unable to be scaled up on a large scale and not being able to obtain specific structures. Summary of the Invention

[0005] In order to solve the problems existing in the prior art, the present invention aims to provide a metal / semiconductor / polyoxometalate heterostructure micro / nanomaterial, its preparation method and application.

[0006] On one hand, the present invention provides a metal / semiconductor / polyoxometalate heterostructure micro / nanomaterial, wherein the chemical formula of the micro / nanomaterial is A / A x O / A y (BO z ) m (OH) n The micro / nanomaterial is a two-dimensional nanosheet structure, where A and B represent different metallic materials. x O represents a metal oxide, A y (BO z ) m (OH) n This indicates a polyoxometalate, where x, y, z, m, and n represent the number of the corresponding elements or ions.

[0007] On the other hand, the present invention also provides a method for preparing metal / semiconductor / polyoxometalate heterostructure micro / nanomaterials, comprising the following steps:

[0008] Metal A electrodes are placed on both sides of the reaction vessel, and metal B target material is placed in the center of the reaction vessel.

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

[0010] The metal B target was subjected to liquid-phase laser ablation reaction under the induction of an electric field;

[0011] The reacted metal A electrode is collected in a new container and left to stand for more than 2 weeks until a two-dimensional nanosheet material grows on the surface of the metal A electrode. This two-dimensional nanosheet material is Cu / Cu2O / Cu3(MoO4)2(OH)2 micro / nano material.

[0012] Preferably, the purity of the metal A electrode is 99% to 99.999%, and the purity of the metal B target is 99% to 99.999%.

[0013] Preferably, the deionized water covers the surface of the metal B target material 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, 532nm or 1064nm, 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] Preferably, the metal A electrode is an electrode sheet or a foam metal.

[0019] Furthermore, this invention also discloses the application of the aforementioned metal / semiconductor / polyoxometalate heterojunction micro / nanomaterials in electrocatalysts.

[0020] The present invention relates to a metal / semiconductor / polyoxometalate heterojunction micro / nanomaterial, its preparation method, and its application. The advantages of the present invention are that the method is simple and convenient to operate, and can obtain a multi-level heterojunction nanostructure with excellent water electrolysis performance without any complex chemical additives and reaction steps. Attached Figure Description

[0021] Figure 1 This is a SEM image of the Cu / Cu2O / Cu3(MoO4)2(OH)2 heterojunction micro / nano material of Example 1 of this invention;

[0022] Figure 2 This is the XRD pattern of the Cu / Cu2O / Cu3(MoO4)2(OH)2 heterojunction micro / nanomaterial of Example 1 of the present invention;

[0023] Figure 3 This is a graph showing the water electrolysis performance of the Cu / Cu2O / Cu3(MoO4)2(OH)2 heterojunction micro / nanomaterial of Example 1 of the present invention;

[0024] Figure 4 This is a structural diagram of the apparatus for preparing Cu / Cu2O / Cu3(MoO4)2(OH)2 heterojunction micro / nano materials according to Example 1 of the present invention. Detailed Implementation

[0025] like Figure 1 As shown, the present invention discloses a metal / semiconductor / polyoxometalate heterostructure micro / nanomaterial, the chemical formula of which is A / A. x O / A y (BO z ) m (OH) n The micro / nanomaterial is a two-dimensional nanosheet structure, where A and B represent different metallic materials, A x O represents a metal oxide, A y (BO z ) m (OH) n This indicates a polyoxometalate, where x, y, z, m, and n represent the quantities of the corresponding elements or ions. Two-dimensional nanosheet structures exhibit excellent performance in various electrocatalytic reactions due to their unique physicochemical properties.

[0026] Its main manifestations are as follows:

[0027] 1. High specific surface area and active sites

[0028] Two-dimensional nanosheet structures, with their ultrathin thickness and large specific surface area, can provide more active sites, thereby significantly improving the efficiency of electrocatalytic reactions. For example, two-dimensional nanosheets made of transition metal oxides and sulfides can effectively enhance the activity of the hydrogen evolution reaction (HER) and the oxygen reduction reaction (ORR) by increasing the number of active sites. In this embodiment, an oxide of Mo metal is used to effectively enhance the activity of the HER and ORR reactions.

[0029] 2. Excellent electronic transmission performance

[0030] The ultrathin structure of two-dimensional nanosheets helps to shorten the electron transport path and improve electron transport efficiency.

[0031] 3. Structural adjustability

[0032] Two-dimensional nanosheet structures can be regulated through various methods, including chemical doping, defect engineering, and heterostructure construction. These regulatory techniques can optimize the electronic structure and surface properties of materials, thereby improving their catalytic performance.

[0033] 4. Good stability and durability

[0034] Two-dimensional nanosheet structures typically possess high chemical stability and mechanical strength, enabling them to maintain good performance in complex electrochemical environments.

[0035] In summary, two-dimensional nanosheet structures exhibit great application potential in the field of electrocatalysts due to their high specific surface area, excellent electron transport performance, tunable structural characteristics, and good stability. These properties give them significant advantages in various electrocatalytic reactions such as the hydrogen evolution reaction (HER), oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and carbon dioxide reduction reaction (CO2RR).

[0036] In this embodiment, the electrode and target material can be Mo, V, Nb, Ta, W, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ag, Au, Ga, In, Sn, Sb, Pb, Bi, Ga, C, B, Ge, Te, etc., and the corresponding nanomaterials can be Cu / Cu2O / Cu3(MoO4)2(OH)2, Ni / NiO / NiMoO4, etc.

[0037] In this invention, we will use Cu as metal A and molybdenum as examples for illustration.

[0038] Example 1

[0039] Please refer to Figure 1 , Figure 2 as well as Figure 4 This embodiment discloses a method for preparing metal / semiconductor / polyoxometalate heterostructure micro / nanomaterials, including the following steps:

[0040] S1: Place copper electrode sheets with a purity of 99.99% on both sides of the reaction vessel, and place a molybdenum target with a purity of 99.99% in the center of the reaction vessel. The higher the purity, the lower the impurities contained in the micro-nano materials, and the higher the stability of the micro-nano materials.

[0041] S2: Inject high-purity deionized water with a conductivity of 18 MΩ into the reaction vessel, ensuring that the water level is 2 mm above the surface of the molybdenum target;

[0042] 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). Laser ablation parameters: wavelength 532nm, frequency 10Hz, energy 600mJ / pulse.

[0043] S4: Collect the reacted copper electrode sheet into a new container and let it stand for 2 weeks until green two-dimensional nanosheet material grows on the surface of the copper electrode sheet. This two-dimensional nanosheet material is the Cu / Cu2O / Cu3(MoO4)2(OH)2 micro / nano material. The entire synthesis method does not require the addition of additional chemical reagents or multiple reaction steps, making it more convenient and environmentally friendly than existing methods.

[0044] Figure 1 The SEM morphology of the Cu / Cu2O / Cu3(MoO4)2(OH)2 heterojunction micro / nanomaterial in this embodiment is shown. Figure 1 The left image shows a low-magnification SEM image of the Cu / Cu2O / Cu3(MoO4)2(OH)2 heterojunction micro / nanomaterial, while the right image shows a high-magnification image. As can be seen from the left image, the Cu / Cu2O / Cu3(MoO4)2(OH)2 heterojunction micro / nanomaterial exhibits a two-dimensional nanosheet structure.

[0045] Figure 2 The XRD pattern of the Cu / Cu2O / Cu3(MoO4)2(OH)2 heterostructure micro / nanomaterial in this embodiment is shown. As can be seen from the figure, the XRD pattern has eight peaks, located at 21.25°, 25.45°, 33.53°, 43.03°, 50.42°, 74.13°, 36.418°, and 61.344°. Specifically, 21.25°, 25.45°, and 33.53° correspond to the (101), (111), and (200) crystal planes of Cu3(MoO4)2(OH)2 (JCPDS No. 04-014-9758), respectively, while 43.03°, 50.42°, and 74.13° correspond to the (101), (111), and (200) crystal planes of Cu3(MoO4)2(OH)2 (JCPDS No. 04-014-9758), respectively. The (111), (200), and (220) crystal planes of No. 04-0836 are given, and 36.418° and 61.344° correspond to the (111) and (220) crystal planes of CuO (JCPDS No. 05-0667), respectively. As can be seen from the above, Cu / Cu2O / Cu3(MoO4)2(OH)2 heterostructure micro / nanomaterials were prepared in this embodiment.

[0046] Example 2

[0047] This embodiment discloses a method for preparing metal / semiconductor / polyoxometalate heterostructure micro / nanomaterials, including the following steps:

[0048] S1: Place copper electrode sheets with a purity of 99.99% on both sides of the reaction vessel, and place a molybdenum target with a purity of 99.99% in the center of the reaction vessel.

[0049] S2: Inject high-purity deionized water with a conductivity of 15 MΩ into the reaction vessel, ensuring that the water level is 5 mm above the surface of the molybdenum target;

[0050] S3: Turn on the laser and DC reaction power supply, and perform liquid phase laser ablation reaction on the molybdenum target for 50 minutes under electric field induction (voltage 150V). Laser ablation parameters: wavelength 355nm, frequency 1Hz, energy 50mJ / pulse.

[0051] S4: Collect the reacted copper electrode sheet into a new container and let it stand for 3 weeks until green two-dimensional nanosheet material grows on the surface of the copper electrode sheet. This two-dimensional nanosheet material is Cu / Cu2O / Cu3(MoO4)2(OH)2 micro / nano material.

[0052] Example 3

[0053] This embodiment discloses a method for preparing metal / semiconductor / polyoxometalate heterostructure micro / nanomaterials, including the following steps:

[0054] S1: Place 99.0% pure copper foam on both sides of the reaction vessel and place a 99.0% pure molybdenum target in the center of the reaction vessel.

[0055] S2: Inject high-purity deionized water with a conductivity of 25 MΩ into the reaction vessel, ensuring that the water level is 8 mm above the surface of the molybdenum target;

[0056] S3: Turn on the laser and DC reaction power supply, and perform liquid phase laser ablation reaction on the molybdenum target for 1 hour under electric field induction (voltage 50V). Laser ablation parameters: wavelength 355nm, frequency 5Hz, energy 300mJ / pulse.

[0057] S4: Collect the reacted copper electrode sheet into a new container and let it stand for 4 weeks until green two-dimensional nanosheet material grows on the surface of the foamed copper. This two-dimensional nanosheet material is Cu / Cu2O / Cu3(MoO4)2(OH)2 micro-nano material.

[0058] Example 4

[0059] This embodiment discloses a method for preparing metal / semiconductor / polyoxometalate heterostructure micro / nanomaterials, including the following steps:

[0060] S1: Place 99.9% pure copper foam on both sides of the reaction vessel and place a 99.9% pure molybdenum target in the center of the reaction vessel.

[0061] S2: Inject high-purity deionized water with a conductivity of 20 MΩ into the reaction vessel, ensuring that it covers the surface of the molybdenum target by 10 mm;

[0062] S3: Turn on the laser and DC reaction power supply, and perform liquid phase laser ablation reaction on the molybdenum target for 1.2 hours under electric field induction (voltage 180V). Laser ablation parameters: wavelength 532nm, frequency 6Hz, energy 350mJ / pulse.

[0063] S4: Collect the reacted copper electrode sheet into a new container and let it stand for 4 weeks until green two-dimensional nanosheet material grows on the surface of the foamed copper. This two-dimensional nanosheet material is Cu / Cu2O / Cu3(MoO4)2(OH)2 micro-nano material.

[0064] Example 5

[0065] This embodiment discloses a method for preparing metal / semiconductor / polyoxometalate heterostructure micro / nanomaterials, including the following steps:

[0066] S1: Place 99.999% pure copper foam on both sides of the reaction vessel, and place 99.999% pure molybdenum target in the center of the reaction vessel.

[0067] S2: Inject high-purity deionized water with a conductivity of 30 MΩ into the reaction vessel, ensuring that it covers the surface of the molybdenum target by 15 mm;

[0068] S3: 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 electric field induction (voltage 100V). Laser ablation parameters: wavelength 532nm, frequency 3Hz, energy 400mJ / pulse.

[0069] S4: Collect the reacted copper electrode sheet into a new container and let it stand for 5 weeks until green two-dimensional nanosheet material grows on the surface of the foamed copper. This two-dimensional nanosheet material is Cu / Cu2O / Cu3(MoO4)2(OH)2 micro-nano material.

[0070] Example 6

[0071] This embodiment discloses a method for preparing metal / semiconductor / polyoxometalate heterostructure micro / nanomaterials, including the following steps:

[0072] S1: Place 99.999% pure copper foam on both sides of the reaction vessel, and place 99.999% pure molybdenum target in the center of the reaction vessel.

[0073] S2: Inject high-purity deionized water with a conductivity of 30 MΩ into the reaction vessel, ensuring that it covers the surface of the molybdenum target by 15 mm;

[0074] S3: Turn on the laser and DC reaction power supply, and perform liquid phase laser ablation reaction on the molybdenum target for 2 hours under electric field induction (voltage 180V). Laser ablation parameters: wavelength 1064nm, frequency 8Hz, energy 850mJ / pulse.

[0075] S4: Collect the reacted copper electrode sheet into a new container and let it stand for 6 weeks until green two-dimensional nanosheet material grows on the surface of the foamed copper. This two-dimensional nanosheet material is Cu / Cu2O / Cu3(MoO4)2(OH)2 micro-nano material.

[0076] Application Example 1

[0077] Application of Cu / Cu2O / Cu3(MoO4)2(OH)2 heterojunction micro / nanomaterials prepared in Example 1 in electrocatalysts.

[0078] Electrochemical tests were performed on an electrochemical workstation using a traditional three-electrode system. The reference electrode was silver / silver chloride, the counter electrode was a platinum electrode, and the working electrode was a Cu / Cu₂O / Cu₃(MoO₄)₂(OH)₂ heterojunction micro / nanomaterial. A 1 mol / L sodium sulfate solution was used as the electrolyte. Linear sweep voltammetry (LSV) was employed, with a scan range of -0.6 V to 0.02 V and a scan rate of 10 mV / s. The LSV curves were recorded, and the results are shown below. Figure 3 As shown in the figure, the Cu / Cu2O / Cu3(MoO4)2(OH)2 heterostructure micro / nanomaterial exhibits performance at 10 mA / cm². 2 The hydrogen evolution overpotential is 110mV.

[0079] 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.

[0080] 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 metal / semiconductor / polyoxometalate heterostructure micro / nanomaterial, characterized in that, The chemical formula for the micro / nanomaterial is A / A x O / A y (BO z ) m (OH) n The micro / nanomaterial is a two-dimensional nanosheet structure, where A and B represent different metallic materials. x O represents a metal oxide, A y (BO z ) m (OH) n It represents a polyoxometalate, where x, y, z, m, and n are the corresponding elements or ions in quantity. A represents one of Fe, Co, Ni, Cu, and Zn materials, and B represents one of Mo, V, Nb, Ta, and W.

2. A method for preparing metal / semiconductor / polyoxometalate heterostructure micro / nanomaterials, characterized in that, Includes the following steps: Metal electrode A is placed on both sides of the reaction vessel, and metal target B is placed in the center of the reaction vessel. Deionized water is injected into the reaction vessel and submerges the surface of the metal B target. The metal B target was subjected to liquid-phase laser ablation reaction under the induction of an electric field; The reacted metal A electrode was collected in a new container and left to stand for at least two weeks until two-dimensional nanosheets grew on the surface of the metal A electrode. These two-dimensional nanosheets are the A / A material. x O / A y (BO z ) m (OH) n Micro and nano materials; Where A represents one of the materials Fe, Co, Ni, Cu, and Zn, and B represents one of the materials Mo, V, Nb, Ta, and W.

3. The method for preparing metal / semiconductor / polyoxometalate heterostructure micro / nanomaterials according to claim 2, characterized in that, The purity of the metal A electrode is 99%~99.999%, and the purity of the metal B target is 99%~99.999%.

4. The method for preparing metal / semiconductor / polyoxometalate heterostructure micro / nanomaterials according to claim 2, characterized in that, The deionized water covers the surface of the metal B target material by 2mm-15mm.

5. The method for preparing metal / semiconductor / polyoxometalate heterostructure micro / nanomaterials according to claim 2, characterized in that, The conductivity of the deionized water is 15 MΩ-30 MΩ.

6. The method for preparing metal / semiconductor / polyoxometalate heterostructure micro / nanomaterials according to claim 2, characterized in that, The parameters of the laser ablation are: wavelength of 355nm, 532nm or 1064nm, frequency of 1Hz to 10Hz, and energy of 50mJ to 850mJ / pulse.

7. The method for preparing metal / semiconductor / polyoxometalate heterostructure micro / nanomaterials according to claim 2, characterized in that, The reaction time is 30 min to 2 h.

8. The method for preparing metal / semiconductor / polyoxometalate heterostructure micro / nanomaterials according to claim 2, characterized in that, The voltage of the electric field is 5V-180V.

9. The method for preparing metal / semiconductor / polyoxometalate heterostructure micro / nanomaterials according to claim 2, characterized in that, The metal A electrode is a metal A electrode sheet or a foam metal.

10. The application of the metal / semiconductor / polyoxometalate heterojunction micro / nanomaterials according to claim 1 in electrocatalysts.

Images