Silver vanadate-based composite photoactive material and preparation method thereof
Patent Information
- Application Number
- CN202611005173.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-07
- Publication Date
- 2026-09-25
AI Technical Summary
[0005]为了解决现有物理复合的方法制备的Ag3VO4/红磷复合光活性材料存在Ag3VO4与红磷的界面结合力弱，导致光电流信号微弱、电荷传输效率低的技术问题，本发明提供一种钒酸银基复合光活性材料及其制备方法
1、本发明采用一步水热法制备钒酸银基复合光活性材料，通过控制反应温度（140℃～180℃）和红磷纳米片与钒酸银的质量比（0.8～1.2：1），使红磷纳米片表面的磷氧磷键与钒酸银表面的钒氧键发生原位脱水缩合，形成钒氧磷共价键，实现原子级界面耦合，构建以内建电场驱动的S型异质结。 该方法区别于现有物理混合、机械研磨或简单浸渍的制备方式，从根本上解决了界面仅依靠范德华力结合导致的结合力弱、易相分离、电荷传输势垒高的关键问题。通过该方法制备的复合材料界面结合牢固，在长期光照、湿度变化、酸碱环境及机械扰动下均不出现界面解离或组分脱落现象，结构完整性与界面稳定性显著优于同类红磷基复合材料。
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Abstract
Description
Technical Field
[0001] This invention relates to the field of photoelectric active materials technology, specifically to a silver vanadate-based composite photoactive material and its preparation method. Background Technology
[0002] Photoelectrochemical sensors, with their advantages of low background noise, high sensitivity, and low cost, show great promise in the detection of trace antibiotics. These sensors use photoactive materials as their core, generating detection signals through photoelectric conversion, and combining them with biometric elements to achieve specific detection of target analytes.
[0003] Existing photoactive materials for photoelectrochemical sensors are mainly divided into two categories: one is single semiconductor materials, such as red phosphorus (RP). Red phosphorus is an environmentally friendly, abundant, and narrow-bandgap (~1.78 eV) elemental semiconductor with broad-spectrum visible light absorption, good biocompatibility, and interfacial activity, making it highly promising for applications in the field of optoelectronic functional materials. However, pure red phosphorus has two major drawbacks in use: rapid recombination rate of photogenerated electron-hole pairs and low carrier separation efficiency; and poor conductivity, small specific surface area, and insufficient structural stability of the bulk material, which limits its application in high-performance optoelectronic devices.
[0004] Secondly, there are semiconductor materials with simple physical composites, such as Ag3VO4 / ZnO, red phosphorus / g-C3N4, and Ag3VO4 / red phosphorus composite photoactive materials. Among these, the preparation of Ag3VO4 / red phosphorus composite photoactive materials typically involves physical mixing, mechanical grinding, or simple impregnation. These physical composite methods only enable macroscopic physical contact between the two materials; the interface lacks atomic-level bonding, making it difficult to form an effective heterojunction structure with a built-in electric field. Essentially, they are physical composites rather than true semiconductor heterojunction materials. Because the interface relies solely on van der Waals forces for bonding, the contact resistance is high, the interface defect state density is large, and photogenerated carriers undergo severe random recombination at the interface, making directional separation and transport difficult. This results in weak photocurrent signals and low photoelectric conversion efficiency. Summary of the Invention
[0005] To address the technical problem of weak interfacial bonding between Ag3VO4 and red phosphorus in Ag3VO4 / red phosphorus composite photoactive materials prepared by existing physical composite methods, resulting in weak photocurrent signals and low charge transport efficiency, this invention provides a silver vanadate-based composite photoactive material and its preparation method.
[0006] This invention utilizes a one-step hydrothermal reaction to induce in-situ dehydration condensation between the phosphorus-oxygen-phosphorus bonds on the surface of red phosphorus nanosheets and the vanadium-oxygen bonds on the surface of silver vanadate, forming vanadium-oxygen-phosphorus covalent bonds. This achieves atomic-level interfacial coupling between the two semiconductor materials, constructing an S-type heterojunction driven by a built-in electric field. Simultaneously, ultrathin red phosphorus nanosheets are prepared using a liquid-phase ultrasonic exfoliation method. By controlling the mass ratio of red phosphorus nanosheets to silver vanadate, the hydrothermal reaction temperature, and time, a nanosheet composite structure with uniform particle size, large specific surface area, and high interfacial stability is obtained. The preparation method of this invention fundamentally overcomes the shortcomings of existing technologies where interfacial bonding relies solely on van der Waals forces, resulting in weak bonding, easy phase separation, and high charge transport barriers. It achieves directional separation and efficient transport of photogenerated carriers. Furthermore, the nanosheet structure shortens the carrier transport distance and increases active sites, thereby achieving comprehensive performance with low charge transfer resistance, strong photoelectric response, and excellent structural stability.
[0007] To achieve the above objectives, the technical solution of the present invention is as follows.
[0008] The first objective of this invention is to provide a method for preparing a silver vanadate-based composite photoactive material, comprising the following steps: Red phosphorus nanosheets and silver vanadate were dispersed in water to form a mixture. The mixture was subjected to a hydrothermal reaction at 140℃ to 160℃, which enabled the red phosphorus nanosheets and silver vanadate to form atomic-level interfacial coupling through VOP bonds, thereby constructing an S-shaped heterojunction driven by a built-in electric field and obtaining a silver vanadate-based composite photoactive material. The mass ratio of silver vanadate to red phosphorus nanosheets was 0.8 to 1.2:1.
[0009] Preferably, in the preparation process of the silver vanadate-based composite photoactive material, the hydrothermal reaction temperature is 150℃ and the time is 2h to 4h.
[0010] Preferably, the red phosphorus nanosheets are obtained by dispersing red phosphorus powder in water and carrying out a hydrothermal reaction at a temperature range of 190℃ to 210℃. The hydrothermal reaction product is then ultrasonically dispersed in N-methylpyrrolidone. After removing the precipitate by a first centrifugation, a second centrifugation is performed. The bottom precipitate is then washed and centrifuged a third time to obtain the red phosphorus nanosheets.
[0011] Preferably, the ultrasonic dispersion time is 30 minutes.
[0012] The second objective of this invention is to provide a silver vanadate-based composite photoactive material, wherein the silver vanadate-based composite photoactive material is constructed by coupling red phosphorus nanosheets and silver vanadate through VOP bonds to form an atomic-level interface, thereby constructing an S-shaped heterojunction driven by a built-in electric field.
[0013] Preferably, the silver vanadate-based composite photoactive material has an average particle size of 27 nm and a specific surface area of 15.29 m². 2 / g.
[0014] Preferably, the red phosphorus nanosheets have an average particle size of 393 nm and a specific surface area of 13.32 m². 2 / g.
[0015] Preferably, the silver vanadate has a bulk structure with an average particle size of 590 nm and a specific surface area of 0.91 m². 2 / g.
[0016] The beneficial effects of this invention are: 1. This invention employs a one-step hydrothermal method to prepare silver vanadate-based composite photoactive materials. By controlling the reaction temperature (140℃~180℃) and the mass ratio of red phosphorus nanosheets to silver vanadate (0.8~1.2:1), the phosphorus-oxygen-phosphorus bonds on the surface of the red phosphorus nanosheets undergo in-situ dehydration condensation with the vanadium-oxygen bonds on the surface of the silver vanadate, forming vanadium-oxygen-phosphorus covalent bonds. This achieves atomic-level interfacial coupling, constructing an S-shaped heterojunction driven by a built-in electric field. This method differs from existing preparation methods involving physical mixing, mechanical grinding, or simple impregnation, fundamentally solving the key problems of weak bonding, easy phase separation, and high charge transport barriers caused by relying solely on van der Waals forces for interfacial bonding. The composite material prepared by this method exhibits strong interfacial bonding and does not show interfacial dissociation or component detachment under long-term light exposure, humidity changes, acid and alkaline environments, or mechanical disturbances. Its structural integrity and interfacial stability are significantly superior to similar red phosphorus-based composite materials.
[0017] 2. The silver vanadate-based composite photoactive material prepared in this invention utilizes the band structure matched with Ag3VO4 and red phosphorus nanosheets, along with the built-in electric field, to construct a typical S-type heterojunction charge transfer path through covalent bonds at the vanadium-oxygen-phosphorus interface, achieving efficient directional separation of photogenerated carriers. This structure can selectively recombine low-energy electron-hole pairs while retaining high-energy carriers with strong redox capabilities, significantly suppressing random carrier recombination. The charge transfer resistance of this material is reduced to 112 Ω, only 1 / 15 that of pure Ag3VO4 and 1 / 3 that of pure red phosphorus nanosheets; the average particle size is only 27 nm, much smaller than that of bulk red phosphorus nanosheets (393 nm) and bulk Ag3VO4 (590 nm), forming an ultrathin nanosheet composite structure, which significantly shortens the carrier transport distance from the bulk phase to the surface and reduces bulk recombination losses.
[0018] 3. The specific surface area of the silver vanadate-based composite photoactive material prepared by this invention reaches 15.29 m². 2The material exhibits a vanadium-oxygen-phosphorus interfacial density (VOCs) that is 14.8% higher than that of pure red phosphorus nanosheets and 16.8 times higher than that of pure Ag3VO4, exposing a large number of highly active interfacial sites, significantly enhancing interfacial reactivity, charge adsorption capacity, and photoelectric conversion efficiency. The light absorption tail extends to 743 nm, significantly broadening the visible light absorption range and greatly improving the utilization of sunlight. The vanadium-oxygen-phosphorus interfacial covalent bonds can serve as photogenerated carrier trapping centers, further enhancing light absorption and photoelectric conversion efficiency, enabling the material to maintain excellent photoelectric response characteristics under weak and visible light conditions. This material is a purely inorganic optoelectronic functional substrate, without biological modification or specific catalytic targeting, and can be directly applied to multiple high-tech fields such as photodetectors, photoconversion devices, photoelectrochemical electrodes, functional sensing substrates, environmental optoelectronic materials, and flexible optoelectronic devices. Attached Figure Description
[0019] Figure 1 This is the FT-IR image of the Ag3VO4 / HRP NSs S-type heterojunction.
[0020] Figure 2 These are electrochemical test results for the Ag3VO4 / HRP NSs S-type heterojunction. A is the photocurrent test result; B is the electrochemical impedance spectroscopy (EIS) diagram.
[0021] Figure 3 This is a BET plot of the Ag3VO4 / HRP NSs S-type heterojunction. A represents the nitrogen adsorption-desorption isotherms of HRP NSs, Ag3VO4, and Ag3VO4 / HRP NSs; B represents the pore size distribution curve.
[0022] Figure 4 This is a particle size distribution diagram of Ag3VO4 / HRP NSs S-type heterojunctions. Detailed Implementation
[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.
[0024] To address the technical bottlenecks of weak interfacial bonding and low charge transport efficiency in existing Ag3VO4 / red phosphorus composite materials, this invention proposes a silver vanadate-based composite photoactive material and its preparation method based on the synergistic optimization of atomic-level interfacial bonding and nanosheet structure. The preparation of this silver vanadate-based composite photoactive material involves a hydrothermal reaction that dehydrates and condenses the phosphorus-oxygen-phosphorus bonds on the surface of red phosphorus nanosheets with the vanadium-oxygen bonds on the surface of silver vanadate, forming vanadium-oxygen-phosphorus covalent bonds. This constructs an S-shaped heterojunction driven by a built-in electric field, achieving directional separation and efficient transport of photogenerated carriers. Simultaneously, the ultrathin nanosheet structure shortens the carrier transport distance, increases the specific surface area, and exposes highly active interfacial sites, resulting in comprehensive performance characteristics such as low charge transfer resistance, strong photoelectric response, wide light absorption range, and excellent structural stability. This material can be widely applied in the fields of photoelectric detection, photoelectric conversion, and photoelectrochemical functional materials.
[0025] The technical solution of the present invention will be further described below through specific embodiments. Unless otherwise specified, the methods described in the following embodiments are conventional methods; the reagents and materials described are commercially available unless otherwise specified.
[0026] Example 1 A method for preparing a silver vanadate-based composite photoactive material includes the following steps: S1. Weigh 0.6g of commercial red phosphorus (RP) powder, add 20mL of deionized water and stir to form a uniform suspension. Transfer to a hydrothermal reactor and react at 200℃ for 12h. After natural cooling, hydrothermal red phosphorus nanosheets (HRP) are obtained. Disperse 0.6g of HRP in 60mL of N-methylpyrrolidone (NMP), sonicate with a probe for 5h, centrifuge at 7000rpm for 20min to discard the bulk precipitate, centrifuge the supernatant at 15000rpm for 20min to collect the product, wash three times alternately with deionized water and ethanol, and vacuum dry at 60℃ for 12h to obtain HRP NSs.
[0027] S2. Dissolve 0.03 mol NaOH and 0.005 mol V₂O₅ in 20 mL of deionized water and stir at room temperature for 30 min until transparent; this solution is denoted as solution A. Dissolve 0.03 mol AgNO₃ in 20 mL of deionized water; this solution is denoted as solution B. Add solution B dropwise to solution A under magnetic stirring, and continue stirring for 3 h to form a yellow precipitate. Transfer the precipitate to a hydrothermal reactor and react at 160 °C for 4 h. After cooling, wash with deionized water / ethanol and freeze-dry for 24 h to obtain pure phase Ag₃VO₄ powder.
[0028] S3. Weigh HRP NSs and Ag3VO4 powder at a mass ratio of 0.8:1, add 30 mL of deionized water, and sonicate for 30 min to form a homogeneous mixture. Transfer the mixture to a hydrothermal reactor and react at 150℃ for 4 h. A stable S-type heterojunction is constructed by forming VOP interfacial covalent bonds through in-situ dehydration condensation. After the reaction, allow it to cool naturally to room temperature, collect the product by filtration, wash three times with deionized water, and vacuum dry at 60℃ for 6 h to obtain the silver vanadate-based composite photoactive material, denoted as Ag3VO4 / HRP NSs.
[0029] The silver vanadate-based composite photoactive material prepared in Example 1 of this invention exhibits the highest content of interfacial VOP covalent bonds, a complete S-type heterojunction structure, uniform particle size (27 nm), and the largest specific surface area (15.29 nm). 2 It has the lowest charge transfer resistance (112Ω) and the best photoelectric performance and stability.
[0030] Example 2 A method for preparing a silver vanadate-based composite photoactive material includes the following steps: S1. Weigh 0.6g of commercial RP powder, add 20mL of deionized water and stir to form a uniform suspension. Transfer to a hydrothermal reactor and react at 200℃ for 12h. Allow to cool naturally to obtain hydrothermal HRP. Disperse 0.6g of HRP in 60mL of N-methylpyrrolidone (NMP), sonicate with a probe for 5h, centrifuge at 7000rpm for 20min to discard the bulk precipitate, centrifuge the supernatant at 15000rpm for 20min to collect the product, wash three times alternately with deionized water and ethanol, and vacuum dry at 60℃ for 12h to obtain HRP NSs.
[0031] S2. Dissolve 0.03 mol NaOH and 0.005 mol V₂O₅ in 20 mL of deionized water and stir at room temperature for 30 min until transparent; this solution is denoted as solution A. Dissolve 0.03 mol AgNO₃ in 20 mL of deionized water; this solution is denoted as solution B. Add solution B dropwise to solution A under magnetic stirring, and continue stirring for 3 h to form a yellow precipitate. Transfer the precipitate to a hydrothermal reactor and react at 160 °C for 4 h. After cooling, wash with deionized water / ethanol and freeze-dry for 24 h to obtain pure phase Ag₃VO₄ powder.
[0032] S3. Weigh HRP NSs and Ag3VO4 powder at a mass ratio of 1.2:1, add 30 mL of deionized water, and sonicate for 30 min to form a homogeneous mixture. Transfer the mixture to a hydrothermal reactor and react at 150℃ for 4 h. A stable S-shaped heterojunction is constructed by in-situ dehydration condensation to form VOP interfacial covalent bonds. After the reaction, allow it to cool naturally to room temperature, collect the product by filtration, wash three times with deionized water, and vacuum dry at 60℃ for 6 h to obtain the silver vanadate-based composite photoactive material, denoted as Ag3VO4 / HRP NSs.
[0033] The silver vanadate-based composite photoactive material prepared in Example 2 of this invention exhibits slight agglomeration, and its specific surface area and carrier separation efficiency decrease slightly.
[0034] Example 3 A method for preparing a silver vanadate-based composite photoactive material includes the following steps: S1. Weigh 0.6g of commercial RP powder, add 20mL of deionized water and stir to form a uniform suspension. Transfer to a hydrothermal reactor and react at 200℃ for 12h. Allow to cool naturally to obtain hydrothermal HRP. Disperse 0.6g of HRP in 60mL of N-methylpyrrolidone (NMP), sonicate with a probe for 5h, centrifuge at 7000rpm for 20min to discard the bulk precipitate, centrifuge the supernatant at 15000rpm for 20min to collect the product, wash three times alternately with deionized water and ethanol, and vacuum dry at 60℃ for 12h to obtain HRP NSs.
[0035] S2. Dissolve 0.03 mol NaOH and 0.005 mol V₂O₅ in 20 mL of deionized water and stir at room temperature for 30 min until transparent; this solution is denoted as solution A. Dissolve 0.03 mol AgNO₃ in 20 mL of deionized water; this solution is denoted as solution B. Add solution B dropwise to solution A under magnetic stirring, and continue stirring for 3 h to form a yellow precipitate. Transfer the precipitate to a hydrothermal reactor and react at 160 °C for 4 h. After cooling, wash with deionized water / ethanol and freeze-dry for 24 h to obtain pure phase Ag₃VO₄ powder.
[0036] S3. Weigh HRP NSs and Ag3VO4 powder at a mass ratio of 0.8:1, add 30 mL of deionized water, and sonicate for 30 min to form a homogeneous mixture. Transfer the mixture to a hydrothermal reactor and react at 150℃ for 2 h. A stable S-shaped heterojunction is constructed by in-situ dehydration condensation to form VOP interfacial covalent bonds. After the reaction, allow it to cool naturally to room temperature, collect the product by filtration, wash three times with deionized water, and vacuum dry at 60℃ for 6 h to obtain the silver vanadate-based composite photoactive material, denoted as Ag3VO4 / HRP NSs.
[0037] The silver vanadate-based composite photoactive material prepared in Example 3 of this invention has insufficient hydrothermal reaction time, resulting in inadequate interfacial bonding and reduced heterojunction stability.
[0038] Example 4 A method for preparing a silver vanadate-based composite photoactive material includes the following steps: S1. Weigh 0.6g of commercial RP powder, add 20mL of deionized water and stir to form a uniform suspension. Transfer to a hydrothermal reactor and react at 200℃ for 12h. Allow to cool naturally to obtain hydrothermal HRP. Disperse 0.6g of HRP in 60mL of N-methylpyrrolidone (NMP), sonicate with a probe for 5h, centrifuge at 7000rpm for 20min to discard the bulk precipitate, centrifuge the supernatant at 15000rpm for 20min to collect the product, wash three times alternately with deionized water and ethanol, and vacuum dry at 60℃ for 12h to obtain HRP NSs.
[0039] S2. Dissolve 0.03 mol NaOH and 0.005 mol V₂O₅ in 20 mL of deionized water and stir at room temperature for 30 min until transparent; this solution is denoted as solution A. Dissolve 0.03 mol AgNO₃ in 20 mL of deionized water; this solution is denoted as solution B. Add solution B dropwise to solution A under magnetic stirring, and continue stirring for 3 h to form a yellow precipitate. Transfer the precipitate to a hydrothermal reactor and react at 160 °C for 4 h. After cooling, wash with deionized water / ethanol and freeze-dry for 24 h to obtain pure phase Ag₃VO₄ powder.
[0040] S3. Weigh HRP NSs and Ag3VO4 powder at a mass ratio of 0.8:1, add 30 mL of deionized water, and sonicate for 30 min to form a homogeneous mixture. Transfer the mixture to a hydrothermal reactor and react at 180℃ for 4 h. A stable S-type heterojunction is constructed by forming VOP interfacial covalent bonds through in-situ dehydration condensation. After the reaction, allow it to cool naturally to room temperature, collect the product by filtration, wash three times with deionized water, and vacuum dry at 60℃ for 6 h to obtain the silver vanadate-based composite photoactive material, denoted as Ag3VO4 / HRP NSs.
[0041] The photoelectric response of the silver vanadate-based composite photoactive material prepared in Example 4 of this invention was slightly weakened due to excessive grain growth caused by the high hydrothermal temperature.
[0042] Comparative Example 1 A method for preparing HRP NSs photoactive materials includes the following steps: Weigh 0.6 g of commercial RP powder, add 20 mL of deionized water and stir to form a uniform suspension. Transfer the suspension to a hydrothermal reactor and react at 200 °C for 12 h. After natural cooling, hydrothermal HRP is obtained. Disperse 0.6 g of HRP in 60 mL of N-methylpyrrolidone (NMP), sonicate with a probe for 5 h, centrifuge at 7000 rpm for 20 min to discard the bulk precipitate, centrifuge the supernatant at 15000 rpm for 20 min to collect the product, wash three times with alternating deionized water and ethanol, and vacuum dry at 60 °C for 12 h to obtain HRP NSs photoactive material.
[0043] Comparative Example 2 A method for preparing Ag3VO4 powder photoactive material includes the following steps: 0.03 mol NaOH and 0.005 mol V₂O₅ were dissolved in 20 mL of deionized water and stirred at room temperature for 30 min until transparent; this solution is denoted as solution A. 0.03 mol AgNO₃ was dissolved in 20 mL of deionized water; this solution is denoted as solution B. Solution B was added dropwise to solution A under magnetic stirring, and stirring continued for 3 h to form a yellow precipitate. This precipitate was transferred to a hydrothermal reactor and reacted at 160 °C for 4 h. After cooling, the precipitate was washed with deionized water / ethanol and freeze-dried for 24 h to obtain pure-phase Ag₃VO₄ powder photoactive material.
[0044] Infrared spectroscopy was performed on the photoactive materials prepared in Example 1, Comparative Example 1, and Comparative Example 2. The results are as follows: Figure 1 As shown. Figure 1 This indicates that the photoactive material prepared in Example 1 has a thickness of 950 cm. -1 The presence of VOP characteristic absorption peaks nearby confirms the existence of stable VOP covalent bonds at the Ag3VO4 and HRP NSs interface, achieving atomic-level interface coupling and fundamentally solving the defects of weak bonding and easy phase separation in traditional physical composite interfaces.
[0045] The photoelectrochemical properties of the photoactive materials prepared in Example 1, Comparative Example 1, and Comparative Example 2 were tested, and the results are as follows: Figure 2 As shown.
[0046] Figure 2 Figure A shows the photocurrent test results. The test conditions were as follows: fluorine-doped tin oxide electrodes modified with photoactive materials prepared in Examples 1, 1, and 2 were used as the working electrodes; platinum wire was used as the counter electrode; a saturated silver chloride electrode was used as the reference electrode; the electrolyte was 0.1 mol / L phosphate buffer; the light source was a 300W xenon lamp; and a bias voltage of 0.7V was applied. The results showed that the photocurrent response intensity of the photoactive material prepared in Example 1 was significantly higher than that of hydrothermally treated red phosphorus nanosheets and pure Ag3VO4, indicating a significant improvement in photogenerated carrier separation efficiency.
[0047] Figure 2 Figure B shows the electrochemical impedance spectroscopy (Nyquist plot). The testing conditions were: containing 5 mmol / L redox probe [Fe(CN)6]. 3- / 4- A 0.1 mol / L phosphate buffer solution was used, with the DC potential set to open circuit potential. A sinusoidal AC perturbation signal with an amplitude of 5 mV was applied, and the scanning frequency range was 100 kHz to 0.01 Hz. The results showed that the charge transfer resistance of the composite material was reduced to 112 Ω, which is only 1 / 15 of that of pure Ag3VO4 and 1 / 3 of that of pure hydrothermally treated red phosphorus nanosheets. This confirms that the construction of the S-type heterojunction effectively reduced the interfacial charge transport barrier and achieved efficient directional carrier transport.
[0048] The nitrogen adsorption-desorption isotherm was determined using the Bruno-Emmett-Taylor method, and the pore size distribution was calculated using the Barrett-Joyner-Halenda method. Figure 3 In Figure A, the nitrogen adsorption-desorption isotherm is shown. The isotherms of Ag3VO4, hydrothermally treated red phosphorus nanosheets, and Ag3VO4 / HRP NSs are all type IV, accompanied by an H3-type hysteresis loop, indicating the presence of a mesoporous structure in the materials. In the high-pressure range, the nitrogen adsorption capacity of the composite material is significantly increased, and slightly higher than that of pure hydrothermally treated red phosphorus nanosheets. Figure 3 B is the pore size distribution curve. After composite formation, the pore size distribution is concentrated, exposing a large number of highly active interface sites.
[0049] Calculations show that the specific surface area of the photoactive material prepared in Example 1 reaches 15.29 m². 2 / g, significantly higher than that of pure hydrothermal treated red phosphorus nanosheets (13.32m). 2 / g) and pure Ag3VO4 (0.91m 2 / g), which are 1.15 times and 16.8 times that of the latter, respectively.
[0050] The microstructure of the photoactive materials prepared in Example 1, Comparative Example 1, and Comparative Example 2 was tested, and the results are as follows: Figure 4 As shown.
[0051] The composite material prepared by this invention exhibits an ultrathin nanosheet composite structure with an average particle size of only 27 nm, which is much smaller than the 393 nm of pure hydrothermally treated red phosphorus nanosheets and the 590 nm of pure Ag3VO4. The nanosheet morphology significantly shortens the transport distance of charge carriers from the bulk phase to the surface, thereby reducing bulk recombination losses.
[0052] The above results demonstrate that by adjusting parameters such as the ratio, temperature, and time, the embodiments of the present invention can stably obtain Ag3VO4 / HRP S-type heterojunction materials with controllable structure and performance, proving that the method of the present invention has good repeatability, controllability, and practicality.
[0053] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing a silver vanadate-based composite photoactive material, characterized in that, Includes the following steps: Red phosphorus nanosheets and silver vanadate were dispersed in water to form a mixture. The mixture was subjected to a hydrothermal reaction at 140℃~180℃, so that the red phosphorus nanosheets and silver vanadate formed an atomic-level interface coupling through VOP bonds, and an S-shaped heterojunction driven by a built-in electric field was constructed to obtain a silver vanadate-based composite photoactive material. The mass ratio of silver vanadate to red phosphorus nanosheets is 0.8–1.2:
1.
2. The method for preparing the silver vanadate-based composite photoactive material according to claim 1, characterized in that, In the preparation of silver vanadate-based composite photoactive materials, the hydrothermal reaction temperature is 150℃ and the time is 2h to 4h.
3. The method for preparing the silver vanadate-based composite photoactive material according to claim 1, characterized in that, The red phosphorus nanosheets are obtained by dispersing red phosphorus powder in water and carrying out a hydrothermal reaction at 190℃~210℃. The hydrothermal reaction product is ultrasonically dispersed in N-methylpyrrolidone. After removing the precipitate by the first centrifugation, the product is centrifuged a second time, and the bottom precipitate is washed and centrifuged a third time to obtain the red phosphorus nanosheets.
4. The method for preparing the silver vanadate-based composite photoactive material according to claim 1, characterized in that, The ultrasonic dispersion time was 30 minutes.
5. A silver vanadate-based composite photoactive material, characterized in that, The silver vanadate-based composite photoactive material was prepared using any one of claims 1 to 4. The silver vanadate-based composite photoactive material is constructed by coupling red phosphorus nanosheets and silver vanadate through VOP bonds to form an atomic-level interface, thereby creating an S-shaped heterojunction driven by a built-in electric field.
6. The silver vanadate-based composite photoactive material according to claim 5, characterized in that, The silver vanadate-based composite photoactive material has an average particle size of 27 nm and a specific surface area of 15.29 m². 2 / g.
7. The silver vanadate-based composite photoactive material according to claim 5, characterized in that, The red phosphorus nanosheets have an average particle size of 393 nm and a specific surface area of 13.32 m². 2 / g.
8. The silver vanadate-based composite photoactive material according to claim 5, characterized in that, The silver vanadate has a bulk structure with an average particle size of 590 nm and a specific surface area of 0.91 m². 2 / g.