Preparation method of controllable multi-morphology photoelectric composite material and photoelectric anode thereof

Abstract

The invention discloses a preparation method of a controllable multi-morphology photoelectric composite material, which comprises the following steps: preparing a metal-doped needle-shaped precursor by taking a conductive metal material as a substrate, then taking the precursor as a carrier, and directionally inducing BiOBr to grow on the carrier in situ by regulating hydrothermal reaction conditions and a reaction solvent to form different morphologies, thereby obtaining the controllable multi-morphology photoelectric composite material. The reaction solvent is 2-methoxyethanol or a mixture of 2-methoxyethanol, an active medium, a regulating agent and a surfactant; by optimizing the solvent type (such as a mixed solvent of 2-methoxyethanol and ethylene glycol, a mixed solvent of water and 2-methoxyethanol or a polar solvent containing a trace regulator) of a reaction system and combining hydrothermal reaction conditions, BiOBr can be directionally induced to grow into a hydrangea flower shape, a celery flower shape, a cockscomb flower shape and other specific morphologies; and through the synergistic effect of different solvent systems and the precursor microenvironment, the bonding strength and dispersion uniformity of BiOBr and the carrier can be further enhanced, and the formed product is uniform in morphology, high in crystallinity and high in performance stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of inorganic nano-photocatalytic fuel cells, and particularly relates to a synthesis method for growing in-situ specified morphology BiOBr photoelectric composite materials on needle-like precursors by changing reaction conditions and reaction solvents. BACKGROUND

[0002] As an important V-VI-VII ternary semiconductor photocatalytic material, bismuth oxyhalide (BiOX) has attracted extensive attention due to its unique layered structure and suitable optical band gap. Among them, BiOBr has good chemical stability and visible light response ability, and shows good application prospect in photocatalytic degradation of organic pollutants. However, the traditional BiOBr powder catalyst has problems such as easy agglomeration and difficult recovery, which limits its practical application. Anchoring the photocatalytic active component on a suitable carrier is a key link to realize efficient and sustainable photocatalytic technology. The most commonly used photocatalyst carrier is nickel foam, which is a three-dimensional porous material with high specific surface area and good electrical conductivity, and is an ideal photocatalyst carrier. However, directly loading BiOBr on the photocatalyst carrier often has problems such as weak binding force and uneven distribution. In addition, the existing technology generally has technical defects such as uneven product morphology, low crystallinity and insufficient performance stability, and the core problem lies in the poor adaptability of the solvent system and the insufficient precision of the reaction condition regulation. Traditional hydrothermal synthesis usually uses single deionized water or simple alcohol as the solvent. Such solvents have single polarity and weak coordination ability, and are difficult to effectively regulate the nucleation and growth process of the product, resulting in problems such as easy agglomeration and uncontrollable morphology of the product.

[0003] Therefore, it is necessary to solve the problems of weak binding force and uneven distribution of BiOBr loaded on the photocatalyst carrier, as well as the problems of uneven product morphology, low crystallinity and insufficient performance stability of the formed product. SUMMARY

[0004] Therefore, the purpose of the present application is to provide a preparation method of photoelectric composite material with controllable multi-morphology and a photoelectric anode, which can not only solve the problems of weak binding force and uneven distribution of BiOBr loaded on the photocatalyst carrier, as well as the problems of uneven product morphology, low crystallinity and insufficient performance stability of the formed product, but also realize the controllability of the nucleation and growth process of the target product, and in-situ growth of different specific morphologies.

[0005] The preparation method of the photoelectric composite material with controllable polymorphology of the application comprises the following steps: preparing a metal-doped needle-shaped precursor with a conductive metal material as a substrate, then directing in-situ growth of BiOBr on the carrier by adjusting the hydrothermal reaction conditions and reaction solvents to form different morphologies, and the reaction solvent is 2-methoxyethanol or a mixture of 2-methoxyethanol and active medium, regulating agent and surfactant.

[0006] Further, the active medium is ethylene glycol, the regulating agent is Polyvinylpyrrolidone , and the surfactant is cetyltrimethylammonium bromide.

[0007] Further, in the photoelectric composite material, the sheet thickness of BiOBr is 50-100 nm, and the assembly diameter is 1-3 μm.

[0008] Further, it specifically comprises the following steps:

[0009] S1, preparing a metal-doped needle-shaped precursor with a conductive metal material as a substrate;

[0010] S2-1, preparing a ball-shaped photoelectric composite material: dissolving Bi(NO3)3·5H2O and KBr in a mixed solution of 2-methoxyethanol and active medium, stirring uniformly, and performing hydrothermal reaction on the obtained solution and the dried needle-shaped precursor;

[0011] S2-2, preparing a thistle flower-shaped photoelectric composite material: dissolving Bi(NO3)3·5H2O in a mixed solution of regulating agent and ethylene glycol, adding surfactant and stirring uniformly, and performing hydrothermal reaction on the obtained solution and the dried needle-shaped precursor;

[0012] S2-3, preparing a cockcomb flower-shaped photoelectric composite material: dissolving Bi(NO3)3·5H2O and surfactant in a 2-methoxyethanol aqueous solution, stirring uniformly, and performing hydrothermal reaction on the obtained solution and the dried needle-shaped precursor;

[0013] Further, in step S2-1, the mass ratio of Bi(NO3)3·5H2O to KBr is 3.5-4.5:1, and the mass ratio of 2-methoxyethanol to active medium is 1:1.

[0014] Further, in step S2-2, the mass ratio of Bi(NO3)3·5H2O to surfactant is 0.8-1:1, and the mass ratio of Bi(NO3)3·5H2O to regulating agent is 90-106:1.

[0015] Further, in step S2-3, the mass ratio of Bi(NO3)3·5H2O to surfactant is 3.5-4.5:1.

[0016] Further, the temperature of the hydrothermal reaction is 100-180 DEG C, and the hydrothermal reaction time is 5-15 hours, and by controlling the temperature and reaction time of the hydrothermal reaction, the morphology of the photoelectric composite material can be controlled.

[0017] Further, in step S1, the foam nickel is used as a substrate and doped with Fe, Ag and Ti metals to prepare the foam nickel-based needle-shaped photoelectric composite material.

[0018] The application further discloses a BiOBr-based photoelectric anode prepared by the preparation method.

[0019] The application has the following beneficial effects: the preparation method of the photoelectric composite material with controllable morphology and the photoelectric anode thereof can directively induce BiOBr to grow into specific morphologies such as ball-shaped, thistle flower-shaped and cockscomb flower-shaped by optimizing the solvent type of the reaction system (such as 2-methoxyethanol and glycol mixed solvents, water and 2-methoxyethanol mixed solvents or polar solvents containing trace amount of adjusting agents) and combining with the hydrothermal reaction condition, and the synergistic effect of different solvent systems and the micro-environment of the precursor can further strengthen the binding strength and dispersion uniformity of BiOBr and the carrier, and the formed product has uniform morphology, high crystallinity and high performance stability. BRIEF DESCRIPTION OF DRAWINGS

[0020] The application will be further described below in combination with the drawings and examples:

[0021] Figure 1 X-ray diffraction (XRD) spectra of the prepared BiOBr@FAT-NF photoelectric anode samples are shown in the figure, wherein the curves BiOBr@FAT-NF-1, BiOBr@FAT-NF-2 and BiOBr@FAT-NF-3 correspond to the XRD spectra of the samples of example 1, example 2 and example 3 respectively.

[0022] Figure 2 SEM pictures of the prepared BiOBr@FAT-NF photoelectric anode samples are shown in the figure, wherein BiOBr@FAT-NF-1, BiOBr@FAT-NF-2 and BiOBr@FAT-NF-3 correspond to the SEM pictures of the samples of example 1, example 2 and example 3 respectively.

[0023] Figure 3 Electrochemical test results of the prepared BiOBr@FAT-NF photoelectric anode samples are shown in the figure, wherein BiOBr@FAT-NF-1, BiOBr@FAT-NF-2 and BiOBr@FAT-NF-3 correspond to the LSV and EIS pictures of the samples of example 1, example 2 and example 3 respectively. DETAILED DESCRIPTION

[0024] The preparation method of the photoelectric composite material with controllable polymorphology in the embodiment comprises the following steps: preparing a metal-doped needle-shaped precursor with a conductive metal material as a substrate, then directing in-situ growth of BiOBr on the carrier by adjusting and controlling the hydrothermal reaction conditions and reaction solvents to form different morphologies, and the reaction solvent is 2-methoxyethanol or a mixture of 2-methoxyethanol and active medium, control agent and surfactant; the conductive metal material for preparing the conductive metal material of the photoanode can be selected from multiple types such as noble metals, high work function metals, conventional metals, transparent conductive oxides, carbon-based materials and conductive polymers. When actually selecting the material, factors such as work function matching, chemical / thermal stability, optical transmission, cost and interface engineering should be considered comprehensively to realize an efficient and durable photoanode. Metal doping is a key means to improve the light absorption, carrier separation and electrocatalytic activity of the photoanode. Through various preparation technologies such as hydrothermal, pulsed laser liquid phase, single-source precursor, ALD / sputtering, precise doping can be realized for different substrates. The doped metal is a photoelectric active metal, which refers to a metal or metal-based material that can generate electron-hole pairs, realize photoelectric charge separation and participate in photoelectric conversion (such as photocatalysis, photovoltaic cells, photoelectric sensors, etc.) under light. They often realize efficient light absorption and charge transport through the electronic structure of the metal center, energy band matching or metal-ligand / metal-oxygen / metal-nitrogen interaction. Photoelectric active metals cover traditional metal complexes, metal oxides, metal sulfides / nitrides, to emerging metal-organic frameworks and liquid metal composite systems. In the embodiment, a foam nickel substrate is preferably used, and Fe, Ag and Ti doping is performed to prepare the precursor.

[0025] In the embodiment, the active medium is ethylene glycol, the control agent is Polyvinylpyrrolidone , and the surfactant is cetyltrimethylammonium bromide; 2-methoxyethanol is used as a basic solvent, 2-methoxyethanol can be mixed with pure water as a mixed solvent, 2-methoxyethanol can also be used with an active medium (such as ethylene glycol), or a control agent (such as Polyvinyl Pyrrolidone ) can also be used, the content of the control agent should be trace, or 2-methoxyethanol can be used with a surfactant (such as cetyltrimethylammonium bromide) according to actual conditions, or 2-methoxyethanol can be used with an active medium, a control agent and a surfactant. Through the trinity of “basic solvent-active medium-control agent” hydrothermal solvent formula, combined with different hydrothermal reaction conditions, the specific morphology BiOBr@FAT-NF composite material prepared has excellent crystallinity and stable photoelectrochemical performance.

[0026] In the embodiment, the steps specifically include:

[0027] S1. A metal-doped needle-like precursor is prepared using a conductive metal material as a substrate. Nickel foam is used as the substrate, and the nickel foam substrate is treated as follows: first, the nickel foam is cut into appropriately sized blocks, then ultrasonically treated with HCl for 10 min, followed by ultrasonic treatment with anhydrous ethanol for 30 min, and finally ultrasonic treatment with deionized water for 30 min, followed by drying to obtain the treated nickel foam substrate. The nickel foam is 3cm × 3cm in size, the acetone soaking time is 15-25 minutes, the hydrochloric acid concentration is 8-12mM, the ultrasonic treatment time is 15-25 minutes, and the drying temperature is 50-70℃.

[0028] Preparation of the needle-like precursor (FAT-NF): Anhydrous ethanol and a titanium source were mixed and sonicated to obtain solution A. Anhydrous ethanol, a silver source, an iron source, and a surfactant were mixed and sonicated to adjust the pH to obtain solution B. Solution B was then slowly added dropwise to solution A and stirred until the mixture reached a sol state. A nickel foam substrate was then immersed in the sol for a certain period of time, removed, and dried at a certain temperature. This process was repeated multiple times to obtain the needle-like precursor (FAT-NF). The titanium source was titanium isopropyl ester, with a dosage of 2.7-2.8 mL; the silver source was AgNO3, with a dosage of 1.7-1.8 mL; the iron source was Fe(NO3)3·9H2O, with a dosage of 0.16 g; and the surfactant was CTAB, with a dosage of 0.09-0.10 g.

[0029] The concentration of the EDTA-Na solution is 0.07-0.08 mol / L, the volume is 70-80 mL, the pH is adjusted to 2-4, the number of repetitions is 6-8, and the immersion time for each time is 3-5 minutes.

[0030] Then, photoelectric composite materials with different morphologies were prepared according to different reaction conditions:

[0031] One embodiment involves preparing a hydrangea-shaped optoelectronic composite material: Bi(NO3)3·5H2O and KBr are dissolved in a mixed solution of 2-methoxyethanol and an active medium and stirred until homogeneous. The resulting solution is then subjected to a hydrothermal reaction with a dried needle-shaped precursor. The mass ratio of Bi(NO3)3·5H2O to KBr is 3.5-4.5:1, and the mass ratio of 2-methoxyethanol to the active medium is 1:1.

[0032] One embodiment involves preparing an erythropoiesis flower-shaped photoelectric composite material: Bi(NO3)3·5H2O is dissolved in a mixed solution of a regulator and ethylene glycol, a surfactant is added and stirred until homogeneous, and the resulting solution is subjected to a hydrothermal reaction with a dried needle-shaped precursor; the mass ratio of Bi(NO3)3·5H2O to surfactant is 0.8-1:1; the mass ratio of Bi(NO3)3·5H2O to regulator is 90-106:1.

[0033] One example is the preparation of a cockscomb-shaped optoelectronic composite material: Bi(NO3)3·5H2O and a surfactant are dissolved in an aqueous solution of 2-methoxyethanol and stirred until homogeneous. The resulting solution is then subjected to a hydrothermal reaction with a dried needle-like precursor. The mass ratio of Bi(NO3)3·5H2O to the surfactant is 3.5-4.5:1.

[0034] In the above embodiments, the hydrothermal reaction temperature is 100-180℃ and the hydrothermal reaction time is 5-15 hours. The morphology of the optoelectronic composite material can be controlled by controlling the hydrothermal reaction temperature and reaction time.

[0035] This embodiment also discloses a BiOBr-based photoanode, which is prepared by the above preparation method. The BiOBr sheet thickness is 50-100 nm and the assembly diameter is 1-3 μm.

[0036] Example 1

[0037] Preparation of metal-doped needle-like precursors using nickel foam as a substrate:

[0038] Treatment of the nickel foam substrate: First, the nickel foam was cut into appropriately sized blocks. Then, it was ultrasonically treated with HCl for 10 min, followed by ultrasonic treatment with anhydrous ethanol for 30 min, and finally ultrasonic treatment with deionized water for 30 min. The treated nickel foam substrate was then dried. The nickel foam was 3cm × 3cm in size. The acetone soaking time was 20 minutes, the hydrochloric acid concentration was 10mM, the ultrasonic treatment time was 20 minutes, and the drying temperature was 60℃.

[0039] Preparation of the needle-like precursor (FAT-NF): Anhydrous ethanol and a titanium source were mixed and sonicated to obtain solution A. Anhydrous ethanol, a silver source, an iron source, and a surfactant were mixed and sonicated to adjust the pH to obtain solution B. Solution B was then slowly added dropwise to solution A and stirred until the mixture reached a sol state. A nickel foam substrate was then immersed in the sol for a certain period of time, removed, and dried at a certain temperature. This process was repeated multiple times to obtain the needle-like precursor (FAT-NF). The titanium source was titanium isopropyl ester, with a dosage of 2.8 mL; the silver source was AgNO3, with a dosage of 1.8 mL; the iron source was Fe(NO3)3·9H2O, with a dosage of 0.16 g; and the surfactant was CTAB, with a dosage of 0.10 g.

[0040] The concentration of the EDTA-Na solution was 0.08 mol / L, the volume was 80 mL, the pH was adjusted to 3, the process was repeated 7 times, and the immersion time was 4 minutes each time.

[0041] Preparation of hydrangea-shaped BiOBr@FAT-NF-1:

[0042] Bi(NO3)3·5H2O (2.42 g, 5 mmol) and KBr (0.59 g, 5 mmol) were dissolved in 60 mL of a 1:1 mixture of 2-methoxyethanol and ethylene glycol and stirred for 30 minutes. The resulting solution and the cleaned needle-shaped NF precursor block were transferred to a 100 mL polytetrafluoroethylene-lined autoclave and subjected to a hydrothermal reaction at 110 °C for 8 hours. After the reaction was completed, the NF precursor block was rinsed with deionized water and then dried in an oven at 60 °C for 6 hours to obtain the photoanode.

[0043] Example 2

[0044] Preparation of metal-doped needle-like precursors using nickel foam as a substrate: Same as Example 1.

[0045] Preparation of Erycibe flower-like BiOBr@FAT-NF-2

[0046] First, Bi(NO3)3·5H2O (0.97 g, 2 mmol) was dissolved in 30 mL of 2-methoxyethanol under stirring for 30 minutes. Then, hexadecyltrimethylammonium bromide (CTAB) (1.093 g, 3 mmol) and 10 mg PVP were dissolved in 30 mL of 2-methoxyethanol, and the mixture was stirred for another 30 minutes. The resulting solution was then added dropwise to the CTAB-PVP mixture, and the mixture was stirred again for 30 minutes. The mixture was then transferred to a 100 mL PTFE-lined stainless steel autoclave and subjected to a hydrothermal reaction at 140 °C for 6 hours. After the reaction was complete, the block was rinsed with deionized water and then dried in a 60 °C oven for 6 hours to obtain the photoanode.

[0047] Example 3

[0048] Preparation of metal-doped needle-like precursors using nickel foam as a substrate: Same as Example 1.

[0049] Preparation of cockscomb-shaped BiOBr@FAT-NF-3

[0050] Bi(NO3)3·5H2O (0.7275 g, 1.5 mmol) was slowly added to a 64 mL mixture of purified water and 2-methoxyethanol (1:1) containing CTAB (0.547 g, 1.5 mmol), and stirred at room temperature for 1 hour. The mixture was then transferred to a 100 mL PTFE-lined stainless steel autoclave and subjected to a hydrothermal reaction at 160 °C for 12 hours. After the reaction was complete, the block was rinsed with deionized water and then dried in a 60 °C oven for 6 hours to obtain the photoanode.

[0051] Test Example 1:

[0052] XRD tests were performed on the BiOBr@FAT-NF-1, BiOBr@FAT-NF-2, and BiOBr@FAT-NF-3 samples from Examples 1-3, respectively. The test results are as follows: Figure 1 As shown, the experimental results indicate that BiOBr@FAT-NF-1, BiOBr@FAT-NF-2, and BiOBr@FAT-NF-3 all contain BiOBr. Different hydrothermal reaction conditions and different solvent ratios lead to the formation of specific morphologies, which in turn cause changes in the intensity and sharpness of characteristic peaks.

[0053] Test Example 2:

[0054] Scanning electron microscopy (SEM) was performed on the BiOBr@FAT-NF-1, BiOBr@FAT-NF-2, and BiOBr@FAT-NF-3 samples from Examples 1-3. The results are as follows: Figure 2 The images show SEM images of the samples. As can be seen from the images, for different samples, the needle-like structures on the catalyst surface are retained and agglomerated, forming protruding structures with the nickel foam substrate, thereby exposing more active sites and exhibiting different specific morphologies.

[0055] Test Example 3:

[0056] For the BiOBr@FAT-NF-1, BiOBr@FAT-NF-2, and BiOBr@FAT-NF-3 samples from Examples 1-3, the samples were placed in an electrolyte solution containing microplastics and then subjected to dark treatment for 1 h. Subsequently, photocurrent density (LSV) and electrochemical impedance spectroscopy (EIS) performance tests were performed using a three-electrode system. The test results are as follows: Figure 3 As shown, the BiOBr@FAT-NF-3 sample exhibits the best performance, with the highest photocurrent density and the lowest impedance. In particular, this sample shows the most significant increase in photocurrent density under illumination, that is, the highest current density and the lowest impedance under dark conditions, demonstrating excellent photoresponse performance.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing a photoelectric composite material with controllable polymorphs, characterized in that: The method comprises the following steps: The needle-shaped precursor doped with metal is prepared by taking a conductive metal material as a substrate, and then the precursor is taken as a carrier to directively induce BiOBr to grow in situ on the carrier to form different morphologies by adjusting and controlling the hydrothermal reaction conditions and reaction solvents, and the reaction solvents are 2-methoxyethanol or a mixture of 2-methoxyethanol and active media, control agents and surfactants.

2. The method for preparing optoelectronic composite materials with controllable multimorphic shapes according to claim 1, characterized in that: The active media are ethylene glycol, the control agents are polyvinylpyrrolidone, and the surfactants are cetyltrimethylammonium bromide.

3. The method for preparing optoelectronic composite materials with controllable multimorphic shapes according to claim 1, characterized in that: In the photoelectric composite material, the sheet thickness of BiOBr is 50-100 nm, and the assembly diameter is 1-3 microns.

4. The method for preparing optoelectronic composite materials with controllable multimorphic shapes according to claim 1, characterized in that: The method comprises the following steps: S1, a needle-shaped precursor doped with metal is prepared by taking a conductive metal material as a substrate; S2-1, a photoelectric composite material in the shape of a globular flower is prepared: Bi(NO3)3·5H2O and KBr are dissolved in a mixed solution of 2-methoxyethanol and active media to be stirred uniformly, and the obtained solution is subjected to a hydrothermal reaction with the dried needle-shaped precursor; S2-2, a photoelectric composite material in the shape of a thistle flower is prepared: Bi(NO3)3·5H2O is dissolved in a mixed solution of a control agent and ethylene glycol, and a surfactant is added to be stirred uniformly, and the obtained solution is subjected to a hydrothermal reaction with the dried needle-shaped precursor; S2-3, a photoelectric composite material in the shape of a cockscomb flower is prepared: Bi(NO3)3·5H2O and a surfactant are dissolved in a 2-methoxyethanol aqueous solution to be stirred uniformly, and the obtained solution is subjected to a hydrothermal reaction with the dried needle-shaped precursor.

5. The method for preparing optoelectronic composite materials with controllable multimorphology according to claim 4, characterized in that: In step S2-1, the mass ratio of Bi(NO3)3·5H2O to KBr is 3.5-4.5:1, and the mass ratio of 2-methoxyethanol to active media is 1:

1.

6. The method for preparing optoelectronic composite materials with controllable multimorphology according to claim 4, characterized in that: In step S2-2, the mass ratio of Bi(NO3)3·5H2O to the surfactant is 0.8-1:1, and the mass ratio of Bi(NO3)3·5H2O to the control agent is 90-106:

1.

7. The method for preparing optoelectronic composite materials with controllable multimorphic shapes according to claim 4, characterized in that: In step S2-3, the mass ratio of Bi(NO3)3·5H2O to the surfactant is 3.5-4.5:

1.

8. The method for preparing optoelectronic composite materials with controllable multimorphic shapes according to claim 4, characterized in that: The temperature of the hydrothermal reaction is 100-180℃, and the hydrothermal reaction time is 5-15 hours, and the morphology of the photoelectric composite material can be controlled by controlling the temperature and reaction time of the hydrothermal reaction.

9. The method for preparing photoelectric composite materials with controllable multimorphic shapes according to claim 4, characterized in that: In step S1, a nickel foam-based needle-shaped photoelectric composite material is prepared by taking a nickel foam as a substrate and doping with Fe, Ag and Ti.

10. A BiOBr-based photoanode, characterized in that: The method is prepared by any one of claims 1-9.

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