Synthesis method of hydrangea-like composite photocatalytic material mnCdS / In2S3 / NiAl-LDH
By synthesizing a hydrangea-shaped MnCdS/In2S3/NiAl-LDH composite photocatalyst, the problem of low efficiency of existing photocatalytic materials was solved. By enhancing the light response and electron-hole separation through heterostructure, highly efficient photocatalytic degradation and hydrogen production performance were achieved.
Patent Information
- Application Number
- CN202311259765.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-09-27
- Publication Date
- 2025-12-26
- Estimated Expiration
- 2043-09-27
AI Technical Summary
Existing photocatalytic materials have low efficiency in photocatalytic water splitting for hydrogen production and photocatalytic degradation of pollutants. The high recombination rate of photogenerated electrons and holes leads to insufficient photocatalytic activity.
A two-step hydrothermal method was used to synthesize a hydrangea-shaped MnCdS/In2S3/NiAl-LDH composite photocatalyst. The composite of MnCdS, In2S3 and NiAl-LDH forms a double S-type heterostructure, which enhances the photoresponse range and electron-hole separation efficiency, and provides a new charge transfer pathway.
The composite material significantly improved photocatalytic activity and photocatalytic water splitting hydrogen production performance. Under simulated sunlight and visible light, the degradation effect of organic pollutant crystal violet was significantly improved, and the hydrogen production was 24 times that of the monomer NiAl-LDH. Moreover, the photocatalytic activity remained stable after three cycles.
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Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the field of photocatalytic water splitting and photocatalytic degradation, and particularly relates to a synthesis method of a MnCdS / In2S3 / NiAl-LDH composite photocatalyst. BACKGROUND
[0002] Energy shortage and environmental pollution have become one of the important problems faced by human beings. Photocatalytic technology is considered as an environmentally friendly water pollution treatment technology because of its simple operation, high efficiency and no secondary pollution. Hydrogen, as a renewable energy, has the advantages of storage, transportation, and no pollution to the environment, and is considered as one of the most potential energy sources in the 21st century. Therefore, the development of new photocatalytic water splitting and photocatalytic degradation of pollutants composite materials is crucial. In2S3 has the advantages of narrow band gap, high photosensitivity and photoconductivity, which can effectively improve the photocatalytic activity of the composite material; MnCdS has the advantages of high quantum efficiency, adjustable band gap, simple synthesis process, etc., which is conducive to optimizing the performance of the composite material. The different band gap values and the positions of the conduction band and the valence band of In2S3, MnCdS and NiAl-LDH can prepare photocatalytic materials with S-type heterojunction. The heterojunction helps to provide more active sites, thereby improving the separation efficiency of photo-generated carriers, and further improving the photocatalytic performance of the composite material. SUMMARY
[0003] The application synthesizes the daisy-like MnCdS / In2S3 / NiAl-LDH by a two-step hydrothermal method. First, the combination of MnCdS, In2S3 and NiAl-LDH reduces the band gap value of the material, effectively reduces the combination of photo-generated electrons and holes, enhances the light response range of the composite material, and further increases the photocatalytic activity to a certain extent. Second, the flower-like morphology of MnCdS / In2S3 / NiAl-LDH allows the three components to be in close contact, thereby generating more active sites and having better photocatalytic activity. Third, the combination of MnCdS, In2S3 and NiAl-LDH effectively suppresses the recombination of photo-generated carriers in the composite material, improves the separation efficiency of electrons and holes, and further effectively improves the photocatalytic activity. More importantly, the double S-type heterojunction is formed in the MnCdS / In2S3 / NiAl-LDH composite material, which provides a new way for the photocatalytic reaction process, accelerates the transfer of charge pairs, and suppresses the electron-hole recombination rate, thereby greatly improving the photocatalytic activity and water splitting performance of the catalyst.
[0004] The technical scheme adopted by the present application to solve its technical problems is: a synthesis method of the MnCdS / In2S3 / NiAl-LDH composite photocatalyst, taking indium nitrate (In(NO3)3·4.5H2O) with a mass of 0.1528±0.0005 g, thioacetamide (C2H5NS) with a mass of 0.1352±0.0005 g, nickel nitrate (Ni(NO3)2·H2O) with a mass of 1.7447±0.0005 g, aluminum nitrate (Al(NO3)3·9H2O) with a mass of 0.7503±0.0005 g, urea (CO(NH2)2) with a mass of 2.4024±0.0005 g, and ammonium fluoride (NH4F) with a mass of 0.592±0.0005 g. The above-mentioned medicines are dissolved in 100 mL of deionized water, stirred for 30 min to obtain a light green mixed solution A, and the solution A is transferred to a hydrothermal reaction kettle, and the temperature is programmed to 120 ℃ and kept for 24 h. After the reaction is completed, the obtained precipitate is washed with ethanol and deionized water for 3 times respectively. Put it into a drying oven at a temperature of 60±2 ℃ and dry for 12±0.1 h, take out the obtained product as In2S3 / NiAl-LDH. Take thioacetamide (C2H5NS) with a mass of 2.5±0.0005 g, cadmium acetate (Cd(CH3COO)2·2H2O) with a mass of 2.28±0.0005 g, and manganese acetate (Mn(CH3COO)2·4H2O) with a mass of 0.11±0.0005 g. Dissolve the three in 40 mL of deionized water to obtain solution B, and add the prepared In2S3 / NiAl-LDH to solution B, stir for 30 min to obtain suspension A, and transfer the suspension A to a hydrothermal reaction kettle, and the temperature is programmed to 120 ℃ and kept for 12 h. After the reaction is completed, the obtained precipitate is washed with ethanol and deionized water for 3 times respectively. Put it into a drying oven at a temperature of 60±2 ℃ and dry for 12±0.1 h, take out the obtained product as MnCdS / In2S3 / NiAl-LDH.
[0005] The application has the beneficial effects that: the ball-shaped MnCdS / In2S3 / NiAl-LDH composite photocatalyst is synthesized by a two-step hydrothermal method. The composite material is composed of cubic In2S3, cubic solid solution phase MnCdS and NiAl-LDH. The composite photocatalyst MnCdS / In2S3 / NiAl-LDH maintains a good ball-shaped structure, and has a better photocatalytic effect on organic pollutants crystal violet (CV) under simulated sunlight and visible light compared with direct photolysis and monomer photocatalysis. In addition, the composite catalyst has excellent hydrogen production capacity, and has a high hydrogen production under the irradiation of a 300 W xenon lamp in a solution of Na2S-Na2SO3 as a sacrificial agent. The composite photocatalyst MnCdS / In2S3 / NiAl-LDH is 24 times that of monomer NiAl-LDH within 8 h, and the photocatalytic activity of the composite photocatalyst still remains stable after three cycles, which fully embodies the excellent hydrogen production performance of the prepared catalyst. This is because the three components of MnCdS, In2S3 and NiAl-LDH further improve the photocatalytic performance of the composite material under the synergistic effect, and the double-S type heterojunction structure is formed in the MnCdS / In2S3 / NiAl-LDH composite material, which provides a new way for the photocatalytic reaction process, accelerates the transfer of photo-generated carriers and inhibits the electron-hole recombination rate. BRIEF DESCRIPTION OF DRAWINGS
[0006] The application will be further described below in combination with the drawings and specific embodiments.
[0007] Figure 1 FIG. 1 is a surface morphology diagram of the ball-shaped MnCdS / In2S3 / NiAl-LDH composite photocatalyst.
[0008] Figure 2 FIG. 2 is a microstructure diagram of the ball-shaped MnCdS / In2S3 / NiAl-LDH composite photocatalyst.
[0009] Figure 3 FIG. 3 is an HRTEM photo of the ball-shaped MnCdS / In2S3 / NiAl-LDH composite photocatalyst.
[0010] Figure 4 FIG. 4 is a simulated sunlight catalytic degradation crystal violet reaction rate diagram of direct photolysis, P25, NiAl-LDH, In2S3 / NiAl-LDH and the ball-shaped MnCdS / In2S3 / NiAl-LDH.
[0011] Figure 5 FIG. 5 is a visible light catalytic degradation crystal violet reaction rate diagram of direct photolysis, NiAl-LDH, In2S3 / NiAl-LDH and the ball-shaped MnCdS / In2S3 / NiAl-LDH.
[0012] Figure 6 Figure 6 is a graph of the simulated sunlight catalytic degradation kinetics results of crystal violet by direct photodegradation, P25, NiAl-LDH, In2S3 / NiAl-LDH, and globular MnCdS / In2S3 / NiAl-LDH.
[0013] Figure 7 Figure 7 is a graph of the UV-Vis diffuse absorption spectra of NiAl-LDH, In2S3, MnCdS, In2S3 / NiAl-LDH, and globular MnCdS / In2S3 / NiAl-LDH.
[0014] Figure 8 Figure 8 is a graph of the results of hydrogen production by water photolysis in a Na2S-Na2SO3 solution by P25, NiAl-LDH, In2S3 / NiAl-LDH, and globular MnCdS / In2S3 / NiAl-LDH. DETAILED DESCRIPTION
[0015] Preparation of the ball-shaped MnCdS / In2S3 / NiAl-LDH composite photocatalyst: 99.5% indium nitrate purchased from the National Pharmaceutical Group Chemical Reagent Co., Ltd. was weighed, with a mass of 0.1528 ± 0.0005 g, 99.0% thioacetamide purchased from Tianjin Kemio Chemical Reagent Co., Ltd. was weighed, with a mass of 0.1352 ± 0.0005 g, 98.0% nickel nitrate purchased from Tianjin Guangfu Technology Development Co., Ltd. was weighed, with a mass of 1.7447 ± 0.0005 g, 99.99% aluminum nitrate purchased from Rongen Reagent was weighed, with a mass of 0.7503 ± 0.0005 g, 99.0% urea purchased from Tianjin Tianli Chemicals Ltd. was weighed, with a mass of 2.4024 ± 0.0005 g, and 96.0% ammonium fluoride purchased from Tianjin Kemio Chemical Reagent Co., Ltd. was weighed, with a mass of 0.592 ± 0.0005 g. The above-weighed reagents were dissolved in 100 mL of deionized water, stirred for 30 min to obtain a light green mixed solution A, and the solution A was transferred to a hydrothermal reactor. The temperature was programmed to 120 ℃ in the electric heating air drying oven of Shanghai Yiheng Scientific Instrument Co., Ltd. and kept for 24 h. After the reaction was completed, the obtained precipitate was washed with ethanol and deionized water for 3 times respectively. It was placed in a drying oven at a temperature of 60 ± 2 ℃ and dried for 12 ± 0.1 h. The obtained product was In2S3 / NiAl-LDH. 99.0% thioacetamide purchased from Tianjin Kemio Chemical Reagent Co., Ltd. was weighed, with a mass of 2.5 ± 0.0005 g, 99.5% cadmium acetate purchased from Tianjin Kemio Chemical Reagent Co., Ltd. was weighed, with a mass of 2.28 ± 0.0005 g, and 99.0% manganese acetate purchased from Tianjin Chuyuan Chemical Reagent Co., Ltd. was weighed, with a mass of 0.11 ± 0.0005 g. The three were dissolved in 40 mL of deionized water to obtain solution B, and the prepared In2S3 / NiAl-LDH was added to solution B. After stirring for 30 min, a suspension A was obtained, and the suspension A was transferred to a hydrothermal reactor. The temperature was programmed to 120 ℃ in the electric heating air drying oven of Shanghai Yiheng Scientific Instrument Co., Ltd. and kept for 12 h. After the reaction was completed, the obtained precipitate was washed with ethanol and deionized water for 3 times respectively. It was placed in a drying oven at a temperature of 60 ± 2 ℃ and dried for 12 ± 0.1 h. The obtained product was the ball-shaped MnCdS / In2S3 / NiAl-LDH composite photocatalyst.
[0016] Structure and performance determination of the ball-shaped MnCdS / In2S3 / NiAl-LDH composite photocatalyst:
[0017] I. Surface morphology and microstructure
[0018] The surface morphology and microstructure analysis results of the ball-shaped MnCdS / In2S3 / NiAl-LDH sample are shown in Figure 1 -3.Figure 1 、 2 It can be clearly observed that the sample presents a globular morphology composed of ultrathin nanosheets. Figure 3 It can be clearly observed that the sample presents a globular morphology composed of ultrathin nanosheets.
[0019] II. Photocatalytic performance determination
[0020] The photocatalytic activities of commercial P25, monomer NiAl-LDH, binary In2S3 / NiAl-LDH and globular MnCdS / In2S3 / NiAl-LDH were tested by photocatalytic experiments of degrading organic pollutants crystal violet and splitting water to produce hydrogen.
[0021] 1. Degradation of organic pollutants crystal violet Figure 4 、 Figure 5 It is shown that the globular MnCdS / In2S3 / NiAl-LDH composite material presents the highest photocatalytic activity in degrading crystal violet under simulated sunlight and visible light, far exceeding commercial P25. In addition, the effects of different samples on the degradation rate of crystal violet are shown in Figure 6 According to the experimental data, the formula -ln(C t / C0)=kt+b is used for calculation, where C t is the concentration of dye at t time (mg·L -1 ), C0is the initial concentration of dye (mg·L -1 ), k is the rate constant (min -1 ), and b is the intercept. It can be seen from Figure 6 that -ln(C t / C0) and reaction time t are basically linear, which indicates that the degradation of crystal violet dye follows pseudo-first-order reaction kinetics.
[0022] 2. UV-visible diffuse reflectance absorption spectra are shown in Figure 7 It can be seen from the figure that compared with NiAl-LDH, with the increase of In2S3 content, the absorption edge moves to a longer wavelength region, and obvious absorption enhancement can be detected in the visible light region, which is attributed to the In2S3 and LDH composite. After the composite of MnCdS, the metal ion effect is reduced, the composite material tends to be stable, the absorption edge of MnCdS / In2S3 / NiAl-LDH is the strongest, which is helpful to produce more photo-generated charges, thereby enhancing the photocatalytic ability.
[0023] 3、Photocatalytic hydrogen evolution over P25, NiAl-LDH, In2S3 / NiAl-LDH and globular MnCdS / In2S3 / NiAl-LDH in Na2S+Na2SO3 solution for sacrificial agent. The results are shown in Fig. 3. It is shown that the globular MnCdS / In2S3 / NiAl-LDH composite has the best hydrogen evolution capacity. Figure 8 It is shown that the globular MnCdS / In2S3 / NiAl-LDH composite has the best hydrogen evolution capacity.
Claims
1. Application of hydrangea-like MnCdS / In2S3 / NiAl-LDH photocatalyst in degradation of organic pollutants crystal violet, characterized in that, The synthesis method of the hydrangea-shaped MnCdS / In2S3 / NiAl-LDH photocatalyst Take indium nitrate (In(NO3)3·4.5H2O), the mass is 0.1528±0.0005g, thioacetamide (C2H5NS), the mass is 0.1352±0.0005g, nickel nitrate (Ni(NO3)2·H2O), the mass is 1.7447±0.0005g, aluminum nitrate (Al(NO3)3·9H2O), the mass is 0.7503±0.0005g, urea (CO(NH2)2), the mass is 2.4024±0.0005g, ammonium fluoride (NH4F), the mass is 0.592±0.0005g; the above-mentioned medicines are dissolved in 100mL deionized water, stirred for 30min, and a light green mixed solution A is obtained, and the solution A is transferred to a hydrothermal reaction kettle, and the temperature is programmed to 120℃ and kept for 24h; after the reaction is completed, the obtained precipitate is washed with ethanol and deionized water for 3 times respectively; put into the drying oven at the temperature condition of 60±2℃ and dry for 12±0.1h, the obtained product is In2S3 / NiAl-LDH; take thioacetamide, the mass is 2.5±0.0005g, cadmium acetate, the mass is 2.28±0.0005g, manganese acetate, the mass is 0.11±0.0005g, dissolve them in 40mL deionized water to obtain solution B, and add the prepared In2S3 / NiAl-LDH to solution B, stir for 30min to obtain suspension A, and transfer the suspension A to a hydrothermal reaction kettle, and the temperature is programmed to 120℃ and kept for 12h; after the reaction is completed, the obtained precipitate is washed with ethanol and deionized water for 3 times respectively; put into the drying oven at the temperature condition of 60±2℃ and dry for 12±0.1h, and the obtained product is MnCdS / In2S3 / NiAl-LDH; In the MnCdS / In2S3 / NiAl-LDH, In2S3 is a cubic phase corresponding to (300) crystal face, MnCdS is a cubic solid solution phase corresponding to (101) crystal face, and NiAl-LDH is a hydroalumite phase corresponding to (015) crystal face.