Oxygen-defective Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet-like composite material and its preparation method

Abstract

The application discloses a kind of oxygen defect Cs2NaBiCl6 / Ce2O3 / Bi2O3 flaky composite material, the average diameter of the oxygen defect Cs2NaBiCl6 / Ce2O3 / Bi2O3 flaky composite material is 0.5-1.9 μm;The average thickness of the oxygen defect Cs2NaBiCl6 / Ce2O3 / Bi2O3 flaky composite material is 50-155nm.The application belongs to the field of composite material, more specifically, it is related to a kind of oxygen defect Cs2NaBiCl6 / Ce2O3 / Bi2 O3 flaky composite material and its preparation method.The beneficial effect of the application is to provide a kind of surface oxygen defect Cs2NaBiCl6 / Ce2O3 / Bi2O3 flake composite material and its preparation method combining grinding method and solvothermal method, the crystallization process of second phase in hydrothermal reaction is used, the micro-morphology of material is controlled, the composite material of the application is uniform in size, and the preparation method is good in repeatability, simple in process.

Description

Technical Field

[0001] This invention belongs to the field of composite materials, and more specifically, relates to an oxygen-defective Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet composite material and its preparation method. Background Technology

[0002] Cs₂NaBiCl₆, as a non-toxic halide double perovskite material, possesses advantages such as high photoelectric conversion efficiency, long carrier diffusion length, and tunable band gap, making it promising for broad applications in chemistry, physics, and catalysis, and showing significant potential contribution to carbon neutralization. However, Cs₂NaBiCl₆ prepared by traditional grinding methods suffers from drawbacks such as fewer surface active sites and low charge separation rate, exhibiting lower catalytic activity and making it difficult to apply in water treatment systems.

[0003] The most common modification method for double perovskite systems is rare-earth ion doping, which primarily involves introducing impurity ions into the material to control its optical, electrical, and magnetic properties. In recent years, ion doping technology has received widespread attention for controlling the performance of double perovskites. Various metal ions have been successfully incorporated into halide perovskites, playing a significant role in improving the photoelectric properties and structural stability of the materials. However, ion doping technology suffers from complex preparation processes and high costs. Furthermore, double perovskites typically exhibit a granular structure, and impurity ions contribute relatively little to the control of material morphology. Reports have shown that introducing a second phase to control crystal structure and improve material properties during the preparation of double perovskite systems is a simple and innovative strategy. For example, "X.Gong,X.Zhang,X.Liu,R.Ding,J.Zhang,H.Yin,Z.Zhang,L.Li,J.Xu,J.Hazard.Mater.2021,403,123821" introduced SiO2 to change the growth mode and crystal morphology of Cs2AgInCl6, transforming it from an octahedron to a truncated octahedron. After structural adjustment, the single crystals were dispersed, and the absorption limit was broken.

[0004] Grinding is a method that uses mechanical energy to disrupt the crystal structure of solid reactants, causing steric hindrance dissociation of organic molecules and accelerating the reaction rate. Solvothermal methods are a commonly used method for preparing nanomaterials with strong inclusiveness and controllable product morphology. However, research on how to use grinding and solvothermal methods to improve the performance of double perovskite systems is still limited, and the morphology of double perovskite crystals is subject to many controllable factors during crystal formation, making precise control difficult.

[0005] Chinese patent document CN202011304677.6 discloses a method for preparing a cesium-containing lead-free halide double perovskite material Cs2NaBi1-xSnxCl6-x. The material prepared by this invention has a simple process, high purity, small grain size, excellent fluorescence performance, and good chemical stability. The incorporated Sn... 2+ This material exhibits significantly improved fluorescence performance and other characteristics, making it highly promising for applications. However, the patent does not disclose how to control the morphology of the double perovskite crystals to enhance its performance, nor does it provide any technical insights. Summary of the Invention

[0006] 1. The problem to be solved

[0007] To address the technical problem that the morphology of crystals is subject to many controllable factors and is difficult to control precisely, this invention provides a method for preparing Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet-like composite materials with oxygen-containing defects on the surface by combining grinding and solvothermal methods. The method utilizes the crystallization process of the second phase in the hydrothermal reaction to control the microstructure of the material. The composite material of this invention has uniform size, and the preparation method has good repeatability and simple process.

[0008] 2. Technical Solution

[0009] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0010] The first aspect of this invention provides an oxygen-deficient Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet-like composite material;

[0011] The average diameter of the oxygen-deficient Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet-like composite material is 0.5-1.9 μm;

[0012] The average thickness of the oxygen-defective Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet composite material is 50-155 nm.

[0013] Furthermore, the strongest XRD diffraction peak of the oxygen-defective Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet composite material is located at 2θ = 22.5-23.4°.

[0014] It should be noted that the average diameter and average thickness of the oxygen-defect-containing Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet composite material described herein are measured by: statistically analyzing the average diameter and average thickness of the sheet structure using a SEM image scale; specifically, the average diameter refers to the average value of the maximum lateral dimension of the sheet structure, that is, the average value of the maximum dimension of the sheet structure in any direction; the average thickness refers to the average value of the vertical distance between one surface and another surface of the sheet structure, wherein the one surface and the other surface are nearly parallel.

[0015] A second aspect of the present invention provides a method for preparing the aforementioned oxygen-deficient Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet-like composite material, comprising the following steps:

[0016] S1. Mix CsCl, NaCl, BiCl3 and hydroquinone, add ethanol and deionized water dropwise, and grind to obtain powder;

[0017] S2. The powder obtained in step S1 is dried to obtain precursor particles;

[0018] S3. Add the precursor particles, CeCl3·7H2O, tert-butylhydroquinone, 1,4-dimethoxybenzene, citric acid, and dilaurate thiodipropionate from step S2 to a mixture of deionized water, DMF, mannitol, and methanol and stir to obtain a mixed solution.

[0019] S4. Perform a solvothermal reaction on the mixed solution from step S3;

[0020] S5. The heating product from step S4 is centrifuged and dried to obtain an oxygen-defective Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet composite material.

[0021] Since the product needs to contain chloride ions in a corresponding molar ratio, chloride salts are used in step S1 to introduce chloride ions. The dropwise addition of ethanol and deionized water in step S1 is to achieve equilibrium during the dissolution and precipitation of chlorides and to ensure uniform nucleation. The addition of ethanol helps to improve the surface microenvironment. There is no restriction on the order of addition of ethanol and deionized water.

[0022] Furthermore, in step S1, the molar ratio of CsCl, NaCl, BiCl3, and hydroquinone is 2:1:1:(0.005-0.011).

[0023] Furthermore, in step S1, the amount of ethanol added for every 2 mmol CsCl is 20-50 μL; the amount of deionized water added is 5-17 μL.

[0024] Furthermore, in step S1, the conditions for mixing CsCl, NaCl, BiCl3, and hydroquinone include: placing the CsCl, NaCl, BiCl3, and hydroquinone into a mortar and mechanically stirring.

[0025] The DMF is N,N-dimethylformamide.

[0026] Furthermore, in step S1, the grinding conditions include a grinding time of 0.5-1 hour.

[0027] Furthermore, in step S2, the drying conditions include: a drying temperature of 60-80℃ and a drying time of 1-3 hours.

[0028] Furthermore, in step S2, the average diameter of the precursor particles is 2.8-3.5 μm.

[0029] It should be noted that the method for measuring the average diameter of precursor particles as described herein is: to measure the average diameter of the granular structure by SEM image.

[0030] Furthermore, in step S3, the molar ratio of the precursor particles, CeCl3·7H2O, tert-butylhydroquinone, 1,4-dimethoxybenzene, citric acid, and dilaurate thiodipropionate is 1:(0.3-0.51):(0.01-0.035):(0.002-0.005):(0.09-0.2):(0.0008-0.008).

[0031] Furthermore, in step S3, the volume ratio of deionized water, DMF, mannitol, and methanol is 1:(1-1.5):(0.05-0.1):(0.004-0.009).

[0032] Furthermore, in step S3, the stirring conditions include a stirring time of 0.5-1 hour.

[0033] Furthermore, in step S3, the stirring conditions also include: the stirring method is magnetic stirring.

[0034] Furthermore, in step S4, the conditions for the solvothermal reaction include: a heating temperature of 170-190℃ and a heating time of 12-20h.

[0035] Furthermore, in step S4, the conditions for the solvothermal reaction also include: being carried out under closed conditions.

[0036] Furthermore, in step S5, the conditions for centrifugal drying include: a drying temperature of 55-70℃ and a drying time of 6 hours.

[0037] 3. Beneficial effects

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0039] (1) This invention regulates the morphology and composition of the Cs2NaBiCl6 / Ce2O3 / Bi2O3 composite material by adding appropriate amounts of Cs2NaBiCl6 precursor particles, mannitol, methanol, tert-butylhydroquinone, 1,4-dimethoxybenzene, citric acid, and dilauryl thiodipropionate to a solvothermal reaction system. The Cs2NaBiCl6 precursor particles are prepared by grinding. The synergistic effect of hydroquinone, ethanol, deionized water, and drying parameters regulates the microenvironment on the surface of the precursor particles, positively influencing the morphological evolution of subsequent products and the formation of the composite material.

[0040] (2) Hydroquinone is added during the preparation of the composite material of the present invention. Hydroquinone, as a polyphenol compound, has strong antioxidant properties, which ensures the stability of the double perovskite material. The introduction of ethanol and water makes the powder in the system dispersed and uniform, accelerates the grinding and co-crystallization process. The drying parameters ensure the stability of the surface groups. In the preparation of oxygen-deficient Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet-like composites, the introduction of Cs2NaBiCl6 precursor particles with adjustable size serves as a site for solvothermal reactions, providing active sites for effective reactions. Mannitol and methanol construct a reducing environment for the solvothermal reaction, promoting the formation of Ce2O3 on the surface. Tert-butylhydroquinone and 1,4-dimethoxybenzene, as antioxidants, have a strong synergistic effect on other chelating agents. Citric acid can act as a surfactant and pH adjuster, promoting the reaction process and helping to induce the nucleation and growth of Ce2O3 and Bi2O3, generating oxygen-deficient Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet-like composites. Dilauryl thiodipropionate has the functions of anti-oxidation and stabilizing the morphology of the material.

[0041] (3) This invention utilizes a grinding method to prepare Cs2NaBiCl6 precursor particles, and then uses a solvothermal method to introduce a second phase and peel off the precursor particles to form an oxygen-defective Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet-like composite material. In addition, this invention controls the microenvironment on the surface of the precursor particles by designing the addition of reagents in the grinding system, and combines the solution ratio and calcination regime of the subsequent solvothermal reaction system to etch the material surface. Using inexpensive materials, simple preparation process, and controllable process parameters, this invention prepares a product with adjustable morphology, stable performance, high catalytic efficiency, and suitable for industrial application, which has broad application prospects in electrochemical catalysis, upconversion luminescence, sensing and other fields.

[0042] (4) The reaction steps combining grinding and solvothermal methods provided by this invention synthesize oxygen-defect-containing Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet-like composite materials. The average size of the sheets is adjustable. Moreover, the raw materials selected in this invention are inexpensive and have good reproducibility, which is conducive to large-scale production. This is different from the prior art in which a second phase is directly added to the precursor to control the crystal structure of double perovskite (the second phase in the prior art includes: 1. direct doping with metal ions, which is generally controlled by adding volatile salts to the precursor solution to control the crystallization of double perovskite, such as "H.Wu,Y". Wang, A. Liu, J. Wang, BJ Kim, Y. Liu, Y. Fang, X. Zhang, G. Boschloo, EMJ Johansson, Adv. Funct. Mater. 2022, 32, 2109402”; 2. As proposed in the background art of this invention, the introduction of a second-phase solid SiO2) and the significant difference in the synthesis mechanism, the composite material of this invention has a significantly increased specific surface area of ​​thin-film structure, which is beneficial to the catalytic reaction and has good innovation and application value. Attached Figure Description

[0043] Figure 1 The X-ray diffraction (XRD) pattern of the precursor particles Cs2NaBiCl6 synthesized in Example 1 of this invention;

[0044] Figure 2 The image shows a scanning electron microscope (SEM) image of the precursor particles Cs2NaBiCl6 synthesized in Example 1 of this invention.

[0045] Figure 3 The X-ray diffraction (XRD) pattern of the oxygen-defective Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet composite material synthesized in Example 1 of this invention;

[0046] Figure 4 This is a scanning electron microscope (SEM) image of the oxygen-defective Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet-like composite material synthesized in Example 1 of this invention. Detailed Implementation

[0047] It should be noted that when a component is referred to as being "mounted" on another component, it can be directly on the other component or the two components can be integrated as one unit; when a component is referred to as being "connected" to another component, it can be directly connected to the other component or the two components can be integrated as one unit. Furthermore, terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity of description and are not intended to limit the scope of implementation. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the term “and / or” as used herein includes any and all combinations of one or more of the associated listed items.

[0049] Unless otherwise specified in the examples, the procedures should be performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0050] As used herein, the term “about” is used to provide for the flexibility and imprecision associated with a given term, measure, or value. Those skilled in the art can readily determine the degree of flexibility for a particular variable.

[0051] As used herein, “adjacent” means that two structures or elements are close to each other. Specifically, elements identified as “adjacent” may be adjacent or connected. Such elements may also be close to or near each other without necessarily touching. In some cases, the precision of proximity may depend on the specific context.

[0052] As used herein, the term “at least one of…” is intended to be synonymous with “one or more of…”. For example, “at least one of A, B, and C” explicitly includes only A, only B, only C, and combinations thereof.

[0053] Concentration, amount, and other numerical data may be presented in range format herein. It should be understood that such range format is used solely for convenience and brevity and should be flexibly interpreted to include not only the values ​​explicitly stated as the limits of the range, but also all individual values ​​or subranges encompassed within the range, as if each value and subrange were explicitly stated. For example, a range of values ​​from about 1 to about 4.5 should be interpreted to include not only the explicitly stated limits of 1 to 4.5, but also individual numbers (such as 2, 3, 4) and subranges (such as 1 to 3, 2 to 4, etc.). The same principle applies to ranges that describe only a single value, such as “less than about 4.5,” which should be interpreted to include all the aforementioned values ​​and ranges. Furthermore, this interpretation should apply regardless of the breadth of the range or characteristic described.

[0054] Any step described in any method or process claim (e.g., steps S1, S2, S3... or steps (1), (2), (3)... or steps 1), 2), 3)...) may be performed in any order, and is not limited to the order set forth in the claims.

[0055] The limitation of method + function or step + function is used only if all of the following conditions are met in a particular claim: a) it expressly states "a method for..." or "a step for..."; b) it expressly states the corresponding function. The structures, materials, or actions supporting the method + function are expressly described in the description herein. Therefore, the scope of the invention should be determined solely by the appended claims and their legal equivalents, and not by the description and examples given herein.

[0056] The present invention will be further described below with reference to specific embodiments.

[0057] Example 1

[0058] This embodiment provides a method for preparing oxygen-deficient Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet-like composite material, comprising the following steps:

[0059] 1.1 Mix 0.337 g of CsCl, 0.058 g of NaCl, 0.315 g of BiCl3 and 0.0009 g of hydroquinone in a mortar and stir mechanically until homogeneous. Then add 30 μL of ethanol and 10 μL of deionized water dropwise and grind for 0.5 h to obtain a homogeneous powder sample.

[0060] 1.2 The above powder sample was dried at 65℃ for 1.5h to obtain precursor particles with an average diameter of 2.8-3.5μm;

[0061] 1.3 Next, prepare a mixed solvent of 10 mL deionized water, 12 mL DMF, 0.7 mL mannitol and 0.06 mL methanol, and then add 0.711 g of precursor particles, 0.149 g of CeCl3·7H2O, 0.003 g of tert-butylhydroquinone, 0.0005 g of 1,4-dimethoxybenzene, 0.029 g of citric acid and 0.0025 g of dilauryl thiodipropionate, and stir for 0.5 h;

[0062] 1.4 Transfer the above solution to a reaction vessel and react in a sealed container at 180°C for 15 hours;

[0063] 1.5 After centrifugation and washing, the product was dried at 60℃ for 6 hours to obtain a Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet composite material with oxygen-containing defects on the surface.

[0064] The phase structure of the precursor particles is as follows Figure 1 As shown, all diffraction peaks correspond well to the standard card (PDF#70-1420) of Cs2NaBiCl6, and the morphology of the precursor particles is as follows. Figure 2 As shown; the phase structure of the final product is as follows. Figure 3As shown, the diffraction peaks correspond well to the standard cards for Cs2NaBiCl6 (PDF#70-1420), Bi2O3 (PDF#71-0466), and Ce2O3 (PDF#78-0484). The microstructure diagram of the product is shown below. Figure 4 As shown, the average diameter of the surface oxygen-defect Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet composite material obtained by the present invention is 0.5-1.9 μm, and the average thickness is 50-155 nm.

[0065] Compared to particulate composite materials, the micron-sized sheet-like composite material of this invention has a higher aspect ratio, larger specific surface area, more active sites, and is more likely to participate in the reaction. Therefore, with the same catalyst dosage, the sheet-like structure outperforms the particulate structure. Based on the advantages of the sheet-like structure, there is a greater tendency to generate a uniform morphology and tunable size distribution to improve material properties. The technical solution of this invention can precisely generate an oxygen-defective Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet-like composite material with a uniform morphology and tunable size distribution.

[0066] Example 2

[0067] 2.1 Mix 0.337 g of CsCl, 0.058 g of NaCl, 0.315 g of BiCl3 and 0.0006 g of hydroquinone in a mortar and stir mechanically until homogeneous. Then add 20 μL of ethanol and 5 μL of deionized water dropwise and grind for 0.5 h to obtain a homogeneous powder sample.

[0068] 2.2 The above powder sample was dried at 60℃ for 1 h to obtain precursor particles with an average diameter of 2.0-2.9 μm;

[0069] 2.3 Next, a mixed solvent of 10 mL deionized water, 15 mL DMF, 1 mL mannitol and 0.09 mL methanol was prepared, and 0.711 g of precursor particles, 0.186 g of CeCl3·7H2O, 0.005 g of tert-butylhydroquinone, 0.0006 g of 1,4-dimethoxybenzene, 0.038 g of citric acid and 0.0041 g of dilauryl thiodipropionate was added sequentially, and the mixture was stirred for 0.5 h.

[0070] 2.4 Transfer the above solution to a reaction vessel and react in a sealed container at 190°C for 20 hours;

[0071] 2.5 After centrifugation and washing, the product was dried at 60℃ for 6 hours to obtain a Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet composite material with oxygen-containing defects on the surface.

[0072] The Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet-like composite material with oxygen-containing defects on the surface has uniform size and dispersion, with an average diameter of 0.5-0.8 μm and an average thickness of 50-70 nm.

[0073] Example 3

[0074] 3.1 Mix 0.337 g of CsCl, 0.058 g of NaCl, 0.315 g of BiCl3 and 0.0012 g of hydroquinone in a mortar and stir mechanically until homogeneous. Then add 50 μL of ethanol and 17 μL of deionized water dropwise and grind for 0.5 h to obtain a homogeneous powder sample.

[0075] 3.2 The above powder sample was dried at 80℃ for 3h to obtain precursor particles with an average diameter of 3.0-3.9μm;

[0076] 3.3 Next, prepare a mixed solvent of 10 mL deionized water, 10 mL DMF, 0.5 mL mannitol and 0.04 mL methanol, and then add 0.711 g of precursor particles, 0.112 g of CeCl3·7H2O, 0.002 g of tert-butylhydroquinone, 0.0003 g of 1,4-dimethoxybenzene, 0.019 g of citric acid and 0.0005 g of dilauryl thiodipropionate, and stir for 0.5 h;

[0077] 3.4 Transfer the above solution to a reaction vessel and react in a sealed container at 170°C for 12 hours;

[0078] 3.5 After centrifugation and washing, the product was dried at 60℃ for 6 hours to obtain a Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet composite material with oxygen-containing defects on the surface.

[0079] The Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet-like composite material with oxygen-containing defects on the surface has uniform size and dispersion, with an average diameter of 1.5-1.9 μm and an average thickness of 120-155 nm.

[0080] Example 4

[0081] 4.1 Mix 0.337 g of CsCl, 0.058 g of NaCl, 0.315 g of BiCl3 and 0.0006 g of hydroquinone in a mortar and stir mechanically until homogeneous. Then add 20 μL of ethanol and 5 μL of deionized water dropwise and grind for 0.5 h to obtain a homogeneous powder sample.

[0082] 4.2 The above powder sample was dried at 60℃ for 1 h to obtain precursor particles with an average diameter of 2.0-2.9 μm;

[0083] 4.3 Next, prepare a mixed solvent of 10 mL deionized water, 11 mL DMF, 0.9 mL mannitol and 0.05 mL methanol, and then add 0.711 g of precursor particles, 0.152 g of CeCl3·7H2O, 0.002 g of tert-butylhydroquinone, 0.0003 g of 1,4-dimethoxybenzene, 0.022 g of citric acid and 0.0024 g of dilauryl thiodipropionate, and stir for 0.5 h;

[0084] 4.4 Transfer the above solution to a reaction vessel and react in a sealed container at 175°C for 13 hours;

[0085] 4.5 After centrifugation and washing, the product was dried at 60℃ for 6 hours to obtain a Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet composite material with oxygen-containing defects on the surface.

[0086] The Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet-like composite material with oxygen-containing defects on the surface has uniform size and dispersion, with an average diameter of 1.3-1.7 μm and an average thickness of 100-125 nm.

[0087] Example 5

[0088] 5.1 Mix 0.337 g of CsCl, 0.058 g of NaCl, 0.315 g of BiCl3 and 0.0008 g of hydroquinone in a mortar and stir mechanically until homogeneous. Then add 40 μL of ethanol and 10 μL of deionized water dropwise and grind for 0.5 h to obtain a homogeneous powder sample.

[0089] 5.2 The above powder sample was dried at 70℃ for 1.5h to obtain precursor particles with an average diameter of 0-3.9μm;

[0090] 5.3 Next, prepare a mixed solvent of 10 mL deionized water, 10 mL DMF, 0.5 mL mannitol and 0.04 mL methanol, and then add 0.711 g of precursor particles, 0.112 g of CeCl3·7H2O, 0.002 g of tert-butylhydroquinone, 0.0003 g of 1,4-dimethoxybenzene, 0.019 g of citric acid and 0.0005 g of dilauryl thiodipropionate, and stir for 0.5 h;

[0091] 5.4 Transfer the above solution to a reaction vessel and react in a sealed container at 170°C for 12 hours;

[0092] 5.5 After centrifugation and washing, the product was dried at 60℃ for 6 hours to obtain a Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet-like composite material with oxygen-containing defects on the surface.

[0093] The Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet composite material with oxygen-containing defects on the surface has uniform size and dispersion, with an average diameter of 1.5-1.9 μm and an average thickness of 120-155 nm.

[0094] Example 6

[0095] 6.1 Mix 0.337 g of CsCl, 0.058 g of NaCl, 0.315 g of BiCl3 and 0.0012 g of hydroquinone in a mortar and stir mechanically until homogeneous. Then add 50 μL of ethanol and 17 μL of deionized water dropwise and grind for 0.5 h to obtain a homogeneous powder sample.

[0096] 6.2 The above powder sample was dried at 80℃ for 3h to obtain precursor particles with an average diameter of 2.5-3.1μm;

[0097] 6.3 Next, prepare a mixed solvent of 10 mL deionized water, 12 mL DMF, 0.8 mL mannitol and 0.08 mL methanol, and then add 0.711 g of precursor particles, 0.158 g of CeCl3·7H2O, 0.004 g of tert-butylhydroquinone, 0.0005 g of 1,4-dimethoxybenzene, 0.029 g of citric acid and 0.004 g of dilauryl thiodipropionate, and stir for 0.5 h;

[0098] 6.4 Transfer the above solution to a reaction vessel and react in a sealed container at 180°C for 17 hours;

[0099] 6.5 After centrifugation and washing, the product was dried at 60℃ for 6 hours to obtain a Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet composite material with oxygen-containing defects on the surface.

[0100] The Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet-like composite material with oxygen-containing defects on the surface has uniform size and dispersion, with an average diameter of 0.9-1.2 μm and an average thickness of 80-100 nm.

[0101] Comparative Example 1

[0102] 1.1 0.337 g of CsCl, 0.058 g of NaCl, and 0.315 g of BiCl3 were placed in a mortar and mixed. The mixture was mechanically stirred until homogeneous and then ground for 0.5 h to obtain a uniform powder sample.

[0103] 1.2 Same as Example 1;

[0104] 1.3 Same as Example 1;

[0105] 1.4 Same as Example 1;

[0106] 1.5 Same as Example 1;

[0107] The above products were Cs2NaBiCl6 particles, and no Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet-like composite material was formed. This shows that the regulation of the microenvironment on the surface of the precursor particles by hydroquinone, ethanol and deionized water has an important influence on the morphological evolution of subsequent products and the formation of composite materials.

[0108] Comparative Example 2

[0109] 2.1 Same as Example 1;

[0110] 2.2 The above powder sample was dried at 100℃ for 8 hours;

[0111] 2.3 Same as Example 1;

[0112] 2.4 Same as Example 1;

[0113] 2.5 Same as Example 1;

[0114] The above products are Cs2NaBiCl6 particles, and no Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet-like composite material was formed. This shows that the drying regime of the precursor has an important influence on the formation of the composite material.

[0115] Comparative Example 3

[0116] 3.1 Same as Example 1;

[0117] 3.2 Same as Example 1;

[0118] 3.3 Next, prepare a mixed solvent of 10 mL deionized water and 12 mL DMF, and then add 0.711 g of precursor particles, 0.149 g of CeCl3·7H2O, 0.003 g of tert-butylhydroquinone, 0.0005 g of 1,4-dimethoxybenzene, 0.029 g of citric acid and 0.0025 g of dilauryl thiodipropionate, and stir for 0.5 h;

[0119] 3.4 Same as Example 1;

[0120] 3.5 Same as Example 1;

[0121] The above product is an irregularly shaped Cs2NaBiCl6 / CeO2 / Bi2O3 composite material. This shows that the reducing environment of mannitol and methanol is important for the generation of oxygen defects on the material surface and for morphology regulation.

[0122] Comparative Example 4

[0123] 4.1 Same as Example 1;

[0124] 4.2 Same as Example 1;

[0125] 4.3 Next, prepare a mixed solvent of 10 mL deionized water, 12 mL DMF, 0.7 mL mannitol and 0.06 mL methanol, and then add 0.711 g of precursor particles, 0.149 g of CeCl3·7H2O, 0.029 g of citric acid and 0.0025 g of dilauryl thiodipropionate in sequence, and stir for 0.5 h;

[0126] 4.4 Same as Example 1;

[0127] 4.5 Same as Example 1;

[0128] The obtained product is a particulate Cs2NaBiCl6 / Ce2O3 composite material with an average diameter of 3.0-3.5 μm. This shows that tert-butylhydroquinone and 1,4-dimethoxybenzene, as antioxidants, have a strong synergistic effect on other chelating agents and have an important influence on the regulation of material structure in the solvothermal reaction system.

[0129] Comparative Example 5

[0130] 5.1 Same as Example 1;

[0131] 5.2 Same as Example 1;

[0132] 5.3 Next, prepare a mixed solvent of 10 mL deionized water, 12 mL DMF, 0.7 mL mannitol and 0.06 mL methanol, and then add 0.711 g of precursor particles, 0.149 g of CeCl3·7H2O, 0.003 g of tert-butylhydroquinone, 0.0005 g of 1,4-dimethoxybenzene and 0.0025 g of dilauryl thiodipropionate, and stir for 0.5 h;

[0133] 5.4 Same as Example 1;

[0134] 5.5 Same as Example 1;

[0135] The resulting product is a particulate Cs2NaBiCl6 / Ce2O3 / Bi2O3 composite material with an average diameter of 2.8-3.2 μm. This shows that citric acid, as an acidity regulator, has a significant impact on the formation of the plate-like structure in the solvothermal reaction system.

[0136] Comparative Example 6

[0137] 6.1 Same as Example 1;

[0138] 6.2 Same as Example 1;

[0139] 6.3 Next, prepare a mixed solvent of 10 mL deionized water, 12 mL DMF, 0.7 mL mannitol and 0.06 mL methanol, and then add 0.711 g of precursor particles, 0.149 g of CeCl3·7H2O, 0.003 g of tert-butylhydroquinone, 0.0005 g of 1,4-dimethoxybenzene and 0.029 g of citric acid in sequence, and stir for 0.5 h;

[0140] 6.4 Same as Example 1;

[0141] 6.5 Same as Example 1;

[0142] The resulting product is a sheet-like Cs2NaBiCl6 / CeO2 / Bi2O3 composite material with an average diameter of 2.9-3.5 μm and a thickness of 500-700 nm, which demonstrates the antioxidant and morphological stabilizing functions of dilauryl thiodipropionate in the solvothermal reaction.

[0143] Comparative Example 7

[0144] 7.1 Same as Example 1;

[0145] 7.2 Same as Example 1;

[0146] 7.3 Same as Example 1;

[0147] 7.4 Transfer the above solution to a reaction vessel and react in a sealed container at 200°C for 15 hours;

[0148] 7.5 Same as Example 1;

[0149] No flake-like Cs2NaBiCl6 / CeO2 / Bi2O3 composite material was observed in the obtained product. Instead, the product exhibited an irregular flake structure with a coexistence of particles, and the yield was significantly reduced. This indicates that the control of solvothermal reaction parameters has a significant impact on the morphology of the product.

[0150] Comparative Example 8

[0151] 8.1 Same as Example 1;

[0152] 8.2 Same as Example 1;

[0153] 8.3 Same as Example 1;

[0154] 8.4 Transfer the above solution to a reaction vessel and react in a sealed container at 110°C for 12 hours;

[0155] 8.5 Same as Example 1;

[0156] No flake-like Cs2NaBiCl6 / CeO2 / Bi2O3 composite material was observed in the obtained product; instead, the product consisted of irregularly sized particles, indicating that the control of solvothermal reaction parameters has a significant impact on the morphology of the product.

[0157] The above description provides an illustrative overview of the present invention and its embodiments. This description is not restrictive, and the embodiments shown are merely one example of the invention's implementation. Actual implementations are not limited to these examples. Therefore, if those skilled in the art are inspired by this description and design similar implementations and examples without departing from the spirit of the invention, such designs should fall within the scope of protection of the present invention.

Claims

1. A Cs₂NaBiCl₆ / Ce₂O₃ / Bi₂O₃ sheet-like composite material containing oxygen defects, characterized in that, The average diameter of the oxygen-deficient Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet-like composite material is 0.5-1.9 μm; The average thickness of the oxygen-defective Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet composite material is 50-155 nm.

2. The method for preparing oxygen-deficient Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet-like composite material according to claim 1, Its features are, Includes the following steps: S1. Mix CsCl, NaCl, BiCl3 and hydroquinone, add ethanol and deionized water dropwise, and grind to obtain powder; S2. The powder obtained in step S1 is dried to obtain precursor particles; S3. Add the precursor particles, CeCl3·7H2O, tert-butylhydroquinone, 1,4-dimethoxybenzene, citric acid, and dilaurate thiodipropionate from step S2 to a mixture of deionized water, DMF, mannitol, and methanol and stir to obtain a mixed solution. S4. Perform a solvothermal reaction on the mixed solution from step S3; S5. The heating product from step S4 is centrifuged and dried to obtain an oxygen-defective Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet composite material.

3. The method for preparing oxygen-deficient Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet-like composite material according to claim 2, characterized in that, In step S1, the molar ratio of CsCl, NaCl, BiCl3, and hydroquinone is 2:1:1:(0.005-0.011).

4. The method for preparing oxygen-deficient Cs₂NaBiCl₆ / Ce₂O₃ / Bi₂O₃ sheet-like composite material according to claim 2, characterized in that, In step S2, the drying conditions include: a drying temperature of 60-80℃ and a drying time of 1-3 hours.

5. The method for preparing oxygen-deficient Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet-like composite material according to claim 2, characterized in that, In step S2, the average diameter of the precursor particles is 2.8-3.5 μm.

6. The method for preparing oxygen-deficient Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet-like composite material according to any one of claims 2 to 5, characterized in that, In step S3, the molar ratio of the precursor particles, CeCl3·7H2O, tert-butylhydroquinone, 1,4-dimethoxybenzene, citric acid, and dilaurate thiodipropionate is 1:(0.3-0.51):(0.01-0.035):(0.002-0.005):(0.09-0.2):(0.0008-0.008).

7. The method for preparing oxygen-deficient Cs₂NaBiCl₆ / Ce₂O₃ / Bi₂O₃ sheet-like composite material according to claim 6, characterized in that, In step S3, the volume ratio of deionized water, DMF, mannitol, and methanol is 1:(1-1.5):(0.05-0.1):(0.004-0.009).

8. The method for preparing oxygen-defective Cs2NaBiCl6 / Ce2O3 / Bi2O3 sheet-like composite material according to claim 7, characterized in that, In step S4, the conditions for the solvothermal reaction include: a heating temperature of 170-190℃ and a heating time of 12-20h.

9. The method for preparing the oxygen-defective Cs₂NaBiCl₆ / Ce₂O₃ / Bi₂O₃ sheet-like composite material according to claim 8, characterized in that, In step S4, the conditions for the solvothermal reaction further include: being carried out under closed conditions.

10. The method for preparing oxygen-defective Cs₂NaBiCl₆ / Ce₂O₃ / Bi₂O₃ sheet-like composite material according to claim 9, characterized in that, In step S5, the conditions for centrifugal drying include a drying temperature of 55-70℃.

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