A BiOI with iodine deficiency 1-x Rod-shaped materials, their preparation methods and applications

Abstract

The application provides a BiOI with iodine defects 1‑x Rod-like material, preparation method and application thereof. Bismuth nitrate pentahydrate and 1,3,5-benzene tricarboxylic acid are added into methanol in proportion, and a metal organic framework [Bi9(C9H3O6)·9(H2O)9] is synthesized by heating at 100-140 DEG C for 20-24 h; the metal organic framework is mixed with ammonium iodide in proportion, and then is subjected to water bath at 60-100 DEG C for 0.5-1.5 h to derive rod-like BiOI; the obtained BiOI is calcined in a muffle furnace at 350-450 DEG C to obtain the rod-like BiOI material with iodine defects, which is represented as BiOI 1‑x . The material has the rod-like microstructure of the precursor [Bi9(C9H3O6)·9(H2O)9], the axial size is slightly reduced, the diameter of the rod is about 1-2 microns, the length is about 3-8 microns, the surface is rough, and the material has a porous structure. The material can be used as a photocatalyst for degradation of gaseous formaldehyde and liquid tetracycline, and both have excellent degradation performance.

Description

Technical Field

[0001] This invention belongs to the field of photocatalytic degradation of pollutants in water and air, specifically relating to a rod-shaped photocatalyst with iodine defects, its preparation method, and its application. Background Technology

[0002] Formaldehyde is a typical volatile organic compound (VOC) among environmental pollutants, widely present in indoor environments and possessing irritant and carcinogenic properties. Tetracycline, a common broad-spectrum antibiotic, is a frequent water pollutant. Conventional biological treatment technologies used in our daily lives are insufficient to completely degrade tetracycline residues in soil and surface water. Long-term human ingestion may lead to the development of resistance genes, posing a significant threat to the ecological environment. Therefore, research on the efficient removal of formaldehyde from air and tetracycline from water is of strategic significance for achieving sustainable environmental development.

[0003] Among numerous treatment methods, photocatalysis is considered a promising approach for pollutant treatment due to its advantages such as mild reaction conditions, environmental friendliness, and strong oxidation capacity. BiOI is a typical semiconductor photocatalytic material with a unique layered structure and excellent physicochemical properties. It is also low-cost, non-toxic, and corrosion-resistant, giving it inherent advantages in energy conversion and environmental remediation. However, the narrow band gap of BiOI (approximately 1.7-1.9 eV) leads to easy recombination of photogenerated electron-hole pairs, and it suffers from drawbacks such as small specific surface area, nanosheet adhesion, and weak photo-oxidation capacity, severely limiting its application. Metal-organic frameworks (MOFs), as novel porous materials, possess wide band gaps, high surface area, customizable structures, and ultra-high adsorption capacity. While retaining the framework of the MOF material itself, thermal treatment can be used to derive stable and high-performance semiconductor materials, which is an effective way to improve the photocatalytic performance of these materials.

[0004] Doping photocatalysts with other elements, constructing heterojunctions, and introducing defects can effectively modulate the band structure of semiconductor materials, thereby suppressing the recombination tendency of photogenerated electrons / holes and improving the light utilization capacity of semiconductor catalysts, making them more effective at redox reactions against pollutants. Compared to doping and heterojunction methods that require introducing foreign matter to improve performance, introducing defects into the material itself requires lower costs and does not affect the thermal stability of the material, making it a preferred choice for improving semiconductor band structures.

[0005] Chinese patent CN110252353B discloses a preparation process for a ternary heterostructure BiOI / Bi / TiO2 composite photocatalytic material, in which unsaturated Ti exists on the surface of the material. 3+The defect sites enhance the dispersion of BiOI through strong interactions between TiO2 and BiOI, and the in-situ formation of metallic Bi at the contact interface improves the photon yield, giving photogenerated electrons and holes stronger redox capabilities. This invention modulates electron density and improves charge separation and transport in the catalyst by constructing iodine defects in situ. The construction of iodine defects effectively increases the maximum valence band value of BiOI, thereby enhancing its oxidation capacity for pollutants, improving the separation efficiency of photogenerated electrons and holes, and effectively preventing their recombination.

[0006] Chinese patent CN115893489A discloses a method for preparing iodine-deficient bismuth iodide powder by adjusting pH value. This invention, however, controls the iodine content by setting different calcination temperatures. Iodine readily sublimates during heating, making the process simple, highly controllable, and capable of preparing BiOI with varying iodine-deficient contents. 1-x Materials. Furthermore, the materials prepared in this invention are derived from metal-organic frameworks, which retain the framework structure of the metal-organic framework itself, and are porous, stable materials with high adsorption capacity.

[0007] The literature Yan W, Han RS, Yi WZ, Long HZ, Yue P, Chang S, Wei G, Ming CL. Chem. Eng. J, 2019, 375, 121971 describes the preparation of iodine-deficient, irregular Bi7O9I3 nanoparticles assembled from nanosheets using a solvothermal method. These nanoparticles, with a size of 100-300 nm, were used to activate the photodegradation of phenol by persulfate. However, the material prepared in this invention is a metal-organic framework (MOF) derived material with a different composition from the literature, consisting of rod-shaped BiOI nanoparticles rich in iodine defects. 1-x The material has a diameter of about 1-2 μm and a length of about 3-8 μm. It retains the structural advantages of MOFs, with a rod-shaped structure that is not easy to stick together and has a high specific surface area, providing more adsorption active sites and pollutant transport channels.

[0008] Chinese patent CN113735167A discloses a method for preparing iodine-deficient BiO using ethylene glycol, glycerol, and hydrogen peroxide as solvents. 1.2 I 0.6 The microsphere method is used, and the structure of this material differs from that of MOFs. This invention uses only methanol as a solvent to first prepare a [Bi9(C9H3O6)·9(H2O)9] metal-organic framework material with a regular rod-like structure. Then, by controlling the iodine content and calcination temperature, a rod-like BiOI structure rich in iodine defects with variable iodine content is obtained. 1-x Metal-organic framework-derived materials, with iodine defects, possess the ability to efficiently photocatalytically degrade gaseous and liquid-phase pollutants.

[0009] In the literature Zi SL, Gang HH, Kun L, Xue KT, Qian P, Jing H, Min LA, Guo FZ. J. Clean. Prod, 2020, 272, 122892, although a solvothermal method was also used to prepare bismuth-based organic framework precursors, the solvent was mainly the more expensive dimethylformamide (DMF), and the reaction time was 48 hours. This invention uses only methanol as a solvent, shortening the reaction time to 20-24 hours. The rod-shaped structure materials in the literature have a diameter of approximately 10 μm and a length of approximately 10-30 μm, which is much larger than the material of this invention, with a diameter of approximately 1-2 μm and a length of approximately 3-8 μm. Generally, smaller particle sizes result in higher activity while maintaining a stable structure. Furthermore, the literature uses it for the visible light degradation of Rhodamine B, while this invention regulates the iodine defect content, enabling not only photocatalytic degradation of antibiotic pollutants in the liquid phase but also efficient photocatalytic removal of VOCs gaseous pollutants such as formaldehyde. Liquid and gas phases are completely different states; therefore, the mechanisms and pathways of photocatalytic degradation of gaseous VOCs pollutants differ significantly from those of photocatalytic degradation of liquid pollutants. For pollutants with different states, phases, and properties, simply having the same composition does not necessarily improve the photocatalytic degradation performance of the material. Different preparation processes and microstructures are important factors affecting performance. Experimental results demonstrate that the rod-shaped material in this invention effectively disperses the catalyst without agglomeration, greatly increasing the catalyst's specific surface area and allowing for sufficient binding of pollutants to active sites. Furthermore, the introduction of iodine defects effectively enhances the pollutant degradation rate.

[0010] This invention combines the morphological advantages of metal-organic frameworks with the excellent light utilization capabilities of BiOI. It derives metal-organic frameworks with rod-shaped microstructures into BiOI, and adjusts the band structure of BiOI by constructing iodine defects through heat treatment, thereby improving its photocatalytic performance and making it highly active for the photodegradation of formaldehyde and tetracycline. Summary of the Invention

[0011] The purpose of this invention is to provide a BiOI with iodine deficiency. 1-x Rod-shaped materials, and the use of these materials as catalysts for the photocatalytic degradation of gaseous formaldehyde and liquid tetracycline.

[0012] This invention provides a BiOI with iodine deficiency. 1-x The material is characterized by having a rod-shaped microstructure of the precursor [Bi9(C9H3O6)·9(H2O)9]. The rods are about 1-2 μm in diameter and about 3-8 μm in length, and have a relatively rough surface.

[0013] The above-mentioned iodine-deficient BiOI1-x The specific preparation steps for the rod-shaped material are as follows:

[0014] A. At room temperature, bismuth nitrate pentahydrate and 1,3,5-pyromellitic acid were added to methanol in a certain proportion to prepare solution A, wherein the molar ratio of bismuth nitrate pentahydrate to 1,3,5-pyromellitic acid was 1:2-3, and the concentration of bismuth nitrate pentahydrate in solution A was 10-30 mmol / L.

[0015] B. Place the above solution A into a high-temperature reactor lined with polytetrafluoroethylene, heat to 100-140℃ and heat for 20-24 hours; cool to room temperature, centrifuge, wash the obtained precipitate with methanol, and dry at 60-70℃ to prepare a metal-organic framework material [Bi9(C9H3O6)·9(H2O)9]; as a precursor of BiOI, this metal-organic framework material has a rod-like microstructure;

[0016] C. Add the metal-organic framework precursor prepared in step B and ammonium iodide to deionized water in a certain proportion to prepare solution B, wherein the mass ratio of metal-organic framework precursor to ammonium iodide is 1:2-3, and the concentration of ammonium iodide in solution B is 0.1-0.3 mmol / L;

[0017] D. Pour the above solution B into a round-bottom flask, place it in a water bath, heat it to 60-100℃, and heat it for 0.5-1.5h; cool it to room temperature, centrifuge it, wash the obtained precipitate with deionized water, and dry it at 60-70℃ to prepare BiOI material; the material has a rod-shaped microstructure of the precursor [Bi9(C9H3O6)·9(H2O)9], the diameter of the rod is about 1-2μm, the length is about 6-8μm, the surface is slightly rough, and the appearance is dark red powder;

[0018] E. The BiOI material obtained in step D is loaded into a calcining furnace; the temperature is increased to 350-450℃ at a heating rate of 1-5℃ / min and calcined for 1-4 hours, then cooled to room temperature at a cooling rate of 1-5℃ / min to obtain BiOI material with iodine defects, denoted as BiOI. 1-x The material has a rod-shaped microstructure of the precursor [Bi9(C9H3O6)·9(H2O)9], with a slightly reduced axial dimension. The rods are about 1-2 μm in diameter and about 3-8 μm in length. The surface becomes rough, forming a porous structure, and the appearance is a bright yellow powder.

[0019] The principle of this invention is as follows: Bismuth nitrate pentahydrate (a metal salt) and the organic ligand 1,3,5-pyromellitic acid undergo a bridging coordination self-assembly process at a certain temperature to form [Bi9(C9H3O6)·9(H2O)9] with a regular rod-like structure. This is then halogenated with ammonium iodide in a water bath and subsequently calcined at a certain temperature. During this process, iodide ions enter the pores of the metal-organic framework [Bi9(C9H3O6)·9(H2O)9] via chemical adsorption, reacting with O and Bi in the framework to form rod-like BiOI. Subsequently, some iodide ions escape upon heating, leaving vacancies in the BiOI lattice, thus obtaining rod-like iodine-deficient BiOI that retains the precursor structure. 1-x Material.

[0020] Figure 1 The material BiOI prepared in Example 1 1-x The X-ray diffraction pattern shows regular peak intensities, exhibiting characteristic peaks of both tetragonal BiOI and orthorhombic Bi5O7I. This indicates that iodine continuously escapes as the heat treatment temperature increases, proving that the material prepared in this invention is an iodine-deficient BiOI with a bicrystalline phase.

[0021] Figure 3 and Figure 4 These are the metal-organic framework precursor [Bi9(C9H3O6)·9(H2O)9] prepared in Example 1 and the photocatalyst BiOI. 1-x The scanning electron microscope images revealed that the microstructure of [Bi9(C9H3O6)·9(H2O)9] was a regular, smooth rod-like structure, while BiOI... 1-x It also exhibits a relatively complete rod shape, proving that the material prepared in this invention retains the rod-shaped structure derived from the metal-organic framework [Bi9(C9H3O6)·9(H2O)9].

[0022] Beneficial effects of the present invention

[0023] 1. This study is the first to use calcined metal-organic frameworks and ammonium iodide-derived BiOI to prepare iodine-deficient BiOI. 1-x The raw materials used in this method are inexpensive and readily available, resulting in low cost. The synthesis process is convenient, the substances have stable physicochemical properties, and the yield is high.

[0024] 2. Preparation of iodine-deficient BiOI 1-x The photocatalyst has a rod-like structure. The sacrificed metal-organic framework template increases the specific surface area and pore volume of the catalyst, enabling the catalyst to be effectively dispersed without sticking together. This provides more adsorption active sites and pollutant transport channels. Compared with BiOI without iodine defects, its photocatalytic performance is significantly improved. This is attributed to the fact that iodine defects modulate the band position of the semiconductor, accelerating the transfer of photogenerated carriers while suppressing their strong recombination tendency.

[0025] 3. Preparation of iodine-deficient BiOI 1-x Photocatalysts can achieve rapid and efficient degradation of formaldehyde gas and tetracycline solution at light wavelengths < 350 nm. λ Irradiation at wavelengths <780nm for 15 minutes can degrade 74.8% of formaldehyde, and 90 minutes can degrade 91.5% of formaldehyde; at a wavelength of 420nm... λ Irradiation with visible light (<780nm) for 10 minutes can degrade 87.5% of tetracycline, and 60 minutes can degrade 94.6% of tetracycline. Attached Figure Description

[0026] Figure 1 It is the BiOI obtained in Example 1 1-x X-ray diffraction (XRD) pattern of photocatalytic nanomaterials;

[0027] Figure 2 It is the BiOI obtained in Example 1 1-x Electron paramagnetic resonance (EPR) image of photocatalytic nanomaterials;

[0028] Figure 3 This is a scanning electron microscope (SEM) image of the metal-organic framework precursor of Example 1;

[0029] Figure 4 It is the BiOI obtained in Example 1 1-x Scanning electron microscope (SEM) images of photocatalytic nanomaterials;

[0030] Figure 5 It is the metal-organic framework, BiOI and BiOI obtained in Example 1. 1-x UV-Vis diffuse emission pattern of photocatalytic materials;

[0031] Figure 6 It is the metal-organic framework, BiOI and BiOI obtained in Example 1. 1-x Bandgap diagram of photocatalytic materials;

[0032] Figure 7 It is the BiOI obtained in Example 1 1-x Formaldehyde cyclic degradation performance diagram of photocatalytic materials;

[0033] Figure 8 It is the BiOI obtained in Example 1 1-x A graph showing the tetracycline cyclic degradation performance of photocatalytic materials. Detailed Implementation Plan

[0034] Example 1

[0035] A. Weigh 0.485g of bismuth nitrate pentahydrate and 0.630g of 1,3,5-pyromellitic acid, add them to 60mL of methanol, and stir at 600rpm for 30min to obtain a mixed solution for preparing the metal-organic framework [Bi9(C9H3O6)·9(H2O)9].

[0036] B. Place the above solution into a reaction vessel and heat it in a convection oven for 24 hours at a temperature of 120°C. After the reaction is complete, wash the precipitate with methanol, centrifuge to collect the lower precipitate, and dry it at 65°C to obtain the metal-organic framework material.

[0037] C. Weigh 0.50g of metal-organic framework and 1.45g of ammonium iodide, add them to a round-bottom flask containing 50mL of deionized water, heat and stir in a water bath for 1h at 90℃, and wash the precipitate after the reaction with deionized water. Centrifuge and collect the lower precipitate and dry it at 65℃ to obtain BiOI material derived from metal-organic framework material, which is used as calcination precursor.

[0038] D. The calcination precursor obtained in step C is heated to 400℃ in a tube furnace at a heating rate of 2℃ / min for 2 hours, and then cooled to room temperature at a cooling rate of 2℃ / min to obtain BiOI with iodine defects. 1-x Photocatalytic nanomaterials.

[0039] Example 2

[0040] A. Weigh 0.485g of bismuth nitrate pentahydrate and 0.630g of 1,3,5-pyromellitic acid, add them to 60mL of methanol, and stir at 600rpm for 30min to obtain a mixed solution for preparing the metal-organic framework [Bi9(C9H3O6)·9(H2O)9].

[0041] B. Place the above solution into a reaction vessel and heat it in a convection oven for 24 hours at a temperature of 120°C. After the reaction is complete, wash the precipitate with methanol, centrifuge to collect the lower precipitate, and dry it at 65°C to obtain the metal-organic framework material.

[0042] C. Weigh 0.50g of metal-organic framework and 1.45g of ammonium iodide, add them to a round-bottom flask containing 50mL of deionized water, heat and stir in a water bath for 1h at 90℃, and wash the precipitate after the reaction with deionized water. Centrifuge and collect the lower precipitate and dry it at 65℃ to obtain BiOI material derived from metal-organic framework material, which is used as calcination precursor.

[0043] D. The calcination precursor obtained in step C is heated to 350°C in a tube furnace at a heating rate of 2°C / min for 2 hours, and then cooled to room temperature at a cooling rate of 2°C / min to obtain BiOI with iodine defects.1-x Photocatalytic nanomaterials.

[0044] Example 3

[0045] A. Weigh 0.485g of bismuth nitrate pentahydrate and 0.630g of 1,3,5-pyromellitic acid, add them to 60mL of methanol, and stir at 600rpm for 30min to obtain a mixed solution for preparing the metal-organic framework [Bi9(C9H3O6)·9(H2O)9].

[0046] B. Place the above solution into a reaction vessel and heat it in a convection oven for 24 hours at a temperature of 120°C. After the reaction is complete, wash the precipitate with methanol, centrifuge to collect the lower precipitate, and dry it at 65°C to obtain the metal-organic framework material.

[0047] C. Weigh 0.50g of metal-organic framework and 1.45g of ammonium iodide, add them to a round-bottom flask containing 50mL of deionized water, heat and stir in a water bath for 1h at 90℃, and wash the precipitate after the reaction with deionized water. Centrifuge and collect the lower precipitate and dry it at 65℃ to obtain BiOI material derived from metal-organic framework material, which is used as calcination precursor.

[0048] D. The calcination precursor obtained in step C is heated to 450°C for 2 hours in a tube furnace at a heating rate of 2°C / min, and then cooled to room temperature at a cooling rate of 2°C / min to obtain BiOI with iodine defects. 1-x Photocatalytic nanomaterials.

[0049] Example 4

[0050] A. Weigh 0.728 g of bismuth nitrate pentahydrate and 0.946 g of 1,3,5-pyromellitic acid, add them to 80 mL of methanol, and stir at 600 rpm for 30 min to obtain a mixed solution for preparing the metal-organic framework [Bi9(C9H3O6)·9(H2O)9].

[0051] B. Place the above solution into a reaction vessel and heat it in a convection oven for 22 hours at a temperature of 120°C. After the reaction is complete, wash the precipitate with methanol, centrifuge to collect the lower precipitate, and dry it at 60°C to obtain the metal-organic framework material.

[0052] C. Weigh 0.50g of metal-organic framework and 1.05g of ammonium iodide, add them to a round-bottom flask containing 50mL of deionized water, heat and stir in a water bath for 40min at 90℃, and wash the precipitate after the reaction with deionized water. Centrifuge and collect the lower precipitate and dry it at 65℃ to obtain the BiOI material derived from the metal-organic framework material, which is used as a calcination precursor.

[0053] D. The calcination precursor obtained in step C is heated to 400℃ for 2 h in a tube furnace at a heating rate of 2℃ / min, and then cooled to room temperature at a cooling rate of 2℃ / min to obtain BiOI with iodine defects. 1-x Photocatalytic nanomaterials.

[0054] Test Example 1

[0055] The obtained material was placed in a sealed, light-transmitting reactor, and a saturated formaldehyde solution (37%) was added dropwise. The reactor was heated at 60°C for 1 hour to allow complete formaldehyde volatilization. The light source was then turned on, and the remaining formaldehyde content in the reactor was measured every 15 minutes. Experimental parameters: Light source wavelength 350 nm < λ A 300W xenon lamp (CEL-HXF300) with a wavelength of <780nm was used as the light source. The catalyst dosage was 200mg, the reactor volume was 315mL, and the formaldehyde concentration was 5mg / L. The photocatalytic degradation performance of the materials prepared in Examples 1, 2, 3, and 4 was measured under the same experimental conditions, and the results are shown in Table 1.

[0056]

[0057] As shown in Table 1, the catalyst prepared in this invention exhibits excellent photocatalytic degradation performance for formaldehyde. Examples 1, 2, 3, and 4 show excellent photocatalytic degradation performance at a wavelength of 350 nm. λ The photodegradation rates after irradiation for 90 minutes under <780nm light conditions reached 91.5%, 90.2%, 82.3%, and 85.2%, respectively.

[0058] Test Example 2

[0059] The obtained material was placed in a transparent liquid-phase reactor, and a prepared tetracycline solution was added. The mixture was stirred in a dark chamber for 30 minutes to establish adsorption-desorption equilibrium. The light source was then turned on, and 3 mL of solution was taken out every 10 minutes. The resulting solution was then filtered through a 0.45 μm polyethersulfone (PES) membrane, and the remaining tetracycline content in the reactor was measured at 357 nm using a UV-Vis spectrophotometer. Experimental parameters: Light source wavelength 420 nm... λ A 300W xenon lamp (CEL-HXF300) with a wavelength of <780nm was used as the light source. The catalyst dosage was 50mg, the tetracycline dosage was 100mL, and the tetracycline concentration was 10mg / L. The photocatalytic degradation performance of tetracycline by the materials prepared in Examples 1, 2, 3, and 4 was measured under the same experimental conditions, and the results are shown in Table 2.

[0060]

[0061] As shown in Table 2, the catalyst prepared in this invention exhibits good photocatalytic degradation performance for tetracycline. Examples 1, 2, 3, and 4 show good photocatalytic degradation performance at a wavelength of 420 nm. λ The photodegradation rates after irradiation with visible light (<780nm) for 60 min reached 94.6%, 93.9%, 90.1%, and 89.2%, respectively.

[0062] Test Example 3

[0063] The metal-organic framework material obtained in Example 1, BiOI and BiOI 1-x The ultraviolet-visible diffuse reflectance spectrum was measured, and the resulting curve is shown below. Figures 5-6 As shown, where Figure 5 This is the ultraviolet-visible absorption spectrum. Figure 6 For the bandgap width diagram, from Figures 5-6 It can be seen that the defective BiOI provided by this invention 1-x The absorption wavelength and band gap of photocatalytic materials fall between those of other materials. Enhanced absorption in the visible light range facilitates photon utilization, thereby improving photocatalytic performance. The absorption wavelengths of metal-organic frameworks, BiOI, and BiOI were calculated using the transformed Kubelka-Munk function. 1-x The band gaps are 3.53 eV, 2.35 eV, and 1.70 eV, respectively. This demonstrates that the iodine vacancies abundant in the photocatalytic material provided by this invention can be used to rationally control the band structure, thereby improving photocatalytic performance.

[0064] Test Example 4

[0065] BiOI obtained in Example 1 1-x Cyclic stability tests were conducted, and formaldehyde and tetracycline degradation experiments were performed according to the methods in Test Example 1 and Test Example 2, respectively. The degradation experiments were repeated five times, and the resulting degradation efficiency graphs are shown below. Figures 7-8 As shown, where Figure 7 This is a graph showing the cyclic degradation performance of formaldehyde. Figure 8 This is a graph showing the cyclic degradation performance of tetracycline. (From...) Figures 7-8 It can be seen that the photocatalytic material provided by the present invention still maintains a high degradation efficiency after 5 cycles.

Claims

1. A BiOI with iodine deficiency 1-x The method for preparing rod-shaped materials is characterized by: Prepare according to the following steps: A. At room temperature, bismuth nitrate pentahydrate and 1,3,5-pyromellitic acid were added to methanol in a certain proportion to prepare solution A, wherein the molar ratio of bismuth nitrate pentahydrate to 1,3,5-pyromellitic acid was 1:2-3, and the concentration of bismuth nitrate pentahydrate in solution A was 10-30 mmol / L. B. Place the above solution A into a high-temperature reactor with a polytetrafluoroethylene liner, heat to 100-140℃ and heat for 20-24 hours; cool to room temperature, centrifuge, wash the obtained precipitate with methanol, and dry at 60-70℃ to prepare a metal-organic framework material [Bi9(C9H3O6)·9(H2O)9]. C. Add the metal-organic framework material prepared in step B and ammonium iodide to deionized water in a certain proportion to prepare solution B, wherein the mass ratio of metal-organic framework material to ammonium iodide is 1:2-3, and the concentration of ammonium iodide in solution B is 0.1-0.3 mmol / L; D. Pour the above solution B into a round-bottom flask, place it in a water bath, heat it to 60-100℃, and heat it for 0.5-1.5h; cool it to room temperature, centrifuge it, wash the obtained precipitate with deionized water, and dry it at 60-70℃ to prepare BiOI material. E. The BiOI material obtained in step D is loaded into a calcining furnace; the temperature is increased to 350-450℃ at a heating rate of 1-5℃ / min and calcined for 1-4 hours, then cooled to room temperature at a cooling rate of 1-5℃ / min to obtain BiOI material with iodine defects, denoted as BiOI. 1-x .

2. The iodine-deficient BiOI prepared by the method as described in claim 1 1-x Rod-shaped material.

3. The iodine-deficient BiOI as described in claim 2 1-x Application of rod-shaped materials in photocatalytic degradation of pollutants in water or air.

Images