A bismuth oxyhalide oxide and its synthesis method and application

Abstract

The present invention discloses a bismuth oxyhalide oxide and its synthesis method and application, which belongs to the technical field of inorganic photocatalytic materials. The chemical formula of the bismuth oxyhalide oxide is KBi 5.4 Ca 0.3 Te 0.3 9F 0.3 Cl 0.7 The present invention designs multi-element substitution in bismuth-based oxides to increase defect centers in the lattice. The coexistence of multiple elements in the lattice greatly increases the absorption range in the visible light range, thereby increasing the efficiency of light absorption, more effectively hindering the recombination of photogenerated charges to avoid the consumption of photogenerated carriers in the recombination process, improving the photon quantum efficiency, and making the bismuth halide oxide have excellent photocatalytic performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of inorganic photocatalytic materials, and specifically relates to a bismuth halide oxide and a synthesis method and application thereof. Background Art

[0002] The photocatalytic reaction of semiconductor materials is the process of converting light energy into chemical energy. The most important photocatalytic applications are environmental remediation and water decomposition to produce hydrogen. In recent years, the application of semiconductor photocatalysts in the photodegradation of organic pollutants has received widespread attention. In the photocatalytic reaction, the separation of photogenerated charges is one of the most important factors that directly affects the photocatalytic efficiency.

[0003] Among photocatalytic materials, bismuth-based oxide materials have been widely reported due to their excellent performance and are one of the most promising photocatalyst candidate materials. 3+ Ions have a unique 6s 2 Lone electron pairs can exert a strong repulsive force on other chemical bonds in the lattice. The hybridization of O-2p and Bi-6s electron orbitals in bismuth-based oxides often reduces the potential energy position in the valence band. Such effects cause huge distortions and polar electric fields in the lattice, and photoinduced charges can effectively promote diffusion / migration. Therefore, the recombination between electrons and holes can be greatly delayed, accelerating charge separation, thereby producing effective photocatalytic activity. Therefore, bismuth-based oxide photocatalysts are one of the current research hotspots in the field of photocatalysis, and there are many categories, such as: Bi2S3, Bi2O3, BiVO4, Bi2O2CO3, Bi2WO6, Bi2MoO6, BiOX (X = Cl, Br, I), etc.

[0004] However, existing bismuth-based oxides also have some shortcomings, such as unstable phase, low light energy utilization, narrow spectral response range, and the recombination rate efficiency of photogenerated carriers in the material is still much greater than its separation rate, resulting in most of the photogenerated carriers being consumed in the recombination process, low photoquantum efficiency, etc., which in turn leads to poor photocatalytic effect. Summary of the invention

[0005] The present disclosure aims to solve at least one of the technical problems existing in the prior art and provide a bismuth oxyhalide oxide and a synthesis method and application thereof.

[0006] In one aspect of the present disclosure, a bismuth oxyhalide oxide is provided, wherein the chemical formula of the bismuth oxyhalide oxide is KBi 5.4 Ca 0.3 Te 0.3 9F 0.3 Cl 0.7 .

[0007] Optionally, the bismuth oxyhalide oxide has a strong absorption property in a wavelength region less than 530 nanometers.

[0008] In another aspect of the present disclosure, a method for synthesizing the oxyhalogenated bismuth oxide as described above is provided, the method comprising:

[0009] According to the molecular formula KBi 5.4 Ca 0.3 Te 0.3 9F 0.3 Cl 0.7 The molar ratio of the elements in the formula is as follows: weigh the compounds containing tellurium element Te and bismuth ion Bi respectively. 3+ Compounds containing calcium ions Ca 2+ The compound is prepared by weighing potassium fluoride and potassium chloride in an excess of 5% of the required amount in the molecular formula as raw materials;

[0010] The bismuth ion Bi 3+ and calcium ions Ca 2+ The compound is dissolved in an appropriate amount of dilute nitric acid solution, citric acid is added, and stirred at a temperature of 60 to 90° C. until it is completely dissolved to form a first transparent solution;

[0011] Dissolve the compound containing tellurium element Te in an appropriate amount of hot water at 60-90°C, add citric acid, and stir thoroughly until it is completely dissolved to form a second transparent solution;

[0012] The first transparent solution and the second transparent solution are slowly mixed at 60 to

[0013] After stirring for 3 to 5 hours at 90°C, the mixture was allowed to stand and dried to obtain a precursor;

[0014] The precursor, the potassium fluoride and the potassium chloride are mixed and ground evenly, and the obtained mixture is calcined in an air atmosphere, cooled, and ground evenly to obtain a halide bismuth oxide material.

[0015] Optionally, the bismuth ion Bi 3+ The compound is bismuth nitrate or bismuth oxide.

[0016] Optionally, the calcium ion Ca 2+ The compound is calcium carbonate.

[0017] Optionally, the compound containing tellurium element Te is telluric acid.

[0018] Optionally, the calcination temperature is 750-850° C., and the calcination time is 3-7 hours.

[0019] Optionally, the amount of citric acid added is 1.0-2.0 wt % of the amount of each reactant in the corresponding reaction process.

[0020] In another aspect of the present disclosure, a use of the bismuth oxyhalide oxide as described above in photocatalysis is proposed, wherein the bismuth oxyhalide oxide can degrade organic pollutants under the irradiation of ultraviolet light-visible light.

[0021] The present invention discloses a bismuth oxyhalide oxide and its synthesis method and application. The chemical formula of the bismuth oxyhalide oxide is KBi 5.4 Ca 0.3 Te 0.3 9F 0.3 Cl 0.7 The present invention designs multi-element substitution in bismuth-based oxides to increase defect centers in the lattice. The coexistence of multiple elements in the lattice greatly increases the absorption range in the visible light range, thereby increasing the efficiency of light absorption, more effectively hindering the recombination of photogenerated charges to avoid the consumption of photogenerated carriers in the recombination process, improving the photon quantum efficiency, and making the bismuth halide oxide have excellent photocatalytic performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 1 is a flowchart of a method for synthesizing bismuth oxyhalide oxide according to an embodiment of the present disclosure;

[0023] Figure 2 KBi prepared in Example 1 of the present disclosure 5.4 Ca 0.3 Te 0.3 9F 0.3 Cl 0.7 X-ray powder diffraction pattern of the sample;

[0024] Figure 3 KBi prepared in Example 1 of the present disclosure 5.4 Ca 0.3 Te 0.3 9F 0.3 Cl 0.7 Scanning electron microscope (SEM) images of the samples;

[0025] Figure 4 KBi prepared in Example 1 of the present disclosure 5.4 Ca 0.3 Te 0.3 9F 0.3 Cl 0.7 UV-visible absorption spectrum of the samples;

[0026] Figure 5 KBi prepared in Example 1 of the present disclosure 5.4 Ca 0.3 Te 0.3 9F0.3 Cl 0.7 The degradation effect of the sample on the organic dye methylene blue under light illumination;

[0027] Figure 6 KBi prepared in Example 2 of the present disclosure 5.4 Ca 0.3 Te 0.3 9F 0.3 Cl 0.7 X-ray powder diffraction pattern of the sample;

[0028] Figure 7 KBi prepared in Example 2 of the present disclosure 5.4 Ca 0.3 Te 0.3 9F 0.3 Cl 0.7 Scanning electron microscope (SEM) images of the samples;

[0029] Figure 8 KBi prepared in Example 2 of the present disclosure 5.4 Ca 0.3 Te 0.3 9F 0.3 Cl 0.7 UV-visible absorption spectrum of the samples;

[0030] Fig. 9 KBi prepared in Example 2 of the present disclosure 5.4 Ca 0.3 Te 0.3 9F 0.3 Cl 0.7 The degradation effect of the sample on the organic dye methylene blue under light illumination;

[0031] Fig.10 KBi prepared in Example 3 of the present disclosure 5.4 Ca 0.3 Te 0.3 9F 0.3 Cl 0.7 X-ray powder diffraction pattern of the sample;

[0032] Fig.11 KBi prepared in Example 3 of the present disclosure 5.4 Ca 0.3 Te 0.3 9F 0.3 Cl 0.7 Scanning electron microscope (SEM) images of the samples;

[0033] Fig.12 KBi prepared in Example 3 of the present disclosure 5.4 Ca 0.3 Te 0.3 9F0.3 Cl 0.7 UV-visible absorption spectrum of the samples;

[0034] Fig.13 KBi prepared in Example 3 of the present disclosure 5.4 Ca 0.3 Te 0.3 9F 0.3 Cl 0.7 The degradation effect of the sample on the organic dye methylene blue under light illumination. DETAILED DESCRIPTION

[0035] In order to enable those skilled in the art to better understand the technical solution of the present disclosure, the present disclosure is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0036] In one aspect of the present disclosure, a bismuth oxyhalide oxide is provided, wherein the chemical formula of the bismuth oxyhalide oxide is KBi 5.4 Ca 0.3 Te 0.3 9F 0.3 Cl 0.7 .

[0037] In this embodiment, by designing multi-element substitution in the bismuth-based oxide and increasing the defect centers in the lattice, the coexistence of multiple elements in the lattice greatly increases the absorption range in the visible light range, thereby increasing the efficiency of light absorption, and more effectively hindering the recombination of photogenerated charges to avoid the consumption of photogenerated carriers in the recombination process, thereby improving the photon quantum efficiency, and making the halogenated bismuth oxide have excellent photocatalytic properties.

[0038] It should be noted that, in this embodiment, the Te 4+ Ions and Bi 3+ Having the same stereoactive lone electron pairs can have a huge impact on the photoelectric properties. For example, making the lattice highly polarizable can significantly reduce the material impedance, improve the separation efficiency and mobility of photogenerated charges, and improve the photocatalytic efficiency.

[0039] It should be further noted that, in this embodiment, the halide ions Cl in the lattice - and F - The presence of can enhance the lattice strength, improve the light absorption of the material, and increase the stability of its physical and chemical properties.

[0040] It is still necessary to explain that the bismuth oxyhalide oxide sample has a strong absorption performance in the wavelength region less than 530 nanometers and can be used as a photocatalytic material. In other words, the bismuth oxyhalide oxide of this embodiment has a wide spectral response range, can degrade organic matter under the irradiation of visible light-ultraviolet light, and has a high light energy utilization rate.

[0041] like Figure 1 As shown, another aspect of the present disclosure provides a method S100 for synthesizing oxyhalogenated bismuth oxide as described above, comprising the following steps S110 to S130:

[0042] S110, according to the molecular formula KBi 5.4 Ca 0.3 Te 0.3 9F 0.3 Cl 0.7 The molar ratio of the elements in the solution is required. Weigh the compound raw materials containing tellurium element Te and bismuth ion Bi separately. 3+ Compound raw materials, calcium ions Ca 2+ The compound raw material is prepared, and potassium fluoride and potassium chloride raw materials are weighed in an excess of 5% of the required amount in the molecular formula.

[0043] It should be noted that the present embodiment does not specifically limit the content of each raw material, and can be selected according to actual needs, and converted according to the molar ratio of each element in the molecular formula. It should be understood that the weighing ratio mentioned in the text requires 5% excess of potassium fluoride and potassium chloride in the molecular formula, which should be that the actual weighing content of potassium fluoride is 1.05 times the theoretical value of the molar amount of the F element calculated according to the molar ratio of each element in the molecular formula, and similarly, the actual weighing content of potassium chloride is 1.05 times the theoretical value of the molar amount of the Cl element calculated according to the molar ratio of each element in the molecular formula.

[0044] It should be further explained that, in this embodiment, for compounds containing tellurium element Te, bismuth ions Bi 3+ Compounds, calcium ions Ca 2+ The compound is not specifically limited, as long as each substance can be dissolved in the corresponding solvent and each substance can react to form the bismuth oxyhalide oxide material.

[0045] In some preferred embodiments, the bismuth ion Bi 3+ The compound is bismuth nitrate Bi(NO3)3·5H2O or bismuth oxide Bi2O3.

[0046] In other preferred embodiments, the calcium ion Ca 2+ The compound is calcium carbonate CaCO3. Of course, other calcium-containing 2+ The compound is not particularly limited.

[0047] In other preferred embodiments, the compound raw material containing tellurium element Te is telluric acid H2TeO4·2H2O.

[0048] It is worth noting that in this embodiment, the Te 6+ After chemical reaction, the Te ions in the final product are reduced to 4+, that is, Te 4+ The form exists in the bismuth oxyhalide oxide product, so that Te 4+ Ions and Bi 3+ The formation of stereoactive lone electron pairs further affects the photoelectric properties of the material.

[0049] S120, the bismuth ion Bi weighed in step S110 3+ and calcium ions Ca 2+ The compound is dissolved in an appropriate amount of dilute nitric acid solution, citric acid is added, and stirred at a temperature of 60 to 90° C. until it is completely dissolved to form a first transparent solution.

[0050] In step S120, the amount of citric acid added is 3+ and calcium ions Ca 2+ 1.0 to 2.0 wt% of the total mass of the compound.

[0051] S130, dissolving the compound raw material containing tellurium element Te in an appropriate amount of hot water at 60-90° C., adding citric acid, and stirring thoroughly until it is completely dissolved to form a second transparent solution.

[0052] In step S130, the amount of citric acid added is 1.0-2.0 wt% of the mass of the compound containing tellurium element Te.

[0053] S140, slowly mixing the first transparent solution obtained in step S120 and the second transparent solution obtained in step S130, stirring for 3 to 5 hours at a temperature of 60 to 90°C, standing, and drying to obtain a fluffy precursor.

[0054] S150, mixing the precursor powder obtained in step S140 and the potassium fluoride and potassium chloride weighed in step S110, grinding them evenly, calcining the obtained mixture in an air atmosphere, cooling naturally, and grinding them evenly to obtain a bismuth oxyhalide oxide material, the chemical formula of which is KBi 5.4 Ca 0.3 Te 0.3 9F 0.3 Cl 0.7 .

[0055] In step S150, the calcination temperature is 750-850°C, and the calcination time is 3-7 hours.

[0056] The material phase results prepared in this embodiment can be referred to Figure 2 , 6 , 10. The diffraction pattern is completely consistent with that of the compound KBi6O9Cl reported in the SpringerMaterials database, which shows that the prepared sample is a single phase with good crystallinity.

[0057] The synthesis process of this embodiment is simple. Precursor oxide powder containing Bi, Ca, and Te elements is synthesized by wet chemical method. Then, potassium fluoride and potassium chloride raw materials are added to the precursor to mix with raw materials containing K, F, and Cl elements. After mixing, the mixture is calcined in an air atmosphere to obtain a pure phase target product with stable physical phase and no waste gas and waste liquid pollution during the synthesis process. In addition, the halogen oxybismuth oxide obtained based on the above synthesis method has high light energy utilization rate, wide spectral response range, good photocatalytic stability, can degrade organic pollutants under visible light irradiation, and has high photocatalytic efficiency. It is an ideal photocatalyst for solving environmental pollution.

[0058] In another aspect of the present disclosure, a use of the bismuth oxyhalide oxide as described above in photocatalysis is provided, wherein the bismuth oxyhalide oxide can degrade organic pollutants under the irradiation of ultraviolet-visible light.

[0059] It should be understood that bismuth oxyhalide oxides have good stability and excellent photocatalytic properties and can degrade organic pollutants under irradiation from ultraviolet light to visible light, and are used to solve environmental pollution problems.

[0060] In some preferred embodiments, the bismuth oxyhalide oxide can degrade organic pollutants in water under the irradiation of ultraviolet light-visible light. For example, organic pollutants such as methylene blue and rhodamine B are within its degradation range.

[0061] The following will further illustrate bismuth oxyhalide oxide and its synthesis method in conjunction with several specific examples:

[0062] It should be noted that the photocatalytic performance of the following embodiments is evaluated by the degradation efficiency of photodegradation of methylene blue. Wherein, in the photocatalytic reaction, the irradiation light source lamp is a 500-watt cylindrical xenon lamp, and the reaction tank is a cylindrical photocatalytic reaction instrument made of borosilicate glass. The light source lamp is inserted into the reaction tank, and condensed water is passed to cool down, and the temperature during the reaction is room temperature. The catalyst dosage is 100 mg, the solution volume is 250 ml, and the concentration of methylene blue is 10 mg / L. The catalyst is placed in the reaction solution, the catalytic time is set to 150 minutes, and the illumination is started after the condensed water is turned on. After illumination, a sample is taken every once in a while, centrifuged, and the supernatant is taken. The absorbance of the methylene blue solution is measured at a wavelength of 663-665 nanometers by a UV-visible spectrophotometer. According to Lambert-Beer's law, the absorbance of the solution is proportional to the concentration, so the absorbance can be used instead of the concentration to calculate the removal rate, which is the removal rate of the methylene blue solution. The calculation formula is as follows: Degradation rate = (1-C / C0) × 100% = (1-A t / A0)×100%, where C0 and C are the concentrations before and after photocatalytic degradation, A0 and A t are the absorbance values ​​at the beginning of degradation and after t minutes of degradation, respectively.

[0063] Example 1

[0064] The synthesis method of bismuth oxyhalide oxide in this example comprises the following steps:

[0065] S1, according to the chemical formula KBi 5.4 Ca 0.3 Te 0.3 9F 0.3 Cl 0.7 Tellurium element Te, bismuth ion Bi 3+ and calcium ions Ca 2+ The molar ratio of bismuth nitrate Bi(NO3)3·5H2O was weighed respectively: 15.19 g, calcium carbonate CaCO3: 0.174 g, telluric acid H2TeO4·2H2O: 0.40 g, potassium fluoride KF: 0.11 g, and potassium chloride KCl: 0.32 g.

[0066] S2. Dissolve the weighed bismuth nitrate and calcium carbonate in an appropriate amount of dilute nitric acid solution, add 0.16 g of citric acid to the solution, and stir at 60° C. until completely dissolved to form a first transparent solution.

[0067] S3. Dissolve the weighed telluric acid in an appropriate amount of hot water at 60°C, and add 0.01 g of citric acid to form a second transparent solution.

[0068] S4. Slowly mix the first transparent solution and the second transparent solution, stir at 60° C. for 5 hours, let stand, and dry to obtain a bulky precursor.

[0069] S5. Add potassium fluoride KF and potassium chloride KCl raw materials to the precursor powder obtained by the above sintering, mix and grind evenly. Calcine the mixture in an air atmosphere at a calcination temperature of 750° C. for 7 hours, cool naturally, and grind evenly to obtain a halogen bismuth oxide material.

[0070] See attached Figure 2 , which is the X-ray powder diffraction pattern of the sample prepared according to the technical solution of Example 1. The experimental pattern has a completely consistent diffraction pattern with the compound KBi6O9Cl reported in the SpringerMaterials database. The results show that the prepared sample is a single phase with good crystallinity.

[0071] See attached Figure 3 , which is a scanning electron microscope image of the sample prepared according to the technical solution of Example 1, from Figure 3 It can be seen that the particle size of the sample is about 100 nanometers and the sample structure is loose;

[0072] See attached Figure 4 , which is the UV-visible absorption spectrum of the sample prepared according to the technical scheme of Example 1, from Figure 4 It can be seen that the sample has strong absorption performance in the wavelength region less than 530 nanometers;

[0073] See attached Figure 5 , which is the degradation curve of the organic dye methylene blue by the sample prepared according to the technical scheme of Example 1. Figure 5 It can be seen that the sample degraded 95% of methylene blue within 150 minutes, indicating that the material prepared in Example 1 has good photocatalytic activity.

[0074] Please continue to see the attached Figure 5 Without adding a photocatalyst, the degradation curve of the organic dye methylene blue basically did not change. Within 150 minutes, the content of methylene blue remained basically unchanged, which fully demonstrated that the material of Example 1 has photocatalytic properties and can decompose methylene blue under ultraviolet-visible light irradiation.

[0075] Example 2

[0076] The synthesis method of bismuth oxyhalide oxide in this example comprises the following steps:

[0077] S1, according to the chemical formula KBi 5.4 Ca 0.3 Te 0.3 9F 0.3 Cl 0.7 Tellurium element Te, bismuth ion Bi 3+ and calcium ions Ca 2+The molar ratio of bismuth oxide Bi2O3 was weighed respectively: 12.66 g, calcium carbonate CaCO3: 0.45 g, telluric acid H2TeO4·2H2O: 1.02 g, potassium fluoride KF: 0.27 g, and potassium chloride KCl: 0.81 g.

[0078] S2. Dissolve the weighed bismuth oxide and calcium carbonate in an appropriate amount of dilute nitric acid solution, add 0.26 g of citric acid to the solution, and stir at 90° C. until completely dissolved to form a first transparent solution.

[0079] S3. Dissolve the weighed telluric acid in an appropriate amount of 90°C hot water, and add 0.02 g of citric acid to form a second transparent solution.

[0080] S4. Slowly mix the first transparent solution and the second transparent solution, stir at 90° C. for 3 hours, let stand, and dry to obtain a bulky precursor.

[0081] S5. Add potassium fluoride KF and potassium chloride KCl raw materials to the precursor powder obtained by the above sintering, mix and grind evenly. Calcine the mixture in an air atmosphere at a calcination temperature of 850° C. for 3 hours, cool naturally, and grind evenly to obtain a halogen bismuth oxide material.

[0082] See attached Figure 6 , which is the X-ray powder diffraction pattern of the sample prepared according to the technical solution of Example 2. The experimental pattern has a completely consistent diffraction pattern with the compound KBi6O9Cl reported in the Springer Materials database. The results show that the prepared sample is a single phase with good crystallinity.

[0083] See attached Figure 7 , which is a scanning electron microscope image of the sample prepared according to the technical solution of Example 2, from Figure 7 It can be seen that the particle size of the sample is about 100 nanometers and the sample structure is loose;

[0084] See attached Figure 8 , which is the UV-visible absorption spectrum of the sample prepared according to the technical scheme of Example 2, from Figure 8 It can be seen that the sample has strong absorption performance in the wavelength region less than 530 nanometers;

[0085] See attached Fig. 9 , which is the degradation curve of the organic dye methylene blue by the sample prepared according to the technical scheme of Example 2. Fig. 9 It can be seen that the sample degraded 95% of methylene blue within 150 minutes, indicating that the material prepared in Example 2 has good photocatalytic activity.

[0086] Please continue to see the attached Fig. 9Without adding a photocatalyst, the degradation curve of the organic dye methylene blue basically did not change. Within 150 minutes, the content of methylene blue remained basically unchanged, which fully demonstrated that the material of Example 2 has photocatalytic properties and can decompose methylene blue under ultraviolet-visible light irradiation.

[0087] Example 3

[0088] The synthesis method of bismuth oxyhalide oxide in this example comprises the following steps:

[0089] S1, according to the chemical formula KBi 5.4 Ca 0.3 Te 0.3 9F 0.3 Cl 0.7 Tellurium element Te, bismuth ion Bi 3+ and calcium ions Ca 2+ The molar ratio of bismuth oxide Bi2O3 was weighed respectively: 8.44 g, calcium carbonate CaCO3: 0.30 g, telluric acid H2TeO4·2H2O: 0.69 g, potassium fluoride KF: 0.19 g, and potassium chloride KCl: 0.0.55 g.

[0090] S2. Dissolve the weighed bismuth oxide and calcium carbonate in an appropriate amount of dilute nitric acid solution, add 0.17 g of citric acid to the solution, and stir at 90° C. until completely dissolved to form a first transparent solution.

[0091] S3. Dissolve the weighed telluric acid in an appropriate amount of 90°C hot water, and add 0.02 g of citric acid to form a second transparent solution.

[0092] S4. Slowly mix the first transparent solution and the second transparent solution, stir at 90° C. for 5 hours, let stand, and dry to obtain a bulky precursor.

[0093] S5. Add potassium fluoride KF and potassium chloride KCl raw materials to the precursor powder obtained by the above sintering, mix and grind evenly. Calcine the mixture in an air atmosphere at a calcination temperature of 800° C. for 5 hours, cool naturally, and grind evenly to obtain a halogen bismuth oxide material.

[0094] See attached Fig.10 , which is the X-ray powder diffraction pattern of the sample prepared according to the technical solution of Example 3. The experimental pattern has a completely consistent diffraction pattern with the compound KBi6O9Cl reported in the Springer Materials database. The results show that the prepared sample is a single phase with good crystallinity.

[0095] See attached Fig.11 , which is a scanning electron microscope spectrum of the sample prepared according to the technical solution of Example 3, from Fig.11 It can be seen that the particle size of the sample is about 100 nanometers and the sample structure is loose;

[0096] See attached Fig.12 , which is the UV-visible absorption spectrum of the sample prepared according to the technical scheme of Example 3, from Fig.12 It can be seen that the sample has strong absorption performance in the wavelength region less than 530 nanometers;

[0097] See attached Fig.13 , which is the degradation curve of the organic dye methylene blue by the sample prepared according to the technical scheme of Example 3. Fig.13 It can be seen that the sample degraded 95% of methylene blue within 150 minutes. The material prepared in Example 3 has good photocatalytic activity.

[0098] Please continue to see the attached Fig.13 Without adding a photocatalyst, the degradation curve of the organic dye methylene blue basically did not change. Within 150 minutes, the content of methylene blue remained basically unchanged, which fully demonstrated that the material of Example 3 has photocatalytic properties and can decompose methylene blue under ultraviolet-visible light irradiation.

[0099] In summary, the results of Examples 1 to 3 show that based on the Te in the bismuth oxyhalide oxide lattice 4+ Ions and Bi 3+ Having the same stereoactive lone electron pair can produce a characteristic polarization effect and have a huge impact on the photoelectric performance, for example, it can significantly reduce the material impedance, improve the charge mobility / mobility, and achieve improved photocatalytic efficiency. At the same time, the presence of halide ions in the lattice can enhance the lattice strength, improve the light absorption of the material, and improve the stability of its physical and chemical properties. Based on the above characteristics, the bismuth halide oxide synthesized in the above embodiment can be used as a photocatalyst, which can degrade organic pollutants under light irradiation from ultraviolet light to visible light, has a good decomposition effect, and can make the organic matter degradation rate reach 95%.

[0100] The present disclosure provides a bismuth oxyhalide oxide and a synthesis method and application thereof, which have the following beneficial effects compared with the prior art:

[0101] First, the bismuth oxyhalide oxide proposed in the present disclosure contains Bi 3+ Ions and Te 4+ Ions, this material has the property of absorbing light, and the lattice has a high degree of polarization, which makes the separation efficiency of photogenerated charges high.

[0102] Second, the Cl in the halogen oxybismuth oxide lattice proposed in the present disclosure - and F -The mixed distribution of ions gives the material good optical activity and physicochemical stability.

[0103] Third, the synthesis method disclosed in the present invention is simple, a pure phase can be obtained, and there is no waste gas or waste liquid pollution during the synthesis process.

[0104] Fourthly, the bismuth oxyhalide oxide disclosed in the present invention can efficiently photocatalytically degrade methylene blue, and is used to solve the problem of environmental pollution.

[0105] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present disclosure, but the present disclosure is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and substance of the present disclosure, and these modifications and improvements are also considered to be within the scope of protection of the present disclosure.

Claims

1. A bismuth oxyhalide oxide, characterized in that: The chemical formula of the bismuth oxyhalide oxide is KBi 5.4 Ca 0.3 Te 0.3 9F 0.3 Cl 0.7 .

2. The bismuth oxyhalide oxide according to claim 1, characterized in that The bismuth oxyhalide oxide has a strong absorption property in a wavelength region less than 530 nanometers.

3. A method for synthesizing bismuth oxyhalide oxide as claimed in claim 1 or 2, characterized in that: The synthesis method comprises: According to the molecular formula KBi 5.4 Ca 0.3 Te 0.3 9F 0.3 Cl 0.7 The molar ratio of the elements in the formula is as follows: weigh the compounds containing tellurium element Te and bismuth ion Bi respectively. 3+ Compounds containing calcium ions Ca 2+ The compound is prepared by weighing 5% excess potassium fluoride and 5% excess potassium chloride as raw materials compared to the total amount required in the molecular formula; The bismuth ion Bi 3+ and calcium ions Ca 2+ The compound is dissolved in an appropriate amount of dilute nitric acid solution, citric acid is added, and stirred at a temperature of 60 to 90° C. until it is completely dissolved to form a first transparent solution; Dissolve the compound containing tellurium element Te in an appropriate amount of hot water at 60-90°C, add citric acid, and stir thoroughly until it is completely dissolved to form a second transparent solution; The first transparent solution and the second transparent solution are slowly mixed, stirred at a temperature of 60 to 90° C. for 3 to 5 hours, allowed to stand, and dried to obtain a precursor; The precursor, the potassium fluoride and the potassium chloride are mixed and ground evenly, and the obtained mixture is calcined in an air atmosphere, cooled, and ground evenly to obtain a halide bismuth oxide material.

4. The synthesis method according to claim 3, characterized in that The bismuth ion Bi 3+ The compound is bismuth nitrate or bismuth oxide.

5. The synthesis method according to claim 3, characterized in that The calcium ion Ca 2+ The compound is calcium carbonate.

6. The synthesis method according to claim 3, characterized in that The compound containing tellurium element Te is telluric acid.

7. The synthesis method according to any one of claims 3 to 6, characterized in that The calcination temperature is 750-850°C, and the calcination time is 3-7 hours.

8. The synthesis method according to any one of claims 3 to 6, characterized in that The amount of citric acid added is 1.0-2.0 wt % of the weight of each reactant in the corresponding reaction process.

9. Use of the bismuth oxyhalide oxide as claimed in claim 1 or 2 in photocatalysis, characterized in that: The bismuth oxyhalide oxide can degrade organic pollutants under the irradiation of ultraviolet light-visible light.

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