Preparation method and application of BiOBr / LaNiO3 nanofiber composite photocatalyst

Abstract

The invention discloses a preparation method of a BiOBr / LaNiO3 nanofiber composite photocatalyst, which is characterized in that a perovskite material LaNiO3 prepared by electrostatic spinning is used as a carrier, and BiOBr is loaded on the fiber surface by a solvothermal method to form a heterojunction structure. According to the composite material, separation of photon-generated carriers is promoted through heterojunction of BiOBr and LaNiO3 nanofibers, and the catalytic activity under visible light is remarkably improved. The invention further discloses application of the prepared BiOBr / LaNiO3 nanofiber composite photocatalyst in degradation of rhodamine B. The degradation efficiency of the BiOBr / LaNiO3 nanofiber composite photocatalyst on rhodamine B can reach 93% within 90 min, and after four times of circulation, the composite material shows good circulation stability. The method has the advantages of being low in cost, high in stability, environmentally friendly and the like, and a green solution is provided for organic dye pollution control.

Description

Technical Field

[0001] This invention relates to a method for preparing a BiOBr / LaNiO3 nanofiber composite photocatalyst and its application. Background Technology

[0002] With rapid population growth and industrial development, water pollution has become increasingly severe, causing serious environmental problems and posing a significant threat to people's lives and health. Compared to traditional water pollutant treatment methods, photocatalytic treatment technology has significant advantages. The vast majority of pollutants can be oxidized or reduced by photocatalytic reactions, producing carbon dioxide, water, and other harmless molecules or ions. This treatment method is very environmentally friendly. Furthermore, photocatalytic reactions are not demanding in terms of conditions, have a fast reaction rate, and are easy to control. Driven by light, it can utilize inexhaustible solar energy, thus contributing to energy conservation. Therefore, applying photocatalytic technology to the treatment of water pollutants is an ideal choice with enormous development potential.

[0003] Photocatalysis technology has attracted widespread attention in the fields of new energy and environmental governance due to its green, efficient, and renewable characteristics. Among numerous photocatalytic semiconductor materials, LaNiO3 can improve the separation efficiency and migration rate of photogenerated carriers and enhance the activity of photocatalytic reactions by adjusting its elemental composition and structure to optimize the electronic structure and optical properties of the photocatalyst. Regarding preparation methods, traditional solid-state reaction methods for preparing LaNiO3 face problems such as easy particle agglomeration, uneven particle size distribution, and small specific surface area. In recent years, the electrospinning method for preparing cubic LaNiO3 has been developed, which greatly improves the physicochemical properties of LaNiO3 and promotes its development in the field of catalysis. Furthermore, selecting suitable support materials and constructing novel composite materials can improve the dispersibility of LaNiO3-based catalytic materials and make their structure more stable, thereby comprehensively improving catalytic activity. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing a BiOBr / LaNiO3 nanofiber composite photocatalyst.

[0005] The objective of this invention is achieved through the following technical solution: A method for preparing a BiOBr / LaNiO3 nanofiber composite photocatalyst, comprising the following steps: S1. LaNiO3 nanofibers were obtained by electrospinning. S2. Bismuth nitrate and sodium bromide are dissolved in ethylene glycol methyl ether, and the LaNiO3 nanofibers obtained in S1 are added to carry out a solvothermal reaction to obtain the BiOBr / LaNiO3 nanofiber composite photocatalyst.

[0006] Preferably, step S1 specifically involves: dissolving lanthanum nitrate and nickel acetylacetonate in N,N-dimethylformamide and acetic acid solvent, stirring until homogeneous, then adding polyvinylpyrrolidone and stirring until homogeneous to form a light green transparent sol precursor solution; electrospinning the obtained sol precursor solution to form a nanofiber membrane, and calcining the nanofiber membrane in air to obtain LaNiO3 nanofibers.

[0007] Preferably, the molar ratio of lanthanum nitrate to nickel acetylacetone is 1:1.

[0008] Preferably, the volume ratio of N,N-dimethylformamide to acetic acid is 4:1.

[0009] Preferably, the electrospinning process parameters are: the distance between the needle and the roller is 15cm, and the voltage is 18kV.

[0010] Preferably, the calcination process is as follows: the nanofiber membrane is heated to 600°C at a rate of 2°C / min and held at that temperature for 3 hours.

[0011] Preferably, the molar ratio of bismuth nitrate, sodium bromide and LaNiO3 nanofibers is 6:2:1.

[0012] Preferably, the temperature of the solvothermal reaction in step S2 is 160°C and the reaction time is 5 hours or more.

[0013] And the BiOBr / LaNiO3 nanofiber composite photocatalyst prepared by the above preparation method.

[0014] This invention also discloses the application of the above-mentioned BiOBr / LaNiO3 nanofiber composite photocatalyst in the degradation of Rhodamine B.

[0015] This invention uses LaNiO3, a perovskite material prepared by electrospinning, as a carrier, and loads BiOBr onto the fiber surface via a solvothermal method to form a heterojunction structure. This composite material significantly enhances catalytic activity under visible light by utilizing the heterojunction between BiOBr and LaNiO3 nanofibers to promote the separation of photogenerated carriers. The degradation efficiency of Rhodamine B reaches 93% in 90 minutes, and the composite material exhibits good cycling stability after four cycles.

[0016] The beneficial effects of this invention are: 1. The present invention is prepared by electrospinning, and the diameter of the obtained fiber can reach 500 nm; 2. The BiOBr / LaNiO3 nanofiber composite photocatalyst prepared by solvothermal method significantly inhibited the recombination of photogenerated electrons and holes and promoted the migration of photogenerated electrons between BiOBr and LaNiO3 by the heterojunction structure. 3. This invention uses a solvothermal method, which has the advantages of low temperature and high efficiency, environmental protection and energy saving, and simple equipment; 4. The composite photocatalyst of the present invention, when applied to the removal of Rhodamine B, can efficiently generate holes and superoxide radicals, thereby achieving efficient removal of dye pollutants; The degradation efficiency of the 5 nanofiber photocatalyst remained at around 89% after four cycles of use. Attached Figure Description

[0017] Figure 1 shows the XRD patterns of LaNiO3, BiOBr, and BiOBr / LaNiO3.

[0018] Figure 2 shows the SEM images of LaNiO3, BiOBr, and BiOBr / LaNiO3.

[0019] Figure 3 shows the TG spectra of LaNiO3, BiOBr, and BiOBr / LaNiO3.

[0020] Figure 4 shows the BET spectra of LaNiO3, BiOBr, and BiOBr / LaNiO3.

[0021] Figure 5 shows the XPS spectra of LaNiO3, BiOBr, and BiOBr / LaNiO3.

[0022] Figure 6 shows the removal efficiency of Rhodamine B by LaNiO3, BiOBr, and BiOBr / LaNiO3.

[0023] Figure 7 shows the removal efficiency of Rhodamine B by BiOBr / LaNiO3 at pH=5, 7 and 9.

[0024] Figure 8 shows the removal efficiency of BiOBr / LaNiO3 in deionized water, tap water and river water for Rhodamine B degradation.

[0025] Figure 9 shows the removal efficiency of BiOBr / LaNiO3 after four cycles of degradation of Rhodamine B. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Example 1 This embodiment provides a method for preparing BiOBr / LaNiO3 nanofiber composite photocatalysts, including the following steps: a) Lanthanum nitrate and nickel acetylacetonate were dissolved in N,N-dimethylformamide and acetic acid solvent, stirred evenly, and then polyvinylpyrrolidone was added and stirred for 10 hours to generate a light green transparent sol precursor solution at room temperature.

[0028] According to some preferred embodiments, 4 ml of N,N-dimethylformamide and 1 ml of acetic acid were used as solvents, and 0.866 g of lanthanum nitrate and 0.5858 g of nickel acetylacetonate were added. After stirring evenly, 0.65 g of polyvinylpyrrolidone was added and stirred for 10 h to generate a light green transparent sol precursor solution at room temperature.

[0029] b. Electrospin the obtained sol precursor solution to form a nanofiber membrane. Calcinate the nanofiber membrane in air to 600°C to remove polyvinylpyrrolidone. The large nanofiber membrane breaks into small nanofiber pieces and is then naturally cooled to room temperature. According to some preferred embodiments, to prevent clogging, electrospinning uses a 10ml syringe and a No. 21 needle, with a distance of 15cm between the needle and the roller, a voltage of 18kV, and the formed film is heated to 600℃ at 2℃ / min and held at that temperature for 3 hours.

[0030] c. The calcined nanofiber flakes were added to a polytetrafluoroethylene liner. Bismuth nitrate and sodium bromide were dissolved in ethylene glycol methyl ether and then transferred to a polytetrafluoroethylene liner reactor for a solvothermal reaction for 5 hours. After the reaction was completed, the mixture was repeatedly rinsed with deionized water and then dried in a 60°C oven to obtain LaNiO3 nanofibers modified with bismuth oxybromine nanosheets. Bismuth oxybromine was prepared by the same method without the addition of nanofiber flakes.

[0031] According to some preferred embodiments, 50 mg of calcined nanofiber flakes were added to a polytetrafluoroethylene (PTFE) liner, and 0.4028 g of bismuth nitrate and 0.1157 g of sodium bromide were added to 30 ml of ethylene glycol monomethyl ether. The mixture was then transferred to a PTFE-lined reactor for solvothermal reaction at 160 °C for 5 hours. After the reaction was completed, the mixture was repeatedly rinsed 6 times with deionized water and then dried in a 60 °C oven to obtain LaNiO3 nanofibers modified with bismuth oxybromine nanosheets. Bismuth oxybromine was prepared by the same method without the addition of nanofiber flakes.

[0032] Comparative Example 1 LaNiO3 nanofibers were obtained by following steps a and b of Example 1, while bismuth oxybromide was prepared by step c of Example 1 without the addition of nanofiber flakes.

[0033] Characterization and evaluation of LaNiO3, BiOBr, and BiOBr / LaNiO3 nanofiber sheet photocatalysts: The nanofiber sheet photocatalysts prepared above were subjected to X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TG), specific surface area measurement (BET), X-ray photoelectron spectroscopy (XPS), and photocatalytic performance testing.

[0034] Figure 1 shows the XRD patterns of the photocatalysts prepared in Example 1 and Comparative Example 1. The main diffraction peaks of LaNiO3 are located at 2θ = 23.2◦, 32.8◦, 47.3◦, 58.6◦, and 69.1◦, corresponding to the (101), (110), (202), (300), and (220) crystal planes of LaNiO3, respectively. The XRD patterns of BiOBr / LaNiO3 nanofibers clearly show that they simultaneously contain characteristic peaks of both LaNiO3 and BiOBr. The diffraction peaks at 21.9◦, 25.2◦, 31.8◦, 32.3◦, 46.3◦, 57.3◦, 67.6◦, and 76.9◦ correspond to the (002), (011), (012), (110), (020), (212), (220), and (130) crystal planes of tetragonal BiOBr, respectively. Compared with LaNiO3, the characteristic peak at 32.8◦ of the composite material shifts to a smaller angle, presumably due to the lattice distortion of LaNiO3 caused by the introduction of BiOBr. This further illustrates the interaction between LaNiO3 and BiOBr. Furthermore, no diffraction peaks of other impurities were found in the spectrum of BiOBr / LaNiO3 nanofibers, indicating that BiOBr / LaNiO3 nanofibers were successfully prepared using a solvothermal method with LaNiO3 nanofibers as the carrier.

[0035] Figure 2 shows SEM images of the photocatalyst. Figure 2(a) shows the random distribution of LaNiO3 gel fibers (i.e., the uncalcined LaNiO3 nanofibers obtained by electrospinning in step b of Example 1). The fibers have smooth surfaces, uniform dimensions, and a diameter of approximately 500 nm. Figure 2 (c) and (d) show the calcined LaNiO3 nanofibers. The LaNiO3 gel fibers become smaller after calcination, with a diameter of approximately 250 nm, due to the decomposition and release of organic matter (PVP, acetylacetone ligand) from within the fibers. The sintering and growth of the metal particles results in an uneven fiber surface. Figure 2(b) shows micron-sized BiOBr spheres grown by solvothermal self-assembly. Figures 2(e) and (f) show BiOBr / LaNiO3 nanofibers. After solvothermal treatment, the surface of the LaNiO3 nanofibers is covered with two-dimensional BiOBr nanosheets. Due to the presence of the substrate LaNiO3 nanofibers, BiOBr grows on the fiber surface in a layered structure. The BiOBr coating does not affect the morphology of the LaNiO3 nanofibers, which remain a fibrous structure overall.

[0036] Figure 3 shows the TG spectrum of LaNiO3 gel fibers. The TG-DSC curves from 15-800℃ reveal three distinct weight loss stages. The first stage occurs between 15-200℃, with a weight loss of approximately 18%, primarily due to the evaporation of water and some residual solvents. The second stage occurs between 200-310℃, exhibiting the largest weight loss of 62%, mainly due to the decomposition of polyvinylpyrrolidone. Nitrates and acetylacetone also partially decompose during this stage, a process that is exothermic, as evidenced by strong exothermic peaks in the DSC curve. The final stage occurs between approximately 310-600℃, with a smaller weight loss of only 8.31%, attributed to the removal of some residual components. No further weight loss occurs up to 800℃, resulting in a final total weight loss of 70.31%, yielding LaNiO3 nanofibers.

[0037] Figure 4 shows the BET spectra of the photocatalysts. The adsorption-desorption curves, specific surface area, and pore size distribution of BiOBr, LaNiO3 nanofibers, and BiOBr / LaNiO3 nanofibers were characterized by N2 adsorption tests. As shown in Figure 4(b), according to IUPAC classification, all samples exhibit typical Type IV isotherm characteristics. However, BiOBr generates an H1-type hysteresis loop during desorption, indicating that the mesoporous structure of the material is generated by the accumulation of sheet-like BiOBr particles. LaNiO3 nanofibers and BiOBr / LaNiO3 nanofibers, on the other hand, generate an H3-type hysteresis loop during desorption, indicating that the mesoporous structure of the material is related to the slits formed by fiber accumulation. As shown in Figure 4(a), the pore size is also mainly distributed below 10 nm, proving that BiOBr / LaNiO3 nanofibers are mesoporous. The increased specific surface area of ​​BiOBr / LaNiO3 nanofibers is due to the fact that the one-dimensional structure of LaNiO3 nanofibers provides a good substrate for the growth of sheet-like BiOBr. This allows BiOBr nanosheets to grow uniformly on LaNiO3 nanofibers, effectively increasing the specific surface area, pore volume, and average pore size of the BiOBr / LaNiO3 nanofibers. Compared to LaNiO3 nanofibers, the larger specific surface area of ​​BiOBr / LaNiO3 nanofibers not only provides more active sites but also promotes effective contact between the catalyst and pollutants, thereby accelerating the photocatalytic reaction process and enhancing the photocatalytic effect of the catalyst.

[0038] Figure 5 shows the XPS spectra of the photocatalyst. In Figure 5(a), the complete XPS spectrum shows that Bi, Br, La, Ni, C, and O elements are all present in the sample. Figure 5(b) shows the Bi4f spectra of Examples 2 and 3. The binding energies of BiOBr are 159.45 eV and 164.76 eV, and the binding energies of BiOBr / LaNiO3 are 159.44 eV and 164.75 eV, corresponding to Bi4f7 / 2 and Bi4f5 / 2, respectively. As shown in Figure 5(c), the binding energies of BiOBr are 68.47 eV and 69.51 eV, and the binding energies of BiOBr / LaNiO3 are 68.46 eV and 69.50 eV, corresponding to Br3d5 / 2 and Br3d3 / 2, respectively. In Figure 5(d), the peaks with binding energies of 834.00, 837.59, 851.27, and 854.6 eV are attributed to La3d5 / 2 and La3d3 / 2 in pure LaNiO3, while the peaks with binding energies of 835.30, 838.66, 852.45, and 855.60 eV are attributed to La3d5 / 2 and La3d3 / 2 in BiOBr / LaNiO3. In Figure 5(f), the peaks observed at 850.58 and 862.36 eV are identified as Ni2p3 / 2 and Ni2p1 / 2 in LaNiO3. Furthermore, a satellite peak was detected at 854.27 eV, indicating that the oxidation state of Ni is +3. Compared to the Ni2p peak of LaNiO3, the corresponding Ni2p peak in BiOBr / LaNiO3 is positively shifted to 852.23, 855.58, and 862.38 eV. This indicates that, compared to LaNiO3, the La3d and Ni2p peaks in BiOBr / LaNiO3 shift towards higher binding energies. In Figure 5(e), the two characteristic O1s peaks in LaNiO3 are attributed to lattice oxygen (528.29 eV) and adsorbed oxygen (532.5 eV), respectively, while the two characteristic O1s peaks in BiOBr / LaNiO3 are attributed to lattice oxygen (530.05 eV) and adsorbed oxygen (531.73 eV), respectively. Compared to LaNiO3, the shift of the lattice oxygen peak in BiOBr / LaNiO3 towards higher binding energies indicates an interaction between LaNiO3 and BiOBr. The variation in binding energy among components in a compound material may be caused by strong interactions between semiconductors; an increase or decrease in binding energy implies an increase or decrease in electrons. Strong interactions exist between the interfaces of heterojunction materials, indicating that effective charge transport exists during heterojunction formation.

[0039] Example 2 The photocatalyst prepared in Example 1 of this invention, along with BiOBr powder, LaNiO3 nanofibers, and BiOBr / LaNiO3 prepared in Comparative Example 1, were used to catalyze the degradation of Rhodamine B, with a pollutant concentration of 40 mg / L. A 500 W xenon lamp was used as the visible light source. 40 mg of the prepared photocatalyst was weighed and added to 50 mL of the target degradation product solution. The solution was ultrasonically treated until uniformly dispersed. The suspension was then stirred in the dark for 30 min to reach adsorption-desorption equilibrium. Subsequently, the suspension was placed under a light source, and 2 mL was taken every 15 min. The supernatant was collected by centrifugation, and the absorbance of the supernatant was measured using a UV-Vis spectrophotometer. The concentration change curve of the target degradation product was obtained based on the ratio of the sampled absorbance value to the initial absorbance value.

[0040] Figure 6 shows the removal efficiency of Rhodamine B by photocatalysis. After adding BiOBr powder, LaNiO3 nanofibers, and BiOBr / LaNiO3 to the RhB solution, respectively, the concentration of RhB decreased to varying degrees after dark chamber adsorption, indicating that the samples have a certain adsorption effect on RhB. After 30 minutes of light irradiation, all samples showed a certain degradation ability for RhB, and the concentration of RhB in the solution decreased significantly. The concentration of RhB in the BiOBr-catalyzed degradation solution was approximately 81% of the original solution. The concentration of RhB in the BiOBr / LaNiO3 nanofiber-catalyzed degradation solution was approximately 53% of the original solution.

[0041] After 90 minutes of light irradiation, the concentration of RhB in the catalytic degradation solution of BiOBr was approximately 27% of the original solution, while the concentration of RhB in the catalytic degradation solution of BiOBr / LaNiO3 nanofibers was approximately 6% of the original solution. This indicates that the BiOBr / LaNiO3 nanofiber heterojunction has better photocatalytic activity than BiOBr powder, suggesting that the photocatalytic activity of LaNiO3 nanofibers is greatly improved after modification.

[0042] Example 3 The photocatalytic performance of the material prepared in Example 1 was tested under acidic, neutral, and alkaline conditions, i.e., the pH value of the target degradation product solution was adjusted before adding the catalyst.

[0043] Acidic conditions: Adjust the pH value to approximately 5 using a 10% HCl solution.

[0044] Alkaline conditions: Use 0.1M NaOH solution to adjust the pH value to approximately 9.

[0045] Neutral conditions are left untreated.

[0046] Rhodamine B was selected as the reference, and a 500W xenon lamp was used as the light source for photocatalysis testing. The remaining steps and conditions were the same as in Example 2.

[0047] Figure 7 shows the photocatalytic effect of the photocatalyst prepared in Example 1 on Rhodamine B under pH conditions of 5, 7, and 9. The BiOBr / LaNiO3 nanofibers can drive the photocatalytic reaction under acidic, alkaline, and neutral conditions, with better adsorption and degradation effects under acidic conditions than under neutral and alkaline conditions. This indicates that the BiOBr / LaNiO3 nanofiber photocatalyst has the ability to drive photocatalytic reactions to degrade pollutants in environments with different acidity and alkalinity.

[0048] Example 4 The photocatalytic performance of the solution prepared in Example 1 was tested under deionized water, tap water, and river water conditions, i.e., the water environment of the target degradation product solution was adjusted before adding the catalyst. Rhodamine B was selected as a reference, and a 500W xenon lamp was used as the light source for the photocatalytic test. The remaining steps were the same as in Example 2.

[0049] Figure 8 shows the photocatalytic effect of the photocatalyst prepared in Example 1 on Rhodamine B under deionized water, tap water, and river water conditions. BiOBr / LaNiO3 nanofibers can drive the photocatalytic reaction in all three environments, with better degradation performance in deionized water than in tap water and river water. This indicates that the BiOBr / LaNiO3 nanofiber photocatalyst exhibits 88% degradation performance in tap water and 84% in river water. The slightly lower activity in real-world water environments can be attributed to the presence of chemicals in actual water sources. These results demonstrate that the BiOBr / LaNiO3 nanofiber photocatalyst can be effectively used in various environments.

[0050] Example 5 The BiOBr / LaNiO3 nanofibers prepared in Example 1 were subjected to cyclic testing following the steps in Example 2. After each test, the samples were precipitated, centrifuged, and dried. Rhodamine B was selected as a reference, and a 500W xenon lamp was used as the light source for photocatalysis testing. The remaining steps were the same as in Example 2.

[0051] Figure 9 shows the photocatalytic effect of the photocatalyst prepared in Example 1 on Rhodamine B after four cycles, with efficiencies of 93%, 92%, 90%, and 89%, respectively. These studies indicate that the BiOBr / LaNiO3 nanofiber photocatalyst still has high photocatalytic efficiency after multiple cycles.

[0052] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a BiOBr / LaNiO3 nanofiber composite photocatalyst, characterized in that... The steps include: S1. LaNiO3 nanofibers were obtained by electrospinning. S2. Bismuth nitrate and sodium bromide are dissolved in ethylene glycol methyl ether, and the LaNiO3 nanofibers obtained in S1 are added to carry out a solvothermal reaction to obtain the BiOBr / LaNiO3 nanofiber composite photocatalyst.

2. The preparation method of the BiOBr / LaNiO3 nanofiber composite photocatalyst according to claim 1, characterized in that: Step S1 specifically involves dissolving lanthanum nitrate and nickel acetylacetonate in N,N-dimethylformamide and acetic acid solvent, stirring until homogeneous, then adding polyvinylpyrrolidone and stirring until homogeneous to form a sol precursor solution; electrospinning the obtained sol precursor solution to form a nanofiber membrane, and calcining the nanofiber membrane in air to obtain LaNiO3 nanofibers.

3. The preparation method of the BiOBr / LaNiO3 nanofiber composite photocatalyst according to claim 2, characterized in that: The molar ratio of lanthanum nitrate to nickel acetylacetone is 1:

1.

4. The preparation method of the BiOBr / LaNiO3 nanofiber composite photocatalyst according to claim 2, characterized in that: The volume ratio of N,N-dimethylformamide to acetic acid is 4:

1.

5. The preparation method of the BiOBr / LaNiO3 nanofiber composite photocatalyst according to claim 2, characterized in that: The process parameters for electrospinning are: the distance between the needle and the roller is 15cm, and the voltage is 18kV.

6. The preparation method of the BiOBr / LaNiO3 nanofiber composite photocatalyst according to claim 2, characterized in that: The calcination process is as follows: the nanofiber membrane is heated to 600℃ at a rate of 2℃ / min and held at that temperature for 3 hours.

7. The method for preparing the BiOBr / LaNiO3 nanofiber composite photocatalyst according to any one of claims 1-6, characterized in that: The mass ratio of bismuth nitrate, sodium bromide, and LaNiO3 nanofibers is 6:2:

1.

8. The preparation method of the BiOBr / LaNiO3 nanofiber composite photocatalyst according to claim 7, characterized in that: The temperature of the solvothermal reaction in step S2 is 160℃, and the reaction time is more than 5 hours.

9. The BiOBr / LaNiO3 nanofiber composite photocatalyst prepared by any one of claims 1-8.

10. The application of the BiOBr / LaNiO3 nanofiber composite photocatalyst according to claim 9 in the degradation of Rhodamine B.

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