Bi 2 Fe 4 O 9 Composite photocatalyst, preparation method thereof and application

Abstract

The present invention relates to a Bi2Fe4O9 composite photocatalyst, a preparation method thereof and an application thereof. The preparation method includes: mixing an iron salt, a bismuth salt and an alkaline solution and then carrying out a hydrothermal reaction to obtain Bi2Fe4O9 with a hexahedral morphology; mixing the Bi2Fe4O9, a manganese salt and a solution of a first sacrificial agent and then carrying out full-spectrum irradiation to deposit MnO x particles on the surface of the hole-dominated crystal plane of the Bi2Fe4O9 to obtain an MnO x -Bi2Fe4O9 composite material; mixing the MnO x -Bi2Fe4O9 composite material, a gold precursor and a solution of a second sacrificial agent and then carrying out full-spectrum irradiation to deposit nano-gold particles on the surface of the electron-dominated crystal plane of the Bi2Fe4O9 to obtain a Bi2Fe4O9 composite photocatalyst. The Bi2Fe4O9 composite photocatalyst obtained by the preparation method of the present invention has excellent photocatalytic activity and has excellent antibacterial effect when used as an antibacterial agent.

Description

Technical Field

[0001] The present invention relates to the field of photocatalytic materials, and particularly to a Bi 2 Fe 4 O 9 composite photocatalyst and its preparation method and application. Background Art

[0002] Plant diseases caused by fungi can cause serious losses to agricultural production, such as anthracnose, Curvularia leaf spot of maize, scab of wheat, etc. At present, the control of plant fungal diseases mainly relies on chemical pesticides. However, the long-term and large-scale use of chemical pesticides will not only damage the ecological environment and threaten the health of humans and animals, but also lead to the generation of pathogen resistance, making the diseases more difficult to control. Therefore, there is an urgent need for low-toxic, high-efficiency, and environmentally friendly control methods.

[0003] Bi 2 Fe 4 O 9 (Bismuth ferrite) as a photocatalytic material can be used as an antibacterial agent. However, its low ability to separate photogenerated electrons results in low photocatalytic activity and cannot achieve efficient antibacterial effects. Summary of the Invention

[0004] Based on this, in view of the above problems, it is necessary to provide a Bi 2 Fe 4 O 9 composite photocatalyst and its preparation method and application. The composite photocatalyst has excellent photocatalytic activity and excellent antibacterial effects when used as an antibacterial agent.

[0005] The present invention provides a preparation method of a Bi 2 Fe 4 O 9 composite photocatalyst, comprising the following steps:

[0006] Mix an iron salt, a bismuth salt, and an alkaline solution and perform a hydrothermal reaction to obtain Bi 2 Fe 4 O 9 ;

[0007] Mix the Bi 2 Fe 4 O 9 with a solution of a manganese salt and a first sacrificial agent and perform full-spectrum irradiation to deposit MnO x particles on the surface of the crystal plane dominated by holes of the Bi 2 Fe 4 O 9 to obtain MnO x -Bi 2 Fe 4O 9 Composite material;

[0008] Mix the solution of the MnO x -Bi 2 Fe 4 O 9 composite material, the gold precursor, and the second sacrificial agent, and then perform full-spectrum irradiation to deposit gold nanoparticles on the surface of the crystal plane dominated by electrons of the Bi 2 Fe 4 O 9 to obtain a Bi 2 Fe 4 O 9 composite photocatalyst.

[0009] In one embodiment, the morphology of the Bi 2 Fe 4 O 9 is a parallelepiped.

[0010] In one embodiment, the concentration of the alkaline solution is 6 mol / L - 8 mol / L, and the mass ratio of the iron salt, the bismuth salt to the alkaline solution is (2 - 4):(1 - 2):50.

[0011] In one embodiment, the mass ratio of the manganese salt to the Bi 2 Fe 4 O 9 is 0.001:100 - 1:100;

[0012] and / or, the mass ratio of the first sacrificial agent to the Bi 2 Fe 4 O 9 is 1:1 - 2:3.

[0013] In one embodiment, the mass ratio of the gold precursor to the MnO x -Bi 2 Fe 4 O 9 composite material is 1:1000 - 1:100;

[0014] and / or, the mass ratio of the second sacrificial agent to the MnO x -Bi 2 Fe 4 O 9 composite material is 1:10 - 1:5.

[0015] In one embodiment, in the step of mixing the iron salt, the bismuth salt, and the alkaline solution and then performing a hydrothermal reaction, the reaction temperature is 180°C - 220°C, and the reaction time is 12 h - 24 h;

[0016] and / or, in the step of mixing a solution of the Bi 2 Fe 4 O 9 , manganese salt, and a first sacrificial agent and then performing full-spectrum irradiation, the irradiation time is 180 min - 240 min;

[0017] and / or, in the step of mixing a solution of the MnO x -Bi 2 Fe 4 O 9 composite material, a gold precursor, and a second sacrificial agent and then performing full-spectrum irradiation, the irradiation time is 60 min - 120 min.

[0018] In one embodiment, the alkaline solution is selected from at least one of sodium hydroxide solution and potassium hydroxide solution;

[0019] and / or, the iron salt is selected from iron nitrate;

[0020] and / or, the bismuth salt is selected from bismuth nitrate;

[0021] and / or, the manganese salt is selected from manganese nitrate;

[0022] and / or, the solution of the first sacrificial agent is selected from sodium iodate solution;

[0023] and / or, the solution of the second sacrificial agent is selected from methanol solution;

[0024] and / or, the gold precursor is selected from chloroauric acid.

[0025] A Bi 2 Fe 4 O 9 composite photocatalyst obtained by the preparation method of the Bi 2 Fe 4 O 9 composite photocatalyst as described above, the Bi 2 Fe 4 O 9 composite photocatalyst includes Bi 2 Fe 4 O 9 in a hexahedral morphology, and nanogold particles loaded on the surface of the crystal plane dominated by electrons of the Bi 2 Fe 4 O 9 and MnO 2 Fe 4 O 9 particles loaded on the surface of the crystal plane dominated by holes of the Bi x

[0026] In one embodiment, the Bi​2 Fe 4 O 9 has a parallelepiped morphology.

[0027] A Bi as described above 2 Fe 4 O 9 composite photocatalyst is used as an antibacterial agent.

[0028] In the preparation method of the Bi 2 Fe 4 O 9 composite photocatalyst of the present invention, first, Bi 2 Fe 4 O 9 with a hexahedral morphology is formed, and then, through the dual action of a sacrificial agent and full-spectrum irradiation, MnO x and nano-gold particles are respectively and uniformly deposited on the hole-dominated crystal plane surface and the electron-dominated crystal plane surface of Bi 2 Fe 4 O 9 so that the obtained Bi 2 Fe 4 O 9 composite photocatalyst has advantages such as excellent photo-generated electron separation ability and excellent carrier separation efficiency, and thus has excellent photocatalytic activity and excellent antibacterial effect when used as an antibacterial agent. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is an X-ray diffraction pattern, where A, C, and D are the X-ray diffraction patterns of hexahedral Bi 2 Fe 4 O 9 in Example 1, MnO x -Bi 2 Fe 4 O 9 composite material, and Bi 2 Fe 4 O 9 composite photocatalyst in sequence, B is the X-ray diffraction pattern of the AuNPs-Bi 2 Fe 4 O 9 composite material in Comparative Example 1, and E is the scale diagram of Bi 2 Fe 4 O 9 ;

[0030] Figure 2 is a scanning electron microscope image, where a, b, and d are the hexahedral Bi 2 Fe 4 O 9 in Example 1, MnOx -Bi 2 Fe 4 O 9 Composite material, Bi 2 Fe 4 O 9 Scanning electron microscope image of the composite photocatalyst. c is AuNPs-Bi in Comparative Example 1 2 Fe 4 O 9 Scanning electron microscope image of the composite material;

[0031] Figure 3 Are transmission electron microscope images, where a and b are Bi in Example 1 2 Fe 4 O 9 Transmission electron microscope image of the composite photocatalyst. c and d are Bi in Example 1 2 Fe 4 O 9 High-resolution transmission electron microscope image of the composite photocatalyst;

[0032] Figure 4 Are ultraviolet-visible reflection spectra, where F, H, and J are the hexahedral Bi in Example 1 in sequence 2 Fe 4 O 9 MnO x -Bi 2 Fe 4 O 9 Composite material, Bi 2 Fe 4 O 9 Ultraviolet-visible reflection spectrum of the composite photocatalyst. G is AuNPs-Bi in Comparative Example 1 2 Fe 4 O 9 Ultraviolet-visible reflection spectrum of the composite material;

[0033] Figure 5 Are X-ray photoelectron spectroscopy diagrams, where M and K are the hexahedral Bi in Example 1 in sequence 2 Fe 4 O 9 MnO x -Bi 2 Fe 4 O 9 X-ray photoelectron spectroscopy diagram of the composite material. L is AuNPs-Bi in Comparative Example 1 2 Fe 4 O 9 X-ray photoelectron spectroscopy diagram of the composite material;

[0034] Figure 6is a photocurrent diagram, where P, R, and S are, in sequence, the hexahedral-shaped Bi in Example 1 2 Fe 4 O 9 , MnO x -Bi 2 Fe 4 O 9 composite material, the photocurrent diagram of the Bi 2 Fe 4 O 9 composite photocatalyst, and Q is the photocurrent diagram of the AuNPs-Bi 2 Fe 4 O 9 composite material in Comparative Example 1;

[0035] Figure 7 is an impedance diagram, where T, V, and W are, in sequence, the hexahedral-shaped Bi in Example 1 2 Fe 4 O 9 , MnO x -Bi 2 Fe 4 O 9 composite material, the impedance diagram of the Bi 2 Fe 4 O 9 composite photocatalyst, and U is the impedance diagram of the AuNPs-Bi 2 Fe 4 O 9 composite material in Comparative Example 1;

[0036] Figure 8 is an antibacterial diagram under different illumination times, where X is the antibacterial diagram of the hexahedral-shaped Bi 2 Fe 4 O 9 illuminated for 0 min, 15 min, 30 min, 45 min, and 60 min respectively, Z is the antibacterial diagram of the MnO x -Bi 2 Fe 4 O 9 composite material illuminated for 0 min, 15 min, 30 min, 45 min, and 60 min respectively, e is the antibacterial diagram of the Bi 2 Fe 4 O 9 composite photocatalyst illuminated for 0 min, 15 min, 30 min, 45 min, and 60 min respectively, and Y is the AuNPs-Bi in Comparative Example 1 2 Fe 4 O 9Antibacterial diagrams of the composite material under illumination for 0 min, 15 min, 30 min, 45 min, and 60 min respectively. Detailed implementation manners

[0037] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below with reference to relevant embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0039] Bi provided by the present invention 2 Fe 4 O 9 Preparation method of a composite photocatalyst, comprising the following steps:

[0040] S1, mixing an iron salt, a bismuth salt, and an alkaline solution and then performing a hydrothermal reaction to obtain Bi 2 Fe 4 O 9 ;

[0041] S2, mixing the Bi 2 Fe 4 O 9 with a solution of a manganese salt and a first sacrificial agent and then performing full-spectrum irradiation to deposit MnO x particles on the surface of the crystal plane dominated by holes of the Bi 2 Fe 4 O 9 to obtain a MnO x -Bi 2 Fe 4 O 9 composite material;

[0042] S3, mixing the MnO x -Bi 2 Fe 4 O 9 composite material with a solution of a gold precursor and a second sacrificial agent and then performing full-spectrum irradiation to deposit nano-gold particles on the surface of the crystal plane dominated by electrons of the Bi 2 Fe 4 O 9 to obtain Bi 2 Fe4 O 9 Composite photocatalyst.

[0043] In step S1, using iron salt and bismuth salt as precursors, through hydrothermal reaction, the iron salt and bismuth salt are induced to react to form Bi with a hexahedral morphology 2 Fe 4 O 9 , and the Bi with a hexahedral morphology 2 Fe 4 O 9 has an orthorhombic structure with the Pbam space group, and its unit is composed of two formula units, which can be described as a column of edge-sharing FeO 4 tetrahedrons and FeO 6 octahedrons connected by bismuth atoms. The Bi with a hexahedral morphology 2 Fe 4 O 9 has different crystal planes, and each crystal plane is dominated by electrons and holes respectively, so it has stronger visible light absorption and a smaller band gap.

[0044] In one embodiment, the morphology of the Bi 2 Fe 4 O 9 is a parallelepiped, and the parallelepiped morphology is more regular and has stronger photocatalytic activity.

[0045] In one embodiment, the iron salt is selected from iron nitrate, the bismuth salt is selected from bismuth nitrate, and the alkaline solution is selected from at least one of sodium hydroxide solution and potassium hydroxide solution.

[0046] To better and more stably synthesize Bi with a hexahedral morphology 2 Fe 4 O 9 , in one embodiment, the concentration of the alkaline solution is 6 mol / L - 8 mol / L, and the mass ratio of the iron salt, the bismuth salt to the alkaline solution is (2 - 4):(1 - 2):50.

[0047] To make the subsequent hydrothermal reaction more sufficient, in one embodiment, the preferred way to mix the iron salt, bismuth salt and alkaline solution is stirring, and the stirring time is 20 min - 40 min.

[0048] Specifically, in the step of carrying out the hydrothermal reaction after mixing the iron salt, bismuth salt and alkaline solution, the reaction temperature is 180 °C - 220 °C, and the reaction time is 12 h - 24 h.

[0049] It should be noted that, in order to better 2 Fe 4 O 9After being separated from the product, after the hydrothermal reaction step, there are also centrifugation and drying steps. Preferably, the rotation speed during centrifugation is 7000 rpm - 9000 rpm, the drying temperature is preferably 50°C - 60°C, and the drying time is preferably 12 h - 24 h.

[0050] In step S2, under the combined action of the first sacrificial agent and full-spectrum irradiation, the electrons in Bi 2 Fe 4 O 9 are consumed by the first sacrificial agent, and the holes oxidize the manganese salt into MnO x and uniformly deposit it on the surface of the crystal plane dominated by holes of the hexahedral-shaped Bi 2 Fe 4 O 9 .

[0051] Preferably, the manganese salt is selected from manganese nitrate.

[0052] In one embodiment, the solution of the first sacrificial agent is selected from sodium iodate solution.

[0053] To better deposit MnO x , in one embodiment, the mass ratio of the manganese salt to the Bi 2 Fe 4 O 9 is 0.001:100 - 1:100, and the mass ratio of the first sacrificial agent to the Bi 2 Fe 4 O 9 is 1:1 - 2:3.

[0054] In the step of mixing the Bi 2 Fe 4 O 9 , manganese salt, and the solution of the first sacrificial agent, it is preferably to add the Bi 2 Fe 4 O 9 and the manganese salt into the solution of the first sacrificial agent.

[0055] To better deposit MnO x on the surface of the crystal plane dominated by holes of the hexahedral-shaped Bi 2 Fe 4 O 9 , in one embodiment, in the step of performing full-spectrum irradiation after mixing the Bi 2 Fe 4 O 9 , manganese salt, and the solution of the first sacrificial agent, the irradiation time is 180 min - 240 min.

[0056] It should be noted that to better deposit MnOx -Bi 2 Fe 4 O 9 After the composite material is separated from the product and subjected to full-spectrum irradiation, a centrifugation step is further included. Preferably, the rotation speed during centrifugation is 7000 rpm - 9000 rpm.

[0057] In step S3, under the combined action of the second sacrificial agent and full-spectrum irradiation, the holes in Bi 2 Fe 4 O 9 are consumed, and the electrons reduce the gold precursor to nano-gold particles and uniformly deposit them on the surface of the crystal plane dominated by electrons in the hexahedral Bi 2 Fe 4 O 9 surface.

[0058] In one embodiment, the solution of the second sacrificial agent is selected from methanol solutions, preferably a methanol solution with a methanol content of 5% - 20%.

[0059] In one embodiment, the gold precursor is selected from chloroauric acid.

[0060] In order to better deposit nano-gold particles, in one embodiment, the mass ratio of the gold precursor to the MnO x -Bi 2 Fe 4 O 9 composite material is 1:1000 - 1:100, and the mass ratio of the second sacrificial agent to the MnO x -Bi 2 Fe 4 O 9 composite material is 1:10 - 1:5.

[0061] In the step of mixing the MnO x -Bi 2 Fe 4 O 9 composite material, the gold precursor, and the solution of the second sacrificial agent, it is preferred to add the MnO x -Bi 2 Fe 4 O 9 composite material and the gold precursor into the solution of the second sacrificial agent.

[0062] In order to better deposit nano-gold particles on the surface of the crystal plane dominated by electrons in the hexahedral Bi 2 Fe 4 O 9 surface, in one embodiment, the MnO x -Bi 2 Fe4 O 9 In the step of mixing the solution of the composite material, the gold precursor, and the second sacrificial agent and then performing full-spectrum irradiation, the irradiation time is 60 min - 120 min.

[0063] It should be noted that in order to better combine Bi 2 Fe 4 O 9 After the step of separating the composite photocatalyst from the product and performing full-spectrum irradiation, a centrifugation step is further included. Preferably, the rotation speed during centrifugation is 7000 rpm - 9000 rpm.

[0064] Since under full-spectrum irradiation, the selectivity of depositing MnO x is better than that of depositing nano-gold particles, depositing nano-gold particles after depositing MnO x can deposit MnO x and nano-gold particles on the surface of the crystal plane dominated by holes and the surface of the crystal plane dominated by electrons of the hexahedral Bi 2 Fe 4 O 9 respectively, to obtain a Bi 2 Fe 4 O 9 composite photocatalyst with uniform deposition, which is more conducive to the transport of photo-generated electrons.

[0065] The present invention also provides a Bi 2 Fe 4 O 9 composite photocatalyst obtained by the preparation method of the Bi 2 Fe 4 O 9 composite photocatalyst as described above. The Bi 2 Fe 4 O 9 composite photocatalyst includes hexahedral Bi 2 Fe 4 O 9 , and nano-gold particles loaded on the crystal plane surface dominated by electrons of the Bi 2 Fe 4 O 9 and MnO 2 Fe 4 O 9 particles loaded on the crystal plane surface dominated by holes of the Bi x particles.

[0066] The Bi 2 Fe 4 O 9The composite photocatalyst has a stronger electron-hole pair transfer ability, excellent photogenerated electron separation ability and excellent carrier separation efficiency, thus having excellent photocatalytic activity.

[0067] In one embodiment, the morphology of Bi 2 Fe 4 O 9 is a parallelepiped, and the parallelepiped morphology is more regular, so it has higher photocatalytic activity.

[0068] Furthermore, the present invention can use the Bi 2 Fe 4 O 9 composite photocatalyst as an antibacterial agent to prevent and control anthrax, Curvularia leaf spot of maize, Fusarium head blight of wheat, etc. Since the Bi 2 Fe 4 O 9 composite photocatalyst has excellent photocatalytic activity, it has excellent antibacterial effect when used as an antibacterial agent.

[0069] Hereinafter, the Bi 2 Fe 4 O 9 composite photocatalyst, its preparation method and application will be further described through the following specific examples.

[0070] Example 1

[0071] Mix 12.12 g of iron nitrate, 4.8507 g of bismuth nitrate and 240 g of sodium hydroxide solution with a concentration of 7 mol / L, stir for 20 min, then carry out hydrothermal reaction at 180 °C for 12 h. After the reaction, centrifuge at 7000 rpm to obtain a precipitate, and dry the precipitate at 50 °C for 12 h to obtain Bi 2 Fe 4 O 9 with a hexahedral morphology.

[0072] Mix the solution of 300 mg of the obtained Bi 2 Fe 4 O 9 , 0.015 mg of manganese nitrate and 197.9 mg of sodium iodate, irradiate with full spectrum for 180 min, then centrifuge at 7000 rpm to obtain the MnO x -Bi 2 Fe 4 O 9 composite material.

[0073] Mix 300 mg of the obtained MnO x -Bi 2 Fe 4 O9 The composite material, 1.5 mg of chloroauric acid, and 600 mL of a methanol solution with 5% methanol content were mixed and subjected to full-spectrum irradiation for 60 min. Then, centrifugation was performed at a speed of 7000 rpm to obtain Bi 2 Fe 4 O 9 composite photocatalyst.

[0074] The Bi 2 Fe 4 O 9 with a hexahedral morphology obtained in this example, x MnO 2 -Bi 4 Fe 9 O 2 composite material, and the X-ray diffraction pattern of the Bi 4 Fe 9 O Figure 1 composite photocatalyst is as shown. It can be seen that the Bi 2 Fe 4 O 9 obtained in this example 2 Fe 4 O 9 completely coincides with the scale diagram of Bi 2 Fe 4 O 9 , indicating that Bi x Fe 2 O 4 has been successfully synthesized in this example, and the deposition of nano-gold particles and MnO 9 will not affect the crystal plane of Bi

[0075] The scanning electron microscope image of the Bi 2 Fe 4 O 9 with a hexahedral morphology obtained in this example is as shown in a of Figure 2 . It shows a regular parallelepiped structure. The scanning electron microscope image of the Bi 2 Fe 4 O 9 composite photocatalyst obtained in this example is as shown in b and d of Figure 2 . Among them, nano-gold particles are deposited on the crystal plane surface dominated by electrons of Bi 2 Fe 4 O 9 , and MnO x is deposited on the crystal plane surface dominated by holes.

[0076] The transmission electron microscope image obtained in this example is as shown in Figure 3 . It can be seen that the lattice spacing of nano-gold particles is 0.236 nm, while MnO xIt presents an amorphous state.

[0077] The UV-visible reflection spectrum obtained in this example is as Figure 4 shown. It can be seen that after depositing nano-gold particles, the light absorption of Bi 2 Fe 4 O 9 in the visible light region is enhanced.

[0078] The X-ray photoelectron spectroscopy diagram obtained in this example is as Figure 5 shown. It can be seen that after depositing nano-gold particles, the binding energy of Bi (bismuth) increases, and after depositing MnO x the binding energy of Bi decreases.

[0079] The photocurrent diagram and impedance diagram obtained in this example are as Figure 6 and Figure 7 shown. It can be seen that the Bi 2 Fe 4 O 9 composite photocatalyst has the minimum impedance and the maximum photocurrent, so it has better electron-hole separation efficiency.

[0080] Example 2

[0081] 8.08 g of iron nitrate, 4.8507 g of bismuth nitrate and 240 g of sodium hydroxide solution with a concentration of 7 mol / L were mixed, stirred for 40 min, and then subjected to a hydrothermal reaction at 220 °C for 24 h. After the reaction, the precipitate was obtained by centrifugation at a speed of 9000 rpm, and the precipitate was dried at 60 °C for 24 h to obtain Bi 2 Fe 4 O 9 with a hexahedral morphology.

[0082] 300 mg of the above-obtained Bi 2 Fe 4 O 9 , 0.015 mg of manganese nitrate and 197.9 mg of sodium iodate solution were mixed, irradiated with the full spectrum for 180 min, and then centrifuged at a speed of 9000 rpm to obtain MnO x -Bi 2 Fe 4 O 9 composite material.

[0083] 300 mg of the above-obtained MnO x -Bi 2 Fe 4 O 9The composite material, 1.5 mg of chloroauric acid and 150 mL of a methanol solution with a methanol content of 20% were mixed, and then subjected to full-spectrum irradiation for 60 min. After that, centrifugation was carried out at a speed of 9000 rpm to obtain Bi 2 Fe 4 O 9 composite photocatalyst.

[0084] Example 3

[0085] 4.04 g of iron nitrate, 4.8507 g of bismuth nitrate and 240 g of a sodium hydroxide solution with a concentration of 7 mol / L were mixed. After stirring for 20 min, hydrothermal reaction was carried out at 180 °C for 12 h. After the reaction, centrifugation was carried out at a speed of 7000 rpm to obtain a precipitate, and the precipitate was dried at 50 °C for 12 h to obtain Bi with a hexahedral morphology 2 Fe 4 O 9 .

[0086] 300 mg of the above-obtained Bi 2 Fe 4 O 9 , 0.015 mg of manganese nitrate were added to a solution of 250 mg of sodium iodate and mixed. Full-spectrum irradiation was carried out for 180 min, and then centrifugation was carried out at a speed of 7000 rpm to obtain MnO x -Bi 2 Fe 4 O 9 composite material.

[0087] 300 mg of the above-obtained MnO x -Bi 2 Fe 4 O 9 composite material, 1.5 mg of chloroauric acid were added to 300 mL of a methanol solution with a methanol content of 10% and mixed. Full-spectrum irradiation was carried out for 60 min, and then centrifugation was carried out at a speed of 7000 rpm to obtain Bi 2 Fe 4 O 9 composite photocatalyst.

[0088] Example 4

[0089] 4.8 g of iron nitrate, 2.4254 g of bismuth nitrate and 120 g of a sodium hydroxide solution with a concentration of 7 mol / L were mixed. After stirring for 20 min, hydrothermal reaction was carried out at 180 °C for 12 h. After the reaction, centrifugation was carried out at a speed of 7000 rpm to obtain a precipitate, and the precipitate was dried at 50 °C for 12 h to obtain Bi with a hexahedral morphology 2 Fe 4 O 9 .

[0090] Mix the solution of 300 mg of Bi obtained above 2 Fe 4 O 9 , 0.015 mg of manganese nitrate and 197.9 mg of sodium iodate, irradiate with full spectrum for 180 min, then centrifuge at a speed of 7000 rpm to obtain MnO x -Bi 2 Fe 4 O 9 composite material.

[0091] Mix 300 mg of the MnO x -Bi 2 Fe 4 O 9 composite material, 1.5 mg of chloroauric acid and 600 mL of methanol solution with 5% methanol content, carry out full spectrum irradiation for 60 min, then centrifuge at a speed of 7000 rpm to obtain Bi 2 Fe 4 O 9 composite photocatalyst.

[0092] Example 5

[0093] Mix 9.6 g of iron nitrate, 2.4254 g of bismuth nitrate and 120 g of sodium hydroxide solution with a concentration of 6 mol / L, stir for 20 min and then carry out hydrothermal reaction at 180 °C for 12 h. After the reaction, centrifuge at a speed of 7000 rpm to obtain a precipitate, and dry the precipitate at 50 °C for 12 h to obtain Bi with a hexahedral morphology 2 Fe 4 O 9 .

[0094] Mix the solution of 300 mg of Bi obtained above 2 Fe 4 O 9 , 0.003 mg of manganese nitrate and 200 mg of sodium iodate, irradiate with full spectrum for 180 min, then centrifuge at a speed of 7000 rpm to obtain MnO x -Bi 2 Fe 4 O 9 composite material.

[0095] Mix 300 mg of the MnO x -Bi 2 Fe 4 O 9The composite material, 0.3 mg of chloroauric acid, and 600 mL of a methanol solution with 5% methanol content were mixed, irradiated with full-spectrum light for 60 min, and then centrifuged at a speed of 7000 rpm to obtain Bi 2 Fe 4 O 9 composite photocatalyst.

[0096] Example 6

[0097] 2.4 g of iron nitrate, 2.4254 g of bismuth nitrate, and 120 g of a sodium hydroxide solution with a concentration of 8 mol / L were mixed, stirred for 20 min, and then subjected to a hydrothermal reaction at 180 °C for 12 h. After the reaction, the precipitate was obtained by centrifugation at a speed of 9000 rpm, and the precipitate was dried at 60 °C for 24 h to obtain Bi with a hexahedral morphology 2 Fe 4 O 9 .

[0098] 300 mg of the obtained Bi 2 Fe 4 O 9 , 3 mg of manganese nitrate, and a solution of 300 mg of sodium iodate were mixed, irradiated with full-spectrum light for 240 min, and then centrifuged at a speed of 9000 rpm to obtain MnO x -Bi 2 Fe 4 O 9 composite material.

[0099] 300 mg of the obtained MnO x -Bi 2 Fe 4 O 9 composite material, 3 mg of chloroauric acid, and 300 mL of a methanol solution with 20% methanol content were mixed, irradiated with full-spectrum light for 120 min, and then centrifuged at a speed of 7000 rpm to obtain Bi 2 Fe 4 O 9 composite photocatalyst.

[0100] Comparative Example 1

[0101] 12.12 g of iron nitrate, 4.8507 g of bismuth nitrate, and 240 g of a sodium hydroxide solution with a concentration of 7 mol / L were mixed, stirred for 20 min, and then subjected to a hydrothermal reaction at 180 °C for 12 h. After the reaction, the precipitate was obtained by centrifugation at a speed of 7000 rpm, and the precipitate was dried at 50 °C for 12 h to obtain Bi with a hexahedral morphology 2 Fe 4 O 9 .

[0102] Mix 300 mg of the above-obtained Bi 2 Fe 4 O 9 with 1.5 mg of chloroauric acid and 600 mL of a methanol solution with a methanol content of 5%, perform full-spectrum irradiation for 60 min, and then centrifuge at a speed of 7000 rpm to obtain AuNPs-Bi 2 Fe 4 O 9 composite material.

[0103] Comparative Example 2

[0104] Mix 12.12 g of iron nitrate, 4.8507 g of bismuth nitrate and 240 g of a sodium hydroxide solution with a concentration of 7 mol / L, stir for 20 min, then carry out a hydrothermal reaction at 180 °C for 12 h. After the reaction, centrifuge at a speed of 7000 rpm to obtain a precipitate, and dry the precipitate at 50 °C for 12 h to obtain Bi 2 Fe 4 O 9 with a hexahedral morphology.

[0105] Mix 300 mg of the above-obtained Bi 2 Fe 4 O 9 with a solution of 0.015 mg of manganese nitrate and 197.9 mg of sodium iodate, irradiate with full spectrum for 180 min, and then centrifuge at a speed of 7000 rpm to obtain MnO x -Bi 2 Fe 4 O 9 composite material.

[0106] Comparative Example 3

[0107] Mix 12.12 g of iron nitrate, 4.8507 g of bismuth nitrate and 240 g of a sodium hydroxide solution with a concentration of 7 mol / L, stir for 20 min, then carry out a hydrothermal reaction at 180 °C for 12 h. After the reaction, centrifuge at a speed of 7000 rpm to obtain a precipitate, and dry the precipitate at 50 °C for 12 h to obtain Bi 2 Fe 4 O 9 with a hexahedral morphology.

[0108] Mix 300 mg of the above-obtained Bi 2 Fe 4 O 9 with 1.5 mg of chloroauric acid and 600 mL of a methanol solution with a methanol content of 5%, perform full-spectrum irradiation for 60 min, and then centrifuge at a speed of 7000 rpm to obtain AuNPs-Bi2 Fe 4 O 9 Composite material.

[0109] Mix 300 mg of the above-obtained AuNPs-Bi 2 Fe 4 O 9 composite material, 0.015 mg of manganese nitrate and 197.9 mg of sodium iodate solution, irradiate with full spectrum for 180 min, and then centrifuge at a speed of 7000 rpm to obtain Bi 2 Fe 4 O 9 Composite photocatalyst.

[0110] Test Example 1

[0111] Perform antifungal experiments on the Bi 2 Fe 4 O 9 、Bi 2 Fe 4 O 9 composite photocatalyst, the MnO x -Bi 2 Fe 4 O 9 composite material obtained in Comparative Example 1, and the AuNPs-Bi 2 Fe 4 O 9 composite material obtained in Comparative Example 2. The specific process is as follows:

[0112] Disperse the Bi 2 Fe 4 O 9 、Bi 2 Fe 4 O 9 composite photocatalyst, MnO x -Bi 2 Fe 4 O 9 composite material, and AuNPs-Bi 2 Fe 4 O 9 composite materials as additives in PDA (Potato Dextrose Agar) medium respectively, so that the concentration of the additive is 0.5 mg / mL.

[0113] After that, in the above-mentioned medium added with Bi 2 Fe 4 O 9 、Bi 2 Fe 4 O 9 composite photocatalyst, MnO x -Bi2 Fe 4 O 9 Composite material, AuNPs-Bi 2 Fe 4 O 9 The Curvularia lunata was inoculated into the PDA medium of the composite material, and irradiated with a xenon lamp with a spectrum of 400 nm and a power of 300 w. The irradiation times were 0 min, 15 min, 30 min, 45 min, and 60 min respectively. After the irradiation, the medium was placed in an incubator for cultivation at a temperature of 28 °C, and the mycelial growth was observed after 3 days of cultivation. The results are as Figure 8 shown. It can be seen that after 3 days of cultivation, in the medium with additives, the non-irradiated medium was covered with mycelia, while after irradiation, the growth of mycelia could be inhibited, and the addition of Bi 2 Fe 4 O 9 The PDA medium of the composite photocatalyst had a better effect than other media.

[0114] The photocatalysts obtained in Examples 1-6 and the composites obtained in Comparative Examples 1-3 were used as additives respectively, and the antifungal experiments were carried out in the above manner. After 3 days of growth, their antibacterial rates were tested. The test method was as follows, and the test results are shown in Table 1:

[0115] Antibacterial rate (%) = (colony diameter of the control group - colony diameter of the treatment group) / (colony diameter of the control group - diameter of the bacterial cake) × 100%. Where the control group was the PDA medium without additives, and the treatment groups were the PDA media with the photocatalysts obtained in Examples 1-6 and the composites obtained in Comparative Examples 1-3 respectively.

[0116] Table 1

[0117] Bacteriostatic rate (%) Example 1 96.2 Example 2 100 Example 3 95.3 Example 4 96.4 Example 5 97.5 Example 6 92.5 Comparative Example 1 49.5 Comparative Example 2 52.7 Comparative Example 3 91.4

[0118] As can be seen from Table 1, the antibacterial rate of the Bi 2 Fe 4 O 9 composite photocatalyst of the present invention can reach 100%, and according to Example 1 and Comparative Example 3, it can be seen that the antibacterial rate of the photocatalyst obtained by depositing nano-gold particles after depositing MnO x is higher. Therefore, the Bi 2 Fe 4 O 9 composite photocatalyst of the present invention has an efficient antibacterial effect.

[0119] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0120] The above-described embodiments merely represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A method for preparing a Bi 2 Fe 4 O 9 composite photocatalyst, It is characterized in that It includes the following steps: Mix an iron salt, a bismuth salt, and an alkaline solution and then carry out a hydrothermal reaction to obtain Bi with a hexahedral morphology 2 Fe 4 O 9 ; Mix the solution of the Bi 2 Fe 4 O 9 , manganese salt, and the first sacrificial agent, and then perform full-spectrum irradiation to deposit MnO x particles on the surface of the crystal plane dominated by holes of the Bi 2 Fe 4 O 9 to obtain a MnO x -Bi 2 Fe 4 O 9 composite material; Mix the solution of the MnO x -Bi 2 Fe 4 O 9 composite material, the gold precursor, and the second sacrificial agent, and then perform full-spectrum irradiation to deposit gold nanoparticles on the surface of the Bi 2 Fe 4 O 9 crystal plane dominated by electrons to obtain the Bi 2 Fe 4 O 9 composite photocatalyst.

2. The preparation method of the Bi 2 Fe 4 O 9 composite photocatalyst It is characterized in that The Bi 2 Fe 4 O 9 has a parallelepiped morphology.

3. The preparation method of the Bi 2 Fe 4 O 9 composite photocatalyst according to claim 1 It is characterized in that The concentration of the alkaline solution is 6 mol / L - 8 mol / L, and the mass ratio of the iron salt, the bismuth salt to the alkaline solution is (2 - 4):(1 - 2):

50.

4. The preparation method of the Bi 2 Fe 4 O 9 composite photocatalyst It is characterized in that The mass ratio of the manganese salt to the Bi 2 Fe 4 O 9 is 0.001:100 - 1:100; and / or, the mass ratio of the first sacrificial agent to Bi 2 Fe 4 O 9 is 1:1 - 2:

3.

5. The preparation method of the Bi 2 Fe 4 O 9 composite photocatalyst according to claim 1 It is characterized in that The gold precursor and the MnO x -Bi 2 Fe 4 O 9 mass ratio of the composite material is 1:1000 - 1:100; And / or, the mass ratio of the second sacrificial agent to the MnO x -Bi 2 Fe 4 O 9 composite material is 1:10 - 1:

5.

6. The preparation method of the Bi 2 Fe 4 O 9 composite photocatalyst, It is characterized in that In the step of carrying out hydrothermal reaction after mixing the iron salt, the bismuth salt and the alkaline solution, the reaction temperature is 180°C - 220°C, and the reaction time is 12 h - 24 h; and / or, mixing the solution of the Bi 2 Fe 4 O 9 , manganese salt and the first sacrificial agent and performing a full-spectrum irradiation step, wherein the irradiation time is 180 min - 240 min; and / or, mixing the solution of the MnO x -Bi 2 Fe 4 O 9 composite material, gold precursor, and second sacrificial agent, and performing a full-spectrum irradiation step, wherein the irradiation time is 60 min to 120 min.

7. The preparation method of the Bi 2 Fe 4 O 9 composite photocatalyst according to Claim 1 It is characterized in that The alkaline solution is selected from at least one of sodium hydroxide solution and potassium hydroxide solution; And / or, the iron salt is selected from iron nitrate; And / or, the bismuth salt is selected from bismuth nitrate; And / or, the manganese salt is selected from manganese nitrate; And / or, the solution of the first sacrificial agent is selected from sodium iodate solution; And / or, the solution of the second sacrificial agent is selected from methanol solution; And / or, the gold precursor is selected from chloroauric acid.

8. A Bi 2 Fe 4 O 9 composite photocatalyst obtained by the preparation method of the Bi 2 Fe 4 O 9 composite photocatalyst, It is characterized in that The Bi 2 Fe 4 O 9 composite photocatalyst includes Bi 2 Fe 4 O 9 in a hexahedral morphology, as well as nano-gold particles loaded on the surface of the crystal plane dominated by electrons of the Bi 2 Fe 4 O 9 and MnO 2 Fe 4 O 9 particles loaded on the surface of the crystal plane dominated by holes of the Bi x particles.

9. The Bi 2 Fe 4 O 9 composite photocatalyst according to claim 8 It is characterized in that The Bi 2 Fe 4 O 9 has a parallelepiped morphology.

10. A Bi as claimed in claim 8 or 9 2 Fe 4 O 9 composite photocatalyst is used as an antibacterial agent.

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