Bismuth oxybromide-synergistic bismuth metal-modified amorphous bismuth oxide catalyst and its preparation method

Abstract

This invention belongs to the field of photocatalyst technology, specifically relating to a bismuth oxybromide-co-modified amorphous bismuth oxide catalyst and its preparation method. The preparation method of the bismuth oxybromide-co-modified amorphous bismuth oxide catalyst includes the following steps: dissolving bismuth nitrate pentahydrate in nitric acid solution, adding ethylene glycol and stirring until homogeneous; subjecting the resulting suspension to a hydrothermal reaction to obtain a bismuth-modified amorphous bismuth oxide material; dissolving the bismuth-modified amorphous bismuth oxide material in deionized water, adding saturated sodium bromide solution and stirring until homogeneous; subjecting the resulting suspension to a hydrothermal reaction to obtain the bismuth oxybromide-co-modified amorphous bismuth oxide catalyst. The bismuth oxybromide-co-modified amorphous bismuth oxide catalyst prepared by this invention has a ternary heterostructure, increased specific surface area, high visible light utilization, improved separation of photogenerated charge (chlorine), and excellent photocatalytic CO2 reduction ability.

Description

Technical Field

[0001] This invention belongs to the field of photocatalyst technology, specifically relating to a bismuth oxybromide synergistically modified amorphous bismuth oxide catalyst and its preparation method. Background Technology

[0002] Industrial development has led to the continuous depletion of the Earth's fossil fuel reserves. The burning of large quantities of non-renewable resources such as coal and oil has disrupted the balance of CO2 in the atmosphere, causing environmental problems such as global warming and seriously harming the natural ecosystem. Photocatalytic CO2 reduction technology, by drawing inspiration from plant photosynthesis, not only consumes excess CO2 in the atmosphere but also converts it into usable hydrocarbon fuels, achieving the dual benefits of energy conversion and environmental protection.

[0003] Amorphous bismuth oxide possesses advantages such as being green, non-toxic, and chemically stable. Its suitable band gap provides excellent photoresponse, and its simple preparation conditions make it suitable for large-scale production. However, the irregular atomic arrangement within amorphous bismuth oxide results in numerous bulk defects, where charge carriers easily recombine, severely impacting its photocatalytic activity. The main method to improve the performance of amorphous materials is to increase their crystallinity through high temperature and pressure, but these methods are costly and resource-intensive. It has been reported that constructing heterojunctions can effectively separate charge carriers within the material, extending the catalyst's lifespan. Currently, reports on the construction of heterojunctions from amorphous bismuth oxide are scarce, indicating a vast potential for research and development. Summary of the Invention

[0004] The technical problem to be solved by this invention is to overcome the disadvantage of low carrier separation efficiency of amorphous bismuth oxide itself, and to provide a bismuth oxybromine synergistic bismuth metal-modified amorphous bismuth oxide catalyst with a ternary heterostructure, increased specific surface area, high visible light utilization, improved separation of photogenerated charge chlorine, and excellent photocatalytic CO2 reduction ability. This invention also provides its preparation method, which is simple and easy to implement.

[0005] The preparation method of the bismuth oxybromide-co-modified amorphous bismuth oxide catalyst according to the present invention includes the following steps:

[0006] (1) Preparation of bismuth metal-modified amorphous bismuth oxide material: Bismuth nitrate pentahydrate was dissolved in nitric acid solution, and then ethylene glycol was added and stirred evenly. The resulting suspension was subjected to hydrothermal reaction to obtain bismuth metal-modified amorphous bismuth oxide material.

[0007] (2) Preparation of bismuth oxybromide synergistic metal bismuth modified amorphous bismuth oxide catalyst: The metal bismuth modified amorphous bismuth oxide material was dissolved in deionized water, and then saturated sodium bromide solution was added and stirred evenly. The resulting suspension was subjected to hydrothermal reaction to obtain the bismuth oxybromide synergistic metal bismuth modified amorphous bismuth oxide catalyst.

[0008] In step (1) of this invention, the mass of bismuth nitrate pentahydrate is 0.182 g, the concentration of nitric acid solution is 1 mol / L, the amount used is 5 mL, and the amount of ethylene glycol used is 25 mL.

[0009] In step (1) of this invention, the obtained suspension is placed in a stainless steel autoclave with a polytetrafluoroethylene liner and placed in an oven for hydrothermal reaction. The hydrothermal reaction temperature is 120-180℃ and the time is 1-12h.

[0010] In step (1) of this invention, after the hydrothermal reaction is completed, the obtained product is collected by centrifugation, then washed with deionized water and anhydrous ethanol in sequence, and vacuum dried to obtain amorphous bismuth oxide powder modified with metallic bismuth.

[0011] In step (2) of this invention, the temperature of the saturated sodium bromide solution is 15-35℃.

[0012] In step (2) of this invention, the mass of the amorphous bismuth oxide powder modified with metallic bismuth is 0.0418 g, the amount of deionized water is 25 mL, and the amounts of saturated sodium bromide solution are 0.03 mL, 0.05 mL, 0.07 mL, 0.10 mL, 0.15 mL and 1 mL, respectively.

[0013] In step (2) of this invention, the obtained suspension is placed in a stainless steel autoclave with a polytetrafluoroethylene liner and placed in an oven for hydrothermal reaction. The hydrothermal reaction temperature is 140-180℃ and the time is 1-6h.

[0014] In step (2) of this invention, after the hydrothermal reaction is completed, the obtained product is collected by centrifugation, then washed with deionized water and anhydrous ethanol in sequence, and dried under vacuum to obtain amorphous bismuth oxide catalyst modified with bismuth bromooxy and metallic bismuth.

[0015] The present invention also provides a bismuth oxybromide-co-modified amorphous bismuth oxide catalyst with metallic bismuth, which is prepared by the above preparation method.

[0016] The catalyst is a ternary heterostructure in which bismuth oxybromine has an open tetragonal crystal structure and suitable band positions, and possesses excellent physical properties such as high conductivity, high refractive index, and high specific surface area. When it forms a heterostructure with amorphous bismuth oxide, it can improve the separation rate of photogenerated charges.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] (1) This invention provides a method for preparing amorphous bismuth oxide ternary composite material. Compared with increasing the crystallinity of amorphous bismuth oxide by high temperature and high pressure, this method has the advantages of strong controllability, simple operation, low cost, and clean and environmentally friendly.

[0019] (2) The amorphous bismuth oxide composite material prepared in this invention exhibits excellent CO2 to CO conversion performance under simulated sunlight. This is mainly attributed to the fact that metallic bismuth can induce surface plasmon resonance (SPR) under light, generating hot electrons to increase the surface charge density of the material and promote the absorption of visible light; the modification of bismuth oxybromine increases the specific surface area of ​​the material and exposes more active sites, which is beneficial for CO2 adsorption; the ternary heterostructure can improve the utilization rate of photogenerated charge. Attached Figure Description

[0020] Figure 1 XRD patterns of the catalysts prepared in Example 1 and Comparative Examples 1-6;

[0021] Figure 2 TEM and HRTEM images of 30% BiOBr / Bi-BiO(A) prepared in Example 1;

[0022] Figure 3 BET plots of the catalysts prepared in Example 1, Comparative Example 1, and Comparative Example 6;

[0023] Figure 4 UV-vis images of the catalysts prepared in Example 1, Comparative Example 1, and Comparative Example 6;

[0024] Figure 5 Photocurrent diagrams of the catalysts prepared in Example 1, Comparative Example 1, and Comparative Example 6;

[0025] Figure 6 The photocatalytic CO2 reduction activity diagrams are shown for the catalysts prepared in Example 1 and Comparative Examples 1-6. Detailed Implementation

[0026] The present invention will be described in detail below with reference to specific embodiments.

[0027] Unless otherwise specified, the raw materials used in the embodiments are all commercially available conventional raw materials; unless otherwise specified, the process methods used in the embodiments are all conventional methods in the art.

[0028] Photocatalytic CO2 reduction test procedure: The activity of the catalyst was tested using a Labsolar-6A closed gas system. In each test, 30 mg of catalyst powder was poured into a 300 mL Pyrex reactor, and then 50 mL of deionized water was added to dissolve it. The external circulating water was turned on to maintain the reaction temperature at about 5°C. Then, the entire system was evacuated, and CO2 was introduced to bring the internal pressure of the system to about 75 kPa. Under irradiation with a 300 W xenon lamp (PLS-SXE300, Pyrex), the suspension was kept under magnetic stirring, and the produced gas was analyzed using a gas chromatograph (GC2002, Shanghai Kechuang).

[0029] Example 1

[0030] The steps for preparing amorphous bismuth oxide catalysts modified with bismuth metal bromine synergistically are as follows:

[0031] (1) Preparation of bismuth metal-modified amorphous bismuth oxide materials:

[0032] 0.182 g of bismuth nitrate pentahydrate was dissolved in 5 mL of 1 mol / L nitric acid solution, and then 25 mL of ethylene glycol was added and stirred until homogeneous. The resulting suspension was placed in a stainless steel autoclave with a polytetrafluoroethylene liner, placed in an oven, and kept at 150 °C for 3 h. The product was collected by centrifugation, washed successively with deionized water and anhydrous ethanol, and dried under vacuum to obtain amorphous bismuth oxide powder modified with metallic bismuth, which was named Bi-BiO(A).

[0033] (2) Preparation of bismuth oxybromide-assisted bismuth metal-modified amorphous bismuth oxide catalyst:

[0034] 0.0418 g of Bi-BiO(A) powder was dissolved in 25 mL of deionized water, and 0.07 mL of saturated sodium bromide solution was added dropwise with stirring. The resulting suspension was placed in a stainless steel autoclave with a polytetrafluoroethylene liner and then placed in an oven at 160 °C for 3 h. The product was collected by centrifugation, washed successively with deionized water and anhydrous ethanol, and then vacuum dried to obtain an amorphous bismuth oxide material modified with bismuth oxybromide and metallic bismuth. This material was named 30%BiOBr / Bi-BiO(A), with the percentage determined by the proportion of Br in the sample as shown in XPS analysis. Its catalytic reaction rate for the conversion of CO2 to CO was 123.6 μmol·g⁻¹. -1 ·h -1 .

[0035] Example 2

[0036] The steps for preparing amorphous bismuth oxide catalysts modified with bismuth metal bromine synergistically are as follows:

[0037] (1) Preparation of bismuth metal-modified amorphous bismuth oxide materials:

[0038] 0.182 g of bismuth nitrate pentahydrate was dissolved in 5 mL of 1 mol / L nitric acid solution, and then 25 mL of ethylene glycol was added and stirred until homogeneous. The resulting suspension was placed in a stainless steel autoclave with a polytetrafluoroethylene liner, placed in an oven, and kept at 150 °C for 3 h. The product was collected by centrifugation, washed successively with deionized water and anhydrous ethanol, and dried under vacuum to obtain amorphous bismuth oxide powder modified with metallic bismuth, which was named Bi-BiO(A).

[0039] (2) Preparation of bismuth oxybromide-assisted bismuth metal-modified amorphous bismuth oxide catalyst:

[0040] 0.0418 g of Bi-BiO(A) powder was dissolved in 25 mL of deionized water, and 0.06 mL of saturated sodium bromide solution was added dropwise with stirring until homogeneous. The resulting suspension was placed in a stainless steel autoclave with a polytetrafluoroethylene liner and placed in an oven. The autoclave was maintained at 160 °C for 3 h. The resulting product was collected by centrifugation, washed successively with deionized water and anhydrous ethanol, and then vacuum dried to obtain an amorphous bismuth oxide material modified with bismuth oxybromide and metallic bismuth. This material was named 25%BiOBr / Bi-BiO(A). Its catalytic reaction rate for the conversion of CO2 to CO was 112.3 μmol·g⁻¹. -1 ·h -1 .

[0041] Example 3

[0042] The steps for preparing amorphous bismuth oxide catalysts modified with bismuth metal bromine synergistically are as follows:

[0043] (1) Preparation of bismuth metal-modified amorphous bismuth oxide materials:

[0044] 0.182 g of bismuth nitrate pentahydrate was dissolved in 5 mL of 1 mol / L nitric acid solution, and then 25 mL of ethylene glycol was added and stirred until homogeneous. The resulting suspension was placed in a stainless steel autoclave with a polytetrafluoroethylene liner, placed in an oven, and kept at 150 °C for 3 h. The product was collected by centrifugation, washed successively with deionized water and anhydrous ethanol, and dried under vacuum to obtain amorphous bismuth oxide powder modified with metallic bismuth, which was named Bi-BiO(A).

[0045] (2) Preparation of bismuth oxybromide-assisted bismuth metal-modified amorphous bismuth oxide catalyst:

[0046] 0.0418 g of Bi-BiO(A) powder was dissolved in 25 mL of deionized water, and 0.08 mL of saturated sodium bromide solution was added dropwise with stirring until homogeneous. The resulting suspension was placed in a stainless steel autoclave with a polytetrafluoroethylene liner and then placed in an oven at 160 °C for 3 h. The product was collected by centrifugation, washed successively with deionized water and anhydrous ethanol, and then vacuum dried to obtain an amorphous bismuth oxide material modified with bismuth oxybromide and metallic bismuth, which was named 35%BiOBr / Bi-BiO(A). Its catalytic reaction rate for the conversion of CO2 to CO was 108.5 μmol·g⁻¹. -1 ·h -1 .

[0047] Comparative Example 1

[0048] The steps for preparing bismuth-modified amorphous bismuth oxide materials are as follows:

[0049] 0.182 g of bismuth nitrate pentahydrate was dissolved in 5 mL of 1 mol / L nitric acid solution, and then 25 mL of ethylene glycol was added and stirred until homogeneous. The resulting suspension was placed in a stainless steel autoclave with a polytetrafluoroethylene liner, placed in an oven, and kept at 150 °C for 3 h. The product was collected by centrifugation, washed successively with deionized water and anhydrous ethanol, and dried under vacuum to obtain amorphous bismuth oxide powder modified with metallic bismuth, which was named Bi-BiO(A).

[0050] Comparative Example 2

[0051] The steps for preparing amorphous bismuth oxide catalysts modified with bismuth metal bromine synergistically are as follows:

[0052] (1) Preparation of bismuth metal-modified amorphous bismuth oxide materials:

[0053] 0.182 g of bismuth nitrate pentahydrate was dissolved in 5 mL of 1 mol / L nitric acid solution, and then 25 mL of ethylene glycol was added and stirred until homogeneous. The resulting suspension was placed in a stainless steel autoclave with a polytetrafluoroethylene liner, placed in an oven, and kept at 150 °C for 3 h. The product was collected by centrifugation, washed successively with deionized water and anhydrous ethanol, and dried under vacuum to obtain amorphous bismuth oxide powder modified with metallic bismuth, which was named Bi-BiO(A).

[0054] (2) Preparation of bismuth oxybromide-assisted bismuth metal-modified amorphous bismuth oxide catalyst:

[0055] 0.0418 g of Bi-BiO(A) powder was dissolved in 25 mL of deionized water, and 0.03 mL of saturated sodium bromide solution was added dropwise and stirred until homogeneous. The resulting suspension was placed in a stainless steel autoclave with a polytetrafluoroethylene liner, placed in an oven, and kept at 160 °C for 3 h. The resulting product was collected by centrifugation, washed successively with deionized water and anhydrous ethanol, and dried under vacuum to obtain an amorphous bismuth oxide material modified with bismuth oxybromide and metallic bismuth, which was named 15%BiOBr / Bi-BiO(A).

[0056] Comparative Example 3

[0057] The steps for preparing amorphous bismuth oxide catalysts modified with bismuth metal bromine synergistically are as follows:

[0058] (1) Preparation of bismuth metal-modified amorphous bismuth oxide materials:

[0059] 0.182 g of bismuth nitrate pentahydrate was dissolved in 5 mL of 1 mol / L nitric acid solution, and then 25 mL of ethylene glycol was added and stirred until homogeneous. The resulting suspension was placed in a stainless steel autoclave with a polytetrafluoroethylene liner, placed in an oven, and kept at 150 °C for 3 h. The product was collected by centrifugation, washed successively with deionized water and anhydrous ethanol, and dried under vacuum to obtain amorphous bismuth oxide powder modified with metallic bismuth, which was named Bi-BiO(A).

[0060] (2) Preparation of bismuth oxybromide-assisted bismuth metal-modified amorphous bismuth oxide catalyst:

[0061] 0.0418 g of Bi-BiO(A) powder was dissolved in 25 mL of deionized water, and 0.05 mL of saturated sodium bromide solution was added dropwise and stirred until homogeneous. The resulting suspension was placed in a stainless steel autoclave with a polytetrafluoroethylene liner, placed in an oven, and kept at 160 °C for 3 h. The resulting product was collected by centrifugation, washed successively with deionized water and anhydrous ethanol, and dried under vacuum to obtain an amorphous bismuth oxide material modified with bismuth oxybromide and metallic bismuth, which was named 20%BiOBr / Bi-BiO(A).

[0062] Comparative Example 4

[0063] The steps for preparing amorphous bismuth oxide catalysts modified with bismuth metal bromine synergistically are as follows:

[0064] (1) Preparation of bismuth metal-modified amorphous bismuth oxide materials:

[0065] 0.182 g of bismuth nitrate pentahydrate was dissolved in 5 mL of 1 mol / L nitric acid solution, and then 25 mL of ethylene glycol was added and stirred until homogeneous. The resulting suspension was placed in a stainless steel autoclave with a polytetrafluoroethylene liner, placed in an oven, and kept at 150 °C for 3 h. The product was collected by centrifugation, washed successively with deionized water and anhydrous ethanol, and dried under vacuum to obtain amorphous bismuth oxide powder modified with metallic bismuth, which was named Bi-BiO(A).

[0066] (2) Preparation of bismuth oxybromide-assisted bismuth metal-modified amorphous bismuth oxide catalyst:

[0067] 0.0418 g of Bi-BiO(A) powder was dissolved in 25 mL of deionized water, and 0.10 mL of saturated sodium bromide solution was added dropwise and stirred until homogeneous. The resulting suspension was placed in a stainless steel autoclave with a polytetrafluoroethylene liner, placed in an oven, and kept at 160 °C for 3 h. The resulting product was collected by centrifugation, washed successively with deionized water and anhydrous ethanol, and dried under vacuum to obtain an amorphous bismuth oxide material modified with bismuth oxybromide and metallic bismuth, which was named 40%BiOBr / Bi-BiO(A).

[0068] Comparative Example 5

[0069] The steps for preparing amorphous bismuth oxide catalysts modified with bismuth metal bromine synergistically are as follows:

[0070] (1) Preparation of bismuth metal-modified amorphous bismuth oxide materials:

[0071] 0.182 g of bismuth nitrate pentahydrate was dissolved in 5 mL of 1 mol / L nitric acid solution, and then 25 mL of ethylene glycol was added and stirred until homogeneous. The resulting suspension was placed in a stainless steel autoclave with a polytetrafluoroethylene liner, placed in an oven, and kept at 150 °C for 3 h. The product was collected by centrifugation, washed successively with deionized water and anhydrous ethanol, and dried under vacuum to obtain amorphous bismuth oxide powder modified with metallic bismuth, which was named Bi-BiO(A).

[0072] (2) Preparation of bismuth oxybromide-assisted bismuth metal-modified amorphous bismuth oxide catalyst:

[0073] 0.0418 g of Bi-BiO(A) powder was dissolved in 25 mL of deionized water, and 0.15 mL of saturated sodium bromide solution was added dropwise and stirred until homogeneous. The resulting suspension was placed in a stainless steel autoclave with a polytetrafluoroethylene liner, placed in an oven, and kept at 160 °C for 3 h. The resulting product was collected by centrifugation, washed successively with deionized water and anhydrous ethanol, and dried under vacuum to obtain an amorphous bismuth oxide material modified with bismuth oxybromide and metallic bismuth, which was named 60%BiOBr / Bi-BiO(A).

[0074] Comparative Example 6

[0075] The steps for preparing the bismuth oxybromide catalyst are as follows:

[0076] (1) Preparation of bismuth metal-modified amorphous bismuth oxide materials:

[0077] 0.182 g of bismuth nitrate pentahydrate was dissolved in 5 mL of 1 mol / L nitric acid solution, and then 25 mL of ethylene glycol was added and stirred until homogeneous. The resulting suspension was placed in a stainless steel autoclave with a polytetrafluoroethylene liner, placed in an oven, and kept at 150 °C for 3 h. The product was collected by centrifugation, washed successively with deionized water and anhydrous ethanol, and dried under vacuum to obtain amorphous bismuth oxide powder modified with metallic bismuth, which was named Bi-BiO(A).

[0078] (2) Preparation of bismuth oxybromide-assisted bismuth metal-modified amorphous bismuth oxide catalyst:

[0079] 0.0418 g of Bi-BiO(A) powder was dissolved in 25 mL of deionized water, and 1 mL of saturated sodium bromide solution was added dropwise and stirred until homogeneous. The resulting suspension was placed in a stainless steel autoclave with a polytetrafluoroethylene liner, placed in an oven, and kept at 160 °C for 3 h. The resulting product was collected by centrifugation, washed successively with deionized water and anhydrous ethanol, and dried under vacuum to obtain bismuth oxybromide material, which was named BiOBr.

[0080] The performance of the catalyst is compared and explained using the 30% BiOBr / Bi-BiO(A) prepared in Example 1 as an example.

[0081] (1) The catalysts prepared in Example 1 and Comparative Examples 1-6 were subjected to XRD analysis, and the results are shown in the figure. Figure 1 .

[0082] XRD analysis revealed that Bi-BiO(A) exhibited only a broad diffraction peak around 30°, indicating that the sample has a typical amorphous structure. After treatment with a certain amount of NaBr, characteristic diffraction peaks of BiOBr appeared at positions of 25.2°, 32.2°, 46.2°, and 57.1°. These characteristic diffraction peaks became increasingly prominent with increasing NaBr content, suggesting that excess NaBr can completely convert Bi-BiO(A) into BiOBr.

[0083] (2) The 30% BiOBr / Bi-BiO(A) prepared in Example 1 was analyzed by TEM and HRTEM. The results are shown in the figure. Figure 2 .

[0084] TEM analysis revealed that the 30% BiOBr / Bi-BiO(A) sample exhibited a spherical morphology with a diameter of approximately 150-200 nm, and irregular nanosheets could be observed at the edges of the spheres. In the HRTEM images of the 30% BiOBr / Bi-BiO(A), lattice fringes of metallic Bi and BiOBr were observed, respectively. Nanoparticles without surrounding lattice fringes were considered to be amorphous bismuth oxide.

[0085] (3) The catalysts prepared in Example 1, Comparative Example 1, and Comparative Example 6 were subjected to BET analysis, and the results are shown in the figure. Figure 3 .

[0086] BET analysis revealed that compared to Bi-BiO(A) (3.64m) 2 / g), the specific surface area of ​​30% BiOBr / Bi-BiO(A) is 19.55m². 2 The surface roughness of Bi-BiO(A) is significantly increased by / g), which is because BiOBr nanosheets can be modified on the surface of Bi-BiO(A) to increase the surface roughness, thereby effectively increasing the specific surface area of ​​the material.

[0087] (4) The catalysts prepared in Example 1, Comparative Example 1, and Comparative Example 6 were subjected to UV-vis analysis, and the results are shown in the figure. Figure 4 .

[0088] UV-vis analysis revealed that all samples exhibited strong light response in the ultraviolet region, but Bi-BiO(A) and 30% BiOBr / Bi-BiO(A) showed stronger absorption in visible light. This is attributed to the surface plasmon resonance effect of metallic Bi, which effectively enhances the absorbance of the composite material and excites more charge carriers.

[0089] (5) The catalysts prepared in Example 1, Comparative Example 1, and Comparative Example 6 were subjected to photocurrent analysis, and the results are shown in the figure. Figure 5 .

[0090] Photocurrent analysis revealed that 30% BiOBr / Bi-BiO(A) exhibited the highest photocurrent density, indicating that more photogenerated electrons participated in the reduction reaction on the surface of BiOBr / Bi-BiO(A), suggesting that constructing heterostructures can better separate and transfer photogenerated charges.

[0091] (6) The catalysts prepared in Example 1 and Comparative Examples 1-6 were subjected to photocatalytic reduction of CO2 in a pure water system under simulated sunlight. The results are shown in […]. Figure 6 .

[0092] Activity analysis of photocatalytic CO2 reduction in a pure water system under simulated sunlight revealed that Bi-BiO(A), 15%, 20%, 30%, 40%, and 60% BiOBr / Bi-BiO(A), and BiOBr could selectively convert CO2 to CO, with reaction rates of 95.32, 40.21, 90.26, 123.61, 76.24, 55.05, and 31.79 μmol·g⁻¹, respectively. -1 h -1 It is evident that modifying with an appropriate amount of BiOBr can effectively enhance the photocatalytic activity of the sample. The CO evolution rate on 30% BiOBr / Bi-BiO(A) is approximately 1.30 times that of Bi-BiO(A) and 3.89 times that of BiOBr, indicating that the prepared 30% BiOBr / Bi-BiO(A) possesses excellent photocatalytic CO2 reduction performance.

[0093] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A method for preparing a bismuth oxybromide-co-modified amorphous bismuth oxide catalyst with metallic bismuth, characterized in that: Includes the following steps: (1) Preparation of bismuth metal-modified amorphous bismuth oxide material: Bismuth nitrate pentahydrate was dissolved in nitric acid solution, and then ethylene glycol was added and stirred evenly. The resulting suspension was subjected to hydrothermal reaction to obtain bismuth metal-modified amorphous bismuth oxide material; the mass of bismuth nitrate pentahydrate was 0.182 g, the concentration of nitric acid solution was 1 mol / L, the amount was 5 mL, and the amount of ethylene glycol was 25 mL. (2) Preparation of bismuth oxybromide synergistic metal bismuth modified amorphous bismuth oxide catalyst: The metal bismuth modified amorphous bismuth oxide material was dissolved in deionized water, and then saturated sodium bromide solution was added and stirred evenly. The resulting suspension was subjected to hydrothermal reaction to obtain bismuth oxybromide synergistic metal bismuth modified amorphous bismuth oxide catalyst; the mass of the metal bismuth modified amorphous bismuth oxide powder was 0.0418 g, the amount of deionized water was 25 mL, and the amount of saturated sodium bromide solution was 0.06 mL, 0.07 mL or 0.08 mL respectively.

2. The method for preparing the bismuth oxybromide-co-modified amorphous bismuth oxide catalyst according to claim 1, characterized in that: In step (1), the obtained suspension is placed in a stainless steel autoclave with a polytetrafluoroethylene liner and placed in an oven for hydrothermal reaction. The hydrothermal reaction temperature is 120-180℃ and the time is 1-12h.

3. The method for preparing the bismuth oxybromide-co-modified amorphous bismuth oxide catalyst according to claim 1, characterized in that: In step (1), after the hydrothermal reaction is completed, the product is collected by centrifugation, then washed with deionized water and anhydrous ethanol in sequence, and dried under vacuum to obtain amorphous bismuth oxide powder modified with metallic bismuth.

4. The method for preparing the bismuth oxybromide-co-modified amorphous bismuth oxide catalyst according to claim 1, characterized in that: In step (2), the temperature of the saturated sodium bromide solution is 15-35℃.

5. The method for preparing the bismuth oxybromide-co-modified amorphous bismuth oxide catalyst according to claim 1, characterized in that: In step (2), the obtained suspension is placed in a stainless steel autoclave with a polytetrafluoroethylene liner and placed in an oven for hydrothermal reaction. The hydrothermal reaction temperature is 140-180℃ and the time is 1-6 h.

6. The method for preparing the bismuth oxybromide-co-modified amorphous bismuth oxide catalyst according to claim 1, characterized in that: In step (2), after the hydrothermal reaction is completed, the obtained product is collected by centrifugation, then washed with deionized water and anhydrous ethanol in sequence, and dried under vacuum to obtain amorphous bismuth oxide catalyst modified with bismuth bromooxy and metallic bismuth.

7. A bismuth oxybromide-co-modified amorphous bismuth oxide catalyst with metallic bismuth, characterized in that: It is prepared by the preparation method according to any one of claims 1-6.

8. The application of the bismuth oxybromide synergistic metal bismuth modified amorphous bismuth oxide catalyst according to claim 7 in the photocatalytic reduction of CO2 to CO.

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