Defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst as well as preparation method and application thereof

Abstract

The invention belongs to the field of photocatalytic nano materials, and discloses a defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst as well as a preparation method and application thereof. The preparation method comprises the following steps: dissolving 1-octyl-3-methylimidazolium chloride and triton X-100 in water to obtain a microemulsion A; adding bismuth nitrate pentahydrate and lead nitrate into a nitric acid solution to obtain a solution B; dropwise adding the solution B into the microemulsion A, uniformly stirring, and adding a glyoxal aqueous solution to obtain a mixed solution; and adjusting the pH value of the mixed solution to be alkaline by using a NaOH aqueous solution, and carrying out hydrothermal reaction to obtain the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst. The prepared catalyst has good photocatalytic performance, and has good application prospects in the aspects of photocatalytic CO2 reduction and degradation of water pollutants.

Description

Technical Field

[0001] This invention belongs to the field of photocatalytic nanomaterials, specifically relating to a defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst, its preparation method, and its application. Background Technology

[0002] With the continued acceleration of global industrialization, energy depletion and the environmental problems caused by the massive discharge of industrial wastewater have become two major challenges facing human society. These problems severely restrict the green and sustainable development of the ecological economy. Against this backdrop, photocatalysis technology, with its unique advantages, is considered one of the effective means to solve the energy crisis and environmental pollution dilemma. As a green catalytic technology driven by solar energy, photocatalysis can achieve efficient conversion of chemical reactions under mild conditions. Currently, it has demonstrated irreplaceable application value and broad prospects in areas such as CO2 reduction, water pollutant degradation, and the preparation of new clean energy sources, providing a new and effective approach to promoting energy structure transformation and ecological environment governance.

[0003] Bismuth oxyhalides (BiOX; X = Cl, Br, I), as structurally simple metal oxyhalides, have attracted widespread attention in the development of novel photocatalysts due to their unique layered structure and favorable bandgap characteristics. However, further development of BiOX is limited by its inherent defects, such as the low absorption capacity of BiOCl for visible light and the rapid recombination rate of photogenerated carriers. Therefore, researchers have adopted a series of strategies to improve the photocatalytic activity of BiOX, such as constructing bismuth-based bimetallic oxyhalides. Bismuth-based bimetallic oxyhalides can enhance the photocatalytic activity of bismuth oxyhalides under visible light irradiation. Among them, the novel layered material lead bismuth oxychloride (PbBiO2Cl) has been extensively studied due to its high stability and suitable bandgap, and lead ions (Pb... 2+ ) and bismuth ions (Bi 3+ The radii of the two components are similar, and by using Bi... 3+ Replace with Pb 2+Its original crystal structure will not change significantly. Currently, PbBiO2Cl materials have been reported in photocatalytic CO2 reduction and degradation of water pollutants. For example, Bin Wang et al. prepared a porous nanosheet PbBiO2Cl photocatalyst with a Sillén structure. This catalyst exhibited good photocatalytic activity in CO2 reduction under visible light conditions. However, the preparation of this catalyst requires a hydrothermal reaction followed by calcination in a hydrogen / argon environment, making the preparation process complex, costly, and difficult to control in terms of morphology. Another example is Yekang Zheng et al., who prepared a Bi2S3 / PbBiO2Cl composite photocatalyst via a two-step hydrothermal method. This composite photocatalyst can be used to degrade RhB. However, its hydrothermal time is as long as 36 hours, significantly extending the production cycle, which is not conducive to efficient industrial production and has limited applications. Improving the photogenerated carrier separation efficiency of PbBiO2Cl materials through defect construction coupled with morphology control is key to enhancing the photocatalytic performance of PbBiO2Cl. Summary of the Invention

[0004] The first technical problem to be solved by the present invention is to address the shortcomings of existing technologies, such as the complex preparation process of PbBiO2Cl photocatalysts, high economic cost, and difficulty in controlling catalyst morphology, and to provide a simple and mild method for preparing defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalysts.

[0005] The second technical problem to be solved by the present invention is to provide the application of the above-mentioned catalyst in photocatalytic CO2 reduction and degradation of water pollutants.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing a defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst includes the following steps:

[0008] (1) Dissolve 1-octyl-3-methylimidazolium chloride (OmimCl) and Triton X-100 in water and stir until homogeneous to obtain microemulsion A;

[0009] (2) Add bismuth nitrate and lead nitrate to the nitric acid solution, stir well, and you will get solution B;

[0010] (3) Add the solution B to the microemulsion A, stir until homogeneous, add glyoxal aqueous solution, and continue stirring until homogeneous to obtain a mixed solution;

[0011] (4) After adjusting the pH of the mixed solution to alkaline using NaOH aqueous solution, a hydrothermal reaction is carried out. After the reaction is completed, the solution is centrifuged, washed and dried to obtain the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst.

[0012] In step (1), the ratio of 1-octyl-3-methylimidazolium chloride, Triton X-100 and water is 1~2 mmol:0.2~0.4 g:25-50 mL (preferably 1 mmol:0.2 g:25 mL); the water is deionized water.

[0013] In step (2), the bismuth nitrate is bismuth nitrate pentahydrate; the ratio of the amount of bismuth nitrate, lead nitrate and nitric acid solution is 1~2 mmol:1~2 mmol:5~10 mL (preferably 1 mmol:1 mmol:5 mL); the concentration of the nitric acid solution is 0.5~1.5 mol / L (preferably 1 mol / L).

[0014] In step (3), the volume ratio of the solution B, the microemulsion A and the glyoxal aqueous solution is 1:5:0.12~0.05 (preferably 1:5:0.12); the mass fraction of the glyoxal aqueous solution is 30%~50% (preferably 40%).

[0015] In step (4), the concentration of the NaOH aqueous solution is 1.5~2.5 mol / L (preferably 2 mol / L); the alkalinity has a pH value of 9~11 (preferably 10).

[0016] In step (4), the temperature of the hydrothermal reaction is 110~150℃ (preferably 120℃), the reaction time is 4~8 h (preferably 6 h), and the reaction pressure is 2.0~3.0 MPa (preferably 2.0 MPa).

[0017] In step (4), the washing is performed using deionized water and anhydrous ethanol respectively; the drying is performed at a temperature of 50~70 ℃ (preferably 60 ℃) and for a time of 6~10 h (preferably 8 h).

[0018] The defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst prepared by the above method is also within the scope of protection of this invention.

[0019] The defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst has a concave bowl-shaped structure and a particle size of 0.5~1μm.

[0020] The application of the aforementioned defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst in the photocatalytic reduction of CO2 to CO is within the scope of protection of this invention.

[0021] The application of the aforementioned defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst in the degradation of water pollutants is also within the scope of protection of this invention; preferably, the water pollutant is an organic pollutant; more preferably, the organic pollutant is a colored fluorescent dye; most preferably, the organic pollutant is Rhodamine B.

[0022] Compared with the prior art, the present invention has the following significant advantages:

[0023] (1) The present invention uses a one-step hydrothermal method to prepare a defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst. The preparation process is simple and easy to carry out, and the preparation process is relatively short, making it suitable for mass production.

[0024] (2) In the preparation of defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst, the present invention uses glyoxal as a reducing agent to induce the formation of oxygen vacancy defects in PbBiO2Cl. Compared with other oxygen vacancy construction methods such as calcination, the glyoxal reduction method has mild reaction conditions, is easy to operate, and has high efficiency. Triton X-100 is used as a surfactant. Triton X-100 has extremely low cost, is not easily volatile, has stable properties, and low toxicity. It plays the role of a stabilizer in the aqueous microemulsion system and is easy to control the morphology.

[0025] (3) The defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst prepared in this invention has a unique ultrathin hollow bowl-shaped structure that can significantly reduce carrier diffusion resistance and effectively suppress electron-hole pair recombination. Simultaneously, the abundant oxygen vacancy defects introduced on the surface of this structure can serve as electron enrichment centers, further promoting the effective separation of photogenerated carriers. Under visible light irradiation, the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst exhibits a CO reduction rate of 28.3 μmol g / L for CO. -1 h -1 It is a traditional PbBiO2Cl nanosheet (1.7 μmol g) -1 h -1 The degradation efficiency of PbBiO2Cl nanosheets (9.2%) is 16.6 times that of PbBiO2Cl nanosheets (9.2%). At the same time, the degradation efficiency of Rhodamine B, a colored pollutant in water, is 96.2%, which is 10.5 times that of PbBiO2Cl nanosheets (9.2%).

[0026] (4) The defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst prepared by the present invention can not only achieve efficient CO2 reduction, but also has excellent pollutant degradation performance, providing new ideas for the design of new photocatalysts, carbon resource recycling and water pollution control. Attached Figure Description

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0028] Figure 1 In Figure a, a is a TEM image of the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst prepared in Example 1; and in Figure b, a TEM image of the PbBiO2Cl nanosheet photocatalyst prepared in Example 1.

[0029] Figure 2 Transient photocurrent diagrams of the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst and the PbBiO2Cl nanosheet photocatalyst prepared in Example 1.

[0030] Figure 3 The electron paramagnetic resonance spectrum of the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst prepared in Example 1.

[0031] Figure 4 The photocatalytic CO2 reduction activity diagrams are shown for the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst and the PbBiO2Cl nanosheet photocatalyst prepared in Example 1.

[0032] Figure 5 The image shows the photocatalytic activity of the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst and the PbBiO2Cl nanosheet photocatalyst prepared in Example 1 for the degradation of Rhodamine B.

[0033] Figure 6 In Figure a, the photocatalytic CO2 reduction cycle activity diagram of the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst prepared in Example 1 is shown; in Figure b, the photocatalytic degradation cycle activity diagram of the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst prepared in Example 1 is shown.

[0034] Figure 7 This is a standard curve of CO peak area versus CO production. Detailed Implementation

[0035] The present invention will be further described below with reference to specific embodiments and accompanying drawings, and the scope of protection of the present invention is not limited to the following embodiments.

[0036] Example 1

[0037] (1) Dissolve 1 mmol of OmimCl and 0.2 g of Triton X-100 in 25 ml of deionized water and stir for 60 min to form microemulsion A.

[0038] (2) Add 1 mmol of Bi(NO3)3•5H2O and 1 mmol of Pb(NO3)2 to 5 ml of 1mol / L nitric acid solution in sequence, stir for 90 min to form a homogeneous solution B.

[0039] (3) Add the homogeneous solution B dropwise to the microemulsion A, stir evenly (stir for 25 min), add 0.6 ml of 40% v / v glyoxal aqueous solution, and continue stirring for 20 min to obtain a mixed solution.

[0040] (4) Adjust the pH of the mixed solution to 10 with 2 mol / L NaOH aqueous solution, stir for 30 min, transfer the mixed solution to a high-pressure reactor for hydrothermal reaction, react for 6 h under the conditions of 2.0 MPa pressure and 120 ℃ temperature, cool to room temperature after the reaction is completed, take the solid after centrifugation, wash with deionized water and anhydrous ethanol respectively, and dry at 60 ℃ for 8 h to obtain defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst.

[0041] The preparation steps of the PbBiO2Cl nanosheet photocatalyst are as follows: 1 mmol of OmimCl, 1 mmol of Bi(NO3)3•5H2O, and 1 mmol of Pb(NO3)2 were dissolved in 25 ml of deionized water and stirred for 30 min to form a homogeneous solution. Under continuous stirring, the pH of the solution was adjusted to 10 with 2 mol / L NaOH. The mixed solution was transferred to a high-pressure reactor and reacted at 160 ℃ for 6 h. After the reaction, the solution was cooled to room temperature, centrifuged, and the solid was collected. The solid was washed with deionized water and anhydrous ethanol, respectively, and dried to obtain the PbBiO2Cl nanosheet photocatalyst.

[0042] Figure 1 Image a is a TEM image of the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst prepared in Example 1; image b is a TEM image of the PbBiO2Cl nanosheet photocatalyst prepared in Example 1. From the images, it can be observed that the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst has a uniform concave bowl-shaped structure with a particle size of 0.5~1μm; the PbBiO2Cl nanosheet photocatalyst has a rectangular sheet-like structure with flat edges with a particle size of 0.1~0.5μm.

[0043] Figure 2 In Figure a, the transient photocurrent of the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst prepared in Example 1 is shown, and in Figure b, the transient photocurrent of the PbBiO2Cl nanosheet photocatalyst prepared in Example 1 is shown. As can be seen from the figures, the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst exhibits a higher current value than the PbBiO2Cl nanosheet photocatalyst, indicating that the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst has a higher photogenerated carrier separation efficiency than the PbBiO2Cl nanosheet photocatalyst.

[0044] Figure 3The image shows the electron paramagnetic resonance (EPR) spectrum of the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst prepared in Example 1. As can be seen from the figure, the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst has a strong EPR signal, which is attributed to electrons trapped on oxygen vacancies. This indicates that there is an oxygen defect structure on the surface of the prepared defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst, which is beneficial to promoting the effective separation of photogenerated carriers.

[0045] Example 2

[0046] (1) Dissolve 1.2 mmol of OmimCl and 0.25 g of Triton X-100 in 30 ml of deionized water and stir for 70 min to form microemulsion A.

[0047] (2) Add 1.2 mmol of Bi(NO3)3•5H2O and 1.2 mmol of Pb(NO3)2 to 6 ml of 1mol / L nitric acid solution and stir for 100 min to form a homogeneous solution B.

[0048] (3) Add the homogeneous solution B dropwise to the microemulsion A, stir until homogeneous (stir for 30 min), add 0.8 ml of 40% v / v glyoxal aqueous solution, and continue stirring for 25 min to obtain a mixed solution.

[0049] (4) Adjust the pH of the mixed solution to 10.5 with 2 mol / L NaOH aqueous solution, stir for 35 min, transfer the mixed solution to a high-pressure reactor for hydrothermal reaction, react for 4 h at a pressure of 2.8 MPa and a temperature of 125 ℃, cool to room temperature after the reaction, centrifuge and take the solid, wash with deionized water and anhydrous ethanol respectively, and dry at 70 ℃ for 6 h to obtain defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst.

[0050] Example 3

[0051] (1) Dissolve 1.5 mmol of OmimCl and 0.3 g of Triton X-100 in 40 ml of deionized water and stir for 80 min to form microemulsion A.

[0052] (2) Add 1.5 mmol of Bi(NO3)3•5H2O and 1.5 mmol of Pb(NO3)2 to 8 ml of 1mol / L nitric acid solution and stir for 110 min to form a homogeneous solution B.

[0053] (3) Add the homogeneous solution B dropwise to the microemulsion A, stir evenly (stir for 40 min), add 0.7 ml of 40% v / v glyoxal aqueous solution, and continue stirring for 30 min to obtain a mixed solution.

[0054] (4) Adjust the pH of the mixed solution to 9.5 with 2 mol / L NaOH aqueous solution, stir for 40 min, transfer the mixed solution to a high-pressure reactor for hydrothermal reaction, react for 5 h at a pressure of 2.5 MPa and a temperature of 130 ℃, cool to room temperature after the reaction, centrifuge and take the solid, wash with deionized water and anhydrous ethanol respectively, and dry at 50 ℃ for 10 h to obtain defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst.

[0055] Example 4

[0056] (1) Dissolve 1.7 mmol of OmimCl and 0.35 g of Triton X-100 in 45 ml of deionized water and stir for 100 min to form microemulsion A.

[0057] (2) Add 1.8 mmol of Bi(NO3)3•5H2O and 1.8 mmol of Pb(NO3)2 to 9 ml of 1mol / L nitric acid solution and stir for 100 min to form a homogeneous solution B.

[0058] (3) Add the homogeneous solution B dropwise into the microemulsion A, stir evenly (stir for 50 min), add 0.6 ml of 40% v / v glyoxal aqueous solution, and continue stirring for 40 min to obtain a mixed solution.

[0059] (4) Adjust the pH of the mixed solution to 9 with 2 mol / L NaOH aqueous solution, stir for 50 min, transfer the mixed solution to a high-pressure reactor for hydrothermal reaction, react for 7 h under the conditions of 2.0 MPa pressure and 140 ℃ temperature, cool to room temperature after the reaction is completed, take the solid after centrifugation, wash with deionized water and anhydrous ethanol respectively, and dry at 60 ℃ for 8 h to obtain defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst.

[0060] Example 5

[0061] (1) Dissolve 2 mmol of OmimCl and 0.4 g of Triton X-100 in 50 ml of deionized water and stir for 120 min to form microemulsion A.

[0062] (2) Add 2 mmol of Bi(NO3)3•5H2O and 2 mmol of Pb(NO3)2 to 10 ml of 1mol / L nitric acid solution in sequence, stir for 150 min to form a homogeneous solution B.

[0063] (3) Add the homogeneous solution B dropwise to the microemulsion A, stir until homogeneous (stir for 60 min), add 0.5 ml of 40% v / v glyoxal aqueous solution, and continue stirring for 50 min to obtain a mixed solution.

[0064] (4) Adjust the pH of the mixed solution to 11 with 2 mol / L NaOH aqueous solution, stir for 60 min, transfer the mixed solution to a high-pressure reactor for hydrothermal reaction, react for 8 h under the conditions of 2.5 MPa pressure and 150 ℃ temperature, cool to room temperature after the reaction is completed, centrifuge and take the solid, wash with deionized water and anhydrous ethanol respectively, and dry at 60 ℃ for 9 h to obtain defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst.

[0065] Application Example 1

[0066] The photocatalytic activity of defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalysts prepared in Examples 1, 2, 3, 4, and 5, and the PbBiO2Cl nanosheet photocatalyst prepared in Example 1, was evaluated for CO2 reduction to CO. The activity evaluation experiments were conducted in a low-temperature constant-temperature water bath at 5 °C, using a 300W xenon lamp (bulb model PE300BF) equipped with a 400 nm cutoff filter as the light source. The gaseous products generated by the reaction were detected online by a gas chromatograph equipped with an FID detector and a capillary column. The specific operating steps are as follows:

[0067] 20 mg of the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst prepared in Examples 1, 2, 3, 4, and 5, and the PbBiO2Cl nanosheet photocatalyst prepared in Example 1, were weighed and dispersed in a quartz reactor containing approximately 10 mL of H2O. High-purity CO2 was then bubbled into the reaction system three times to remove air from the reactor. The peak area of ​​the product was recorded every 1 hour based on the peak elution time, and the yield was calculated according to the product standard curve. Finally, the cumulative CO yield of the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst and the PbBiO2Cl nanosheet photocatalyst under 4 hours of illumination was measured, and their average formation rate was calculated accordingly.

[0068] The average CO formation rate was determined online using a gas chromatograph equipped with a flame ionization detector and a thermal conductivity detector. The peak area of ​​the CO product was used in conjunction with the product standard curve (see...). Figure 7 CO production can be directly obtained from this.

[0069] Figure 4 Figure a shows the photocatalytic CO2 reduction activity of the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst prepared in Example 1; Figure b shows the photocatalytic CO2 reduction activity of the PbBiO2Cl nanosheet photocatalyst prepared in Example 1. As can be seen from the figures, within 4 h, the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst exhibits higher CO2 reduction activity than the PbBiO2Cl nanosheet photocatalyst. Calculations show that the CO2 reduction rate to CO production using the PbBiO2Cl nanosheet photocatalyst is 1.7 μmol g. -1 h -1 Meanwhile, the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst exhibits a CO reduction rate as high as 28.3 μmol g / L. -1 h -1 .

[0070] The defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst obtained in Example 2 achieved a photocatalytic CO2 reduction to CO production rate of 27.5 μmol g. -1 h -1 The photocatalytic CO2 reduction to CO rate of the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst obtained in Example 3 was 27.9 μmol g. -1 h -1 The photocatalytic CO2 reduction to CO rate of the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst obtained in Example 4 was 27.1 μmol g. -1 h -1 The photocatalytic CO2 reduction to CO rate of the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst obtained in Example 5 was 28.0 μmol g. -1 h -1 The defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst prepared in Example 1 exhibited the best photocatalytic CO2 reduction activity.

[0071] Application Example 2

[0072] The photocatalytic degradation activity of Rhodamine B by the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalysts prepared in Examples 1, 2, 3, 4, and 5, and the PbBiO2Cl nanosheet photocatalyst prepared in Example 1, was evaluated. The activity evaluation experiments were conducted in a DW-03 photochemical reactor, using an Xe lamp to simulate solar energy. Ultraviolet light was filtered out, and the degradation rate of Rhodamine B by the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst and the PbBiO2Cl nanosheet photocatalyst under visible solar light was measured. The specific operating steps are as follows:

[0073] 100 mL of Rhodamine B solution (10 mg / L) was added to the reactor and its initial absorbance was measured. 20 mg each of the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst prepared in Examples 1, 2, 3, 4, and 5, and the PbBiO2Cl nanosheet photocatalyst prepared in Example 1, were weighed and added to the above Rhodamine B solution. The mixture was stirred in the dark for 30 min. After desorption equilibrium was reached, the Xe lamp light source was turned on, and samples were taken every 10 min. After centrifugation, the absorbance of the supernatant was measured at the maximum absorption wavelength of the Rhodamine B solution (553 nm) to determine the degradation rate of Rhodamine B by the photocatalyst within 60 min.

[0074] The degradation rate is calculated using the following formula: R % = (C0 - C) / C0 × 100%, where C0 is the initial concentration of Rhodamine B, and C is the concentration of Rhodamine B at different sampling times after the start of degradation; the concentration of Rhodamine B is obtained from the absorbance measured by a UV-Vis spectrophotometer.

[0075] Figure 5 Figure a shows the photocatalytic degradation activity curve of Rhodamine B by the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst prepared in Example 1; Figure b shows the photocatalytic degradation activity curve of Rhodamine B by the PbBiO2Cl nanosheet photocatalyst prepared in Example 1. As can be seen from the figures, within 60 min, the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst exhibits higher degradation activity than the PbBiO2Cl nanosheet photocatalyst. Calculations show that the degradation rate of Rhodamine B by the PbBiO2Cl nanosheet photocatalyst is only 9.2%, while the degradation rate by the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst is 96.2%.

[0076] Within 60 min, the photocatalytic degradation rate of Rhodamine B by the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst obtained in Example 2 was 95.3%; the photocatalytic degradation rate of Rhodamine B by the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst obtained in Example 3 was 96.0%; the photocatalytic degradation rate of Rhodamine B by the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst obtained in Example 4 was 95.8%; and the photocatalytic degradation rate of Rhodamine B by the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst obtained in Example 5 was 95.7%. The photocatalytic degradation activity of Rhodamine B by the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst prepared in Example 1 was the best.

[0077] Application Example 3

[0078] The defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst prepared in Example 1 was subjected to photocatalytic CO2 reduction cycle activity and photocatalytic degradation of Rhodamine B cycle activity experiments.

[0079] (1) Photocatalytic CO2 reduction cycle activity experiment: The prepared defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst was continuously irradiated for 20 hours and analyzed online by a gas chromatograph equipped with a hydrogen flame ionization detector and a thermal conductivity detector. The photocatalytic CO2 reduction activity was obtained based on the peak area of ​​the product. The cycle activity was evaluated by whether the CO product could continue to increase.

[0080] (2) Cyclic activity experiment of photocatalytic degradation of Rhodamine B: After the degradation reaction was completed, the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst was centrifuged, the separated photocatalyst solid was collected and dried, and the dried photocatalyst was subjected to degradation reaction again. Cyclic degradation was used to evaluate the cyclic stability of the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst.

[0081] Figure 6 Figure a shows the photocatalytic CO2 reduction cycle activity of the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst prepared in Example 1; Figure b shows the photocatalytic degradation cycle activity of the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst prepared in Example 1. As can be seen from the figures, the defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst exhibits excellent cycle stability in both CO2 reduction and Rhodamine B degradation.

[0082] This invention provides a defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst, its preparation method, and its application. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A method for preparing a defect-rich PbBiO2Cl ultrathin hollow bowl-shaped photocatalyst, characterized in that, The preparation method comprises the following steps: (1) dissolving 1-octyl-3-methyl imidazole chloride and Triton X-100 in water, stirring uniformly to obtain a microemulsion A; (2) adding bismuth nitrate and lead nitrate into a nitric acid solution, stirring uniformly to obtain a solution B; (3) adding the solution B into the microemulsion A, stirring uniformly, then adding an aqueous glyoxal solution, continuing to stir uniformly to obtain a mixed solution; (4) adjusting the pH of the mixed solution to alkaline by using an aqueous NaOH solution, then performing a hydrothermal reaction, after the reaction, performing centrifugation, washing and drying to obtain a defect-rich PbBiO2Cl ultra-thin hollow bowl-shaped photocatalyst.

2. The production method according to claim 1, characterized by, In step (1), the amount ratio of 1-octyl-3-methyl imidazole chloride, Triton X-100 and water is 1-2 mmol:0.2-0.4 g:25-50 mL.

3. The method of claim 1, wherein the method is characterized by, In step (2), the amount ratio of bismuth nitrate, lead nitrate and the nitric acid solution is 1-2 mmol:1-2 mmol:5-10 mL; the concentration of the nitric acid solution is 0.5-1.5 mol / L.

4. The method of claim 1, wherein, In step (3), the volume ratio of the solution B, the microemulsion A and the aqueous glyoxal solution is 1:5:0.12-0.05; the mass fraction of the aqueous glyoxal solution is 30%-50%.

5. The preparation method according to claim 1, characterized in that, In step (4), the concentration of the aqueous NaOH solution is 1.5-2.5 mol / L; the alkalinity has a pH value of 9-11.

6. The method of claim 1, wherein, In step (4), the temperature of the hydrothermal reaction is 110-150℃, the reaction time is 4-8 h, the reaction pressure is 2.0-3.0 MPa; and / or, the washing is performed by using deionized water and anhydrous ethanol respectively; the drying is performed at a temperature of 50-70℃ for 6-10 h.

7. The defect-rich PbBiO2Cl ultra-thin hollow bowl-shaped photocatalyst prepared by the preparation method in any one of claims 1-6. 8.The defect-rich PbBiO2Cl ultrathin hollow bowl-like photocatalyst according to claim 7, characterized in that, The defect-rich PbBiO2Cl ultra-thin hollow bowl-shaped photocatalyst has a concave bowl-shaped structure and a particle size of 0.5-1 μm.

9. The defect-rich PbBiO2Cl ultra-thin hollow bowl-shaped photocatalyst in claim 7 is applied to a photocatalytic CO2 reduction reaction.

10. The defect-rich PbBiO2Cl ultra-thin hollow bowl-shaped photocatalyst in claim 7 is applied to degradation of water pollutants.

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