A water-stable perovskite CsPbI3@PVP photocatalyst, its preparation method and application
By encapsulating CsPbI3 in hydrophilic polymer PVP, the chemical stability and photocatalytic performance of perovskite CsPbI3 are enhanced, solving the instability problem of perovskite in water and gas environments and achieving a highly efficient photocatalytic degradation effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- GUILIN UNIV OF AEROSPACE TECH
- Filing Date
- 2023-06-02
- Publication Date
- 2026-05-29
Smart Images
Figure CN116673071B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of photocatalytic materials technology, and in particular to a water-stable perovskite CsPbI3@PVP photocatalyst, its preparation method, and its application. Background Technology
[0002] Metal halide perovskites, similar to metal chalcogenides, have been identified as promising photocatalysts due to their simple synthesis methods and compositional engineering, strong visible light trapping ability, tunable band gap, long charge carrier diffusion length, low trap density, high charge carrier mobility, and suitable band edge positions. However, the relatively low formation enthalpy of perovskites makes them susceptible to structural damage under external conditions such as oxygen, polar solvents, and high-temperature environments. This instability severely limits the widespread application of perovskites.
[0003] Stability plays a crucial role in liquid-phase and gas-phase photocatalysis involving perovskites. Although all-inorganic perovskites exhibit greater thermal stability than organometallic structures, their utilization remains a challenge due to their highly polar ionic structure.
[0004] To avoid the influence of polar solvents such as water on perovskites, existing technologies primarily employ encapsulation techniques. This involves encapsulating the perovskite surface with a coating material to reduce or prevent the perovskite from being affected by external moisture or gases. The encapsulation materials used in existing technologies mainly fall into two categories: one is inorganic oxides such as SiO2, TiO2, and Al2O3; the other is organic polymers such as polystyrene (PS), polymethyl methacrylate (PMMA), and polyvinylidene fluoride (PVDF). However, most of these materials are electrically insulating. While encapsulation can reduce the impact of polar solvents like water to some extent, it also hinders charge extraction and transport in the perovskite, making it difficult to apply encapsulated perovskite materials to fields such as photocatalysis, photoelectrocatalysis, and solar cells.
[0005] Therefore, this invention provides a water-stable perovskite CsPbI3@PVP photocatalyst, its preparation method, and its application. Summary of the Invention
[0006] To address the shortcomings of the prior art, this invention provides a water-stable perovskite CsPbI3@PVP photocatalyst, its preparation method, and its applications. This invention encapsulates CsPbI3 in a hydrophilic polymer PVP, utilizing PVP to passivate the CsPbI3 surface. The oxygen and nitrogen atoms in the acyl and amine groups of the PVP molecule have isolated electron pairs, providing coordination centers. Furthermore, the PVP molecules attract cesium ions from CsPbI3. Over time, the binding of PVP and CsPbI3 contributes to the enhancement of the surface electron cloud density of CsPbI3, thereby reducing its surface energy. This allows the PVP-functionalized CsPbI3 of this invention to maintain chemical stability while simultaneously improving its photocatalytic performance, enabling its application in photocatalysis, photoelectrocatalysis, and solar cells.
[0007] The present invention relates to a water-stable perovskite CsPbI3@PVP photocatalyst, its preparation method, and its application, which are achieved through the following technical solutions:
[0008] The first objective of this invention is to provide a method for preparing a water-stable perovskite CsPbI3@PVP photocatalyst, comprising the following steps:
[0009] By using hydrophilic polymer PVP as the encapsulation material, CsPbI3 is encapsulated in hydrophilic polymer PVP, thus obtaining a water-stable perovskite CsPbI3@PVP photocatalyst.
[0010] Furthermore, the encapsulation is performed through the following steps:
[0011] Step 1: The hydrophilic polymer PVP is uniformly dispersed in an organic solvent to obtain an encapsulation solution;
[0012] Step 2: CsPbI3 is added to the encapsulation solution and stirred at room temperature, followed by ultrasonic treatment, filtration, washing and drying to obtain the water-stable perovskite CsPbI3@PVP photocatalyst.
[0013] Furthermore, the organic solvent is ethanol.
[0014] Furthermore, the ratio of the organic solvent to the hydrophilic polymer PVP is 20 mL: 1–3 g.
[0015] Furthermore, the ratio of CsPbI3 to the encapsulation solution is 9.5–10.5 mmol: 20 mL.
[0016] Furthermore, the stirring rate of the stirring process is 1000-1200 r / min, and the stirring time is 20-40 min.
[0017] Furthermore, the ultrasonic frequency of the ultrasonic treatment is 35-45 kHz, the ultrasonic power is 360 W, and the ultrasonic time is 10-20 min.
[0018] Furthermore, the CsPbI3 is prepared through the following steps:
[0019] S1, PbI2 is uniformly dispersed in hydroiodic acid to obtain solution A;
[0020] S2, CsI is uniformly dispersed in an aqueous solvent to obtain solution B;
[0021] S3, add solution B dropwise to solution A, filter, and the obtained brown solid phase component is CsPbI3;
[0022] Wherein, the volume ratio of solution B to solution A is 2 to 4:8;
[0023] Furthermore, in solution A, the ratio of PbI2 to hydroiodic acid is 10 mmol: 7-9 mL;
[0024] In solution B, the ratio of CsI to water solvent is 10 mmol: 2-4 mL.
[0025] The second objective of this invention is to provide a water-stable perovskite CsPbI3@PVP photocatalyst prepared by the above-described preparation method.
[0026] A third objective of this invention is to provide the application of the aforementioned water-stable perovskite CsPbI3@PVP photocatalyst in the degradation of dyes in water.
[0027] Compared with the prior art, the present invention has the following advantages:
[0028] By encapsulating CsPbI3 in the hydrophilic polymer PVP, the photocatalytic degradation of CsPbI3 in water was successfully achieved. The direct bandgap semiconductor CsPbI3 was used in a high-efficiency photocatalytic degradation experiment, achieving for the first time a perovskite dye degradation efficiency of 100% Rhodamine b degradation in 20 minutes. Attached Figure Description
[0029] Figure 1 TEM image of the perovskite CsPbI3@PVP photocatalyst prepared in Example 1;
[0030] Figure 2 The dispersion and luminescence of the materials obtained in Example 1 and Comparative Example 1 after mixing with deionized water at different standing times are shown; wherein, Figure 2 (a) The dispersion of the materials obtained in Example 1 and Comparative Example 1 under sunlight after being mixed with deionized water; Figure 2 (b) to Figure 2 (d) The luminescence of the materials obtained in Example 1 and Comparative Example 1 under ultraviolet light after being mixed with deionized water for 1 Day, 7 Days and 30 Days, respectively;
[0031] Figure 3 The fluorescence spectra of the materials obtained in Example 1 and Comparative Example 1 after mixing with deionized water for 1 Day, 7 Days and 30 Days are shown.
[0032] Figure 4 The changes in the degree of degradation of Rhodamine b by the perovskite CsPbI3@PVP photocatalyst prepared in Example 1 at different degradation times;
[0033] Figure 5 The degradation of different concentrations of rhodamine b by the perovskite CsPbI3@PVP photocatalyst prepared in Example 1. Detailed Implementation
[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below.
[0035] This invention provides a water-stable perovskite CsPbI3@PVP photocatalyst, and its preparation method is as follows:
[0036] Using hydrophilic polymer PVP as the encapsulation material, CsPbI3 is encapsulated within the hydrophilic polymer PVP, thus obtaining a water-stable perovskite CsPbI3@PVP photocatalyst. Specifically, this invention involves the following encapsulation steps:
[0037] Step 1: The hydrophilic polymer PVP is uniformly dispersed in an organic solvent to obtain an encapsulation solution;
[0038] It should be noted that the organic solvent used in this invention should meet the following two conditions: first, it should be able to maintain the perovskite activity of CsPbI3 in the solvent; second, it should have good solubility in the encapsulation material PVP of this invention, so that the encapsulation material PVP can encapsulate the perovskite CsPbI3 in the organic solvent, while the solvent will not affect the activity of CsPbI3. Considering the economic benefits and availability of raw materials, this invention preferably uses ethanol as the organic solvent. Furthermore, to ensure the encapsulation effect of the polymer PVP, the preferred ratio of organic solvent to hydrophilic polymer PVP is 20 mL: 1–3 g.
[0039] Step 2: CsPbI3 is added to the encapsulation solution and stirred at room temperature. Then, it is subjected to ultrasonic treatment, filtered, washed and dried to obtain the water-stable perovskite CsPbI3@PVP photocatalyst.
[0040] It should be noted that, in order to ensure that the PVP in the encapsulation solution can uniformly encapsulate CsPbI3, the preferred ratio of CsPbI3 to the encapsulation solution is 9.5–10.5 mmol: 20 mL. Furthermore, after adding CsPbI3 to the encapsulation solution, the mixture is stirred vigorously to ensure sufficient contact between PVP and CsPbI3, which is beneficial for the subsequent complete encapsulation of each micron-sized CsPbI3 crystal by PVP. This invention does not limit the specific stirring rate, as long as it ensures sufficient contact and encapsulation between PVP and CsPbI3 in the solution system; for example, a stirring rate of 300–500 r / min can be selected for stirring for 20–40 min.
[0041] This invention involves ultrasonic treatment following stirring to achieve better bonding between PVP and CsPbI3 under ultrasonic action, thereby improving the encapsulation effect of PVP on CsPbI3. The ultrasonic treatment is performed at a frequency of 35–45 kHz, with an ultrasonic power of 360 W and a duration of 10–20 minutes.
[0042] It should be noted that this invention does not limit the specific drying process conditions, as long as excess solvent and washing are removed from the product surface. For example, drying can be carried out at 50–70°C for 6–24 hours.
[0043] It should also be noted that the CsPbI3 used in this invention is prepared through the following steps:
[0044] S1, PbI2 is uniformly dispersed in hydroiodic acid to obtain solution A;
[0045] S2, CsI is uniformly dispersed in an aqueous solvent to obtain solution B;
[0046] S3, add solution B dropwise to solution A, filter, and the obtained brown solid phase component is CsPbI3;
[0047] Wherein, the volume ratio of solution B to solution A is 2 to 4:8;
[0048] Furthermore, in solution A, the ratio of PbI2 to hydroiodic acid is 10 mmol: 7-9 mL;
[0049] In solution B, the ratio of CsI to water solvent is 10 mmol: 2-4 mL.
[0050] Example 1
[0051] This embodiment provides a water-stable perovskite CsPbI3@PVP photocatalyst, and its preparation method is as follows:
[0052] Step 1: Preparation of CsPbI3
[0053] 1) Dissolve PbI2 (10 mmol, 3.67 g) in hydroiodic acid (8 mL) to obtain solution A;
[0054] 2) Dissolve CsI (10 mmol, 2.12 g) in 3 mL of deionized water to obtain solution B;
[0055] 3) Add the solution B prepared above dropwise to the solution A obtained above. During the dropwise addition, a brown precipitate can be observed to form. After the addition is complete, filter the solution. The brown solid phase obtained is the CsPbI3.
[0056] Step 2, encapsulate CsPbI3
[0057] 1) Disperse 2g of hydrophilic polymer PVP uniformly in 20mL of ethanol to obtain an encapsulation solution;
[0058] 2) The CsPbI3 obtained in step one above is added to the encapsulation solution obtained above and stirred at a stirring rate of 1100 r / min for 30 min at room temperature. Then, it is sonicated for 15 min under ultrasonic conditions of ultrasonic frequency of 40 kHz and ultrasonic power of 360 W. After filtration, the solid phase obtained by filtration is washed twice with ethanol and water alternately to remove unreacted raw materials and impurities. Then, it is dried in a vacuum oven at 60 °C for 12 h to obtain water-stable perovskite CsPbI3@PVP photocatalyst.
[0059] Example 2
[0060] This embodiment provides a water-stable perovskite CsPbI3@PVP photocatalyst, and its preparation method is as follows:
[0061] Step 1: Preparation of CsPbI3
[0062] 1) Dissolve PbI2 (10 mmol, 3.67 g) in hydroiodic acid (8 mL) to obtain solution A;
[0063] 2) Dissolve CsI (10 mmol, 2.12 g) in 3 mL of deionized water to obtain solution B;
[0064] 3) Add the solution B prepared above dropwise to the solution A obtained above. During the dropwise addition, a brown precipitate can be observed to form. After the addition is complete, filter the solution. The brown solid phase obtained is the CsPbI3.
[0065] Step 2, encapsulate CsPbI3
[0066] 1) Disperse 1g of hydrophilic polymer PVP uniformly in 20mL of ethanol to obtain an encapsulation solution;
[0067] 2) The CsPbI3 obtained in step one above is added to the encapsulation solution obtained above and stirred at a stirring rate of 1000 r / min for 40 min at room temperature. Then, it is sonicated for 10 min under ultrasonic conditions of 40 kHz and 360 W. After filtration, the solid phase obtained by filtration is washed twice with ethanol and water alternately to remove unreacted raw materials and impurities. Then, it is dried in a vacuum oven at 60 °C for 12 h to obtain water-stable perovskite CsPbI3@PVP photocatalyst.
[0068] Example 3
[0069] This embodiment provides a water-stable perovskite CsPbI3@PVP photocatalyst, and its preparation method is as follows:
[0070] Step 1: Preparation of CsPbI3
[0071] 1) Dissolve PbI2 (10 mmol, 3.67 g) in hydroiodic acid (8 mL) to obtain solution A;
[0072] 2) Dissolve CsI (10 mmol, 2.12 g) in 3 mL of deionized water to obtain solution B;
[0073] 3) Add the solution B prepared above dropwise to the solution A obtained above. During the dropwise addition, a brown precipitate can be observed to form. After the addition is complete, filter the solution. The brown solid phase obtained is the CsPbI3.
[0074] Step 2, encapsulate CsPbI3
[0075] 1) Disperse 3g of hydrophilic polymer PVP uniformly in 20mL of ethanol to obtain an encapsulation solution;
[0076] 2) The CsPbI3 obtained in step one above is added to the encapsulation solution obtained above and stirred at a stirring rate of 1200 r / min for 20 min at room temperature. Then, it is sonicated for 20 min under ultrasonic conditions of ultrasonic frequency of 40 kHz and ultrasonic power of 360 W. After filtration, the solid phase obtained by filtration is washed twice with ethanol and water alternately to remove unreacted raw materials and impurities. Then, it is dried in a vacuum oven at 60 ℃ for 12 h to obtain water-stable perovskite CsPbI3@PVP photocatalyst.
[0077] Example 4
[0078] This embodiment provides a water-stable perovskite CsPbI3@PVP photocatalyst, and its preparation method is as follows:
[0079] Step 1: Preparation of CsPbI3
[0080] 1) Dissolve PbI2 (10 mmol, 3.67 g) in hydroiodic acid (7 mL) to obtain solution A;
[0081] 2) Dissolve CsI (10 mmol, 2.12 g) in 2 mL of deionized water to obtain solution B;
[0082] 3) Add the solution B prepared above dropwise to the solution A obtained above. During the dropwise addition, a brown precipitate can be observed to form. After the addition is complete, filter the solution. The brown solid phase obtained is the CsPbI3.
[0083] Step 2, encapsulate CsPbI3
[0084] 1) Disperse 2g of hydrophilic polymer PVP uniformly in 20mL of ethanol to obtain an encapsulation solution;
[0085] 2) The CsPbI3 obtained in step one above is added to the encapsulation solution obtained above and stirred at a stirring rate of 1100 r / min for 30 min at room temperature. Then, it is sonicated for 15 min under ultrasonic conditions of 35 kHz and 360 W. After filtration, the solid phase obtained by filtration is washed twice with ethanol and water alternately to remove unreacted raw materials and impurities. Then, it is dried in a vacuum oven at 60 °C for 12 h to obtain water-stable perovskite CsPbI3@PVP photocatalyst.
[0086] Example 5
[0087] This embodiment provides a water-stable perovskite CsPbI3@PVP photocatalyst, and its preparation method is as follows:
[0088] Step 1: Preparation of CsPbI3
[0089] 1) Dissolve PbI2 (10 mmol, 3.67 g) in hydroiodic acid (9 mL) to obtain solution A;
[0090] 2) Dissolve CsI (10 mmol, 2.12 g) in 4 mL of deionized water to obtain solution B;
[0091] 3) Add the solution B prepared above dropwise to the solution A obtained above. During the dropwise addition, a brown precipitate can be observed to form. After the addition is complete, filter the solution. The brown solid phase obtained is the CsPbI3.
[0092] Step 2, encapsulate CsPbI3
[0093] 1) Disperse 2g of hydrophilic polymer PVP uniformly in 20mL of ethanol to obtain an encapsulation solution;
[0094] 2) The CsPbI3 obtained in step one above is added to the encapsulation solution obtained above and stirred at a stirring rate of 1100 r / min for 20 min at room temperature. Then, it is sonicated for 20 min under ultrasonic conditions of 45 kHz and 360 W. After filtration, the solid phase obtained by filtration is washed twice with ethanol and water alternately to remove unreacted raw materials and impurities. Then, it is dried in a vacuum oven at 60 °C for 12 h to obtain water-stable perovskite CsPbI3@PVP photocatalyst.
[0095] Example 6
[0096] This embodiment provides a water-stable perovskite CsPbI3@PVP photocatalyst, and its preparation method is as follows:
[0097] Step 1: Preparation of CsPbI3
[0098] 1) Dissolve PbI2 (10 mmol, 3.67 g) in hydroiodic acid (8 mL) to obtain solution A;
[0099] 2) Dissolve CsI (10 mmol, 2.12 g) in 3 mL of deionized water to obtain solution B;
[0100] 3) Add the solution B prepared above dropwise to the solution A obtained above. During the dropwise addition, a brown precipitate can be observed to form. After the addition is complete, filter the solution. The brown solid phase obtained is the CsPbI3.
[0101] Step 2, encapsulate CsPbI3
[0102] 1) Disperse 2g of hydrophilic polymer PVP uniformly in 20mL of ethanol to obtain an encapsulation solution;
[0103] 2) Take 9.5 mmol of CsPbI3 obtained in step one above and add it to the encapsulation solution obtained above. Stir at 1100 r / min for 30 min at room temperature. Then sonicate for 15 min under ultrasonic conditions of 40 kHz and 360 W. Filter and wash the filtered solid phase twice with ethanol and water alternately to remove unreacted raw materials and impurities. Then dry in a vacuum oven at 60 °C for 12 h to obtain water-stable perovskite CsPbI3@PVP photocatalyst.
[0104] Example 7
[0105] This embodiment provides a water-stable perovskite CsPbI3@PVP photocatalyst, and its preparation method is as follows:
[0106] Step 1: Preparation of CsPbI3
[0107] 1) Dissolve PbI2 (10 mmol, 3.67 g) in hydroiodic acid (8 mL) to obtain solution A;
[0108] 2) Dissolve CsI (10 mmol, 2.12 g) in 3 mL of deionized water to obtain solution B;
[0109] 3) Add the solution B prepared above dropwise to the solution A obtained above. During the dropwise addition, a brown precipitate can be observed to form. After the addition is complete, filter the solution. The brown solid phase obtained is the CsPbI3.
[0110] Step 2, encapsulate CsPbI3
[0111] 1) Disperse 2g of hydrophilic polymer PVP uniformly in 20mL of ethanol to obtain an encapsulation solution;
[0112] 2) Take 10.5 mmol of CsPbI3 obtained in step one above and add it to the encapsulation solution obtained above. Stir at 1100 r / min for 30 min at room temperature. Then sonicate for 15 min at an ultrasonic frequency of 40 kHz and an ultrasonic power of 360 W. Filter and wash the filtered solid phase twice with ethanol and water alternately to remove unreacted raw materials and impurities. Then dry in a vacuum oven at 60 °C for 12 h to obtain water-stable perovskite CsPbI3@PVP photocatalyst.
[0113] Comparative Example 1
[0114] The only difference between this comparative example and Example 1 is that:
[0115] Encapsulation is performed without adding any encapsulation material.
[0116] Experimental Section
[0117] (I) Morphological Test
[0118] This invention takes the perovskite CsPbI3@PVP photocatalyst material prepared in Example 1 as an example, and performs transmission electron microscopy (TEM) tests on it. The test results are as follows: Figure 1 As shown.
[0119] Depend on Figure 1It can be seen that the perovskite CsPbI3@PVP photocatalyst material prepared by this invention successfully encapsulates CsPbI3 with PVP.
[0120] (II) Water stability test
[0121] Taking the materials obtained in Example 1 and Comparative Example 1 as examples, 10 mg of each material was placed in 10 mL of deionized water, and their dispersion and luminescence at different standing times after mixing were observed. The results are as follows. Figure 2 and Figure 3 As shown.
[0122] Figure 2 The dispersion and luminescence of the materials obtained in Example 1 and Comparative Example 1 after mixing with deionized water at different standing times are shown. Figure 2 (a) The dispersion of the materials obtained in Example 1 and Comparative Example 1 after mixing with deionized water under sunlight. It can be seen that the CsPbI3 in Comparative Example 1 has a large amount of precipitation and agglomeration in water and poor dispersibility in water; while the CsPbI3@PVP in Example 1 is uniformly dispersed in water without agglomeration, indicating that the CsPbI3@PVP prepared in Example 1 of the present invention has water stability. Figure 2 (b) to Figure 2 (d) The luminescence of the materials obtained in Example 1 and Comparative Example 1 under ultraviolet light after being mixed with deionized water for 1 Day, 7 Day and 30 Day respectively. It can be seen that the CsPbI3@PVP prepared in Example 1 of the present invention emits green light obviously, and the luminescence does not change significantly over time, indicating that the luminescence performance of CsPbI3@PVP prepared in Example 1 of the present invention is stable.
[0123] The present invention also uses the materials obtained in Example 1 and Comparative Example 1 as examples, and performs fluorescence spectroscopy tests on samples after mixing them with deionized water for 1 Day, 7 Day, and 30 Day, respectively, and the test results are as follows. Figure 3 As shown. By Figure 3It can be seen that the luminescence center of CsPbI3 in Comparative Example 1 is at 526 nm, while the luminescence center of CsPbI3@PVP in Example 1 is at 530 nm. Furthermore, it can be observed that the fluorescence intensity of CsPbI3 in Comparative Example 1 gradually decreases over time, while the fluorescence intensity of CsPbI3@PVP in Example 1 increases slightly but not significantly. This indicates that the luminescence performance of CsPbI3@PVP in Example 1 is more stable, while the luminescence performance stability of CsPbI3 in Comparative Example 1 is poor. Moreover, comparing the fluorescence intensity of Example 1 and Comparative Example 1 over 1 day shows that the fluorescence intensity of CsPbI3@PVP in Example 1 is significantly greater than that of CsPbI3 in Comparative Example 1. In conclusion, by using PVP encapsulation of CsPbI3 in this invention, its luminescence performance and stability are significantly improved.
[0124] (III) Photocatalytic Degradation Performance Test
[0125] This invention uses the perovskite CsPbI3@PVP photocatalyst prepared in Example 1 as a catalyst and Rhodamine b at a concentration of 10 mg / L as the target to be degraded, to explore the degradation effect of different catalyst dosages on Rhodamine b.
[0126] Four experimental groups were set up. 50 mL of 10 mg / L rhodamine b was added to each group, along with 25 mg, 37.5 mg, 50 mg, and 62.5 mg of the perovskite CsPbI3@PVP photocatalyst prepared in Example 1, respectively. Samples were taken after 30 min of dark reaction (recorded as 0 min), and then at intervals of 5 min, 10 min, 15 min, and 20 min. The changes in the degradation rate of rhodamine b were recorded, and the results are shown below. Figure 4 As shown.
[0127] And by Figure 4 It can be seen that with the increase of photocatalyst dosage, the degradation rate of Rhodamine B is faster and the degradation effect is better.
[0128] The present invention also uses the perovskite CsPbI3@PVP photocatalyst prepared in Example 1 as a catalyst, and uses different concentrations of rhodamine b as the target to be degraded, to explore the degradation effect of the catalyst on different concentrations of rhodamine b.
[0129] Four experimental groups were set up. For each group, 50 mL of 10 mg / L rhodamine b, 50 mL of 20 mg / L rhodamine b, 50 mL of 30 mg / L rhodamine b, and 50 mL of 40 mg / L rhodamine b were respectively added. Additionally, 50 mg of the perovskite CsPbI3@PVP photocatalyst prepared in Example 1 was added to each group. A sample was taken after 30 min of dark reaction (recorded as 0 min). Samples were then taken at intervals of 5 min, 10 min, 15 min, and 20 min to record the changes in the degradation rate of rhodamine b. These records are shown below. Figure 5 As shown.
[0130] And by Figure 5 It can be seen that the perovskite CsPbI3@PVP photocatalyst prepared in Example 1 of the present invention can degrade different concentrations of rhodamine b within 20 minutes (after 30 minutes of dark reaction treatment), indicating that the perovskite CsPbI3@PVP photocatalyst prepared in Example 1 of the present invention has a good degradation effect on rhodamine b.
[0131] Obviously, the above embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.
Claims
1. A method for preparing a water-stable perovskite CsPbI3@PVP photocatalyst, characterized in that, Includes the following steps: Using hydrophilic polymer PVP as the encapsulation material, CsPbI3 is encapsulated in hydrophilic polymer PVP, thus obtaining a water-stable perovskite CsPbI3@PVP photocatalyst. Step 1: The hydrophilic polymer PVP is uniformly dispersed in an organic solvent to obtain an encapsulation solution; the ratio of the organic solvent to the hydrophilic polymer PVP is 20 mL: 1~3 g. Step 2: CsPbI3 is added to the encapsulation solution and stirred at room temperature, followed by ultrasonic treatment, filtration, washing and drying to obtain the water-stable perovskite CsPbI3@PVP photocatalyst; the ratio of CsPbI3 to the encapsulation solution is 9.5~10.5 mmol:20 mL.
2. The preparation method according to claim 1, characterized in that, The organic solvent is ethanol.
3. The preparation method according to claim 1, characterized in that, The stirring rate of the stirring process is 1000~1200 r / min, and the stirring time is 20~40 min.
4. The preparation method according to claim 1, characterized in that, The ultrasonic treatment uses an ultrasonic frequency of 35-45 kHz and an ultrasonic time of 10-20 min.
5. The preparation method according to claim 1, characterized in that, The CsPbI3 is prepared through the following steps: S1, PbI2 is uniformly dispersed in hydroiodic acid to obtain solution A; S2, CsI is uniformly dispersed in an aqueous solvent to obtain solution B; S3, add solution B dropwise to solution A, filter, and the obtained brown solid phase component is CsPbI3; Wherein, the volume ratio of solution B to solution A is 2~4:8; Furthermore, in solution A, the ratio of PbI2 to hydroiodic acid is 10 mmol: 7~9 mL; In solution B, the ratio of CsI to water solvent is 10 mmol: 2~4 mL.
6. A water-stable perovskite CsPbI3@PVP photocatalyst prepared by the preparation method according to any one of claims 1-5.
7. The application of the water-stable perovskite CsPbI3@PVP photocatalyst of claim 6 in the degradation of dyes in water.