Hydrogen-bond-rich network photocatalytic membrane and preparation method thereof

Abstract

The invention discloses a hydrogen-bond-rich network photocatalytic membrane and a preparation method thereof.Membrane materials comprise urea CO (NH2) 2, potassium hydroxide KOH, methyl ammonium bromide MABr, lead bromide PbBr2 ethyl cellulose ECE, ethyl acetate C4H8O2, dimethyl sulfoxide DMSO and isopropyl alcohol IPA. In the forming process of the photocatalytic membrane,-OH groups in ECE molecules not only form intermolecular hydrogen bonds with adjacent ECE molecules, but also form intermolecular hydrogen bonds with adjacent ECE molecules; in addition, N-H-O hydrogen bonds are formed with-CN and-NH2 groups in the MAPbBr3 / CN-g-C3N4, so that a highly interconnected hydrogen bond network is formed. Compared with H2O molecules, the network is easier to oxidize by photogenerated holes, proton coupling electron transfer is promoted, and a formation energy barrier of a * COOH intermediate is reduced.

Description

Technical Field

[0001] The present invention belongs to the field of photocatalytic materials, and particularly relates to a hydrogen-bond-rich network photocatalytic membrane and a preparation method thereof. Background Art

[0002] Photocatalytic reduction of CO2 to produce high-value fuels provides an innovative path to solve the greenhouse effect and energy crisis. Currently, the main products of this technology still focus on low-value-added CO, while CH4 with high energy density faces challenges in terms of insufficient yield and selectivity. Photocatalytic reduction of CO2 to produce CH4 includes two half-reactions: CO2 reduction and H2O oxidation. Its complex mechanism involves multi-stage proton-coupled electron transfer and the dynamic adsorption equilibrium of intermediate products. Therefore, regulating the proton transfer efficiency and the stability of key intermediates has become the key breakthrough point for improving the selectivity of CH4.

[0003] During the CO2 methanation reaction process, the initially formed *COOH intermediate plays an important role in the selectivity of CH4, and its formation process is restricted by the rate of proton-coupled electron transfer. Although the traditional H2O proton source is economical, it is limited by the sluggish kinetics of H2O oxidation, resulting in a relatively high energy barrier for the conversion of CO2 → *COOH. Therefore, a new type of solid-state proton source (such as alternative materials containing weak molecular interactions) can achieve controllable proton release through functional group oxidation, but the existing systems generally have the problem of insufficient proton supply persistence, and ultimately it is still difficult to break through the dominant position of CO products. It is worth noting that in the field of electrocatalysis, the special advantages of the hydrogen bond network have been confirmed - by constructing an interconnected structure formed by hydroxyl groups (-OH) and other proton donors and strongly electronegative proton acceptors (such as O, N), a "proton storage station" can be established, significantly improving the proton-coupled electron transfer efficiency and reducing the formation energy barrier of the *COOH intermediate.

[0004] In addition to the *COOH intermediate, *CO, as a key intermediate in the CO2 methanation process, its stability directly affects the product selectivity. The hydrogen bond network can not only efficiently provide protons, but also enhance the adsorption of *CO on the catalyst surface through CO···HO hydrogen bond interactions, thereby promoting subsequent hydrogenation to form CH4 rather than desorption to form CO. However, in the photocatalytic system, due to the characteristics of the gas-solid reaction interface, the construction of the hydrogen bond network is much more difficult than that of the liquid-solid electrocatalytic system, resulting in the research on the relevant intermediate regulation mechanism still being in its infancy. The breakthrough of this technical bottleneck requires the development of new modification strategies from the perspective of molecular engineering to achieve the precise construction and functional regulation of the hydrogen bond network in the heterogeneous system. Summary of the Invention

[0005] The purpose of the present invention is to design a hydrogen-bond-rich network photocatalytic membrane and a preparation method thereof to improve the yield and selectivity of photocatalytic reduction of CO2 to produce CH4.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows: The first object of the present invention is to propose a hydrogen-bond-rich network photocatalytic film, the material of which is composed of ethyl cellulose as the film-forming material, MAPbBr3 / CN-g-C3N4 heterojunction as the catalytic center, hydroxyl (-OH) groups in ethyl cellulose molecules as hydrogen-bond donors, and -CN and -NH2 groups in MAPbBr3 and CN-g-C3N4 molecules as hydrogen-bond acceptors. The material is prepared from urea CO(NH2)2, potassium hydroxide KOH, methylammonium bromide MABr, lead bromide PbBr2, ethyl cellulose ECE, ethyl acetate C4H8O2, dimethyl sulfoxide DMSO, and isopropyl alcohol IPA.

[0007] The second object of the present invention is to propose a preparation method of the hydrogen-bond-rich network photocatalytic film material as follows: First, prepare the catalytic center MAPbBr3 / CN-g-C3N4 Step 1: Dissolve a certain amount of CO(NH2)2 in a KOH solution, evaporate the water by heating to obtain a recrystallization mixture of CO(NH2)2 and KOH. Calcinate the obtained mixture in a muffle furnace at 400 - 800 °C for 4 - 10 h to obtain CN-g-C3N4 rich in cyano groups; Step 2: Dissolve MABr and PbBr2 in DMSO to prepare a perovskite precursor solution. Ultrasonically disperse the CN-g-C3N4 obtained in Step 1 in IPA for 1 - 4 h to prepare a CN-g-C3N4 dispersion. Drop a certain amount of the perovskite precursor solution into the IPA dispersion of CN-g-C3N4 and stir magnetically for 1 - 4 h. Collect the precipitate and wash it with IPA 5 - 10 times. After vacuum drying, anneal it at 100 - 180 °C for 10 - 60 min to obtain the MAPbBr3 / CN-g-C3N4 catalytic center; Step 3: Dissolve ECE in C4H8O2 to prepare a film precursor solution. Ultrasonically disperse the prepared MAPbBr3 / CN-g-C3N4 catalytic center in the ECE solution. Then take a certain amount of the ECE dispersion in a petri dish and dry it to obtain a MAPbBr3 / CN-g-C3N4 / ECE photocatalytic film rich in hydrogen bond network. During the drying process, the hydrogen-bond donors and acceptors in the MAPbBr3 / CN-g-C3N4 catalytic center and the ECE film material form a hydrogen bond network structure through self-assembly.

[0008] Furthermore, in Step 1, the mass of CO(NH2)2 is 5 - 50 mg, and the concentration of the KOH solution is 0.5 - 3 mg / mL.

[0009] Further, in step 2, the masses of MABr and PbBr2 are 10 - 60 mg and 50 - 200 mg respectively, the mass of CN-g-C3N4 is 10 - 200 mg, and the volumes of DMSO and IPA are 1 - 50 and 1 - 20 mL respectively.

[0010] Further, in step 3, the mass of ECE is 0.5 - 10 g, the dosage of C4H8O2 is 5 - 100 mL, and the mass of the MAPbBr3 / CN-g-C3N4 catalyst is 0.01 - 5 g.

[0011] Compared with the prior art, the present invention has the following beneficial effects: During the formation of the photocatalytic membrane, the -OH groups in the ECE molecules not only form intermolecular hydrogen bonds with adjacent ECE molecules, but also form N···H - O hydrogen bonds with the -CN and -NH2 groups in MAPbBr3 / CN-g-C3N4, thus forming a highly interconnected hydrogen bond network. This network is more easily oxidized by photogenerated holes than H2O molecules, promotes proton-coupled electron transfer, and reduces the formation energy barrier of the *COOH intermediate. At the same time, the hydrogen bond network stabilizes the *CO intermediate through the CO···HO interaction, promoting its further hydrogenation conversion rather than desorption to form CO products. Through the synergistic regulation of the two key intermediates *COOH and *CO, the selectivity of photocatalytic CO2 to CH4 conversion is increased from 0.4% to 82%. In addition, the MPB / CN-g-CN / ECE photocatalytic membrane has long-term stability and broad practical application prospects, and shows good stability during the cyclic test for 30 consecutive days (8 hours per day) under natural light and low CO2 concentration conditions.

[0012] During the construction of the MAPbBr3 / CN-g-C3N4 / ECE photocatalytic membrane system, the hydroxyl group (-OH) of the ECE molecule not only forms an intermolecular hydrogen bond of N···H - O by connecting with homologous molecules, but also forms an additional hydrogen bond of N - H···O with the cyano group (-CN) and amino group (-NH2) of the catalytic center of MAPbBr3 / CN-g-C3N4, thus constructing a hydrogen bond network structure. On the one hand, compared with the traditional H2O molecule proton donor, this hydrogen bond network is more easily oxidized to provide more protons, promotes the proton-coupled electron transfer process, and reduces the formation potential barrier of the *COOH intermediate. On the other hand, the hydrogen bond network structure improves the stability of the *CO intermediate on the catalyst surface through the CO···HO hydrogen bond interaction, driving the continuous hydrogenation of *CO to form CH4 rather than desorption to form CO. The effective regulation of the hydrogen bond network on the *COOH and *CO intermediates increases the selectivity of CO2 to CH4 conversion from 0.4% to 82%. In addition, this photocatalytic composite membrane system also shows good reaction stability, and still maintains a stable reduction product yield after continuous reaction for 30 days (8 hours per day). Brief Description of the Drawings

[0013] Figure 1 It is a graph of the yield of CO2 reduction products and CH4 selectivity of MPB / CN-g-CN photocatalyst under different proton source conditions.

[0014] Figure 2 It is a graph of the yield of CO2 reduction products and CH4 selectivity of MPB / CN-x-g-CN / ECE.

[0015] Figure 3 It is a graph of the yield of CO2 reduction products and CH4 selectivity of MPB / CN-g-CN / ECE photocatalytic membrane and the mixture of MPB / CN-g-CN+ECE. Detailed Description of the Invention

[0016] The following further describes the present invention in conjunction with the attached Figures 1-3 description: The material of a hydrogen-bond-rich network photocatalytic membrane of the present invention includes urea CO(NH2)2, potassium hydroxide KOH, methylammonium bromide MABr, lead bromide PbBr2, ethyl cellulose ECE, ethyl acetate C4H8O2, dimethyl sulfoxide DMSO, and isopropyl alcohol IPA.

[0017] The preparation method of the hydrogen-bond-rich network photocatalytic membrane material involved in the present invention is as follows: Dissolve a certain amount of CO(NH2)2 in a KOH solution, evaporate the water by heating to obtain a recrystallization mixture of CO(NH2)2 and KOH. Calcinate the obtained mixture in a muffle furnace at 400-800 °C for 4-10 h to obtain CN-g-C3N4 rich in cyano groups. Dissolve MABr and PbBr2 in DMSO to prepare a perovskite precursor solution, and ultrasonically disperse the CN-g-C3N4 obtained in step 1 in IPA for 1-4 h to prepare a CN-g-C3N4 dispersion. Drop a certain amount of the perovskite precursor solution into the IPA dispersion of CN-g-C3N4 and stir magnetically for 1-4 h. Collect the precipitate and wash it with IPA 5-10 times, and anneal it at 100-180 °C for 10-60 min after vacuum drying to obtain a MAPbBr3 / CN-g-C3N4 catalytic center. Dissolve ECE in C4H8O2 to prepare a membrane precursor solution, ultrasonically disperse the prepared MAPbBr3 / CN-g-C3N4 catalytic center in the ECE solution, and then pour it into a petri dish. After drying, a hydrogen-bond-rich network MAPbBr3 / CN-g-C3N4 / ECE photocatalytic membrane can be obtained. During the drying process, the hydrogen bond donors and acceptors in the MAPbBr3 / CN-g-C3N4 catalytic center and the ECE membrane material form a hydrogen bond network structure through self-assembly. Example 1

[0018] Dissolve 30 g of CO(NH2)2 in a KOH solution with a concentration of 2 mg / mL, and evaporate the water by heating to obtain a recrystallization mixture of CO(NH2)2 and KOH. Calcinate the obtained mixture in a muffle furnace at 500 °C for 5 h to obtain CN-g-C3N4 rich in cyano groups. Dissolve 20 mg of MABr and 50 mg of PbBr2 in 2 mL of DMSO to prepare a perovskite precursor solution. Weigh 50 mg of the prepared CN-g-C3N4 and disperse it in 5 mL of IPA, and ultrasonically treat it for 2 h to prepare a CN-g-C3N4 dispersion. Drop the perovskite precursor solution into the IPA dispersion of CN-g-C3N4 and stir magnetically for 2 h. Collect the precipitate and wash it 5 times with IPA, vacuum dry it, and anneal it at 150 °C for 10 min to obtain a MAPbBr3 / CN-g-C3N4 catalytic center. Dissolve 2 g of ECE in 50 mL of C4H8O2 to prepare a membrane precursor solution, and ultrasonically disperse the prepared MAPbBr3 / CN-g-C3N4 catalytic center in the ECE solution. Then take 2 mL of the ECE dispersion in a petri dish, and after drying, a MAPbBr3 / CN-g-C3N4 / ECE photocatalytic membrane rich in hydrogen bond networks (MPB / CN-g-CN / ECE-1) can be obtained. Example 2

[0019] Dissolve 50 g of CO(NH2)2 in a KOH solution with a concentration of 3 mg / mL, and evaporate the water by heating to obtain a recrystallization mixture of CO(NH2)2 and KOH. Calcinate the obtained mixture in a muffle furnace at 400 °C for 3 h to obtain CN-g-C3N4 rich in cyano groups. Dissolve 50 mg of MABr and 100 mg of PbBr2 in 20 mL of DMSO to prepare a perovskite precursor solution. Weigh 100 mg of the prepared CN-g-C3N4 and disperse it in 20 mL of IPA, and ultrasonically treat it for 2 h to prepare a CN-g-C3N4 dispersion. Drop the perovskite precursor solution into the IPA dispersion of CN-g-C3N4 and stir magnetically for 2 h. Collect the precipitate and wash it 5 times with IPA, vacuum dry it, and anneal it at 120 °C for 20 min to obtain a MAPbBr3 / CN-g-C3N4 catalytic center. Dissolve 5 g of ECE in 50 mL of C4H8O2 to prepare a membrane precursor solution, and ultrasonically disperse the prepared MAPbBr3 / CN-g-C3N4 catalytic center in the ECE solution. Then take 2 mL of the ECE dispersion in a petri dish, and after drying, a MAPbBr3 / CN-g-C3N4 / ECE photocatalytic membrane rich in hydrogen bond networks (MPB / CN-g-CN / ECE-2) can be obtained. Example 3

[0020] Dissolve 50 g of CO(NH2)2 in a KOH solution with a concentration of 3 mg / mL, and evaporate the water by heating to obtain a recrystallization mixture of CO(NH2)2 and KOH. Calcinate the obtained mixture in a muffle furnace at 500 °C for 5 h to obtain CN-g-C3N4 rich in cyano groups. Dissolve 50 mg of MABr and 200 mg of PbBr2 in 20 mL of DMSO to prepare a perovskite precursor solution. Weigh 200 mg of the prepared CN-g-C3N4 and disperse it in 20 mL of IPA, and ultrasonically treat it for 2 h to prepare a CN-g-C3N4 dispersion. Drop the perovskite precursor solution into the IPA dispersion of CN-g-C3N4 and magnetically stir for 2 h. Collect the precipitate and wash it 5 times with IPA, vacuum dry it, and anneal it at 150 °C for 20 min to obtain a MAPbBr3 / CN-g-C3N4 catalytic center. Dissolve 10 g of ECE in 50 mL of C4H8O2 to prepare a membrane precursor solution, and ultrasonically disperse the prepared MAPbBr3 / CN-g-C3N4 catalytic center in the ECE solution. Subsequently, take 2 mL of the ECE dispersion in a petri dish and dry it to obtain a MAPbBr3 / CN-g-C3N4 / ECE photocatalytic membrane rich in hydrogen bond networks (MPB / CN-g-CN / ECE-3). Comparative Example 1

[0021] Dissolve 50 g of CO(NH2)2 in a KOH solution with a concentration of 3 mg / mL, and evaporate the water by heating to obtain a recrystallization mixture of CO(NH2)2 and KOH. Calcinate the obtained mixture in a muffle furnace at 400 °C for 3 h to obtain CN-g-C3N4 rich in cyano groups. Dissolve 50 mg of MABr and 100 mg of PbBr2 in 20 mL of DMSO to prepare a perovskite precursor solution. Weigh 100 mg of the prepared CN-g-C3N4 and disperse it in 20 mL of IPA, and ultrasonically treat it for 2 h to prepare a CN-g-C3N4 dispersion. Drop the perovskite precursor solution into the IPA dispersion of CN-g-C3N4 and magnetically stir for 2 h. Collect the precipitate and wash it 5 times with IPA, vacuum dry it, and anneal it at 120 °C for 20 min to obtain a control sample of MAPbBr3 / CN-g-C3N4 catalyst powder (MPB / CN-g-CN). Comparative Example 2

[0022] 50 g of CO(NH2)2 was directly calcined in a muffle furnace at 400 °C for 3 h to obtain graphitic g-C3N4. 50 mg of MABr and 200 mg of PbBr2 were dissolved in 20 mL of DMSO to prepare a perovskite precursor solution. 200 mg of the prepared g-C3N4 was weighed and dispersed in 20 mL of IPA, and ultrasonic treatment was carried out for 2 h to prepare a g-C3N4 dispersion. The perovskite precursor solution was added dropwise to the IPA dispersion of g-C3N4, and magnetic stirring was carried out for 2 h. The precipitate was collected and washed 5 times with IPA, and after vacuum drying, it was annealed at 150 °C for 20 min to obtain a MAPbBr3 / g-C3N4 catalytic center. 10 g of ECE was dissolved in 50 mL of C4H8O2 to prepare a film precursor solution, and the prepared MAPbBr3 / g-C3N4 catalytic center was ultrasonically dispersed in the ECE solution. Subsequently, 2 mL of the ECE dispersion was taken in a petri dish, and after drying, the control sample MAPbBr3 / g-C3N4 / ECE photocatalytic film (MPB / g-CN / ECE) could be obtained. Comparative Example 3

[0023] 50 g of CO(NH2)2 was dissolved in a KOH solution with a concentration of 3 mg / mL, and the water was evaporated by heating to obtain a recrystallization mixture of CO(NH2)2 and KOH. The obtained mixture was calcined in a muffle furnace at 400 °C for 3 h to obtain CN-g-C3N4 rich in cyano groups. 50 mg of MABr and 100 mg of PbBr2 were dissolved in 20 mL of DMSO to prepare a perovskite precursor solution. 100 mg of the prepared CN-g-C3N4 was weighed and dispersed in 20 mL of IPA, and ultrasonic treatment was carried out for 2 h to prepare a CN-g-C3N4 dispersion. The perovskite precursor solution was added dropwise to the IPA dispersion of CN-g-C3N4, and magnetic stirring was carried out for 2 h. The precipitate was collected and washed 5 times with IPA, and after vacuum drying, it was annealed at 120 °C for 20 min to obtain MAPbBr3 / CN-g-C3N4 catalyst powder. Then, 0.5 g of MAPbBr3 / CN-g-C3N4 and 0.3 g of ECE powder were mixed in a mortar, and after grinding evenly, a mixture of MAPbBr3 / CN-g-C3N4 and ECE (MPB / CN-g-CN+ECE) could be prepared. In Examples 1-3, the hydrogen-bond-rich network photocatalytic film material obtained by the technical scheme of the present invention is composed of ethyl cellulose as the film-forming material, the MAPbBr3 / CN-g-C3N4 heterojunction as the catalytic center, the hydroxyl (-OH) groups in the ethyl cellulose molecule as the hydrogen-bond donors, and the -CN and -NH2 groups in the MAPbBr3 and CN-g-C3N4 molecules as the hydrogen-bond acceptors, which helps to improve the selectivity of photocatalytic CO2 reduction to prepare CH4. The specific analysis is as follows: Figure 1 It is the graph of the yields of CO2 reduction products and the selectivity of CH4 of the MPB / CN-g-CN photocatalyst under different proton source conditions. It can be seen from the graph that for Comparative Example 1, the method and components were used to obtain the MPB / CN-g-CN catalyst powder. Under the condition of no proton source, only a small amount of CO was produced as the reduction product and no CH4 was generated. This is because there is a lack of protons participating in the proton-coupled electron transfer process. When MPB / CN-g-CN uses acetonitrile / water and ethyl acetate / water as proton sources, the CO yields are increased to 7.22 and 8.15 μmol / g / h, and still no CH4 is generated. When water vapor is used as the proton source, the CO yield is 10.61 μmol / g / h, and a trace amount of CH4 is detected in the products, but its selectivity is only 0.4%. This is because the H2O decomposition process is slow and it is difficult to provide sufficient protons for the CO2 conversion. It should be noted that compared with the photocatalytic performance of MPB / CN-g-CN obtained in Comparative Example 1 under different proton sources, the yields of CO2 reduction products and the selectivity of CH4 of the MPB / g-CN / ECE target photocatalytic membrane obtained by the method and components of Example 1 are significantly improved. Among them, the CO and CH4 yields are 31.80 and 35.85 μmol / g / h respectively, and the CH4 selectivity is increased to 82%, proving that the rich hydrogen bond network structure in MPB / g-CN / ECE can provide sufficient protons for CO2 reduction.

[0024] Figure 2 It is the graph of regulating the number of hydrogen bond acceptor -CN groups on the surface of CN-g-CN by changing the concentration of the KOH alkaline solution and testing the yields of photocatalytic CO2 reduction products and the selectivity of CH4 of MPB / CN-x-g-CN / ECE. It can be seen from the graph that compared with the unmodified MPB / g-CN / ECE without cyano groups obtained by the method and components in Comparative Example 2, the yields of CO2 reduction products and the selectivity of CH4 of MPB / CN-g-CN / ECE will increase with the increase in the number of -CN groups. Among them, the CH4 yield and selectivity are increased from 21.91 μmol / g / h and 71% of the MPB / g-CN / ECE sample in Comparative Example 2 to 35.85 μmol / g / h and 82% of the MPB / CN-g-CN / ECE-2 target photocatalytic membrane in Example 2. This is mainly because the increased -CN groups in CN-g-CN will form more N···H-O hydrogen bonds with the ECE molecules. However, with the further increase in the number of -CN groups, the CH4 yield and selectivity of MPB / CN-g-CN / ECE are significantly reduced. This is because the catalyst particle size is too large, resulting in an uneven membrane structure, reducing the specific surface area and the number of active sites of the photocatalytic membrane.

[0025] Figure 3It is a graph showing the CO2 reduction product yields and CH4 selectivities of the MPB / CN-g-CN / ECE photocatalytic membrane and the MPB / CN-g-CN+ECE mixture. As can be seen from the graph, for the MPB / CN-g-CN+ECE mixture obtained in Comparative Example 3, although ECE can provide protons for CO2 reduction, the reduction product yield is relatively low, with the CO and CH4 yields being 23.55 and 5.31 μmol / g / h respectively, and the CH4 selectivity calculated to be 47%. With the formation of the ECE film and the hydrogen bond network, for the target MPB / CN-g-CN / ECE photocatalytic membrane obtained in Example 3, the CO and CH4 yields are increased to 31.80 and 35.85 μmol / g / h, respectively, where the CH4 yield is increased by 6.75 times compared to the MPB / CN-g-CN+ECE mixture, and the CH4 selectivity is increased to 82%. The results show that the highly interconnected hydrogen bond network promotes the selective formation of CH4 through efficient proton supply.

[0026] Based on the analysis and comparison of the above examples and comparative examples, it can be known that compared with H2O and ordinary proton sources, the hydrogen bond network designed in this patent, as a "proton supply station", is more easily oxidized by photo-generated holes, thereby providing more protons, promoting proton-coupled electron transfer, and improving the yield and selectivity of photocatalytic CO2 reduction to prepare CH4.

[0027] As described above, the above are only specific embodiments of the present invention, but the protection scope of the invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the invention.

Claims

1. A hydrogen-bond-rich network photocatalytic membrane, characterized in that: The photocatalytic membrane material is constructed with ethyl cellulose as the film-forming material, MAPbBr3 / CN-g-C3N4 heterojunction as the catalytic center, hydroxyl (-OH) groups in ethyl cellulose molecules as hydrogen bond donors, and -CN and -NH2 groups in MAPbBr3 and CN-g-C3N4 molecules as hydrogen bond acceptors. The material is prepared from urea CO(NH2)2, potassium hydroxide KOH, methylammonium bromide MABr, lead bromide PbBr2, ethyl cellulose ECE, ethyl acetate C4H8O2, dimethyl sulfoxide DMSO, and isopropyl alcohol IPA.

2. A method for preparing the hydrogen-bond-rich network photocatalytic membrane according to claim 1, characterized in that: The method is as follows: Step 1: Dissolve a certain amount of CO(NH2)2 in a KOH solution, evaporate the water by heating to obtain a recrystallization mixture of CO(NH2)2 and KOH, and calcine the obtained mixture in a muffle furnace at 400 - 800 °C for 4 - 10 h to obtain CN-g-C3N4 rich in cyano groups. Step 2: Dissolve MABr and PbBr2 in DMSO to prepare a perovskite precursor solution. Ultrasonically disperse the CN-g-C3N4 obtained in Step 1 in IPA for 1 - 4 h to prepare a CN-g-C3N4 dispersion; drop a certain amount of the perovskite precursor solution into the IPA dispersion of CN-g-C3N4 and stir magnetically for 1 - 4 h; collect the precipitate and wash it with IPA 5 - 10 times, and anneal it at 100 - 180 °C for 10 - 60 min after vacuum drying to obtain the MAPbBr3 / CN-g-C3N4 catalytic center. Step 3: Dissolve ECE in C4H8O2 to prepare a film precursor solution, and ultrasonically disperse the prepared MAPbBr3 / CN-g-C3N4 catalytic center in the ECE solution. Then take a certain amount of the ECE dispersion in a petri dish and dry it to obtain the MAPbBr3 / CN-g-C3N4 / ECE photocatalytic membrane rich in hydrogen bond networks; during the drying process, the hydrogen bond donors and acceptors in the MAPbBr3 / CN-g-C3N4 catalytic center and the ECE membrane material form a hydrogen bond network structure through self-assembly.

3. The preparation method of a hydrogen-bond-rich network photocatalytic membrane according to claim 2, characterized in that: In Step 1, the mass of CO(NH2)2 is 5 - 50 mg, and the concentration of the KOH solution is 0.5 - 3 mg / mL.

4. The preparation method of a hydrogen-bond-rich network photocatalytic membrane according to claim 2, wherein: In Step 2, the masses of MABr and PbBr2 are 10 - 60 mg and 50 - 200 mg respectively, the mass of CN-g-C3N4 is 10 - 200 mg, and the volumes of DMSO and IPA are 1 - 50 and 1 - 20 mL respectively.

5. The preparation method of a hydrogen-bond-rich network photocatalytic membrane according to claim 2, characterized in that: In Step 3, the mass of ECE is 0.5 - 10 g, the amount of C4H8O2 used is 5 - 100 mL, and the mass of the MAPbBr3 / CN-g-C3N4 catalyst is 0.01 - 5 g.

Images