Preparation method of photocatalytic hydrogel

Abstract

The invention provides a preparation method of photocatalytic hydrogel, belongs to the technical field of photocatalysis, and aims at solving the problems that traditional hydrogen production is high in energy consumption and pollution, and existing photocatalytic hydrogel is low in purity and unstable in performance. The method comprises the following steps: firstly, preparing seven precursors of CPDT-1, CPDT-2Br-SO3Na, PCT-SO3Na, Flu-2Br-SO3Na, PFT-SO3Na, PCBT-SO3Na and PFBT-SO3Na step by step, and carrying out nitrogen purging to prevent oxidation, acetone precipitation, recrystallization and Soxhlet extraction and purification in the process; the four active precursors are mixed with acrylic acid, pentaerythritol triallyl ether and (2, 4, 6-trimethylbenzoyl) diphenyl phosphine oxide respectively, the mixture is subjected to 365nm ultraviolet irradiation polymerization, and four photocatalytic hydrogels are prepared. The method has the advantages of mild conditions, controllable operation, high product purity and stable photocatalytic performance, and is suitable for hydrogen energy preparation and water pollution treatment.

Description

Technical Field

[0001] This invention relates to the field of photocatalysis technology, specifically to a method for preparing a photocatalytic hydrogel. Background Technology

[0002] In the field of hydrogen energy, hydrogen energy, as a clean and highly efficient energy carrier, has broad application prospects. However, the current mainstream hydrogen production methods (such as natural gas steam reforming and coal gasification) have the drawbacks of high energy consumption and high pollution, and cannot meet the industrial demand for "green hydrogen energy".

[0003] Photocatalytic hydrogen evolution technology, with its core advantages of being green and renewable, has become one of the key directions for solving the above problems. This technology uses sunlight to excite a photocatalyst, which absorbs photon energy to drive the splitting of water molecules to produce hydrogen and oxygen. It has the characteristics of wide energy source, environmental friendliness, mild reaction conditions, and high energy efficiency, and is expected to occupy a core position in the future hydrogen energy industry.

[0004] After years of technological development, photocatalysts have formed multiple systems, including metal-based photocatalysts (such as transition metal oxides, sulfides, and nitrides) and non-metal-based photocatalysts (such as black phosphorus, carbon quantum dots, and carbon nitride). In recent years, organic material-based photocatalysts (such as covalent organic polymers COP, conjugated microporous polymers CMP, covalent organic frameworks COF, and conjugated triazine frameworks CTF) have become a research hotspot. They have advantages such as strong tunability of molecular structure, clear elemental composition, and excellent hydrothermal stability, and the apparent quantum efficiency (AQY) of photocatalytic hydrogen evolution has increased from less than 1% to over 20%.

[0005] Photocatalytic hydrogels, as a combination of photocatalytic technology and hydrogel materials, have important application value in hydrogen production, water pollution control and other scenarios. However, existing preparation methods still have technical problems such as insufficient product purity, poor stability of photocatalytic performance and complex preparation process, which urgently need to be optimized and improved.

[0006] Therefore, a method for preparing photocatalytic hydrogels is proposed. Summary of the Invention

[0007] The present invention aims to solve the problems mentioned in the background art by providing a method for preparing photocatalytic hydrogels.

[0008] The specific technical solution is as follows: A method for preparing a photocatalytic hydrogel includes the following steps: (1) Preparation of CPDT-1: Cyclopentethiophene and tetrabutylammonium bromide were dissolved in dimethyl sulfoxide and placed in a Shrek bottle. Nitrogen gas was purged, and sodium hydroxide (NaOH) aqueous solution and 1,3-propane sulpholactone were added. The reaction was carried out at room temperature, and the reactants were poured into acetone to precipitate. After filtration, the precipitate was recrystallized with acetone and deionized water. After filtration, washing and drying, CPDT-1 was obtained. (2) Preparation of CPDT-2Br-SO3Na: CPDT-1, N,N-dimethylformamide (DMF) and deionized water were added to the reaction tube, wrapped with tin foil to protect from light, and purged with nitrogen. N-bromosuccinimide (NBS) was dissolved in N,N-dimethylformamide (DMF) and added dropwise to the reaction tube. The reaction was stirred at room temperature. The reactants were poured into acetone to precipitate, filtered, and recrystallized with acetone and deionized water. After filtration, washing and drying, CPDT-2Br-SO3Na was obtained. (3) Preparation of PCT-SO3Na: CPDT-2Br-SO3Na, dipinar thiophene-2,5-diboronate, and potassium carbonate (K2CO3) are prepared. 3） Tetraphenylphosphine palladium (Pd(PPh3)4), N,N-dimethylformamide (DMF) and deionized water were added to the reaction tube, purged with nitrogen, heated and reacted, the reactants were poured into acetone to precipitate, filtered and dried, extracted with n-hexane, acetone and deionized water by Soxhlet, and the filtrate was evaporated to dryness to obtain PCT-SO3Na. (4) Preparation of Fluo-2Br-SO3Na: 2,7-dibromofluorene, tetrabutylammonium bromide and DMSO were added to a Shrek bottle, purged with nitrogen, and then NaOH aqueous solution was added. 1,3-propanesulfonic acid lactone was dissolved in DMSO and added to the Shrek bottle. The reaction was carried out at room temperature. The reactants were poured into acetone to precipitate, filtered, and recrystallized with acetone and deionized water. The mixture was then filtered, washed, and dried to obtain Fluo-2Br-SO3Na. (5) Preparation of PFT-SO3Na: Fluo-2Br-SO3Na, thiophene-2,5-diboronic acid dipinate, potassium carbonate, tetraphenylphosphine palladium, N,N-dimethylformamide (DMF) and deionized water were added to the reaction tube, purged with nitrogen, heated and reacted, the reactants were poured into acetone to precipitate, filtered and dried, extracted with n-hexane, acetone and deionized water by Soxhlet extraction, the filtrate was evaporated by rotary evaporation and then poured into acetone to precipitate, filtered, washed and dried to obtain PFT-SO3Na; (6) Preparation of PCPT-SO3Na: CPDT-2Br-SO3Na, 4,7-diboronic acid pinacol-2,1,3-benzothiadiazole, potassium carbonate, tetraphenylphosphine palladium, N,N-dimethylformamide (DMF) and deionized water were added to the reaction tube, purged with nitrogen, heated and reacted, the reactants were poured into acetone to precipitate, filtered and dried, extracted with n-hexane, acetone and deionized water by Soxhlet extraction, the filtrate was evaporated by rotary evaporation and then poured into acetone to precipitate, filtered, washed and dried to obtain PCPT-SO3Na; (7) Preparation of PFBT-SO3Na: Fluo-2Br-SO3Na, 4,7-diboronic acid pinacol-2,1,3-benzothiadiazole, potassium carbonate, tetra-triphenylphosphine palladium, N,N-dimethylformamide (DMF) and deionized water were added to the reaction tube, purged with nitrogen, heated and reacted, the reactants were poured into acetone to precipitate, filtered and dried, extracted with n-hexane, acetone and deionized water by Soxhlet extraction, the filtrate was evaporated by rotary evaporation and then poured into acetone to precipitate, filtered, washed and dried to obtain PFBT-SO3Na; (8) Preparation of photocatalytic hydrogel: Take one of PCT-SO3Na, PFT-SO3Na, PCPT-SO3Na, and PFBT-SO3Na respectively, and stir with deionized water. Separately, stir acrylic acid with deionized water in the dark, add pentaerythritol triallyl ether and stir, then add diphenylphosphine oxide (or 2,4,6-trimethylbenzoyl) and stir, pour in the above precursor aqueous solution and stir, take the reaction solution and drop it into a petri dish, irradiate with ultraviolet light to obtain the corresponding photocatalytic hydrogel.

[0009] The preparation method of photocatalytic hydrogel using the above technical solution provides a complete photocatalytic hydrogel preparation process, covering the preparation steps of 7 precursors (CPDT-1, CPDT-2Br-SO3Na, PCT-SO3Na, Fluo-2Br-SO3Na, PFT-SO3Na, PCPT-SO3Na, PFBT-SO3Na) and 4 photocatalytic hydrogels (PCT photocatalytic hydrogel, PFT photocatalytic hydrogel, PCPT photocatalytic hydrogel, PFBT photocatalytic hydrogel). The proposed method involves purging the reaction system with nitrogen to remove oxygen and prevent it from interfering with the reaction and generating impurities. Multiple purification steps, including acetone precipitation, recrystallization, and Soxhlet extraction, are used to remove unreacted raw materials and byproducts from each precursor, improving the purity of all precursors. Finally, the purified precursors are polymerized with acrylic acid, pentaerythritol triallyl ether, and (2,4,6-trimethylbenzoyl)diphenylphosphine oxide under ultraviolet light irradiation. This process stably produces a hydrogel with acceptable purity and photocatalytic properties, suitable for hydrogen production and water pollution control applications. The overall process is controllable, providing a foundation for large-scale production.

[0010] In the above-mentioned method for preparing photocatalytic hydrogel, in step (1), the amount of cyclopentylthiophene is 500 mg, the amount of tetrabutylammonium bromide is 45 mg, the amount of DMSO is 15 mL, the nitrogen purging time is 30 min, the NaOH aqueous solution has a mass concentration of 40% and the amount is 1.12 g, the amount of 1,3-propanesulfonyl lactone is 855 mg, the room temperature reaction time is 3 h, the acetone precipitation time is 20 min, and the recrystallization time is 12 h.

[0011] By adopting the above technical solution, the amount of materials used in the preparation of CPDT-1 in step (1) (cyclopentylthiophene, tetrabutylammonium bromide, DMSO, 1,3-propanesulfonyl lactone) and the reaction parameters (NaOH aqueous solution concentration, room temperature reaction time, acetone precipitation time, recrystallization time) are limited. The specific material ratio can make cyclopentylthiophene and 1,3-propanesulfonyl lactone react fully and reduce the residue of unreacted raw materials; combined with acetone precipitation and recrystallization, the by-products and residual impurities generated by the reaction can be further removed, and the purity of CPDT-1 generated in step (1) can be improved; high-purity CPDT-1 can be used as a high-quality precursor for the preparation of CPDT-2Br-SO3Na in step (2), which can avoid the impact of excessive CPDT-1 impurities on the subsequent reaction efficiency and the purity of CPDT-2Br-SO3Na, and ensure the smooth progress of the subsequent preparation process.

[0012] In the above-mentioned method for preparing photocatalytic hydrogel, in step (2), the amount of CPDT-1 is 500 mg, the amount of N,N-dimethylformamide (DMF) is 6 mL, the amount of deionized water is 3 mL, the amount of NBS is 400 mg and dissolved in 6 mL of N,N-dimethylformamide (DMF), the reaction time is 3 h at room temperature, and the recrystallization time is 12 h.

[0013] Using the above technical solution, the amount of materials (CPDT-1, DMF, deionized water, NBS) and reaction time in the preparation of CPDT-2Br-SO3Na in step (2) are limited. The specific amount of materials can make CPDT-1 and NBS react fully and reduce the excess NBS residue; the operation of wrapping with tin foil to avoid light in step (2) can prevent the decomposition of photosensitive substances such as NBS to generate additional impurities; combined with the acetone precipitation and recrystallization operation, unreacted CPDT-1, NBS and by-products can be effectively removed, and the purity of CPDT-2Br-SO3Na generated in step (2) can be improved; high-purity CPDT-2Br-SO3Na can be used as a high-quality precursor for the preparation of PCT-SO3Na in step (3) and PCPT-SO3Na in step (6), which can avoid impurities from affecting the stability of subsequent polymerization reactions and ensure the purity of PCT-SO3Na and PCPT-SO3Na.

[0014] In the above-mentioned method for preparing photocatalytic hydrogel, in step (3), the amount of CPDT-2Br-SO3Na is 200mg, the amount of dipinaryl thiophene-2,5-diboronic acid is 110mg, the amount of potassium carbonate is 230mg, the amount of tetrakis(triphenylphosphine)palladium (Pd(PPh3)4) is 8mg, the amount of N,N-dimethylformamide (DMF) is 4mL, the amount of deionized water is 1.33mL, the nitrogen purging time is 30min, the heating reaction temperature is 90℃, the heating reaction time is 48h, and the extraction time of n-hexane, acetone, and deionized water during Soxhlet extraction is 8h.

[0015] Using the above technical solution, the amount of materials used in the preparation of PCT-SO3Na in step (3) (CPDT-2Br-SO3Na, dipinara thiophene-2,5-diboronate, potassium carbonate, tetraphenylphosphine palladium, DMF, deionized water) and reaction parameters (heating reaction temperature, heating reaction time, and Soxhlet extraction solvent) are limited. The specific material ratio and heating temperature and time can enable CPDT-2Br-SO3Na and dipinara thiophene-2,5-diboronate to fully undergo polymerization reaction, reducing the residue of unreacted intermediates; Soxhlet extraction (hexane, acetone, and deionized water extraction in sequence) can specifically remove oil-soluble impurities, water-soluble impurities and low-molecular-weight byproducts generated in the reaction, further improving the purity of PCT-SO3Na generated in step (3); high-purity PCT-SO3Na, as the precursor of PCT photocatalytic hydrogel in step (8), can avoid the influence of excessive PCT-SO3Na impurities on the photocatalytic performance of the hydrogel, providing a stable photocatalytic performance basis for PCT photocatalytic hydrogel.

[0016] In the above-mentioned method for preparing photocatalytic hydrogel, in step (4), the amount of 2,7-dibromofluorene is 503 mg, the amount of tetrabutylammonium bromide is 10.2 mg, the amount of DMSO is 10 mL, the nitrogen purging time is 30 min, the NaOH aqueous solution is 50% by mass and the amount is 1 mL, the amount of 1,3-propanesulfonic acid lactone is 468 mg and dissolved in 2.5 mL of DMSO, the reaction time at room temperature is 3 h, and the recrystallization time is 12 h.

[0017] Using the above technical solution, the amount of materials used in the preparation of Fluo-2Br-SO3Na in step (4) (2,7-dibromofluorene, tetrabutylammonium bromide, DMSO, 1,3-propanesulfonic acid lactone) and the reaction parameters (NaOH aqueous solution concentration, room temperature reaction time, recrystallization time) are limited. The specific material ratio can make 2,7-dibromofluorene and 1,3-propanesulfonic acid lactone react fully and reduce the residue of unreacted raw materials; combined with acetone precipitation and recrystallization, the by-products and residual impurities generated in the reaction can be removed, and the purity of Fluo-2Br-SO3Na generated in step (4) can be improved; high-purity Fluo-2Br-SO3Na can be used as a high-quality precursor for the preparation of PFT-SO3Na in step (5) and PFBT-SO3Na in step (7), which can avoid impurities from affecting the efficiency of subsequent polymerization reactions, ensure the purity of PFT-SO3Na and PFBT-SO3Na, and provide high-quality raw materials for subsequent hydrogel preparation.

[0018] In the above-mentioned method for preparing photocatalytic hydrogel, in step (5), the amount of Fluo-2Br-SO3Na is 300mg, the amount of thiophene-2,5-diboronic acid dipina ester is 165mg, the amount of potassium carbonate is 345mg, the amount of tetrakis(triphenylphosphine)palladium (Pd(PPh3)4) is 12mg, the amount of N,N-dimethylformamide DMF is 6mL, the amount of deionized water is 2mL, the nitrogen purging time is 30min, the heating reaction temperature is 90℃, the heating reaction time is 48h, and the extraction time of n-hexane, acetone, and deionized water during Soxhlet extraction is 8h.

[0019] Using the above technical solution, the amount of materials used in the preparation of PFT-SO3Na in step (5) (Fluo-2Br-SO3Na, dipinara thiophene-2,5-diboronate, potassium carbonate, tetraphenylphosphine palladium, DMF, deionized water) and the reaction parameters (heating reaction temperature, heating reaction time, and Soxhlet extraction solvent) are limited. The specific material ratio and heating conditions can fully polymerize Fluo-2Br-SO3Na and dipinara thiophene-2,5-diboronate, reducing the residue of unreacted substances; the operation of rotary evaporation of the filtrate after Soxhlet extraction and secondary acetone precipitation can further remove trace impurities and improve the purity of PFT-SO3Na generated in step (5); high-purity PFT-SO3Na, as the precursor of PFT photocatalytic hydrogel in step (8), can avoid impurities interfering with the polymerization process and photocatalytic performance of the hydrogel, and can ensure the stability of the photocatalytic performance of PFT photocatalytic hydrogel.

[0020] In the above-mentioned method for preparing photocatalytic hydrogel, in step (6), the amount of CPDT-2Br-SO3Na is 300mg, the amount of 4,7-diboronic acid pinacol-2,1,3-benzothiadiazole is 185mg, the amount of potassium carbonate is 345mg, the amount of tetrakis(triphenylphosphine)palladium is 12mg, the amount of N,N-dimethylformamide (DMF) is 6mL, the amount of deionized water is 2mL, the nitrogen purging time is 30min, the heating reaction temperature is 90℃, and the heating reaction time is 24h.

[0021] Using the above technical solution, the amount of materials used in the preparation of PCPT-SO3Na in step (6) (CPDT-2Br-SO3Na, 4,7-diboron pinacol-2,1,3-benzothiadiazole, potassium carbonate, tetraphenylphosphine palladium, DMF, deionized water) and reaction parameters (heating reaction temperature, heating reaction time) are limited. The specific material ratio and heating conditions can fully polymerize CPDT-2Br-SO3Na and 4,7-diboron pinacol-2,1,3-benzothiadiazole, avoiding insufficient or excessive reaction that generates impurities; combined with acetone precipitation, Soxhlet extraction and secondary acetone precipitation, unreacted raw materials and by-products can be effectively removed, improving the purity of PCPT-SO3Na generated in step (6); high-purity PCPT-SO3Na, as the precursor of PCPT photocatalytic hydrogel in step (8), can ensure the structural integrity and photocatalytic performance of PCPT photocatalytic hydrogel, avoiding impurities that cause a decrease in the photocatalytic efficiency of the hydrogel.

[0022] In the above-mentioned method for preparing photocatalytic hydrogel, in step (7), the amount of Fluo-2Br-SO3Na is 300mg, the amount of 4,7-diboronic acid pinacol-2,1,3-benzothiadiazole is 190mg, the amount of potassium carbonate (K2CO3) is 345mg, the amount of tetrakis(triphenylphosphine)palladium (Pd(PPh3)4) is 12mg, the amount of N,N-dimethylformamide (DMF) is 6mL, the amount of deionized water is 2mL, the nitrogen purging time is 30min, the heating reaction temperature is 90℃, and the heating reaction time is 24h.

[0023] Using the above technical solution, the amount of materials used in the preparation of PFBT-SO3Na in step (7) (Fluo-2Br-SO3Na, 4,7-diboron pinacol-2,1,3-benzothiadiazole, potassium carbonate, tetraphenylphosphine palladium, DMF, deionized water) and reaction parameters (heating reaction temperature, heating reaction time) are limited. The specific material ratio and heating conditions can fully polymerize Fluo-2Br-SO3Na and 4,7-diboron pinacol-2,1,3-benzothiadiazole, reducing the generation of unreacted intermediates and by-products; combined with acetone precipitation, Soxhlet extraction and secondary acetone precipitation, residual impurities can be removed, and the purity of PFBT-SO3Na generated in step (7) can be improved; high-purity PFBT-SO3Na, as the precursor of PFBT photocatalytic hydrogel in step (8), can ensure the polymerization uniformity and photocatalytic performance stability of PFBT photocatalytic hydrogel, and avoid impurities affecting the structure and function of hydrogel.

[0024] In the above-mentioned method for preparing photocatalytic hydrogel, in step (8), the amount of PCT-SO3Na / PFT-SO3Na / PCBT-SO3Na / PFBT-SO3Na is 2 mg, the amount of deionized water is 50 mL, and the stirring time is 30 min; the amount of acrylic acid is 10 g, the amount of deionized water is 50 mL, and the stirring time in the dark is 20 min; the amount of pentaerythritol triallyl ether is 50 mg, and the stirring time is 10 min; the amount of (2,4,6-trimethylbenzoyl)diphenylphosphine oxide is 50 mg, and the stirring time is 10 min; the ultraviolet light wavelength is 365 nm, and the irradiation time is 20 min.

[0025] Using the above technical solution, the material dosage (precursor, deionized water, acrylic acid, pentaerythritol triallyl ether, (2,4,6-trimethylbenzoyl)diphenylphosphine oxide) and reaction parameters (stirring time, ultraviolet wavelength, ultraviolet irradiation time) for the preparation of photocatalytic hydrogel in step (8) are limited. The specific dosage of the precursor and deionized water and the stirring time can make the precursor (PCT-SO3Na / PFT-SO3Na / PCBT-SO3Na / PFBT-SO3Na) fully dissolve and form a uniform aqueous solution; the specific ratio of acrylic acid and additives and the stirring time can form a prepolymer with uniform composition; after the prepolymer and the precursor aqueous solution are mixed evenly, the system can be fully solidified by ultraviolet irradiation of a specific wavelength, avoiding insufficient solidification that leads to uneven hydrogel structure; finally, a photocatalytic hydrogel (PCT / PFT / PCBT / PFBT photocatalytic hydrogel) with uniform structure and stable composition can be prepared. The uniform structure helps to improve the consistency and stability of the photocatalytic performance of the hydrogel.

[0026] In the above-mentioned method for preparing photocatalytic hydrogels, the drying process is carried out under vacuum at 60°C for 3-4 hours; the recrystallization process uses a mixed solvent of acetone and deionized water, and the rotary evaporation temperature of the filtrate after Soxhlet extraction is 60°C.

[0027] Using the above technical solution, the drying conditions (temperature and time), recrystallization solvent, and rotary evaporation temperature of the filtrate after Soxhlet extraction are limited during the preparation process. Vacuum drying at 60℃ can effectively remove moisture and volatile impurities from the product while avoiding thermal decomposition of precursors (CPDT-1, CPDT-2Br-SO3Na, etc.) and photocatalytic hydrogels, ensuring the dryness and purity of all products and preventing residual moisture from affecting subsequent reactions or hydrogel performance. Recrystallization with a mixed solvent of acetone and deionized water can specifically dissolve impurities, retain target precursors, and further improve the purity of each precursor. Rotary evaporation at a specific temperature can efficiently concentrate the filtrate after Soxhlet extraction, while avoiding the decomposition of effective components (such as PCT-SO3Na, PFT-SO3Na) in the filtrate, ensuring the recovery rate and purity of precursors, and providing high-quality raw materials for subsequent hydrogel preparation.

[0028] The present invention has the following beneficial effects: 1. Improved product purity and performance stability: Unreacted raw materials, byproducts and impurities in each precursor are removed through multi-step purification operations (acetone precipitation, recrystallization, Soxhlet extraction). At the same time, nitrogen purging is used to avoid the generation of oxidative impurities, ensuring the purity of photocatalytically active precursors (PCT-SO3Na, etc.). After the high-purity precursor is embedded in the hydrogel network, it can avoid the capture of photogenerated carriers by impurities, ensuring the stability of the photocatalytic performance of the hydrogel, while reducing the impact of impurities on the uniformity of the hydrogel structure and improving its mechanical and chemical stability.

[0029] 2. Mild preparation conditions and controllable operation: The precursor preparation is mainly carried out at room temperature or medium temperature, without the need for high temperature and high pressure equipment; the hydrogel solidification is achieved by 365nm ultraviolet light irradiation, which has low energy consumption and easy-to-control reaction rate; the whole process steps are clear (8 steps from primary intermediate to hydrogel), the material ratio and reaction parameters are clear, the repeatability is strong, the operation difficulty is reduced, and the large-scale preparation is facilitated, while avoiding the damage of extreme conditions to the precursor structure and photocatalytic performance.

[0030] 3. Expanding Applicability and Functional Diversity: Four photocatalytically active precursors (PCT-SO3Na, PFT-SO3Na, PCBT-SO3Na, and PFBT-SO3Na) and four corresponding photocatalytic hydrogels were prepared. The differences in molecular structure of the different precursors endow the hydrogels with different photoresponse characteristics and catalytic activities. Applicable products can be selected according to the needs of different application scenarios such as hydrogen production and water pollution control, thus expanding the scope of application of the technology. At the same time, the three-dimensional network structure of the hydrogel has both hydrophilicity and carrier function, which can be adapted to different reaction systems, further enhancing the functional diversity.

[0031] 4. Raw material utilization and reaction efficiency optimization: The material ratios in each step (such as the combination of catalyst, monomer and auxiliaries in precursor preparation) are optimized to promote full reaction of raw materials, reduce waste of unreacted raw materials, and improve raw material utilization. In the coupling reaction, using tetraphenylphosphine palladium as a catalyst and potassium carbonate as an alkaline medium can accelerate the reaction process, increase the precursor yield, and avoid over-reaction to generate non-target products, thus ensuring a balance between reaction efficiency and product quality. Attached Figure Description

[0032] Figure 1 The reaction equation for CPDT-1 and CPDT-2Br-SO3Na; Figure 2 The reaction equation for PCT-SO3Na; Figure 3 The reaction equation is for Fluo-2Br-SO3Na; Figure 4 The reaction equation for PFT-SO3Na; Figure 5 The reaction equation for PCBT-SO3Na; Figure 6 The reaction equation for PFBT-SO3Na; Figure 7 The ¹H NMR spectrum of CPDT-1; Figure 8 The ¹H NMR spectrum of CPDT-2Br-SO3Na; Figure 9 The ¹H NMR spectrum of Fluo-2Br-SO3Na is shown. Detailed Implementation

[0033] The following is in conjunction with the appendix Figure 1-9 The technical solution of the present invention will be further illustrated through specific embodiments.

[0034] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual images. They should not be construed as limiting the scope of this application. To better illustrate the embodiments of the present invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0035] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "inner," and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present application. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0036] In the description of this invention, unless otherwise explicitly specified and limited, the term "connection" or similar designation indicating a connection between components should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral part; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0037] Example 1: Preparation of CPDT-1 Accurately weigh 500 mg of cyclopentylthiophene (purity ≥98%) and 45 mg of tetrabutylammonium bromide (purity ≥99%), place them in a 100 mL Shrek flask, add 15 mL of DMSO (analytical grade), and stir magnetically until completely dissolved; connect the Shrek flask to a nitrogen source and purge with nitrogen at a flow rate of 100 mL / min for 30 min to purge air from the flask; then add 1.12 g of 40% NaOH aqueous solution (prepared with analytical grade NaOH) and 855 mg of 1,3-propanesulfonyl lactone (purity ≥98%) through a constant pressure dropping funnel, and continue mixing. The reaction was magnetically stirred at room temperature for 3 hours. After the reaction was completed, the reaction solution was slowly poured into 200 mL of acetone (analytical grade), and allowed to stand for 20 minutes to precipitate. The precipitate was then filtered through a Buchner funnel to obtain a pale yellow solid. The solid was transferred to a 50 mL beaker, and a mixture of 20 mL of acetone and 10 mL of deionized water was added. The mixture was heated to reflux to dissolve the solid, and then allowed to cool naturally to room temperature. The solid was allowed to stand for 12 hours to recrystallize. The solid was filtered again, and the filter cake was washed three times with deionized water. The filter cake was then dried in a vacuum drying oven at 60 °C for 4 hours to obtain CPDT-1 with a yield of approximately 82%.

[0038] Example 2: CPDT-2Br-SO 3 Preparation of Na Weigh 500 mg of CPDT-1 prepared in Example 1 and place it in a 50 mL reaction tube. Add 6 mL of LDMF (analytical grade) and 3 mL of deionized water, and stir magnetically until dissolved. Wrap the outer wall of the reaction tube tightly with aluminum foil to protect it from light. Connect the reaction tube to a nitrogen source and purge with nitrogen for 30 min (flow rate 80 mL / min). Separately, take 400 mg of NBS (purity ≥99%), dissolve it in 6 mL of LDMF, and add the solution dropwise to the reaction tube using a syringe (dropping rate 1 drop / second). After the addition is complete, stir magnetically at room temperature for 3 h. After the reaction is complete, pour the reaction solution into 150 mL of acetone, allow it to stand to precipitate, and filter to obtain a pale yellow solid. Recrystallize the solid with a mixture of 15 mL of acetone and 10 mL of deionized water for 12 h. After filtration, wash the filter cake twice with acetone and dry it under vacuum at 60 °C for 3 h to obtain CPDT-2Br-SO. 3 Na, yield is approximately 78%.

[0039] Example 3: PCT-SO 3 Preparation of Na Weigh 200 mg of CPDT-2Br-SO3Na prepared in Example 2, 110 mg of dipinaryl thiophene-2,5-diboronate (purity ≥98%), 230 mg of potassium carbonate (analytical grade), and 8 mg of tetrakis(triphenylphosphine)palladium (purity ≥99%), and place them in a 50 mL reaction tube. Add 4 mL of LDMF and 1.33 mL of deionized water, and stir magnetically until homogeneous. Purge with nitrogen for 30 min (flow rate 80 mL / min). Place the reaction tube in a 90 °C oil bath and stir magnetically for 48 h. After the reaction is complete, pour the reaction solution into 150 mL of acetone and filter to obtain a black solid. Place the solid in a Soxhlet extractor and extract with n-hexane (analytical grade), acetone, and deionized water for 8 h each. Collect the filtrates after each extraction and evaporate to dryness at 60 °C using a rotary evaporator to obtain PCT-SO3Na with a yield of approximately 75%.

[0040] Example 4: Preparation of Fluo-2Br-SO3Na Accurately weigh 503 mg of 2,7-dibromofluorene (purity ≥98%) and 10.2 mg of tetrabutylammonium bromide, place them in a 100 mL Shrek flask, add 10 mL of DMSO, and stir magnetically until dissolved; purge with nitrogen for 30 min (flow rate 100 mL / min); add 1 mL of 50% NaOH aqueous solution and stir magnetically for 5 min; separately, dissolve 468 mg of 1,3-propanesulfonic acid lactone in 2.5 mL of DMSO, add this solution to the Shrek flask, and react magnetically at room temperature for 3 h; after the reaction is complete, pour the reaction solution into 200 mL of acetone, precipitate, and filter to obtain a white solid; recrystallize with a mixture of 15 mL of acetone and 10 mL of deionized water for 12 h, filter, and dry under vacuum at 60 °C for 3 h to obtain Fluo-2Br-SO3Na, with a yield of approximately 80%.

[0041] Example 5: Preparation of PFT-SO3Na Weigh 300 mg of Fluo-2Br-SO3Na prepared in Example 4, 165 mg of dipinarthiophene-2,5-diboronate, 345 mg of potassium carbonate, and 12 mg of tetrakis(triphenylphosphine)palladium, and place them in a 50 mL reaction tube. Add 6 mL of LDMF and 2 mL of deionized water, and stir magnetically until homogeneous. Purge with nitrogen for 30 min. Place the reaction tube in a 90 °C oil bath and keep it at that temperature for 48 h. After the reaction is complete, pour the reaction solution into 150 mL of acetone, filter and dry to obtain a black solid. Extract with n-hexane, acetone and deionized water sequentially for 8 h each using a Soxhlet extractor. Collect the filtrate, concentrate it to 5 mL by rotary evaporation, pour the concentrate into 50 mL of acetone to precipitate, filter and dry under vacuum at 60 °C for 4 h to obtain PFT-SO3Na, with a yield of approximately 72%.

[0042] Example 6: Preparation of PCPT-SO3Na Weigh 300 mg of CPDT-2Br-SO3Na prepared in Example 2, 185 mg of 4,7-diboronic acid pinacol-2,1,3-benzothiadiazole (purity ≥98%), 345 mg of potassium carbonate, and 12 mg of tetrakis(triphenylphosphine) palladium, and place them in a 50 mL reaction tube. Add 6 mL of LDMF and 2 mL of deionized water, and stir magnetically until homogeneous. Purge with nitrogen for 30 min. Place the reaction tube in a 90 °C oil bath and keep it at that temperature for 24 h. After the reaction is complete, follow the post-treatment method in Example 5 (acetone precipitation, Soxhlet extraction, rotary evaporation concentration, secondary precipitation, and drying) to obtain PCDT-SO3Na with a yield of approximately 70%.

[0043] Example 7: Preparation of PFBT-SO3Na Weigh 300 mg of Fluo-2Br-SO3Na prepared in Example 4, 190 mg of 4,7-diboronic acid pinacol-2,1,3-benzothiadiazole, 345 mg of potassium carbonate, and 12 mg of tetrakis(triphenylphosphine)palladium into a 50 mL reaction tube, add 6 mL of LDMF and 2 mL of deionized water, and stir magnetically until homogeneous; purge with nitrogen for 30 min; place the reaction tube in a 90 °C oil bath and keep it at that temperature for 24 h; after the reaction is complete, follow the post-processing method in Example 5 to obtain PFBT-SO3Na with a yield of approximately 68%.

[0044] Example 8: Preparation of Four Types of Photocatalytic Hydrogels PCT photocatalytic hydrogel: Take 2 mg of PCT-SO3Na prepared in Example 3, add 50 mL of deionized water, and stir magnetically for 30 min until dissolved; take 10 g of acrylic acid (analytical grade), add 50 mL of deionized water, and stir magnetically for 20 min under light-protected conditions; add 50 mg of pentaerythritol triallyl ether (purity ≥98%), and stir for 10 min; then add 50 mg of (2,4,6-trimethylbenzoyl)diphenylphosphine oxide (purity ≥98%), and stir for 10 min; pour the prepolymer solution into the PCT-SO3Na aqueous solution, and stir for 10 min; drop the mixture into a 5 cm diameter petri dish (liquid layer thickness about 2 mm), and irradiate with a 365 nm ultraviolet lamp (power 10 W) for 20 min to obtain a transparent PCT photocatalytic hydrogel.

[0045] PFT photocatalytic hydrogel: Using PFT-SO3Na prepared in Example 5 as a precursor, the PFT photocatalytic hydrogel was obtained by following the above steps.

[0046] PCBT photocatalytic hydrogel: Using PCBT-SO3Na prepared in Example 6 as a precursor, the PCBT photocatalytic hydrogel was obtained by following the above steps.

[0047] PFBT photocatalytic hydrogel: Using PFBT-SO3Na prepared in Example 7 as a precursor, the PFBT photocatalytic hydrogel was obtained by following the above steps.

[0048] To predict and optimize the photocatalytic hydrogen production efficiency of hydrogels under specific light conditions, this application proposes a performance optimization equation for photocatalytic hydrogels, as follows: ; in: η: Actual photocatalytic hydrogen production efficiency (%); η0: Ideal maximum hydrogen production efficiency (%), determined by the intrinsic structure of the precursor; [C]: Effective concentration of the precursor in the current hydrogel (mol / L); [C]0: Reference concentration of the precursor under completely uniform dispersion (mol / L); E a Activation energy of photogenerated carriers (eV); k B Boltzmann constant; T: Reaction temperature (K); α: Absorption coefficient of hydrogel for a specific wavelength of light (mm) -1 ); d: Hydrogel thickness (mm); Φ(I0,λ): The intensity- and wavelength-dependent quantum efficiency function, defined as: ; I0: Incident light intensity (mW / cm²); λ: Incident light wavelength (nm); K: The saturation constant unique to the material.

[0049] Equation derivation process: This equation integrates the following physical and chemical mechanisms: 1. Concentration effect: It reflects the uniformity of the precursor dispersion in the hydrogel, and affects light absorption and reaction sites; 2. Arrhenius term: Describe the effect of temperature on carrier transitions; 3. Light absorption term: 1-e -αd This indicates the depth effect of light penetration through the hydrogel; 4. Light intensity and wavelength response terms: Φ(I0,λ) introduces a saturation function to simulate the synergistic effect of light intensity and wavelength, avoiding efficiency saturation under excessively high light intensity.

[0050] For example, given: η0 = 20%, [C] / [C]0 = 0.9, E a=0.5eV, T=298K, α=0.2mm -1 ,d=2mm, I0 = 100mW / cm 2 Given λ=365nm and K=5000, we can calculate: ; ; The results are in good agreement with the actual measured values ​​(e.g., the hydrogen production efficiency of the PCT hydrogel in the examples is about 7.5%).

[0051] Technical effects: Highly predictive: Hydrogen production efficiency can be predicted by adjusting parameters such as precursor concentration, hydrogel thickness, and light conditions; Optimization guidance: guides the selection of experimental conditions (such as optimal thickness, light intensity, wavelength); Quality control: used to evaluate the performance consistency of different batches of hydrogels; Innovative protection: Combining material structure (η0,K) with process parameters ([C],d) can improve the accuracy of prediction results.

[0052] The working principle of this equation is as follows: Increased precursor purity → Improved hydrogel uniformity → [C] / [C]0 → η↑; Optimize lighting conditions → I0,λ → Φ(I0,λ) → η↑; Hydrogel thickness control → d → light absorption term → η↑; Temperature control → T → Activation energy term → η↑.

[0053] In summary, this preparation method combines photocatalytic performance with the function of a hydrogel carrier through a stepwise process of "synthesizing a high-purity photocatalytic precursor → constructing a photoresponsive polymerization system → solidifying to form a functional hydrogel". Specifically, it consists of two parts: the principle of precursor preparation and the principle of hydrogel polymerization and photocatalysis. (I) Principle of precursor preparation 1. Intermediate Synthesis and Directed Reaction Control: Using cyclopentylthiophene and 2,7-dibromofluorene as starting materials, a substitution reaction was completed with the assistance of tetrabutylammonium bromide by introducing 1,3-propanesulfonyl lactone / 1,3-propanesulfonic acid lactone (to construct a hydrophilic sulfonic acid group and improve subsequent water compatibility) to generate CPDT-1 and Fluo-2Br-. The primary intermediates, such as SO3Na, were then brominated using N-bromosuccinimide (NBS) to introduce reactive sites and provide conditions for subsequent coupling reactions. During the bromination process, the reaction tube was wrapped with tin foil to protect it from light (to prevent the decomposition of photosensitive reagents such as NBS and avoid the generation of non-target impurities). Finally, using tetraphenylphosphine palladium as a catalyst and potassium carbonate as an alkaline medium, the brominated intermediates were coupled with dipinate thiophene-2,5-diboronate / pinacol-4,7-diboronate alcohol-2,1,3-benzothiadiazole to construct a conjugated molecular structure, providing a basis for subsequent photocatalytic performance, resulting in four photocatalytically active precursors: PCT-SO3Na, PFT-SO3Na, PCPT-SO3Na, and PFBT-SO3Na.

[0054] 2. Reaction Environment and Purification Control: Nitrogen purging was used in all precursor preparation steps (to remove oxygen from the system and prevent oxygen from reacting with the catalyst and active intermediates to generate oxidative impurities, ensuring the reaction proceeds in a directed manner); at the same time, multi-step purification was achieved through acetone precipitation (using the difference in solubility of the target precursor and impurities in acetone to initially separate impurities), acetone-deionized water recrystallization (to further dissolve residual small molecule impurities and purify the target product), and Soxhlet extraction (using n-hexane, acetone, and deionized water sequentially to selectively remove oil-soluble, polar impurities and low-molecular-weight byproducts) to ensure the purity of the precursor.

[0055] (II) Principles of hydrogel polymerization and photocatalysis 1. Hydrogel Network Construction: Acrylic acid was used as the polymerizing monomer (providing the basic framework for crosslinking polymerization), pentaerythritol triallyl ether was used as the crosslinking agent (to construct a three-dimensional network structure and improve the mechanical stability of the hydrogel), and (2,4,6-trimethylbenzoyl)diphenylphosphine oxide was used as the photoinitiator (to generate free radicals under 365nm ultraviolet light irradiation and initiate the polymerization reaction). After the photocatalytically active precursor (PCT-SO3Na, etc.) was uniformly mixed with the above monomer-auxiliary system, free radical polymerization was triggered by ultraviolet light irradiation, so that the acrylic acid monomer and the crosslinking agent crosslinked to form a three-dimensional network, and the precursor was uniformly embedded in the network to form a photocatalytic hydrogel.

[0056] 2. Photocatalytic function: The precursors (such as PCT-SO3Na) in the hydrogel have a conjugated molecular structure, which can absorb photon energy and generate photogenerated charge carriers. After the charge carriers migrate to the surface of the hydrogel, they can react with water molecules to achieve photocatalytic hydrogen evolution or pollutant degradation in water pollution control. At the same time, the three-dimensional network structure of the hydrogel can fix the precursor (preventing its loss) and increase the contact area between water and reactants, ensuring the stable performance of the photocatalytic function.

[0057] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a photocatalytic hydrogel, characterized by, Includes the following steps: (1) Preparation of CPDT-1: Cyclopentethiophene and tetrabutylammonium bromide were dissolved in dimethyl sulfoxide and placed in a Shrek bottle. Nitrogen gas was purged, and NaOH aqueous solution and 1,3-propane sulpholactone were added. The reaction was carried out at room temperature. The reactants were poured into acetone to precipitate, filtered, and recrystallized with acetone and deionized water. The mixture was filtered again, washed, and dried to obtain CPDT-1. (2) Preparation of CPDT-2Br-SO3Na: CPDT-1, N,N-dimethylformamide and deionized water were added to the reaction tube, wrapped with tin foil to protect from light, and purged with nitrogen. N-bromosuccinimide was dissolved in N,N-dimethylformamide and added dropwise to the reaction tube. The reaction was stirred at room temperature. The reactants were poured into acetone to precipitate, filtered, and recrystallized with acetone and deionized water. The mixture was then filtered, washed, and dried to obtain CPDT-2Br-SO3Na. (3) Preparation of PCT-SO3Na: CPDT-2Br-SO3Na, dipinar thiophene-2,5-diboronic acid, potassium carbonate, tetraphenylphosphine palladium, N,N-dimethylformamide and deionized water were added to the reaction tube, purged with nitrogen, heated and reacted, the reactants were poured into acetone to precipitate, filtered and dried, extracted with n-hexane, acetone and deionized water by Soxhlet extraction, and the filtrate was evaporated to dryness to obtain PCT-SO3Na; (4) Preparation of Fluo-2Br-SO3Na: 2,7-dibromofluorene, tetrabutylammonium bromide and DMSO were added to a Shrek bottle, purged with nitrogen, and then NaOH aqueous solution was added. 1,3-propanesulfonic acid lactone was dissolved in DMSO and added to the Shrek bottle. The reaction was carried out at room temperature. The reactants were poured into acetone to precipitate, filtered, and recrystallized with acetone and deionized water. The mixture was then filtered, washed, and dried to obtain Fluo-2Br-SO3Na. (5) Preparation of PFT-SO3Na: Fluo-2Br-SO3Na, thiophene-2,5-diboronic acid dipinarate, potassium carbonate, tetraphenylphosphine palladium, N,N-dimethylformamide and deionized water were added to the reaction tube, purged with nitrogen, heated and reacted, the reactants were poured into acetone to precipitate, filtered and dried, extracted with n-hexane, acetone and deionized water by Soxhlet extraction, the filtrate was evaporated and poured into acetone to precipitate, filtered, washed and dried to obtain PFT-SO3Na; (6) Preparation of PCPT-SO3Na: CPDT-2Br-SO3Na, 4,7-diboronic acid pinacol-2,1,3-benzothiadiazole, potassium carbonate, tetra-triphenylphosphine palladium, N,N-dimethylformamide and deionized water were added to the reaction tube, purged with nitrogen, heated and reacted, the reactants were poured into acetone to precipitate, filtered and dried, extracted with n-hexane, acetone and deionized water by Soxhlet extraction, the filtrate was evaporated by rotary evaporation and then poured into acetone to precipitate, filtered, washed and dried to obtain PCPT-SO3Na; (7) Preparation of PFBT-SO3Na: Fluo-2Br-SO3Na, 4,7-diboronic acid pinacol-2,1,3-benzothiadiazole, potassium carbonate, tetra-triphenylphosphine palladium, N,N-dimethylformamide and deionized water were added to the reaction tube, purged with nitrogen, heated and reacted, the reactants were poured into acetone to precipitate, filtered and dried, extracted with n-hexane, acetone and deionized water by Soxhlet extraction, the filtrate was evaporated by rotary evaporation and then poured into acetone to precipitate, filtered, washed and dried to obtain PFBT-SO3Na; (8) Preparation of photocatalytic hydrogel: Take one of PCT-SO3Na, PFT-SO3Na, PCBT-SO3Na and PFBT-SO3Na respectively, stir with deionized water, and stir acrylic acid with deionized water in the dark. Add pentaerythritol triallyl ether and stir, then add diphenylphosphine oxide and stir. Pour in the above precursor aqueous solution and stir. Take the reaction solution and drop it into a petri dish. Irradiate with ultraviolet light to obtain the corresponding photocatalytic hydrogel.

2. The method for preparing the photocatalytic hydrogel according to claim 1, characterized in that, In step (1), the amount of cyclopentylthiophene used is 500 mg, the amount of tetrabutylammonium bromide used is 45 mg, the amount of DMSO used is 15 mL, the nitrogen purging time is 30 min, the NaOH aqueous solution has a mass concentration of 40% and the amount used is 1.12 g, the amount of 1,3-propanesulfonyl lactone used is 855 mg, the reaction time at room temperature is 3 h, the acetone precipitation time is 20 min, and the recrystallization time is 12 h.

3. The method of claim 1, wherein the photocatalytic hydrogel is prepared by the steps of: In step (2), the amount of CPDT-1 used is 500 mg, the amount of N,N-dimethylformamide is 6 mL, the amount of deionized water is 3 mL, the amount of NBS is 400 mg and dissolved in 6 mL of N,N-dimethylformamide, the reaction time is 3 h at room temperature, and the recrystallization time is 12 h.

4. The method of claim 1, wherein the photocatalytic hydrogel is prepared by the steps of: In step (3), the amount of CPDT-2Br-SO3Na used is 200mg, the amount of thiophene-2,5-diboronic acid dipinarate used is 110mg, the amount of K2CO3 used is 230mg, the amount of tetrakis(triphenylphosphine)palladium used is 8mg, the amount of N,N-dimethylformamide used is 4mL, the amount of deionized water used is 1.33mL, the nitrogen purging time is 30min, the heating reaction temperature is 90℃, the heating reaction time is 48h, and the extraction time of n-hexane, acetone, and deionized water during Soxhlet extraction is 8h.

5. The method for preparing the photocatalytic hydrogel according to claim 1, characterized in that, In step (4), the amount of 2,7-dibromofluorene is 503 mg, the amount of tetrabutylammonium bromide is 10.2 mg, the amount of DMSO is 10 mL, the nitrogen purging time is 30 min, the NaOH aqueous solution is 50% by mass and the amount is 1 mL, the amount of 1,3-propanesulfonic acid lactone is 468 mg and dissolved in 2.5 mL of DMSO, the reaction time at room temperature is 3 h, and the recrystallization time is 12 h.

6. The method of claim 1, wherein the photocatalytic hydrogel is prepared by the steps of: In step (5), the amount of Fluo-2Br-SO3Na used is 300 mg, the amount of thiophene-2,5-diboronic acid dipinate is 165 mg, the amount of potassium carbonate is 345 mg, the amount of tetrakis(triphenylphosphine)palladium is 12 mg, the amount of N,N-dimethylformamide (DMF) is 6 mL, the amount of deionized water is 2 mL, the nitrogen purging time is 30 min, the heating reaction temperature is 90 °C, the heating reaction time is 48 h, and the extraction time of n-hexane, acetone, and deionized water during Soxhlet extraction is 8 h each.

7. The method for preparing the photocatalytic hydrogel according to claim 1, characterized in that, In step (6), the amount of CPDT-2Br-SO3Na is 300 mg, the amount of 4,7-diboronic acid pinacol-2,1,3-benzothiadiazole is 185 mg, the amount of potassium carbonate is 345 mg, the amount of tetra-triphenylphosphine palladium is 12 mg, the amount of N,N-dimethylformamide is 6 mL, the amount of deionized water is 2 mL, the nitrogen purging time is 30 min, the heating reaction temperature is 90 °C, and the heating reaction time is 24 h.

8. The method for preparing the photocatalytic hydrogel according to claim 1, characterized in that, In step (7), the amount of Fluo-2Br-SO3Na used is 300mg, the amount of 4,7-diboronic acid pinacol-2,1,3-benzothiadiazole used is 190mg, the amount of potassium carbonate used is 345mg, the amount of tetra-triphenylphosphine palladium used is 12mg, the amount of N,N-dimethylformamide used is 6mL, the amount of deionized water used is 2mL, the nitrogen purging time is 30min, the heating reaction temperature is 90℃, and the heating reaction time is 24h.

9. The method for preparing the photocatalytic hydrogel according to claim 1, characterized in that, In step (8), the amount of PCT-SO3Na / PFT-SO3Na / PCBT-SO3Na / PFBT-SO3Na used is 2 mg, the amount of deionized water used is 50 mL, and the stirring time is 30 min; the amount of acrylic acid used is 10 g, the amount of deionized water used is 50 mL, and the stirring time in the dark is 20 min; the amount of pentaerythritol triallyl ether used is 50 mg, and the stirring time is 10 min; the amount of diphenylphosphine oxide used is 50 mg, and the stirring time is 10 min; the ultraviolet light wavelength is 365 nm, and the irradiation time is 20 min.

10. The method for preparing the photocatalytic hydrogel according to any one of claims 1-9, characterized in that, All drying processes were carried out under vacuum at 60°C for 3–4 hours. All recrystallization processes used a mixed solvent of acetone and deionized water, and the rotary evaporation temperature of the filtrate after Soxhlet extraction was 60°C.

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