A Preparation Method of a Photocatalytic Hydrogen-Evolving Hydrogel

Abstract

The present invention provides a method for preparing a photocatalytic hydrogen-evolving hydrogel. The method for preparing the photocatalytic hydrogen-evolving hydrogel is to blend a highly efficient oligomeric acceptor TDY-α or TDY-β with a donor material, first prepare a suspension of nanoparticles, then add a hydrogel precursor material, and after mixing evenly, add a gelation-promoting material to obtain a hydrogel solution, which can be used directly or further post-treated according to actual needs to obtain a hydrogel film, hydrogel microspheres, dry hydrogel microspheres, etc. The photocatalytic hydrogen-evolving hydrogel loaded with organic photocatalyst nanoparticles prepared by the technical solution provided by the present invention has good hydrogen evolution efficiency, and can be further prepared into a hydrogel film, microspheres, etc. according to actual needs, which can effectively reduce secondary pollution, facilitate recycling and reuse, and broaden the application scenarios of photocatalytic hydrogels.

Description

Technical Field

[0001] The present invention belongs to the technical field of photocatalytic materials, and particularly relates to a preparation method of a photocatalytic hydrogen evolution hydrogel. Background Art

[0002] Hydrogen energy is a clean and highly efficient energy source. However, the current main methods for hydrogen production, such as natural gas steam reforming and coal gasification, produce hydrogen accompanied by high energy consumption and environmental pollution problems, and are not truly "green hydrogen energy". The photocatalytic hydrogen evolution technology has attracted much attention as a green and renewable hydrogen production method. This technology can use sunlight to excite the catalyst, enabling it to absorb photon energy and promote the splitting of water molecules to produce hydrogen and oxygen. It has the advantages of a wide range of energy sources, environmental friendliness, mild reaction conditions, high energy efficiency, and is expected to become an important part of the future hydrogen energy industry.

[0003] After decades of development, a variety of photocatalysts have been developed, including metal-based photocatalysts (transition metal oxides, sulfides, nitrides, etc.) and non-metal-based photocatalysts (black phosphorus, carbon quantum dots, carbon nitride, etc.). In recent years, organic material-based photocatalysts have received continuous attention and research, such as covalent organic polymers COP, conjugated microporous polymers CMP, covalent organic frameworks COF, conjugated triazine frameworks CTF, etc. The advantages of organic photocatalysts lie in their rich and adjustable molecular structures, clear elemental compositions, good hydrothermal stabilities, etc. Currently, the apparent quantum efficiency (AQY) of photocatalytic hydrogen evolution based on organic photocatalysts has increased from less than 1% at the beginning to more than 20% today.

[0004] Research shows that bulk heterojunction nanoparticles (BHJ-NPs) based on organic semiconductor molecules can greatly improve the efficiency of photocatalytic hydrogen evolution. When organic acceptor molecules with large conjugated planes and ADA’DA-type molecular structures are matched with organic donor molecules, they have a wide light absorption range, good light absorption rate, and exhibit good potential for photocatalytic hydrogen evolution, but there are few related reports currently. At the same time, hydrogels with three-dimensional network microporous structures have characteristics such as high specific surface area, high adsorption capacity, and good environmental compatibility. Combining organic acceptor molecules with hydrogel technology to prepare hydrogels loaded with organic photocatalysts is a promising idea for improving photocatalytic hydrogen evolution technology. Summary of the Invention

[0005] The purpose of the present invention is to provide a preparation method of a photocatalytic hydrogen evolution hydrogel. By using efficient organic photovoltaic acceptor molecules and organic donor molecules to prepare bulk heterojunction nanoparticles, and then loading them into the hydrogel, the photocatalytic hydrogen evolution efficiency and application applicability are effectively improved.

[0006] To achieve the above object, the technical solution adopted by the present invention is to provide a method for preparing a photocatalytic hydrogen-evolving hydrogel, and the preparation method includes the following steps:

[0007] Step S1, dissolving the high-efficiency oligomer acceptor material TDY-α or TDY-β and the donor material in an organic solvent, heating to completely dissolve them to form a good donor-acceptor blend solution;

[0008] Step S2, slowly dropping the donor-acceptor blend solution into the TEBS aqueous solution, and maintaining continuous ultrasonic waves during the dropping process to obtain a good microemulsion;

[0009] Step S3, drying the microemulsion under reduced pressure to remove the residual organic solvent in the system to obtain a nanoparticle suspension;

[0010] Step S4, adding a hydrogel precursor material to the nanoparticle suspension and stirring well;

[0011] Step S5, adding a gelation-promoting material solution to obtain a hydrogel solution loaded with organic photocatalyst nanoparticles.

[0012] In one embodiment, the mass ratio of the high-efficiency oligomer acceptor material TDY-α or TDY-β to the donor material is 1:1 to 1:4.

[0013] In one embodiment, the donor material is one or more of PM6, D18, and PTQ10, and the organic solvent is a low-boiling organic solvent.

[0014] In one embodiment, the organic solvent is chloroform.

[0015] In one embodiment, the concentration of the donor-acceptor blend solution is 0.1 to 20 mg / mL. This concentration will affect the particle size of the prepared nanoparticles.

[0016] In one embodiment, the concentration of the TEBS aqueous solution is 0.1 to 10 mg / mL. This concentration will affect the wall thickness of the prepared nanoparticles, and affect their light absorption rate, photocatalytic efficiency, etc.

[0017] In one embodiment, in step 2, the ultrasonic treatment method uses an internal ultrasonic vibration rod or an external ultrasonic cleaner, and the ultrasonic intensity is 200 to 1000 W. This intensity will affect the particle size of the prepared nanoparticles, and thus affect the photocatalytic efficiency, etc.

[0018] In one embodiment, in step 4, the concentration of the prepared solution is 1 to 30 mg / mL.

[0019] In one embodiment, the hydrogel precursor material is sodium alginate.

[0020] In one embodiment, the gelation-promoting material is one or more of calcium chloride, chitosan, and gelatin.

[0021] In one embodiment, the preparation method further includes:

[0022] Step S6, obtaining bulk hydrogel, hydrogel film, hydrogel microspheres, etc. after treating the hydrogel solution.

[0023] 1. High-efficiency photocatalytic hydrogen evolution efficiency: In the present invention, high-efficiency oligomer acceptor materials TDY-α or TDY-β are matched with donor materials to prepare nanoparticles with TEBS as the wall layer, exerting their excellent light absorption rate. The photocatalytic hydrogen evolution efficiency is improved compared to the system based on small molecule acceptors (such as Y6, etc.).

[0024] 2. Broadened application scenarios: In the present invention, the nanoparticles are further loaded in a low-cost hydrogel, and bulk hydrogel, hydrogel film, hydrogel microspheres, etc. can be obtained through subsequent treatment, which is convenient for recycling and reuse, and avoids secondary pollution to the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The specification drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. Among them:

[0026] Figure 1 It is a schematic diagram of a photocatalytic hydrogen evolution hydrogel loaded with organic photocatalyst nanoparticles involved in the present invention;

[0027] Figure 2 It is the molecular structural formula of high-efficiency oligomer acceptor materials TDY-α and TDY-β;

[0028] Figure 3 It is the molecular structural formula of donor materials PM6, D18, and PTQ10;

[0029] Figure 4 It is the 1 1H NMR of TDY-α and TDY-β;

[0030] Figure 5 It is the step schematic diagram of Example 1;

[0031] Figure 6 It is the SEM image of the nanoparticles based on PM6: TDY-α prepared in Example 1;

[0032] Figure 7 It is the SEM image of the hydrogel after drying prepared in Example 1;

[0033] Figure 8 It is a schematic diagram for comparing the hydrogen evolution ability of the hydrogel based on the PM6: TDY-α system with that of the hydrogel based on the PM6: Y6 system in Example 1. Detailed implementation manners

[0034] To make the above objects, features and advantages of the present invention more obvious and understandable, the following will describe the detailed implementation manners of the present invention in conjunction with the embodiments of the specification.

[0035] In the following description, many specific details are set forth to facilitate a thorough understanding of the present invention. However, the present invention may be implemented in other ways different from those described herein. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention fall within the scope of protection of the present invention.

[0036] Secondly, the so-called "one embodiment" or "embodiment" herein refers to a specific feature, structure or characteristic that may be included in at least one implementation manner of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that excludes other embodiments. It should be noted that, without conflict, the embodiments and features in the embodiments of the present invention may be combined with each other.

[0037] The materials and reagents selected in this embodiment and the control example are all commercially available products. Among them, Figure 1 A schematic diagram of the photocatalytic hydrogen-evolving hydrogel loaded with organic photocatalyst nanoparticles involved in the present invention is given. Figure 2 The molecular structural formulas of the highly efficient oligomer acceptor materials TDY-α and TDY-β are given. Figure 3 The molecular structural formulas of the donor materials PM6, D18, and PTQ10 are given. Figure 4 The 1 1H NMR of TDY-α and TDY-β is given. Example 1

[0038] A preparation method of a photocatalytic hydrogen-evolving hydrogel provided in this embodiment is as Figure 5 shown, and includes the following steps:

[0039] Step S1: Dissolve TDY-α (6.5 mg) and PM6 (2.8 mg) in 20 mL of chloroform, and magnetically stir at 60 °C for about 6 h to obtain a donor-acceptor blend solution.

[0040] Step S2: Slowly drop the above donor-acceptor blend solution into a TEBS aqueous solution (40 mL, 0.4 mg / mL), and maintain continuous ultrasonic treatment and ice bath during the dropping process. An internal ultrasonic vibration rod is used for ultrasonic treatment to obtain a microemulsion.

[0041] Step S3: Appropriately reduce the pressure of the above microemulsion to dry it, remove the residual chloroform in the system, and obtain a nanoparticle suspension. Subsequently, take samples, prepare specimens, and use SEM to observe the morphology and particle size of the nanoparticles, as Figure 6 shown.

[0042] Step S4: Add 300 mg of sodium alginate to the above nanoparticle suspension (about 36 mL), stir well, and magnetically stir at room temperature for about 1 h.

[0043] Step S5: Add a dilute calcium chloride solution, magnetically stir at room temperature for about 2 h to obtain a hydrogel solution loaded with organic photocatalyst nanoparticles. Subsequently, take samples, prepare specimens, and use SEM to observe the state of the dried hydrogel, as Figure 7 shown.

[0044] Photocatalytic activity test: Through a photocatalytic reactor, irradiate with a simulated solar lamp (300 W xenon lamp, AM1.5G filter), use a microsyringe to take the gas in the container every 2 h, and use gas chromatography separation technology to detect the gas composition of the sample and measure the hydrogen evolution concentration.

[0045] Step S6: Further concentrate the above hydrogel solution to prepare a bulk hydrogel.

[0046] Comparative Example 1

[0047] The difference between this Comparative Example 1 and Example 1 is that in Step S1, the acceptor material used is Y6. Other steps and methods are the same as those in Example 1.

[0048] Figure 8 The figure below shows the comparison chart of the hydrogen generation efficiency of the hydrogels prepared in Example 1 and Comparative Example 1 of the present invention. It can be seen from the figure that compared with the PM6:Y6 system, the hydrogen evolution ability of the system based on the highly efficient oligomeric acceptor (TDY-α) used in the present invention has been improved. Example 2

[0049] A preparation method of a photocatalytic hydrogen evolution hydrogel provided in this example includes the following steps:

[0050] Step S1: Dissolve TDY-α (6 mg) and D18 (2 mg) in 30 mL of chloroform, and magnetically stir at 60 °C for about 8 h to obtain a donor-acceptor blend solution.

[0051] Step S2: Slowly drop the above donor-acceptor blend solution into a TEBS aqueous solution (60 mL, 1.0 mg / mL), and maintain continuous ultrasonic and ice bath during the dropping process. The ultrasonic vibration is carried out by an in-built ultrasonic vibrator to obtain a microemulsion.

[0052] Step S3: Appropriately reduce the pressure of the above microemulsion to dry it, removing the residual chloroform in the system to obtain a nanoparticle suspension.

[0053] Step S4: Add 300 mg of sodium alginate to the above nanoparticle suspension (about 56 mL), stir well, and magnetically stir at room temperature for about 1 h.

[0054] Step S5: Spray the above solution into a chitosan solution (about 5 mg / mL) by the spraying method, and keep the chitosan solution magnetically stirred (500 rpm) during this process. After completion, magnetically stir at room temperature for about 2 h to obtain a suspension of hydrogel microspheres loaded with organic photocatalyst nanoparticles.

[0055] Step S6: Further concentrate the above hydrogel solution and freeze-dry it to obtain hydrogel microspheres. Example 3

[0056] A preparation method of a photocatalytic hydrogen evolution hydrogel provided in this example includes the following steps:

[0057] Step S1: Dissolve TDY-α (7.5 mg) and PTQ10 (2.5 mg) in 25 mL of chloroform, and magnetically stir at 60 °C for about 8 h to obtain a donor-acceptor blend solution.

[0058] Step S2: Slowly drop the above donor-acceptor blend solution into a TEBS aqueous solution (45 mL, 3.5 mg / mL), and keep continuous ultrasonic and ice bath during the dropping process. Use an in-built ultrasonic vibrating rod for ultrasonic treatment to obtain a microemulsion.

[0059] Step S3: Appropriately reduce the pressure of the above microemulsion to dry it, removing the residual chloroform in the system to obtain a nanoparticle suspension.

[0060] Step S4: Add 500 mg of sodium alginate to the above nanoparticle suspension (about 65 mL), stir well, and magnetically stir at room temperature for about 1 h.

[0061] Step S5: Slowly add the above solution to a gelatin solution (about 6 mg / mL), and keep the gelatin solution magnetically stirred (500 rpm) during this process. After completion, magnetically stir at room temperature for about 2 h to obtain a hydrogel solution loaded with organic photocatalyst nanoparticles.

[0062] Step S6: Further concentrate the above hydrogel solution, pour it into a flat mold, and freeze-dry it to obtain a hydrogel film. Example 4

[0063] A preparation method of a photocatalytic hydrogen evolution hydrogel provided in this example includes the following steps:

[0064] Step S1: Dissolve TDY-β (7.5 mg) and PTQ10 (2 mg) in 20 mL of chloroform, and magnetically stir at 65 °C for about 8 h to obtain a donor-acceptor blend solution.

[0065] Step S2: Slowly drop the above donor-acceptor blend solution into an aqueous TEBS solution (35 mL, 5.0 mg / mL), and maintain continuous ultrasonic treatment and ice bath during the dropping process. Use an in-built ultrasonic vibrator to obtain a microemulsion.

[0066] Step S3: Appropriately dry the above microemulsion under reduced pressure to remove the residual chloroform in the system, and obtain a nanoparticle suspension.

[0067] Step S4: Add 250 mg of sodium alginate to the above nanoparticle suspension (about 45 mL), stir well, and magnetically stir at room temperature for about 1 h.

[0068] Step S5: Add a dilute calcium chloride solution, and magnetically stir at room temperature for about 2 h to obtain a hydrogel solution loaded with organic photocatalyst nanoparticles. Further, add this hydrogel solution to a gelatin solution and continue magnetic stirring for about 2 h to obtain a hydrogel solution loaded with organic photocatalyst nanoparticles.

[0069] Step S6: Pour the above hydrogel solution into a flat mold and freeze-dry to obtain a hydrogel film. Example 5

[0070] A preparation method of a photocatalytic hydrogen evolution hydrogel provided in this example includes the following steps:

[0071] Step S1: Dissolve TDY-β (5 mg) and PM6 (1.5 mg) in 15 mL of chloroform, and magnetically stir at 65 °C for about 8 h to obtain a donor-acceptor blend solution.

[0072] Step S2: Slowly drop the above donor-acceptor blend solution into an aqueous TEBS solution (20 mL, 6.5 mg / mL), and maintain continuous ultrasonic treatment and ice bath during the dropping process. Use an in-built ultrasonic vibrator to obtain a microemulsion.

[0073] Step S3: Appropriately dry the above microemulsion under reduced pressure to remove the residual chloroform in the system, and obtain a nanoparticle suspension.

[0074] Step S4: Add 600 mg of sodium alginate to the above nanoparticle suspension (about 30 mL), stir well, and magnetically stir at room temperature for about 1 h.

[0075] Step S5: Spray the above solution into a mixed solution of chitosan (about 2 mg / mL) and gelatin (about 4 mg / mL) by the spray method, and maintain magnetic stirring (700 rpm) during this process. After completion, magnetically stir at room temperature for about 2 h to obtain a suspension of hydrogel microspheres loaded with organic photocatalyst nanoparticles.

[0076] Step S6: Further concentrate the above hydrogel solution and freeze-dry it to obtain hydrogel microspheres. Example 6

[0077] A preparation method of a photocatalytic hydrogen evolution hydrogel provided in this example includes the following steps:

[0078] Step S1: Dissolve TDY-β (7.5 mg) and D18 (2.5 mg) in 35 mL of chloroform, and magnetically stir at 60°C for about 8 h to obtain a donor-acceptor blend solution.

[0079] Step S2: Slowly drop the above donor-acceptor blend solution into an aqueous TEBS solution (60 mL, 6.0 mg / mL), and maintain continuous ultrasonic vibration and ice bath during the dropping process. Use an internal ultrasonic vibrator to obtain a microemulsion.

[0080] Step S3: Appropriately reduce the pressure of the above microemulsion to dry it and remove the residual chloroform in the system to obtain a nanoparticle suspension.

[0081] Step S4: Add 650 mg of sodium alginate to the above nanoparticle suspension (about 56 mL), stir well, and magnetically stir at room temperature for about 1 h.

[0082] Step S5: Spray the above solution into a mixed solution of a dilute calcium chloride solution and chitosan (about 4 mg / mL) by the spray method, and maintain magnetic stirring (600 rpm) during this process. After completion, magnetically stir at room temperature for about 2 h to obtain a suspension of hydrogel microspheres loaded with organic photocatalyst nanoparticles.

[0083] Step S6: Further concentrate the above hydrogel solution to obtain a bulk hydrogel.

[0084] In summary, the photocatalytic hydrogen evolution hydrogel loaded with organic photocatalyst nanoparticles of the present invention has good hydrogen evolution efficiency, and can be further prepared into hydrogel films, microspheres, etc. according to actual needs, which can effectively reduce secondary pollution, facilitate recycling and reuse, and broaden the application scenarios of photocatalytic hydrogels.

[0085] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a photocatalytic hydrogen evolution hydrogel, characterized in that: The preparation method comprises the following steps: Step S1, dissolving the high-efficiency oligomer acceptor material TDY-α or TDY-β and the donor material in an organic solvent, heating to completely dissolve them, and forming a good donor-acceptor blend solution, wherein the donor material is one of PM6, D18, and PTQ10; Step S2, slowly dripping the donor-acceptor blend solution into the TEBS aqueous solution, maintaining continuous ultrasound during the dripping process, to obtain a good microemulsion; Step S3, drying the microemulsion under reduced pressure to remove residual organic solvent in the system to obtain a nanoparticle suspension; Step S4, adding a hydrogel precursor material to the nanoparticle suspension and stirring thoroughly; Step S5, adding a gelation-promoting material solution to obtain a hydrogel solution loaded with organic photocatalyst nanoparticles.

2. The preparation method according to claim 1, characterized in that The organic solvent is a low boiling point organic solvent.

3. The preparation method according to claim 2, characterized in that: The organic solvent is chloroform.

4. The preparation method according to claim 1, characterized in that: The concentration of the donor-acceptor blend solution is 0.1-20 mg / mL.

5. The preparation method according to claim 1, characterized in that: The concentration of the TEBS aqueous solution is 0.1-10 mg / mL.

6. The preparation method according to any one of claims 1 to 5, characterized in that: In step 2, the ultrasonic treatment is carried out by using a built-in ultrasonic vibrator or an external ultrasonic cleaner, and the ultrasonic intensity is 200-1000W.

7. The preparation method according to any one of claims 1 to 5, characterized in that: In step 4, the concentration of the prepared solution is 1-30 mg / mL.

8. The preparation method according to any one of claims 1 to 5, characterized in that: The hydrogel precursor material is sodium alginate.

9. The preparation method according to any one of claims 1 to 5, characterized in that: The gelling material is one or more of calcium chloride, chitosan and gelatin.

10. The preparation method according to any one of claims 1 to 5, characterized in that: The preparation method further comprises: Step S6, treating the hydrogel solution to obtain block hydrogel, hydrogel film or hydrogel microspheres.

Images