Organic nano photocatalyst as well as preparation method and application thereof

Abstract

The invention provides an organic nano photocatalyst as well as a preparation method and application thereof, and belongs to the technical field of nano materials and photocatalysis. According to the method disclosed by the invention, a nonionic surfactant is adopted as a soft template, and the self-assembly process of the nano organic photocatalyst is regulated and controlled, so that a stably dispersed nano colloidal solution is obtained. According to the invention, 8 organic photocatalysts and a nonionic surfactant Tween (T20) are subjected to confinement co-assembly through a nano precipitation technology, such that the nano organic photocatalyst is obtained. The photocatalytic efficiency is remarkably improved through microenvironment regulation and control, and the hydrogen production performance of T20 / CNP90 can reach 520.17 mmol.g <-1 >. H <-1 > to the maximum extent. A universal strategy is provided for constructing a high-efficiency aqueous-phase organic photocatalyst.

Description

Technical Field

[0001] This invention relates to the fields of nanomaterials and photocatalysis, and particularly to an organic nanophotocatalyst, its preparation method, and its application. Background Technology

[0002] Photocatalytic water splitting for hydrogen production is a clean energy technology of great significance in addressing the energy crisis. Currently, most research on organic photocatalysts focuses on polymer semiconductor materials. However, common organic semiconductors are composed of large π-conjugated frameworks, which easily form micron-sized particles. This leads to a severe mismatch between light penetration depth (hundreds of nanometers) and exciton diffusion length (less than 20 nanometers), making it difficult for excitons to migrate to the reaction interface and causing rapid recombination, thus limiting photocatalytic efficiency. Although nanoprecipitation or microemulsion methods provide a simple way to prepare stable nanocatalysts using surfactants, it is generally believed in the field that they hinder electron transfer and tend to be removed after preparation. The role of surfactants in the photocatalytic process has always lacked systematic research, and the structure-activity mechanism remains unclear.

[0003] Currently, most research on organic photocatalysts focuses on polymer semiconductor materials. However, common polymer photocatalysts are composed of large π-conjugated frameworks, which easily form micron-sized particles. This leads to a severe mismatch between light penetration depth (hundreds of nanometers) and exciton diffusion length (less than 20 nanometers), making it difficult for excitons to migrate to the reaction interface and recombine rapidly, thus limiting photocatalytic efficiency.

[0004] Therefore, how to obtain an organic nanocatalyst with high photocatalytic efficiency, its preparation method, and its application are technical problems that need to be solved. Summary of the Invention

[0005] The purpose of this invention is to provide an organic nano-photocatalyst, its preparation method, and its application, in order to solve the technical problem that existing surfactants hinder electron transfer in the photocatalytic process.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing organic nano-photocatalysts, comprising the following steps: 1) Dissolve organic photocatalyst A in acetone to obtain solution A; Alternatively, organic photocatalyst B can be dissolved in chloroform to obtain solution B; 2) Dissolve the surfactant in water to obtain solution C; 3) Add solution A dropwise to solution C under stirring, evaporate the solvent in a water bath, and obtain a colloidal solution, which is the organic nano-photocatalyst; Alternatively, solution B can be added dropwise to solution C under stirring conditions, and the resulting microemulsion, obtained by ultrasonic dispersion, is an organic nano-photocatalyst.

[0007] Furthermore, the organic photocatalyst A comprises one or more of 1,8-naphthalenedicarboximide, poly(9,9-dioctylfluorene-co-benzothiadiazole), 3,4,5,6-tetra(9-carbazolyl)-o-phthalonitrile, 2,6-bis(4-cyanophenyl)-4-phenylpyridin-3,5-dionitrile, 2,6-bis(4-cyanophenyl)-4-(4'-fluoro-[1,1'-biphenyl]-4-yl)pyridin-3,5-dionitrile, 2,6-bis(4-cyanophenyl)-4-(naphthal-2-yl)pyridin-3,5-dionitrile, and 2,6-bis(4-cyanophenyl)-4-(9-phenyl-9-carbazol-3-yl)pyridin-3,5-dionitrile.

[0008] Furthermore, the organic photocatalyst B is (6,6)-phenyl-C 71 Methyl butyrate, wherein the surfactant is Tween 20.

[0009] Furthermore, the concentrations of solutions A and B are independently 0.1~3 mg / mL.

[0010] Furthermore, the concentration of solution C is 0.01~10 mg / mL.

[0011] Furthermore, in step 3), the water bath temperature is 40~80℃, the water bath time is 0.5~1h, and the ultrasonic dispersion time is 20~40min.

[0012] Furthermore, the concentration of organic photocatalyst A in the colloidal solution is 0.05~0.1 mg / mL.

[0013] The present invention also provides an organic nanophotocatalyst prepared by the above preparation method.

[0014] This invention also provides the application of the above-mentioned organic nano-photocatalyst in photocatalytic hydrogen production.

[0015] The beneficial effects of this invention are: 1. This invention proposes a co-assembly strategy of surfactants and organic photocatalysts to achieve the regulation of the interfacial microenvironment of organic nano-photocatalysts. The colloidal solution of the organic nano-photocatalyst obtained by this invention exhibits excellent stability and can be directly used in photocatalytic reactions without complex post-processing.

[0016] 2. The amphiphilic interface microenvironment, which is "hydrophobic inside and hydrophilic outside", inhibits non-radiative recombination in the photoreaction process on the one hand, and improves the hydrophilicity of the photocatalyst on the other hand, thus significantly improving the efficiency of photocatalytic hydrogen production.

[0017] 3. The organic nano-photocatalyst T20 / CNP90, which exhibits the highest hydrogen production performance, achieves a 16-fold performance improvement in hydrogen production compared to CNP90 alone, with a hydrogen production rate reaching 520.17 mmol·g. -1 ·h -1 (780.55 μmol·h -1 This is among the highest levels reported so far, significantly reducing the material consumption and energy cost per unit of hydrogen production. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the preparation method described in this invention.

[0019] Figure 2 These are scanning electron microscope images of T20 / CNP90 and CNP90 alone in this invention.

[0020] Figure 3 This is a comparison chart of the surface potential difference between T20 / CNP90 and CNP90 alone in this invention, and after being placed for one month.

[0021] Figure 4 These are the Fourier transform infrared spectra of T20 / CNP90 and CNP90 alone in this invention.

[0022] Figure 5 These are the UV-Vis absorption spectra of T20 / CNP90 and CNP90 alone in this invention.

[0023] Figure 6 These are the fluorescence intensity spectra of T20 / CNP90 and CNP90 alone in this invention.

[0024] Figure 7 These are the fluorescence lifetime spectra of T20 / CNP90 and CNP90 alone in this invention.

[0025] Figure 8 These are the fluorescence quantum yield spectra of T20 / CNP90 and CNP90 alone in this invention.

[0026] Figure 9 These are the electron paramagnetic resonance spectra of T20 / CNP90 and CNP90 alone in this invention.

[0027] Figure 10 This is a time spectrum of photocatalytic water splitting to hydrogen production using T20 / CNP90 and CNP90 alone in this invention.

[0028] Figure 11 These are the stability test spectra of T20 / CNP90 and CNP90 alone in this invention.

[0029] Figure 12This is a comparison chart of the hydrogen production performance of the organic nanophotocatalyst of the present invention compared to the original photocatalyst. Detailed Implementation

[0030] This invention provides a method for preparing organic nano-photocatalysts, comprising the following steps: 1) Dissolve organic photocatalyst A in acetone to obtain solution A; Alternatively, organic photocatalyst B can be dissolved in chloroform to obtain solution B; 2) Dissolve the surfactant in water to obtain solution C; 3) Add solution A dropwise to solution C under stirring, evaporate the solvent in a water bath, and obtain a colloidal solution, which is the organic nano-photocatalyst; Alternatively, solution B can be added dropwise to solution C under stirring conditions, and the resulting microemulsion, obtained by ultrasonic dispersion, is an organic nano-photocatalyst.

[0031] In this invention, the organic photocatalyst A comprises 1,8-naphthalenedimide, poly(9,9-dioctylfluorene-co-benzothiadiazole), 3,4,5,6-tetrakis(9-carbazolyl)-o-phthalonitrile, 2,6-bis(4-cyanophenyl)-4-phenylpyridine-3,5-dionitrile, and 2,6-bis(4-cyanophenyl)-4-(4'-fluoro-[1,1'-biphenyl]-4-yl One or more of pyridine-3,5-dionitrile, 2,6-bis(4-cyanophenyl)-4-(naphth-2-yl)pyridine-3,5-dionitrile and 2,6-bis(4-cyanophenyl)-4-(9-phenyl-9-carbazole-3-yl)pyridine-3,5-dionitrile, preferably 2,6-bis(4-cyanophenyl)-4-(9-phenyl-9-carbazole-3-yl)pyridine-3,5-dionitrile.

[0032] In this invention, the organic photocatalyst B is preferably (6,6)-phenyl C. 71 Methyl butyrate, wherein the surfactant is preferably Tween 20, the molecular weight of which is 1227.54 mg / mol.

[0033] In this invention, the concentrations of solution A and solution B are independently 0.1~3 mg / mL, preferably 0.5~2.5 mg / mL, and more preferably 1~2 mg / mL.

[0034] In this invention, the concentration of solution C is 0.01~10 mg / mL, preferably 0.1~9 mg / mL, and more preferably 1~8 mg / mL.

[0035] In this invention, in step 3), the temperature of the water bath is 40~80℃, preferably 50~80℃, and more preferably 60~80℃; the water bath time is 0.5~1h, preferably 1h; and the ultrasonic dispersion time is 20~40min, preferably 25~35min, and more preferably 30min.

[0036] In this invention, the concentration of organic photocatalyst A in the colloidal solution is 0.05~0.1 mg / mL, preferably 0.05~0.08 mg / mL, and more preferably 0.06 mg / mL.

[0037] In this invention, the above preparation method utilizes the co-assembly of the surfactant Tween 20 and the photocatalyst to regulate the microenvironment of the photocatalyst interface, forming an amphiphilic structure that is hydrophobic internally and hydrophilic externally. This suppresses non-radiative recombination during the photoreaction process and also acts as a stabilizer, inhibiting the aggregation of nanocatalysts and yielding a colloidal solution of nanofiber photocatalyst. This improves the photocatalytic hydrogen production performance.

[0038] The present invention also provides an organic nanophotocatalyst prepared by the above preparation method.

[0039] This invention also provides the application of the above-mentioned organic nano-photocatalyst in photocatalytic hydrogen production.

[0040] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0041] Example 1

[0042] T20 / CNP90 Synthesis

[0043] The organic photocatalyst 2,6-bis(4-cyanophenyl)-4-(9-phenyl-9-carbazol-3-yl)pyridine-3,5-dionitrile (CNP90) was dissolved in acetone to a concentration of 0.5 mg / mL. 3 mL of the acetone solution was gradually added dropwise to an aqueous solution (25 mL, 2 mg / mL) containing Tween 20 (T20) at a rotation speed of 1000 rpm. After stirring for 1 minute, the mixture was placed in a 50°C water bath for 0.5 h to evaporate the acetone, thus preparing an orange-yellow colloidal solution in which the organic nano-photocatalyst was stably present.

[0044] Example 2

[0045] T20 / NPI Synthesis

[0046] The photocatalyst 1,8-naphthalenedimide (NPI) was dissolved in acetone to a concentration of 0.5 mg / mL. 3 mL of the acetone solution was gradually added dropwise to an aqueous solution (25 mL, 2 mg / mL) containing Tween 20 (T20) at a rotation speed of 1000 rpm. After stirring for 1 minute, the mixture was placed in a water bath at 40-80℃ for 1 hour to evaporate the acetone, thus preparing a colloidal solution in which the organic nano-photocatalyst was stably present.

[0047] Example 3

[0048] T20 / F8BT

[0049] The photocatalyst poly(9,9-dioctylfluorene-co-benzothiadiazole) (F8BT) was dissolved in acetone to a concentration of 0.5 mg / mL. 3 mL of the acetone solution was gradually added dropwise to an aqueous solution (25 mL, 2 mg / mL) containing Tween 20 (T20) at a rotation speed of 1000 rpm. After stirring for 1 minute, the mixture was placed in a water bath at 40-80℃ for 0.5 h to evaporate the acetone, thus preparing a colloidal solution in which the organic nano-photocatalyst was stably present.

[0050] Example 4

[0051] T20 / 4CzPN

[0052] The photocatalyst 3,4,5,6-tetrakis(9-carbazolyl)-phthalonitrile (4CzPN) was dissolved in acetone to a concentration of 0.5 mg / mL. 3 mL of the acetone solution was gradually added dropwise to an aqueous solution (25 mL, 2 mg / mL) containing Tween 20 (T20) at a rotation speed of 1000 rpm. After stirring for 1 minute, the mixed solution was placed in a water bath at 40-80℃ for 1 hour to evaporate the acetone, thus preparing a colloidal solution in which the organic nano-photocatalyst was stably present.

[0053] Example 5

[0054] T20 / CNP8

[0055] The photocatalyst 2,6-bis(4-cyanophenyl)-4-phenylpyridine-3,5-dionitrile (CNP8) was dissolved in acetone to a concentration of 0.5 mg / mL. 3 mL of the acetone solution was gradually added dropwise to an aqueous solution (25 mL, 2 mg / mL) containing Tween 20 (T20) at a rotation speed of 1000 rpm. After stirring for 1 minute, the mixture was placed in a water bath at 40-80℃ for 0.5 h to evaporate the acetone, thus preparing a colloidal solution in which the organic nano-photocatalyst was stably present.

[0056] Example 6

[0057] T20 / CNP147

[0058] The photocatalyst 2,6-bis(4-cyanophenyl)-4-(4'-fluoro-[1,1'-biphenyl]-4-yl)pyridine-3,5-dionitrile (CNP147) was dissolved in acetone to a concentration of 0.5 mg / mL. 3 mL of the acetone solution was gradually added dropwise to an aqueous solution (25 mL, 2 mg / mL) containing Tween 20 (T20) at a rotation speed of 1000 rpm. After stirring for 1 minute, the mixture was placed in a water bath at 40-80℃ to evaporate the acetone, thus preparing a colloidal solution in which the organic nano-photocatalyst was stably present.

[0059] Example 7

[0060] T20 / CNP36

[0061] The photocatalyst 2,6-bis(4-cyanophenyl)-4-(naphth-2-yl)pyridine-3,5-dionitrile (CNP36) was dissolved in acetone to a concentration of 0.5 mg / mL. 3 mL of the acetone solution was gradually added dropwise to an aqueous solution (25 mL, 2 mg / mL) containing Tween 20 (T20) at a rotation speed of 1000 rpm. After stirring for 1 minute, the mixture was placed in a water bath at 40-80℃ for 1 hour to evaporate the acetone, thus preparing a colloidal solution in which the organic nano-photocatalyst was stably present.

[0062] Example 8

[0063] T20 / PC 71 BM

[0064] Photocatalyst (6,6)-phenylC 71 methyl butyrate (PC) 71 BM) is dissolved in chloroform at a concentration of 0.5 mg / mL. 3 mL of acetone solution is gradually added dropwise to an aqueous solution (25 mL, 2 mg / mL) containing Tween 20 (T20) for 0.5 h. After sonication with a probe for 30 minutes, the mixed solution is placed in a water bath at 40-80 °C to evaporate the acetone, thus preparing a microemulsion.

[0065] Comparative Example 1

[0066] CNP90 Synthesis

[0067] The molecular photocatalyst 2,6-bis(4-cyanophenyl)-4-(9-phenyl-9-carbazol-3-yl)pyridine-3,5-dionitrile (CNP90) was dissolved in acetone to a concentration of 0.5 mg / mL. 3 mL of the acetone solution was gradually added dropwise to 25 mL of water at a rotation speed of 1000 rpm. After stirring for 1 minute, the mixture was placed in a water bath at 40-80℃ for 0.5 h to evaporate the acetone, resulting in an orange-yellow colloidal solution. The nano-photocatalyst showed obvious aggregation.

[0068] Comparative Example 2

[0069] NPI synthesis

[0070] The photocatalyst 1,8-naphthalenedimide (NPI) was dissolved in acetone to a concentration of 0.5 mg / mL. 3 mL of the acetone solution was gradually added dropwise to 25 mL of water at a rotation speed of 1000 r / min. After stirring for 1 minute, the mixture was placed in a water bath at 40-80℃ for 1 hour to evaporate the acetone, thus preparing a colloidal solution. The nano-photocatalyst showed obvious aggregation.

[0071] Comparative Example 3

[0072] F8BT Synthesis

[0073] The photocatalyst poly(9,9-dioctylfluorene-co-benzothiadiazole) (F8BT) was dissolved in acetone to a concentration of 0.5 mg / mL. 3 mL of the acetone solution was gradually added dropwise to 25 mL of water at a rotation speed of 1000 r / min. After stirring for 1 minute, the mixed solution was placed in a water bath at 40-80℃ for 0.5 h to evaporate the acetone, thus preparing a colloidal solution. The nano-photocatalyst showed obvious aggregation.

[0074] Comparative Example 4

[0075] 4CzPN synthesis

[0076] The photocatalyst 3,4,5,6-tetrakis(9-carbazolyl)-phthalonitrile (4CzPN) was dissolved in acetone to a concentration of 0.5 mg / mL. 3 mL of the acetone solution was gradually added dropwise to 25 mL of water at a rotation speed of 1000 rpm. After stirring for 1 minute, the mixture was placed in a water bath at 40-80℃ for 1 hour to evaporate the acetone, thus preparing a colloidal solution. The nano-photocatalyst showed significant aggregation.

[0077] Comparative Example 5

[0078] CNP8 Synthesis

[0079] The photocatalyst 2,6-bis(4-cyanophenyl)-4-phenylpyridine-3,5-dionitrile (CNP8) was dissolved in acetone to a concentration of 0.5 mg / mL. 3 mL of the acetone solution was gradually added dropwise to 25 mL of water at a rotation speed of 1000 rpm. After stirring for 1 minute, the mixture was placed in a water bath at 40-80℃ for 0.5 h to evaporate the acetone, thus preparing a colloidal solution. The nano-photocatalyst showed obvious aggregation.

[0080] Comparative Example 6

[0081] CNP147 Synthesis

[0082] The photocatalyst 2,6-bis(4-cyanophenyl)-4-(4'-fluoro-[1,1'-biphenyl]-4-yl)pyridine-3,5-dionitrile (CNP147) was dissolved in acetone to a concentration of 0.5 mg / mL. 3 mL of the acetone solution was gradually added dropwise to 25 mL of water at a rotation speed of 1000 rpm. After stirring for 1 minute, the mixture was placed in a water bath at 40-80℃ for 1 hour to evaporate the acetone, thus preparing a colloidal solution. The nano-photocatalyst showed significant aggregation.

[0083] Comparative Example 7

[0084] CNP36 Synthesis

[0085] The photocatalyst 2,6-bis(4-cyanophenyl)-4-(naphth-2-yl)pyridine-3,5-dionitrile (CNP36) was dissolved in acetone to a concentration of 0.5 mg / mL. 3 mL of the acetone solution was gradually added dropwise to 25 mL of water at a rotation speed of 1000 rpm. After stirring for 1 minute, the mixture was placed in a water bath at 40-80℃ for 0.5 h to evaporate the acetone, thus preparing a colloidal solution. The nano-photocatalyst showed significant aggregation.

[0086] Comparative Example 8

[0087] PC 71 BM Synthesis

[0088] Photocatalyst (6,6)-phenylC 71 methyl butyrate (PC) 71 BM) is dissolved in chloroform at a concentration of 0.5 mg / mL. 3 mL of acetone solution is gradually added dropwise to 25 mL of water. After sonication with a probe for 30 minutes, the mixture is placed in a water bath at 40-80℃ for 1 hour to evaporate the acetone, thus preparing a microemulsion.

[0089] Experiments and Data

[0090] The T20 / CNP90 prepared in Example 1 and the CNP90 in Comparative Example 1 were observed by electron microscopy, surface potential difference was measured, Fourier transform infrared spectroscopy was performed, ultraviolet-visible absorption was measured, fluorescence and fluorescence lifetime were measured, paramagnetic resonance spectroscopy was performed, and photocatalytic hydrogen production rate was measured. The results of the above detection and analysis are as follows: (1) Scanning electron microscopy observation Depend on Figure 2 It can be seen that, Figure 2 (Left) corresponds to the CNP90 microstructure, which is a fibrous structure with an average size greater than 3 μm; while Figure 2 (Right) The microstructure of T20 / CNP90 is a uniformly dispersed fibrous structure with an average size of less than 2 μm. This indicates that the optimization of the preparation method successfully controlled the size of the nanofiber catalyst.

[0091] (2) Surface potential difference test

[0092] Figure 3 As shown, the initial surface potential difference between CNP90 and T20 / CNP90 was -14mV and -20mV, respectively. After 30 days of storage, it changed to -0.1mV and -21mV, respectively, indicating that T20 / CNP90 has good colloidal storage stability.

[0093] (3) Fourier transform infrared test

[0094] Figure 4 As shown, C≡N was observed at 2229 cm⁻¹ in both T20 / CNP90 and CNP90 samples. -1 The stretching vibration at this location represents the characteristic functional group of CNP90. After co-assembly, T20 / CNP90 exhibits a 1721 cm⁻¹ vibration. -1 At C=O, 2820cm -1 and 2920cm -1 The stretching vibration peak of CH2 indicates the successful co-assembly of surfactant T20 and molecular catalyst CNP90.

[0095] (4) Ultraviolet-Visible Absorption Test

[0096] Depend on Figure 5 It can be seen that T20 / CNP90 and CNP90 have the same absorption peak trend, but T20 / CNP90 has a slightly higher absorption intensity than CNP90, indicating that Tween 20 (T20) can improve the dispersibility of CNP90.

[0097] (5) Fluorescence intensity test

[0098] Depend on Figure 6 It can be seen that the fluorescence intensity of T20 / CNP90 is more than twice that of CNP90, indicating that the co-assembly of Tween 20 (T20) can reduce non-radiative recombination loss.

[0099] (6) Fluorescence lifetime test

[0100] Depend on Figure 7 It can be seen that the fluorescence lifetime of T20 / CNP90 increased from 6 nanoseconds of CNP90 to 14 nanoseconds, indicating that the charge separation time increased after CNP90 was co-assembled with Tween 20 (T20).

[0101] (7) Fluorescence quantum yield test

[0102] Depend on Figure 8Fluorescence quantum yield indicates the efficiency with which a photocatalyst converts absorbed photons into emitted photons. The fluorescence quantum yield of T20 / CNP90 increased from 1.4% for CNP90 to 4.3%, indicating that the co-assembly of CNP90 with Tween 20 (T20) enhances the fluorescence radiative recombination intensity, improves luminescence efficiency, and increases the number of excitons available for photocatalysis, consistent with the enhanced hydrogen production performance of the photocatalyst.

[0103] (8) Electron paramagnetic resonance spectroscopy detection

[0104] like Figure 9 As shown, the presence of these charges can be indicated by the signal quenching of TEMPO (2,2,6,6-tetramethyl-1-piperidinoxy, nitroxide radical), because the free charges generated by the nanofiber photocatalyst under illumination are captured by TEMPO and reduced to tetramethylpiperidine (TEMP). Under the same irradiation conditions, T20 / CNP90 exhibited more significant TEMPO signal quenching than CNP90 compared to the blank control group. This indicates that the T20 / CNP90 system can generate more photogenerated free charges (i.e., electrons and holes) under visible light irradiation.

[0105] (9) Photocatalytic hydrogen production rate test

[0106] like Figure 10 As shown, the synthesized T20 / CNP90 colloidal solution was directly used for photocatalytic testing. To ensure accuracy, the photocatalytic activity was measured at least three times for each experimental condition. Under visible light irradiation from a 300W xenon lamp (λ>420nm), 1.5mg of CNP90 produced 243.8μmol of hydrogen gas within 5 hours, corresponding to a hydrogen evolution rate (HER) of 48.8μmol·L⁻¹. ¹. Notably, 1.5 mg of T20 / CNP90 colloidal solution can generate 3901.1 μmol of hydrogen gas in the same time period, with a HER of 780.22 μmol·L⁻¹. ¹.

[0107] Figure 11 As shown, a cyclic photocatalytic hydrogen evolution experiment was set up to evaluate the photocatalytic stability of T20 / CNP90 and CNP90 nanofiber photocatalysts. Each cycle consisted of 5 hours of irradiation, followed by ascorbic acid replenishment and degassing of the system. This process was repeated for five consecutive cycles. Throughout the test, the hydrogen evolution rate (HER) remained stable. In the last cycle, the HER remained at 85% of that in the first cycle, indicating good photocatalytic stability.

[0108] The method for evaluating the photocatalytic hydrogen evolution activity in water splitting provided by this invention is as follows: Changes in hydrogen release can be used as an indicator of photocatalytic activity. The cumulative amount of gas released was monitored every 60 minutes using a gas chromatograph (Shimadzu GC2014C) equipped with a thermal conductivity detector (TCD). Colloidal solutions of 25 mL LT20 / CNP90 and CNP90 were placed in a Pofil 6A vacuum online micro-gas acquisition system. The system contained ascorbic acid as a sacrificial electron donor and H2PtCl6·6H2O as a co-catalyst during the reaction. The light source was a 300W xenon lamp (PerfectLight PLS-SXE300) equipped with a cutoff filter (>420nm, 100mWcm). -2 The reaction temperature was maintained at 10℃.

[0109] As can be seen from the above embodiments, this invention provides an organic nano-photocatalyst, its preparation method, and its application. The method of this invention uses a nonionic surfactant as a soft template to regulate the self-assembly process of the nano-organic photocatalyst, obtaining a stable dispersed nano-colloidal solution. This invention uses nanoprecipitation technology to confinedly co-assemble eight kinds of organic photocatalysts with the nonionic surfactant Tween (T20), respectively, to obtain nano-organic photocatalysts. The hydrogen production performance of the organic nano-photocatalysts of this invention is improved by 3, 2, 4, 7, 2, 5, 15, and 16 times compared to the original photocatalysts, as shown in the results (e.g., ...). Figure 12 The photocatalytic efficiency was significantly improved through microenvironment regulation, resulting in a maximum hydrogen production performance of 520.17 mmol·g for T20 / CNP90. -1 ·h -1 This provides a general strategy for constructing highly efficient aqueous organic photocatalysts.

[0110] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an organic nano-photocatalyst, characterized in that, Includes the following steps: 1) Dissolve organic photocatalyst A in acetone to obtain solution A; Alternatively, organic photocatalyst B can be dissolved in chloroform to obtain solution B; 2) Dissolve the surfactant in water to obtain solution C; 3) Add solution A dropwise to solution C under stirring, evaporate the solvent in a water bath, and obtain a colloidal solution, which is the organic nano-photocatalyst; Alternatively, solution B can be added dropwise to solution C under stirring conditions, and the resulting microemulsion can be obtained by ultrasonic dispersion, which is the organic nano-photocatalyst.

2. The method for preparing the organic nanophotocatalyst according to claim 1, characterized in that, The organic photocatalyst A comprises one or more of 1,8-naphthalenedimide, poly(9,9-dioctylfluorene-co-benzothiadiazole), 3,4,5,6-tetra(9-carbazolyl)-o-phthalonitrile, 2,6-bis(4-cyanophenyl)-4-phenylpyridin-3,5-dionitrile, 2,6-bis(4-cyanophenyl)-4-(4'-fluoro-[1,1'-biphenyl]-4-yl)pyridin-3,5-dionitrile, 2,6-bis(4-cyanophenyl)-4-(naphth-2-yl)pyridin-3,5-dionitrile, and 2,6-bis(4-cyanophenyl)-4-(9-phenyl-9-carbazol-3-yl)pyridin-3,5-dionitrile.

3. The method for preparing the organic nanophotocatalyst according to claim 2, characterized in that, The organic photocatalyst B is (6,6)-phenyl C 71 Methyl butyrate, wherein the surfactant is Tween 20.

4. The method for preparing the organic nanophotocatalyst according to any one of claims 1 to 3, characterized in that, The concentrations of solutions A and B are independently 0.1~3 mg / mL.

5. The method for preparing the organic nanophotocatalyst according to claim 4, characterized in that, The concentration of solution C is 0.01~10 mg / mL.

6. The method for preparing the organic nanophotocatalyst according to claim 1 or 5, characterized in that, In step 3), the water bath temperature is 40~80℃, the water bath time is 0.5~1h, and the ultrasonic dispersion time is 20~40min.

7. The method for preparing the organic nanophotocatalyst according to claim 6, characterized in that, The concentration of organic photocatalyst A in the colloidal solution is 0.05~0.1 mg / mL.

8. The organic nanophotocatalyst prepared by the preparation method according to any one of claims 1 to 7.

9. The application of the organic nanophotocatalyst according to claim 8 in photocatalytic hydrogen production.

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