Deuterated organic semiconductor photocatalyst, preparation method thereof and photocatalytic hydrogen production method

Abstract

The invention relates to a deuterated organic semiconductor photocatalyst which is a deuterated polymer 2, 4, 5, 6-tetra (9-carbazolyl)-isophthalonitrile. The method has the beneficial effects that the phonon effect and the carrier dynamics process in the photocatalysis process are modulated by using isotope substitution, and a distinctive method is provided for realizing efficient semiconductor photocatalysis. The deuterated carbazole-cyanobenzene conjugated polymer is synthesized by substituting carbazole with deuterated carbazole, and due to the fact that deuterium substitutes hydrogen, stretching and bending energy of a C-D bond is weakened, phonon energy of a catalyst is reduced, the non-radiative attenuation process of carriers is effectively inhibited, the service life of the carriers of a deuterated sample is longer, and the separation efficiency of photo-induced electrons and holes is obviously improved; therefore, the generation rate of hydrogen produced by visible light catalytic decomposition of water is higher, and the effect of improving the activity of the catalyst is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of photocatalyst preparation, and in particular to a deuterated organic semiconductor photocatalyst and a preparation method thereof, and a photocatalytic hydrogen production method. Background Art

[0002] Hydrogen energy is a clean energy that can replace fossil fuels, but the current hydrogen production process still relies on fossil fuels. Hydrogen energy is receiving more and more attention in the world today as a clean energy. Compared with traditional fossil fuels such as oil and natural gas, the only byproduct of hydrogen combustion is water, and it does not produce greenhouse gases such as carbon dioxide. Therefore, it is considered to be an environmentally friendly and sustainable form of energy. In order to achieve sustainable green hydrogen production technology, photocatalytic water splitting hydrogen production technology is considered to be one of the most ideal green hydrogen production technologies. Compared with traditional hydrogen production methods, photocatalytic hydrogen production technology has the advantages of low carbon emissions, no pollution and a wide range of raw material sources. Organic polymer semiconductors can optimize specific properties through molecular design and structural regulation, thereby achieving adjustable band structure, high light absorption coefficient, flexible processability and low manufacturing cost, and are widely used as effective catalysts for photocatalytic water splitting. However, despite the many advantages of organic polymer semiconductor photocatalysts, due to their low dielectric constant, poor photogenerated carrier separation ability, strong exciton effect and other disadvantages, their performance in catalyzing free-carrier water splitting to produce hydrogen is still low.

[0003] The low dielectric constant of polymer organic semiconductors makes it easy for electrons to couple with the local lattice, which sets a basic internal limit for the migration and diffusion of carriers in polymer semiconductors. For most polymer organic semiconductors rich in hydrogen (H), compared with other elements, the deuterium (D) isotope substitution strategy, although only one more neutron, doubles the atomic mass, and the vibration frequency of the chemical bond will change significantly, which is expected to induce changes in the phonon effect. For example, Wang et al. [9] fully deuterated the Ir(ppy)3 molecule. Due to the significant difference in atomic mass between D and H, the stretching and bending energy of the Ir(ppy)3 molecule was reduced. When the CH bond in the semiconductor photocatalyst is replaced by the CD bond, the CD bond will vibrate at a lower frequency than the CH bond (the vibration frequency ratio is about 0.7), which is expected to cause changes in the phonon system with vibration as the basic unit inside the polymer organic semiconductor photocatalyst, thereby having great potential to induce changes in the interaction between electrons and phonons. Therefore, it is of great significance to consider the electron-phonon interaction within polymer organic semiconductors, design the semiconductor photocatalyst structure based on the deuteration strategy, and regulate the electron-phonon interaction to improve the photocatalytic reaction performance of polymer organic semiconductor photocatalysts. Summary of the invention

[0004] The technical problem to be solved by the present invention is to study a deuterated organic semiconductor photocatalyst and a preparation method thereof and a photocatalytic hydrogen production method, so as to improve the migration and transport efficiency of photogenerated carriers and enhance the photocatalytic hydrogen production performance.

[0005] The technical solution of the present invention to solve the above technical problems is as follows:

[0006] A deuterated organic semiconductor photocatalyst is a deuterated polymer 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile. The structural formula of the deuterated polymer 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile is as follows:

[0007]

[0008] The beneficial effect of the present invention is that the present invention uses isotope substitution to regulate phonons in the photocatalytic process, and provides a unique catalyst design and regulation method for achieving efficient semiconductor photocatalysis. Deuterated carbazole-cyanobenzene conjugated polymers are synthesized by replacing carbazole with deuterated carbazole. From fluorescence measurement, it can be observed that the carrier lifetime of the deuterated sample is longer, and the separation efficiency of photogenerated electrons and holes is significantly improved. The variable temperature fluorescence spectrum data shows that the optical phonon energy is weakened and the Huang-Rhys factor S is enhanced. The internal conversion between the high vibration energy level of the ground state and the low vibration energy level of the excited state in the catalyst is the main driving force for the non-radiative decay of carriers. According to Fermi's golden rule, the internal conversion rate is negatively correlated with the Huang-Rhys factor S. Therefore, the deuteration process inhibits the internal conversion process, that is, the non-radiative deactivation of electrons is reduced, and the carrier lifetime is extended, thereby resulting in a higher visible light catalytic decomposition of water to produce hydrogen production rate, thereby achieving the effect of improving the activity of the catalyst.

[0009] Based on the above technical solution, the present invention can also be improved as follows.

[0010] Another technical solution of the present invention is as follows:

[0011] A method for preparing a deuterated organic semiconductor photocatalyst comprises the following steps:

[0012] Preparation of deuterated 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile:

[0013] Step 01, slowly add tetrahydrofuran solution to deuterated carbazole and sodium hydride, and stir;

[0014] Step 02, adding tetrafluoroisophthalonitrile tetrahydrofuran solution and stirring;

[0015] Step 03, adding deionized water to the reaction mixture;

[0016] Step 04: under reduced pressure, the obtained mixture was concentrated, and washed with deionized water and ethanol to obtain a crude product;

[0017] Step 05, the crude product is purified by recrystallization to obtain deuterated 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile;

[0018] Preparation of deuterated polymer 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile;

[0019] Step 06, dissolving deuterated 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile in anhydrous chloroform to obtain a monomer solution;

[0020] Step 07, adding the monomer solution dropwise into a mixed solution of anhydrous ferric chloride and anhydrous chloroform;

[0021] Step 08, stirring, after the stirring is completed, adding methanol, stirring, and washing the obtained product with hydrochloric acid;

[0022] Step 09, filter and wash with deionized water;

[0023] Step 10, purification;

[0024] Step 11: drying to obtain a deuterated polymer 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile.

[0025] Furthermore, step 01 is performed at room temperature in an argon atmosphere.

[0026] Further, in step 05, the crude product is passivated by recrystallization from cyclohexane or dichloromethane.

[0027] Furthermore, in step 10, Soxhlet extraction is used for purification: tetrahydrofuran and methanol are sequentially added to the product for purification.

[0028] Another technical solution of the present invention is as follows:

[0029] A photocatalytic hydrogen production method uses the deuterated polymer 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile prepared as above as a photocatalyst to produce hydrogen through photocatalysis.

[0030] Furthermore, the photocatalytic hydrogen production includes the following steps: placing the deuterated polymer 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile in a beaker, adding pure water and triethanolamine; placing the beaker in an ultrasonicator for ultrasonication to effectively disperse the deuterated polymer 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile in the liquid; pouring the liquid into a reactor filled with water to be decomposed to produce hydrogen through photocatalysis.

[0031] Furthermore, the reaction temperature in the reactor was 10° C., and a xenon lamp light source was used to irradiate the solution in the reactor. The xenon lamp light source power was 15 W and the wavelength of the light wave was greater than 420 nm. The solution in the reactor was stirred at a stirring rate of 250 rpm. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The structures of monomer 4CzIPN, polymer poly-4CzIPN, monomer deuterated 4CzIPN, and polymer deuterated D-poly-4CzIPN (from left to right);

[0033] Figure 2 XRD patterns of poly-4CzIPN and D-poly-4CzIPN;

[0034] Figure 3 FTIR graphs of poly-4CzIPN and D-poly-4CzIPN;

[0035] Figure 4 UV-vis-DRS images of poly-4CzIPN and D-poly-4CzIPN;

[0036] Figure 5 Tacu plots of poly-4CzIPN and D-poly-4CzIPN;

[0037] Figure 6 Photoluminescence (PL) images of poly-4CzIPN and D-poly-4CzIPN;

[0038] Figure 7 is a transient fluorescence lifetime curve of the photocatalytic material;

[0039] Figure 8 Temperature-dependent photoluminescence spectra of poly-4CzIPN and D-poly-4CzIPN samples in the temperature range of 4.4K to 300K;

[0040] Fig. 9 The graph shows the hydrogen production of poly-4CzIPN and D-poly-4CzIPN. DETAILED DESCRIPTION

[0041] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0042] like Figures 1 to 9As shown, in Example 1 of the present invention, a deuterated organic semiconductor photocatalyst is a deuterated polymer 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile, and the structural formula of the deuterated polymer 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile is as follows:

[0043]

[0044] The present invention uses isotope substitution to modulate phonons in the photocatalytic process, and provides a unique catalyst design method for achieving efficient semiconductor photocatalysis. Deuterated carbazole-cyanobenzene conjugated polymers are synthesized by replacing carbazole with deuterated carbazole. From fluorescence measurement, it can be observed that the carrier lifetime of the deuterated sample is longer, and the separation efficiency of photogenerated electrons and holes is significantly improved. The variable temperature fluorescence spectrum data shows that the optical phonon energy is weakened and the Huang-Rhys factor S is enhanced. The internal conversion between the high vibration energy level of the ground state and the low vibration energy level of the excited state in the catalyst is the main driving force for the non-radiative decay of carriers. According to Fermi's golden rule, the internal conversion rate is negatively correlated with the Huang-Rhys factor S. Therefore, the deuteration process inhibits the internal conversion process, that is, the non-radiative deactivation of electrons is reduced, and the carrier lifetime is extended, thereby resulting in a higher visible light catalytic decomposition of water to produce hydrogen production rate, thereby achieving the effect of improving the activity of the catalyst.

[0045] Embodiment 2 of the present invention provides a method for preparing a deuterated organic semiconductor photocatalyst, comprising the following steps:

[0046] Preparation of deuterated 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile:

[0047] Step 01, slowly add tetrahydrofuran solution to deuterated carbazole and sodium hydride, and stir;

[0048] Step 02, adding tetrafluoroisophthalonitrile tetrahydrofuran solution and stirring;

[0049] Step 03, adding deionized water to the reaction mixture;

[0050] Step 04, under reduced pressure, concentrating the obtained mixture, and washing with deionized water and ethanol to obtain a crude product;

[0051] Step 05, the crude product is purified by recrystallization to obtain deuterated 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile;

[0052] Preparation of deuterated polymer 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile;

[0053] Step 06, dissolving deuterated 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile in anhydrous chloroform to obtain a monomer solution;

[0054] Step 07, adding the monomer solution dropwise into a mixed solution of anhydrous ferric chloride and anhydrous chloroform;

[0055] Step 08, stirring, after the stirring is completed, adding methanol, stirring, and washing the obtained product with hydrochloric acid;

[0056] Step 09, filter and wash with deionized water;

[0057] Step 10, purification;

[0058] Step 11: drying to obtain a deuterated polymer 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile.

[0059] Embodiment 3 of the present invention is a method for preparing a deuterated organic semiconductor photocatalyst. Based on Embodiment 2, step 01 is performed at room temperature in an argon atmosphere.

[0060] Embodiment 4 of the present invention is a method for preparing a deuterated organic semiconductor photocatalyst. Based on Embodiment 3, in step 05, the crude product is passivated by recrystallization from cyclohexane or dichloromethane.

[0061] Example 5 of the present invention is a method for preparing a deuterated organic semiconductor photocatalyst. Based on Example 4, Soxhlet extraction is used for purification in step 10: tetrahydrofuran and methanol are added to the product in sequence for purification.

[0062] Embodiment 6 of the present invention provides a photocatalytic hydrogen production method, which uses the deuterated polymer 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile prepared as described above as a photocatalyst to produce hydrogen via photocatalysis.

[0063] Embodiment 7 of the present invention is a photocatalytic hydrogen production method. Based on Embodiment 6, the photocatalytic hydrogen production includes the following steps: placing a deuterated polymer 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile in a beaker, adding pure water and triethanolamine; placing the beaker in an ultrasonicator for ultrasonication to effectively disperse the deuterated polymer 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile in the liquid; pouring the liquid into a reactor filled with water to be decomposed to produce hydrogen via photocatalysis.

[0064] Embodiment 8 of the present invention is a photocatalytic hydrogen production method. Based on Embodiment 7, the reaction temperature in the reactor is 10°C, a xenon lamp light source is used to irradiate the solution in the reactor, the xenon lamp light source power is 15W and the light wavelength is greater than 420nm, and the solution in the reactor is stirred at a stirring rate of 250rpm. Specific embodiments

[0066] Preparation of deuterated 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile (D-4CzIPN);

[0067] Step 01, at room temperature and under argon atmosphere, slowly add 10 ml of tetrahydrofuran solution to 600 mg of sodium hydride (60% in oil) and 1670 mg, 10.0 mmmol of deuterated carbazole, and stir for 30 minutes;

[0068] Step 02, add 400 mg of tetrafluoroisophthalonitrile solution dissolved in 10 ml of tetrahydrofuran, and stir at room temperature in an argon atmosphere for 12 hours;

[0069] Step 03, add 2 ml of deionized water to the reaction mixture to quench the excess sodium hydride;

[0070] Step 04, under reduced pressure, concentrating the obtained mixture and washing the obtained crude product with deionized water and ethanol;

[0071] Step 05, finally purifying by recrystallization from cyclohexane or dichloromethane to obtain deuterated 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile (D-4CzIPN);

[0072] Preparation of deuterated polymer 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile (D-poly-4CzIPN);

[0073] Step 06, under an argon atmosphere, dissolving deuterated 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile in 50 ml of anhydrous chloroform to obtain a monomer solution;

[0074] Step 07, adding the monomer solution dropwise into a mixed solution of 322 mg of anhydrous ferric chloride and 100 ml of anhydrous chloroform;

[0075] Step 08, stirring the reaction mixture at room temperature for 72 hours, after the stirring was completed, adding 50 ml of methanol, stirring for 1 hour to quench the excess sodium hydride, and washing the obtained product with hydrochloric acid (12M) for 1 hour;

[0076] Step 09, filtering and washing with deionized water;

[0077] Step 10, using Soxhlet extraction method, adding tetrahydrofuran for purification for 24 hours and methanol for purification for 48 hours;

[0078] Step 11, drying at 80° C. in a vacuum atmosphere for 24 hours to obtain a deuterated polymer 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile (D-poly-4CzIPN).

[0079] Comparative Example

[0080] Preparation of 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile (4CzIPN);

[0081] Step 01, at room temperature and under argon atmosphere, slowly add 10 ml of tetrahydrofuran solution to a mixed solution of 600 mg of sodium hydride (60% in oil) and 1670 mg, 10.0 mmmol of carbazole, and stir for 30 minutes;

[0082] Step 02, add 400 mg of tetrafluoroisophthalonitrile solution dissolved in 10 ml of tetrahydrofuran, and stir at room temperature in an argon atmosphere for 12 hours;

[0083] Step 03, add 2 ml of deionized water to the reaction mixture to quench the excess sodium hydride;

[0084] Step 04, under reduced pressure, concentrating the obtained mixture and washing the obtained crude product with deionized water and ethanol;

[0085] Step 05, finally purifying by recrystallization from cyclohexane or dichloromethane to obtain 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile (4CzIPN);

[0086] Preparation of polymer 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile (poly-4CzIPN);

[0087] Step 06, under an argon atmosphere, dissolving 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile in 50 ml of anhydrous chloroform to obtain a monomer solution;

[0088] Step 07, adding the monomer solution dropwise into a mixed solution of 322 mg of anhydrous ferric chloride and 100 ml of anhydrous chloroform;

[0089] Step 08, stirring the reaction mixture at room temperature for 72 hours, after the stirring was completed, adding 50 ml of methanol, stirring for 1 hour to quench the excess sodium hydride, and washing the obtained product with hydrochloric acid (12M) for 1 hour;

[0090] Step 09, filtering and washing with deionized water;

[0091] Step 10, using Soxhlet extraction method, adding tetrahydrofuran for purification for 24 hours and methanol for purification for 48 hours;

[0092] Step 11, drying at 80° C. in a vacuum atmosphere for 24 hours to obtain a polymer 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile (poly-4CzIPN).

[0093] Photocatalytic hydrogen production was carried out in a Labsolar-6A instrument. 10 mg of the deuterated polymer 2,4,5,6-tetra(9-carbazolyl)-isophthalonitrile (D-poly-4CzIPN) catalyst prepared above was weighed and placed in a beaker. 45 mL of pure water, 5 mL of triethanolamine as a hole sacrificial agent, and 3% H2PtCl6 were added. The beaker containing the sample was placed in an ultrasonicator for 5 minutes to effectively disperse the catalyst in the liquid. After ultrasonication, the mixture was poured into the reactor, and the instrument was prepared, and then photocatalytic hydrogen production was carried out. The reaction temperature was maintained at 10°C, the xenon lamp light source power was 15W and the light wavelength was greater than 420nm, and the reactor stirring rate was 250rpm.

[0094] like Figure 2 As shown, two broad characteristic diffraction peaks were observed at 2θ=8° and 24.6° for both poly-4CzIPN and D-poly-4CzIPN, indicating that the introduction of deuterium did not cause significant changes in the polymer structure.

[0095] like Figure 3 As shown in the figure, the Fourier transform infrared spectra of poly-4CzIPN and D-poly-4CzIPN show that the -1 Up to 1200cm -1 There are several typical signals in the range, which can be attributed to the skeleton vibration of the aromatic ring; 2236cm -1 The signal at 1225 cm is attributed to the C≡N stretching mode. -1 、1454cm -1 and 1611cm -1 The characteristic peak of D-poly-4CzIPN is 20-100cm -1 The displacement of the C—H bond at 3050 cm -1 The stretching vibration at 741 cm -1 The bending vibrations at 2278 cm-1 and 2278 cm-2 after deuteration -1 and 578cm -1 . Through wavelength and energy conversion, 3050cm -1 and 741cm -1 The shift of the typical C-H bond at corresponds to an energy change of 2.2 kcal / mol and 0.5 kcal / mol, respectively. Therefore, deuterium substitution leads to a decrease in the overall stretching and bending vibration energies of poly-4CzIPN, indicating a weakening of the phonon energy of the lattice vibration energy.

[0096] like Figure 4As shown in the figure, it can be clearly seen that compared with poly-4CzIPN, the absorption wavelength of D-poly-4CzIPN has a blue shift, and the absorption intensity is slightly weakened, which is consistent with the apparent color change of the catalyst. The color of poly-4CzIPN is reddish brown, and the color of D-poly-4CzIPN after deuterium replaces hydrogen is yellowish brown.

[0097] like Figure 5 As shown, it can be seen that the band gaps of poly-4CzIPN and D-poly-4CzIPN are 2.26eV and 2.28eV respectively. The substitution of deuterium has a certain influence on the energy band structure of the catalyst.

[0098] like Figure 6 As shown in the figure, it can be clearly seen that D-poly-4CzIPN has a higher fluorescence intensity. This is because the lower vibration of the CD bond in D-poly-4CzIPN effectively prevents the non-radiative decay process, thereby significantly improving the radiative fluorescence efficiency.

[0099] like Figure 7 As shown in the figure, the fluorescence lifetime of poly-4CzIPN is 2.25ns, and the fluorescence lifetime of D-poly-4CzIPN is 2.45ns. The deuterium substitution strategy prolongs the lifetime of photogenerated carriers. The fluorescence lifetime is extended because deuterium substitution helps to significantly reduce the proton stretching frequency and phonon energy, thereby requiring a higher vibration quantum to bridge the band gap between the excited state and the ground state, resulting in a longer time for the excited state electron to relax to the ground state.

[0100] like Figure 8 As shown, it can be observed that the temperature-induced fluorescence intensity change in the D-poly-4CzIPN material is more obvious than that in the poly-4CzIPN material. The PL line width at different temperatures is extracted from the temperature-dependent fluorescence spectrum, and the Huang-Rys factor is obtained by fitting equation (1) to evaluate the electron-phonon coupling strength:

[0101]

[0102] The fitting results show that the Huang-Rys factor and phonon energy in poly-4CzIPN are 3.3 and 94.73 meV, respectively, and the Huang-Rys factor and phonon energy in D-poly-4CzIPN are 5.6 and 72.89 meV, respectively. The lower phonon energy in poly-D-4CzIPN is the result of the vibration reduction caused by the substitution of CD bonds for CH bonds, which is consistent with the FTIR results. The internal conversion between the high vibration energy level of the ground state and the low vibration energy level of the excited state in the catalyst is the main driving force for the non-radiative decay of carriers. According to Fermi's golden rule, the internal conversion rate is negatively correlated with the Huang-Rhys factor S. Therefore, the enhanced Huang-Rys factor after the deuteration process means that the internal conversion process is suppressed, that is, the non-radiative deactivation of electrons is reduced, and the carrier lifetime is extended, which leads to a higher visible light photocatalytic decomposition of water to produce hydrogen production rate, thereby achieving the effect of improving the catalyst activity.

[0103] like Fig. 9 As shown in the figure, it can be intuitively observed that D-poly-4CzIPN has a stronger hydrogen production ability. The hydrogen production rate of D-poly-4CzIPN is 2254 μmol·g -1 ·h -1 The hydrogen production rate of poly-4CzIPN was 1816 μmol·g -1 ·h -1 .

[0104] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A deuterated organic semiconductor photocatalyst, characterized in that: It is a deuterated polymer 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile, and the structural formula of the deuterated polymer 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile is as follows:

2. A method for preparing a deuterated organic semiconductor photocatalyst, characterized in that: The steps include: Preparation of deuterated 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile: Step 01, slowly add tetrahydrofuran solution to deuterated carbazole and sodium hydride, and stir; Step 02, adding tetrafluoroisophthalonitrile tetrahydrofuran solution and stirring; Step 03, adding deionized water to the reaction mixture; Step 04: under reduced pressure, the obtained mixture was concentrated, and washed with deionized water and ethanol to obtain a crude product; Step 05, the crude product is purified by recrystallization to obtain deuterated 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile; Preparation of deuterated polymer 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile; Step 06, dissolving deuterated 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile in anhydrous chloroform to obtain a monomer solution; Step 07, adding the monomer solution dropwise into a mixed solution of anhydrous ferric chloride and anhydrous chloroform; Step 08, stirring, after the stirring is completed, adding methanol, stirring, and washing the obtained product with hydrochloric acid; Step 09, filter and wash with deionized water; Step 10, purification; Step 11: drying to obtain a deuterated polymer 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile.

3. The method for preparing a deuterated organic semiconductor photocatalyst according to claim 2, characterized in that: The step 01 is performed at room temperature in an argon atmosphere.

4. The method for preparing a deuterated organic semiconductor photocatalyst according to claim 3, characterized in that: In step 05, the crude product is passivated by recrystallization from cyclohexane or dichloromethane.

5. The method for preparing a deuterated organic semiconductor photocatalyst according to claim 4, characterized in that: In step 10, Soxhlet extraction is used for purification: tetrahydrofuran and methanol are sequentially added to the product for purification.

6. A method for photocatalytic hydrogen production, using a deuterated organic semiconductor photocatalyst as claimed in claim 1, or a deuterated polymer 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile prepared by any method of claims 2 to 5 as a photocatalyst for photocatalytic hydrogen production.

7. A photocatalytic hydrogen production method according to claim 6, characterized in that: The photocatalytic hydrogen production comprises the following steps: placing a deuterated polymer 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile in a beaker, and adding pure water and triethanolamine; placing the beaker in an ultrasonicator for ultrasonication to effectively disperse the deuterated polymer 2,4,5,6-tetrakis(9-carbazolyl)-isophthalonitrile in a liquid; and pouring the liquid into a reactor filled with water to be decomposed to perform photocatalytic hydrogen production.

8. A photocatalytic hydrogen production method according to claim 7, characterized in that: The reaction temperature in the reactor is 10° C. A xenon lamp light source is used to irradiate the solution in the reactor. The xenon lamp light source has a power of 15 W and a light wavelength greater than 420 nm. The solution in the reactor is stirred at a stirring rate of 250 rpm.

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