A thiophene-alkyne bifunctional organic semiconductor and its preparation method and application

Abstract

The invention discloses a thiophene-alkynyl bifunctionalized organic semiconductor and a preparation method and application thereof, belonging to the technical field of organic semiconductor materials. The preparation method of the thiophene-alkynyl bifunctionalized organic semiconductor comprises the following steps: dissolving an organic small molecule containing thiophene and alkynyl in a polar organic solvent, acid-doping the solution, preheating the solution in air under mild conditions, adding an oxidant after preheating, and performing an oxidative coupling reaction; after the reaction is completed, naturally cooling the solution to room temperature, performing a quenching reaction, and washing, purifying, and drying the solution to obtain the thiophene-alkynyl bifunctionalized organic semiconductor. The thiophene-alkynyl bifunctionalized organic semiconductor prepared by the invention has good absorption in the visible light range, and its energy band structure meets the requirements of catalytically decomposing water to produce oxygen and hydrogen under visible light irradiation, and has the ability to photocatalytically decompose water to produce hydrogen and evolve oxygen. It also has excellent methane adsorption and storage performance, thereby improving the ability to photocatalytically convert methane into high-value-added organic chemicals.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic semiconductor materials, and in particular relates to a thiophene-alkyne bifunctional organic semiconductor and a preparation method and application thereof. Background Art

[0002] With the growing global demand for energy, the conversion of methane, a plentiful carbon source, into high-value-added liquid organic chemicals has attracted considerable attention. However, methane's extreme stability and low reactivity make its direct conversion challenging. Therefore, developing efficient catalysts and reaction systems to promote methane conversion has become a crucial research topic.

[0003] Existing methane conversion catalyst systems typically require high temperatures and pressures, or rely on additional oxidants (oxygen, hydrogen peroxide) to achieve effective methane conversion. These harsh reaction conditions not only increase energy consumption and costs, but can also lead to catalyst deactivation and reduced selectivity, limiting their feasibility for industrial application. Therefore, the development of materials that can efficiently catalyze methane conversion under mild conditions is particularly important. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a thiophene-alkyne bifunctionalized organic semiconductor and its preparation method and application, which solves the problems in the prior art.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A method for preparing a thiophene-alkyne bifunctionalized organic semiconductor comprises the following steps:

[0007] The organic small molecules containing thiophene and alkynyl groups are dissolved in a polar organic solvent, doped with acid, and then preheated in air under mild conditions. After preheating, an oxidant is added to carry out an oxidative coupling reaction.

[0008] After the reaction is completed, the temperature is naturally lowered to room temperature to quench the reaction, and the thiophene-alkynyl bifunctional organic semiconductor is obtained after washing, purification, and drying.

[0009] The general structural formula of the organic small molecule containing thiophene and alkynyl groups is:

[0010]

[0011] Here, n is an integer of 1 to 5, and m is an integer of 1 to 4.

[0012] Furthermore, the polar organic solvent includes one or more of acetonitrile, N-methylpyrrolidone, diethylene glycol butyl ether, N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N-methylformamide, dimethyl sulfoxide, dimethyl sulfone, cyclopentane, pyridine, and piperidine.

[0013] Furthermore, the doped acid includes one or more of trifluoroacetic acid, phosphoric acid, sulfuric acid, hydrochloric acid, nitric acid, nitrous acid, hydrofluoric acid, terephthalic acid, benzenesulfonic acid, formic acid, acetic acid, oxalic acid, and aminosulfonic acid.

[0014] Furthermore, the oxidant includes one or more of potassium chlorate, ammonium chloride, ammonium persulfate, ammonium nitrite, hydrogen fluoride, hydrogen peroxide, potassium permanganate, ferric chloride, silver oxide, sodium peroxide, sodium nitrite, elemental iodine, sulfur tetrafluoride, chromium oxide, manganese dioxide, copper oxide, and cuprous oxide.

[0015] Furthermore, the concentration of the organic small molecules containing thiophene and alkynyl groups dissolved in the polar organic solvent is 5-100 mM; the ratio of the organic small molecules containing thiophene and alkynyl groups to the doping acid is (5-500) mg:100 μL; the mass ratio of the organic small molecules containing thiophene and alkynyl groups to the oxidant is (5-500):100.

[0016] Furthermore, the quenching reaction is performed by adding methanol, ethanol or deionized water; and the washing is performed by using hydrochloric acid with a concentration of 0.01 to 1 mol / L and deionized water.

[0017] Furthermore, the purification adopts Soxhlet extraction method, and the extraction solvents are deionized water, tetrahydrofuran, acetonitrile and acetone in sequence.

[0018] A thiophene-alkynyl bifunctional organic semiconductor is prepared using the above-mentioned method for preparing a thiophene-alkynyl bifunctional organic semiconductor, and has the general structural formula:

[0019]

[0020] Here, n is an integer of 1 to 5, and m is an integer of 1 to 4.

[0021] The application of the above-mentioned thiophene and alkynyl bifunctional organic semiconductor in photocatalytic water decomposition to produce hydrogen and oxygen.

[0022] The application of the above-mentioned thiophene and alkynyl bifunctional organic semiconductor in photocatalytic methane conversion.

[0023] Beneficial effects of the present invention:

[0024] 1. The preparation process of the thiophene-alkyne bifunctionalized organic semiconductor of the present invention is simple, the synthesis conditions are mild, and it can be achieved by a variety of methods. The raw materials are readily available, cheap, and safe, and it has the potential for large-scale preparation;

[0025] 2. The present invention can endow the organic semiconductor material with stronger electron donor and acceptor capabilities through the dual functionalization of thiophene and alkynyl groups, thereby promoting the generation of active intermediates in the reaction.

[0026] 3. The optimized electron transfer characteristics of the present invention help enhance the stability and selectivity of the catalyst, thereby improving the efficiency of converting methane into liquid organic chemicals;

[0027] 4. The thiophene-alkyne bifunctionalized organic semiconductor prepared by the present invention has good absorption in the visible light range, and the band structure meets the requirements for catalytic complete water decomposition to produce oxygen and hydrogen under visible light irradiation, and has the ability to photocatalytically decompose water to produce hydrogen and oxygen;

[0028] 5. The energy band structure of the thiophene-alkyne bifunctionalized organic semiconductor prepared by the present invention also meets the requirements for catalyzing the reduction of oxygen to superoxide radicals under visible light irradiation, thereby achieving the ability to activate methane through superoxide radicals under visible light irradiation at room temperature and pressure, and convert methane into high-value-added formic acid, methanol and acetic acid;

[0029] 6. The thiophene-alkynyl bifunctionalized organic semiconductor prepared by the present invention can achieve highly selective conversion of methane into high-value-added formic acid in pure water at room temperature and pressure without the need for any additional oxidant;

[0030] 7. The thiophene-alkyne bifunctionalized organic semiconductor prepared by the present invention has excellent methane adsorption and storage performance, and improves the ability of photocatalytic methane conversion. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0032] Figure 1 This is a synthetic route for a thiophene and alkynyl bifunctional organic semiconductor of the present invention.

[0033] Figure 2 Schematic diagram of carbon-13 solid-state nuclear magnetic resonance characterization of thiophene-alkynyl bifunctionalized organic semiconductors obtained in Examples 1 and 2 of the present invention;

[0034] Figure 31 is the visible-near-infrared absorption spectrum of the thiophene-alkyne bifunctionalized organic semiconductor obtained in Examples 1 and 2, and the inset is its optical band gap diagram;

[0035] Figure 4 This is an electron paramagnetic resonance spectrum characterization diagram of the thiophene and alkynyl bifunctionalized organic semiconductors obtained in Examples 1 and 2 of the present invention;

[0036] Figure 5 Schematic diagram of the performance of the thiophene-alkyne bifunctionalized organic semiconductors obtained in Examples 1 and 2 of the present invention in catalyzing the complete decomposition of water to produce hydrogen and oxygen under visible light irradiation;

[0037] Figure 6 Schematic diagram of the performance of the thiophene-alkyne bifunctionalized organic semiconductor obtained in Examples 1 and 2 of the present invention for converting methane under visible light catalysis;

[0038] Figure 7 This is an in-situ diffuse reflectance infrared spectrum characterization diagram of the thiophene and alkynyl bifunctionalized organic semiconductors obtained in Examples 1 and 2 of the present invention. DETAILED DESCRIPTION

[0039] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0040] A thiophene-alkyne bifunctional organic semiconductor, the general structure of which is as follows:

[0041]

[0042] Wherein, it comprises a plurality of repeating units represented by formula (II);

[0043]

[0044] wherein n is an integer of 1 to 5, preferably an integer of 1 to 3, more preferably 1 or 2; and m is an integer of 1 to 4, preferably an integer of 1 to 3, more preferably 1. The wavy line in formula (II) represents a repeating unit or repeating segment in a thiophene-alkynyl bifunctionalized organic semiconductor, which has the same meaning as a polymer with wavy lines on both sides well known to those skilled in the art.

[0045] The preparation process of a thiophene and alkynyl bifunctional organic semiconductor is as follows:

[0046] S1, dissolving an organic small molecule containing thiophene or alkynyl groups in a polar organic solvent, doping with an acid, preheating the solvent in air under mild conditions, and then adding an oxidant to carry out an oxidative coupling reaction;

[0047] S2, after the reaction is completed, the temperature is naturally lowered to room temperature to quench the reaction, and the thiophene and alkynyl bifunctional organic semiconductor is obtained after washing, purification and drying.

[0048] Among them, the general structural formula of the organic small molecule containing thiophene and alkynyl groups is shown in formula (I):

[0049]

[0050] wherein n is an integer of 1 to 5, preferably an integer of 1 to 3, more preferably 1 or 2; m is an integer of 1 to 4, preferably an integer of 1 to 3, more preferably 1;

[0051] When m and n are both 1, the structural formula of the thiophene-alkynyl bifunctionalized organic small molecule is shown in formula (III):

[0052]

[0053] When m=2 and n=1, the structural formula of the thiophene-alkynyl bifunctionalized organic small molecule is shown in formula (IV):

[0054]

[0055] The polar organic solvent is one or more of acetonitrile, N-methylpyrrolidone, diethylene glycol butyl ether, N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N-methylformamide, dimethyl sulfoxide, dimethyl sulfone, sulfolane, pyridine, and piperidine; preferably one or more of acetonitrile, N-methylpyrrolidone, diethylene glycol butyl ether, N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N-methylformamide, dimethyl sulfoxide, dimethyl sulfone, sulfolane, pyridine, and piperidine. species; more preferably acetonitrile, N-methylpyrrolidone, diethylene glycol butyl ether, N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N-methylformamide, dimethyl sulfoxide, dimethyl sulfone, sulfolane; further preferably N-methylpyrrolidone, N,N-dimethylformamide, N,N-diethylformamide, N-methylformamide, dimethyl sulfoxide; the concentration of the thiophene and alkynyl organic small molecules dissolved in the organic solvent is preferably 5-100mM, more preferably 15-85mM, and further preferably 30-60mM.

[0056] The doped acid is an acid well known to those skilled in the art, preferably one or more of trifluoroacetic acid, phosphoric acid, sulfuric acid, hydrochloric acid, nitric acid, nitrous acid, hydrofluoric acid, terephthalic acid, benzenesulfonic acid, formic acid, acetic acid, oxalic acid, and aminosulfonic acid, more preferably phosphoric acid, sulfuric acid, hydrochloric acid, nitric acid, nitrous acid, hydrofluoric acid, terephthalic acid, benzenesulfonic acid, oxalic acid, and aminosulfonic acid, and more preferably phosphoric acid, sulfuric acid, hydrochloric acid, nitric acid, and nitrous acid; the ratio of the thiophene and alkynyl organic small molecules to the doped acid is preferably (5-500) mg:100 μL, more preferably the ratio of the thiophene and alkynyl organic small molecules to the doped acid is (30-400) mg:100 μL, and more preferably the ratio of the thiophene and alkynyl organic small molecules to the doped acid is (50-300) mg:100 μL.

[0057] The mild condition is preferably 25-85° C., more preferably 35-75° C., and even more preferably 45-65° C.; the preheating time is preferably 5-120 minutes, more preferably 20-100 minutes, and even more preferably 30-75 minutes.

[0058] The oxidant is an oxidant well known to those skilled in the art, and is preferably one or more of potassium chlorate, ammonium chloride, ammonium persulfate, ammonium nitrite, hydrogen fluoride, hydrogen peroxide, potassium permanganate, ferric chloride, silver oxide, sodium peroxide, sodium nitrite, elemental iodine, sulfur tetrafluoride, chromium oxide, manganese dioxide, copper oxide, and cuprous oxide, more preferably ammonium chloride, ammonium persulfate, ammonium nitrite, hydrogen fluoride, hydrogen peroxide, potassium permanganate, ferric chloride, silver oxide, sodium peroxide, sodium nitrite, elemental iodine, and copper oxide, and further preferably ammonium chloride, ammonium persulfate, ammonium nitrite, potassium permanganate, ferric chloride, and silver oxide; the mass ratio of the thiophene and alkynyl organic small molecules to the oxidant is (50-500):100, more preferably (30-400):100, and further preferably (50-300):100; the reaction time under the mild conditions is preferably 1-120 hours, more preferably 5-100 hours, and further preferably 12-75 hours.

[0059] When quenching the reaction, methanol, ethanol, or deionized water is preferably added, and deionized water is more preferably added to quench the reaction.

[0060] After quenching the reaction, the product is preferably washed with hydrochloric acid and deionized water; the concentration of the hydrochloric acid is preferably 0.01 to 1 mol / L, more preferably 0.1 to 0.8 mol / L, and even more preferably 0.3 to 0.6 mol / L.

[0061] After washing, the product is preferably purified by Soxhlet extraction, that is, the product is purified with an extraction solvent; impurities in the product can be extracted and removed by Soxhlet extraction with an extraction solvent; the extraction solvents used for the Soxhlet extraction are preferably deionized water, tetrahydrofuran, acetonitrile and acetone in sequence; the Soxhlet extraction time for each solvent is preferably 6 to 24 hours, more preferably 10 to 18 hours, and even more preferably 12 to 16 hours.

[0062] The drying method is preferably vacuum drying; the vacuum drying temperature is preferably 35°C to 80°C, more preferably 45°C to 70°C, and even more preferably 55°C to 65°C; the vacuum drying time is preferably 12 to 72 hours, more preferably 18 to 54 hours, and even more preferably 24 to 48 hours.

[0063] The thiophene-alkynyl bifunctionalized organic semiconductor prepared by the present invention has good absorption in the visible light range, and its energy band structure meets the requirements of catalytic complete decomposition of water to produce oxygen and hydrogen under visible light irradiation. At the same time, its energy band structure also meets the requirements of catalytic reduction of oxygen to superoxide radicals under visible light irradiation, thereby achieving the conversion of methane into high-value-added formic acid, methanol and acetic acid through activation of methane by superoxide radicals under visible light irradiation at room temperature and pressure; the selectivity of oxidizing methane to formic acid can reach 92.3%, and the concentration can reach 12mM; furthermore, the preparation method has the advantages of cheap raw materials, mild reaction conditions, simple operation and easy large-scale preparation.

[0064] The present invention prepares a thiophene-alkyne bifunctionalized organic semiconductor catalyst, and achieves visible light-induced selective conversion of methane into high-value-added liquid organic chemicals in pure water at room temperature and pressure without adding any additional oxidants. This is an inexpensive, environmentally friendly and sustainable method for the efficient and targeted conversion of methane into high-value-added liquid organic chemicals. Therefore, this series of materials shows great potential in the future field of solar energy conversion.

[0065] The present invention also provides an application of the above-mentioned thiophene-alkynyl bifunctionalized organic semiconductor in methane adsorption storage, more preferably methane adsorption storage at room temperature and pressure.

[0066] The present invention also provides an application of the above-mentioned thiophene-alkynyl bifunctional organic semiconductor in photocatalytic water decomposition to produce hydrogen and oxygen, more preferably visible light photocatalysis;

[0067] In the present invention, the photocatalytic method for producing hydrogen peroxide is preferably as follows: dispersing thiophene and alkynyl bifunctional organic semiconductors in deionized water, continuously blowing argon gas to remove the solvent and air in the container, and then sealing the container, catalyzing the complete decomposition of water to produce hydrogen and oxygen under the irradiation of visible light with a wavelength greater than 420 nm.

[0068] The present invention also provides an application of the above-mentioned thiophene-alkynyl bifunctional organic semiconductor in photocatalytic methane conversion, more preferably in visible light catalytic methane conversion under normal temperature and pressure;

[0069] In the present invention, the method for photocatalytic methane conversion is preferably as follows: dispersing thiophene and alkynyl bifunctional organic semiconductors in deionized water, continuously blowing methane to remove the solvent and air in the container, and then sealing it. Under the irradiation of visible light with a wavelength greater than 420nm, at room temperature and pressure, methane is catalyzed to convert it into high-value-added liquid formic acid, methanol and ethanol products.

[0070] The novel thiophene-alkyne bifunctionalized organic semiconductor prepared by the present invention has good absorption in the visible light range, and its energy band structure meets the requirements for catalytic complete decomposition of water to produce oxygen and hydrogen under visible light irradiation. At the same time, its energy band structure also meets the requirements for catalytic reduction of oxygen to superoxide radicals under visible light irradiation, thereby realizing the activation of methane by superoxide radicals under visible light irradiation at room temperature and pressure, and converting methane into high-value-added organic chemicals such as formic acid, methanol and acetic acid, thus realizing a method for catalyzing the conversion of methane into high-value-added organic chemicals under mild conditions.

[0071] To further illustrate the present invention, the following examples provide a detailed description of a thiophene-alkynyl bifunctionalized organic semiconductor, its preparation method, and its application. The reagents used in the following examples are all commercially available.

[0072] Example 1

[0073] like Figure 1 As shown, a method for preparing a thiophene-alkynyl bifunctionalized organic semiconductor comprises the following steps:

[0074] S1. Add 500 mg of 1,3,5-tris(2-thienylethynyl)benzene (as shown in Formula III, denoted as TTEB) to a reaction bottle containing 50 mL of N-methylpyrrolidone, slowly add 200 μL of concentrated hydrochloric acid dropwise, slowly raise the temperature to 45°C, preheat at 45°C for 30 minutes, slowly add 500 mg of ammonium persulfate, maintain at 45°C, and react for 48 hours.

[0075] S2. After the reaction is completed, the temperature is naturally lowered to room temperature, deionized water is added to quench the reaction, and the product is washed with excess dilute hydrochloric acid (0.5 mol / L) and deionized water. Then, it is purified by Soxhlet extraction. After Soxhlet extraction, it is placed in a vacuum dryer at 55°C for 24 hours to obtain a thiophene and alkynyl bifunctional organic semiconductor, which is recorded as PTTEB.

[0076] The purification method using Soxhlet extraction is as follows: the obtained product is wrapped with filter paper and placed in an extraction barrel, 180 mL of extraction solvent is added each time to a 250 mL extraction flask, and each solvent is extracted for 12 hours. The extract is not collected and treated as waste liquid. The extraction solvents are deionized water, tetrahydrofuran, acetonitrile and acetone in sequence.

[0077] Example 2

[0078] like Figure 2 As shown, a method for preparing a thiophene-alkynyl bifunctionalized organic semiconductor comprises the following steps:

[0079] S1. Add 600 mg of 1,3,5-tris(2-thienylbutadiynyl)benzene (Formula IV, denoted as TTDB) to a reaction flask containing 50 mL of N-methylpyrrolidone. Slowly add 200 μL of concentrated hydrochloric acid dropwise. Slowly raise the temperature to 45°C. Preheat at 45°C for 30 minutes, then slowly add 600 mg of ammonium persulfate. Maintain the temperature at 45°C and react for 48 hours.

[0080] S2. After the reaction is completed, the temperature is naturally lowered to room temperature, deionized water is added to quench the reaction, and the product is washed with excess dilute hydrochloric acid (0.5 mol / L) and deionized water. Then, it is purified by Soxhlet extraction. After the Soxhlet extraction is completed, it is placed in a vacuum dryer at 55°C for 24 hours to obtain a thiophene and alkynyl bifunctional organic semiconductor, which is recorded as PTTDB.

[0081] The purification method using Soxhlet extraction is as follows: the obtained product is wrapped with filter paper and placed in an extraction barrel, 180 mL of extraction solvent is added to a 250 mL extraction flask at a time, and each solvent is extracted for 12 hours. The extract is treated as waste liquid. The extraction solvents are deionized water, tetrahydrofuran, acetonitrile and acetone in sequence.

[0082] The thiophene and alkynyl bifunctional organic semiconductors obtained in Example 1 and Example 2 were analyzed by nuclear magnetic resonance, and their carbon 13 solid nuclear magnetic resonance characterization images were as follows: Figure 2 As shown by a and b in . Figure 2 The results show that the theoretical thiophene and alkynyl bifunctional organic semiconductors were indeed obtained through Examples 1 and 2.

[0083] The thiophene and alkynyl bifunctional organic semiconductors obtained in Example 1 and Example 2 were analyzed using ultraviolet-visible-near-infrared diffuse reflectance spectroscopy, and the optical band gap diagrams thereof were obtained as shown in FIG. Figure 3 As shown, Figure 3 a in the figure is the thiophene-alkynyl bifunctional organic semiconductor obtained in Example 1; Figure 3 b in the embodiment 2 is the thiophene, alkynyl bifunctional organic semiconductor. Figure 3a and b in the figure indicate that the organic semiconductors with thiophene and alkynyl bifunctionalization series have good absorption in the visible light region. The optical band gaps of PTTEB and PTTDB are 2.46 eV and 2.15 eV, respectively, indicating that they have the ability to be used as photocatalysts.

[0084] Example 3

[0085] The only difference between Example 3 and Example 1 is that the N-methylpyrrolidone in Example 1 is replaced by N,N-dimethylformamide.

[0086] Example 4

[0087] The only difference between Example 4 and Example 1 is that the ammonium persulfate in Example 1 is replaced with silver oxide.

[0088] Example 5

[0089] The only difference between Example 5 and Example 1 is that the hydrochloric acid in Example 1 is converted into nitric acid.

[0090] Example 6

[0091] 2 mg of the thiophene and alkynyl bifunctionalized organic semiconductors obtained in Examples 1 and 2 were respectively dispersed in 2 mL of ultrapure water, and 60 μL of a 0.1 M DMPO (5,5-dimethyl-1-pyrroline-N-oxide) solution was added. After thorough shaking for 10 seconds, the mixture was illuminated for 1 minute using a 300 W xenon lamp (Porphyry, PLS-SXE300, λ>420 nm) in an oxygen atmosphere at atmospheric pressure. Electron paramagnetic resonance (EPR) spectrometer (Bruker EMX plus model spectrometer) was then used to collect electron paramagnetic resonance (EPR) signals.

[0092] The electron paramagnetic resonance spectra of the thiophene and alkynyl bifunctionalized organic semiconductor free radical signals obtained in Example 1 and Example 2 collected by an electron paramagnetic resonance spectrometer are as follows: Figure 4 As shown in a and b. Figure 4 The results show that the thiophene and alkynyl bifunctionalized organic semiconductors obtained in Examples 1 and 2 can reduce oxygen to generate superoxide radicals, indicating that they have the ability to activate methane.

[0093] Example 7

[0094] Add 20 mg of the prepared thiophene and alkynyl bifunctional organic semiconductor to a sealable quartz bottle, then add 20 mL of deionized water and ultrasonically disperse for 15 minutes. Use argon gas to bubble into the dispersion at a flow rate of 0.1 liters / minute for 30 minutes to remove the air in the solvent and the container, then seal the container with a rubber stopper and sealing film, and the pressure in the bottle is one atmosphere. The container is placed under a xenon lamp light source (Porphyry, PLS-SXE300) with an intensity of 100 milliwatts / square centimeter, and a filter that only allows light with a wavelength of λ>420nm to pass through is placed at the light source emission point. The test temperature of the entire photocatalytic water decomposition to produce hydrogen and oxygen is maintained at 25±5°C.

[0095] Every hour, 1 ml of gas was extracted from the quartz bottle with a syringe, and the hydrogen and oxygen content in the gas was detected and calculated using a gas chromatograph. The total production of hydrogen and oxygen was obtained by multiplying it by the total volume of the gas in the quartz bottle. The total production was divided by the time used and the mass of the material used to calculate the unit hydrogen and oxygen production of the material.

[0096] Figure 5 a and b are the performance diagrams of the thiophene and alkynyl bifunctionalized organic semiconductors obtained in Examples 1 and 2, respectively, for complete water decomposition, hydrogen production, and oxygen evolution under visible light catalysis. Figure 5 It can be seen that the thiophene-alkynyl bifunctionalized organic semiconductors obtained in Examples 1 and 2 can catalyze the complete decomposition of water to produce hydrogen and oxygen under visible light irradiation.

[0097] Example 8

[0098] 10 mg of the prepared thiophene and alkynyl bifunctional organic semiconductor was added to a sealable quartz bottle, followed by 10 mL of deionized water and ultrasonic dispersion for 15 minutes. Methane was bubbled into the dispersion at a flow rate of 0.1 liters per minute for 30 minutes to expel the air from the solvent and the container. The container was then sealed with a rubber stopper and a sealing film. The pressure inside the bottle was one atmosphere. The container was placed under a xenon lamp light source (Porphyry, PLS-SXE300) with an intensity of 100 milliwatts per square centimeter, and a filter that only allowed light with a wavelength of λ>420 nm to pass through was placed at the light source. The test temperature for the entire photocatalytic methane conversion was maintained at 25±5°C.

[0099] Every hour, 1 ml of gas was extracted from the quartz bottle with a syringe, and the content of the gas product was detected and calculated using a gas chromatograph. The total output of the gas product was obtained by multiplying it by the total volume of the gas in the quartz bottle. The unit output of the gas product was calculated by dividing the total output by the time used and the mass of the material used.

[0100] Every hour, 0.5 ml of liquid was extracted from the quartz bottle with a syringe, and the content of the liquid product was calculated using a nuclear magnetic resonance spectrometer. The total output of the liquid product was obtained by multiplying it by the total volume of the liquid in the quartz bottle. The unit output of the liquid product was calculated by dividing the total output by the time used and the mass of the material used.

[0101] Figure 6 a and b are the performance diagrams of the thiophene and alkynyl bifunctionalized organic semiconductors obtained in Examples 1 and 2 for converting methane under visible light catalysis. Figure 6 It can be seen that the thiophene-alkynyl bifunctionalized organic semiconductors obtained in Examples 1 and 2 can catalyze the conversion of methane into high-value-added organic chemicals such as formic acid, methanol, and acetic acid under light irradiation at room temperature and pressure without the addition of any additional oxidant. Among them, the selectivity of PTTDB in the oxidation of methane to formic acid can reach 92.3%, and the concentration can reach 12 mM.

[0102] The thiophene and alkynyl bifunctional organic semiconductors obtained in Example 1 and Example 2 were analyzed by in-situ diffuse reflectance infrared spectroscopy, and their in-situ diffuse reflectance infrared spectroscopy characterization diagrams were as follows: Figure 7 As shown by a and b in . Figure 7 The results show that the thiophene and alkynyl bifunctionalized organic semiconductors obtained by Examples 1 and 2 have excellent methane adsorption and storage capabilities, and improve the ability of photocatalytic methane conversion.

[0103] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0104] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention, and such changes and modifications fall within the scope of the invention as claimed.

Claims

1. A method for preparing a thiophene-alkynyl bifunctionalized organic semiconductor, characterized in that: The following steps are involved: The organic small molecules containing thiophene and alkynyl groups are dissolved in a polar organic solvent, doped with acid, and then preheated in air under mild conditions. After preheating, an oxidant is added to carry out an oxidative coupling reaction. After the reaction is completed, the temperature is naturally lowered to room temperature to quench the reaction, and the thiophene-alkynyl bifunctional organic semiconductor is obtained after washing, purification, and drying. The general structural formula of the organic small molecule containing thiophene and alkynyl groups is: Wherein, n is an integer from 1 to 5, and m is an integer from 1 to 4; The ratio of the organic small molecules containing thiophene and alkynyl groups to the doping acid is (5-500) mg:100 μL.

2. The method for preparing a thiophene-alkynyl bifunctionalized organic semiconductor according to claim 1, characterized in that: The polar organic solvent includes one or more of acetonitrile, N-methylpyrrolidone, diethylene glycol butyl ether, N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N-methylformamide, dimethyl sulfoxide, dimethyl sulfone, sulfolane, pyridine, and piperidine.

3. The method for preparing a thiophene-alkynyl bifunctionalized organic semiconductor according to claim 1, characterized in that: The doped acid includes one or more of trifluoroacetic acid, phosphoric acid, sulfuric acid, hydrochloric acid, nitric acid, nitrous acid, hydrofluoric acid, terephthalic acid, benzenesulfonic acid, formic acid, acetic acid, oxalic acid, and aminosulfonic acid.

4. The method for preparing a thiophene-alkynyl bifunctionalized organic semiconductor according to claim 1, characterized in that: The oxidant includes one or more of ammonium persulfate, hydrogen peroxide, potassium permanganate, ferric chloride, silver oxide, elemental iodine, and copper oxide.

5. The method for preparing a thiophene-alkynyl bifunctionalized organic semiconductor according to claim 1, characterized in that: The concentration of the organic small molecules containing thiophene and alkynyl groups dissolved in the polar organic solvent is 5-100 mM; the mass ratio of the organic small molecules containing thiophene and alkynyl groups to the oxidant is (5-500):

100.

6. The method for preparing a thiophene-alkynyl bifunctionalized organic semiconductor according to claim 1, characterized in that: The quenching reaction is performed by adding methanol, ethanol or deionized water; and the washing is performed by using hydrochloric acid with a concentration of 0.01 to 1 mol / L and deionized water.

7. The method for preparing a thiophene-alkynyl bifunctionalized organic semiconductor according to claim 1, characterized in that: The purification adopts Soxhlet extraction method, and the extraction solvents are deionized water, tetrahydrofuran, acetonitrile and acetone in sequence.

8. A thiophene-alkynyl bifunctional organic semiconductor, characterized in that: The thiophene-alkynyl bifunctional organic semiconductor is prepared by the preparation method of any one of claims 1 to 7, and the general structural formula is: Here, n is an integer of 1 to 5, and m is an integer of 1 to 4.

9. Use of a thiophene-alkyne bifunctional organic semiconductor as claimed in claim 8 in photocatalytic water decomposition to produce hydrogen and oxygen.

10. Use of the thiophene-alkynyl bifunctional organic semiconductor according to claim 8 in photocatalytic methane conversion.

Images