Thiophene and alkynyl bifunctional organic semiconductor as well as preparation method and application thereof

Abstract

The invention discloses a thiophene and alkynyl bifunctional organic semiconductor and a preparation method and application thereof, and belongs to the technical field of organic semiconductor materials. The preparation method of the thiophene and alkynyl bifunctional organic semiconductor comprises the following steps: dissolving small organic molecules containing thiophene and alkynyl in a polar organic solvent, carrying out acid doping, preheating in the air under mild conditions, and adding an oxidizing agent to carry out oxidative coupling reaction after preheating; after the reaction is finished, naturally cooling to room temperature, carrying out quenching reaction, washing, purifying and drying to obtain the thiophene and alkynyl bifunctional organic semiconductor; the thiophene and alkynyl bifunctional organic semiconductor prepared by the invention has better absorption in a visible light range, an energy band structure meets the requirements of catalyzing full decomposition of water to generate oxygen and hydrogen under visible light irradiation, and the thiophene and alkynyl bifunctional organic semiconductor has the capability of photocatalytic water decomposition for hydrogen production and oxygen evolution and also has excellent methane adsorption and storage performance; and the capability of photocatalytic conversion of methane into high-added-value organic chemicals is improved.

Description

Technical Field

[0001] The 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] As global energy demand continues to grow, methane, as an abundant carbon source, has attracted much attention for its conversion into high-value-added liquid organic chemicals. The extremely high stability and extremely low reactivity of methane make its direct conversion face many challenges. Therefore, the development of efficient catalysts and reaction systems to promote methane conversion has become an important research direction.

[0003] Existing methane conversion catalyst systems usually require high temperature and high pressure conditions, or rely on additional oxidants (oxygen, hydrogen peroxide) to achieve effective methane conversion. These harsh reaction conditions not only increase energy consumption and cost, but may also lead to catalyst deactivation and reduced selectivity, limiting the feasibility of its industrial application. Therefore, it is particularly important to develop materials that can efficiently catalyze methane conversion under mild conditions. Summary of the invention

[0004] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a thiophene-alkyne bifunctionalized organic semiconductor and a preparation method and application thereof, thereby solving 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 an acid, and then preheated in air under mild conditions, and then an oxidant is added after preheating 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 1-5, and m is an integer of 1-4.

[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 doped 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 by the above-mentioned method for preparing a thiophene-alkynyl bifunctional organic semiconductor, and has a general structural formula of:

[0019]

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

[0021] The above-mentioned thiophene-alkyne bifunctional organic semiconductor is used in photocatalytic water decomposition to produce hydrogen and oxygen.

[0022] The above-mentioned thiophene and alkynyl bifunctional organic semiconductor is used for photocatalytic methane conversion.

[0023] Beneficial effects of the present invention:

[0024] 1. The preparation process of the thiophene-alkyne bifunctional organic semiconductor of the present invention is simple, the synthesis conditions are mild, it can be achieved by a variety of methods, and the raw materials are easily 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, thereby promoting the generation of active intermediates in the reaction.

[0026] 3. The optimized electron transfer characteristics of the present invention help to 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 energy band structure meets the requirements of catalytic decomposition of water to produce oxygen and hydrogen under visible light irradiation, and has the ability of photocatalytic water decomposition 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 requirement of catalyzing the reduction of oxygen into superoxide radicals under visible light irradiation, thereby realizing the ability to convert methane into high value-added formic acid, methanol and acetic acid by activating methane through superoxide radicals under visible light irradiation at room temperature and pressure;

[0029] 6. The thiophene-alkynyl bifunctionalized organic semiconductor prepared by the present invention can realize highly selective conversion of methane into high value-added formic acid in pure water at room temperature and pressure without 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 drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 It is a synthetic route map of a thiophene and alkynyl bifunctionalized organic semiconductor of the present invention.

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

[0034] Figure 3is the visible-near infrared absorption spectrum of the thiophene and alkynyl bifunctionalized organic semiconductors obtained in Example 1 and Example 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 It is a schematic diagram of the performance of thiophene and alkynyl bifunctional 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 It is a schematic diagram of the performance of the thiophene and alkynyl bifunctionalized organic semiconductors 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 be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0040] A thiophene-alkyne bifunctional organic semiconductor, the general structural formula 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; 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 a repeating fragment in a thiophene-alkynyl bifunctional 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 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 semiconductors are obtained after washing, purification and drying.

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

[0052]

[0053] When m=2 and n=1, the structural formula of the thiophene and 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 to 85° C., more preferably 35 to 75° C., and even more preferably 45 to 65° C.; the preheating time is preferably 5 to 120 minutes, more preferably 20 to 100 minutes, and even more preferably 30 to 75 minutes.

[0058] The oxidant is an oxidant well known to those skilled in the art, 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 more 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, the mass ratio is more preferably (30-400):100, and the mass ratio is more preferably (50-300):100; the reaction time under the mild conditions is preferably 1-120 hours, more preferably 5-100 hours, and more 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 by using 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 more preferably 55°C to 65°C; the vacuum drying time is preferably 12 to 72 hours, more preferably 18 to 54 hours, and more preferably 24 to 48 hours.

[0063] The thiophene and alkynyl bifunctionalized organic semiconductor prepared by the present invention has good absorption in the visible light range, and the energy band structure meets the requirement of catalytically decomposing water to produce oxygen and hydrogen under visible light irradiation. At the same time, its energy band structure also meets the requirement of catalytically reducing oxygen to superoxide free radicals under visible light irradiation, thereby realizing that methane is activated by superoxide free radicals under visible light irradiation at normal temperature and pressure to convert methane into formic acid, methanol and acetic acid with high added value; 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 thiophene-alkyne bifunctionalized organic semiconductor catalysts, and realizes the visible light catalytic selective conversion of methane into high value-added liquid organic chemicals in pure water at room temperature and pressure without adding any additional oxidant. This is a cheap, environmentally friendly and sustainable way to efficiently and directional convert methane into high value-added liquid organic chemicals. Therefore, this series of materials shows great potential in the field of future solar energy conversion.

[0065] The present invention also provides an application of the above-mentioned thiophene-alkyne 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 and alkynyl bifunctional organic semiconductor in photocatalytic water decomposition to produce hydrogen and oxygen, more preferably visible light catalysis;

[0067] In the present invention, the photocatalytic method for preparing 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 it, and catalyzing the complete decomposition of water to produce hydrogen and oxygen under the irradiation of visible light with a wavelength greater than 420nm.

[0068] The present invention also provides an application of the above-mentioned thiophene and alkynyl bifunctional organic semiconductor in photocatalytic methane conversion, more preferably visible light photocatalytic 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, and continuously blowing methane to remove the solvent and air in the container and then sealing it, and catalyzing the conversion of methane into high value-added liquid formic acid, methanol and ethanol products at room temperature and pressure under the irradiation of visible light with a wavelength greater than 420nm.

[0070] The novel thiophene and alkynyl bifunctional organic semiconductor prepared by the present invention has good absorption in the visible light range, and the energy band structure meets the requirement of catalytically decomposing water to produce oxygen and hydrogen under visible light irradiation. At the same time, its energy band structure also meets the requirement of catalytically reducing oxygen to superoxide free radicals under visible light irradiation, thereby realizing that methane is activated by superoxide free radicals under visible light irradiation at room temperature and pressure, and methane is converted into high-value-added organic chemicals such as formic acid, methanol and acetic acid, thereby realizing a method of catalyzing the conversion of methane into high-value-added organic chemicals under mild conditions.

[0071] To further illustrate the present invention, a thiophene-alkyne bifunctional organic semiconductor provided by the present invention and its preparation method and application are described in detail below in conjunction with examples. 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-alkyne bifunctionalized organic semiconductor comprises the following steps:

[0074] S1, add 500 mg of 1,3,5-tri(2-thienylethynyl)benzene (as shown in Formula III, denoted as TTEB) into a reaction bottle containing 50 mL of N-methylpyrrolidone, slowly drop 200 μL of concentrated hydrochloric acid, slowly raise the temperature to 45°C, preheat at 45°C for 30 minutes, slowly add 500 mg of ammonium persulfate, maintain 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, and then purified by Soxhlet extraction. After Soxhlet extraction, it is placed at 55°C for 24 hours in a vacuum dryer to obtain a thiophene and alkynyl bifunctional organic semiconductor, which is recorded as PTTEB.

[0076] The purification by Soxhlet extraction method 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 each time, each solvent is extracted for 12 hours, and the extract is not collected but treated as waste liquid. The extraction solvents are deionized water, tetrahydrofuran, acetonitrile and acetone, respectively.

[0077] Example 2

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

[0079] S1, add 600 mg of 1,3,5-tri(2-thiophenebutadiynyl)benzene (as shown in Formula IV, denoted as TTDB) into a reaction bottle containing 50 mL of N-methylpyrrolidone, slowly drop 200 μL of concentrated hydrochloric acid, slowly raise the temperature to 45°C, preheat at 45°C for 30 minutes, slowly add 600 mg of ammonium persulfate, maintain 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, and then purified by Soxhlet extraction. After Soxhlet extraction, it is placed at 55°C for 24 hours in a vacuum dryer to obtain a thiophene and alkynyl bifunctional organic semiconductor, which is recorded as PTTDB.

[0081] The purification by Soxhlet extraction method 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, each solvent is extracted for 12 hours, and 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 the carbon 13 solid nuclear magnetic resonance characterization images thereof were as follows: Figure 2 As shown in a and b in . Figure 2 The results show that the theoretical thiophene and alkynyl bifunctionalized 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 by 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 which is the thiophene-alkynyl bifunctional organic semiconductor obtained in Example 1; Figure 3 b in the formula is the thiophene-alkynyl bifunctional organic semiconductor obtained in Example 2. Figure 3a and b in it can 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 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 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 bifunctional organic semiconductors obtained in Example 1 and Example 2 were dispersed in 2 mL of ultrapure water, respectively, and 60 μL of 0.1 M DMPO (5,5-dimethyl-1-pyrroline-N-oxide) solution was added. After sufficient shaking for 10 seconds, the mixture was illuminated for 1 minute with a 300 W xenon lamp (Porphyra, PLS-SXE300, λ>420 nm) in an atmosphere of oxygen at atmospheric pressure, and then the electron paramagnetic resonance spectrum (EPR) signal was collected using an electron paramagnetic resonance spectrometer (Bruker EMX plus model spectrometer).

[0092] The electron paramagnetic resonance spectra obtained by using an electron paramagnetic resonance spectrometer to collect the signals of the thiophene and alkynyl bifunctionalized organic semiconductor free radicals obtained in Example 1 and Example 2 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 by Examples 1 and 2 can reduce oxygen to obtain 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 a sealing film, and the pressure in the bottle is one atmosphere. Place the container under a xenon light source (Perfect, PLS-SXE300) with an intensity of 100 milliwatts / square centimeter, and place a filter that only allows wavelengths of λ>420nm to pass through at the light source. The test temperature of the entire photocatalytic decomposition of water to produce hydrogen and oxygen is maintained at 25±5°C.

[0095] Every hour, 1 ml of gas is extracted from the quartz bottle with a syringe, and the hydrogen and oxygen content in the gas is detected and calculated using a gas chromatograph. The total output of hydrogen and oxygen can be obtained by multiplying it by the total volume of the gas in the quartz bottle. The total output is 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 for fully splitting water to produce hydrogen and oxygen under visible light catalysis. Figure 5 It can be seen that the thiophene and acetyl 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] Add 10 mg of the prepared thiophene and alkynyl bifunctional organic semiconductor to a sealable quartz bottle, then add 10 mL of deionized water and ultrasonically disperse for 15 minutes. Use methane 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, and then seal the container with a rubber stopper and a sealing film. The pressure in the bottle is one atmosphere. The container is placed under a xenon light source (Perfect, 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. The test temperature of the entire photocatalytic methane conversion is 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 materials 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 by 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 materials 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 and alkynyl bifunctionalized organic semiconductors obtained in Examples 1 and 2 can convert methane into high value-added organic chemicals such as formic acid, methanol and acetic acid by light irradiation catalysis at room temperature and pressure without adding any additional oxidant; among them, the selectivity of PTTDB in oxidizing methane to formic acid can reach 92.3% and the concentration can reach 12mM.

[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 the in-situ diffuse reflectance infrared spectroscopy characterization diagrams thereof were as follows: Figure 7 As shown in 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] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0104] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A method for preparing a thiophene-alkyne 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 an acid, and then preheated in air under mild conditions, and then an oxidant is added after preheating 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: Here, n is an integer of 1-5, and m is an integer of 1-4.

2. The method for preparing a thiophene-alkyne 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, cyclopentane, pyridine, and piperidine.

3. The method for preparing a thiophene-alkyne 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-alkyne bifunctionalized organic semiconductor according to claim 1, characterized in that: 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.

5. The method for preparing a thiophene-alkyne 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 ratio of the organic small molecules containing thiophene and alkynyl groups to the doped 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.

6. The method for preparing a thiophene-alkyne bifunctionalized organic semiconductor according to claim 1, characterized in that: The quenching reaction is performed by adding methanol, ethanol or deionized water; 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-alkyne 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-alkyne bifunctionalized 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 1-5, and m is an integer of 1-4.

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-alkyne bifunctional organic semiconductor according to claim 8 in photocatalytic methane conversion.

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