Preparation method of all-organic ionic liquid confinement nano catalytic material and application of all-organic ionic liquid confinement nano catalytic material in photocatalytic CO2 methanation
By using all-organic ionic liquid confined nanocatalytic materials, and taking advantage of the synergistic effect of COF ordered channels and ionic liquids, the problems of difficult morphology and pore structure control and the use of precious metals in existing photocatalytic materials have been solved, achieving efficient and selective CO2 reduction to CH4.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HEILONGJIANG UNIV
- Filing Date
- 2026-02-09
- Publication Date
- 2026-05-19
AI Technical Summary
Existing photocatalytic materials suffer from small specific surface area and insufficient active sites due to difficulties in controlling microstructure and pore structure. They also rely on noble metals/transition metals, resulting in high costs and environmental and biological toxicity. Consequently, the selectivity and yield of photocatalytic CO2 reduction to CH4 are not ideal.
By employing all-organic ionic liquid confined nanocatalytic materials, the efficient transport and enrichment of reactants are achieved through the ordered channels of COF. The ionic liquid constructs a local high-concentration CO2 microenvironment, and the separation and migration of photogenerated carriers are regulated through the synergistic effect of the ionic liquid and the COF framework, stabilizing the key intermediate for the reduction of CO2 to CH4, thus achieving precise control of the reaction pathway.
In a pure water system, the CH4 generation rate can reach 37.6 μmol g⁻¹ h⁻¹, with a selectivity of up to 93%. The material does not require precious metals, is environmentally friendly, and has good photostability.
Smart Images
Figure CN122057564A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of photocatalytic materials technology, specifically relating to a method for preparing an all-organic ionic liquid confined nanocatalytic material and its application in photocatalytic CO2 methanation. Background Technology
[0002] Photocatalytic CO2 reduction technology utilizes solar energy to convert CO2 into high-value fuels and chemicals (such as carbon monoxide, methanol, methane, and ethylene), and is one of the effective ways to achieve carbon neutrality and renewable energy storage. Among these, methane (CH4) is particularly valuable due to its high energy density (55.5 MJ / kg⁻¹). -1 Solar fuel is considered an ideal "solar fuel".
[0003] However, the photocatalytic reduction of CO2 to CH4 is a complex multi-step reaction involving 8 electrons / 8 protons, with slow kinetics and often competing with side reaction pathways for the formation of CO and H2. This leads to bottlenecks in most catalytic systems, resulting in low CH4 selectivity and insufficient yield. For example, the Chinese patent CN 116273059 B, published on May 10, 2024, entitled "Photocatalytic Material for High-Selectivity Photoreduction of Carbon Dioxide to Methane, Preparation Method and Application Thereof," discloses a photocatalytic material for the photoreduction of carbon dioxide to methane, its preparation method and application. The catalyst prepared by this method has a methane yield of only 12.4 μmol g. -1 h -1 Furthermore, the selective generation of CH4 requires loading with the noble metal Au, which is costly and limits its potential for large-scale application. Currently reported photocatalytic CO2 reduction materials for selective CH4 production generally suffer from the following problems:
[0004] 1. It relies on precious metals (such as Au, Pt, etc.) or transition metals as active sites, which is costly and poses potential biological and environmental toxicity.
[0005] 2. The morphology and pore structure of inorganic semiconductor materials (such as oxides and sulfides) are difficult to control, with limited specific surface area and insufficient active sites, which restricts the mass transfer of reactants and the stability of intermediates.
[0006] 3. Currently, the catalyst system has a low CO2 conversion rate, and the yield and selectivity of the reduction product CH4 are not ideal. Summary of the Invention
[0007] The purpose of this invention is to address the problems of existing photocatalytic materials, such as small specific surface area and insufficient active sites due to difficulties in controlling the microstructure and pore structure, and environmental and biological toxicity caused by dependence on noble metals / transition metals, which restrict the photocatalytic reduction of CO2 to CH4. The invention provides a method for preparing an all-organic ionic liquid confined nanocatalytic material and its application in photocatalytic CO2 methanation.
[0008] A method for preparing an all-organic ionic liquid confined nanocatalytic material is specifically carried out according to the following steps:
[0009] I. Preparation of 5,5'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dipyridaldehyde:
[0010] ① 5-Bromopyridine-2-carboxaldehyde and 2,1,3-benzothiadiazole-4,7-bis(pinacol borate) were ultrasonically dispersed and dissolved in N,N-dimethylformamide to obtain solution A;
[0011] ② Disperse palladium acetate and sodium carbonate in water using ultrasonication to obtain solution B;
[0012] ③ Under a nitrogen atmosphere, solution A was added dropwise to solution B, and the mixture was heated, stirred, and refluxed. After the reaction was completed, the product was purified by silica gel column chromatography to obtain 5,5'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dipyridaldehyde.
[0013] II. Preparation of pyridine tricarboxylic acid salt ionic liquids:
[0014] Pyridine-2,4,6-tricarboxylic acid and a bromide-containing liquid were dissolved in methanol and heated under nitrogen atmosphere with stirring and reflux. After the reaction was completed, the reaction was quenched with ultrapure water, and then extracted with ethyl acetate, rotary evaporated, and freeze-dried to obtain pyridine tricarboxylic acid liquid.
[0015] The bromide-containing ionic liquid mentioned in step two is 1-methylpyridinium bromide, 1-ethyl-3-methylbromoimidazole, tetraethylammonium bromide, or tetraethylphosphine bromide;
[0016] III. Preparation of PTZpy:
[0017] ① Add the monomeric compound and 5,5'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dipyridaldehyde to a Schroeder vacuum tube, then add o-dichlorobenzene, n-butanol and acetic acid solution, and sonicate to obtain a mixed solution;
[0018] The monomeric compound mentioned in step 3① is 1,3,6,8-tetra-(p-aminophenyl)-pyrene or 1,3,5-tris(p-formylphenyl)benzene;
[0019] ② Add the mixed solution to a Schroeder vacuum tube, freeze it with liquid nitrogen for 2 min, then evacuate it into a vacuum, and then slowly thaw it at room temperature.
[0020] ③ Repeat step 3.2 three to five times, seal and heat to react. After the reaction is complete, centrifuge to collect the solid product, then wash, extract, and vacuum dry to obtain PTZpy;
[0021] IV. Preparation of PTZpy(+):
[0022] PTZpy was dispersed in N,N-dimethylformamide, methyl bromide was added under a nitrogen atmosphere, the reaction was stirred at room temperature, the solid product was collected by centrifugation, washed, and dried under vacuum to obtain PTZpy(+);
[0023] V. Preparation of IL@PTZpy(+) nanocatalytic materials:
[0024] PTZpy(+) was dispersed in an alcohol solvent, then pyridine tricarboxylic acid salt ionic liquid was added, stirred, and then vacuum dried to remove the alcohol solvent, yielding IL@PTZpy(+), which is an all-organic ionic liquid confined nanocatalytic material.
[0025] Application of all-organic ionic liquid confined nanocatalytic materials in the photocatalytic reduction of carbon dioxide to methane under visible light irradiation and pure water system.
[0026] The principle of this invention:
[0027] This invention utilizes the ordered pores of COF to achieve efficient transport and enrichment of reactants, and leverages the properties of ionic liquids to construct a localized high-concentration CO2 microenvironment. Simultaneously, through the synergistic effect of the ionic liquid and the COF framework, the separation and migration behavior of photogenerated carriers is regulated, effectively suppressing their recombination. Furthermore, the nano-confining effect and the activation ability of the ionic liquid stabilize key intermediates in the CO2 reduction to CH4 process, precisely controlling the reaction pathway, and ultimately achieving a synergistic improvement in the selectivity and yield of photocatalytic CO2 reduction to CH4.
[0028] Advantages of this invention:
[0029] 1. All-organic system: No metal active sites are required, avoiding the use of precious metals, reducing costs and improving the biocompatibility and environmental friendliness of materials;
[0030] II. Precise and controllable structure: COF ordered channels are used as nanoreactors to achieve efficient transport and enrichment of reactants, and ionic liquids are used to construct local high-concentration CO2 microenvironments;
[0031] III. Synergistic Catalytic Mechanism: The ionic liquid and the COF framework synergistically promote photogenerated charge separation and inhibit recombination, and stabilize key intermediates for CO2 reduction through confinement effect, significantly improving CH4 selectivity and yield;
[0032] IV. High catalytic performance: In a pure water system under visible light irradiation, the CH4 formation rate can reach 37.6 μmol g. -1 h -1 It has a selectivity of up to 93% and good photostability. Attached Figure Description
[0033] Figure 1 X-ray powder diffraction pattern of the all-organic ionic liquid confined nanocatalyst material prepared in Example 1;
[0034] Figure 2 The infrared spectrum of the all-organic ionic liquid confined nanocatalytic material prepared in Example 1;
[0035] Figure 3 Comparison of photocatalytic carbon dioxide reduction performance of all-organic ionic liquid confined nanocatalysts prepared for PTZpy, PTZpy(+), Examples 1, 7-10;
[0036] Figure 4 Photocatalytic cycling experiment of the all-organic ionic liquid confined nanocatalytic material prepared in Example 1. Detailed Implementation
[0037] Specific Implementation Method 1: This implementation method is a preparation method of an all-organic ionic liquid confined nanocatalytic material, which is specifically completed according to the following steps:
[0038] I. Preparation of 5,5'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dipyridaldehyde:
[0039] ① 5-Bromopyridine-2-carboxaldehyde and 2,1,3-benzothiadiazole-4,7-bis(pinacol borate) were ultrasonically dispersed and dissolved in N,N-dimethylformamide to obtain solution A;
[0040] ② Disperse palladium acetate and sodium carbonate in water using ultrasonication to obtain solution B;
[0041] ③ Under a nitrogen atmosphere, solution A was added dropwise to solution B, and the mixture was heated, stirred, and refluxed. After the reaction was completed, the product was purified by silica gel column chromatography to obtain 5,5'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dipyridaldehyde.
[0042] II. Preparation of pyridine tricarboxylic acid salt ionic liquids:
[0043] Pyridine-2,4,6-tricarboxylic acid and a bromide-containing liquid were dissolved in methanol and heated under nitrogen atmosphere with stirring and reflux. After the reaction was completed, the reaction was quenched with ultrapure water, and then extracted with ethyl acetate, rotary evaporated, and freeze-dried to obtain pyridine tricarboxylic acid liquid.
[0044] The bromide-containing ionic liquid mentioned in step two is 1-methylpyridinium bromide, 1-ethyl-3-methylbromoimidazole, tetraethylammonium bromide, or tetraethylphosphine bromide;
[0045] III. Preparation of PTZpy:
[0046] ① Add the monomeric compound and 5,5'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dipyridaldehyde to a Schroeder vacuum tube, then add o-dichlorobenzene, n-butanol and acetic acid solution, and sonicate to obtain a mixed solution;
[0047] The monomeric compound mentioned in step 3① is 1,3,6,8-tetra-(p-aminophenyl)-pyrene or 1,3,5-tris(p-formylphenyl)benzene;
[0048] ② Add the mixed solution to a Schroeder vacuum tube, freeze it with liquid nitrogen for 2 min, then evacuate it into a vacuum, and then slowly thaw it at room temperature.
[0049] ③ Repeat step 3.2 three to five times, seal and heat to react. After the reaction is complete, centrifuge to collect the solid product, then wash, extract, and vacuum dry to obtain PTZpy;
[0050] IV. Preparation of PTZpy(+):
[0051] PTZpy was dispersed in N,N-dimethylformamide, methyl bromide was added under a nitrogen atmosphere, the reaction was stirred at room temperature, the solid product was collected by centrifugation, washed, and dried under vacuum to obtain PTZpy(+);
[0052] V. Preparation of IL@PTZpy(+) nanocatalytic materials:
[0053] PTZpy(+) was dispersed in an alcohol solvent, then pyridine tricarboxylic acid salt ionic liquid was added, stirred, and then vacuum dried to remove the alcohol solvent, yielding IL@PTZpy(+), which is an all-organic ionic liquid confined nanocatalytic material.
[0054] This embodiment confines a functional ionic liquid within the pores of a covalent organic framework (COF) to construct an ionic liquid-confined nanoreactor, resulting in an all-organic nanoreactor with highly ordered pores and a localized catalytic microenvironment. Specifically, this invention synthesizes tetraphenylpyrene-thiazolylpyridine COF (PTZpy) via a solvothermal method, then introduces a positive charge at its pyridine N site through a quaternization reaction to obtain an ionized PTZpy(+) support; finally, through capillary action and ion interaction, the prepared pyridine tricarboxylic acid salt ionic liquid is confined within the mesopores of PTZpy(+) to obtain an IL@PTZpy(+) all-organic photocatalytic nanoreactor. This material exhibits excellent selective CO2 photocatalytic reduction performance in a pure water system and under visible light irradiation, with a CH4 generation rate reaching 37.6 μmol g. -1 h -1 The product selectivity is as high as 93.0%.
[0055] This embodiment achieves highly efficient photocatalytic synthesis of CH4 that is entirely organic, and has the advantages of controllable structure, environmental friendliness, and high selectivity. It has good application prospects in the fields of solar fuel preparation and carbon resource conversion.
[0056] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in the following ways: the mass ratio of 5-bromopyridine-2-carboxaldehyde and 2,1,3-benzothiadiazole-4,7-bis(pinacol ester borate) in step one ① is (0.5~1):(0.53~1.06); the mass ratio of 5-bromopyridine-2-carboxaldehyde to N,N-dimethylformamide in step one ① is (0.5g~1g):(20mL~40mL); the mass-volume ratio of palladium acetate, sodium carbonate, and water in step one ② is (0.02g~0.04g):(1g~2g):(20mL~40mL). All other steps are the same as in Specific Implementation Method One.
[0057] Specific Implementation Method 3: This implementation method differs from Specific Implementation Method 1 or 2 in the following ways: the volume ratio of solution A to solution B in step 1.3 is 1:1; the heating, stirring, and reflux temperature in step 1.3 is 60℃~70℃, and the heating, stirring, and reflux time is 40h~50h; the eluent used for purifying the product by silica gel column chromatography after the reaction in step 1.3 is a mixed solution of petroleum ether and ethyl acetate in a volume ratio of 1:(0.8~1). Other steps are the same as in Specific Implementation Method 1 or 2.
[0058] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in the following ways: the mass ratio of pyridine-2,4,6-tricarboxylic acid and bromide-containing liquid in step two is (0.14~0.28):(0.37~0.69); the mass ratio of pyridine-2,4,6-tricarboxylic acid to methanol in step two is (0.14g~0.28g):(80mL~120mL); the heating, stirring, and reflux temperature in step two is 80℃~90℃, and the heating, stirring, and reflux time is 40h~50h. Other steps are the same as in Specific Implementation Methods One to Three.
[0059] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in the following ways: the mass ratio of the monomer compound and 5,5'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dipyridaldehyde in step three① is (13~15):(10~12); the concentration of the acetic acid solution in step three① is 6 mol / L; the mass ratio of o-dichlorobenzene, n-butanol, and acetic acid solution in step three① is 1:1:0.2; and the ultrasonic treatment time in step three① is 20 min to 40 min. Other steps are the same as in Specific Implementation Methods One to Four.
[0060] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that: the mass ratio of 5,5'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dipyridinaldehyde to o-dichlorobenzene in step three ① is (13mg~15mg):1mL; in step three ③, step three ② is cyclically repeated three to five times, and after sealing, the reaction is heated at 110℃~120℃ for 70h~72h. After the reaction, the solid product is collected by centrifugation, washed 2 to 4 times each with N,N-dimethylformamide and methanol, and then extracted with N,N-dimethylformamide and methanol respectively. Finally, it is vacuum dried at 80℃ for 10h~12h. Other steps are the same as in Specific Implementation Methods One to Five.
[0061] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in the following ways: the mass-to-volume ratio of PTZpy, methyl bromide, and N,N-dimethylformamide in step four is (0.03g~0.08g):(0.02g~0.04g):90mL; the stirring time at room temperature in step four is 20h~24h; the washing in step four involves washing 3 to 5 times with anhydrous ethanol; the vacuum drying temperature in step four is 60℃~80℃, and the vacuum drying time is 10h~12h. Other steps are the same as in Specific Implementation Methods One to Six.
[0062] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in the following ways: the alcohol solvent mentioned in step five is methanol, ethanol, propanol, isopropanol, or butanol; the mass ratio of PTZpy(+) to pyridine tricarboxylic acid salt ionic liquid in step five is 0.05 g:(2.5 mg~12.5 mg); the mass ratio of PTZpy(+) to alcohol solvent in step five is 0.05 g:(3 mL~6 mL); the stirring time in step five is 1 h~2 h; and the vacuum drying temperature in step five is 60℃~80℃. Other steps are the same as in Specific Implementation Methods One to Seven.
[0063] Specific Implementation Method Nine: This implementation method is the application of all-organic ionic liquid confined nanocatalytic materials in the photocatalytic reduction of carbon dioxide to methane under visible light irradiation and pure water system.
[0064] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Methods One through Nine in that: the photocatalytic reduction of carbon dioxide to methane by the all-organic ionic liquid confined nanocatalytic material under visible light irradiation and a pure water system is carried out according to the following steps:
[0065] The all-organic ionic liquid confined nanocatalytic material powder was dispersed in ultrapure water, and then the mixed solution was placed in a quartz reactor. After sealing the system, it was magnetically stirred. CO2 gas was bubbled through to purge the air in the device and reach adsorption equilibrium. At the same time, the cooling water was turned on to ensure that the reaction temperature was maintained at 20°C, and then the reactor was sealed. A 300W xenon lamp was used to simulate the sunlight and irradiated the reactor from the top during the catalytic reaction. The wavelength of the incident light was controlled by a filter. At fixed intervals, the generated products were detected using a photocatalytic gas chromatography detection system. CO and CH4 could be detected in the FID2 channel, and H2 and O2 could be detected in the TCD channel. Other steps were the same as in specific implementation methods one through nine.
[0066] The beneficial effects of the present invention are verified using the following embodiments:
[0067] Example 1: A method for preparing an all-organic ionic liquid confined nanocatalytic material, specifically carried out according to the following steps:
[0068] I. Preparation of 5,5'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dipyridaldehyde:
[0069] ① 5-Bromopyridine-2-carboxaldehyde and 2,1,3-benzothiadiazole-4,7-bis(pinacol borate) were ultrasonically dispersed and dissolved in N,N-dimethylformamide to obtain solution A;
[0070] The mass ratio of 5-bromopyridine-2-carboxaldehyde and 2,1,3-benzothiadiazole-4,7-bis(pinacol ester borate) mentioned in step 1① is 0.74g:0.78g;
[0071] The mass ratio of 5-bromopyridine-2-carboxaldehyde to the volume ratio of N,N-dimethylformamide in step 1① is 0.74 g: 30 mL;
[0072] ② Disperse palladium acetate and sodium carbonate in water using ultrasonication to obtain solution B;
[0073] The mass-to-volume ratio of palladium acetate, sodium carbonate, and water mentioned in step 1② is 0.03g:1.60g:30mL;
[0074] ③ Under a nitrogen atmosphere, solution A was added dropwise to solution B, and the mixture was stirred and refluxed at 60°C for 48 hours. After the reaction was completed, the product was purified by silica gel column chromatography to obtain 5,5'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dipyridaldehyde.
[0075] The volume ratio of solution A to solution B mentioned in step 1③ is 1:1;
[0076] In step 1, ③, after the reaction is completed, the product is purified by silica gel column chromatography using a mixed solution of petroleum ether and ethyl acetate in a volume ratio of 1:1.
[0077] II. Preparation of pyridine tricarboxylic acid salt ionic liquids:
[0078] 0.21 g of pyridine-2,4,6-tricarboxylic acid and a bromide-containing liquid were dissolved in 100 mL of methanol. The mixture was stirred and refluxed at 80 °C for 48 h under a nitrogen atmosphere. After the reaction was completed, the reaction was quenched with ultrapure water, and then extracted with ethyl acetate, rotary evaporated, and freeze-dried to obtain the pyridine tricarboxylic acid liquid.
[0079] The bromide-containing liquid mentioned in step two is 0.52 g of 1-methylpyridinium bromide;
[0080] III. Preparation of PTZpy:
[0081] ① Add the monomer compound and 5,5'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dipyridaldehyde to a Schroeder vacuum tube, then add o-dichlorobenzene, n-butanol and acetic acid solution, and sonicate for 30 min to obtain a mixed solution;
[0082] The monomeric compound mentioned in step 3① is 1,3,6,8-tetra-(p-aminophenyl)-pyrene;
[0083] The mass ratio of 5,5'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dipyridaldehyde and the monomer compound in step 3① is 14.2 mg: 11.3 mg;
[0084] The concentration of the acetic acid solution mentioned in step 3① is 6 mol / L;
[0085] The volume ratio of the o-dichlorobenzene, n-butanol, and acetic acid solution mentioned in step 3① is 1 mL: 1 mL: 0.2 mL;
[0086] The mass ratio of 5,5'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dipyridaldehyde to o-dichlorobenzene in step 3① is 14.2 mg: 1 mL;
[0087] ② Add the mixed solution to a Schroeder vacuum tube, freeze it with liquid nitrogen for 2 minutes, then evacuate it into a vacuum, and then slowly thaw it at room temperature.
[0088] ③ Repeat step 3.2 three times, seal and heat at 120℃ for 72h. After the reaction is completed, centrifuge to collect the solid product, wash with N,N-dimethylformamide and methanol three times each, then extract with N,N-dimethylformamide and methanol respectively, and finally vacuum dry at 80℃ for 12h to obtain PTZpy.
[0089] IV. Preparation of PTZpy(+):
[0090] PTZpy was dispersed in N,N-dimethylformamide, and methyl bromide was added under a nitrogen atmosphere. The mixture was stirred at room temperature for 24 h, and the solid product was collected by centrifugation. The product was washed three times with anhydrous ethanol and dried under vacuum at 80 °C for 12 h to obtain PTZpy(+).
[0091] The mass-to-volume ratio of PTZpy, methyl bromide, and N,N-dimethylformamide mentioned in step four is 0.05 g: 0.03 g: 90 mL;
[0092] V. Preparation of IL@PTZpy(+) nanocatalytic materials:
[0093] PTZpy(+) was dispersed in methanol, then pyridine tricarboxylic acid salt ionic liquid was added, stirred for 1 h, and then vacuum dried at 80 °C to remove the alcohol solvent, to obtain IL@PTZpy(+), which is the all-organic ionic liquid confined nanocatalytic material (denoted as 20IL@PTZpy(+)).
[0094] The mass ratio of PTZpy(+) to pyridine tricarboxylic acid ionic liquid in step five is 0.05 g: 10 mg;
[0095] The mass ratio of PTZpy(+) to methanol in step five is 0.05 g: 5 mL.
[0096] The reaction formula for step one of Example 1:
[0097] ;
[0098] The reaction formula for step two of Example 1:
[0099] ;
[0100] The reaction formula for step three of Example 1:
[0101] ;
[0102] The reaction formula for step four of Example 1:
[0103] ;
[0104] The reaction formula for step five of Example 1:
[0105] .
[0106] The PTZpy, PTZpy(+), and IL@PTZpy(+) obtained in Example 1 were subjected to X-ray powder diffraction and infrared spectroscopy tests, see [see details]. Figure 1 and Figure 2 As shown;
[0107] Figure 1 and Figure 2 The synthesis of COF materials and the successful confinement of IL were confirmed.
[0108] Example 2: The difference between this example and Example 1 is that the bromide-containing liquid in step two is 0.57g of 1-ethyl-3-methylbromoimidazole. All other steps and parameters are the same as in Example 1.
[0109] Example 3: The difference between this example and Example 1 is that the bromide-containing liquid mentioned in step two is 0.63g of tetraethylammonium bromide. All other steps and parameters are the same as in Example 1.
[0110] Example 4: The difference between this example and Example 1 is that the bromide-containing liquid mentioned in step two is 0.68g of tetraethylphosphine bromide. All other steps and parameters are the same as in Example 1.
[0111] Example 5: The difference between this example and Example 1 is that the monomer compound mentioned in step 3① is 1,3,5-tris(p-formylphenyl)benzene. All other steps and parameters are the same as in Example 1.
[0112] Example 6: The difference between this example and Example 1 is that methyl bromide in step four is replaced with ethyl bromide. All other steps and parameters are the same as in Example 1.
[0113] Example 7: The difference between this example and Example 1 is that the mass ratio of PTZpy(+) to pyridine tricarboxylic acid ionic liquid in step five is 0.05 g: 2.5 mg; the all-organic ionic liquid confined nanocatalytic material obtained in step five is denoted as 5 IL@PTZpy(+). All other steps and parameters are the same as in Example 1.
[0114] Example 8: The difference between this example and Example 1 is that the mass ratio of PTZpy(+) to pyridine tricarboxylic acid ionic liquid in step five is 0.05 g: 5 mg; the all-organic ionic liquid confined nanocatalytic material obtained in step five is denoted as 10 IL@PTZpy(+). All other steps and parameters are the same as in Example 1.
[0115] Example 9: The difference between this example and Example 1 is that the mass ratio of PTZpy(+) to pyridine tricarboxylic acid ionic liquid in step five is 0.05 g: 7 mg; the all-organic ionic liquid confined nanocatalytic material obtained in step five is denoted as 15 IL@PTZpy(+). All other steps and parameters are the same as in Example 1.
[0116] Example 10: The difference between this example and Example 1 is that the mass ratio of PTZpy(+) to pyridine tricarboxylic acid ionic liquid in step five is 0.05 g: 12.5 mg; the all-organic ionic liquid confined nanocatalytic material obtained in step five is denoted as 25 IL@PTZpy(+). All other steps and parameters are the same as in Example 1.
[0117] Application Examples:
[0118] 20 mg of catalyst was dispersed in 10 mL of ultrapure water. The mixture was then placed in a 100 mL cylindrical quartz reactor, sealed, and uniformly dispersed under magnetic stirring at 300 rpm. 99.9% pure CO2 gas was bubbled through at a flow rate of 150 mL / min. -1 The air in the device was purged for 30 minutes to reach adsorption equilibrium, while the condenser was turned on to maintain the reaction temperature at 20°C. The reactor was then sealed. A 300W xenon lamp (PLS-SXE300) was used to simulate sunlight, illuminating the reactor from the top during the catalytic reaction. The wavelength of the incident light was controlled by a filter (λ > 420nm). The generated products were detected at fixed intervals using a photocatalytic gas chromatography system (HF-901A). CO and CH4 were detected in the FID2 channel; H2 and O2 were detected in the TCD channel.
[0119] Figure 3 Comparison of photocatalytic carbon dioxide reduction performance of all-organic ionic liquid confined nanocatalysts prepared for PTZpy, PTZpy(+), Examples 1, 7-10;
[0120] from Figure 3 It was found that the proportion of CH4 in the reduction products of the photocatalyst gradually increased with the increase of the amount of confined ionic liquid (pyridine tricarboxylic acid salt ionic liquid). However, further increasing the proportion of IL (25%) led to pore blockage, thereby hindering mass transfer and causing performance degradation. The 20IL@PTZpy(+) prepared in Example 1 achieved the highest CH4 release rate of 37.6 μmol g. -1 h -1 At the same time, it effectively suppressed the byproduct CO (1.6 μmol g). -1 h -1 The generation of ) corresponds to a CH4 product selectivity of 93.5%.
[0121] Figure 4 Photocatalytic cycling experiment of the all-organic ionic liquid confined nanocatalytic material prepared in Example 1;
[0122] from Figure 4It can be seen that the activity and selectivity of the 20IL@PTZpy(+) prepared in Example 1 remained almost unchanged during ten consecutive runs, which proves the reusability of the photocatalyst.
Claims
1. A method for preparing an all-organic ionic liquid confined nanocatalytic material, characterized in that... The preparation method is specifically carried out according to the following steps: I. Preparation of 5,5'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dipyridaldehyde: ① 5-Bromopyridine-2-carboxaldehyde and 2,1,3-benzothiadiazole-4,7-bis(pinacol borate) were ultrasonically dispersed and dissolved in N,N-dimethylformamide to obtain solution A; ② Disperse palladium acetate and sodium carbonate in water using ultrasonication to obtain solution B; ③ Under a nitrogen atmosphere, solution A was added dropwise to solution B, and the mixture was heated, stirred, and refluxed. After the reaction was completed, the product was purified by silica gel column chromatography to obtain 5,5'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dipyridaldehyde. II. Preparation of pyridine tricarboxylic acid salt ionic liquids: Pyridine-2,4,6-tricarboxylic acid and a bromide-containing liquid were dissolved in methanol and heated under nitrogen atmosphere with stirring and reflux. After the reaction was completed, the reaction was quenched with ultrapure water, and then extracted with ethyl acetate, rotary evaporated, and freeze-dried to obtain pyridine tricarboxylic acid liquid. The bromide-containing ionic liquid mentioned in step two is 1-methylpyridinium bromide, 1-ethyl-3-methylbromoimidazole, tetraethylammonium bromide, or tetraethylphosphine bromide; III. Preparation of PTZpy: ① Add the monomeric compound and 5,5'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dipyridaldehyde to a Schroeder vacuum tube, then add o-dichlorobenzene, n-butanol and acetic acid solution, and sonicate to obtain a mixed solution; The monomeric compound mentioned in step 3① is 1,3,6,8-tetra-(p-aminophenyl)-pyrene or 1,3,5-tris(p-formylphenyl)benzene; ② Add the mixed solution to a Schroeder vacuum tube, freeze it with liquid nitrogen for 2 min, then evacuate it into a vacuum, and then slowly thaw it at room temperature. ③ Repeat step 3.2 three to five times, seal and heat the reaction. After the reaction is complete, centrifuge to collect the solid product, then wash, extract, and vacuum dry to obtain PTZpy; IV. Preparation of PTZpy(+): PTZpy was dispersed in N,N-dimethylformamide, methyl bromide was added under a nitrogen atmosphere, the reaction was stirred at room temperature, the solid product was collected by centrifugation, washed, and dried under vacuum to obtain PTZpy(+); V. Preparation of IL@PTZpy(+) nanocatalytic materials: PTZpy(+) was dispersed in an alcohol solvent, then pyridine tricarboxylic acid salt ionic liquid was added, stirred, and then vacuum dried to remove the alcohol solvent, yielding IL@PTZpy(+), which is an all-organic ionic liquid confined nanocatalytic material.
2. The method for preparing an all-organic ionic liquid confined nanocatalytic material according to claim 1, characterized in that... The mass ratio of 5-bromopyridine-2-carboxaldehyde and 2,1,3-benzothiadiazole-4,7-bis(pinacol ester borate) in step 1① is (0.5~1):(0.53~1.06); the mass ratio of 5-bromopyridine-2-carboxaldehyde to N,N-dimethylformamide in step 1① is (0.5g~1g):(20mL~40mL); the mass-volume ratio of palladium acetate, sodium carbonate and water in step 1② is (0.02g~0.04g):(1g~2g):(20mL~40mL).
3. The method for preparing an all-organic ionic liquid confined nanocatalytic material according to claim 1, characterized in that... The volume ratio of solution A to solution B in step 1③ is 1:1; the heating, stirring and reflux temperature in step 1③ is 60℃~70℃, and the heating, stirring and reflux time is 40h~50h; the eluent used for purifying the product by silica gel column chromatography after the reaction in step 1③ is a mixed solution of petroleum ether and ethyl acetate in a volume ratio of 1:(0.8~1).
4. The method for preparing an all-organic ionic liquid confined nanocatalytic material according to claim 1, characterized in that... The mass ratio of pyridine-2,4,6-tricarboxylic acid and bromide-containing liquid in step two is (0.14~0.28):(0.37~0.69); the mass ratio of pyridine-2,4,6-tricarboxylic acid to methanol in step two is (0.14g~0.28g):(80mL~120mL); the heating, stirring and reflux temperature in step two is 80℃~90℃, and the heating, stirring and reflux time is 40h~50h.
5. The method for preparing an all-organic ionic liquid confined nanocatalytic material according to claim 1, characterized in that... The mass ratio of the monomeric compound and 5,5'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dipyridaldehyde in step 3① is (13~15):(10~12); the concentration of the acetic acid solution in step 3① is 6 mol / L; the mass ratio of o-dichlorobenzene, n-butanol and acetic acid solution in step 3① is 1:1:0.2; and the ultrasonic treatment time in step 3① is 20 min~40 min.
6. The method for preparing an all-organic ionic liquid confined nanocatalytic material according to claim 1, characterized in that... In step 3①, the mass ratio of 5,5'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dipyridinaldehyde to o-dichlorobenzene is (13mg~15mg):1mL; in step 3③, step 3② is repeated three to five times, and after sealing, the mixture is heated at 110℃~120℃ for 70h~72h. After the reaction is completed, the solid product is collected by centrifugation, washed 2 to 4 times each with N,N-dimethylformamide and methanol, and then extracted with N,N-dimethylformamide and methanol respectively. Finally, the product is vacuum dried at 80℃ for 10h~12h.
7. The method for preparing an all-organic ionic liquid confined nanocatalytic material according to claim 1, characterized in that... The mass-to-volume ratio of PTZpy, methyl bromide, and N,N-dimethylformamide in step four is (0.03g~0.08g):(0.02g~0.04g):90mL; the stirring time at room temperature in step four is 20h~24h; the washing in step four involves washing 3~5 times with anhydrous ethanol; the vacuum drying temperature in step four is 60℃~80℃, and the vacuum drying time is 10h~12h.
8. The method for preparing an all-organic ionic liquid confined nanocatalytic material according to claim 1, characterized in that... The alcohol solvent mentioned in step five is methanol, ethanol, propanol, isopropanol, or butanol; the mass ratio of PTZpy(+) to pyridine tricarboxylic acid salt ionic liquid mentioned in step five is 0.05 g:(2.5 mg~12.5 mg); the mass ratio of PTZpy(+) to alcohol solvent mentioned in step five is 0.05 g:(3 mL~6 mL); the stirring time mentioned in step five is 1 h~2 h; the vacuum drying temperature mentioned in step five is 60℃~80℃.
9. The application of the all-organic ionic liquid confined nanocatalytic material prepared by the preparation method according to any one of claims 1 to 8, characterized in that... Application of the all-organic ionic liquid confined nanocatalytic material in the photocatalytic reduction of carbon dioxide to methane under visible light irradiation and pure water system.
10. The application of the all-organic ionic liquid confined nanocatalytic material according to claim 9, characterized in that... The photocatalytic reduction of carbon dioxide to methane using the all-organic ionic liquid confined nanocatalytic material under visible light irradiation and in a pure water system is carried out according to the following steps: All-organic ionic liquid confined nanocatalytic material powder was dispersed in ultrapure water, and the mixed solution was placed in a quartz reactor. After sealing the system, it was magnetically stirred. CO2 gas was bubbled through to purge the air in the device and reach adsorption equilibrium. At the same time, the cooling water was turned on to ensure that the reaction temperature was maintained at 20°C, and then the reactor was sealed. A 300W xenon lamp was used to simulate the sunlight and irradiated the reactor from the top during the catalytic reaction. The wavelength of the incident light was controlled by a filter. At fixed intervals, the generated products were detected using a photocatalytic gas chromatography detection system. CO and CH4 could be detected in the FID2 channel, and H2 and O2 could be detected in the TCD channel.