Preparation method and application of ionic liquid modified CuInS2 catalyst
By modifying CuInS2 catalyst with ionic liquid, the problems of low yield and poor selectivity in photothermal catalytic CO2 reduction were solved, achieving efficient low-temperature conversion of CO2 to ethylene and improving catalyst activity and energy utilization.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-14
- Publication Date
- 2026-04-14
AI Technical Summary
Existing photocatalysts exhibit low yields, poor selectivity, and low energy utilization in photothermal catalytic CO2 reduction, making it difficult to efficiently convert CO2 into high-value chemicals such as ethylene.
A method for preparing CuInS2 catalysts modified with ionic liquids was adopted. By controlling the structure of the ionic liquid, non-metallic N and F elements were doped and abundant sulfur vacancies were formed in CuInS2 catalysts, which improved the charge transfer ability and photogenerated electron-hole separation ability, and promoted the CC coupling reaction.
The system achieves efficient reduction of CO2 to C2H4 at low temperatures with a selectivity of up to 96.3%, reducing energy consumption and improving photothermal catalytic efficiency and energy utilization.
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Figure CN121847181A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of chemical catalysis and relates to a method for preparing an ionic liquid modified CuInS2 catalyst and its application. Background Technology
[0002] Solar-driven CO2 reduction to hydrocarbon fuels and other high-value chemicals has attracted widespread attention due to its high efficiency, energy saving, mild reaction, and sustainability. However, due to the high dissociation energy of the C=O double bond, the lack of surface active sites, and the slow reaction kinetics of CO2, most photo-driven CO2 reductions produce CO via a two-electron reduction pathway. Ethylene (C2H4) is one of the world's largest chemical products and a crucial raw material in the petrochemical industry. However, industrially, C2H4 is mainly obtained from naphtha through high-temperature steam cracking, which is energy-intensive and causes severe environmental pollution. Only a very few photocatalysts can achieve the conversion of CO2 to C2H4 under mild conditions, and these photocatalysts still suffer from low yields and poor selectivity for C2H4.
[0003] Photothermal catalysis effectively combines the low energy consumption of photocatalysis with the high catalytic efficiency of thermocatalysis. Currently, the most studied catalysts include metal oxides, metal sulfides, zeolites, porous organic polymers (POPs), metal-organic frameworks (MOFs), and covalent organic frameworks (COFs). Metal sulfides possess unique optical properties such as high specific surface area, narrow band gap, and rapid electron migration and charge generation rates, making them a promising photocatalytic material. Ionic liquids, due to the tunability of their anion and cation structures, allow for precise control of product size, morphology, and dispersion during inorganic material preparation, thus enabling the preparation of inorganic materials with varying properties. While photothermal catalysis is an effective way to mitigate global warming and address the energy crisis, it still faces challenges such as low yield, poor selectivity, and low light energy utilization. Therefore, developing photothermal catalysts with excellent photothermal conversion efficiency and high catalytic activity remains a pressing challenge in this field. Summary of the Invention
[0004] In view of the above-mentioned problems in the prior art, the purpose of this invention is to provide a method for preparing ionic liquid modified CuInS2 catalyst and its application in photothermal catalytic CO2 reduction to ethylene.
[0005] This invention provides a method for preparing an ionic liquid-modified CuInS2 catalyst, which includes the following steps:
[0006] A soluble copper salt, a soluble indium salt, thioacetamide, and solvent I are mixed to obtain a mixture. The mixture is placed in a sealed container and heated to 140–180°C. The solid product is washed and dried to obtain CuInS2 material. The molar ratio of the soluble copper salt to the soluble indium salt is 1:(0.1–5), the concentration of the copper salt is 8–15 mmol / L, and solvent I is water or a mixture of ethanol and water.
[0007] The CuInS2 material, ionic liquid, and solvent II are mixed, stirred, and dried after solvent evaporation to obtain a pretreated catalyst. The pretreated catalyst is then calcined at 300℃–500℃ for 1–5 hours under an inert gas or nitrogen atmosphere to obtain the ionic liquid-modified CuInS2 catalyst. The cationic structure of the ionic liquid is as follows: Where R1, R2, R3, R4, and R5 are the same or different values of C. n H 2n+1 , 1≤n≤12; the anion is BF4. - .
[0008] This invention also provides the application of the ionic liquid modified CuInS2 catalyst obtained by the above method in the photothermal catalytic reduction of carbon dioxide to produce ethylene.
[0009] Compared with existing technologies, the present invention has the following beneficial effects:
[0010] (1) This invention successfully constructed an ionic liquid-modified CuInS2 catalyst with good structure and chemical stability. Through ionic liquid regulation, a CuInS2 catalyst with non-metallic N and F element doping and abundant sulfur vacancies was formed. In the photothermal catalytic CO2 reaction, this structure effectively improved the charge transfer ability and the photogenerated electron-hole separation ability, which is beneficial to improving the catalytic activity. At the same time, the enhanced sulfur vacancies help the enrichment and transformation of CO intermediates during the reduction process, thereby promoting the CC coupling reaction and obtaining high-value-added C2H4 products with a selectivity of up to 96.3%.
[0011] (2) Photothermal catalysis has a lower reaction temperature than traditional thermocatalysis, reducing energy consumption and lowering reaction costs. This invention has found that ionic liquid modified CuInS2 catalyst, using water as a reducing agent, achieves photothermal catalytic reduction of CO2 to C2H4, and the efficiency of photothermal catalysis is an order of magnitude higher than that of photocatalysis and thermocatalysis.
[0012] (3) The photothermal catalyst construction and photothermal catalytic reduction method based on the present invention only requires water as a reducing agent to supply protons, achieving efficient reduction of CO2 to C2H4 at relatively low temperatures. This method features high yield and selectivity, and is environmentally friendly and sustainable. Compared with traditional visible light-driven photocatalysts, it has higher energy utilization and more significant economic benefits. Attached Figure Description
[0013] Figure 1 This is a scanning electron microscope image of the ionic liquid-modified CuInS2 catalyst obtained in Example 1 of the present invention;
[0014] Figure 2 This is a scanning electron microscope image of the CuInS2 catalyst obtained in Comparative Example 1 of the present invention.
[0015] Figure 3 XPS spectra of N1s of the ionic liquid modified CuInS2 catalysts obtained in Examples 4-6 of this invention and the CuInS2 catalyst obtained in Comparative Example 1.
[0016] Figure 4 XPS spectra of F1s of the ionic liquid modified CuInS2 catalysts obtained in Examples 4-6 of this invention and the CuInS2 catalyst obtained in Comparative Example 1.
[0017] Figure 5 The EPR spectra of the ionic liquid modified CuInS2 catalysts obtained in Examples 4-6 of this invention and the CuInS2 catalyst obtained in Comparative Example 1 are shown.
[0018] Figure 6 XRD phase diagrams of the ionic liquid-modified CuInS2 catalysts obtained in Examples 1-3 of this invention, and the CuInS2 catalyst obtained in Comparative Example 1.
[0019] Figure 7 XRD phase diagrams of the ionic liquid-modified CuInS2 catalysts obtained in Examples 4-6 of this invention, and the CuInS2 catalyst obtained in Comparative Example 1. Detailed Implementation
[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0021] This invention provides a method for preparing an ionic liquid-modified CuInS2 catalyst, which includes the following steps:
[0022] S01: A soluble copper salt, a soluble indium salt, thioacetamide, and solvent I are mixed to obtain a mixture. The mixture is placed in a sealed container and heated to 140–180°C. The solid product is washed and dried to obtain CuInS2 material. The molar ratio of the soluble copper salt to the soluble indium salt is 1:(0.1–5), the concentration of the copper salt is 8–15 mmol / L, and solvent I is water or a mixture of ethanol and water.
[0023] S02: The CuInS2 material, ionic liquid, and solvent II are mixed, stirred, and the solvent is evaporated and dried to obtain a pretreated catalyst. The pretreated catalyst is calcined at 300℃~500℃ for 1~5h under an inert gas or nitrogen atmosphere to obtain the ionic liquid-modified CuInS2 catalyst. The cationic structure of the ionic liquid is as follows: Where R1, R2, R3, R4, and R5 are the same or different values of C. n H 2n+1 , 1≤n≤12; the anion is BF4. - .
[0024] In step S01, the soluble copper salt can be copper nitrate, copper sulfate, copper chloride, and copper acetate, or it can be a soluble copper salt containing water of crystallization. The soluble indium salt is indium chloride. Copper-containing metal salts are not limited to those listed above; other commonly used copper-containing metal salts in the art can also be used in this invention. The molar ratio of the soluble copper salt to the soluble indium salt is 1:(0.5-2).
[0025] Specifically, the solid product is washed four times by alternating washing and centrifugation with ethanol and water at a speed of 7000–9000 rpm for 1–3 min. The centrifuged product is then vacuum-dried at 75°C for 10–18 h. Preferably, the solvent is a mixture of ethanol and water, with a volume ratio of ethanol to water of 1:(0.1–5).
[0026] In step S02, preferably, the cation structure of the ionic liquid is as follows: Where R1 represents the same or different C n H 2n+1 , 1≤n≤12; the anion is BF4. - More preferably, the ionic liquid is 1-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium tetrafluoroborate, and 1-butyl-3-methylimidazolium tetrafluoroborate. The calcination temperature is 300℃ to 500℃, for example, 300℃, 350℃, 400℃, 450℃, 500℃, etc. The calcination time is 1h to 5h, for example, 1h, 2h, 3h, 4h, 5h, etc. Solvent II is a low-boiling-point solvent capable of dissolving the ionic liquid, such as methanol, ethanol, etc.
[0027] By controlling the ionic liquid, a catalyst with non-metallic N and F doping and abundant sulfur vacancies was formed. In the photothermal catalytic CO2 reaction, this structure effectively enhances the charge transfer ability and the photogenerated electron-hole separation ability, which is beneficial to improving the catalytic activity. At the same time, the enhanced sulfur vacancies help to enrich and transform the CO intermediate state during the reduction process, thereby promoting the CC coupling reaction and obtaining high-value C2H4 products.
[0028] Furthermore, the present invention also provides the application of the ionic liquid modified CuInS2 catalyst obtained by the above method in the photothermal catalytic reduction of CO2 to produce ethylene.
[0029] The CO2 reduction is carried out in a fixed-bed reactor using a 300W xenon lamp of full wavelength as the light source. The reaction temperature is 120℃-140℃, the reaction time is 4-8 h, the reaction pressure is 0.1-2.0 MPa, and the gas flow rate is 1-10 mL / min. -1 In the process of catalytic photothermal CO2 reduction by ionic liquid modified CuInS2 catalyst, a sacrificial agent is added. The sacrificial agent is triethanolamine (TEOA), diethanolamine (DEA), ethanolamine (MEA), glycerol (C3H8O3), etc., preferably at least one of TEOA, DEA, and MEA.
[0030] The following specific examples illustrate the preparation method of ionic liquid-modified CuInS2 catalysts and their application in the photothermal catalytic reduction of CO2 to C2H4. The complexes in the following examples can be prepared directly using existing methods; of course, they can also be purchased directly from the market in other examples, and are not limited thereto.
[0031]
[0032]
[0033]
[0034] Example 1 :
[0035] Preparation of ionic liquid-modified CuInS2 catalyst:
[0036] Weigh 0.6134g CuCl2·2H2O, 1.0556g InCl3·4H2O and 0.541g C2H5NS into a 200mL container, add 80mL H2O and 80mL ethanol, and sonicate for 10min to obtain a mixture. Transfer the mixture to a 200mL high-pressure reactor lined with polytetrafluoroethylene, heat at 160℃ for 12h, centrifuge the obtained product, wash with ethanol and deionized water alternately, and vacuum dry at 75℃ for 12h to obtain CuInS2 material.
[0037] Weigh 0.1g of [Bmim]BF4 and 1g of CuInS2 material into a 50mL container, add 10mL of methanol, heat and stir at 75℃ until the methanol evaporates completely, dry under vacuum at 75℃ for 12h, and then place it in a tube furnace under an argon atmosphere and calcine it from room temperature to 350℃ at a heating rate of 5℃ / min for 2h to obtain the ionic liquid modified CuInS2 catalyst.
[0038] Photothermal catalytic carbon dioxide reduction:
[0039] 0.2 g of the ionic liquid-modified CuInS2 catalyst was weighed and added to 0.1 mL of triethanolamine. The catalyst was placed in a fixed bed for performance evaluation. The light source was a 300 W xenon lamp with full wavelength, the reaction temperature was 135 °C, the reaction pressure was 0.5 MPa, and the gas flow rate was 5 mL / min. -1 The reaction time was 6 hours. The product was detected online by gas chromatography, yielding an ethylene yield of 15.1 μmol·g⁻¹. -1 The selectivity rate was 96.2%.
[0040] Example 2 :
[0041] Preparation of ionic liquid-modified CuInS2 catalyst:
[0042] Weigh 0.6134g CuCl2·2H2O, 1.0556g InCl3·4H2O and 0.541g C2H5NS into a 200mL container, add 80mL H2O and 80mL ethanol, and sonicate for 10min to obtain a mixture. Transfer the mixture to a 200mL high-pressure reactor lined with polytetrafluoroethylene, heat at 160℃ for 12h, centrifuge the obtained product, wash with ethanol and deionized water alternately, and vacuum dry at 75℃ for 12h to obtain CuInS2 material.
[0043] Weigh 0.1g of [Bmim]BF4 and 1g of CuInS2 material into a 50mL container, add 10mL of methanol, heat and stir at 75℃ until the methanol evaporates completely, dry under vacuum at 75℃ for 12h, and then place it in a tube furnace under an argon atmosphere and calcine it from room temperature to 400℃ at a heating rate of 5℃ / min for 2h to obtain the ionic liquid modified CuInS2 catalyst.
[0044] Photothermal catalytic carbon dioxide reduction:
[0045] 0.2 g of the ionic liquid-modified CuInS2 catalyst was weighed and added to 0.1 mL of triethanolamine. The catalyst was placed in a fixed bed for performance evaluation. The light source was a 300 W xenon lamp with full wavelength, the reaction temperature was 135 °C, the reaction pressure was 0.5 MPa, and the gas flow rate was 5 mL / min. -1 The reaction time was 6 hours. The products were detected online by gas chromatography, yielding an ethylene yield of 13.8 μmol·g⁻¹. -1 The selectivity rate was 85.6%.
[0046] Example 3 :
[0047] Preparation of ionic liquid-modified CuInS2 catalyst:
[0048] Weigh 0.6134g CuCl2·2H2O, 1.0556g InCl3·4H2O and 0.541g C2H5NS into a 200mL container, add 80mL H2O and 80mL ethanol, and sonicate for 10min to obtain a mixture. Transfer the mixture to a 200mL high-pressure reactor lined with polytetrafluoroethylene, heat at 160℃ for 12h, centrifuge the obtained product, wash with ethanol and deionized water alternately, and vacuum dry at 75℃ for 12h to obtain CuInS2 material.
[0049] Weigh 0.1g of [Bmim]BF4 and 1g of CuInS2 material into a 50mL container, add 10mL of methanol, heat and stir at 75℃ until the methanol evaporates completely, dry under vacuum at 75℃ for 12h, and then place it in a tube furnace under an argon atmosphere and calcine it from room temperature to 450℃ at a heating rate of 5℃ / min for 2h to obtain the ionic liquid modified CuInS2 catalyst.
[0050] Photothermal catalytic carbon dioxide reduction:
[0051] 0.2 g of the ionic liquid-modified CuInS2 catalyst was weighed and added to 0.1 mL of triethanolamine. The catalyst was placed in a fixed bed for performance evaluation. The light source was a 300 W xenon lamp with full wavelength, the reaction temperature was 135 °C, the reaction pressure was 0.5 MPa, and the gas flow rate was 5 mL / min. -1 The reaction time was 6 hours. The products were detected online by gas chromatography, yielding an ethylene yield of 14.9 μmol·g⁻¹. -1 The selectivity rate was 84.7%.
[0052] Example 4 :
[0053] Preparation of ionic liquid-modified CuInS2 catalyst:
[0054] Weigh 0.6134g CuCl2·2H2O, 1.0556g InCl3·4H2O and 0.541g C2H5NS into a 200mL container, add 80mL H2O and 80mL ethanol, and sonicate for 10min to obtain a mixture. Transfer the mixture to a 200mL high-pressure reactor lined with polytetrafluoroethylene, heat at 160℃ for 12h, centrifuge the obtained product, wash with ethanol and deionized water alternately, and vacuum dry at 75℃ for 12h to obtain CuInS2 material.
[0055] Weigh 0.1g of [Mim]BF4 and 1g of CuInS2 material into a 50mL container, add 10mL of methanol, heat and stir at 75℃ until the methanol evaporates completely, dry under vacuum at 75℃ for 12h, and then place it in a tube furnace under an argon atmosphere and calcine it from room temperature to 350℃ at a heating rate of 5℃ / min for 2h to obtain the ionic liquid modified CuInS2 catalyst.
[0056] Photothermal catalytic carbon dioxide reduction:
[0057] 0.2 g of the ionic liquid-modified CuInS2 catalyst was weighed and added to 0.1 mL of triethanolamine. The catalyst was placed in a fixed bed for performance evaluation. The light source was a 300 W xenon lamp with full wavelength, the reaction temperature was 135 °C, the reaction pressure was 0.3 MPa, and the gas flow rate was 5 mL / min. -1 The reaction time was 6 hours. The products were detected online by gas chromatography, yielding an ethylene yield of 62.9 μmol·g⁻¹. -1 The selectivity rate was 94.7%.
[0058] Example 5 :
[0059] Preparation of ionic liquid-modified CuInS2 catalyst:
[0060] Weigh 0.6134g CuCl2·2H2O, 1.0556g InCl3·4H2O and 0.541g C2H5NS into a 200mL container, add 80mL H2O and 80mL ethanol, and sonicate for 10min to obtain a mixture. Transfer the mixture to a 200mL high-pressure reactor lined with polytetrafluoroethylene, heat at 160℃ for 12h, centrifuge the obtained product, wash with ethanol and deionized water alternately, and vacuum dry at 75℃ for 12h to obtain CuInS2 material.
[0061] Weigh 0.1g of [Emim]BF4 and 1g of CuInS2 material into a 50mL container, add 10mL of methanol, heat and stir at 75℃ until the methanol evaporates completely, dry under vacuum at 75℃ for 12h, and then place it in a tube furnace under an argon atmosphere and calcine it from room temperature to 350℃ at a heating rate of 5℃ / min for 2h to obtain the ionic liquid modified CuInS2 catalyst.
[0062] Photothermal catalytic carbon dioxide reduction:
[0063] 0.2 g of the ionic liquid-modified CuInS2 catalyst was weighed and added to 0.1 mL of triethanolamine. The catalyst was placed in a fixed bed for performance evaluation. The light source was a 300 W xenon lamp with full wavelength, the reaction temperature was 135 °C, the reaction pressure was 0.3 MPa, and the gas flow rate was 5 mL / min. -1The reaction time was 6 hours. The products were detected online by gas chromatography, yielding an ethylene yield of 81.7 μmol·g⁻¹. -1 The selectivity rate was 94.3%.
[0064] Example 6 :
[0065] Preparation of ionic liquid-modified CuInS2 catalyst:
[0066] Weigh 0.6134g CuCl2·2H2O, 1.0556g InCl3·4H2O and 0.541g C2H5NS into a 200mL container, add 80mL H2O and 80mL ethanol, and sonicate for 10min to obtain a mixture. Transfer the mixture to a 200mL high-pressure reactor lined with polytetrafluoroethylene, heat at 160℃ for 12h, centrifuge the obtained product, wash with ethanol and deionized water alternately, and vacuum dry at 75℃ for 12h to obtain CuInS2 material.
[0067] Weigh 0.1g of [Bmim]BF4 and 1g of CuInS2 material into a 50mL container, add 10mL of methanol, heat and stir at 75℃ until the methanol evaporates completely, dry under vacuum at 75℃ for 12h, and then place it in a tube furnace under an argon atmosphere and calcine it from room temperature to 350℃ at a heating rate of 5℃ / min for 2h to obtain the ionic liquid modified CuInS2 catalyst.
[0068] Photothermal catalytic carbon dioxide reduction:
[0069] 0.2 g of the ionic liquid-modified CuInS2 catalyst was weighed and added to 0.1 mL of triethanolamine. The catalyst was placed in a fixed bed for performance evaluation. The light source was a 300 W xenon lamp with full wavelength, the reaction temperature was 135 °C, the reaction pressure was 0.3 MPa, and the gas flow rate was 5 mL / min. -1 The reaction time was 6 hours. The product was detected online by gas chromatography, yielding an ethylene yield of 62.3 μmol·g⁻¹. -1 The selectivity rate was 95.0%.
[0070] Example 7 :
[0071] Preparation of ionic liquid-modified CuInS2 catalyst:
[0072] Weigh 0.6134g CuCl2·2H2O, 1.0556g InCl3·4H2O and 0.541g C2H5NS into a 200mL container, add 80mL H2O and 80mL ethanol, and sonicate for 10min to obtain a mixture. Transfer the mixture to a 200mL high-pressure reactor lined with polytetrafluoroethylene, heat at 160℃ for 12h, centrifuge the obtained product, wash with ethanol and deionized water alternately, and vacuum dry at 75℃ for 12h to obtain CuInS2 material.
[0073] Weigh out 0.1g of tetramethylammonium tetrafluoroborate (C4H) 12 BF4N and 1g of CuInS2 material were placed in a 50mL container, 10mL of methanol was added, and the mixture was heated and stirred at 75℃ until the methanol was completely evaporated. The mixture was then dried under vacuum at 75℃ for 12h. The mixture was then placed in a tube furnace under an argon atmosphere and calcined at 350℃ for 2h from room temperature at a heating rate of 5℃ / min to obtain the ionic liquid modified CuInS2 catalyst.
[0074] Photothermal catalytic carbon dioxide reduction:
[0075] 0.2 g of the ionic liquid-modified CuInS2 catalyst was weighed and added to 0.1 mL of triethanolamine. The catalyst was placed in a fixed bed for performance evaluation. The light source was a 300 W xenon lamp with full wavelength, the reaction temperature was 135 °C, the reaction pressure was 0.3 MPa, and the gas flow rate was 5 mL / min. -1 The reaction time was 6 hours. The products were detected online by gas chromatography, yielding an ethylene yield of 59.8 μmol·g⁻¹. -1 The selectivity rate was 90.2%.
[0076] Comparative Example 1 :
[0077] Preparation of CuInS2 catalyst:
[0078] Weigh 0.6134g CuCl2·2H2O, 1.0556g InCl3·4H2O and 0.541g C2H5NS into a 200mL container, add 80mL H2O and 80mL ethanol, and sonicate for 10min to obtain a mixture. Transfer the mixture to a 200mL high-pressure reactor lined with polytetrafluoroethylene, heat at 160℃ for 12h, centrifuge the obtained product, wash with ethanol and deionized water alternately, and vacuum dry at 75℃ for 12h to obtain CuInS2 catalyst.
[0079] Photothermal catalytic carbon dioxide reduction:
[0080] Weigh 0.2 g of the CuInS2 catalyst, add 0.1 mL of triethanolamine, and place in a fixed bed for catalyst performance evaluation. The light source is a 300 W xenon lamp with full wavelength, the reaction temperature is 135 °C, the reaction pressure is 0.5 MPa, and the gas flow rate is 5 mL / min. -1 The reaction time was 6 hours. The product was detected online by gas chromatography, yielding an ethylene yield of 3.0 μmol·g⁻¹. -1 The selectivity rate was 78.7%.
[0081] Comparative Example 2
[0082] Preparation of ionic liquid-modified CuInS2 catalyst:
[0083] Weigh 0.6134g CuCl2·2H2O, 1.0556g InCl3·4H2O and 0.541g C2H5NS into a 200mL container, add 80mL H2O and 80mL ethanol, and sonicate for 10min to obtain a mixture. Transfer the mixture to a 200mL high-pressure reactor lined with polytetrafluoroethylene, heat at 160℃ for 12h, centrifuge the obtained product, wash with ethanol and deionized water alternately, and vacuum dry at 75℃ for 12h to obtain CuInS2 material.
[0084] Weigh out 0.1 g of 1-butyl-3-methylimidazolium thiocyanate (C9H). 15 N3S) and 1g CuInS2 material were placed in a 50mL container, 10mL of methanol was added, and the mixture was heated and stirred at 75℃ until the methanol was completely evaporated. The mixture was then dried under vacuum at 75℃ for 12h. The mixture was then placed in a tube furnace under an argon atmosphere and calcined at 350℃ for 2h from room temperature at a heating rate of 5℃ / min to obtain the ionic liquid modified CuInS2 catalyst.
[0085] Photothermal catalytic carbon dioxide reduction:
[0086] 0.2 g of the ionic liquid-modified CuInS2 catalyst was weighed and added to 0.1 mL of triethanolamine. The catalyst was placed in a fixed bed for performance evaluation. The light source was a 300 W xenon lamp with full wavelength, the reaction temperature was 135 °C, the reaction pressure was 0.5 MPa, and the gas flow rate was 5 mL / min. -1 The reaction time was 6 hours. The product was detected online by gas chromatography, yielding an ethylene yield of 9.9 μmol·g⁻¹. -1 The selectivity rate was 58.0%.
[0087] Comparative Example 3
[0088] Preparation of ionic liquid-modified CuInS2 catalyst:
[0089] Weigh 0.6134g CuCl2·2H2O, 1.0556g InCl3·4H2O and 0.541g C2H5NS into a 200mL container, add 80mL H2O and 80mL ethanol, and sonicate for 10min to obtain a mixture. Transfer the mixture to a 200mL high-pressure reactor lined with polytetrafluoroethylene, heat at 160℃ for 12h, centrifuge the obtained product, wash with ethanol and deionized water alternately, and vacuum dry at 75℃ for 12h to obtain CuInS2 material.
[0090] Weigh 0.1 g of 1-hydroxyethyl-3-methylimidazolium chloride (C6H) 11 ON2Cl and 1g CuInS2 material were placed in a 50mL container, 10mL of methanol was added, and the mixture was heated and stirred at 75℃ until the methanol was completely evaporated. The mixture was then dried under vacuum at 75℃ for 12h. The mixture was then placed in a tube furnace under an argon atmosphere and calcined at 350℃ for 2h from room temperature at a heating rate of 5℃ / min to obtain the ionic liquid modified CuInS2 catalyst.
[0091] Photothermal catalytic carbon dioxide reduction:
[0092] 0.2 g of the ionic liquid-modified CuInS2 catalyst was weighed and added to 0.1 mL of triethanolamine. The catalyst was placed in a fixed bed for performance evaluation. The light source was a 300 W xenon lamp with full wavelength, the reaction temperature was 135 °C, the reaction pressure was 0.5 MPa, and the gas flow rate was 5 mL / min. -1 The reaction time was 6 hours. The products were detected online by gas chromatography, yielding an ethylene yield of 5.7 μmol·g⁻¹. -1 The selectivity rate was 42.6%.
[0093] Comparative Example 4
[0094] Preparation of CuInS2 catalyst:
[0095] Weigh 0.6134g CuCl2·2H2O, 1.0556g InCl3·4H2O and 0.541g C2H5NS into a 200mL container, add 80mL H2O and 80mL ethanol, and sonicate for 10min to obtain a mixture. Transfer the mixture to a 200mL high-pressure reactor lined with polytetrafluoroethylene, heat at 160℃ for 12h, centrifuge the obtained product, wash with ethanol and deionized water alternately, and vacuum dry at 75℃ for 12h to obtain CuInS2 material.
[0096] The CuInS2 material was placed in a tube furnace under an argon atmosphere and calcined at 350°C for 2 hours from room temperature at a heating rate of 5°C / min to obtain the CuInS2 catalyst.
[0097] Photothermal catalytic carbon dioxide reduction:
[0098] Weigh 0.2 g of the CuInS2 catalyst, add 0.1 mL of triethanolamine, and place in a fixed bed for catalyst performance evaluation. The light source is a 300 W xenon lamp with full wavelength, the reaction temperature is 135 °C, the reaction pressure is 0.5 MPa, and the gas flow rate is 5 mL / min. -1 The reaction time was 6 hours. The product was detected online by gas chromatography, yielding an ethylene yield of 0.8 μmol·g⁻¹. -1 The selectivity rate was 61.5%.
[0099] Depend on Figures 1-2 It can be seen that the hydrothermally synthesized CuInS2 catalyst has a regular flower-like microsphere morphology composed of nanosheets. The catalyst surface after ionic liquid modification is rougher, which is more conducive to CO2 adsorption and proton transfer processes; Figures 3-4 It can be seen that the catalyst modified by the ionic liquid incorporates N and F elements; Figure 5 It can be seen that the catalyst modified by the ionic liquid generates a large number of sulfur vacancies. These surface sulfur vacancies can capture photogenerated electrons, thereby inhibiting electron-hole recombination, and can also increase the adsorption and activation of carbon dioxide, thus improving the photothermal reduction efficiency of CO2. Figures 5-6 It can be seen that the ionic liquid-modified CuInS2 catalysts obtained by calcination at 350℃, 400℃, and 450℃ in an inert atmosphere, as well as a series of ionic liquid-modified CuInS2 catalysts, showed increased crystallinity compared to the CuInS2 catalyst formed in Comparative Example 1. The experimental results show that the ionic liquid-modified CuInS2 catalyst has N and F element doping and abundant sulfur vacancy structure, which improves its adsorption and activation ability for carbon dioxide and is conducive to the enrichment of intermediate CO* and further CC coupling reaction, thereby enhancing the ethylene selectivity.
[0100] The applicant declares that the detailed method of the present invention is illustrated by the above embodiments, but the present invention is not limited to the above detailed method, that is, it does not mean that the present invention must rely on the above detailed method to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.
Claims
1. A method for preparing an ionic liquid-modified CuInS2 catalyst, characterized in that, Includes the following steps: A soluble copper salt, a soluble indium salt, thioacetamide, and solvent I are mixed to obtain a mixture. The mixture is placed in a sealed container and heated to 140–180°C. The solid product is washed and dried to obtain CuInS2 material. The molar ratio of the soluble copper salt to the soluble indium salt is 1:(0.1–5), the concentration of the copper salt is 8–15 mmol / L, and solvent I is water or a mixture of ethanol and water. The CuInS2 material, ionic liquid, and solvent II are mixed, stirred, and dried after solvent evaporation to obtain a pretreated catalyst. The pretreated catalyst is then calcined at 300℃–500℃ for 1–5 hours under an inert gas or nitrogen atmosphere to obtain the ionic liquid-modified CuInS2 catalyst. The cationic structure of the ionic liquid is as follows: Where R1, R2, R3, R4, and R5 are the same or different values of C. n H 2n+1 , 1≤n≤12; the anion is BF4. - .
2. The preparation method according to claim 1, characterized in that, The soluble copper salt is at least one of copper nitrate, copper sulfate, copper chloride, and copper acetate.
3. The preparation method according to claim 1, characterized in that, The soluble indium salt is indium chloride.
4. The preparation method according to claim 1, characterized in that, The molar ratio of the soluble copper salt to the soluble indium salt is 1:(0.5-2).
5. The preparation method according to claim 1, characterized in that, The cationic structure of the ionic liquid is as follows: Where R1 represents the same or different C n H 2n+1 , 1≤n≤12; the anion is BF4. - .
6. The preparation method according to any one of claims 1 or 5, characterized in that, The ionic liquid is any one of 1-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium tetrafluoroborate, and 1-butyl-3-methylimidazolium tetrafluoroborate.
7. The preparation method according to claim 1, characterized in that, Solvent II is methanol and / or ethanol.
8. The application of an ionic liquid modified CuInS2 catalyst obtained by the preparation method as described in claims 1 to 7 in the photothermal catalytic reduction of CO2 to produce ethylene.
9. The ionic liquid-modified CuInS2 catalyst according to claim 8, characterized in that, The reaction temperature was 120℃-140℃, the reaction time was 4-8 h, the reaction pressure was 0.1~2.0 MPa, and the gas flow rate was 1-10 mL·min. -1 .
10. The ionic liquid-modified CuInS2 catalyst according to claim 8, characterized in that, The ionic liquid modified CuInS2 catalyst is used to add a sacrificial agent to the photothermal CO2 reduction process. The sacrificial agent is at least one of triethanolamine, diethanolamine, ethanolamine and glycerol.