A Ti3C2 / MoS2 / ZnIn2S4 composite photocatalyst and its preparation method
By preparing a Ti3C2/MoS2/ZnIn2S4 composite photocatalyst, the problems of small specific surface area and high photogenerated electron recombination rate of ZnIn2S4 photocatalyst were solved, and a highly efficient photocatalytic water splitting to produce hydrogen was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HUBEI UNIV
- Filing Date
- 2022-10-28
- Publication Date
- 2026-06-26
AI Technical Summary
Existing ZnIn2S4 photocatalysts suffer from problems such as small specific surface area, high recombination rate of photogenerated electrons and holes, and inability to fully absorb visible light, resulting in low efficiency in practical applications.
Accordion-shaped Ti3C2 nanomaterials were synthesized by etching, and MoS2 was grown on its surface. Finally, ZnIn2S4 was deposited on its surface to form a Ti3C2/MoS2/ZnIn2S4 composite photocatalyst. Through interfacial coupling, a metal sulfide s-type heterojunction was formed, which suppressed the recombination of photogenerated electrons and holes, improved the migration rate of photogenerated electrons, and utilized the photothermal properties of MoS2 to accelerate the activation of water molecules.
It improves the photocatalytic activity and stability of the photocatalyst, enhances its absorption capacity for visible light, promotes the separation of photogenerated electron and hole pairs, and improves the efficiency of photocatalytic water splitting to produce hydrogen.
Smart Images
Figure CN117983247B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a photocatalytic material, specifically to a method for preparing a Ti3C2 / MoS2 / ZnIn2S4 composite photocatalyst, belonging to the field of materials synthesis technology. Background Technology
[0002] With the continuous development and progress of human society, the emergence and popularization of transportation tools such as automobiles, ships, and airplanes, as well as the large-scale industrial manufacturing, the Earth's primary fossil fuels are being continuously consumed. Consequently, environmental pollution and water pollution problems are becoming increasingly severe. Furthermore, the reserves of primary fossil fuels such as oil and natural gas are finite, and the energy crisis has become a serious problem facing humanity. Hydrogen energy, as a clean energy source, can not only alleviate the energy crisis but also avoid environmental pollution. Therefore, developing green hydrogen production technology is an urgent task. Currently, more than 95% of hydrogen in my country is still produced from fossil fuels, resulting in gray and blue hydrogen. Only hydrogen produced by decomposing water using clean energy is green hydrogen. Currently, there are three typical technical routes for solar-powered water splitting to produce hydrogen: photovoltaic-assisted water electrolysis, photocatalytic water splitting, and photoelectrochemical water splitting. Using semiconductor powder photocatalysts to achieve solar-powered water splitting to produce hydrogen is the simplest and most economical of these three routes, with easier equipment construction, lower overall cost, and easier large-scale scaling. Photocatalytic technology has shown broad application prospects in areas such as utilizing solar energy to produce clean energy (hydrogen energy).
[0003] The basic principle of photocatalytic water splitting for hydrogen production is as follows: when light radiates onto a semiconductor, and the radiation energy is greater than or equal to the band gap width of the semiconductor, electrons in the semiconductor are excited and transition from the valence band to the conduction band, while holes remain in the valence band. This allows the electrons and holes to reduce water to hydrogen or oxidize it to oxygen. Khan et al. proposed that materials used for photocatalytic water splitting to produce hydrogen should meet the following requirements: high stability, no photocorrosion, low cost, meeting the thermodynamic requirements of water splitting, and absorbing most wavelengths of sunlight. Currently, the main reason restricting the industrial application of photocatalytic hydrogen production is its low efficiency. To improve this efficiency, the following aspects should be considered: photocatalyst nano-sizing, ion doping, semiconductor coupling, dye photosensitization, noble metal deposition, electron trapping agents, surface chelation, and derivatization. The basic principle of these methods is to accelerate the separation of photogenerated electron and hole pairs and promote the transfer of photogenerated electrons. Since electron conduction is a very rapid process, while the adsorption and catalytic cracking of water molecules require relatively high activation energy, if water molecules can be converted into water vapor first, the efficiency of photocatalytic water splitting to produce hydrogen will be greatly improved.
[0004] Zinc indium sulfide (ZnIn2S4), a fascinating visible-light-responsive photocatalyst, is considered a promising photocatalyst material, attracting widespread interdisciplinary interest. Its non-toxicity, suitable band gap, high physicochemical stability and durability, ease of synthesis, and attractive catalytic activity make it a promising new research hotspot. However, the small specific surface area, high recombination rate of photogenerated electrons and holes, and inability to fully absorb visible sunlight in the visible light band of ZnIn2S4 still present many challenges for its practical applications.
[0005] Molybdenum disulfide (MoS2) is a two-dimensional (2D) transition metal (TMD) with weak van der Waals bonds between two layers of hexagonal sulfur atoms. It is one of the best-performing photoelectric materials among known two-dimensional semiconductors. Similar to ZnIn2S4, it is also a layered nanostructure material, and single-layer or few-layer MoS2 nanosheets can be obtained through physical or hydrothermal exfoliation methods. The interfacial coupling of the 2D / 2D MoS2-ZnIn2S4 composite photocatalyst can form a metal sulfide s-type heterojunction, which can greatly suppress the recombination of photogenerated electron-hole pairs in ZnIn2S4. Its excellent conductivity and relatively lower conduction band (CB) position compared to ZnIn2S4 significantly increase the migration rate of photogenerated electrons to the MoS2 nanosheets, which is beneficial for efficient hydrogen generation. Furthermore, MoS2 has a wide absorption range from near-infrared to near-ultraviolet light, making it an excellent photothermal material that can enhance the photothermal performance of the composite photocatalyst. Most current research treats MoS2 as an excellent cocatalyst, neglecting its photothermal properties. If these properties could be utilized, by first heating the water to increase its activation energy, the photocatalytic activity would be significantly enhanced.
[0006] Titanium carbide (MXene), a novel two-dimensional layered material, exhibits graphene-like properties. Composed of transition metal carbides / carbonitrides, it is widely used in various fields such as batteries, battery sensors, photothermal conversion, and photocatalytic hydrogen production. MXenes can serve as substrates for the growth of MoS2 / ZnIn2S4 s-type heterojunctions. Their abundant surface functional groups can couple with photocatalyst materials to effectively suppress hole-hole recombination. Excellent conductivity enables rapid transport of photogenerated carriers in the composite photocatalyst material, thereby improving the separation efficiency of photogenerated electron and hole pairs. Sufficient active sites provide suitable reaction sites for photocatalytic hydrogen evolution, and matching appropriate Fermi levels facilitates the formation of Schottky junctions. These significant advantages make MXene a promising candidate for heterojunction photocatalysts. Furthermore, titanium carbide is also an excellent photothermal conversion material. As a synergistic co-catalyst, it can enhance the light absorption capacity of the entire reaction system and accelerate the efficiency of photocatalytic hydrogen evolution in the composite photothermal-photocatalyst system.
[0007] To date, there have been no reports on Ti3C2 / MoS2 / ZnIn2S4s composite photocatalysts. Summary of the Invention
[0008] Accordion-shaped Ti3C2 nanomaterials were synthesized by etching, and then MoS2 was grown on its surface and inside to prepare a composite photothermal assisted photocatalyst Ti3C2 / MoS2. Finally, ZnIn2S4 photocatalyst was deposited on its surface in an oil bath to prepare a Ti3C2 / MoS2 / ZnIn2S4 composite photocatalyst. The prepared photocatalyst has excellent photocatalytic hydrogen evolution performance.
[0009] This invention provides a method for preparing a Ti3C2 / MoS2 / ZnIn2S4 composite photocatalyst, characterized in that the method includes the following steps:
[0010] (1) Ti3AlC2 powder was slowly added to an acidic etching solution and stirred in an ice-water bath for 72 h. The resulting product was centrifuged at 10000 r / min to separate the suspension, and then repeatedly washed with deionized water and ethanol until the pH of the suspension was ≥6. The treated suspension was vacuum dried at 60°C for 2 h to obtain accordion-shaped Ti3C2, which was then thoroughly ground.
[0011] (2) The composite photothermal assisted photocatalyst material Ti3C2 / MoS2 was prepared by hydrothermal method, ultrasonic composite method or chemical vapor deposition.
[0012] (3) Preparation method of ternary composite Ti3C2 / MoS2 / ZnIn2S4s composite photocatalyst: The composite photothermal assisted photocatalyst material prepared in step (2) is fully mixed into a mixed solution of hydrochloric acid solution and glycerol at pH=2.5, and fully ultrasonically mixed evenly. Then, zinc source, indium source and sulfur source are added in sequence. Finally, Ti3C2 / MoS2 / ZnIn2S4 composite photocatalyst is prepared by oil bath reaction. Finally, the obtained product is thoroughly washed by centrifugation with deionized water and ethanol. The product is vacuum dried at 60℃ for 2 hours and fully ground.
[0013] In the above preparation method, in step (1), the acidic solution involved in etching can be an HF solution or an aqueous solution of LiF and HCl;
[0014] In the above preparation method, in step (1), if HF is selected, the concentration of the acid is 10-50 wt%;
[0015] In the above preparation method, in step (1), if an aqueous solution of LiF and HCl is selected, the concentration of HCl is 9-12 mol / L;
[0016] In the above preparation method, in step (1), the ice bath time is 24-72 h;
[0017] In the above preparation method, if the hydrothermal method is selected in step (2), the accordion-shaped Ti3C2 mixture from step (1) is fully dissolved in water by ultrasonication, and then a molybdenum source, a sulfur source, and citric acid are added to prepare the composite photothermal material Ti3C2 / MoS2 by a one-step hydrothermal method; the product is heated at 180-200 ℃ for 12-24 h in a hydrothermal oven, and the obtained product is thoroughly washed by centrifugation with deionized water and ethanol until pH≥6. The product is vacuum dried at 60℃ for 2 hours and then thoroughly ground; the molybdenum source can be ammonium molybdate, sodium molybdate, or potassium molybdate; the sulfur source can be thioacetamide, L-cysteine, or thiourea; the molybdenum source and sulfur source are added according to the stoichiometric ratio, and citric acid is used to adjust the pH of the solution to 5-6;
[0018] In the above preparation method, in step (2), if the ultrasonic composite method is selected, the MoS2 nanostructure is prepared first, the accordion-shaped Ti3C2 in step (1) and the prepared MoS2 nanostructure are mixed and ultrasonically dissolved in water for 12-24 hours, the obtained product is thoroughly washed by centrifugation with deionized water and ethanol, the product is vacuum dried at 60°C for 2 hours, and then thoroughly ground.
[0019] In the above preparation method, in step (2), if chemical vapor deposition is selected, the accordion-shaped Ti3C2 in step (1) is placed in a ceramic boat, and a ceramic boat of molybdenum oxide powder is placed upstream of the tube furnace. In a sulfur atmosphere, it is heated for 1-3 h at 700-1100℃. The sulfur atmosphere can be one or more of H2S, CS2 or S vapor.
[0020] In the above preparation method, in step (3), the zinc source can be one or more of zinc chloride, zinc nitrate, and zinc sulfate;
[0021] In the above preparation method, in step (3), the indium source can be one or more of indium chloride, indium nitrate, and indium sulfate;
[0022] In the above preparation method, in step (3), the sulfur source can be one or more of thioacetamide, L-cysteine, and thiourea;
[0023] In the above preparation method, in step (3), the ultrasonic time is 10-20 min;
[0024] In the above preparation method, in step (3), the oil bath reaction temperature is 60-80℃;
[0025] In the above preparation method, in step (3), the oil bath reaction time is 1-2 hours;
[0026] In the above preparation method, the drying temperature in step (3) is 50-60℃.
[0027] The Ti3C2 / MoS2 / ZnIn2S4 composite photocatalyst prepared using this technology has a relatively simple preparation process, can be synthesized on a large scale, has controllable cost, does not involve the use of precious metals, and the product has good photocatalytic activity and excellent long-term cycle stability. Attached Figure Description
[0028] Figure 1 The image shows the XRD pattern of the Ti3C2 / MoS2 / ZnIn2S4 composite photocatalyst prepared in Example 1 of this invention.
[0029] Figure 2 This is a FESEM image of the Ti3C2 / MoS2 / ZnIn2S4 composite photocatalyst prepared in Example 1 of this invention.
[0030] Figure 3 This is a graph showing the photocatalytic hydrogen evolution rate of the Ti3C2 / MoS2 / ZnIn2S4 composite photocatalyst prepared in Example 1 of this invention. Detailed Implementation
[0031] The technical solution of the present invention will be further described below with reference to the embodiments.
[0032] This invention proposes a method for preparing a high-performance Ti3C2 / MoS2 / ZnIn2S4 composite photocatalyst. The method is characterized by employing a hydrothermal method to densely grow nanosheet-like MoS2 on accordion-shaped Ti3C2, followed by oil bath deposition of the photocatalyst ZnIn2S4 on its surface to prepare the composite photocatalyst. The method includes the following steps and contents:
[0033] (1) The precursor Ti3AlC2 powder was slowly added to the etchant solution and stirred in an ice-water bath at room temperature for 72 h. The mixture was centrifuged at 10000 r / min, the supernatant was removed, and the suspension was washed repeatedly with deionized water and ethanol until the pH of the suspension was ≥6. The treated suspension was dried under vacuum at 60°C for 2 h to obtain accordion-shaped Ti3C2 (MXene) etchant, which can be obtained by using HF solution or an aqueous solution of LiF and HCl.
[0034] (2) The composite photothermal assisted photocatalyst material Ti3C2 / MoS2 was prepared by hydrothermal method, ultrasonic composite method or chemical vapor deposition.
[0035] (3) The photothermal-assisted photocatalyst material Ti3C2 / MoS2, hydrochloric acid solution with pH=2-3, and glycerol were thoroughly mixed in a round-bottom flask and sonicated for 20 minutes. Then, tungsten source, sulfur source, and zinc source were added and thoroughly mixed and sonicated for 5-10 minutes. The mixture was then transferred to an oil bath for reaction at 60-80℃ for 2-3 hours. After the reaction, the mixture was cooled to room temperature, centrifuged and filtered at 10000 r / min, and finally vacuum dried at 60℃ for 8-12 hours to obtain the Ti3C2 / MoS2 / ZnIn2S4 composite photocatalyst. The zinc source can be zinc chloride, zinc nitrate, zinc sulfate, etc.; the indium source can be indium chloride, indium nitrate, indium sulfate, etc.; and the sulfur source can be thioacetamide, L-cysteine, thiourea, etc.
[0036] In summary, this technology can be used to obtain high-performance Ti3C2 / MoS2 / ZnIn2S4 composite photocatalysts.
[0037] Specific Example 1: 1.0 g of Ti3AlC2 powder was slowly added to 30 mL of HF solution (40 wt%) and stirred in an ice-water bath at room temperature for 72 h. The mixture was centrifuged at 10000 r / min, the supernatant was removed, and the suspension was repeatedly washed with deionized water and ethanol until the pH of the suspension was ≥6. The treated suspension was dried under vacuum at 60°C for 2 h to obtain accordion-shaped Ti3C2 (MXene). Then, under normal conditions, 0.13 g of accordion-shaped Ti3C2 was completely dissolved in 40 mL of water by ultrasonic treatment for 10 minutes. Under continuous strong magnetic stirring, 0.35 g of (NH4)6Mo7O was added... 24 ·4H2O, 0.7g C2H5NS, and 0.09g citric acid were added to a 100mL flat-bottomed beaker and stirred for 30min. The mixture was then transferred to a polytetrafluoroethylene liner and hydrothermally reacted at 200℃ for 24h. The resulting product was washed approximately three times with deionized water and ethanol, and then vacuum dried at 60℃ until the powder was completely dry, yielding the photothermal-assisted photocatalyst material Ti3C2 / MoS2. Finally, 0.1g Ti3C2 / MoS2, 80ml hydrochloric acid solution (pH=2.5), and 20ml glycerol were thoroughly mixed in a 150ml round-bottom flask and sonicated for 20min. Then, 0.272g ZnCl2·2H2O, 0.586g InCl3·4H2O, and 0.3g thioacetamide were added sequentially. Finally, the mixture was reacted in an oil bath at 80℃ for 2 hours. The resulting products were washed three times with deionized water and dried in a vacuum at 60℃ to obtain the Ti3C2 / MoS2 / ZnIn2S4 composite photocatalyst.
[0038] Specific Example 2: 1.6 g of LiF powder was slowly added to 40 ml of 9 M HCl aqueous solution and stirred until homogeneous. Then, 1.0 g of Ti3AlC2 powder was slowly added to the mixed solution of LiF and HCl, and stirred at room temperature for 48 h. The product was centrifuged at 10000 r / min, the supernatant was removed, and then the product was repeatedly washed with deionized water and ethanol until the pH of the suspension was ≥6. The treated suspension was dried under vacuum at 60 °C for 2 h to obtain accordion-shaped Ti3C2. Then, ammonium molybdate (0.35 g) and thiourea (0.7 g) were added to 40 ml of deionized water, and the mixture was stirred vigorously for 1 h. The mixture was then transferred to a 50 ml high-pressure reactor, sealed, and reacted at 200 °C for 20 h. After cooling to room temperature, the product was washed several times with ethanol and deionized water by centrifugation (10000 rpm, 10 min). Then, MoS2 was obtained by vacuum drying at 60℃. 0.13g of accordion-shaped Ti3C2 and 0.05g of MoS2 nanostructures were mixed and dissolved in water by ultrasonication for 12-24h. The resulting product was washed thoroughly by centrifugation with deionized water and ethanol. The product was then vacuum dried at 60℃ for 2 hours and thoroughly ground to obtain the photothermal assisted photocatalyst material Ti3C2 / MoS2. Finally, 0.1g of Ti3C2 / MoS2, 80ml of hydrochloric acid solution with pH=2.5 and 20ml of glycerol were thoroughly mixed in a 150ml round-bottom flask and ultrasonicated for 20 minutes. Then, 0.272g ZnCl2·2H2O, 0.586g InCl3·4H2O, and 0.3g thioacetamide were added sequentially. Finally, the mixture was reacted in an oil bath at 80℃ for 2 hours. The resulting products were washed three times with deionized water and dried in a vacuum at 60℃ to obtain the Ti3C2 / MoS2 / ZnIn2S4 composite photocatalyst.
[0039] Specific Example 3: 1.0 g of Ti3AlC2 powder was slowly added to 30 mL of HF solution (40 wt%) and stirred in an ice-water bath at room temperature for 72 h. The mixture was centrifuged at 10000 r / min, the supernatant was removed, and the solution was repeatedly washed with deionized water and ethanol until the pH of the suspension was ≥6. The treated suspension was dried under vacuum at 60 °C for 2 h to obtain accordion-shaped Ti3C2 (MXene). Then, 0.13 g of the accordion-shaped Ti3C2 was placed in a ceramic boat, and a ceramic boat containing 0.5 g of molybdenum oxide powder was placed upstream of a tube furnace. The furnace was heated at 900 °C for 2 h in a sulfuric acid vapor atmosphere to obtain the photothermal-assisted photocatalyst material Ti3C2 / MoS2. Finally, 0.1 g of Ti3C2 / MoS2, 80 mL of hydrochloric acid solution at pH=2.5, and 20 mL of glycerol were thoroughly mixed in a 150 mL round-bottom flask and sonicated for 20 minutes. Then, 0.272g ZnCl2·2H2O, 0.586g InCl3·4H2O, and 0.3g thioacetamide were added sequentially. Finally, the mixture was reacted in an oil bath at 80℃ for 2 hours. The resulting products were washed three times with deionized water and dried in a vacuum at 60℃ to obtain the Ti3C2 / MoS2 / ZnIn2S4 composite photocatalyst.
[0040] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the patent application of the present invention are within the scope of the present invention.
Claims
1. A method for preparing a Ti3C2 / MoS2 / ZnIn2S4 composite photocatalyst, characterized in that, The method includes the following steps: (1) Preparation of accordion-shaped Ti3C2: Ti3AlC2 powder is slowly added to HF solution or aqueous solution of LiF and HCl, stirred in an ice water bath, and the resulting product is centrifuged to separate the suspension. Then, it is repeatedly centrifuged and washed with deionized water and ethanol until the pH of the suspension is ≥6. The treated suspension is vacuum dried to obtain accordion-shaped Ti3C2, which is then thoroughly ground. (2) The composite photothermal assisted photocatalyst material Ti3C2 / MoS2 was prepared by hydrothermal method, ultrasonic composite method or chemical vapor deposition; (3) Preparation method of ternary composite photocatalyst: The prepared Ti3C2 / MoS2 was thoroughly mixed into a mixed solution of hydrochloric acid and glycerol at pH=2.
5. Then, zinc source, indium source and sulfur source were added in sequence. Finally, Ti3C2 / MoS2 / ZnIn2S4 composite photocatalyst was prepared by oil bath reaction. The obtained product was thoroughly washed by centrifugation with deionized water and ethanol, vacuum dried, and thoroughly ground.
2. The preparation method according to claim 1, characterized in that, In step (1), if HF is selected, the acid concentration is 10-50 wt%; in step (1), if an aqueous solution of LiF and HCl is selected, the HCl concentration is 9-12 mol / L; in step (1), the ice bath time is 24-72 h; in step (2), if the hydrothermal method is selected, the accordion-shaped Ti3C2 mixture from step (1) is fully dissolved in water by ultrasonication, and then molybdenum source, sulfur source and citric acid are added to prepare the composite photothermal material Ti3C2 / MoS2 by one-step hydrothermal method; the mixture is heated in a hydrothermal box at 180-200℃ for 12-24 hours. h, the obtained product is thoroughly washed by centrifugation with deionized water and ethanol until pH≥6, the product is vacuum dried at 60℃ for 2 hours and thoroughly ground; the molybdenum source is ammonium molybdate, sodium molybdate or potassium molybdate, the sulfur source is thioacetamide, L-cysteine or thiourea; the molybdenum source and sulfur source are added according to stoichiometric ratio, and citric acid is used to adjust the pH of the solution to 5~6; in step (2), if the ultrasonic composite method is selected, the MoS2 nanostructure is prepared first, the accordion-shaped Ti3C2 in step (1) and the prepared MoS2 nanostructure are mixed and ultrasonically dissolved in water for 12-24h, the obtained product is thoroughly washed by centrifugation with deionized water and ethanol, the product is vacuum dried at 60℃ for 2 hours and thoroughly ground; in step (2), if the chemical vapor deposition method is selected, the accordion-shaped Ti3C2 in step (1) is placed in a ceramic boat, a ceramic boat of molybdenum oxide powder is placed upstream of the tube furnace, and heated for 1-3 hours in a sulfur atmosphere at 700-1100℃. h, wherein the sulfidation atmosphere is one or more of H2S, CS2 or S vapor; in step (3), the zinc source is one or more of zinc chloride, zinc nitrate or zinc sulfate; in step (3), the indium source is one or more of indium chloride, indium nitrate or indium sulfate; in step (3), the sulfur source is one or more of thioacetamide, L-cysteine or thiourea; in step (3), the oil bath reaction temperature is 60-80 ℃.