A layered bimetallic sulfide nanomaterial and its preparation method and application
By preparing layered bimetallic sulfide nanomaterials Cu2MoS4 nanosheets, the problem of low CO2 reduction activity in the existing technology was solved, and efficient photocatalytic CO2 reduction under visible light was achieved. The products included C1 and C2 products, showing excellent catalytic performance and stability.
Patent Information
- Application Number
- CN202310850759.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-07-11
- Publication Date
- 2025-09-26
- Estimated Expiration
- 2043-07-11
AI Technical Summary
In the existing semiconductor photocatalytic CO2 reduction reaction, the photocatalytic activity of carbon dioxide reduction is low. It is necessary to design photocatalysts with strong light absorption ability, fast carrier separation efficiency and rich active sites to improve the CO2 reduction performance.
Layered bimetallic sulfide nanomaterial Cu2MoS4 nanosheets are prepared by a solvothermal method and have a two-dimensional structure with a thickness of 20-30nm, a lateral size of 1-2μm, and a longitudinal size of 1-2μm. The photocatalytic activity is improved by utilizing its large specific surface area and bimetallic sites.
Efficient photocatalytic CO2 reduction was achieved under visible light conditions, and the products included not only the C1 product CO, but also the C2 product C2H4, showing excellent photocatalytic performance and repeatability, and increasing the production of CO and C2H4.
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of nanomaterials, and in particular to a layered bimetallic sulfide nanomaterial, a preparation method thereof, and an application thereof. Background Art
[0002] Semiconductor photocatalytic CO2 reduction is a promising chemical process for addressing resource, energy, and environmental challenges. In this process, carbon dioxide is reduced to hydrocarbons via a heterogeneous photocatalyst using water as an electron donor under the influence of sunlight. The semiconductor photocatalytic CO2 reduction reaction primarily consists of three steps: light absorption, separation and migration of photogenerated charge carriers, and surface redox reactions. Although some progress has been made in this field, the photocatalytic activity for CO2 reduction remains low. Therefore, it is necessary to design photocatalysts with strong light absorption, rapid charge carrier separation efficiency, and abundant active sites to improve CO2 reduction performance. Summary of the Invention
[0003] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide a layered bimetallic sulfide nanomaterial and its preparation method and application.
[0004] The present invention solves the technical problem by adopting the following technical solutions.
[0005] The present invention provides a layered bimetallic sulfide nanomaterial, which is a two-dimensional layered Cu2MoS4 nanosheet. The nanosheet has a thickness of 20-30nm, a lateral size of 1-2μm, and a longitudinal size of 1-2μm.
[0006] The present invention also provides a method for preparing the above-mentioned layered bimetallic sulfide nanomaterial, which comprises: sealing and heating a mixture of cuprous oxide nanocrystals, a molybdenum source, a sulfur source and ethylene glycol to react to obtain two-dimensional layered Cu2MoS4 nanosheets.
[0007] The present invention also provides an application of the layered bimetallic sulfide nanomaterial in photocatalytic reduction of CO2.
[0008] The present invention has the following beneficial effects:
[0009] The present invention provides a layered bimetallic sulfide nanomaterial, its preparation method, and application. The layered bimetallic sulfide nanomaterial is a two-dimensional layered Cu2MoS4 nanosheet. The two-dimensional layered Cu2MoS4 nanosheet has advantages such as uniform morphology, large specific surface area, multiple active sites, and strong light absorption and conversion capacity. When used in the photocatalytic reduction of CO2 under visible light conditions, the reduction products include not only the C1 product CO but also the C2 product C2H4. The layered bimetallic sulfide nanomaterial provided by the embodiments of the present invention not only exhibits excellent photocatalytic performance and repeatability, but also has high photocatalytic activity for the reduction of CO2 to C2H4 and CO, laying the foundation for the better application of two-dimensional transition metal sulfide nanomaterials in the field of photocatalysis. BRIEF DESCRIPTION OF THE DRAWINGS
[0010] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.
[0011] Figure 1 TEM image of the layered bimetallic sulfide nanomaterial provided in Example 1;
[0012] Figure 2 This is a graph showing the yield of CO2 reduction under visible light conditions for the layered bimetallic sulfide nanomaterial provided in Example 1 and the material obtained in the comparative example;
[0013] Figure 3 This is the UV-visible spectrum of the layered bimetallic sulfide nanomaterial provided in Example 1;
[0014] Figure 4 This is the time-resolved transient photoluminescence (TS-PL) fluorescence spectrum of the layered bimetallic sulfide nanomaterial provided in Example 1. DETAILED DESCRIPTION
[0015] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.
[0016] The following is a detailed description of a layered bimetallic sulfide nanomaterial, a preparation method, and applications thereof provided in an embodiment of the present invention.
[0017] In a first aspect, an embodiment of the present invention provides a layered bimetallic sulfide nanomaterial, which is a two-dimensional layered Cu2MoS4 nanosheet. The thickness of the nanosheet is 20-30 nm, the lateral size is 1-2 μm, and the longitudinal size is 1-2 μm.
[0018] In an optional embodiment, the layered bimetallic sulfide nanomaterial has a spectral absorption band edge of 710 nm and an optical band gap of 1.75 eV.
[0019] In an alternative embodiment, the time-resolved transient photoluminescence (TS-PL) fluorescence lifetime of the layered bimetallic sulfide nanomaterial is 51.48 ns.
[0020] Two-dimensional layered nanomaterials are considered to be the most promising photocatalytic materials. Their advantages include: (1) adjusting the energy band position through quantum size effect; (2) shortening the carrier diffusion path generated by the ultra-thin nature, greatly improving the transmission and separation efficiency of photogenerated carriers; (3) greatly increasing the specific surface area, and most anion vacancies or metal cation vacancies and active sites can be exposed on the surface to participate in the photocatalytic reaction; (4) defects on the two-dimensional nanostructure can narrow the band gap of the photocatalyst and expand the absorption range of the photocatalyst. Therefore, two-dimensional photocatalysts usually have excellent photocatalytic activity. Among the many two-dimensional catalysts, two-dimensional transition metal sulfides (TMDCs) with layered structures are currently the hot spot of two-dimensional material research, among which MoS2 is the most typical. The surface structure, electronic state and mechanical properties of TMDCs are generally easier to adjust than other two-dimensional materials to target different reactions and reduce unnecessary side reactions. The active sites of metal sulfides are generally divided into metal edge sites and S edge sites. In most metal sulfide semiconductors, due to unsaturated S atoms and interface S atoms, S edge sites usually behave as interface photocatalytic active sites. Although metal sulfides have many advantages mentioned above, their application in photocatalysis is also limited by problems such as rapid recombination of photogenerated electron-hole pairs, low mobility of photogenerated charges, and photocorrosion.
[0021] After long-term practice, the inventors have proposed a layered bimetallic sulfide nanomaterial. The layered bimetallic sulfide nanomaterial is a two-dimensional layered Cu2MoS4 nanosheet with bimetallic sites of Cu and Mo. The bimetallic on the nanosheet exhibits photocatalytic CO2 reduction activity. This is because the two-dimensional layered material has a large specific surface area, and most of the anion vacancies or metal cation vacancies and active sites can be exposed on the surface, which is conducive to their participation in the photocatalytic reaction. At the same time, the layered bimetallic sulfide nanomaterial provided by the embodiment of the present invention also has a narrow band gap and an adjustable absorption band edge, which makes it have greater absorption and conversion characteristics in the visible light range. It has a wide applicability as a photocatalytic material. Multiple experiments have also proved that the layered bimetallic catalyst provided by the embodiment of the present invention easily produces C1 products and C2 products in the photocatalytic CO2 reduction system, so that the layered bimetallic sulfide nanomaterial provided by the embodiment of the present invention exhibits excellent photocatalytic performance and repeatability in the photocatalytic CO2 reduction process, and has high activity in photocatalytic CO2 reduction to C2H4 and CO.
[0022] In a second aspect, an embodiment of the present invention provides a method for preparing the above-mentioned layered bimetallic sulfide nanomaterial, which comprises: sealing and heating a mixture of cuprous oxide nanocrystals, a molybdenum source, a sulfur source and ethylene glycol to react to obtain two-dimensional layered Cu2MoS4 nanosheets.
[0023] This embodiment of the present invention provides a method for preparing the aforementioned layered bimetallic sulfide nanomaterial. Using cuprous oxide nanocrystals, a molybdenum source, a sulfur source, and ethylene glycol as raw materials, a solvothermal method is used to successfully produce Cu2MoS4 nanosheets with excellent crystallization, high purity, and uniform morphology. This nanomaterial exhibits a large specific surface area, numerous active sites, and strong light absorption, facilitating photocatalytic reduction of CO2 and improving reaction efficiency.
[0024] In an optional embodiment, the sealed heating reaction temperature is 100-210°C and the reaction time is 2-24 hours. Experimental results show that different reaction times will synthesize nanomaterials with different morphologies, and too short a reaction time will form nanoparticles.
[0025] In an optional embodiment, the method further comprises: after the reaction is carried out by sealing and heating, collecting the solid powder by solid-liquid separation, washing the solid powder with deionized water and ethanol several times, and then drying to obtain the two-dimensional layered Cu2MoS4 nanosheets;
[0026] More preferably, the drying temperature is 40-100° C. and the drying time is 6-12 h.
[0027] In an alternative embodiment, the molar ratio of cuprous oxide nanocrystals, molybdenum source, sulfur source and ethylene glycol is (1-2):(1-3):(4-6):(1-2).
[0028] In an optional embodiment, the molybdenum source is selected from sodium molybdate; and the sulfur source is selected from thioacetamide.
[0029] In an optional embodiment, the cuprous oxide nanocrystals are obtained by the following method: dissolving a copper salt and a surfactant in water, adjusting the pH value of the solution to a strong alkaline state, and then adding a reducing agent to react to obtain cuprous oxide nanocrystals;
[0030] Preferably, the copper salt is selected from one or more of copper chloride, copper nitrate and copper sulfate; the surfactant is selected from polyvinylpyrrolidone; the reducing agent is selected from one or more of ascorbic acid, hydrazine and hydroxylamine hydrochloride; the mass ratio of the copper salt to the surfactant is 1:(10-20); and the molar ratio of the copper salt to the reducing agent is 1:(1-6).
[0031] In a third aspect, an embodiment of the present invention provides an application of the above-mentioned layered bimetallic sulfide nanomaterial in the photocatalytic reduction of CO2.
[0032] In an optional embodiment, during the photocatalytic reduction of CO2, a continuous flow system reactor is used to carry out the reduction experiment, a 300W xenon lamp is used as the light source, and the product components are analyzed by a mass spectrometer and a gas chromatograph;
[0033] Preferably, the reaction conditions for the photocatalytic reduction of CO2 are as follows: 5 mg of copper molybdenum sulfide photocatalyst is ultrasonically dispersed in 400 μl of deionized water, and the suspension is then dispersed on a glass fiber membrane. The glass fiber membrane is suspended in a 200 ml quartz glass reactor. The instrument is initially vacuum-treated, then evacuated with 0.1 MPa high-purity carbon dioxide gas, and the purge is repeated three times, and the reaction temperature is maintained at around 20°C. A 300W short-arc Xe lamp equipped with a visible light filter is used as a visible light source. The photocatalytic CO2 reduction product CO is measured using a gas chromatograph (GC, 2014A, Ar carrier, Shimadu). Other hydrocarbons are converted into CH4 through a methanation reactor and then analyzed using a flame ionization detector (FID).
[0034] In an optional embodiment, under irradiation conditions after λ is in the range of 420nm, when the two-dimensional layered Cu2MoS4 nanosheets perform photocatalytic reduction of CO2, the production of C2H4 is 6.78μmol / h / g, and the production of CO is 10.83μmol / h / g. The experimental results show that the layered copper sulfide molybdenum nanosheet material provided in the embodiment of the present invention, under visible light conditions, produces not only the C1 product CO but also the C2 product C2H4 in the photocatalytic reduction of CO2. The CO production of this nanomaterial is higher than that of the material obtained in the comparative example, and the materials obtained in the comparative example do not contain C2H4, indicating that the two-dimensional layered Cu2MoS4 nanosheets provided in the embodiment of the present invention have excellent catalytic properties. It is expected to be more widely used in photocatalytic CO2 reduction.
[0035] As can be seen from the above, the present invention provides a layered bimetallic sulfide nanomaterial and its preparation method and application. The layered bimetallic sulfide nanomaterial is a two-dimensional layered Cu2MoS4 nanosheet, which is synthesized by a simple solvent thermal method. The preparation process is cheap and the reaction conditions are mild. The prepared two-dimensional layered Cu2MoS4 nanosheet has good physical and chemical properties, especially a large specific surface area, the advantages of molybdenum and copper bimetallicity and strong light absorption, so that it exhibits good photocatalytic performance and repeatability in photocatalytic CO2 reduction. By combining SI-XPS and SI-XRD techniques, the photogenerated charge migration, element valence state and dynamic crystal structure evolution of the two-dimensional copper sulfide molybdenum nanosheet are monitored in real time under light excitation conditions, revealing the crystal structure evolution of the two-dimensional copper sulfide molybdenum nanosheet during the photocatalytic CO2 reduction process and the mutual influence and interaction between the photogenerated charge migration and the surface atomic structure and crystal structure, and also explaining the intrinsic mechanism of its photocatalytic CO2 reduction. The photocatalytic CO2 reduction products CO and C2H4 were also detected, and the CO and C2H4 yields were calculated, indicating that the layered bimetallic sulfide nanomaterial provided by the embodiment of the present invention has the advantages of high efficiency, good selectivity and stable performance for photocatalytic CO2 reduction reaction.
[0036] The features and performance of the present invention are further described in detail below with reference to the embodiments.
[0037] Example 1
[0038] A method for preparing a layered bimetallic site copper molybdenum sulfide (Cu2MoS4) nanomaterial comprises the following steps:
[0039] (1) First, Cu2O nanocrystals were synthesized. Typically, 0.171 g of copper chloride (H2O) and 3.333 g of polyvinylpyrrolidone (PVP) were dissolved in 100 mL of deionized water; the mixture was then stirred under magnetic stirring for 20 minutes, and then a 2.0 M NaOH aqueous solution (10.0 mL) was added to the solution and stirred for 10 minutes. An ascorbic acid aqueous solution (10.0 mL) was then added to the mixed solution. After stirring for 1 hour, the product was collected by centrifugation and washed several times with deionized water and absolute ethanol during the centrifugation process; finally, it was dried in vacuum at 60°C for several hours.
[0040] (2) Dissolve 60 mg of sodium molybdate (Na2MoO4·2H2O) and 120 mg of thioacetamide (C2H5NS) in 20 ml of ethylene glycol, then add 40 mg of the Cu2O powder synthesized in step (1) and disperse it in the mixed solution using ultrasound for 10 minutes. The mixed solution changes from yellow to dark brown. After the hydrothermal reaction, the solid powder is collected by centrifuge, washed several times with deionized water and ethanol, and dried in a vacuum oven for several hours. Cu2MoS4 nanosheets are thus prepared.
[0041] The TEM image of the layered bimetallic sulfide nanomaterial prepared in Example 1 is shown in FIG. Figure 1 ,from Figure 1 It can be seen that the thickness of the Cu2MoS4 nanosheets prepared in this example is about 20nm, the lateral size is 2μm, and the longitudinal size is 2μm. The yield of CO2 reduction under visible light conditions for layered bimetallic sulfide nanomaterials and the materials obtained in the comparative example is shown in FIG. Figure 2 ,from Figure 2 It can be seen that the layered bimetallic sulfide nanomaterial prepared in this embodiment produces not only C1 product CO but also C2 product C2H4 in the photocatalytic reduction of CO2 under visible light conditions, and the CO yield of this material is higher than that of Cu2S / MoS2 heterojunction, Cu2S and MoS2. When Cu2S / MoS2 heterojunction, Cu2S and MoS2 are used for photocatalytic CO2 reduction, no C2H4 is produced. The UV-visible spectrum of the Cu2MoS4 nanosheets prepared in this embodiment can be found in Figure 3 ,from Figure 3 It can be seen from the figure that the spectral absorption band edge of the layered bimetallic sulfide nanomaterial obtained in this embodiment is 710nm. The time-resolved instantaneous photoluminescence spectrum is shown in FIG. Figure 4 ,from Figure 4 It can be seen from the figure that the time-resolved transient photoluminescence (TS-PL) fluorescence lifetime of the layered bimetallic sulfide nanomaterial prepared in this example is 51.48 ns.
[0042] Example 2
[0043] To prepare the photoelectrode, 5 mg of the prepared catalyst and 20 μL of Nafion solution (5 wt%) were dispersed in 1 mL of a mixed solvent containing isopropanol and water (1:3 v / v), and a uniform catalyst system was formed by ultrasonic treatment. Then, 40 μL of the catalyst was evenly spin-coated on a pretreated FTO (1.0 × 1.0 cm -2 ) and dried in air at room temperature to form photocatalyst-modified FTO. All photoelectrochemical measurements were performed in a three-electrode one-chamber photoelectrochemical cell (CHI660d electrochemical workstation) at room temperature. -2 ) as the counter electrode, saturated potassium chloride silver chloride electrode (Ag / AgCl) as the reference electrode, and the prepared sample as the working electrode. - 1 Na2SO4 and 0.1molL -1 The layered copper molybdenum sulfide nanomaterial was subjected to an amperometric curve test in a mixed solution of Na2SO3. The test results showed that the prepared photoelectrode material had a good photocurrent response, further demonstrating its excellent photocatalytic CO2 reduction performance.
[0044] Example 3
[0045] 5 mg of copper molybdenum sulfide photocatalyst was ultrasonically dispersed in 400 μl of deionized water, and then the suspension was dispersed on a glass fiber membrane. The glass fiber membrane was suspended in a 200 ml quartz glass reactor. The instrument was initially vacuum treated and then evacuated with 0.1 MPa high-purity carbon dioxide gas, and the gas washing was repeated 3 times. The reaction temperature was maintained at around 20°C. A 300W short-arc Xe lamp equipped with a visible light filter was used as a visible light source. Finally, the collected gas was qualitatively and quantitatively determined by gas chromatography (GC). The layered copper molybdenum sulfide nanosheet material photocatalytically reduced CO2 to C1 product CO under visible light conditions with a yield of 10.83 μmol g -1 Meanwhile, the yield of C2 product C2H4 was 6.78 μmol g -1 .
[0046] Comparative Example 1
[0047] A method for preparing a single-metal site copper sulfide nanomaterial comprises the following steps: first, synthesizing Cu2O nanocrystals in the same manner as in Example 1, then dissolving 120 mg of thioacetamide (C2H5NS) in 20 ml of ethylene glycol, then adding 40 mg of the Cu2O powder synthesized in step (1), and dispersing the mixture in the solution using ultrasound for 10 minutes. The mixture changes from yellow to dark brown. Then, a hydrothermal reaction is carried out at 200°C for 24 hours. After the hydrothermal reaction is completed, the resulting solid powder is collected by centrifuge, washed several times with deionized water and ethanol, and dried in a vacuum oven for several hours.
[0048] Comparative Example 2
[0049] A method for preparing a bimetallic site heterojunction nanomaterial comprises the following steps: first, synthesizing Cu2O nanocrystals in the same manner as in Example 1, then dissolving 60 mg of sodium molybdate (Na2MoO4·2H2O) and 120 mg of thioacetamide (C2H5NS) in 20 ml of ethylene glycol, then adding 40 mg of the Cu2O powder synthesized in step (1), and dispersing the mixture in the mixed solution using ultrasound for 10 minutes. The mixed solution changes from yellow to dark brown. Then, a hydrothermal reaction is carried out at 200°C for 24 hours. After the hydrothermal reaction is completed, the obtained solid powder is collected by a centrifuge, washed several times with deionized water and ethanol, and dried in a vacuum oven for several hours. The obtained solid powder is annealed in a tube furnace at 1000°C for 10 hours to obtain a Cu2S / MoS2 heterojunction.
[0050] Comparative Example 3
[0051] A method for preparing a single-metal site molybdenum sulfide nanomaterial comprises the following steps: first, dissolving 60 mg of sodium molybdate (Na2MoO4·2H2O) and 120 mg of thioacetamide (C2H5NS) in 20 ml of ethylene glycol, then dispersing them in the mixed solution using ultrasound for 10 minutes, and then performing a hydrothermal reaction at 200°C for 24 hours. After the hydrothermal reaction is completed, the resulting solid powder is collected using a centrifuge, washed several times with deionized water and ethanol, and dried in a vacuum oven for several hours.
[0052] Comparative Example 4
[0053] A method for preparing a layered bimetallic copper molybdenum sulfide (Cu2MoS4) nanomaterial comprises the following steps: first, synthesizing Cu2O nanocrystals in the same manner as in Example 1; then dissolving 60 mg of sodium molybdate (Na2MoO4·2H2O) and 120 mg of L-cysteine in 20 ml of ethylene glycol; then adding 40 mg of the Cu2O powder synthesized in step (1); and dispersing the Cu2O powder in the mixed solution using ultrasound for 10 minutes; then performing a hydrothermal reaction at 200°C for 24 hours; and after completion of the hydrothermal reaction, collecting the resulting solid powder using a centrifuge, washing it several times with deionized water and ethanol, and drying it in a vacuum oven for several hours.
[0054] Comparative Example 5
[0055] A method for preparing a layered bimetallic site copper molybdenum sulfide (Cu2MoS4) nanomaterial comprises the following steps: first, synthesizing Cu2O nanocrystals in the same manner as in Example 1; then dissolving 60 mg of sodium molybdate (Na2MoO4·2H2O) and 120 mg of thiourea in 20 ml of ethylene glycol; then adding 40 mg of the Cu2O powder synthesized in step (1); and dispersing the powder in the mixed solution using ultrasound for 10 minutes; then performing a hydrothermal reaction at 200°C for 24 hours; and after completion of the hydrothermal reaction, collecting the resulting solid powder using a centrifuge, washing it several times with deionized water and ethanol, and drying it in a vacuum oven for several hours.
[0056] The experimental results are shown in Table 1:
[0057] Table 1
[0058] project CO production / μmol / g <![CDATA[C2H4 production / μmol / g]]> Example 1 10.83 6.78 Comparative Example 1 7.23 0 Comparative Example 2 6.40 0 Comparative Example 3 7.41 0 Comparative Example 4 5.52 2.43 Comparative Example 5 4.43 1.28
[0059] It can be seen from Table 1 above that the layered bimetallic sulfide nanomaterials prepared according to Example 1 have the highest production of CO and C2H4 in photocatalytic CO2 reduction. When Cu2S / MoS2 heterojunction, Cu2S and MoS2 are used for photocatalytic CO2 reduction, no C2H4 is produced.
[0060] In summary, the embodiments of the present invention provide a layered bimetallic sulfide nanomaterial, a preparation method and application thereof. The layered bimetallic sulfide nanomaterial is a layered bimetallic site copper molybdenum sulfide (Cu2MoS4) nanosheet material, the thickness of the nanosheet is 20-30nm, the lateral size is 1-2μm, and the longitudinal size is 1-2μm. The photocatalytic material is synthesized by a simple one-step hydrothermal method. The layered material is used as a catalyst in the photocatalytic CO2 reduction process, and is used in the process of photocatalytic reduction of CO2 under visible light. Compared with the prior art, the present invention uses in-situ monitoring means to explain the mechanism, and prepares layered copper molybdenum sulfide nanosheets and applies them to photocatalytic CO2 reduction. The method is simple and easy, the preparation process is cheap and the reaction conditions are mild. The photocatalytic CO2 reduction products of the layered copper molybdenum sulfide nanosheet material under visible light conditions include not only the C1 product CO, but also the C2 product C2H4. The material has a high CO yield, and the comparative examples have no C2H4, which proves that the layered bimetallic site copper molybdenum sulfide (Cu2MoS4) nanosheet material provided by the embodiment of the present invention exhibits excellent photocatalytic performance when used for photocatalytic reduction of CO2, and has good application prospects.
[0061] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.
Claims
1. Application of a layered bimetallic sulfide nanomaterial in photocatalytic reduction of CO2, characterized in that: The layered bimetallic sulfide nanomaterial is a two-dimensional layered Cu2MoS4 nanosheet, wherein the thickness of the nanosheet is 20-30 nm, the lateral size is 1-2 μm, and the longitudinal size is 1-2 μm; The preparation method of the layered bimetallic sulfide nanomaterial includes: sealing and heating a mixture of cuprous oxide nanocrystals, a molybdenum source, a sulfur source and ethylene glycol to react to obtain the two-dimensional layered Cu2MoS4 nanosheets, wherein the sulfur source is selected from thioacetamide.
2. The use according to claim 1, characterized in that The layered bimetallic sulfide nanomaterial has a spectral absorption band edge of 710 nm and an optical band gap of 1.75 eV.
3. The use according to claim 1, characterized in that The time-resolved instantaneous photoluminescence lifetime of the layered bimetallic sulfide nanomaterial is 51.48 ns.
4. The use according to claim 1, characterized in that The sealed heating reaction is carried out at a temperature of 100-210° C. and for a time of 2-24 h.
5. The use according to claim 1, characterized in that The preparation method of the layered bimetallic sulfide nanomaterial also includes: after sealing and heating for reaction, collecting solid powder through solid-liquid separation, washing the solid powder with deionized water and ethanol several times, and then drying to obtain the two-dimensional layered Cu2MoS4 nanosheets.
6. The use according to claim 5, characterized in that The drying temperature is 40-100° C. and the drying time is 6-12 hours.
7. The use according to claim 1, characterized in that The mass ratio of cuprous oxide nanocrystals, molybdenum source, sulfur source and ethylene glycol is (1-2): (1-3): (4-6): (1-2).
8. The use according to claim 1, characterized in that The molybdenum source is selected from sodium molybdate.
9. The use according to claim 1, characterized in that The cuprous oxide nanocrystals are obtained by the following method: dissolving a copper salt and a surfactant in water, adjusting the pH value of the solution to a strong alkaline value, and then adding a reducing agent to react to obtain the cuprous oxide nanocrystals.
10. The use according to claim 9, characterized in that The copper salt is selected from one or more of copper chloride, copper nitrate and copper sulfate; the surfactant is selected from polyvinyl pyrrolidone; and the reducing agent is selected from one or more of ascorbic acid, hydrazine and hydroxylamine hydrochloride.
11. The use according to claim 9, characterized in that The mass ratio of the copper salt to the surfactant is 1:(10-20); the molar ratio of the copper salt to the reducing agent is 1:(1-6).
12. The use according to claim 1, characterized in that During the photocatalytic reduction of CO2, a continuous flow system reactor was used to conduct the reduction experiment, a 300W xenon lamp was used as the light source, and the product components were analyzed by a mass spectrometer and a gas chromatograph.
13. The use according to claim 12, characterized in that Under the condition of light with a wavelength of 420 nm, the two-dimensional layered Cu2MoS4 nanosheets can photocatalytically reduce CO2 with a C2H4 yield of 6.78 μmol / h / g and a CO yield of 10.83 μmol / h / g.