Mn 0.5 Cd 0.5 Preparation method of S / CaTiO3 / Ni3C material and application of the material in photocatalytic nitrogen fixation
By introducing Ni3C cocatalysts onto Mn0.5Cd0.5S and CaTiO3 to form an S-type heterostructure, the problem of electron-hole recombination in MnxCd1-xS photocatalysts was solved, achieving a highly efficient photocatalytic nitrogen fixation effect and solving the problems of high energy consumption and environmental pollution in traditional ammonia synthesis processes.
Patent Information
- Application Number
- CN202310638828.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-06-01
- Publication Date
- 2025-12-12
- Estimated Expiration
- 2043-06-01
AI Technical Summary
The rapid recombination of electron and hole pairs in the photocatalytic reaction of existing MnxCd1-xS photocatalysts severely affects their activity, and the traditional ammonia synthesis process is subject to harsh conditions, high energy consumption, and serious environmental pollution.
Nanoparticle-sized Ni3C was used as a cocatalyst to form an S-type heterostructure with Mn0.5Cd0.5S and CaTiO3, thus constructing a composite photocatalyst. This improved the separation efficiency of electrons and holes, and the loaded Ni3C served as an electron-capturing center, providing more reactive sites.
The photocatalytic nitrogen fixation performance was significantly improved, with the nitrogen fixation rate of the photocatalyst increasing from 23 µmol g⁻¹ h⁻¹ to 1208 µmol g⁻¹ h⁻¹, demonstrating good photocatalytic activity and stability.
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Figure CN117772245B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of composite photocatalytic materials, and particularly relates to a Mn 0.5 Cd 0.5 S / CaTiO3 / Ni3C material, a preparation method thereof and application of the material in photocatalytic nitrogen fixation. BACKGROUND
[0002] In today's society, energy supply shortage and environmental pollution are still the main problems faced by human beings. In recent years, energy sources mainly rely on fossil fuels or coal, which is irreversible and seriously damages the environment, and scientists are committed to finding a clean renewable energy to replace fossil energy, so as to solve the problems of global energy depletion and environmental pollution. Ammonia, as one of the most common nitrogen-containing compounds, is an indispensable precursor for the production of fertilizers, synthetic fibers and medicines, and is widely used in agriculture, medicine, textile and other industries. Due to the advantages of almost 2 times energy density of liquid hydrogen, liquefaction at -10℃ under low pressure, safety and less energy loss, it is convenient to store and transport, and is considered as an ideal hydrogen storage intermediate and zero-carbon fuel, which can meet the global population growth and economic demand. At present, the production of ammonia mainly relies on the traditional Haber-Bosch process under high temperature and high pressure (400-500℃, 150-250atm), which has harsh reaction conditions, high equipment requirements and energy consumption accounting for about 1%-2% of human annual energy consumption, and at the same time, about 300 million tons of CO2 are released, which aggravates resource waste and serious environmental pollution. Therefore, it is very important to design a green and sustainable ammonia synthesis path using renewable energy. Nitrogen, as the main component of air, has a high volume fraction of 78%, and the reduction of nitrogen to ammonia, i.e. nitrogen reduction reaction, has attracted widespread attention.
[0003] So far, researchers have developed and designed many high-activity solid nitrogen photocatalysts such as oxides, sulfides, nitrides and carbides. Mn x Cd 1-x S solid solution, as a metal sulfide, has excellent performance in photocatalytic nitrogen fixation, dye-sensitized solar cells and supercapacitors, and has attracted widespread attention from researchers in recent years. Mn x Cd 1-x S has the advantages of narrow band gap and high flat potential, and can also effectively transfer charges through the intermediate sulfur atoms bonded to other metals at the interface. Although Mn x Cd 1-x S has a suitable band gap and a high conduction band position, however, the rapid recombination of electron-hole pairs during the photocatalytic reaction process seriously affects the photocatalytic activity of Mn x Cd 1-x S. In order to improve the photocatalytic activity of Mn x Cd1-x Cd x Cd 1-x Cd 0.5 Cd 0.5 Cd 0.5 Cd 0.5 Cd 0.5 Cd 0.5 Cd SUMMARY
[0004] The application aims to provide a Mn 0.5 Cd 0.5 Cd 0.5 Cd 0.5 Cd
[0005] The application realizes the above-mentioned purpose by adopting the following technical scheme, a Mn 0.5 Cd 0.5 Cd 0.5 Cd 0.5 Cd 0.5 Cd 0.5 Cd 0.5 Cd 0.5The mass ratio of S, CaTiO3 and Ni3C is 1:0.01-0.2:0.01-0.1; XRD has diffraction peaks at 26.67°, 44.17° and 52.18°; XPS has binding energies at 640.55 eV, 651.98 eV, 404.61 eV, 411.34 eV, 161.26 eV, 162.35 eV, 346.39 eV, 350.30 eV, 458.18 eV, 464.10 eV, 529.47 eV, 531.21 eV, 852.32 eV, 855.19 eV, 860.09 eV, 872.71 eV, 878.54 eV, 284.69 eV, 286.13 eV and 288.26 eV; Mn 0.5 Cd 0.5 S and Ni3C are both in nanoparticle structure, and CaTiO3 is in nanosheet structure.
[0006] It can be clearly observed from the XRD data analysis graph that pure Mn 0.5 Cd 0.5 S has three diffraction peaks at 26.67°, 44.17° and 52.18°, corresponding to (111) crystal face, (220) crystal face and (311) crystal face respectively, and Mn 0.5 Cd 0.5 The XRD spectrum of S is consistent with the related literature reported before, indicating that Mn 0.5 Cd 0.5 S sample is successfully synthesized. Pure CaTiO3 can be clearly observed from the graph to have very obvious diffraction peaks at 23.23°, 33.11°, 39.1°, 40.67°, 44.15°, 47.49°, 51.99°, 53.53°, 54.68°, 59.36°, 69.48° and 79.1°, corresponding to (101), (121), (103), (022), (122), (040), (123), (222), (131), (042), (242) and (161) crystal faces of orthorhombic CTO respectively, and corresponding to the standard card (JCPDS no. 78-1013), without other impurity peaks. Pure Ni3C can be clearly observed from the graph to have obvious diffraction peaks at 39.17°, 41.65°, 44.66°, 58.66°, 71.07° and 78.15°, corresponding to (110), (006), (113), (116), (300) and (119) crystal faces of hexagonal Ni3C respectively, and corresponding to the standard card (JCPDS no. 72-1467), without other impurity peaks. Mn 0.5 Cd 0.5 S / CaTiO3 / Ni3C sample has Mn 0.5 Cd0.5 S, but no CaTiO3and Ni3C diffraction peaks were observed in the diffraction pattern, which may be due to the low content of CaTiO3and Ni3C or the too weak CaTiO3and Ni3C diffraction peaks.
[0007] XPS analysis of Mn 0.5 Cd 0.5 The elemental composition in the S / CaTiO3 / Ni3C sample can be seen from the spectrum that the binding energy of Mn 2p 3 / 2 and Mn 2p 1 / 2 is 640.55 eV and 651.98 eV, the binding energy of Cd 3d 5 / 2 and Cd 3d 3 / 2 is 404.61 eV and 411.34 eV, the binding energy of S 2p 3 / 2 and S 2p 1 / 2 is 161.26 eV and 162.35 eV, indicating that the sample contains Mn elements, Cd elements and S elements. The binding energy of Ca 2p 3 / 2 and Ca 2p 1 / 2 in the spectrum is 346.39 eV and 350.30 eV, the binding energy of Ti 2p 3 / 2 and Ti 2p 1 / 2 is 458.18 eV and 464.10 eV, and the binding energy of O is 529.47 eV and 531.21 eV, indicating that the sample contains Ca elements, Ti elements and O elements. The binding energy of Ni 0 , Ni 2p 3 / 2 and Ni 2p 1 / 2 in the spectrum is 852.32 eV, 855.19 eV and 872.71 eV, and the binding energy of C is 284.69 eV, 286.13 eV and 288.26 eV. XPS spectrum observes that the three system composite materials contain Mn, Cd, S, Ca, Ti, O, Ni and C elements, which further proves the successful preparation of Mn 0.5 Cd 0.5 S / CaTiO3 / Ni3C composite photocatalytic material.
[0008] SEM analysis of the morphology of the sample, from the figure, it can be seen that Mn 0.5 Cd 0.5 S is composed of irregular nanoparticles; the sample CaTiO3is composed of irregular nanosheets; the morphology of the sample Mn 0.5 Cd 0.5 S is similar, and the sample Ni3C is also composed of nanoscale spherical nanoparticles.
[0009] Mn 0.5 Cd 0.5The S / CaTiO3 / Ni3C composite photocatalyst is characterized by XRD and XPS, the XRD characterization shows that there is Mn 0.5 Cd 0.5 S diffraction peak, and no other impurity peak is found, which indicates that the prepared sample has high purity; meanwhile, since the loading amount of CaTiO3 and Ni3C is small, the diffraction peaks of CaTiO3 and Ni3C are not detected. The XPS characterization shows that the prepared Mn 0.5 Cd 0.5 S / CaTiO3 / Ni3C composite photocatalyst contains Mn, Cd, S, Ca, Ti, O, Ni and C elements, which further confirms that the prepared Mn 0.5 Cd 0.5 S / CaTiO3 / Ni3C composite photocatalyst contains Mn 0.5 Cd 0.5 S, CaTiO3 and Ni3C exist.
[0010] The preparation method of the composite photocatalyst provided by the application is as follows:
[0011] Mn 0.5 Cd 0.5 The preparation method of the S / CaTiO3 / Ni3C material, characterized in that it comprises the following steps:
[0012] 1) Dissolve calcium nitrate, tetrabutyl titanate and sodium hydroxide in deionized water, and perform hydrothermal reaction on the solution at 160-250 DEG C, and obtain CaTiO3 nanosheet after treatment;
[0013] Further, in the above technical solution, the molar ratio of calcium nitrate to tetrabutyl titanate is 1:1;
[0014] 2) Dissolve nickel acetate in oleylamine, and perform hydrothermal reflux reaction on the solution at 160-250 DEG C under nitrogen atmosphere, and obtain Ni3C nanoparticles after treatment;
[0015] Further, in the above technical solution, the molar ratio of nickel acetate to oleylamine is 1:20;
[0016] 3) Disperse manganese acetate, cadmium acetate, thioacetamide and the CaTiO3 nanosheet obtained in step 1) in deionized water, and perform hydrothermal reaction on the obtained mixed solution at 160-250 DEG C after vigorous stirring, and obtain Mn 0.5 Cd 0.5 S / CaTiO3 composite after treatment;
[0017] Further, in the above technical solution, the molar ratio of manganese acetate, cadmium acetate and thioacetamide is 1:1:2; the obtained Mn 0.5 Cd 0.5Mn in S / CaTiO3 composite 0.5 Cd 0.5 The mass ratio of S and CaTiO3 is 1:0.01-0.2;
[0018] 4) The Ni3C nanoparticles obtained in step 2) and the Mn 0.5 Cd 0.5 S / CaTiO3 composite is dispersed in an alkaline aqueous solution, and is subjected to ultrasonic and stirring treatment, and the Mn 0.5 Cd 0.5 S / CaTiO3 / Ni3C ternary composite photocatalyst is obtained after the treatment.
[0019] The Mn 0.5 Cd 0.5 S / CaTiO3 / Ni3C ternary composite photocatalyst prepared according to the above method is subjected to a photocatalytic nitrogen fixation experiment:
[0020] Operation conditions: light source: 300W xenon lamp; amount of catalyst: 0.02g; amount of deionized water: 90mL; amount of methanol: 10mL; flow rate of N2: 20mL / min, pure Mn 0.5 Cd 0.5 S photocatalytic nitrogen fixation rate is 23µmol g -1 h -1 , and the Mn 0.5 Cd 0.5 S / CaTiO3 / Ni3C ternary composite photocatalyst photocatalytic nitrogen fixation rate is 1208µmol g -1 h -1 , which shows obviously enhanced photocatalytic nitrogen fixation performance.
[0021] The present application has the following beneficial effects: The Mn 0.5 Cd 0.5 S / CaTiO3 / Ni3C composite photocatalyst prepared by the present application has the following beneficial effects: The semiconductor Mn 0.5 Cd 0.5 S and the semiconductor CaTiO3 first form an S-type heterojunction, which not only accelerates the directional movement and separation of photo-generated electrons and holes, but also maintains strong oxidation-reduction ability of photo-generated charge carriers; in addition, on the basis of the S-type heterojunction, the Ni3C cocatalyst is loaded, the Ni3C nanoparticle cocatalyst as an electron capture center not only can provide more reaction active sites, but also can further improve the charge separation efficiency, so that the finally prepared Mn 0.5 Cd 0.5 S / CaTiO3 / Ni3C composite photocatalyst has greatly improved photocatalytic nitrogen fixation performance. BRIEF DESCRIPTION OF DRAWINGS
[0022] Figure 1 Mn prepared in Example 1 0.5 Cd 0.5 S, CaTiO3, Ni3C and Mn 0.5 Cd 0.5 XRD pattern of S / CaTiO3 / Ni3C;
[0023] Figure 2 Mn prepared in Example 1 0.5 Cd 0.5 XPS pattern of S / CaTiO3 / Ni3C;
[0024] Figure 3 Mn prepared in Example 1 0.5 Cd 0.5 S, CaTiO3, Ni3C and Mn 0.5 Cd 0.5 SEM image of S / CaTiO3 / Ni3C;
[0025] Figure 4 Mn prepared in Example 1 0.5 Cd 0.5 S, Mn 0.5 Cd 0.5 S / CaTiO3, Mn 0.5 Cd 0.5 Photocatalytic nitrogen fixation effect diagram of S / CaTiO3 / Ni3C. DETAILED DESCRIPTION
[0026] The above content of the present application is further illustrated in detail by the following examples, but this should not be understood as the scope of the above subject matter of the present application being limited to the following examples only, and any technology realized based on the above content of the present application falls within the scope of the present application. EXAMPLE
[0027] 1) Preparation of CaTiO3 nanosheet: 8 mmol of Ca(NO3)2·4H2O, 8 mmol of tetrabutyl titanate and 0.8 g of NaOH were sequentially weighed and dissolved in 30 mL of deionized water, and the solution was subjected to hydrothermal reaction at 160°C for 24 h. After the reaction was completed and cooled to room temperature, centrifugation was performed, and the collected solid sample was transferred to a vacuum drying oven and dried at 60°C for 12 h to obtain CaTiO3 nanosheet.
[0028] 2) Preparation of Ni3C nanoparticles: 2 mmol of nickel acetate was dissolved in 14 mL of oleylamine solution. Under a nitrogen atmosphere, the solution was subjected to hydrothermal reflux reaction at 160°C for 2 h. After the reaction was completed and cooled to room temperature, centrifugation was performed. The collected solid sample was transferred to a vacuum drying oven and dried at 60°C for 12 h to obtain Ni3C nanoparticles.
[0029] 3) Preparation of Mn 0.5 Cd 0.5 S / CaTiO3 composite sample: 5 mmol of Mn(CH3COO)2·4H2O, 5 mmol of Cd(CH3COO)2·2H2O and 10 mmol of CH3CSNH2 were sequentially weighed and dissolved in 40 mL of deionized water. After complete dissolution, 0.01 g of CaTiO3 nanosheets obtained in step 1) was added, and the mixture was stirred vigorously for 1 h. The resulting mixture solution was then transferred to a hydrothermal reactor and subjected to hydrothermal reaction at 160°C for 24 h. After the reaction was completed and cooled to room temperature, suction filtration was performed. The collected solid sample was transferred to a vacuum drying oven and dried at 60°C for 12 h to obtain Mn 0.5 Cd 0.5 S / CaTiO3 composite.
[0030] 4) Preparation of Mn 0.5 Cd 0.5 S / CaTiO3 / Ni3C composite photocatalyst: 0.1 g of Mn 0.5 Cd 0.5 S / CaTiO3 composite obtained in step 3) and 1 mg of Ni3C nanoparticles obtained in step 2) were mixed and dispersed in 50 mL of dilute NaOH aqueous solution and ultrasonicated for 2 h. Subsequently, the solution was continuously stirred for 10 h. The obtained product was washed by suction filtration with deionized water and anhydrous ethanol, and vacuum dried to obtain Mn 0.5 Cd 0.5 S / CaTiO3 / Ni3C ternary composite photocatalyst.
[0031] From Figure 1 it can be clearly seen that Mn 0.5 Cd 0.5 S / CaTiO3 / Ni3C ternary composite photocatalyst contains Mn 0.5 Cd 0.5 S and CaTiO3, and no diffraction peaks of other substances were found, indicating that the prepared Mn 0.5 Cd 0.5The S and CaTiO3 samples have high purity. However, no diffraction peaks of Ni3C are observed in the diffraction pattern, which may be due to the low content of Ni3C or the diffraction peaks of Ni3C nanoparticles being too weak. The successful loading of Ni3C nanoparticles can be further confirmed by XPS.
[0032] It can be seen from Figure 2 that the prepared Mn 0.5 Cd 0.5 S / CaTiO3 / Ni3C sample contains Mn, Cd, S, Ca, Ti, O, Ni and C elements, further confirming that Mn 0.5 Cd 0.5 S, CaTiO3 and Ni3C exist in the sample.
[0033] It can be seen from Figure 3 that Mn 0.5 Cd 0.5 S nanoparticles and Ni3C nanoparticles are stacked on the CaTiO3 nanosheet, thereby forming a tight contact interface, proving that the ternary composite photocatalyst Mn 0.5 Cd 0.5 S / CaTiO3 / Ni3C is successfully prepared.
[0034] It can be seen from Figure 4 that the photocatalytic nitrogen fixation performance of the prepared ternary system Mn 0.5 Cd 0.5 S / CaTiO3 / Ni3C sample is significantly higher than that of Mn 0.5 Cd 0.5 S and Mn 0.5 Cd 0.5 S / CaTiO3 sample, indicating that the construction of S heterostructure and the introduction of cocatalyst Ni3C effectively enhance the photocatalytic nitrogen fixation performance of Mn 0.5 Cd 0.5 S sample. Example
[0035] 1) Preparation of CaTiO3 nanosheet: 8 mmol of Ca(NO3)2·4H2O, 8 mmol of tetrabutyl titanate and 0.8 g of NaOH were sequentially weighed and dissolved in 30 mL of deionized water, and the solution was subjected to hydrothermal reaction at 200°C for 24 h. After the reaction was completed and cooled to room temperature, centrifugation was performed, and the collected solid sample was transferred to a vacuum drying oven and dried at 60°C for 12 h to obtain CaTiO3 nanosheet.
[0036] 2) Preparation of Ni3C nanoparticles: 2 mmol of nickel acetate was dissolved in 14 mL of oleylamine solution, and the solution was subjected to hydrothermal reflux reaction at 200°C for 2 h under a nitrogen atmosphere. After the reaction was completed and cooled to room temperature, centrifugation was performed, and the solid sample was washed with deionized water and anhydrous ethanol three times, respectively. The collected solid sample was transferred to a vacuum drying oven and dried at 60°C for 12 h to obtain Ni3C nanoparticles.
[0037] 3) Preparation of Mn 0.5 Cd 0.5 S / CaTiO3 composite sample: 5 mmol of Mn(CH3COO)2·4H2O, 5 mmol of Cd(CH3COO)2·2H2O, and 10 mmol of CH3CSNH2 were sequentially weighed and dissolved in 40 mL of deionized water. After complete dissolution, 0.1 g of CaTiO3 nanosheets obtained in step 1) was added, and the mixture was stirred vigorously for 1 h. The resulting mixture solution was then transferred to a hydrothermal reactor and subjected to hydrothermal reaction at 200°C for 24 h. After the reaction was completed and cooled to room temperature, suction filtration was performed, and the solid sample was washed with deionized water and anhydrous ethanol three times, respectively. The collected solid sample was transferred to a vacuum drying oven and dried at 60°C for 12 h to obtain Mn 0.5 Cd 0.5 S / CaTiO3 composite.
[0038] 4) Preparation of Mn 0.5 Cd 0.5 S / CaTiO3 / Ni3C composite photocatalyst: 0.1 g of Mn 0.5 Cd 0.5 S / CaTiO3 composite obtained in step 3) and 5 mg of Ni3C nanoparticles obtained in step 2) were mixed and dispersed in 50 mL of dilute NaOH aqueous solution, and ultrasonic treatment was performed for 2 h. Subsequently, the solution was continuously stirred for 10 h, and the obtained product was washed by suction filtration with deionized water and anhydrous ethanol. After vacuum drying, Mn 0.5 Cd 0.5 S / CaTiO3 / Ni3C ternary composite photocatalyst was obtained. Example
[0039] 1) Preparation of CaTiO3 nanosheets: 8 mmol of Ca(NO3)2·4H2O, 8 mmol of tetrabutyl titanate, and 0.8 g of NaOH were sequentially weighed and dissolved in 30 mL of deionized water. The solution was subjected to hydrothermal reaction at 250°C for 24 h. After the reaction was completed and cooled to room temperature, centrifugation was performed, and the solid sample was washed with dilute acetic acid, deionized water, and anhydrous ethanol three times, respectively. The collected solid sample was transferred to a vacuum drying oven and dried at 60°C for 12 h to obtain CaTiO3 nanosheets.
[0040] 2) Preparation of Ni3C nanoparticles: 2 mmol of nickel acetate was dissolved in 14 mL of oleylamine solution, under the atmosphere of nitrogen, the solution was subjected to hydrothermal reflux reaction at 250°C for 2 h, after the reaction was completed and cooled to room temperature, centrifugation was carried out, and then washed with deionized water and anhydrous ethanol for three times, respectively, the collected solid sample was transferred to a vacuum drying oven and dried at 60°C for 12 h to obtain Ni3C nanoparticles.
[0041] 3) Preparation of Mn 0.5 Cd 0.5 S / CaTiO3 composite sample: 5 mmol of Mn(CH3COO)2·4H2O, 5 mmol of Cd(CH3COO)2·2H2O and 10 mmol of CH3CSNH2 were sequentially weighed and dissolved in 40 mL of deionized water, after complete dissolution, 0.2 g of CaTiO3 nanosheets obtained in step 1) was added, and after 1 h of vigorous stirring, the obtained mixed solution was transferred to a hydrothermal reactor and subjected to hydrothermal reaction at 250°C for 24 h, after the reaction was completed and cooled to room temperature, suction filtration was carried out, and then washed with deionized water and anhydrous ethanol for three times, respectively, the collected solid sample was transferred to a vacuum drying oven and dried at 60°C for 12 h to obtain Mn 0.5 Cd 0.5 S / CaTiO3 composite.
[0042] 4) Preparation of Mn 0.5 Cd 0.5 S / CaTiO3 / Ni3C composite photocatalyst: 0.1 g of Mn 0.5 Cd 0.5 S / CaTiO3 composite obtained in step 3) and 10 mg of Ni3C nanoparticles obtained in step 2) were mixed and dispersed in 50 mL of dilute NaOH aqueous solution, and ultrasonic treatment was carried out for 2 h, then the solution was continuously stirred for 10 h, and the obtained product was washed by suction filtration with deionized water and anhydrous ethanol, and vacuum dried to obtain Mn 0.5 Cd 0.5 S / CaTiO3 / Ni3C ternary composite photocatalyst. Example
[0043] Photocatalytic nitrogen fixation experiment:
[0044] Operating conditions: light source: 300 W xenon lamp; amount of catalyst: 0.02 g; amount of deionized water: 90 mL; amount of methanol: 10 mL. From Figure 4 it can be known that the photocatalytic nitrogen fixation rate of pure Mn 0.5 Cd 0.5 S is 23 µmol g -1 h -1 , while the photocatalytic nitrogen fixation rate of Mn 0.5 Cd 0.5The photocatalytic nitrogen fixation rate of the S / CaTiO3 / Ni3C ternary composite photocatalyst reaches 1208 µmol g. -1 h -1 It exhibits significantly enhanced photocatalytic nitrogen fixation performance. Combined with... Figures 1-4 The results indicate that Mn with enhanced photocatalytic nitrogen fixation performance has been successfully prepared. 0.5 Cd 0.5 S / CaTiO3 / Ni3C composite photocatalyst.
[0045] The Mn prepared using the same methods as in Examples 2-3 0.5 Cd 0.5 The S / CaTiO3 / Ni3C ternary composite photocatalyst also achieved similar nitrogen fixation effects.
[0046] The above embodiments describe the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are only illustrative of the principles of the present invention. Various changes and modifications can be made to the present invention without departing from the scope of the principles of the present invention, and all such changes and modifications fall within the protection scope of the present invention.
Claims
1. Mn 0.5 Cd 0.5 The application of S / CaTiO3 / Ni3C material in photocatalytic nitrogen fixation is characterized in that: The photo-generated electrons on the conduction band of the semiconductor CaTiO3 are transferred to the surface of the cocatalyst Ni3C through the band bending and built-in electric field, so that more photo-generated electrons with strong reducing property are involved in the reduction reaction to reduce N2 into NH4 0.5 Cd 0.5 S valence band holes are combined, while the photo-generated electrons on the conduction band of the semiconductor Mn 0.5 Cd 0.5 S are transferred to the surface of the cocatalyst Ni3C, so that more photo-generated electrons with strong reducing property are involved in the reduction reaction to reduce N2 into NH4 + ; the Mn 0.5 Cd 0.5 S / CaTiO3 / Ni3C material takes the nanoparticle Ni3C as the cocatalyst, which is combined with the semiconductor Mn 0.5 Cd 0.5 S and the semiconductor CaTiO3 to form an S-type heterojunction to prepare the Mn 0.5 Cd 0.5 S / CaTiO3 / Ni3C composite photocatalyst, in which the Mn 0.5 Cd 0.5 S, CaTiO3 and Ni3C have a mass ratio of 1:0.01-0.2:0.01-0.1; XRD has diffraction peaks at 26.67°, 44.17° and 52.18°; XPS has binding energies at 640.55 eV, 651.98 eV, 404.61 eV, 411.34 eV, 161.26 eV, 162.35 eV, 346.39 eV, 350.30 eV, 458.18 eV, 464.10 eV, 529.47 eV, 531.21 eV, 852.32 eV, 855.19 eV, 860.09 eV, 872.71 eV, 878.54 eV, 284.69 eV, 286.13 eV and 288.26 eV; the Mn 0.5 Cd 0.5 S and Ni3C are both in a nanoparticle structure, and the CaTiO3 is in a nanosheet structure; The Mn 0.5 Cd 0.5 The specific preparation steps of the S / CaTiO3 / Ni3C material are as follows: 1) Dissolve calcium nitrate, tetrabutyl titanate and sodium hydroxide in deionized water, and carry out hydrothermal reaction at 160-250℃, and obtain CaTiO3 nanosheet after treatment; 2) Dissolve nickel acetate in oleylamine, and carry out hydrothermal reflux reaction at 160-250℃ under nitrogen atmosphere, and obtain Ni3C nanoparticle after treatment. 3) dispersing manganese acetate, cadmium acetate, thioacetamide and CaTiO3 nanosheets obtained in step 1) in deionized water, after vigorous stirring, the obtained mixed solution is subjected to hydrothermal reaction at 160-250°C, and after treatment, Mn 0.5 Cd 0.5 S / CaTiO3 composite is obtained; 4) dispersing the Ni3C nanoparticles obtained in step 2) and the Mn 0.5 Cd 0.5 S / CaTiO3 composite in an alkaline aqueous solution, performing ultrasonic and stirring treatment, and obtaining Mn 0.5 Cd 0.5 S / CaTiO3 / Ni3C ternary composite photocatalyst.
2. Use according to claim 1, characterized in that: The molar ratio of calcium nitrate to tetrabutyl titanate in step 1) is 1:
1.
3. Use according to claim 1, characterized in that: The molar ratio of nickel acetate to oleylamine in step 2) is 1:
20.
4. Use according to claim 1, characterized in that: The molar ratio of manganese acetate, cadmium acetate and thioacetamide in step 3) is 1:1:2; the obtained Mn 0.5 Cd 0.5 Mn in S / CaTiO3 composite 0.5 Cd 0.5 The mass ratio of S and CaTiO3 is 1:0.01-0.
2.
5. The use according to claim 1, characterized in that: Mn in step 4) 0.5 Cd 0.5 S / CaTiO3 / Ni3C ternary composite photocatalyst nanoparticles cocatalyst Ni3C is loaded on semiconductor Mn 0.5 Cd 0.5 S and semiconductor CaTiO3 form S-type heterojunction.
6. Use according to claim 1, characterized in that: The operation conditions of the photocatalytic nitrogen fixation process are as follows: light source: 300W xenon lamp; amount of catalyst: 0.02g; amount of deionized water: 90mL; amount of methanol: 10mL; flow rate of N2: 20mL / min.