Co 0.2 Cd 0.8 S / CaTiO3 / NiS x Material preparation methods and their applications in photocatalytic nitrogen fixation

Abstract

This invention discloses a Co 0.2 Cd 0.8 This paper describes the preparation method of S / CaTiO3 / NiSx materials and their application in photocatalytic nitrogen fixation, belonging to the field of photocatalytic materials technology. Firstly, an S-type heterostructure Co was prepared using an ultrasonic method. 0.2 Cd 0.8 S / CaTiO3 composite, then using ultrasound to bond metalloid NiS x Nanoparticle co-catalysts and Co 0.2 Cd 0.8 S / CaTiO3 complex forms Co 0.2 Cd 0.8 S / CaTiO3 / NiS x Ternary composite photocatalyst. The semiconductor Co in this invention... 0.2 Cd 0.8 S and semiconductor CaTiO3 first form an S-type heterostructure, which not only accelerates the directional movement and separation of photogenerated electrons and holes, but also maintains the strong redox capability of photogenerated charge carriers; in addition, NiS is loaded onto the S-type heterostructure. x co-catalyst, NiS x Nanoparticle co-catalysts, acting as electron-capturing centers, can not only provide more reactive sites but also further improve charge separation efficiency.

Description

Technical Field

[0001] This invention belongs to the field of composite photocatalytic materials technology, specifically relating to a Co 0.2 Cd 0.8 Preparation method of S / CaTiO3 / NiSx material and its application in photocatalytic nitrogen fixation. Background Technology

[0002] In today's society, energy shortages and environmental pollution remain major problems facing humanity. In recent years, energy sources have primarily relied on fossil fuels or coal. Due to the irreversible nature of production and the severe environmental damage they cause, scientists are dedicated to finding a clean, renewable energy source to replace fossil fuels and address global energy depletion and environmental pollution. Ammonia, as one of the most common nitrogen-containing compounds, is an indispensable precursor in the production of fertilizers, synthetic fibers, and pharmaceuticals, and is widely used in agriculture, medicine, and textiles. Because liquid ammonia has an energy density almost twice that of liquid hydrogen, and can be liquefied at -10°C under low pressure, its safety and minimal energy loss make it easy to store and transport. It is considered an ideal hydrogen storage intermediate and zero-carbon fuel, capable of meeting the growing global population and economic demands. Currently, ammonia production mainly relies on the traditional high-temperature, high-pressure (400-500°C, 150-250 atm) Haber-Bosch process, which requires stringent reaction conditions and sophisticated equipment. Energy consumption accounts for approximately 1%-2% of humanity's annual energy consumption, while releasing approximately 300 million tons of CO2, exacerbating resource waste and severe environmental pollution. Therefore, designing green and sustainable ammonia synthesis pathways using renewable energy sources has become crucial. Nitrogen, as a major component of air with a volume fraction as high as 78%, has attracted widespread attention due to its reduction to ammonia, known as the nitrogen reduction reaction.

[0003] To date, researchers have developed and designed many highly active nitrogen-fixing photocatalysts, including oxides, sulfides, nitrides, and carbides. x Cd 1-x S solid solutions, as metal sulfides, have shown outstanding performance in many fields such as photocatalytic nitrogen fixation, dye-sensitized solar cells, and supercapacitors, and have attracted widespread attention from researchers in recent years. x Cd 1-x Besides its advantages of narrow band gap and high flat band potential, sulfur (S) can also effectively transfer charge through intermediate sulfur atoms bonded to other metals at the interface. Although Co... x Cd 1-x S possesses a suitable band gap and a high conduction band position; however, the rapid recombination of electron and hole pairs during the photocatalytic reaction severely affects the performance of Co. x Cd 1-x S photocatalytic activity. To improve Co x Cd1-x To enhance the activity of Co photocatalysts, various modification strategies have been proposed, such as heteroatom doping, constructing heterostructures, and supporting catalysts. x Cd 1-x The nitrogen-fixing activity of S. This invention utilizes nanoparticle-shaped NiS. x As a co-catalyst, it was successfully combined with Co 0.2 Cd 0.8 A composite photocatalyst, combining S nanoparticles and CaTiO3 nanocubes to form a heterostructure and co-catalyst support, is applied to photocatalytic nitrogen fixation energy. This invention utilizes the semiconductor Co... 0.2 Cd 0.8 S and semiconductor CaTiO3 first form an S-type heterostructure, which not only accelerates the directional migration and separation of photogenerated electrons and holes, but also maintains the strong redox capability of photogenerated charge carriers; in addition, NiS x Nanoparticle co-catalysts, acting as electron-capturing centers, not only provide more reactive sites but also further enhance charge separation efficiency. Based on these advantages, the Co prepared in this invention... 0.2 Cd 0.8 S / CaTiO3 / NiS x Composite catalysts have shown promising applications in photocatalytic nitrogen fixation energy, but there are currently no related reports. Summary of the Invention

[0004] The purpose of this invention is to provide a Co that is simple to operate and easy to implement. 0.2 Cd 0.8 S / CaTiO3 / NiS x The preparation method of the material and its application in photocatalytic nitrogen fixation, and the Co prepared by this method 0.2 Cd 0.8 S / CaTiO3 / NiS x Composite photocatalysts exhibit good photocatalytic nitrogen fixation activity.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: Co 0.2 Cd 0.8 S / CaTiO3 / NiS x The material is characterized by: the material being composed of NiS nanoparticles. x As a co-catalyst, it is combined with semiconductor Co 0.2 Cd 0.8 A composite photocatalyst was prepared by combining S-type heterostructures formed from S and semiconductor CaTiO3. In this composite photocatalyst, Co... 0.2 Cd 0.8 S, CaTiO3 and NiS xThe mass ratio is 1:0.01-0.2:0.01-0.1; XRD shows diffraction peaks at 25.09°, 26.68°, 28.28°, 36.96°, 44.05°, 48.12°, and 52.2°; XPS shows binding energies at 781.40 eV, 799.20 eV, 404.50 eV, 411.30 eV, 160.80 eV, 162 eV, 346 eV, 349.50 eV, 458 eV, 463.90 eV, 529.40 eV, 531.20 eV, 853.92 eV, 857.03 eV, 862.03 eV, 871.32 eV, 875.46 eV, and 881.27 eV; Co in the composite photocatalyst... 0.2 Cd 0.8 S and NiS x It has a nanoparticle structure, while CaTiO3 has a nanocubic structure.

[0006] The XRD data analysis chart clearly shows pure Co. 0.2 Cd 0.8 S exhibits seven diffraction peaks at 25.09°, 26.68°, 28.28°, 36.96°, 44.05°, 48.12°, and 52.2°, corresponding to the (100), (002), (101), (102), (110), (103), and (112) crystal planes, respectively. Co 0.2 Cd 0.8 The XRD spectrum of S is consistent with previous literature reports, indicating that Co 0.2 Cd 0.8 Sample S was successfully synthesized. Pure CaTiO3 clearly shows distinct diffraction peaks at 23.2°, 33.1°, 38.9°, 47.3°, 51.4°, 59°, 69.3°, and 78.9° in the figure, corresponding to the (101), (121), (022), (040), (123), (042), (242), and (161) crystal planes of the orthorhombic CaTiO3 phase, respectively. These peaks correspond to the standard card (JCPDS no. 22-0153), and no other impurity peaks are observed. NiS x The XRD pattern of NiS exhibits distinct diffraction peaks at 26.56°, 30.09°, 31.51°, 34.68°, 35.31°, 38.48°, 45.94°, 53.52°, and 54.46°, corresponding to the (121), (100), (200), (101), (210), (211), (220), (311), and (044) crystal planes, respectively. xThe XRD spectrum of NiS is consistent with previous reports in related literature, indicating that NiS x The sample was successfully synthesized. 0.2 Cd 0.8 S / CaTiO3 / NiS x Co is present in the composite sample 0.2 Cd 0.8 S diffraction peaks were observed, but CaTiO3 and NiS were not observed in the diffraction pattern. x The diffraction peaks are likely due to the presence of CaTiO3 and NiS. x The content is low or CaTiO3 and NiS x This is caused by the diffraction peaks being too weak.

[0007] XPS Analysis Co 0.2 Cd 0.8 S / CaTiO3 / NiS x The elemental composition of the composite sample can be seen from the spectrum, including Co2P. 1 / 2 and Co 2P 3 / 2 The binding energies are 781.40 eV and 799.20 eV, Cd 3d 5 / 2 and Cd 3d 3 / 2 The binding energies are 404.50 eV and 411.30 eV, S 2p 3 / 2 and S 2p 1 / 2 The binding energies are 160.80 eV and 162 eV, indicating that the sample contains Co, Cd, and S elements. The Ca 2p chromatogram shows... 3 / 2 and Ca 2p 1 / 2 The binding energies are 346 eV and 349.50 eV, Ti 2p 3 / 2 and Ti 2p 1 / 2 The binding energies of Ni and Ti are 458 eV and 463.90 eV, respectively, while those of O are 529.40 eV and 531.20 eV, respectively, indicating that the sample contains Ca, Ti, and O elements. The Ni 2p phase in the spectrum... 3 / 2 and Ni 2p 1 / 2 The binding energies are 857.03 eV and 875.46 eV. XPS spectra revealed that the three-component composite contains Co, Cd, S, Ca, Ti, O, and Ni elements, further confirming the successful preparation of Co. 0.2 Cd 0.8 S / CaTiO3 / NiS x Composite materials.

[0008] SEM analysis of the sample morphology shows that Co 0.2 Cd 0.8 S is composed of irregularly aggregated nanoparticles; CaTiO3 is a nano-hollow cube; and it is related to Co. 0.2 Cd0.8 The morphology of S is similar to that of NiS x It is also composed of nanoparticles that are similar to nanospheres stacked together.

[0009] Co 0.2 Cd 0.8 S / CaTiO3 / NiS x The composite photocatalyst was characterized by XRD and XPS. XRD characterization showed the presence of Co. 0.2 Cd 0.8 The presence of diffraction peaks for S, along with the absence of other impurity peaks, indicates that the prepared sample has high purity; furthermore, due to the presence of CaTiO3 and NiS... x The loading is relatively small, CaTiO3 and NiS x No diffraction peaks were detected. XPS characterization showed that the prepared Co... 0.2 Cd 0.8 S / CaTiO3 / NiS x The composite sample contained Co, Cd, S, Ca, Ti, O, and Ni elements, further confirming the presence of Co in the prepared sample. 0.2 Cd 0.8 S / CaTiO3 / NiS x Co is present in the composite sample 0.2 Cd 0.8 S, CaTiO3 and NiS x exist.

[0010] The preparation method of the composite photocatalyst provided by this invention is as follows:

[0011] Co 0.2 Cd 0.8 S / CaTiO3 / NiS x The method for preparing the material is characterized by comprising the following steps:

[0012] 1) Cobalt acetate, cadmium acetate, and thiourea are dissolved in deionized water. After complete dissolution, ethylenediamine is added. The solution is then subjected to a hydrothermal reaction at 150-200℃ to obtain Co. 0.2 Cd 0.8 S nanoparticles;

[0013] Furthermore, in the above technical solution, the molar ratio of cobalt acetate, cadmium acetate and thiourea is 1:4:10;

[0014] 2) Add calcium nitrate, tetrabutyl titanate, sodium hydroxide, and the Co obtained in step 1) 0.2 Cd 0.8 S-type nanoparticles were dispersed in deionized water, and the solution was subjected to a hydrothermal reaction at 150-200℃ to obtain an S-type heterostructured Co. 0.2 Cd 0.8S / CaTiO3 complex;

[0015] Furthermore, in the above technical solution, the molar ratio of calcium nitrate to tetrabutyl titanate is 1:1; the resulting Co 0.2 Cd 0.8 Co in the S / CaTiO3 complex 0.2 Cd 0.8 The mass ratio of S to CaTiO3 is 1:0.01-0.2;

[0016] 3) Dissolve nickel chloride and thioacetamide in deionized water, and subject the solution to a hydrothermal reaction at 150-200℃ to obtain NiS. x Nanoparticles;

[0017] Furthermore, in the above technical solution, the molar ratio of nickel chloride to thioacetamide is 1:4;

[0018] 4) Take the NiS obtained in step 3) x Nanoparticles and Co obtained in step 2) 0.2 Cd 0.8 The S / CaTiO3 complex was dispersed in an alkaline aqueous solution and subjected to ultrasonic and stirring treatment to obtain Co. 0.2 Cd 0.8 S / CaTiO3 / NiS x Ternary composite photocatalyst;

[0019] Furthermore, in the above technical solution, the obtained Co 0.2 Cd 0.8 S / CaTiO3 / NiS x NiS nanoparticles in ternary composite photocatalysts x Cocatalyst supported on semiconductor Co 0.2 Cd 0.8 On an S-type heterostructure formed by S and semiconductor CaTiO3.

[0020] Co prepared according to the above method 0.2 Cd 0.8 S / CaTiO3 / NiS x Photocatalytic nitrogen fixation experiment using a ternary composite photocatalyst:

[0021] Operating conditions: Light source: 300W xenon lamp; Catalyst amount: 0.02g; Deionized water amount: 90mL; Methanol amount: 10mL; N2 flow rate: 20mL / min. Pure Co 0.2 Cd 0.8 The photocatalytic nitrogen fixation rate of S is 82.21 µmol g. -1 h -1 And Co 0.2 Cd0.8 S / CaTiO3 / NiS x The photocatalytic nitrogen fixation rate of the composite photocatalyst is 1688.96 µmol g. -1 h -1 It exhibits significantly enhanced photocatalytic nitrogen fixation performance.

[0022] The present invention has the following beneficial effects: the Co prepared by the present invention 0.2 Cd 0.8 S / CaTiO3 / NiS x Semiconductor Co in ternary composite photocatalysts 0.2 Cd 0.8 S and semiconductor CaTiO3 first form an S-shaped heterostructure, which not only accelerates the directional movement and separation of photogenerated electrons and holes, but also maintains the strong redox capability of photogenerated charge carriers; in addition, NiS is loaded on the S-shaped heterostructure. x co-catalyst, NiS x Nanoparticle co-catalysts, acting as electron-trapping centers, not only provide more reactive sites but also further improve charge separation efficiency, thereby enabling the final preparation of Co... 0.2 Cd 0.8 S / CaTiO3 / NiS x The photocatalytic nitrogen fixation performance of ternary composite photocatalysts has been greatly improved. Attached Figure Description

[0023] Figure 1 Co prepared in Example 1 0.2 Cd 0.8 S, CaTiO3, NiS x and Co 0.2 Cd 0.8 S / CaTiO3 / NiS x XRD patterns;

[0024] Figure 2 The middle ah is the Co prepared in Example 1. 0.2 Cd 0.8 S / CaTiO3 / NiS x XPS plot;

[0025] Figure 3 The ac in the middle is the Co prepared in Example 1. 0.2 Cd 0.8 S, CaTiO3 and NiS x SEM image;

[0026] Figure 4 Co prepared in Example 1 0.2 Cd 0.8 S, Co0.2 Cd 0.8 S / CaTiO3, Co 0.2 Cd 0.8 S / CaTiO3 / NiS x The effect of photocatalytic nitrogen fixation. Detailed Implementation

[0027] The following examples further illustrate the above-described content of the present invention, but it should not be construed as limiting the scope of the subject matter of the present invention to the following examples. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention. Example 1

[0028] 1) Co 0.2 Cd 0.8 Preparation of S nanoparticles: 0.5 mmol of Co(CH3COO)2·4H2O, 2 mmol of Cd(CH3COO)2·2H2O, and 5 mmol of thiourea were weighed and dissolved in 25 mL of deionized water. After complete dissolution, 25 mL of ethylenediamine was slowly added to the solution, and the mixture was stirred thoroughly for 1 h. The solution was then subjected to a hydrothermal reaction at 150 °C for 12 h. After the reaction was completed and cooled to room temperature, the mixture was filtered. The sample was washed three times each with deionized water and anhydrous ethanol. The collected solid sample was transferred to a vacuum drying oven and dried at 60 °C for 12 h to obtain Co. 0.2 Cd 0.8 S nanoparticles.

[0029] 2) Co 0.2 Cd 0.8 Preparation of S / CaTiO3 composite sample: 0.08 mmol of Ca(NO3)2·4H2O, 0.08 mmol of tetrabutyl titanate, and 0.8 g of NaOH were weighed and dissolved in 30 mL of deionized water. After complete dissolution, 1 g of Co obtained in step 1) was added. 0.2 Cd 0.8 S nanoparticles were stirred vigorously for 1 hour, and the resulting solution was transferred to a hydrothermal reactor and subjected to a hydrothermal reaction at 150°C for 24 hours. After the reaction was completed and the mixture was cooled to room temperature, it was filtered and washed three times each with deionized water and anhydrous ethanol. The collected solid sample was then transferred to a vacuum drying oven and dried at 60°C for 12 hours to obtain Co. 0.2 Cd 0.8 S / CaTiO3 complex.

[0030] 3) NiS xPreparation of nanoparticles: 1 mmol NiCl2·6H2O and 4 mmol CH3CSNH2 were weighed and dissolved in 20 mL deionized water. The mixture was stirred thoroughly for 1 h. The solution was then subjected to a hydrothermal reaction at 150 °C for 12 h. After the reaction was completed and cooled to room temperature, the mixture was filtered. The sample was washed three times each with deionized water and anhydrous ethanol. The collected solid sample was transferred to a vacuum drying oven and dried at 60 °C for 12 h to obtain NiS2. x Nanoparticles.

[0031] 4) Co 0.2 Cd 0.8 S / CaTiO3 / NiS x Preparation of composite sample: Take 0.1g of Co obtained in step 2). 0.2 Cd 0.8 S / CaTiO3 complex and 1 mg of NiS obtained in step 3) x Nanoparticles were dispersed in 50 mL of dilute NaOH aqueous solution and sonicated for 2 h. The solution was then stirred for another 10 h. The resulting product was washed with deionized water and anhydrous ethanol, and then vacuum dried to obtain Co. 0.2 Cd 0.8 S / CaTiO3 / NiS x Ternary composite photocatalyst.

[0032] from Figure 1 The prepared Co can be clearly seen in the image. 0.2 Cd 0.8 S / CaTiO3 / NiS x Co is present in the composite sample 0.2 Cd 0.8 The diffraction peaks of S and CaTiO3, and the absence of diffraction peaks of other substances, indicate that the prepared Co... 0.2 Cd 0.8 The S and CaTiO3 samples had relatively high purity. However, NiS was not observed in the diffraction patterns. x The diffraction peaks are likely due to NiS x The content is low or NiS x The diffraction peaks of the nanoparticles are too weak, leading to this. (NiS) x Successful loading of nanoparticles can be further confirmed by XPS.

[0033] from Figure 2 The prepared Co can be clearly seen in the image. 0.2 Cd 0.8 S / CaTiO3 / NiS x The composite sample contained Co, Cd, S, Ca, Ti, O, and Ni elements, further confirming the prepared Co... 0.2 Cd 0.8S / CaTiO3 / NiS x Co is present in the composite sample 0.2 Cd 0.8 S, CaTiO3 and NiS x exist.

[0034] from Figure 4 It can be seen from the prepared ternary system Co 0.2 Cd 0.8 S / CaTiO3 / NiS x The photocatalytic nitrogen fixation performance of the composite sample was significantly higher than that of Co. 0.2 Cd 0.8 S and Co 0.2 Cd 0.8 S / CaTiO3 samples illustrate the construction of the S heterostructure and the role of NiS as a cocatalyst. x The introduction of Co effectively enhanced Co 0.2 Cd 0.8 Photocatalytic nitrogen fixation performance of sample S. Example 2

[0035] 1) Co 0.2 Cd 0.8 Preparation of S nanoparticles: 0.5 mmol of Co(CH3COO)2·4H2O, 2 mmol of Cd(CH3COO)2·2H2O, and 5 mmol of thiourea were weighed and dissolved in 25 mL of deionized water. After complete dissolution, 25 mL of ethylenediamine was slowly added to the solution, and the mixture was stirred thoroughly for 1 h. The solution was then subjected to a hydrothermal reaction at 180 °C for 12 h. After the reaction was completed and cooled to room temperature, the mixture was filtered. The sample was washed three times each with deionized water and anhydrous ethanol. The collected solid sample was transferred to a vacuum drying oven and dried at 60 °C for 12 h to obtain Co. 0.2 Cd 0.8 S nanoparticles.

[0036] 2) Co 0.2 Cd 0.8 Preparation of S / CaTiO3 composite sample: 0.08 mmol of Ca(NO3)2·4H2O, 0.08 mmol of tetrabutyl titanate, and 0.8 g of NaOH were weighed and dissolved in 30 mL of deionized water. After complete dissolution, 0.1 g of Co obtained in step 1) was added. 0.2 Cd 0.8 S nanoparticles were stirred vigorously for 1 hour, and the resulting solution was transferred to a hydrothermal reactor and subjected to a hydrothermal reaction at 180°C for 24 hours. After the reaction was completed and the mixture was cooled to room temperature, it was filtered and washed three times each with deionized water and anhydrous ethanol. The collected solid sample was then transferred to a vacuum drying oven and dried at 60°C for 12 hours to obtain Co. 0.2 Cd 0.8S / CaTiO3 complex.

[0037] 3) NiS x Preparation of nanoparticles: 1 mmol NiCl2·6H2O and 4 mmol CH3CSNH2 were weighed and dissolved in 20 mL deionized water. The mixture was stirred thoroughly for 1 h. The solution was then subjected to a hydrothermal reaction at 180 °C for 12 h. After the reaction was completed and cooled to room temperature, the mixture was filtered. The sample was washed three times each with deionized water and anhydrous ethanol. The collected solid sample was transferred to a vacuum drying oven and dried at 60 °C for 12 h to obtain NiS. x Nanoparticles.

[0038] 4) Co 0.2 Cd 0.8 S / CaTiO3 / NiS x Preparation of composite sample: Take 0.1g of Co obtained in step 2). 0.2 Cd 0.8 S / CaTiO3 composite and 0.01g of NiS obtained in step 3) x Nanoparticles were dispersed in 50 mL of dilute NaOH aqueous solution and sonicated for 2 h. The solution was then stirred for another 10 h. The resulting product was washed with deionized water and anhydrous ethanol, and then vacuum dried to obtain Co. 0.2 Cd 0.8 S / CaTiO3 / NiS x Ternary composite photocatalyst. Example 3

[0039] 1) Co 0.2 Cd 0.8 Preparation of S nanoparticles: 0.5 mmol of Co(CH3COO)2·4H2O, 2 mmol of Cd(CH3COO)2·2H2O, and 5 mmol of thiourea were weighed and dissolved in 25 mL of deionized water. After complete dissolution, 25 mL of ethylenediamine was slowly added to the solution, and the mixture was stirred thoroughly for 1 h. The solution was then subjected to a hydrothermal reaction at 200 °C for 12 h. After the reaction was completed and cooled to room temperature, the mixture was filtered. The sample was washed three times each with deionized water and anhydrous ethanol. The collected solid sample was transferred to a vacuum drying oven and dried at 60 °C for 12 h to obtain Co. 0.2 Cd 0.8 S nanoparticles.

[0040] 2) Co 0.2 Cd 0.8 Preparation of S / CaTiO3 composite sample: 0.08 mmol of Ca(NO3)2·4H2O, 0.08 mmol of tetrabutyl titanate, and 0.8 g of NaOH were weighed and dissolved in 30 mL of deionized water. After complete dissolution, 0.05 g of Co obtained in step 1) was added. 0.2Cd 0.8 S nanoparticles were stirred vigorously for 1 hour, and the resulting solution was transferred to a hydrothermal reactor and subjected to a hydrothermal reaction at 200°C for 24 hours. After the reaction was completed and the mixture was cooled to room temperature, it was filtered and washed three times each with deionized water and anhydrous ethanol. The collected solid sample was then transferred to a vacuum drying oven and dried at 60°C for 12 hours to obtain Co. 0.2 Cd 0.8 S / CaTiO3 complex.

[0041] 3) NiS x Preparation of nanoparticles: 1 mmol NiCl2·6H2O and 4 mmol CH3CSNH2 were weighed and dissolved in 20 mL deionized water. The mixture was stirred thoroughly for 1 h. The solution was then subjected to a hydrothermal reaction at 200 °C for 12 h. After the reaction was completed and cooled to room temperature, the mixture was filtered. The sample was washed three times each with deionized water and anhydrous ethanol. The collected solid sample was transferred to a vacuum drying oven and dried at 60 °C for 12 h to obtain NiS. x Nanoparticles.

[0042] 4) Co 0.2 Cd 0.8 S / CaTiO3 / NiS x Preparation of composite sample: Take 0.1g of Co obtained in step 2). 0.2 Cd 0.8 S / CaTiO3 composite and 0.02 g of NiS obtained in step 3) x Nanoparticles were dispersed in 50 mL of dilute NaOH aqueous solution and sonicated for 2 h. The solution was then stirred for another 10 h. The resulting product was washed with deionized water and anhydrous ethanol, and then vacuum dried to obtain Co. 0.2 Cd 0.8 S / CaTiO3 / NiS x Ternary composite photocatalyst.

[0043] Example 4

[0044] Photocatalytic nitrogen fixation experiment:

[0045] Operating conditions: Light source: 300W xenon lamp; Catalyst amount: 0.02g; Deionized water amount: 90mL; Methanol amount: 10mL. From Figure 4 From this, we can see that pure Co 0.2 Cd 0.8 The photocatalytic nitrogen fixation rate of S is 82.21 µmol g. -1 h -1 The Co prepared using Example 1 0.2 Cd 0.8 S / CaTiO3 / NiS xThe photocatalytic nitrogen fixation rate of the ternary composite photocatalyst reaches as high as 1688.96 µmol / g. -1 h -1 It exhibits significantly enhanced photocatalytic nitrogen fixation performance. Combined with... Figure 1-4 The results demonstrate that Co with enhanced photocatalytic nitrogen fixation performance has been successfully prepared. 0.2 Cd 0.8 S / CaTiO3 / NiS x Ternary composite photocatalyst.

[0046] Co prepared using Examples 2-3 0.2 Cd 0.8 S / CaTiO3 / NiS x Ternary composite photocatalysts can achieve similar photocatalytic nitrogen fixation effects.

[0047] 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. Co 0.2 Cd 0.8 S / CaTiO3 / NiS x The material is characterized by: This material uses nanoparticles of NiS x As a co-catalyst, it is combined with semiconductor Co 0.2 Cd 0.8 A composite photocatalyst was prepared by combining S-type heterostructures formed from S and semiconductor CaTiO3. In this composite photocatalyst, Co... 0.2 Cd 0.8 S, CaTiO3 and NiS x The mass ratio is 1:0.01-0.2:0.01-0.1; XRD shows diffraction peaks at 25.09°, 26.68°, 28.28°, 36.96°, 44.05°, 48.12°, and 52.2°; XPS shows binding energies at 781.40 eV, 799.20 eV, 404.50 eV, 411.30 eV, 160.80 eV, 162 eV, 346 eV, 349.50 eV, 458 eV, 463.90 eV, 529.40 eV, 531.20 eV, 853.92 eV, 857.03 eV, 862.03 eV, 871.32 eV, 875.46 eV, and 881.27 eV; Co in the composite photocatalyst... 0.2 Cd 0.8 S and NiS x It has a nanoparticle structure, while CaTiO3 has a nanocubic structure.

2. A Co as described in claim 1 0.2 Cd 0.8 S / CaTiO3 / NiS x The method for preparing the material is characterized by The specific steps are as follows: 1) Cobalt acetate, cadmium acetate, and thiourea are dissolved in deionized water. After complete dissolution, ethylenediamine is added. The solution is then subjected to a hydrothermal reaction at 150-200℃ to obtain Co. 0.2 Cd 0.8 S nanoparticles; 2) Add calcium nitrate, tetrabutyl titanate, sodium hydroxide, and the Co obtained in step 1) 0.2 Cd 0.8 S-type nanoparticles were dispersed in deionized water, and the solution was subjected to a hydrothermal reaction at 150-200℃ to obtain an S-type heterostructured Co. 0.2 Cd 0.8 S / CaTiO3 complex; 3) Dissolve nickel chloride and thioacetamide in deionized water, and subject the solution to a hydrothermal reaction at 150-200℃ to obtain NiS. x Nanoparticles; 4) Take the NiS obtained in step 3) x Nanoparticles and Co obtained in step 2) 0.2 Cd 0.8 The S / CaTiO3 complex was dispersed in an alkaline aqueous solution and subjected to ultrasonic and stirring treatment to obtain Co. 0.2 Cd 0.8 S / CaTiO3 / NiS x Ternary composite photocatalyst.

3. The Co according to claim 2 0.2 Cd 0.8 S / CaTiO3 / NiS x The method for preparing the material is characterized by: In step 1), the molar ratio of cobalt acetate, cadmium acetate, and thiourea is 1:4:

10.

4. The Co according to claim 2 0.2 Cd 0.8 S / CaTiO3 / NiS x The method for preparing the material is characterized by: In step 2), the molar ratio of calcium nitrate to tetrabutyl titanate is 1:1; the resulting Co 0.2 Cd 0.8 Co in the S / CaTiO3 complex 0.2 Cd 0.8 The mass ratio of S to CaTiO3 is 1:0.01-0.

2.

5. The Co according to claim 2 0.2 Cd 0.8 S / CaTiO3 / NiS x The method for preparing the material is characterized by: The molar ratio of nickel chloride to thioacetamide is 1:

4.

6. The Co as described in claim 1 0.2 Cd 0.8 S / CaTiO3 / NiS x Application of materials in photocatalytic nitrogen fixation.

7. The application according to claim 6, characterized in that: Photogenerated electrons in the conduction band of semiconductor CaTiO3 interact with Co through band bending and the built-in electric field. 0.2 Cd 0.8 S-valence band hole recombination, while remaining in semiconductor Co 0.2 Cd 0.8 Photogenerated electrons in the S-band are transferred to the cocatalyst NiS. x The surface allows more photogenerated electrons with strong reducing properties to participate in the reduction reaction, reducing N2 to NH4. + .

8. The application according to claim 6, characterized in that: Operating conditions were as follows: Light source: 300W xenon lamp; Catalyst amount: 0.02g; Deionized water amount: 90mL; Methanol amount: 10mL; N2 flow rate: 20mL / min; Co 0.2 Cd 0.8 S / CaTiO3 / NiS x The photocatalytic nitrogen fixation rate of the ternary composite photocatalyst is 1688.96 µmol g. -1 h -1 .

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