Ce-FeIn2S4-MoSe2 heterojunction photocatalyst and preparation method thereof

Abstract

The invention discloses a Ce-FeIn2S4-MoSe2 heterojunction photocatalyst and a preparation method of the Ce-FeIn2S4-MoSe2 heterojunction photocatalyst. The preparation method specifically comprises the following steps: firstly, preparing Ce-FeIn2S4 through a solvothermal reaction; then, the prepared Ce-FeIn2S4 is mixed with a precursor of MoSe2, and the Ce-FeIn2S4-MoSe2 heterojunction photocatalyst is prepared through a solvothermal reaction. According to the photocatalyst heterogeneous material prepared by the method disclosed by the invention, an atomic-scale heterogeneous interface is established through an S-Mo bond, and chemical bond mediated heterogeneous coupling not only realizes strong interface bonding of FeIn2S4 and MoSe2 heterogeneous materials, but also establishes a cross-interface charge transfer channel, so that a carrier migration barrier is remarkably reduced, spatial separation of photo-induced electron-hole pairs is promoted, and the photocatalytic performance of the photocatalyst is improved. Therefore, the light quantum efficiency and the photocatalytic activity of the material system are synergistically improved.

Description

Technical Field

[0001] The present invention relates to a Ce-FeIn 2 S 4 -MoSe 2 heterojunction photocatalyst, and also relates to a preparation method of the above photocatalyst. Background Art

[0002] Based on the photocatalytic technology of semiconductor heterojunctions, due to its dual application prospects in the fields of solar energy conversion and environmental remediation, it has become a hot research direction of new energy materials. However, traditional wide-bandgap semiconductors (such as TiO 2 , ZnO, etc.) are severely restricted in their actual application efficiency due to insufficient visible light absorption efficiency. In recent years, iron-based chalcogenides FeIn 2 S 4 exhibit excellent visible light capture ability due to their narrow bandgap characteristics of 1.5 - 2.0 eV, and at the same time have high chemical stability and environmental friendliness, and are regarded as a new generation of photocatalytic candidate materials. However, this material has an inherent defect of rapid recombination of photo-generated carriers, resulting in a low quantum efficiency. Transition metal disulfide MoSe 2 due to its unique layered structure and adjustable electronic energy band, and has a suitable bandgap. Its energy band edge position with FeIn 2 S 4 can form a staggered energy band structure, and theoretically can achieve spatial separation of photo-generated electron-hole pairs. However, if FeIn 2 S 4 is directly compounded with MoSe 2 there will be problems such as insufficient nano-interface contact, poor bonding degree between heterogeneous materials, and too high interlayer charge transfer barrier, and these problems will seriously weaken the synergistic catalytic effect of the heterojunction. Summary of the Invention

[0003] Object of the Invention: The object of the present invention is to provide a Ce-FeIn 2 S 4 -MoSe 2 heterojunction photocatalyst. Another object of the present invention is to provide a preparation method of the above photocatalyst. The Ce-FeIn 2 S 4 -MoSe 2 heterojunction photocatalyst prepared by this method has good photocatalytic activity.

[0004] Technical Solution: The preparation method of the Ce-FeIn 2 S 4 -MoSe 2 heterojunction photocatalyst described in the present invention is specifically as follows: First, prepare Ce-FeIn 2 S4 ; Then, the prepared Ce-FeIn 2 S 4 is mixed with the precursor of MoSe 2 , and a Ce-FeIn 2 S 4 -MoSe 2 heterojunction photocatalyst is obtained through a solvothermal reaction.

[0005] Among them, Ce-FeIn 2 S 4 is specifically prepared by the following method: Calculated according to the stoichiometric ratio of iron, indium, and sulfur, corresponding molar ratios of iron salt, indium salt, and sulfur source are added to deionized water and mixed evenly to obtain solution A; Cerium salt is added to ethylene glycol and stirred evenly to form solution B; Solution B is added to solution A, and a solvothermal reaction is carried out. After the reaction, the product is washed and dried to obtain Ce-FeIn 2 S 4 .

[0006] Among them, the iron salt is ferric chloride hexahydrate; the indium salt is indium(III) chloride tetrahydrate; the sulfur source is thiourea or thioacetamide; the cerium salt is cerium(III) chloride heptahydrate or cerium(III) nitrate hexahydrate.

[0007] Among them, the molar ratio of the iron salt, indium salt, sulfur source, and cerium salt is 1:2:4 - 8:0.06 - 0.18.

[0008] Among them, the reaction temperature is 100 - 160 °C, and the reaction time is 10 - 16 h.

[0009] Among them, the specific process of mixing the precursor of Ce-FeIn 2 S 4 with MoSe 2 to prepare Ce-FeIn 2 S 4 -MoSe 2 is as follows: Sodium molybdate dihydrate, Se powder, sodium borohydride, and Ce-FeIn 2 S 4 are added to deionized water to obtain a mixed solution; The mixed solution is placed for reaction at a high temperature. After the reaction, the product is washed and dried to obtain a Ce-FeIn 2 S 4 -MoSe 2 photocatalyst.

[0010] Among them, the molybdenum salt is sodium molybdate dihydrate.

[0011] Among them, the molar ratio of the molybdenum salt, Se powder, sodium borohydride, and Ce-FeIn 2 S 4The molar ratio is 1:2:5 to 10:4 to 14.

[0012] Among them, the reaction temperature is 120 to 200 °C, and the reaction time is 12 to 18 h.

[0013] The Ce-FeIn 2 S 4 -MoSe 2 heterojunction photocatalyst. In the photocatalyst, Ce is doped in the main metal site lattice of FeIn 2 S 4 matrix, and FeIn 2 S 4 and MoSe 2 form an atomic-level heterojunction interface through a covalent bond (S-Mo bond).

[0014] In the present invention, a hydrothermal lattice substitution method is first used to introduce Ce doping in the FeIn 2 S 4 matrix to replace the main metal site of FeIn 2 S 4 matrix, inducing the formation of S coordination defects to form a highly active surface; this defect-state highly active surface undergoes a directional reaction with the MoSe 2 precursor under solvothermal conditions to form an S-Mo bond chemical bridge, thereby establishing an atomic-level heterojunction interface. This chemical bond-mediated heterocoupling mechanism not only realizes the strong interfacial binding of FeIn 2 S 4 and MoSe 2 heterogeneous materials, but more importantly, it establishes an interfacial charge transfer channel, significantly reducing the carrier migration barrier, promoting the spatial separation of photo-generated electron-hole pairs, and thus synergistically enhancing the light quantum efficiency and photocatalytic activity of the catalytic material. In addition, the doped Ce in the heterojunction system can also enrich active reaction free radicals to synergistically promote the improvement of the photocatalytic activity of the catalytic material.

[0015] Beneficial effects: Compared with the prior art, the present invention has the following remarkable advantages: (1) The method of the present invention obtains rich S-Mo covalent bonds through Ce doping, thereby realizing FeIn 2 S 4 and MoSe 2Strong interfacial bonding of heterogeneous materials. The heterogeneous materials are bonded by S-Mo bonds to achieve atomic-level coupling at the heterogeneous interface, thereby establishing a directional charge transfer channel between the heterojunctions, which can effectively inhibit the recombination of electrons and holes, resulting in a significant improvement in the optical quantum efficiency. (2) The heterojunction photocatalyst prepared by the method of the present invention exhibits excellent broadband visible light response characteristics and has high practical value and application prospects in the field of environmental governance. (3) The method of the present invention has simple process, mild reaction conditions, no pollution to the environment, and is easy to industrialize. Description of the Drawings

[0016] Figure 1 XRD characterization diagrams of the Ce-FeIn 2 S 4 -MoSe 2 prepared in Example 3 and the FeIn 2 S 4 / MoSe 2 photocatalyst;

[0017] Figure 2 XRD characterization diagrams of the Ce-FeIn 2 S 4 -MoSe 2 prepared in Example 3 and the FeIn 2 S 4 / MoSe 2 high-resolution Mo 3d XPS characterization diagrams of the photocatalyst;

[0018] Figure 3 XRD characterization diagrams of the Ce-FeIn 2 S 4 -MoSe 2 prepared in Example 3 and the FeIn 2 S 4 / MoSe 2 photocurrent response diagrams of the photocatalyst;

[0019] Figure 4 Optical absorption performance diagrams of the Ce-FeIn 2 S 4 -MoSe 2 prepared in Example 3;

[0020] Figure 5 Optical absorption performance diagrams of the Ce-FeIn 2 S 4 -MoSe 2 prepared in Example 3, Ce-FeIn 2 S 4 prepared in Example 3 and the FeIn 2 S 4 / MoSe2 Comparison chart of photocatalytic activities of photocatalysts Specific implementation mode

[0021] Example 1

[0022] Ce-FeIn of the present invention 2 S 4 -MoSe 2 Preparation method of heterojunction photocatalyst, specifically including the following steps:

[0023] (1) Prepare Ce-FeIn 2 S 4 : Add 1.5 mmol of ferric chloride hexahydrate, 3.0 mmol of indium trichloride tetrahydrate and 10 mmol of thiourea to 50 mL of deionized water and mix evenly to obtain solution A; add 0.09 mmol of cerium trichloride heptahydrate to 30 mL of ethylene glycol and stir evenly to form solution B; add solution B to solution A and mix evenly, transfer the mixed solution into a reaction kettle, and carry out hydrothermal reaction at 120 °C for 16 h. After the reaction, the obtained product is washed and dried to obtain Ce-FeIn 2 S 4 photocatalyst;

[0024] (2) Disperse 0.3 mmol of sodium molybdate dihydrate, 0.6 mmol of Se powder, 1.5 mmol of sodium borohydride and 1.2 mmol of Ce-FeIn 2 S 4 in 65 mL of deionized water, stir for 50 minutes to obtain a mixed solution; transfer the mixed solution into a reaction kettle, and carry out hydrothermal reaction at 200 °C for 18 h. After the reaction, the obtained product is washed and dried to obtain Ce-FeIn 2 S 4 -MoSe 2 photocatalyst.

[0025] Example 2

[0026] Ce-FeIn of the present invention 2 S 4 -MoSe 2 Preparation method of heterojunction photocatalyst, specifically including the following steps:

[0027] (1) Prepare Ce-FeIn 2 S 4: Add 1.5 mmol of ferric chloride hexahydrate, 3.0 mmol of indium trichloride tetrahydrate, and 10 mmol of thiourea to 50 mL of deionized water and mix well to obtain solution A; add 0.12 mmol of cerium trichloride heptahydrate to 30 mL of ethylene glycol, stir evenly to form solution B; add solution B to solution A and mix well. Transfer the mixed solution into a reaction kettle and carry out a hydrothermal reaction at 140 °C for 16 h. The product obtained after the reaction is washed and dried to obtain Ce-FeIn 2 S 4 photocatalyst;

[0028] (2) Disperse 0.3 mmol of sodium molybdate dihydrate, 0.6 mmol of Se powder, 1.5 mmol of sodium borohydride, and 1.8 mmol of Ce-FeIn 2 S 4 in 65 mL of deionized water and stir for 50 minutes to obtain a mixed solution; transfer the mixed solution into a reaction kettle and carry out a hydrothermal reaction at 200 °C for 18 h. The product obtained after the reaction is washed and dried to obtain Ce-FeIn 2 S 4 -MoSe 2 photocatalyst.

[0029] Example 3

[0030] The preparation method of the Ce-FeIn 2 S 4 -MoSe 2 heterojunction photocatalyst of the present invention specifically includes the following steps:

[0031] (1) Prepare Ce-FeIn 2 S 4 by hydrothermal method: Add 1.5 mmol of ferric chloride hexahydrate, 3.0 mmol of indium trichloride tetrahydrate, and 10 mmol of thiourea to 50 mL of deionized water and mix well to obtain solution A; add 0.15 mmol of cerium trichloride heptahydrate to 30 mL of ethylene glycol, stir evenly to form solution B; add solution B to solution A and mix well. Transfer the mixed solution into a reaction kettle and carry out a hydrothermal reaction at 160 °C for 16 h. The product obtained after the reaction is washed and dried to obtain Ce-FeIn 2 S 4 photocatalyst;

[0032] (2) Disperse 0.3 mmol of sodium molybdate dihydrate, 0.6 mmol of Se powder, 1.5 mmol of sodium borohydride, and 2.4 mmol of Ce-FeIn 2 S 4Dispersed in 65 mL of deionized water and stirred for 50 minutes to obtain a mixed solution; the mixed solution was transferred into a reaction kettle and subjected to hydrothermal reaction at 200 °C for 18 h. The product obtained after the reaction was washed and dried to obtain Ce-FeIn 2 S 4 -MoSe 2 photocatalyst.

[0033] Example 4

[0034] The Ce-FeIn 2 S 4 -MoSe 2 preparation method of the heterojunction photocatalyst specifically comprises the following steps:

[0035] (1) Prepare Ce-FeIn 2 S 4 by hydrothermal method: 1.5 mmol of ferric chloride hexahydrate, 3.0 mmol of indium trichloride tetrahydrate and 10 mmol of thiourea were added to 50 mL of deionized water and mixed evenly to obtain solution A; 0.27 mmol of cerium trichloride heptahydrate was added to 30 mL of ethylene glycol and stirred evenly to form solution B; solution B was added to solution A and mixed evenly. The mixed solution was transferred into a reaction kettle and subjected to hydrothermal reaction at 160 °C for 16 h. The product obtained after the reaction was washed and dried to obtain Ce-FeIn 2 S 4 photocatalyst;

[0036] (2) 0.3 mmol of sodium molybdate dihydrate, 0.6 mmol of Se powder, 1.5 mmol of sodium borohydride and 4.2 mmol of Ce-FeIn 2 S 4 were dispersed in 65 mL of deionized water and stirred for 50 minutes to obtain a mixed solution; the mixed solution was transferred into a reaction kettle and subjected to hydrothermal reaction at 200 °C for 18 h. The product obtained after the reaction was washed and dried to obtain Ce-FeIn 2 S 4 -MoSe 2 photocatalyst.

[0037] Comparative Example 1

[0038] A preparation method of an FeIn 2 S 4 -MoSe 2 heterojunction photocatalyst specifically comprises the following steps:

[0039] (1) Prepare FeIn 2 S 4: 1.5 mmol of iron(III) chloride hexahydrate, 3.0 mmol of indium(III) chloride tetrahydrate and 10 mmol of thiourea were added to 50 mL of deionized water and mixed evenly. The mixed solution was transferred into a reaction kettle and subjected to hydrothermal reaction at 160 °C for 16 h. The product obtained after the reaction was washed and dried to obtain FeIn 2 S 4 photocatalyst;

[0040] (2) 0.3 mmol of sodium molybdate dihydrate, 0.6 mmol of Se powder, 1.5 mmol of sodium borohydride and 2.4 mmol of FeIn 2 S 4 were dispersed in 65 mL of deionized water and stirred for 50 minutes to obtain a mixed solution. The mixed solution was transferred into a reaction kettle and subjected to hydrothermal reaction at 200 °C for 18 h. The product obtained after the reaction was washed and dried to obtain FeIn 2 S 4 / MoSe 2 photocatalyst.

[0041] Comparative Example 2

[0042] A preparation method of a Ce-FeIn 2 S 4 -MoSe 2 heterojunction photocatalyst, which specifically includes the following steps:

[0043] (1) Ce-FeIn was prepared by hydrothermal method 2 S 4 : 1.5 mmol of iron(III) chloride hexahydrate, 3.0 mmol of indium(III) chloride tetrahydrate and 10 mmol of thiourea were added to 50 mL of deionized water and mixed evenly to obtain solution A; 0.15 mmol of cerium(III) chloride heptahydrate was added to 30 mL of ethylene glycol and stirred evenly to form solution B; solution B was added to solution A and mixed evenly. The mixed solution was transferred into a reaction kettle and subjected to hydrothermal reaction at 160 °C for 16 h. The product obtained after the reaction was washed and dried to obtain Ce-FeIn 2 S 4 photocatalyst;

[0044] (2) 0.3 mmol of sodium molybdate dihydrate, 0.6 mmol of Se powder, 1.5 mmol of sodium borohydride and 0.6 mmol of Ce-FeIn 2 S 4 were dispersed in 65 mL of deionized water and stirred for 50 minutes to obtain a mixed solution. The mixed solution was transferred into a reaction kettle and subjected to hydrothermal reaction at 200 °C for 18 h. The product obtained after the reaction was washed and dried to obtain Ce-FeIn 2 S 4 -MoSe 2Photocatalyst.

[0045] Comparative Example 3

[0046] A Ce-FeIn 2 S 4 -MoSe 2 Preparation method of heterojunction photocatalyst, specifically including the following steps:

[0047] (1) Prepare Ce-FeIn 2 S 4 : Add 1.5 mmol of ferric chloride hexahydrate, 3.0 mmol of indium trichloride tetrahydrate, and 10 mmol of thiourea to 50 mL of deionized water and mix evenly to obtain solution A; add 0.15 mmol of cerium trichloride heptahydrate to 30 mL of ethylene glycol, stir evenly to form solution B; add solution B to solution A and mix evenly, transfer the mixed solution into a reaction kettle, and carry out hydrothermal reaction at 160 °C for 16 h. The product obtained after the reaction is washed and dried to obtain Ce-FeIn 2 S 4 photocatalyst;

[0048] (2) Disperse 0.3 mmol of sodium molybdate dihydrate, 0.6 mmol of Se powder, 1.5 mmol of sodium borohydride, and 5.4 mmol of Ce-FeIn 2 S 4 in 65 mL of deionized water, stir for 50 minutes to obtain a mixed solution; transfer the mixed solution into a reaction kettle, and carry out hydrothermal reaction at 200 °C for 18 h. The product obtained after the reaction is washed and dried to obtain Ce-FeIn 2 S 4 -MoSe 2 photocatalyst.

[0049] Comparative Example 4

[0050] A Ce-FeIn 2 S 4 -MoSe 2 Preparation method of heterojunction photocatalyst, specifically including the following steps:

[0051] (1) Prepare Ce-FeIn 2 S 4: Add 1.5 mmol of ferric chloride hexahydrate, 3.0 mmol of indium trichloride tetrahydrate, and 10 mmol of thiourea to 50 mL of deionized water and mix evenly to obtain Solution A; add 0.15 mmol of cerium trichloride heptahydrate to 30 mL of ethylene glycol, stir evenly to form Solution B; add Solution B to Solution A and mix evenly. Transfer the mixed solution to a reaction kettle and carry out a hydrothermal reaction at 160 °C for 16 h. After the reaction, the obtained product is washed and dried to obtain Ce-FeIn 2 S 4 photocatalyst;

[0052] (2) Disperse 0.3 mmol of sodium molybdate dihydrate, 0.6 mmol of Se powder, 1.5 mmol of sodium borohydride, and 2.4 mmol of Ce-FeIn 2 S 4 in 65 mL of deionized water and stir for 50 minutes to obtain a mixed solution; transfer the mixed solution to a reaction kettle and carry out a hydrothermal reaction at 80 °C for 18 h. After the reaction, the obtained product is washed and dried to obtain Ce-FeIn 2 S 4 -MoSe 2 photocatalyst.

[0053] Comparative Example 5

[0054] A preparation method of a Ce-FeIn 2 S 4 -MoSe 2 heterojunction photocatalyst specifically includes the following steps:

[0055] (1) Prepare Ce-FeIn 2 S 4 by hydrothermal method: Add 1.5 mmol of ferric chloride hexahydrate, 3.0 mmol of indium trichloride tetrahydrate, and 10 mmol of thiourea to 50 mL of deionized water and mix evenly to obtain Solution A; add 0.15 mmol of cerium trichloride heptahydrate to 30 mL of ethylene glycol, stir evenly to form Solution B; add Solution B to Solution A and mix evenly. Transfer the mixed solution to a reaction kettle and carry out a hydrothermal reaction at 160 °C for 16 h. After the reaction, the obtained product is washed and dried to obtain Ce-FeIn 2 S 4 photocatalyst;

[0056] (2) Disperse 0.3 mmol of sodium molybdate dihydrate, 0.6 mmol of Se powder, 1.5 mmol of sodium borohydride, and 2.4 mmol of Ce-FeIn 2 S 4Dispersed in 65 mL of deionized water and stirred for 50 minutes to obtain a mixed solution; the mixed solution was transferred to a reaction kettle and subjected to hydrothermal reaction at 250 °C for 18 h. The product obtained after the reaction was washed and dried to obtain Ce-FeIn 2 S 4 -MoSe 2 photocatalyst.

[0057] Figure 1 is the Ce-FeIn prepared in Example 3 2 S 4 -MoSe 2 and the FeIn prepared in Comparative Example 1 2 S 4 / MoSe 2 XRD characterization diagrams of the photocatalysts. In Figure 1 a of FeIn 2 S 4 / MoSe 2 spectrum, the peaks at 2θ of 23.7°, 27.8°, 33.7°, 44.3°, and 48.5° can be attributed to the (20), (311), (400), (511), and (440) crystal planes of FeIn 2 S 4 , which is in agreement with the standard card (JCPDS No. 80-0608). At the same time, the peaks at 2θ of 13.6°, 31.5°, 37.8°, and 55.8° can be attributed to the (002), (100), (103), and (110) crystal planes of MoSe 2 , which is in agreement with the standard JCPDS No. 29–0914 card of MoSe 2 . It can be seen from Figure 1 the partially enlarged XRD diagram of b that the XRD peak of Ce-FeIn 2 S 4 -MoSe 2 in Ce-FeIn 2 S 4 shifts 0.3° towards a smaller angle, proving that the lattice phase of FeIn 2 S 4 has changed, which is mainly due to the substitution of Ce doping for some of the main metal positions in FeIn 2 S 4 .

[0058] Figure 2 a and 2b are respectively the FeIn prepared in Comparative Example 1 2 S 4 / MoSe 2 photocatalyst and the Ce-FeIn prepared in Example 3 2 S 4 -MoSe2 High-resolution XPS Mo 3d spectra of the photocatalyst. As Figure 2 shown in a, for FeIn 2 S 4 / MoSe 2 , three fitting peaks appear in the Mo 3d spectrum, corresponding to Mo 3d in the MoSe 2 structure (232.5 eV), Mo 3d 3 / 2 (229.4 eV), and S2s (225.2 eV) in FeIn 5 / 2 S 2 respectively. This indicates that without Ce doping, no heterojunction structure with S-Mo covalent bonds is formed between FeIn 4 S 2 and MoSe 4 . Compared with the Mo 3d energy spectrum of FeIn 2 S 4 / MoSe 2 , in 2 b, two new strong peaks appear in the Ce-FeIn Figure 2 S 2 -MoSe 4 fitting peaks, corresponding to S-Mo 3d 2 (234.3 eV) and S-Mo 3d 2 S 4 formed between FeIn 2 and MoSe 3 / 2 (231.1 eV) respectively, indicating that Ce doping results in a tight heterojunction structure in Ce-FeIn 5 / 2 S 2 -MoSe 4 . 2 Perform photocurrent performance tests on the Ce-FeIn

[0059] photocatalyst prepared in Example 3 and the FeIn 2 S 4 -MoSe 2 photocatalyst prepared in Comparative Example 1. The results are as 2 shown in 4 2 . As can be seen from Figure 3 , under the same conditions, the photocurrent response intensity generated by Ce-FeIn Figure 3 S 2 -MoSe 4 is significantly greater than that of FeIn 2 S 2 / MoSe 4 , indicating that Ce-FeIn 2 2 , indicating that Ce-FeIn2 S 4 -MoSe 2 The S-Mo bond in the heterojunction can effectively promote the migration of photo-generated carriers, inhibit the recombination of electrons and holes, and thus improve the photo-quantum efficiency.

[0060] Figure 4 Ce-FeIn prepared for Example 3 2 S 4 -MoSe 2 UV-visible light absorption performance graph of. It can be seen from the figure that the prepared Ce-FeIn 2 S 4 -MoSe 2 has excellent absorption performance in the visible light region, indicating its excellent broadband visible light response characteristics and can be excited by visible light for photocatalytic reactions.

[0061] Using methyl orange as the target degradation substance, the photocatalytic degradation ability of the photocatalysts prepared in Examples 1-4 and Comparative Examples 1-5 for methyl orange in water was measured respectively.

[0062] The test method is as follows: Take 500 mL of methyl orange solution with an initial concentration of 50 mg / L, add 0.5 g of the heterojunction photocatalysts prepared in Examples 1-4 and Comparative Examples 1-5 respectively, oscillate at a constant temperature for 30 min. After the adsorption reaches equilibrium, turn on the visible light source and irradiate for 60 min to carry out the photocatalytic degradation experiment. After the experiment is over, take out the solution, centrifuge it with a high-speed centrifuge, and measure the concentration of methyl orange in the supernatant. According to the following formula Calculate the removal rate. In formula (1): R is the removal rate (%), C 0 is the initial concentration of methyl orange in the solution (mg / L), C e is the concentration of methyl orange in the solution after the photocatalytic reaction (mg / L). The results are shown in Table 1.

[0063] Table 1 shows the removal rates of methyl orange by the heterojunction photocatalysts prepared in Examples 1-4 and Comparative Examples 1-5

[0064] Selected material Residual concentration of methyl orange in solution (mg / L) Removal rate (%) Example 1 9.7 80.6 Example 2 7.1 85.9 Example 3 0.65 98.7 Example 4 4.4 91.3 Comparative example 1 19.6 60.9 Comparative example 2 21.4 57.3 Comparative example 3 24.1 51.9 Comparative example 4 32.4 35.3 Comparative example 5 13.8 72.4

[0065] It can be seen from Table 1 that the degradation rate of the target pollutant methyl orange in the solution is relatively high, indicating that the Ce-FeIn prepared by the present invention 2 S 4 -MoSe 2Heterojunction photocatalysts have good photocatalytic activity. As can be seen from Examples 1 to 4, the reaction temperature and the doping amount of Ce affect the activity of the prepared heterojunction catalysts. This is mainly because the reaction temperature affects the crystallization degree of the crystal phase of the prepared catalysts, and the doping amount of Ce is directly related to the generated S defects. Compared with Examples 1 to 4, the photocatalytic degradation activity of methyl orange in water body in Comparative Example 1 decreases, which is mainly due to FeIn without Ce doping 2 S 4 cannot form a tight heterojunction bond during the composite process, and thus cannot effectively carry out the heterotransport of photogenerated carriers. As can be seen from Comparative Examples 2 to 3, when the mass ratio of sodium molybdate dihydrate and Ce-FeIn 2 S 2 S 4 is 1:4 to 14, it is beneficial to the synergistic effect of FeIn 2 S 4 and MoSe 2 in the photocatalytic reaction. As can be seen from Comparative Examples 4 to 5, the reaction temperature affects the degree of heterocomposite of FeIn 2 S 4 and MoSe 2 precursors during the reaction in the autoclave, thereby affecting the formation of Ce-FeIn 2 S 4 -MoSe 2 and ultimately affecting the photocatalytic activity of the final product.

[0066] Take 500 mL of methyl orange solution with an initial concentration of 50 mg / L, and add 0.5 g of Ce-FeIn 2 S 4 -MoSe 2 prepared in Example 3, Ce-FeIn 2 S 4 photocatalyst and FeIn 2 S 4 / MoSe 2 photocatalyst prepared in Comparative Example 1, oscillate at a constant temperature for 30 min. After the adsorption reaches equilibrium, turn on the visible light source and irradiate for 60 min to carry out the photocatalytic degradation experiment. From the start to the end of the experiment, take out the solution at regular intervals, and after centrifugation with a high-speed centrifuge, measure the methyl orange concentration in the supernatant, and calculate the removal rate according to Equation (1). The results are as Figure 5 shown.

[0067] From Figure 5 it can be seen that the photocatalytic activity of Ce-FeIn 2 S 4 is significantly lower than that of the heterojunction system, and from Figure 5 it can be observed that Ce-FeIn 2 S4 -MoSe 2 The photocatalytic removal rate of methyl orange by the heterojunction photocatalyst is significantly higher than that of FeIn 2 S 4 / MoSe 2 photocatalyst, mainly because the doping of Ce in FeIn 2 S 4 promotes the reaction with MoSe 2 precursor to generate S-Mo bond connection, thereby enhancing Ce-FeIn 2 S 4 -MoSe 2 heterojunction improves the transfer efficiency of photo-generated carriers in the photocatalytic reaction, inhibits the recombination of electrons and holes, and thus enhances the photocatalytic activity.

[0068] In the photocatalyst prepared by the method of the present invention, FeIn 2 S 4 and MoSe 2 heterogeneous materials are atomically coupled at the heterojunction interface through S-Mo chemical bonds. This structural feature effectively optimizes the interfacial charge transport dynamics, promotes the cross-interface migration of photo-generated carriers, and further effectively improves the transport efficiency of photo-generated carriers between heterojunctions, inhibits the recombination of electron holes, and thus enhances the photocatalytic activity of the photocatalyst.

Claims

1. A method for preparing a Ce-FeIn2S4-MoSe2 heterojunction photocatalyst, characterized in that: Specifically, Ce-FeIn2S4 is first prepared by a solvothermal reaction; then the prepared Ce-FeIn2S4 is mixed with a precursor of MoSe2, and a Ce-FeIn2S4-MoSe2 heterojunction photocatalyst is prepared by a solvothermal reaction.

2. The preparation method according to claim 1, characterized in that: Ce-FeIn2S4 is specifically prepared by the following method: according to the stoichiometric ratio of iron, indium and sulfur, corresponding molar ratios of iron salt, indium salt and sulfur source are added to deionized water and mixed evenly to obtain solution A; cerium salt is added to ethylene glycol and stirred evenly to form solution B; solution B is added to solution A to carry out a solvothermal reaction, and after the reaction, the product is washed and dried to obtain Ce-FeIn2S4.

3. The preparation method according to claim 2, characterized in that: The iron salt is ferric chloride hexahydrate; the indium salt is indium chloride tetrahydrate; the sulfur source is thiourea or thioacetamide; and the cerium salt is cerium chloride heptahydrate or cerium nitrate hexahydrate.

4. The preparation method according to claim 2, characterized in that: The molar ratio of the iron salt, the indium salt, the sulfur source and the cerium salt is 1:2:4-8:0.06-0.

18.

5. The preparation method according to claim 2, characterized in that: The reaction temperature is 100-160° C., and the reaction time is 10-16 hours.

6. The preparation method according to claim 1, characterized in that: The specific process of preparing Ce-FeIn2S4-MoSe2 by mixing the precursors of Ce-FeIn2S4 and MoSe2 is: adding molybdenum salt, Se powder, sodium borohydride and Ce-FeIn2S4 into deionized water to obtain a mixed solution; placing the mixed solution under high temperature for reaction, and washing and drying the product after the reaction to obtain a Ce-FeIn2S4-MoSe2 photocatalyst.

7. The preparation method according to claim 6, characterized in that: The molybdenum salt is sodium molybdate dihydrate.

8. The preparation method according to claim 6, characterized in that: The molar ratio of the molybdenum salt, Se powder, sodium borohydride and Ce-FeIn2S4 is 1:2:5-10:4-14.

9. The preparation method according to claim 6, characterized in that: The reaction temperature is 120-200° C., and the reaction time is 12-18 hours.

10. The Ce-FeIn2S4-MoSe2 heterojunction photocatalyst prepared by the preparation method according to any one of claims 1 to 9, characterized in that: In the photocatalyst, Ce is doped in the main metal site lattice of the FeIn2S4 matrix, and FeIn2S4 and MoSe2 form an atomic-level heterogeneous interface through S-Mo covalent bonds.

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