A Fe-doped ZnIn2S4 photocatalyst, its preparation method and application

Abstract

This invention belongs to the field of photocatalytic nano-semiconductor material synthesis technology, and discloses an Fe-doped ZnIn2S4 photocatalyst, its preparation method, and its application. The preparation method of this invention includes the following steps: mixing a zinc source, an indium source, a sulfur source, and a ferrous source with water, and carrying out a hydrothermal reaction to obtain the Fe-doped ZnIn2S4 photocatalyst. Fe is a non-precious metal, and its doping content is trace; moreover, the hydrothermal method can synthesize ZnIn2S4 under relatively mild and simple synthesis conditions. The non-precious metal-doped ZnIn2S4 obtained by this invention, as a photocatalyst for hydrogen production, provides a new method for solving energy shortages and environmental pollution, and offers other possibilities for synthesizing green, economical, efficient, and universal photocatalysts.

Description

Technical Field

[0001] This invention relates to the field of photocatalytic nano-semiconductor material synthesis technology, and in particular to an Fe-doped ZnIn2S4 photocatalyst, its preparation method, and its application. Background Technology

[0002] Currently, energy crisis and environmental pollution are two major challenges facing society, primarily due to the widespread use of fossil fuels. The non-renewable nature and pollution of fossil fuels contradict the goal of sustainable development. Hydrogen energy, as a zero-pollution, high-energy-value clean energy source, may be able to shoulder this historical mission. Hydrogen energy can help humanity decarbonize, sequester carbon, and even achieve carbon-negative energy. For end-use energy, hydrogen can be used as a primary energy source, serving as a crucial vehicle for achieving a green and low-carbon transformation in energy consumption. Through hydrogen-electricity complementary systems, carbon dioxide emissions in the industrial energy sector can be reduced. In transportation and other sectors, replacing diesel and gasoline with hydrogen energy can also achieve emission reductions, or even "zero emissions." This plays a vital role in promoting the achievement of "dual carbon" goals.

[0003] There are various methods for producing hydrogen, such as hydrogen production from fossil fuels, hydrogen production through water electrolysis, hydrogen production from biomass, photochemical hydrogen production, thermochemical hydrogen production, and solar photocatalytic water splitting. Among these, photocatalytic hydrogen production technology is a promising green hydrogen production route. Compared with other hydrogen production technologies, photocatalytic hydrogen production equipment is simpler and has fewer structural components, thus resulting in lower costs. ZnIn2S4 is a high-performance visible-light activated ternary metal chalcogenide photocatalyst. Compared with single-metal chalcogenides (such as ZnS, Sb2S3, or CdS), ZnIn2S4 has a narrower band gap and does not contain toxic metal ions. Furthermore, the raw materials for synthesizing ZnIn2S4 are widely available. Its preparation method is simpler than other ternary metal chalcogenides (such as CuGaS2 or Zn3In2S6). Therefore, ZnIn2S4, with its broad application prospects, has attracted widespread attention from researchers in the field of photocatalysis.

[0004] Currently, the synthesis of ZnIn2S4 via hydrothermal and solvothermal methods typically uses solvents such as N,N-dimethylformamide (DMF), ethylene glycol (EG), methanol, or ethanol. Due to the high reducing power of methanol or ethanol, elemental sulfur is reduced during the synthesis of ZnIn2S4. Furthermore, cation-doped ZnIn2S4 is mainly concentrated in the noble metal field, which increases the synthesis cost of cation-doped ZnIn2S4. Summary of the Invention

[0005] The purpose of this invention is to provide an Fe-doped ZnIn2S4 photocatalyst, its preparation method, and its application, thereby solving the problems of existing technologies that often use methanol or ethanol as solvents and that the preparation of ZnIn2S4 photocatalysts usually involves the use of noble metal elements for doping, which increases costs.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for preparing Fe-doped ZnIn2S4 photocatalyst, comprising the following steps:

[0008] A zinc source, an indium source, a sulfur source, a ferrous source, and water were mixed and subjected to a hydrothermal reaction to obtain an Fe-doped ZnIn2S4 photocatalyst.

[0009] Preferably, in the preparation method, the zinc source includes zinc acetate, zinc chloride, zinc nitrate, or zinc sulfate; the indium source includes indium chloride, indium nitrate, or indium sulfate; the sulfur source includes thioacetamide or thiourea; and the ferrous source includes ferrous sulfate, ferrous nitrate, or ferrous chloride.

[0010] Preferably, in the preparation method, the molar ratio of the zinc source, the indium source and the sulfur source is 1:2:4 to 1:2:8;

[0011] The molar ratio of the zinc source to the volume of the water is 0.8 mmol: 50–80 mL.

[0012] Preferably, in the preparation method, the molar ratio of the zinc source to the ferrous source is 0.8:0.00055 to 1.12.

[0013] Preferably, in the preparation method, the temperature of the hydrothermal reaction is 120–180°C, and the time of the hydrothermal reaction is 12–36 h.

[0014] Preferably, in the preparation method, after the hydrothermal reaction, the process further includes: centrifugation, washing, and freeze-drying in sequence.

[0015] Preferably, in the preparation method, the washing reagents are ethanol and water, and the number of times ethanol is used for washing is independent of the number of times water is used for washing, which is 2 to 3 times.

[0016] The freeze-drying time is 12 to 24 hours.

[0017] Preferably, in the preparation method, the zinc source, indium source, sulfur source, ferrous source and water are mixed in the following manner: the zinc source, indium source, sulfur source and water are first mixed; the mixture obtained from the first mixing is then mixed with the ferrous source in a second manner.

[0018] The first mixing time is 2 to 2.5 hours;

[0019] The second mixing time is 30 to 45 minutes.

[0020] The present invention also provides an Fe-doped ZnIn2S4 photocatalyst prepared by the above preparation method.

[0021] This invention also provides an application of Fe-doped ZnIn2S4 photocatalyst in photocatalytic hydrogen production.

[0022] As can be seen from the above technical solution, compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) This invention proposes a simple hydrothermal method for preparing Fe-doped ZnIn2S4 nanosheets with interstitial doping. Zinc (zinc acetate, etc.), indium (indium chloride, etc.), sulfur (thioacetamide, etc.), and ferrous (ferrous sulfate, etc.) sources are used as reaction reagents, with the ferrous source serving as the dopant. In this preparation method, Fe is a non-noble metal, and its doping content is trace. Furthermore, the hydrothermal method can synthesize ZnIn2S4 under relatively mild and simple synthesis conditions. ZnIn2S4, as a hydrogen collector, can adsorb water molecules and decompose them to generate H*, which accumulates on the ZnIn2S4 surface. The addition of Fe induces a surface plasmon resonance effect, affecting the charge density of S on the ZnIn2S4 surface, causing H* to migrate from the S surface to the Fe surface and collide with it to generate H2. Therefore, the non-noble metal-doped ZnIn2S4 prepared in this invention, as a photocatalyst for hydrogen production, is of pioneering significance for the synthesis of semiconductor nanomaterials, provides a new method for solving energy shortages and environmental pollution, and offers other possibilities for the synthesis of green, economical, efficient, and universal photocatalysts.

[0024] (2) The raw materials of the present invention are readily available and have low cost. At the same time, the method of the present invention for preparing Fe-doped ZnIn2S4 photocatalyst is simple, the reaction is easy to operate, the reaction time is short, and it can realize large-scale industrial production. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0026] Figure 1 A schematic diagram of the preparation process of Fe-doped ZnIn2S4 photocatalyst;

[0027] Figure 2 The XRD patterns of the photocatalysts obtained in Examples 1-3 and Comparative Example 1 are shown below.

[0028] Figure 3 The hydrogen production results are for the photocatalysts obtained in Examples 1-3;

[0029] Figure 4 The hydrogen production results are for the photocatalysts obtained in Examples 4-6;

[0030] Figure 5 The XRD patterns of the photocatalysts obtained in Examples 7-9 and Comparative Example 1 are shown below.

[0031] Figure 6 The XRD patterns of the photocatalysts obtained in Comparative Examples 1-5 are shown.

[0032] Figure 7 A schematic diagram illustrating the principle of preparing ZnIn2S4 in water;

[0033] Figure 8 The hydrogen production results are for the photocatalysts obtained in Examples 2, 5, 10-14. Detailed Implementation

[0034] This invention provides a method for preparing Fe-doped ZnIn2S4 photocatalyst, comprising the following steps:

[0035] A zinc source, an indium source, a sulfur source, a ferrous source, and water were mixed and subjected to a hydrothermal reaction to obtain an Fe-doped ZnIn2S4 photocatalyst.

[0036] In this invention, the preferred method for mixing the zinc source, indium source, sulfur source, ferrous source and water is to first mix the zinc source, indium source, sulfur source and water; and then to second mix the mixture obtained from the first mixing with the ferrous source.

[0037] In this invention, the first mixing time is preferably 2 to 2.5 hours, more preferably 2 to 2.2 hours, and even more preferably 2 hours.

[0038] In this invention, the second mixing time is preferably 30 to 45 minutes, more preferably 30 to 40 minutes, and even more preferably 30 minutes.

[0039] In this invention, the zinc source preferably includes zinc acetate (Zn(CH3COO)2·2H2O), zinc chloride, zinc nitrate (Zn(NO3)2·6H2O) or zinc sulfate (ZnSO4·7H2O), more preferably zinc acetate or zinc chloride, and more preferably zinc acetate.

[0040] In this invention, the indium source preferably includes indium chloride (InCl3·4H2O), indium nitrate (In(NO3)3·4H2O) or indium sulfate, more preferably indium chloride or indium nitrate, and more preferably indium chloride.

[0041] In this invention, the sulfur source preferably includes thioacetamide (CH3CSNH2) or thiourea, and more preferably thioacetamide.

[0042] In this invention, the ferrous source preferably includes ferrous sulfate (FeSO4·7H2O), ferrous nitrate or ferrous chloride, more preferably ferrous sulfate or ferrous chloride, and even more preferably ferrous sulfate.

[0043] In this invention, the molar ratio of the zinc source, the indium source and the sulfur source is preferably 1:2:4 to 1:2:8, more preferably 1:2:5.3375 to 1:2:8, and even more preferably 1:2:5.3375.

[0044] In this invention, the molar ratio of the zinc source to the volume of the water is preferably 0.8 mmol: 50-80 mL, more preferably 0.8 mmol: 55-70 mL, and even more preferably 0.8 mmol: 60 mL.

[0045] In this invention, the molar ratio of the zinc source to the ferrous source is preferably 0.8:0.00055 to 1.12, more preferably 0.8:0.00055 to 0.00875, and even more preferably 0.8:0.0011.

[0046] In this invention, the temperature of the hydrothermal reaction is preferably 120-180°C, more preferably 150-180°C, and even more preferably 180°C.

[0047] In this invention, the hydrothermal reaction time is preferably 12 to 36 hours, more preferably 18 to 30 hours, and even more preferably 24 hours.

[0048] In this invention, the hydrothermal reaction preferably further includes: centrifugation, washing, and freeze-drying in sequence.

[0049] In this invention, the centrifugation speed is preferably 8000-10000 rpm, more preferably 8000-9000 rpm, and even more preferably 8000 rpm.

[0050] In this invention, the centrifugation time is preferably 5 to 9 minutes, more preferably 5 to 7 minutes, and even more preferably 5 minutes.

[0051] In this invention, the washing reagent is preferably ethanol and water.

[0052] In this invention, the washing with ethanol is preferably performed 2 to 3 times, and more preferably 2 times.

[0053] In this invention, the number of times water washing is used is preferably 2 to 3 times, more preferably 3 times.

[0054] In this invention, the atmosphere for freeze-drying is preferably a vacuum.

[0055] In this invention, the freeze-drying time is preferably 12 to 24 hours, more preferably 12 to 18 hours, and even more preferably 12 hours.

[0056] The present invention also provides an Fe-doped ZnIn2S4 photocatalyst prepared by the above preparation method.

[0057] This invention also provides an application of Fe-doped ZnIn2S4 photocatalyst in photocatalytic hydrogen production.

[0058] In this invention, the method of application is not limited, and any solution known in the art is acceptable.

[0059] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0060] Example 1

[0061] This embodiment provides a method for preparing Fe-doped ZnIn2S4 photocatalyst (a schematic diagram of the preparation process is shown below). Figure 1 (As shown), including the following steps:

[0062] Weigh 0.8 mmol Zn(CH3COO)2·2H2O, 1.6 mmol InCl3·4H2O and 6.4 mmol CH3CSNH2(TAA), add them to 80 mL of deionized water, stir for 2 h to obtain the precursor solution;

[0063] Weigh 0.14 mmol FeSO4·7H2O and dissolve it in the precursor solution, then stir for 30 min;

[0064] The stirred mixture was transferred to a 100 mL stainless steel reactor lined with polytetrafluoroethylene and sealed. After heating at 180 °C for 24 h, it was allowed to cool naturally to room temperature. The precipitate was centrifuged at 8000 rpm for 5 min and washed twice with anhydrous ethanol and three times with deionized water. The washed product was freeze-dried under vacuum for 12 h to obtain the Fe-doped ZnIn2S4 photocatalyst, denoted as Fe0.14@ZIS-S6.4.

[0065] Example 2

[0066] This embodiment provides a method for preparing Fe-doped ZnIn2S4 photocatalyst. The difference from Example 1 is that the amount of CH3CSNH2 is modified to 4.27 mmol, while other parameters and conditions are the same as in Example 1. This method is denoted as Fe0.14@ZIS-S4.27.

[0067] Example 3

[0068] This embodiment provides a method for preparing Fe-doped ZnIn2S4 photocatalyst, which differs from Example 1 in that the amount of CH3CSNH2 is modified to 3.2 mmol, while other parameters and conditions are the same as in Example 1, denoted as Fe0.14@ZIS-S3.2.

[0069] Comparative Example 1

[0070] This comparative example provides a method for preparing a ZnIn2S4 photocatalyst. The difference from Example 1 is that FeSO4·7H2O is removed, while other parameters and conditions are the same as in Example 1. This method is referred to as ZIS or deionized water-ZIS.

[0071] The crystal structure and phase composition of the photocatalysts obtained in Examples 1-3 and Comparative Example 1 were determined by XRD, and the results are as follows: Figure 2 As shown. By Figure 2 It was found that all catalysts belonged to the hexagonal ZnIn2S4 phase (JCPDS No. 65-2023), with characteristic peaks located near 21.55°, 27.50°, 30.38°, 39.56°, 47.15°, 52.37°, and 55.45°, corresponding to the {006}, {102}, {104}, {108}, {102}, {110}, {116}, and {022} lattice phases, respectively. No impurity diffraction peaks were detected in Examples 1-3, indicating that the introduction of Fe did not affect the crystal structure of ZnIn2S4. With the increase of S content, the diffraction peaks gradually shifted more towards smaller angles. When the S content reached 4.27 mmol, the angle shift towards smaller angles became smaller, which is related to the Fe doping content in ZnIn2S4.

[0072] Example 4

[0073] This embodiment provides a method for preparing Fe-doped ZnIn2S4 photocatalyst. The difference from Example 1 is that the amount of FeSO4·7H2O is modified to 0.07 mmol, while other parameters and conditions are the same as in Example 1. This method is denoted as Fe0.07@ZIS-S6.4.

[0074] Example 5

[0075] This embodiment provides a method for preparing Fe-doped ZnIn2S4 photocatalyst. The difference from Example 2 is that the amount of FeSO4·7H2O is modified to 0.07 mmol, while other parameters and conditions are the same as in Example 2. This method is denoted as Fe0.07@ZIS-S4.27.

[0076] Example 6

[0077] This embodiment provides a method for preparing Fe-doped ZnIn2S4 photocatalyst. The difference from Example 3 is that the amount of FeSO4·7H2O is modified to 0.07 mmol, while other parameters and conditions are the same as in Example 3. This method is denoted as Fe0.07@ZIS-S3.2.

[0078] Test methods for photocatalytic hydrogen production performance:

[0079] The test was conducted in a Labsolar-I (AG) (Pofilai, China) all-quartz glass automated online trace gas analysis system with exposure and sealing at the top, measuring 150m. A 300W xenon lamp (PLS-SXE300) equipped with an ultraviolet cutoff filter (λ>420nm) was used as the light source and placed 10cm directly above the reactor. The specific operation procedure was as follows: 5mg of photocatalyst sample was weighed and added to 100mL of aqueous solution (containing 0.02mol / L ascorbic acid as a sacrificial agent), and sonicated for 1min to ensure thorough dispersion of the catalyst. Before the hydrogen evolution experiment, the reactor was purged with argon gas for 30min to remove air from the reactor. During the reaction, the solution was continuously stirred to maintain homogeneity, and the reactor was kept at 10℃ using circulating cooling water. Finally, the amount of gas produced from the sealed quartz reactor every half hour was measured using a gas chromatograph (FLGC.9790I, TCD) to evaluate the hydrogen production performance.

[0080] The effects of different S contents on hydrogen production were investigated using the aforementioned photocatalytic hydrogen production performance testing method. The results are as follows: Figure 3 , Figure 4 As shown in the two figures, the hydrogen production is highest when the S content is 4.27 mmol, therefore the optimal S content is 4.27 mmol.

[0081] Example 7

[0082] This embodiment provides a method for preparing Fe-doped ZnIn2S4 photocatalyst. The difference from Example 2 is that the amount of FeSO4·7H2O is modified to 1.12 mmol, while other parameters and conditions are the same as in Example 2. This method is denoted as Fe1.12@ZIS-S4.27.

[0083] Example 8

[0084] This embodiment provides a method for preparing Fe-doped ZnIn2S4 photocatalyst. The difference from Example 2 is that the amount of FeSO4·7H2O is modified to 0.56 mmol, while other parameters and conditions are the same as in Example 2. This method is denoted as Fe0.56@ZIS-S4.27.

[0085] Example 9

[0086] This embodiment provides a method for preparing Fe-doped ZnIn2S4 photocatalyst. The difference from Example 2 is that the amount of FeSO4·7H2O is modified to 0.28 mmol, while other parameters and conditions are the same as in Example 2. This method is denoted as Fe0.28@ZIS-S4.27.

[0087] The crystal structures and phases of the photocatalysts obtained in Examples 7-9 and Comparative Example 1 were determined by XRD, and the results are as follows: Figure 5 As shown. By Figure 5 It can be seen that all catalysts belong to the hexagonal ZnIn2S4 phase (JCPDS No. 65-2023), with characteristic peaks located near 21.55°, 27.50°, 30.38°, 39.56°, 47.15°, 52.37°, and 55.45°, corresponding to the {006}, {102}, {104}, {108}, {102}, {110}, {116}, and {022} lattice phases, respectively. No impurity diffraction peaks were detected in Examples 7-9, indicating that the introduction of Fe does not affect the crystal structure of ZnIn2S4. With the increase of Fe... 2+ With increasing Fe content, the diffraction peaks gradually shift towards smaller angles, and the intergranular spacing increases. This is related to Fe 2+ ionic radius Greater than Zn 2+ ionic radius related.

[0088] Comparative Example 2

[0089] This comparative example provides a method for preparing a ZnIn2S4 photocatalyst. The difference from Comparative Example 1 is that deionized water is replaced with methanol, while other parameters and conditions are the same as in Comparative Example 1. This method is referred to as methanol-ZIS.

[0090] Comparative Example 3

[0091] This comparative example provides a method for preparing Fe-doped ZnIn2S4 photocatalyst. The difference from Example 7 is that deionized water is replaced with methanol, while other parameters and conditions are the same as in Example 7. This method is denoted as methanol-Fe1.12@ZIS.

[0092] Comparative Example 4

[0093] This comparative example provides a method for preparing Fe-doped ZnIn2S4 photocatalyst. The difference from Example 8 is that deionized water is replaced with methanol, while other parameters and conditions are the same as in Example 8. This method is denoted as methanol-Fe0.56@ZIS.

[0094] Comparative Example 5

[0095] This comparative example provides a method for preparing Fe-doped ZnIn2S4 photocatalyst. The difference from Example 9 is that deionized water is replaced with methanol, while other parameters and conditions are the same as in Example 9. This method is denoted as methanol-Fe0.28@ZIS.

[0096] The crystal structure and phase composition of the photocatalysts obtained in Comparative Examples 1–5 were determined by XRD, and the results are as follows: Figure 6 As shown. By Figure 6 It is known that ZnIn2S4 synthesized using deionized water belongs to the hexagonal ZnIn2S4 phase (JCPDS No. 65-2023), with characteristic peaks located near 21.64°, 27.82°, 30.32°, 39.14°, 47.16°, 52.38°, and 56.54°, corresponding to the {006}, {102}, {104}, {108}, {102}, {110}, {116}, and {022} lattice phases, respectively. Diffraction peaks of elemental sulfur (S) were detected in ZnIn2S4 synthesized using methanol as a solvent (JCPDS No. 24-1251), and elemental sulfur diffraction peaks were also observed in Fe@ZnIn2S4 synthesized using methanol, indicating that elemental sulfur was generated during the synthesis process due to the high reducing power of methanol.

[0097] The principle of this invention for preparing ZnIn2S4 in water is as follows: Figure 7 As shown, in solution, In 3+ and Zn 2+ It adsorbs H2O to form a tetrahedron [In(H2O)4]. 3+ [Zn(H2O)4] 2+ And octahedral [In(H2O)6] 3+ It then forms three different complexes with TAA, namely tetrahedral [In(TAA)4]. 3+ [Zn(TAA)4] 2+ And octahedron [In(TAA)6] 3+ Through stirring, InS6, In-S4, and Zn-S4 were further formed. At the same time, these newly formed metallic sulfur molecules further combined in situ to form a thermodynamically stable hexagonal ZnIn2S4 phase.

[0098] Example 10

[0099] This embodiment provides a method for preparing Fe-doped ZnIn2S4 photocatalyst. The difference from Example 2 is that the amount of FeSO4·7H2O is modified to 0.035 mmol, while other parameters and conditions are the same as in Example 2. This method is denoted as Fe0.035@ZIS-S4.27.

[0100] Example 11

[0101] This embodiment provides a method for preparing Fe-doped ZnIn2S4 photocatalyst. The difference from Example 2 is that the amount of FeSO4·7H2O is modified to 0.00875 mmol, while other parameters and conditions are the same as in Example 2. This method is denoted as Fe0.00875@ZIS-S4.27.

[0102] Example 12

[0103] This embodiment provides a method for preparing Fe-doped ZnIn2S4 photocatalyst. The difference from Example 2 is that the amount of FeSO4·7H2O is modified to 0.00219 mmol, while other parameters and conditions are the same as in Example 2. This method is denoted as Fe0.00219@ZIS-S4.27.

[0104] Example 13

[0105] This embodiment provides a method for preparing Fe-doped ZnIn2S4 photocatalyst. The difference from Example 2 is that the amount of FeSO4·7H2O is modified to 0.0011 mmol, while other parameters and conditions are the same as in Example 2. This method is denoted as Fe0.0011@ZIS-S4.27.

[0106] Example 14

[0107] This embodiment provides a method for preparing Fe-doped ZnIn2S4 photocatalyst. The difference from Example 2 is that the amount of FeSO4·7H2O is modified to 0.00055 mmol, while other parameters and conditions are the same as in Example 2. This method is denoted as Fe0.00055@ZIS-S4.27.

[0108] The aforementioned test method for photocatalytic hydrogen production performance was used to investigate the effect of different Fe contents on hydrogen production. The results are as follows: Figure 8 As shown. By Figure 8 It can be seen that as the Fe content increases, the hydrogen production exhibits a Gaussian distribution, and the hydrogen production reaches its maximum when the Fe content is 0.0011 mmol.

[0109] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. The application of an Fe-doped ZnIn2S4 photocatalyst in photocatalytic hydrogen production, characterized in that, The preparation method of the Fe-doped ZnIn2S4 photocatalyst includes the following steps: A zinc source, an indium source, a sulfur source, a ferrous source, and water were mixed and subjected to a hydrothermal reaction to obtain an Fe-doped ZnIn2S4 photocatalyst. The molar ratio of the zinc source, the indium source and the sulfur source is 1:2:4 to 1:2:8; The molar ratio of the zinc source to the ferrous source is 0.8:0.00055~0.00875; The hydrothermal reaction temperature is 120~180℃, and the hydrothermal reaction time is 12~36h.

2. The application according to claim 1, characterized in that, The zinc source includes zinc acetate, zinc chloride, zinc nitrate, or zinc sulfate; the indium source includes indium chloride, indium nitrate, or indium sulfate; the sulfur source includes thioacetamide or thiourea; and the ferrous source includes ferrous sulfate, ferrous nitrate, or ferrous chloride.

3. The application according to claim 1 or 2, characterized in that, The molar ratio of the zinc source to the volume of the water is 0.8 mmol: 50~80 mL.

4. The application according to claim 1, characterized in that, The hydrothermal reaction process also includes sequential centrifugation, washing, and freeze-drying.

5. The application according to claim 4, characterized in that, The washing reagents are ethanol and water, and the number of times ethanol is used for washing is independent of the number of times water is used for washing, which is 2 to 3 times. The freeze-drying time is 12-24 hours.

6. The application according to claim 1, characterized in that, The specific method for mixing the zinc source, indium source, sulfur source, ferrous source, and water is as follows: the zinc source, indium source, sulfur source, and water are first mixed; the mixture obtained from the first mixing is then second mixed with the ferrous source. The first mixing time is 2~2.5h; The second mixing time is 30-45 minutes.

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