Cadmium sulfide-zinc sulfide-cuprous sulfide nano-heterostructure material and preparation method and application thereof

Abstract

The application discloses a preparation method of a cadmium sulfide-zinc sulfide-cuprous sulfide nano heterojunction material, and belongs to the technical field of nanometer materials. The application further provides the cadmium sulfide-zinc sulfide-cuprous sulfide nano heterojunction material and application thereof. The cadmium sulfide-zinc sulfide-cuprous sulfide nano heterojunction material prepared by the application has high photocatalytic hydrogen evolution efficiency and high stability.

Description

Technical Field

[0001] This invention belongs to the field of catalytic materials, and particularly relates to a heterostructure material, its preparation method, and its application. Background Technology

[0002] Utilizing photocatalysis technology to solve energy and environmental problems is of great significance. Photocatalytic hydrogen production, which converts solar energy into clean hydrogen energy to meet continuous energy demands, is a feasible approach. Hydrogen has a high energy density, and its combustion product is only water, making it an excellent green energy source. Semiconductors are common catalysts in photocatalytic hydrogen production. The light absorption capacity, carrier separation efficiency, and photogenerated carrier migration rate of semiconductors all play a crucial role in the performance of photocatalytic hydrogen production. Severe photogenerated charge recombination in single semiconductor materials leads to low photocatalytic efficiency and stability, significantly limiting their applications, especially in photocatalytic hydrogen evolution.

[0003] Among many semiconductors, metal sulfides have advantages such as good light absorption performance, and are attracting more and more attention as a new type of photocatalytic material. However, the low efficiency of hydrogen evolution photocatalysis by single metal sulfides is a problem that urgently needs to be solved.

[0004] To address the aforementioned issues, researchers often employ band structure construction and co-catalyst loading techniques on single materials. Numerous methods exist for constructing composite materials, including doping, seed growth, and co-precipitation. These methods can modulate the band structure of the material, thereby improving light absorption and photogenerated carrier separation capabilities to some extent. However, these methods result in composite materials with limited components and difficult morphological control. Furthermore, the ohmic coupling of these composites leads to lattice mismatch between components, resulting in numerous lattice defects at the heterojunction interface, which inhibits effective separation of photogenerated charges, limiting catalytic efficiency and stability. Loading noble metal co-catalysts can significantly improve the photocatalytic hydrogen evolution efficiency of materials, but their high cost also restricts their application. Therefore, synthesizing a low-cost, high-efficiency, and highly stable catalytic material remains a challenge that needs to be overcome. Summary of the Invention

[0005] To address the existing technical problems, this invention provides a low-cost, high-efficiency, and high-stability cadmium sulfide-zinc sulfide-cuprous sulfide nanoheterostructure material, its preparation method, and its applications. The resulting cadmium sulfide-zinc sulfide-cuprous sulfide single-particle nanoheterostructure material exhibits high hydrogen evolution efficiency and corrosion resistance, improving the performance of photocatalysts without using precious metal co-catalysts. To achieve the above objectives, this invention adopts the following technical solution:

[0006] A method for preparing a cadmium sulfide-zinc sulfide-cuprous sulfide nanoheterojunction material includes the following steps:

[0007] (1) Add oleylamine and copper chloride to the first container and seal it, stir, evacuate, and heat it; add tert-dodecyl mercaptan to the second container and evacuate, and heat it.

[0008] (2) Connect the first container and the second container with a tubing (such as a double-ended injection needle) and introduce an inert gas into the second container. Due to the pressure difference, tert-dodecyl mercaptan is injected into the first container. The solution in the first container is heated to react. Finally, it is cooled, washed, and dried to obtain cuprous sulfide nanoparticles.

[0009] (3) In the third container, octadecene, oleylamine and zinc chloride are mixed and sealed, stirred, evacuated and then inert gas is introduced and heated to react to obtain the precursor of Zn.

[0010] (4) The cuprous sulfide nanoparticles obtained in step (2) are ultrasonically dispersed in octadecene to obtain a dispersion (ultrasonic treatment time is 15-20 min, preferably 15 min). The dispersion and tri-n-octylphosphine are then added to the Zn precursor obtained in step (3) and reacted to obtain a zinc sulfide-cuprous sulfide particle mixture. When dispersing the cuprous sulfide nanoparticles, tri-n-octylphosphine is not added to the ultrasonic bottle to slow down the etching phenomenon of cuprous sulfide.

[0011] (5) In the fourth container, octadecene, oleylamine and cadmium chloride are mixed and sealed, stirred, vacuumed and heated to react to obtain the precursor of Cd;

[0012] (6) Connect the third container and the fourth container with a tubing (such as a double-ended injection needle). Due to the pressure difference, the zinc sulfide-cuprous sulfide particle mixture is injected into the fourth container to carry out the reaction.

[0013] (7) The reaction was terminated by injecting a reaction terminator into the fourth container. Finally, the container was washed and dried to obtain the cadmium sulfide-zinc sulfide-cuprous sulfide nanoheterojunction material.

[0014] The method for preparing cadmium sulfide-zinc sulfide-cuprous sulfide nanoheterojunction material of the present invention adopts a hot injection method in the preparation of cuprous sulfide. Tertiary dodecyl mercaptan that has been heated is added to the first container, avoiding the high temperature and high pressure required in the traditional hydrothermal solvothermal method for preparing cuprous sulfide. The organic solvent is used to increase the activation energy of the reaction. The reaction is carried out in relatively conventional experimental equipment to obtain monodisperse, high-quality, and excellent-morphology (sheet-like) cuprous sulfide nanocrystals with high reactivity, which is conducive to the subsequent cation exchange reaction and to obtain a composite nanoheterojunction material with controllable morphology.

[0015] This invention directly injects a zinc sulfide-cuprous sulfide particle mixture into the Cd precursor for mixing and reaction, instead of filtering, washing, drying, and then redispersing the zinc sulfide-cuprous sulfide particle mixture before reacting it with the Cd precursor. This simplifies the process and reduces product loss. Furthermore, the zinc sulfide-cuprous sulfide particles are not exposed to an oxygen atmosphere, allowing the reaction to be in equilibrium. This results in high reactivity of the raw materials, which is beneficial for the subsequent cadmium cation exchange reaction to prepare the composite nano-heterojunction material.

[0016] In the above preparation method, preferably, before injecting the reaction terminator into the fourth container to terminate the reaction, the solution in the fourth container is first subjected to a heating-holding-ice-water cooling treatment (in an oxygen-free environment), and then n-hexane is injected to terminate the reaction. The heating-holding-ice-water cooling treatment involves heating the solution in the fourth container to 140-150℃ (preferably 140 min), holding it at that temperature for 5-10 min (preferably 5 min), and then rapidly cooling it with ice water. Our research shows that, considering the complex structure of the nano-heterojunction material of the present invention, after multiple cation exchange reactions, directly subjecting the solution in the fourth container to a heating-holding-ice-water cooling treatment after the reaction is completed further improves the performance of the synthesized material, reduces defects and stress at the contact interfaces of various materials, and effectively improves the photocatalytic stability and catalytic performance of the composite heterojunction material.

[0017] In the above preparation method, preferably, in step (1), the molar ratio of oleylamine to copper chloride is (20-25):(2-4), and the molar ratio of copper chloride to tert-dodecyl mercaptan is 1:(3-24), preferably 1:(6-12), and more preferably 1:12; the solutions in both the first and second containers are heated to 80-90℃ and then kept at that temperature for 30-40 minutes. The oleylamine mainly coordinates with copper chloride, and the tert-dodecyl mercaptan provides an organic sulfur source. The amount of tert-dodecyl mercaptan affects the free energy of the system, thus affecting the degree of orientation growth of the particles. Increasing the amount of tert-dodecyl mercaptan weakens the orientation growth of the nanosheets and reduces the radial-to-axial ratio of the particles. The amount of tert-dodecyl mercaptan needs to be controlled to facilitate the subsequent reaction with the Zn and Cd precursors to obtain heterostructure materials.

[0018] In the above preparation method, preferably, in step (2), when heating the reaction, the temperature is raised to 160-190℃ (preferably 175-185℃, more preferably 180℃) and reacted for 15-30 minutes, preferably 30 minutes, and then cooled to 15-50℃.

[0019] In the above preparation method, preferably, in step (3), the molar ratio of octadecene, oleylamine and zinc chloride is (120-130):(95-105):1; when heating the reaction, the temperature is raised to 160-190℃ (preferably 170-180℃, more preferably 180℃) and reacted for 15-30 min, preferably 30 min, and then cooled to 85-115℃ and kept warm.

[0020] In the above preparation method, preferably, in step (4), the molar ratio of cuprous sulfide nanoparticles and tri-n-octylphosphine added to the Zn precursor is 1:(7-12), preferably 1:(7-8), the amount of cuprous sulfide nanoparticles added is controlled so that the molar ratio of cuprous sulfide nanoparticles to zinc chloride is (0.9-1.2):(0.3-0.5), preferably 3:1, and the reaction time after addition is 30-60 min, preferably 30 min.

[0021] In the above preparation method, preferably, in step (5), the molar ratio of octadecene, oleylamine and cadmium chloride is (120-130):(95-105):1; when heating the reaction, the temperature is raised to 180-210℃ (preferably 190-200℃, more preferably 200℃) and reacted for 15-30 minutes, and then cooled to 50-85℃ and kept warm.

[0022] In the above preparation method, preferably, in step (6), the amount of zinc sulfide-cuprous sulfide particle mixture added is controlled to have a molar ratio of zinc sulfide-cuprous sulfide particles and cadmium chloride of (0.9-1.2):(0.2-0.3), preferably 3:1, and the reaction time after addition is 15-30 min.

[0023] Different cation exchange temperatures lead to kinetic differences and variations in exchange sites. As the temperature increases, multiple sites on the particle surface simultaneously overcome the cation exchange barrier, reducing the influence of the preferred nucleation site (morphology-directed effect), resulting in different elemental distributions. This is particularly true in sequential cation exchange, where the first element to be exchanged is affected, as later-exchanged elements preferentially exchange along the already formed heterojunction interface. These differences in elemental distribution have a significant impact on the transfer of photogenerated charges, leading to variations in photocatalytic efficiency. This invention requires strict control of the temperatures in the Zn and Cd precursor solutions to facilitate the exchange reaction and obtain heterostructured materials with high photocatalytic efficiency. Furthermore, the proportions of each raw material in the above reaction steps also determine the product performance; controlling these proportions helps obtain high-performance composite nanoheterojunction materials.

[0024] As a general technical concept, the present invention also provides a cadmium sulfide-zinc sulfide-cuprous sulfide nanoheterojunction material obtained by the above preparation method.

[0025] As a general technical concept, this invention also provides the application of the above-mentioned cadmium sulfide-zinc sulfide-cuprous sulfide nanoheterojunction material in photocatalytic hydrogen evolution catalysts. The cadmium sulfide-zinc sulfide-cuprous sulfide nanoheterojunction material prepared by this invention exhibits superior hydrogen evolution performance: under one solar radiation intensity, in an aqueous solution containing 0.1 M Na₂S and 0.1 M Na₂SO₃, the highest photocatalytic hydrogen evolution rate of cadmium sulfide-zinc sulfide-cuprous sulfide is 3.01 mmol·g⁻¹. -1 ·h -1 It is 120 times higher than pure cadmium sulfide, and its photocatalytic hydrogen evolution stability reaches 24h.

[0026] The preparation method of the cadmium sulfide-zinc sulfide-cuprous sulfide nanoheterojunction material of the present invention first utilizes a hot-injection method, a simple process to synthesize highly active cuprous sulfide nanoparticles, followed by continuous cation exchange. Through process step and parameter control of the cation exchange reaction, the ion exchange of zinc and cadmium is facilitated, ultimately yielding the cadmium sulfide-zinc sulfide-cuprous sulfide nanoheterojunction material. Through the synergistic effect of cadmium sulfide, zinc sulfide, and cuprous sulfide, the material exhibits high stability and photocatalytic hydrogen evolution efficiency. In particular, after cation exchange, a heating-holding-ice-water cooling treatment reduces defects and stress at the interface of each material, further enhancing the stability and photocatalytic hydrogen evolution efficiency of the composite nanoheterojunction material.

[0027] Compared with the prior art, the advantages of the present invention are as follows:

[0028] 1. The cadmium sulfide-zinc sulfide-cuprous sulfide nanoheterojunction material prepared by this invention has high photocatalytic hydrogen evolution efficiency and strong stability:

[0029] To address the problems of low catalytic efficiency and severe photocorrosion in traditional metal sulfide semiconductor catalysis, this material employs a heterojunction construction approach. Using a hot-injection method and a cation exchange method, a composite nano-heterojunction material with synergistic effects is prepared. This material possesses a continuous sublattice structure, reducing interface defects and promoting the effective separation and transfer of photogenerated carriers. Utilizing the high mobility of copper in cuprous sulfide as the parent material for exchange and as a hole-assisted catalyst, the photocorrosion effect of cadmium sulfide is suppressed. Cadmium sulfide provides photogenerated carriers, and its potential matches well with the hydrogen evolution potential, serving as a reaction site for hydrogen, resulting in high photocatalytic hydrogen evolution efficiency. Zinc sulfide is used as a capping agent, exhibiting a passivation effect in this material, improving its stability and further enhancing its photocatalytic hydrogen evolution efficiency.

[0030] 2. The preparation method of the present invention is simple and low in cost: The present invention prepares complex multi-element single-particle nano-heterostructure materials by means of the traditional cation exchange method. It can realize the preparation of photocatalysts with simple process equipment and at relatively low temperature. Moreover, the continuous sequential cation exchange greatly shortens the preparation time, which provides the possibility for further industrialization. Attached Figure Description

[0031] 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. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 The X-ray diffraction pattern of the cadmium sulfide-zinc sulfide-cuprous sulfide nanoheterostructure material prepared in Example 1 is shown.

[0033] Figure 2 The image shows a transmission electron microscope (TEM) image of the cadmium sulfide-zinc sulfide-cuprous sulfide nanoheterostructure material prepared in Example 1.

[0034] Figure 3 The X-ray diffraction pattern of the cuprous sulfide nanomaterial prepared in Comparative Example 1 is shown.

[0035] Figure 4 The image shows a transmission electron microscope (TEM) image of the cuprous sulfide nanomaterials prepared in Comparative Example 1. Detailed Implementation

[0036] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0037] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0038] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0039] Example 1:

[0040] A method for preparing a cadmium sulfide-zinc sulfide-cuprous sulfide nanostructure material includes the following steps:

[0041] (1) Add 20 mmol of oleylamine and 4 mmol of anhydrous copper chloride to a 100 mL round-bottom flask, seal it, stir it magnetically, and evacuate it three times at room temperature while introducing inert gas; then heat it to 80 °C and keep it at that temperature for 15 min; add 48 mmol of tert-dodecyl mercaptan to another flask, seal it, and evacuate it three times at room temperature while introducing inert gas, and then heat it to 80 °C.

[0042] (2) Connect the two flasks in step (1) with a double-ended injection needle, and introduce a small amount of argon gas into the flask containing tert-dodecyl mercaptan. Due to the pressure difference, tert-dodecyl mercaptan is injected into the flask containing copper chloride. Remove the injection needle, heat the solution to 180°C and react for 30 min. Finally, cool it to 15°C in an ice-water bath, wash and dry to obtain cuprous sulfide nanoparticles.

[0043] (3) Add 36 mmol octadecene, 29 mmol oleylamine and 0.3 mmol zinc chloride to a 100 mL round bottom flask, mix and seal, start magnetic stirring, evacuate three times and then introduce inert gas; then heat to 180 °C and keep warm for 30 min to obtain the Zn precursor, and then slowly cool to 85 °C to wait for the reaction.

[0044] (4) 0.9 mmol cuprous sulfide nanoparticles were ultrasonically dispersed in 6 mmol octadecene and injected together with 7 mmol tri-n-octylphosphine into the Zn precursor. The reaction was carried out for 30 min to obtain a zinc sulfide-cuprous sulfide particle mixture.

[0045] (5) In another flask, 36 mmol of octadecene, 29 mmol of oleylamine and 0.3 mmol of cadmium chloride were added to a 100 mL round-bottom flask and mixed. The flask was then sealed and magnetically stirred. After three vacuum cycles, an inert gas was introduced. The temperature was then raised to 200 °C and kept at that temperature for 15 min to obtain the precursor of Cd. The temperature was then slowly cooled to 85 °C to allow the reaction to proceed.

[0046] (6) Connect the two flasks in steps (4) and (5) with a double-ended injection needle, and slowly evacuate the flask containing the Cd precursor. Due to the pressure difference, the zinc sulfide-cuprous sulfide particle mixture is injected into the Cd precursor to carry out the reaction for 15 minutes.

[0047] (7) The reaction solution in step (6) was heated, kept warm and cooled with ice water. The temperature was raised to 140°C and kept warm for 5 minutes. Then it was cooled in an ice water bath. A small amount of n-hexane was added to terminate the reaction. Finally, the solution was centrifuged and washed three times and dried to obtain cadmium sulfide-zinc sulfide-cuprous sulfide particles.

[0048] The cadmium sulfide-zinc sulfide-cuprous sulfide single-particle nanoheterostructure material obtained in this embodiment was examined by X-ray diffraction and transmission electron microscopy. The results showed that this embodiment successfully synthesized Cu. 1.94 S like Figure 3 As shown (i.e., the product in Comparative Example 1). For example... Figure 4 As shown, the cuprous sulfide obtained in this embodiment has a hexagonal flake morphology (i.e., the product in Comparative Example 1). This embodiment successfully synthesized cadmium sulfide-zinc sulfide-cuprous sulfide as shown in the figure. Figure 1 As shown, Figure 1 The phases of cadmium sulfide, zinc sulfide, and cuprous sulfide are clearly visible. For example... Figure 2 As shown, from Figure 2 It can be observed that the size of cadmium sulfide-zinc sulfide-cuprous sulfide is almost the same as that of the initial cuprous sulfide, and there are multiple structural domains with different brightness.

[0049] Example 2:

[0050] The preparation method of the cadmium sulfide-zinc sulfide-cuprous sulfide single-particle nano-heterostructure material in this embodiment is the same as that in Example 1, except that the cooling temperature in step (3) is changed to 115°C.

[0051] Example 3:

[0052] The preparation method of the cadmium sulfide-zinc sulfide-cuprous sulfide single-particle nano-heterostructure material in this embodiment is the same as that in Example 1, except that the heating-heating-ice water cooling treatment in step (7) is not performed.

[0053] Example 4:

[0054] The preparation method of the cadmium sulfide-zinc sulfide-cuprous sulfide single-particle nanoheterostructure material in this embodiment is the same as that in Example 1, except that the amount of zinc chloride, octadecene and oleylamine added in step (3) is changed to 0.4 mmol, 48 mmol and 38.7 mmol respectively, and the amount of cadmium chloride, octadecene and oleylamine added in step (5) is changed to 0.2 mmol, 24 mmol and 19.3 mmol respectively.

[0055] Comparative Example 1:

[0056] A method for preparing cuprous sulfide sheet-like nanoparticles includes the following steps:

[0057] (1) Add 20 mmol of oleylamine and 4 mmol of anhydrous copper chloride to a 100 mL round-bottom flask, seal it, stir it magnetically, evacuate it three times and introduce inert gas, then heat it to 80 °C and keep it at that temperature for 15 min; add 48 mmol of tert-dodecyl mercaptan to another flask, seal it, evacuate it three times at room temperature and introduce inert gas, then heat it to 80 °C.

[0058] (2) Connect the two flasks in step (1) with a double-ended injection needle, and introduce a small amount of argon gas into the flask containing tert-dodecyl mercaptan. Due to the pressure difference, tert-dodecyl mercaptan is injected into the flask containing copper chloride. Remove the injection needle, heat the solution to 180°C and react for 30 min. Finally, cool it to 15°C in an ice-water bath, wash and dry to obtain cuprous sulfide nanoparticles.

[0059] Comparative Example 2:

[0060] A method for preparing cadmium sulfide-cuprous sulfide particles includes the following steps:

[0061] (1) Add 20 mmol of oleylamine and 4 mmol of anhydrous copper chloride to a 100 mL round-bottom flask, seal it, stir it magnetically, and evacuate it three times at room temperature while introducing inert gas; then heat it to 80 °C and keep it at that temperature for 15 min; add 48 mmol of tert-dodecyl mercaptan to another flask, seal it, and evacuate it three times at room temperature while introducing inert gas, and then heat it to 80 °C.

[0062] (2) Connect the two flasks in step (1) with a double-ended injection needle, and introduce a small amount of argon gas into the flask containing tert-dodecyl mercaptan. Due to the pressure difference, tert-dodecyl mercaptan is injected into the flask containing copper chloride. Remove the injection needle, heat the solution to 180°C and react for 30 min. Finally, cool it to 15°C in an ice-water bath, wash and dry to obtain cuprous sulfide nanoparticles.

[0063] (3) Add 24 mmol octadecene, 20 mmol oleylamine and 0.2 mmol cadmium chloride to a 100 mL round bottom flask, mix and seal, start magnetic stirring, perform three vacuuming operations and then introduce inert gas; then heat to 200 °C and keep warm for 15 min to obtain the Cd precursor, and then slowly cool to 85 °C to wait for the reaction.

[0064] (4) 0.6 mmol cuprous sulfide particles were ultrasonically dispersed in 4 mmol octadecene and injected together with 5 mmol tri-n-octylphosphine into the Cd precursor. The reaction was carried out for 30 min, and finally cooled in an ice-water bath, centrifuged and washed three times, and dried to obtain cadmium sulfide-cuprous sulfide particles.

[0065] The products obtained in Examples 1-4 and Comparative Examples 1-2 were subjected to photocatalytic hydrogen production. Specific test methods and conditions were as follows:

[0066] Using a 300W xenon lamp as the light source (combined with AM 1.5G), 20 mg of the product was dispersed in 100 mL of water containing 0.1 mol / L Na₂SO₃ and 0.1 mol / L Na₂S, and sealed. The reactor temperature was controlled at 10°C, and illumination was initiated. The amount of hydrogen in the reactor was measured every half hour. The CdS-ZnS-Cu obtained in Example 1 was determined. 2-x The photocatalytic hydrogen evolution efficiency of the S heterojunction photocatalyst is 3.01 mmol·g. -1 ·h -1 Furthermore, no significant attenuation was observed within 24 hours. The CdS-ZnS-Cu obtained in Example 2... 2-x The photocatalytic hydrogen evolution efficiency of the S heterojunction photocatalyst is 2.50 mmol·g. -1 ·h -1 Furthermore, no significant attenuation was observed within 24 hours. The CdS-ZnS-Cu obtained in Example 3... 2-x The photocatalytic hydrogen evolution efficiency of the S heterojunction photocatalyst is 2.85 mmol·g. -1 ·h -1 However, it decayed to 80% of its initial value after 6 hours. The CdS-ZnS-Cu obtained in Example 4... 2-x The photocatalytic hydrogen evolution efficiency of the S heterojunction photocatalyst is 2.37 mmol·g. -1 ·h -1 The Cu obtained in Comparative Example 1 2-x The hydrogen evolution rate of S is 0, and the CdS-Cu obtained in Comparative Example 2 is 0. 2-x The hydrogen evolution amount of S is 0.013 mmol·g -1 ·h -1 Furthermore, it decayed to 60% of its initial value after 6 hours. Compared to Comparative Examples 1 and 2, the CdS-ZnS-Cu prepared in this invention... 2-x The hydrogen evolution efficiency and stability of the S single-particle nano-heterojunction photocatalyst are significantly improved, thus realizing the preparation and application of multi-component complex nano-heterojunctions.

Claims

1. A cadmium sulfide-zinc sulfide-cuprous sulfide Cu 1.94 The method for preparing S-nano heterojunction materials is characterized by... Includes the following steps: (1) Add oleylamine and copper chloride to the first container and seal it, stir, evacuate, and heat it; add tert-dodecyl mercaptan to the second container and evacuate, and heat it. (2) connecting the first container and the second container with a pipeline and introducing inert gas into the second container, due to the pressure difference, the tertiary dodecyl mercaptan is injected into the first container, the solution in the first container is warmed and reacted, and finally cooled, washed, and dried to obtain cuprous sulfide Cu 1.94 S nanoparticles; (3) In the third container, octadecene, oleylamine and zinc chloride are mixed and sealed, stirred, evacuated and then inert gas is introduced and heated to react to obtain the precursor of Zn; (4) The cuprous sulfide CuS obtained in step (2) is added to the solution of zinc sulfate ZnS04obtained in step (3) to obtain a mixture, and then the mixture is heated to 60°C to obtain a solution of ZnS and CuS. 1.94 S nanoparticles are ultrasonically dispersed in octadecene to obtain a dispersion liquid, the dispersion liquid and tri-n-octylphosphine are added to the precursor of Zn obtained in step (3) to carry out a reaction, and zinc sulfide-cuprous sulfide CuS is obtained. 1.94 S particle mixture liquid; (5) In the fourth container, octadecene, oleylamine and cadmium chloride are mixed and sealed, stirred, vacuumed and heated to react to obtain the precursor of Cd; (6) Connect the third and fourth containers with a pipe. Due to the pressure difference, zinc sulfide-cuprous sulfide Cu 1.94 The S-particle mixture was injected into the fourth container to carry out the reaction; (7) The reaction was terminated by injecting a reaction terminator into the fourth container. Finally, the container was washed and dried to obtain cadmium sulfide-zinc sulfide-cuprous sulfide Cu. 1.94 S-nano heterojunction materials; Before injecting the reaction terminator into the fourth container to terminate the reaction, the solution in the fourth container is first subjected to a heating-holding-ice water cooling treatment, and then n-hexane is injected to terminate the reaction. The heating-holding-ice water cooling treatment is to heat the solution in the fourth container to 140-150℃, hold it for 5-10 minutes, and then quickly cool it with ice water.

2. The preparation method according to claim 1, characterized in that, In step (1), the molar ratio of oleylamine to copper chloride is (20-25):(2-4), and the molar ratio of copper chloride to tert-dodecyl mercaptan is 1:(3-24); the solutions in the first and second containers are heated to 80-90℃ and then kept at that temperature for 30-40 minutes.

3. The preparation method according to claim 1, characterized in that, In step (2), during the heating reaction, the temperature is raised to 160-190℃ and reacted for 15-30 minutes, and then cooled to 15-50℃.

4. The preparation method according to claim 1, characterized in that, In step (3), the molar ratio of octadecene, oleylamine and zinc chloride is (120-130):(95-105):1; when heating the reaction, the temperature is raised to 160-190℃ and reacted for 15-30 minutes, then cooled to 85-115℃ and kept warm.

5. The preparation method according to claim 1, characterized in that, In step (4), the cuprous sulfide Cu added to the Zn precursor 1.94 The molar ratio of S nanoparticles to tri-n-octylphosphine is 1:(7-12), and the molar ratio of cuprous sulfide Cu is... 1.94 The amount of S nanoparticles added controls the amount of cuprous sulfide Cu. 1.94 The molar ratio of S nanoparticles to zinc chloride is (0.9-1.2):(0.3-0.5), and the reaction time after addition is 30-60 min.

6. The preparation method according to claim 1, characterized in that, In step (5), the molar ratio of octadecene, oleylamine and cadmium chloride is (120-130):(95-105):1; when heating the reaction, the temperature is raised to 180-210℃ and reacted for 15-30 minutes, then cooled to 50-85℃ and kept warm.

7. The preparation method according to claim 1, characterized in that, In step (6), zinc sulfide-cuprous sulfide Cu 1.94 The amount of S-particle mixture added is controlled by zinc sulfide-cuprous sulfide Cu. 1.94 The molar ratio of S particles to cadmium chloride is (0.9-1.2):(0.2-0.3), and the reaction time after addition is 15-30 min.

8. A cadmium sulfide-zinc sulfide-cuprous sulfide Cu prepared by any one of claims 1-7 1.94 S-nano heterojunction material.

9. A cadmium sulfide-zinc sulfide-cuprous sulfide Cu as described in claim 8 1.94 Application of S-nano heterojunction materials in photocatalytic hydrogen evolution catalysts.

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