ZIF-8-derived three-phase selenide heterogeneous powder and preparation method thereof

Abstract

The invention discloses a preparation method of ZIF-8-derived three-phase selenide heterogeneous powder, which specifically comprises the following steps: preparing a uniform mixed solvent M and uniformly dispersed transparent solutions A and B, mixing the transparent solutions A and B to obtain a turbid liquid C, carrying out low-temperature centrifugal drying on the turbid liquid C, and carrying out high-temperature calcination to obtain the ZIF-8-derived three-phase selenide heterogeneous powder. The invention also discloses the heterogeneous powder prepared by the method, and the final structure is directly synthesized by adopting a room-temperature coprecipitation method and a high-temperature calcination method, so that the heterogeneous powder has the advantages of high crystallinity, simple synthesis path and no need of large instruments and harsh reaction conditions; when the heterogeneous powder prepared by the method is used as a lithium-sulfur battery positive electrode carrier material, relatively excellent electrochemical performance and catalytic performance can be shown.

Description

Technical Field

[0001] This invention belongs to the field of three-phase selenide heteromaterial technology, specifically relating to a method for preparing ZIF-8 derived three-phase selenide heteropowder, and also to the heteropowder prepared by this method. Background Technology

[0002] Lithium-sulfur batteries are considered the next generation of energy storage systems due to their high theoretical capacity, but their practical application faces severe challenges due to the insulation properties of the sulfur cathode and the polysulfide shuttle effect. Traditional single-phase metal selenides (such as ZnSe and CoSe2) can provide chemisorption or catalytic activity, but a single component cannot simultaneously meet the requirements of strong adsorption, fast conversion, and high conductivity. Two-phase heterojunctions (such as ZnSe@CoSe2) can improve charge transfer efficiency through the built-in electric field at the interface (Xu, g, et al. "Heterostructure ZnSe-CoSe2 embedded with yolk-shell conductive dodecahedral as Two-in-one hosts for cathode and anode protection of Lithium–Sulfur fullbatteries." Energy Storage Materials 47 (2022): 223-234.), but their synergistic effect is still limited by the number of active sites and the depth of interface modulation. In contrast, ZIF-8-derived three-phase selenide heteropowders achieve a triple breakthrough through precise coupling of multiple components and multiple interfaces. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing ZIF-8 derived three-phase selenide heteropowder, which solves the problems of low conductivity and severe shuttle effect of sulfur cathode in the prior art.

[0004] Another objective of this invention is to provide a highly efficient and controllable method for preparing silicon-carbon anode materials coated with atomic-level interfacial films.

[0005] Another object of the present invention is to provide a method for preparing heterogeneous powders of ZIF-8 derived three-phase selenide heterogeneous powders.

[0006] The technical solution adopted in this invention is a method for preparing ZIF-8 derived three-phase selenide heterogeneous powder, specifically: preparing a uniform mixed solvent M and uniformly dispersed transparent solutions A and B, mixing transparent solutions A and B to obtain suspension C, and centrifuging and drying suspension C at low temperature followed by high temperature calcination to obtain the powder.

[0007] The invention is further characterized in that, The specific steps are as follows: Step 1: Slowly add N,N-dimethylformamide to deionized water and stir magnetically to obtain a homogeneous mixed solvent M; Step 2: Weigh 0.393g~0.409g of vanadium acetylacetonate, 0.447g~0.466g of cobalt nitrate hexahydrate and 1.785g~1.859g of zinc nitrate hexahydrate and add them sequentially to 240ml~250ml of mixed solvent M. Stir magnetically for 20min~30min to obtain a uniformly dispersed transparent solution A. Weigh 1.970g~2.052g of 2-methylimidazole and add it to 240ml~250ml of mixed solvent M. Stir magnetically for 20~30min to obtain a uniformly dispersed transparent solution B. Step 3: Slowly pour solution B into solution A and stir magnetically for 30 to 50 minutes to obtain suspension C. Place suspension C in a cool place and let it stand for 24 to 30 hours. Step 4: Centrifuge the suspended liquid C at low temperature and high speed for 2 min to 5 min at a speed of 7000 r / min to 10000 r / min. After washing with mixed solvent M 3 to 5 times, collect the product and place it in a vacuum drying oven for drying. After vacuum drying at 60℃ to 80℃ for 12 h to 20 h, collect the product to obtain VCoZn-ZIF-8 powder. Step 5: Weigh 0.1g~0.5g of VCoZn-ZIF-8 powder and 0.2g~1.0g of elemental Se, and place them on both sides of a magnetic boat. Then place the magnetic boat in a tube furnace and calcine it in an inert atmosphere to obtain ZIF-8 derived three-phase selenide heteropowder ZnSe@VSe2@CoSe2 / NC.

[0008] In step 1, the volumes of N,N-dimethylformamide and deionized water are both 240ml~250ml, and the magnetic stirring time is 10min~20min.

[0009] In step 2, the molar ratio of vanadium acetylacetonate, cobalt nitrate hexahydrate, and zinc nitrate hexahydrate is 1:1:4.

[0010] In step 3, the suspension C should be sealed with plastic wrap during the standing process.

[0011] In step 4, the cleaned product needs to be sealed with plastic film, then the plastic film is perforated, and finally it is placed in a vacuum drying oven for drying.

[0012] In step 5, the calcination conditions are: heating rate 2℃ / s ~ 4℃ / s, reaction temperature 400℃ ~ 450℃, and reaction time 100min ~ 120min.

[0013] In step 5, the mass ratio of elemental Se to VCoZn-ZIF-8 is 2:1.

[0014] Another technical solution adopted in this invention is to prepare heterogeneous powder using a method for preparing ZIF-8 derived three-phase selenide heterogeneous powder. The heterogeneous powder is a structure composed of uniform polyhedral particles with a diameter of 400 nm stacked together.

[0015] The beneficial effects of this invention are: 1) Compared to doping with vanadium and cobalt sources after synthesizing ZIF-8 particles, this invention uses a co-precipitation method to introduce V / Mn and Co elements in situ into ZIF-8, resulting in a more uniform element distribution; 2) The final structure is directly synthesized by room temperature co-precipitation and high temperature calcination, which has the advantages of high crystallinity, simple synthesis route, no need for large-scale instruments and harsh reaction conditions; 3) Vanadyl acetylacetonate is used as the vanadium source, manganese sulfate monohydrate as the manganese source, cobalt nitrate hexahydrate as the cobalt source, and zinc nitrate hexahydrate as the zinc source. The solvents are water and N,N-dimethylformamide (DMF). These substances are common raw materials, inexpensive and readily available, and have low cost. The overall reaction yield is high, the operation is simple and environmentally friendly, and no post-processing is required, making it suitable for large-scale production. 4) When the heterogeneous powder prepared by this invention is used as a positive electrode support material for lithium-sulfur batteries, it can exhibit relatively excellent electrochemical and catalytic performance. Attached Figure Description

[0016] Figure 1 This is the X-ray diffraction pattern of the product prepared in Example 1 of the present invention; Figure 2 These are scanning electron microscope images of Example 1 of the present invention and the prepared product; Figure 3 This is a high-resolution transmission electron microscope image of the product prepared in Example 1 of the present invention; Figure 4 This is the X-ray diffraction pattern of the product prepared in Example 2 of this invention; Figure 5 This is a high-resolution transmission electron microscope image of the product prepared in Example 2 of the present invention. Detailed Implementation

[0017] The present invention will now be described in detail with reference to specific embodiments and accompanying drawings.

[0018] The method for preparing ZIF-8 derived three-phase selenide heteropowder of the present invention is specifically implemented according to the following steps: The specific steps are as follows: Step 1: Take 240ml~250ml of N,N-dimethylformamide and slowly add it to 240ml~250ml of deionized water. Stir magnetically for 10min~20min to obtain a homogeneous mixed solvent M. Step 2: Weigh 0.393g~0.409g of vanadium acetylacetonate, 0.447g~0.466g of cobalt nitrate hexahydrate and 1.785g~1.859g of zinc nitrate hexahydrate and add them sequentially to 240ml~250ml of mixed solvent M. Stir magnetically for 20min~30min to obtain a uniformly dispersed transparent solution A. Weigh 1.970g~2.052g of 2-methylimidazole and add it to 240ml~250ml of mixed solvent M. Stir magnetically for 20~30min to obtain a uniformly dispersed transparent solution B. In step 2, the molar ratio of vanadium acetylacetonate, cobalt nitrate hexahydrate, and zinc nitrate hexahydrate is 1:1:4, and the ratio should not fluctuate by more than 0.5. This is because excess Zn may not be fully coordinated, resulting in impurity phases such as Zn(OH)2 or ZnO. If the Zn ratio is much lower than 4, it may lead to insufficient coordination sites for Zn, resulting in the formation of some impurity phases rather than a homogeneous three-phase selenide heterogeneous powder. In step 2, replacing 0.393g~0.409g of vanadium acetylacetonate with 0.254g~0.265g of manganese sulfate monohydrate will yield MnCoZn-ZIF-8 powder. Step 3: Slowly pour solution B into solution A and stir magnetically for 30 to 50 minutes to obtain suspension C. Place suspension C in a cool place and let it stand for 24 to 30 hours. In step 3, the suspension C should be sealed with plastic wrap during the standing process; Step 4: Centrifuge the suspended liquid C at low temperature and high speed for 2 min to 5 min at a speed of 7000 r / min to 10000 r / min. After washing with mixed solvent M 3 to 5 times, collect the product and place it in a vacuum drying oven for drying. After vacuum drying at 60℃ to 80℃ for 12 h to 20 h, collect the product to obtain VCoZn-ZIF-8 powder. In step 4, the cleaned product needs to be sealed with plastic film, then the plastic film is perforated, and finally it is placed in a vacuum drying oven for drying. Step 5: Weigh 0.1g~0.5g of VCoZn-ZIF-8 powder and 0.2g~1.0g of elemental Se, and place them on both sides of a magnetic boat. Then place the magnetic boat in a tube furnace and calcine it in an inert atmosphere to obtain ZIF-8 derived three-phase selenide heteropowder ZnSe@VSe2@CoSe2 / NC. In step 5, the calcination conditions are: heating rate 2℃ / s ~ 4℃ / s, reaction temperature 400℃ ~ 450℃, and reaction time 100min ~ 120min; The mass ratio of elemental Se to VCoZn-ZIF-8 is 2:1.

[0019] Example 1 The preparation method of ZIF-8 derived three-phase selenide heteropowder is carried out according to the following steps: Step 1: Measure 240 ml of N,N-dimethylformamide (DMF) and slowly add it to 240 ml of deionized water. Stir magnetically for 10 min to obtain a homogeneous mixed solvent M. Step 2: Weigh 0.393g of vanadium acetylacetonate, 0.447g of cobalt nitrate hexahydrate and 1.785g of zinc nitrate hexahydrate and add them sequentially to 240ml of mixed solvent M. Stir magnetically for 20 min to obtain a uniformly dispersed transparent solution A. Weigh 1.970g of 2-methylimidazole and add it to 240ml of mixed solvent M. Stir magnetically for 20 min to obtain a uniformly dispersed transparent solution B. Step 3: Slowly pour solution B into solution A, stir magnetically for 30 minutes to obtain suspension C, and place suspension C in a cool place to stand for 24 hours; Step 4: The suspension C after standing is centrifuged at low temperature and high speed for 3 minutes at 9000 r / min. After washing with mixed solvent M 5 times, the product is collected and placed in a vacuum drying oven for drying. After vacuum drying at 60 ℃ for 12 h, the product is collected to obtain VCoZn-ZIF-8 powder. Step 5: Weigh 0.3 g of CoZn-ZIF-8 powder and 0.6 g of elemental Se, and place them on both sides of a magnetic boat. Then, place the magnetic boat in a tube furnace and calcine it at 450 °C for 120 min in an inert atmosphere to obtain the ZIF-8 derived three-phase selenide heteropowder ZnSe@VSe2@CoSe2 / NC. Its X-ray diffraction pattern, scanning electron microscope image, and high-resolution transmission electron microscope image are shown below. Figure 1-3 As shown.

[0020] Example 2 The preparation method of ZIF-8 derived three-phase selenide heteropowder is carried out according to the following steps: Step 1: Measure 240 ml of N,N-dimethylformamide (DMF) and slowly add it to 240 ml of deionized water. Stir magnetically for 10 min to obtain a homogeneous mixed solvent M. Step 2: Weigh 0.254 g manganese sulfate monohydrate, 0.447 g cobalt nitrate hexahydrate and 1.785 g zinc nitrate hexahydrate and add them sequentially to 240 ml of mixed solvent M. Stir magnetically for 20 min to obtain a uniformly dispersed transparent solution A. Weigh 1.970 g of 2-methylimidazole and add it to 240 ml of mixed solvent M. Stir magnetically for 20 min to obtain a uniformly dispersed transparent solution B. Step 3: Slowly pour solution B into solution A, stir magnetically for 30 min to obtain suspension C, and place suspension C in a cool place to stand for 24 h; Step 4: The suspension C after standing is centrifuged at low temperature and high speed for 3 minutes at 9000 r / min. After washing with mixed solvent M 5 times, the product is collected and placed in a vacuum drying oven for drying. After vacuum drying at 60 ℃ for 12 h, the product is collected to obtain MnCoZn-ZIF-8 powder. Step 5: Weigh 0.3 g of MnCoZn-ZIF-8 powder and 0.6 g of elemental Se, and place them on opposite sides of a magnetic boat. Then, place the magnetic boat in a tube furnace and calcine it at 450 ℃ for 120 min under an inert atmosphere to obtain the ZIF-8 derived three-phase selenide heteropowder ZnSe@CoSe2@MnSe / NC. Its X-ray diffraction pattern and high-resolution transmission electron microscopy image are shown below. Figure 4-5 As shown.

[0021] Example 3 The preparation method of ZIF-8 derived three-phase selenide heteropowder is carried out according to the following steps: Step 1: Measure 250 ml of N,N-dimethylformamide (DMF) and slowly add it to 250 ml of deionized water. Stir magnetically for 20 min to obtain a homogeneous mixed solvent M. Step 2: Weigh 0.409g of vanadium acetylacetonate, 0.466g of cobalt nitrate hexahydrate and 1.859g of zinc nitrate hexahydrate and add them sequentially to 250ml of mixed solvent M. Stir magnetically for 30 min to obtain a uniformly dispersed transparent solution A. Weigh 2.052g of 2-methylimidazole and add it to 250ml of mixed solvent M. Stir magnetically for 30 min to obtain a uniformly dispersed transparent solution B. Step 3: Slowly pour solution B into solution A, stir magnetically for 50 minutes to obtain suspension C, and place suspension C in a cool place to stand for 30 hours; Step 4: The suspension C after standing is centrifuged at low temperature and high speed for 5 minutes at 7000 r / min. After washing with mixed solvent M three times, the product is collected and placed in a vacuum drying oven for drying. After vacuum drying at 80 °C for 20 h, the product is collected to obtain VCoZn-ZIF-8 powder. Step 5: Weigh 0.1g of VCoZn-ZIF-8 powder and 0.2g of elemental Se, and place them on both sides of a magnetic boat. Then place the magnetic boat into a tube furnace and calcine it at 400 ℃ for 100 min in an inert atmosphere to obtain ZIF-8 derived three-phase selenide heteropowder ZnSe@VSe2@CoSe2 / NC.

[0022] Example 4 The preparation method of ZIF-8 derived three-phase selenide heteropowder is carried out according to the following steps: Step 1: Measure 245 ml of N,N-dimethylformamide (DMF) and slowly add it to 245 ml of deionized water. Stir magnetically for 15 min to obtain a homogeneous mixed solvent M. Step 2: Weigh 0.400g of vanadium acetylacetonate, 0.456g of cobalt nitrate hexahydrate and 1.800g of zinc nitrate hexahydrate and add them sequentially to 245ml of mixed solvent M. Stir magnetically for 25 min to obtain a uniformly dispersed transparent solution A. Weigh 2.000g of 2-methylimidazole and add it to 245ml of mixed solvent M. Stir magnetically for 25 min to obtain a uniformly dispersed transparent solution B. Step 3: Slowly pour solution B into solution A, stir magnetically for 40 minutes to obtain suspension C, and place suspension C in a cool place to stand for 26 hours; Step 4: The suspension C after standing is centrifuged at low temperature and high speed for 3 minutes at 10000 r / min. After washing with mixed solvent M 4 times, the product is collected and placed in a vacuum drying oven for drying. After vacuum drying at 70 ℃ for 16 h, the product is collected to obtain VCoZn-ZIF-8 powder. Step 5: Weigh 0.4g of VCoZn-ZIF-8 powder and 0.8g of elemental Se, and place them on both sides of a magnetic boat. Then place the magnetic boat into a tube furnace and calcine it at 420 ℃ for 110 min in an inert atmosphere to obtain ZIF-8 derived three-phase selenide heteropowder ZnSe@VSe2@CoSe2 / NC.

[0023] Example 5 The preparation method of ZIF-8 derived three-phase selenide heteropowder is carried out according to the following steps: Step 1: Measure 250 ml of N,N-dimethylformamide (DMF) and slowly add it to 250 ml of deionized water. Stir magnetically for 20 min to obtain a homogeneous mixed solvent M. Step 2: Weigh 0.409g of vanadium acetylacetonate, 0.466g of cobalt nitrate hexahydrate and 1.859g of zinc nitrate hexahydrate and add them sequentially to 250ml of mixed solvent M. Stir magnetically for 30 min to obtain a uniformly dispersed transparent solution A. Weigh 2.052g of 2-methylimidazole and add it to 250ml of mixed solvent M. Stir magnetically for 30 min to obtain a uniformly dispersed transparent solution B. Step 3: Slowly pour solution B into solution A, stir magnetically for 50 minutes to obtain suspension C, and place suspension C in a cool place to stand for 30 hours; Step 4: The suspension C after standing is centrifuged at low temperature and high speed for 3 minutes at 10000 r / min. After washing with mixed solvent M 4 times, the product is collected and placed in a vacuum drying oven for drying. After vacuum drying at 70 ℃ for 16 h, the product is collected to obtain VCoZn-ZIF-8 powder. Step 5: Weigh 0.4g of VCoZn-ZIF-8 powder and 0.8g of elemental Se, and place them on both sides of a magnetic boat. Then place the magnetic boat into a tube furnace and calcine it at 420 ℃ for 110 min in an inert atmosphere to obtain ZIF-8 derived three-phase selenide heteropowder ZnSe@VSe2@CoSe2 / NC.

[0024] Example 6 The preparation method of ZIF-8 derived three-phase selenide heteropowder is carried out according to the following steps: Step 1: Measure 245 ml of N,N-dimethylformamide (DMF) and slowly add it to 245 ml of deionized water. Stir magnetically for 15 min to obtain a homogeneous mixed solvent M. Step 2: Weigh 0.400g of vanadium acetylacetonate, 0.456g of cobalt nitrate hexahydrate and 1.800g of zinc nitrate hexahydrate and add them sequentially to 245ml of mixed solvent M. Stir magnetically for 25 min to obtain a uniformly dispersed transparent solution A. Weigh 2.000g of 2-methylimidazole and add it to 245ml of mixed solvent M. Stir magnetically for 25 min to obtain a uniformly dispersed transparent solution B. Step 3: Slowly pour solution B into solution A, stir magnetically for 40 minutes to obtain suspension C, and place suspension C in a cool place to stand for 26 hours; Step 4: The suspension C after standing is centrifuged at low temperature and high speed for 5 minutes at 7000 r / min. After washing with mixed solvent M three times, the product is collected and placed in a vacuum drying oven for drying. After vacuum drying at 80 °C for 20 h, the product is collected to obtain VCoZn-ZIF-8 powder. Step 5: Weigh 0.1g of VCoZn-ZIF-8 powder and 0.2g of elemental Se, and place them on both sides of a magnetic boat. Then place the magnetic boat into a tube furnace and calcine it at 400 ℃ for 100 min in an inert atmosphere to obtain ZIF-8 derived three-phase selenide heteropowder ZnSe@VSe2@CoSe2 / NC.

[0025] like Figure 1 , 4 As shown, all diffraction peaks of the ZnSe@VSe2@CoSe2 / NC sample match well with ZnSe (PDF#37-1463), CoSe2 (PDF#53-1449), and VSe2 (PDF#89-1641); all diffraction peaks of the ZnSe@CoSe2@MnSe / NC sample match well with ZnSe (PDF#77-2100), CoSe2 (PDF#53-1449), and MnSe (PDF#11-0683).

[0026] like Figure 2 As shown, ZnSe@VSe2@CoSe2 / NC exhibits a uniform and regular dodecahedral morphology with uniform particle size and a particle diameter of approximately 400 nm.

[0027] like Figure 3 , 5 As shown, in the HRTEM images of ZnSe@VSe2@CoSe2 / NC, the (111) facet (0.32 nm) of ZnSe, the (211) facet (0.19 nm) of CoSe2, and the (211) facet (0.26 nm) of VSe2 were detected, and heterogeneous lattice interfaces with atomic-level contacts were observed. In the HRTEM images of ZnSe@CoSe2@MnSe / NC, the (220) facet (0.20 nm) of ZnSe, the (111) facet (0.26 nm) of CoSe2, and the (200) facet (0.28 nm) of MnSe2 were detected, and heterogeneous lattice interfaces with atomic-level contacts were observed. This indicates the successful synthesis of three-phase selenides on an N-doped C matrix with good contact.

[0028] Compared to doping ZIF-8 particles with vanadium and cobalt sources after synthesis, the innovation of this invention lies in the in-situ introduction of V / Mn and Co elements into ZIF-8 via a co-precipitation method, resulting in a more uniform element distribution. This invention, employing a room-temperature co-precipitation method followed by high-temperature calcination to directly synthesize the final structure, offers advantages such as high crystallinity, a simple synthesis route, and the elimination of the need for large-scale equipment and harsh reaction conditions. This invention uses vanadium acetylacetonate as the vanadium source, manganese sulfate monohydrate as the manganese source, cobalt nitrate hexahydrate as the cobalt source, and zinc nitrate hexahydrate as the zinc source. The solvents are water and N,N-dimethylformamide (DMF). These substances are common, inexpensive, and readily available raw materials with low cost. The overall reaction yield is high, the operation is simple and environmentally friendly, requires no post-processing, and is suitable for large-scale production. When the product prepared by this invention is used as a positive electrode carrier material for lithium-sulfur batteries, it exhibits excellent electrochemical and catalytic performance.

Claims

1. A method for preparing ZIF-8 derived three-phase selenide heterogeneous powder, characterized in that, Specifically, a uniform mixed solvent M and uniformly dispersed transparent solutions A and B are prepared. After mixing transparent solutions A and B, a suspension C is obtained. The suspension C is then centrifuged and dried at low temperature and calcined at high temperature to obtain the final product.

2. The method for preparing ZIF-8 derived three-phase selenide heteropowder according to claim 1, characterized in that, The specific steps are as follows: Step 1: Slowly add N,N-dimethylformamide to deionized water and stir magnetically to obtain a homogeneous mixed solvent M; Step 2: Weigh 0.393g~0.409g of vanadium acetylacetonate, 0.447g~0.466g of cobalt nitrate hexahydrate and 1.785g~1.859g of zinc nitrate hexahydrate and add them sequentially to 240ml~250ml of mixed solvent M. Stir magnetically for 20min~30min to obtain a uniformly dispersed transparent solution A. Weigh 1.970g~2.052g of 2-methylimidazole and add it to 240ml~250ml of mixed solvent M. Stir magnetically for 20~30min to obtain a uniformly dispersed transparent solution B. Step 3: Slowly pour solution B into solution A and stir magnetically for 30 to 50 minutes to obtain suspension C. Place suspension C in a cool place and let it stand for 24 to 30 hours. Step 4: Centrifuge the suspended liquid C at low temperature and high speed for 2 min to 5 min at a speed of 7000 r / min to 10000 r / min. After washing with mixed solvent M 3 to 5 times, collect the product and place it in a vacuum drying oven for drying. After vacuum drying at 60℃ to 80℃ for 12 h to 20 h, collect the product to obtain VCoZn-ZIF-8 powder. Step 5: Weigh 0.1g~0.5g of VCoZn-ZIF-8 powder and 0.2g~1.0g of elemental Se, and place them on both sides of a magnetic boat. Then place the magnetic boat into a tube furnace and calcine it in an inert atmosphere to obtain ZIF-8 derived three-phase selenide heteropowder.

3. The method for preparing ZIF-8 derived three-phase selenide heteropowder according to claim 2, characterized in that, In step 1, the volumes of N,N-dimethylformamide and deionized water are both 240ml~250ml, and the magnetic stirring time is 10min~20min.

4. The method for preparing ZIF-8 derived three-phase selenide heteropowder according to claim 2, characterized in that, In step 2, the molar ratio of vanadium acetylacetonate, cobalt nitrate hexahydrate, and zinc nitrate hexahydrate is 1:1:

4.

5. The method for preparing ZIF-8 derived three-phase selenide heteropowder according to claim 2, characterized in that, In step 3, the suspension C should be sealed with plastic wrap during the standing process.

6. The method for preparing ZIF-8 derived three-phase selenide heteropowder according to claim 2, characterized in that, In step 4, the cleaned product needs to be sealed with a plastic film, then the plastic film is perforated, and finally it is placed in a vacuum drying oven for drying.

7. The method for preparing ZIF-8 derived three-phase selenide heteropowder according to claim 2, characterized in that, In step 5, the calcination conditions are: heating rate of 2℃ / s ~ 4℃ / s, reaction temperature of 400℃ ~ 450℃, and reaction time of 100min ~ 120min.

8. The method for preparing ZIF-8 derived three-phase selenide heteropowder according to claim 2, characterized in that, In step 5, the mass ratio of elemental Se to VCoZn-ZIF-8 is 2:

1.

9. The heterogeneous powder prepared by the method for preparing ZIF-8 derived three-phase selenide heterogeneous powder according to any one of claims 1-8, characterized in that, The heterogeneous powder is a structure composed of stacked uniform polyhedral particles with a diameter of 400 nm.

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