Hydrogen and oxygen evolution difunctional water electrolysis catalyst, preparation method thereof and water electrolysis device

Abstract

The invention provides a hydrogen and oxygen evolution difunctional water electrolysis catalyst, a preparation method thereof and a water electrolysis device, and relates to the field of water electrolysis catalysts. The hydrogen and oxygen evolution bifunctional electrolyzed water catalyst comprises a porous substrate and a main catalytic structure located on the substrate, and the main catalytic structure comprises a topological insulating layer and a Bi2S3 layer which are arranged in a stacked mode. The porous structure of the porous substrate in the catalyst can increase the reaction active area of the composite material, Bi2S3 can improve the stability of the material, the topological insulator material can reduce the carrier recombination efficiency, an electron hole high-speed transmission channel is formed, the carrier separation and transmission efficiency is improved, and the performance of the catalyst is improved. The porous substrate, the topological insulating layer and the Bi2S3 layer are matched with one another, and an efficient catalysis effect is achieved on both an OER reaction and an HER reaction.

Description

Technical Field

[0001] The present application relates to the field of catalysts for water electrolysis, and in particular to a hydrogen and oxygen evolution dual-function water electrolysis catalyst, a preparation method thereof, and a water electrolysis device. Background Art

[0002] Compared with traditional fossil fuels, hydrogen energy has significant advantages such as high combustion calorific value, environmental friendliness, renewable, and wide sources. It is the most promising green energy in recent years. There is no doubt that it will gradually replace fossil fuels and become the mainstay of future energy. At present, electrocatalytic water splitting technology (electrolysis of water) is considered to be one of the simplest hydrogen production technologies. This technology includes oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). In the electrocatalytic water splitting system, the energy efficiency and stability of the reaction are important evaluation indicators for hydrogen and oxygen production by electrolysis of water. The use of catalysts can change the electron transfer path and reaction energy barrier in the electrocatalytic process, thereby effectively reducing the reaction overpotential and improving the conversion efficiency of hydrogen and gas production by electrolysis of water.

[0003] Currently, the most widely used catalysts are mainly Pt-based precious metal catalysts. Precious metal materials have shown excellent performance in the field of electrocatalytic hydrogen production. However, due to the low reserves of precious metals and the fact that they are non-renewable resources, the cost of catalysts remains high, which limits their development and utilization in water electrolysis.

[0004] In recent years, transition metals and their compounds have attracted widespread attention from researchers due to their abundant reserves, low cost, and long-term durability, providing more possibilities for the selection of electrolytic water catalysts. At present, non-precious metal catalysts for electrolytic water have been reported with excellent performance. For example, oxides of transition metals such as iron, cobalt, and nickel are used as efficient oxygen evolution catalysts, while their sulfides, phosphides, nitrides, carbides, etc. are considered to be excellent electrocatalysts for hydrogen evolution reactions. However, there are still great difficulties in using the same catalyst for the catalysis of both hydrogen evolution and oxygen evolution reactions. Moreover, non-precious metal-based transition metal-based catalysts usually have the defect of complex preparation processes, and toxic or dangerous raw materials such as hydrazine hydrate are usually used in the preparation process, which causes certain pollution to the environment and is not conducive to sustainable development. In response to the needs of reducing the cost of electrolytic water and improving the catalytic efficiency, the development of a low-cost, simple preparation process, non-precious metal bifunctional and efficient catalyst is a problem that needs to be solved urgently. Summary of the invention

[0005] The purpose of the present application is to provide a dual-functional water electrolysis catalyst for hydrogen and oxygen evolution, a preparation method thereof, and a water electrolysis device to solve the above-mentioned problems.

[0006] To achieve the above objectives, this application adopts the following technical solutions:

[0007] A hydrogen and oxygen evolution dual-function water electrolysis catalyst comprises: a porous substrate and a main catalytic structure located on the substrate, wherein the main catalytic structure comprises a topological insulating layer and a Bi2S3 layer which are stacked.

[0008] According to an embodiment of the present application, the topological insulating layer is located between the porous substrate and the Bi2S3 layer, or the Bi2S3 layer is located between the porous substrate and the topological insulating layer.

[0009] According to an embodiment of the present application, the porous substrate includes foamed molybdenum nickel.

[0010] According to an embodiment of the present application, the material forming the topological insulating layer includes any one of Bi2Te3, Bi2Se3, and Bi2Se2Te.

[0011] The present application also provides a method for preparing the hydrogen and oxygen evolution bifunctional water electrolysis catalyst as described above, comprising:

[0012] A main catalytic structure is formed on a porous substrate by a solvothermal method to obtain a bifunctional water electrolysis catalyst for hydrogen and oxygen evolution; wherein the main catalytic structure includes a topological insulating layer and a Bi2S3 layer arranged in a stacked manner.

[0013] According to an embodiment of the present application, forming a main catalytic structure on a porous substrate by a solvothermal method comprises:

[0014] The porous substrate, bismuth source, sulfur source and ethylene glycol are mixed, and a first solvent thermal reaction is carried out in a reactor to obtain a composite structure of the porous substrate and Bi2S3;

[0015] The topological insulating material precursor, the composite structure of the porous substrate and Bi2S3 and sodium hydroxide are mixed, and a second solvent thermal reaction is carried out in a reactor to obtain a hydrogen and oxygen evolution bifunctional water electrolysis catalyst.

[0016] According to an embodiment of the present application, the bismuth source includes Bi(NO3)3 or a hydrate of Bi(NO3)3;

[0017] And / or, the sulfur source includes at least one of thioacetamide, sodium sulfide nonahydrate, thiourea, and sodium sulfite;

[0018] And / or, the molar ratio of the bismuth source to the sulfur source is 1:(11-13);

[0019] and / or, the temperature of the first solvent thermal reaction is 170-190° C., and the time of the first solvent thermal reaction is 11-13 h;

[0020] And / or, the topological insulating material precursor comprises Bi2O3 and TeO2, and the molar ratio of Bi2O3 to TeO2 is 1:(2-4);

[0021] and / or, the molar ratio of the bismuth source to the Bi2O3 is 2:(0.9-1.1);

[0022] and / or, the molar ratio of the Bi2O3 to the sodium hydroxide is 1:(18-22);

[0023] And / or, when performing the second solvothermal reaction, the method further comprises adding PVP to the reaction system, wherein the mass ratio of the Bi2O3 to the PVP is 0.233:(0.4-0.6);

[0024] And / or, the temperature of the second solvent thermal reaction is 170-190° C., and the time of the second solvent thermal reaction is 23-25 ​​hours.

[0025] According to an embodiment of the present application, forming a main catalytic structure on a porous substrate by a solvothermal method comprises:

[0026] The porous substrate, the topological insulating material precursor, ethylene glycol and sodium hydroxide are mixed, and a third solvothermal reaction is carried out in a reactor to obtain a composite structure of the porous substrate and the topological insulating material;

[0027] A bismuth source, a sulfur source, a composite structure of a porous substrate and a topological insulating material, and ethylene glycol are mixed, and a fourth solvent thermal reaction is carried out in a reactor to obtain a hydrogen and oxygen evolution bifunctional water electrolysis catalyst.

[0028] According to an embodiment of the present application, the topological insulating material precursor includes Bi2O3 and TeO2, and the molar ratio of the Bi2O3 to the TeO2 is 1:(2-4);

[0029] and / or, the molar ratio of the Bi2O3 to the sodium hydroxide is 1:(18-22);

[0030] And / or, when performing the third solvothermal reaction, the method further comprises adding PVP to the reaction system, wherein the mass ratio of the Bi2O3 to the PVP is 0.233:(0.4-0.6);

[0031] and / or, the temperature of the third solvent thermal reaction is 170-190° C., and the time of the third solvent thermal reaction is 23-25 ​​h;

[0032] and / or, the bismuth source comprises Bi(NO3)3 or a hydrate of Bi(NO3)3;

[0033] And / or, the sulfur source includes at least one of thioacetamide, sodium sulfide nonahydrate, thiourea, and sodium sulfite;

[0034] And / or, the molar ratio of the bismuth source to the sulfur source is 1:(11-13);

[0035] and / or, the molar ratio of the bismuth source to the Bi2O3 is 2:(0.9-1.1);

[0036] And / or, the temperature of the fourth solvent thermal reaction is 170-190° C., and the time of the fourth solvent thermal reaction is 11-13 h.

[0037] The present application also provides a water electrolysis device, which includes the hydrogen and oxygen evolution dual-function water electrolysis catalyst described above.

[0038] Compared with the prior art, the beneficial effects of this application include:

[0039] In the catalyst of the present application, the porous structure of the porous substrate can increase the reactive active area of ​​the composite material, Bi2S3 can improve the material stability, and the topological insulator material can reduce the carrier recombination efficiency and form an electron-hole high-speed transmission channel to improve the separation and transmission efficiency of carriers. The porous substrate, topological insulating layer and Bi2S3 layer of the present application cooperate with each other and have a highly efficient catalytic effect on both OER and HER reactions.

[0040] Moreover, compared with traditional noble metal-based catalysts, the raw materials of the catalyst of the present application are cheap and easy to obtain, the production cost is low, and it is suitable for large-scale production. Compared with commonly used non-noble metal-based transition metal catalysts, the catalyst of the present application has the advantages of simple preparation process, low raw material toxicity, and no pollution to the environment. The topological surface state of the catalyst of the present application can significantly reduce the overpotential of the catalytic reaction and significantly enhance the catalytic performance. At the same time, the composite material can achieve efficient catalysis for both OER and HER reactions in an alkaline environment.

[0041] The present invention only needs two steps of solvothermal method to prepare a high-performance catalyst, the material growth is simple, the production cost is low, and it is expected to achieve large-scale production. The method of the present invention has the advantages of cheap and easy-to-obtain raw materials and simple process. Moreover, the preparation method of the present invention also has the advantage of being green and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope of the present application.

[0043] Figure 1This is a schematic structural diagram of a bifunctional water electrolysis catalyst for hydrogen and oxygen evolution in one embodiment of the present application;

[0044] Figure 2 This is a schematic structural diagram of a bifunctional water electrolysis catalyst for hydrogen and oxygen evolution in another embodiment of the present application;

[0045] Figure 3 XRD pattern of Bi2Te3 prepared in Preparation Example 1;

[0046] Figure 4 This is the SEM image of Bi2Te3 prepared in Preparation Example 1;

[0047] Figure 5 XRD pattern of Bi2S3 prepared in Preparation Example 2;

[0048] Figure 6 This is a SEM image of the cross section of the Bi2Te3-Bi2S3-NMF composite material prepared in Example 1;

[0049] Figure 7 This is a SEM image of the cross section of the Bi2S3-Bi2Te3-NMF composite material prepared in Example 2;

[0050] Figure 8 This is the SEM image of the raw material NMF used in Comparative Example 1;

[0051] Fig. 9 This is the SEM image of Bi2Te3-NMF prepared in Comparative Example 1;

[0052] Fig.10 This is the SEM image of Bi2Te3-NMF prepared in Comparative Example 1;

[0053] Fig.11 It is a comparison diagram of LSV curves of HER reactions of NMF, Examples 1-2 and Comparative Example 1 materials;

[0054] Fig.12 It is a comparison chart of LSV curves of OER reaction of NMF, Examples 1-2 and Comparative Example 1 materials. DETAILED DESCRIPTION

[0055] As used herein:

[0056] "Prepared from" is synonymous with "comprising." As used herein, the terms "comprising," "including," "having," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0057] The conjunction "consisting of excludes any unspecified element, step, or component. If used in a claim, this phrase renders the claim closed-ended so that it does not include materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of" appears in a clause of the body of a claim rather than immediately following the subject matter, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0058] When an amount, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values ​​and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value, regardless of whether the range is disclosed separately. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted as including ranges "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described in this article, unless otherwise stated, the range is intended to include its end values ​​and all integers and fractions within the range.

[0059] In these examples, parts and percentages are by mass unless otherwise indicated.

[0060] "Parts by mass" refers to the basic unit of measurement for expressing the mass ratio of multiple components. 1 part can represent any unit mass, such as 1g or 2.689g. If we say that the mass of component A is a parts and the mass of component B is b parts, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it means that the mass of component A is aK and the mass of component B is bK (K is an arbitrary number, indicating a multiple factor). It should not be misunderstood that, unlike the mass parts, the sum of the mass of all components is not limited to 100 parts.

[0061] "And / or" is used to indicate that one or both of the stated situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0062] The present application provides a hydrogen and oxygen evolution dual-function water electrolysis catalyst, comprising: a porous substrate, and a main catalytic structure located on the substrate, wherein the main catalytic structure comprises a topological insulating layer and a Bi2S3 layer arranged in a stacked manner.

[0063] This application uses a topological insulating layer combined with sulfide to construct a heterostructure as the catalyst body, which can effectively increase the specific surface area, increase the active sites, and improve the catalyst performance. Moreover, the composite of topological insulator material and sulfide improves the stability of the composite material while ensuring that the efficient carrier channel of the topological insulator material is effectively utilized.

[0064] The topological insulating layer can provide high carrier mobility, and Bi2S3 as a buffer interface can ensure the stability of the catalyst. The present application combines the topological insulating layer and the Bi2S3 layer to improve the performance of the catalyst. The catalyst of the present application can not only improve the efficiency of the electrocatalytic reaction and ensure the stability of the composite catalyst, but also realize the dual-function catalysis of HER and OER at the same time, and has good cycle stability.

[0065] The catalyst of the present application can be used not only for HER reaction, but also for OER reaction, catalyzing both HER and OER reactions during the catalytic process. Its main principle is divided into two parts: Bi2S3 mainly acts as a buffer interface to improve the stability of the catalyst, and the topological insulating layer mainly provides a fast carrier migration channel, thereby reducing the internal recombination of carriers in HER and OER reactions and improving the reaction efficiency.

[0066] The difficulty in studying efficient electrocatalytic hydrogen evolution catalysts lies in the preparation of high-quality heterogeneous materials. This application composites topological insulator materials with bismuth sulfide materials on a porous substrate. Through topological surface states, efficient carrier transmission between materials can be guaranteed, which is also the basis for achieving low overpotential in catalytic reactions. The catalyst in this application can maintain high activity of the catalyst while improving hydrogen production efficiency.

[0067] Specifically, Bi2S3 in the catalyst of the present application acts as a buffer interface, which can improve the stability of the material. The porous structure of the porous substrate can increase the reactive area of ​​the composite material. The topological insulator material has the characteristics of rapid movement of surface electrons, which can reduce the efficiency of carrier recombination and form a high-speed electron-hole transmission channel, thereby improving the separation and transmission efficiency of carriers, and finally obtaining a bifunctional water electrolysis catalyst with high catalytic performance.

[0068] According to an embodiment of the present application, the topological insulating layer is located between the porous substrate and the Bi2S3 layer, or the Bi2S3 layer is located between the porous substrate and the topological insulating layer.

[0069] According to an embodiment of the present application, the porous substrate includes foamed molybdenum nickel. The porous structure of the foamed molybdenum nickel can increase the reactive area of ​​the composite material. Compared with traditional materials, the foamed molybdenum nickel substrate used in the present application can increase the surface area of ​​the composite material, increase the catalytic active sites, and efficiently utilize the high carrier migration channels of the topological surface state to improve the catalyst performance.

[0070] According to an embodiment of the present application, the material forming the topological insulating layer includes any one of Bi2Te3, Bi2Se3, and Bi2Se2Te.

[0071] Furthermore, the bifunctional water electrolysis catalyst for hydrogen and oxygen evolution may have Figure 1 or Figure 2 The structure shown.

[0072] The present application also provides a method for preparing the hydrogen and oxygen evolution bifunctional water electrolysis catalyst as described above, comprising:

[0073] A main catalytic structure is formed on a porous substrate by a solvothermal method to obtain a bifunctional water electrolysis catalyst for hydrogen and oxygen evolution; wherein the main catalytic structure includes a topological insulating layer and a Bi2S3 layer arranged in a stacked manner.

[0074] According to an embodiment of the present application, forming a main catalytic structure on a porous substrate by a solvothermal method comprises:

[0075] The porous substrate, bismuth source, sulfur source and ethylene glycol are mixed, and a first solvent thermal reaction is carried out in a reactor to obtain a composite structure of the porous substrate and Bi2S3;

[0076] The topological insulating material precursor, the composite structure of the porous substrate and Bi2S3 and sodium hydroxide are mixed, and a second solvent thermal reaction is carried out in a reactor to obtain a hydrogen and oxygen evolution bifunctional water electrolysis catalyst.

[0077] According to an embodiment of the present application, the bismuth source includes Bi(NO3)3 or a hydrate of Bi(NO3)3;

[0078] And / or, the sulfur source includes at least one of thioacetamide, sodium sulfide nonahydrate, thiourea, and sodium sulfite;

[0079] And / or, the molar ratio of the bismuth source to the sulfur source is 1:(11-13);

[0080] For example, the molar ratio of the bismuth source to the sulfur source may be 1:11, 1:12, 1:12.6, 1:13 or any value in between 1:(11-13).

[0081] and / or, the temperature of the first solvent thermal reaction is 170-190° C., and the time of the first solvent thermal reaction is 11-13 h;

[0082] For example, the temperature of the first solvothermal reaction can be 170°C, 180°C, 190°C or any value between 170-190°C, and the time of the first solvothermal reaction can be 11h, 12h, 13h or any value between 11-13h.

[0083] And / or, the topological insulating material precursor includes Bi2O3 and TeO2, and the molar ratio of Bi2O3 to TeO2 is 1:(2-4); for example, the molar ratio of Bi2O3 to TeO2 can be 1:2, 1:3, 1:4 or any value between 1:(2-4).

[0084] And / or, the molar ratio of the bismuth source to the Bi2O3 is 2:(0.9-1.1); for example, the molar ratio of the bismuth source to Bi2O3 can be any value between 2:0.9, 2:1, 2:1.1 or 2:(0.9-1.1).

[0085] And / or, the molar ratio of Bi2O3 to sodium hydroxide is 1:(18-22); for example, the molar ratio of Bi2O3 to sodium hydroxide can be 1:18, 1:19, 1:20, 1:21, 1:22 or any value between 1:(18-22).

[0086] And / or, when performing the second solvent thermal reaction, the method also includes adding PVP to the reaction system, and the mass ratio of Bi2O3 to PVP is 0.233:(0.4-0.6); for example, the mass ratio of Bi2O3 to PVP can be 0.233:0.4, 0.233:0.5, 0.233:0.6 or any value between 0.233:(0.4-0.6).

[0087] And / or, the temperature of the second solvent thermal reaction is 170-190° C., and the time of the second solvent thermal reaction is 23-25 ​​hours.

[0088] For example, the temperature of the second solvothermal reaction can be 170°C, 180°C, 190°C or any value between 170-190°C, and the time of the second solvothermal reaction can be 23h, 24h, 25h or any value between 23-25h.

[0089] According to an embodiment of the present application, forming a main catalytic structure on a porous substrate by a solvothermal method comprises:

[0090] The porous substrate, the topological insulating material precursor, ethylene glycol and sodium hydroxide are mixed, and a third solvothermal reaction is carried out in a reactor to obtain a composite structure of the porous substrate and the topological insulating material;

[0091] A bismuth source, a sulfur source, a composite structure of a porous substrate and a topological insulating material, and ethylene glycol are mixed, and a fourth solvent thermal reaction is carried out in a reactor to obtain a hydrogen and oxygen evolution bifunctional water electrolysis catalyst.

[0092] According to an embodiment of the present application, the topological insulating material precursor includes Bi2O3 and TeO2, and the molar ratio of the Bi2O3 to the TeO2 is 1:(2-4); for example, the molar ratio of Bi2O3 to TeO2 can be 1:2, 1:3, 1:4 or any value between 1:(2-4).

[0093] And / or, the molar ratio of Bi2O3 to sodium hydroxide is 1:(18-22); for example, the molar ratio of Bi2O3 to sodium hydroxide can be 1:18, 1:19, 1:20, 1:21, 1:22 or any value between 1:(18-22).

[0094] And / or, when performing the third solvothermal reaction, the method further includes adding PVP to the reaction system, and the mass ratio of Bi2O3 to PVP is 0.233:(0.4-0.6); for example, the mass ratio of Bi2O3 to PVP can be 0.233:0.4, 0.233:0.5, 0.233:0.6 or any value between 0.233:(0.4-0.6).

[0095] and / or, the temperature of the third solvent thermal reaction is 170-190° C., and the time of the third solvent thermal reaction is 23-25 ​​h;

[0096] For example, the temperature of the third solvothermal reaction can be 170°C, 180°C, 190°C or any value between 170-190°C, and the time of the third solvothermal reaction can be 23h, 24h, 25h or any value between 23-25h.

[0097] and / or, the bismuth source comprises Bi(NO3)3 or a hydrate of Bi(NO3)3;

[0098] And / or, the sulfur source includes at least one of thioacetamide, sodium sulfide nonahydrate, thiourea, and sodium sulfite;

[0099] And / or, the molar ratio of the bismuth source to the sulfur source is 1:(11-13); for example, the molar ratio of the bismuth source to the sulfur source can be 1:11, 1:12, 1:12.6, 1:13 or any value in between 1:(11-13).

[0100] And / or, the molar ratio of the bismuth source to the Bi2O3 is 2:(0.9-1.1); for example, the molar ratio of the bismuth source to Bi2O3 can be any value between 2:0.9, 2:1, 2:1.1 or 2:(0.9-1.1).

[0101] And / or, the temperature of the fourth solvent thermal reaction is 170-190° C., and the time of the fourth solvent thermal reaction is 11-13 h.

[0102] For example, the temperature of the fourth solvothermal reaction can be 170°C, 180°C, 190°C or any value between 170-190°C, and the time of the fourth solvothermal reaction can be 11h, 12h, 13h or any value between 11-13h.

[0103] The present application also provides a water electrolysis device, which includes the hydrogen and oxygen evolution dual-function water electrolysis catalyst described above.

[0104] The embodiments of the present application will be described in detail below in conjunction with specific examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. If specific conditions are not specified in the examples, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0105] Preparation Example 1: Preparation of Bi2Te3

[0106] Preparation Example 1 provides a preparation method of Bi2Te3, wherein the sample is reacted at 180°C using 50ml polytetrafluoroethylene liner for 24h to obtain Bi2Te3 nanosheets, which specifically includes the following steps:

[0107] (1) Weigh 0.5 g of PVP and dissolve it in 33 ml of ethylene glycol. Stir continuously for 20 min.

[0108] (2) Weigh 0.233 g Bi2O3, 0.239 g TeO2, and 0.4 g NaOH and add them to the solution stirred in (1), and continue stirring for 3 h;

[0109] (3) The solution was transferred to a polytetrafluoroethylene liner, which was placed in a reactor and then transferred to an electric heated air drying oven at 180°C for reaction for 24 hours;

[0110] (4) After the reaction temperature has cooled, the solution is transferred to a centrifuge tube and washed multiple times with acetone, anhydrous ethanol, and deionized water at 10,000 rpm for 10 min;

[0111] (5) After cleaning, the mixture was transferred to an electric hot air drying oven and dried at 85°C for 12 h to obtain Bi2Te3 powder.

[0112] Depend on Figure 3 It can be seen that Bi2Te3 can be successfully prepared using the method of Preparation Example 1. Figure 4 It can be seen that the Bi2Te3 nanosheets prepared using the method of Preparation Example 1 have good crystal quality.

[0113] Preparation Example 2: Preparation of Bi2S3 material

[0114] Preparation Example 2 provides a method for preparing Bi2S3, comprising the following steps:

[0115] (1) Weigh 0.485 g Bi(NO3)3·5H2O and dissolve it in 15 ml ethylene glycol solution and stir for 15 min;

[0116] (2) Weigh 0.95 g of thioacetamide and dissolve it in 15 ml of ethylene glycol solution and stir until it is completely dissolved;

[0117] (3) dropping the solution in step (2) into the solution in step (1), and stirring the mixed solution again for 20 min;

[0118] (4) transferring the mixed solution in step (3) to a polytetrafluoroethylene liner, placing the liner in a reaction kettle and transferring it to an electric heated air drying oven at 180° C. for reaction for 12 h;

[0119] (5) After the reaction temperature has cooled, the solution is transferred to a centrifuge tube and washed multiple times with acetone, anhydrous ethanol, and deionized water at 10,000 rpm for 10 min;

[0120] (6) After cleaning, the mixture was transferred to an electric hot air drying oven and dried at 85°C for 12 h to obtain Bi2S3 powder.

[0121] Figure 5 The XRD pattern of Bi2S3 prepared in Preparation Example 2 is shown in Figure 5 It can be seen that Preparation Example 2 successfully prepared Bi2S3.

[0122] Example 1

[0123] Embodiment 1 provides a preparation method of a bifunctional water electrolysis catalyst Bi2Te3-Bi2S3-NMF for hydrogen and oxygen evolution, comprising the following steps:

[0124] (1) Cut the molybdenum nickel foam into small pieces of (0.5-2)*(0.5-2) cm, place it in 3M / L dilute hydrochloric acid for ultrasonic treatment for 5-15 minutes to remove the oxide layer, rinse it with deionized water for 5-10 times, then add the substrate to acetone for ultrasonic treatment for 5-15 minutes to remove the surface organic matter, take out the substrate and use anhydrous ethanol for ultrasonic treatment for 5-15 minutes again to remove the acetone residue, rinse it with deionized water again for 5-10 times, and then place it in a 30-50°C electric heating blast drying oven for drying for standby use;

[0125] (2) Weigh 0.485 g Bi(NO3)3·5H2O and dissolve it in 15 ml ethylene glycol solution and stir for 15 min;

[0126] (3) Weigh 0.95 g of thioacetamide and dissolve it in 15 ml of ethylene glycol solution and stir until it is completely dissolved;

[0127] (4) dropping the solution in step (3) into the solution in step (2), and stirring the mixed solution again for 20 min;

[0128] (5) transferring the mixed solution in step (4) to a polytetrafluoroethylene liner, adding the cleaned and dried foam metal in step (1), placing the liner in a reactor and transferring it to an electric heated air drying oven for reaction at 180° C. for 12 h;

[0129] (6) After the reaction temperature has dropped, the foamed metal is taken out and repeatedly washed with anhydrous ethanol and deionized water;

[0130] (7) After the cleaning, the mixture was transferred to an electric hot air drying oven at 55° C. and dried for 12 h to obtain a Bi2S3-NMF composite material;

[0131] (8) Weigh 0.5 g of PVP and dissolve it in 33 ml of ethylene glycol. Stir continuously for 20 min.

[0132] (9) Weigh 0.233 g Bi2O3, 0.239 g TeO2, and 0.4 g NaOH and add them to the stirred solution in (8), and continue stirring for 3 h;

[0133] (10) transferring the solution to a polytetrafluoroethylene liner, adding the Bi2S3-NMF composite material dried in step (7), placing the liner in a reactor and transferring it to an electric heated air drying oven at 180° C. for reaction for 24 h;

[0134] (11) After the reaction temperature has dropped, the composite material is taken out and repeatedly washed with anhydrous ethanol and deionized water;

[0135] (12) The mixture was transferred into an electric blower dryer and dried at 55 °C to obtain a Bi2Te3-Bi2S3-NMF composite material, which is a bifunctional water electrolysis catalyst for hydrogen and oxygen evolution.

[0136] The SEM image of the cross section of the Bi2Te3-Bi2S3-NMF composite material prepared in Example 1 is as follows: Figure 6 As shown by Figure 6 An obvious layered structure can be seen, with the top layer being Bi2Te3 nanoflowers, the middle layer being Bi2S3, and the bottom layer being NMF foam metal.

[0137] Example 2

[0138] Embodiment 2 provides a method for preparing a bifunctional water electrolysis catalyst Bi2S3-Bi2Te3-NMF for hydrogen and oxygen evolution, comprising the following steps:

[0139] (1) Cut the molybdenum nickel foam into small pieces of (0.5-2)*(0.5-2) cm, place it in 3M / L dilute hydrochloric acid for ultrasonic treatment for 5-15 minutes to remove the oxide layer, rinse it with deionized water for 5-10 times, then add the substrate to acetone for ultrasonic treatment for 5-15 minutes to remove the surface organic matter, take out the substrate and use anhydrous ethanol for ultrasonic treatment for 5-15 minutes again to remove the acetone residue, rinse it with deionized water again for 5-10 times, and then place it in a 30-50°C electric heating blast drying oven for drying for standby use;

[0140] (2) Weigh 0.5 g of PVP and dissolve it in 33 ml of ethylene glycol. Stir continuously for 20 min.

[0141] (3) Weigh 0.233 g Bi2O3, 0.239 g TeO2, and 0.4 g NaOH and add them to the solution stirred in (2), and continue stirring for 3 h;

[0142] (4) transferring the solution to a polytetrafluoroethylene liner, adding the NMF substrate dried in step (1), placing the liner in a reactor, and transferring it to an electric heated air drying oven at 180° C. for reaction for 24 h;

[0143] (5) After the reaction temperature has dropped, the composite material is taken out and repeatedly washed with anhydrous ethanol and deionized water;

[0144] (6) Transferring to an electric hot air dryer and drying at 55°C to obtain Bi2Te3-NMF;

[0145] (7) Weigh 0.485 g Bi(NO3)3·5H2O and dissolve it in 15 ml ethylene glycol solution and stir for 15 min;

[0146] (8) Weigh 0.95 g of thioacetamide and dissolve it in 15 ml of ethylene glycol solution and stir until completely dissolved;

[0147] (9) dropping the solution in step (8) into the solution in step (7), and stirring the mixed solution again for 20 min;

[0148] (10) transferring the mixed solution in step (9) to a polytetrafluoroethylene liner, adding the cleaned and dried foam metal in step (6), placing the liner in a reactor and transferring it to an electric heated air drying oven at 180° C. for reaction for 12 h;

[0149] (11) After the reaction temperature has dropped, the foamed metal is taken out and repeatedly washed with anhydrous ethanol and deionized water;

[0150] (12) After cleaning, the mixture was transferred to an electric forced air drying oven at 55 °C for 12 h to obtain a Bi2S3-Bi2Te3-NMF composite material, which is a bifunctional water electrolysis catalyst for hydrogen and oxygen evolution.

[0151] The SEM image of the cross section of the Bi2S3-Bi2Te3-NMF composite material prepared in Example 2 is as follows: Figure 7 As shown by Figure 7 An obvious layered structure can be seen, with the top layer being Bi2S3 nanorods, the middle layer being Bi2Te3, and the bottom layer being NMF foam metal.

[0152] Comparative Example 1

[0153] Comparative Example 1 provides a method for preparing a composite material of Bi2Te3 nanosheets and foamed molybdenum-nickel metal, wherein the sample is reacted at 180°C using a 50ml polytetrafluoroethylene liner for 24h to obtain a composite material of Bi2Te3 nanosheets and foamed molybdenum-nickel metal, specifically comprising the following steps:

[0154] (1) Cut the molybdenum nickel foam into small pieces of (0.5-2)*(0.5-2) cm, place it in 3M / L dilute hydrochloric acid for ultrasonic treatment for 5-15 minutes to remove the oxide layer, rinse it with deionized water for 5-10 times, then add the substrate to acetone for ultrasonic treatment for 5-15 minutes to remove the surface organic matter, take out the substrate and use anhydrous ethanol for ultrasonic treatment for 5-15 minutes again to remove the acetone residue, rinse it with deionized water again for 5-10 times, and then place it in a 30-50°C electric heating blast drying oven for drying for standby use;

[0155] (2) Weigh 0.5 g of PVP and dissolve it in 33 ml of ethylene glycol. Stir continuously for 20 min.

[0156] (3) Weigh 0.233 g Bi2O3, 0.239 g TeO2, and 0.4 g NaOH and add them to the solution stirred in step (2), and continue stirring for 3 h;

[0157] (4) The solution was transferred to a polytetrafluoroethylene liner and placed in a dried foam metal substrate. The liner was placed in a reactor and then transferred to an electric heated air drying oven at 180° C. for reaction for 24 h.

[0158] (5) After the reaction temperature has dropped, the foamed metal is taken out and repeatedly washed with anhydrous ethanol and deionized water;

[0159] (6) After cleaning, the mixture was transferred to an electric hot air drying oven and dried at 85°C for 12 h to obtain a Bi2Te3-NMF composite material.

[0160] Figure 8 The SEM image of the raw material NMF used in Comparative Example 1 is shown in FIG. Figure 8 It can be seen that the surface of the original NMF substrate is flat and smooth after cleaning, without obvious impurities.

[0161] Fig. 9The SEM image of Bi2Te3-NMF prepared in Comparative Example 1 is shown in FIG. Fig. 9 It can be seen that after the solvothermal reaction, Bi2Te3 and the substrate are composited evenly and flatly, showing obvious stratification.

[0162] Fig.10 The SEM image of Bi2Te3-NMF prepared in Comparative Example 1 is shown in FIG. Fig.10 It can be seen that the Bi2Te3 composited on the NMF substrate is hydrangea-shaped and evenly distributed.

[0163] Comparative Example 2

[0164] Comparative Example 2 provides a method for preparing a Bi2S3-NMF composite material, comprising the following steps:

[0165] (1) Cut the molybdenum nickel foam into small pieces of (0.5-2)*(0.5-2) cm, place it in 3M / L dilute hydrochloric acid for ultrasonic treatment for 5-15 minutes to remove the oxide layer, rinse it with deionized water for 5-10 times, then add the substrate to acetone for ultrasonic treatment for 5-15 minutes to remove the surface organic matter, take out the substrate and use anhydrous ethanol for ultrasonic treatment for 5-15 minutes again to remove the acetone residue, rinse it with deionized water again for 5-10 times, and then place it in a 30-50°C electric heating blast drying oven for drying for standby use;

[0166] (2) Weigh 0.485 g Bi(NO3)3·5H2O and dissolve it in 15 ml ethylene glycol solution and stir for 15 min;

[0167] (3) Weigh 0.95 g of thioacetamide and dissolve it in 15 ml of ethylene glycol solution and stir until it is completely dissolved;

[0168] (4) dropping the solution in step (3) into the solution in step (2), and stirring the mixed solution again for 20 min;

[0169] (5) transferring the mixed solution in step (4) and the foamed metal in step (1) into a polytetrafluoroethylene liner, placing the liner into a reaction kettle and transferring it to an electric heated air drying oven for reaction at 180° C. for 12 h;

[0170] (6) After the reaction temperature has dropped, the foamed metal is taken out and repeatedly washed with anhydrous ethanol and deionized water;

[0171] (7) After cleaning, the mixture was transferred to an electric hot air drying oven and dried at 55 °C for 12 h to obtain a Bi2S3-NMF composite material.

[0172] Fig.11 , Fig.12And the test conditions of Table 1: a carbon rod and a saturated calomel electrode were used as the counter electrode and the reference electrode, respectively, the catalyst prepared in the present application was used as the working electrode, and a three-electrode system was used to perform the test in 1 M KOH electrolyte at room temperature (linear sweep voltammetry, LSV).

[0173] Table 1 is a comparison table of overpotentials of HER reaction and OER reaction of NMF, Example 1-2 and Comparative Example 1-2 catalysts at a current density of 10 mA.

[0174] Table 1 Comparison of overpotentials of HER reaction and OER reaction of NMF, Example 1-2 and Comparative Example 1-2 catalysts at 10 mA current density

[0175]

[0176] from Fig.11 , Fig.12 As can be seen from Table 1, compared with NMF and Comparative Examples 1-2, the catalyst of Example 1-2 can simultaneously have a lower overpotential for the HER reaction and a lower overpotential for the OER reaction. Specifically, after NMF is compounded with bismuth telluride, the reaction overpotential is significantly reduced, and the catalytic ability is significantly enhanced. Before the addition of bismuth sulfide, Bi2Te3-NMF partially fell off after the test, and the shedding improved after the introduction of bismuth sulfide. The catalyst of Example 1-2 has excellent catalytic ability for both OER and HER reactions. The results show that the catalyst of Example 1-2 can be used as an efficient bifunctional water electrolysis catalyst for oxygen and hydrogen evolution under alkaline conditions.

[0177] Table 2 is a comparison table of the catalytic performance of the catalyst of the present application and the reported existing catalysts.

[0178] Table 2 Comparison of catalytic performance of the catalyst of this application and the existing catalyst reported

[0179]

[0180] It can be seen from Table 2 that compared with the reported water electrolysis catalysts, the catalyst of the present application has a lower overpotential for the OER reaction, and the catalyst of the present application also has a lower overpotential for the HER reaction.

[0181] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

[0182] In addition, those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present application and form different embodiments. For example, in the above claims, any one of the claimed embodiments may be used in any combination. The information disclosed in this background technology section is intended only to deepen the understanding of the overall background technology of the present application and should not be regarded as an admission or in any form of implication that the information constitutes prior art known to those skilled in the art.

Claims

1. A bifunctional water electrolysis catalyst for hydrogen and oxygen evolution, characterized in that: It comprises: a porous substrate and a main catalytic structure located on the substrate, wherein the main catalytic structure comprises a topological insulating layer and a Bi2S3 layer which are stacked.

2. The hydrogen and oxygen evolution bifunctional water electrolysis catalyst according to claim 1, characterized in that: The topological insulating layer is located between the porous substrate and the Bi2S3 layer, or the Bi2S3 layer is located between the porous substrate and the topological insulating layer.

3. The hydrogen and oxygen evolution bifunctional water electrolysis catalyst according to claim 1, characterized in that: The porous substrate includes molybdenum nickel foam.

4. The bifunctional water electrolysis catalyst for hydrogen and oxygen evolution according to any one of claims 1 to 3, characterized in that: The material forming the topological insulating layer includes any one of Bi2Te3, Bi2Se3, and Bi2Se2Te.

5. A method for preparing a dual-functional water electrolysis catalyst for hydrogen and oxygen evolution as claimed in any one of claims 1 to 4, characterized in that: include: A main catalytic structure is formed on a porous substrate by a solvothermal method to obtain a bifunctional water electrolysis catalyst for hydrogen and oxygen evolution; wherein the main catalytic structure includes a topological insulating layer and a Bi2S3 layer arranged in a stacked manner.

6. The method for preparing the hydrogen and oxygen evolution bifunctional water electrolysis catalyst according to claim 5, characterized in that: The method of forming a main catalytic structure on a porous substrate by a solvothermal method comprises: The porous substrate, bismuth source, sulfur source and ethylene glycol are mixed, and a first solvent thermal reaction is carried out in a reactor to obtain a composite structure of the porous substrate and Bi2S3; The topological insulating material precursor, the composite structure of the porous substrate and Bi2S3 and sodium hydroxide are mixed, and a second solvent thermal reaction is carried out in a reactor to obtain a hydrogen and oxygen evolution bifunctional water electrolysis catalyst.

7. The method for preparing the hydrogen and oxygen evolution bifunctional water electrolysis catalyst according to claim 6, characterized in that: The bismuth source includes Bi(NO3)3 or a hydrate of Bi(NO3)3; And / or, the sulfur source includes at least one of thioacetamide, sodium sulfide nonahydrate, thiourea, and sodium sulfite; And / or, the molar ratio of the bismuth source to the sulfur source is 1:(11-13); and / or, the temperature of the first solvent thermal reaction is 170-190° C., and the time of the first solvent thermal reaction is 11-13 h; And / or, the topological insulating material precursor comprises Bi2O3 and TeO2, and the molar ratio of Bi2O3 to TeO2 is 1:(2-4); and / or, the molar ratio of the bismuth source to the Bi2O3 is 2:(0.9-1.1); and / or, the molar ratio of the Bi2O3 to the sodium hydroxide is 1:(18-22); And / or, when performing the second solvothermal reaction, the method further comprises adding PVP to the reaction system, wherein the mass ratio of the Bi2O3 to the PVP is 0.233:(0.4-0.6); And / or, the temperature of the second solvent thermal reaction is 170-190° C., and the time of the second solvent thermal reaction is 23-25 ​​hours.

8. The method for preparing the hydrogen and oxygen evolution bifunctional water electrolysis catalyst according to claim 5, characterized in that: The method of forming a main catalytic structure on a porous substrate by a solvothermal method comprises: The porous substrate, the topological insulating material precursor, ethylene glycol and sodium hydroxide are mixed, and a third solvothermal reaction is carried out in a reactor to obtain a composite structure of the porous substrate and the topological insulating material; A bismuth source, a sulfur source, a composite structure of the porous substrate and the topological insulating material, and ethylene glycol are mixed, and a fourth solvent thermal reaction is carried out in a reactor to obtain a hydrogen and oxygen evolution bifunctional water electrolysis catalyst.

9. The method for preparing the hydrogen and oxygen evolution bifunctional water electrolysis catalyst according to claim 8, characterized in that: The topological insulating material precursor comprises Bi2O3 and TeO2, and the molar ratio of the Bi2O3 to the TeO2 is 1:(2-4); and / or, the molar ratio of the Bi2O3 to the sodium hydroxide is 1:(18-22); And / or, when performing the third solvothermal reaction, the method further comprises adding PVP to the reaction system, wherein the mass ratio of the Bi2O3 to the PVP is 0.233:(0.4-0.6); and / or, the temperature of the third solvent thermal reaction is 170-190° C., and the time of the third solvent thermal reaction is 23-25 ​​h; and / or, the bismuth source comprises Bi(NO3)3 or a hydrate of Bi(NO3)3; And / or, the sulfur source includes at least one of thioacetamide, sodium sulfide nonahydrate, thiourea, and sodium sulfite; And / or, the molar ratio of the bismuth source to the sulfur source is 1:(11-13); and / or, the molar ratio of the bismuth source to the Bi2O3 is 2:(0.9-1.1); And / or, the temperature of the fourth solvent thermal reaction is 170-190° C., and the time of the fourth solvent thermal reaction is 11-13 h.

10. A water electrolysis device, characterized in that: The water electrolysis device comprises the hydrogen and oxygen evolution bifunctional water electrolysis catalyst according to any one of claims 1 to 4.

Images