A dual-support single-atom catalyst and its preparation method and application

Abstract

The present invention belongs to the field of electrocatalytic materials, and in particular refers to a dual-carrier single-atom catalyst, a preparation method thereof, and an application thereof. Density functional theory results show that the introduction of sulfur vacancies in carbon-intercalated MoS2 can produce an "electron lock" effect to capture negative ion metal groups and realize the in-situ anchoring of metal single atoms between the intercalated carbon and the sulfur vacancies. The present invention uses C-MoS2 with rich sulfur vacancies, carbon intercalation, and egg yolk and eggshell structure as a dual carrier, selects negative ion metal groups as metal sources, and can control the preparation of C-M-MoS2 single-atom catalysts with a dual-carrier environment. This synthesis technology is universal and can be used for the preparation of 8 single-atom catalysts. The loading amount of metal atoms can be controlled within the range of 0.77-5.71 wt%, and has excellent acidic electrocatalytic hydrogen evolution performance. The invention relates to the precise regulation of the microenvironment of single-atom catalysts, and provides ideas for constructing highly active single-atom catalysts using dual carriers.

Description

Technical Field

[0001] The present invention belongs to the field of electrocatalytic materials, relates to the controllable synthesis and functional application of electrocatalysts, and particularly refers to a dual-carrier single-atom catalyst and its preparation method and application. Background Art

[0002] Electrochemical water splitting is a viable green hydrogen production technology that is crucial to addressing energy needs and carbon neutrality. Acidic electrocatalytic hydrogen evolution is highly efficient and pure and is widely welcomed. In the past few decades, people have been committed to improving electrocatalysts to reduce costs and save energy. Since Professor Zhang Tao first proposed the concept of single-atom catalysis, single-atom catalysts with maximum atomic efficiency have attracted widespread attention. However, high surface energy makes single atoms more inclined to aggregate in electrocatalysis. Thanks to the electronic metal-support interaction, the substrate can stabilize single atoms and regulate the electronic structure of single-atom catalysts. Therefore, it is very important to develop an ideal support for the controllable synthesis of single-atom catalysts while solving the problems of activity and durability.

[0003] Among the reported supports, carbon-based materials can provide abundant sites for metal single-atom anchoring due to their large specific surface area, abundant defects, and heteroatom doping. Carbon-based single-atom catalysts anchored by heteroatoms in horizontal, axial, and asymmetric coordination structures show greater advantages than single-anchor catalysts. According to the literature ( Mater. Today Energy , 2022, 26, 101017) reported that metal single atoms (MN) anchored on nitrogen-doped carbon (NC) supports x -C) is a typical example. In particular, MN x The intrinsic activity and site density of -C can be adjusted by adjusting the coordination microenvironment of saturated, unsaturated, and supersaturated sites, resulting in specific catalytic performance. The Chinese patent (CN115155642A) induces uniform anchoring of metal atoms on the NC matrix, resulting in a single-atom catalyst with high electrocatalytic oxygen reduction activity and stability.

[0004] As another class of non-carbon-based materials, supports such as metal oxides, metal sulfides, carbides, nitrides, phosphides, and organic frameworks have also attracted increasing attention because they have unique advantages in stabilizing / dispersing single atoms, such as adjustable configuration, composition, and interface. The anchoring mechanisms are as follows: (1) Cation vacancies: Cation vacancies in supports can provide large spaces for atomic adsorption, regulate the electron density at the interface, and activate local metal atoms to promote reaction kinetics; (2) Anion vacancies: Anion vacancies including O, S, Se, and P serve as anchoring sites for metal atom loading with the help of spatial confinement or charge attraction to achieve single-atom catalysts with enhanced dd orbitals between M1 and M2, thereby developing highly active electrocatalysts; (3) Determined strategies: Crystal plane dependence and strain are also effective ways to generate strong electronic metal-support interactions to achieve synergistically enhanced catalytic behavior. Overall, the activity, selectivity, and durability of metal single atoms are improved on non-carbon-based supports. A Chinese patent (CN114950412A) uses various metal oxide nanoclusters as carriers to in situ prepare single-atom catalysts with excellent catalytic performance and stability. To address the low single-atom loading and easy aggregation and deactivation of single-atom catalysts, a Chinese patent (CN108686680A) relates to a method for preparing and applying a single-atom ruthenium catalyst. This catalyst uses cadmium sulfide nanomaterials as a carrier, resulting in a highly dispersed surface of ruthenium, thereby maximizing catalytic efficiency.

[0005] In summary, the interaction between the support and the metal atoms will determine the activity and stability of the single-atom catalyst. Regulating the coordination structure of the single-atom catalyst on a carbon-based or non-carbon-based support can greatly promote the electrocatalytic reaction. However, due to the lack of a universal synthesis method, it remains a challenge to precisely develop single-atom catalysts with spatial positions and dual-anchored microenvironments. Currently, the preparation of efficient single-atom catalysts still faces the following two major problems: (1) Most studies focus on regulating the coordination environment of a single support, and no work involving dual-support activation and stabilization of single atoms has been reported; (2) Increasing the loading of single atoms remains a difficult problem to solve the hydrogen production efficiency of the catalyst. Summary of the Invention

[0006] To address these technical issues, the present invention proposes a dual-support single-atom catalyst, along with its universal preparation method and application. Using C-MoS2, a material rich in sulfur vacancies, carbon intercalation, and a yolk-eggshell structure, as a support, the present invention precisely regulates the microenvironment of the single-atom catalyst to address key challenges in catalytic activity and stability, providing insights into the construction of highly efficient single-atom catalysts using dual supports.

[0007] A method for preparing a dual-support single-atom catalyst, characterized by the following steps:

[0008] (1) Synthesis of dual-support C-MoS2 with sulfur vacancies, carbon intercalation, and yolk-eggshell structure;

[0009] (2) dispersing the dual carrier prepared in step (1) in a mixed solution of deionized water and ethanol to obtain solution I;

[0010] (3) Add the negative ion metal salt to solution I and stir to obtain solution II;

[0011] (4) Solution II is centrifuged and washed, and subjected to gradient heat treatment to obtain a dual-support single-atom catalyst.

[0012] Preferably, the synthesis method of the dual-carrier C-MoS2 in step (1) is as follows: dissolve 1 mmol of sodium molybdate dihydrate and 0.4 g of glucose in 300 mL of deionized water, and ultrasonically obtain an aqueous phase solution; dissolve 15 mmol of hexadecyltrimethylammonium bromide in 100 mL of n-butanol, and ultrasonically obtain an oil phase solution; add the aqueous phase solution dropwise to the oil phase solution, stir for 2 h, then add 50 mL of ethylene glycol and 0.7 mL of hydrochloric acid in sequence, stir for 1 h, add 12 mmol of thiourea, continue stirring for 3 h, place in a closed container and undergo a two-step solvent thermal reaction (180 ° C, 4 h → 220 ° C, 20 h) to obtain a precursor, and then place the precursor in a tube furnace and perform gradient heat treatment under argon atmosphere (200 ° C, 2 h → 550 ° C, 2 h → 750 ° C, 5 h, with a heating rate of 2 ° C / min) to obtain the dual-carrier C-MoS2.

[0013] Preferably, in step (2), the volume ratio of deionized water to ethanol is (1-20):80, and the concentration of the dual-carrier C-MoS2 in solution I is 0.1-10 mg / mL.

[0014] Preferably, in step (3), the concentration of the negative ion metal salt is 0.001-0.1 mmol / mL, such as sodium permanganate monohydrate, potassium tetracyanonickel (II) hydrate, potassium hexacyanocobalt (III) acid, potassium hexacyanoferrous (II) acid, lithium tetrachlorocuprate, potassium cadmium cyanide, sodium zinc tetrahydroxide and sodium tungstate dihydrate.

[0015] Preferably, the gradient heat treatment in step (4) is carried out as follows: first, the temperature is maintained at 160-250 °C in an argon atmosphere for 1-3 h, and then the temperature is increased to 650-850 °C and maintained for 1-9 h.

[0016] According to density functional theory: the "electronic locks" derived from intercalated carbon and sulfur vacancies can capture negative ion metal groups and accurately achieve double anchoring of metal single atoms, that is, intercalated carbon and sulfur vacancy co-anchoring (CMS v ).

[0017] This synthesis technology is universal and can be used for the controllable preparation of eight single-atom catalysts: Co, Ni, Fe, Zn, W, Cu, Mn and Cd. The loading amount of metal atoms can be controlled in the range of 0.77-5.71wt%.

[0018] The hydrogen evolution overpotential of the dual-support C-Co-MoS2 single-atom catalyst is 17 mV (10 mA / cm 2 ), which has better activity than all MoS2-based single-atom catalysts reported so far.

[0019] The present invention has the following beneficial effects:

[0020] 1. Based on the results of density functional theory calculations, this paper proposes a synthesis strategy for dual-support single-atom catalysts: the electron-deficient sites generated by intercalated carbon and sulfur vacancies can accurately capture anionic metal groups to achieve dual anchoring of metal atoms between sulfur vacancies and intercalated carbon, providing theoretical support for similar dual-support stabilization of metal atoms with anionic vacancies.

[0021] 2. The present invention uses C-MoS2 material with sulfur vacancies, carbon intercalation, and egg yolk-shell structure as a dual carrier for the following reasons: (1) the dual advantages of coupling carbon-based and non-carbon-based carriers; (2) high-content single-atom loading under dual anchoring; (3) synergistic advantages of the egg yolk-shell structure to promote liquid mesoscopic mass transfer and improve water electrolysis efficiency. Anion metal groups are selected as single-atom metal sources, and after a gradient heat treatment process (in argon atmosphere: 160-250 ℃ for 1-3 h → 650-850 ℃ for 1-9 h), the double anchoring of single atoms between intercalated carbon and sulfur vacancies is accurately achieved, and a dual-carrier coordination environment (CMS) can be prepared in a controlled manner. v ) of CM-MoS2 single-atom catalyst; this synthesis technology has the advantage of universality and can be used for the controllable preparation of eight single-atom catalysts: Co, Ni, Fe, Zn, W, Cu, Mn and Cd; the loading amount of metal atoms can be regulated in the range of 0.77-5.71wt%; this invention involves the design and preparation of a dual-coordination environment for single-atom catalysts, providing ideas for the synthesis of highly active single-atom catalysts using dual carriers.

[0022] 3. The series of dual-support single-atom catalysts prepared by the present invention were tested for hydrogen evolution performance in acidic water electrolysis. The results showed that the overpotential of the single-atom catalyst C-Co-MoS2 in 0.5 mol / L H2SO4 electrolyte was only 17 mV (10 mA / cm 2 ), which is superior to all current MoS2-based single-atom catalysts; in addition, the catalyst has a high 2 , 20mA / cm 2 , 50 mA / cm 2, 100 mA / cm 2 ) showed a continuous and stable electrolysis ability of 240 h. The dual-support single-atom catalyst prepared by this invention has the application potential of energy-saving and stable electrolysis of water to produce hydrogen. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 The electron difference density (EDDs) diagram of C-MoS2 and the double anchoring model of CM-MoS2 in Examples 1-9.

[0025] Figure 2 The field emission scanning electron microscope (FESEM) photograph and particle size distribution diagram of C-MoS2 in Example 1 are shown.

[0026] Figure 3 Transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) images, and electron paramagnetic resonance (EPR) spectra of C-MoS2 in Example 1.

[0027] Figure 4 This is the X-ray diffraction (XRD) pattern of the CM-MoS2 dual-support single-atom catalyst in Example 2-9.

[0028] Figure 5 This is the FESEM photo of C-Co-MoS2 in Example 2.

[0029] Figure 6 This is the FESEM photo of C-Fe-MoS2 in Example 3.

[0030] Figure 7 This is the FESEM photo of C-Ni-MoS2 in Example 4.

[0031] Figure 8 This is the FESEM photo of C-Cu-MoS2 in Example 5.

[0032] Figure 9 This is the FESEM photo of C-Zn-MoS2 in Example 6.

[0033] Figure 10 This is the FESEM photo of C-Mn-MoS2 in Example 7.

[0034] Figure 11 This is the FESEM photo of C-Cd-MoS2 in Example 8.

[0035] Figure 12 This is the FESEM photo of CW-MoS2 in Example 9.

[0036] Figure 13 TEM, HRTEM photos, spherical aberration electron microscope pictures, low-magnification HAADF and corresponding EDS surface analysis photos of C-Co-MoS2 in Example 2.

[0037] Figure 14 TEM, HRTEM images, low-magnification HAADF and corresponding EDS surface analysis images of C-Fe-MoS2 in Example 3.

[0038] Figure 15 TEM, HRTEM images, low-magnification HAADF and corresponding EDS surface analysis images of C-Ni-MoS2 of Example 4.

[0039] Figure 16 TEM, HRTEM images, low-magnification HAADF and corresponding EDS surface analysis images of C-Cu-MoS2 in Example 5.

[0040] Figure 17 TEM, HRTEM images, low-magnification HAADF and corresponding EDS surface analysis images of C-Zn-MoS2 of Example 6.

[0041] Figure 18 TEM, HRTEM images, low-magnification HAADF and corresponding EDS surface analysis images of C-Mn-MoS2 of Example 7.

[0042] Figure 19 TEM, HRTEM images, low-magnification HAADF and corresponding EDS surface analysis images of C-Cd-MoS2 of Example 8.

[0043] Figure 20 TEM, HRTEM images, low-magnification HAADF and corresponding EDS surface analysis images of CW-MoS2 in Example 9.

[0044] Figure 21 This is the synchrotron radiation near-edge absorption spectrum and valence linear relationship curve of C-Co-MoS2 in Example 2.

[0045] Figure 22 This is the extended edge radiation absorption spectrum of C-Co-MoS2 in Example 2.

[0046] Figure 23Comparison of polarization curves for hydrogen evolution in water electrolysis of CM-MoS2 in Examples 2-9.

[0047] Figure 24 Comparison of the CM-MoS2 Tafel slope curves in Examples 2-9.

[0048] Figure 25 This is a comparison chart of the specific capacitance curves of CM-MoS2 in Examples 2-9.

[0049] Figure 26 This is the stability curve of C-Co-MoS2 at different current densities in Example 2.

[0050] Figure 27 These are the overall and local HAADF and corresponding EDS surface analysis photos of C-Co-MoS2 after cycling in Example 2. DETAILED DESCRIPTION

[0051] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0052] Example 1

[0053] Preparation of egg yolk and eggshell structure C-MoS2: 1 mmol sodium molybdate dihydrate and 0.4 g glucose were dissolved in 300 mL deionized water and ultrasonicated to obtain an aqueous phase solution; 15 mmol hexadecyltrimethylammonium bromide was dissolved in 100 mL n-butanol and ultrasonicated to obtain an oil phase solution; the aqueous phase solution was added dropwise to the oil phase solution, stirred for 2 h, and then 50 mL ethylene glycol and 0.7 mL hydrochloric acid were added in sequence. After stirring for 1 h, 12 mmol thiourea was added and stirred for 3 h before solvothermal reaction. The reaction was first carried out at 180 °C for 4 h, then heated to 220 °C and continued to react for 20 h; after centrifugation and washing, monodispersed MoS2-(CTAB)2S was obtained. z Precursor; the precursor is subjected to gradient heat treatment, specifically: under argon atmosphere in a tubular furnace, the temperature is increased at a rate of 2 ° C / min, first raised to 350 ° C and held for 2 h, then raised to 450 ° C and held for 2 h, and finally raised to 750 ° C and held for 5 h to obtain egg yolk and eggshell structure C-MoS2.

[0054] Figure 1 The EDDs model of the egg yolk-eggshell structure C-MoS2 in Example 1 was included. The calculation results showed that electron loss could be generated at the intercalated carbon and sulfur vacancies; Figure 2The FESEM photo and particle size distribution picture of the egg yolk and eggshell structure C-MoS2 in Example 1. From the schematic diagram, it can be seen that the C-MoS2 is uniformly monodispersed and the carrier particle size is about 615 nm; Figure 3 The TEM photo, HRTEM photo and EPR curve of the yolk-eggshell structure C-MoS2 in Example 1 show that due to the embedding of carbon (0.33 nm) in the (002) plane of MoS2, the interlayer distance is expanded from 0.62 nm to 0.96 nm, as well as the lattice fringes corresponding to the (100) plane of MoS2. It can be seen from the EPR curve that when intercalated carbon is introduced into MoS2, a significant sulfur vacancy signal with a g factor of 2.003 appears.

[0055] Example 2

[0056] The preparation steps of egg yolk and eggshell structure C-MoS2 are the same as those in Example 1.

[0057] First, the egg yolk and eggshell structure C-MoS2 was uniformly dispersed in a mixed solution of 20 mL of deionized water and 80 mL of ethanol to prepare a solution with a concentration of 5 mg / mL; secondly, potassium hexacyanocobaltate (III) was added to the above solution to prepare a solution concentration of 0.05 mmol / mL, stirred and then centrifuged and washed; the obtained product was then subjected to a gradient heat treatment with the specific parameters: keeping it at 200 °C in argon in a tubular furnace for 2 h; heating to 750 °C and treating for 5 h to obtain a dual-support C-Co-MoS2 single-atom catalyst.

[0058] Figure 1 Including the dual-anchor model of the dual-support C-Co-MoS2 single-atom catalyst in Example 2, density functional theory shows that the introduction of sulfur vacancies in MoS2 containing intercalated carbon can generate "electron locks" to capture negative ion metal groups and achieve in situ anchoring of metal single atoms; Figure 4 The XRD pattern of the dual-support C-Co-MoS2 single-atom catalyst in Example 2 shows a broad peak of carbon and a typical peak of 2H-MoS2. The broad peak of the extended layer around 9.3° is contributed by the intercalated carbon and the MoS2 (002) plane. The carbon peak is marked with ◆. Figure 5 This is the FESEM image of the dual-support C-Co-MoS2 single-atom catalyst in Example 2, showing the monodisperse and uniform distribution of the material; Figure 13TEM photos, HRTEM photos, spherical aberration electron microscopy photos, low-magnification HAADF photos and corresponding EDS surface analysis photos of the dual-support C-Co-MoS2 single-atom catalyst in Example 2, wherein the HRTEM photo can be observed due to the embedding of carbon (0.33 nm) in the (002) plane of MoS2, the interlayer spacing is expanded from 0.62 nm to 0.96 nm, and the lattice fringes corresponding to the (100) plane of MoS2, the spherical aberration electron microscopy photo can be observed to be uniformly distributed on the surface and between layers of the material, the low-magnification HAADF and the corresponding EDS surface analysis photos show that Mo, S, C, and Co are also uniformly distributed. The above results prove that the Co single atom is successfully loaded on C-MoS2; Figure 21 The synchrotron radiation X-ray absorption near-edge structure spectrum of Co in Example 2 and the linear relationship curve obtained by the area integration method show that the peaks of the dual-support C-Co-MoS2 single-atom catalyst are located between the peaks of the Co foil and the CoO reference, respectively, confirming that the valence state of Co in the dual-support C-Co-MoS2 single-atom catalyst is between 0 and +2. From the linear relationship curve, it can be concluded that the accurate valence state of Co is +1.75; Figure 22 The extended edge radiation absorption diagram of Co in Example 2 shows that in the dual-support C-Co-MoS2 single-atom catalyst, the main peak at 1.39 belongs to Co-C, which is different from the Co-O peak in CoO at 1.68. No Co-Co peak was detected, indicating that the Co element mainly exists in the form of single atoms, and the peak at 2.43 can be attributed to Co-Mo. The material was tested using a traditional three-electrode system. Figure 23 The polarization curve of the dual-support C-Co-MoS2 single-atom catalyst in Example 2 shows an overpotential as low as 17 mV, which is better than other dual-support CM-MoS2 single-atom catalysts; Figure 24 The Tafel slope curve of the dual-support C-Co-MoS2 single-atom catalyst in Example 2 is included. The results show that the Tafel slope is as low as 32 mV / dec, which is better than other dual-support CM-MoS2 single-atom catalysts; Figure 25 The specific capacitance curve of the dual-support C-Co-MoS2 single-atom catalyst in Example 2 shows a specific capacitance of up to 9.25 mF / cm 2 , superior to other dual-support CM-MoS2 single-atom catalysts; Figure 26 The stability curve of the dual-support C-Co-MoS2 single-atom catalyst in Example 2 at different current densities proves that the material has excellent stability; Figure 27The HAADF and EDS surface analysis photos of the dual-support C-Co-MoS2 single-atom catalyst after cycling in Example 2 show that the structure of the material is not destroyed after cycling, and the Mo, S, C, and Co elements are still evenly distributed, further demonstrating the durability and stability of the dual-support C-Co-MoS2 single-atom catalyst.

[0059] Table 1: ICP-MS data of Co element in C-Co-MoS2

[0060]

[0061] Table 1 contains the ICP-MS data of Co in Example 2, and the results show that the mass percentage of Co is 1.58%. The above conclusions prove that the Co single atom is successfully inserted between the C and MoS2 layers to form a unique C-Co-S v Dual carrier active site.

[0062] Example 3

[0063] The preparation steps of egg yolk and eggshell structure C-MoS2 are the same as those in Example 1.

[0064] First, the egg yolk and eggshell structure C-MoS2 was uniformly dispersed in a mixed solution of 20 mL of deionized water and 80 mL of ethanol to prepare a solution with a concentration of 5 mg / mL; secondly, potassium hexacyanoferrous(II)ate was added to the above solution to prepare a solution concentration of 0.05 mmol / mL, stirred for 24 hours and then centrifuged and washed; the obtained product was then subjected to a gradient heat treatment with the specific parameters as follows: keeping the temperature at 200 °C in an argon tube furnace for 2 hours; heating to 750 °C and treating for 5 hours to obtain a dual-support C-Fe-MoS2 single-atom catalyst.

[0065] Figure 1 Including the dual-anchor model of the dual-support C-Fe-MoS2 single-atom catalyst in Example 3, density functional theory shows that the introduction of sulfur vacancies in MoS2 containing intercalated carbon can generate "electron locks" to capture negative ion metal groups and achieve in situ anchoring of metal single atoms; Figure 4 The XRD pattern of the dual-support C-Fe-MoS2 single-atom catalyst in Example 3 shows a broad peak of carbon and a typical peak of 2H-MoS2. The broad peak of the extended layer around 9.3° is contributed by both the intercalated carbon and the MoS2 (002) plane. The carbon peak is marked with ◆. Figure 6 This is the FESEM image of the dual-support C-Fe-MoS2 single-atom catalyst in Example 3, showing the monodisperse and uniform distribution of the material; Figure 14The TEM photo, HRTEM photo, low-magnification HAADF photo and corresponding EDS surface analysis photo of the dual-support C-Fe-MoS2 single-atom catalyst in Example 3, in which the HRTEM photo can be observed that the interlayer spacing is expanded from 0.62 nm to 0.96 nm due to the embedding of carbon (0.33 nm) in the (002) plane of MoS2, as well as the lattice fringes corresponding to the (100) plane of MoS2. The low-magnification HAADF and corresponding EDS surface analysis photos show that Mo, S, C, and Fe are also evenly distributed. The above results prove that Fe single atoms are successfully loaded on C-MoS2. The material was tested using a traditional three-electrode system. Figure 23 The polarization curve of the dual-support C-Fe-MoS2 single-atom catalyst in Example 3 shows an overpotential of 35 mV; Figure 24 The Tafel slope curve of the dual-support C-Fe-MoS2 single-atom catalyst in Example 3 is shown to be 44 mV / dec. Figure 25 The specific capacitance curve of the dual-support C-Fe-MoS2 single-atom catalyst in Example 3 shows a specific capacitance of 8.43 mF / cm 2 .

[0066] Example 4

[0067] The preparation steps of egg yolk and eggshell structure C-MoS2 are the same as those in Example 1.

[0068] First, the egg yolk and eggshell structure C-MoS2 was uniformly dispersed in a mixed solution of 20 mL of deionized water and 80 mL of ethanol to prepare a solution with a concentration of 5 mg / mL; secondly, potassium tetracyanonickel (II) hydrate was added to the above solution to prepare a solution concentration of 0.05 mmol / mL, stirred for 24 hours and then centrifuged and washed; the obtained product was then subjected to a gradient heat treatment with the specific parameters as follows: keeping the temperature at 200 °C in an argon tube furnace for 2 hours; heating to 750 °C and treating for 5 hours to obtain a dual-support C-Ni-MoS2 single-atom catalyst.

[0069] Figure 1 Including the dual-anchor model of the dual-support C-Ni-MoS2 single-atom catalyst in Example 4, density functional theory shows that the introduction of sulfur vacancies in MoS2 containing intercalated carbon can generate "electron locks" to capture negative ion metal groups and achieve in situ anchoring of metal single atoms; Figure 4 The XRD pattern of the dual-support C-Ni-MoS2 single-atom catalyst in Example 4 shows a broad peak of carbon and a typical peak of 2H-MoS2. The broad peak of the extended layer around 9.3° is contributed by the intercalated carbon and the MoS2 (002) plane. The carbon peak is marked with ◆. Figure 7This is the FESEM image of the dual-support C-Ni-MoS2 single-atom catalyst in Example 4, showing the monodisperse and uniform distribution of the material; Figure 15 The TEM photo, HRTEM photo, low-magnification HAADF photo and corresponding EDS surface analysis photo of the dual-support C-Ni-MoS2 single-atom catalyst in Example 4, in which the HRTEM photo can be observed that due to the embedding of carbon (0.33 nm) in the (002) plane of MoS2, the interlayer spacing is expanded from 0.62 nm to 0.96 nm and the obvious lattice fringes corresponding to the (100) plane of MoS2 are observed. The low-magnification HAADF and corresponding EDS surface analysis photos show that Mo, S, C, and Ni are also evenly distributed. The above results prove that Ni single atoms are successfully loaded on C-MoS2. The material was tested using a traditional three-electrode system. Figure 23 The polarization curve of the dual-support C-Ni-MoS2 single-atom catalyst in Example 4 shows an overpotential of 152 mV; Figure 24 The Tafel slope curve of the dual-support C-Ni-MoS2 single-atom catalyst in Example 4 is shown to be 113 mV / dec. Figure 25 The specific capacitance curve of the dual-support C-Ni-MoS2 single-atom catalyst in Example 4 shows a specific capacitance of 4.79 mF / cm 2 .

[0070] Table 2: ICP-MS data of Ni element in C-Ni-MoS2

[0071]

[0072] Table 2 contains the ICP-MS data of Ni in Example 4, which shows that the mass percentage of Ni is 1.52%.

[0073] Example 5

[0074] The preparation steps of egg yolk and eggshell structure C-MoS2 are the same as those in Example 1.

[0075] First, the egg yolk and eggshell structure C-MoS2 was uniformly dispersed in a mixed solution of 20 mL of deionized water and 80 mL of ethanol to prepare a solution with a concentration of 5 mg / mL; secondly, lithium tetrachlorocuprate was added to the above solution to prepare a solution concentration of 0.05 mmol / mL, stirred for 24 hours and then centrifuged and washed; the obtained product was then subjected to gradient heat treatment, with the specific parameters being: keeping the temperature at 200 °C in an argon tube furnace for 2 hours; heating to 750 °C and treating for 5 hours to obtain the C-Cu-MoS2 dual-support single-atom catalyst.

[0076] Figure 1Including the dual-anchor model of the dual-support C-Cu-MoS2 single-atom catalyst in Example 5, density functional theory shows that the introduction of sulfur vacancies in MoS2 containing intercalated carbon can generate "electron locks" to capture negative ion metal groups and achieve in situ anchoring of metal single atoms; Figure 4 The XRD pattern of the dual-support C-Cu-MoS2 single-atom catalyst in Example 5 shows a broad peak of carbon and a typical peak of 2H-MoS2. The broad peak of the extended layer around 9.3° is contributed by the intercalated carbon and the MoS2 (002) plane. The carbon peak is marked with ◆. Figure 8 This is the FESEM image of the dual-support C-Cu-MoS2 single-atom catalyst in Example 5, showing the monodisperse and uniform distribution of the material; Figure 16 The TEM photo, HRTEM photo, low-magnification HAADF photo and corresponding EDS surface analysis photo of the dual-support C-Cu-MoS2 single-atom catalyst in Example 5, in which the HRTEM photo can be observed that the interlayer spacing is expanded from 0.62 nm to 0.96 nm due to the embedding of carbon (0.33 nm) in the (002) plane of MoS2, as well as the lattice fringes corresponding to the (100) plane of MoS2. The low-magnification HAADF and corresponding EDS surface analysis photos show that Mo, S, C, and Cu are also evenly distributed. The above results prove that Cu single atoms are successfully loaded on C-MoS2. The material was tested using a traditional three-electrode system. Figure 23 The polarization curve of the dual-support C-Cu-MoS2 single-atom catalyst in Example 4 was included, and the results showed an overpotential of 80 mV; Figure 24 The Tafel slope curve of the dual-support C-Cu-MoS2 single-atom catalyst in Example 4 is included, and the results show that the Tafel slope is 73 mV / dec; Figure 25 The specific capacitance curve of the dual-support C-Cu-MoS2 single-atom catalyst in Example 4 shows a specific capacitance of 6.31 mF / cm 2 .

[0077] Table 3: ICP-MS data of Cu element in C-Cu-MoS2

[0078]

[0079] Table 3 contains the ICP-MS data of Cu in Example 5, which shows that the mass percentage of Cu is 1.31%.

[0080] Example 6

[0081] The preparation steps of egg yolk and eggshell structure C-MoS2 are the same as those in Example 1.

[0082] First, the egg yolk and eggshell structure C-MoS2 was uniformly dispersed in a mixed solution of 20 mL of deionized water and 80 mL of ethanol to prepare a solution with a concentration of 5 mg / mL; secondly, sodium zinc tetrahydroxide was added to the above solution to prepare a solution concentration of 0.05 mmol / mL, stirred for 24 hours and then centrifuged and washed; the obtained product was then subjected to a gradient heat treatment with the specific parameters: keeping it at 200 °C in argon in a tubular furnace for 2 hours; heating to 750 °C and treating for 5 hours to obtain a dual-support C-Zn-MoS2 single-atom catalyst.

[0083] Figure 1 Including the dual-anchor model of the dual-support C-Zn-MoS2 single-atom catalyst in Example 6, density functional theory shows that the introduction of sulfur vacancies in MoS2 containing intercalated carbon can generate "electron locks" to capture negative ion metal groups and achieve in situ anchoring of metal single atoms; Figure 4 The XRD pattern of the dual-support C-Zn-MoS2 single-atom catalyst in Example 6 shows a broad peak of carbon and a typical peak of 2H-MoS2. The broad peak of the extended layer around 9.3° is contributed by both the intercalated carbon and the MoS2 (002) plane. The carbon peak is marked with ◆. Figure 9 This is the FESEM image of the dual-support C-Zn-MoS2 single-atom catalyst in Example 6, showing the monodisperse and uniform distribution of the material; Figure 17 The following are the TEM photos, HRTEM photos, spherical aberration electron microscopy photos, low-magnification HAADF photos, and corresponding EDS surface analysis photos of the dual-support C-Zn-MoS2 single-atom catalyst in Example 6. In the HRTEM photos, it can be observed that due to the embedding of carbon (0.33 nm) in the (002) plane of MoS2, the interlayer spacing is expanded from 0.62 nm to 0.96 nm, as well as the lattice fringes corresponding to the (100) plane of MoS2. The low-magnification HAADF and corresponding EDS surface analysis photos show that Mo, S, C, and Zn are also uniformly distributed. The above results prove that Zn single atoms are successfully loaded on C-MoS2. The material was tested using a traditional three-electrode system. Figure 23 The polarization curve of the dual-support C-Zn-MoS2 single-atom catalyst in Example 6 shows an overpotential of 114 mV; Figure 24 The Tafel slope curve of the dual-support C-Zn-MoS2 single-atom catalyst in Example 6 is included, and the results show that the Tafel slope is 89 mV / dec; Figure 25 The specific capacitance curve of the dual-support C-Zn-MoS2 single-atom catalyst in Example 6 shows a specific capacitance of 5.08 mF / cm 2 .

[0084] Example 7

[0085] The preparation steps of egg yolk and eggshell structure C-MoS2 are the same as those in Example 1.

[0086] First, the egg yolk and eggshell structure C-MoS2 was uniformly dispersed in a mixed solution of 20 mL of deionized water and 80 mL of ethanol to prepare a solution with a concentration of 5 mg / mL; secondly, sodium permanganate monohydrate was added to the above solution to prepare a solution concentration of 0.05 mmol / mL, stirred for 24 hours and then centrifuged and washed; the obtained product was then subjected to gradient heat treatment with the specific parameters: keeping it warm at 200 °C in an argon tube furnace for 2 hours; heating to 750 °C and treating for 5 hours to obtain a dual-support C-Mn-MoS2 single-atom catalyst.

[0087] Figure 1 Including the dual-anchor model of the dual-support C-Mn-MoS2 single-atom catalyst in Example 7, density functional theory shows that the introduction of sulfur vacancies in MoS2 containing intercalated carbon can generate "electron locks" to capture negative ion metal groups and achieve in-situ anchoring of metal single atoms; Figure 4 The XRD pattern of the dual-support C-Mn-MoS2 single-atom catalyst in Example 7 shows a broad peak of carbon and a typical peak of 2H-MoS2. The broad peak of the extended layer around 9.3° is contributed by the intercalated carbon and the MoS2 (002) plane. The carbon peak is marked with ◆. Figure 10 This is the FESEM image of the C-Mn-MoS2 dual-support single-atom catalyst in Example 7, showing the monodisperse and uniform distribution of the material; Figure 18 The TEM photo, HRTEM photo, low-magnification HAADF photo and corresponding EDS surface analysis photo of the dual-support C-Mn-MoS2 single-atom catalyst in Example 7, in which the HRTEM photo can be observed that the interlayer spacing is expanded from 0.62 nm to 0.96 nm due to the embedding of carbon (0.33 nm) in the (002) plane of MoS2, as well as the lattice fringes corresponding to the (100) plane of MoS2. The low-magnification HAADF and corresponding EDS surface analysis photos show that Mo, S, C, and Mn are also uniformly distributed. The above results prove that the Mn single atom is successfully loaded on C-MoS2. The material was tested using a traditional three-electrode system. Figure 23 The polarization curve of the dual-support C-Mn-MoS2 single-atom catalyst in Example 6 shows an overpotential of 185 mV; Figure 24 The Tafel slope curve of the dual-support C-Mn-MoS2 single-atom catalyst in Example 7 is included, and the results show that the Tafel slope is 137 mV / dec; Figure 25 The specific capacitance curve of the dual-support C-Mn-MoS2 single-atom catalyst in Example 7 shows a specific capacitance of 3.85 mF / cm 2 .

[0088] Example 8

[0089] The preparation steps of egg yolk and eggshell structure C-MoS2 are the same as those in Example 1.

[0090] First, the egg yolk and eggshell structure C-MoS2 was uniformly dispersed in a mixed solution of 20 mL of deionized water and 80 mL of ethanol to prepare a solution with a concentration of 5 mg / mL; secondly, potassium cadmium cyanide was added to the above solution to prepare a solution concentration of 0.05 mmol / mL, stirred for 24 hours and then centrifuged and washed; the obtained product was then subjected to gradient heat treatment, with the specific parameters as follows: keeping the temperature at 200 °C in an argon tube furnace for 2 hours; heating to 750 °C and treating for 5 hours to obtain a dual-support C-Cd-MoS2 single-atom catalyst.

[0091] Figure 1 Including the dual-anchor model of the dual-support C-Cd-MoS2 single-atom catalyst in Example 8, density functional theory shows that the introduction of sulfur vacancies in MoS2 containing intercalated carbon can generate "electron locks" to capture negative ion metal groups and achieve in situ anchoring of metal single atoms; Figure 4 The XRD pattern of the dual-support C-Cd-MoS2 single-atom catalyst in Example 8 shows a broad peak of carbon and a typical peak of 2H-MoS2. The broad peak of the extended layer around 9.3° is contributed by the intercalated carbon and the MoS2 (002) plane. The carbon peak is marked with ◆. Figure 11 This is the FESEM image of the C-Cd-MoS2 dual-support single-atom catalyst in Example 8, showing the monodisperse and uniform distribution of the material; Figure 19 The TEM photo, HRTEM photo, low-magnification HAADF photo and corresponding EDS surface analysis photo of the dual-support C-Cd-MoS2 single-atom catalyst in Example 8, in which the HRTEM photo can be observed that due to the embedding of carbon (0.33 nm) in the (002) plane of MoS2, the interlayer spacing is expanded from 0.62 nm to 0.96 nm, as well as the lattice fringes corresponding to the (100) plane of MoS2. The low-magnification HAADF and corresponding EDS surface analysis photos show that Mo, S, C, and Cd are also uniformly distributed. The above results prove that Cd single atoms are successfully loaded on C-MoS2. The material was tested using a traditional three-electrode system. Figure 23 The polarization curve of the dual-support C-Cd-MoS2 single-atom catalyst in Example 6 was included, and the results showed an overpotential of 185 mV; Figure 24 The Tafel slope curve of the dual-support C-Cd-MoS2 single-atom catalyst in Example 7 is included, and the results show that the Tafel slope is 137mV / dec; Figure 25 The specific capacitance curve of the dual-support C-Cd-MoS2 single-atom catalyst in Example 7 shows a specific capacitance of 3.85 mF / cm 2 .

[0092] Example 9

[0093] The preparation steps of egg yolk and eggshell structure C-MoS2 are the same as those in Example 1.

[0094] First, the egg yolk and eggshell structure C-MoS2 was uniformly dispersed in a mixed solution of 20 mL of deionized water and 80 mL of ethanol to prepare a solution with a concentration of 5 mg / mL; secondly, sodium tungstate dihydrate was added to the above solution to prepare a solution concentration of 0.05 mmol / mL, stirred for 24 hours and then centrifuged and washed; the obtained product was then subjected to a gradient heat treatment with the specific parameters: keeping the temperature at 200 °C in an argon tube furnace for 2 hours; heating to 750 °C and treating for 5 hours to obtain a dual-support CW-MoS2 single-atom catalyst.

[0095] Figure 1 Including the dual-anchor model of the dual-support CW-MoS2 single-atom catalyst in Example 9, density functional theory shows that the introduction of sulfur vacancies in MoS2 containing intercalated carbon can generate "electron locks" to capture negative ion metal groups and achieve in situ anchoring of metal single atoms; Figure 4 The XRD pattern of the dual-support CW-MoS2 single-atom catalyst in Example 9 shows a broad peak of carbon and a typical peak of 2H-MoS2. The broad peak of the extended layer around 9.3° is contributed by the intercalated carbon and the MoS2 (002) plane. The carbon peak is marked with ◆. Figure 12 This is the FESEM image of the CW-MoS2 dual-support single-atom catalyst in Example 9, showing the monodisperse and uniform distribution of the material; Figure 20 The TEM photo, HRTEM photo, low-magnification HAADF photo and corresponding EDS surface analysis photo of the dual-support CW-MoS2 single-atom catalyst in Example 9. Among them, the HRTEM photo shows that due to the embedding of carbon (0.33 nm) in the (002) plane of MoS2, the interlayer spacing is expanded from 0.62 nm to 0.96 nm, as well as the lattice fringes corresponding to the (100) plane of MoS2. The low-magnification HAADF and corresponding EDS surface analysis photos show that Mo, S, C, and W are also evenly distributed. The above results prove that W single atoms are successfully loaded on C-MoS2. The material was tested using a traditional three-electrode system. Figure 23 The polarization curve of the dual-support CW-MoS2 single-atom catalyst in Example 9 shows an overpotential of 71 mV; Figure 24 The Tafel slope curve of the dual-support CW-MoS2 single-atom catalyst in Example 9 shows that the Tafel slope is 70 mV / dec; Figure 25 The specific capacitance curve of the dual-support CW-MoS2 single-atom catalyst in Example 9 shows a specific capacitance of 7.2 mF / cm 2 .

[0096] Table 4: ICP-MS data of W element in CW-MoS2

[0097]

[0098] Table 4 contains the ICP-MS data of W in Example 9, which shows that the mass percentage of W is 1.41%.

[0099] Example 10

[0100] The preparation steps of egg yolk and eggshell structure C-MoS2 are the same as those in Example 1.

[0101] First, the egg yolk and eggshell structure C-MoS2 was uniformly dispersed in a mixed solution of 15 mL of deionized water and 80 mL of ethanol to prepare a solution with a concentration of 10 mg / mL; secondly, potassium hexacyanocobaltate (III) was added to the above solution to prepare a solution concentration of 0.1 mmol / mL, stirred for 24 hours and then centrifuged and washed; the obtained product was then subjected to a gradient heat treatment with the specific parameters as follows: keeping it warm at 250°C in an argon tube furnace for 1 hour; heating to 850°C and treating for 1 hour to obtain a dual-support C-Co-MoS2 single-atom catalyst.

[0102] Table 1 contains the ICP-MS data of Co in Example 10, which shows that the mass percentage of Co is 5.71%.

[0103] Example 11

[0104] The preparation steps of egg yolk and eggshell structure C-MoS2 are the same as those in Example 1.

[0105] First, the egg yolk and eggshell structure C-MoS2 was uniformly dispersed in a mixed solution of 10 mL of deionized water and 80 mL of ethanol to prepare a solution with a concentration of 8 mg / mL; secondly, potassium hexacyanocobaltate (III) was added to the above solution to prepare a solution concentration of 0.08 mmol / mL, stirred for 24 hours and then centrifuged and washed; the obtained product was then subjected to a gradient heat treatment with the specific parameters as follows: keeping it warm at 220°C in an argon tube furnace for 1.5 hours; heating to 800°C and treating for 3 hours to obtain a dual-support C-Co-MoS2 single-atom catalyst.

[0106] Table 1 contains the ICP-MS data of Co in Example 11, which shows that the mass percentage of Co is 2.57%.

[0107] Example 12

[0108] The preparation steps of egg yolk and eggshell structure C-MoS2 are the same as those in Example 1.

[0109] First, the egg yolk and eggshell structure C-MoS2 was uniformly dispersed in a mixed solution of 5 mL of deionized water and 80 mL of ethanol to prepare a solution with a concentration of 1 mg / mL; secondly, potassium hexacyanocobaltate (III) was added to the above solution to prepare a solution concentration of 0.01 mmol / mL, stirred for 24 hours and then centrifuged and washed; the obtained product was then subjected to a gradient heat treatment with the specific parameters as follows: keeping the temperature at 180°C in an argon tube furnace for 2.5 hours; heating to 700°C and treating for 7 hours to obtain a dual-support C-Co-MoS2 single-atom catalyst.

[0110] Table 1 contains the ICP-MS data of Co in Example 12, which shows that the mass percentage of Co is 0.77%.

[0111] Example 13

[0112] The preparation steps of egg yolk and eggshell structure C-MoS2 are the same as those in Example 1.

[0113] First, the egg yolk and eggshell structure C-MoS2 was uniformly dispersed in a mixed solution of 1 mL of deionized water and 80 mL of ethanol to prepare a solution with a concentration of 0.1 mg / mL; secondly, potassium hexacyanocobaltate (III) was added to the above solution to prepare a solution concentration of 0.001 mmol / mL, stirred for 24 hours and then centrifuged and washed; the obtained product was then subjected to a gradient heat treatment with the specific parameters as follows: keeping the temperature at 160°C in an argon tube furnace for 3 hours; heating to 650°C and treating for 9 hours to obtain a dual-support C-Co-MoS2 single-atom catalyst.

[0114] Example 14

[0115] The preparation steps of egg yolk and eggshell structure C-MoS2 are the same as those in Example 1.

[0116] First, the egg yolk and eggshell structure C-MoS2 was uniformly dispersed in a mixed solution of 15 mL of deionized water and 80 mL of ethanol to prepare a solution with a concentration of 10 mg / mL; secondly, potassium tetracyanonickel (II) hydrate was added to the above solution to prepare a solution concentration of 0.1 mmol / mL, stirred for 24 hours and then centrifuged and washed; the obtained product was then subjected to a gradient heat treatment with the specific parameters: keeping it warm at 250°C in an argon tube furnace for 1 hour; heating to 850°C and treating for 1 hour to obtain a dual-support C-Ni-MoS2 single-atom catalyst.

[0117] Table 2 contains the ICP-MS data of Ni in Example 14, which shows that the mass percentage of Ni is 5.27%.

[0118] Example 15

[0119] The preparation steps of egg yolk and eggshell structure C-MoS2 are the same as those in Example 1.

[0120] First, the egg yolk and eggshell structure C-MoS2 was uniformly dispersed in a mixed solution of 10 mL of deionized water and 80 mL of ethanol to prepare a solution with a concentration of 8 mg / mL; secondly, potassium tetracyanonickel (II) hydrate was added to the above solution to prepare a solution concentration of 0.08 mmol / mL, stirred for 24 hours and then centrifuged and washed; the obtained product was then subjected to a gradient heat treatment with the specific parameters as follows: keeping it warm at 220°C in an argon tube furnace for 1.5 hours; heating to 800°C and treating for 3 hours to obtain a dual-support C-Ni-MoS2 single-atom catalyst.

[0121] Table 2 contains the ICP-MS data of Ni in Example 15, which shows that the mass percentage of Ni is 2.37%.

[0122] Example 16

[0123] The preparation steps of egg yolk and eggshell structure C-MoS2 are the same as those in Example 1.

[0124] First, the egg yolk and eggshell structure C-MoS2 was uniformly dispersed in a mixed solution of 5 mL of deionized water and 80 mL of ethanol to prepare a solution with a concentration of 1 mg / mL; secondly, potassium tetracyanonickel (II) hydrate was added to the above solution to prepare a solution concentration of 0.01 mmol / mL, stirred for 24 hours and then centrifuged and washed; the obtained product was then subjected to gradient heat treatment with the specific parameters as follows: keeping the temperature at 180 °C in an argon tube furnace for 2.5 hours; heating to 700 °C and treating for 7 hours to obtain a dual-support C-Ni-MoS2 single-atom catalyst.

[0125] Table 2 contains the ICP-MS data of Ni in Example 16, which shows that the mass percentage of Ni is 0.83%.

[0126] Example 17

[0127] The preparation steps of egg yolk and eggshell structure C-MoS2 are the same as those in Example 1.

[0128] First, the egg yolk and eggshell structure C-MoS2 was uniformly dispersed in a mixed solution of 1 mL of deionized water and 80 mL of ethanol to prepare a solution with a concentration of 0.1 mg / mL; secondly, potassium tetracyanonickel (II) hydrate was added to the above solution to prepare a solution concentration of 0.001 mmol / mL, stirred for 24 hours and then centrifuged and washed; the obtained product was then subjected to a gradient heat treatment with the specific parameters as follows: keeping the temperature at 160°C in an argon tube furnace for 3 hours; heating to 650°C and treating for 9 hours to obtain a dual-support C-Ni-MoS2 single-atom catalyst.

[0129] Example 18

[0130] The preparation steps of egg yolk and eggshell structure C-MoS2 are the same as those in Example 1.

[0131] First, the egg yolk and eggshell structure C-MoS2 was uniformly dispersed in a mixed solution of 15 mL of deionized water and 80 mL of ethanol to prepare a solution with a concentration of 10 mg / mL; secondly, lithium tetrachlorocuprate was added to the above solution to prepare a solution concentration of 0.1 mmol / mL, stirred for 24 hours and then centrifuged and washed; the obtained product was then subjected to gradient heat treatment, with the specific parameters being: keeping the temperature at 250°C in an argon tube furnace for 1 hour; heating to 850°C and treating for 1 hour to obtain a dual-support C-Cu-MoS2 single-atom catalyst.

[0132] Table 3 contains the ICP-MS data of Cu in Example 18, which shows that the mass percentage of Cu is 4.27%.

[0133] Example 19

[0134] The preparation steps of egg yolk and eggshell structure C-MoS2 are the same as those in Example 1.

[0135] First, the egg yolk and eggshell structure C-MoS2 was uniformly dispersed in a mixed solution of 10 mL of deionized water and 80 mL of ethanol to prepare a solution with a concentration of 8 mg / mL; secondly, lithium tetrachlorocuprate was added to the above solution to prepare a solution concentration of 0.08 mmol / mL, stirred for 24 hours and then centrifuged and washed; the obtained product was then subjected to gradient heat treatment, with the specific parameters as follows: keeping the temperature at 220°C in an argon tube furnace for 1.5 hours; heating to 800°C and treating for 3 hours to obtain a dual-support C-Cu-MoS2 single-atom catalyst.

[0136] Table 3 contains the ICP-MS data of Cu in Example 19, which shows that the mass percentage of Cu is 1.98%.

[0137] Example 20

[0138] The preparation steps of egg yolk and eggshell structure C-MoS2 are the same as those in Example 1.

[0139] First, the egg yolk and eggshell structure C-MoS2 was uniformly dispersed in a mixed solution of 5 mL of deionized water and 80 mL of ethanol to prepare a solution with a concentration of 1 mg / mL; secondly, lithium tetrachlorocuprate was added to the above solution to prepare a solution concentration of 0.01 mmol / mL, stirred for 24 hours and then centrifuged and washed; the obtained product was then subjected to gradient heat treatment, with the specific parameters as follows: keeping the temperature at 180°C in an argon tube furnace for 2.5 hours; heating to 700°C and treating for 7 hours to obtain a dual-support C-Cu-MoS2 single-atom catalyst.

[0140] Table 3 contains the ICP-MS data of Cu in Example 20, which shows that the mass percentage of Cu is 0.51%.

[0141] Example 21

[0142] The preparation steps of egg yolk and eggshell structure C-MoS2 are the same as those in Example 1.

[0143] First, the egg yolk and eggshell structure C-MoS2 was uniformly dispersed in a mixed solution of 1 mL of deionized water and 80 mL of ethanol to prepare a solution with a concentration of 0.1 mg / mL; secondly, lithium tetrachlorocuprate was added to the above solution to prepare a solution concentration of 0.001 mmol / mL, stirred for 24 hours and then centrifuged and washed; the obtained product was then subjected to a gradient heat treatment with the specific parameters: keeping the temperature at 160°C in an argon tube furnace for 3 hours; heating to 650°C and treating for 9 hours to obtain a dual-support C-Cu-MoS2 single-atom catalyst.

[0144] Example 22

[0145] The preparation steps of egg yolk and eggshell structure C-MoS2 are the same as those in Example 1.

[0146] First, the egg yolk and eggshell structure C-MoS2 was uniformly dispersed in a mixed solution of 15 mL of deionized water and 80 mL of ethanol to prepare a solution with a concentration of 10 mg / mL; secondly, sodium tungstate dihydrate was added to the above solution to prepare a solution concentration of 0.1 mmol / mL, stirred for 24 hours and then centrifuged and washed; the obtained product was then subjected to a gradient heat treatment with the specific parameters as follows: keeping the temperature at 250°C in an argon tube furnace for 1 hour; heating to 850°C and treating for 1 hour to obtain a dual-support CW-MoS2 single-atom catalyst.

[0147] Table 4 contains the ICP-MS data of W in Example 22, which shows that the mass percentage of W is 4.75%.

[0148] Example 23

[0149] The preparation steps of egg yolk and eggshell structure C-MoS2 are the same as those in Example 1.

[0150] First, the egg yolk and eggshell structure C-MoS2 was uniformly dispersed in a mixed solution of 10 mL of deionized water and 80 mL of ethanol to prepare a solution with a concentration of 8 mg / mL; secondly, sodium tungstate dihydrate was added to the above solution to prepare a solution concentration of 0.08 mmol / mL, stirred for 24 hours and then centrifuged and washed; the obtained product was then subjected to a gradient heat treatment with the specific parameters as follows: keeping it at 220°C in an argon tube furnace for 1.5 hours; heating to 800°C and treating for 3 hours to obtain a dual-support CW-MoS2 single-atom catalyst.

[0151] Table 4 contains the ICP-MS data of W in Example 23, which shows that the mass percentage of W is 2.23%.

[0152] Example 24

[0153] The preparation steps of egg yolk and eggshell structure C-MoS2 are the same as those in Example 1.

[0154] First, the egg yolk and eggshell structure C-MoS2 was uniformly dispersed in a mixed solution of 5 mL of deionized water and 80 mL of ethanol to prepare a solution with a concentration of 1 mg / mL; secondly, sodium tungstate dihydrate was added to the above solution to prepare a solution concentration of 0.01 mmol / mL, stirred for 24 hours and then centrifuged and washed; the obtained product was then subjected to a gradient heat treatment with the specific parameters as follows: keeping the temperature at 180°C in an argon tube furnace for 2.5 hours; heating to 700°C and treating for 7 hours to obtain a dual-support CW-MoS2 single-atom catalyst.

[0155] Table 4 contains the ICP-MS data of W in Example 24, which shows that the mass percentage of W is 0.58%.

[0156] Example 25

[0157] The preparation steps of egg yolk and eggshell structure C-MoS2 are the same as those in Example 1.

[0158] First, the egg yolk and eggshell structure C-MoS2 was uniformly dispersed in a mixed solution of 1 mL of deionized water and 80 mL of ethanol to prepare a solution with a concentration of 0.1 mg / mL; secondly, sodium tungstate dihydrate was added to the above solution to prepare a solution concentration of 0.001 mmol / mL, stirred for 24 hours and then centrifuged and washed; the obtained product was then subjected to a gradient heat treatment with the specific parameters as follows: keeping the temperature at 160°C in an argon tube furnace for 3 hours; heating to 650°C and treating for 9 hours to obtain a dual-support CW-MoS2 single-atom catalyst.

[0159] Example 26

[0160] The preparation steps of egg yolk and eggshell structure C-MoS2 are the same as those in Example 1.

[0161] First, the egg yolk and eggshell structure C-MoS2 was uniformly dispersed in a mixed solution of 15 mL of deionized water and 80 mL of ethanol to prepare a solution with a concentration of 10 mg / mL; secondly, potassium hexacyanoferrous(II)ate was added to the above solution to prepare a solution concentration of 0.1 mmol / mL, stirred for 24 hours and then centrifuged and washed; the obtained product was then subjected to a gradient heat treatment with the specific parameters as follows: keeping the temperature at 250 °C in an argon tube furnace for 1 hour; heating to 850 °C and treating for 1 hour to obtain a dual-support C-Fe-MoS2 single-atom catalyst.

[0162] Example 27

[0163] The preparation steps of egg yolk and eggshell structure C-MoS2 are the same as those in Example 1.

[0164] First, the egg yolk and eggshell structure C-MoS2 was uniformly dispersed in a mixed solution of 1 mL of deionized water and 80 mL of ethanol to prepare a solution with a concentration of 0.1 mg / mL; secondly, potassium hexacyanoferrous(II) acid was added to the above solution to prepare a solution concentration of 0.001 mmol / mL, stirred for 24 hours and then centrifuged and washed; the obtained product was then subjected to a gradient heat treatment with the specific parameters as follows: keeping the temperature at 160°C in an argon tube furnace for 3 hours; heating to 650°C and treating for 9 hours to obtain a dual-support C-Fe-MoS2 single-atom catalyst.

[0165] Example 28

[0166] The preparation steps of egg yolk and eggshell structure C-MoS2 are the same as those in Example 1.

[0167] First, the egg yolk and eggshell structure C-MoS2 was uniformly dispersed in a mixed solution of 15 mL of deionized water and 80 mL of ethanol to prepare a solution with a concentration of 10 mg / mL; secondly, sodium zinc tetrahydroxide was added to the above solution to prepare a solution concentration of 0.1 mmol / mL, stirred for 24 hours and then centrifuged and washed; the obtained product was then subjected to gradient heat treatment with the specific parameters: keeping it warm at 250°C in an argon tube furnace for 1 hour; heating to 850°C and treating for 1 hour to obtain a dual-support C-Zn-MoS2 single-atom catalyst.

[0168] Example 29

[0169] The preparation steps of egg yolk and eggshell structure C-MoS2 are the same as those in Example 1.

[0170] First, the egg yolk and eggshell structure C-MoS2 was uniformly dispersed in a mixed solution of 1 mL of deionized water and 80 mL of ethanol to prepare a solution with a concentration of 0.1 mg / mL; secondly, sodium tetrahydroxide zincate was added to the above solution to prepare a solution concentration of 0.001 mmol / mL, stirred for 24 hours and then centrifuged and washed; the obtained product was then subjected to a gradient heat treatment with the specific parameters as follows: keeping the temperature at 160°C in an argon tube furnace for 3 hours; heating to 650°C and treating for 9 hours to obtain a dual-support C-Zn-MoS2 single-atom catalyst.

[0171] Example 30

[0172] The preparation steps of egg yolk and eggshell structure C-MoS2 are the same as those in Example 1.

[0173] First, the egg yolk and eggshell structure C-MoS2 was uniformly dispersed in a mixed solution of 15 mL of deionized water and 80 mL of ethanol to prepare a solution with a concentration of 10 mg / mL; secondly, sodium permanganate monohydrate was added to the above solution to prepare a solution concentration of 0.1 mmol / mL, stirred for 24 hours and then centrifuged and washed; the obtained product was then subjected to gradient heat treatment with the specific parameters: keeping it warm at 250°C in an argon tube furnace for 1 hour; heating to 850°C and treating for 1 hour to obtain a dual-support C-Mn-MoS2 single-atom catalyst.

[0174] Example 31

[0175] The preparation steps of egg yolk and eggshell structure C-MoS2 are the same as those in Example 1.

[0176] First, the egg yolk and eggshell structure C-MoS2 was uniformly dispersed in a mixed solution of 1 mL of deionized water and 80 mL of ethanol to prepare a solution with a concentration of 0.1 mg / mL; secondly, sodium permanganate monohydrate was added to the above solution to prepare a solution concentration of 0.001 mmol / mL, stirred for 24 hours and then centrifuged and washed; the obtained product was then subjected to a gradient heat treatment with the specific parameters as follows: keeping the temperature at 160°C in an argon tube furnace for 3 hours; heating to 650°C and treating for 9 hours to obtain a dual-support C-Mn-MoS2 single-atom catalyst.

[0177] Example 32

[0178] The preparation steps of egg yolk and eggshell structure C-MoS2 are the same as those in Example 1.

[0179] First, the egg yolk and eggshell structure C-MoS2 was uniformly dispersed in a mixed solution of 15 mL of deionized water and 80 mL of ethanol to prepare a solution with a concentration of 10 mg / mL; secondly, potassium cadmium cyanide was added to the above solution to prepare a solution concentration of 0.1 mmol / mL, stirred for 24 hours and then centrifuged and washed; the obtained product was then subjected to gradient heat treatment, with the specific parameters as follows: keeping the temperature at 250°C in an argon tube furnace for 1 hour; heating to 850°C and treating for 1 hour to obtain a dual-support C-Cd-MoS2 single-atom catalyst.

[0180] Example 33

[0181] The preparation steps of egg yolk and eggshell structure C-MoS2 are the same as those in Example 1.

[0182] First, the egg yolk and eggshell structure C-MoS2 was uniformly dispersed in a mixed solution of 1 mL of deionized water and 80 mL of ethanol to prepare a solution with a concentration of 0.1 mg / mL; secondly, potassium cadmium cyanide was added to the above solution to prepare a solution concentration of 0.001 mmol / mL, stirred for 24 hours and then centrifuged and washed; the obtained product was then subjected to a gradient heat treatment with the specific parameters: keeping the temperature at 160°C in an argon tube furnace for 3 hours; heating to 650°C and treating for 9 hours to obtain a dual-support C-Cd-MoS2 single-atom catalyst.

[0183] Implementation effect examples

[0184] The material was tested using a traditional three-electrode system. The dual-support CM-MoS2 single-atom catalyst prepared in Example 2-9 was subjected to an acidic electrochemical hydrogen evolution test. The performance diagram is shown in FIG. Figure 23-25 As shown, Figure 23 is the polarization curve, Figure 24 is the Tafel curve, Figure 25 The results show that the overpotential and Tafel slope of the dual-support C-Co-MoS2 single-atom catalyst are as low as 17 mV (10 mA / cm 2 ) and 32 mV / dec, with a specific capacitance of up to 9.25 mF / cm 2 , which is superior to other dual-support CM-MoS2 single-atom catalysts. In addition, Figure 25 The catalyst was shown to be stable at different current densities (10 mA / cm 2 , 20mA / cm 2 , 50 mA / cm 2 , 100 mA / cm 2 ) showed a sustained and stable electrolysis capacity of 240 h. The above conclusions prove that the dual-support single-atom catalyst prepared by this invention has the application potential of energy-saving and stable water electrolysis to hydrogen production.

[0185] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a dual-support single-atom catalyst, characterized in that: Here are the steps: (1) Sodium molybdate dihydrate and glucose were dissolved in deionized water, and an aqueous solution was obtained by ultrasonication. A solution of hexadecyltrimethylammonium bromide in n-butanol was used as an oily solution. The aqueous solution was then added dropwise to the oily solution. After the first stirring, ethylene glycol and hydrochloric acid were added in sequence. After the second stirring, thiourea was added. After continued stirring, a two-step solvothermal reaction was performed to obtain a precursor. (2) The precursor of step (1) is subjected to gradient heat treatment to obtain dual-carrier C-MoS2, which is then dispersed in a mixed solution of deionized water and ethanol to obtain solution I; (3) adding a negative ion metal salt to solution I of step (2), stirring the reaction to obtain a precipitate, centrifuging and washing the obtained precipitate, and then subjecting it to a gradient heat treatment to obtain a dual-support single-atom catalyst; The negative ion metal salt in step (3) is any one of sodium permanganate monohydrate, potassium tetracyanonickel (II) hydrate, potassium hexacyanocobalt (III) acid, potassium hexacyanoferrous (II) acid, lithium tetrachlorocuprate, potassium cadmium cyanide, sodium zinc tetrahydrate or sodium tungstate dihydrate.

2. The method for preparing a dual-support single-atom catalyst according to claim 1, wherein: In step (1), the concentration of sodium molybdate dihydrate in the aqueous solution is 0.0033 mol / L, and the concentration of glucose is 0.0013 g / mL; the concentration of hexadecyltrimethylammonium bromide in the oil solution is 0.15 mol / L; the volume ratio of the aqueous solution, the oil solution, ethylene glycol, and hydrochloric acid is 300:100:50:0.7; and the molar ratio of sodium molybdate dihydrate to thiourea is 1:

12.

3. The method for preparing a dual-support single-atom catalyst according to claim 2, wherein: The two-step solvothermal reaction was carried out at 180°C for 4 h and then at 220°C for 20 h.

4. The method for preparing a dual-support single-atom catalyst according to claim 1, wherein: The conditions for the gradient heat treatment in step (2) are as follows: a heating rate of 2°C / min, maintaining at 200°C for 2 h, maintaining at 550°C for 2 h, and maintaining at 750°C for 5 h.

5. The method for preparing a dual-support single-atom catalyst according to claim 4, characterized in that: The volume ratio of deionized water to ethanol is (1-20):80; the concentration of the dual-carrier C-MoS2 in solution I is 0.1-10 mg / mL; the dual-carrier C-MoS2 has an egg-yolk-eggshell structure rich in sulfur vacancies and carbon intercalation.

6. The method for preparing a dual-support single-atom catalyst according to claim 1, wherein: The concentration of the negative ion metal salt is 0.001-0.1 mmol / mL.

7. The method for preparing a dual-support single-atom catalyst according to claim 6, characterized in that: The gradient heat treatment conditions are: maintaining the temperature at 160-250° C. for 1-3 h in an argon atmosphere, and then heating to 650-850° C. and maintaining the temperature for 1-9 h.

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