Preparation method and application of ruse2-co te / nc heterostructure electrocatalyst

Abstract

The application belongs to the field of electrocatalysis, and particularly relates to application of a RuSe2-CoTe / NC structure catalyst in electrolysis of water for hydrogen evolution under alkaline conditions. A MOF precursor is synthesized by a hydrothermal method, and then Te elements are introduced into the material by an anion exchange method. RuSe2 and the precursor containing Te elements are compounded by a hydrothermal method, and finally the MOF material is pyrolyzed into a carbon material, and the RuSe2-CoTe / NC electrocatalyst is obtained. The nitrogen-doped carbon material derived from the MOF material provides good conductivity and stability, and also increases active sites. The synergistic effect of RuSe2 and CoTe can further promote HER and improve the reaction performance. The synthesized RuSe2-CoTe / NC heterostructure catalyst has the advantages of simple synthesis operation, greenness and no pollution, and the catalyst has excellent electrolysis water hydrogen evolution performance and stability.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalyst preparation and application, specifically relating to the preparation and application of a RuSe2-CoTe / NC heterostructure catalyst. Technical Background

[0002] Based on the HER mechanism in alkaline media, excellent HER catalysts not only require adsorption of usable hydrogen intermediates (H*) and easy water dissociation to meet the high-efficiency application in water electrolysis for hydrogen evolution, but also need to meet economic requirements. From this perspective, Ru-based catalysts have greater potential than Pt-based catalysts because the optimized d-band electronic structure endows Ru with hydrogen binding ability similar to Pt, making it easier to dissociate in water, while its cost is only 1 / 10 of Pt, making it more economically viable. In particular, the modulation of metallic Ru by non-metallic anions such as P, S, and Se can accelerate the desorption rate of H to some extent. In addition, the abundant P, S, and Se sites in the material can optimize the electronic structure of catalytically active atoms, balance the hydrogen adsorption free energy, and promote the water dissociation process, thereby effectively reducing the HER barrier. However, single electronic structure modulation is not enough for Ru-based catalysts to be used on a large scale in practical applications, especially for RuSe2, where RuSe2 often exhibits poorer activity due to the lack of electrons in the active Ru atoms. Therefore, selecting an appropriate method to modulate the electrons of Ru atoms in RuSe2 can effectively improve the activity of the catalyst.

[0003] To effectively address these challenges, modifications are employed through heteroatom incorporation, interface manipulation, and defect engineering. Among these, modulating heterojunctions between different functional components has been widely established as a powerful means of electronic regulation, effectively inducing interfacial electron reconfiguration and altering the electronic state of active sites, thus accelerating charge transfer. Transition metal tellurides have recently been considered promising materials for electrochemical water splitting, supercapacitors, and ion batteries. Furthermore, the low electronegativity of transition metal tellurides makes them more likely to provide electrons with better conductivity, resulting in superior water splitting performance. While RuSe2 catalysts alone exhibit good HER performance, their overpotential is only 65 mV at calcination at 400 °C, and their stability requires further improvement due to electronic defects in Ru atoms. The synthesis of "RuSe2 / Co-NC nanocomposites and their application in hydrogen evolution under alkaline conditions" involved obtaining Co-NC materials through high-temperature calcination at 900 °C, followed by composite RuSe2 materials. However, the single sheet-like structure of Co-NC could not support sufficient RuSe2 material, hindering further improvements in hydrogen evolution applications. Furthermore, existing research on the preparation of CoTe / NF nanosheets employs a conventional hydrothermal method, where Te and cobalt sources are prepared in the presence of a reducing agent, which fails to expose sufficient active sites. Therefore, the purpose of this invention is to obtain a high-performance, highly stable RuSe2-CoTe / NC catalyst with abundant active sites, by constructing a heterostructure of CoTe and RuSe2 using MOF materials as precursors, thereby enabling it to exhibit excellent HER performance in alkaline electrolytes. Summary of the Invention

[0004] To address the problems in the background art, the present invention aims to provide a RuSe2-CoTe / NC heterostructure catalyst and its preparation method, and to apply it to the electrolysis of water in an alkaline environment to produce hydrogen, exhibiting excellent HER performance.

[0005] The technical solution of this invention: This invention provides a RuSe2-CoTe / NC heterostructure catalyst. The preparation method of this catalyst is as follows: First, a metal-organic framework (MOF) material containing Co is synthesized on a nickel foam substrate using a simple hydrothermal method. Then, the material is placed in a solution containing Te for anion exchange, introducing Te into the MOF material, resulting in an electrode of CoTe / NF. Subsequently, RuSe2 nanoparticles are loaded onto CoTe / NF via hydrothermal treatment. Finally, the electrode is placed in a tube furnace for carbonization pyrolysis, resulting in an electrocatalyst of RuSe2-CoTe / NC.

[0006] The specific process is as follows:

[0007] (1) Pretreatment of the nickel foam surface. CoCl2·6H2O was added to N,N-dimethylformamide (DMF), and then C8H7NO4 (Chinese name: 2-aminoterephthalic acid) was mixed into the solution. The uniformly mixed solution and the cleaned NF were placed in a polytetrafluoroethylene-lined autoclave for hydrothermal reaction. After the sample was washed and dried, it was placed in an aqueous sodium tellurite solution for anion exchange, followed by washing and drying. The obtained electrode was a CoTe / NF electrode.

[0008] The mass ratio of 2-aminoterephthalic acid to cobalt chloride hexahydrate was 1:1 to 1.5. The hydrothermal reaction temperature was 130℃, and the reaction time was 72 h. The concentration of sodium tellurite aqueous solution was 0.5 M to 1.5 M, and the anion exchange time was 12 h to 36 h.

[0009] (2) Then, a certain amount of selenium powder and ruthenium chloride were stirred vigorously for 120 min and dissolved in deionized water. Then, hydrazine hydrate was added to the reaction solution, and then transferred to a Teflon-lined autoclave. A CoTe / NF electrode was added to the autoclave for hydrothermal reaction. After the reaction, the washed and dried electrode was transferred to a tube furnace under a nitrogen atmosphere for annealing. The resulting electrode was a RuSe2-CoTe / NC electrode.

[0010] The molar ratio of ruthenium chloride to selenium powder is 1:2. The ratio of CoTe / NF electrode to selenium powder is 1 cm⁻¹. 2 5-20 mg. Hydrothermal temperature: 120℃, reaction time: 12 h. Annealing temperature: 300℃-500℃, heating rate: 5℃ / min. -1 The annealing time is 2 hours.

[0011] As a preferred method: 0.0098 g of selenium powder and 0.0129 g of ruthenium chloride were weighed and dissolved in deionized water after vigorous stirring for 120 min. Then, 1 mL of hydrazine hydrate was added to the reaction solution, and the mixture was transferred to a 50 mL Teflon-lined autoclave. A CoTe / NF electrode (1.0 cm × 1.0 cm) was added to the autoclave, and a hydrothermal reaction was carried out. The annealing temperature was 400 °C.

[0012] This invention synthesizes a MOF precursor using 2-aminoterephthalic acid as a ligand, cobalt chloride as the cobalt source, and nickel foam (NF) as a support via a hydrothermal method. Te element is then introduced into the material via anion exchange. RuSe2 and the Te-containing precursor are then combined hydrothermally, and finally, the MOF material is pyrolyzed in a tube furnace to obtain a RuSe2-CoTe / NC electrocatalyst while simultaneously converting the MOF material into a carbon material. By optimizing the concentration and time of anion exchange, the loading of RuSe2 on the electrode, and the annealing temperature, a RuSe2-CoTe / NC heterostructure electrocatalyst with optimal performance is obtained. Finally, the catalyst is applied to the electrolysis of water for hydrogen evolution under alkaline conditions.

[0013] The RuSe2-CoTe / NC heterostructure catalyst was used in a method for testing the electrocatalytic hydrogen evolution performance. A three-electrode system was employed: the working electrode was a RuSe2-CoTe / NC electrode, the counter electrode was a graphite rod electrode, the reference electrode was a Hg / HgO electrode, and the electrolyte was a 1 mol L⁻¹ solution. -1 KOH solution.

[0014] The technical effects achieved by this invention are:

[0015] (1) In this invention, a cobalt-containing MOF precursor is first prepared on nickel foam, and then CoTe / NF material is obtained through anion exchange. Under calcination, not only can RuSe2 material with good crystallinity be obtained, but the MOF material can also be converted into NC material to effectively coat CoTe and RuSe2 materials. Compared with CoTe / NF prepared by conventional hydrothermal method, the CoTe material synthesized in this invention will be interconnected with the C, N, and H of the MOF material. In the subsequent pyrolysis, a composite material coated with NC can be obtained. The NC layer not only plays a protective role, but the N element in it can play a good role in electronic modulation and further increase the wettability of the material, thereby increasing the contact with the solution. This makes the catalyst more stable. At the same time, it will also increase the interaction between CoTe and RuSe2. The RuSe2-CoTe / NC catalyst with heterostructure has high HER performance.

[0016] (2) This invention uses a heterostructure to compensate for the electronic defects of Ru atoms. The provided RuSe2-CoTe / NC heterostructure catalyst prepares a RuSe2-CoTe heterojunction with good interfacial synergy and an NC layer that plays a protective and supporting role. At the same time, the N element in the NC layer can further improve the performance of the material. Moreover, the synthesis method is simple and the synthesis process is green and pollution-free.

[0017] (3) The RuSe2-CoTe / NC heterostructure catalyst provided by the present invention is a sheet-like structure with small spherical particles supported. This structure can fully contact the heterostructure and the electrolyte, thereby promoting the reaction.

[0018] (4) The RuSe2-CoTe / NC heterostructure catalyst provided by this invention exhibits excellent HER performance in alkaline electrolytes. The HER performance is as follows: at -10 mA / cm²... -2 It exhibits an overpotential of -25.4mV at a given current density. Attached Figure Description

[0019] Figure 1 The XRD patterns of Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 are shown below.

[0020] Figure 2 The SEM image is from Example 1;

[0021] Figure 3 The EDS-Mapping map for Example 1;

[0022] Figure 4 The LSV spectra of Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 are shown below. Figure 5 Tafel spectra of Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3; Figure 6 The graph shows the 30-hour stability curve of Example 1. Detailed Implementation

[0023] The technical features of the present invention are further illustrated by the following examples, but the scope of protection of the present invention is not limited to the following embodiments.

[0024] Example 1

[0025] 1.1 mol L -1 Preparation of KOH solution

[0026] Dissolve 5.62 g of KOH in 50 mL of ultrapure water. After the KOH solution has completely dissolved and cooled, dilute to volume in a 100 mL volumetric flask.

[0027] 2. Preparation of Nickel Foam

[0028] A piece of nickel foam (NF, 1.0cm × 1.0cm) was immersed in 1M hydrochloric acid solution and sonicated for 10 minutes. The surface was then treated with acetone solution and sonicated for 10 minutes. Finally, it was sonicated with ethanol and ultrapure water for 20 minutes each.

[0029] 3. Preparation of CoTe / NF

[0030] NF slices (1.0 cm × 1.0 cm) were immersed in 1 M hydrochloric acid solution for 10 min, followed by sonication with acetone, ethanol, and ultrapure water for 20 min. 0.714 g of CoCl₂·6H₂O was added to 50 mL of DMF, and then 0.56 g of 2-aminoterephthalic acid (C₈H₇NO₄) was mixed into the solution. The homogeneous solution and the cleaned NF (1.0 cm × 1.0 cm) were placed in a 100 mL polytetrafluoroethylene-lined autoclave and maintained at 130 °C for 72 h. After washing and drying, the sample was placed in a 1 M sodium tellurite aqueous solution for anion exchange for 24 h, followed by washing and drying. The obtained catalyst was CoTe / NF.

[0031] 4. Preparation of RuSe2-CoTe / NC

[0032] First, 0.0098 g of selenium powder and 0.0129 g of ruthenium chloride were dissolved in the solution after vigorous stirring for 120 min. Then, 1 mL of hydrazine hydrate was added to the reaction solution, and the mixture was transferred to a 50 mL Teflon-lined autoclave. A CoTe / NF electrode (1.0 cm × 1.0 cm) was added to the autoclave, and the mixture was kept at 120 °C for 12 h. After the reaction, the washed and dried electrode was transferred to a tube furnace under a nitrogen atmosphere at 400 °C and annealed for 2 h. The resulting electrode was a RuSe2-CoTe / NC electrode.

[0033] application

[0034] 1. Activation treatment of electrocatalysts

[0035] (1) The electrochemical hydrogen evolution reaction (HER) uses a three-electrode system, with the working electrode having an area of ​​1 cm². 2 The RuSe2-CoTe / NC heterostructure catalyst has a graphite rod electrode as the counter electrode, a Hg / HgO electrode as the reference electrode, and a 1 mol L⁻¹ electrolyte. -1 KOH;

[0036] (2) Cyclic voltammetry (CV) activation: A Jiangsu Donghua DH7000 electrochemical workstation was used with a CV program. The HER test range was 0–0.8 V vs. RHE, and the scan rate was 100 mV s. -1 After 20 cycles, the electrode reaches a stable state.

[0037] 2. Linear sweep voltammetry (LSV) test

[0038] After activation, the program was switched to linear scan voltammetry, with the HER test range being 0 to -0.6V vs. RHE, and a scan rate of 5mV / s. -1 In an alkaline electrolyte, the electrocatalyst operates at -10 mA cm⁻¹. -2At that time, the overpotential of the electrocatalyst prepared in Example 1 was -25.4mV.

[0039] 3. Stability Test

[0040] After activation, a chronopotential method was used, with HER set to -10mA and time set to 108000s.

[0041] from Figure 1 The XRD pattern shows that the RuSe2-CoTe / NC heterostructure catalyst prepared in Example 1 has diffraction peaks for both RuSe2 and CoTe, as well as a Ni peak, indicating the successful preparation of the RuSe2-CoTe / NC heterostructure catalyst on a nickel foam substrate. Furthermore, from... Figure 2 SEM images show that the RuSe2-CoTe / NC heterostructure has a good nanosheet structure, and there are small spherical nanoparticles on the nanosheets. Figure 3 The EDS-Mapping spectrum showed seven elements: C, N, Ni, Co, Te, Ru, and Se, confirming the successful preparation of RuSe2-CoTe / NC.

[0042] Example 2

[0043] Compared with Example 1, the difference is that the concentration of sodium tellurite aqueous solution was changed to 0.5M in the preparation of CoTe / NF in step 3 of the preparation process.

[0044] The application method is the same as in Example 1, and the performance of HER is at -10mA cm -2 It exhibits an overpotential of -50.6mV at a given current density.

[0045] Example 3

[0046] Compared with Example 1, the difference is that the annealing temperature in step 4 of the preparation process of RuSe2-CoTe / NC is changed to 300℃.

[0047] The application method is the same as in Example 1, and the performance of HER is at -10mA cm -2 It exhibits an overpotential of -45.8mV at a given current density.

[0048] Example 4

[0049] Compared with Example 1, the difference is that the annealing temperature in step 4 of the preparation process of RuSe2-CoTe / NC is changed to 500℃.

[0050] The application method is the same as in Example 1, and the performance of HER is at -10mA cm -2 It exhibits an overpotential of -53.6mV at a given current density.

[0051] Example 5

[0052] Compared with Example 1, the difference is that the hydrothermal temperature in the third step of the preparation of CoTe / NF was changed to 120°C.

[0053] The application method is the same as in Example 1, and the performance of HER is at -10mA cm -2 It exhibits an overpotential of -86.4mV at a given current density.

[0054] Example 6

[0055] Compared with Example 1, the difference is that the hydrothermal temperature in step 4 of the preparation process of RuSe2-CoTe / NC was changed to 100°C.

[0056] The application method is the same as in Example 1, and the performance of HER is at -10mA cm -2 It exhibits an overpotential of -113.6mV at a given current density.

[0057] Comparative Example 1

[0058] Compared with the preparation of CoTe / NF alone in Example 1, the prepared CoTe / NF (same as in Example 1) was directly annealed at 400°C for 2 hours in a tube furnace under nitrogen atmosphere, and the resulting catalyst was a CoTe / NC electrode.

[0059] The application method is the same as in Example 1. The HER performance of CoTe / NF is at -10 mA / cm. -2 It exhibits an overpotential of -115mV at a given current density.

[0060] Comparative Example 2

[0061] 0.0098 g of selenium powder and 0.0129 g of ruthenium chloride were dissolved in the solution after vigorous stirring for 120 min. Then, 1 mL of hydrazine hydrate was added to the reaction solution, and the mixture was transferred to a 50 mL Teflon-lined autoclave. A 1.0 cm × 1.0 cm NF electrode was added to the autoclave, and the mixture was kept at 120 °C for 12 h. After the reaction, the washed and dried electrode was transferred to a tube furnace at 400 °C and calcined for 2 h to obtain a RuSe2 / NF electrode.

[0062] The application method is the same as in Example 1, and the performance of HER is at -10mA cm -2 It exhibits an overpotential of -65mV at a given current density.

[0063] Comparative Example 3

[0064] The electrode in Comparative Document 3 is a single NF electrode. The application method is the same as in Example 1, and the performance of the NF electrode HER is -10 mA / cm².-2 It exhibits an overpotential of -224mV at a given current density.

[0065] Comparative Example 4

[0066] 5 mg of commercially available Pt / C was dispersed in 375 μL of ultrapure water, 125 μL of ethanol, and 20 μL of 5 wt% Nafion solution, and sonicated for 30 min to form a homogeneous catalyst ink. The catalyst ink was then loaded onto a 1 × 1 cm NF substrate and allowed to air dry at room temperature.

[0067] The application method is the same as in Example 1, and the performance of HER is at -10mA cm -2 It exhibits an overpotential of -33.8 mV at a given current density. This demonstrates that Example 1 exhibits superior HER performance compared to commercially available Pt / C electrodes.

[0068] Comparative Example 5

[0069] Weigh 0.1725 g of cobalt nitrate hexahydrate solid and dissolve it in 20 mL of deionized water. Stir thoroughly for 10 min until the solid is completely dissolved. Then add 0.1316 g of sodium tellurite solid and stir thoroughly for 30 min until the solid is completely dissolved to prepare solution A. Next, weigh 0.501 g of ascorbic acid solid and dissolve it in 10 mL of deionized water. Add 10 mL of ethanolamine solution and stir thoroughly for 30 min until the mixture is homogeneous to prepare solution B. Mix solution B and solution A and stir for 30 min. Place the mixture in a hydrothermal reactor and add NF (1.0 cm × 1.0 cm). React at 220 °C for 24 h to obtain a catalyst of CoTe / NF.

[0070] The application method is the same as in Example 1, and the performance of HER is at -10mA cm -2 It exhibits an overpotential of -211mV at a given current density.

[0071] In Comparative Example 5, a CoTe / NF catalyst was directly synthesized via a hydrothermal method at -10 mA cm⁻¹. -2 It exhibits an overpotential of -211 mV at a given current density. Its performance is lower than that of CoTe / NC (-10 mA cm⁻¹). -2 The presence of an overpotential of -115 mV at a given current density confirms that the MOF material derivation preparation method of this invention promotes the performance of the catalyst.

Claims

1. A method for preparing a RuSe2-CoTe / NC heterostructure electrocatalyst, characterized in that, The preparation method comprises the following specific steps: (1) Cobalt chloride hexahydrate was added to N,N-dimethylformamide, and then 2-aminoterephthalic acid was mixed in the solution. NF was added and placed in a high-pressure reactor for hydrothermal reaction. The reacted material was washed and dried, and placed in an aqueous sodium tellurite solution for anion exchange. Then it was washed and dried to obtain CoTe / NF electrode. The sodium tellurite aqueous solution concentration was 0.5 M to 1.5 M, and the anion exchange time was 12 h to 36 h. (2) Selenium powder and ruthenium chloride were dissolved in deionized water, and then hydrazine hydrate was added to the reaction solution. The solution was then transferred to a high-pressure reactor, and a CoTe / NF electrode was added to it for hydrothermal reaction. After the reaction, the washed and dried electrode was transferred to a tube furnace under a nitrogen atmosphere for annealing. The resulting electrode was a RuSe2−CoTe / NC electrode.

2. The method for preparing the RuSe2-CoTe / NC heterostructure electrocatalyst according to claim 1, characterized in that, The mass ratio of 2-aminoterephthalic acid and cobalt chloride hexahydrate in step (1) is 1:1~1.

5.

3. The method for preparing the RuSe2-CoTe / NC heterostructure electrocatalyst according to claim 1, characterized in that, The hydrothermal reaction temperature in step (1) is 130 °C and the reaction time is 72 h.

4. The method for preparing the RuSe2-CoTe / NC heterostructure electrocatalyst according to claim 1, characterized in that, The molar ratio of ruthenium chloride and selenium powder in step (2) is 1:

2.

5. The method for preparing the RuSe2-CoTe / NC heterostructure electrocatalyst according to claim 1, characterized in that, The ratio of CoTe / NF electrode to selenium powder in step (2) is 1 cm⁻¹. 2 : 5~20 mg.

6. The method for preparing the RuSe2-CoTe / NC heterostructure electrocatalyst according to claim 2, characterized in that, The hydrothermal temperature in step (2) is 120 °C and the reaction time is 12 h.

7. The method for preparing the RuSe2-CoTe / NC heterostructure electrocatalyst according to claim 1, characterized in that, The annealing temperature in step (2) is 300 ℃~500 ℃, and the heating rate is 5 ℃ min. -1 The annealing time is 2 hours.

8. The application of a RuSe2-CoTe / NC heterostructure electrocatalyst prepared by the method according to any one of claims 1-7, characterized in that, The RuSe2-CoTe / NC heterostructure electrocatalyst is used for electrocatalytic hydrogen evolution in a three-electrode system under alkaline conditions.

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