Preparation method of composite electrode for electro-catalytic hydrogen evolution reaction
By constructing a composite electrode with a niobium carbide-molybdenum sulfide heterostructure, the stability and activity issues of MXene materials in the electrocatalytic hydrogen evolution reaction were solved, and high-efficiency electrocatalytic hydrogen evolution performance was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-13
- Publication Date
- 2026-04-03
AI Technical Summary
Existing MXene materials suffer from problems such as low hydrogen adsorption energy, limited active sites, easy interlayer stacking, and insufficient stability in oxygen-rich environments during electrocatalytic hydrogen evolution reactions, which limits their practical applications.
An interface engineering strategy was adopted to construct a niobium carbide-molybdenum sulfide heterostructure. Niobium carbide nanosheets were loaded onto the surface of nickel foam through layer-by-layer self-assembly in polyethyleneimine solution, and molybdenum sulfide was grown on it by solvothermal method to form a composite electrode with synergistic effect.
It significantly improved the electrocatalytic hydrogen evolution activity, reduced the hydrogen evolution overpotential, enhanced electron transport capability, and improved the stability and catalytic performance of the material.
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Abstract
Description
Technical Field
[0001] This invention relates to the preparation of multi-component multifunctional materials, and its application belongs to the field of electrocatalysis and energy conversion materials and devices. Background Technology
[0002] Hydrogen energy, as a clean, efficient, safe, and sustainable energy source, will occupy a crucial position in the future global energy system. Against the backdrop of actively promoting energy transition and addressing climate change globally, developing efficient and clean hydrogen production technologies has become a core task facing both the scientific and industrial communities. Among these technologies, water electrolysis for hydrogen production is considered a vital pathway for large-scale hydrogen production due to its green and environmentally friendly process characteristics, with the hydrogen evolution reaction (HER) occurring at the cathode being a key step in hydrogen generation. However, current commercial electrocatalysts heavily rely on scarce and expensive precious metals, resulting in high hydrogen production costs and severely restricting the large-scale application of water electrolysis for hydrogen production. Therefore, the ongoing global exploration of efficient, stable, and low-cost non-precious metal electrocatalysts has become a key research direction for promoting the development of the green hydrogen industry.
[0003] MXenes are a class of two-dimensional transition metal carbides / nitrides, considered potential candidates for electrocatalytic hydrogen evolution reaction (HER) due to their high metallic conductivity, tunable surface chemistry, and excellent mechanical and thermal stability. However, in HER applications, MXene materials generally suffer from low hydrogen adsorption energy, limited active site types, susceptibility to interlayer stacking, and insufficient stability in oxygen-rich environments, severely limiting their practical application. To address these challenges, this invention proposes an interface engineering strategy to construct a niobium carbide-molybdenum sulfide heterostructure to effectively optimize the electrocatalytic hydrogen evolution performance of MXene-based materials. Summary of the Invention
[0004] In view of this, the technical problem to be solved by the present invention is to provide an electrocatalytic hydrogen evolution reaction (HER) composite electrode and its preparation method, wherein the composite material has excellent electrocatalytic hydrogen evolution performance.
[0005] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing a niobium carbide-molybdenum sulfide composite electrode for electrocatalytic hydrogen evolution reaction (HER) is as follows:
[0006] 1) Pretreatment of nickel foam (thickness range 1 mm ~ 2 mm, porosity ≥ 95%, pore size 0.1 mm): The nickel foam is ultrasonicated for 15 min in sequence with acetone and hydrochloric acid, rinsed repeatedly with deionized water, ultrasonicated with ethanol for 15 min, and then dried for later use.
[0007] 2) Preparation method of conductive substrate: Washed nickel foam is repeatedly immersed in polyethyleneimine solution and niobium carbide suspension for 2-7 min, rinsed and dried, and after 5-15 times, nickel foam modified with niobium carbide with different number of layers is obtained.
[0008] 3) Preparation method of niobium carbide-molybdenum sulfide: A conductive substrate is placed in a reaction vessel, and a mixed solution of thiourea and ammonium molybdate in a ratio of 1:4-8 is added. The reaction temperature is 120-160 °C, and the reaction time is 10-12 h. After cooling to room temperature, the nickel foam loaded with niobium carbide-molybdenum sulfide is removed, rinsed with deionized water and ethanol, and dried to obtain a niobium carbide-molybdenum sulfide composite electrode for electrocatalytic HER.
[0009] Compared with traditional technologies, this application has at least the following beneficial effects:
[0010] The electrocatalytic hydrogen evolution catalyst of this application uses a polyethyleneimine solution as a linker to uniformly load niobium carbide nanosheets onto the surface of nickel foam through a layer-by-layer self-assembly process, constructing a conductive substrate. This niobium carbide-modified nickel foam substrate exhibits advantages such as uniform loading distribution, structural stability, and resistance to detachment. Based on this, molybdenum sulfide is uniformly grown on the surface of the niobium carbide nanosheets using a solvothermal method. Benefiting from the excellent layered structure and high conductivity of niobium carbide, the directional growth of molybdenum sulfide on its surface not only fully exposes its catalytic active sites but also significantly enhances the overall electron transport capacity of the composite material. A synergistic effect is formed between niobium carbide and molybdenum sulfide, effectively enhancing the electrocatalytic hydrogen evolution activity, reducing the hydrogen evolution overpotential, and thus reducing energy consumption in the hydrogen production process. Attached Figure Description
[0011] Figure 1 This is a SEM image of the few-layer niobium carbide synthesized in Example 2 of the present invention.
[0012] Figure 2 This is a SEM image of the niobium carbide-molybdenum sulfide composite electrode prepared in Example 5 of the present invention.
[0013] Figure 3 The graphs show the HER linear voltammetric scans of the composite electrodes and pure-phase molybdenum sulfide prepared in Examples 4 to 6 of this invention.
[0014] Figure 4 The composite electrode prepared in Example 5 of this invention is at 10 mA cm⁻¹ -2 Stability curve (it) under constant current. Detailed Implementation
[0015] The HER performance of the composite electrode was tested using linear voltammetry (LSV). The specific method was as follows: the prepared composite material was used as the working electrode, a carbon rod as the counter electrode, a saturated Hg / HgO electrode as the reference electrode, and a 1M KOH aqueous solution as the electrolyte. The scan rate was 5–10 mV / s. Nitrogen gas was introduced during the HER test to allow it to naturally saturate in the 1M KOH aqueous solution, and stirring was performed at 200 rpm throughout the test. The saturated Hg / HgO electrode was calibrated using a reversible hydrogen electrode; all potentials mentioned below are relative to the reversible hydrogen electrode. The potentials in the LSV test were 90% (IR) compensated, corresponding to… Figure 3 . Figure 4 For stability testing, a niobium carbide-molybdenum sulfide composite was used as the working electrode, and electrolysis was performed in 1M KOH electrolyte.
[0016] Example 1
[0017] Nickel foam pretreatment: Select nickel foam with a thickness of 1 mm, a porosity of 97.2%, and a pore size of 0.1 mm, and cut it into 4×2 cm pieces. 2 The samples were sized and then subjected to ultrasonic treatment with acetone and hydrochloric acid for 15 min each, rinsed repeatedly with deionized water, and then ultrasonicated in ethanol for 15 min. They were then dried and ready for use.
[0018] Example 2
[0019] Preparation of few-layer niobium carbide suspension: 2.5 g of lithium fluoride and 40 mL of concentrated hydrochloric acid were added to a 100 mL reactor and stirred for 30 min. 2 g of Nb₂AlC was slowly added, and a solvothermal reaction was initiated at 180 ℃ for 24 h. After the reaction was complete and cooled to room temperature, the product in the reactor was washed repeatedly by centrifugation (4000 rpm) with deionized water until pH ≥ 6. 40 mL of 25% tetramethylammonium hydroxide aqueous solution was added, and the mixture was sonicated for 4 h. Centrifugation was repeated (10000 rpm) to remove the intercalating agent. 15 mL of deionized water was added, and the mixture was shaken well and centrifuged again to obtain the few-layer niobium carbide suspension.
[0020] Example 3
[0021] Preparation of conductive substrate: The obtained few-layer suspension was diluted to 2 mg / mL. The treated nickel foam was first immersed in 0.05 mmol / L polyethyleneimine solution for 5 min, then rinsed and dried. It was then immersed in 2 mg / mL few-layer suspension for 5 min, then dried. This process was repeated 5 times.
[0022] Example 4
[0023] Preparation of niobium carbide-molybdenum sulfide: 0.38 g of ammonium molybdate and 0.82 g of thiourea were added to 40 mL of deionized water and stirred evenly. The mixture was then poured into a 100 mL reaction vessel. The conductive substrate prepared in Example 3 was placed into the reaction vessel. The reaction temperature was 150 °C and the reaction time was 12 h. After the reaction was completed, the temperature was lowered to room temperature. The product was taken out and washed with deionized water and ethanol. It was then dried under vacuum at 60 °C for 12 h to obtain the niobium carbide-molybdenum sulfide composite electrode, denoted as niobium carbide-molybdenum sulfide-1.
[0024] Based on the materials provided by this invention, the applicant has systematically adjusted the number of soaking times while maintaining the same raw material ratio during the preparation of Nb2C-NF. Specific embodiments are as follows:
[0025] Example 5
[0026] Compared with Example 4, the difference is that the immersion was repeated 10 times before the next solvothermal reaction was carried out to obtain the niobium carbide-molybdenum sulfide composite electrode, denoted as niobium carbide-molybdenum sulfide-2.
[0027] Example 6
[0028] Compared with Example 4, the difference is that the niobium carbide-molybdenum sulfide composite electrode was obtained by repeated soaking 15 times, and it is denoted as niobium carbide-molybdenum sulfide-3.
[0029] Related data and image analysis:
[0030] Figure 1 The image is a SEM image of few-layer niobium carbide, clearly showing a lamellar structure, indicating that the Nb2AlC layers have been peeled apart to form a few-layer structure.
[0031] Figure 2 This is a SEM image of the niobium carbide-molybdenum sulfide composite electrode, where nano-flower-shaped molybdenum sulfide is clearly visible and uniformly distributed on the niobium carbide.
[0032] Figure 3 The composite electrodes obtained in Examples 4-6 were tested using linear voltammetry (LSV). It can be seen that the pure-phase molybdenum sulfide material exhibits a current density of 10 mA cm⁻¹ at an overpotential of 180 mV. -2 When the overpotential of the niobium carbide-molybdenum sulfide-1 material is 165 mV, the current density reaches 10 mA cm⁻¹. -2 When the overpotential of niobium carbide-molybdenum sulfide-2 is 133 mV, the current reaches 10 mA cm⁻¹. -2 When the overpotential of the niobium carbide-molybdenum sulfide material is 165 mV, the current density reaches 10 mA cm⁻¹. -2 Comparison with 10 mAcm -2Under the influence of the overpotential, niobium carbide-molybdenum sulfide-2 exhibits superior electrocatalytic performance.
[0033] Figure 4 This is the electrochemical cycling stability (it) curve of the niobium carbide-molybdenum sulfide-2 composite electrode. Figure 4 It can be seen that the niobium carbide-molybdenum sulfide-2 composite electrode material has good stability, and the current density does not decrease significantly within 48 hours under a constant voltage of 133 mV.
[0034] The embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Identical or similar content can be referred to interchangeably. The apparatus solutions disclosed in the embodiments are described briefly because they correspond to the aforementioned method implementation schemes; relevant content can be found in the method section.
[0035] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the specific embodiments described. For those skilled in the art, various improvements, adjustments, substitutions, or equivalent transformations to the embodiments without departing from the principles and spirit of the present invention should all fall within the protection scope of the present invention.
Claims
1. A method for preparing a niobium carbide-molybdenum sulfide composite electrode for electrocatalytic hydrogen evolution reaction (HER), characterized in that, The composite electrode uses niobium carbide to modify the surface of nickel foam, providing an environment for the growth of molybdenum sulfide, so that molybdenum sulfide is coated on the surface of niobium carbide to form a heterostructure.
2. A method for preparing a niobium carbide-molybdenum sulfide composite electrode for electrocatalytic hydrogen evolution reaction (HER), characterized in that... Its conductive substrate is niobium carbide-modified nickel foam.
3. The conductive substrate according to claim 2 is characterized in that... Using a few-layer niobium carbide suspension and a polyethyleneimine solution, few-layer niobium carbide nanosheets and positively charged amino molecular chains were uniformly loaded onto nickel foam layer by layer using an interlayer alternating loading method.
4. The preparation method according to claim 3 is characterized in that... The suspension concentration was 1-4 mg / mL. The nickel foam was alternately immersed in a polyethyleneimine solution with a concentration of 0.025-0.1 mmol / mL and a few-layer niobium carbide suspension for 2-7 min. The immersion was repeated 5-15 times to obtain conductive substrates with different numbers of layers.
5. A method for preparing a niobium carbide-molybdenum sulfide composite electrode for electrocatalytic hydrogen evolution reaction (HER) according to claim 1, characterized in that... The prepared conductive substrate was placed in a reaction vessel, and a mixed solution of thiourea and ammonium molybdate was added in a ratio of 1:4-8. The solvothermal reaction temperature was 120-160 ℃ and the reaction time was 10-12 h to obtain a niobium carbide-molybdenum sulfide composite electrode.
6. A method for preparing a niobium carbide-molybdenum sulfide composite electrode for electrocatalytic hydrogen evolution reaction (HER), characterized in that, It is prepared by the method described in any one of claims 1 to 5.