Ni-MOF-coated MoS2 / NF material and preparation method and application thereof
Ni-MOF@MoS2/NF material prepared by two-step hydrothermal method solves the problems of high cost of precious metal catalysts and low conductivity of MoS2, and achieves efficient and stable electrocatalytic water hydrogen production, which is suitable for industrial applications.
Patent Information
- Application Number
- CN202411243130.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-05
- Publication Date
- 2024-12-10
AI Technical Summary
In the prior art, the rarity and high cost of precious metal-based catalysts limit the widespread application in the field of water cracking, and the low conductivity and limited active sites of MoS2 are not suitable for the field of overall water cracking.
Ni-MOF@MoS2/NF material was prepared by a two-step hydrothermal method, and Ni-MOF was used as a template to load MoS2 in situ on its surface to form an efficient and stable electrocatalyst to enhance the conductivity and active sites of the material.
It realizes efficient and stable electrocatalytic water hydrogen production, reduces costs, and the synergistic effect of the material's electrical conductivity and active sites improves the hydrogen evolution performance, which is suitable for industrial applications.
Smart Images
Figure CN119101947A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of hydrogen energy production, and specifically relates to a Ni-MOF@MoS2 / NF material and a preparation method and application thereof. Background Art
[0002] Energy depletion and severe environmental pollution are two imminent worldwide problems, which have prompted the focus of scientific research to shift to new energy sources such as water splitters, solar power generation systems, and fuel cells. Water splitters are a reliable way to provide clean fuel hydrogen, and can be considered as a promising energy carrier due to its renewable and environmentally friendly properties in the post-fossil era. Hydrogen energy is one of the new energy sources that has attracted much attention, and electrocatalytic water decomposition to produce hydrogen shows broad application prospects in clean energy production. Studies have shown that platinum-based (Pt) catalysts have a significant effect on reducing the HER overpotential, but the rarity and high cost of precious metal-based catalysts limit their widespread application. Based on this situation, finding an efficient and stable non-precious metal catalyst has become a research hotspot in the field of catalytic water splitting.
[0003] Metal-organic frameworks (MOFs) are a class of highly crystalline porous materials composed of organic ligands and metal ions or clusters, which have been widely used in various applications such as supercapacitors, gas adsorption or separation, catalysis, etc. The inherent properties of MOFs include large surface area, tunable pore structure, electronic adaptability, and diverse topology. However, most MOFs have poor electrical conductivity, which hinders the electron transfer and limits their application in electrochemistry. Fortunately, the uniform distribution of metal nodes and heteroatoms in highly ordered porous frameworks makes MOFs promising templates and / or precursors for the fabrication of functional heteroatom-doped carbon materials and metal-based compounds with superior electrical conductivity for various applications such as supercapacitors, lithium-ion batteries, and fuel cells.
[0004] Transition metal sulfides (TMSs) have attracted extensive research attention as bifunctional electrocatalysts for overall water splitting due to their abundant active sites, inherent advantages of high stability, and tunable electronic properties. Among various TMSs, researchers have focused on MoS2 due to its low hydrogen adsorption free energy (ΔGH < 0.6 eV) and unique 2D layered structure. However, the low conductivity and limited active sites of MoS2 make it unsuitable for the overall water splitting field. Therefore, researchers have explored various strategies to make up for the defects of MoS2, such as composite engineering, interface control, etc.
[0005] In view of this, how to use MOF materials and MoS2 to develop an efficient and stable catalyst is an important issue that needs to be urgently solved in the field of water splitting. Summary of the invention
[0006] The purpose of the present invention is to provide a Ni-MOF@MoS2 / NF material and a preparation method and application thereof. The present invention prepares a Ni-MOF@MoS2 / NF material for efficient and stable electrocatalytic water hydrogen production by a two-step hydrothermal method.
[0007] To achieve the above object, the technical solution of the present invention is as follows:
[0008] The first aspect of the present invention is a method for preparing a Ni-MOF@MoS2 / NF material, comprising the following steps:
[0009] Step 1: Mix and dissolve the nickel source and the organic ligand in N,N-dimethylformamide, and then add anhydrous ethanol and deionized water to obtain a mixed solution A; dissolve the molybdenum source and the sulfur source in deionized water to obtain a mixed solution B;
[0010] Step 2: placing nickel foam in mixed solution A for hydrothermal reaction, taking it out after the reaction is completed, washing and drying it to obtain a Ni-MOF / NF precursor;
[0011] Step 3: Place the Ni-MOF / NF precursor in mixed solution B for hydrothermal reaction. After the reaction is completed, take it out, wash and dry it to obtain Ni-MOF@MoS2 / NF material.
[0012] Furthermore, in step 1, the nickel source is nickel chloride hexahydrate, the organic ligand is trimesic acid, the molybdenum source is anhydrous sodium molybdate, and the sulfur source is thioacetamide.
[0013] Furthermore, in step 1, the molar ratio of nickel chloride hexahydrate to trimesic acid is 1:1.
[0014] Furthermore, in step 1, the molar ratio of anhydrous sodium molybdate to thioacetamide is 1:2.
[0015] Furthermore, the nickel foam in step 2 is pretreated before use, and the pretreatment method is: immersing the nickel foam in hydrochloric acid solution, acetone solvent and deionized water in sequence for ultrasonic washing, taking it out and drying it.
[0016] Furthermore, the temperature of the hydrothermal reaction in step 2 is 180° C. and the time is 12 h.
[0017] Furthermore, the temperature of the hydrothermal reaction in step 3 is 160° C. and the time is 12 h.
[0018] The second aspect of the present invention is the Ni-MOF@MoS2 / NF material prepared by the preparation method described in the first aspect.
[0019] The third aspect of the present invention is a working electrode, comprising the Ni-MOF@MoS2 / NF material described in the second aspect.
[0020] The fourth aspect of the present invention is the use of the Ni-MOF@MoS2 / NF material described in the second aspect or the working electrode described in the third aspect in alkaline water electrolysis to produce hydrogen.
[0021] Compared with the prior art, the present invention has the following beneficial effects:
[0022] The present invention selects Ni-MOF / NF as a substrate, loads MoS2 in situ on its surface through a hydrothermal reaction, and finally successfully prepares Ni-MOF@MoS2 / NF material. The method has a simple preparation process and low cost, and the obtained material has good electrical conductivity and abundant active sites. The synergistic effect between Ni-MOF and MoS2 in the material makes the material have better hydrogen evolution performance, and the nickel foam increases the area of contact between the material and water. It has high catalytic activity as a HER catalyst, can be used for alkaline water electrolysis to produce hydrogen, and is suitable for industrial application. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 SEM images of the Ni-MOF@MoS2 / NF material prepared in Example 1 and the Ni-MOF / NF material prepared in Comparative Example 2;
[0024] Figure 2 XPS graphs of the Ni-MOF@MoS2 / NF material prepared in Example 1 and the Ni-MOF / NF material prepared in Comparative Example 2;
[0025] Figure 3 Polarization curves of the Ni-MOF@MoS2 / NF material prepared in Example 1, the NF material prepared in Comparative Example 1, the Ni-MOF / NF material prepared in Comparative Example 2, and the MoS2 / NF material prepared in Comparative Example 3;
[0026] Figure 4 This is the hydrogen evolution stability diagram of the Ni-MOF@MoS2 / NF material prepared in Example 1. DETAILED DESCRIPTION
[0027] In order to facilitate the understanding of the present invention, the present invention will be described more fully below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.
[0028] Example 1
[0029] Preparation of Ni-MOF@MoS2 / NF materials
[0030] (1) Pretreatment of nickel foam (NF): immersing the nickel foam in a 6 mol / L hydrochloric acid solution, an acetone solvent and deionized water for ultrasonic washing in sequence, and drying the rinsed nickel foam in an oven to obtain pretreated nickel foam;
[0031] (2) Preparation of raw materials: 0.5 mmol of nickel chloride hexahydrate and 0.5 mmol of trimesic acid were dissolved in 10.5 mL of N,N-dimethylformamide, and then 0.75 mL of anhydrous ethanol and 0.75 mL of deionized water were added to obtain a mixed solution A; 1.25 mmol of anhydrous sodium molybdate and 2.5 mmol of thioacetamide were dissolved in 7.5 mL of deionized water to obtain a mixed solution B;
[0032] (3) Primary hydrothermal: The mixed solution A was transferred to a high-temperature polytetrafluoroethylene reactor and the pretreated nickel foam was placed in the reactor. The mixture was reacted at 180°C for 12 h. After the reaction, the mixture was taken out and rinsed with DMF, anhydrous ethanol and deionized water several times, and then dried in an oven to obtain a Ni-MOF / NF precursor.
[0033] (4) Secondary hydrothermal treatment: The mixed solution B was transferred to a high-temperature polytetrafluoroethylene reactor and the precursor Ni-MOF / NF was placed in it. The mixture was reacted at 160 °C for 6 h. After the reaction was completed, the mixture was taken out, washed with deionized water several times, and dried in an oven to obtain the Ni-MOF@MoS2 / NF material.
[0034] Comparative Example 1
[0035] Preparation of NF materials
[0036] The nickel foam is sequentially immersed in a 6 mol / L hydrochloric acid solution, an acetone solvent and deionized water for ultrasonic washing, and the washed nickel foam is placed in an oven for drying to obtain a NF material.
[0037] Comparative Example 2
[0038] Preparation of Ni-MOF / NF
[0039] (1) Pretreatment of nickel foam: immersing the nickel foam in 6 mol / L hydrochloric acid solution, acetone solvent and deionized water for ultrasonic washing in sequence, and drying the rinsed nickel foam in an oven to obtain pretreated nickel foam;
[0040] (2) Raw material preparation: 0.5 mmol nickel chloride hexahydrate and 0.5 mmol trimesic acid were dissolved in 10.5 mL N,N-dimethylformamide, and then 0.75 mL anhydrous ethanol and 0.75 mL deionized water were added to obtain a mixed solution;
[0041] (3) Hydrothermal reaction: The mixed solution was transferred to a high-temperature polytetrafluoroethylene reactor and the pretreated nickel foam was placed in the reactor for reaction at 180°C for 12 h. After the reaction was completed, the mixed solution was taken out and rinsed several times with DMF, anhydrous ethanol and deionized water, and then dried in an oven to obtain the Ni-MOF / NF material.
[0042] Comparative Example 3
[0043] Preparation of MoS2 / NF materials
[0044] (1) Pretreatment of nickel foam: immersing the nickel foam in 6 mol / L hydrochloric acid solution, acetone solvent and deionized water for ultrasonic washing in sequence, and drying the rinsed nickel foam in an oven to obtain pretreated nickel foam;
[0045] (2) Raw material preparation: 1.25 mmol of anhydrous sodium molybdate and 2.5 mmol of thioacetamide were dissolved in 7.5 mL of deionized water to obtain a mixed solution;
[0046] (3) Hydrothermal reaction: The mixed solution was transferred to a high-temperature polytetrafluoroethylene reactor and the nickel foam after precursor pretreatment was placed therein. The mixture was reacted at 160°C for 6 h. After the reaction was completed, the mixture was taken out, washed with deionized water several times, and dried in an oven to obtain MoS2 / NF material.
[0047] The SEM images of the Ni-MOF@MoS2 / NF material prepared in Example 1 and the Ni-MOF / NF material prepared in Comparative Example 2 are as follows: Figure 1 As shown in the figure, it can be seen that the Ni-MOF / NF material is aggregated from flakes into a flower shape. The Ni-MOF@MoS2 / NF material is a nano-flower with more wrinkles. The latter increases the specific surface area, increases the contact area between the material and water, and improves the nanostructure, which improves the hydrogen evolution performance and enhances the stability.
[0048] The XPS images of the Ni-MOF@MoS2 / NF material prepared in Example 1 and the Ni-MOF / NF material prepared in Comparative Example 2 are shown in FIG. Figure 2 As shown in the figure, the main components of Ni-MOF / NF material are Ni, C and O. After MoS2 is deposited on Ni-MOF, the spectrum of Ni-MOF@MoS2 / NF material shows the presence of Mo and S elements. In addition, the XPS spectrum of Ni-MOF@MoS2 / NF material shows binding energy peaks at 856.47, 231.86 and 161.40 eV, confirming that the valences of Ni, Mo and S are +2, +4 and -2, respectively.
[0049] Hydrogen evolution electrochemical test: HER test was performed using an electrochemical workstation (CHI660E, CHInstruments). The three-electrode system used in the test process included: the working electrode was the Ni-MOF@MoS2 / NF material prepared in Example 1, the NF material prepared in Comparative Example 1, the Ni-MOF / NF material prepared in Comparative Example 2, or the MoS2 / NF material prepared in Comparative Example 3, the counter electrode was graphite, the reference electrode was Ag / AgCl, and the electrolyte was 1M KOH. The test results are shown in Figure 2. Figure 3 As shown in the figure, Ni-MOF@MoS2 / NF material, NF material, Ni-MOF / NF material, and MoS2 / NF material are 2 The overpotentials are 89mV, 169mV, 115mV, and 130mV, respectively. By comparison, it can be seen that the overpotential of Ni-MOF@MoS2 / NF material at this current density is the lowest, proving that the material further improves the electrochemical hydrogen evolution performance based on the precursor.
[0050] Stability test: The test method is the same as the hydrogen evolution electrochemical test. Figure 4 As shown, the Ni-MOF@MoS2 / NF material prepared in Example 1 has good stability.
[0051] The above description is only for better explaining the embodiments of the present invention, and is not intended to limit the present invention. Any modification or equivalent substitution that does not depart from the spirit and scope of the present invention shall fall within the scope of the present invention.
Claims
1. A method for preparing Ni-MOF@MoS2 / NF material, characterized in that: The following steps are involved: Step 1: Mix and dissolve the nickel source and the organic ligand in N,N-dimethylformamide, and then add anhydrous ethanol and deionized water to obtain a mixed solution A; dissolve the molybdenum source and the sulfur source in deionized water to obtain a mixed solution B; Step 2: placing nickel foam in mixed solution A for hydrothermal reaction, taking it out after the reaction is completed, washing and drying it to obtain a Ni-MOF / NF precursor; Step 3: Place the Ni-MOF / NF precursor in mixed solution B for hydrothermal reaction. After the reaction is completed, take it out, wash and dry it to obtain Ni-MOF@MoS2 / NF material.
2. The method for preparing the Ni-MOF@MoS2 / NF material according to claim 1, characterized in that: In step 1, the nickel source is nickel chloride hexahydrate, the organic ligand is trimesic acid, the molybdenum source is anhydrous sodium molybdate, and the sulfur source is thioacetamide.
3. The method for preparing the Ni-MOF@MoS2 / NF material according to claim 2, characterized in that: In the step 1, the molar ratio of nickel chloride hexahydrate to trimesic acid is 1:
1.
4. The method for preparing the Ni-MOF@MoS2 / NF material according to claim 2, characterized in that: The molar ratio of anhydrous sodium molybdate to thioacetamide in step 1 is 1:
2.
5. The method for preparing the Ni-MOF@MoS2 / NF material according to claim 1, characterized in that: The nickel foam in step 2 needs to be pretreated before use, and the pretreatment method is: immersing the nickel foam in hydrochloric acid solution, acetone solvent and deionized water for ultrasonic washing in sequence, taking it out and drying it.
6. The method for preparing the Ni-MOF@MoS2 / NF material according to claim 1, characterized in that: The temperature of the hydrothermal reaction in step 2 is 180° C. and the time is 12 h.
7. The method for preparing the Ni-MOF@MoS2 / NF material according to claim 1, characterized in that: The temperature of the hydrothermal reaction in step 3 is 160° C. and the time is 12 h.
8. Ni-MOF@MoS2 / NF material obtained by the preparation method according to any one of claims 1 to 7.
9. A working electrode, characterized in that Including the Ni-MOF@MoS2 / NF material as described in claim 8.
10. Use of the Ni-MOF@MoS2 / NF material according to claim 8 or the working electrode according to claim 9 in hydrogen production by alkaline water electrolysis.