Preparation method and application of CNTs (at) Bi electro-catalytic material
By wrapping bismuth nanoparticles on carbon nanotubes, the problem of insufficient catalytic efficiency and selectivity in CO2 electrochemical reduction is solved, and the effect of efficient generation of formic acid is achieved. It is suitable for pharmaceutical and hydrogen storage applications.
Patent Information
- Application Number
- CN202411572673.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-06
- Publication Date
- 2024-12-24
AI Technical Summary
The prior art is difficult to efficiently catalyze the generation of high added value formic acid in CO2 electrochemical reduction, and the selectivity and stability of the catalyst are insufficient, which affects its application in pharmaceutical, leather and other industries.
Using the preparation method of CNTs@Bi electrocatalytic material, SPNTs are prepared by encapsulating bismuth nanoparticles on carbon nanotubes (CNTs), and calcining in a nitrogen environment to prepare CNTs@Bi as an electrocatalyst for carbon dioxide. Electrocatalytic reduction.
It has achieved efficient catalytic reduction of carbon dioxide to produce formic acid, with a Faraday efficiency of 64%, good selectivity and stable performance, and is suitable as a candidate material for liquid fuel and hydrogen storage materials.
Smart Images
Figure CN119177470A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of electrocatalytic materials, and in particular relates to a preparation method and application of a CNTs@Bi electrocatalytic material. Background Art
[0002] Using renewable green electricity such as solar energy, wind energy, and tidal energy to convert carbon dioxide into high-value-added chemicals or raw materials is considered an ideal way to alleviate the increasing carbon dioxide emissions and energy shortage crisis. Among various CO2 reduction strategies, electrochemical CO2 reduction reaction has attracted more and more attention due to its mild conditions and easy implementation. The products of CO2 electrochemical reduction include gaseous and liquid chemicals such as CO, CH4, formic acid, and alcohols, which can meet various application requirements. Due to the difficulty of CC coupling, C1 products are more expensive than C 2+ The product is easier to generate. Among C1 products, formic acid has the highest added value and is a raw material widely used in the pharmaceutical, leather, printing and dyeing industries. As a liquid fuel, formic acid is also an ideal hydrogen storage material due to its safety, convenient storage, and transportability. It is a promising candidate material for hydrogen fuel cell applications. In this context, it is imperative to master the design and preparation of electrocatalysts under CO2 electroreduction. Summary of the invention
[0003] The purpose of the present invention is to provide a method for preparing a CNTs@Bi electrocatalyst material with high catalytic efficiency, high selectivity and stable performance.
[0004] To achieve the above object, the technical solution adopted by the present invention is:
[0005] A method for preparing a CNTs@Bi electrocatalytic material comprises the following steps:
[0006] 1) Preparation of SPNTs: PNTs are immersed in concentrated sulfuric acid and stirred, diluted with a large amount of water, filtered, washed, and dried to obtain SPNTs;
[0007] 2) Preparation of CNTs@Bi: Bi salt and SPNTs obtained in step 2) are stirred in ethanol, washed by centrifugation and dried, and calcined in a nitrogen environment to obtain CNTs@Bi.
[0008] Furthermore, the above-mentioned preparation method, the preparation method of PNTs includes the following steps: adding 4g of divinylbenzene to 100g of n-heptane to form a mixed solution, then adding 100mg of boron trifluoride diethyl ether to the above-mentioned mixed solution, and after ultrasonic reaction for 10 to 20 minutes, a large amount of white fibers are produced, and then ethanol is added to terminate the reaction. The white fibers are filtered, washed, and dried in a vacuum oven at 60°C to obtain PNTs.
[0009] Furthermore, in the above preparation method, in step 1), the stirring condition is: stirring at 50° C. for 12 h.
[0010] Furthermore, in the above preparation method, in step 2), the bismuth salt is bismuth neodecanoate.
[0011] Furthermore, in the above preparation method, in step 2), the amount of the bismuth salt added is 0.5-1 g, the amount of SPNTs added is 50-100 mg, and the volume of ethanol is 10 mL.
[0012] Furthermore, in the above preparation method, in step 2), the stirring time is 10 to 12 hours.
[0013] Furthermore, in the above preparation method, in step 2), the drying condition is: drying at 80° C. for 10 to 12 hours.
[0014] Furthermore, in the above preparation method, in step 2), the calcination conditions are: calcination at 550°C to 850°C for 2h, and the heating rate is 5°C / min.
[0015] Application of the CNTs@Bi electrocatalytic material prepared by any of the preparation methods described above in the electrocatalytic reduction of carbon dioxide to synthesize formic acid.
[0016] Furthermore, the above-mentioned application method is as follows: using an H-type electrolytic cell and a three-electrode working system, 0.5M KHCO3 is used as the electrolyte, the electrolyte is injected into the cathode chamber and the anode chamber respectively, and carbon dioxide is introduced into the cathode chamber for 30 minutes to saturate it; carbon paper with CNTs@Bi electrocatalytic material added is used as the working electrode, platinum mesh is used as the counter electrode, and Ag / AgCl is used as the reference electrode to electrocatalyze carbon dioxide reduction to synthesize formic acid.
[0017] Furthermore, in the above application, the preparation method of the carbon paper with the CNTs@Bi electrocatalytic material added is as follows: 5 mg of CNTs@Bi electrocatalytic material is mixed with 750 μL of ethanol, 200 μL of deionized water, and 50 μL of Nafion for half an hour until a uniform ink is formed, and 100 μL of the ink is dropped on a 0.5×2 cm 2 The commercial carbon paper was dried to obtain the carbon paper with CNTs@Bi electrocatalytic material added.
[0018] The beneficial effects of the present invention are as follows: the present invention adopts a green and simple impregnation method to prepare SPNTs-wrapped bismuth nanoparticle catalyst. The CNTs@Bi electrocatalytic material provided by the present invention has high catalytic efficiency, good selectivity and stable performance in electrocatalytic carbon dioxide reduction. At a voltage of -0.97V vs.RHE, the Faraday efficiency of formic acid in 0.5M KHCO3 saturated with carbon dioxide reaches 64%. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 This is a transmission electron microscope image of CNTs@Bi electrocatalytic material.
[0020] Figure 2 is the X-ray diffraction pattern (XRD) of CNTs@Bi electrocatalytic material.
[0021] Figure 3 This is the linear sweep voltammogram of CNTs@Bi electrocatalytic material used for electrocatalytic carbon dioxide reduction to synthesize formic acid.
[0022] Figure 4 This is the Faraday efficiency diagram of CNTs@Bi electrocatalytic material used for electrocatalytic carbon dioxide reduction to generate products. DETAILED DESCRIPTION
[0023] In order to better understand the technical solution of the present invention, a specific embodiment is further described in detail, but the solution is not limited thereto.
[0024] Example 1 CNTs@Bi electrocatalytic material
[0025] (I) The preparation method is as follows:
[0026] 1) Preparation of PNTs:
[0027] 4 g of divinylbenzene was added to 100 g of n-heptane to form a mixed solution, and then 100 mg of boron trifluoride diethyl ether was added to the mixed solution. After ultrasonic reaction for 10 minutes, a large amount of white fibers were produced. Then, ethanol was added dropwise to terminate the reaction. The white fibers were filtered, washed, and dried in a vacuum oven at 60°C to obtain PNTs.
[0028] 2) Preparation of SPNTs:
[0029] 0.2 g of PNTs obtained in step 1) were immersed in 30 mL of 98% concentrated sulfuric acid, stirred at 50° C. for 12 h, diluted with a large amount of deionized water, and the sample was collected by filtration, washed with water and ethanol, and dried to obtain SPNTs.
[0030] 3) Preparation of CNTs@Bi:
[0031] 1 g of bismuth neodecanoate and 100 mg of SPNTs obtained in step 2) were added to 10 mL of ethanol, stirred at room temperature for 10 h, centrifuged and washed, dried at 80 °C for 12 h, and then calcined at 750 °C for 2 h (heating rate of 5 °C / min) under nitrogen atmosphere to obtain CNTs@Bi.
[0032] 4) Preparation of working electrode:
[0033] 5 mg of CNTs@Bi obtained in step 3) was mixed with 750 μL of ethanol, 200 μL of deionized water, and 50 μL of Nafion and ultrasonicated for half an hour until a uniform ink was formed. 100 μL of the ink was dropped on a 0.5×2 cm 2 The commercial carbon paper with CNTs@Bi electrocatalytic material added was dried and used as the working electrode.
[0034] (II) Testing
[0035] Figure 1 This is a transmission electron microscopy image of CNTs@Bi electrocatalytic material. Figure 1 It can be seen that the prepared electrocatalytic material presents an obvious carbon nanotube shape, and the bismuth nanoparticles are completely wrapped in the inner cavity of the nanotube, presenting a cowpea-like structure.
[0036] Figure 2 is the X-ray diffraction pattern (XRD) of CNTs@Bi electrocatalytic material, Figure 2 It can be seen that the crystal phase belonging to Bi metal particles is observed, indicating that metal Bi and carbon nanotubes are successfully composited.
[0037] Example 2 Application of CNTs@Bi electrocatalytic material in electrocatalytic carbon dioxide reduction to synthesize formic acid
[0038] The electrochemical properties of the catalyst were tested using a CHI760 electrochemical workstation, and an H-type electrolytic cell and a three-electrode working system were used for electrochemical performance testing.
[0039] The method is as follows: an H-type electrolytic cell and a three-electrode working system are used, 0.5M KHCO3 is used as the electrolyte, 20mL of electrolyte is injected into the cathode chamber and the anode chamber respectively, and carbon dioxide is introduced into the cathode chamber for 30min to saturate it; the carbon paper with CNTs@Bi electrocatalytic material added is used as the working electrode, the platinum mesh is used as the counter electrode, and Ag / AgCl is used as the reference electrode to analyze the electrochemical performance. During the test, the stirring rate of the cathode electrolyte is 500rpm, and the scanning speed of the linear scan is 0.05Vs -1 The voltage used is based on the standard hydrogen electrode.
[0040] Figure 3 This is the linear sweep voltammetric curve of CNTs@Bi electrocatalytic material used for electrocatalytic reduction of carbon dioxide to synthesize formic acid. Figure 3 As shown in the figure, the linear sweep voltammetry curve of CNTs@Bi electrocatalyst material in the electrolyte under Ar / CO2 environment shows that after adding CO2, at the same voltage, the current density of CNTs@Bi electrocatalyst material is larger, indicating that CNTs@Bi-based electrocatalyst material has a positive response to the reduction of carbon dioxide.
[0041] Figure 4 This is the Faraday efficiency diagram of CNTs@Bi electrocatalytic material used for electrocatalytic reduction of carbon dioxide to generate products. Figure 4 As shown in the figure, among the products obtained by electro-reduction of carbon dioxide by CNTs@Bi electrocatalytic material at different voltages, formic acid accounts for the highest proportion, and the Faraday efficiency reaches the maximum value of 64% at -0.97V vs. RHE voltage. It can be seen that CNTs@Bi electrocatalytic material has high product selectivity and good catalytic efficiency in the electro-reduction of carbon dioxide.
Claims
1. A method for preparing a CNTs@Bi electrocatalytic material, characterized in that: The steps include: 1) Preparation of SPNTs: PNTs are immersed in concentrated sulfuric acid and stirred, diluted with a large amount of water, filtered, washed, and dried to obtain SPNTs; 2) Preparation of CNTs@Bi: Bi salt and SPNTs obtained in step 2) are stirred in ethanol, washed by centrifugation and dried, and calcined in a nitrogen environment to obtain CNTs@Bi.
2. The preparation method according to claim 1, characterized in that: The preparation method of PNTs comprises the following steps: adding 4g of divinylbenzene to 100g of n-heptane to form a mixed solution, then adding 100mg of boron trifluoride diethyl ether to the mixed solution, and subjecting the mixed solution to ultrasonic reaction for 10 to 20 minutes to generate a large amount of white fibers, then dropping ethanol to terminate the reaction, and filtering and washing the white fibers, and drying them in a vacuum oven at 60°C to obtain PNTs.
3. The preparation method according to claim 1, characterized in that: In step 1), the stirring condition is: stirring at 50° C. for 12 h.
4. The preparation method according to claim 1, characterized in that: In step 2), the bismuth salt is bismuth neodecanoate.
5. The preparation method according to claim 1, characterized in that: In step 2), the amount of the bismuth salt added is 0.5-1 g, the amount of SPNTs added is 50-100 mg, and the volume of ethanol is 10 mL.
6. The preparation method according to claim 1, characterized in that: In step 2), the stirring time is 10 to 12 hours.
7. The preparation method according to claim 1, characterized in that: In step 2), the drying condition is: drying at 80° C. for 10 to 12 hours.
8. The preparation method according to claim 1, characterized in that: In step 2), the calcination conditions are: calcination at 550°C to 850°C for 2h, and a heating rate of 5°C / min.
9. Use of the CNTs@Bi electrocatalytic material prepared by the preparation method according to any one of claims 1 to 8 in the electrocatalytic reduction of carbon dioxide to synthesize formic acid.
10. The use according to claim 9, characterized in that: The method is as follows: using an H-type electrolytic cell and a three-electrode working system, taking 0.5M KHCO3 as the electrolyte, injecting the electrolyte into the cathode chamber and the anode chamber respectively, and passing carbon dioxide into the cathode chamber for 30 minutes to saturate it; Carbon paper with CNTs@Bi electrocatalytic material added was used as the working electrode, platinum mesh as the counter electrode, and Ag / AgCl as the reference electrode to electrocatalyze the reduction of carbon dioxide to synthesize formic acid.