Carbon-based catalyst and preparation method thereof
By using livestock manure to prepare biochar and mix it with metal compounds to calcinate, the problems of high cost and poor performance of existing carbon-based catalysts are solved, efficient electrocatalytic reduction of carbon dioxide and stability improvement are achieved, and the application of ECR technology is promoted.
Patent Information
- Application Number
- CN202510393204.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-31
- Publication Date
- 2025-07-04
AI Technical Summary
The existing carbon-based catalyst preparation methods are costly, cumbersome, low atomic utilization, and expensive commercial catalysts and poor performance, which limits the large-scale application of ECR technology.
Livestock manure is used as carbon-based material to prepare biochar through hydrothermal reaction, mixed with copper acetylacetonate, potassium hydroxide and urea, and calcined under an inert gas environment, and copper nanoparticles are prepared in situ to form the carbon-based catalyst Cu-NB.
The preparation cost of the catalyst is reduced, the atomic utilization rate is improved, the performance and stability of the catalyst is improved, and the efficient electrocatalytic reduction of carbon dioxide is achieved, with high electrolytic efficiency and product selectivity.
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Figure CN120250027A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of catalyst preparation, and particularly relates to a carbon-based catalyst and a preparation method thereof. Background Art
[0002] To address the carbon dioxide issue, over the past few decades, many carbon dioxide resource utilization methods have been developed. Among them, the electrocatalytic reduction of carbon dioxide (ECR) technology has become a key technology for carbon dioxide resource utilization due to its higher energy utilization efficiency and cycle stability in renewable energy-driven carbon emission reduction technologies. ECR can convert CO2 into different types of high-value fuels and chemicals: basic chemical raw materials such as CO, natural gas components such as methane, key industrial raw materials such as ethylene and ethanol, and high-value chemicals such as propane and propanol, thereby effectively resource-utilizing CO2.
[0003] In the past decade, existing ECR technologies have achieved extensive breakthroughs and significant progress in synthesis, structural design, performance optimization, and practical applications. In recent years, great efforts have been made in using metal-based catalysts for ECR to improve the catalytic activity of carbon-containing products in ECR, thus developing various catalyst design methods, such as surface oxidation state, chemical composition, particle size, crystal plane, coordination structure, grain boundary, and reaction microenvironment. It is worth noting that compared with pure metal catalysts, carbon-based metal catalysts have performance improvement and cost advantages. Existing research and technologies show that carbon-based metal catalysts have significantly improved CO2 electroreduction activity and selectivity at the three-phase boundary, and the increased surface area of the carbon support helps to disperse metal nanoparticles, improving the diffusion and adsorption of CO2 on the catalyst surface, thereby making the contact between active sites and reaction molecules more effective. In addition, heteroatoms such as N or O doped in the carbon carrier can interact with metal nanoparticles to stabilize them on the carbon matrix. The N-doped carbon matrix can promote C-C coupling due to its strong electron-withdrawing property. At the same time, the addition of a carbon-based material in the catalyst reduces the overall metal usage and cost. Therefore, carbon-based metal catalysts are considered excellent catalysts suitable for ECR technology.
[0004] Although significant achievements have been made in the preparation of various carbon-based catalysts in the prior art, improving the performance and reducing the cost of carbon-based catalysts remain a challenge. Currently, the use of carbon-based catalysts is often limited to (1) chemical directed synthesis, (2) directly adding metal nanoparticles to carbon-based materials, or (3) commercial procurement methods.
[0005] (1) The directional synthesis of chemical raw materials has a high cost, a cumbersome process, and a high cost, which limits the generalizability of the materials. The main synthesis steps of existing high-efficiency ECR carbon-based catalysts are to first directionally synthesize MOF (Metal-Organic Frameworks) and then prepare it by pyrolysis and other methods. The synthesis of MOF requires the preparation of ZIF (Zeolitic imidazolate framework) as a precursor, and the synthesis route requires multiple steps. Its important raw material, 2-methylimidazole, has strong carcinogenicity and potential harm to the environment.
[0006] (2) Metal nanoparticles are directly added to the carbon-based material by ball milling. The preparation process of metal nanoparticles is complex, with a low yield, low atomic utilization rate, and high synthesis cost.
[0007] (3) Commercially mass-produced carbon-supported copper catalysts are expensive (for example, brand: Premetek, price is 1990 yuan / g). The low heteroatom content results in poor performance, which greatly limits large-scale production. Summary of the Invention
[0008] The purpose of the present invention is to provide a carbon-based catalyst and its preparation method, which uses livestock manure as the raw material of the carbon-based material to in-situ prepare copper nanoparticles, can reduce costs, simplify the preparation process, and improve the atomic utilization rate.
[0009] In order to achieve the above invention purpose, the present invention provides the following technical solutions:
[0010] The present invention provides a preparation method of a carbon-based catalyst, comprising the following steps:
[0011] (1) Preparation of biochar: Hydrothermally react livestock manure to obtain biochar;
[0012] (2) Preparation of the carbon-based catalyst: Mix and grind copper acetylacetonate, potassium hydroxide, urea, and biochar, and then calcine in an inert gas environment to obtain the carbon-based catalyst Cu-NB.
[0013] Preferably, the livestock manure in step (1) is one or several of chicken manure and pig manure.
[0014] Preferably, the temperature of the hydrothermal reaction in step (1) is 200-400°C;
[0015] The time of the hydrothermal reaction in step (1) is 0.5-2 h.
[0016] Preferably, the mass ratio of copper acetylacetonate, potassium hydroxide, urea, and biochar in step (2) is 0.1-4:0.8-1.2:0-3:0.3-0.8.
[0017] Preferably, the inert gas in step (2) is nitrogen.
[0018] Preferably, the heating rate of calcination in step (2) is 3 - 7 °C / min;
[0019] The temperature of the calcination is 600 - 1000 °C;
[0020] The time of the calcination is 1 - 3 h.
[0021] The present invention also provides a carbon-based catalyst obtained by the preparation method of the carbon-based catalyst described above.
[0022] The present invention has the following beneficial effects:
[0023] 1. The present invention uses livestock manure as the raw material of the carbon-based material, while resource-utilizing livestock manure, obtaining a high-value ECR catalyst, and providing a composite treatment technology for the problems of solid waste pollution and carbon neutrality.
[0024] 2. The preparation method of the present invention effectively reduces the raw material and preparation cost of the metal nanoparticle carbon-based catalyst, and improves the atomic utilization rate. The addition of urea further increases the nitrogen content of the catalyst, improves the surface polarity of the biochar, acts with the copper nanoparticles, and further improves the performance and stability. The carbon-based catalyst material is synthesized by a simple and effective method, and has strong popularization potential.
[0025] 3. The present invention replaces the high-value and highly polluting organic raw material with livestock manure, reducing the possibility of environmental pollution.
[0026] 4. The metal nanoparticle carbon-based catalyst synthesized by the present invention has excellent performance, high electrolysis efficiency and product selectivity, and high stability at the same time. Description of the Drawings
[0027] Figure 1 SEM image of the carbon-based catalyst Cu-NB-2000 of Example 10;
[0028] Figure 2 TEM image of the carbon-based catalyst Cu-NB-2000 of Example 10;
[0029] Figure 3 EDS element distribution map of the carbon-based catalyst Cu-NB-2000 of Example 10;
[0030] Figure 4 XRD patterns of the carbon-based catalyst Cu-NB-2000 of Example 10, the carbon-based catalyst Cu-B-2000 of Example 12, and the carbon-based catalyst Cu-NC-2000 of Comparative Example 1;
[0031] Figure 5 XPS spectrum of the carbon-based catalyst Cu-NB-2000 of Example 10;
[0032] Figure 6 Steady-state time-varying curve of carbon dioxide electrolysis of the carbon-based catalyst Cu-NB-2000 of Example 10. Detailed implementation manners
[0033] The present invention provides a preparation method of a carbon-based catalyst, comprising the following steps:
[0034] (1) Preparation of biochar: Hydrothermal reaction is carried out on livestock manure to obtain biochar;
[0035] (2) Preparation of carbon-based catalyst: Copper acetylacetonate, potassium hydroxide, urea and biochar are mixed and ground, and then calcined in an inert gas environment to obtain the carbon-based catalyst Cu-NB.
[0036] In the present invention, the livestock manure in step (1) is preferably one or more of chicken manure, pig manure and horse manure.
[0037] In the present invention, the temperature of the hydrothermal reaction in step (1) is preferably 200-400 °C, more preferably 220-380 °C, and even more preferably 250-350 °C.
[0038] In the present invention, the time of the hydrothermal reaction in step (1) is preferably 0.5-2 h, more preferably 0.7-1.8 h, and even more preferably 1-1.5 h.
[0039] Aiming at the disadvantages and problems of the existing carbon-based ECR catalyst preparation technology, the present invention first screens the raw materials of carbon-based materials, and the screening conditions are as follows: low cost, can be obtained or prepared on a large scale; low toxicity, low harm to the environment, and low treatment cost; high content of heteroatoms such as N and O; the present invention selects livestock manure biomass as the carbon-based material, and carries out hydrothermal reaction in a hydrothermal autoclave at a specific temperature to obtain a bio-carbon-based raw material.
[0040] In the present invention, the mass ratio of copper acetate pyruvate, potassium hydroxide, urea and biochar in step (2) is preferably 0.1-4:0.8-1.2:0-3:0.3-0.8, more preferably 0.2-3:0.9-1.1:0.5-2.5:0.4-0.7; even more preferably 0.5-2:1:1-2:0.5-0.6.
[0041] In the present invention, the inert gas in step (2) is preferably nitrogen.
[0042] In the present invention, the heating rate of the calcination in step (2) is preferably 3 - 7 °C / min, more preferably 3.5 - 6.5 °C / min, and still more preferably 4 - 6 °C / min.
[0043] In the present invention, the temperature of the calcination is preferably 600 - 1000 °C, more preferably 650 - 950 °C, and still more preferably 700 - 900 °C.
[0044] In the present invention, the time of the calcination is preferably 1 - 3 h, more preferably 1.2 - 2.8 h, and still more preferably 1.5 - 2.5 h.
[0045] In the present invention, after the calcination, washing, filtration and drying are sequentially carried out to obtain the carbon-based catalyst Cu-NB.
[0046] In the present invention, the solvent for washing is preferably ultrapure water.
[0047] In the present invention, the temperature of the drying is preferably 40 - 80 °C, more preferably 45 - 75 °C, and still more preferably 50 - 70 °C.
[0048] In the present invention, the time of the drying is preferably 3 - 8 h, more preferably 4 - 7 h, and still more preferably 5 - 6 h.
[0049] Compared with the prior art, the present preparation method in-situ prepares copper nanoparticles, without the need to separately prepare copper nanoparticles at high cost, thereby effectively reducing the cost, simplifying the preparation process, and improving the atomic utilization rate. The addition of urea further increases the nitrogen content of the catalyst, improves the surface polarity of the biochar, and acts with the copper nanoparticles to further improve the performance and stability.
[0050] The present invention also provides a carbon-based catalyst obtained by the preparation method of the carbon-based catalyst described above.
[0051] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the protection scope of the present invention.
[0052] Example 1
[0053] Biochar preparation: Pig manure is placed in a hydrothermal autoclave and subjected to a hydrothermal reaction at 300 °C for 1 h to obtain biochar.
[0054] Preparation of carbon-based catalyst: Take 100 mg of copper acetylacetonate, 1.0 g of potassium hydroxide, 1.5 g of urea and 0.5 g of biochar and mix them by grinding (where the mass ratio of copper acetylacetonate, potassium hydroxide, urea and biochar is 0.1:1:1.5:0.5). Then, under a nitrogen atmosphere, calcine at 800 °C for 2 hours at a heating rate of 5 °C / min. After calcination, wash and filter successively with ultrapure water, and then dry at 60 °C for 5 h to obtain the carbon-based catalyst Cu-NB-100 (where 100 represents the amount of copper acetylacetonate, in milligrams).
[0055] Example 2
[0056] Preparation of biochar: Place pig manure in a hydrothermal reactor and carry out hydrothermal reaction at 300 °C for 1 h to obtain biochar.
[0057] Preparation of carbon-based catalyst: Take 200 mg of copper acetylacetonate, 1.0 g of potassium hydroxide, 1.5 g of urea and 0.5 g of biochar and mix them by grinding (where the mass ratio of copper acetylacetonate, potassium hydroxide, urea and biochar is 0.2:1:1.5:0.5). Then, under a nitrogen atmosphere, calcine at 800 °C for 2 hours at a heating rate of 5 °C / min. After calcination, wash and filter successively with ultrapure water, and then dry at 60 °C for 5 h to obtain the carbon-based catalyst Cu-NB-200 (where 200 represents the amount of copper acetylacetonate, in milligrams).
[0058] Example 3
[0059] Preparation of biochar: Place pig manure in a hydrothermal reactor and carry out hydrothermal reaction at 300 °C for 1 h to obtain biochar.
[0060] Preparation of carbon-based catalyst: Take 300 mg of copper acetylacetonate, 1.0 g of potassium hydroxide, 1.5 g of urea and 0.5 g of biochar and mix them by grinding (where the mass ratio of copper acetylacetonate, potassium hydroxide, urea and biochar is 0.3:1:1.5:0.5). Then, under a nitrogen atmosphere, calcine at 800 °C for 2 hours at a heating rate of 5 °C / min. After calcination, wash and filter successively with ultrapure water, and then dry at 60 °C for 5 h to obtain the carbon-based catalyst Cu-NB-300 (where 300 represents the amount of copper acetylacetonate, in milligrams).
[0061] Example 4
[0062] Preparation of biochar: Place pig manure in a hydrothermal reactor and carry out hydrothermal reaction at 300 °C for 1 h to obtain biochar.
[0063] Preparation of carbon-based catalyst: Take 400 mg of copper acetylacetonate, 1.0 g of potassium hydroxide, 1.5 g of urea and 0.5 g of biochar and mix and grind them (where the mass ratio of copper acetylacetonate, potassium hydroxide, urea and biochar is 0.4:1:1.5:0.5). Then, under a nitrogen atmosphere, calcine at 800 °C for 2 hours at a heating rate of 5 °C / min. After calcination, wash and filter successively with ultrapure water, and then dry at 60 °C for 5 h to obtain the carbon-based catalyst Cu-NB-400 (where 400 represents the amount of copper acetylacetonate, in milligrams).
[0064] Example 5
[0065] Preparation of biochar: Place pig manure in a hydrothermal reactor and carry out hydrothermal reaction at 300 °C for 1 h to obtain biochar.
[0066] Preparation of carbon-based catalyst: Take 500 mg of copper acetylacetonate, 1.0 g of potassium hydroxide, 1.5 g of urea and 0.5 g of biochar and mix and grind them (where the mass ratio of copper acetylacetonate, potassium hydroxide, urea and biochar is 0.5:1:1.5:0.5). Then, under a nitrogen atmosphere, calcine at 800 °C for 2 hours at a heating rate of 5 °C / min. After calcination, wash and filter successively with ultrapure water, and then dry at 60 °C for 5 h to obtain the carbon-based catalyst Cu-NB-500 (where 500 represents the amount of copper acetylacetonate, in milligrams).
[0067] Example 6
[0068] Preparation of biochar: Place pig manure in a hydrothermal reactor and carry out hydrothermal reaction at 300 °C for 1 h to obtain biochar.
[0069] Preparation of carbon-based catalyst: Take 800 mg of copper acetylacetonate, 1.0 g of potassium hydroxide, 3 g of urea and 0.5 g of biochar and mix and grind them (where the mass ratio of copper acetylacetonate, potassium hydroxide, urea and biochar is 0.8:1:3:0.5). Then, under a nitrogen atmosphere, calcine at 800 °C for 2 hours at a heating rate of 5 °C / min. After calcination, wash and filter successively with ultrapure water, and then dry at 60 °C for 5 h to obtain the carbon-based catalyst Cu-NB-800 (where 800 represents the amount of copper acetylacetonate, in milligrams).
[0070] Example 7
[0071] Preparation of biochar: Place pig manure in a hydrothermal reactor and carry out hydrothermal reaction at 300 °C for 1 h to obtain biochar.
[0072] Preparation of carbon-based catalyst: Take 1000 mg of copper acetylacetonate, 1.0 g of potassium hydroxide, 3 g of urea and 0.5 g of biochar and mix them by grinding (where the mass ratio of copper acetylacetonate, potassium hydroxide, urea and biochar is 1:1:3:0.5). Then, under a nitrogen atmosphere, calcine at 800 °C for 2 hours at a heating rate of 5 °C / min. After calcination, wash and filter successively with ultrapure water, and then dry at 60 °C for 5 h to obtain the carbon-based catalyst Cu-NB-1000 (where 1000 represents the amount of copper acetylacetonate, in milligrams).
[0073] Example 8
[0074] Preparation of biochar: Place pig manure in a hydrothermal reactor and carry out hydrothermal reaction at 300 °C for 1 h to obtain biochar.
[0075] Preparation of carbon-based catalyst: Take 1200 mg of copper acetylacetonate, 1.0 g of potassium hydroxide, 3 g of urea and 0.5 g of biochar and mix them by grinding (where the mass ratio of copper acetylacetonate, potassium hydroxide, urea and biochar is 1.2:1:3:0.5). Then, under a nitrogen atmosphere, calcine at 800 °C for 2 hours at a heating rate of 5 °C / min. After calcination, wash and filter successively with ultrapure water, and then dry at 60 °C for 5 h to obtain the carbon-based catalyst Cu-NB-1200 (where 1200 represents the amount of copper acetylacetonate, in milligrams).
[0076] Example 9
[0077] Preparation of biochar: Place pig manure in a hydrothermal reactor and carry out hydrothermal reaction at 300 °C for 1 h to obtain biochar.
[0078] Preparation of carbon-based catalyst: Take 1500 mg of copper acetylacetonate, 1.0 g of potassium hydroxide, 3 g of urea and 0.5 g of biochar and mix them by grinding (where the mass ratio of copper acetylacetonate, potassium hydroxide, urea and biochar is 1.5:1:3:0.5). Then, under a nitrogen atmosphere, calcine at 800 °C for 2 hours at a heating rate of 5 °C / min. After calcination, wash and filter successively with ultrapure water, and then dry at 60 °C for 5 h to obtain the carbon-based catalyst Cu-NB-1500 (where 1500 represents the amount of copper acetylacetonate, in milligrams).
[0079] Example 10
[0080] Preparation of biochar: Place pig manure in a hydrothermal reactor and carry out hydrothermal reaction at 300 °C for 1 h to obtain biochar.
[0081] Preparation of carbon-based catalyst: Take 2000 mg of copper acetylacetonate, 1.0 g of potassium hydroxide, 3 g of urea and 0.5 g of biochar and mix them by grinding (where the mass ratio of copper acetylacetonate, potassium hydroxide, urea and biochar is 2:1:3:0.5). Under a nitrogen atmosphere, then calcine at 800 °C for 2 hours at a heating rate of 5 °C / min under a nitrogen atmosphere. After calcination, wash and filter successively with ultrapure water, and then dry at 60 °C for 5 h to obtain the carbon-based catalyst Cu-NB-2000 (where 2000 represents the amount of copper acetylacetonate, in milligrams).
[0082] Example 11
[0083] Preparation of biochar: Put pig manure in a hydrothermal reactor and carry out hydrothermal reaction at 300 °C for 1 h to obtain biochar.
[0084] Preparation of carbon-based catalyst: Take 4000 mg of copper acetylacetonate, 1.0 g of potassium hydroxide, 3 g of urea and 0.5 g of biochar and mix them by grinding (where the mass ratio of copper acetylacetonate, potassium hydroxide, urea and biochar is 4:1:3:0.5). Then, under a nitrogen atmosphere, calcine at 800 °C for 2 hours at a heating rate of 5 °C / min. After calcination, wash and filter successively with ultrapure water, and then dry at 60 °C for 5 h to obtain the carbon-based catalyst Cu-NB-4000 (where 4000 represents the amount of copper acetylacetonate, in milligrams).
[0085] Example 12
[0086] Preparation of biochar: Put pig manure in a hydrothermal reactor and carry out hydrothermal reaction at 300 °C for 1 h to obtain biochar.
[0087] Preparation of carbon-based catalyst: Take 2000 mg of copper acetylacetonate, 1.0 g of potassium hydroxide and 0.5 g of biochar and mix them by grinding (where the mass ratio of copper acetylacetonate, potassium hydroxide, urea and biochar is 2:1:0:0.5). Then, under a nitrogen atmosphere, calcine at 800 °C for 2 hours at a heating rate of 5 °C / min. After calcination, wash and filter successively with ultrapure water, and then dry at 60 °C for 5 h to obtain the carbon-based catalyst Cu-B-2000 (where 2000 represents the amount of copper acetylacetonate, in milligrams).
[0088] Example 13
[0089] Preparation of biochar: Put chicken manure in a hydrothermal reactor and carry out hydrothermal reaction at 300 °C for 1 h to obtain biochar.
[0090] Preparation of carbon-based catalyst: Take 2000 mg of copper acetylacetonate, 1.0 g of potassium hydroxide, 3 g of urea and 0.5 g of biochar and mix them by grinding (where the mass ratio of copper acetylacetonate, potassium hydroxide, urea and biochar is 2:1:3:0.5). Then, under a nitrogen atmosphere, calcine at 800 °C for 2 hours at a heating rate of 5 °C / min. After calcination, wash and filter successively with ultrapure water, and then dry at 60 °C for 5 h to obtain the carbon-based catalyst Cu-NB-2000 (where 2000 represents the amount of copper acetylacetonate, in milligrams).
[0091] Example 14
[0092] Preparation of biochar: Take horse manure and place it in a hydrothermal reactor for hydrothermal reaction at 300 °C for 1 h to obtain biochar.
[0093] Preparation of carbon-based catalyst: Take 2000 mg of copper acetylacetonate, 1.0 g of potassium hydroxide, 3 g of urea and 0.5 g of biochar and mix them by grinding (where the mass ratio of copper acetylacetonate, potassium hydroxide, urea and biochar is 2:1:3:0.5). Then, under a nitrogen atmosphere, calcine at 800 °C for 2 hours at a heating rate of 5 °C / min. After calcination, wash and filter successively with ultrapure water, and then dry at 60 °C for 5 h to obtain the carbon-based catalyst Cu-NB-2000 (where 2000 represents the amount of copper acetylacetonate, in milligrams).
[0094] Comparative Example 1
[0095] Preparation of carbon-based catalyst: Take 2000 mg of copper acetylacetonate, 1.0 g of potassium hydroxide, 3 g of urea and 0.5 g of activated carbon and mix them by grinding (where the mass ratio of copper acetylacetonate, potassium hydroxide, urea and activated carbon is 2:1:3:0.5). Then, under a nitrogen atmosphere, calcine at 800 °C for 2 hours at a heating rate of 5 °C / min. After calcination, wash and filter successively with ultrapure water, and then dry at 60 °C for 5 h to obtain the carbon-based catalyst Cu-NC-2000 (where 2000 represents the amount of copper acetylacetonate, in milligrams).
[0096] Result analysis:
[0097] The carbon-based catalyst Cu-NB-2000 obtained in Example 10 was scanned by scanning electron microscopy, and its SEM image is as Figure 1 shown.
[0098] From Figure 1 it can be seen that the carbon-based catalyst Cu-NB-2000 shows more and smaller pores, and the diameter of most pores is 15 - 50 nm, belonging to the mesoporous range.
[0099] The carbon-based catalyst Cu-NB-2000 obtained in Example 10 was scanned by transmission electron microscopy, and its TEM image is as follows Figure 2 shown.
[0100] It can be seen from Figure 2 that the Cu nanoparticles are well dispersed on the biochar substrate, and the particle size is mainly concentrated between 3 and 5 nm.
[0101] Furthermore, the carbon-based catalyst Cu-NB-2000 obtained in Example 10 was analyzed by EDS (energy-dispersive X-ray spectroscopy), and its EDS element distribution map is as follows Figure 3 shown.
[0102] Figure 3 This further confirmed the relatively uniform distribution of copper, nitrogen, oxygen, and carbon elements on the biochar surface.
[0103] The carbon-based catalyst Cu-NB-2000 obtained in Example 10, the carbon-based catalyst Cu-B-2000 obtained in Example 12, and the carbon-based catalyst Cu-NC-2000 obtained in Comparative Example 1 were analyzed by X-ray diffraction, and their XRD patterns (X-ray diffraction patterns) are as follows Figure 4 shown.
[0104] It can be seen from Figure 4 that the XRD pattern of the carbon-based catalyst Cu-NB-2000 obtained in Example 10 shows characteristic peaks at 43.3°, 50.4°, and 74.1°, corresponding to the (111), (100), and (110) planes of copper, respectively. This indicates that the carbon-based catalyst Cu-NB-2000 has a high loading of nano-copper particles, which is consistent with the extensive distribution of copper elements observed in the EDS map. In contrast, the XRD pattern of the control group using activated carbon as the carbon source shows weaker peaks corresponding to the (111), (100), and (110) planes of copper, indicating a lower copper loading.
[0105] The carbon-based catalyst Cu-NB-2000 obtained in Example 10 was analyzed by X-ray photoelectron spectrometer, and its XPS pattern (X-ray photoelectron spectroscopy pattern) is as follows Figure 5 shown.
[0106] It can be seen from Figure 5As can be seen, the N 1s XPS spectrum of the carbon-based catalyst Cu-NB-2000 shows five peaks at 405.7 eV, 401.4 eV, 400.0 eV, 399.0 eV, and 397.8 eV, which can be attributed to oxidized N, graphitic N, pyrrolidine N, Cu-N, and pyridine N, respectively. Pyridine N accounts for a large proportion of the total nitrogen content and also shows a unique Cu-N coordination structure. Compared with other forms of nitrogen, the nitrogen atom in pyridine nitrogen can act as a Lewis base, more easily provide lone pair electrons and form coordination bonds with metal ions.
[0107] Performance test:
[0108] In a flow cell configuration with 1 mol / L KOH as the electrolyte, the activity and selectivity of the carbon-based catalyst Cu-NB-2000 obtained in Example 10 were evaluated. At a potential of -0.91 V versus the reversible hydrogen electrode (RHE), the steady-state time-varying curve of carbon dioxide electrolysis was recorded, as Figure 6 shown.
[0109] As can be seen from Figure 6 , at -0.91 V (versus RHE), the FE CO2 (electrochemical conversion efficiency of CO2) of the material reached 87.14%, and the FE C2+ (electrochemical conversion efficiency of C 2+ ) value was 41.37%. During the 10 h stability test, the performance and structure of the carbon-based material did not change significantly.
[0110] The performance of the carbon catalysts Cu-NB-2000 obtained in Example 10, Example 13, and Example 14 was compared, and the results are as follows:
[0111] When using pig manure as the carbon-based raw material, the structure of the carbon catalyst and its performance in converting carbon dioxide reach the best;
[0112] When using chicken manure as the raw material, after treatment, due to the smaller particle size of chicken manure, the porosity of chicken manure biochar is lower than that of pig manure biochar. The FE CO2 of the carbon-based material is 74.52%, and the FE C2+ value is 33.12%.
[0113] When using horse manure as the raw material, due to the relatively high cellulose content in horse manure, the elemental composition of the prepared biochar is mainly carbon, and the heteroatom content is relatively low. The FE CO2 of the carbon-based material is 71.84%, and the FE C2+ value is 30.46%.
[0114] As can be seen from the above embodiments, the present invention provides a carbon-based catalyst and a preparation method thereof, comprising the following steps: Preparation of biochar: subjecting livestock manure to hydrothermal reaction to obtain biochar; Preparation of carbon-based catalyst: mixing cupric acetylacetonate, potassium hydroxide, urea and biochar and grinding them, and then calcining in an inert gas environment to obtain the carbon-based catalyst Cu-NB. The present invention uses livestock manure as the raw material for the carbon-based material, and while recycling livestock manure, a high-value ECR catalyst is obtained, providing a composite treatment technology for the problems of solid waste pollution and carbon neutrality. The preparation method of the present invention effectively reduces the raw materials and preparation costs of the metal nanoparticle carbon-based catalyst and improves the atomic utilization rate. The addition of urea further increases the nitrogen content of the catalyst, improves the surface polarity of the biochar, acts with copper nanoparticles, and further improves the performance and stability. The carbon-based catalyst material is synthesized by a simple and effective method and has strong popularization potential. The present invention replaces the high-value and highly polluting organic raw materials with livestock manure, reducing the possibility of environmental pollution. The synthesized metal nanoparticle carbon-based catalyst of the present invention has excellent performance, and the FE CO2 of the carbon-based material can reach 87.14%, and the FE C2+ value is 41.37%, with high electrolysis efficiency and product selectivity, and high stability at the same time.
[0115] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.
Claims
1. A preparation method of a carbon-based catalyst, characterized in that, It includes the following steps: (1) Preparation of biochar: subjecting livestock manure to hydrothermal reaction to obtain biochar; (2) Preparation of carbon-based catalyst: mixing copper acetylacetonate, potassium hydroxide, urea and biochar, grinding them, and then calcining them in an inert gas environment to obtain the carbon-based catalyst Cu-NB.
2. The preparation method of a carbon-based catalyst according to claim 1, wherein, In the step (1), the livestock manure is one or more of chicken manure, pig manure and horse manure.
3. The preparation method of a carbon-based catalyst according to claim 1, characterized in that, In the step (1), the temperature of the hydrothermal reaction is 200-400 °C; In the step (1), the time of the hydrothermal reaction is 0.5-2 h.
4. The preparation method of a carbon-based catalyst according to claim 1, characterized in that, In the step (2), the mass ratio of copper acetylacetonate, potassium hydroxide, urea and biochar is 0.1-4:0.8-1.2:0-3:0.3-0.
8.
5. The preparation method of a carbon-based catalyst according to claim 1, characterized in that In the step (2), the inert gas is nitrogen.
6. The preparation method of a carbon-based catalyst according to claim 1, characterized in that, In the step (2), the heating rate of the calcination is 3-7 °C / min; The temperature of the calcination is 600-1000 °C; The time of the calcination is 1-3 h.
7. A carbon-based catalyst obtained by the preparation method of the carbon-based catalyst according to any one of claims 1-6.