Copper-cerium nanoparticle catalyst for synthesizing urea through electrocatalytic reduction of carbon dioxide and nitrogen and preparation method and application of copper-cerium nanoparticle catalyst
By preparing copper cerium nanoparticle catalysts, the problem of weak catalytic performance of existing copper nanoparticle catalysts is solved, and the yield and Faraday efficiency of urea are significantly improved, achieving more efficient urea synthesis.
Patent Information
- Application Number
- CN202510285239.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-11
- Publication Date
- 2025-06-06
AI Technical Summary
The existing copper nanoparticle catalysts for electrocatalytic reduction of carbon dioxide and nitrogen to synthesize urea have weak catalytic performance, and the product yield and Faraday efficiency are low.
A copper cerium nanoparticle catalyst is used to prepare a copper cerium nanoparticle catalyst by dissolving Ce(CH3COO)3·xH2O and Cu(CH3COO)2 in triethylene glycol, combining polyvinylpyrrolidone, and after stirring, heating, washing, centrifugation and drying.
The yield and Faraday efficiency of urea are significantly improved, and the copper cerium nanoparticle catalyst has a high selectivity for urea synthesis.
Smart Images
Figure CN120099575A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of electrocatalysis technology, and specifically relates to a copper-cerium nanoparticle catalyst for electrocatalytic reduction of carbon dioxide and nitrogen to synthesize urea, and a preparation method and application thereof. Background Art
[0002] With the continuous growth of global energy demand and the increasing awareness of environmental protection, the search for efficient and sustainable energy conversion and storage technologies has become a hot topic in current scientific and technological research. Among them, electrocatalytic reduction of carbon dioxide technology has attracted much attention because it can convert greenhouse gases into valuable chemicals. As an important nitrogen fertilizer raw material and chemical raw material, urea has problems such as high energy consumption and high pollution in its traditional production process. Therefore, the use of electrocatalytic synergistic reduction of carbon dioxide and nitrogen technology to synthesize urea can not only help realize the resource utilization of carbon dioxide, but also reduce the energy consumption and environmental pollution of urea production.
[0003] In the study of electrocatalytic reduction of carbon dioxide and nitrogen to synthesize urea, the performance of the catalyst is the key factor determining the reaction efficiency and product selectivity. Currently, copper nanoparticles are mostly used as electrocatalysts, and research on their catalytic performance has made some progress, but their catalytic performance is weak, and the product yield and Faraday efficiency are still low. Summary of the invention
[0004] The present disclosure aims to solve at least one of the technical problems existing in the prior art, and provides a copper-cerium nanoparticle catalyst for electrocatalytic reduction of carbon dioxide and nitrogen to synthesize urea, and a preparation method and application thereof.
[0005] In one aspect of the present disclosure, there is provided a method for preparing a copper-cerium nanoparticle catalyst for electrocatalytic reduction of carbon dioxide and nitrogen to synthesize urea, the preparation method comprising:
[0006] Ce(CH 3 COO 3 ·xH 2 O is dissolved in triethylene glycol to form a first solution;
[0007] Dissolving Cu(CH3COO)2 in triethylene glycol to form a second solution;
[0008] Polyvinyl pyrrolidone is dissolved in triethylene glycol, and the mixture is heated to a first temperature after stirring at room temperature, and the first solution is added. When the mixture is stirred and heated to a second temperature, the second solution is added. The stirred and cooled solution is washed, centrifuged, and dried to obtain a copper-cerium nanoparticle catalyst.
[0009] Optionally, Ce(CH 3 COO 3 ·xH 2O is dissolved in triethylene glycol, the Ce(CH 3 COO 3 ·xH 2 The content of O is 90-100 parts by mass, and the content of triethylene glycol is 5-10 parts by volume.
[0010] Optionally, in the presence of Cu(CH 3 COO 2 Dissolved in triethylene glycol, the Cu(CH 3 COO 2 The content of is 300-400 parts by mass, and the content of triethylene glycol is 5-10 parts by volume.
[0011] Optionally, when polyvinyl pyrrolidone is dissolved in triethylene glycol, the content of the polyvinyl pyrrolidone is 200-300 parts by mass, and the content of the triethylene glycol is 50-100 parts by volume.
[0012] Optionally, the first temperature is 170-210°C.
[0013] Optionally, the stirring time after adding the second solution is 10-20 minutes.
[0014] Optionally, the second temperature is above 240°C.
[0015] Optionally, the drying process is performed for 10-14 hours.
[0016] In another aspect of the present disclosure, a copper-cerium nanoparticle catalyst is provided. The copper-cerium nanoparticle catalyst is prepared by the preparation method described above.
[0017] In another aspect of the present disclosure, a copper-cerium nanoparticle catalyst is provided. The copper-cerium nanoparticle catalyst is used in the electrocatalytic reduction of carbon dioxide and nitrogen to synthesize urea.
[0018] The present invention provides a copper-cerium nanoparticle catalyst for electrocatalytic reduction of carbon dioxide and nitrogen to synthesize urea, and a preparation method and application thereof. The preparation method of the copper-cerium nanoparticle catalyst comprises: 3 COO 3 ·xH 2 O is dissolved in triethylene glycol to form a first solution; Cu(CH 3 COO 2The method comprises dissolving polyvinyl pyrrolidone in triethylene glycol to form a second solution; dissolving polyvinyl pyrrolidone in triethylene glycol, stirring at room temperature and then heating to a first temperature, adding the first solution, stirring and heating to a second temperature, adding the second solution, washing the solution after stirring and cooling, centrifuging, and drying to obtain a copper-cerium nanoparticle catalyst. The present invention adopts a simple one-step reduction method to synthesize a copper-cerium nanoparticle catalyst, and the preparation process is simple. The synthesized copper-cerium nanocatalyst has high selectivity for urea synthesis and can effectively improve the urea yield and Faraday efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 It is a flowchart of a method for preparing a copper-cerium nanoparticle catalyst according to a specific embodiment of the present disclosure;
[0020] Figure 2 is a SEM image of the copper-cerium nanoparticles of Example 1 of the present disclosure;
[0021] Figure 3 This is a high-resolution TEM image of the copper-cerium nanoparticles of Example 1 of the present disclosure;
[0022] Figure 4 High-resolution XRD patterns of the copper-cerium nanoparticles of Example 1 and the copper nanoparticles of Comparative Example 1 of the present disclosure;
[0023] Figure 5 This is a comparison diagram of LSV curves of carbon paper CP and copper-cerium nanoparticles in Example 1 of the present disclosure under nitrogen and carbon dioxide;
[0024] Figure 6 This is a comparison diagram of LSV curves of the copper-cerium nanoparticles of Example 1 of the present disclosure and the copper nanoparticles of Comparative Example 1 under nitrogen and carbon dioxide;
[0025] Figure 7 This is a comparison diagram of LSV curves of the copper-cerium nanoparticles of Example 1 of the present disclosure under argon and carbon dioxide + nitrogen;
[0026] Figure 8 The current-time (It) curve of the constant voltage electrolysis of the copper-cerium nanoparticles of Example 1 of the present disclosure under nitrogen and carbon dioxide atmospheres;
[0027] Fig. 9 The Faraday efficiency and urea yield of the copper-cerium nanoparticles of Example 1 of the present disclosure and the copper nanoparticles of Comparative Example 1 under the electrocatalytic synergistic reduction of nitrogen and carbon dioxide to synthesize urea are compared (-4.5 V, vs. RHE);
[0028] Fig.10 This is a comparison chart of the Faraday efficiency and urea yield at different electrolysis voltages for the electrocatalytic synergistic reduction of nitrogen and carbon dioxide to synthesize urea by copper-cerium nanoparticles in Example 1 of the present disclosure;
[0029] Fig.11 This is a SEM image of the copper nanoparticles of Comparative Example 1 of the present disclosure. DETAILED DESCRIPTION
[0030] In order to enable those skilled in the art to better understand the technical solution of the present disclosure, the present disclosure is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. It should be understood that the specific embodiments described herein are only used to explain the present disclosure and are part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.
[0031] like Figure 1 As shown, in one aspect of the present disclosure, a method S100 for preparing a copper-cerium nanoparticle catalyst for electrocatalytic reduction of carbon dioxide and nitrogen to synthesize urea is provided, which specifically comprises the following steps S110 to S130:
[0032] S110, Ce(CH 3 COO 3 ·xH 2 O is dissolved in triethylene glycol to form a first solution, which is a triethylene glycol solution of cerium acetate.
[0033] In some preferred embodiments, Ce(CH 3 COO 3 ·xH 2 O is dissolved in triethylene glycol, Ce(CH 3 COO 3 ·xH 2 The content of O is 90-100 parts by mass, for example, 90 parts by mass, 95 parts by mass, 100 parts by mass, etc. The content of triethylene glycol is 5-10 parts by volume, for example, 5 parts by volume, 7 parts by volume, 10 parts by volume, etc.
[0034] It should be noted that the units of mass parts and volume parts in step S110 can be determined according to actual needs. For example, Ce(CH 3 COO 3 ·xH 2 The content of O is 90-100 mg, and the content of triethylene glycol is 5-10 mL. At this time, 1 mass part is 1 mg and 1 volume part is 1 mL.
[0035] S120, Cu(CH 3 COO 2 The copper acetate is dissolved in triethylene glycol to form a second solution, which is a triethylene glycol solution of copper acetate.
[0036] In some preferred embodiments, when Cu(CH3 COO 2 Dissolved in triethylene glycol, the Cu(CH 3 COO 2 The content of is 300-400 parts by mass, for example, 90 parts by mass, 95 parts by mass, 100 parts by mass, etc., and the content of triethylene glycol is 5-10 parts by volume, for example, 5 parts by volume, 7 parts by volume, 10 parts by volume, etc.
[0037] Similarly, the mass fraction and volume fraction of step S120 can also be determined according to actual needs. For example, Cu(CH 3 COO 2 The content of is 90-100 mg, and the content of triethylene glycol is 5-10 mL.
[0038] It should be noted that triethylene glycol is a polar organic solvent with strong solubility, which can fully dissolve cerium acetate and copper acetate and evenly disperse them in the solution, which helps to evenly distribute copper ions and cerium ions during the reaction, thereby helping to form a copper-cerium nanoparticle catalyst with uniform particle size and uniform composition. In addition, triethylene glycol has a higher boiling point, which allows the reaction to be carried out at a relatively high temperature without causing the reaction system to be unstable due to the rapid volatilization of the solvent. At higher temperatures, the chemical reaction rate is usually accelerated, which is conducive to the chemical reaction between ions and the formation of nanoparticles. Furthermore, triethylene glycol can be adsorbed on the surface of nanoparticles, plays a role similar to that of a surfactant, can reduce the surface energy of the nanoparticle surface, prevent nanoparticles from agglomerating with each other during the formation process, thereby helping to form copper-cerium nanoparticles with smaller particle size and good dispersibility.
[0039] S130, dissolving polyvinyl pyrrolidone (PVP) in triethylene glycol, stirring at room temperature and then heating to a first temperature, adding the first solution, stirring and heating to a second temperature, adding the second solution, washing, centrifuging and drying the solution after stirring and cooling to obtain a copper-cerium nanoparticle catalyst.
[0040] Specifically, in a three-necked flask, 200-300 parts by mass of PVP powder are dissolved in 50-100 parts by volume of triethylene glycol and stirred at room temperature. After that, the solution is heated to 170-210°C, the first solution is quickly added, and stirring is maintained. After that, when the system temperature is above 240°C, the second solution is quickly injected under strong magnetic stirring. After maintaining at this temperature for 10 to 20 minutes, the entire reactor is rapidly cooled to obtain a purple solution. The obtained purple solution is washed and centrifuged with acetone and ethanol (8000 to 10000rpm, 5 to 10 minutes) several times to obtain a purple-black precipitate. The precipitate is dried at high temperature for 10-14 hours in a vacuum drying furnace to obtain a dry copper-cerium nanoparticle sample.
[0041] In some preferred embodiments, polyvinyl pyrrolidone is dissolved in triethylene glycol, and the PVP powder may preferably be PVPK30 powder, and its content is preferably 200 mg, 250 mg, or 300 mg.
[0042] It should be noted that in step S130, triethylene glycol is also used as a solvent, which has good solubility for polyvinyl pyrrolidone (PVP), cerium acetate and copper acetate, and can make each reactant fully and evenly mixed in the solution. In addition, due to the presence of PVP and the surface activity of triethylene glycol, the prepared copper-cerium nanoparticles have good dispersibility, so that the interaction between the nanoparticles is small, the specific surface area is large, and more active sites can be provided, thereby significantly improving the catalytic activity and selectivity of the catalyst.
[0043] This embodiment adopts a simple one-step reduction method to synthesize copper-cerium nanoparticles. Compared with the traditional multi-step preparation process, it reduces the complicated intermediate steps and cumbersome operation procedures. It only needs to add the reactants in order and control the temperature and stirring conditions to complete the preparation of the catalyst, which reduces the difficulty of operation and time cost and improves production efficiency. In addition, this embodiment is based on the formation of oxygen vacancies in copper-cerium nanoparticles, which has a positive effect on catalytic performance, so that the copper-cerium nanoparticle catalyst exhibits more excellent catalytic performance in the electrocatalytic reduction of carbon dioxide to synthesize urea, and can effectively improve the urea yield and Faraday efficiency.
[0044] In another aspect of the present disclosure, a copper-cerium nanoparticle catalyst is provided. The copper-cerium nanoparticle catalyst is prepared by the preparation method described above.
[0045] In another aspect of the present disclosure, a copper-cerium nanoparticle catalyst is provided, and the copper-cerium nanoparticle catalyst described above is applied to the electrocatalytic reduction of carbon dioxide and nitrogen to synthesize urea.
[0046] The preparation method of copper-cerium nanoparticle catalyst will be further described below in conjunction with specific examples:
[0047] Example 1
[0048] This example provides a method for preparing a copper-cerium nanoparticle catalyst, comprising the following steps:
[0049] S1, 90 mg Ce(CH 3 COO 3 ·xH 2 O was dissolved in 5 mL of triethylene glycol to form a first solution.
[0050] S2 300 mg Cu(CH 3 COO 2 Dissolve in 10 mL of triethylene glycol to form a second solution.
[0051] S3, in a 250mL three-necked flask, 200mg PVP K30 powder was dissolved in 50mL TEG and stirred at room temperature. Then, the solution was heated to 200°C, the first solution was rapidly added dropwise, and stirring was maintained. Next, when the system temperature reached 260°C, the second solution was rapidly injected under strong magnetic stirring. After maintaining at this temperature for 10 minutes, the entire reactor was rapidly cooled. The obtained purple solution was washed and centrifuged (8000rpm, 5 minutes) with acetone and ethanol for several times to obtain a purple-black precipitate. The precipitate was dried at 60°C for 12 hours in a vacuum drying oven to obtain a dry copper-cerium nanoparticle sample.
[0052] Furthermore, a variety of characterization techniques were used to analyze the structure of the prepared copper-cerium nanoparticle samples, and the morphology and particle size distribution of the catalyst were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Figure 2 and Figure 3 As shown in the SEM image, it can be seen that the addition of cerium changes the dispersion state of the particles. In the TEM image, regions with lattice spacings of 208.93, 234.55, and 313.25 can be observed, corresponding to the Cu{1 1 1} crystal plane, Ce{1 1 1} crystal plane, and Cu{1 1 1} crystal plane. 2 O 3 {3 3 2} crystal plane, CeO 2 {1 1 1} crystal plane, proving the presence of trivalent cerium in the doped nanoparticles.
[0053] Furthermore, X-ray diffraction (XRD) was used to study the crystal structure of the catalyst, such as Figure 4 As shown, it can be seen that the cerium element exists mostly in an amorphous form.
[0054] Furthermore, the linear sweep voltammetry was used to test the performance of the CuCe nanoparticle catalyst in CO 2 +N 2 Catalytic performance in saturated electrolyte: The catalyst was coated on a glassy carbon electrode as the working electrode, the reference electrode was a saturated calomel electrode (SCE), and the counter electrode was a platinum electrode. The LSV test was performed on an electrochemical workstation with a scan rate of 50 mV / s and a potential range of -7.0 V to 0 V (vs. RHE). Figures 5 to 7 As shown in the figure, by comparing the starting potential, peak current and overpotential of different catalysts, it is evaluated that the catalytic activity is higher. 2 With N 2 Under normal conditions, the copper-cerium nanoparticle catalyst has a lower starting potential and a higher peak current than copper nanoparticles and carbon paper as a blank control.
[0055] Furthermore, the catalytic reaction was carried out under constant potential, and the current versus time curve (It curve) was recorded to evaluate the stability and durability of the catalyst, such as Figure 8 As shown, the catalyst was coated on carbon cloth as the working electrode. 2 +N 2 Constant potential electrolysis was carried out in a saturated electrolyte with the potential set to -4.5 V (vs. RHE). The current changes during the electrolysis process were recorded, and the selectivity of the catalyst for urea synthesis was evaluated by calculating the Faraday efficiency.
[0056] Furthermore, the urea yield and Faradaic efficiency of the CuCe nanoparticle catalyst are shown in Figure 2. Fig. 9 By quantitatively analyzing the urea content in the electrolysis product, the urea yield was calculated to be 12.02 mmol h -1 g -1 At the same time, according to the amount of electricity consumed in the electrolysis process and the theoretical amount of urea produced, the Faraday efficiency was calculated to be 30.30%. It can be seen that the copper-cerium nanoparticle catalyst has a higher urea yield and Faraday efficiency.
[0057] Furthermore, the catalytic performance of the copper-cerium nanoparticle catalyst was tested at different working voltages. By changing the potential setting during the electrolysis process, the effect of the working voltage on the urea yield and Faraday efficiency was studied. By comparing the test results at different voltages, the working voltage conditions were optimized to improve the catalytic performance and product selectivity. Fig.10 As shown in the figure, the results show that as the working voltage decreases, the urea yield first increases and then decreases, while the Faraday efficiency gradually increases with the decrease in voltage. By comparing the test results at different voltages, the optimal working voltage condition is determined to be -4.5V (vs. RHE). Under this condition, the copper-cerium nanoparticle catalyst exhibits higher urea yield and Faraday efficiency.
[0058] Comparative Example 1
[0059] This example provides a method for preparing a copper nanoparticle catalyst, comprising the following steps:
[0060] S1. 300 mg of Cu(CH 3 COO 2 Dissolve in 10 mL of triethylene glycol (TEG) to form a copper precursor solution.
[0061] S2, in a 250mL three-necked flask, 200mg PVP K30 powder was dissolved in 50mL TEG and stirred evenly at room temperature. Then, the solution was heated to 260°C, and the copper precursor solution was quickly injected into the flask under strong magnetic stirring. After maintaining at this temperature for 10 minutes, the entire reactor was quickly cooled. The obtained purple solution was washed and centrifuged (8000rpm, 5 minutes) with acetone and ethanol for several times to obtain a purple-black precipitate. The precipitate was dried at 60°C for 12 hours in a vacuum drying oven to obtain a dry copper nanoparticle sample.
[0062] Furthermore, a variety of characterization techniques were used to analyze the structure of the prepared copper nanoparticle samples, and the morphology of the catalyst was observed by scanning electron microscopy (SEM). Fig.11 As shown, it can be seen from the SEM image that the sample presents a uniform granular shape.
[0063] Furthermore, X-ray diffraction (XRD) was used to study the crystal structure of the catalyst, such as Figure 4 As shown, the main peaks are the characteristic peaks of copper and its oxides.
[0064] Furthermore, linear sweep voltammetry was used to test the performance of the copper nanoparticle catalyst in CO 2 +N 2 Catalytic performance in saturated electrolyte: The catalyst was coated on a glassy carbon electrode as the working electrode, the reference electrode was a saturated calomel electrode (SCE), and the counter electrode was a platinum electrode. The LSV test was performed on an electrochemical workstation with a scan rate of 50 mV / s and a potential range of -7.0 V to 0 V (vs. RHE). Figure 6 As shown, the reaction activity of copper nanoparticles in this system is lower than that of copper cerium nanoparticles.
[0065] Furthermore, under the same test conditions as in Example 1, the urea yield and Faraday efficiency of the copper nanoparticle catalyst are as follows: Fig. 9 By quantitatively analyzing the urea content in the electrolysis product, the urea yield was calculated to be 2.86 mmol h -1 g -1 At the same time, according to the amount of electricity consumed in the electrolysis process and the theoretical amount of urea produced, the Faradaic efficiency was calculated to be 6.80%. It can be seen that the urea yield and Faradaic efficiency of the copper nanoparticle catalyst are relatively low.
[0066] In summary, by systematically characterizing Example 1 and Comparative Example 1 to obtain the structural characteristics of different catalysts, evaluating the catalytic performance and comparing the performance differences between different catalysts, a scientific basis is provided for optimizing catalyst design, improving reaction efficiency and product selectivity. The experimental results show that the copper-cerium nanoparticle catalyst synthesized in Example 1 exhibits more excellent catalytic performance in electrocatalytic reduction of carbon dioxide to synthesize urea. This is attributed to the formation of oxygen vacancies in the copper-cerium nanoparticles and their positive effect on the catalytic performance. Therefore, the method of this Example 1 not only provides a new idea and method for comparing catalyst performance, but also provides new inspiration and reference for research and development in the field of electrocatalytic reduction of carbon dioxide to synthesize urea.
[0067] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present disclosure, but the present disclosure is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and substance of the present disclosure, and these modifications and improvements are also considered to be within the scope of protection of the present disclosure.
Claims
1. A method for preparing a copper-cerium nanoparticle catalyst for electrocatalytic reduction of carbon dioxide and nitrogen to synthesize urea, characterized in that: The preparation method comprises: Dissolving Ce(CH3COO)3·xH2O in triethylene glycol to form a first solution; Dissolving Cu(CH3COO)2 in triethylene glycol to form a second solution; Polyvinyl pyrrolidone is dissolved in triethylene glycol, and the mixture is heated to a first temperature after stirring at room temperature, and the first solution is added. When the mixture is stirred and heated to a second temperature, the second solution is added. The stirred and cooled solution is washed, centrifuged, and dried to obtain a copper-cerium nanoparticle catalyst.
2. The preparation method according to claim 1, characterized in that: When Ce(CH3COO)3·xH2O is dissolved in triethylene glycol, the content of Ce(CH3COO)3·xH2O is 90-100 parts by mass, and the content of triethylene glycol is 5-10 parts by volume.
3. The preparation method according to claim 1, characterized in that: When Cu(CH3COO)2 is dissolved in triethylene glycol, the content of Cu(CH3COO)2 is 300-400 parts by mass, and the content of triethylene glycol is 5-10 parts by volume.
4. The preparation method according to claim 1, characterized in that: When polyvinyl pyrrolidone is dissolved in triethylene glycol, the content of the polyvinyl pyrrolidone is 200-300 parts by mass, and the content of the triethylene glycol is 50-100 parts by volume.
5. The preparation method according to claim 1, characterized in that: The first temperature is 170-210°C.
6. The preparation method according to claim 1, characterized in that: The stirring time after adding the second solution is 10-20 minutes.
7. The preparation method according to claim 1, characterized in that: The second temperature is 240° C. or higher.
8. The preparation method according to claim 1, characterized in that: The drying time is 10-14 hours.
9. A copper-cerium nanoparticle catalyst, characterized in that: The copper-cerium nanoparticle catalyst is prepared by the preparation method described in any one of claims 1 to 8.
10. A copper-cerium nanoparticle catalyst, characterized in that: The copper-cerium nanoparticle catalyst described in claim 9 is used in the electrocatalytic reduction of carbon dioxide and nitrogen to synthesize urea.