A rare earth oxide supported copper oxide material and a method for its preparation
By controlling the molar ratio of Cu+ and Cu2+ in copper oxide materials supported by rare earth element oxides, and by combining treatment with polyvinylpyrrolidone and ascorbic acid, copper oxide materials with high catalytic performance and stability were prepared, solving the problem of difficult control of the valence state of copper ions and improving catalytic performance and structural stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- WEICHAI POWER CO LTD
- Filing Date
- 2024-01-25
- Publication Date
- 2026-05-22
AI Technical Summary
In rare earth element oxide-supported copper oxide materials, the valence state of copper ions is difficult to control, resulting in insufficient catalytic performance or low catalyst stability.
By controlling the molar ratio of Cu+ to Cu2+ in copper oxide particles to 35%-50%, and treating a mixed solution of rare earth element oxides and soluble copper salts with polyvinylpyrrolidone and ascorbic acid under certain conditions, followed by sintering, copper oxide materials loaded with rare earth element oxides were prepared.
This method achieves moderate control of copper ions, improves catalytic performance and structural stability, and is particularly beneficial for selecting the reaction pathway that produces C2 products in the carbon dioxide reduction reaction, thereby improving the activity and selectivity of the catalyst.
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Figure CN117816182B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of copper oxide composite materials technology, and in particular to a copper oxide material supported by rare earth element oxides and its preparation method. Background Technology
[0002] Rare earth element oxides, such as cerium oxide, are widely used in many fields as common metal oxide supports and important components of bimetallic composite modified materials. Currently, copper oxide materials supported on rare earth element oxides still face challenges in application, including difficulty in controlling the valence state of copper ions, leading to insufficient catalytic performance or low catalyst stability. Summary of the Invention
[0003] This application discloses a copper oxide material supported by rare earth element oxides and its preparation method, in order to improve the problem that the valence state of copper ions in existing copper oxide materials supported by rare earth element oxides is difficult to control.
[0004] To achieve the above objectives, this application provides the following technical solution:
[0005] In a first aspect, this application provides a copper oxide material supported on rare earth element oxides. The copper oxide material includes a rare earth element oxide layer and copper oxide particles disposed on the surface of the rare earth element oxide layer. The copper oxide particles include Cu. 2+ and Cu + , where Cu + Molar amount of Cu 2+ and Cu 1+ The ratio of the sum of their molar amounts is 35%-50%.
[0006] Furthermore, the average particle size of the copper oxide particles is 80-120 nm.
[0007] Furthermore, copper oxide particles account for 5%-20% of the mass of the composite material.
[0008] Secondly, this application provides a method for preparing copper oxide material supported by rare earth element oxides. The preparation method includes the following steps: mixing rare earth element oxides, polyvinylpyrrolidone and soluble copper salt evenly to obtain a mixed solution; adding ascorbic acid to the mixed solution and keeping it at 50-60℃ for 3-5 hours; centrifuging, washing, drying and pulverizing to obtain a pulverized product; and sintering the pulverized product to obtain copper oxide material supported by rare earth element oxides.
[0009] Furthermore, the pH of the mixed solution is 9-10, and / or the drying temperature is 60-80℃, and the drying time is 8-15h.
[0010] Furthermore, the molar ratio of copper ions in rare earth element oxides and soluble copper salts is 1.8:1-2:1.
[0011] Furthermore, the rare earth element oxide is selected from at least one of cerium oxide, zirconium oxide, and lanthanum oxide.
[0012] Furthermore, the soluble copper salt is selected from at least one of copper nitrate, copper chloride, and copper sulfate.
[0013] Furthermore, the sintering temperature is 400-700℃ and the time is 3-6h.
[0014] Furthermore, the process of uniformly mixing rare earth element oxides, polyvinyl pyrrolidone (PVP), and soluble copper salts includes: dissolving powdered rare earth element oxides in deionized water to obtain a suspension, adding PVP to the suspension, mixing thoroughly, and then adding a soluble copper salt solution.
[0015] The beneficial effects of adopting the technical solution of this application are as follows:
[0016] The rare earth element oxide-supported copper oxide material provided in this application includes a rare earth element oxide layer and copper oxide particles disposed on the surface of the rare earth element oxide layer, wherein the copper oxide particles include Cu. 2+ and Cu + , where Cu + Molar amount of Cu 2+ and Cu + The ratio of the sum of the molar amounts is 35%-50%, which regulates Cu. + A moderate concentration helps to select a reaction pathway that produces C2 products during carbon dioxide reduction, and improves the catalytic performance and structural stability of the copper oxide material supported by the rare earth element oxide. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of the preparation process of rare earth element oxide-supported copper oxide material in one possible embodiment of this application;
[0018] Figure 2 This is a SEM image of P-CeO2 in Example 1 of this application;
[0019] Figure 3 This is a TEM image of P-CeO2 in Example 1 of this application;
[0020] Figure 4 This is a SEM image of P-Cu / CeO2 in Example 1 of this application;
[0021] Figure 5This is a TEM image of P-Cu / CeO2 in Example 1 of this application;
[0022] Figure 6 This is an HRTEM image of P-Cu / CeO2 in Example 1 of this application;
[0023] Figure 7 This is a SAED image of P-Cu / CeO2 in Example 1 of this application;
[0024] Figure 8 EDS mapping of P-Cu / CeO2 in Embodiment 1 of this application;
[0025] Figure 9 The XRD patterns are of P-CeO2, P-Cu / CeO2, and samples from Comparative Examples 2-4 in Example 1 of this application.
[0026] Figure 10 Raman spectroscopy for P-CeO2, P-Cu / CeO2, and samples from Comparative Examples 2-4 in Example 1 of this application;
[0027] Figure 11 This is a low-magnification SEM image of the sample in Comparative Example 1 of this application;
[0028] Figure 12 This is a high-magnification SEM image of the sample in Comparative Example 1 of this application;
[0029] Figure 13 This is a low-magnification SEM image of the sample in Comparative Example 2 of this application;
[0030] Figure 14 This is a high-magnification SEM image of the sample in Comparative Example 2 of this application;
[0031] Figure 15 This is a low-magnification SEM image of the sample in Comparative Example 3 of this application;
[0032] Figure 16 This is a high-magnification SEM image of the sample in Comparative Example 3 of this application;
[0033] Figure 17 This is a low-magnification SEM image of the sample in Comparative Example 4 of this application;
[0034] Figure 18 This is a high-magnification SEM image of the sample in Comparative Example 4 of this application;
[0035] Figure 19 The XPS total spectrum of the sample in Example 1 of this application;
[0036] Figure 20The Cu 2p spectrum of the sample in Example 1 of this application;
[0037] Figure 21 The Cu 2p spectrum of the sample in Comparative Example 1 of this application;
[0038] Figure 22 The Cu 2p spectrum of the sample in Comparative Example 2 of this application;
[0039] Figure 23 The Cu 2p spectrum of the sample in Comparative Example 3 of this application;
[0040] Figure 24 The Cu 2p spectrum of the sample in Comparative Example 4 of this application;
[0041] Figure 25 The LSV curves of Example 1 and Comparative Examples 1-4 in carbon dioxide-saturated 0.1M KHCO3 are shown.
[0042] Figure 26 The diagram shows the C2 Faraday efficiency of Example 1 and Comparative Examples 1-4 in this application. Detailed Implementation
[0043] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0044] The application scenarios described in this application are for the purpose of more clearly illustrating the technical solutions of this application, and do not constitute a limitation on the technical solutions provided in this application. Those skilled in the art will understand that with the emergence of new application scenarios, the technical solutions provided in this application are also applicable to similar technical problems. In the description of this application, unless otherwise stated, "multiple" means two or more.
[0045] When preparing copper oxide materials supported by rare earth element oxides, the valence state of copper ions is still difficult to control in application, resulting in insufficient catalytic performance or low catalyst stability.
[0046] In view of this, this application provides a copper oxide material supported on rare earth element oxides. The copper oxide material includes a rare earth element oxide layer and copper oxide particles disposed on the surface of the rare earth element oxide layer. The copper oxide particles include Cu. 2+ and Cu1+ , where Cu 1+ Molar amount of Cu 2+ and Cu 1+ The ratio of the sum of their molar amounts is 35%-50%.
[0047] Among them, Cu 1+ Molar amount of Cu 2+ and Cu 1+ Examples of the ratio of the sum of molar amounts are 40%, 41%, 42%, 43%, 44%, 45%, or any other value between 40% and 45%.
[0048] In some embodiments of this application, the average particle size of the copper oxide particles is 80-120 nm. Examples of the average particle size of the copper oxide particles are 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, or any other value among 80-120 nm.
[0049] In some embodiments of this application, copper oxide particles account for 5%-20% of the mass of the composite material, thereby regulating the Cu content. + The concentration of copper oxide particles is kept within a suitable range to enhance the catalytic performance of copper oxide materials supported on rare earth element oxides. Examples of the mass percentage of copper oxide particles in the composite material are 5%, 8%, 10%, 12%, 15%, 20%, or any other value between 5% and 20%.
[0050] Based on the same inventive concept, this application provides a method for preparing copper oxide material supported by rare earth element oxides. Figure 1 This is a schematic diagram of the preparation process of rare earth element oxide-supported copper oxide material in one possible embodiment of this application, with reference to... Figure 1 The preparation method includes the following steps:
[0051] 1) Mix rare earth element oxides, polyvinyl pyrrolidone (PVP) and soluble copper salt evenly to obtain a mixed solution;
[0052] 2) Add ascorbic acid to the mixed solution and keep it at 50-60℃ for 3-5 hours. After centrifugation, washing, drying and pulverizing, the pulverized product is obtained.
[0053] 3) After sintering, the pulverized product is used to obtain copper oxide material supported by rare earth element oxides.
[0054] This application does not specify the order in which rare earth element oxides, polyvinyl pyrrolidone (PVP), and soluble copper salts are added, as long as the three are mixed evenly.
[0055] Preferably, firstly, powdered rare earth element oxides are dissolved in deionized water to obtain a suspension, then PVP is added to the suspension and stirred until the suspension is evenly mixed, and then a soluble copper salt solution is added to the suspension.
[0056] Optionally, rare earth element oxides are dissolved in deionized water and then ultrasonically dispersed to obtain a suspension. The ultrasonic dispersion time is 30-60 min.
[0057] Optionally, ascorbic acid can be added to the mixed solution and heated at 50-60°C using an oil bath or water bath.
[0058] In some embodiments of this application, the rare earth element oxide is selected from at least one of cerium oxide, zirconium oxide, and lanthanum oxide.
[0059] In some embodiments of this application, the soluble copper salt is selected from at least one of copper nitrate, copper chloride, and copper sulfate.
[0060] In some embodiments of this application, the pH value of the mixed solution is 9-10. The pH value of the mixed solution is adjusted by adding a pH adjuster; specifically, the pH adjuster may be sodium carbonate solution, potassium carbonate, or sodium bicarbonate.
[0061] In some embodiments of this application, the drying temperature is 60-80°C and the drying time is 8-15 hours. This application does not limit the drying method; preferably, vacuum drying is used.
[0062] Alternatively, the method of cooling after drying is natural cooling.
[0063] In some embodiments of this application, the molar ratio of copper ions in rare earth element oxides and soluble copper salts is 1.8:1-2:1.
[0064] In some embodiments of this application, the sintering temperature is 400-700℃ and the time is 3-6h. The heating rate is preferably 5℃ / min.
[0065] In some embodiments of this application, the volume ratio of the mixed solution to ascorbic acid is 9:1 to 3.6:1.
[0066] Reference Figure 1 PVP can improve the uniformity of copper salts during precipitation, thereby providing more active sites and thus improving their catalytic activity.
[0067] Continue to refer to Figure 1Ascorbic acid, a weak reducing agent, combined with annealing and calcination, reconstructs the valence state of copper and cerium and modulates the morphology of the composite material, thereby providing more active sites and a more stable structure, achieving good catalytic stability. A suitable Cu+ concentration and uniformly dispersed active sites facilitate the selection of reaction pathways that produce C2 products during carbon dioxide reduction, making it easier to proceed towards conversion to ethylene and ethanol.
[0068] The rare earth element oxide-supported copper oxide material and its preparation method in this application will be further described in detail below with reference to specific embodiments and comparative examples.
[0069] Example 1
[0070] This embodiment describes a copper oxide material supported by rare earth element oxides and its preparation method. The preparation method of the copper oxide material supported by rare earth element oxides includes the following steps:
[0071] Step 1) Grind Ce(NO3)2·6H2O into powder, then heat it to 450℃ in statically flowing air at a heating rate of 2℃ / min and keep it at that temperature for 4h to obtain yellow solid cerium oxide. Grind the solid cerium oxide into powder and name it P-CeO2.
[0072] Step 2) Place powdered cerium oxide in a 100mL beaker, add 20mL of deionized water, and sonicate for 30min to obtain a suspension. Add 3g of PVP powder to the suspension and stir for 30min until the suspension is uniformly mixed. Then add 18mL of a pre-prepared 0.043mol / L copper nitrate solution, and adjust the pH of the solution to 9.5 with 0.5mol / L sodium carbonate solution. Stir for 1h (the solution turns light green) to obtain a mixed solution.
[0073] Step 3) Add 5 mL of 4 mol / L ascorbic acid solution to the mixed solution, incubate in a water bath at 55°C for 3 h, centrifuge the resulting solution, wash the precipitate three times each with deionized water and ethanol, vacuum dry at 60°C for 10 h, and grind it into powder to obtain the pulverized product.
[0074] Step 4) Calcine the pulverized product at 500℃ for 3 hours with a heating rate of 5℃ / min. After cooling, cerium oxide-supported copper oxide material is obtained and named P-Cu / CeO2.
[0075] Examples 2-9 and Comparative Examples 1-6
[0076] Examples 2-9 and Comparative Examples 1-6 are all copper oxide materials supported by rare earth element oxides and their preparation methods. The specific steps can be referred to in Example 1. The difference is the difference in experimental conditions, which can be found in Table 1. PVP was not added in Comparative Example 2.
[0077] The performance of the rare earth element oxide-supported copper oxide materials in Examples 1-9 and Comparative Examples 1-6 was tested. The test items and test methods are as follows:
[0078] Electrochemical catalytic carbon dioxide reduction testing requires an electrolytic cell, an electrochemical workstation, a computer, and gas chromatography and liquid chromatography for product detection. Gas phase product detection can be performed real-time using online equipment. For liquid phase products, a certain coulombic concentration needs to be accumulated in the electrolyte to reach the detection limit of the liquid chromatography before sampling and detection in the liquid chromatograph. An H-type electrolytic cell is used. The operating potential during the test can be converted using the following formula: E(vs.RHE)=(0.0592×pH)+E Ag / AgCl +E(vs.Ag / AgCl).
[0079] Preparation process of catalyst ink and working electrode: Weigh 5 mg of sample (the product in the examples or comparative examples of this application), dissolve the sample in 200 μL of isopropanol in a small centrifuge tube, then add 5 μL of 5% Nafion, and sonicate for 30 min to obtain uniform ink. Take 40 μL of uniform ink and drop it onto a cleaned glassy carbon electrode, let it air dry naturally to obtain the working electrode.
[0080] The catalyst was subjected to IT tests at different voltages. After qualitative and quantitative analysis of the gaseous products using chromatography, the Faradaic efficiency of each gaseous product was calculated using the following formula:
[0081]
[0082] Note: p is the concentration of the product, i is the current, α is the number of electrons transferred in the product, and v is the flow rate of CO2.
[0083] The formula for calculating the Faraday efficiency of liquid-phase products is as follows:
[0084] Note: e is the number of electrons transferred, n is the amount of substance of the liquid product, and Q is the total amount of electricity generated during electrolysis.
[0085] Table 1
[0086]
[0087] Referring to the data in Table 1, the copper oxide materials supported on rare earth element oxides prepared in this embodiment all exhibit high catalytic performance.
[0088] Figure 2 This is a SEM image of P-CeO2 in Embodiment 1 of this application. Figure 3This is a TEM image of P-CeO2 in Embodiment 1 of this application, with reference to... Figure 2 and Figure 3 Cerium oxide has a dispersed block structure with a large planar structure, mainly exposing the cerium oxide (111) crystal plane.
[0089] Figure 4 This is a SEM image of P-Cu / CeO2 in Example 1 of this application. Figure 5 This is a TEM image of P-Cu / CeO2 in Example 1 of this application, with reference to... Figure 4 and Figure 5 The surface of the blocky cerium oxide is covered with uniformly dispersed and spherical copper oxide particles of uniform size. The surface of the spherical particles is rough and there is no obvious aggregation.
[0090] Figure 6 Here is the HRTEM image of P-Cu / CeO2 in Example 1 of this application, with reference to... Figure 6 The lattice fringes are 0.31 and 0.28 nm, respectively, corresponding to the (111) plane of cerium oxide and the (110) plane of copper oxide; Figure 7 The SAED diagram of P-Cu / CeO2 in Example 1 of this application is shown below. Figure 7 Diffraction rings corresponding to the (111) plane of cerium oxide and the (110) plane of copper oxide can be seen, indicating that the copper oxide material supported by rare earth element oxides was successfully prepared. Figure 8 This is the EDS mapping of P-Cu / CeO2 in Embodiment 1 of this application, wherein, Figure 8 A is a distribution diagram of all constituent elements of P-Cu / CeO2. Figure 8 In .B, purple represents cerium. Figure 8 .C is yellow, representing oxygen. Figure 8 .D is green, representing the element copper. (Refer to...) Figure 8 As can be seen, the surface of the bulk cerium oxide self-assembles to form rough copper oxide nanospheres with a size of about 100 nm.
[0091] Figure 9 The XRD patterns of P-CeO2, P-Cu / CeO2, and samples from Comparative Examples 2-4 in Example 1 of this application are shown below. Figure 9 The P-Cu / CeO2 and Comparative Example 3 and Comparative Example 4 samples still accurately correspond to the characteristic peaks of the cerium oxide standard spectrum, and no obvious peak position shift was found. Among them, the P-Cu / CeO2 and Comparative Example 3 samples found obvious copper oxide characteristic peaks, which correspond to the (002) and (111) planes of copper oxide, respectively. This fully demonstrates that the addition or absence of surfactants and ascorbic acid during the composite process has no significant impact on the main composition of the composite material.
[0092] The peaks at 36.5° and 42.4° of the sample in Comparative Example 4 correspond to the (111) and (200) planes of cuprous oxide, and no obvious characteristic peaks of copper oxide were found. This indicates that ascorbic acid is sufficient to dissolve Cu during the composite process. 2+ Completely reduced to Cu + Annealing and calcination are key steps in valence state reconstruction. X-ray diffraction analysis of the sample in Comparative Example 2 shows that copper oxide crystals were successfully prepared.
[0093] Figure 10 The Raman spectroscopy plots for P-CeO2, P-Cu / CeO2, and samples from Comparative Examples 2-4 in the embodiments of this application are shown below. Figure 10 The samples from Comparative Examples 2-4 and Example 1 were measured at 260.1 cm. -1 457.9cm -1 605.4cm -1 The peaks appearing at 289.7 cm⁻¹ are respectively related to the F₂g vibrational mode, the second-order transverse acoustic (2TA) mode, and the defect (D) mode of the cubic fluorite structure of cerium oxide. -1 and 613.0cm -1 The peaks appearing at [location] are attributed to the single Ag mode and two Bg light modes of copper oxide, respectively. Specifically, the peak at 219.0 cm⁻¹ is observed in the sample of Comparative Example 4. -1 and 627.5cm -1 Two distinct peaks were observed at this point, which is typical of Cu. + Raman fingerprinting further confirms that ascorbic acid can convert Cu... 2+ All converted to Cu + .
[0094] Figure 11 This is a low-magnification SEM image of the sample in Comparative Example 1 of this application. Figure 12 This is a high-magnification SEM image of the sample in Comparative Example 1 of this application, with reference to... Figure 11 and Figure 12 The sample in Comparative Example 1 consists of interlaced, near-nanoscale particles with a size between 80 and 120 nm. Figure 13 This is a low-magnification SEM image of the sample in Comparative Example 2 of this application. Figure 14 Here is a high-magnification SEM image of the sample in Comparative Example 2 of this application, with reference to... Figure 13 and Figure 14 In Comparative Example 2, where no PVP was added, significant aggregation of the formed copper oxide particles was observed. Figure 15 This is a low-magnification SEM image of the sample in Comparative Example 3 of this application. Figure 16 Here is a high-magnification SEM image of the sample in Comparative Example 3 of this application, with reference to... Figure 15 and Figure 16In Comparative Example 3, without the addition of ascorbic acid, blocky cerium oxide and spherical copper oxide particles distributed on it can be clearly seen, with the size of the spherical particles being about 1 μm. Figure 17 This is a low-magnification SEM image of the sample in Comparative Example 4 of this application. Figure 18 Here is a high-magnification SEM image of the sample in Comparative Example 4 of this application, with reference to... Figure 17 and Figure 18 The morphology of the sample in Comparative Example 4 was almost identical to that of the sample in Example 1. In summary, this demonstrates that copper oxide itself lacks the ability to form spherical structures during the synthesis of copper oxide materials, while the presence of cerium oxide facilitates the self-assembly of copper oxide into spherical structures. Even if self-assembly at the nanoscale is not achieved, it fully illustrates the synergistic effect between cerium oxide and copper oxide. The addition of ascorbic acid as a reducing agent further strengthens the interfacial effect between copper oxide and cerium oxide, promoting the self-assembly of copper oxide into three-dimensional nanospheres during the reduction process. PVP, as a surfactant, helps disperse the nano-copper oxide spheres and prevents particle aggregation.
[0095] Figure 19 The XPS total spectrum of the sample in Example 1 of this application is shown below. Figure 19 The characteristic peaks of Cu, Ce and O elements can be clearly observed, further proving the successful formation of P-Cu / CeO2 composite material.
[0096] Figure 20 This is the Cu 2p spectrum of the sample in Example 1 of this application. Figure 21 This is the Cu 2p spectrum of the sample in Comparative Example 1 of this application. Figure 22 The image shows the Cu 2p spectrum of the sample in Comparative Example 2 of this application. Figure 23 This is the Cu 2p spectrum of the sample in Comparative Example 3 of this application. Figure 24 The Cu 2p spectrum of the sample in Comparative Example 4 of this application is shown below. Figures 20 to 24 The binding energy (BEs) at the 2p³ / 2 peak is 934.2 eV. The peak at 932.7 eV can be attributed to Cu. + Based on the peak area ratio of copper oxidation states in the Cu 2p3 / 2 region, the relative Cu content of P-Cu / CeO2 (for ascorbic acid addition amounts of 5 mL, 10 mL, 15 mL, and 0 mL) was determined. + The percentages were 42.43%, 41.62%, 41.42%, and 39.80%, respectively, indicating that the amount of ascorbic acid regulates Cu. + The key factor in proportion.
[0097] No satellite peaks of copper oxide were found in the sample of Comparative Example 4; the peak at 932.7 eV was attributed to Cu. +This indicates that ascorbic acid has already converted Cu 2+ All converted to Cu + This is consistent with the XRD and Raman results. (Comparative Example 4, Sample Ce) 3+ The percentage is higher than that of other composite materials, indicating that the calcination and annealing process is a key step in valence state reconstruction, where electrons move from Ce... 3+ Transfer to Cu 2+ Ascorbic acid is a regulator of Cu + A crucial step in determining proportions.
[0098] Figure 25 The LSV curves of Example 1 and Comparative Examples 1-4 in carbon dioxide-saturated 0.1M KHCO3 are shown. Figure 26 The C2 Faraday efficiency diagrams for Example 1 and Comparative Examples 1-4 in this application are shown below. Figure 25 and Figure 26 Example 1 shows a higher current density, indicating higher electrocatalytic activity. (Refer to...) Figure 22 The results indicate that the P-Cu / CeO2 composite material exhibits significant catalytic activity for the electrocatalytic carbon dioxide reduction reaction (ECRR). Furthermore, the overall catalytic performance of the P-Cu / CeO2 samples at different application potentials for ECRR, with the Faradaic efficiencies of all products recorded in the figure, are shown. For all P-Cu / CeO2 samples, various reduction products of carbon dioxide, including carbon monoxide, methane, ethylene, ethanol, and formic acid, were detected by chromatography. C2 (ethylene + ethanol) was the target product. The conversion of C2 products from Cu / CeO2 was inferior to that from P-Cu / CeO2, with a maximum Faradaic efficiency of 65.91%. The sample in Comparative Example 1, without a cerium oxide support, showed a Faradaic efficiency of only around 50% for the C2 product at the optimal voltage, significantly lower than that of P-Cu / CeO2. The overall C2 selectivity of the sample in Comparative Example 4 was relatively low. The performance of the sample in Comparative Example 3 showed that the Faraday efficiency of C2 could reach more than 55% under -1.5V vs. RHE. The P-Cu / CeO2 composite material had higher selectivity for C2. Within the test voltage range, the Faraday efficiency of the C2 product was higher than that of other comparative samples, and its Faraday efficiency of C2 exceeded 70% under -1.5V vs. RHE.
[0099] Comparative characterization with control samples revealed that the presence of cerium oxide support provided the basic conditions for the self-assembly and valence state reconstruction of copper oxide. Ascorbic acid further enhanced the synergistic effect between cerium oxide and copper oxide during the synthesis process, resulting in a significant reduction in the size of the self-assembled copper oxide spheres. At the same time, the pre-added PVP made the distribution of copper oxide spherical particles more uniform, which is consistent with the original intention of our experimental design. This provides a new approach for the preparation and control of Cu-Metal bimetallic oxide composite materials by self-assembling uniformly dispersed copper oxide nanospheres on a Cu / CeO2 heterostructure.
[0100] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. A copper oxide material supported on rare earth element oxides, characterized in that, It includes a rare earth element oxide layer and copper oxide particles disposed on the surface of the rare earth element oxide layer, wherein the copper oxide particles include Cu. 2+ and Cu + , where Cu + Molar amount of Cu 2+ and Cu + The ratio of the sum of the molar amounts is 35%-50%; the rare earth element oxide is selected from cerium oxide; The preparation method of the rare earth element oxide-supported copper oxide material includes the following steps: Rare earth element oxides, polyvinylpyrrolidone, and soluble copper salts are mixed evenly to obtain a mixed solution; Add ascorbic acid to the mixed solution and keep it at 50-60℃ for 3-5 hours. After centrifugation, washing, drying and pulverizing, the pulverized product is obtained. The pulverized product is sintered to obtain the copper oxide material supported by rare earth element oxides.
2. The copper oxide material supported on rare earth element oxides according to claim 1, characterized in that, The average particle size of the copper oxide particles is 80-120 nm.
3. The copper oxide material supported on rare earth element oxides according to claim 1, characterized in that, The copper oxide particles account for 5%-20% of the mass of the composite material.
4. A method for preparing a copper oxide material supported on rare earth element oxides as described in any one of claims 1-3, characterized in that, Includes the following steps: Rare earth element oxides, polyvinylpyrrolidone, and soluble copper salts are mixed evenly to obtain a mixed solution; Add ascorbic acid to the mixed solution and keep it at 50-60℃ for 3-5 hours. After centrifugation, washing, drying and pulverizing, the pulverized product is obtained. The pulverized product is sintered to obtain the copper oxide material supported by rare earth element oxides. The rare earth element oxide is selected from cerium oxide.
5. The preparation method according to claim 4, characterized in that, The pH value of the mixed solution is 9-10, and / or the drying temperature is 60-80℃ and the time is 8-15h.
6. The preparation method according to claim 4, characterized in that, The molar ratio of the rare earth element oxide to the copper ions in the soluble copper salt is 1.8:1-2:
1.
7. The preparation method according to claim 4, characterized in that, The soluble copper salt is selected from at least one of copper nitrate, copper chloride, and copper sulfate.
8. The preparation method according to claim 4, characterized in that, The sintering process is carried out at a temperature of 400-700℃ for 3-6 hours.
9. The preparation method according to any one of claims 4-8, characterized in that, The mixture of rare earth element oxides, polyvinylpyrrolidone, and soluble copper salt includes: The powdered rare earth element oxides were dissolved in deionized water to obtain a suspension. PVP was added to the suspension, and after mixing evenly, a soluble copper salt solution was added.