A copper-doped cerium-based catalyst, a preparation method and application thereof
The preparation of copper-doped cerium-based catalysts in a fixed-bed reactor via spray pyrolysis solves the problems of high cost of precious metal catalysts and long processing time of traditional methods, and achieves rapid preparation of efficient CO oxidation reaction and high catalyst activity.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- INNER MONGOLIA UNIV OF SCI & TECH
- Filing Date
- 2026-05-25
- Publication Date
- 2026-06-30
AI Technical Summary
Existing precious metal catalysts for CO oxidation have problems such as high cost, limited resources and easy sintering. Traditional methods for preparing copper-based catalysts are time-consuming and complex, making it difficult to meet the requirements of efficient CO oxidation.
A copper-doped cerium-based catalyst was prepared in a fixed-bed reactor using a spray pyrolysis method. The amount of Cu doping was controlled to form a spherical porous structure, with copper highly dispersed on the surface of the cerium dioxide support, thus avoiding the calcination process. The catalyst structure and specific surface area were characterized by XRD, SEM, and BET.
This method enables the rapid preparation of highly efficient CO oxidation catalysts, reducing preparation time, avoiding porous structure collapse and specific surface area reduction, and improving catalyst activity and stability.
Smart Images
Figure CN122298440A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of rare earth catalytic materials technology, specifically relating to a copper-doped cerium-based catalyst, its preparation method, and its application. Background Technology
[0002] With increasingly stringent environmental protection regulations and the growing demand for carbon monoxide (CO) treatment in industrial flue gas, the development of highly active CO oxidation catalysts is of great significance. Catalytic oxidation is one of the most economical and efficient CO emission control technologies. CO catalysts can be divided into noble metal catalysts and non-noble metal catalysts. Although noble metal catalysts (such as Pd, Pt, and Au) have excellent catalytic performance, their high cost, limited resources, and problems such as easy sintering, carbon deposition, and poisoning limit their widespread application. Therefore, the development of non-noble metal composite oxide catalysts has become a research hotspot.
[0003] Copper-based catalysts exhibit excellent activity comparable to that of noble metals in the CO oxidation reaction. Meanwhile, cerium is abundant and inexpensive. Furthermore, CeO2 has a strong ability to transform between trivalent and tetravalent cerium ions, resulting in good absorption and release of oxygen. It also has strong interactions with metal sites, and the introduction of other metals can form more oxygen vacancies, thereby improving the redox capacity.
[0004] The synthesis of Cuo-CeO2 composite oxides often employs methods such as co-precipitation, hydrothermal synthesis, and sol-gel. In recent years, spray pyrolysis has been widely used in the field of functional materials due to the characteristics of small particle size, large specific surface area, and uniform component distribution. Direct synthesis of composite oxides through spray pyrolysis of metal chlorides can solve the problems of complex processes, long time, and large wastewater volume in traditional methods. Summary of the Invention
[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a copper-doped cerium-based catalyst, its preparation method and application. The reactor used is a fixed-bed reactor, and the amount of Cu doping is controlled to overcome the problems of long production time in traditional methods.
[0006] To achieve the above objectives, the present invention provides the following technical solution: A copper-doped cerium-based catalyst, wherein the molar ratio of copper to cerium is 0.1 to 0.3:1, the catalyst has a spherical porous structure, and copper is highly dispersed on the surface of the cerium dioxide support.
[0007] Preferably, a method for preparing a copper-doped cerium-based catalyst includes the following steps: S1: Mix cerium chloride, copper chloride, and deionized water, and stir until completely dissolved to obtain a precursor solution. The mass ratio of cerium chloride to deionized water is fixed at 1:4. The molar ratio of cerium chloride to copper chloride used is n(Ce):n(Cu) = 1:0.1; 1:0.2; 1:0.3. Stir until no more bubbles are generated and there is no solid residue, and the cerium chloride and copper chloride are basically completely dissolved in water. S2: The prepared precursor solution is atomized into atomized droplets through a nozzle using air or oxygen as a carrier at a pressure of 0.3 MPa. The atomized droplets are sprayed from the bottom or top of the pyrolysis furnace. The pyrolysis temperature is 850℃ and the pyrolysis time is 0.1 to 20 seconds. S3: The pyrolysis products are separated into powdered copper-doped cerium-based catalysts by gas-solid separation. The gas-solid separation is carried out by a cyclone separator, and the generated Cl gas is recovered into hydrochloric acid by the tail gas absorption tower.
[0008] Preferably, the chemical reaction equation for the preparation method of the above-mentioned copper-cerium composite oxide is expressed as follows: CeCl3 + H2O → CeOCl + HCl (g) (1) CeCl3+H2O → Ce2O3 + HCl (g) (2) CeCl3 +H2O + O2 → CeO2 + HCl (g) (3) CeOCl + H2O + O2 → CeO2 + HCl (g) (4) CuCl2 + H2O → CuO + HCl (g) (5) Cu2OCl2 + H2O → CuO + HCl (g) (6) CuCl2 → CuCl + Cl2 (g) (7) CuCl + H2O → Cu2O + HCl (g) (8) Cu₂O + O₂ → CuO (9) CeCl3+ H2O → Ce(OH)3 + HCl (g) (10) Ce(OH)3→ Ce2O3 + H2O (g) (11) Ce(OH)3+O2→ CeO2 + H2O (g) (12) CuCl2+ H2O → Cu2(OH)3Cl + HCl (g) (13) Cu2(OH)3Cl → CuO + HCl (g) + H2O (g) (14) CeCl3+CuCl2+H2O+O2→CeO2+CuO+HCl (g) (15) 1-xCeCl3+xCuCl2+H2O+O2→Ce1-xCuxO+HCl (g). (16) Preferably, the present invention also performs a series of characterization tests on the prepared catalyst, and uses X-ray diffraction energy dispersive spectroscopy (XRD), scanning electron microscopy (SEM) and specific surface area analysis (BET) to characterize the structure and specific surface area of the catalyst.
[0009] Preferably, the present invention also provides an application of the catalyst prepared by the method described above or the catalyst prepared by the method described above in the field of CO catalysis.
[0010] Preferably, the catalytic CO oxidation reaction was studied using a continuous flow fixed-bed reactor under atmospheric pressure. The catalyst dosage was 0.5 g, packed in the middle of a quartz tubular reactor. The feed gas was 2% CO + 10% O2 + N2, and the flow rate was 200 ml / min. The gaseous products at the reactor outlet were analyzed by gas chromatography (GC). 9160) Online analysis.
[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: By using a fixed-bed reactor and controlling the Cu doping amount, catalytic products can be obtained quickly, significantly reducing the time required. Furthermore, the traditional calcination process is skipped, avoiding the collapse of the porous structure and the reduction of specific surface area caused by calcination. Attached Figure Description
[0012] Figure 1 The XRD patterns are of Embodiments 1, 2, 3 and Comparative Example 1 of the present invention; Figure 2 These are SEM images of Embodiments 1, 2, 3 and Comparative Example 1 of the present invention; Figure 3 EDS diagrams of Embodiments 1, 2, 3 and Comparative Example 1 of the present invention; Figure 4 This is a comparison chart of the catalytic performance of different catalyst samples of the present invention. Detailed Implementation
[0013] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0014] The following embodiments are used to illustrate the present invention, but should not be used to limit the scope of protection of the present invention. The conditions in the embodiments can be further adjusted according to specific conditions, and simple improvements to the method of the present invention under the premise of the concept of the present invention are all within the scope of protection claimed by the present invention.
[0015] A copper-doped cerium-based catalyst, wherein the molar ratio of copper to cerium is 0.1 to 0.3:1, the catalyst has a spherical porous structure, and copper is highly dispersed on the surface of the cerium dioxide support.
[0016] Example 1: A method for preparing a copper-cerium composite oxide comprises the following steps: S1: Mix copper and cerium chlorides in a stoichiometric ratio of Cu:Ce = 0.1:1, and add deionized water to obtain a 20wt% chloride mixed solution raw material; S2: Using air as a carrier gas with a pressure of 0.3 MPa, the chloride mixture solution is atomized into droplets through a nozzle. The droplets are injected from the bottom or top of the pyrolysis furnace. The pyrolysis temperature is 850℃ and the pyrolysis time is 20s. After pyrolysis, a separator is used for gas-solid separation. The generated gas is recovered into hydrochloric acid through tail gas absorption, and a mixture solid is obtained and named CU-0.1.
[0017] Example 2: A method for preparing a copper-cerium composite oxide comprises the following steps: S1: Mix copper and cerium chlorides in a stoichiometric ratio of Cu:Ce = 0.2:1, and add deionized water to obtain a 20wt% chloride mixed solution raw material; S2: Referring to Example 1, a Cu:Ce=0.2:1 solution was sprayed into the furnace to obtain a mixed solid, which was named CU-0.2.
[0018] Example 3 S1: Mix copper and cerium chlorides in a stoichiometric ratio of Cu:Ce = 0.3:1, and add deionized water to obtain... Raw materials for a 20wt% chloride mixed solution; S2: Referring to Example 1, a Cu:Ce=0.3:1 solution was sprayed into the furnace to obtain a mixed solid, which was named CU-0.3.
[0019] Example 4 S1: Take a quantitative amount of the copper-cerium composite catalyst prepared in Example 1 and load it into a fixed-bed reaction tube. Purge with nitrogen and then purge with air. Repeat this process three times to remove all the air from the device. S2: After pressure testing and leak detection, CO at 4 ml / min, O2 at 20 ml / min, and N2 at 176 ml / min are introduced at 400℃ for 1 hour, and the CO conversion rate is observed. S3: The CO conversion rate of the copper-cerium composite catalyst prepared in Example 2 was observed according to the method in Example 4; S4: The CO conversion rate of the copper-cerium composite catalyst prepared in Example 3 was observed according to the method in Example 4.
[0020] Comparative Example 1 This comparative example provides a cerium oxide and its preparation method. Compared with Example 1, CuCl2 is not added to the precursor solution, and other conditions are the same. A mixed solid is obtained and named CE.
[0021] This application provides a series of structural and compositional characterizations of the catalysts obtained in the examples and comparative examples, from... Figure 1 The XRD patterns of CE and samples with different loadings of CU-0.1, CU-0.2 and CU-0.3 can be seen from the figure. As can be seen from the figure, each sample has obvious diffraction peaks at 2θ of about 28.5°, 33.1°, 47.5° and 56.3°, which correspond to the (111), (200), (220) and (311) crystal planes of the CeO2 fluorite cubic crystal phase, respectively, indicating that the main crystal phase of the sample is CeO2. Compared with CE, the characteristic peak positions of the loaded sample remained basically consistent, without significant shift, and no new impurity phase diffraction peaks were generated. This indicates that the basic crystal structure of CeO2 was maintained after the introduction of the loading component, and Cu mainly existed in a highly dispersed state on the support surface. The copper-doped cerium-based catalysts and pure cerium oxide obtained in Examples 1, 2, 3 and Comparative Example 1 were further characterized by SEM and EDS. The catalyst morphology was a spherical porous structure. The EDS energy spectrum confirmed that Cu was successfully doped in the copper-doped cerium-based catalyst, indicating that Ce, O and Cu were uniformly distributed. The Cl element content of the catalysts after different proportions of copper doping was determined, and the results are shown in Table 1. Compared with Comparative Example 1, the catalysts obtained in Examples 1, 2 and 3 had Cl- content of 3.1%, 6.5% and 7.1%, respectively. This indicates that copper doping (using CuCl2 as the copper source) increases the Cl- accumulation on the catalyst surface, and the Cl- content increases with the increase of Cu proportion.
[0022] Table 1:
[0023] In addition, the catalytic performance of the catalysts obtained in the embodiments and comparative examples of this application in CO oxidation was tested. The test atmosphere was 2% CO + 10% O2 by volume, with the remainder being N2.
[0024] Test results are as follows Figure 4 As shown, Cu-0.1, Cu-0.2, and Cu-0.3 can almost completely oxidize carbon monoxide at 400℃, with slight differences in time (13 min, 20 min, and 25 min respectively). In contrast, pure cerium oxide in Comparative Example 1 has a catalytic efficiency of less than 30% at 400℃. Copper doping significantly improves the catalytic efficiency. Furthermore, Table 1 shows that the proportion of Cl- also affects the catalytic rate. This is because the high activity of the copper-cerium catalyst mainly originates from the Cu+-Ov-Ce interface. 3 +Active structure, while residual chlorine weakens Cu–Ce synergy and interferes with oxygen vacancy-related sites on the cerium surface, and may even form chloride species such as CeOCl, thereby inhibiting oxygen migration and reaction cycle.
[0025] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.
[0026] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention.
Claims
1. A copper-doped cerium-based catalyst, characterized in that, The molar ratio of copper to cerium is 0.1-0.3:1, the catalyst has a porous spherical structure, and the copper element is highly dispersed on the surface of the ceria carrier.
2. A process for the preparation of a copper-doped cerium-based catalyst as claimed in claim 1, characterized in that, The one-step synthesis by the spray pyrolysis method does not need subsequent calcination and comprises the following steps: S1, mixing cerium chloride, copper chloride and deionized water, stirring until completely dissolved to obtain a precursor solution; S2, using the precursor solution as raw material and air or oxygen as carrier gas, forming droplets by atomization and then spraying into a pyrolysis furnace for pyrolysis reaction; S3, gas-solid separation of the pyrolysis product to obtain a powder-shaped copper-doped cerium-based catalyst.
3. The production method according to claim 2, characterized by, In step S1, the mass ratio of cerium chloride to deionized water is 1:4, and the concentration of the precursor solution is 20wt%.
4. The production method according to claim 2, characterized by, In step S2, the carrier gas pressure is 0.3MPa, the pyrolysis temperature is 850℃, and the pyrolysis time is 0.1-20s.
5. The preparation method according to claim 2, characterized in that, In step S3, the gas-solid separation uses a cyclone separator, and the Cl gas generated by separation is dissolved in water in a tail gas absorption tower to recover hydrochloric acid.
6. The application of the copper-doped cerium-based catalyst of claim 1 or the copper-doped cerium-based catalyst prepared by the preparation method of any one of claims 2-5 in the field of catalytic oxidation of carbon monoxide.
7. Use according to claim 6, characterized in that, The catalytic reaction conditions are: 400℃, the raw material gas composition is 2% CO+10% O2+N2, and complete oxidation of carbon monoxide can be achieved.