Cerium oxide-aluminum oxide composite material as well as preparation method and application thereof
By preparing cerium oxide-alumina composite material as a catalyst, the problem of poor purification effect of existing catalysts on nitrogen oxides and chlorine-containing volatile organic compounds in incineration waste gas was solved, and a high-efficiency purification effect was achieved within the matched temperature window.
Patent Information
- Application Number
- CN202511999490.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-29
- Publication Date
- 2026-02-13
AI Technical Summary
Existing catalysts are unable to effectively remove nitrogen oxides (NOx) and chlorinated volatile organic compounds (CVOCs) simultaneously from incineration exhaust gases due to mismatched reaction temperature windows, resulting in poor purification performance.
Using cerium oxide-aluminum oxide composite material as a catalyst, Al2O3 is prepared through co-precipitation reaction and calcination, ensuring that Al2O3 is highly dispersed on CeO2 support, providing effective active sites, and enabling the oxidation of CVOCs and the reduction of NOx to proceed within a matched temperature window.
It achieves efficient oxidation of chlorine-volatile organic compounds and high conversion rate of nitrogen oxides within a temperature range of 350~450℃, thereby improving the purification effect of the catalyst.
Smart Images
Figure CN121513841A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of catalyst technology, and in particular to a cerium oxide-alumina composite material, its preparation method, and its application. Background Technology
[0002] In recent years, with the increasing scarcity of land resources, incineration technology has gradually become the mainstream method for the disposal of hazardous waste. Incineration exhaust gas also contains nitrogen oxides (NOx). x ) and chlorinated volatile organic compounds (CVOCs) cause air pollution and seriously endanger human health. NO x The synergistic purification of CVOCs and nitrogen oxides has significant ecological and economic benefits, thus necessitating the design of a dual-effect catalyst to achieve simultaneous elimination of both. However, commonly used catalysts generally suffer from a mismatch in temperature windows between the thermocatalytic oxidation of chlorinated volatile organic compounds and the reduction of nitrogen oxides. Summary of the Invention
[0003] In view of this, the purpose of this invention is to provide a cerium oxide-alumina composite material, its preparation method, and its application. The cerium oxide-alumina composite material provided by this invention, as a catalyst, can synergistically purify NO. x With CVOCs, simultaneously targeting the oxidation of CVOCs and NO x The reduction has a matching reaction temperature window.
[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing a cerium oxide-alumina composite material, comprising the following steps: Cerium nitrate, aluminum nitrate, and water are mixed to obtain a mixed solution; the molar ratio of cerium nitrate to aluminum nitrate is 10:1. Ammonia water was added to the mixed solution to carry out a co-precipitation reaction, followed by solid-liquid separation to obtain precursor powder; The precursor powder was calcined to obtain the cerium oxide-aluminum oxide composite material.
[0005] Preferably, the calcination temperature is 500°C.
[0006] Preferably, the calcination holding time is 6 hours.
[0007] Preferably, the cerium nitrate comprises cerium nitrate hexahydrate.
[0008] Preferably, the aluminum nitrate comprises aluminum nitrate hexahydrate.
[0009] Preferably, the concentration of cerium nitrate in the mixed solution is 5 mol / L.
[0010] Preferably, the solid-liquid separation further includes drying the resulting wet solid.
[0011] The present invention provides a cerium oxide-aluminum oxide composite material prepared by the preparation method described above, comprising a CeO2 support and Al2O3 supported on the CeO2 support.
[0012] This invention provides the application of the cerium oxide-alumina composite material described above as a catalyst in the simultaneous catalytic oxidation of chlorine-containing volatile organic compounds and reduction of nitrogen oxides.
[0013] Preferably, the temperature for the catalytic oxidation of chlorine-containing volatile organic compounds and reduction of nitrogen oxides is 350~450℃.
[0014] This invention provides a method for preparing a cerium oxide-alumina composite material, comprising the following steps: mixing cerium nitrate, aluminum nitrate, and water to obtain a mixed solution; wherein the molar ratio of cerium nitrate to aluminum nitrate is 10:1; adding ammonia water to the mixed solution for a co-precipitation reaction, followed by solid-liquid separation to obtain a precursor powder; and calcining the precursor powder to obtain the cerium oxide-alumina composite material. The preparation method of this invention, through the selection of raw materials and optimization of preparation steps and process parameters, results in a catalyst with high activity. This is because the high dispersion of the active component (Al₂O₃) on the support (CeO₂) and the suitable crystal structure provide more effective active sites, promoting the adsorption and transformation of reactant molecules. The cerium oxide-alumina composite material provided by this invention, as a catalyst, can synergistically purify NO. x With CVOCs, simultaneously targeting the oxidation of CVOCs and NO x The reduction has a matching reaction temperature window. Attached Figure Description
[0015] Figure 1 The XRD pattern of the catalyst prepared in Example 1; Figure 2 The image shows the catalytic performance of the catalyst prepared in Example 1. Detailed Implementation
[0016] This invention provides a method for preparing a cerium oxide-alumina composite material, comprising the following steps: Cerium nitrate, aluminum nitrate, and water are mixed to obtain a mixed solution; the molar ratio of cerium nitrate to aluminum nitrate is 10:1. Ammonia water was added to the mixed solution to carry out a co-precipitation reaction, followed by solid-liquid separation to obtain precursor powder; The precursor powder was calcined to obtain the cerium oxide-aluminum oxide composite material.
[0017] Unless otherwise specified, all raw materials used in this invention are commercially available products well known in the art.
[0018] This invention involves mixing cerium nitrate, aluminum nitrate, and water to obtain a mixed solution.
[0019] In this invention, the cerium nitrate preferably comprises cerium nitrate hexahydrate; the aluminum nitrate comprises aluminum nitrate hexahydrate; the water is preferably deionized water; and the cerium nitrate and aluminum nitrate are preferably of analytical grade. In this invention, the mixing of cerium nitrate, aluminum nitrate, and water preferably comprises: dissolving cerium nitrate in a portion of the water to obtain a cerium nitrate solution; dissolving aluminum nitrate in the remaining water to obtain an aluminum nitrate solution; and mixing the cerium nitrate solution and the aluminum nitrate solution.
[0020] In this invention, the concentration of cerium nitrate in the mixed solution is 5 mol / L; the molar ratio of cerium nitrate to aluminum nitrate is 10:1.
[0021] After obtaining the mixed solution, the present invention adds ammonia water to the mixed solution to carry out a co-precipitation reaction, and separates the solid and liquid to obtain the precursor powder.
[0022] This invention does not impose special limitations on the concentration and amount of ammonia water, as long as the co-precipitation reaction is complete. Preferably, ammonia water is added under stirring conditions; after the ammonia water is completely added, stirring is preferably continued for 3 hours to complete the co-precipitation reaction.
[0023] The present invention does not have any special requirements for the solid-liquid separation method; any solid-liquid separation method well known in the art can be used, such as centrifugation.
[0024] After completing the solid-liquid separation, the present invention preferably further includes drying the resulting wet solid. In the present invention, the drying temperature is preferably 70°C, and the drying time is preferably 12 hours.
[0025] After obtaining the precursor powder, the present invention calcines the precursor powder to obtain the cerium oxide-aluminum oxide composite material.
[0026] In this invention, the calcination temperature is preferably 500°C; the calcination holding time is preferably 6 hours; and the calcination is preferably carried out in an air atmosphere.
[0027] The present invention provides a cerium oxide-aluminum oxide composite material prepared by the preparation method described above, comprising a CeO2 support and Al2O3 supported on the CeO2 support.
[0028] The present invention also provides the application of the cerium oxide-alumina composite material described above as a catalyst in the simultaneous catalytic oxidation of chlorine-containing volatile organic compounds and reduction of nitrogen oxides.
[0029] In this invention, the preferred temperature for the catalytic oxidation of chlorine-containing volatile organic compounds and reduction of nitrogen oxides is 350~450℃, and in specific embodiments it can be 350, 375, 400, 425 or 450℃.
[0030] In this invention, the space velocity for the simultaneous catalytic oxidation of chlorine-containing volatile organic compounds and reduction of nitrogen oxides is preferably 40,000 mL / (gh).
[0031] The following detailed description of the cerium oxide-alumina composite material, its preparation method, and its application provided by the present invention, with reference to specific embodiments, should not be construed as limiting the scope of protection of the present invention.
[0032] Example 1 Take 2.13g of aluminum nitrate hexahydrate (analytical grade), dissolve it in 100mL of deionized water, stir at room temperature until completely dissolved, and prepare a solution with a concentration of 1mol / L.
[0033] Take 43.42 g of cerium nitrate hexahydrate (analytical grade), dissolve it in 100 mL of deionized water, stir at room temperature until completely dissolved, and prepare a solution with a concentration of 10 mol / L.
[0034] The two precursor solutions were mixed, and ammonia was added dropwise until complete precipitation. The mixture was stirred vigorously at room temperature for 3 hours. The sample was then separated using a centrifuge and stored in a vacuum drying oven at 70°C for 12 hours to obtain the precursor powder.
[0035] The obtained precursor powder was calcined in a muffle furnace at 500°C for 6 hours to obtain the catalyst.
[0036] The prepared catalyst was characterized by XRD, and the results are shown in the figure. Figure 1 .Depend on Figure 1 It can be seen that the catalyst showed characteristic diffraction peaks of CeO2, and Al2O3 was not detected, indicating that Al2O3 was highly dispersed on the CeO2 surface and did not change the crystal structure of CeO2.
[0037] The catalyst was screened to 40-60 mesh for catalytic performance evaluation.
[0038] Performance testing The activity of the catalyst in the oxidation reaction was evaluated using chlorobenzene (CB) and nitric oxide (NO) as probe molecules in a quartz fixed-bed microreactor (6 nm inner diameter) under atmospheric pressure. The effluent gas from the reaction was detected using a Shimadzu gas chromatograph (GC-2014C), and the data were analyzed using the area normalization method. The reaction conditions were as follows: a mixed gas was introduced into the reactor, consisting of 500 ppm chlorobenzene + 500 ppm nitric oxide + 10 vol% O2 + N2 (equilibrium gas), and the space velocity was 40000 mL / (gh). The conversion rates of chlorobenzene and nitric oxide by the catalyst at different temperatures are shown in the figure. Figure 2 .
[0039] Depend on Figure 2 It can be seen that the conversion rate of chlorobenzene gradually increases with increasing reaction temperature, reaching over 60% when the temperature exceeds 350℃; and the catalyst achieves over 90% conversion of NO within the 300~450℃ range. This indicates that the catalyst prepared in this invention has a matched reaction temperature window in the thermocatalytic oxidation of chlorine-containing volatile organic compounds and the selective catalytic reduction of nitrogen oxides.
[0040] Comparative Example 1 The catalytic performance was tested using commercially available vanadium-tungsten-titanium catalysts under the same conditions as in Example 1. The results showed that the catalyst prepared in this invention has a wider reaction window compared to the vanadium-tungsten-titanium catalyst.
[0041] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A method for producing a ceria-alumina composite material, characterized by, The method comprises the following steps: mixing cerium nitrate, aluminum nitrate and water to obtain a mixed solution; the molar ratio of the cerium nitrate to the aluminum nitrate is 10:1; adding ammonia water into the mixed solution to perform a co-precipitation reaction, and performing solid-liquid separation to obtain a precursor powder; calcining the precursor powder to obtain the cerium oxide-aluminum oxide composite material.
2. The production method according to claim 1, characterized by, The calcination temperature is 500 DEG C.
3. The production method according to claim 1 or 2, characterized by, The holding time of the calcination is 6 h.
4. The method of claim 1, wherein, The cerium nitrate comprises cerium nitrate hexahydrate.
5. The preparation method according to claim 1, characterized in that, The aluminum nitrate comprises aluminum nitrate hexahydrate.
6. The method of claim 1, wherein, The concentration of the cerium nitrate in the mixed solution is 5 mol / L.
7. The preparation method according to claim 1, characterized in that, The solid-liquid separation further comprises drying the obtained wet solid. 8.The cerium oxide-aluminum oxide composite material prepared by the method of any one of claims 1-7, comprising a CeO2 carrier and Al2O3 loaded on the CeO2 carrier. 9.The application of the cerium oxide-aluminum oxide composite material of claim 8 as a catalyst in simultaneously catalyzing oxidation of chlorine-containing volatile organic compounds and reduction of nitrogen oxides.
10. Use according to claim 9, characterized in that, The temperature of the catalysis of the oxidation of chlorine-containing volatile organic compounds and the reduction of nitrogen oxides is 350-450 DEG C.