Preparation method and application of alkali metal modified Pt-based CO oxidation catalyst with high SO2 poisoning resistance
By co-impregnating potassium nitrate and platinum nitrate on an Al2O3 support and calcining at high temperature, an alkali metal K-modified Pt/Al2O3 catalyst was prepared, which solved the problem of CO catalyst deactivation due to SO2 poisoning and achieved high efficiency in CO oxidation and resistance to poisoning, making it suitable for the purification of industrial flue gas and motor vehicle exhaust.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-22
- Publication Date
- 2026-03-27
AI Technical Summary
Existing CO catalytic oxidation catalysts are easily poisoned and deactivated by SO2 in actual flue gas, resulting in a decline in catalytic performance and making them difficult to effectively apply to the purification of industrial flue gas and motor vehicle exhaust.
An alkali metal K-modified Pt/Al2O3 catalyst was prepared by co-impregnating potassium nitrate solution and platinum nitrate solution onto an Al2O3 support using a wet impregnation method and then calcining at 550 °C.
The prepared catalyst has excellent CO oxidation performance and SO2 poisoning resistance, and is suitable for the purification of industrial flue gas and motor vehicle exhaust gas, making it suitable for large-scale industrial production.
Smart Images
Figure CN121732154A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of CO catalytic oxidation, and particularly relates to a preparation method of an alkali metal modified Pt-based CO oxidation catalyst with high SO2 poisoning resistance and application thereof. BACKGROUND
[0002] Carbon monoxide (CO) is an atmospheric pollutant, a product of incomplete combustion of fossil fuels such as coal, oil, and natural gas, and an indirect greenhouse gas. Among various atmospheric pollutants, the emission amount of CO is the largest, and its concentration change is closely related to the global industrialization process and greenhouse gas emission, which gradually attracts widespread attention of people on the climate effect and environmental pollution problems. It is estimated that the total amount of human emission of CO is 300-400 million tons per year, more than half of which comes from automobile exhaust. For a long time, mobile source pollutant emission has become one of the main sources of atmospheric pollution in China. In order to meet the increasingly stringent standards for automobile exhaust emission, motor vehicle exhaust control technology has become a research focus. In addition, excessive inhalation of CO by humans can cause hypoxia and even death. Therefore, CO emission reduction and treatment are of great significance.
[0003] CO catalytic oxidation technology is a high-efficiency and green method for solving excessive CO emission by converting CO into harmless CO2 through various high-performance catalysts. The core of CO catalytic oxidation technology is various high-performance catalysts. Noble metal catalysts have excellent catalytic activity and have attracted widespread attention from researchers in the field of CO catalytic oxidation, but there are still technical problems of poor poisoning resistance and stability. At present, most catalysts are in simulated ideal flue gas conditions, however, the actual flue gas conditions are more complex, and the toxic gases (SO2, H2S) accompanying CO emission can cause irreversible poisoning of the catalyst, especially in industrial flue gas and motor vehicle exhaust containing various toxic pollutants. SO2 molecules in the actual flue gas can be adsorbed on the active sites of the CO oxidation catalyst, thereby inducing the generation of metal sulfate species, and finally leading to serious poisoning and deactivation of the CO oxidation catalyst. The mechanism of SO2 leading to poisoning and deactivation of the catalyst is multifaceted, such as direct poisoning of the catalyst surface redox sites, competitive adsorption with reactants, and destruction of the catalyst structure, which can all cause poisoning and deactivation of the catalyst, making it a difficult and hot issue in the field of environmental catalysis to develop a CO oxidation catalyst with high SO2 resistance.
[0004] In order to make the CO oxidation catalyst more effectively applied to the purification of industrial flue gas and motor vehicle exhaust, the SO2 poisoning resistance of the catalyst needs to be improved. Therefore, it is urgent to develop a new catalyst with simple preparation process, excellent CO oxidation activity, and strong SO2 poisoning resistance. SUMMARY
[0005] The first technical problem to be solved by the present application is to provide a preparation method of an alkali metal modified Pt-based CO oxidation catalyst with high SO2 poisoning resistance, which has a simple preparation process and practical application prospect; the second technical problem to be solved by the present application is to provide an alkali metal modified Pt-based CO oxidation catalyst, which has excellent CO catalytic oxidation reaction performance; and the third technical problem to be solved by the present application is to provide an application of the alkali metal modified Pt-based CO oxidation catalyst in a CO oxidation reaction.
[0006] To solve the above technical problems, the technical solutions adopted by the present application are as follows:
[0007] The preparation method of the alkali metal modified Pt-based CO oxidation catalyst with high SO2 poisoning resistance comprises the following steps: co-impregnating a potassium nitrate solution and a platinum nitrate solution on an Al2O3 carrier by a preliminary wet impregnation method, and calcining to obtain a potassium modified Pt / Al2O3 catalyst.
[0008] Further, the loading amount of Pt is 1.0 wt.%.
[0009] Further, the loading amount of K is 1.0-5.0 wt.%.
[0010] Further, the loading amount of K is 3.0 wt.%.
[0011] Further, the calcination temperature is 550 ℃, the calcination time is 2 h, and the temperature rising rate is 5 ℃·min -1 .
[0012] Further, the calcination atmosphere is air or oxygen.
[0013] Further, the alkali metal modified Pt-based CO oxidation catalyst is prepared by the preparation method of the alkali metal modified Pt-based CO oxidation catalyst with high SO2 poisoning resistance.
[0014] Further, the application of the alkali metal modified Pt-based CO oxidation catalyst in a CO oxidation reaction.
[0015] Further, the catalytic conditions of the CO oxidation reaction are as follows: the particle size of the catalyst is 40-60 meshes, the composition ratio of the reaction gas is 1:5 for CO and O2, the concentration of SO2 is 10 ppm, and the mass space velocity for testing is 200000 mL·g cat -1 ·h -1 .
[0016] Further, the temperature range of the CO catalytic oxidation reaction is 100-250 ℃, and the SO2 poisoning resistance performance test temperature is 220 ℃.
[0017] Compared with the prior art, the present application has the following advantages:
[0018] (1) The alkali metal K modified Pt / Al2O3 catalyst can be obtained by the initial wet impregnation method and high temperature calcination, and the preparation method is simple and suitable for large-scale industrial production.
[0019] (2) The catalyst prepared by the present application has excellent CO oxidation performance and SO2 poisoning resistance, and solves the technical problems of CO oxidation catalyst in the actual industrial flue gas and motor vehicle exhaust purification application. BRIEF DESCRIPTION OF DRAWINGS
[0020] Figure 1 XRD result graph of Pt / Al2O3, 1K-Pt / Al2O3, 3K-Pt / Al2O3, 5K-Pt / Al2O3 and Al2O3 prepared in the present application;
[0021] Figure 2 CO-TPR result graph of Pt / Al2O3, 3K-Pt / Al2O3 and Al2O3 prepared in the present application;
[0022] Figure 3 CO oxidation activity graph of Pt / Al2O3, 1K-Pt / Al2O3, 3K-Pt / Al2O3 and 5K-Pt / Al2O3 prepared in the present application;
[0023] Figure 4 CO oxidation activity graph of Pt / Al2O3, 3K-Pt / Al2O3, 3Na-Pt / Al2O3 and 3Ca-Pt / Al2O3 catalysts prepared in the present application;
[0024] Figure 5 CO oxidation SO2 poisoning resistance performance test graph of Pt / Al2O3 and 3K-Pt / Al2O3 prepared in the present application under constant temperature condition. DETAILED DESCRIPTION
[0025] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described below in combination with specific examples. Unless otherwise specified, the technical means used in the following examples are all conventional means known to those skilled in the art. If the specific conditions are not specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are used. If the reagents or instruments used are not specified by the manufacturer, they are all conventional products that can be purchased on the market.
[0026] The water absorption rate of Al2O3 used in the following examples is 500 μL / g, so the amount of platinum nitrate solution (Pt content is 18.02%, density is 1.714 g / cm -3The amount of ) was 33 μL, and the amount of distilled water was 467 μL.
[0027] Example 1
[0028] Preparation of Pt / Al2O3 catalyst
[0029] Weigh 3 g of Al₂O₃ support into a crucible, adjust the Pt mass fraction to 1.0 wt.%, and measure 0.097 mL of platinum nitrate solution (Pt content 18.02%, density 1.714 g / cm³). -3 A 1.500 mL Pt precursor salt solution was prepared by diluting the powder. Platinum nitrate solution was added dropwise to the Al2O3 support, and the mixture was thoroughly impregnated. The powder was then dried in an oven at 120 °C for 20 min, and then calcined in a muffle furnace at 550 °C for 2 h in air, with a heating rate of 5 °C / min. -1 The resulting sample was denoted as Pt / Al2O3.
[0030] Example 2
[0031] Preparation of 1K-Pt / Al2O3 catalyst
[0032] The mass fraction of K was adjusted to 1.0 wt.%, and the specific steps are as follows: 3 g of Al2O3 was weighed into a crucible, and 0.097 mL of platinum nitrate solution (Pt content 18.02%, density 1.714 g / cm³) was measured. -3 Dilute to prepare a 1.500 mL Pt precursor salt solution. Weigh 0.078 g of potassium nitrate to prepare a 1.500 mL K precursor salt solution. First, add the platinum nitrate solution dropwise to the Al2O3 support, ensuring even impregnation. Place the powder in an oven at 120 ℃ for 12 h. Then, add the potassium nitrate solution dropwise to the powder, ensuring even impregnation. Place the powder in an oven at 120 ℃ for 20 min. Finally, place the powder in a muffle furnace and calcine at 550 ℃ for 2 h in air atmosphere, with a heating rate of 5 ℃·min. -1 The resulting sample was denoted as 1K-Pt / Al2O3.
[0033] Example 3
[0034] Preparation of 3K-Pt / Al2O3 catalyst
[0035] The mass fraction of K was adjusted to 3.0 wt.%, and the specific steps are as follows: 3 g of Al2O3 was weighed into a crucible, and 0.097 mL of platinum nitrate solution (Pt content 18.02%, density 1.714 g / cm³) was measured. -3) dilute to make a total volume of 1.500 mL of Pt precursor salt solution, take 0.234 g of potassium nitrate to make a total volume of 1.500 mL of K precursor salt solution, first dropwise add the platinum nitrate solution to the Al2O3 carrier, impregnate uniformly, put the powder into the oven at 120 ℃ and dry for 12 h, then dropwise add the potassium nitrate solution to the powder, impregnate uniformly, put the powder into the oven at 120 ℃ and dry for 20 min, then put it into a muffle furnace at 550 ℃ under air atmosphere, and calcine for 2 h with a heating rate of 5 ℃·min -1 , and the obtained sample is recorded as 3K-Pt / Al2O3.
[0036] Example 4
[0037] Preparation of 5K-Pt / Al2O3 catalyst
[0038] The mass fraction of K is regulated to be 5.0 wt.%, and the specific steps are as follows: take 3 g of Al2O3 in a crucible, take 0.097 mL of platinum nitrate solution (Pt content is 18.02%, density is 1.714 g / cm -3 ) dilute to make a total volume of 1.500 mL of Pt precursor salt solution, take 0.390 g of potassium nitrate to make a total volume of 1.500 mL of K precursor salt solution, first dropwise add the platinum nitrate solution to the Al2O3 carrier, impregnate uniformly, put the powder into the oven at 120 ℃ and dry for 12 h, then dropwise add the potassium nitrate solution to the powder, impregnate uniformly, put the powder into the oven at 120 ℃ and dry for 20 min, then put it into a muffle furnace at 550 ℃ under air atmosphere, and calcine for 2 h with a heating rate of 5 ℃·min -1 , and the obtained sample is recorded as 5K-Pt / Al2O3.
[0039] The catalysts prepared in Examples 1-4 and Al2O3 were respectively evaluated by X-ray diffraction (XRD), CO temperature programmed reduction (CO-TPR), CO catalytic oxidation and CO oxidation resistance to SO2 poisoning performance testing methods, and the test results are shown in Figures 1-4 .
[0040] Figure 1 The XRD results of Al2O3, Pt / Al2O3, 1K-Pt / Al2O3, 3K-Pt / Al2O3 and 5K-Pt / Al2O3 are shown in the figure, and the results show that all the Pt / Al2O3 catalysts exhibit Al2O3 structure, and no obvious crystal phase peak belonging to PtO2 appears, indicating that the Pt species is highly dispersed on the surface of Al2O3.
[0041] Figure 2The CO-TPR results for Al2O3, Pt / Al2O3, and 3K-Pt / Al2O3 are shown. The results indicate that alkali metal K modification promotes the existence of Pt species on the surface of Pt / Al2O3 catalysts in the form of Pt clusters with higher oxidation states, which is beneficial to O2 activation.
[0042] Comparative Example 1
[0043] The specific steps for adjusting the Na mass fraction to 3.0 wt.% are as follows: Weigh 3 g of Al2O3 into a crucible, and measure 0.097 mL of platinum nitrate solution (Pt content 18.02%, density 1.714 g / cm³). -3 Dilute to prepare a 1.500 mL Pt precursor salt solution. Weigh 0.333 g of sodium nitrate to prepare a 1.500 mL Na precursor salt solution. First, add the platinum nitrate solution dropwise to the Al2O3 support, ensuring even impregnation. Place the powder in an oven at 120 ℃ for 12 h. Then, add the sodium nitrate solution dropwise to the powder, ensuring even impregnation. Place the powder in an oven at 120 ℃ for 20 min. Finally, place the powder in a muffle furnace and calcine at 550 ℃ for 2 h in air atmosphere, with a heating rate of 5 ℃·min. -1 The resulting sample was denoted as 3Na-Pt / Al2O3.
[0044] Comparative Example 2
[0045] The specific steps for adjusting the mass fraction of Ca to 3.0 wt.% are as follows: Weigh 3 g of Al2O3 into a crucible, and measure 0.097 mL of platinum nitrate solution (Pt content 18.02%, density 1.714 g / cm³). -3 Dilute to prepare a 1.500 mL Pt precursor salt solution. Weigh 0.532 g of calcium nitrate tetrahydrate to prepare a 1.500 mL Ca precursor salt solution. First, add platinum nitrate solution dropwise to the Al2O3 support, ensuring even impregnation. Place the powder in an oven at 120 ℃ for 12 h. Then, add calcium nitrate solution dropwise to the powder, ensuring even impregnation. Place the powder in an oven at 120 ℃ for 20 min. Finally, place the powder in a muffle furnace and calcine at 550 ℃ for 2 h in air atmosphere, with a heating rate of 5 ℃·min. -1 The resulting sample was denoted as 3Ca-Pt / Al2O3.
[0046] Example 5
[0047] The Pt / Al₂O₃, 1K-Pt / Al₂O₃, 3K-Pt / Al₂O₃ and 5K-Pt / Al₂O₃ catalysts prepared above were applied to the CO oxidation reaction, and the results are as follows: Figure 3The results show that the modification of alkali metal K is beneficial to improve the CO oxidation activity of the catalyst, and 3K-Pt / Al2O3 shows the best CO catalytic oxidation performance, because the high valence state PtO x species.
[0048] The above prepared Pt / Al2O3, 3K-Pt / Al2O3, 3Na-Pt / Al2O3 and 3Ca-Pt / Al2O3 catalysts were applied to the CO oxidation reaction, and the results are shown in Figure 4 The results show that, compared with the modification of other alkali metals Na and Ca, the modification of metal K is beneficial to improve the CO oxidation activity of the catalyst. Further, the Pt / Al2O3 and 3K-Pt / Al2O3 catalysts were subjected to CO oxidation anti-SO2 poisoning test under constant temperature conditions, and the results are shown in Figure 5 It is found that the 3K-Pt / Al2O3 catalyst shows good anti-SO2 poisoning ability.
[0049] The specific reaction conditions are as follows: the CO oxidation reaction was carried out in a fixed bed continuous flow quartz reactor, and the catalyst particle size was 40-60 mesh. The composition of the reaction gas was CO and O2, and the ratio was 1:5, and the concentration of SO2 was 10 ppm (when anti-SO2 poisoning test), and the mass space velocity for testing was 20,0000 mL·g cat -1 ·h -1 . The CO catalytic oxidation reaction was carried out at a temperature of 100-250 ℃, and the anti-SO2 poisoning test was carried out at a constant temperature of 220 ℃. The products were analyzed by mass spectrometry, and the CO conversion rate was calculated by the following formula:
[0050] CO conversion (%) = {([CO] in - [CO] out ) / [CO] in} × 100%
[0051] The above only describes the preferred embodiments of the present application, and it should be noted that for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should also be considered as the protection scope of the present application.
Claims
1. A method for preparing an alkali metal-modified Pt-based CO oxidation catalyst with high resistance to SO2 poisoning, characterized in that, A potassium alkali metal modified Pt / Al2O3 catalyst can be obtained by co-impregnating potassium nitrate solution and platinum nitrate solution onto an Al2O3 support using the initial wet impregnation method and then calcining it.
2. The method for preparing the alkali metal-modified Pt-based CO oxidation catalyst with high resistance to SO2 poisoning according to claim 1, characterized in that: The loading of Pt is 1.0 wt.%.
3. The method for preparing the alkali metal-modified Pt-based CO oxidation catalyst with high resistance to SO2 poisoning according to claim 1, characterized in that: The loading of K is 1.0-5.0 wt.%.
4. The method for preparing the alkali metal-modified Pt-based CO oxidation catalyst with high resistance to SO2 poisoning according to claim 3, characterized in that: The load of K is 3.0 wt.%.
5. The method for preparing the alkali metal-modified Pt-based CO oxidation catalyst with high resistance to SO2 poisoning according to claim 1, characterized in that: The calcination temperature was 550 °C, the calcination time was 2 h, and the heating rate was 5 °C·min. -1 .
6. The method for preparing the alkali metal-modified Pt-based CO oxidation catalyst with high resistance to SO2 poisoning according to claim 1, characterized in that: The calcination atmosphere is air and oxygen.
7. The alkali metal modified Pt-based CO oxidation catalyst prepared by the method for preparing the highly SO2 poisoning-resistant alkali metal modified Pt-based CO oxidation catalyst according to any one of claims 1 to 6.
8. The application of the alkali metal modified Pt-based CO oxidation catalyst according to claim 7 in the CO oxidation reaction.
9. The application of the alkali metal-modified Pt-based CO oxidation catalyst according to claim 8 in the CO oxidation reaction, characterized in that: The catalytic conditions for the CO oxidation reaction were as follows: catalyst particle size of 40-60 mesh, CO to O2 ratio of 1:5, SO2 concentration of 10 ppm, and mass hourly space velocity (MSV) of 200,000 mL·g. cat -1 ·h -1 .
10. The application of the alkali metal-modified Pt-based CO oxidation catalyst according to claim 9 in the CO oxidation reaction, characterized in that: The CO catalytic oxidation reaction temperature range is 100-250 ℃, and the test temperature for resistance to SO2 poisoning is 220 ℃.