Three-dimensional ordered macroporous structure catalyst, catalyst composition and application

Abstract

This invention relates to the field of catalyst technology, and more particularly to three-dimensional ordered macroporous structure catalysts, catalyst compositions, and their applications. This includes the preparation of polymethyl methacrylate (PMMA) microsphere templates, wherein the prepared PMMA microsphere templates exhibit a red and / or green metallic luster; and the preparation of 3DOM La coated with active components. 0.5 K 0.5 Mn 0.97 Pd 0.03 O 3 The catalyst steps. It can simultaneously remove NO under aqueous atmosphere conditions. x The efficiency and capacity for treating exhaust gases such as CO, HC, and particulate matter can be improved to a certain extent.

Description

Three-dimensional ordered macroporous catalysts, catalyst compositions and applications Technical Field

[0001] This invention relates to the field of catalyst technology, and more particularly to three-dimensional ordered macroporous catalysts, catalyst compositions, and their applications. Background Technology

[0002] Increased ozone concentration has become second only to PM2.5. 2.5 Waste gas is a significant factor affecting air quality in my country. Therefore, improving the capacity for waste gas treatment has always been a research and development direction for those skilled in the art. Summary of the Invention

[0003] (a) Technical problems to be solved

[0004] The technical problem to be solved by the present invention is to provide a three-dimensional ordered macroporous structure catalyst, catalyst composition and application, so as to improve and enhance the existing waste gas treatment capacity and effect to a certain extent.

[0005] (II) Technical Solution

[0006] To address the aforementioned problems, in a first aspect, the present invention provides a method for preparing a three-dimensional ordered macroporous catalyst, comprising the following steps:

[0007] A polymethyl methacrylate (PMMA) microsphere template was prepared, and the prepared PMMA microsphere template exhibited a red and / or green metallic luster.

[0008] Preparation of 3DOM La coated with active components 0.5 K 0.5 Mn 0.97 Pd 0.03 O3 catalyst.

[0009] Furthermore, the preparation of the polymethyl methacrylate microsphere template includes:

[0010] Add methyl methacrylate containing p-hydroxybenzoic acid and potassium persulfate solution sequentially to distilled water;

[0011] After evaporation, a thin film of polymethyl methacrylate microsphere template that exhibits a red and / or green luster under natural light is obtained.

[0012] Furthermore, the preparation of 3DOM La coated with active components... 0.5 K 0.5 Mn 0.97 Pd 0.03 O3 catalysts include:

[0013] Weigh out lanthanum nitrate, potassium carbonate, manganese nitrate solution, and palladium chloride solution;

[0014] Lanthanum nitrate, potassium carbonate, manganese nitrate solution, and palladium chloride solution were dissolved in deionized water;

[0015] Add citric acid to obtain wet gel A;

[0016] The obtained wet gel A was added to an ethylene glycol-methanol mixture;

[0017] Add P123 template agent;

[0018] Add polymethyl methacrylate microsphere template;

[0019] Obtain the finished product.

[0020] Furthermore, the step of sequentially adding methyl methacrylate containing p-hydroxybenzoic acid and potassium persulfate solution to distilled water includes:

[0021] Add distilled water under water bath and magnetic stirring conditions;

[0022] Nitrogen gas is introduced into distilled water;

[0023] Add methyl methacrylate containing p-hydroxybenzoic acid;

[0024] Nitrogen gas is introduced again;

[0025] Add potassium persulfate solution to the reaction;

[0026] The reaction was carried out under nitrogen atmosphere to obtain a milky white mixture.

[0027] Furthermore, after adding the potassium persulfate solution, the process also includes:

[0028] The step involves rinsing the beaker containing dissolved potassium persulfate with distilled water and then pouring the rinsing solution into the reaction solution.

[0029] Furthermore, prior to the step of obtaining the finished product, the following steps are also included:

[0030] After adding the polymethyl methacrylate microsphere template, let it stand for 24 hours;

[0031] After filtration, place the sample in an oven at 50℃ to dry.

[0032] Segmented alternating atmosphere roasting.

[0033] Furthermore, the segmented alternating atmosphere calcination is as follows:

[0034] First stage: Under N2 atmosphere conditions, the temperature was raised from room temperature to 300℃ at a rate of 2℃ / min and an N2 flow rate of 50ml / min, and maintained for 3 hours before being lowered to room temperature;

[0035] Second section: Under air atmosphere conditions, the temperature is raised from room temperature to 300℃ at a rate of 2℃ / min and maintained for 2 hours; then raised to 700℃ at a rate of 2℃ / min and maintained for 4 hours; followed by natural cooling.

[0036] Secondly, this invention provides a three-dimensional ordered macroporous structure catalyst for the removal of NO under aqueous atmosphere conditions. x One or more of CO, HC, and particulate matter.

[0037] Thirdly, the present invention provides a catalyst composition comprising the above-described three-dimensional ordered macroporous structure catalyst.

[0038] Fourthly, the present invention provides a method for treating waste gas, the method comprising contacting the waste gas with the above-described three-dimensional ordered macroporous structure catalyst or the above-described catalyst composition.

[0039] (III) Beneficial Effects

[0040] The above-mentioned technical solution of the present invention has the following advantages: The three-dimensional ordered macroporous structure catalyst disclosed in the present invention can simultaneously remove NO under aqueous atmosphere conditions. x The efficiency and capacity for treating exhaust gases such as CO, HC, and particulate matter can be improved to a certain extent.

[0041] The accompanying drawings are provided for illustrative purposes only, and the proportions and quantities of the components in the drawings may not be consistent with the actual product.

[0042] Figure 1 shows the NOx conversion curves of lean and rich fuels according to the present invention; wherein, the upper part represents an anhydrous atmosphere; and the lower part represents a water-containing atmosphere.

[0043] Figure 2 shows the XRD patterns of different samples from this invention; wherein,

[0044] (a) 3DOM 0%La 0.5 K 0.5 Mn 0.97 Pd 0.03 O3;

[0045] (b) 3DOM 20% La 0.5 K 0.5 Mn 0.97 Pd 0.03 O3;

[0046] (c) 3DOM 30% La 0.5 K 0.5 Mn 0.97 Pd 0.03 O3;

[0047] (d) 3DOM 40% La 0.5 K0.5 Mn 0.97 Pd 0.03 O3

[0048] Figure 3 shows the CO2 concentration variation of different samples of the present invention under a water-containing atmosphere;

[0049] Figure 4 shows the SEM images of different samples from this invention;

[0050] Figure 5 shows TEM images of different samples from this invention;

[0051] Figure 6 shows the XPS spectra of different samples from this invention;

[0052] Figure 7 shows the NO-TPD curves of different samples of the present invention.

[0053] 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 only some embodiments of the present invention, not all embodiments. Based on the 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.

[0054] This invention utilizes PMMA microspheres as templates for loading active components. First, using methyl methacrylate, p-hydroxybenzoic acid, potassium persulfate, and distilled water as main raw materials, PMMA microspheres with red and / or green luster are obtained through steps such as water bath stirring and distillation, centrifugal washing, ultrasonic dispersion, and water bath evaporation in a nitrogen atmosphere. Then, using LaMnO3 perovskite with an ABO3 crystal structure as a matrix, K doping at the A-site changes the valence state of Mn at the B-site from divalent to trivalent or tetravalent, increasing the mobility of active oxygen. K also helps enhance the alkalinity of the catalytic material and improve the low-temperature combustion performance of soot particles. Furthermore, Pd substitution at the B-site improves the catalyst's resistance to high-temperature sintering and NOx storage performance, resulting in an active component capable of simultaneously removing NOx, CO, HC, and soot particles. Finally, the obtained active component solution is added to a solution of ethylene glycol, methanol, and P123 template agent mixed in a certain proportion, stirred at a constant temperature until the solution is clear, and then allowed to stand, dry, and calcined to obtain a three-dimensional ordered macroporous catalyst. This catalyst is effective in simultaneously removing NOx under aqueous atmosphere conditions. x It has a good effect on CO, HC and carbon soot particles.

[0055] Specifically: A method for preparing a three-dimensional ordered macroporous catalyst includes the following steps:

[0056] A polymethyl methacrylate (PMMA) microsphere template was prepared, and the prepared PMMA microsphere template exhibited a red and / or green metallic luster.

[0057] Specifically, it includes:

[0058] S1: Add methyl methacrylate containing p-hydroxybenzoic acid and potassium persulfate solution sequentially to distilled water.

[0059] Step S1 specifically includes:

[0060] S101: Using a 1000ml three-necked flask as the reaction vessel, add 650ml of distilled water under the conditions of a 70℃ water bath and magnetic stirring at 300rpm.

[0061] S102: Continuously purge nitrogen gas into distilled water for 30 minutes at a flow rate of 100 ml / min; connect a condenser to a three-necked flask, and connect a 30% ethanol solution to the outlet of the condenser to absorb the escaping methyl methyl propionate.

[0062] S103: Add methyl methacrylate containing 0.03% p-hydroxybenzoic acid by mass and tighten the stopper.

[0063] S104: Introduce nitrogen again for 15 minutes;

[0064] S105: Dissolve 0.2g of potassium persulfate in 20ml of distilled water to form a potassium persulfate solution. Pour the potassium persulfate solution into a three-necked flask to carry out the reaction; preferably, wash the beaker containing the dissolved potassium persulfate with 10ml of distilled water, and pour the washing solution into the reaction solution in the three-necked flask.

[0065] S106: Continue the reaction under nitrogen atmosphere for 45 minutes to obtain a milky white mixture.

[0066] S2: After evaporation, obtain a thin film-like polymethyl methacrylate microsphere template that displays a red and / or green luster under natural light.

[0067] Step S2 specifically includes:

[0068] S201: Pour the milky white mixture into 1500ml of distilled water and mix evenly.

[0069] S202: Centrifuge the above mixed liquid, remove the supernatant, leaving the solid layer in the centrifuge tube, mix with deionized water to prepare an emulsion of 3% PMMA by mass, and then ultrasonically disperse for 50 min to ensure uniform dispersion of polymethyl methacrylate microspheres. Centrifuge at 40,000 rpm for 50 min.

[0070] S203: Pour the prepared emulsion into a beaker and evaporate it to dryness in a water bath at 80°C until a thin film of polymethyl methacrylate microsphere template that shows a red and / or green luster under natural light is obtained.

[0071] Preparation of 3DOM La coated with active components 0.5 K 0.5 Mn 0.97 Pd 0.03 O3 catalyst.

[0072] Specifically, it includes:

[0073] S3: Weigh out lanthanum nitrate, potassium carbonate, manganese nitrate solution and palladium chloride solution according to the molar ratio of 9:1:9.7:0.3.

[0074] S4: Dissolve lanthanum nitrate, potassium carbonate, manganese nitrate solution and palladium chloride solution in deionized water.

[0075] S5: Dissolve citric acid in an appropriate amount of deionized water, and add the dissolved citric acid to the metal nitrate solution in step S4 according to the molar ratio of total metal ions to citric acid of 1:1.2. After uniform mixing, wet gel A is obtained.

[0076] S6: Add the obtained wet gel A to the ethylene glycol-methanol mixture and stir until the solution is clear. The volume ratio of ethylene glycol to methanol in the ethylene glycol-methanol mixture is 1:1.

[0077] S7: P123 template agent is added to the clear solution obtained in step S6.

[0078] S8: Weigh out polymethyl methacrylate (PMMA) microsphere templates at mass percentages of 20%, 30%, and 40% respectively; add the weighed PMMA microsphere templates to continue the reaction to obtain 3DOM 20% La 0.5 K 0.5 Mn 0.97 Pd 0.03 O3, 3DOM 30% La 0.5 K 0.5 Mn 0.97 Pd 0.03 O3, 3DOM 40% La 0.5 K 0.5 Mn 0.97 Pd 0.03 Three different experimental samples of O3 were left to stand for 24 hours.

[0079] S9: After filtration, dry in an oven at 50℃; then roast in alternating atmospheres in stages.

[0080] The preferred method for segmented alternating atmosphere roasting is:

[0081] S901: First stage: Under N2 atmosphere conditions, the temperature is raised from room temperature to 300℃ at a rate of 2℃ / min and an N2 flow rate of 50ml / min, and maintained for 3 hours before being reduced to room temperature;

[0082] S902: Second section: Under air atmosphere conditions, the temperature is increased from room temperature to 300℃ at a rate of 2℃ / min and maintained for 2 hours; the temperature is increased to 700℃ at a rate of 2℃ / min and maintained for 4 hours; then the temperature is allowed to cool naturally.

[0083] S10: Obtain the finished product.

[0084] This catalyst exhibits high NOx storage performance, low-temperature catalytic activity, and water resistance during NO catalytic reduction. Furthermore, the 3DOM structure improves the dispersibility of the active additive, enhancing its oxygen storage capacity under oxygen-rich conditions and its redox performance under oxygen-deficient conditions. This catalyst can provide technical support for pollution control in diesel machinery and bring certain economic and environmental benefits.

[0085] Experiment 1: As shown in Figure 1, this experiment illustrates alternating lean and rich fuel conditions under water and anhydrous conditions. The NO and NO2 conversion rates show that under lean fuel conditions, the introduction of a small amount of water enhances the catalyst's NOx storage performance, increasing the NOx storage equilibrium time (from 17 minutes to 22 minutes). However, the amount of NO2 generated does not increase accordingly. This indicates that after water introduction, NO is not primarily converted to NO2 for storage, but rather converted to other forms that promote the increase in NO conversion rate. This may be because the introduction of H2O competes with NOx for adsorption at alkaline sites, forming hydroxyl compounds that react with oxygen and NOx to form nitrates, thus promoting NO conversion. During the rich fuel stage (30-60 minutes), the desorption of NO2 under water conditions is significantly lower than under anhydrous conditions. This is because the adsorbed water or the formed hydroxyl compounds interact with the stored NOx, increasing the binding energy and affecting NOx desorption.

[0086] Experiment 2: As shown in Figure 2, 3DOM La with different active component loadings... 0.5 K 0.5 Mn 0.97 Pd 0.03 The XRD diffraction patterns of the O3-type catalysts all basically maintained the perovskite ABO3 configuration (JPCD#34-1181). The peak positions of the catalysts at 22.79°, 32.54°, 40.25°, 46.80°, 52.82°, 58.14°, 68.51°, and 77.98° were (101), (121), (220), (202), (222), (240), (400), and (160) crystal planes, respectively, corresponding to the characteristic peaks of perovskite. From the magnified image of the main characteristic peak on the right, it can be seen that the characteristic peaks of the 3DOM LaKMnPdO3 catalyst are shifted to smaller angles compared with the characteristic diffraction peaks of the catalyst before structural modification. This indicates that the macroporous structure of the 3DOM catalyst causes lattice expansion, resulting in a smaller diffraction angle.

[0087] Experiment 3: As shown in Figure 3, 3DOM La with different active component loadings... 0.5 K 0.5 Mn 0.97 Pd 0.03 CO2 concentration variation curves of O3-type catalysts. The results show that La modified with a three-dimensional ordered macroporous structure... 0.5 K 0.5 Mn 0.97 Pd 0.03 The selectivity of the O3 catalyst for N2 was improved compared to the unmodified version. With a catalyst loading of 30% active component, the lowest ignition temperature of soot reached 169℃, while the NOx to N2 yield reached a maximum of 67%, an increase of 34% compared to the unmodified version. This indicates that the three-dimensional ordered macroporous structure is more conducive to the desorption of stored NOx, i.e., its oxidation reaction with reducing gases.

[0088] Experiment 4: Referring to Figure 4, 3DOM La with different active component loadings... 0.5 K 0.5 Mn 0.97 Pd 0.03 SEM images of the O3 catalyst show that the polymethyl methacrylate microspheres are very uniform in size and arranged in a very orderly and regular manner.

[0089] As shown in Figure 4(a,b), the size of a single polymethyl methacrylate colloidal crystal template microsphere is 300±50 nm, and they are uniform in size and tightly packed. SEM images of different active component loadings reveal that all three catalysts with varying active component loadings formed uniformly sized, ordered spherical structures.

[0090] As shown in Figure 4(c,d), the catalyst with a 20% active component loading has a very uniform spherical structure and a particle size of approximately 40-50 nm.

[0091] As shown in Figure 4(e,f), the particle size of the catalyst with 30% active component loading is 50-60 nm.

[0092] As shown in Figure 4 (g,h), excessive loading of active components can lead to uneven dispersion of spherical catalyst particles and particle agglomeration. The particle size of catalysts with 40% active component loading is approximately 90-100 nm.

[0093] Experiment 5: Referring to Figure 5, 3DOM La with different active component loadings... 0.5 K 0.5 Mn 0.97 Pd 0.03 TEM images and energy dispersive spectroscopy (EDS) of the O3 catalyst. The results show that 3DOM La supported with 20% active component... 0.5 K 0.5 Mn0.97 Pd 0.03 HRTEM images of O3 allow for the calculation of the lattice spacing d (approximately 0.23 nm), which matches the 0.234 nm characteristic peak on the (211) crystal plane of the LaMnO3 standard sample (JCPDS PDF#89-2470). 3DOM LaMnO3 loaded with 30% active component... 0.5 K 0.5 Mn 0.97 Pd 0.03 The O3 catalyst has a lattice spacing d of 0.40 nm, which corresponds to the (004) crystal plane (0.398 nm) of La2CO5 detected by XRD. With increasing loading of the active component, the intensity of the perovskite characteristic peaks weakens, and K... 0.5 Mn2O4(H2O) 1.4 And La2CO5 metal oxide, while 3DOM La loaded with 40% active component 0.5 K 0.5 Mn 0.97 Pd 0.03 The O3 lattice spacing d is 0.68 nm, which is consistent with the K value shown in the X-ray diffraction results. 0.5 Mn2O4(H2O) 1.4 The (001) crystal plane (0.700 nm) corresponds to this, indicating that excessive loading of active components causes the catalytic material to exhibit a composite metal oxide structure. The EDS spectrum shows that the structurally modified 3DOMLa... 0.5 K 0.5 Mn 0.97 Pd 0.03 All doping elements were detected in the O3 catalyst. The 3DOM catalysts with 20% and 30% active component loadings were rich in La on the surface, but the K doping amount was less than the theoretical value, indicating that La enrichment occurred on the surface.

[0094] Experiment 6: Referring to Figure 6, 3DOM La with different active component loadings... 0.5 K 0.5 Mn 0.97 Pd 0.03 XPS spectra of the O3 catalyst, combined with elemental sensitivity algorithms to calculate the atomic concentration ratio, are shown in Table 1. The Oads / Olatt and Mn ratios of the three-dimensional ordered macroporous catalyst are also shown. 4+ / (Mn 3+ +Mn 2+ The atomic ratios of MnO3 and MnPdO3 are larger than those of LaKMnPdO3 catalysts, with a maximum Oads / Olatt ratio of 2.90 for 20% Oads / Olatt (compared to 1.35 for catalysts without templates). 4+ / (Mn 3+ +Mn 2+The value of 0.64 indicates that the three-dimensional ordered macroporous structure improves the electron mobility of the catalyst, significantly enhancing its catalytic activity. Furthermore, the 3DOM La catalyst loaded with 20% of the active component... 0.5 K 0.5 Mn 0.97 Pd 0.03 O3-type catalysts can better maintain the perovskite morphology and form more active oxygen species.

[0095] Table 1. Surface composition and atomic concentration ratio of O1s and Mn2p

[0096]

[0097] Experiment 7: Referring to Figure 7, 3DOM La with different active component loadings... 0.5 K 0.5 Mn 0.97 Pd 0.03 NO-TPD curves of O3-type catalysts. 3DOM La with 20%, 30%, and 40% active component loadings. 0.5 K 0.5 Mn 0.97 Pd 0.03 The NO desorption peaks of the O3-type catalyst were at 131℃, 145℃, and 139℃, respectively. Among them, the catalyst with a 30% loading of active component had the lowest NO desorption peak onset temperature at 95℃, indicating that the 30% loading of 3DOM La 0.5 K 0.5 Mn 0.97 Pd 0.03 The desorption peak of the O3 catalyst exhibits a wide temperature range. The desorption peaks of NO2 catalysts with three different active component loadings are located at 293℃, 338℃, and 316℃, respectively. Based on the preceding XRD and FT-IR analyses, the desorption peaks at lower temperatures are mainly attributed to nitrates stored on the perovskite, while those at higher temperatures are attributed to nitrates stored on potassium carbonate. This indicates that nitrates stored on perovskite are more readily desorbed than those stored on potassium carbonate. In terms of desorption capacity, the 30% active component loading of 3DOM La... 0.5 K 0.5 Mn 0.97 Pd 0.03 The O3 catalyst loading was significantly higher than the other two, which is consistent with the CO2 concentration change analysis results in the NOx-Soot removal experiment. Throughout the desorption process, the amount of NO2 gas desorbed was much less than that of NO, indicating that the stored NOx was mainly released as NO during desorption.

[0098] This invention provides a three-dimensional ordered macroporous structure catalyst for removing one or more of NOx, CO, HC, and soot particles under aqueous atmosphere conditions, especially for applications that can simultaneously remove NOx, CO, HC, and soot particles under aqueous atmosphere conditions.

[0099] NOx emitted by diesel trucks can rapidly convert into nitrates under unfavorable weather conditions of calm, stable conditions and high humidity. Nitrates are particulate matter (PM2.5) emitted by diesel trucks. 2.5 The component with the largest proportion and the fastest increasing concentration in the secondary components is an important precursor to ozone formation. However, due to the lower exhaust emission temperature, higher oxygen content, and the presence of large amounts of NOx and soot (the main source of PM), the three-way catalytic converter technology used in traditional gasoline vehicles cannot meet the emission requirements for purifying diesel vehicle exhaust. Furthermore, urea currently used in diesel vehicle aftertreatment suffers from a series of problems, including large storage tank footprints, easy crystallization of the solution, and ammonia escape. Therefore, strengthening emission control of diesel trucks and implementing effective purification treatment of diesel vehicle exhaust has become an urgent problem to be solved and is crucial for my country's air pollution prevention and control.

[0100] The main pollutants in diesel vehicle exhaust include PM, NOx, CO, and HC. Among them, CO and HC emissions are relatively low. Therefore, controlling diesel vehicle exhaust emissions mainly involves controlling the formation of PM and NO and reducing the direct emissions of PM and NOx. However, PM and NOx have different formation mechanisms and are contradictory. Reducing PM will increase NOx emissions.

[0101] Currently, the main after-treatment technologies for diesel vehicle exhaust emissions include: (1) Oxidation catalytic converter (OCC), mainly used to oxidize and remove soluble organic components (SOF) and hydrocarbons from PM; (2) Particulate filter (DPF) and its regeneration technology, used to filter and remove particulate matter such as soot; (3) Nitrogen oxide purification technology, mainly including selective catalytic reduction (SCR) and nitrogen oxide storage reduction (NSR); (4) Four-way catalytic technology that simultaneously purifies PM, HC, CO and NOx. A four-way catalyst that simultaneously removes four pollutants—CO, hydrocarbons (HC), soot, and NOx—on the same catalyst bed is an ideal after-treatment technology for diesel vehicle exhaust. However, the mechanism by which H2O in exhaust gases affects the performance of the four-way catalyst and the passivation problem have not been effectively solved, becoming one of the key factors hindering the practical application of the functional design of integrated catalysts.

[0102] Therefore, the three-dimensional ordered macroporous structure catalyst of this invention is particularly suitable for the characteristics of diesel truck exhaust gas, and can simultaneously and efficiently remove NOx, CO, HC and soot particles in a water-containing atmosphere, thereby greatly improving the exhaust gas treatment capacity of diesel trucks.

[0103] This invention is not limited to diesel trucks, but can also be used for diesel excavators, diesel loaders, diesel fishing boats, diesel generator sets, and other devices.

[0104] This invention also provides a catalyst composition comprising, but not limited to, the three-dimensional ordered macroporous structure catalyst described above. For example, by using the catalyst disclosed in this invention in combination with any co-catalyst required by those skilled in the art, it can be applied to the treatment of waste gases with more complex compositions. Alternatively, depending on the composition of the waste gas, the catalyst disclosed in this invention can be used in conjunction with other existing catalysts to treat waste gases with complex compositions to achieve a specific waste gas treatment objective.

[0105] This invention also provides a method for treating exhaust gas, the method comprising contacting the exhaust gas with the aforementioned three-dimensional ordered macroporous structure catalyst or the aforementioned catalyst composition. For example, a structure for holding the aforementioned three-dimensional ordered macroporous structure catalyst or the aforementioned catalyst composition is provided at the front end of the exhaust pipe of a diesel truck. After the exhaust gas from the diesel truck is decomposed by contact with the aforementioned three-dimensional ordered macroporous structure catalyst or the aforementioned catalyst composition, it is discharged through the exhaust pipe of the diesel truck. For example, it can also be applied to the exhaust gas treatment of certain equipment with diesel engines, whereby the aforementioned three-dimensional ordered macroporous structure catalyst or the aforementioned catalyst composition is contacted with the exhaust gas to decompose the exhaust gas to meet emission standards before it is discharged.

[0106] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that not every embodiment contains only one independent technical solution, and in the absence of conflict between solutions, the various technical features mentioned in each embodiment can be combined in any way to form other implementation methods that can be understood by those skilled in the art.

[0107] Furthermore, without departing from the scope of the present invention, modifications to the technical solutions described in the foregoing embodiments, or equivalent substitutions of some of the technical features, shall not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for treating waste gas, the method comprising contacting the waste gas with a catalyst prepared by a method for preparing a three-dimensional ordered macroporous structure catalyst, for simultaneously removing NOx, CO, HC, and soot particles under a water-containing atmosphere; the method for preparing the three-dimensional ordered macroporous structure catalyst comprises the following steps: preparing a polymethyl methacrylate microsphere template; adding distilled water under water bath and magnetic stirring conditions; introducing nitrogen gas into the distilled water; adding methyl methacrylate containing p-hydroxybenzoic acid; and introducing nitrogen gas again; Add potassium persulfate solution to carry out the reaction; wash the beaker containing potassium persulfate with distilled water and pour the washing solution into the reaction solution; react under nitrogen atmosphere to obtain a milky white mixture; evaporate to dryness to obtain a thin film-like polymethyl methacrylate microsphere template that shows a red and / or green metallic luster under natural light; Preparation of 3DOM La coated with active components 0.5 K 0.5 Mn 0.97 Pd 0.03 O3 catalyst: Weigh out lanthanum nitrate, potassium carbonate, manganese nitrate solution, and palladium chloride solution; dissolve lanthanum nitrate, potassium carbonate, manganese nitrate solution, and palladium chloride solution in deionized water; Citric acid was added to obtain wet gel A; the obtained wet gel A was added to a mixture of ethylene glycol and methanol; P123 template agent was added; polymethyl methacrylate microsphere template was added; after adding the polymethyl methacrylate microsphere template, the mixture was allowed to stand for 24 hours; after filtration, it was placed in an oven at 50°C for drying; the mixture was then calcined in alternating atmospheres in stages: the first stage: under N2 atmosphere, the temperature was increased from room temperature to 300°C at a rate of 2°C / min and a flow rate of 50 ml / min, and maintained for 3 hours before being reduced to room temperature; Second stage: Under air atmosphere conditions, the temperature is increased from room temperature to 300℃ at a rate of 2℃ / min and maintained for 2 hours; the temperature is increased to 700℃ at a rate of 2℃ / min and maintained for 4 hours; then the temperature is allowed to cool naturally to obtain the finished product.

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