Low-temperature denitration and decarburization catalyst, preparation method and application
By preparing a Pt/CeO2 single-atom catalyst and combining it with a compound surfactant, the problem of CO and NOx removal in flue gas at low temperatures was solved, achieving efficient low-temperature denitrification and decarbonization. The catalyst exhibited excellent stability and activity in flue gas purification.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 合肥中亚环保科技有限公司
- Filing Date
- 2026-03-10
- Publication Date
- 2026-06-09
AI Technical Summary
Existing technologies are insufficient to efficiently remove CO and NOx pollutants from flue gas under low-temperature conditions, and the application potential of CO-SCR denitrification technology has not been fully realized.
Pt/CeO2 single-atom catalysts were prepared by dispersing cerium and platinum sources in anhydrous ethanol and then completely combusting and evaporating them in a tubular combustion furnace. During the co-precipitation process, lauramide propyl hydroxysulfonate betaine and quaternary ammonium salt surfactants were combined to achieve synergistic regulation of dispersion-nucleation-deposition-pore structure. Combined with the introduction of iron sources, a reversible interfacial redox cycle channel was formed, which enhanced the migration and replenishment capacity of reactive oxygen species.
It exhibits excellent denitrification and decarbonization performance under low temperature conditions, with a denitrification rate of 96% and a decarbonization rate of 98%. The catalyst stability and anti-deactivation ability are improved, and the reaction rate remains stable.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of catalyst technology, and in particular to low-temperature denitrification and decarbonization catalysts, preparation methods and applications. Background Technology
[0002] CO, a colorless and odorless gas, is widely present in high-energy industries such as building materials and waste incineration. In recent years, CO-SCR denitrification technology has attracted widespread research interest in academia. This method can simultaneously remove both CO and NOx pollutants from flue gas. As a resource-saving means of controlling NOx, CO-SCR has even broader application potential.
[0003] Therefore, the research and application of designing and developing noble metal-doped composite catalysts in conjunction with industrial furnace flue gas denitrification and carbon removal technology will have advantages such as pollution reduction, carbon reduction, energy saving and environmental protection. Summary of the Invention
[0004] Based on the technical problems existing in the background technology, the present invention proposes a low-temperature denitrification and decarbonization catalyst, preparation method and application. The prepared catalyst has excellent denitrification and decarbonization performance under low temperature conditions and can meet the requirements of efficient catalytic purification of flue gas under low temperature conditions.
[0005] The present invention proposes a method for preparing a low-temperature denitrification and decarbonization catalyst, the method steps of which are as follows:
[0006] S1: Disperse the cerium source and platinum source in anhydrous ethanol to obtain a precursor solution;
[0007] S2: The precursor solution is injected into a tubular combustion furnace fueled by hydrogen. After complete combustion and evaporation under oxygen conditions, a Pt / CeO2 single-atom catalyst is obtained.
[0008] S3: An iron source, a Pt / CeO2 single-atom catalyst, and a surfactant are dispersed in deionized water, and then ammonia is added for co-precipitation. The product is then separated, washed, dried, and calcined to obtain a low-temperature denitrification and decarbonization catalyst.
[0009] Preferably, the cerium source in S1 is one of cerium nitrate and its hydrate;
[0010] And / or, the platinum source is one or more of chloroplatinic acid and its hydrate, platinum nitrate and its hydrate;
[0011] And / or, the molar ratio of cerium source to platinum source is 1:0.05-0.15.
[0012] Preferably, the flow rate of hydrogen in S2 is 1.0-2.0 L / min; the pressure of oxygen is 1-2 bar, and the flow rate is 10.0-12.0 L / min.
[0013] Preferably, the surfactant in S3 is composed of lauramidopropyl hydroxysulfonate and quaternary ammonium salt surfactant in a mass ratio of 3-5:1.
[0014] Preferably, the quaternary ammonium salt surfactant is prepared as follows: N,N-dimethylethylenediamine and diethyl malonate are mixed and reacted in N,N-dimethylformamide to obtain an intermediate product; the intermediate product and myristyl chloride are then refluxed in anhydrous ethanol, and after the reaction is completed, the quaternary ammonium salt surfactant is obtained by rotary evaporation and recrystallization.
[0015] Preferably, the molar ratio of N,N-dimethylethylenediamine to diethyl malonate is 2-4:1;
[0016] And / or, the conditions for the mixed reaction are a temperature of 130-150℃ and a time of 5-10h;
[0017] And / or, the molar ratio of the intermediate to myristyl chloride is 1:8-12;
[0018] And / or, the reflux reaction conditions are a temperature of 70-90℃ and a time of 12-36h.
[0019] Preferably, the iron source in S3 is one or more of ferric nitrate and its hydrate, ferric sulfate and its hydrate, and ferric chloride and its hydrate;
[0020] And / or, the molar ratio of iron source to cerium source is 0.1-0.2:1;
[0021] And / or, the amount of surfactant added is 1-5% of the mass of the Pt / CeO2 single-atom catalyst.
[0022] Preferably, the calcination conditions in S3 are: temperature 350-450℃, time 24-36h.
[0023] The low-temperature denitrification and decarbonization catalyst proposed in this invention is prepared by the above-described preparation method.
[0024] The present invention proposes the application of a low-temperature denitrification and decarbonization catalyst in flue gas purification, the low-temperature denitrification and decarbonization catalyst being described above.
[0025] Beneficial technical effects of the present invention:
[0026] (1) This invention uses the route of "ethanol precursor solution → complete combustion and evaporation in a tubular combustion furnace → rapid quenching and fixing" to prepare Pt / CeO2 single-atom catalysts. This allows Pt to preferentially anchor itself to the surface defects and oxygen vacancies of CeO2 at highly dispersed single-atom / atomic-level sites, thus avoiding the growth and aggregation of Pt nanoparticles that are prone to occur in conventional impregnation-calcination routes. The reversible CeO2 bonding between these single-atom sites and CeO2... 4+ / Ce3+ The transformations form a tight electronic coupling relationship, making it easier to trigger the generation and migration of active oxygen (adsorbed oxygen / defective oxygen) on the CeO2 surface. This results in an earlier activation response and a more stable reaction rate under low-temperature flue gas conditions. At the same time, due to the high dispersion of Pt sites, the number of effective active sites per unit of noble metal load is increased, enabling the catalytic system to still have a high reaction driving force at low temperatures. This provides an "accessible and coupled" highly active substrate for the subsequent Fe interface construction.
[0027] (2) In the co-precipitation process, this invention achieves synergistic regulation of the entire process of "dispersion-nucleation-deposition-pore structure" through the combination of lauramidopropyl hydroxysulfonate betaine and quaternary ammonium salt surfactant. Lauramidopropyl hydroxysulfonate betaine can significantly reduce interfacial tension and form a flexible hydration adsorption layer in the aqueous phase, transforming the Pt / CeO2 single-atom support in the co-precipitation medium from "solid particles that are prone to secondary aggregation" to "stable and dispersed interfacial activated particles", thereby providing a uniform attachment substrate for Fe hydrolysis / precipitation species; the quaternary ammonium salt surfactant has stable cationic head groups and long-chain hydrophobic tail groups, and introduces the weak coordination and hydrogen bonding ability brought by the malonic acid ester / amide skeleton, which enables it to attach to Fe 3+ The hydrolysis intermediate undergoes "electrostatic traction + weak complexation confinement," inhibiting transient flocculation and disordered growth. The combination of these two components forms an ion-associative / mixed micelle structure: on the one hand, betaine provides an electrical buffer and hydration stabilizing layer, reducing the risk of bridging flocculation caused by the strong positive charge of the quaternary ammonium salt; on the other hand, the quaternary ammonium salt provides directional anchoring and confinement templates, making Fe more inclined to "nucleate in situ - deposit in a thin layer - uniformly coat / attach in dots" on the Pt / CeO2 surface. This achieves a coupling effect of "stable dispersion of the carrier - controlled deposition of Fe - uniform construction of the interface." This synergy transforms the precipitation process from "spontaneous growth of the bulk phase in solution" to "directional generation of the interface" through electrical complementarity and structural template.
[0028] (3) The introduction of Fe in this invention enables the formation of more Lewis acid sites / surface hydroxyl sites on the surface of the system that can participate in adsorption activation, while Fe 3+ / Fe 2+ With Ce 4+ / Ce 3+A reversible interfacial redox cycle channel is constructed between the catalyst and the support, enhancing the migration and replenishment of reactive oxygen species. Single-atom Pt sites more readily trigger key activation steps under low-temperature conditions and form close-proximity coupling with the Fe-O-Ce interface. The combined effect of these three factors transforms the reaction from a "volume-diffusion-limited random collision mode" to a synergistic pathway of "interfacial adsorption and enrichment - directional electron / oxygen migration - continuous conversion." In denitrification, this improves the adsorption and conversion efficiency of nitrogen oxides at low temperatures; in decarbonization, it exhibits more effective low-temperature activation and continuous conversion capabilities for carbon oxides / carbon-containing pollutants in flue gas. Furthermore, due to the more uniform interfacial structure and the stronger bond between Fe and the support, the catalyst's stability and resistance to deactivation under conditions such as water content are simultaneously enhanced. Detailed Implementation
[0029] The present invention will be further explained below with reference to specific embodiments. Example 1
[0030] 1 mmol of cerium nitrate and 0.1 mmol of chloroplatinic acid were dispersed in anhydrous ethanol to obtain a precursor solution. The precursor solution was injected into a tubular combustion furnace fueled by hydrogen and completely combusted and evaporated under oxygen conditions to obtain a Pt / CeO2 single-atom catalyst. The Pt / CeO2 single-atom catalyst was dispersed in deionized water, and then a quaternary ammonium salt surfactant, lauramide propyl hydroxysulfonyl betaine and an iron source were added in sequence. Ammonia water was then added for co-precipitation. The product was separated, washed, dried and calcined to obtain a low-temperature denitrification and decarbonization catalyst.
[0031] The hydrogen flow rate was 1.5 L / min; the oxygen pressure was 1.5 bar and the flow rate was 11.0 L / min; the calcination conditions were: temperature 400℃ and time 30 h.
[0032] The surfactant is composed of lauramidopropyl hydroxysulfonate and quaternary ammonium salt surfactant in a mass ratio of 4:1; the amount of surfactant added is 3% of the mass of the Pt / CeO2 single-atom catalyst.
[0033] The preparation method of quaternary ammonium salt surfactant is as follows: N,N-dimethylethylenediamine and diethyl malonate are mixed and reacted in N,N-dimethylformamide to obtain an intermediate product; the intermediate product and myristyl chloride are then refluxed in anhydrous ethanol. After the reaction is completed, the quaternary ammonium salt surfactant is obtained by rotary evaporation and recrystallization.
[0034] The molar ratio of N,N-dimethylethylenediamine to diethyl malonate was 3:1; the mixed reaction conditions were 140℃ for 8 hours; the molar ratio of the intermediate product to myristyl chloride was 1:10; and the reflux reaction conditions were 80℃ for 24 hours. Example 2
[0035] 1 mmol of cerium nitrate and 0.05 mmol of chloroplatinic acid were dispersed in anhydrous ethanol to obtain a precursor solution. The precursor solution was injected into a tubular combustion furnace fueled by hydrogen and completely combusted and evaporated under oxygen conditions to obtain a Pt / CeO2 single-atom catalyst. The Pt / CeO2 single-atom catalyst was dispersed in deionized water, and then a quaternary ammonium salt surfactant, lauramide propyl hydroxysulfonyl betaine and 0.1 mmol of iron source were added in sequence. Ammonia water was then added for co-precipitation. The product was separated, washed, dried and calcined to obtain a low-temperature denitrification and decarbonization catalyst.
[0036] The hydrogen flow rate was 1.0 L / min; the oxygen pressure was 1 bar and the flow rate was 10.0 L / min; the calcination conditions were: temperature 350℃ and time 36 h.
[0037] The surfactant is composed of lauramidopropyl hydroxysulfonate and quaternary ammonium salt surfactant in a mass ratio of 3:1; the amount of surfactant added is 1% of the mass of the Pt / CeO2 single-atom catalyst.
[0038] The preparation method of quaternary ammonium salt surfactant is as follows: N,N-dimethylethylenediamine and diethyl malonate are mixed and reacted in N,N-dimethylformamide to obtain an intermediate product; the intermediate product and myristyl chloride are then refluxed in anhydrous ethanol. After the reaction is completed, the quaternary ammonium salt surfactant is obtained by rotary evaporation and recrystallization.
[0039] The molar ratio of N,N-dimethylethylenediamine to diethyl malonate was 2:1; the mixed reaction conditions were 130℃ for 10 h; the molar ratio of intermediate product to myristyl chloride was 1:8; and the reflux reaction conditions were 70℃ for 36 h. Example 3
[0040] 1 mmol of cerium nitrate and 0.15 mmol of chloroplatinic acid were dispersed in anhydrous ethanol to obtain a precursor solution. The precursor solution was injected into a tubular combustion furnace fueled by hydrogen and completely combusted and evaporated under oxygen conditions to obtain a Pt / CeO2 single-atom catalyst. The Pt / CeO2 single-atom catalyst was dispersed in deionized water, and then a quaternary ammonium salt surfactant, lauramide propyl hydroxysulfonate betaine, and 0.2 mmol of iron source were added in sequence. Ammonia water was then added for co-precipitation. The product was separated, washed, dried, and calcined to obtain a low-temperature denitrification and decarbonization catalyst.
[0041] The hydrogen flow rate was 2.0 L / min; the oxygen pressure was 2 bar and the flow rate was 12.0 L / min; the calcination conditions were: temperature 450℃ and time 36 h.
[0042] The surfactant is composed of lauramidopropyl hydroxysulfonate and quaternary ammonium salt surfactant in a mass ratio of 5:1; the amount of surfactant added is 5% of the mass of the Pt / CeO2 single-atom catalyst.
[0043] The preparation method of quaternary ammonium salt surfactant is as follows: N,N-dimethylethylenediamine and diethyl malonate are mixed and reacted in N,N-dimethylformamide to obtain an intermediate product; the intermediate product and myristyl chloride are then refluxed in anhydrous ethanol. After the reaction is completed, the quaternary ammonium salt surfactant is obtained by rotary evaporation and recrystallization.
[0044] The molar ratio of N,N-dimethylethylenediamine to diethyl malonate was 4:1; the mixed reaction conditions were 150℃ for 5 hours; the molar ratio of the intermediate product to myristyl chloride was 1:12; and the reflux reaction conditions were 90℃ for 12 hours.
[0045] Comparative Example 1
[0046] The surfactant used in this scheme is lauramidopropyl hydroxysulfonate betaine, and all other conditions are the same as in Example 1.
[0047] Comparative Example 2
[0048] The surfactant used in this scheme is a quaternary ammonium salt surfactant, and all other conditions are the same as in Example 1.
[0049] The denitrification and decarbonization performance of the catalysts prepared in Example 1, Comparative Example 1, and Comparative Example 2 was tested, and the test results are shown in Table 1.
[0050] Detection method: using 500 ppm NO x The experiment was conducted using gases containing 500 ppm NH3, 1000 ppm CO, 10% O2, and 89% N2, with a space velocity of 50,000 h⁻¹. - The test temperature was 145℃, and the test results are shown in Table 1.
[0051] Table 1 Catalyst performance test results
[0052]
[0053] As can be seen from the test results of Example 1 in Table 1, the catalyst prepared by the present invention has excellent denitrification and decarbonization performance at low temperature (145℃), with a denitrification rate of 96% and a decarbonization rate of 98%.
[0054] As can be seen from the experimental results of Example 1 and Comparative Examples 1 and 2 in Table 1, the denitrification and decarbonization performance of the catalyst prepared using a single surfactant is significantly lower than that of the catalyst prepared using a combination of two surfactants. This indicates that the lauramidopropyl hydroxysulfonate betaine and the quaternary ammonium salt surfactant of this application have a synergistic promoting effect on improving the denitrification and decarbonization performance of the catalyst. This is because the present invention achieves synergistic regulation of the entire process of "dispersion-nucleation-deposition-pore structure" through the combination of lauramidopropyl hydroxysulfonate betaine and the quaternary ammonium salt surfactant during the co-precipitation process. Lauroamide propyl hydroxysulfonate betaine significantly reduces interfacial tension and forms a flexible hydration adsorption layer in the aqueous phase, transforming the Pt / CeO2 single-atom support from "easily agglomerated solid particles" to "stable, dispersed, interfacially activated particles" in the coprecipitation medium. This provides a uniform substrate for the adhesion of Fe hydrolysis / precipitation species. The quaternary ammonium salt surfactant possesses stable cationic head groups and long-chain hydrophobic tail groups, and introduces weak coordination and hydrogen bonding capabilities from the malonate / amide skeleton, enabling it to adhere to Fe... 3+ The hydrolysis intermediate undergoes "electrostatic traction + weak complexation confinement," inhibiting transient flocculation and disordered growth. The combination of these two components forms an ion-associative / mixed micelle structure: on the one hand, betaine provides an electrical buffer and hydration stabilizing layer, reducing the risk of bridging flocculation caused by the strong positive charge of the quaternary ammonium salt; on the other hand, the quaternary ammonium salt provides directional anchoring and confinement templates, making Fe more inclined to "nucleate in situ - deposit in a thin layer - uniformly coat / attach in dots" on the Pt / CeO2 surface. This achieves a coupling effect of "stable dispersion of the carrier - controlled deposition of Fe - uniform construction of the interface." This synergy transforms the precipitation process from "spontaneous growth of the bulk phase in solution" to "directional generation of the interface" through electrical complementarity and structural template.
[0055] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application. The scope of this application is defined by the appended claims and their equivalents, all of which should be included within the protection scope of this application.
Claims
1. A method for preparing a low-temperature denitrification and decarbonization catalyst, characterized in that, The steps are as follows: S1: Disperse the cerium source and platinum source in anhydrous ethanol to obtain a precursor solution; S2: The precursor solution is injected into a tubular combustion furnace fueled by hydrogen. After complete combustion and evaporation under oxygen conditions, a Pt / CeO2 single-atom catalyst is obtained. S3: An iron source, a Pt / CeO2 single-atom catalyst, and a surfactant are dispersed in deionized water, and then ammonia is added for co-precipitation. The product is then separated, washed, dried, and calcined to obtain a low-temperature denitrification and decarbonization catalyst.
2. The preparation method of the low-temperature denitrification and decarbonization catalyst according to claim 1, characterized in that, The cerium source in S1 is one of cerium nitrate and its hydrate; And / or, the platinum source is one or more of chloroplatinic acid and its hydrate, platinum nitrate and its hydrate; And / or, the molar ratio of cerium source to platinum source is 1:0.05-0.
15.
3. The method for preparing the low-temperature denitrification and decarbonization catalyst according to claim 1, characterized in that, In S2, the hydrogen flow rate is 1.0-2.0 L / min; the oxygen pressure is 1-2 bar, and the flow rate is 10.0-12.0 L / min.
4. The preparation method of the low-temperature denitrification and decarbonization catalyst according to claim 1, characterized in that, The surfactant in S3 is composed of lauramidopropyl hydroxysulfonate and quaternary ammonium salt surfactant in a mass ratio of 3-5:
1.
5. The preparation method of the low-temperature denitrification and decarbonization catalyst according to claim 4, characterized in that, The preparation method of the quaternary ammonium salt surfactant is as follows: N,N-dimethylethylenediamine and diethyl malonate are mixed and reacted in N,N-dimethylformamide to obtain an intermediate product; the intermediate product and myristyl chloride are then refluxed in anhydrous ethanol, and after the reaction is completed, the quaternary ammonium salt surfactant is obtained by rotary evaporation and recrystallization.
6. The method for preparing the low-temperature denitrification and decarbonization catalyst according to claim 5, characterized in that, The molar ratio of N,N-dimethylethylenediamine to diethyl malonate is 2-4:1; And / or, the conditions for the mixed reaction are a temperature of 130-150℃ and a time of 5-10h; And / or, the molar ratio of the intermediate to myristyl chloride is 1:8-12; And / or, the reflux reaction conditions are a temperature of 70-90℃ and a time of 12-36h.
7. The method for preparing the low-temperature denitrification and decarbonization catalyst according to claim 1, characterized in that, The iron source in S3 is one or more of the following: ferric nitrate and its hydrate, ferric sulfate and its hydrate, and ferric chloride and its hydrate. And / or, the molar ratio of iron source to cerium source is 0.1-0.2:1; And / or, the amount of surfactant added is 1-5% of the mass of the Pt / CeO2 single-atom catalyst.
8. The method for preparing the low-temperature denitrification and decarbonization catalyst according to claim 1, characterized in that, The calcination conditions in S3 are: temperature 350-450℃, time 24-36h.
9. A low-temperature denitrification and decarbonization catalyst, characterized in that, It is prepared by the preparation method according to any one of claims 1-8.
10. The application of a low-temperature denitrification and decarbonization catalyst in flue gas purification, characterized in that, The low-temperature denitrification and decarbonization catalyst is as described in claim 9.