CN113117722A - For normal temperature NH3Preparation method of-SCR denitration atomic-level active site catalyst - Google Patents

For normal temperature NH3Preparation method of-SCR denitration atomic-level active site catalyst Download PDF

Info

Publication number
CN113117722A
CN113117722A CN202110443261.0A CN202110443261A CN113117722A CN 113117722 A CN113117722 A CN 113117722A CN 202110443261 A CN202110443261 A CN 202110443261A CN 113117722 A CN113117722 A CN 113117722A
Authority
CN
China
Prior art keywords
atomic
active site
catalyst
temperature
site catalyst
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
CN202110443261.0A
Other languages
Chinese (zh)
Inventor
丁辉
赵梓舒
徐曦萌
赵丹
刘蕊
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Tianjin University
Original Assignee
Tianjin University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Tianjin University filed Critical Tianjin University
Priority to CN202110443261.0A priority Critical patent/CN113117722A/en
Publication of CN113117722A publication Critical patent/CN113117722A/en
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
    • B01J27/24—Nitrogen compounds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/86—Catalytic processes
    • B01D53/8621—Removing nitrogen compounds
    • B01D53/8625—Nitrogen oxides
    • B01D53/8628—Processes characterised by a specific catalyst
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/20—Reductants
    • B01D2251/206—Ammonium compounds
    • B01D2251/2062—Ammonia

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Environmental & Geological Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Organic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Biomedical Technology (AREA)
  • Analytical Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Exhaust Gas Treatment By Means Of Catalyst (AREA)
  • Catalysts (AREA)

Abstract

The invention provides a method for normal temperature NH3A preparation method of an atomic-level active site catalyst for SCR denitration, which relates to the technical field of catalyst preparation. The catalyst of the invention is prepared by adopting a direct calcination method, a liquid phase doping method or an impregnation method at g-C3N4Bimetal is loaded on a carrier to prepare a semi-finished product of the atomic-scale active site catalyst, and then the semi-finished product is calcined to prepare the catalyst, wherein the bimetal is Ni and La. According to the invention, the active sites on the catalyst carrier are distributed in an atomic scale by adjusting the calcination treatment process parameters. The catalyst prepared by the method has excellent performance, and has higher NO conversion rate under the normal temperature condition, and the conversion rate is over 93 percent.

Description

For normal temperature NH3Preparation method of-SCR denitration atomic-level active site catalyst
Technical Field
The invention relates to the technical field of catalyst processing, in particular to a catalyst for normal-temperature NH3Preparation of atomic-scale active-site catalyst for SCR denitrationThe preparation method is as follows.
Background
With the rapid development of the world economy, the atmospheric environmental problem becomes more serious. The atmospheric pollutants in China are various, wherein the serious pollution is the most common nitrogen oxides, and the nitrogen oxides generally comprise NO and NO2And N2O, and the like. NOxAs one of the main pollution gases in the air, it causes a series of environmental problems such as acid rain, ozone layer destruction, photochemical smog, water pollution, greenhouse effect, increase of toxic substances and particle formation, etc.
The Selective Catalytic Reduction (SCR) is the most common method for eliminating nitrogen oxides at present, and the SCR selective catalytic reduction method uses ammonia gas or ammonia water as a reducing agent, and selectively reduces the nitrogen oxides into nitrogen gas and water under the action of a catalyst and a certain temperature. The addition of the SCR catalyst can effectively reduce the activation energy required by the reaction of the nitrogen oxides and ammonia gas and effectively improve the removal rate of the nitrogen oxides.
Due to the good economical efficiency of the low-temperature selective catalytic reduction method, the method attracts the attention of environmental protection research workers in various countries and becomes a hotspot of SCR research in recent years. But in the presence of water vapor and SO2In the presence of such a catalyst, the stability and selectivity of the catalyst are poor. At present, research on low-temperature SCR denitration catalysts mainly focuses on improvement of catalytic efficiency and sulfur-resistant and water-resistant performance, and is mainly realized by technical means such as catalyst doping modification, catalyst carrier replacement, preparation method improvement and the like. The carbon material (such as graphene, activated carbon, doped carbon, carbon nitride and the like) has the unique performance of improving the sulfur poisoning resistance of the catalyst, is large in specific surface area and multiple in pore structure, can be widely applied to SCR denitration as a carrier, and also has low-temperature SCR activity. Graphite-like phase carbon nitride (g-C)3N4) Has the characteristics of easy preparation, low cost, proper electronic structure and the like, and is a promising carrier of single atom. Some researches also use rare earth elements in developing industrial waste gas denitration catalysts, the mainly used rare earth elements comprise lanthanum, praseodymium, neodymium, cerium and the like, the proportion of noble metals and transition metals in the catalysts can be greatly reduced after the rare earth elements are added, and in carriers, the rare earth elements can improve the mechanical strength and stabilityAnd (5) performing qualitative determination.
At present, the SCR technology and the catalyst system thereof with good application effect in the range of 180-420 ℃ (including low temperature and medium and high temperature) have been formed in China, but the problem of normal-temperature SCR denitration still needs to be broken through. Acidity and excellent redox performance are key factors of the SCR catalyst with a wide active temperature window, and influence on NH3And adsorption/activation of NOx. The low temperature activity is mainly determined by the redox properties, and the high temperature activity is associated with acidity. In general, adsorption of NH3 at the acid site is easier at low temperatures, while oxidation of the reduced NH in situ3And NO activation is relatively difficult. Therefore, there is a need to develop a normal-temperature SCR denitration catalyst that is feasible under normal-temperature conditions, has excellent oxidation-reduction performance, is efficient and stable, and has a wide prospect in industrial applications.
Disclosure of Invention
In view of the above, the present invention provides a method for NH at room temperature3A preparation method of an atomic-level active site catalyst for SCR denitration. The catalyst prepared by the method has atomic-level active sites, can have remarkable catalytic activity and stability at normal temperature, and reduces denitration energy consumption.
The invention is used for normal temperature NH3The preparation method of the atomic-level active site catalyst for SCR denitration comprises the following steps of firstly adopting a direct calcination method, a liquid phase doping method or an impregnation method to perform reaction at g-C3N4Loading bimetal on a carrier to prepare a semi-finished product of the atomic-scale active site catalyst, and then calcining the semi-finished product to prepare the catalyst, wherein the bimetal is Ni and La;
the calcination treatment comprises the following steps:
s4-1, calcining the semi-finished product of the atomic-scale active site catalyst in a tubular furnace, wherein the nitrogen flow rate is 100-200mLmin-1The calcination temperature is 800-900 ℃, and the calcination time is 2-4 h;
s4-2, and then reducing for 3-4h under the conditions of hydrogen-argon mixed atmosphere and temperature of 500-550 ℃.
Wherein in some embodiments, g-C of the present invention3N4The carrier is polymerized by heatThe preparation method comprises the following steps:
accurately weighing 10g of melamine, placing the melamine into a covered crucible, placing the crucible into a muffle furnace, calcining the melamine for 3 to 4 hours at 550 to 580 ℃, and raising the temperature for 5 to 7 ℃ min-1Keeping for 2 h; naturally cooling to room temperature, taking out the massive sample, grinding into uniform powder to obtain g-C3N4And (3) a carrier.
Preferably, the direct calcination process of the present invention for preparing the atomic-scale active site catalyst comprises the following steps:
s1-1, weighing g-C according to the mass ratio of (8-10) to (6-8) to (3-5) to (1-3)3N4、H3BO3、Ni(NO3)2·6H2O、La(NO3)3Grinding and mixing uniformly;
s1-2, placing the uniformly mixed raw materials into a muffle furnace, calcining for 3-5 hours at 500-600 ℃ to obtain a semi-finished product of the atomic-scale active site catalyst, and placing the muffle furnace into the muffle furnace to heat the semi-finished product at a rate of 5-7 ℃ for min-1，。
Preferably, the preparation of the atomic-scale active site catalyst by the liquid phase doping method comprises the following steps:
s2-1, weighing g-C according to the mass ratio of (8-10) to (6-8) to (3-5) to (1-3)3N4、H3BO3、Ni(NO3)2·6H2O、La(NO3)3Mixing, adding ethanol and deionized water to obtain solution, and performing ultrasonic treatment for 1-3 h;
s2-2, performing ultrasonic treatment, performing magnetic stirring at the temperature of 60-70 ℃ for 3 hours, and performing magnetic stirring at the temperature of 85-90 ℃ for 3 hours; and finally, drying for 3 hours at the temperature of 100-140 ℃, and grinding uniformly to obtain a semi-finished product of the atomic-level active site catalyst.
More preferably, the volume ratio of the ethanol to the deionized water in step S2-1 of the present invention is 1: 1.
Preferably, the impregnation method for preparing the atomic-scale active site catalyst comprises the following steps:
s3-1, by mass ratio of (8-10): 6-8) (3 to 5) and (1 to 3) weighing g-C3N4、H3BO3、Ni(NO3)2·6H2O、La(NO3)3·6H2O；
S3-2, weighing Ni (NO)3)2·6H2O、La(NO3)3·6H2O is respectively prepared to have the concentration of 0.1-0.3 mol.L-1An aqueous solution of (a); h is to be3BO3The concentration of the compound is 0.1-0.3 mol.L-1An aqueous solution of (a);
s3-3, mixing the aqueous solution prepared in the step S3-2, and then carrying out ultrasonic treatment for 30-40 min; then adding g-C3N4Then carrying out ultrasonic treatment for 30-40 min to uniformly mix the components, finally carrying out magnetic stirring for 3-5 h at the temperature of 60-70 ℃, and filtering and drying to obtain a semi-finished product of the atomic-scale active site catalyst.
More preferably, the drying temperature in the step S3-3 of the invention is 100-140 ℃, and the drying time is 3-6 h.
Preferably, the hydrogen-argon mixed atmosphere of step S4-2 of the present invention has a hydrogen content of 5 wt%.
More preferably, in step S4-2 of the present invention, the flow rate of the hydrogen-argon mixture gas is 50 to 100mLmin-1。
Compared with the prior art, the invention has the following beneficial effects:
1) the catalyst has stable structure and unique electronic performance, and has the potential of promoting the activation of oxygen and reactant molecules for both the electron donating characteristic and the surface alkaline site, wherein the alkaline site is favorable for increasing NO and O2The amount of adsorption of (3). The loaded Ni and La active sites form rich acid sites on the surface of the catalyst, have strong oxidation-reduction property and are beneficial to the adsorption and activation of ammonia gas under the condition of normal temperature;
2) the catalyst of the invention greatly improves the catalytic activity and the stability of the catalyst through the interaction between metals and the coordination environment formed by Ni, La and the carrier. With graphite-like phase carbon nitride (g-C)3N4) Is a carrier, loads evenly dispersed atomic-level active sites, and introduces transition metals and rare earth metals to form the catalyst compared with the traditional SCR denitrationThe normal-temperature denitration effect is realized by the bimetallic atomic-level concerted catalysis;
3) the preparation method of the catalyst has the advantages of simple operation, excellent performance and low metal load, greatly improves the utilization efficiency of metal atoms, reduces the cost, and adopts the catalyst NH at normal temperature3Higher N in the SCR reaction2Selectivity, high efficiency and stability, and has wide application prospect in industrial application.
Drawings
FIG. 1 is a STEM diagram of the finished product of the atomic-scale active site catalyst prepared in example 1 of the present invention.
Detailed Description
The present invention will be further illustrated by the following examples
Example 1
For normal temperature NH3The preparation method of the atomic-scale active site catalyst for SCR denitration comprises the following steps:
1) first of all, g-C3N4Carrier
Accurately weighing 10g of melamine, placing the melamine into a covered crucible, placing the crucible into a muffle furnace, calcining the melamine at 550 ℃ for 3 hours, and raising the temperature for 5 ℃ min-1(warming from 30 ℃ to 550 ℃ taking 104 min); after it is naturally cooled to room temperature, the block sample is removed and ground to a uniform powder, g-C3N4And (3) a carrier.
2) Take 0.92g g-C3N4、0.618g H3BO3、0.2908g Ni(NO3)2·6H2O、0.2165gLa(NO3)3Grinding, mixing, placing in a muffle furnace, calcining at 500 deg.C for 3 hr at a heating rate of 5 deg.C for min-1(the temperature is increased from 30 ℃ to 500 ℃ and the time is 94min), and an atomic-scale active site catalyst semi-finished product is obtained;
3) calcining the semi-finished product of the atomic-scale active site catalyst in a tubular furnace, wherein the nitrogen flow rate is 100mLmin-1The calcination temperature is 800 ℃, and the calcination time is 3 h;
4) finally, the mixture is put in a hydrogen-argon mixed atmosphere (wherein the hydrogen accounts for 5wt percent) and the temperature is 500 DEG CReducing for 3h under the condition of a mixed gas flow rate of 100mLmin-1And obtaining the finished product of the atomic-level active site catalyst.
And (3) testing the activity of the catalyst: fixing 3g of catalyst powder sample in a flue gas simulation reaction device, and simulating the flue gas to pass through NO and NH3、O2、N2Prepared by mixing the mixed gas with the composition of 600ppm NO and 600ppm NH3，3.5％O2，N2The space velocity is 6000h for balance gas-1And when the reaction temperature is 25 ℃, the denitration efficiency reaches 94.7 percent.
Example 2
For normal temperature NH3The preparation method of the atomic-scale active site catalyst for SCR denitration comprises the following steps:
1) first of all, g-C3N4Carrier
Accurately weighing 10g of melamine, placing the melamine into a covered crucible, placing the crucible into a muffle furnace, calcining the melamine at 580 ℃ for 4 hours, and raising the temperature for 7 ℃ for min-1(warming from 30 ℃ to 550 ℃ taking 79 min); after it is naturally cooled to room temperature, the block sample is removed and ground to a uniform powder, g-C3N4A carrier;
2) weighing 0.92g g-C3N4、0.618g H3BO3、0.2908g Ni(NO3)2·6H2O、0.2165gLa(NO3)3Grinding, mixing, calcining in a muffle furnace at 600 deg.C for 4 hr at a heating rate of 7 deg.C for min-1(the temperature is increased from 30 ℃ to 600 ℃, and the time is taken for 82min), and a semi-finished product of the atomic-scale active site catalyst is obtained;
3) calcining the semi-finished product of the atomic-scale active site catalyst in a tubular furnace, wherein the nitrogen flow rate is 200mLmin-1The calcination temperature is 900 ℃, and the calcination time is 3 h;
4) finally, reduction is carried out for 4h under the conditions of hydrogen-argon mixed atmosphere (wherein the hydrogen content is 5wt percent) and the temperature is 550 ℃, wherein the flow rate of the mixed gas is 100mLmin-1And obtaining the finished product of the atomic-level active site catalyst.
CatalysisTesting of the activity of the agent: fixing 3g of catalyst powder sample in a flue gas simulation reaction device, and simulating the flue gas to pass through NO and NH3、O2、N2Prepared by mixing the mixed gas with the composition of 600ppm NO and 600ppm NH3，3.5％O2，N2The space velocity is 6000h for balance gas-1And when the reaction temperature is 25 ℃, the denitration efficiency reaches 93.6 percent.
Example 3
For normal temperature NH3The preparation method of the atomic-scale active site catalyst for SCR denitration comprises the following steps:
1) first of all, g-C3N4Carrier
Accurately weighing 10g of melamine, placing the melamine into a covered crucible, placing the crucible into a muffle furnace, calcining the melamine at 550 ℃ for 3 hours, and raising the temperature for 5 ℃ min-1(warming from 30 ℃ to 550 ℃ taking 104 min); after it is naturally cooled to room temperature, the block sample is removed and ground to a uniform powder, g-C3N4A carrier;
2) weighing 0.92g g-C3N4、0.618g H3BO3、0.2908g Ni(NO3)2·6H2O、0.2165gLa(NO3)3Then adding 50mL of ethanol and 50mL of deionized water, and carrying out ultrasonic treatment in an ultrasonic instrument for 1h, wherein the ultrasonic frequency is 40 kHz; after ultrasonic treatment, carrying out magnetic stirring for 3 hours at the temperature of 60 ℃, and then carrying out magnetic stirring for 3 hours at the temperature of 85 ℃; finally, drying the catalyst for 3 hours at the temperature of 100 ℃, and grinding the catalyst uniformly to obtain a semi-finished product of the atomic-scale active site catalyst;
3) calcining the semi-finished product of the atomic-scale active site catalyst in a tubular furnace, wherein the nitrogen flow rate is 100mLmin-1The calcination temperature is 800 ℃, and the calcination time is 3 h;
4) finally, reduction is carried out for 3h under the conditions of hydrogen-argon mixed atmosphere (wherein the hydrogen accounts for 5 wt%) and the temperature is 500 ℃, wherein the flow rate of the mixed gas is 100mLmin-1And obtaining the finished product of the atomic-level active site catalyst.
And (3) testing the activity of the catalyst: fixing a 3g sample of catalyst powder to the flue gas simulationIn the device, the simulated smoke passes through NO and NH3、O2、N2Prepared by mixing the mixed gas with the composition of 600ppm NO and 600ppm NH3，3.5％O2，N2The space velocity is 6000h for balance gas-1And when the reaction temperature is 25 ℃, the denitration efficiency reaches 95.2 percent.
Example 4
For normal temperature NH3The preparation method of the atomic-scale active site catalyst for SCR denitration comprises the following steps:
1) first of all, g-C3N4Carrier
Accurately weighing 10g of melamine, placing the melamine into a covered crucible, placing the crucible into a muffle furnace, calcining the melamine at 580 ℃ for 4 hours, and raising the temperature for 7 ℃ for min-1(increasing the temperature from 30 ℃ to 580 ℃ and taking 79 min); after it is naturally cooled to room temperature, the block sample is removed and ground to a uniform powder, g-C3N4A carrier;
2) weighing 0.92g g-C3N4、0.618g H3BO3、0.2908g Ni(NO3)2·6H2O、0.2165gLa(NO3)3Then adding 50mL of ethanol and 50mL of deionized water, and carrying out ultrasonic treatment in an ultrasonic instrument for 2 hours, wherein the ultrasonic frequency is 40 kHz; after ultrasonic treatment, carrying out magnetic stirring for 3 hours at the temperature of 70 ℃, and then carrying out magnetic stirring for 3 hours at the temperature of 90 ℃; finally, drying for 3 hours at the temperature of 140 ℃, and grinding uniformly to obtain a semi-finished product of the atomic-scale active site catalyst;
3) calcining the semi-finished product of the atomic-scale active site catalyst in a tubular furnace, wherein the nitrogen flow rate is 200mLmin-1The calcination temperature is 900 ℃, and the calcination time is 3 h;
4) finally, reduction is carried out for 4h under the conditions of hydrogen-argon mixed atmosphere (wherein the hydrogen content is 5wt percent) and the temperature is 550 ℃, wherein the flow rate of the mixed gas is 100mLmin-1And obtaining the finished product of the atomic-level active site catalyst.
And (3) testing the activity of the catalyst: fixing 3g of catalyst powder sample in a flue gas simulation reaction device, and simulating the flue gas to pass through NO and NH3、O2、N2Prepared by mixing the mixed gas with the composition of 600ppm NO and 600ppm NH3，3.5％O2，N2The space velocity is 6000h for balance gas-1And when the reaction temperature is 25 ℃, the denitration efficiency reaches 94.2 percent.
Example 5
For normal temperature NH3The preparation method of the atomic-scale active site catalyst for SCR denitration comprises the following steps:
1) first of all, g-C3N4Carrier
Accurately weighing 10g of melamine, placing the melamine into a covered crucible, placing the crucible into a muffle furnace, calcining the melamine at 550 ℃ for 3 hours, and raising the temperature for 5 ℃ min-1(warming from 30 ℃ to 550 ℃ taking 104 min); after it is naturally cooled to room temperature, the block sample is removed and ground to a uniform powder, g-C3N4A carrier;
2) taking 1.048mL of solution with the concentration of 0.1 mol.L-1Ni (NO) of3)2·6H2O aqueous solution, 0.443mL, 0.1 mol. L concentration-1La (NO) of3)2·6H2An aqueous solution of O; and 0.618g H3BO3Dissolving in 50mL of distilled water to prepare an aqueous solution; mixing the above three aqueous solutions, performing ultrasonic treatment for 30min, and adding 0.92gg-C3N4Then the mixture is evenly mixed by ultrasonic for 30min, and then the mixture is magnetically stirred for 3h at the temperature of 60 ℃; finally, drying the obtained product in a drying oven at 100 ℃ for 3 hours, and grinding the dried product into powder to obtain a semi-finished product of the atomic-scale active site catalyst;
3) calcining the semi-finished product of the atomic-scale active site catalyst in a tubular furnace, wherein the nitrogen flow rate is 100mLmin-1The calcination temperature is 800 ℃, and the calcination time is 3 h;
4) finally, reduction is carried out for 3h under the conditions of hydrogen-argon mixed atmosphere (wherein the hydrogen accounts for 5 wt%) and the temperature is 500 ℃, wherein the flow rate of the mixed gas is 100mLmin-1And obtaining the finished product of the atomic-level active site catalyst.
And (3) testing the activity of the catalyst: fixing 3g of catalyst powder sample in a flue gas simulation reaction device, and simulating the flue gas to pass through NO and NH3、O2、N2Prepared by mixing the mixed gas with the composition of 600ppm NO and 600ppm NH3，3.5％O2，N2The space velocity is 6000h for balance gas-1And when the reaction temperature is 25 ℃, the denitration efficiency reaches 95.7 percent.
Example 6
For normal temperature NH3The preparation method of the atomic-scale active site catalyst for SCR denitration comprises the following steps:
1) first of all, g-C3N4Carrier
Accurately weighing 10g of melamine, placing the melamine into a covered crucible, placing the crucible into a muffle furnace, calcining the melamine at 550 ℃ for 3 hours, and raising the temperature for 7 ℃ min-1(increasing the temperature from 30 ℃ to 580 ℃ and taking 79 min); after it is naturally cooled to room temperature, the block sample is removed and ground to a uniform powder, g-C3N4A carrier;
2) taking 1.048mL of solution with the concentration of 0.1 mol.L-1Ni (NO) of3)2·6H2O aqueous solution, 0.443mL, 0.1 mol. L concentration-1La (NO) of3)2·6H2An aqueous solution of O; and 0.618g H3BO3Dissolving in 50mL of distilled water to prepare an aqueous solution; mixing the above three aqueous solutions, performing ultrasonic treatment for 40min, and adding 0.92gg-C3N4Then the mixture is evenly mixed by ultrasonic for 40min, and then the mixture is magnetically stirred for 3h at the temperature of 70 ℃; finally, drying the catalyst in a drying oven at 140 ℃ for 4 hours, and grinding the dried catalyst into powder to obtain a semi-finished product of the atomic-scale active site catalyst;
3) calcining the semi-finished product of the atomic-scale active site catalyst in a tubular furnace, wherein the nitrogen flow rate is 200mLmin-1The calcination temperature is 900 ℃, and the calcination time is 3 h;
4) finally, reduction is carried out for 4h under the conditions of hydrogen-argon mixed atmosphere (wherein the hydrogen content is 5wt percent) and the temperature is 550 ℃, wherein the flow rate of the mixed gas is 100mLmin-1And obtaining the finished product of the atomic-level active site catalyst.
And (3) testing the activity of the catalyst: fixing 3g of catalyst powder sample in a flue gas simulation reaction device, and simulating the flue gas to pass through NO and NH3、O2、N2Prepared by mixing the mixed gas with the composition of 600ppm NO and 600ppm NH3，3.5％O2，N2The space velocity is 6000h for balance gas-1And when the reaction temperature is 25 ℃, the denitration efficiency reaches 94.1%.
Comparative example 1
According to the preparation method of the embodiment 5, the roasting atmosphere in the step 4) is adjusted to Ar, and the rest processes are not changed, so that a catalyst finished product is obtained. The prepared catalyst was tested for activity using the test method of example 5, and the denitration efficiency was 72.5%.
Comparative example 2
According to the preparation method of example 5, the calcination atmosphere in step 4) was adjusted to a mixed atmosphere of hydrogen and argon having a hydrogen content of 10 wt%, and the remaining processes were not changed to obtain a catalyst product. The prepared catalyst was tested for activity using the test method of example 5, and the denitration efficiency was 84.9%.
Comparative example 3
According to the preparation method of the embodiment 5, the roasting atmosphere of the step 4) is adjusted to be air, and the rest processes are not changed, so that a catalyst finished product is obtained. The prepared catalyst was tested for activity by the test method of example 5, and the denitration efficiency was 31.2%.
As can be seen from FIG. 1 of a spherical aberration correction high angle annular dark field scanning transmission electron microscope (AC-HADDF-STEM), the active sites on the catalyst carrier of the present invention exhibit atomic scale distribution. The combination of the catalytic performance detection shows that the catalyst prepared by the method has excellent performance, has higher NO conversion rate under the normal temperature condition, and the conversion rate is over 93 percent.
The specific surface area, average pore diameter and pore volume of the catalysts prepared in example 5 and comparative examples 1 to 3 were measured, as shown in table 1.
TABLE 1 BET specific surface area, average pore diameter and pore volume of catalysts synthesized in different calcination atmospheres
Figure BDA0003035932990000081
As can be seen from Table 1, the catalyst calcined in a hydrogen-argon mixed atmosphere containing 5% by mass of hydrogen exhibits the highest catalytic activity and the good stability, and has the largest specific surface area (265.28 m)2·g-1) And pore volume (0.1947 cm)3·g-1). Generally speaking, the larger the specific surface area and pore volume of the carrier, the greater the number of active sites that can be supported, which facilitates the uniform dispersion of the metal active atoms on the carrier, while the larger specific surface area also facilitates the full contact of the catalyst with the reactant molecules, thereby positively affecting the catalytic performance. Furthermore, the average pore diameter of the catalyst prepared in a hydrogen-argon mixed atmosphere having a hydrogen mass percent purity of 5% is not the largest, which can be attributed to the fact that the larger pore diameter is not favorable for stable anchoring of Ni and La metal particles on the support, while the smaller pore diameter is liable to be clogged, not favorable for NO and NH3Adsorption and transport diffusion of molecules at the active sites results in a decrease in denitration ability. Therefore, the invention discloses NH, wherein the microstructure is adjusted by calcining in a hydrogen-argon atmosphere, and the prepared catalyst has larger specific surface area, pore volume and proper pore diameter3One of the reasons for the excellent catalytic performance exhibited in SCR denitration.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims (8)

1. For normal temperature NH3The preparation method of the atomic-level active site catalyst for SCR denitration is characterized in that the catalyst is prepared at g-C by adopting a direct calcination method, a liquid phase doping method or an impregnation method3N4Loading bimetal on a carrier to prepare a semi-finished product of the atomic-scale active site catalyst, and then calcining the semi-finished product to prepare the catalyst, wherein the bimetal is Ni and La;
the calcination treatment comprises the following steps:
s4-1, feeding the semi-finished product of the atomic-scale active site catalyst into a tube furnaceCalcining is carried out, wherein the nitrogen flow rate is 100--1The calcination temperature is 800-900 ℃, and the calcination time is 2-4 h;
s4-2, and then reducing for 3-4h under the conditions of hydrogen-argon mixed atmosphere and temperature of 500-550 ℃.
2. The method of claim 1, wherein the direct calcination process for preparing the atomically active site catalyst comprises the steps of:
s1-1, weighing g-C according to the mass ratio of (8-10) to (6-8) to (3-5) to (1-3)3N4、H3BO3、Ni(NO3)2·6H2O、La(NO3)3Grinding and mixing uniformly;
s1-2, placing the uniformly mixed raw materials into a muffle furnace, calcining for 3-5 hours at 500-600 ℃ to obtain a semi-finished product of the atomic-scale active site catalyst, and placing the muffle furnace into the muffle furnace to heat the semi-finished product at a rate of 5-7 ℃ for min-1。
3. The method for preparing the atomic-scale active site catalyst according to claim 1, wherein the liquid phase doping method for preparing the atomic-scale active site catalyst comprises the following steps:
s2-1, weighing g-C according to the mass ratio of (8-10) to (6-8) to (3-5) to (1-3)3N4、H3BO3、Ni(NO3)2·6H2O、La(NO3)3Mixing, adding ethanol and deionized water to obtain solution, and performing ultrasonic treatment for 1-3 h;
s2-2, performing ultrasonic treatment, performing magnetic stirring at the temperature of 60-70 ℃ for 3 hours, and performing magnetic stirring at the temperature of 85-90 ℃ for 3 hours; and finally, drying for 3 hours at the temperature of 100-140 ℃, and grinding uniformly to obtain a semi-finished product of the atomic-level active site catalyst.
4. The method according to claim 3, wherein the volume ratio of the ethanol to the deionized water in step S2-1 is 1: 1.
5. The method of claim 1, wherein the impregnation method for preparing the atomic-scale active site catalyst comprises the steps of:
s3-1, weighing g-C according to the mass ratio of (8-10) to (6-8) to (3-5) to (1-3)3N4、H3BO3、Ni(NO3)2·6H2O、La(NO3)3·6H2O；
S3-2, weighing Ni (NO)3)2·6H2O、La(NO3)3·6H2O is respectively prepared to have the concentration of 0.1-0.3 mol.L-1An aqueous solution of (a); h is to be3BO3The concentration of the compound is 0.1-0.3 mol.L-1An aqueous solution of (a);
s3-3, mixing the aqueous solution prepared in the step S3-2, and then carrying out ultrasonic treatment for 30-40 min; then adding g-C3N4Then carrying out ultrasonic treatment for 30-40 min to uniformly mix the components, finally carrying out magnetic stirring for 3-5 h at the temperature of 60-70 ℃, and filtering and drying to obtain a semi-finished product of the atomic-scale active site catalyst.
6. The preparation method according to claim 5, wherein the drying temperature in step S3-3 is 100-140 ℃ and the drying time is 3-6 h.
7. The method according to claim 1, wherein the hydrogen-argon mixed atmosphere of step S4-2 contains 5 wt% of hydrogen.
8. The method according to claim 7, wherein the flow rate of the hydrogen-argon mixture gas in step S4-2 is 50-100 mL min-1。
CN202110443261.0A 2021-04-23 2021-04-23 For normal temperature NH3Preparation method of-SCR denitration atomic-level active site catalyst Withdrawn CN113117722A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110443261.0A CN113117722A (en) 2021-04-23 2021-04-23 For normal temperature NH3Preparation method of-SCR denitration atomic-level active site catalyst

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110443261.0A CN113117722A (en) 2021-04-23 2021-04-23 For normal temperature NH3Preparation method of-SCR denitration atomic-level active site catalyst

Publications (1)

Publication Number Publication Date
CN113117722A true CN113117722A (en) 2021-07-16

Family

ID=76779677

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110443261.0A Withdrawn CN113117722A (en) 2021-04-23 2021-04-23 For normal temperature NH3Preparation method of-SCR denitration atomic-level active site catalyst

Country Status (1)

Country Link
CN (1) CN113117722A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113413904A (en) * 2021-07-30 2021-09-21 安徽元琛环保科技股份有限公司 g-C3N4Low-temperature NH of loaded manganese cerium composite oxide3-SCR catalyst, preparation method and application thereof
CN113877618A (en) * 2021-09-28 2022-01-04 安徽元琛环保科技股份有限公司 Preparation method of oxygen-doped graphite-phase carbon nitride-loaded manganese-based low-temperature denitration catalyst and prepared denitration catalyst
CN114192176A (en) * 2021-12-29 2022-03-18 安徽元琛环保科技股份有限公司 Carbon-doped graphite-phase carbon nitride-loaded iron-manganese denitration catalyst and preparation method and application thereof
CN115463683A (en) * 2022-10-31 2022-12-13 山东华源特新材料科技有限公司 Efficient denitration catalyst and preparation method thereof
CN115779887A (en) * 2022-11-02 2023-03-14 北京建筑材料科学研究总院有限公司 Vanadium-based denitration catalyst based on rapid SCR reaction and preparation and application thereof

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113413904A (en) * 2021-07-30 2021-09-21 安徽元琛环保科技股份有限公司 g-C3N4Low-temperature NH of loaded manganese cerium composite oxide3-SCR catalyst, preparation method and application thereof
CN113877618A (en) * 2021-09-28 2022-01-04 安徽元琛环保科技股份有限公司 Preparation method of oxygen-doped graphite-phase carbon nitride-loaded manganese-based low-temperature denitration catalyst and prepared denitration catalyst
CN113877618B (en) * 2021-09-28 2024-01-23 安徽元琛环保科技股份有限公司 Preparation method of oxygen-doped graphite-phase carbon nitride-supported manganese-based low-temperature denitration catalyst and prepared denitration catalyst
CN114192176A (en) * 2021-12-29 2022-03-18 安徽元琛环保科技股份有限公司 Carbon-doped graphite-phase carbon nitride-loaded iron-manganese denitration catalyst and preparation method and application thereof
CN114192176B (en) * 2021-12-29 2023-11-10 安徽元琛环保科技股份有限公司 Carbon-doped graphite-phase carbon nitride-loaded iron-manganese denitration catalyst and preparation method and application thereof
CN115463683A (en) * 2022-10-31 2022-12-13 山东华源特新材料科技有限公司 Efficient denitration catalyst and preparation method thereof
CN115463683B (en) * 2022-10-31 2023-02-24 山东华源特新材料科技有限公司 Efficient denitration catalyst and preparation method thereof
CN115779887A (en) * 2022-11-02 2023-03-14 北京建筑材料科学研究总院有限公司 Vanadium-based denitration catalyst based on rapid SCR reaction and preparation and application thereof
CN115779887B (en) * 2022-11-02 2024-04-30 北京建筑材料科学研究总院有限公司 Vanadium-based denitration catalyst based on rapid SCR (selective catalytic reduction) reaction, and preparation and application thereof

Similar Documents

Publication Publication Date Title
CN113117722A (en) For normal temperature NH3Preparation method of-SCR denitration atomic-level active site catalyst
CN110180570B (en) Cobaltosic oxide dodecahedron/carbon nitride nanosheet compound and application thereof in waste gas treatment
CN107362807B (en) Mn/Co-based low-temperature SCO catalyst and preparation method thereof
CN110508309B (en) Carbon nitride supported chromium oxide catalyst and preparation method and application thereof
CN108744953B (en) Application method of OMS-2 and/or metal-doped OMS-2 catalytic flue gas denitration
CN112138702B (en) Three-dimensional/two-dimensional Ni-Co bimetallic oxide/g-C3N4Nano composite material and preparation method and application thereof
CN110639548B (en) Monoatomic palladium-cobalt bimetallic nano-catalyst for efficiently catalyzing benzene oxidation
CN108772067B (en) Preparation method of loaded double-transition metal monoatomic ACF catalyst for degrading VOCs at normal temperature
CN109772465B (en) Preparation method of water-soluble carbon dot modified perovskite type catalytic material
CN104607240A (en) Bi/g-C3N4 semimetal-organic composite photocatalyst and preparation method
CN108435189B (en) Samarium-doped iron-based denitration catalyst with water resistance and sulfur resistance and preparation method thereof
CN107376908B (en) A kind of indium doping ordered mesoporous aluminium oxide loaded noble metal catalyst and its application
CN113649022B (en) Catalyst for catalytic combustion of organic volatile waste gas and preparation method thereof
CN106732581A (en) A kind of Ru/CeTiO for low-temperature SCR reactionXThe preparation method of catalyst
CN108889301B (en) Spinel type catalyst and preparation method thereof
CN105597769A (en) Preparing method for flake-feature nano-composite metal oxide catalyst CeO2-Co3O4
CN111905718A (en) Method for preparing perovskite type methane combustion catalyst with assistance of plasma
CN113181902A (en) Preparation method and application of trimanganese tetroxide catalyst rich in metal defects
CN113877611B (en) Phosphoric acid modified manganese oxide supported catalyst and preparation method thereof
CN108554416A (en) A kind of modified cobalt-base catalyst and the preparation method and application thereof
CN111135834A (en) LaNixCo1-xO3Photo-thermal synergistic degradation toluene of La perovskite
CN108579756B (en) Laminaria-shaped Mn-Fe bimetal oxide loaded CeO2Catalyst, preparation method and application
Wang et al. Selective catalytic reduction of NO by CO over MOF-based CuOx@ ZIF-67 catalysts and reaction mechanism
CN108514881A (en) One kind being used for NH3Cu-Ce catalyst, preparation method and the application of the nano bar-shape structure of catalysis oxidation
CN110329992B (en) Catalyst for preparing hydrogen by reforming methanol with low temperature water vapor and preparation method thereof

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
WW01 Invention patent application withdrawn after publication
WW01 Invention patent application withdrawn after publication

Application publication date: 20210716