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CN-121972172-A - For synergistic elimination of NO and N2Lanthanide metal doped Co of O3O4Catalyst, preparation method and application thereof

CN121972172ACN 121972172 ACN121972172 ACN 121972172ACN-121972172-A

Abstract

The invention belongs to the technical field of environmental catalytic materials, and in particular relates to a lanthanide metal doped Co 3 O 4 catalyst for synergistically eliminating NO and N 2 O, and a preparation method and application thereof, wherein the preparation method comprises (1) dissolving lanthanide metal salt and cobalt salt in water to obtain a mixed salt solution; the preparation method comprises the steps of (1) dissolving soluble carbonate or bicarbonate in water to obtain a precipitant solution, (3) stirring the precipitant solution, adding the precipitant solution into a mixed salt solution to enable the pH value of a reaction system to be 9-11, stirring the solution while adding the solution to obtain coprecipitation slurry, (4) carrying out hydrothermal reaction on the coprecipitation slurry prepared in the step (3) to obtain a hydrothermal product, and (5) cooling the hydrothermal product, washing, drying, grinding, calcining, and naturally cooling to room temperature to obtain the lanthanide metal doped Co 3 O 4 catalyst. According to the invention, the electronic structure of the cobalt-based catalyst is regulated and controlled by doping lanthanide metal, and the lattice distortion and surface isolation effect are introduced, so that the catalytic performance of the catalyst is effectively improved.

Inventors

  • CHEN BIAOHUA
  • ZHANG HUANJIE
  • XU RUINIAN

Assignees

  • 北京工业大学

Dates

Publication Date
20260505
Application Date
20260115

Claims (10)

  1. 1. The preparation method of the lanthanide metal doped Co 3 O 4 catalyst for cooperatively eliminating NO and N 2 O is characterized by comprising the following steps: (1) Dissolving lanthanide metal salt and cobalt salt in water to obtain mixed salt solution; (2) Dissolving soluble carbonate or bicarbonate in water to obtain a precipitant solution; (3) Adding the precipitant solution prepared in the step (2) into the mixed salt solution prepared in the step (1) at the temperature of 30-50 ℃ to enable the pH value of a reaction system to be 9-11, and stirring while adding to obtain coprecipitation slurry; (4) Placing the coprecipitation slurry prepared in the step (3) into a reaction kettle, and stirring and reacting for 2-4 hours at 180-220 ℃ to obtain a hydrothermal product; (5) And (3) cooling the hydrothermal product prepared in the step (4), washing, drying and grinding, calcining at 480-520 ℃ for 2-4 hours, and cooling to room temperature after the calcining is finished to obtain the lanthanide metal doped Co 3 O 4 catalyst.
  2. 2. The method according to claim 1, wherein the molar ratio of the lanthanide metal to cobalt in the mixed salt solution obtained in the step (1) is 0.05 to 0.2.
  3. 3. The method according to claim 2, wherein the concentration of the mixed salt solution in the step (1) is 0.5 to 1.0 mol/L, and the concentration of the precipitant solution in the step (2) is 0.4 to 0.6 mol/L.
  4. 4. The method of claim 2, wherein the lanthanide metal salt in step (1) is at least one of Sm (NO 3 ) 3 ·6H 2 O、Eu(NO 3 ) 3 ·6H 2 O).
  5. 5. The method of claim 4, wherein the cobalt salt in step (1) is one of Co (NO 3 ) 2 ·6H 2 O、CoSO 4 ·6H 2 O、CoCl 2 ·6H 2 O).
  6. 6. The method of claim 5, wherein the soluble carbonate in step (2) is at least one of Na 2 CO 3 、K 2 CO 3 and the bicarbonate is at least one of NaHCO 3 、KHCO 3 .
  7. 7. The preparation method according to claim 6, wherein the specific process of adding the precipitant solution prepared in the step (2) to the mixed salt solution prepared in the step (1) is that the precipitant solution is firstly added dropwise into the mixed salt solution at a speed of 50-75 mL/h for 0.5-1.5 h, and then the precipitant solution is added dropwise into the mixed salt solution at a speed of 95-145 mL/h for 30-40 min.
  8. 8. The preparation method of the ceramic material, according to claim 7, is characterized in that the temperature rising rate in the calcining step (5) is 2-5 ℃ per minute, the drying temperature in the step (5) is 100-120 ℃ and the drying time is 4-6 hours, and the washing process in the step (5) is to wash the ceramic material with water until the filtrate is neutral.
  9. 9. A lanthanide-doped Co 3 O 4 catalyst prepared by the method of claims 1-8.
  10. 10. Use of a lanthanide metal doped Co 3 O 4 catalyst as defined in claim 9 for the abatement of NO and/or N 2 O.

Description

Lanthanide metal-doped Co 3O4 catalyst for synergistically eliminating NO and N 2 O, and preparation method and application thereof Technical Field The invention belongs to the technical field of environmental catalytic materials, and particularly relates to a lanthanide metal doped Co 3O4 catalyst for synergistically eliminating NO and N 2 O, and a preparation method and application thereof. Background Nitrogen Oxides (NO) and nitrous oxide (N 2 O) in industrial tail gases are major atmospheric pollutants. NO is one of the precursors for the formation of photochemical smog and acid rain, while N 2 O is not only a powerful greenhouse gas but also has a damaging effect on the ozone layer. Therefore, the synergistic elimination of these two nitrogen oxides is significant for environmental protection. Currently, the technological path for the synergistic elimination of N 2 O and NO is mainly divided into one-stage and two-stage processes. The one-stage process achieves simultaneous removal in a single reaction unit, including Selective Catalytic Reduction (SCR) techniques (reduction of NO to N 2 with the help of a catalyst such as vanadium-titanium or iron molecular sieves in the presence of a reducing agent such as NH 3 and simultaneous catalytic decomposition or reduction of N 2 O) and composite catalyst techniques capable of synergistically catalyzing NO reduction and N 2 O decomposition. The two-stage process adopts a step-by-step treatment mode, and the typical flow is 'SCR denitration is followed by catalytic decomposition of N 2 O', namely, firstly, the flue gas is introduced into an SCR unit to reduce NOx into N 2, then, a specific catalyst (such as cobalt-based spinel oxide or molecular sieve catalyst) is adopted in a subsequent reactor to decompose the residual N 2 O into N 2 and O 2, and the process has the advantages of low consumption of reducing agent and high removal efficiency of N 2 O in nitric acid tail gas treatment. Nevertheless, the prior art still faces challenges of temperature window matching, insufficient capability of resisting O 2 and water vapor interference, and future research will focus on accurately regulating and controlling the electronic structure and active site of the catalyst by means of atomic scale doping (such as lanthanide metal doped Co 3O4) and the like, so as to develop novel catalytic materials and processes with higher low-temperature activity, better stability and capability of cooperatively removing various pollutants. CN106076112a discloses a method for simultaneous removal of N 2 O and NOx. The technology adopts a catalyst formed by loading noble metal (0.1-5%), transition metal oxide (3-15%) and alkali metal hydroxide (0.5-1%) on an alumina carrier, and in a temperature range of 200-600 ℃, the catalyst is used for cooperatively catalyzing the decomposition of N 2 O (N 2 and O 2 are generated) and the reduction reaction between NOx and NH 3 (N 2 is generated), so that the synchronous removal of N 2 O and NOx on a single bed layer is realized. Although the technology realizes the integrated removal of N 2 O and NOx, the main defects are that the technology relies on high-cost noble metal, introduces NH 3 with potential safety hazard, has doubtful long-term stability of the catalyst and possibly has insufficient adaptability under the condition of actual complex flue gas. These factors limit their potential for large-scale industrial application. CN105396460a discloses a method for efficiently and jointly removing N 2 O and NO x. The method comprises the steps of completely reducing NO x into N 2 by utilizing carbon materials such as coke/activated carbon at a high temperature of 500-1100 ℃ and partially decomposing N 2 O, then decomposing the residual N 2 O into N 2 and O 2 by adopting a special catalyst at a medium temperature of 200-600 ℃, and finally realizing that the total concentration of the outlet N 2 O and the NO x is lower than 100ppm. Although the process has a certain removal effect, the technology is subject to key problems of high energy consumption, material consumption, complex system, insufficient working condition adaptability and the like, and the industrial popularization faces serious challenges. CN115739172a discloses a catalyst for cooperatively removing N 2 O and NO and a preparation method thereof, which belongs to the technical field of denitrification catalysts, and takes Beta or ZSM-5 molecular sieve as a carrier to load non-noble metal active components such as Co, fe, cu and the like. The catalyst shows high activity in a wide temperature window of 400-600 ℃ and is considered to have economic and environmental protection advantages due to simple preparation and low cost. However, the technology still faces key challenges from the laboratory to industrialized application, firstly, in the actual flue gas environment, water vapor and sulfur dioxide are easy to cause hydrolysis of a molecular sieve structure or sulfur poisoning of an a