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CN-121988313-A - Monoatomic nanometer island NH3SCR catalyst, method for the production and use thereof

CN121988313ACN 121988313 ACN121988313 ACN 121988313ACN-121988313-A

Abstract

The application discloses a single-atom nano island NH 3 -SCR catalyst, a preparation method and application thereof, and particularly relates to the field of catalyst preparation. The preparation method comprises the steps of dispersing layered metalloate nanotubes in deionized water, sequentially adding aqueous solution of cerium precursor salt and alkali solution to the layered metalloate nanotubes to enable Ce (OH) 3 nanometer islands to be deposited on the surfaces of the layered metalloate nanotubes to obtain a first reactant, dispersing the first reactant in the deionized water, adding mixed solution of various oxidative metalloates to the first reactant to enable multicomponent metal monoatoms to be deposited on the surfaces of the Ce (OH) 3 nanometer islands to obtain a second reactant, and carrying out heat treatment on the second reactant to obtain the catalyst. By the method, multi-component monoatomic sites can be limited on the surfaces of nano-sized CeO 2 particles, so that a synergistic catalytic effect is generated among monoatoms.

Inventors

  • MEI HUI
  • Wei Feibin
  • YANG YIQUAN
  • HUANG YU
  • LAI MIAO
  • WANG WEI
  • LIU YAN

Assignees

  • 西北工业大学
  • 西安泽坤环能新材料科技有限公司
  • 中国科学院地球环境研究所

Dates

Publication Date
20260508
Application Date
20260310

Claims (10)

  1. 1. The preparation method of the monoatomic nanometer island NH 3 -SCR catalyst is characterized by comprising the following steps of: dispersing layered metalloate nanotubes in deionized water, and sequentially adding aqueous solution of cerium precursor salt and alkali solution to the layered metalloate nanotubes to enable Ce (OH) 3 nanometer islands to be deposited on the surfaces of the layered metalloate nanotubes, so as to obtain a first reactant; Dispersing the first reactant in deionized water, and adding a mixed solution of a plurality of oxidative metal acid salts to the first reactant to enable multi-component metal monoatoms to be deposited on the surface of a Ce (OH) 3 nanometer island, so as to obtain a second reactant; Performing heat treatment on the second reactant to obtain an M/CeO 2 /LNTs catalyst; wherein the temperature of the heat treatment is 350-500 ℃ and the time is 2-5 h.
  2. 2. The method for preparing the single-atom nano-island NH 3 -SCR catalyst according to claim 1, wherein the layered metallate nanotube is H 2 Ti 3 O 7 titanate nanotube, tiO 2 nanotube, sodium titanate nanotube, lithium titanate nanotube, tungstate nanotube, molybdate nanotube or halloysite nanotube; The cerium precursor salt comprises one or a combination of more of cerium nitrate, cerium chloride, cerium sulfate and cerium oxalate.
  3. 3. The method for preparing the single-atom nano-island NH 3 -SCR catalyst according to claim 1, wherein the mass ratio of cerium to layered metallate nanotubes in the cerium precursor salt is 1:2-2.5; the molar ratio of cerium in the alkali solution to cerium precursor salt is 1:0.1-0.2.
  4. 4. The method for preparing a monoatomic nano-island NH 3 -SCR catalyst according to claim 1, wherein the ratio of the total moles of metallate ions in the oxidizing metallate solution to the moles of cerium in the cerium precursor salt is 1:0.14-0.42.
  5. 5. The method for preparing the monoatomic nano island NH 3 -SCR catalyst according to claim 1, wherein the mixed solution of the oxidative metal acid salts is a mixed solution of at least two of the oxidative metal acid salts containing Mn, mo, cr or Pt.
  6. 6. The method for preparing the monoatomic nano island NH 3 -SCR catalyst according to claim 1, wherein the alkali solution is one or a combination of a plurality of ammonia water, sodium hydroxide aqueous solution and potassium hydroxide aqueous solution.
  7. 7. The method of preparing a monoatomic nano-island NH 3 -SCR catalyst according to claim 1, wherein before dispersing the layered metalloate nanotubes in deionized water, the method further comprises, Washing the layered metalloate nanotube by using pickling solution until the pH value of the solution is 0.8-1.2, and washing the layered metalloate nanotube by using deionized water until the pH value of the solution is 6-7 to obtain a precipitate; the precipitate is dispersed in an organic solvent and dried at 80-90 ℃.
  8. 8. The preparation method of the single-atom nano island NH 3 -SCR catalyst according to claim 7, wherein the pickling solution is one or a combination of more of hydrochloric acid, nitric acid and oxalic acid, the concentration of hydrogen ions in the solution is 0.1-0.2mol/L, and the organic solvent is one or a combination of more of methanol, ethanol, propanol, isopropanol and butanol.
  9. 9. A monatomic nano island NH 3 -SCR catalyst, characterized in that it is obtained by the method for preparing a monatomic nano island NH 3 -SCR catalyst according to any one of claims 1-8.
  10. 10. Use of the monoatomic nano island NH 3 -SCR catalyst of claim 9 to catalyze NH 3 -SCR reaction under low temperature aqueous sulfur conditions.

Description

Monoatomic nanometer island NH 3 -SCR catalyst and preparation method and application thereof Technical Field The application relates to the field of catalyst preparation, in particular to a single-atom nano island NH 3 -SCR catalyst, a preparation method and application thereof. Background Nitrogen oxides (NO x) are the main atmospheric pollutants, and are also key precursors for ozone and PM2.5 formation, with great harm to the atmospheric environment and human health. Under the trend of continuous expansion of the non-thermal power industry scale, effective control of the NO x content in low-temperature (less than or equal to 180 ℃) flue gas has become an urgent challenge for current industrial pollution control. Ammonia selective catalytic reduction (NH 3 -SCR) is the most widely used technique for industrial NO x removal, but conventional V 2O5-WO3(MoO3)/TiO2 catalysts are limited by their narrow operating temperature window (300-450 ℃) and cannot be directly applied at low temperatures, often requiring a large amount of energy to heat the flue gas to the desired temperature. In addition, when the temperature is lower than 300 ℃, SO 2 and water existing in the flue gas can react to generate sulfate which is attached to the surface of the catalyst, SO that the catalyst is seriously and irreversibly poisoned and deactivated, and the service life of the catalyst is influenced. Therefore, the development of an NH 3 -SCR catalyst which has high denitration efficiency at low temperature and good water resistance and sulfur resistance is important to the NO x control of flue gas in non-thermal power industry. The single-atom metal catalyst has uniformly dispersed active sites and high atom utilization rate, and is expected to realize low-temperature NH 3 -SCR catalytic conversion. However, the NH 3 -SCR reaction is complex in steps, the types of intermediate products are many, and the catalyst surface is required to provide multi-component monoatomic sites with synergistic effect so as to meet the reaction requirements. In the prior art, although attempts are made to integrate single atoms of different components into the same catalyst structure to realize the requirement, the distance between single atom sites cannot be controlled in the synthesis method, so that a synergistic catalysis effect is difficult to generate between single atoms with a larger distance, and the problem of agglomeration of the single atoms at a high temperature cannot be avoided in the prior art. Disclosure of Invention The application mainly aims to provide a monoatomic nanometer island NH 3 -SCR catalyst, a preparation method and application thereof, and aims to solve the problems that multi-component monoatomic sites are difficult to integrate in the same structure and the interatomic distance is effectively limited in the existing preparation method. The application provides a preparation method of a single-atom nanometer island NH 3 -SCR catalyst, which comprises the steps of dispersing layered metal acid salt nanometer tubes in deionized water, sequentially adding aqueous solution of cerium precursor salt and alkali solution into the layered metal acid salt nanometer tubes to enable Ce (OH) 3 nanometer islands to be deposited on the surfaces of the layered metal acid salt nanometer tubes to obtain a first reactant, dispersing the first reactant in the deionized water, adding mixed solution of various oxidative metal acid salts into the first reactant to enable multi-component metal single atoms to be deposited on the surfaces of Ce (OH) 3 nanometer islands to obtain a second reactant, and carrying out heat treatment on the second reactant to obtain the M/CeO 2/LNTs catalyst, wherein the heat treatment temperature is 350-500 ℃ and the time is 2-5 h. Optionally, the layered metallate nanotube is H 2Ti3O7 titanate nanotube, tiO 2 nanotube, sodium titanate nanotube, lithium titanate nanotube, tungstate nanotube, molybdate nanotube or halloysite nanotube, and the cerium precursor salt comprises one or more of cerium nitrate, cerium chloride, cerium sulfate and cerium oxalate. Optionally, the mass ratio of cerium in the cerium precursor salt to the layered metallate nanotubes is 1:2-2.5, and the molar ratio of the alkali solution to cerium in the cerium precursor salt is 1:0.1-0.2. Alternatively, the ratio of the total moles of metallate ions in the oxidizing metallate solution to the moles of cerium in the cerium precursor salt is 1:0.14 to 0.42. Alternatively, the mixed solution of the oxidizing metal acid salts is a mixed solution of at least two of the oxidizing metal acid salts containing Mn, mo, cr, or Pt. Optionally, the alkali solution is one or more of ammonia water, sodium hydroxide aqueous solution and potassium hydroxide aqueous solution. Optionally, before dispersing the layered metalloate nanotubes in deionized water, the method further comprises washing the layered metalloate nanotubes with an acid wash until the pH of