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CN-122006717-A - For decomposing N2O-based CuO composite oxide catalyst and preparation method thereof

CN122006717ACN 122006717 ACN122006717 ACN 122006717ACN-122006717-A

Abstract

The invention discloses a CuO-based composite oxide catalyst for decomposing N 2 O and a preparation method thereof, belonging to the technical field of chemical catalysis. The catalyst comprises active components of CuO, auxiliary alkali metal oxide and ZrO 2 . The preparation method comprises dissolving a certain amount of gelatinizer and soluble zirconium salt in deionized water, placing into a water bath, stirring, heating, evaporating to gel, and drying. The dried product is mixed with a quantity of soluble copper salt and grinding is continued to powder form. Transferring the powder mixture into a beaker, adding a proper amount of deionized water and alkali metal salt, putting into an ultrasonic instrument for ultrasonic treatment, and then drying, grinding, roasting and forming to obtain the catalyst. The prepared catalyst can realize direct catalytic decomposition of N 2 O at a lower temperature, has excellent performances of resisting O 2 , NO 2 and H 2 O, has higher crushing strength, and can be well applied to emission reduction of N 2 O in industrial tail gas of nitric acid production.

Inventors

  • WANG YONGZHAO
  • ZHENG KE
  • ZHU GUANGYUN
  • LI RUIFEN
  • LU JIANJIAN
  • WU RUIFANG
  • Xun Zhendong
  • GUO XIAOHUI
  • ZHANG CHENGMING
  • ZHANG LIANGLIANG

Assignees

  • 山西大学
  • 山西东锦肥业有限公司
  • 山西金兰化工股份有限公司

Dates

Publication Date
20260512
Application Date
20260126

Claims (10)

  1. 1. A CuO-based composite oxide catalyst for decomposing N 2 O is characterized by comprising an active component CuO, an auxiliary agent ZrO 2 and an alkali metal oxide.
  2. 2. The CuO-based composite oxide catalyst for decomposing N 2 O according to claim 1, wherein the content of CuO as the active component is 53.3wt% to 86.4wt%, the content of ZrO 2 as the auxiliary is 13.3wt% to 41.1wt%, and the content of alkali metal oxide as the auxiliary is 0.3wt% to 5.6wt%; and/or the auxiliary alkali metal oxide is at least one of Na 2 O、K 2 O、Cs 2 O.
  3. 3. A method for preparing the catalyst for decomposing N 2 O according to any one of claims 1 to 2, characterized by comprising the steps of: step 1, dissolving soluble salt of zirconium and a gelatinizing agent in deionized water to obtain a mixed solution; step 2, stirring the mixed solution in a water bath or an oil bath to obtain viscous gel; Step 3, mixing the dried viscous gel with soluble copper salt to obtain a mixture; step 4, grinding the mixture, adding alkali metal salt and deionized water, and carrying out ultrasonic treatment; And 5, drying, grinding, roasting and forming to obtain the catalyst for decomposing N 2 O.
  4. 4. A process for preparing a catalyst for decomposing N 2 O according to claim 3, The soluble salt of zirconium is at least one of zirconium nitrate or zirconyl nitrate; The gelatinizer is at least one of glucose, sucrose, oxalic acid and citric acid.
  5. 5. A process for preparing a catalyst for decomposing N 2 O according to claim 3, The mol ratio of the soluble salt of zirconium to the gelling agent is 1:2-10; in the mixed solution, the molar ratio of the gelling agent to the deionized water is 1:15-30.
  6. 6. A process for preparing a catalyst for decomposing N 2 O according to claim 3, The temperature of the water bath or the oil bath in the step 2 is 60-100 ℃, the stirring time is 2-8 h, and/or the stirring speed is 100 r-800 r/min.
  7. 7. A process for preparing a catalyst for decomposing N 2 O according to claim 3, The soluble copper salt in the step 3 is at least one of copper nitrate, copper chloride, copper sulfate, copper oxalate and copper acetate; The alkali metal salt is at least one of carbonate and nitrate.
  8. 8. A process for preparing a catalyst for decomposing N 2 O according to claim 3, The mole ratio of the soluble copper salt to the soluble alkali metal salt to the soluble salt of zirconium is 1:0.005-0.06:0.1-0.5; The molar ratio of the alkali metal salt to the deionized water is 1:500-1500.
  9. 9. A process for preparing a catalyst for decomposing N 2 O according to claim 3, The drying temperature in the step 3 and the step 5 is 60-130 ℃ and the drying time is 12-24 hours; and (3) the ultrasonic time in the step (4) is 0.5-2 h.
  10. 10. The method for preparing a catalyst for decomposing N 2 O according to claim 3, wherein the roasting temperature in the step 5 is 400-600 ℃, the roasting time is 2-6 hours, and the roasting atmosphere is at least one of air and nitrogen.

Description

CuO-based composite oxide catalyst for decomposing N 2 O and preparation method thereof Technical Field The invention belongs to the technical field of chemical catalysis, and particularly relates to a CuO-based composite oxide catalyst for decomposing N 2 O and a preparation method thereof. Background With the increasing global warming problem, the emission of nitrous oxide (N 2 O) has received a great deal of attention. N 2 O has a Global Warming Potential (GWP) of about 265 times that of CO 2, which is the third largest greenhouse gas following CO 2 and CH 4. At the same time, N 2 O also has a great damaging effect on the ozone layer. Particularly, with the rapid development of the modern industry, the emission amount of N 2 O is remarkably increased in the last ten years, and the emission reduction of N 2 O is not slow. The artificial emission of N 2 O is mainly focused on the production of nitric acid and adipic acid, the combustion of fossil fuels and the like. The method integrates various emission reduction technologies, directly decomposes the catalytic N 2 O into N 2 and O 2, has the advantages of simplicity, economy, high removal efficiency, no secondary pollution and the like, is the most promising method for eliminating N 2 O, and is of particular interest in the field of environmental catalysis. For direct catalytic decomposition of N 2 O, noble metal catalysts (including Rh, ir, pd, pt, ru, ag and the like) have relatively high catalytic activity at lower temperatures, have been widely studied in catalytic decomposition of N 2 O, but are expensive and unsuitable for large-scale industrial application. Zeolite molecular sieve catalysts are attractive because of their high catalytic activity, satisfactory thermal stability and low cost, but their synthesis is relatively complex and relatively poor in hydrothermal stability, limiting their application in this field. transition metal oxide catalysts are receiving increasing attention for their excellent redox properties, higher catalytic performance and relatively low cost of preparation. Ohnishi et al found a catalytic N 2 O decomposition activity sequence of NiO≡Co 3O4 > CuO in feed gas containing N 2 O and O 2 (CATALYSIS TODAY, 2007, 120, 145-150). this is consistent with the order of catalytic N 2 O decomposition activity obtained by Ma et al in the absence of O 2 (Nanotechnology, 2013, 13, 5093-5103). Among various oxide catalysts, the Co 3O4 -based catalyst shows relatively high N 2 O decomposition activity at low temperature, but the cost of cobalt gradually increases to prevent popularization and application. Therefore, cuO as a substitute is favored by researchers because of its low cost and availability. Although the CuO-based catalyst has potential application prospect in the field of N 2 O direct catalytic decomposition, the development and application path of the CuO-based catalyst are full of great difficulty and challenge. By doping alkali metal (CATALYSIS SCIENCE & Technology, 2018, 8, 2312-2322) and alkaline earth metal (Journal of Environmental CHEMICAL ENGINEERING, 2023, 11, 109970), the catalytic reaction temperature of the CuO-based catalyst can be reduced, but the complete decomposition temperature of the catalytic N 2 O is still up to 500 ℃, so that the requirements on the grade of industrial equipment are high, the impurity gas resistance is poor, and a significant gap exists between the catalytic reaction temperature and the actual industrial requirements. It is a challenge to make CuO-based catalysts having excellent catalytic activity, good stability and excellent resistance to impurity gases at the same time. Therefore, a more efficient CuO-based catalytic system is constructed, the simple preparation process is realized, the actual industrial requirement is met, and the method has great significance for promoting the industrial application of N 2 O direct catalytic decomposition technology and helping hand to realize the national 'double carbon' strategic target. Disclosure of Invention Aiming at the technical problems, the invention provides the CuO-based composite oxide catalyst with high activity, stability and impurity gas resistance and the preparation method thereof, which improve the catalytic efficiency and meet the urgent requirements of industrial tail gas from nitric acid production on low-temperature catalytic N 2 O decomposition technology. In order to solve the technical problems, the invention adopts the following technical scheme: In a first aspect, the invention provides a CuO-based composite oxide catalyst for decomposing N 2 O, wherein the catalyst comprises an active component CuO, an auxiliary agent ZrO 2 and an alkali metal oxide. Further, the content of the active component CuO is 53.3-86.4 wt%, the content of the auxiliary agent ZrO 2 is 13.3-41.1 wt%, and the content of the auxiliary agent alkali metal oxide is 0.3-5.6 wt%; and/or the auxiliary alkali metal oxide is at least on