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JP-2026075569-A - Catalyst for removing nitrous oxide and method for removing nitrous oxide

JP2026075569AJP 2026075569 AJP2026075569 AJP 2026075569AJP-2026075569-A

Abstract

[Problem] To provide a catalyst for removing nitrous oxide and a method for removing nitrous oxide. [Solution] The catalyst for removing nitrous oxide comprises a metal oxide powder and an iron-copper compound. The iron-copper compound is attached to the surface of the metal oxide powder. The metal oxide powder comprises zinc oxide, magnesium oxide, aluminum oxide, or a combination thereof. The molar ratio of iron in the iron-copper compound to metal in the metal oxide powder is 1:(1.3 to 4.0). [Selection Diagram] Figure 1

Inventors

  • 張 ▲シュアン▼麟
  • 林 弘萍
  • 鄭 瑞翔
  • 李 壽南
  • 劉 思廷

Assignees

  • 財團法人工業技術研究院

Dates

Publication Date
20260508
Application Date
20250220
Priority Date
20241022

Claims (9)

  1. Metal oxide powders containing zinc oxide, magnesium oxide, aluminum oxide, or combinations thereof, The metal oxide powder contains an iron-copper compound attached to its surface, The molar ratio of iron in the iron-copper compound to metal in the metal oxide powder is 1:(1.3 to 4.0). A catalyst for removing nitrous oxide.
  2. The metal oxide powder is zinc oxide or magnesium oxide, and the catalyst further comprises an Fe₃O₄ crystal structure. The catalyst for removing nitrous oxide according to claim 1.
  3. The metal oxide powder is zinc oxide, the molar ratio of iron to copper in the iron-copper compound is 1:(1.8 to 6.2), and the molar ratio of iron in the iron-copper compound to metal in the metal oxide powder is 1:(1.4 to 4.0). The catalyst for removing nitrous oxide according to claim 1.
  4. The compound further contains aluminum, and the molar ratio of iron to aluminum in the iron-copper compound is 1:(0.1 to 0.5). The catalyst for removing nitrous oxide according to claim 3.
  5. The metal oxide powder is magnesium oxide, the molar ratio of iron to copper in the iron-copper compound is 1:(1.5 to 6.0), and the molar ratio of iron in the iron-copper compound to metal in the metal oxide powder is 1:(1.4 to 4.0). The catalyst for removing nitrous oxide according to claim 1.
  6. The metal oxide powder is aluminum oxide, the molar ratio of iron to copper in the iron-copper compound is 1:(0.2 to 2.7), and the molar ratio of iron in the iron-copper compound to metal in the metal oxide powder is 1:(1.3 to 3.6). The catalyst for removing nitrous oxide according to claim 1.
  7. The specific surface area of the catalyst is 20 m² g⁻¹ to 200 m² g⁻¹ , and the porosity of the catalyst is 60% to 90%. The catalyst for removing nitrous oxide according to claim 1.
  8. The mechanical strength of the catalyst is 0.5 kgw to 3.0 kgw. The catalyst for removing nitrous oxide according to claim 1.
  9. The method includes using the catalyst described in any one of claims 1 to 8 to decompose nitrous oxide into nitrogen ( N₂ ) and oxygen ( O₂ ), Methods for removing nitrous oxide.

Description

This invention relates to a catalyst for removing nitrous oxide and a method for removing nitrous oxide. N₂O decomposition catalysts have been studied for many years and are used in the treatment of industrial waste gases (such as semiconductor process exhaust gases containing N₂O ), as well as in the exhaust pipes of automobiles and motorcycles. However, since most of the active ingredients in the catalyst are precious metals, they are expensive and difficult to mass-produce, and they are susceptible to interference from water vapor and oxygen, which reduces catalytic activity. Furthermore, conventional processing technologies have an efficiency of only about 60% for N₂O processing, and there was a problem that processing N₂O using high-temperature pyrolysis actually generated a large amount of NOx, an air pollutant. These are the XRD spectra of the catalysts in Example 12, Comparative Example 3, and Example 1.These are the XRD spectra of the catalysts from Example 16 and Example 1.This is a schematic diagram of the equipment used to measure gas concentration and removal rate (DRE) in the experimental example.This is a curve diagram showing the N₂O removal rate and NO₂ concentration for Example 7.This is a curve diagram showing the N₂O removal rate and NO₂ concentration for Example 12.This is the catalyst lifetime curve for Example 7. The following provides various embodiments for implementing various features of the present invention. However, these embodiments are merely illustrative and are not intended to limit the scope and application of the present invention. In one embodiment of the present invention, the catalyst for removing nitrous oxide comprises a metal oxide powder and an iron-copper compound. The metal oxide powder may include zinc oxide, magnesium oxide, aluminum oxide, or a combination thereof. The iron and copper in the iron-copper compound exist, for example, in the form of iron oxide, copper oxide, or a combination thereof, respectively. The iron-copper compound may be a binary iron-copper (Fe-Cu) compound. The iron-copper compound may consist of copper oxide and iron oxide. The iron-copper compound may further be doped with other elements to improve the properties of the catalyst. For example, the iron-copper compound may be doped with an aluminum compound and may be called an aluminum-doped iron-copper compound. It mainly consists of copper oxide and iron oxide and contains a small amount of aluminum oxide to improve the mechanical properties of the catalyst. The molar ratio of iron in the iron-copper compound to the metal in the metal oxide powder may be 1:(1.3 to 4.0). For example, the metal oxide powder is zinc oxide, and the molar ratio of iron in the iron-copper compound to zinc in the zinc oxide powder is 1:(1.4 to 4.0). The metal oxide powder is magnesium oxide, and the molar ratio of iron in the iron-copper compound to magnesium in the magnesium oxide powder is 1:(1.4–4.0). The metal oxide powder is aluminum oxide, and the molar ratio of iron in the iron-copper compound to aluminum in the aluminum oxide powder is 1:(1.3–3.6). In one embodiment, the metal oxide powder is zinc oxide, and the molar ratio of iron to copper in the iron-copper compound is 1:(1.8 to 6.2). In some embodiments, the metal oxide powder is magnesium oxide, and the molar ratio of iron to copper in the iron-copper compound is 1:(1.5 to 6.0). In some embodiments, the metal oxide powder is aluminum oxide, and the molar ratio of iron to copper in the iron-copper compound is 1:(0.2 to 2.7). When the molar ratio of iron to copper is within the above range, an excellent nitrous oxide removal efficiency (DRE) can be obtained. Furthermore, X-ray diffraction analysis (XRD) revealed that when the metal oxide powder is zinc oxide or magnesium oxide, the formed catalyst exhibits a clear Fe₃O₄ diffraction peak. Therefore, it can be inferred that the catalyst may further contain the Fe₃O₄ crystal structure. In one embodiment, the catalyst for removing nitrous oxide may further contain a small amount of aluminum, for example, the molar ratio of iron in the iron-copper compound to the small amount of aluminum is 1:(0.1 to 0.5), and the aluminum is present on the surface of the metal oxide powder, for example, in the form of aluminum oxide. In one embodiment, the specific surface area of the catalyst for removing nitrous oxide is 20 m² g⁻¹ to 200 m² g⁻¹ . In one embodiment, the particle size of the catalyst for removing nitrous oxide may be 100 μm or larger, for example, about 200 μm to 5 mm, or for example, about 1 mm to 5 mm. In one embodiment, the porosity of the catalyst for removing nitrous oxide is 60% to 90%. In one embodiment, when the catalyst particles are relatively large (e.g., 1 mm or larger), the mechanical strength of the catalyst for removing nitrous oxide is 0.5 kgw to 3.0 kgw, which helps prevent damage during use that could affect the nitrous oxide treatment process. In one embodiment, the nitrous oxide r