Search

US-20260124602-A1 - ORGANIC MATTER DECOMPOSITION CATALYST, HONEYCOMB STRUCTURE, METHOD FOR DECOMPOSING ORGANIC MATTER, AND ORGANIC MATTER DECOMPOSITION DEVICE

US20260124602A1US 20260124602 A1US20260124602 A1US 20260124602A1US-20260124602-A1

Abstract

An organic matter decomposition catalyst that contains a ternary composite oxide containing zirconium, manganese, and neodymium and oxidatively decomposes organic matter. Also disclosed is a honeycomb structure, a method for decomposing organic matter, and an organic matter decomposition device that use the organic matter decomposition catalyst.

Inventors

  • Hideto Sato
  • Satoshi Kuretake
  • Soichiro Tsujimoto

Assignees

  • MURATA MANUFACTURING CO., LTD.

Dates

Publication Date
20260507
Application Date
20251230
Priority Date
20230803

Claims (18)

  1. 1 . An organic matter decomposition catalyst for oxidatively decomposing organic matter, the organic matter decomposition catalyst comprising: a ternary composite oxide containing zirconium, manganese, and neodymium.
  2. 2 . The organic matter decomposition catalyst according to claim 1 , wherein a molar ratio of manganese to zirconium in the organic matter decomposition catalyst is in a range of 0.02 to 1.00.
  3. 3 . The organic matter decomposition catalyst according to claim 1 , wherein a molar ratio of manganese to zirconium in the organic matter decomposition catalyst is in a range of 0.05 to 0.70.
  4. 4 . The organic matter decomposition catalyst according claim 2 , wherein a molar ratio of neodymium to zirconium in the organic matter decomposition catalyst is in a range of 0.002 to 0.200.
  5. 5 . The organic matter decomposition catalyst according claim 1 , wherein a molar ratio of neodymium to zirconium in the organic matter decomposition catalyst is in a range of 0.002 to 0.200.
  6. 6 . The organic matter decomposition catalyst according to claim 1 , wherein a molar ratio of neodymium to zirconium in the organic matter decomposition catalyst is in a range of 0.010 to 0.150.
  7. 7 . The organic matter decomposition catalyst according to claim 3 , wherein a molar ratio of neodymium to zirconium in the organic matter decomposition catalyst is in a range of 0.010 to 0.150.
  8. 8 . The organic matter decomposition catalyst according to claim 1 , wherein the organic matter decomposition catalyst contains a monoclinic zirconium oxide crystal phase.
  9. 9 . The organic matter decomposition catalyst according to claim 8 , wherein the monoclinic zirconium oxide crystal phase is a first crystal phase and the organic matter decomposition catalyst further contains one or more second crystal phases.
  10. 10 . The organic matter decomposition catalyst according to claim 1 , wherein in the organic matter decomposition catalyst, a molar ratio of manganese to zirconium is 0.05 or more and a molar ratio of neodymium to zirconium is 0.01 or more, and when a (−111) plane diffraction peak intensity of monoclinic ZrO 2 in XRD is denoted by A, a (011) plane diffraction peak intensity of Nd 2 O 3 is denoted by B, a (103) plane diffraction peak intensity of Mn 3 O 4 is denoted by C, and a (222) plane diffraction peak intensity of Mn 2 O 3 or a (211) plane diffraction peak intensity of NdMnO 3 is denoted by D, (B+C+D)/A is 0.9 or less.
  11. 11 . The organic matter decomposition catalyst according to claim 1 , wherein the ternary composite oxide is a first oxide, and the organic matter decomposition catalyst further comprises a second oxide.
  12. 12 . The organic matter decomposition catalyst according to claim 11 , wherein the second oxide is a single-component oxide or a binary composite oxide.
  13. 13 . The organic matter decomposition catalyst according to claim 11 , wherein an amount of the second oxide in the organic matter decomposition catalyst is 40 parts by mass or less per 100 parts by mass of the first oxide.
  14. 14 . A honeycomb structure coated with the organic matter decomposition catalyst according to claim 1 .
  15. 15 . A method for decomposing organic matter, the method comprising: oxidatively decomposing organic matter by heating the organic matter using the organic matter decomposition catalyst according to claim 1 .
  16. 16 . The method for decomposing organic matter according to claim 15 , further comprising: recovering a catalytic activity by heating the organic matter decomposition catalyst to a temperature higher than or equal to a heating temperature during the oxidative decomposition.
  17. 17 . The method for decomposing organic matter according to claim 16 , wherein the heating temperature is 300° C. to 900° C.
  18. 18 . An organic matter decomposition device comprising: a pipe through which organic matter flows; a heater that heats the organic matter that flows through the pipe; and the organic matter decomposition catalyst according to claim 1 within the pipe and that is heated by the heater.

Description

CROSS REFERENCE TO RELATED APPLICATIONS The present application is a continuation of International application No. PCT/JP2024/026744, filed Jul. 26, 2024, which claims priority to Japanese Patent Application No. 2023-127136, filed Aug. 3, 2023, the entire contents of each of which are incorporated herein by reference. TECHNICAL FIELD The present disclosure relates to an organic matter decomposition catalyst and also relates to an organic matter decomposition structure, a method for decomposing organic matter, and an organic matter decomposition device. BACKGROUND ART Purification of exhaust gas composed of hydrocarbon organic compounds commonly involves mixing the exhaust gas with an oxygen-containing gas, such as air, and heating the resulting mixture so that the hydrocarbon organic compounds are decomposed into water and carbon dioxide through an oxidation combustion reaction. Using a catalyst material enables exhaust gas purification at lower temperatures and higher rates, and therefore, the use of a catalytic exhaust gas purification device can reduce the energy and costs associated with exhaust gas treatment. Common catalysts include active components, such as platinum, palladium, manganese, and cobalt, supported on ceramics, such as alumina. Noble metals, such as platinum and palladium, enable exhaust gas treatment at lower temperatures than manganese- or cobalt-based catalysts, but noble metals are expensive. Patent Document 1 proposes a BaZr(Mn)O3 catalyst (BZM-type catalyst) for the purpose of improving the heat resistance of perovskite-type composite oxide catalysts. Non Patent Document 1 and Non Patent Document 2 propose Zr—Mn-based catalysts for the purpose of suppressing degradation during the decomposition of Cl-containing hydrocarbon gases. Patent Document 2 proposes that the characteristics of Zr—Mn-based catalysts are improved by performing hydrothermal treatment and high-temperature steam treatment during the process for producing Zr—Mn-based catalysts. Patent Document 1: Japanese Unexamined Patent Application Publication No. 2015-229137Patent Document 2: Chinese Patent No. 111790374 Non Patent Documents Non Patent Document 1: Jose I. Gutierrez-Ortiz et al., “Structure of Mn—Zr mixed oxides catalysts and their catalytic performance in the gas-phase oxidation of chlorocarbons,” Chemosphere, 2007, Vol. 68, pp. 1004-1012Non Patent Document 2: D. Doebber et al., “MnOx/ZrO2 catalysts for the total oxidation of methane and chloromethane,” Applied Catalysis B: Environmental, 2004, Vol. 52, pp. 135-143 SUMMARY OF THE DISCLOSURE Common exhaust gas decomposition catalysts include platinum group metals, such as platinum, rhodium, and palladium, supported on heat-resistant materials, such as alumina. In many catalysts in which an active component is supported on a carrier, such as alumina, fine particles of the active component are supported on the carrier to achieve high catalytic activity. As a result, the activity of the catalyst tends to easily degrade due to a reduction in material surface area. In many cases, catalysts used for exhaust gas decomposition treatment are exposed to high-temperature environments resulting from high-temperature exhaust gas and heat generation associated with the decomposition reaction. In addition, platinum, rhodium, and palladium are rare resources and expensive, and cost constraints may make it difficult to introduce a large amount of such metals into a large-scale catalytic exhaust gas treatment device. If a catalyst has insufficient heat resistance or poisoning resistance, its catalytic performance deteriorates in a short period, and it is thus difficult to use catalytic exhaust gas treatment, which tends to increase the energy costs for exhaust-gas treatment. Therefore, there is a need for catalysts that can be used stably at higher temperatures and catalyst materials resistant to degradation by catalyst poisoning components, such as sulfur(S), chlorine (Cl), and phosphorus (P). The BZM catalyst disclosed in Patent Document 1 has improved heat resistance; however, when exposed to exhaust gas containing a high concentration of S or Cl, the BZM catalyst may exhibit degradation in catalytic characteristics as a result of reactions between these elements and the catalyst components. The Zr—Mn-based catalysts disclosed in Non Patent Document 1, Non Patent Document 2, and Patent Document 2 exhibit resistance to chlorinated hydrocarbons, but have insufficient heat resistance at higher temperatures. When the exhaust-gas treatment temperature reaches a high temperature, the catalyst particles may aggregate, reducing the contact area between the catalyst and the gas and thereby degrading the exhaust gas purification performance. Since aggregation of catalyst particles causes deformation of the catalyst itself, cracking of pellet catalysts or peeling in catalyst-coated honeycomb structures may occur, generating dust and raising concerns about adverse effects on exhaust-gas