Organic matter decomposition catalyst, honeycomb structure, decomposition method for organic matter, and organic matter decomposition device

Abstract

The present disclosure relates to an organic matter decomposition catalyst and also relates to an organic matter decomposition structure that is coated with the organic matter decomposition catalyst, a decomposition method for organic matter that uses the organic matter decomposition catalyst, and an organic matter decomposition device that comprises the organic matter decomposition catalyst. This organic matter decomposition catalyst is for oxidatively decomposing organic matter. The organic matter decomposition catalyst includes a ternary composite oxide of zirconium, manganese, and neodymium and oxidatively decomposes organic matter. The present disclosure provides: an organic matter decomposition catalyst that exhibits high initial catalytic activity, maintains high catalytic activity after poisoning, and can be regenerated by heating even after poisoning; a honeycomb structure, a decomposition method for organic matter, and an organic matter decomposition device that use the organic matter decomposition catalyst.

Description

Organic matter decomposition catalyst, honeycomb structure, organic matter decomposition method, and organic matter decomposition device

[0001] The present disclosure relates to an organic matter decomposition catalyst, and further to an organic matter decomposition structure, an organic matter decomposition method, and an organic matter decomposition device.

[0002] The purification of exhaust gases consisting of hydrocarbon-based organic substances is generally achieved by mixing the exhaust gas with an oxygen-containing gas such as air, heating it, and decomposing it into water and carbon dioxide through an oxidative combustion reaction. The use of catalytic materials enables exhaust gas purification at lower temperatures and faster, so catalytic exhaust gas purification equipment can save energy and costs associated with exhaust gas treatment. The most common catalyst materials are those in which active components such as platinum, palladium, manganese, or cobalt are supported on ceramics such as alumina. Precious metals such as platinum and palladium can treat exhaust gases at lower temperatures than manganese- or cobalt-based catalysts, but they are expensive.

[0003] In Patent Document 1, BaZr(Mn)O is used to improve the heat resistance of a perovskite-type composite oxide catalyst. ３ A catalyst (BZM-based catalyst) has been proposed. Non-Patent Documents 1 and 2 propose a Zr-Mn-based catalyst for the purpose of suppressing deterioration due to the decomposition of hydrocarbon gases containing Cl. Patent Document 2 also proposes improving the properties of the Zr-Mn-based catalyst by performing hydrothermal treatment and high-temperature steam treatment in the manufacturing process.

[0004] Japanese Patent Publication No. 2015-229137 Chinese Patent No. 111790374

[0005] Jose I. Gutierrez-Ortiz and four others, "Structure of Mn-Zr mixed oxide catalysts and their catalytic performance in the gas-phase oxidation of chlorocarbons," Chemosphere, 2007, Vol. 68, pp. 1004-1012. Doebber, 3 others, "MnOx / ZrO2 catalysts for the total oxidation of methane and chloromethane", Applied Catalysis B: Environmental, 2004, Volume 52, Pages 135-143

[0006] Exhaust gas decomposition catalysts typically use catalysts in which platinum group metals such as platinum, rhodium, and palladium are supported on a heat-resistant material such as alumina. In catalysts in which an active component is supported on a support such as alumina, the active component is often supported on the support in the form of fine particles to achieve high catalytic activity. As a result, the catalyst's activity tends to deteriorate due to a decrease in the material's surface area. Furthermore, catalysts used to decompose exhaust gases are often exposed to high-temperature environments due to the high-temperature exhaust gases and heat generated by the decomposition reaction. Furthermore, platinum, rhodium, palladium, and other metals are rare resources and therefore expensive, and it may be difficult to introduce large amounts of them into large-scale catalytic exhaust gas treatment equipment due to cost constraints.

[0007] Furthermore, if the heat resistance or poisoning resistance of the catalyst is insufficient, the catalytic performance deteriorates in a short time, making it difficult to use catalytic exhaust gas treatment, and the energy cost for exhaust gas treatment tends to increase. Therefore, there is a demand for catalysts that can be used stably even at higher temperatures, and catalyst materials that are resistant to deterioration by catalyst poisoning components such as sulfur (S), chlorine (Cl), and phosphorus (P).

[0008] Although the BZM catalyst disclosed in Patent Document 1 has improved heat resistance, when exposed to exhaust gases containing high concentrations of S and Cl, the catalytic properties may deteriorate due to reactions with the catalyst components.

[0009] Although the Zr-Mn catalysts disclosed in Non-Patent Document 1, Non-Patent Document 2, and Patent Document 2 are durable against chlorinated hydrocarbons, their heat resistance at higher temperatures is still insufficient, and therefore, when the exhaust gas treatment temperature reaches a high temperature, the catalyst particles aggregate, reducing the contact area with the gas and possibly reducing the exhaust gas purification performance. Furthermore, the catalyst itself deforms as the catalyst particles aggregate, causing cracks in the case of pellet-type catalysts, and peeling in the case of catalyst-coated honeycomb structures, which may generate dust and adversely affect the exhaust gas treatment equipment and downstream processes.

[0010] Thus, the thermal durability of catalysts must have sufficient performance margin, taking into account not only the operating temperature of the exhaust gas treatment equipment, but also the temperature rise associated with the combustion of organic matter and the possibility of increasing the operating temperature to compensate for insufficient treatment capacity.

[0011] The object of the present disclosure is to provide an organic matter decomposition catalyst that exhibits high catalytic activity in the initial stage, maintains high catalytic activity even after poisoning, and can be regenerated by heating even if poisoned, as well as a honeycomb structure using the same, a method for decomposing organic matter, and an organic matter decomposition device.

[0012] The organic matter decomposition catalyst according to the present disclosure is an organic matter decomposition catalyst for oxidatively decomposing organic matter, and includes a ternary composite oxide containing zirconium, manganese, and neodymium.

[0013] According to the present disclosure, it is possible to provide an organic matter decomposition catalyst that exhibits high catalytic activity in the initial stage, maintains high catalytic activity even after poisoning, and can be regenerated by heating even if poisoned, as well as a honeycomb structure using the same, a method for decomposing organic matter, and an organic matter decomposition device.

[0014] Figure 1 is a schematic diagram for explaining the organic matter decomposition apparatus of the present disclosure. Figure 2 shows the XRD measurement results of the organic matter decomposition catalysts of Examples 6, 10, and 19. Figure 3 shows a TEM (transmission electron microscope) image and an EDX (energy dispersive X-ray spectroscopy) element mapping image of the organic matter decomposition catalyst of Example 10. Figure 4 is a schematic diagram for explaining the organic matter decomposition apparatus used in the examples.

[0015] Hereinafter, organic matter decomposition catalysts according to embodiments of the present disclosure will be described with reference to the drawings. In the following description of each embodiment, the same or corresponding parts in the drawings will be denoted by the same reference numerals, and description thereof will not be repeated.

[0016] <Organic Matter Decomposition Catalyst> The organic matter decomposition catalyst of the present disclosure is an organic matter decomposition catalyst for oxidatively decomposing organic matter, and includes a ternary composite oxide (hereinafter also referred to as a first oxide) containing zirconium (Zr), manganese (Mn), and neodymium (Nd). In this specification, the ternary composite oxide refers to an oxide that contains three elements other than oxygen and has a stable crystal structure.

[0017] The first oxide may be an oxide containing Zr, Mn, and Nd. The presence of the first oxide in the organic matter decomposition catalyst can be confirmed by elemental mapping using X-ray diffraction (XRD) analysis or EDX (energy dispersive X-ray spectroscopy) of a TEM (transmission electron microscope). The XRD analysis or TEM-EDX analysis shows that the crystalline structure of the first oxide is zirconium oxide (ZrO ２ It is confirmed that the crystal structure is a solid solution in which Mn and Nd are dispersed and inserted into the crystal lattice of Mn.

[0018] Examples of organic matter that can be oxidatively decomposed by the organic matter decomposition catalyst include hydrocarbon gases, sulfur compounds, and nitrogen compounds. The organic matter may be, for example, volatile organic compounds (VOCs). The organic matter decomposition catalyst of the present disclosure is suitable for the oxidative decomposition of hydrocarbon gases (e.g., aromatic hydrocarbons, alcohols, ketones, aldehydes, and carboxylic acids). The organic matter decomposition catalyst is used, for example, to purify harmful gases such as exhaust gases.

[0019] Regarding oxidative decomposition, the following formula (1): C７ H ８ +90 ２　 → 4H ２ O + 7CO ２ Taking the toluene combustion reaction shown in (1) as an example, toluene, which is subject to emission restrictions in the atmosphere, reacts with air (oxygen) to convert it into harmless water vapor and carbon dioxide. Because this reaction is exothermic, the reaction site is heated to high temperatures, especially when treating high-concentration gases or large quantities of gas. Furthermore, when sulfur or chlorine elements are contained in the organic structure of the hydrocarbons that make up the hydrocarbon gas, the sulfur or chlorine reacts with the catalyst components or strongly binds to the adsorption points on the catalyst surface, poisoning the catalyst and reducing its performance.

[0020] The organic matter decomposition catalyst tends to have improved heat resistance by containing the first oxide. ２ By adding both Mn and Nd to ZrO, the active sites are increased, improving the decomposition performance of organic matter. ２ This is thought to be because the surface energy of the catalyst changes, inhibiting the growth of crystal grains and improving heat resistance. As a result, the organic matter decomposition catalyst of the present disclosure tends to exhibit high catalytic activity in the initial activity even when calcined at a high temperature (e.g., 900°C) during its production process or when the catalyst is used at a high temperature, and tends to maintain high catalytic activity even after poisoning, and tends to be easily regenerated by heating even when poisoned. The initial activity, catalytic activity after poisoning, and catalytic activity after regeneration are evaluated according to the methods described in the Examples section below.

[0021] The organic matter decomposition catalyst containing the first oxide can exhibit higher catalytic activity in the initial stage than an organic matter decomposition catalyst containing a binary composite oxide without the first oxide, and can maintain high catalytic activity even after poisoning. The organic matter decomposition catalyst containing the first oxide can exhibit higher catalytic activity in the initial stage than, for example, an organic matter decomposition catalyst containing a binary composite oxide containing Zr and Mn without the first oxide, and an organic matter decomposition catalyst containing a binary composite oxide containing Nd and Zr without the first oxide, and can maintain high catalytic activity even after poisoning. This is because ZrO ２ By adding both Mn and Nd to ZrO, Mn and Nd are more effectively added than in a binary composite oxide to which only one of Mn and Nd is added. ２ As a result, the active sites increase and the decomposition performance of organic matter improves. ２ This is thought to be because the surface energy of the film is reduced, inhibiting the growth of crystal grains and improving heat resistance.

[0022] The organic decomposition catalyst of the present disclosure can exhibit high initial catalytic activity and can maintain high catalytic activity even after poisoning, even when compared with an organic decomposition catalyst that does not contain a first oxide and contains a mixture of a binary composite oxide containing Zr and Mn and a binary composite oxide containing Nd and Zr.

[0023] The organic matter decomposition catalyst may further contain an oxide (hereinafter also referred to as a second oxide) that exhibits catalytic activity in addition to the first oxide. The second oxide may contain, for example, one or more oxides containing manganese or neodymium. The second oxide may be, for example, a single-component oxide or a binary-composite oxide, and specific examples thereof include Mn ３ O ４ , Mn ２ O ３ and Nd ２ O ３ The organic matter decomposition catalyst may contain only the first oxide, or may contain only the first oxide and the second oxide, as oxides that exhibit catalytic activity.

[0024] The organic matter decomposition catalyst may be composed only of the first oxide, or may be composed only of the first oxide and the second oxide. Furthermore, the organic matter decomposition catalyst may contain a binder or an organic solvent to facilitate shaping into particles or a honeycomb shape, as described below, or to facilitate coating onto a structure. The content of the first oxide in the organic matter decomposition catalyst may be, for example, 100 mass% or less, 95 mass% or less, or 90 mass% or less, based on the mass of the organic matter decomposition catalyst. In a structure coated with an organic matter decomposition catalyst, such as the honeycomb-shaped structure coated with the organic matter decomposition catalyst described below, the mass of the organic matter decomposition catalyst refers to the mass of the organic matter decomposition catalyst coated on the structure, and does not include the mass of the structure (e.g., honeycomb-shaped ceramics, etc.).

[0025] When the organic matter decomposition catalyst contains a second oxide, the content of the second oxide may be, for example, 40 parts by mass or less, preferably 30 parts by mass or less, and may be, for example, more than 0 parts by mass, per 100 parts by mass of the first oxide.

[0026] The molar ratio of Mn to Zr in the organic matter decomposition catalyst may be, for example, in the range of 0.02 to 1.00, and preferably in the range of 0.05 to 0.70. When the molar ratio of Mn to Zr in the organic matter decomposition catalyst is in the above range, the heat resistance of the organic matter decomposition catalyst is improved, and as a result, the catalyst tends to exhibit high initial catalytic activity, to maintain high catalytic activity even after poisoning, and to be easily regenerated by heating even if poisoned.

[0027] The molar ratio of Nd to Zr in the organic matter decomposition catalyst may be, for example, in the range of 0.002 to 0.200, and preferably in the range of 0.010 to 0.150. When the molar ratio of Nd to Zr in the organic matter decomposition catalyst is in the above range, heat resistance is improved, and as a result, high catalytic activity is easily exhibited in the initial activity, high catalytic activity is easily maintained even after poisoning, and even if poisoned, regeneration by heating tends to be easier.

[0028] The organic matter decomposition catalyst is monoclinic ZrO ２The organic matter decomposition catalyst may contain one or more crystalline phases (second crystalline phases) other than the first crystalline phase. The second crystalline phase may be, for example, Mn. ３ O ４ Crystal phase, Mn ２ O ３ Crystal phase, Nd ２ O ３ Crystalline phase, cubic ZrO ２ Crystalline and tetragonal ZrO ２ The organic matter decomposition catalyst may contain a crystalline phase, etc. The organic matter decomposition catalyst may be confirmed by XRD analysis.

[0029] The organic matter decomposition catalyst has a molar ratio of manganese to zirconium of 0.05 or more, a molar ratio of neodymium to zirconium of 0.01 or more, and is monoclinic ZrO ２ The (-111) plane diffraction peak intensity of A, Nd ２ O ３ The (011) plane diffraction peak intensity of B, Mn ３ O ４ The (103) diffraction peak intensity of C and Mn ２ O ３ (222) or NdMnO ３ When the (211) plane diffraction peak intensity is D, (B+C+D) / A can be 0.9 or less. This allows high activity (toluene 90% decomposition temperature≦350°C) to be maintained even after calcination at 900°C. In addition, the heat resistance makes it possible to regenerate a catalyst whose performance has deteriorated due to poisoning by heating. The monoclinic phase ZrO, which is the main phase, ２ In contrast, catalysts containing a certain amount or more of Mn or Nd improve catalytic activity, but when excessive Mn or Nd is contained, as can be seen from the XRD measurement results, Mn ３ O ４ , Mn ２ O ３ , NdMnO ３ , Nd ２ O ３ The Mn and Nd that compose these heterogeneous phases are ２It is believed that the heterogeneous phase (Mn) confirmed by XRD measurement grows into particles at high temperatures without dispersing on the surface, which reduces the catalytic activity. ３ O ４ , Mn ２ O ３ , NdMnO ３ , Nd ２ O ３ ) relative to the sum of the XRD peak intensities of the main phase (monoclinic phase ZrO ２ The activity decrease can be easily suppressed by setting the ratio of the XRD peak intensities of the heterophase and the main phase (hereinafter also referred to as the heterophase / main phase peak ratio) to 0.9 or less. The above A, B, C, and D can be determined according to the method described in the Examples section below.

[0030] The organic matter decomposition catalyst can be prepared, for example, as follows. ２ , Mn ３ O ４ and Nd ２ O ３ To the mixture, pebbles, water, and an organic binder are added and mixed to obtain a mixture. A ball mill or the like can be used for mixing. Next, the mixture is dried in an oven at 120°C, crushed, and classified to obtain particles with particle sizes ranging from several hundred microns to several millimeters. The resulting particulate sample is then calcined in air at 900°C for two hours. In this way, an organic matter decomposition catalyst can be obtained.

[0031] The temperature at which the organic matter decomposition catalyst can exhibit catalytic activity in the initial stage may be, for example, 300°C or higher and 510°C or lower, and preferably 310°C or higher and 460°C or lower.

[0032] The temperature at which the organic matter decomposition catalyst can exhibit catalytic activity after poisoning may be, for example, 400°C or higher and 700°C or lower, preferably 420°C or higher and 620°C or lower, and more preferably 420°C or higher and 540°C or lower.

[0033] The temperature at which the organic matter decomposition catalyst can exhibit catalytic activity after regeneration by heating may be, for example, 300°C or higher and 700°C or lower, preferably 340°C or higher and 540°C or lower, and more preferably 340°C or higher and 470°C or lower.

[0034] The organic matter decomposition catalyst has improved heat resistance, exhibits high catalytic activity in the initial stage, maintains high catalytic activity even after poisoning, and can be regenerated by heating even if poisoned, making it suitable for decomposing volatile organic substances (VOCs) that are generated in processes such as painting, molding, combustion, and waste treatment in the living environment and industrial fields and cause environmental pollution. The organic matter decomposition catalyst can also be used for purifying automobile exhaust gases, etc.

[0035] <Form of organic decomposition catalyst> The organic decomposition catalyst can be used in the form of a pellet catalyst processed into granules of a few millimeters to a few centimeters in size, or a honeycomb catalyst processed into a honeycomb shape. Alternatively, the organic decomposition catalyst can be coated on the surface of a honeycomb-shaped ceramic to create a honeycomb structure coated with the organic decomposition catalyst. The honeycomb shape can reduce pressure loss when gas flows through it. Furthermore, increasing the honeycomb cell density increases the effective surface area, making it easier to increase the decomposition rate of organic matter.

[0036] <Method for Decomposing Organic Matter> A method for decomposing organic matter according to another embodiment of the present disclosure is a method for decomposing organic matter, and includes a decomposition step of oxidatively decomposing the organic matter by heating using the organic matter decomposition catalyst described above. In the decomposition step, the organic matter can be decomposed by heating the organic matter while contacting it with the organic matter decomposition catalyst. The above description of the organic matter applies to the organic matter. The method for decomposing organic matter can be carried out using an organic matter decomposition device described below.

[0037] The heating temperature in the decomposition step may be, for example, 300°C or higher and 900°C or lower. If the heating temperature in the decomposition step is within the above range, the catalytic activity of the organic matter decomposition catalyst can be exerted, and the catalytic activity can be exerted even after poisoning. From the viewpoints of suppressing deterioration in catalyst performance and energy costs, the heating temperature in the decomposition step is preferably 300°C or higher and 700°C or lower, more preferably 300°C or higher and 600°C or lower, and even more preferably 300°C or higher and 540°C or lower.

[0038] One method of heating organic matter while bringing it into contact with an organic matter decomposition catalyst is to fill a tube with the organic matter decomposition catalyst, introduce the organic matter into the tube, and heat the area inside the tube where the organic matter is in contact with the organic matter decomposition catalyst from the outside. The organic matter decomposition catalyst filled in the tube can be the above-mentioned pellet-shaped catalyst, honeycomb catalyst, or honeycomb structure coated with the organic matter decomposition catalyst. It can also be an aggregate of the organic matter decomposition catalyst.

[0039] The organic matter decomposition method may further include a regeneration step of restoring catalytic activity by heating the organic matter decomposition catalyst used in the decomposition step to a temperature equal to or higher than the heating temperature in the decomposition step. The regeneration step may be carried out by heating the organic matter decomposition catalyst used in the decomposition step to a temperature equal to or higher than the heating temperature in the decomposition step while contacting it with air. The organic matter decomposition catalyst used in the decomposition step may be poisoned by S, Cl, P, etc.

[0040] The temperature above the heating temperature in the decomposition step may be, for example, 300°C or higher and 900°C or lower, and from the viewpoint of the catalytic activity of the regenerated catalyst and energy costs, is preferably 400°C or higher and 800°C or lower, more preferably 600°C or higher and 800°C or lower.

[0041] The method of heating the organic matter decomposition catalyst used in the decomposition step while bringing it into contact with air can be carried out, for example, by introducing air into a tube filled with the organic matter decomposition catalyst used in the decomposition step and heating the tube from outside.

[0042] An organic matter decomposition device according to another embodiment of the present disclosure includes a pipe through which organic matter flows and a heating unit that heats the organic matter flowing through the pipe. The organic matter decomposition catalyst described above is disposed in a region inside the pipe that is heated by the heating unit.

[0043] The organic matter decomposition apparatus will be described with reference to Fig. 1. The organic matter decomposition apparatus 10 shown in Fig. 1 includes a pipe 1 through which organic matter flows, a heating unit 2 for heating the organic matter flowing through the pipe 1, and a control unit 3 for controlling the heating unit 2.

[0044] An organic matter decomposition catalyst 6 is disposed in the region inside the tube 1 that is heated by the heating unit 2. The organic matter decomposition catalyst 6 may be the organic matter decomposition catalyst described above, and may be in the form of an aggregate, the pellet-shaped catalyst described above, a honeycomb catalyst, or a honeycomb structure coated with the organic matter decomposition catalyst.

[0045] The pipe 1 has a gas inlet 4 on the upstream side. The gas inlet 4 is connected to a gas supply pipe 7. On the upstream side of the pipe 1, the gas supply pipe 7 has an organic substance supply line 41 for supplying an organic substance (e.g., toluene) and a nitrogen (N ２ a nitrogen supply line 42 for supplying oxygen (O ２ ) is connected to the pipe 1. That is, the gas to be treated containing organic matter, nitrogen, and oxygen is supplied to the pipe 1 via the gas supply pipe 7.

[0046] The pipe 1 has a reaction gas outlet 5 on the downstream side. A gas exhaust pipe 8 is connected to the reaction gas outlet 5 for discharging the treated gas from the system after the organic matter has been decomposed in the pipe 1. A sampling line 51 for sampling the treated gas is connected to the gas exhaust pipe 8, and is configured so that the concentration of organic matter in the treated gas can be analyzed by gas chromatography.

[0047] The control unit 3 is configured to be able to control the temperature of the region heated by the heating unit 2 to be, for example, 300°C or higher and 900°C or lower.

[0048] The control unit 3 is also configured to be able to control the heating unit 2 so that the temperature of the organic matter decomposition catalyst 6 is between 300° C. and 900° C. By controlling the temperature of the organic matter decomposition catalyst 6 to be between 300° C. and 900° C., the catalytic activity of the organic matter decomposition catalyst 6 can be further increased. Furthermore, by controlling the temperature of the organic matter decomposition catalyst 6 to be 900° C. or less, deterioration of the organic matter decomposition catalyst 6 can be suppressed.

[0049] Furthermore, after the decomposition of organic matter, the organic matter decomposition catalyst 6 can be regenerated without supplying organic matter, by supplying oxygen and nitrogen to the pipe 1 while controlling the temperature of the organic matter decomposition catalyst 6 with the heating unit 2 to a temperature equal to or higher than the heating temperature in the decomposition step using the control unit 3, thereby restoring the catalytic activity of the organic matter decomposition catalyst 6. The regeneration treatment is intended to release catalyst poison components by heating, so it is necessary to heat the catalyst to a temperature equal to or higher than the operating temperature, but it can also be performed while organic matter is being supplied.

[0050] The present disclosure will be described in more detail below with reference to examples. In the examples, "%" and "parts" refer to mass % and mass parts unless otherwise specified. The organic matter decomposition catalysts of the following examples and comparative examples were analyzed using an X-ray fluorescence analyzer to confirm that they had the compositions of the organic matter decomposition catalysts shown in Tables 1 and 2.

[0051] Example 1: ZrO as a raw material for an organic matter decomposition catalyst ２ and Mn ３ O ４ and Nd ２ O ３ The Zr:Mn:Nd molar ratio was weighed out to a value of 1.00:0.10:0.002, and then mixed with pebbles, water, and an organic binder. The resulting mixture was dried in an oven at 120°C, crushed, and classified to obtain granules of 0.5 to 0.7 mm. The resulting granular sample was calcined in air at 900°C for 2 hours to obtain the organic matter decomposition catalyst of Example 1.

[0052] Example 2: ZrO as a raw material for organic matter decomposition catalyst ２ and Mn ３ O ４ and Nd ２ O ３ An organic matter decomposition catalyst of Example 2 was obtained in the same manner as in Example 1, except that the above were used and weighed out so that the molar ratio of Zr:Mn:Nd was 1.00:0.10:0.005.

[0053] Example 3: ZrO as a raw material for an organic matter decomposition catalyst ２ and Mn ３ O ４ and Nd ２ O３ An organic matter decomposition catalyst of Example 3 was obtained in the same manner as in Example 1, except that the above were used and weighed out so that the molar ratio of Zr:Mn:Nd was 1.00:0.10:0.010.

[0054] Example 4: ZrO as a raw material for organic matter decomposition catalyst ２ and Mn ３ O ４ and Nd ２ O ３ An organic matter decomposition catalyst of Example 4 was obtained in the same manner as in Example 1, except that the above were used and weighed out so that the molar ratio of Zr:Mn:Nd was 1.00:0.10:0.020.

[0055] Example 5: ZrO as a raw material for organic matter decomposition catalyst ２ and Mn ３ O ４ and Nd ２ O ３ The organic matter decomposition catalyst of Example 5 was obtained in the same manner as in Example 1, except that the above were used and weighed out so that the molar ratio of Zr:Mn:Nd was 1.00:0.10:0.050.

[0056] Example 6: ZrO as a raw material for organic matter decomposition catalyst ２ and Mn ３ O ４ and Nd ２ O ３ The organic matter decomposition catalyst of Example 6 was obtained in the same manner as in Example 1, except that the above were used and weighed out so that the molar ratio of Zr:Mn:Nd was 1.00:0.10:0.100.

[0057] Example 7: ZrO as a raw material for organic matter decomposition catalyst ２ and Mn ３ O ４ and Nd ２ O ３ The organic matter decomposition catalyst of Example 7 was obtained in the same manner as in Example 1, except that the above were used and weighed out so that the molar ratio of Zr:Mn:Nd was 1.00:0.10:0.150.

[0058] Example 8: ZrO as a raw material for organic matter decomposition catalyst ２ and Mn ３ O ４ and Nd ２ O３ The organic matter decomposition catalyst of Example 8 was obtained in the same manner as in Example 1, except that the above were used and weighed out so that the molar ratio of Zr:Mn:Nd was 1.00:0.10:0.200.

[0059] Example 9: ZrO as a raw material for organic matter decomposition catalyst ２ and Mn ３ O ４ and Nd ２ O ３ The organic matter decomposition catalyst of Example 9 was obtained in the same manner as in Example 1, except that the above were used and weighed out so that the molar ratio of Zr:Mn:Nd was 1.00:0.01:0.100.

[0060] Example 10: ZrO as a raw material for organic matter decomposition catalyst ２ and Mn ３ O ４ and Nd ２ O ３ An organic matter decomposition catalyst of Example 10 was obtained in the same manner as in Example 1, except that the above were used and weighed out so that the molar ratio of Zr:Mn:Nd was 1.00:0.05:0.100.

[0061] Example 11: ZrO as a raw material for organic matter decomposition catalyst ２ and Mn ３ O ４ and Nd ２ O ３ An organic matter decomposition catalyst of Example 11 was obtained in the same manner as in Example 1, except that the above were used and weighed out so that the molar ratio of Zr:Mn:Nd was 1.00:0.15:0.100.

[0062] Example 12: ZrO as a raw material for organic matter decomposition catalyst ２ and Mn ３ O ４ and Nd ２ O ３ An organic matter decomposition catalyst of Example 12 was obtained in the same manner as in Example 1, except that the above were used and weighed out so that the molar ratio of Zr:Mn:Nd was 1.00:0.20:0.100.

[0063] Example 13: ZrO as a raw material for organic matter decomposition catalyst ２ and Mn ３ O ４ and Nd２ O ３ An organic matter decomposition catalyst of Example 13 was obtained in the same manner as in Example 1, except that the above were used and weighed out so that the molar ratio of Zr:Mn:Nd was 1.00:0.40:0.100.

[0064] Example 14: ZrO as a raw material for organic matter decomposition catalyst ２ and Mn ３ O ４ and Nd ２ O ３ The organic matter decomposition catalyst of Example 14 was obtained in the same manner as in Example 1, except that the above were used and weighed out so that the molar ratio of Zr:Mn:Nd was 1.00:0.70:0.100.

[0065] Example 15: ZrO as a raw material for organic matter decomposition catalyst ２ and Mn ３ O ４ and Nd ２ O ３ The organic matter decomposition catalyst of Example 15 was obtained in the same manner as in Example 1, except that the above were used and weighed out so that the molar ratio of Zr:Mn:Nd was 1.00:1.00:0.100.

[0066] Example 16: ZrO as a raw material for organic matter decomposition catalyst ２ and Mn ３ O ４ and Nd ２ O ３ The organic matter decomposition catalyst of Example 16 was obtained in the same manner as in Example 1, except that the above were used and weighed out so that the molar ratio of Zr:Mn:Nd was 1.00:0.02:0.002.

[0067] Example 17: ZrO as a raw material for organic matter decomposition catalyst ２ and Mn ３ O ４ and Nd ２ O ３ The organic matter decomposition catalyst of Example 17 was obtained in the same manner as in Example 1, except that the above were used and weighed out so that the molar ratio of Zr:Mn:Nd was 1.00:0.02:0.150.

[0068] Example 18: ZrO as a raw material for organic matter decomposition catalyst ２ and Mn ３ O４ and Nd ２ O ３ The organic matter decomposition catalyst of Example 18 was obtained in the same manner as in Example 1, except that the above were used and weighed out so that the molar ratio of Zr:Mn:Nd was 1.00:0.40:0.002.

[0069] Example 19: ZrO as a raw material for organic matter decomposition catalyst ２ and Mn ３ O ４ and Nd ２ O ３ The organic matter decomposition catalyst of Example 19 was obtained in the same manner as in Example 1, except that the above were used and weighed out so that the molar ratio of Zr:Mn:Nd was 1.00:0.40:0.150.

[0070] Example 20: ZrO as a raw material for organic matter decomposition catalyst ２ and Mn ３ O ４ and Nd ２ O ３ The organic matter decomposition catalyst of Example 20 was obtained by carrying out the steps from mixing to calcination in the same manner as in Example 1, except that the above were used and weighed out so that the molar ratio of Zr:Mn:Nd was 1.00:0.10:0.250.

[0071] <Comparative Example 1> BaCO as a raw material for organic matter decomposition catalyst ３ and ZrO ２ and Mn ３ O ４ The mixture was weighed out so that the molar ratio of Ba:Zr:Mn was 1.00:0.90:0.10, and then mixed with pebbles, water, and an organic binder. The resulting mixture was dried in an oven at 120°C, crushed, and classified to form granules of 0.5 to 0.7 mm. The resulting granular sample was calcined in air at 1000°C for 2 hours to obtain the organic matter decomposition catalyst of Comparative Example 1.

[0072] Comparative Example 2: ZrO was used as a raw material for the organic matter decomposition catalyst. ２ and Mn ３ O ４ The organic matter decomposition catalyst of Comparative Example 2 was obtained by carrying out the processes from mixing to calcination in the same manner as in Example 1, except that the above were used and weighed out so that the molar ratio of Zr:Mn was 1.00:0.02.

[0073] Comparative Example 3 An organic matter decomposition catalyst of Comparative Example 3 was obtained by carrying out the processes from mixing to calcination in the same manner as in Example 1, except that ZrO2 and Nd2O3 were used as raw materials for the organic matter decomposition catalyst and were weighed out so that the molar ratio of Zr:Nd was 1.00:0.10.

[0074] [Confirmation of Crystalline Phase] The organic matter decomposition catalysts of the Examples and Comparative Examples were pulverized in a mortar and mortar, and the crystalline phases were confirmed by powder XRD measurement (X-ray source: Cu-Kα1). The types of crystalline phases detected in the organic matter decomposition catalysts of the Examples and Comparative Examples are shown in Table 1.

[0075] [Measurement of the peak ratio of the heterogeneous phase to the main phase] The monoclinic ZrO phase, which is the main phase of the present catalyst, ２ Heterogeneous phase components confirmed by powder XRD measurement: Mn ３ O ４ , Mn ２ O ３ , NdMnO ３ , Nd ２ O ３ In order to quantify the content of ZrO, the heterophase / main phase peak ratio, which is the ratio of the "sum of diffraction peak intensities of heterophase components" to the "diffraction peak intensity of the main phase component" confirmed from the powder XRD measurement results, was calculated and the results are shown in Table 1. Here, the maximum value of the diffraction peak intensity from the following crystal planes was used as the diffraction peak intensity of each crystal phase. A: Monoclinic phase ZrO existing at 2θ = 27.5 to 28.8 degrees ２ B: Diffraction peak intensity of the (-111) plane of Nd present at 2θ = 30.6 to 31.0 degrees ２ O ３ C: Diffraction peak intensity of the (103) plane of Mn present at 2θ = 32.1 to 32.5 degrees ３ O ４ Diffraction peak intensity of the (103) plane D: Mn present at 2θ = 32.6 to 33.2 degrees ２ O ３ Diffraction peak intensity of the (222) plane of NdMnO ３ Diffraction peak intensity of the (211) plane of Mn ２ O ３ and NdMnO ３ Since the strongest lines of Mn appear in the same accuracy region, the maximum intensity of the diffraction peaks present at 2θ = 32.6 to 33.2 degrees is ２O ３ and NdMnO ３ The peak intensity was

[0076]

[0077] As shown in Table 1, the catalysts of Examples 1 to 20 contained monoclinic ZrO ２ Crystal phase (in Table 1, m-ZrO ２ The Mn ３ O ４ , Mn ２ O ３ , Nd ２ O ３ , cubic or tetragonal ZrO ２ Crystal phase (in Table 1, c-ZrO ２ Also, a crystalline phase of a perovskite structure was confirmed in the catalyst of Comparative Example 1.

[0078] The XRD measurement results of Examples 6, 10, and 19 are shown in Figure 2. The catalyst of Example 6, which is composed of Zr-Mn-Nd, is m-ZrO ２ , Mn ２ O ３ and NdMnO ３ was detected, but Nd ２ O ３ and Mn ３ O ４ was not detected, so ZrO ２ By adding Mn and Nd simultaneously to monoclinic ZrO ２ It is believed that the Nd ２ O ３ and Mn ３ O ４ Not only Mn ２ O ３ and NdMnO ３ Since neither Nd nor Mn was detected, it is considered that Nd and Mn are present in the monoclinic ZrO ２ It is considered that the Mn and Nd particles penetrate into the crystalline phase and are highly dispersed. ２ and Mn ３ O ４The addition of excessive Mn or Nd results in the formation of ZrO other than the monoclinic phase. ２ It is believed that unstructured and undispersed Mn and Nd are produced.

[0079] 3 shows a TEM (transmission electron microscope) image of Example 10 and an elemental mapping image of Zr, Mn, and Nd by EDX (energy dispersive X-ray spectroscopy) in the same field of view. The distributions of Zr, Mn, and Nd present in the catalyst particles of Example 10 are consistent, and it is clear that the distributions of Zr, Mn, and Nd present in the catalyst particles of Example 10 are consistent with those of zirconium oxide (ZrO ２ It is considered that the crystal structure is a solid solution in which Mn and Nd are dispersed and inserted into the crystal lattice of Mn.

[0080] [Evaluation of Initial Catalyst Activity] A toluene combustion reaction was carried out using the catalysts of the examples and comparative examples. 0.1 cc of organic matter decomposition catalyst 103 was packed into the reaction tube 101 of the organic matter decomposition device 100 shown in FIG. 4 and heated to a predetermined temperature by the heater 102. Air containing 1000 ppm of toluene was introduced through the gas inlet 104 at a flow rate of 580 cc / min. During the test, post-reaction gas was sampled from the reaction gas outlet 105, and the outlet toluene concentration [ppm] was measured using a gas chromatograph. The toluene decomposition rate was confirmed according to the following formula: Toluene decomposition rate [%] = (1000 - outlet toluene concentration) / 1000. The test temperature was increased from 200°C in 10°C increments, and the temperature at which the toluene decomposition rate reached 90% was designated the "toluene 90% decomposition temperature." The results are shown in Table 2.

[0081] [SO ２ Evaluation of catalytic activity after poisoning] For each of the catalysts of the examples and comparative examples, ２ 4, 0.1 cc of organic matter decomposition catalyst 103 was filled in reaction tube 101 of organic matter decomposition apparatus 100 shown in FIG. 4, and heated to a temperature of 600° C. by heater 102. 50 ppm of SO was introduced from gas inlet 104. ２ Air containing SO was introduced at a flow rate of 580 cc / min and maintained for 2 hours, after which the temperature was lowered. ２ The "toluene 90% decomposition temperature" of the poisoned catalyst was measured. The results are shown in Table 2.

[0082] [Evaluation of catalytic activity after thermal regeneration] For each of the catalysts of the examples and comparative examples, ２ After carrying out poisoning treatment using the same method as in "Evaluation of catalytic activity after poisoning," 0.1 cc of organic matter decomposition catalyst 103 was filled into tube 1 of organic matter decomposition apparatus 100 shown in Figure 4, heated to a temperature of 800°C using heater 102, and air was introduced from gas inlet 104 at a flow rate of 580 cc / min. This was maintained for 0.5 hours, and then the temperature was lowered. Thereafter, the "toluene 90% decomposition temperature" of the catalyst after thermal regeneration was measured using the same method as in "Evaluation of initial catalyst activity." The results are shown in Table 2.

[0083] Example 21: The catalyst of Example 5 was mixed with pebbles, water, and an organic binder, and then crushed and mixed to form a catalyst slurry. A cordierite honeycomb (200 cpsi) was immersed in the resulting catalyst slurry for one minute, and then blown with air to coat it with the catalyst. The honeycomb-coated catalyst of Example 21 was then obtained by drying in an oven at 120°C and firing at 800°C for 2 hours. The catalyst coating weight per honeycomb volume was 100 g / L.

[0084] [Evaluation of honeycomb-coated catalyst properties] A honeycomb catalyst for activity evaluation, measuring 14 cells and 50 mm in length, was cut out from the honeycomb-coated catalyst of Example 21. The same conditions as in Example 5 were used except that the honeycomb-coated catalyst of Example 21 was used as the organic matter decomposition catalyst 103. [Evaluation of initial catalyst activity], [SO ２ The catalytic activity evaluation after poisoning and the catalytic activity evaluation after thermal regeneration were carried out. The results are shown in Table 2.

[0085]

[0086] The organic matter decomposition catalysts of Examples 1 to 20 exhibited high catalytic activity in the initial stage, maintained high catalytic activity even after poisoning, and were able to be regenerated by heating even after poisoning. On the other hand, the organic matter decomposition catalyst of Comparative Example 1 exhibited high catalytic activity in the initial stage, maintained high catalytic activity even after poisoning, and was able to be regenerated by heating even after poisoning. ２Poisoning significantly reduced the decomposition performance, and the toluene decomposition rate did not reach 90% even at a temperature of 700° C. Furthermore, the organic matter decomposition catalyst of Comparative Example 1 did not recover its catalytic activity even after thermal regeneration treatment at a temperature of 800° C. Furthermore, in Comparative Examples 2 and 3, high catalytic activity was not obtained in any of the initial activity, catalytic activity after poisoning, and activity after thermal regeneration.

[0087] In the honeycomb-coated catalyst of Example 21, poisoning progresses from the surface of the coating layer that comes into direct contact with the flowing gas, so the activity after poisoning tends to decrease compared to the granular catalyst (Example 5), but the initial activity and recovery by regeneration treatment show similar characteristics. Furthermore, the honeycomb catalyst can reduce the pressure loss during the gas flow reaction; while the pressure loss during catalytic activity evaluation for the granular catalyst (Example 5) rose to 6 kPa, the honeycomb-coated catalyst (Example 21) was able to maintain a pressure loss of 1 kPa or less.

[0088] In the above-described embodiments, configurations that can be combined may be combined with each other.

[0089] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0090] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0091] (Item 1) An organic matter decomposition catalyst according to one embodiment is an organic matter decomposition catalyst for oxidatively decomposing organic matter. The organic matter decomposition catalyst includes a ternary composite oxide containing zirconium, manganese, and neodymium.

[0092] (Item 2) In the organic matter decomposition catalyst according to item 1, the molar ratio of manganese to zirconium in the organic matter decomposition catalyst is in the range of 0.02 to 1.00.

[0093] (Item 3) In the organic matter decomposition catalyst according to item 1, the molar ratio of manganese to zirconium in the organic matter decomposition catalyst is in the range of 0.05 to 0.70.

[0094] (Item 4) In the organic matter decomposition catalyst according to any one of Items 1 to 3, the molar ratio of neodymium to zirconium in the organic matter decomposition catalyst is in the range of 0.002 to 0.200.

[0095] (Item 5) In the organic matter decomposition catalyst according to any one of Items 1 to 3, the molar ratio of neodymium to zirconium in the organic matter decomposition catalyst is in the range of 0.010 to 0.150.

[0096] (Item 6) The organic matter decomposition catalyst according to any one of Items 1 to 5 contains a monoclinic zirconium oxide crystal phase.

[0097] (Item 7) The organic matter decomposition catalyst according to any one of Items 1 to 6 is an organic matter decomposition catalyst in which the molar ratio of manganese to zirconium is 0.05 or more, the molar ratio of neodymium to zirconium is 0.01 or more, and the organic matter decomposition catalyst is characterized by monoclinic ZrO ２ The (-111) plane diffraction peak intensity of A, Nd ２ O ３ The (011) plane diffraction peak intensity of B, Mn ３ O ４ The (103) diffraction peak intensity of C and Mn ２ O ３ (222) or NdMnO ３ When the (211) plane diffraction peak intensity is D, (B+C+D) / A is 0.9 or less.

[0098] (Item 8) A honeycomb structure coated with the organic matter decomposition catalyst according to any one of Items 1 to 7.

[0099] (Item 9) A method for decomposing organic matter, comprising a decomposition step of oxidatively decomposing organic matter by heating using the organic matter decomposition catalyst according to any one of Items 1 to 7.

[0100] (Item 10) The method for decomposing organic matter according to item 9, further comprising a regeneration step of heating the organic matter decomposition catalyst used in the decomposition step to a temperature equal to or higher than the heating temperature in the decomposition step to restore catalytic activity.

[0101] (Item 11) An organic matter decomposition device comprising a pipe through which organic matter flows and a heating unit that heats the organic matter flowing through the pipe, wherein the organic matter decomposition catalyst according to any one of Items 1 to 7 is disposed in an area inside the pipe that is heated by the heating unit.

[0102] REFERENCE SIGNS LIST 1 Tube, 2 Heating section, 3 Control section, 4, 104 Gas inlet, 5, 105 Reaction gas outlet, 6, 103 Organic matter decomposition catalyst, 7 Gas supply pipe, 8 Gas exhaust pipe, 10, 100 Organic matter decomposition device, 41 Organic matter supply line, 42 Nitrogen supply line, 43 Oxygen supply line, 51 Sampling line, 101 Reaction tube, 102 Heater.

Claims

1. An organic matter decomposition catalyst for oxidatively decomposing organic matter, comprising a ternary composite oxide containing zirconium, manganese, and neodymium.

2. The organic matter decomposition catalyst according to claim 1, wherein the molar ratio of manganese to zirconium in the organic matter decomposition catalyst is in the range of 0.02 to 1.

00.

3. The organic matter decomposition catalyst according to claim 1, wherein the molar ratio of manganese to zirconium in the organic matter decomposition catalyst is in the range of 0.05 to 0.

70.

4. The organic matter decomposition catalyst according to any one of claims 1 to 3, wherein the molar ratio of neodymium to zirconium in the organic matter decomposition catalyst is in the range of 0.002 to 0.

200.

5. The organic matter decomposition catalyst according to any one of claims 1 to 3, wherein the molar ratio of neodymium to zirconium in the organic matter decomposition catalyst is in the range of 0.010 to 0.

150.

6. The organic matter decomposition catalyst according to any one of claims 1 to 5, which contains a monoclinic zirconium oxide crystal phase.

7. The molar ratio of manganese to zirconium in the organic matter decomposition catalyst is 0.05 or more, and the molar ratio of neodymium to zirconium is 0.01 or more, and the monoclinic ZrO ２ The (-111) plane diffraction peak intensity of Nd ２ O ３ The (011) diffraction peak intensity of B is ３ O ４ The (103) diffraction peak intensity of C and Mn ２ O ３ (222) or NdMnO ３ 7. The organic matter decomposition catalyst according to claim 1, wherein (B+C+D) / A is 0.9 or less, where D is the (211) plane diffraction peak intensity.

8. A honeycomb structure coated with the organic matter decomposition catalyst according to any one of claims 1 to 7.

9. A method for decomposing organic matter, comprising a decomposition step of oxidatively decomposing organic matter by heating using the organic matter decomposition catalyst according to any one of claims 1 to 7.

10. The method for decomposing organic matter according to claim 9, further comprising a regeneration step of recovering catalytic activity of the organic matter decomposition catalyst used in the decomposition step by heating the catalyst to a temperature equal to or higher than the heating temperature in the decomposition step.

11. An organic matter decomposition device comprising: a pipe through which organic matter flows; and a heating unit that heats the organic matter flowing through said pipe, wherein an organic matter decomposition catalyst according to any one of claims 1 to 7 is disposed in an area inside said pipe that is heated by said heating unit.

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