VOC removal catalyst, its manufacturing method, and VOC removal method

Abstract

To provide a VOC removal catalyst that can be easily produced, has excellent VOC removal efficiency, and can efficiently remove VOCs even at low temperature, a production method thereof, and a VOC removal method.SOLUTION: A production method of a VOC removal catalyst includes a step 1 for mixing a raw material containing a metal element M and a gelatinizer to obtain a gelatinous precursor and a step 2 for burning a product material obtained by mixing the gelatinous precursor and an oxidizer containing Mn, to obtain a complex oxide containing Mn and the metal element M. The metal element M is at least one selected from the group consisting of transition metals, rare-earth elements, and noble metal elements.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a VOC removal catalyst, a method for producing the same, and a method for removing VOCs. Regarding. [Background technology]

[0002] VOC is an abbreviation for volatile organic compounds, and known examples include toluene, xylene, benzene, ethyl acetate, methanol, and dichloromethane. While such VOCs are widely used in solvents, adhesives, chemical raw materials, etc., they have been pointed out as a cause of photochemical oxidants or suspended particulate matter (SPM), and therefore their emissions are strictly regulated by the Air Pollution Control Act. For this reason, there is a need to establish technology to more efficiently remove VOCs in order to further reduce VOC emissions.

[0003] A catalytic oxidation method is known as a technique for removing VOCs. This method is considered the most promising because it removes VOCs at relatively low temperatures. Because catalytic oxidation methods mainly use transition metal oxides, they are more cost-effective than noble metal catalysts, and from this perspective, research into improving the catalytic performance of transition metal oxides has been widely conducted. For example, Patent Document 1 discloses a technique for efficiently removing VOCs using a material containing manganese (IV) oxide. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-147131 Summary of the Invention [Problem to be solved by the invention]

[0005] However, conventional VOC removal catalysts are still not sufficient in VOC removal performance in low-temperature environments, and their production also requires time, so overall, there are still challenges to overcome when considering practical application. From these perspectives, there is currently a need for the development of a catalyst that can be easily produced and can efficiently remove VOCs even at low temperatures.

[0006] The present invention has been made in view of the above, and aims to provide a VOC removal catalyst that is easy to produce, has excellent VOC removal efficiency, and can efficiently remove VOCs even at low temperatures, a method for producing the same, and a method for removing VOCs. [Means for solving the problem]

[0007] As a result of extensive research into achieving the above object, the present inventors have found that the above object can be achieved by using a specific Mn-based composite oxide as an essential component, or by using a Mn-based composite oxide produced through a specific process as an essential component, and have thus completed the present invention.

[0008] That is, the present invention includes, for example, the subject matter described in the following sections. Item 1 A method for producing a VOC removal catalyst, Step 1: Mixing a raw material containing a metal element M with a gelling agent to obtain a gel precursor; and step 2 of calcining a product obtained by mixing the gel precursor with an oxidizing agent containing Mn to obtain a composite oxide containing Mn and a metal element M, The manufacturing method, wherein the metal element M is at least one element selected from the group consisting of transition metals, rare earth elements, and noble metal elements. Section 2 Item 2. The method according to Item 1, wherein the metal element M is at least one selected from the group consisting of Co, Fe, Ni, Cu, Zn, Ti, V, Zr, Nb, Mo, Ir, Ru, and W. Section 3 Item 3. The method according to Item 1 or 2, wherein the gelling agent is starch. Section 4 4. The method according to any one of items 1 to 3, wherein the composite oxide contains 1 to 35 mol % of Mn element. Section 5 A VOC removal catalyst, A composite oxide containing Mn and a metal element M, wherein the metal element M is at least one element selected from the group consisting of transition metals, rare earth elements, and noble metal elements, The VOC removal catalyst, wherein the composite oxide has an amorphous main phase. Section 6 Item 6. The VOC removal catalyst according to Item 5, wherein the metal element M is at least one selected from the group consisting of Co, Fe, Ni, Cu, Zn, Ti, V, Zr, Nb, Mo, Ir, Ru, and W. Section 7 Item 7. The VOC removal catalyst according to Item 5 or 6, wherein the composite oxide contains 1 to 35 mol % of Mn element. Item 8 8. A method for removing VOCs, comprising a step of decomposing VOCs using a VOC removal catalyst obtained by the production method according to any one of items 1 to 4 or the VOC removal catalyst according to any one of items 5 to 7. [Effects of the Invention]

[0009] The VOC removal catalyst of the present invention is easy to produce, has excellent VOC removal efficiency, and can efficiently remove VOCs even at low temperatures. Furthermore, the method for producing the VOC removal catalyst of the present invention allows the above-mentioned VOC removal catalyst of the present invention to be produced in a simple manner. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram showing the flow of an evaluation test method for a VOC removal catalyst. [Figure 2] 1 shows SEM images of VOC removal catalysts obtained in Examples and Comparative Examples. [Figure 3] 1 shows XRD spectra of VOC removal catalysts obtained in Examples and Comparative Examples. [Figure 4] The results of VOC removal tests using the VOC removal catalysts obtained in the examples and comparative examples are shown below. DETAILED DESCRIPTION OF THE INVENTION

[0011]

[0023] In the present specification, the terms "contain" and "comprise" include the concepts of "contain," "comprise," "consist essentially of," and "consist only of."

[0012] 1. Manufacturing method of VOC removal catalyst The production method of the present invention includes the following steps 1 and 2. Step 1: A step of mixing a raw material containing a metal element M with a gelling agent to obtain a gel precursor. Step 2: A step of calcining a product obtained by mixing the gel precursor with an oxidizing agent containing Mn to obtain a composite oxide containing Mn and a metal element M.

[0013] Here, the metal element M is at least one selected from the group consisting of transition metals, rare earth elements, and noble metal elements.

[0014] A composite oxide containing Mn and the metal element M can be obtained by the production method including the above steps 1 and 2, and the composite oxide can be used as a VOC removal catalyst. Because such a VOC removal catalyst is obtained by the production method including steps 1 and 2, it has excellent VOC removal efficiency and can efficiently remove VOCs even at low temperatures.

[0015] (Process 1) Step 1 is a step for obtaining a gel precursor by mixing a raw material containing a metal element M with a gelling agent.

[0016] As described above, the metal element M is at least one selected from the group consisting of transition metals, rare earth elements, and noble metal elements. More specific examples include transition metal elements such as Co, Fe, Ni, Cu, Zn, Ti, V, Zr, Nb, Mo, Ir, Ru, and W; rare earth metal elements such as La, Ce, Pr, Nd, Sm, Eu, Gd, Ho, and Yb; and noble metal elements such as Pt, Rh, Pd, Ag, and Au.

[0017] Among these, in terms of making it easier to obtain a VOC removal catalyst that provides superior VOC removal efficiency, the metal element M is preferably at least one selected from the group consisting of Co, Fe, Ni, Cu, Zn, Ti, V, Zr, Nb, Mo, Ir, Ru, and W, and more preferably Co. Therefore, the composite oxide containing Mn and the metal element M is preferably a composite oxide containing Mn and Co, and particularly preferably a composite oxide of Mn and Co.

[0018] The raw material containing the metal element M is not particularly limited as long as it contains the metal element M, and examples thereof include a solution in which the metal element M alone, a compound of the metal element M, or a mixture thereof is dissolved or dispersed in a solvent.

[0019] The type of compound of metal element M is not particularly limited, and examples thereof include inorganic compounds, chlorides, and organic compounds of metal element M. Examples of inorganic compounds of metal element M include oxides of metal element M, compounds containing oxoanions of metal element M (metallates), nitrates, sulfates, chlorides, chlorates, perchlorates, chloride complexes, carbonates, hydrogencarbonates, phosphates, and hydrogenphosphates of metal element M, and among these, the inorganic compound of metal element M is preferably a nitrate. Examples of organic compounds of metal element M include acetates, oxalates, formates, and succinates.

[0020] Examples of the solvent for the raw material containing the metal element M include water, and other alcohol solvents such as ethanol and isopropanol may also be used, and a mixed solvent of water and alcohol may also be used.

[0021] The raw material containing the metal element M is preferably an aqueous solution of an inorganic compound of the metal element M, more preferably an aqueous solution of a nitrate of the metal element M, and particularly preferably an aqueous solution of cobalt nitrate.

[0022] In the raw material containing the metal element M, the concentration of the metal element M is not particularly limited, and is preferably 0.01 M or more, more preferably 0.05 M or more, even more preferably 0.1 M or more, and is preferably 100 M or less, more preferably 50 M or less, even more preferably 10 M or less, and particularly preferably 5 M or less.

[0023] The gelling agent serves to gel the raw material containing the metal element M. The type of such gelling agent is not particularly limited as long as it can provide a gelling effect, and for example, a wide variety of known gelling agents can be used.

[0024] Examples of gelling agents include starch, and other polysaccharides other than starch, specifically agar, cellulose, etc. The gelling agent may also be an organic acid such as citric acid.

[0025] Starch is a gelling agent that can be preferably used in step 1 because it has a high gelling effect on raw materials containing the metal element M. In particular, when starch is used as a gelling agent, it can also function as a dispersant and a reducing agent in step 2 described below, so that the composite oxide finally obtained has many pores and a low crystallinity, which increases structural defects and tends to improve catalytic activity.

[0026] The type of starch is not particularly limited, and examples thereof include potato starch, wheat starch, rice starch, corn starch, and mung bean starch.

[0027] The amount of gelling agent used is not particularly limited as long as it gels the raw material containing the metal element M. For example, the gelling agent can be used so that the concentration of the gelling agent in the raw material containing the metal element M is 1 to 100 g / L, preferably 5 to 50 g / L, and more preferably 10 to 30 g / L.

[0028] In step 1, the method for mixing the raw material containing the metal element M with the gelling agent is not particularly limited, and for example, mixing can be carried out using a known mixer. The temperature during mixing is also not particularly limited, and is, for example, 15 to 120°C, preferably 20 to 110°C, and more preferably 40 to 100°C.

[0029] In step 1, a raw material containing a metal element M is mixed with a gelling agent, whereby gelation proceeds and a gel precursor is produced.

[0030] (Process 2) In step 2, the gel precursor obtained in step 1 is mixed with an oxidizing agent containing Mn.

[0031] The oxidizing agent containing Mn (hereinafter simply referred to as "oxidizing agent") can be, for example, a wide variety of compounds that contain Mn and have oxidizing properties, and specific examples thereof include permanganates. Among these, the oxidizing agent containing Mn is preferably potassium permanganate (KMnO4, K2MnO4, etc.), and more preferably KMnO4.

[0032] The oxidizing agent used in step 2 may be in the form of a solution, for example, an aqueous solution of the oxidizing agent. The concentration of the oxidizing agent is, for example, 0.01 M or more, more preferably 0.05 M or more, even more preferably 0.1 M or more, and is preferably 100 M or less, more preferably 50 M or less, even more preferably 10 M or less, and particularly preferably 5 M or less.

[0033] In step 2, the gel precursor is mixed with an oxidizing agent, and the gel precursor is etched by the oxidizing agent. Therefore, the product obtained by mixing the gel precursor with the oxidizing agent in step 2 contains an oxide of manganese and an oxide of the metal element M.

[0034] In step 2, the amount of oxidizing agent used is not particularly limited. For example, the number of moles of manganese per mole of metal element contained in the raw material used in step 1 is preferably 0.01 to 100 moles, more preferably 0.05 to 50 moles, even more preferably 0.1 to 10 moles, and particularly preferably 0.5 to 5 moles.

[0035] The product produced by mixing the gel precursor with the oxidizing agent can be recovered by an appropriate method, for example, by known solid-liquid separation such as centrifugation, filtration, etc. The recovered solid can also be washed by an appropriate method.

[0036] The product produced in step 2 is subjected to a calcination treatment, thereby obtaining a composite oxide containing Mn and the metal element M (Mn-based composite oxide).

[0037] The calcination method is not particularly limited, and a wide variety of known calcination methods can be used. For example, the calcination temperature can be 200°C or higher. In addition, the calcination temperature is preferably 600°C or lower, since the crystallinity of the resulting composite oxide tends to be low. The calcination temperature is preferably 250 to 480°C, more preferably 290 to 450°C, and even more preferably 300 to 400°C.

[0038] The firing time may be appropriately selected depending on the firing temperature, and may be, for example, 1.5 to 5 hours. In step 2, the rate of temperature increase during firing is not particularly limited and may be appropriately set, for example, at 1 to 10°C / min.

[0039] The calcination treatment may be carried out in air or in an inert gas atmosphere. Preferably, the calcination treatment is carried out in air. For the calcination treatment, a known heating device such as a commercially available heating furnace can be used.

[0040] By the firing treatment, impurities and the like are removed, and a composite oxide containing high-purity Mn and the metal element M is formed.

[0041] The composite oxide obtained by the production method including the above steps 1 and 2 can be used directly as a VOC removal catalyst, or, if necessary, other additives can be mixed with the composite oxide to produce a VOC removal catalyst. The VOC removal catalyst may be a composite oxide containing Mn and a metal element M alone.

[0042] In particular, when starch is used as a gelling agent in step 1, as described above, the resulting composite oxide has an increased number of pores and a reduced degree of crystallinity, which in turn increases structural defects and tends to improve catalytic activity. As a result, the VOC removal catalyst obtained by using starch as a gelling agent in step 1 has excellent VOC removal efficiency even at lower temperatures. From this perspective, it is preferable that the composite oxide obtained by the production method comprising steps 1 and 2 has an amorphous main phase.

[0043] The manufacturing method of the present invention includes steps 1 and 2, and is particularly characterized by etching a gel precursor gelled using a gelling agent. This allows for the easy production of a catalyst with excellent VOC removal efficiency using only low-toxicity raw materials. While not necessarily limiting, it is believed that the manufacturing method of the present invention includes etching of a gel precursor, and therefore the resulting composite oxide has uniformly dispersed manganese and a metal element M (e.g., cobalt). In particular, the etching target being gel-like makes it easier for the metal element M to disperse, facilitating the uniform dispersion of manganese and the metal element M (e.g., cobalt). As a result, the composite oxide has a high specific surface area and low crystallinity, resulting in many so-called structural defects, providing many oxygen vacancies and active species. It is therefore presumed that the VOC removal catalyst can efficiently remove VOCs even at low temperatures.

[0044] The composite oxide containing Mn and the metal element M produced by the production method of the present invention preferably contains, for example, 1 to 35 mol % of Mn element. In this case, the VOC removal catalyst is likely to have an improved VOC removal efficiency. The composite oxide containing Mn and the metal element M preferably contains 5 to 40 mol % of the metal element M. In this case, the VOC removal catalyst is likely to have an improved VOC removal efficiency. The composite oxide more preferably contains 6 mol % or more of the metal element M, even more preferably 7 mol % or more, and particularly preferably 8 mol % or more, and more preferably 30 mol % or less, and even more preferably 20 mol % or less. The composite oxide containing Mn and the metal element M produced by the production method of the present invention may further contain oxygen derived from the oxide and potassium derived from the oxidizing agent, etc.

[0045] 2.VOC removal catalyst The VOC removal catalyst of the present invention contains a composite oxide containing Mn and a metal element M, where the metal element M is at least one selected from the group consisting of transition metals, rare earth elements, and noble metal elements, and the composite oxide has an amorphous main phase. Such a VOC removal catalyst can be produced, for example, by the production method of the present invention including the above-mentioned steps 1 and 2.

[0046] More specific examples of the metal element M include transition metal elements such as Co, Fe, Ni, Cu, Zn, Ti, V, Zr, Nb, Mo, Ir, Ru, and W; rare earth metal elements such as La, Ce, Pr, Nd, Sm, Eu, Gd, Ho, and Yb; and noble metal elements such as Pt, Rh, Pd, Ag, and Au. Among these, the metal element M is preferably at least one selected from the group consisting of Co, Fe, Ni, Cu, Zn, Ti, V, Zr, Nb, Mo, Ir, Ru, and W, and more preferably Co, in terms of making it easier to obtain a VOC removal catalyst that provides superior VOC removal efficiency.

[0047] The composite oxide has an amorphous main phase, and specifically, the crystalline phase contained in the composite oxide is 10% by mass or less, preferably 5% by mass or less, and more preferably 1% by mass or less. When the composite oxide has an amorphous main phase, the VOC removal catalyst tends to have high VOC removal efficiency even at low temperatures. The fact that the composite oxide has an amorphous main phase can be determined from the XRD spectrum.

[0048] The BET specific surface area of ​​the composite oxide is 80m 2 / g or more is preferable, and 90m 2 / g or more is more preferable, and 95m 2 / g or more is more preferable, and 100m 2 It is particularly preferable that the saturation coefficient is 1 / g or more.

[0049] The VOC removal catalyst of the present invention can be formed solely from the above-mentioned composite oxide, or can contain components other than the above-mentioned composite oxide as long as the effects of the present invention are not impaired.

[0050] The composite oxide preferably contains 1 to 35 mol% of Mn element. In this case, the VOC removal catalyst is likely to have an improved VOC removal efficiency. The composite oxide more preferably contains 5 mol% or more of Mn element, even more preferably 10 mol% or more, particularly preferably 15 mol% or more, more preferably 30 mol% or less, and particularly preferably 25 mol% or less. The composite oxide also preferably contains 5 to 40 mol% of metal element M. In this case, the VOC removal catalyst is likely to have an improved VOC removal efficiency. The composite oxide more preferably contains 6 mol% or more of metal element M, even more preferably 7 mol% or more, particularly preferably 8 mol% or more, more preferably 30 mol% or less, and even more preferably 20 mol% or less.

[0051] The composite oxide contains oxygen in addition to Mn element and metal element M. The oxygen content of the composite oxide is, for example, 50 mol % or more and 70 mol % or less. In addition to Mn element, metal element M, and oxygen, the composite oxide may contain, for example, a metal element (e.g., a metal element such as potassium) derived from the oxidizing agent used during synthesis.

[0052] The composite oxide may be a mixture of an oxide of Mn and an oxide of a metal element M, a composite oxide in which Mn and a metal element M form a solid solution, or a composite oxide in which part of the Mn in the oxide of Mn is replaced with a metal element.

[0053] The composite oxide contained in the VOC removal catalyst of the present invention is, for example, in the form of a powder. The shape of the composite oxide is not particularly limited, and it can be formed into various shapes such as particles, polygons, scales, fibers, and rods, among which nanoparticles are preferred.

[0054] 3.VOC removal method The VOC removal method of the present invention comprises a step of burning VOCs using the above-mentioned VOC removal catalyst or a VOC catalyst obtained by a production method comprising the steps 1 and 2.

[0055] For example, a VOC removal catalyst is placed in a reactor, and VOCs such as toluene are introduced into the reactor and treated at a predetermined temperature to combust the VOCs. This allows the VOCs to be removed. If necessary, a mixed gas of nitrogen and oxygen is introduced into the reactor to combust the VOCs.

[0056] The type of reactor used for VOC removal is not particularly limited, and for example, a wide variety of known reactors used in catalytic combustion of VOCs can be used. The treatment temperature for VOCs in the reactor is not particularly limited, and can be the same as the treatment temperature set for known VOC removal. In particular, in the present invention, by using the above-mentioned VOC removal catalyst, excellent VOC removal efficiency is achieved even at low temperatures. [Example]

[0057] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples.

[0058] Example 1 A nitric acid solution prepared by dissolving 5 mmol of Co(NO3)2·6H2O in 50 mL of deionized water was added to a beaker, and 2 g of potato starch was added. The mixture was stirred at room temperature for 10 minutes, followed by stirring in a 70 °C water bath for 90 minutes, yielding a red gel-like precursor (gelatinous substance). The beaker was then cooled to room temperature (25 °C), and 10 mmol of KMnO4 aqueous solution (40 mL) was added and stirred at room temperature until a black precipitate formed. The resulting black precipitate was washed several times with an ethanol-water mixture, then collected by centrifugation and dried at 60 °C for 12 hours. The black precipitate was then calcined in air at 350 °C for 3 hours to obtain a composite oxide. This composite oxide was designated "MnCoαOβ" and used as a VOC removal catalyst.

[0059] (Comparative Example 1) A nitric acid solution prepared by dissolving 5 mmol of Co(NO3)2·6H2O in 50 mL of deionized water was added to a beaker, and 2 g of potato starch was added. The mixture was stirred at room temperature for 10 minutes, followed by stirring in a 70°C water bath for 90 minutes to obtain a red gel-like precursor (gelatinous substance). The gel-like precursor was dried at 60°C for 12 hours and then calcined in air at 350°C for 3 hours to obtain cobalt oxide. This cobalt oxide was designated "CoOx" and used as a VOC removal catalyst.

[0060] (Comparative Example 2) In a beaker, 2 g of potato starch was dispersed in 50 mL of deionized water and stirred at room temperature for 10 minutes. The beaker was then placed in a 70 °C water bath and stirred for 90 minutes to obtain a gel precursor (gelatinous substance). The beaker was then cooled to room temperature (25 °C), and 10 mmol of KMnO4 aqueous solution (40 mL) was poured into the dispersion and stirred at room temperature until a black precipitate formed. The resulting black precipitate was washed several times with an ethanol-water mixture and then collected by centrifugation and dried at 60 °C for 12 hours. The black precipitate was then calcined in air at 350 °C for 3 hours to obtain the oxide. This oxide was designated "MnOx" and used as a VOC removal catalyst.

[0061] <Evaluation method> (VOC removal test) A toluene removal test was conducted using the VOC removal catalyst obtained in each Example according to the schematic flow shown in Figure 1. In this test, a tubular reactor was filled with the VOC removal catalyst (Catalyst in the figure) sandwiched between quartz wool, and toluene was introduced into the reactor at a predetermined flow rate to cause a reaction, thereby removing the toluene. As shown in Figure 1, the reactor was connected to an oxygen cylinder and a nitrogen cylinder, allowing oxygen and nitrogen to flow into the reactor. The conditions for the toluene removal test were as follows: a glass reactor with an inner diameter of 8 mm was used, the amount of VOC removal catalyst packed therein was 50 mg, and the toluene concentration in the reactor was set to 1,000 ppm by volume. In addition, the flow rate of nitrogen gas used as a carrier into the reactor was set to 35 cm 3 / min, and the nitrogen gas flow rate for toluene introduction was 5cm 3 / min, oxygen gas flow rate 10cm 3The reaction temperature in the reactor was adjusted to various temperatures between 130 and 300°C, and the toluene removal characteristics were evaluated. Sampling was performed three times every 10°C in the 130-200°C range, three times every 5°C in the 200-250°C range, and three times every 10°C in the 260-300°C range. VOC concentrations were measured using a Shimadzu GC-2014 gas chromatograph. The carbon dioxide concentration emitted from the reactor outlet was measured using a HORIBA FG-120 FT-IR gas analyzer.

[0062] Figure 2 shows SEM images of the catalysts obtained in Example 1 and Comparative Examples 1 and 2. The catalyst in Example 1 was in the form of irregular nanoparticles, whereas Comparative Example 1 (CoOx) was composed of irregular flakes and blocks, and Comparative Example 2 (MnOx) was composed of a bulk with a smooth surface.

[0063] Table 1 shows the results of elemental analysis of the catalysts obtained in Example 1 and Comparative Examples 1 and 2 by EDS analysis.

[0064] [Table 1]

[0065] FIG. 3 shows the XRD spectra of the catalysts obtained in Example 1 and Comparative Examples 1 and 2. In the XRD spectra, Comparative Example 1 (CoOx) exhibited a sharp diffraction peak of the Co3O4 phase, while Comparative Example 2 (MnOx) was found to be a multiphase mixture containing MnO2 and K2Mn4O8 phases. On the other hand, MnCoαOβ of Example 1 exhibited a weak diffraction peak of the Co3O4 phase, and no diffraction peaks related to manganese species were observed. This result suggests that the MnCoαOβ of Example 1 contained a large amount of amorphous phase, had a crystallinity of 10% by mass or less, and had many structural defects.

[0066] FIG. 4 shows the results of the VOC removal test using the catalysts obtained in Example 1 and Comparative Examples 1 and 2. Specifically, FIG. 4 is a plot showing the relationship between temperature (X axis) and toluene removal rate (Y axis). The graph in FIG. 4 also shows the 50% decomposition temperature (T 50% ), 90% decomposition temperature (T 90% ), 100% decomposition temperature (T 100% ) value.

[0067] Table 2 summarizes the results of FIG. 4, showing the results of VOC removal tests using the catalysts obtained in Example 1 and Comparative Examples 1 and 2. The results of FIG. 4 and Table 2 indicate that the VOC removal catalysts obtained in each Example have better VOC removal performance than the Comparative Examples. Therefore, it was found that the VOC removal catalysts obtained in each Example can be suitably used as catalysts for catalytic combustion of toluene, a typical VOC substance. In particular, it was found that this depends on the amount of potassium permanganate used in producing the catalyst.

[0068] [Table 2]

Claims

1. A method for producing a VOC removal catalyst, comprising: Step 1: Mixing a raw material containing Co with a gelling agent to obtain a gel precursor; and step 2 of calcining a product obtained by mixing the gel precursor with an oxidizing agent containing Mn to obtain a composite oxide containing Mn and Co. The method for producing the gelling agent is at least one selected from the group consisting of starch, agar, and cellulose.

2. The method of claim 1 , wherein the gelling agent is starch.

3. 3. The method according to claim 1, wherein the composite oxide contains 1 to 35 mol % of Mn element.

4. A method for removing VOCs, comprising a step of decomposing VOCs using the VOC removal catalyst obtained by the production method according to any one of claims 1 to 3.

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