阅读说明：本技术 一种La1-xMn1+xO3的制备方法 (La1-xMn1+xO3Preparation method of (1) ) 是由 司文哲 丁云 彭悦 陈建军 马永亮 李俊华 于 2021-09-07 设计创作，主要内容包括：本发明提供一种La-(1-x)Mn-(1+x)O-(3)催化剂的制备方法,其包括以下步骤：将镧盐、锰盐以及非离子型表面活性剂溶于溶剂中,得到前驱体溶液；对所述前驱体溶液进行干燥,得到粘性固体；对所述粘性固体进行煅烧,得到La-(1-x)Mn-(1+x)O-(3)催化剂；其中,0≤x<1。本发明的La-(1-x)Mn-(1+x)O-(3)催化剂的制备方法简单易行,原料易于获取,操作方便,适合大批量生产。进一步地,本发明制备的La-(1-x)Mn-(1+)-(x)O-(3)催化剂具备优异的催化氧化挥发性有机物的性能。(The invention provides La 1‑x Mn 1+x O 3 A method for preparing a catalyst comprising the steps of: dissolving lanthanum salt, manganese salt and a non-ionic surfactant in a solvent to obtain a precursor solution; drying the precursor solution to obtain a viscous solid; calcining the viscous solid to obtain La 1‑x Mn 1+x O 3 A catalyst; wherein x is more than or equal to 0<1. La of the invention 1‑x Mn 1+x O 3 The preparation method of the catalyst is simple and easy to implement, the raw materials are easy to obtain, the operation is convenient, and the method is suitable forAnd (4) mass production. Further, La prepared by the present invention 1‑x Mn 1+ x O 3 The catalyst has excellent performance of catalyzing and oxidizing volatile organic compounds.)

1. La_1-xMn_1+xO₃The preparation method of the catalyst is characterized by comprising the following steps:

dissolving lanthanum salt, manganese salt and a non-ionic surfactant in a solvent to obtain a precursor solution;

drying the precursor solution to obtain a viscous solid;

calcining the viscous solid to obtain La_1-xMn_1+xO₃A catalyst;

wherein x is more than or equal to 0 and less than 1.

2. The method according to claim 1, wherein the precursor solution is prepared by a method comprising the steps of:

dissolving lanthanum salt and manganese salt in a first solvent to obtain a first mixed solution;

dissolving a nonionic surfactant in a second solvent to obtain a second mixed solution;

mixing the first mixed solution and the second mixed solution to obtain a precursor solution; wherein the first solvent and the second solvent are different.

3. The production method according to claim 2, wherein the first solvent is water; and/or, the second solvent is an alcohol solvent; preferably, the alcohol solvent comprises one or a combination of two or more of ethanol, n-propanol, isopropanol, n-pentanol, isopentanol, n-hexanol, and isohexane glycol.

4. The method according to any one of claims 1 to 3, wherein the lanthanum salt is one or a combination of two or more of lanthanum nitrate, lanthanum sulfate, lanthanum acetate or lanthanum chloride; the manganese salt is one or the combination of more than two of manganese nitrate, manganese sulfate, manganese acetate and manganese chloride.

5. The method according to any one of claims 1 to 4, wherein the nonionic surfactant comprises one or a combination of two or more of alkylolamides, alkylamine polyoxyethylene ethers, and alkylamines.

6. The method according to any one of claims 1 to 5, wherein the molar ratio of the manganese salt to the nonionic surfactant is 1 to 3: 2.

7. The method according to any one of claims 1 to 6, wherein the drying temperature is 60 to 100 ℃ and the drying time is 6 to 8 hours.

8. The method as claimed in any one of claims 1 to 7, wherein the calcination is carried out by raising the temperature to 500-700 ℃ at a temperature-raising rate of 1-5 ℃/min.

9. The method according to any one of claims 1 to 8, wherein the calcination is carried out for 4 to 6 hours; and/or, the calcination is carried out under an air atmosphere.

10. La prepared by the preparation method according to any one of claims 1 to 9_1-xMn_1+xO₃The catalyst is used for catalyzing and oxidizing volatile organic compounds, preferably toluene compounds.

Technical Field

The invention relates to La_1-xMn_1+xO₃In particular to a catalyst La applied to the catalytic oxidation of volatile organic compounds_1-xMn_1+xO₃The preparation method belongs to the technical field of air pollution control.

Background

Volatile Organic Compounds (VOCs) are one of the major atmospheric pollutants today and are important precursors to the tropospheric secondary pollutant ozone and Secondary Organic Aerosols (SOA). Volatile organic compounds are air pollutants that form photochemical reactions with the atmosphere, and are represented by: toluene, xylene, ethyl acetate, and the like. Part of volatile organic compounds in the organic solvent can also cause harm to human health, environment and the like. This is because the release of volatile organic compounds in large quantities in the environment promotes the generation of photochemical smog, greenhouse effect, etc. through reactions, and the particles and ozone in photochemical smog seriously affect the immune system, respiratory system, reproductive system, etc., and most seriously may cause health problems such as cancer and mutation.

At present, the means for controlling the discharge of VOCs are mainly divided into two types, one type is to recycle VOCs by a physical method, for example: activated carbon adsorption, condensation recovery and the like; another class is oxidative breakdown of VOCs into non-toxic or less toxic substances by destructive methods. Among them, the catalytic oxidation method is concerned about because it does not produce secondary pollution, has high removal rate and low reaction temperature.

Among them, the commercial catalysts mainly include noble metals and non-noble metals, and perovskite catalysts have certain superiority in thermal stability, chemical stability and structural stability, and thus have been the focus of research by researchers. Perovskite-type metal oxides have different physicochemical properties (such as redox behavior, oxygen mobility, electronic and ionic conductivity) due to their compositional and structural variability, have been widely studied over the past several decades, and have been used in various fields. It is well known that the catalytic activity of perovskite-type metal oxides is related to their physicochemical properties, including morphology, specific surface area, pore structure and oxygen non-stoichiometry.

In recent years, various methods of synthesizing perovskite metal oxides (soft-film plate method, hydrothermal method, combustion method, sol-gel method, coprecipitation method, molten salt method, etc.) have been successively reported to improve their physicochemical properties, thereby improving their catalytic activities. However, the reaction temperature of the traditional perovskite type metal oxide for catalyzing and oxidizing the toluene is above 300 ℃, which is higher than that of the noble metal catalyst; therefore, how to reduce the temperature of the reaction for catalyzing and oxidizing the toluene by the perovskite type catalyst is a technical problem at present.

Citation 1 describes the preparation of LaMnO by a sol-gel method using citric acid complexation₃It was observed that it exhibited good catalytic activity for the oxidation of VOCs (acetone, isopropanol and benzene). Citation 2 adopts citric acid complexation-hydrothermal synthesis combined method to prepare polycrystalline cubic or rhombohedral phase perovskite type oxide La_1-xSr_xMO_3-δ(M ═ Co, Mn; x ═ 0, 0.4) spherical nanoparticles, which are catalytically active for the oxidation of typical VOCs (ethyl acetate and toluene). However, cited document 1 requires the use of citric acid to prepare a catalyst having low catalytic activity and a reaction temperature of 300 ℃ or higher at which the perovskite-type metal oxide catalyzes the oxidation of toluene. The cited document 2 requires not only the use of citric acid for the preparation of the catalyst but also the preparation of the crystal phase, and therefore, the preparation method is too complicated to be popularized, and the reaction temperature of the perovskite-type metal oxide for the catalytic oxidation of toluene is also above 300 ℃.

Reference 3 discloses a method for producing a perovskite-type composite metal oxide catalyst having MO_y/LaMO₃And (5) structure. The preparation method of the catalyst comprises the following steps: (1) mixing the raw materials according to the molar ratio of La to M of 1: 0.8-1: 1.2, loading the mixture on a carrier according to a sol-gel method, loading the mixture on the carrier by an impregnation method or carrying out a coprecipitation methodOne of (1); (2) mixing deionized water, acid and potassium permanganate according to a proportion to prepare acidic potassium permanganate solutions with different concentrations; (3) then the LaMO prepared in the step (1) is added₃The perovskite type material is dipped in an acidic potassium permanganate solution; (4) and (4) washing and drying the material obtained in the step (3) by using distilled water or deionized water. The catalyst prepared by the above preparation method can remove toluene, and the preparation method is too complicated and the catalyst component is complicated.

Cited documents:

cited document 1: J.Urban et al, NanoLetters,2004,4,1547-

Cited document 2: niu et al, Catalysis Today 2007,126,420

Cited document 3: CN109364915A

Disclosure of Invention

Problems to be solved by the invention

In view of the technical problems in the prior art, the present invention firstly provides a La_1-xMn_1+xO₃The preparation method of the catalyst is simple and easy to implement, the raw materials are easy to obtain, and the operation is convenient.

La prepared by the preparation method of the invention_1-xMn_1+xO₃The catalyst can be applied to catalytic oxidation of volatile organic compounds.

Means for solving the problems

[1]La_1-xMn_1+xO₃A method for preparing a catalyst comprising the steps of:

dissolving lanthanum salt, manganese salt and a non-ionic surfactant in a solvent to obtain a precursor solution;

drying the precursor solution to obtain a viscous solid;

calcining the viscous solid to obtain La_1-xMn_1+xO₃A catalyst;

wherein x is more than or equal to 0 and less than 1.

[2] The production method according to the above [1], wherein the production method of the precursor solution comprises the steps of:

dissolving lanthanum salt and manganese salt in a first solvent to obtain a first mixed solution;

dissolving a nonionic surfactant in a second solvent to obtain a second mixed solution;

mixing the first mixed solution and the second mixed solution to obtain a precursor solution; wherein the first solvent and the second solvent are different.

[3] The production method according to the above [2], wherein the first solvent is water; and/or, the second solvent is an alcohol solvent; preferably, the alcohol solvent comprises one or a combination of two or more of ethanol, n-propanol, isopropanol, n-pentanol, isopentanol, n-hexanol, and isohexane glycol.

[4] The production method according to any one of the above [1] to [3], wherein the lanthanum salt is one or a combination of two or more of lanthanum nitrate, lanthanum sulfate, lanthanum acetate, and lanthanum chloride; the manganese salt is one or the combination of more than two of manganese nitrate, manganese sulfate, manganese acetate and manganese chloride.

[5] The production method according to any one of the above [1] to [4], wherein the nonionic surfactant includes one or a combination of two or more of alkylolamide, alkylamine polyoxyethylene ether, and alkylamine.

[6] The production method according to any one of the above [1] to [5], wherein the molar ratio of the manganese salt to the nonionic surfactant is 1 to 3: 2.

[7] The production method according to any one of the above [1] to [6], wherein the drying temperature is 60 to 80 ℃ and the drying time is 6 to 8 hours.

[8] The preparation method according to any one of the above [1] to [7], wherein the calcination is performed by heating to 500-700 ℃ at a heating rate of 1-5 ℃/min.

[9] The production method according to any one of the above [1] to [8], wherein the calcination is carried out for 4 to 6 hours; and/or, the calcination is carried out under an air atmosphere.

[10]A method according to the above [1]]-[9]The production method of any one ofLa thus obtained_1-xMn_1+xO₃The catalyst is used for catalyzing and oxidizing volatile organic compounds, preferably toluene compounds.

ADVANTAGEOUS EFFECTS OF INVENTION

La of the invention_1-xMn_1+xO₃The preparation method of the catalyst is simple and easy to implement, the raw materials are easy to obtain, the operation is convenient, and the catalyst is suitable for mass production.

Further, La prepared by the present invention_1-xMn_1+xO₃The catalyst has excellent performance of catalyzing and oxidizing volatile organic compounds.

Drawings

FIG. 1 shows LaMnO prepared in example 1 of the present invention₃XRD contrast patterns obtained for the catalyst and comparative example 1.

FIG. 2 shows LaMnO of example 1 of the present invention₃And (4) a catalyst reaction performance graph.

FIG. 3 shows LaMnO prepared in comparative example 1₃And (4) a catalyst reaction performance graph.

FIG. 4 shows LaMnO prepared in comparative example 2₃And (4) a catalyst reaction performance graph.

Detailed Description

The present invention will be described in detail below. The technical features described below are explained based on typical embodiments and specific examples of the present invention, but the present invention is not limited to these embodiments and specific examples. It should be noted that:

in the present specification, the numerical range represented by "numerical value a to numerical value B" means a range including the end point numerical value A, B.

In the present specification, "plural" in "plural", and the like means a numerical value of 2 or more unless otherwise specified.

In this specification, the terms "substantially", "substantially" or "substantially" mean an error of less than 5%, or less than 3% or less than 1% as compared to the relevant perfect or theoretical standard.

In the present specification, "%" denotes mass% unless otherwise specified.

In the present specification, the meaning of "may" includes both the meaning of performing a certain process and the meaning of not performing a certain process.

In this specification, "optional" or "optionally" means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not.

In the present specification, reference to "some particular/preferred embodiments," "other particular/preferred embodiments," "embodiments," and the like, means that a particular element (e.g., feature, structure, property, and/or characteristic) described in connection with the embodiment is included in at least one embodiment described herein, and may or may not be present in other embodiments. In addition, it is to be understood that the described elements may be combined in any suitable manner in the various embodiments.

The invention firstly provides La_1-xMn_1+xO₃A method for preparing a catalyst comprising the steps of:

dissolving lanthanum salt, manganese salt and a non-ionic surfactant in a solvent to obtain a precursor solution;

drying the precursor solution to obtain a viscous solid;

calcining the viscous solid to obtain La_1-xMn_1+xO₃A catalyst;

wherein x is more than or equal to 0 and less than 1.

Inventive La of the invention_1-xMn_1+xO₃The catalyst is prepared by dissolving lanthanum salt, manganese salt and non-ionic activator in solvent to form precursor solution, and drying to form viscous solid; then calcining at high temperature to prepare La_1-xMn_1+xO₃A catalyst. The preparation method is simple and feasible, raw materials are easy to obtain, mass production is easy to realize, and the prepared La_1-xMn_1+xO₃The catalyst has high catalytic activity.

The value of x is not particularly limited in the present invention, and can be selected as needed. For example, x can be 0, 0.1, 0.3, 0.5, 0.7, 0.9, etc.

The manner in which the lanthanum salt, manganese salt and nonionic surfactant are dissolved in the solvent is not particularly limited, and the mixing may be performed in any feasible manner. As the solvent, an alcohol solvent, specifically an alcohol water solvent having a certain concentration, may be used in the present invention. The concentration of the alcohol-based aqueous solvent is not particularly limited in the present invention, and may be selected as needed. Further, the alcohol solvent of the present invention may include one or a combination of two or more of ethanol, n-propanol, isopropanol, n-pentanol, isopentanol, n-hexanol, isohexanediol, and the like.

Further, in some specific embodiments, the method for preparing the precursor solution comprises the following steps:

dissolving lanthanum salt and manganese salt in a first solvent to obtain a first mixed solution;

dissolving a nonionic surfactant in a second solvent to obtain a second mixed solution;

mixing the first mixed solution and the second mixed solution to obtain a precursor solution; wherein the first solvent and the second solvent are different.

In some specific embodiments, after dissolving the lanthanum salt and the manganese salt in the first solvent, stirring, ultrasound, etc. may be used to rapidly dissolve the lanthanum salt and the manganese salt, and to disperse them uniformly. After the nonionic surfactant is dissolved in the second solvent, stirring, ultrasonic treatment, etc. may be also used to dissolve the nonionic surfactant quickly and disperse the nonionic surfactant uniformly.

Further, after the first mixed solution and the second mixed solution are mixed, the first mixed solution and the second mixed solution can be uniformly mixed by adopting stirring, ultrasonic waves and the like. Preferably, stirring is used to obtain the precursor solution. Specifically, the stirring time may be 30-40 min, for example: 32min, 35min, 37min, 39min and the like.

In some specific embodiments, the present inventionSaid first solvent is water; and/or, the second solvent is an alcohol solvent. Considering La_1-xMn_1+xO₃The alcohol solvent of the present invention preferably includes one or a combination of two or more of ethanol, n-propanol, isopropanol, n-pentanol, isopentanol, n-hexanol, isohexanediol, and the like. The amount of the alcohol solvent used is not particularly limited in the present invention, as long as the nonionic surfactant can be dissolved.

The lanthanum salt and manganese salt in the present invention are not particularly limited, and may be some of those commonly used in the art. In some embodiments, the lanthanum salt can be one or a combination of two or more of lanthanum nitrate, lanthanum nitrite, lanthanum sulfate, lanthanum sulfite, lanthanum acetate, lanthanum chloride, or the like; for example: the lanthanum salt can be one or the combination of more than two of lanthanum nitrate, lanthanum sulfate, lanthanum acetate or lanthanum chloride; the manganese salt is one or more of nitrate, nitrite, sulfate, sulfite, acetate or chloride of manganese.

The present invention is not particularly limited as far as it can achieve the functions of the present invention, with respect to the nonionic surfactant. Further, the present invention preferably uses alkylolamides, alkylamine polyoxyethylene ethers, alkylamines as nonionic surfactants, thereby enabling further improvement of La_1-xMn_1+xO₃Catalytic activity of the catalyst.

For alkylolamides, the formula can be represented as:

R₁CONH_m(R₂OH)_2-m

wherein R is₁Is a hydrocarbon group having 8 or more carbon atoms, preferably a hydrocarbon group having 8 to 20 carbon atoms; r₂Alkyl of 6 or less carbon atoms, preferably 1 to 4 carbon atoms; m is 0 or 1.

In general, the hydrocarbyl group may be an alkyl group, an alkenyl group, or the like.

Specifically, the R is₁May be one of coconut oil base, dodecyl and the likeIn the formula (I) and R₂May be one of methyl, ethyl, propyl, isopropyl, etc.

For example, the alkylolamides may be one or a combination of two or more of coconut diethanolamide, coconut monoethanolamide, lauryl diethanolamide, lauryl monoisopropanolamide, and the like.

For alkylamine polyoxyethylene ethers, the formula can be:

wherein R is an alkyl group with more than 8 carbon atoms, preferably an alkyl group with 8-20 carbon atoms; x and y can be natural numbers in the range of 5-50, and preferably natural numbers in the range of 10-40.

Specifically, the R may be one of cocoyl, dodecyl, octadecyl, and the like.

For example, the alkylamine polyoxyethylene ether may be one or a combination of two or more of coconut amine polyoxyethylene ether, lauryl amine polyoxyethylene ether, octadecyl amine polyoxyethylene ether, and the like.

For alkylamines, the formula may be:

R’NH₂

wherein R' is an alkyl group having 8 or more carbon atoms, preferably an alkyl group having 8 to 20 carbon atoms.

Specifically, the R' may be one of cocoyl, dodecyl, tetradecyl, hexadecyl, octadecyl, and the like.

For example, the alkylamine can be one or a combination of two or more of cocoamine, dodecylamine, tetradecylamine, hexadecylamine, octadecylamine, and the like.

In addition, to further improve the La of the present invention_1-xMn_1+xO₃In the present invention, it is preferable not to use a hydroxyl chelating agent such as Citric Acid (CA), Tartaric Acid (TA) or Gluconic Acid (GA) for the catalytic activity of the catalyst.

In some specific embodiments, the manganese saltAnd the molar ratio of the nonionic surfactant to the nonionic surfactant is 1-3: 2. When the molar ratio of the manganese salt to the nonionic surfactant is 1-3: 2, La with excellent performance can be prepared_{1- x}Mn_1+xO₃A catalyst.

In the present invention, a viscous solid is obtained by drying. In some embodiments, to facilitate the preparation of La_1-xMn_1+xO₃And in the drying procedure, the drying temperature is 60-100 ℃, for example: 65 ℃, 70 ℃, 75 ℃, 80 ℃, 85 ℃, 90 ℃, 95 ℃ and the like, wherein the drying time is 6-8h, such as: 6.5h, 7h, 7.5h and the like.

In the present invention, La is obtained by a calcination process_1-xMn_1+xO₃Catalysts, in some embodiments, to obtain La with superior performance_1-xMn_1+xO₃A catalyst, wherein in the calcining step, the temperature is raised to 500-700 ℃ at the heating rate of 1-5 ℃/min for calcining; and the calcining time is 4-6 h. Specifically, the temperature rise rate may be 1.5 ℃/min, 2 ℃/min, 2.5 ℃/min, 3 ℃/min, 3.5 ℃/min, 4 ℃/min, 4.5 ℃/min, or the like; the calcining temperature can be 520 ℃, 540 ℃, 560 ℃, 580 ℃, 600 ℃, 620 ℃, 650 ℃, 680 ℃ and the like; the calcining time is 4.2h, 4.4h, 4.6h, 4.8h, 5h, 5.2h, 5.4h, 5.6h, 5.8h and the like. Further, in the present invention, the calcination may be performed under an air atmosphere.

The invention also provides La prepared by the preparation method_1-xMn_1+xO₃The catalyst is used for catalyzing and oxidizing volatile organic compounds, preferably toluene compounds.

Examples

Embodiments of the present invention will be described in detail below with reference to examples, but those skilled in the art will appreciate that the following examples are only illustrative of the present invention and should not be construed as limiting the scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available.

Example 1

LaMnO₃-1 preparation of the catalyst

Firstly, weighing 4mmol of lanthanum nitrate and 4mmol of manganese nitrate, dissolving the lanthanum nitrate and the manganese nitrate in 10mL of aqueous solution, stirring to form a clear solution A, weighing 8mmol of hexadecylamine, dissolving the hexadecylamine in 50mL of ethanol solution, and stirring to form a clear solution B; and (3) dropwise adding the clear solution A into the clear solution B, and stirring for 30min to form a mixed solution C (namely a precursor solution). Then drying in an oven at 65 ℃ for 6h to obtain a viscous solid; finally, in the air atmosphere, the temperature is raised to 600 ℃ at the temperature rise rate of 5 ℃/min and calcined for 5h, thereby obtaining LaMnO₃。

Example 2

Firstly, weighing 4mmol of lanthanum nitrate and 4mmol of manganese nitrate, dissolving the lanthanum nitrate and the manganese nitrate in 10mL of aqueous solution, stirring to form a clear solution A, weighing 8mmol of hexadecylamine, dissolving the hexadecylamine in 50mL of isopropanol solution, and stirring to form a clear solution B; and (3) dropwise adding the clear solution A into the clear solution B, and stirring for 30min to form a mixed solution C (namely a precursor solution). Then drying in an oven at 65 ℃ for 6h to obtain a viscous solid; finally, in the air atmosphere, the temperature is raised to 600 ℃ at the temperature rise rate of 5 ℃/min and calcined for 5h, thereby obtaining LaMnO₃。

Example 3

Firstly, weighing 4mmol of lanthanum nitrate and 4mmol of manganese nitrate, dissolving the lanthanum nitrate and the manganese nitrate in 10mL of aqueous solution, stirring to form a clear solution A, weighing 8mmol of hexadecylamine, dissolving the hexadecylamine in 50mL of n-hexanol solution, and stirring to form a clear solution B; and (3) dropwise adding the clear solution A into the clear solution B, and stirring for 30min to form a mixed solution C (namely a precursor solution). Then drying in an oven at 65 ℃ for 6h to obtain a viscous solid; finally, in the air atmosphere, the temperature is raised to 600 ℃ at the temperature rise rate of 5 ℃/min and calcined for 5h, thereby obtaining LaMnO₃。

Comparative example 1

LaMnO₃Preparation of the catalyst

Firstly, 4mmol of lanthanum nitrate and 4mmol of manganese nitrate are weighed and dissolved in 10mL of aqueous solution, and the solution is formed in a stirring wayB, clarifying the solution A, weighing 8mmol of citric acid again, dissolving the citric acid in 50mL of ethanol solution, and stirring to form a clarified solution B; and (4) dropwise adding the clear solution A into the clear solution B, and stirring for 30min to form a mixed solution C. Continuing stirring until the solution forms sol gel, then foaming in a 70 ℃ oven, finally heating to 700 ℃ at the heating rate of 5 ℃/min in the air atmosphere, and calcining for 5h to obtain LaMnO₃。

Comparative example 2

Firstly weighing 8mmol of ethylenediamine, dissolving the ethylenediamine in 50ml of ethanol solution, uniformly stirring, adding 4mmol of lanthanum nitrate and 4mmol of manganese nitrate into the solution, continuously stirring for 1h, transferring the solution into an evaporation dish, and drying the solution in an oven at 70 ℃ for 18 h. Finally calcining the mixture for 2.5 hours in a muffle furnace at 750 ℃ in air atmosphere to obtain LaMnO₃。

Performance testing

1. XRD test

FIG. 1 shows LaMnO of example 1 of the present invention₃Catalyst and LaMnO prepared in comparative example 1₃XRD patterns of the catalysts, LaMnO of example 2 and example 3₃The XRD pattern of the catalyst was substantially the same as in the examples. As can be seen from FIG. 1, LaMnO of the present invention₃LaMnO containing active component in catalyst₃And cubic LaMnO is shown in the figure₃Characteristic peak (JCPDS card No.75-440), under the synthetic method, the LaMnO with better crystal form is successfully synthesized₃No other metal oxides are formed.

2. Catalytic oxidation of toluene experiment

0.1g of LaMnO of examples 1 to 3 and comparative examples 1 and 2 were taken₃The catalysts were tested separately. Specifically, LaMnO of examples 1 to 3 and comparative examples 1 and 2₃The catalysts were placed in a continuous flow fixed bed reactor, the composition of the reaction gas comprises 1000ppm toluene in terms of mass percent, the flow rate of the reaction gas is 100mL/min, the volume space velocity is 60000 mL/(g.h), and the corresponding toluene conversion rates of the catalysts at different temperatures were tested at reaction temperatures of 150 ℃ and 300 ℃, respectively, and the results are shown in FIG. 2, FIG. 3 and FIG. 4.

As can be seen from FIGS. 2, 3 and 4, LaMnO of the present invention₃Catalyst for catalyzing toluene T_90％Preparation of LaMnO for citric acid method of comparative example 1 at 250 ℃ or lower₃Catalyst reaction performance diagram, catalytic toluene oxidation T_90％Preparation of LaMnO with ethylenediamine chelating agent of comparative example 2 at about 272 deg.C₃Catalyst reaction performance diagram, catalytic toluene oxidation T_90％Is about 260 deg.c.

Thus, the LaMnO of the present invention₃The catalyst is LaMnO₃As an active ingredient, catalytic oxidation of toluene can be achieved. And, as can be seen from FIGS. 2, 3 and 4, LaMnO prepared by the preparation method of the present invention₃Compared with the traditional citric acid sol-gel method or the ethylenediamine chelating agent method, the catalyst has excellent performance of catalyzing toluene oxidation, and the preparation method is simple and easy to implement and convenient to operate.

Industrial applicability

The LaMnO provided by the invention₃The catalyst can be industrially prepared and applied as a catalyst for catalyzing and oxidizing volatile organic compounds, in particular for catalyzing and oxidizing toluene compounds.

Having described embodiments of the present invention, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen in order to best explain the principles of the embodiments, the practical application, or improvements made to the technology in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.