A cerium-phosphorus co-doped calcium lanthanum cobalt perovskite type catalyst, a preparation method and application in thermal catalytic oxidation of toluene

Abstract

This invention discloses a cerium-phosphorus co-doped lanthanum cobalt oxide perovskite catalyst, its preparation method, and its application in the thermocatalytic oxidation of toluene. The catalyst has an ABO3 type perovskite crystal structure and the molecular formula La. 0.92 Ce 0.08 Co 0.96 P 0.04 O3, appearing as black granules, is prepared by: mixing anhydrous ethanol and ultrapure water to form an ethanol-water mixed solution; adding lanthanum salt, cerium salt, cobalt salt, phosphate salt, and citric acid to the mixed solution, stirring, and ultrasonically treating to obtain a sol; stirring the sol in a water bath until a gel forms, and drying to obtain a dry gel; grinding the dry gel into powder, and calcining it in a muffle furnace to obtain a black powdery cerium-phosphorus co-doped lanthanum cobalt oxide perovskite. This invention simplifies the catalyst preparation process, enabling the catalytic oxidation of toluene to form T... 90 The temperature was significantly reduced, effectively filling the gap in the application of metal-nonmetal dual-element doped lanthanum cobalt oxide perovskite in the field of thermocatalytic oxidation of toluene.

Description

Technical Field

[0001] This invention relates to a cerium-phosphorus co-doped lanthanum cobalt oxide perovskite catalyst, its preparation method, and its application in the thermocatalytic oxidation of toluene, belonging to the field of catalyst technology. Background Technology

[0002] With the rapid development of my country's industry, air pollution caused by volatile organic compounds (VOCs) is becoming increasingly serious. Toluene (C7H8), a typical VOC, is a key raw material in the chemical industry for the preparation of dyes, gasoline additives, and other products. However, this substance is highly irritating, acutely toxic, and potentially teratogenic. Direct emission without treatment poses a serious threat to the ecological balance and human health. Thermocatalytic oxidation technology, due to its high energy efficiency and lack of secondary pollution, has become the mainstream technology for the end-of-pipe treatment of VOCs. The performance of the catalyst is the core factor determining the degradation efficiency and application cost of this technology. Currently, catalysts used for the catalytic oxidation of toluene are mainly divided into two categories: precious metal catalysts and non-metallic catalysts. However, both types of catalysts have significant shortcomings: precious metal catalysts, although highly active, face problems such as high cost and easy deactivation due to poisoning by impurities such as sulfur and chlorine; traditional non-metallic catalysts generally suffer from low catalytic efficiency and poor long-term stability.

[0003] Against this backdrop, perovskite catalysts with unique ABO3 crystal and electronic structures have attracted considerable attention in the field of toluene thermocatalytic oxidation due to their advantages such as low cost, structural stability, and environmental friendliness. Among them, lanthanum cobalt oxide (LaCoO3)-based perovskites are a research hotspot, but the TLC (thermal oxidation time) of pure-phase LaCoO3 for toluene oxidation remains a challenge. 90 The temperature at which toluene removal reaches 90% is as high as 300°C or more, and the high reaction temperature significantly increases the energy consumption cost for industrial applications.

[0004] To address this issue, elemental doping modification technology has been widely applied to optimize the catalytic performance of perovskites. For example, there is an acid-modified calcium-doped lanthanum cobalt oxide perovskite catalyst for the thermal catalytic oxidation of toluene and its preparation method (CN109675576B), which prepares calcium-doped lanthanum cobalt oxide perovskite via a sol-gel method and optimizes catalyst performance through citric acid treatment; a method for preparing and applying lanthanum cobalt oxide nanomaterials with A- and B-site cerium and aluminum co-doping to induce oxygen vacancy defects (CN116060017B), which utilizes a citric acid sol-gel method to achieve Ce and Al dual-element doping, inducing oxygen vacancy defects to obtain cerium and aluminum co-doped lanthanum cobalt oxide perovskite nanomaterials for antibacterial purposes; and an erbium-doped lanthanum cobalt oxide photocatalyst powder and its preparation method and application (CN106582667B), which prepares erbium-doped lanthanum cobalt oxide photocatalyst powder through a precipitation-calcination process.

[0005] However, existing technologies still have significant limitations: the core function of the material involved in CN116060017B is antibacterial, but no data on its thermocatalytic activity against volatile organic compounds (VOCs) such as toluene are provided, making it impossible to confirm its applicability in the field of toluene degradation; although Er doping in CN106582667B can regulate the electronic structure in photocatalytic scenarios, high-temperature thermocatalytic conditions may lead to a decrease in structural stability or deactivation of catalytic active sites, making it difficult to meet the application requirements of thermocatalytic oxidation of toluene; CN109675576B requires a two-stage calcination process to prepare the catalyst, which is not only cumbersome but also significantly increases the preparation cost. In summary, existing technologies for the dual-element co-doping modification of lanthanum cobalt oxide perovskite with metals and non-metals, and their specific application in the thermocatalytic oxidation of toluene, are still relatively scarce. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a cerium-phosphorus co-doped lanthanum cobalt oxide perovskite catalyst, its preparation method, and its application in the thermocatalytic oxidation of toluene. It proposes a cerium (metal element)-phosphorus (non-metal element) co-doped lanthanum cobalt oxide perovskite scheme, which not only simplifies the catalyst preparation process but also improves the thermocatalytic oxidation of toluene. 90 The temperature was significantly reduced, effectively filling the gap in the application of metal-nonmetal dual-element doped lanthanum cobalt oxide perovskite in the field of toluene thermocatalytic oxidation, and providing a new approach for the modification and optimization of perovskite-type toluene degradation catalysts.

[0007] To achieve the above objectives, this invention employs a cerium-phosphorus co-doped lanthanum cobalt oxide perovskite catalyst, wherein the catalyst has an ABO3 type perovskite crystal structure and the molecular formula La. 0.92 Ce 0.08 Co 0.96 P 0.04 O3 appears as black granules.

[0008] A second aspect of the present invention also provides a method for preparing the cerium-phosphorus co-doped lanthanum cobalt oxide perovskite catalyst, comprising the following steps:

[0009] 1) Take anhydrous ethanol and ultrapure water, mix them evenly to form an ethanol-water mixed solution; add lanthanum salt, cerium salt, cobalt salt, phosphate salt and citric acid to the mixed solution, stir and sonicate to obtain a sol;

[0010] 2) Stir the sol obtained in step 1) under water bath conditions until a gel is formed, and then dry it to obtain a dry gel;

[0011] 3) Grind the dry gel obtained in step 2) into powder, place it in a muffle furnace and calcine to obtain black powdery cerium-phosphorus co-doped lanthanum cobalt oxide perovskite;

[0012] 4) After pressing, crushing and screening the black powder obtained in step 3), the target catalyst is obtained.

[0013] As an improvement, in step 1), the molar ratio of lanthanum salt, cerium salt, cobalt salt, and phosphate salt is (5-10):(0.5-1):(5-10):(0.2-0.6), and the molar ratio of the total metal cations to citric acid is 1:(1-2).

[0014] As an improvement, the molar ratio of lanthanum salt, cerium salt, cobalt salt, and phosphate salt is 9.2:0.8:9.6:0.4, and the molar ratio of the total metal cations to citric acid is 1:1.1.

[0015] As an improvement, the lanthanum salt is La(NO3)3·6H2O, the cerium salt is Ce(NO3)3·6H2O, the cobalt salt is Co(NO3)2·6H2O, and the phosphate salt is NH4H2PO4.

[0016] As an improvement, the total duration of ultrasonic treatment in step 1) is 10-20 min, and the ultrasonic power is 100-300 W.

[0017] As an improvement, in step 2), the water bath temperature is 75°C and the stirring time is 3 hours; the drying temperature is 180°C and the drying time is 3 hours.

[0018] As an improvement, in step 3), the calcination heating rate is 5℃ / min, the calcination temperature is 750℃, and the calcination time is 5h.

[0019] A third aspect of the present invention also provides the application of the cerium-phosphorus co-doped lanthanum cobalt oxide perovskite catalyst, or the cerium-phosphorus co-doped lanthanum cobalt oxide perovskite catalyst prepared by the preparation method, in the thermocatalytic oxidation of toluene.

[0020] As an improvement, the application conditions are: toluene concentration of 1000 ppm, total flow rate of reaction gas of 100 mL / min, and reaction gas being a mixture of dry air and nitrogen; and / or, the catalyst catalyzes the oxidation of toluene at a T0. 50 The temperature is 251℃, T 90 The temperature is 253℃; and / or the reaction products of catalytic oxidation of toluene are only CO2 and H2O.

[0021] The principle of this invention:

[0022] The core principle of thermocatalytic oxidation of toluene is to lower the activation energy of the reaction through a catalyst, achieving efficient mineralization of toluene under low-temperature conditions of 200-500℃. The entire process follows a four-step cycle of adsorption, activation, oxidation, and desorption. Gaseous toluene molecules and O2 molecules in the reaction gas are adsorbed onto active sites on the catalyst surface (such as metal cations and oxygen vacancies) through physical or chemical interactions. Electrons are transferred from the active center of the catalyst to the toluene molecules, polarizing the benzene ring and methyl groups and lowering the bond breaking energy. At the same time, O2 is activated into lattice oxygen and surface-adsorbed oxygen, among other active species. The activated toluene first undergoes methyl oxidation (converting sequentially to hydroxyl, aldehyde, and carboxyl groups), then undergoes C=C bond cleavage of the benzene ring to generate small molecule intermediates, and is finally completely oxidized to CO2 and H2O. After product desorption, the active sites are regenerated, and the process enters the next cycle. Compared with direct incineration, this process can reduce the reaction temperature by more than 300℃ and produces no secondary pollutants such as dioxins. The core reliance is on the catalyst's activation ability for the reactants and the efficiency of active oxygen supply.

[0023] Existing technologies only employ single-element doping schemes targeting a single lattice site in perovskite. Even though some studies have reported the use of dual-element co-doped lanthanum cobalt oxide perovskite for preparing antibacterial nanomaterials, their core function remains focused on antibacterial applications, lacking practical application and performance verification in the thermal catalytic oxidation of toluene. This invention achieves highly efficient catalysis through cerium (Ce) and phosphorus (P) co-doped lanthanum cobalt oxide perovskite catalysts via synergistic regulation of dual doping and an enhanced oxygen vacancy cycling mechanism. Its core logic stems from the structural modulation and electronic optimization of the ABO3 lattice. A-site Ce... 3+ Replace La 3+ Inducing lattice distortion, B-site P 5+ Replace Co 3+ This leads to charge-compensated oxygen vacancies, and the two work synergistically to induce oxygen vacancy formation and increase the number of active sites; Ce's Ce 3+ ↔Ce 4+ The reversible Redox cycle mediates oxygen activation and regeneration, and P promotes Co through electronic regulation. 2+ Towards highly active Co 3+ The conversion simultaneously enhances toluene adsorption capacity and inhibits Co ion sintering, while oxygen vacancies act as channels to accelerate reactive oxygen migration, forming a highly efficient reactive oxygen cycle. This mechanism supports the catalyst's high activity at low temperatures (T0). 90 This invention offers advantages such as high stability and no secondary pollution, with a temperature range of 253℃. It also utilizes Ce / P dual-element co-doping at the A / B sites to construct a novel synergistic catalysis and oxygen cycle enhancement mechanism.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] 1. Through synergistic doping modification with cerium (a metallic element) and phosphorus (a non-metallic element), the crystal and electronic structures of lanthanum cobalt oxide perovskite were significantly optimized, inducing the formation of abundant oxygen vacancies and enhancing reactive oxygen cycle. This resulted in the catalyst exhibiting outstanding low-temperature activity in the thermocatalytic oxidation of toluene. Under conditions of 1000 ppm toluene concentration and 100 mL / min total reaction gas flow rate, the toluene removal rate reached 50% at the temperature (T0). 50 The temperature at which the removal rate reaches 90% is only 251℃ (T). 90 The temperature is as low as 253℃, compared to pure phase LaCoO3 (T 90 (>300℃) Significantly reduces reaction temperature, substantially lowers energy consumption costs for industrial applications, and solves the core problem of high catalytic temperature in traditional perovskite catalysts.

[0026] 2. P with P 5+ P-doping replaces Co sites, causing lattice distortion due to differences in ionic radius and valence state. The Co-O bond length shortens after P doping, increasing the bulk Co³⁺ proportion (active sites) and promoting oxygen vacancy formation. This leads to the redox cycle of Ce. 3+ ↔Ce 4+ It ensures the regeneration and structural stability of the active center. Under the same conditions, after two repeated catalytic tests, the catalyst did not show deactivation and has the ability to operate continuously for a long time. It overcomes the defects of traditional non-metallic catalysts being prone to deactivation and precious metal catalysts being prone to poisoning, and reduces the replacement cost and maintenance difficulty in industrial applications.

[0027] 3. The reaction products of catalytic oxidation of toluene are only CO2 and H2O, with no secondary pollutants generated. This avoids the risk of intermediate toxic products or secondary pollution generated during the degradation of toluene, meeting the environmental protection requirements of "no secondary pollution" and conforming to the green development concept of current air pollution control.

[0028] 4. The preparation method is based on citric acid sol-gel, which has clear process steps, simple operation, no need for complex equipment and harsh reaction conditions, and is easy to scale up. The raw materials used are all common chemical raw materials, which are inexpensive and easy to obtain. Compared with precious metal catalysts, the preparation cost is greatly reduced, and it has significant industrial application and promotion value.

[0029] 5. A modification strategy of co-doping lanthanum cobalt oxide perovskite with metal (Ce) and non-metal (P) was proposed. The catalytic performance was optimized by synergistic regulation of A-site and B-site, which filled the research gap of this type of doping in the application of toluene thermocatalytic oxidation in the existing technology, and provided a new technical idea and reference direction for the performance optimization of perovskite catalysts. Attached Figure Description

[0030] Figure 1This is a flowchart illustrating the preparation process of the cerium-phosphorus co-doped lanthanum cobalt oxide perovskite catalyst of the present invention.

[0031] Figure 2 The X-ray diffraction (XRD) patterns of Example 1 (undoped pure phase lanthanum cobalt perovskite), Example 2 (cerium-phosphorus co-doped lanthanum cobalt perovskite), Example 3 (cerium-doped lanthanum cobalt perovskite), and Example 4 (phosphorus-doped lanthanum cobalt perovskite).

[0032] Figure 3 The thermocatalytic oxidation of toluene is evaluated using the catalysts of Examples 1 to 4 (undoped, cerium-phosphorus co-doped, cerium-doped, and phosphorus-doped lanthanum cobalt perovskite) as curves (represented by the change in toluene conversion rate as a function of reaction temperature). Detailed Implementation

[0033] The following embodiments are further illustrations of the present invention and serve as explanations of the technical content of the present invention. However, the essence of the present invention is not limited to the embodiments described below. Those skilled in the art can and should know that any simple changes or substitutions based on the spirit of the present invention should fall within the protection scope claimed by the present invention.

[0034] All raw materials used in this embodiment are commercially available analytical grade reagents, without further purification processing.

[0035] Lanthanum salt: Lanthanum nitrate hexahydrate (La(NO3)3·6H2O, purity ≥99.99%).

[0036] Cerium salt: Cerium nitrate hexahydrate (Ce(NO3)3·6H2O, purity ≥99.99%).

[0037] Cobalt salt: Cobalt nitrate hexahydrate (Co(NO3)2·6H2O, purity ≥99.99%).

[0038] Phosphate salt: Ammonium dihydrogen phosphate (NH4H2PO4, purity ≥99.99%).

[0039] Complexing agent: Citric acid (purity ≥ 99.8%);

[0040] Solvents: Anhydrous ethanol (purity ≥ 99.7%), ultrapure water (resistivity ≥ 18.2 MΩ·cm).

[0041] Example 1

[0042] A method for preparing undoped pure-phase lanthanum cobalt oxide perovskite catalyst (LaCoO3) includes the following steps:

[0043] 1) Measure 40 mL of anhydrous ethanol and 20 mL of ultrapure water at a volume ratio of 2:1 and place them in a 100 mL beaker. Stir magnetically for 2-3 min at room temperature to form a homogeneous ethanol-water mixture. Add 4.33 g of La(NO3)3·6H2O and 2.91 g of Co(NO3)2·6H2O to the mixture and continue stirring magnetically until the solids are completely dissolved. Then, sonicate for 10 min (ultrasonic power 200 W, frequency 40 kHz). Next, add 4.56 g of citric acid (total metal cations to citric acid molar ratio 1:1.1) to the solution, continue stirring magnetically and sonicating for 10 min until a sol is formed, then stop the treatment.

[0044] 2) Place the beaker containing the sol in a constant temperature water bath, control the water bath temperature at 75℃, and stir magnetically at 300r / min for 3 hours. The sol will gradually dehydrate and concentrate to form a viscous gel. Transfer the gel to a ceramic boat and place it in an electric constant temperature oven to dry at 180℃ for 3 hours to remove the solvent and water of crystallization, thus obtaining a loose dry gel (precursor).

[0045] 3) Place the dry gel in an agate mortar and grind it into a uniform powder; transfer the powder to a corundum crucible, place it in a muffle furnace, heat it to 750°C at a heating rate of 5°C / min, and calcine it at a constant temperature for 5 hours; after calcination, cool it to room temperature with the furnace to obtain a black powdery pure phase lanthanum cobalt perovskite.

[0046] 4) Press the above black powder into tablets at a pressure of 10 MPa on a tablet press. After the tablets are crushed in a crusher, they are screened through a standard sieve to obtain 40-60 mesh particles, which is sample 1 (undoped pure phase LaCoO3 catalyst).

[0047] Example 2

[0048] Combination Figure 1 As shown, the cerium-phosphorus co-doped lanthanum cobalt oxide perovskite catalyst (La 0.92 Ce 0.08 Co 0.96 P 0.04 The preparation method of O3 includes the following steps:

[0049] 1) Accurately measure 40 mL of anhydrous ethanol and 20 mL of ultrapure water at a volume ratio of 2:1, place them in a 100 mL beaker, and magnetically stir for 2-3 min at room temperature to form a mixed solution; add 3.98 g La(NO3)3·6H2O, 0.347 g Ce(NO3)3·6H2O, 2.79 g Co(NO3)2·6H2O, and 0.046 g NH4H2PO4 to the mixed solution, and magnetically stir until the solid is completely dissolved. Then sonicate for 10 min (ultrasonic power 200 W, frequency 40 kHz); then add 4.56 g citric acid (the molar ratio of the total metal cations to citric acid is 1:1.1), continue stirring and sonicating for 10 min to form a sol;

[0050] 2) Subsequent steps (gel preparation, drying, calcination, tableting and screening) were exactly the same as in Example 1, ultimately yielding Sample 2 (cerium-phosphorus co-doped La). 0.92 Ce 0.08 Co 0.96 P 0.04 O3 catalyst, 40-60 mesh black granules.

[0051] Example 3

[0052] Cerium-doped lanthanum cobalt oxide perovskite catalyst (La 0.95 Ce 0.05 The preparation method of CoO3 includes the following steps:

[0053] 1) Accurately measure 40 mL of anhydrous ethanol and 20 mL of ultrapure water at a volume ratio of 2:1, place them in a 100 mL beaker, and magnetically stir for 2-3 min at room temperature to form a mixed solution; add 4.11 g La(NO3)3·6H2O, 0.217 g Ce(NO3)3·6H2O, and 2.91 g Co(NO3)2·6H2O to the mixed solution, and magnetically stir until the solids are completely dissolved. Then sonicate for 10 min (ultrasonic power 200 W, frequency 40 kHz); then add 4.56 g citric acid (the molar ratio of the total metal cations to citric acid is 1:1.1), continue stirring and sonicating for 10 min to form a sol;

[0054] 2) Subsequent steps (gel preparation, drying, calcination, tableting and screening) were exactly the same as in Example 1, ultimately yielding Sample 3 (cerium-doped La). 0.95 Ce 0.05 CoO3 catalyst, 40-60 mesh black granules.

[0055] Example 4

[0056] Phosphorus-doped lanthanum cobalt oxide perovskite catalyst (LaCo) 0.96 P 0.04The preparation method of O3 includes the following steps:

[0057] 1) Accurately measure 40 mL of anhydrous ethanol and 20 mL of ultrapure water at a volume ratio of 2:1, place them in a 100 mL beaker, and magnetically stir for 2-3 min at room temperature to form a mixed solution; add 4.33 g La(NO3)3·6H2O, 2.79 g Co(NO3)2·6H2O, and 0.046 g NH4H2PO4 to the mixed solution, and magnetically stir until the solid is completely dissolved. Then sonicate for 10 min (ultrasonic power 200 W, frequency 40 kHz); then add 4.56 g citric acid (the molar ratio of the total metal cations to citric acid is 1:1.1), continue stirring and sonicating for 10 min to form a sol;

[0058] 2) Subsequent steps (gel preparation, drying, calcination, tableting and screening) were exactly the same as in Example 1, ultimately yielding Sample 4 (phosphorus-doped LaCo). 0.96 P 0.04 O3 catalyst, 40-60 mesh black granules).

[0059] Sample performance testing and result analysis:

[0060] 1. X-ray diffraction (XRD) characterization

[0061] X-ray diffraction (XRD) characterization analysis was performed on the four catalyst samples prepared in Examples 1-4. The testing instrument was an X-ray diffractometer, and the characterization results are shown in Figure 2. Figure 2 As can be seen, no impurity peaks appeared in the XRD patterns of samples 2 (cerium-phosphorus co-doped), 3 (cerium-doped), and 4 (phosphorus-doped), and all characteristic diffraction peaks were consistent with lanthanum cobalt oxide perovskite (LaCoO3), indicating that the pure-phase structure of doped lanthanum cobalt oxide perovskite was successfully synthesized. At the same time, the characteristic diffraction peaks of samples 2-4 showed a slight shift compared with sample 1 (undoped pure phase). This phenomenon is due to the lattice distortion of perovskite ABO3 caused by the doping of Ce and P elements, which further confirms that Ce and P elements have been successfully embedded in the lanthanum cobalt oxide lattice, rather than existing as impurities.

[0062] 2. Evaluation of the activity of thermocatalytic oxidation of toluene

[0063] The catalytic performance of samples 1-4 was evaluated using a fixed-bed reactor, and the specific test conditions are as follows:

[0064] The catalyst dosage was 0.1 g, the reaction gas was a mixture of dry air and nitrogen (toluene concentration 1000 ppm), the total gas flow rate was 100 mL / min, the reaction temperature range was 20-400℃, and the conversion rate of toluene was indicated by online detection of CO2 concentration using an infrared gas analyzer.

[0065] Catalytic activity evaluation results are as follows Figure 3 As shown (expressed as a curve of toluene conversion versus reaction temperature): To of toluene catalytic oxidation of sample 1 (undoped pure phase LaCoO3) 90 The temperature at which 90% conversion is achieved is 306℃; the temperature of sample 3 (cerium single-doped) is... 90 The temperature was 274℃; the T value of sample 4 (phosphorus single-doped) was... 90 The temperature was 285℃; while sample 2 (cerium-phosphorus co-doped La) 0.92 Ce 0.08 Co 0.96 P 0.04 O3) T 90 As low as 253℃, T 50 The temperature at which the conversion rate reaches 50% is 251℃, and the catalytic activity is significantly better than that of the pure phase and single-doped samples. In addition, the product detection results show that the final products of the catalytic oxidation of toluene in all samples are only CO2 and H2O, and no other toxic and harmful intermediate products were detected, indicating that the catalyst has good mineralization ability and no risk of secondary pollution.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A cerium-phosphorus co-doped lanthanum cobalt oxide perovskite catalyst, characterized in that, The catalyst has an ABO3 type perovskite crystal structure and the molecular formula La. 0.92 Ce 0.08 Co 0.96 P 0.04 O3 appears as black granules.

2. A method for preparing a cerium-phosphorus co-doped lanthanum cobalt oxide perovskite catalyst as described in claim 1, characterized in that, Includes the following steps: 1) Take anhydrous ethanol and ultrapure water, mix them evenly to form an ethanol-water mixed solution; add lanthanum salt, cerium salt, cobalt salt, phosphate salt and citric acid to the mixed solution, stir and sonicate to obtain a sol; 2) Stir the sol obtained in step 1) under water bath conditions until a gel is formed, and then dry it to obtain a dry gel; 3) Grind the dry gel obtained in step 2) into powder, place it in a muffle furnace and calcine to obtain black powdery cerium-phosphorus co-doped lanthanum cobalt oxide perovskite; 4) After pressing, crushing and screening the black powder obtained in step 3), the target catalyst is obtained.

3. The preparation method of the cerium-phosphorus co-doped lanthanum cobalt oxide perovskite catalyst as described in claim 2, characterized in that, In step 1), the molar ratio of lanthanum salt, cerium salt, cobalt salt, and phosphate salt is (5-10):(0.5-1):(5-10):(0.2-0.6), and the molar ratio of the total metal cations to citric acid is 1:(1-2).

4. The preparation method of the cerium-phosphorus co-doped lanthanum cobalt oxide perovskite catalyst as described in claim 3, characterized in that, The molar ratio of lanthanum salt, cerium salt, cobalt salt, and phosphate salt is 9.2:0.8:9.6:0.4, and the molar ratio of the total metal cations to citric acid is 1:1.

1.

5. The method for preparing a cerium-phosphorus co-doped lanthanum cobalt oxide perovskite catalyst as described in claim 2 or 3, characterized in that, The lanthanum salt is La(NO3)3·6H2O, the cerium salt is Ce(NO3)3·6H2O, the cobalt salt is Co(NO3)2·6H2O, and the phosphate salt is NH4H2PO4.

6. The method for preparing a cerium-phosphorus co-doped lanthanum cobalt oxide perovskite catalyst as described in claim 2, characterized in that, The total duration of ultrasonic treatment in step 1) is 10-20 minutes, and the ultrasonic power is 100-300W.

7. The method for preparing a cerium-phosphorus co-doped lanthanum cobalt oxide perovskite catalyst as described in claim 2, characterized in that, In step 2), the water bath temperature is 75℃ and the stirring time is 3h; the drying temperature is 180℃ and the drying time is 3h.

8. The method for preparing a cerium-phosphorus co-doped lanthanum cobalt oxide perovskite catalyst as described in claim 2, characterized in that, In step 3), the heating rate of calcination is 5℃ / min, the calcination temperature is 750℃, and the calcination time is 5h.

9. The application of the cerium-phosphorus co-doped lanthanum cobalt oxide perovskite catalyst according to claim 1, or the cerium-phosphorus co-doped lanthanum cobalt oxide perovskite catalyst prepared by any one of claims 2-8, in the thermal catalytic oxidation of toluene.

10. The application as described in claim 9, characterized in that, The application conditions are: toluene concentration of 1000 ppm, total flow rate of reaction gas of 100 mL / min, and reaction gas being a mixture of dry air and nitrogen; and / or, the catalyst catalyzes the oxidation of toluene at a T0.

05. 50 The temperature is 251℃, T 90 The temperature is 253℃; and / or the reaction products of catalytic oxidation of toluene are only CO2 and H2O.

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