A catalyst for catalytic combustion of chlorine-containing multi-component VOCs reaction and its preparation method and application

Abstract

The present invention relates to the technical field of environmental protection and environmental pollution control, and specifically to a catalyst for catalytic combustion of chlorine-containing multi-component VOCs reaction, and a preparation method and application thereof. The catalyst Ru / Co3O4@CeO2-MOF adopts a core-shell structure, which includes the following components in weight percentage: 2.5% to 5% of Co3O4 as the inner core; 93% to 97% of CeO2-MOF as the sub-outer layer; and 0.5% to 2% of Ru in the outermost layer; the present invention adopts a Ru / Co3O4@CeO2-MOF catalyst prepared by layered orderly construction, which enriches the surface acid sites and oxygen vacancies of the catalyst, significantly improves the anti-poisoning performance and redox ability of the catalyst, and enhances the activity, durability and stability of the catalyst. At the same time, the preparation method is simple and easy, and the reaction conditions are mild.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental protection and environmental pollution control, and in particular to a catalyst for catalytic combustion of chlorine-containing multi-component VOCs reaction, and a preparation method and application thereof. Background Art

[0002] The emission of industrial VOCs mainly exists in key industrial sectors such as industrial coating, electronic manufacturing, and construction; the VOCs emitted by these industries usually contain multiple components such as benzene, ketones, and esters. These VOCs are also accompanied by a large number of more toxic chlorinated VOCs (CVOCs), including chlorobenzene, dichloromethane, trichloromethane, trichloroethylene, and tetrachloroethylene. The environmental risks are huge, and some substances have obvious teratogenic, carcinogenic, and mutagenic effects. Therefore, the demand for the treatment of chlorinated multi-component VOCs is becoming more and more urgent. The catalytic combustion technology can be used to decompose VOCs into CO2 and H2O by flameless combustion on the surface of the catalyst. The catalytic combustion temperature is usually between 200℃ and 500℃, which is much lower than the temperature of direct combustion, greatly reducing the reaction energy consumption and producing less toxic byproducts. Catalytic combustion technology has the advantages of high safety factor, low cost, and high purification efficiency. The key factor of catalytic combustion technology is to develop catalysts with low temperature, high efficiency, stable performance, and low price.

[0003] At present, the research on catalysts mainly focuses on precious metal catalysts, metal oxide catalysts, perovskite catalysts and solid acid catalysts. Fukun Bi et al. prepared Pd / ZrO2-C by impregnation method. After adding dichloromethane during toluene oxidation, the toluene conversion rate dropped from 99% to 80%, and the conversion rate could not be restored after cutting off dichloromethane, and irreversible deactivation occurred (Environmental Science&Technology, 2022, 56(23): 17321-17330). M Scharfe et al. showed that Cl in CeO2 supplements the corresponding oxygen vacancies, which will increase the selectivity for chlorinated species and reduce the selectivity for carbon oxides (ACS Catalysis, 2018, 8(4): 2651-2663). Dai et al. used nitrate as a precursor to prepare cerium oxide catalyst by thermal decomposition method for catalytic combustion of trichloroethylene (TCE). The catalytic activity of CeO2 catalyst decreased significantly with the occurrence of reaction operation time, T 50%The value increased from 165℃ to 325℃ (Applied Catalysis B: Environmental, 2008, 81(3-4): 192-202). The catalyst is deactivated due to poor catalytic activity, insufficient deep oxidation capacity, the production of toxic byproducts, or the chlorination reaction of chloride ions with metals or metal oxides. In addition, under the conditions of multi-component VOCs, competition for active sites, differences in molecular diameter, shape and size, and the strength of interaction will significantly affect the adsorption behavior and process of a single VOC on the adsorbent. Therefore, the simultaneous catalytic combustion of chlorine-containing multi-component VOCs places higher demands on the catalytic activity and stability of the catalyst. Summary of the invention

[0004] In view of the shortcomings of existing catalysts, one of the objectives of the present invention is to provide a catalyst for catalytic combustion of chlorine-containing multi-component VOCs, which has high catalytic activity and stability.

[0005] The second object of the present invention is to provide a method for preparing the above catalyst, which is stable and reliable, has mild reaction conditions, and can obtain the above catalyst.

[0006] The third object of the present invention is to provide an application of the above-mentioned catalyst in the simultaneous catalytic combustion of chlorine-containing multi-component VOCs reaction. Experimental results show that the catalyst provided in this application has high catalytic activity, good durability and stability for the simultaneous catalytic combustion of chlorine-containing multi-component VOCs reaction.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] One of the schemes of the present invention is to provide a catalyst for catalytic combustion of chlorine-containing multi-component VOCs, which comprises the following components in weight percentage:

[0009] Co3O42.5%~5%;

[0010] CeO2-MOF 93%~97%;

[0011] Ru0.5%~2%.

[0012] As a preferred technical solution, the catalyst Ru / Co3O4@CeO2-MOF adopts a core-shell structure, which includes the following components in weight percentage:

[0013] Co3O4 2.5% to 5% as the inner core;

[0014] CeO2-MOF as the sub-outer layer is 93% to 97%;

[0015] and the outermost layer of Ru0.5% to 2%;

[0016] Preferably, the catalyst Ru / Co3O4@CeO2-MOF comprises the following components in weight percentage:

[0017] Co3O4 as the core 3.2%~4.5%;

[0018] CeO2-MOF as the sub-outer layer is 94% to 96%;

[0019] And the outermost layer of Ru0.8%~1.5%.

[0020] As other preferred technical solutions, the catalyst Ru-Co / CeO2-MOF, which includes CeO2-MOF as a core, and Co3O4 and Ru supported on the CeO2-MOF, includes the following components in weight percentage:

[0021] Co3O42.5%~5%;

[0022] CeO2-MOF 93%~97%;

[0023] Ru0.5%~2%;

[0024] Preferably, the catalyst Ru-Co / CeO2-MOF comprises the following components in weight percentage:

[0025] Co3O43.2%~4.5%;

[0026] CeO2-MOF 94%~96%;

[0027] Ru0.8%~1.5%.

[0028] The metal oxides derived from MOFs used in the present invention not only have adjustable structures and superior physical and chemical properties, but also can effectively regulate the spatial structure of the catalyst through composite metal oxides Ru and Co3O4, so that the acid sites and redox ability of the catalyst are improved, thereby improving the activity, durability and stability of the catalyst.

[0029] Another embodiment of the present invention is to provide a method for preparing the above-mentioned catalyst for catalytic combustion of chlorine-containing multi-component VOCs reaction. The catalyst Ru / Co3O4@CeO2-MOF is prepared by layered orderly construction, which includes the following steps: adding Co3O4 to water, and then adding CeO2-MOF thereto, stirring evenly, and then dropping RuCl3 solution in a water bath at 70°C to 80°C, continuing to stir for 3h to 5h to volatilize H2O, drying the obtained solid at 80°C to 120°C for 8h to 24h, and then calcining at 300°C to 500°C for 1h to 6h.

[0030] As a preferred technical solution, the Co3O4 described in the above catalyst preparation method is prepared by a hydrothermal method, and the specific method is: dissolve (CH3CO2)2Co in water, add urea under stirring, and after the addition, stir vigorously for 1h to 5h, transfer to a hydrothermal kettle, react at 80℃ to 150℃ for 8h to 24h, filter and wash to neutrality, and then dry the resulting precipitate at 80℃ to 120℃ for 8h to 24h to obtain;

[0031] Preferably, the specific method is to dissolve (CH3CO2)2Co in water, add urea under stirring, the mass ratio of (CH3CO2)2Co, water and urea is 1.25:10-40:0.3, stir vigorously for 1.5h-2.5h after the addition, transfer to a hydrothermal kettle, react at 90℃-110℃ for 10h-14h, filter and wash to neutrality, and then dry the obtained precipitate at 100℃-110℃ for 10h-14h.

[0032] As a preferred technical solution, the CeO2-MOF described in the above catalyst preparation method is prepared by in-situ pyrolysis of Ce-MOF. The specific method is: heat a mixed solution containing 1,3,5-benzenetricarboxylic acid, H2O and ethanol to 50°C~70°C, add Ce(NO3)3·6H2O aqueous solution to the above mixed solution under vigorous stirring, continue to stir vigorously for 0.5h~1.5h, filter and collect the precipitate, wash it with ethanol and deionized water several times, react at 80°C~110°C for 8h~24h, and calcine at 300°C~500°C for 1h~4h to obtain.

[0033] The present invention adopts layered orderly construction to prepare the core-shell Ru / Co3O4@CeO2-MOF catalyst. During the preparation process, the spatial positions of Ru and Co3O4 are orderly configured, so that a strong interaction is formed between the inner core Co3O4 and the carrier CeO2-MOF, and the noble metal active component Ru is not easily lost at high temperature, thereby ensuring that the core-shell Ru / Co3O4@CeO2-MOF catalyst has better activity, durability and stability.

[0034] Ru / Co3O4@CeO2-MOF catalyst has abundant surface acid sites (especially weak and medium-strong acid sites), surface adsorbed oxygen and oxygen vacancy density. Ru / Co3O4@CeO2-MOF catalyst can catalyze the combustion of toluene and chlorobenzene at a relatively low reaction temperature (in a mixed atmosphere of toluene and chlorobenzene, the reaction temperatures for toluene and chlorobenzene to achieve a conversion rate of more than 90% are 219°C and 248°C, respectively).

[0035] Another embodiment of the present invention is to provide a preparation method of the above-mentioned catalyst for catalytic combustion of chlorine-containing multi-component VOCs reaction, wherein the catalyst Ru-Co / CeO2-MOF is prepared by a hydrothermal method, and the specific method is: (CH3CO2)2Co·4H2O is added to H2O, and a RuCl3 solution is added dropwise under stirring. After stirring evenly, the CeO2-MOF is immersed in the above-mentioned solution, and the stirring is continued for 3h to 5h, and then the CeO2-MOF is transferred to an autoclave, and the reaction is carried out at 95℃ to 105℃ for 10h to 14h, and the reaction is carried out naturally after cooling. After that, the catalyst is taken out, and the stirring is continued for 3h to 5h in a water bath at 70℃ to 80℃, and then the H2O is volatilized by continuous stirring. The obtained solid is dried at 100℃ to 120℃ for 10h to 14h, and calcined at 350℃ to 450℃ for 3h to 5h.

[0036] Another embodiment of the present invention is to provide a method for preparing the catalyst for catalytic combustion of chlorine-containing multi-component VOCs reaction. The specific method is: add (CH3CO2)2Co·4H2O to H2O, drop RuCl3 solution into it under stirring, stir evenly, immerse CeO2-MOF in the above solution, continue stirring in a 70℃~80℃ water bath for 3h~5h, then continue stirring to volatilize H2O, dry the obtained solid at 100℃~120℃ for 10h~14h, and calcine at 350℃~450℃ for 3h~5h.

[0037] As a preferred technical solution, the CeO2-MOF described in the above catalyst preparation method is prepared by in-situ pyrolysis of Ce-MOF. The specific method is: heat a mixed solution containing 1,3,5-benzenetricarboxylic acid, H2O and ethanol to 50°C to 70°C, add Ce(NO3)3·6H2O aqueous solution to the above mixed solution under vigorous stirring, continue to stir vigorously for 0.5h to 1.5h, filter and collect the precipitate, wash it with ethanol and deionized water several times, react at 95°C to 105°C for 10h to 14h, and calcine at 350°C to 450°C for 0.5h to 2h to obtain the product.

[0038] The present invention provides two different preparation methods of Ru-Co / CeO2-MOF catalysts. Experiments show that the Ru-Co / CeO2-MOF catalysts prepared by the two methods have good activity, durability and stability, and the Ru-Co / CeO2-MOF catalyst prepared by the hydrothermal method has higher activity in the simultaneous catalytic combustion of toluene and chlorobenzene.

[0039] The present invention also provides the use of the above catalyst or the catalyst obtained by the above preparation method in the catalytic combustion of chlorine-containing multi-component VOCs reaction;

[0040] Preferably, the catalytic reaction conditions are: the concentration of toluene is 800ppm-1200ppm, the concentration of chlorobenzene is 100ppm-400pm, and the reaction space velocity is 10000mL·g -1 ·h -1 ~20000mL·g -1 ·h -1 .

[0041] Preferably, the catalytic reaction conditions are: the concentration of toluene is 1000 ppm, the concentration of chlorobenzene is 250 ppm, and the reaction space velocity is 15000 mL·g -1 ·h -1 .

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] 1. The metal oxides derived from MOFs used in the present invention not only have adjustable structures and better physical and chemical properties, but also can effectively regulate the spatial structure of the catalyst through the composite metal oxides Ru and Co3O4, so that the acid sites and redox ability of the catalyst are improved, thereby improving the activity, durability and stability of the catalyst.

[0044] 2. The present invention adopts layered and orderly construction to prepare the core-shell Ru / Co3O4@CeO2-MOF catalyst. During the preparation process, the spatial positions of Ru and Co3O4 are orderly configured, and a strong interaction is formed between the inner core Co3O4 and the carrier CeO2-MOF. In addition, the noble metal active component Ru is not easily lost at high temperature, thereby ensuring that the core-shell Ru / Co3O4@CeO2-MOF catalyst has better activity, durability and stability.

[0045] 3. The core-shell Ru / Co3O4@CeO2-MOF catalyst provided in this application has abundant surface acid sites (especially weak and medium-strong acid sites), surface adsorbed oxygen and oxygen vacancy density.

[0046] 4. The core-shell Ru / Co3O4@CeO2-MOF catalyst prepared by the present invention can catalyze the combustion of toluene and chlorobenzene at a relatively low reaction temperature (in a mixed atmosphere of toluene and chlorobenzene, the reaction temperatures for toluene and chlorobenzene to achieve a conversion rate of more than 90% are 219°C and 248°C, respectively). BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 X-ray diffraction patterns of the catalysts in Examples 1-4 and Comparative Example 1;

[0048] Figure 2 The Raman spectra of the catalysts in Examples 1-4 and Comparative Example 1 are shown;

[0049] Figure 3 The ammonia temperature-programmed desorption spectra of the catalysts in Examples 1-4 and Comparative Example 1 are shown;

[0050] Figure 4 The hydrogen temperature-programmed reduction spectra of the catalysts in Examples 1-4 and Comparative Example 1;

[0051] Figure 5 The oxygen temperature-programmed desorption spectra of the catalysts in Examples 1-4 and Comparative Example 1 are shown;

[0052] Figure 6 It is the catalytic efficiency diagram of the catalyst in Examples 1-4 and Comparative Example 1; Figure 6 In the figure, A and B are the toluene catalytic efficiency diagrams when the catalysts in Examples 1-4 and Comparative Example 1 simultaneously catalyze toluene + chlorobenzene; C and D are the chlorobenzene catalytic efficiency diagrams when the catalysts in Examples 1-4 and Comparative Example 1 simultaneously catalyze toluene + chlorobenzene. DETAILED DESCRIPTION

[0053] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. The described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0054] The methods are conventional methods unless otherwise specified, and the raw materials can be obtained from public commercial channels unless otherwise specified.

[0055] Example 1

[0056] (1) The designed composition and weight percentage of the core-shell Ru / Co3O4@CeO2-MOF catalyst are:

[0057] Ru (outermost layer) 1 wt%

[0058] Co3O4(core) 4 wt%

[0059] CeO2-MOF (sub-outer layer) 95 wt%

[0060] (2) Preparation of inner core Co3O4: Dissolve 1.25 g (CH3CO2)2Co·4H2O in 20 ml H2O, add 0.3 g urea under stirring, stir vigorously for 2 h after adding urea, then transfer to a hydrothermal kettle, react in an oven at 100°C for 12 h, filter and wash until neutral, and then dry the resulting precipitate at 105°C for 12 h.

[0061] (3) Preparation of the sub-outer layer CeO2-MOF: A solution containing 2.1 g of 1,3,5-benzenetricarboxylic acid, 10 mL of H2O, and 10 mL of ethanol was heated to 60°C. 45 mL of deionized water containing 4.34 g of Ce(NO3)3·6H2O was added to the above solution under vigorous stirring. After continuing to stir vigorously for 1 h, the precipitate was collected by filtration and washed several times with ethanol and deionized water. Finally, the yellow solid was dried at 105°C for 12 h and calcined at 400°C in air for 1.5 h.

[0062] (4) Preparation of core-shell Ru / Co3O4@CeO2-MOF catalyst: 0.08 g Co3O4 was added to 20 ml H2O, and then 1.9 g CeO2-MOF carrier was added. After stirring evenly, 0.02 g Ru (prepared in advance with 0.02 g Ru mL -1 The obtained solid was dried at 105°C for 12 h and calcined in air at 400°C for 4 h to obtain a catalyst.

[0063] Example 2

[0064] (1) The designed composition and weight percentage of the core-shell Ru / CeO2-MOF@Co3O4 catalyst are:

[0065] Ru (outermost layer) 1 wt%

[0066] Co3O4 (outer layer) 4 wt%

[0067] CeO2-MOF (core) 95 wt%

[0068] (2) Preparation of CeO2-MOF core: A solution containing 2.1 g of 1,3,5-benzenetricarboxylic acid, 10 mL of H2O, and 10 mL of ethanol was heated to 60°C. 45 mL of deionized water containing 4.34 g of Ce(NO3)3·6H2O was added to the above solution under vigorous stirring. After continuing to stir vigorously for 1 h, the precipitate was collected by filtration and washed several times with ethanol and deionized water. Finally, the yellow solid was dried at 105°C for 12 h and calcined at 400°C in air for 1.5 h.

[0069] (3) Preparation of CeO2-MOF@Co3O4: 0.27 g (CH3CO2)2Co·4H2O was dissolved in 20 ml H2O, 1.9 g CeO2-MOF was added, and 0.06 g urea was added under stirring. After adding urea, the suspension was vigorously stirred for 2 h and then transferred to an autoclave, and then reacted at 100 °C for 12 h. The precipitate was filtered and washed to neutrality, and then dried at 105 °C for 12 h.

[0070] (4) Preparation of core-shell Ru / CeO2-MOF@Co3O4 catalyst: CeO2-MOF@Co3O4 was immersed in 20 ml H2O, stirred evenly, and then 0.02 g Ru (prepared in advance with 0.02 g Ru mL -1 The obtained solid was dried at 105°C for 12 h and calcined in air at 400°C for 4 h to obtain a catalyst.

[0071] Example 3

[0072] (1) The designed composition and weight percentage of the coated Ru-Co / CeO2-MOF-C catalyst are:

[0073] Ru (outer layer) 1 wt%

[0074] Co (outer layer) 4 wt%

[0075] CeO2-MOF (support) 95 wt%

[0076] (2) Preparation of CeO2-MOF carrier: A solution containing 2.1 g of 1,3,5-benzenetricarboxylic acid, 10 mL of H2O and 10 mL of ethanol was heated to 60°C. 45 mL of deionized water containing 4.34 g of Ce(NO3)3·6H2O was added to the above solution under vigorous stirring. After continuing to stir vigorously for 1 h, the precipitate was collected by filtration and washed several times with ethanol and deionized water. Finally, the yellow solid was dried at 105°C for 12 h and calcined at 400°C in air for 1.5 h.

[0077] (3) Preparation of coated Ru-Co / CeO2-MOF-C catalyst: 0.27 g (CH3CO2)2Co·4H2O was dissolved in 20 mlH2O, and 0.02 g Ru (prepared in advance with 0.02 g Ru·mL -1After stirring evenly, 1.9 g of the CeO2-MOF carrier was immersed in the above solution, and the stirring was continued in a 75°C water bath for 4 h. After continuous stirring to evaporate the H2O, the obtained solid was dried at 105°C for 12 h and calcined in air at 400°C for 4 h to obtain a catalyst.

[0078] Example 4

[0079] (1) The designed composition and weight percentage of the highly dispersed Ru-Co / CeO2-MOF-D catalyst are:

[0080] Ru (dispersed) 1 wt%

[0081] Co (dispersed) 4 wt%

[0082] CeO2-MOF (support) 95 wt%

[0083] (2) Preparation of CeO2-MOF carrier: A solution containing 2.1 g of 1,3,5-benzenetricarboxylic acid, 10 mL of H2O and 10 mL of ethanol was heated to 60°C. 45 mL of deionized water containing 4.34 g of Ce(NO3)3·6H2O was added to the above solution under vigorous stirring. After continuing to stir vigorously for 1 h, the precipitate was collected by filtration and washed several times with ethanol and deionized water. Finally, the yellow solid was dried at 105°C for 12 h and calcined at 400°C in air for 1.5 h.

[0084] (3) Preparation of highly dispersed Ru-Co / CeO2-MOF-D catalyst: 0.27 g (CH3CO2)2Co·4H2O was dissolved in 20 ml H2O, and 0.02 g Ru (prepared in advance with 0.02 g Ru·mL -1 RuCl3 solution), stirred evenly, immersed 1.9 g of the carrier CeO2-MOF in the above solution, continued stirring for 4 h, transferred to an autoclave, placed in an oven at 100°C for hydrothermal treatment for 12 h, took out after natural cooling, continued stirring in a water bath at 75°C for 4 h, continued stirring to volatilize H2O, dried the solid at 105°C for 12 h, and calcined in air at 400°C for 4 h to obtain a catalyst.

[0085] Comparative Example

[0086] Preparation of CeO2-MOF: A solution containing 2.1 g of 1,3,5-benzenetricarboxylic acid, 10 mL of H2O, and 10 mL of ethanol was heated to 60°C. 45 mL of deionized water containing 4.34 g of Ce(NO3)3·6H2O was added to the above solution under vigorous stirring. After vigorous stirring for 1 h, the precipitate was collected by filtration and washed several times with ethanol and deionized water. Finally, the yellow solid was dried at 105°C for 12 h and calcined at 400°C in air for 1.5 h.

[0087] Test example

[0088] The phase structure of the catalysts obtained in Examples 1-4 and the comparative example was tested by X-ray diffraction (XRD) and Raman spectroscopy (Raman). The XRD pattern of the material was obtained on a powder diffractometer (PANalytical BV, Netherlands) using Cu Kα radiation in the 2θ range of 10-80°C. Raman was collected on a HORIBA Scientific LabRAM HR Evolution. The phase structure results of the obtained catalyst are as follows: Figure 1 and Figure 2 shown.

[0089] from Figure 1 From the XRD patterns, it can be seen that Ru and Co3O4 species are successfully configured on the catalyst in all embodiments of the present invention. Figure 2 The Raman spectrum shows that the configuration of Ru and Co3O4 causes the distortion of CeO2-MOF lattice. XRD and Raman results show that all embodiments have good metal-metal interactions.

[0090] The surface acidity characteristics of the catalysts obtained in Examples 1-4 and the comparative example were tested by ammonia temperature programmed desorption test (NH3-TPD). The test method is as follows: the catalyst (100 mg) was pretreated and heated at a flow rate of 5 vol.% NH3 / Ar (30 ml·min -1 ) at 10℃·min -1 The surface acidity characteristics of the catalyst obtained are as follows: Figure 3 As shown:

[0091] from Figure 3 It can be seen that the core-shell Ru / Co3O4@CeO2-MOF in Example 1 of the present invention has a weak acid content (Acid Weak )、Medium-strong acid Mod ) increased significantly, and the amount of strong acid (Acid Str ) also remain basically unchanged.

[0092] The hydrogen reduction performance of the catalysts obtained in Examples 1-4 and the comparative example was tested by hydrogen temperature programmed reduction test (H2-TPR). The test method was as follows: the sample (50 mg) was heated in a 5% H2 / N2 gas flow (30 ml·min -1 ) at 10℃·min -1 The sample was heated from 100°C to 800°C at a heating rate of . The hydrogen reduction performance of the obtained catalyst is as follows Figure 4 As shown:

[0093] from Figure 4 It can be seen that in Example 1 of the present invention, the reduction peak of Ru / Co3O4@CeO2-MOF shifts to 72°C, which is lower than Example 4 (78°C), Example 3 (80°C), Example 2 (81°C), and the comparative example (275°C).

[0094] The oxygen species distribution of the catalysts obtained in Examples 1-4 and the comparative example was tested by oxygen temperature programmed desorption test (O2-TPD). O2-TPD was carried out in a U-shaped quartz tube, and the oxygen desorption signal was recorded by a chemical adsorption analyzer TP-5080. The reactor was heated at 10°C·min -1 The oxygen species distribution of the obtained catalyst is as follows: Figure 5 As shown:

[0095] from Figure 5 It can be seen that in Example 1 of the present invention, Ru / Co3O4@CeO2-MOF has the highest O S-A The total amount is higher than that of Examples 2, 3 and 4, and is significantly better than that of the comparative example.

[0096] Catalytic performance test: Examples 1-4 and comparative examples were tested for the catalytic effect of the simultaneous removal of toluene and chlorobenzene combustion reaction. The test method is as follows. 400 mg of catalyst was loaded into a quartz fixed bed microreactor. The evaluation parameters were as follows: flow rate was 100 ml·min -1 , the initial concentration of toluene gas was 1000 ppm, the initial concentration of chlorobenzene gas was 250 ppm, the balance gas was 80% N2 + 20% O2, and the concentration of the tail gas was measured by GC (GC-9790, Fuli) gas chromatograph, the space velocity was 15000 mL g -1 ·h -1 , the reaction pressure is 0.1M Pa.

[0097] In this embodiment, the conversion rate = ((toluene / chlorobenzene) initial concentration - (toluene / chlorobenzene) concentration in tail gas) / (toluene / chlorobenzene) initial concentration × 100%. The test results are as follows Figure 6As shown in Table 1-2.

[0098] Table 1: Catalytic effect data of simultaneous catalytic combustion of toluene prepared by catalysts of Examples 1-4 and Comparative Examples

[0099] Temperature℃Toluene conversion% 200 220 240 260 280 300 Example 1 15.8 93.0 99.1 99.6 99.7 99.9 Example 2 16.1 42.0 81.1 97.1 97.8 99.5 Example 3 14.1 78.6 96.4 97.2 98.0 99.4 Example 4 9.2 59.0 97.4 97.9 99.4 99.5 Comparative Example 84.6 87.7 89.0 86 84.8 88.9

[0100] Table 2: Catalytic effect data of simultaneous catalytic combustion of chlorobenzene prepared by the catalysts of Examples 1-4 and Comparative Examples

[0101] Temperature℃Chlorobenzene conversion% 200 220 240 260 280 300 Example 1 6.4 71.2 86.0 96.0 96.0 97.6 Example 2 1.6 9.2 38.8 70.0 78.0 84.8 Example 3 1.6 21.2 65.6 81.6 85.0 87.6 Example 4 1.6 10.8 63.2 88.8 96.0 96.8 Comparative Example 62.4 64.4 67.6 60.4 46.4 41.2

[0102] As can be seen from Table 1-2, the core-shell Ru / Co3O4@CeO2-MOF catalyst prepared in Example 1 exhibits the best catalytic activity when catalyzing the combustion of toluene and chlorobenzene at the same time, and the catalytic activity is from high to low: Example 1> Example 4> Example 3> Example 2> Comparative Example. Specifically, at 260°C, the conversion rates of toluene and chlorobenzene in Example 1 are 99.6% and 96.0%, respectively, which are improved compared with Examples 2, 3 and 4. And at 280-300°C, the conversion rate of toluene in Example 1 under mixed conditions is about 10% higher than that of the comparative example, while the conversion rate of chlorobenzene is nearly doubled compared with the comparative example.

[0103] from Figure 6 It is also observed that compared with the comparative example, Example 1 has excellent stability and catalytic activity. Under the long-term stability test at 280°C, the catalytic performance of toluene and chlorobenzene remains almost unchanged, with excellent stability and durability. This shows that the ordered configuration of Co3O4 as the core, CeO2-MOF as the sub-outer layer and the outermost layer Ru plays a key role in improving the simultaneous catalytic combustion performance of toluene and chlorobenzene. It shows that the core-shell Ru / Co3O4@CeO2-MOF obtained by the layered orderly construction preparation method has better performance in the simultaneous catalytic combustion of multi-component chlorine-containing VOCs.

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application and not to limit it. Although the present application has been described in detail with reference to the preferred embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present application can still be modified or some technical features can be replaced by equivalents, which should all be included in the scope of the technical solution requested for protection in this application.

Claims

1. The use of the catalyst in the catalytic combustion of chlorine-containing multi-component VOCs reaction, characterized in that: The catalyst comprises the following components in weight percentage: Co3O42.5%~5%; CeO2-MOF 93%~97%; Ru0.5%~2%; The preparation of the catalyst Ru / Co3O4@CeO2-MOF comprises the following steps: adding Co3O4 to water, then adding CeO2-MOF thereto, stirring evenly, dropping RuCl3 solution in a water bath at 70°C to 80°C, continuing stirring for 3h to 5h to volatilize H2O, drying the obtained solid at 80°C to 120°C for 8h to 24h, and then calcining at 300°C to 500°C for 1h to 6h to obtain the obtained solid; The CeO2-MOF is prepared by in-situ pyrolysis of Ce-MOF, and the specific method is: heating a mixed solution containing 1,3,5-benzenetricarboxylic acid, H2O and ethanol to 50°C to 70°C, adding Ce(NO3)3·6H2O aqueous solution to the mixed solution obtained above under vigorous stirring, continuing to vigorously stir for 0.5h to 1.5h, filtering and collecting the precipitate, washing it with ethanol and deionized water for several times, reacting it at 80°C to 110°C for 8h to 24h, and calcining it at 300°C to 500°C for 1h to 4h to obtain; The Co3O4 is prepared by a hydrothermal method, and the specific method is: dissolving (CH3CO2)2Co in water, adding urea under stirring, the mass ratio of (CH3CO2)2Co, water and urea is 1.25:10-40:0.3, stirring vigorously for 1.5h-2.5h after the addition, transferring to a hydrothermal kettle, reacting at 90°C-110°C for 10h-14h, filtering and washing to neutrality, and then drying the obtained precipitate at 100°C-110°C for 10h-14h to obtain; The catalytic reaction conditions of the catalyst are: the concentration of toluene is 800ppm-1200ppm, the concentration of chlorobenzene is 100ppm-400pm, and the reaction space velocity is 10000mL·g -1 ·h -1 ~20000mL·g -1 ·h -1 .

2. The use of the catalyst in the catalytic combustion of chlorine-containing multi-component VOCs reaction, characterized in that: The catalyst Ru-Co / CeO2-MOF includes CeO2-MOF as a core, and Co3O4 and Ru supported on the CeO2-MOF, including the following components in weight percentage: The catalyst Ru-Co / CeO2-MOF includes the following components in weight percentage: Co3O43.2%~4.5%; CeO2-MOF 94%~96%; Ru0.8%~1.5%; The preparation method of the catalyst Ru-Co / CeO2-MOF is prepared by a hydrothermal method, and the specific method is as follows: Add (CH3CO2)2Co·4H2O to H2O, drop RuCl3 solution into it while stirring, stir evenly, immerse CeO2-MOF in the above solution, continue stirring for 3h~5h, transfer to an autoclave, react for 10h~14h at 95℃~105℃, take out after natural cooling, continue stirring for 3h~5h in a 70℃~80℃ water bath, continue stirring to volatilize H2O, dry the obtained solid at 100℃~120℃ for 10h~14h, and calcine at 350℃~450℃ for 3h~5h to obtain; The CeO2-MOF is prepared by in-situ pyrolysis of Ce-MOF, and the specific method is as follows: Heat a mixed solution containing 1,3,5-benzenetricarboxylic acid, H2O and ethanol to 50°C to 70°C, add Ce(NO3)3·6H2O aqueous solution to the mixed solution under vigorous stirring, continue to stir vigorously for 0.5h to 1.5h, collect the precipitate by filtration, wash it with ethanol and deionized water several times, react it at 95°C to 105°C for 10h to 14h, and calcine it at 350°C to 450°C for 0.5h to 2h to obtain; The catalytic reaction conditions of the catalyst are: the concentration of toluene is 800ppm-1200ppm, the concentration of chlorobenzene is 100ppm-400pm, and the reaction space velocity is 10000mL·g -1 ·h -1 ~20000mL·g -1 ·h -1 .

3. The use according to claim 2, characterized in that: The specific method is: Add (CH3CO2)2Co·4H2O to H2O, drop RuCl3 solution into it while stirring, and after stirring evenly, immerse CeO2-MOF in the above solution, continue stirring in a water bath at 70℃~80℃ for 3h~5h, then continue stirring to volatilize H2O, dry the obtained solid at 100℃~120℃ for 10h~14h, and calcine at 350℃~450℃ for 3h~5h.

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