A CoMn solid solution composite oxide catalyst, preparation method and application

Abstract

The present invention discloses a CoMn solid solution composite oxide catalyst, a preparation method and its application in catalytic oxidation of toluene. The catalyst is a Co-O-Mn solid solution formed by dissolving Co species into a MnO2 lattice, and the mass fraction of Co3O4 in the catalyst is 0.5-10wt%. The preparation method comprises: dissolving manganese nitrate and cobalt nitrate in deionized water to obtain liquid A; dissolving ammonium carbonate in deionized water and ultrasonically treating to obtain liquid B; dripping liquid B into liquid A drop by drop under stirring to obtain a mixed solution; heating the mixed solution in a water bath and stirring to obtain a precipitate; centrifuging and drying the precipitate, and calcining in an air atmosphere to obtain a CoMn solid solution composite oxide catalyst. The catalyst preparation step of the present invention is simple, the conditions are mild, and it has good low-temperature toluene catalytic oxidation activity, good catalytic stability and water resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental catalytic purification, relates to a catalyst, specifically to a CoMn solid solution composite oxide catalyst, and particularly to a preparation method of the CoMn solid solution composite oxide catalyst and application thereof in catalytic oxidation of toluene. Background Art

[0002] Volatile organic compounds (VOCs) have become one of the main air pollutants. Toluene is the core representative pollutant of VOCs and an important factor affecting air quality. It mainly comes from the petrochemical industry, pharmaceutical industry, decoration coating industry and transportation activities. It has the characteristics of wide emission sources, large emission volume and strong secondary pollution. Human contact with toluene can cause health-related problems such as liver and brain damage, respiratory irritation, damage to the reproductive system and nervous system, and even induce cancer. Therefore, developing effective technologies to reduce or even eliminate toluene emissions has become an important research field.

[0003] To date, various technologies have been developed to remove toluene, such as adsorption, biodegradation, catalytic oxidation / combustion, plasma catalysis, and photocatalysis. Among these technologies, catalytic oxidation technology is considered to be a very promising technology due to its lack of secondary harmful pollutants, energy saving, environmental protection, and low operating cost. Catalysts are the core of catalytic oxidation technology. However, this technology still lacks stable and reliable catalysts in industrial applications. Therefore, it is of great significance to construct catalysts with excellent activity, good durability, and low cost and high efficiency for catalytic oxidation of toluene.

[0004] Among various transition metal oxides, manganese oxides (Mn2O3, Mn3O4 and MnO2) show excellent catalytic oxidation performance due to the advantages of variable valence state of Mn element, large adjustable space of crystal phase structure, high oxygen species mobility and good oxygen storage capacity. Co is also one of the transition metals with variable valence state. Since the Co-O bond energy of cobalt oxide is weak and easy to break, and it has high oxygen mobility, it is often used as a catalytic oxidation catalyst. Compared with single-component Mn oxide or Co oxide, Co-Mn composite oxide catalysts (such as CoMn2O4, MnCo2O4 spinel) formed by the introduction of Co into Mn oxide or Mn into Co oxide have better oxygen storage / release capacity and oxygen species mobility, and have good catalytic performance for the catalytic oxidation of toluene. However, in existing reports, CoMn composite oxides are mainly CoMn2O4 or / and MnCo2O4 spinel, and the oxygen species in the spinel composite oxides mainly exist in the form of lattice oxygen. It is difficult for lattice oxygen species to migrate and release in the spinel composite oxide, which is not conducive to the formation of active oxygen species and oxygen vacancies. Summary of the invention

[0005] In view of the defects of the prior art, the purpose of the present invention is to provide a CoMn solid solution oxide catalyst for catalytic oxidation of toluene and a preparation method thereof. The catalyst has the characteristics of high activity, good stability and good water resistance, and the preparation method is simple, and efficient conversion of toluene can be achieved at a relatively low temperature.

[0006] To achieve the above object, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a CoMn solid solution composite oxide catalyst, wherein the catalyst is a Co-O-Mn solid solution formed by dissolving Co species into a MnO2 lattice, and the mass fraction of Co3O4 in the catalyst is 0.5 to 10 wt%.

[0008] In a second aspect, the present invention provides a method for preparing a CoMn solid solution composite oxide catalyst, comprising:

[0009] Dissolve manganese nitrate and cobalt nitrate in deionized water to obtain solution A;

[0010] Dissolve ammonium carbonate in deionized water and perform ultrasonic treatment to obtain solution B;

[0011] Add liquid B dropwise into liquid A under stirring to obtain a mixed solution;

[0012] The mixed solution is heated in a water bath with stirring to obtain a precipitate;

[0013] The precipitate was centrifugally dried and calcined in an air atmosphere to obtain a CoMn solid solution composite oxide catalyst.

[0014] Furthermore, the mass ratio of cobalt nitrate to manganese nitrate is 0.05-2.00:3.1-4.6.

[0015] Furthermore, the mass ratio of ammonium carbonate to the sum of manganese nitrate and cobalt nitrate is 3.00-5.00:3.15-6.6.

[0016] Further, the ammonium carbonate is dissolved in deionized water and the ultrasonic treatment time is 15 to 45 minutes.

[0017] Further, the mixed solution is stirred in a water bath at 50-70° C. for 4.0-6.0 h.

[0018] Furthermore, the precipitate is centrifuged and then dried at 60-80° C. for 6.0-12.0 h, and calcined at 300-500° C. in an air atmosphere for 2.0-4.0 h.

[0019] In a third aspect, the present invention provides use of the CoMn solid solution composite oxide catalyst described in the first aspect in catalytic oxidation of toluene.

[0020] Furthermore, in the application of the CoMn solid solution composite oxide catalyst in the catalytic oxidation of toluene, the reaction temperature of the catalytic oxidation of toluene is 130-200°C.

[0021] Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects:

[0022] (1) The CoMn solid solution composite oxide catalyst of the present invention has a controllable structure, good redox performance and high oxygen mobility, and exhibits good low-temperature catalytic oxidation activity for toluene;

[0023] (2) In the CoMn solid solution composite oxide catalyst of the present invention, Co species dissolve in the MnO2 lattice to form a Co-O-Mn solid solution structure. The interaction between Co and Mn oxides weakens the metal-O bond in the catalyst and promotes the generation of oxygen vacancies and the formation of active oxygen species on the catalyst surface, which is beneficial to the adsorption and activation of toluene and O2 molecules, thereby improving the catalytic oxidation performance of the CoMn solid solution composite oxide catalyst.

[0024] (3) The CoMn solid solution composite oxide catalyst of the present invention has good catalytic oxidation activity for toluene at a concentration of 10,000 ppm at a reaction temperature of 130 to 200°C. Among them, the Co1Mn solid solution composite oxide catalyst has the best toluene catalytic oxidation activity. At a reaction temperature of 150°C, the toluene oxidation removal rate exceeds 97.0%; at a reaction temperature of 170°C, the toluene removal rate exceeds 99.0%;

[0025] (4) The CoMn solid solution composite oxide catalyst of the present invention exhibits good catalytic stability and water resistance and is not easily deactivated;

[0026] (5) The present invention adopts a precipitation method to prepare the CoMn solid solution composite oxide catalyst. The preparation method is simple, the preparation conditions are mild, and it can be prepared on a large scale. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0028] Figure 1 The MnO2 oxide catalyst, Co3O4 oxide catalyst, Co 0.5 Mn, Co 0.8Mn, Co1Mn, Co5Mn and Co 10 XRD pattern of Mn solid solution composite oxide catalyst;

[0029] Figure 2 The MnO2 oxide catalyst, Co3O4 oxide catalyst, Co 0.5 Mn, Co 0.8 Mn, Co1Mn, Co5Mn and Co 10 Raman diagram of Mn solid solution composite oxide catalyst;

[0030] Figure 3 The MnO2 oxide catalyst, Co3O4 oxide catalyst, Co 0.5 Mn, Co 0.8 Mn, Co1Mn, Co5Mn and Co 10 O2-TPD diagram of Mn solid solution composite oxide catalyst;

[0031] Figure 4 The MnO2 oxide catalyst, Co3O4 oxide catalyst, Co 0.5 Mn, Co 0.8 Mn, Co1Mn, Co5Mn and Co 10 H2-TPR diagram of Mn solid solution composite oxide catalyst;

[0032] Figure 5 The MnO2 oxide catalyst, Co3O4 oxide catalyst, Co 0.5 Mn, Co 0.8 Mn, Co1Mn, Co5Mn and Co 10 Performance diagram of toluene catalytic oxidation over Mn solid solution composite oxide catalyst;

[0033] Figure 6 Co prepared in Examples 3 to 7 of the present invention 0.5 Mn, Co 0.8 Mn, Co1Mn, Co5Mn and Co 10 Catalytic stability performance diagram of Mn solid solution composite oxide catalyst.

[0034] Figure 7 Co prepared in Examples 3 to 7 of the present invention 0.5 Mn, Co 0.8 Mn, Co1Mn, Co5Mn and Co 10 Water resistance diagram of Mn solid solution composite oxide catalyst. DETAILED DESCRIPTION

[0035] The present invention will be further described below in conjunction with specific examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention.

[0036] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in this application should have the common meanings understood by those skilled in the art to which the invention belongs.

[0037] Unless otherwise specified, the raw materials in the examples of the present invention were purchased from commercial sources.

[0038] Example 1 Preparation of MnO2 oxide catalyst

[0039] Take 5.35mL of 50wt% Mn(NO3)2 solution and dissolve it in 35mL deionized water; dissolve 4.4160g of (NH4)2CO3 in 30mL deionized water, ultrasonically treat for 30min, then drip the (NH4)2CO3 solution drop by drop into the above Mn(NO3)2 solution, and then stir the mixed solution in a water bath at 60℃ for 6.0h. The obtained precipitate was centrifuged and dried at 70℃ for 12.0h, and then calcined in an air atmosphere at 400℃ for 3.0h to obtain a MnO2 oxide catalyst.

[0040] Air was introduced into the 0°C constant temperature bubbling device, and air with a toluene concentration of 10,000 ppm was continuously produced. 50 mg of MnO2 oxide catalyst was filled in the fixed bed reactor at a space velocity of 60,000 mL·g -1 ·h -1 Under the condition of , the catalyst was heated to the set temperature at a heating rate of 10℃ / min, and the toluene oxidation performance was tested within the set temperature range (160-260℃). The toluene content in the tail gas before and after the reaction was detected online using a gas chromatograph equipped with an FID detector. The toluene conversion rate was calculated by the following formula:

[0041]

[0042] Figure 1 The XRD pattern of the MnO2 oxide catalyst prepared in this example is shown. It can be seen from the figure that the MnO2 oxide catalyst has a θ Obvious XRD diffraction peaks were formed at =37.6, 40.8, 42.8, 56.4, 66.9 and 79.3°, which were attributed to the MnO2 crystal phase with a hexagonal crystal structure, indicating the formation of single-component MnO2.

[0043] Figure 2The Raman graph of the MnO2 oxide catalyst prepared in this example is shown. It can be seen from the figure that the MnO2 oxide is observed at 633 cm -1 A Raman peak is formed at , which corresponds to the symmetric stretching vibration of the Mn-O bond perpendicular to the direction of the [MnO6] octahedral double chain, further explaining the formation of MnO2.

[0044] Figure 3 The O2-TPD diagram of the MnO2 oxide catalyst prepared in this embodiment is shown. It can be seen from the figure that the MnO2 oxide catalyst has the lowest oxygen desorption peak temperature and a larger oxygen desorption amount, which indicates that the MnO2 oxide catalyst has good oxygen desorption performance and lattice oxygen migration ability.

[0045] Figure 4 The H2-TPR diagram of the MnO2 oxide catalyst prepared in this embodiment is shown. It can be seen from the diagram that the hydrogen consumption peak temperature of the MnO2 oxide catalyst is low but the hydrogen consumption is minimal, indicating that the MnO2 oxide catalyst has good reducibility but a small number of reducible species.

[0046] Figure 5 The toluene oxidation activity diagram of the MnO2 oxide catalyst prepared in this example is shown. It can be seen from the figure that the toluene conversion rate of the MnO2 oxide catalyst at 210°C exceeds 98.0%.

[0047] Example 2 Preparation of Co3O4 Oxide Catalyst

[0048] 1.3386g of Co(NO3)2·6H2O was dissolved in 35mL of deionized water; 0.4416g of (NH4)2CO3 was dissolved in 30mL of deionized water and ultrasonically treated for 30min; then the (NH4)2CO3 solution was dripped into the above Co(NO3)2·6H2O solution drop by drop, and the mixed solution was stirred in a water bath at 60℃ for 6.0h. The obtained precipitate was centrifuged and dried at 70℃ for 12.0h, and calcined at 400℃ in air atmosphere for 3.0h to obtain Co3O4 oxide catalyst.

[0049] Air was introduced into the 0°C constant temperature bubbling device, and air with a toluene concentration of 10,000 ppm was continuously generated. 50 mg of Co3O4 oxide catalyst was filled in the fixed bed reactor at a space velocity of 60,000 mL·g -1 ·h -1 Under the conditions of , the catalyst was heated to the set temperature at a heating rate of 10℃ / min, and the toluene oxidation performance was tested within the set temperature range (200-260℃). The toluene content in the tail gas before and after the reaction was detected online using a gas chromatograph equipped with an FID detector.

[0050] Figure 1 The XRD pattern of the Co3O4 oxide catalyst prepared in this example is shown. It can be seen from the figure that the Co3O4 oxide catalyst has θ Obvious XRD diffraction peaks are formed at =31.2, 36.9, 38.5, 44.9, 55.7, 59.4, 65.3, 77.3 and 78.4°, which are attributed to the Co3O4 crystal phase with spinel structure, indicating the formation of single-component Co3O4.

[0051] Figure 2 The Raman graph of the Co3O4 oxide catalyst prepared in this example is shown. It can be seen from the figure that the Co3O4 oxide is observed in the range of 100-1000 cm -1 Five obvious Raman peaks were formed in the range, located at 193, 471, 514, 615 and 683 cm -1 The formation of Co3O4 is further explained.

[0052] Figure 3 The O2-TPD diagram of the Co3O4 oxide catalyst prepared in this example is shown. It can be seen from the figure that the Co3O4 oxide catalyst has the highest oxygen desorption peak temperature and the smallest oxygen desorption amount, indicating that the oxygen desorption performance and lattice oxygen migration ability of the Co3O4 oxide catalyst are poor.

[0053] Figure 4 The H2-TPR diagram of the Co3O4 oxide catalyst prepared in this example is shown. It can be seen from the figure that the Co3O4 oxide catalyst forms two hydrogen consumption peaks at 340°C and 390°C, which are respectively attributed to the continuous reduction process of Co3O4→CoO→Co.

[0054] Figure 5 The toluene oxidation activity diagram of the Co3O4 oxide catalyst prepared in this example is shown. It can be seen from the figure that the toluene conversion rate of the Co3O4 oxide catalyst at 230°C exceeds 99.0%.

[0055] Example 3 Preparation of Co 0.5 Mn solid solution composite oxide catalyst

[0056] (1) 5.35 mL of 50 wt% Mn(NO3)2 solution and 0.0742 g of Co(NO3)2·6H2O were dissolved in 35 mL of deionized water so that the mass fraction of Co3O4 in the obtained catalyst was 0.5 wt%. The obtained solution was marked as solution A.

[0057] (2) Dissolve 4.4405 g (NH4)2CO3 in 30 mL deionized water, ultrasonicate for 30 min, and label the resulting solution as solution B;

[0058] (3) Add liquid B dropwise into liquid A under stirring to obtain a mixed solution;

[0059] (4) stirring the mixed solution in a water bath at 60° C. for 6.0 h to obtain a precipitate;

[0060] (5) The obtained precipitate was centrifuged and dried at 70°C for 12.0 h, and then calcined in air at 400°C for 3.0 h to obtain Co 0.5 Mn solid solution composite oxide catalyst.

[0061] Air was introduced into the 0°C constant temperature bubbling device, and air with a toluene concentration of 10,000 ppm was continuously generated. 50 mg of Co 0.5 Mn solid solution composite oxide catalyst, at a space velocity of 60,000 mL g -1 ·h -1 Under the conditions of , the catalyst was heated to the set temperature at a heating rate of 10℃ / min, and the toluene oxidation performance was tested within the set temperature range (120-260℃). The toluene content in the tail gas before and after the reaction was detected online using a gas chromatograph equipped with an FID detector.

[0062] Example 4 Preparation of Co 0.8 Mn solid solution composite oxide catalyst

[0063] The difference between Example 4 and Example 3 is that: (1) 5.35 mL of 50 wt% Mn(NO3)2 solution and 0.1187 g of Co(NO3)2·6H2O were dissolved in 35 mL of deionized water, so that the mass fraction of Co3O4 in the obtained catalyst was 0.8 wt%; (2) 4.4552 g of (NH4)2CO3 was dissolved in 30 mL of deionized water, and ultrasonic treatment was performed for 30 min. The obtained solution was marked as solution B; the other steps were the same as those in Example 3, and the prepared catalyst was marked as Co 0.8 Mn solid solution composite oxide catalyst.

[0064] Air was introduced into the 0°C constant temperature bubbling device, and air with a toluene concentration of 10,000 ppm was continuously generated. 50 mg of Co 0.8 Mn solid solution composite oxide catalyst, at a space velocity of 60,000 mL g -1 ·h -1 Under the conditions of , the catalyst was heated to the set temperature at a heating rate of 10℃ / min, and the toluene oxidation performance was tested within the set temperature range (120-260℃). The toluene content in the tail gas before and after the reaction was detected online using a gas chromatograph equipped with an FID detector.

[0065] Example 5 Preparation of Co1Mn solid solution composite oxide catalyst

[0066] The difference between Example 5 and Example 3 is that: (1) 5.35 mL of 50 wt% Mn(NO3)2 solution and 0.1484 g of Co(NO3)2·6H2O were dissolved in 35 mL of deionized water, so that the mass fraction of Co3O4 in the obtained catalyst was 1 wt%; (2) 4.4650 g of (NH4)2CO3 was dissolved in 30 mL of deionized water and ultrasonically treated for 30 min. The other steps were the same as those in Example 3, and the prepared catalyst was recorded as Co1Mn solid solution composite oxide catalyst.

[0067] Air was introduced into the 0°C constant temperature bubbling device, and air with a toluene concentration of 10,000 ppm was continuously generated. 50 mg of Co1Mn solid solution composite oxide catalyst was filled in the fixed bed reactor at a space velocity of 60,000 mL·g -1 ·h -1 Under the conditions of , the catalyst was heated to the set temperature at a heating rate of 10℃ / min, and the toluene oxidation performance was tested within the set temperature range (120-260℃). The toluene content in the tail gas before and after the reaction was detected online using a gas chromatograph equipped with an FID detector.

[0068] Example 6 Preparation of Co5Mn solid solution composite oxide catalyst

[0069] The difference between Example 6 and Example 3 is that: (1) 5.35 mL of 50 wt% Mn(NO3)2 solution and 0.7420 g of Co(NO3)2·6H2O are dissolved in 35 mL of deionized water so that the mass fraction of Co3O4 in the obtained catalyst is 5 wt%; (2) 4.6610 g of (NH4)2CO3 is dissolved in 30 mL of deionized water and ultrasonically treated for 30 min; the other steps are the same as in Example 3, and the prepared catalyst is recorded as Co5Mn solid solution composite oxide catalyst.

[0070] Air was introduced into the 0°C constant temperature bubbling device, and air with a toluene concentration of 10,000 ppm was continuously generated. 50 mg of Co5Mn solid solution composite oxide catalyst was filled in the fixed bed reactor at a space velocity of 60,000 mL·g -1 ·h -1 Under the conditions of , the catalyst was heated to the set temperature at a heating rate of 10℃ / min, and the toluene oxidation performance was tested within the set temperature range (120-260℃). The toluene content in the tail gas before and after the reaction was detected online using a gas chromatograph equipped with an FID detector.

[0071] Example 7 Preparation of Co 10 Mn solid solution composite oxide catalyst

[0072] The difference between Example 7 and Example 3 is that: (1) 5.35 mL of 50 wt% Mn(NO3)2 solution and 1.4840 g of Co(NO3)2·6H2O were dissolved in 35 mL of deionized water, so that the mass fraction of Co3O4 in the obtained catalyst was 10%; (2) 4.9060 g of (NH4)2CO3 was dissolved in 30 mL of deionized water and ultrasonically treated for 30 min. The other steps were the same as those in Example 3, and the prepared catalyst was recorded as Co 10 Mn solid solution composite oxide catalyst.

[0073] Air was introduced into the 0°C constant temperature bubbling device, and air with a toluene concentration of 10,000 ppm was continuously generated. 50 mg of Co 10 Mn solid solution composite oxide catalyst, at a space velocity of 60,000 mL g -1 ·h -1 Under the conditions of , the catalyst was heated to the set temperature at a heating rate of 10℃ / min, and the toluene oxidation performance was tested within the set temperature range (120-260℃). The toluene content in the tail gas before and after the reaction was detected online using a gas chromatograph equipped with an FID detector.

[0074] Figure 1 The MnO2 oxide catalyst, Co3O4 oxide catalyst, Co 0.5 Mn, Co 0.8 Mn, Co1Mn, Co5Mn and Co 10 XRD pattern of Mn solid solution composite oxide catalyst. It can be seen from the figure that Co 0.5 Mn, Co 0.8 Mn, Co1Mn, Co5Mn and Co 10 Only MnO2 phase was observed in the Mn solid solution composite oxide, and the XRD peak of Co3O4 phase was not detected, and the XRD peak shifted toward the low angle direction, confirming the formation of Co-O-Mn solid solution structure.

[0075] Figure 2 The MnO2 oxide catalyst, Co3O4 oxide catalyst, Co 0.5 Mn, Co 0.8 Mn, Co1Mn, Co5Mn and Co 10 Raman diagram of Mn solid solution composite oxide catalyst. It can be seen from the figure that Co 0.5 Mn, Co 0.8Mn, Co1Mn, Co5Mn and Co 10 Only the symmetric stretching vibration peak of Mn-O bond in MnO2 phase was observed in Mn solid solution composite oxide, which further illustrates the formation of Co-O-Mn solid solution.

[0076] Figure 3 The MnO2 oxide catalyst, Co3O4 oxide catalyst, Co 0.5 Mn, Co 0.8 Mn, Co1Mn, Co5Mn and Co 10 O2-TPD diagram of Mn solid solution composite oxide catalyst. It can be seen from the figure that the Co1Mn catalyst has the lowest oxygen desorption peak temperature in the β and γ peak regions and the largest oxygen desorption amount in the α peak region, indicating that the Co1Mn solid solution composite oxide catalyst has good oxygen desorption performance and lattice oxygen migration ability.

[0077] Figure 4 The MnO2 oxide catalyst, Co3O4 oxide catalyst, Co 0.5 Mn, Co 0.8 Mn, Co1Mn, Co5Mn and Co 10 H2-TPR diagram of Mn solid solution composite oxide catalyst. It can be seen from the figure that Co 0.5 Mn, Co 0.8 Mn, Co1Mn, Co5Mn and Co 10 The Mn solid solution composite oxide catalyst has a larger hydrogen consumption, indicating that the CoMn solid solution composite oxide catalyst has a larger amount of reducible species on its surface.

[0078] Figure 5 The MnO2 oxide catalyst, Co3O4 oxide catalyst, Co 0.5 Mn, Co 0.8 Mn, Co1Mn, Co5Mn and Co 10 Toluene oxidation activity diagram of Mn solid solution composite oxide catalyst. It can be seen from the figure that Co 0.5 Mn, Co 0.8 Mn, Co1Mn, Co5Mn and Co 10 The catalytic oxidation activity of toluene over the Mn solid solution composite oxide catalysts is better than that over the single component MnO2 and CuO catalysts. When the reaction temperature is 150°C, the toluene oxidation removal rate of the Co1Mn solid solution composite oxide catalyst exceeds 97.0%. When the reaction temperature is 170°C, the toluene oxidation removal rate of the Co1Mn solid solution composite oxide catalyst exceeds 99.0%. When the reaction temperature is 190°C, the toluene oxidation removal rate of the Co1Mn solid solution composite oxide catalyst exceeds 99.0%. 0.5The toluene oxidation removal rate of Mn solid solution composite oxide catalyst exceeded 97.0%; when the reaction temperature was 170℃, Co 0.8 The toluene oxidation removal rate of the Mn solid solution composite oxide catalyst exceeded 99.0%; when the reaction temperature was 180°C, the toluene oxidation removal rate of the Co5Mn solid solution composite oxide catalyst exceeded 96.0%; when the reaction temperature was 200°C, the toluene oxidation removal rate of the Co5Mn solid solution composite oxide catalyst exceeded 99.0%; when the reaction temperature was 210°C, the 10 The toluene oxidation removal rate of the Mn solid solution composite oxide catalyst exceeded 97.0%. Among them, the Co1Mn solid solution composite oxide catalyst had the best toluene oxidation activity.

[0079] Figure 6 Co prepared in Examples 3 to 7 of the present invention 0.5 Mn, Co 0.8 Mn, Co1Mn, Co5Mn and Co 10 Catalytic stability performance diagram of Mn solid solution composite oxide catalyst. It can be seen from the figure that in the 900min continuous test, Co 0.5 Mn, Co 0.8 Mn, Co1Mn, Co5Mn and Co 10 The toluene conversion of the Mn solid solution composite oxide catalyst remained at a high level (>95.0%), and no obvious activity loss was observed.

[0080] Figure 7 Co prepared in Examples 3 to 7 of the present invention 0.5 Mn, Co 0.8 Mn, Co1Mn, Co5Mn and Co 10 Water resistance performance diagram of Mn solid solution composite oxide catalyst. It can be seen from the figure that when there is no water vapor in the raw gas, the toluene conversion rate always remains at a high level. When 5 vol% water vapor is introduced, the toluene conversion rate decreases slightly; after the water vapor supply is stopped, the toluene conversion rate returns to the level in the anhydrous atmosphere. The above results show that Co 0.5 Mn, Co 0.8 Mn, Co1Mn, Co5Mn and Co 10 Mn solid solution composite oxide catalyst has good water resistance.

[0081] The present invention has been disclosed above with preferred embodiments, but they are not intended to limit the present invention. Any technical solutions obtained by adopting equivalent replacement or equivalent transformation solutions fall within the protection scope of the present invention.

Claims

1. Application of a CoMn solid solution composite oxide catalyst in catalytic oxidation of toluene, characterized in that: The catalyst is a Co-O-Mn solid solution formed by dissolving Co species into the MnO2 lattice; the temperature of the toluene catalytic oxidation reaction is 130-200° C. The CoMn solid solution composite oxide catalyst is prepared according to the following method: Dissolve manganese nitrate and cobalt nitrate in deionized water to obtain solution A; Dissolve ammonium carbonate in deionized water and perform ultrasonic treatment to obtain solution B; Add liquid B dropwise into liquid A under stirring to obtain a mixed solution; The mixed solution is heated in a water bath with stirring to obtain a precipitate; The precipitate is centrifugally dried and calcined in an air atmosphere to obtain a CoMn solid solution composite oxide catalyst; The mass ratio of cobalt nitrate to manganese nitrate is 0.05-2.00:3.1-4.6; the mass ratio of ammonium carbonate to the sum of manganese nitrate and cobalt nitrate is 3.00-5.00:3.15-6.6; the precipitate is centrifuged and then dried at 60-80° C. for 6.0-12.0 h, and calcined in an air atmosphere at 300-400° C. for 2.0-4.0 h.

2. The use according to claim 1, characterized in that: The ultrasonic treatment time is 15 to 45 minutes.

3. The use according to claim 1, characterized in that: The mixed solution was stirred in a water bath at 50-70°C for 4.0-6.0 h.

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