WO2017187400A1

WO2017187400A1 - Supported cobaltosic oxide catalyst, and preparation method and use therefor

Info

Publication number: WO2017187400A1
Application number: PCT/IB2017/052468
Authority: WO
Inventors: 孙予罕; 祝艳; 杨娜婷; 孙永南; 张军
Original assignee: 能源技术研究所
Priority date: 2016-04-28
Filing date: 2017-04-28
Publication date: 2017-11-02
Also published as: CN105772027A; CN105772027B

Abstract

A supported cobaltosic oxide catalyst, and a preparation method and a use therefor are disclosed in the present invention. The supported cobaltosic oxide catalyst comprises the following components: a noble metal, a noble metal oxide and a cobaltosic oxide, the ratio of the mass of noble metal elements to the total mass of noble metal elements and Co₃O₄ being 1-10:100, and the supported cobaltosic oxide catalyst being a one-dimensional structure. The preparation method being: in a diol system, coprecipitating cobalt salts and an aqueous deposition solution, then adding a noble metal saline solution, and then hydroheating, drying, and calcining to obtain the supported cobaltosic oxide catalyst, coprecipitation and hydrothermal synthesis both being used to prepare said catalyst. The preparation method is easy to carry out, and the catalyst obtained is uniform and stable. When used in a methane catalytic combustion reaction, the catalyst allows potentially for a 100% methane conversion rate when the reaction temperature of CH₄ is 400°C or below. The catalyst demonstrates excellent activity in low temperature oxidation of methane.

Description

Supported tetraoxo-H cobalt catalyst and preparation thereof and application thereof

The invention relates to the field of catalysts, in particular to a supported type of cobalt trioxide catalyst and a preparation method and application thereof. Background technique

Due to the declining world oil reserves, more and more research is now focusing on the development of alternative energy sources, and abundant natural gas energy has become the most promising source of energy in the 21st century. However, as a major component of natural gas, formazan is not only synthesized as a by-product in some industrial synthesis processes, but also a major hydrocarbon air pollutant in natural gas fuel vehicles and natural gas power plants. Its greenhouse effect is C0 ₂ 21 Times. At present, most of the formazan-burning catalysts studied require CH bond cleavage at higher temperatures (>400 °C), which cannot meet the required temperature for natural gas engine exhaust.

The noble metal supported catalyst exhibits good activity for the low temperature combustion reaction of formazan, but the catalyst does not have good stability at high temperatures, and the precious metal is liable to be lost and sintered at a higher temperature, resulting in a decrease in catalyst activity. Carrying precious metals by conventional impregnation methods does not solve these problems well because the method generally lacks the interaction between the noble metal and the support. Co ₃ 0 ₄ because many catalytic reactions has good performance, it is one of the transition metal oxide is the most widely studied of the object, such as methyl embankment oxide, CO oxidation and NO _x reduction reactions. Compared with the conventional supported Pd catalyst, the core-shell catalyst in which Pd is encapsulated in cerium oxide (Pd@Ce0 ₂ ) shows good stability and high catalytic activity. Therefore, the exploration of novel structure of noble metal supported cobalt tetraoxide catalyst has a breakthrough significance for the development of low temperature oxidation of formazan. Summary of the invention

It is an object of the present invention to provide a supported tricobalt catalyst and a preparation method and application thereof. The supported tricobalt catalyst comprises the following components: noble metal, noble metal oxide and tricobalt tetroxide, the ratio of the mass of the noble metal element to the total mass of the noble metal element and Co ₃ 0 ₄ is from 1 to 10:100, the supported tricobalt catalyst It is a one-dimensional structure. The preparation method comprises the following steps: in a glycol system, a cobalt salt is coprecipitated with an aqueous solution of a precipitating agent, and then a precious metal salt solution is added, and the supported cobalt tetraoxide catalyst is obtained by hydrothermal heating, drying and calcination, using a coprecipitation method and hydrothermal reaction. A synthetic method is used to prepare a supported cobalt trioxide catalyst. The preparation method is simple and easy to operate, and the prepared catalyst has uniform morphology and good stability, and can be applied to the catalytic combustion reaction of formazan to make the reaction temperature of CH ₄ below 400 ° C. At the same time, the conversion rate of formazan can be as high as 100%, and has good low temperature oxidation activity of formazan. At the same time, the supported tricobalt catalyst has the advantages of good stability, long service life and good water resistance, and has no obvious deactivation phenomenon after continuous operation for more than 300 hours, and has good industrial application prospect.

The invention is achieved by the following technical solutions:

A first aspect of the present invention provides a supported tricobalt tetroxide catalyst comprising the following components: a noble metal, an oxide of a noble metal, and a tricobalt tetroxide, the ratio of the mass of the noble metal element to the total mass of the noble metal element and Co ₃ 0 ₄ is 1 ~10: 100, the supported tricobalt catalyst is a one-dimensional structure.

The ratio of the mass of the precious metal element to the total mass of the precious metal element and Co ₃ 0 _{4 is} , for example, 1 to 10 _: 100, such as 1 to 1.5 _:

100, 1.5-3: 100, 3-5: 100, 5-6: 100, 6-9: 100 or 9~10: 100. The precious metal and precious metal oxides are nanoparticles with a particle size of <6 nm.

The supported tricobalt catalyst is a nanorod. The one-dimensional structure means that the ratio of length to diameter is greater than one. Preferably, the noble metal element is selected from one or both of Pd, Pt, Au and Ag.

More preferably, when the precious metal elements are two, the mass ratio of the two precious metal elements is 1: 10-10: 1, such as 1 :

10-1: 5, 1: 5-1: 3, 1: 3-1: 1, 1: 1-3: 1, 3: 1-5: 1, 5: 1-10: 1.

The second aspect of the present invention provides a method for preparing the above-mentioned supported tricobalt tetroxide catalyst. According to the composition ratio of the catalyst, in the diol system, the cobalt salt and the precipitant aqueous solution are coprecipitated, and then the precious metal salt solution is added, and the hydrothermal and roasting are obtained. The supported tricobalt catalyst is prepared by a coprecipitation method and a hydrothermal synthesis method to prepare a supported tricobalt catalyst.

The cobalt salt is selected from one or more of cobalt acetate tetrahydrate, cobalt nitrate, cobalt sulfate, and cobalt chloride.

The precipitating agent is selected from one or more of sodium carbonate, ammonium hydrogencarbonate, sodium hydrogencarbonate, and urea.

The glycol is used as a surfactant and a reducing agent in the synthesis, and the glycol is selected from one or more of ethylene glycol, diethylene glycol, propylene glycol and butylene glycol.

Preferably, the preparation method comprises the following steps:

1) co-precipitation: mixing a cobalt salt and a glycol, adding an aqueous solution of a precipitating agent, stirring, adding a precious metal salt solution, and introducing a gas aging;

2) The solution obtained in the step 1) is hydrothermally dried, calcined and calcined to obtain the supported tricobalt catalyst. More preferably, the ratio of the cobalt salt, the precipitant and the glycol is 10 mmol: 10-30 mmol: 20-40 mL, such as the ratio of the cobalt salt to the precipitant is 10 mmol: 10-15 mmol, 10 mmol: 15 -20 mmol, 10 mmol: 20-25 mmol, 10 mmol: 25~30 mmol; the ratio of cobalt salt to glycol is 10 mmol: 20 25 mL, 10 mmol: 25-30 mL Or 10 mmol: 30-40 mL.

A further preferred ratio of cobalt salt, precipitant and glycol is 10 mmol: 20 mmol: 30 mL.

More preferably, the concentration of the aqueous solution of the precipitating agent is 0.1 to 0.3 mol/L, such as 0.1 0.15 mol/L, 0.15 to 0.2 mol/L,

0.2~0.25mol/L or 0.25~0.3mol/L. Still more preferably, the concentration of the aqueous solution of the precipitating agent is 0.2 mol/L.

Preferably, the noble metal salt is a noble metal nitrate or a precious metal chloride. More preferably, the noble metal salt is selected from one or both of palladium nitrate, potassium chloropalladate, platinum nitrate, gold chloride, and silver nitrate.

More preferably, the temperature of the coprecipitation reaction is 60 ~ 120 ° C, such as ^{60 ~ 70 o C, 70 80} ° C or 80 120. C, the reaction time of coprecipitation is 1~3 h, such as l~1.5h, 1.5~2h, 2~2.5h or 2.5~3h. A still more preferred reaction temperature is 80 ° C and the reaction time is 3 h.

More preferably, the precious metal salt solution is added and then introduced into the gas for aging. The gas is nitrogen or argon, enhancing the action of the cobalt salt and the glycol.

More preferably, the hydrothermal conditions are: hydrothermal temperature is 140~200 °C, such as 140~160 °C or 160~200 °C, and the hydrothermal time is 2~4h, such as 2~3h or 3~4h. Further more preferably, the hydrothermal temperature is 160 to 180 ° C, and the hydrothermal time is 3 ho.

More preferably, the drying conditions are: drying temperature is 50 to 80 ° C, such as 50 to 60 ° C or 60 to 80 ° C, and drying time is 8 to 12 hours, such as 8 to 10 hours or 10 to 12 hours. Further more preferably, the drying temperature is 50 to 60 °C.

More preferably, the calcination conditions are: calcination temperature is 250 to 450 ° C, such as 250 to 300 ° C, 300 to 350 ° C, 350 to 400 ° C or 400 to 450 ° C, and the baking time is 1 to 5 hours. Such as 1-2 hours, 2~3 hours, 3~3.5 hours, 3.5~4 hours or 4~5 hours. Further more preferably, the calcination temperature is 300 ° C and the calcination time is 3 to 4 h.

Further more preferably, the calcination heating rate is 1 to 5 ° C / min.

According to a third aspect of the present invention, there is provided the use of the above-mentioned supported tricobalt tetroxide catalyst for the formazan catalytic combustion reaction.

Preferably, the formazan catalytic combustion reaction conditions are: a reaction temperature of 150 to 450 ° C, a reaction pressure of normal pressure; a total flow rate of the reaction of 50 to 100 mL / min, a flow ratio of CH ₄ , 0 ₂ and N ₂ is 1:5~15:84~94, such as CH _{4 and} P 0 ₂ flow rate ratio is 1:5~10 or 1:10-15, CH ₄ and N ₂ flow rate ratio is 1: 84~89 or 1: 89-94; space velocity is 10000~120000 mL/(g.h), such as 10000~20000 mL/(g.h), 20000-3000 mL/(g.h), 30000-4000 mL/(g.h) ), 40000—60000 mL/(g-h) or 60,000~120,000 mL/(g+h). More preferably, the flow ratio of CH ₄ , 0 ₂ and N ₂ is 1:10:89.

The supported tricobalt catalyst of the present invention comprises the following components: noble metal, noble metal oxide and tetraoxide The ratio of the mass of the tricobalt, the noble metal element to the total mass of the noble metal element and Co ₃ 0 ₄ is 1 to 10 _: 100, and the supported tricobalt catalyst is a one-dimensional structure. The preparation method is as follows: in a glycol system, a cobalt salt is coprecipitated with an aqueous solution of a precipitating agent, and then a precious metal salt solution is added, and the supported cobalt trioxide catalyst is obtained by hydrothermal heating and calcination, using a coprecipitation method and a hydrothermal synthesis method. A supported type of cobalt tetraoxide catalyst was prepared in combination. The preparation method is simple and easy to operate, the catalyst prepared uniform morphology, good stability, applied embankment A catalytic combustion reaction CH ₄ can be made at the reaction temperature to 400 ° C, embankment A high conversion rate of 100% , has good hypothermia oxidation activity of onychomycosis. At the same time, the supported tricobalt catalyst has the advantages of good stability, long service life and good water resistance, and has no obvious deactivation phenomenon after continuous operation for more than 300 hours, and has good industrial application prospect. DRAWINGS

Figure la is a TEM image of the catalyst precursor prepared in Example 1.

Figure lb is a TEM image of the catalyst precursor prepared in Example 1 after being calcined.

Figure 2 is an XRD pattern of the catalyst prepared in Example 1.

Fig. 3 is a graph showing the results of the catalyst combustion reaction of the catalyst prepared in Example 1.

Figure 4 is a TEM image of the catalyst precursor prepared in Example 6.

Figure 5 is a TEM image of the catalyst precursor prepared in Example 8.

Fig. 6a and Fig. 6b are TEM images after calcination of the catalyst prepared in Example 12, respectively.

Fig. 7 is a graph showing the results of the catalyst combustion reaction of the catalyst prepared in Example 12. Concrete 3⁄4fc3⁄4r

The technical solutions of the present invention are explained below by specific specific examples. It should be understood that one or more of the method steps referred to in the present invention does not exclude that other method steps exist before or after the combination step or that other method steps can be inserted between the steps explicitly mentioned; it should also be understood that these The examples are only intended to illustrate the invention and are not intended to limit the scope of the invention. Moreover, unless otherwise indicated, the numbering of the method steps is merely a convenient means of identifying the various method steps, and is not intended to limit the order of the various method steps or to limit the scope of the invention, the relative In the case where the technical content is not substantially changed, it is also considered to be an area in which the present invention can be implemented.

The technical details of the present invention are described in detail by the following examples. It is to be noted that the embodiments are merely illustrative of the technical features of the present invention and are not intended to limit the present invention. example 1

3% Pd-Co ₃ 0 ₄ nanorods (3% refers to the ratio of the mass of the precious metal element to the total mass of Co ₃ 0 ₄ , which is the same as defined in the following examples): Weigh 10 mmol of cobalt acetate tetrahydrate (Co (CH _{3 )} COO) ₂ '4H ₂ 0) Dissolved in 30 mL of ethylene glycol, gradually heated to 80 ° C, and then added a 0.2 mol/L Na ₂ CO ₃ aqueous solution dissolved in 100 mL of deionized water. After vigorously stirring for 10 min, 20 mL of a solution of 0.0628 g of Pd(N0 ₃ ) _{2 was added} , and N ₂ aging was continuously introduced thereto. After reacting for one hour, transfer it to an autoclave, heat it at 160 °C for 3 h, cool to room temperature, centrifuge with deionized water, wash it, and dry it under vacuum at 60 °C for 12 h to obtain a catalyst precursor. The TEM image is shown in Figure la and then calcined at 300 °C for 4 h. Finally, the calcined body is ground into a fine powder, extruded in a mold under a pressure of 40 kN, and crushed and sieved to obtain catalyst particles having a particle diameter of 40 to 60. The TEM image is shown in lb, and XRD is shown in Fig. 2. The catalytic reaction conditions are: the temperature of the catalytic reaction is 150~450 °C, the pressure is normal pressure; the total flow rate of the reaction is 50 mL/min, wherein the flow rates of the three gases are CH ₄ :0 ₂ :N ₂ =1 : 10:89; The space velocity is 10000 mL/(g-h), and the reaction results are shown in Table 1 and Figure 3.

Example 2

l%Pd-Co ₃ 0 ₄ nanorods: Weigh 10 mmol of cobalt nitrate dissolved in 25 mL of ethylene glycol, gradually heated to 80 °C, and then add 0.1 mol/L NaHC0 dissolved in 100 mL of deionized water. ₃ aqueous solution. After vigorously stirring for 10 min, 15 mL of a solution of 0.021 g of Pd(NO ₃ ) _{2 was added} , and N ₂ aging was continuously introduced thereto. After reacting for 1 h, transfer it to an autoclave, heat it at 160 °C for 3 h, cool to room temperature, centrifuge with deionized water, wash it, vacuum dry at 60 °C for 12 h, then at 400 ° Calcined at C for 4 h. Finally, the calcined body is ground into a fine powder, extruded in a mold under a pressure of 40 kN, and crushed and sieved to obtain catalyst particles having a particle diameter of 40 to 60. The catalytic reaction conditions are: the temperature of the catalytic reaction is 150~450 °C, the pressure is normal pressure; the total flow rate of the reaction is 50 mL/min, wherein the flow rates of the three gases are CH ₄ :0 ₂ :N ₂ =1 : 10:89; The space velocity is 10000 mL/(g-h), and the reaction results are shown in Table 1.

«Example 3

5% Pd-Co ₃ 0 ₄ nanorods: Weigh 5 mmol of cobalt chloride dissolved in 20 mL of ethylene glycol, gradually heated to 70 °C, and then add 0.3 mol/LH dissolved in 50 mL of deionized water. ₄ HC0 ₃ aqueous solution. After vigorously stirring for 10 min, 10 mL of a 0.105 g Pd(NO ₃ ) ₂ solution was added, and N ₂ aging was continuously introduced thereto. After reacting for 1 h, transfer it to an autoclave, heat it at 160 °C for 2 h, cool to room temperature, centrifuge with deionized water, wash it, vacuum dry at 50 °C for 10 h, and finally at 300 ° Calcined at C for 3 h. The calcined body was ground into a fine powder, extruded in a mold under a pressure of 40 kN, and crushed and sieved to obtain catalyst particles having a particle diameter of 40 to 60 mesh. The catalytic reaction conditions are as follows: the temperature of the catalytic reaction is 150 to 450 ° C, and the pressure is normal pressure; the total flow rate of the reaction is 100 mL/min, wherein the flow rates of the three gases are CH ₄ :0 ₂ :N ₂ =1 : 10:89; The space velocity is 60,000 mL/(g-h), and the reaction results are shown in Table 1. Example 4

10% Pd-Co ₃ O ₄ nanorods: Weigh 5mmol of cobalt acetate tetrahydrate (Co(CH ₃ COO) ₂ '4H ₂ 0) dissolved in 15 mL of ethylene glycol, gradually heated to 60 ° C, and then into it A 0.2 mol/L Na ₂ CO ₃ aqueous solution dissolved in 50 mL of deionized water was added. After vigorously stirring for 10 min, 30 mL of 0.105 g of Pd(N0 ₃ ) ₂ solution was added, and N ₂ aging was continuously introduced thereto. After 1.5 h of reaction, transfer it to an autoclave, heat it at 160 ° C for 2 h, cool to room temperature, centrifuge with deionized water, wash it, vacuum dry at 50 ° C for 12 h, and finally at 250 ° C. Roast for 3 h. The calcined body was ground into a fine powder, extruded in a mold under a pressure of 40 kN, and crushed and sieved to obtain catalyst particles having a particle diameter of 40 to 60 mesh. The catalytic reaction conditions are as follows: the temperature of the catalytic reaction is 150 to 450 ° C, and the pressure is normal pressure; the total flow rate of the reaction is 100 mL/min, wherein the flow rates of the three gases are CH ₄ :O ₂ :N ₂ =l: 10:89; The space velocity is 120000 mL/(g-h), and the reaction results are shown in Table 1.

Example 5

9% Pt-Co ₃ 0 ₄ nanorods: Weigh 5 mmol of cobalt sulfate dissolved in 10 mL of propylene glycol, gradually heated to 80 °C, and then add 0.3 mol/L of 00 dissolved in 50 mL of deionized water. ΝΆ,}Aqueous solution. After vigorous stirring for 10 min, 10 mL of 0.0641 g of Pt(NO ₃ ) ₂ solution was added, and N ₂ aging was continuously introduced thereto. After 2 h of reaction, it was transferred to an autoclave at 140°. The water was heated for 3 h, cooled to room temperature, centrifuged with deionized water, washed, vacuum dried at 60 ° C for 10 h, and finally calcined at 300 ° C for 3.5 h. The calcined body was ground to a fine powder at 40 kN. Under the pressure, it is extruded in a mold, and crushed and sieved to obtain catalyst particles having a particle diameter of 40 to 60. The catalytic reaction conditions are as follows: the temperature of the catalytic reaction is 150 to 450 ° C, the pressure is normal pressure; The flow rate was 50 mL/min, and the flow rates of the three gases were CH ₄ :0 ₂ :N ₂ =1:10:89; the space velocity was 30000 mL/(g-h), and the reaction results are shown in Table 1.

Example

3 % Pt-Co ₃ 0 ₄ nanorods: Weigh 2.5 mmol of cobalt acetate tetrahydrate (Co(CH ₃ COO) ₂ '4H ₂ 0) dissolved in 7.5 mL of ethylene glycol and gradually heated to 80 ° C, then A 0.15 mol/L Na ₂ CO ₃ aqueous solution dissolved in 25 mL of deionized water was added thereto. After vigorously stirring for 10 min, 10 mL of a 0.0107 g aqueous solution of Pt(N0 ₃ ) _{2 was added} , and N ₂ aging was continuously introduced thereto. The reaction was carried out for 2 h, transferred to a high pressure reactor, and heated at 140 ° C for 3 h, cooled to room temperature, centrifuged with deionized water, washed, and dried under vacuum at 60 ° C for 10 h to obtain a catalyst precursor, TEM. Figure 4 shows the final calcination at 350 °C for 2 h. The calcined body was ground into a fine powder, extruded in a mold under a pressure of 40 kN, and crushed and sieved to obtain catalyst particles having a particle diameter of 40 to 60 mesh. The catalytic reaction conditions are: the temperature of the catalytic reaction is 150 to 450 ° C, the pressure is normal pressure; the total flow rate of the reaction is 50 mL / min, wherein the flow ratio of the three gases

CH ₄ :0 ₂ :N ₂ =1: 10:89; the space velocity is 10000 mL/(g' h), and the reaction results are shown in Table 1. 3 % Au-Co ₃ 0 ₄ nanorods: Weigh 5 mmol of cobalt acetate tetrahydrate (Co(CH ₃ COO) ₂ '4H ₂ 0) dissolved in 15 mL of ethylene glycol and gradually heated to 80 ° C, then A 0.25 mol/L Na ₂ CO ₃ aqueous solution dissolved in 50 mL of deionized water was added thereto. After vigorously stirring for 10 min, 10 mL of an aqueous solution of 0.0191 g of AuCl _{3 was} added, and N ₂ aging was continuously introduced thereto. After reacting for 3 h, transfer it to an autoclave, heat it at 160 °C for 3 h, cool to room temperature, centrifuge with deionized water, wash it, vacuum dry at 60 °C for 12 h, and finally at 300 ° Calcined at C for 3 h. The calcined body was ground into a fine powder, extruded in a mold under a pressure of 40 kN, and crushed and sieved to obtain catalyst particles having a particle diameter of 40 to 60 mesh. The catalytic reaction conditions are: the temperature of the catalytic reaction is 150~450 °C, the pressure is normal pressure; the total flow rate of the reaction is 75 mL/min, wherein the flow rates of the three gases are CH ₄ :O ₂ :N ₂ =l : 10:89; The space velocity is 30000 mL/(g.h), and the reaction results are shown in Table 1.

Example 8

1% Au-Co ₃ 0 ₄ nanorods: Weigh 5 mmol of cobalt nitrate dissolved in 20 mL of ethylene glycol, gradually heated to 80 °C, and then add 0.2 mol/L Na dissolved in 50 mL of deionized water. ₂ C0 ₃ aqueous solution. After vigorously stirring for 10 min, 10 mL of an aqueous solution of 0.0064 g of AuCl _{3 was} added, and N ₂ aging was continuously introduced thereto. After reacting for one hour, transfer it to an autoclave, heat it at 200 °C for 3 h, cool to room temperature, centrifuge with deionized water, wash it, and dry it under vacuum at 60 °C for 12 h to obtain a catalyst precursor. The TEM image is shown in Figure 5. Finally, it is baked at 300 °C for 4 h. The calcined body was ground into a fine powder, extruded in a mold under a pressure of 40 kN, and crushed and sieved to obtain catalyst particles having a particle diameter of 40 to 60 mesh. The catalytic reaction conditions are as follows: the temperature of the catalytic reaction is 150 to 450 ° C, and the pressure is normal pressure; the total flow rate of the reaction is 50 mL/min, wherein the flow rates of the three gases are CH ₄ :O ₂ :N ₂ =l : 10 :89; The space velocity is 20000 mL/(g-h), and the reaction results are shown in Table 1.

«Example 9

1.5% Ag-Co ₃ 0 ₄ nanorods: Weigh 10 mmol of cobalt acetate tetrahydrate (Co(CH ₃ COO) ₂ '4H ₂ 0) dissolved in 20 mL of butanediol, gradually heated to 60 ° C, then A 0.2 mol/L Na ₂ CO ₃ aqueous solution dissolved in 100 mL of deionized water was added thereto. After vigorously stirring for 10 min, 20 mL of 0.03817 g of AgN0 ₃ aqueous solution was added, and N ₂ aging was continuously introduced thereto. After reacting for 2.5 hours, transfer it to an autoclave, heat it at 140 °C for 2 h, cool to room temperature, centrifuge with deionized water, wash it, vacuum dry at 50 °C for 12 h, and finally at 450 Calcined at °C for 1 h. The calcined body is ground into a fine powder, extruded in a mold under a pressure of 40 kN, and crushed and sieved to obtain catalyst particles having a particle diameter of 40 to 60. The catalytic reaction conditions are: the temperature of the catalytic reaction is 150~450 °C, the pressure is normal pressure; the total flow rate of the reaction is 50 mL/min, wherein the flow rates of the three gases are CH ₄ :O ₂ :N ₂ =l : 10:89; airspeed is 10000 mL/(g-h), The reaction results are shown in Table 1.

3⁄4 example 10

9% Ag-Co ₃ 0 ₄ nanorods: Weigh 5mmol of cobalt acetate tetrahydrate (Co(CH ₃ COO) ₂ '4H ₂ 0) dissolved in 20 mL of diethylene glycol, gradually heated to 120 °C, then A 0.2 mol/L Na ₂ CO ₃ aqueous solution dissolved in 50 mL of deionized water was added thereto. After vigorously stirring for 10 min, 15 mL of 0.05844 g of AgN0 ₃ aqueous solution was added, and N ₂ aging was continuously introduced thereto. After reacting for 3 h, transfer it to an autoclave, heat it at 160 ° C for 3 h, cool to room temperature, centrifuge with deionized water, wash it, vacuum dry at 80 ° C for 8 h, and finally at 350 ° C. Roast for 3h. The calcined body was ground into a fine powder, extruded in a mold under a pressure of 40 kN, and crushed and sieved to obtain catalyst particles having a particle diameter of 40 to 60 mesh. The catalytic reaction conditions are as follows: the temperature of the catalytic reaction is 150 to 450 ° C, and the pressure is normal pressure; the total flow rate of the reaction is 100 mL/min, wherein the flow rates of the three gases are CH ₄ :O ₂ :N ₂ =l: 10:89; The space velocity is 40000 mL/(g-h), and the reaction results are shown in Table 1.

Example 11

5 % Ag-Co ₃ 0 ₄ nanorods: Weigh 5 mmol of cobalt acetate tetrahydrate (Co(CH ₃ COO) ₂ '4H ₂ 0) dissolved in 10 mL of ethylene glycol, gradually heated to 80 ° C, and then into it A 0.2 mol/L Na ₂ CO ₃ aqueous solution dissolved in 50 mL of deionized water was added. After vigorously stirring for 10 min, 20 mL of a 0.0325 g aqueous solution of AgN0 _{3 was added} , and N ₂ aging was continuously introduced thereto. After reacting for 2.5 hours, transfer it to an autoclave, heat it at 160 ° C for 3 h, cool to room temperature, centrifuge with deionized water, wash it, vacuum dry at 50 ° C for 12 h, and finally at 250 ° C. Baked for 4 h. The calcined body is ground into a fine powder, extruded in a mold under a pressure of 40 kN, and crushed and sieved to obtain catalyst particles having a particle diameter of 40 to 60. The catalytic reaction conditions are as follows: the temperature of the catalytic reaction is 150 to 450 ° C, and the pressure is normal pressure; the total flow rate of the reaction is 100 mL/min, wherein the flow rates of the three gases are CH ₄ :O ₂ :N ₂ =l: 10:89; the space velocity is 40,000 mL/(g-h), and the reaction results are shown in Table 1.

3⁄4 example 12

3% PdAu(5:l)-Co ₃ 0 ₄ nanorods: Weigh 5mmol of cobalt acetate tetrahydrate (Co(CH ₃ COO) ₂ '4H ₂ 0) dissolved in 15 mL of ethylene glycol and gradually heated to 80° C, then a 0.2 mol/L Na ₂ CO ₃ aqueous solution dissolved in 50 mL of deionized water was added thereto. After vigorously stirring for 10 min, 10 mL of a mixed aqueous solution of 0.0319 g of K ₂ PdCl ₄ and 0.0032 g of AuCl _{3 was added} , and Ar was continuously introduced thereto. After reacting for one hour, it was transferred to an autoclave, heated at 160 ° C for 3 h, cooled to room temperature, centrifuged with deionized water, washed, and dried under vacuum at 60 ° C for 12 h to obtain a catalyst precursor. The TEM image is shown in Figure 6a and finally calcined at 300 °C for 3 h. The calcined body is ground into a fine powder, extruded in a mold under a pressure of 40 kN, and crushed and sieved to obtain a catalyst particle having a particle diameter of 40 to 60, TEM See Figure 6b. The catalytic reaction conditions are: the temperature of the catalytic reaction is 150~450 °C, the pressure is normal pressure; the total flow rate of the reaction is lOOmL/min, wherein the flow rates of the three gases are CH ₄ :O ₂ :N ₂ =l :10 : 89; The space velocity is 60,000 mL / (g. h), and the reaction results are shown in Table 1 and Figure 7.

3⁄4St example 13

3% PdAu(5: l)-Co ₃ 0 ₄ nanorods (water resistance): Weigh 5 mmol of cobalt acetate tetrahydrate (Co(CH ₃ COO) ₂ '4H ₂ 0) dissolved in 15 mL of ethylene glycol. The mixture was gradually heated to 80 ° C, and then a 0.2 mol/L Na ₂ CO ₃ aqueous solution dissolved in 50 mL of deionized water was added thereto. After vigorously stirring for 10 min, 10 mL of a mixed aqueous solution of 0.0319 g of K ₂ PdCl ₄ and 0.0032 g of AuCl _{3 was added} , and Ar was continuously introduced thereto. After reacting for one hour, transfer it to an autoclave, heat it at 160 °C for 3 h, cool to room temperature, centrifuge with deionized water, wash it, vacuum dry at 60 °C for 12 h, and finally at 300 Calcined at °C for 3 h. The calcined body was ground into a fine powder, extruded in a mold under a pressure of 40 kN, and crushed and sieved to obtain catalyst particles having a particle diameter of 40 to 60 mesh. The catalytic reaction conditions are: the temperature of the catalytic reaction is 150~450 °C, the pressure is normal pressure; the total flow rate of the reaction is 50mL/min, wherein the flow rates of the three gases CH ₄ , 0 ₂ , N ₂ are CH ₄ : O ₂ :N ₂ =l : 10:89; water vapor content of 5%, space velocity of 20000 mL / (g. h), the reaction results are shown in Table 1.

Example 14

3% PdAu(3: l)-Co ₃ 0 ₄ nanorods: Weigh 5 mmol of cobalt acetate tetrahydrate (Co(CH ₃ COO) ₂ '4H ₂ 0) dissolved in 15 mL of ethylene glycol and gradually heated to 80 °C, then a 0.2 mol/L Na ₂ CO ₃ aqueous solution dissolved in 50 mL of deionized water was added thereto. After vigorously stirring for 10 min, 10 mL of a mixed aqueous solution of 0.0255 g of K ₂ PdCl ₄ and 0.0064 g of AuCl _{3 was added} , and Ar was continuously introduced thereto. After reacting for one hour, transfer it to an autoclave, heat it at 160 °C for 3 h, cool to room temperature, centrifuge with deionized water, wash it, vacuum dry at 60 °C for 12 h, and finally at 300 Calcined at °C for 3 h. The calcined body was ground into a fine powder, extruded in a mold under a pressure of 40 kN, and crushed and sieved to obtain catalyst particles having a particle diameter of 40 to 60 mesh. The catalytic reaction conditions are as follows: the temperature of the catalytic reaction is 150 to 450 ° C, and the pressure is normal pressure; the total flow rate of the reaction is 100 mL/min, wherein the flow rates of the three gases are

CH ₄ :0 ₂ :N ₂ =1 : 10:89 ; The space velocity is 60000 mL/(g'h), and the reaction results are shown in Table 1.

3% PdPt(l: l)-Co ₃ 0 ₄ nanorods: Weigh 5 mmol of cobalt acetate tetrahydrate (Co(CH ₃ COO) ₂ '4H ₂ 0) dissolved in 15 mL of ethylene glycol and gradually heated to 80 °C, then a 0.2 mol/L Na ₂ CO ₃ aqueous solution dissolved in 50 mL of deionized water was added thereto. After vigorously stirring for 10 min, 10 mL of a mixed aqueous solution of 0.0192 g of K ₂ PdCl ₄ and 0.0130 g of Pt(NO ₃ ) _{2 was added} , and Ar was continuously introduced thereto. After 1.5 hours of reaction, it was transferred to an autoclave, heated at 160 ° C for 3 h, cooled to room temperature, centrifuged with deionized water, washed, and dried under vacuum at 60 ° C for 12 h. Finally, it was baked at 300 °C for 3 h. The calcined body was ground into a fine powder, extruded in a mold under a pressure of 40 kN, and crushed and sieved to obtain catalyst particles having a particle diameter of 40 to 60 mesh. The catalytic reaction conditions are: catalyst mass 0.1g, catalytic reaction temperature is 150~450 °C, pressure is normal pressure; total reaction flow rate is 75mL/min, wherein the flow rates of these three gases are CH ₄ :0 ₂ :N ₂ =1 : 10:89; the space velocity is 30000 mL/(g'h), and the reaction results are shown in Table 1.

Example 16

3% PdPt(3: l)-Co ₃ 0 ₄ nanorods: Weigh 5 mmol of cobalt acetate tetrahydrate (Co(CH ₃ COO) ₂ '4H ₂ 0) dissolved in 15 mL of ethylene glycol and gradually heated to 60 °C, then a 0.2 mol/L Na ₂ CO ₃ aqueous solution dissolved in 50 mL of deionized water was added thereto. After vigorously stirring for 10 min, 10 mL of a mixed aqueous solution of 0.0255 g of K ₂ PdCl ₄ and 0.0071 g of Pt(NO ₃ ) _{2 was added} , and Ar was continuously introduced thereto. After reacting for one hour, transfer it to an autoclave, heat it at 160 °C for 3 h, cool to room temperature, centrifuge with deionized water, wash it, vacuum dry at 60 °C for 12 h, and finally at 400 Calcined at °C for 3 h. The calcined body was ground into a fine powder, extruded in a mold under a pressure of 40 kN, and crushed and sieved to obtain catalyst particles having a particle diameter of 40 to 60 mesh. The catalytic reaction conditions are: the temperature of the catalytic reaction is 150 to 450 ° C, the pressure is normal pressure; the total flow rate of the reaction is 75 mL / min, wherein the flow ratio of the three gases

CH ₄ :0 ₂ :N ₂ =1 : 10:89 ; The space velocity is 30000 mL/(g'h), and the reaction results are shown in Table 1.

Example 17

3% PdAg(3: l)-Co ₃ 0 ₄ nanorods: Weigh 5 mmol of cobalt acetate tetrahydrate (Co(CH ₃ COO) ₂ '4H ₂ 0) dissolved in 15 mL of ethylene glycol and gradually heated to 80 °C, then a 0.25 mol/L Na ₂ CO ₃ aqueous solution dissolved in 50 mL of deionized water was added thereto. After vigorously stirring for 10 min, 10 mL of a mixed aqueous solution of 0.0255 g of K ₂ PdCl ₄ and 0.0065 g of Ag(N0 ₃ ) _{2 was added} , and Ar was continuously introduced thereto. After reacting for one hour, transfer it to an autoclave, heat it at 160 °C for 3 h, cool to room temperature, centrifuge with deionized water, wash it, vacuum dry at 60 °C for 12 h, and finally at 250 Calcined at °C for 5 h. The calcined body was ground into a fine powder, extruded in a mold under a pressure of 40 kN, and crushed and sieved to obtain catalyst particles having a particle diameter of 40 to 60 mesh. The catalytic reaction conditions are: the temperature of the catalytic reaction is 150~450 °C, the pressure is normal pressure; the total flow rate of the reaction is 75 mL/min, wherein the flow ratio of the three gases

CH ₄ :0 ₂ :N ₂ =1 : 10:89; the space velocity is 30000 mL/(g' h), and the reaction results are shown in Table 1.

3⁄4 example 18

9 % AuAg(3: l)-Co ₃ 0 ₄ nanorods: weigh 5 mmol of cobalt acetate tetrahydrate (Co(CH ₃ COO) ₂ '4H ₂ 0) dissolved in 15 mL of ethylene glycol and gradually heated to 80 °C, then a 0.2 mol/L Na ₂ CO ₃ aqueous solution dissolved in 50 mL of deionized water was added thereto. After vigorously stirring for 10 min, 10 mL of a mixed aqueous solution of 0.0429 g of AuCl ₃ and 0.0146 g of Ag(N0 ₃ ) _{2 was added} , and Ar was continuously introduced thereto. After reacting for one hour, transfer it to the autoclave, After heating at 160 °C for 3 h, it was cooled to room temperature, centrifuged with deionized water, washed, vacuum dried at 60 °C for 12 h, and finally calcined at 300 °C for 3 h. The calcined body was ground into a fine powder, extruded in a mold under a pressure of 40 kN, and crushed and sieved to obtain catalyst particles having a particle diameter of 40 to 60 mesh. The catalytic reaction conditions are: the temperature of the catalytic reaction is 150 to 450 ° C, the pressure is normal pressure; the total flow rate of the reaction is 75 mL / min, wherein the flow ratio of the three gases

CH ₄ :0 ₂ :N ₂ =1 : 15:84 ; The space velocity is 30000 mL/(g' h), and the reaction results are shown in Table 1.

»Example 19

6 % PtAg(3: l)-Co ₃ 0 ₄ nanorods: Weigh 5 mmol of cobalt acetate tetrahydrate (Co(CH ₃ COO) ₂ '4H ₂ 0) dissolved in 15 mL of ethylene glycol and gradually heated to 80 °C, followed by the addition of a 0.2 mol/L Na ₂ CO ₃ aqueous solution dissolved in 50 mL of deionized water. After vigorously stirring for 10 min, 10 mL of a mixed aqueous solution of 0.0284 g of Pt(NO ₃ ) ₂ and 0.0130 g of Ag(N0 ₃ ) _{2 was added} , and Ar was continuously introduced thereto. After reacting for one hour, transfer it to an autoclave, heat it at 160 °C for 3 h, cool to room temperature, centrifuge with deionized water, wash it, vacuum dry at 60 °C for 12 h, and finally at 300 Calcined at °C for 3 h. The calcined body was ground into a fine powder, extruded in a mold under a pressure of 40 kN, and crushed and sieved to obtain catalyst particles having a particle diameter of 40 to 60 mesh. The catalytic reaction conditions are as follows: the temperature of the catalytic reaction is 150 to 450 ° C, and the pressure is normal pressure; the total flow rate of the reaction is 75 mL/min, wherein the flow rates of the three gases are CH ₄ : O ₂ : N ₂ = l : 10:89; The space velocity is 30000 mL/(g-h), and the reaction results are shown in Table 1.

Example 20

6 % PtAu(3: l)-Co ₃ 0 ₄ nanorods: Weigh 5 mmol of cobalt acetate tetrahydrate (Co(CH ₃ COO) ₂ '4H ₂ 0) dissolved in 15 mL of ethylene glycol and gradually heated to 80 °C, then a 0.2 mol/L Na ₂ CO ₃ aqueous solution dissolved in 50 mL of deionized water was added thereto. After vigorously stirring for 10 min, 10 mL of a mixed aqueous solution of 0.0214 g of Pt(N0 ₃ ) ₂ and 0.0190 g of AuCl _{3 was added} , and Ar was continuously introduced thereto. After reacting for one hour, transfer it to an autoclave, heat it at 160 °C for 4 h, cool to room temperature, centrifuge with deionized water, wash it, vacuum dry at 60 °C for 12 h, and finally at 350 Calcined at °C for 3 h. The calcined body was ground into a fine powder, extruded in a mold under a pressure of 40 kN, and crushed and sieved to obtain catalyst particles having a particle diameter of 40 to 60 mesh. The catalytic reaction conditions are: the temperature of the catalytic reaction is 150~450 °C, the pressure is normal pressure; the total flow rate of the reaction is 75 mL/min, wherein the flow ratio of the three gases

CH ₄ :0 ₂ :N ₂ =1 :5:94 ; The space velocity is 30000 mL/(g' h), and the reaction results are shown in Table 1.

3⁄43⁄4 cases 21

3% PdAu(l : 10)-Co ₃ O ₄ nanorods: Weigh 5 mmol of cobalt acetate tetrahydrate (Co(CH ₃ COO) ₂ '4H ₂ 0) dissolved in 15 mL of ethylene glycol and gradually heated to 80 °C, then a 0.2 mol/L Na ₂ CO ₃ aqueous solution dissolved in 50 mL of deionized water was added thereto. After vigorous stirring for 10 min, 10 mL of 0.0034 g K ₂ PdCl ₄ and 0.0173 g AuCl _{3 were added} . An aqueous solution was passed through and Ar was continuously introduced thereinto. After reacting for one hour, transfer it to an autoclave, heat it at 160 °C for 3 h, cool to room temperature, centrifuge with deionized water, wash it, vacuum dry at 60 °C for 12 h, and finally at 300 Calcined at °C for 3 h. The calcined body was ground into a fine powder, extruded in a mold under a pressure of 40 kN, and crushed and sieved to obtain catalyst particles having a particle diameter of 40 to 60 mesh. The catalytic reaction conditions are: the temperature of the catalytic reaction is 150~450 °C, the pressure is normal pressure; the total flow rate of the reaction is 50 mL/min, wherein the flow ratio of the three gases

CH ₄ :0 ₂ :N ₂ =1 : 10:89 ; The space velocity is 20000 mL/(g'h), and the reaction results are shown in Table 1. Table 1 Catalysts of Examples 1 to 20 catalyzed the combustion reaction of formazan

Embodiment 21 0 9 30 52 78 93 100 The above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. It should be noted that those skilled in the art will not Numerous modifications and additions may be made without departing from the method of the invention, and such modifications and additions are also considered to be within the scope of the invention. The equivalents of the changes, modifications, and evolutions that can be made by the above-disclosed technical contents are all those skilled in the art without departing from the spirit and scope of the present invention. Equivalent embodiments; at the same time, any changes, modifications and evolutions of any equivalent changes made to the above-described embodiments in accordance with the essential art of the present invention are still within the scope of the technical solutions of the present invention.

Claims

The present invention relates to a supported cobalt tetraoxide catalyst characterized by comprising the following components: noble metal, noble metal oxide and tricobalt tetroxide, the ratio of the mass of the precious metal element to the total mass of the precious metal element and Co304 is 1 to 10:100, The supported cobalt trioxide catalyst is a one-dimensional structure. The supported tricobalt catalyst according to claim 1, wherein the noble metal element is one or two selected from the group consisting of Pd, Pt, Au, and Ag. The supported tricobalt catalyst according to claim 2, wherein when the precious metal elements are two, the mass ratio of the two noble metal elements is 1:10-10:1. A method for preparing a supported tricobalt catalyst according to any one of claims 1 to 3, characterized in that, in the diol system, the cobalt salt and the precipitant aqueous solution are coprecipitated according to the composition ratio of the catalyst. Further, a noble metal salt solution is added, and the supported tricobalt catalyst is obtained by hydrothermal, drying and calcination. The preparation method according to claim 1, comprising the steps of: 1) coprecipitating: mixing a cobalt salt and a diol, adding an aqueous solution of a precipitating agent, adding a precious metal salt solution after stirring, and aging; 2) Step 1) The obtained solution is hydrothermally dried, calcined and calcined to obtain the supported tricobalt catalyst. The preparation method according to claim 4 or 5, wherein the ratio of the cobalt salt, the precipitant and the glycol is 10 mmol: 10-30 mmol: 20 to 40 mL. l~0.3mol/L。 The concentration of the aqueous solution of the precipitant is 0. l ~ 0.3mol / L. The preparation method according to claim 4 or 5, wherein the reaction temperature of the coprecipitation is 60 to 120 ° C, and the reaction time of the coprecipitation is 1 to 3 hours. The preparation method according to claim 4 or 5, wherein the precious metal salt solution is added and a gas is introduced for aging. The preparation method according to claim 4 or 5, wherein the hydrothermal condition is: hydrothermal temperature is 140 to 200 ° C, and hydrothermal time is 2 to 4 h.

The method according to claim 4 or 5, wherein the drying condition is a drying temperature of 50 to 80 ° C and a drying time of 8 to 12 hours.

The preparation method according to claim 4 or 5, wherein the calcination conditions are: calcination temperature is 250 450 ° C, and calcination time is 1 to 5 hours.

3. Use of a supported tricobalt catalyst according to any one of claims 1 to 3, characterized in that it is used for the catalytic combustion of formazan.

The use according to claim 13, wherein the formazan catalytic combustion reaction condition is: the reaction temperature is 150~ 450. C, the reaction pressure is normal pressure; the total flow rate of the reaction is 50~100 mL/min, the flow ratio of CH ₄ , 0 ₂ and N ₂ is 1:5-15:84-94; the space velocity is 10000~120000 mL/ (g-h).