阅读说明：本技术 一种制新能源甲烷气体催化剂的制备方法 (Preparation method of catalyst for preparing new energy methane gas ) 是由 谭春强 于 2021-08-23 设计创作，主要内容包括：本发明公开了一种制新能源甲烷气体催化剂的制备方法,其制备方法包括将镧盐、铁盐和钴盐混合研磨,然后加入到去离子水中,磁力搅拌,然后加入凝胶物质,然后将溶液移至陶瓷蒸发皿并置于电炉中,收集粉末产物；将粉末产物置于管式炉当中,在氮气氛围下,一定温度下焙烧2～5h,得到前驱体LaFe-(x)Co-(1-x)O-(3),将前驱体、L-精氨酸、多巴胺和氧化石墨烯依次加入到去离子水当中,超声搅拌,然后加入乙二醇,将混合液移至反应釜当中,放置于烘箱中,在一定温度下水热合成,过滤,干燥,然后置于管式炉中,氮气氛围下,焙烧1～2h,得到该改性催化剂LaFe-(x)Co-(1-)-(x)O-(3)。本发明改性催化剂活性位点暴露增强,因而更高效地催化降解甲烷。(The invention discloses a preparation method of a new energy methane gas catalyst, which comprises the steps of mixing and grinding lanthanum salt, ferric salt and cobalt salt, adding the mixture into deionized water, magnetically stirring, adding a gel substance, transferring the solution to a ceramic evaporation vessel, placing the ceramic evaporation vessel in an electric furnace, and collecting a powder product; the powder product was placed in a tube furnace under nitrogenRoasting for 2-5 h at a certain temperature in an atmosphere to obtain a precursor LaFe x Co 1‑x O 3 Sequentially adding a precursor, L-arginine, dopamine and graphene oxide into deionized water, ultrasonically stirring, adding ethylene glycol, transferring the mixed solution into a reaction kettle, placing the reaction kettle into an oven, carrying out hydrothermal synthesis at a certain temperature, filtering, drying, placing the reaction kettle into a tubular furnace, and roasting for 1-2 hours in a nitrogen atmosphere to obtain the modified catalyst LaFe x Co 1‑ x O 3 . The modified catalyst has enhanced active site exposure, thereby more efficiently catalyzing and degrading methane.)

1. A preparation method of a catalyst for preparing new energy methane gas is characterized by comprising the following steps:

s1: preparation of precursor LaFe_xCo_1-xO₃；

S2: sequentially adding a precursor, L-arginine, dopamine and graphene oxide into deionized water, ultrasonically stirring for 30min, then adding ethylene glycol, transferring the mixed solution into a reaction kettle, placing the reaction kettle into an oven, carrying out hydrothermal synthesis at 180-220 ℃ for 2-6 h, filtering, drying at 80 ℃, then placing the reaction kettle into a tubular furnace, roasting at 500-900 ℃ for 1-2 h under the nitrogen atmosphere to obtain the modified catalyst LaFe_xCo_1-xO₃；

Wherein, the precursor preparation comprises the following steps:

1) mixing and grinding lanthanum salt, ferric salt and cobalt salt, adding the mixture into deionized water, magnetically stirring the mixture for 30-60 min, adding a gel substance, continuously stirring the mixture for 2h at room temperature, transferring the solution to a ceramic evaporation vessel, placing the ceramic evaporation vessel in an electric furnace of 800W, and collecting a powder product;

2) placing the powder product in a tube furnace, heating to 400-500 ℃ at a heating rate of 2 ℃/min under a nitrogen atmosphere, preserving heat for 2h at the temperature, heating to 700-1000 ℃ at a heating rate of 1.5 ℃/min, and roasting for 2-5 h to obtain a precursor LaFe_xCo_1-xO₃。

2. The preparation method of the catalyst for preparing the new energy methane gas according to claim 1, wherein the mass ratio of the precursor, the L-arginine, the dopamine and the graphene oxide is 1: 0.28-0.33: 0.1-0.13: 0.2-0.4.

3. The preparation method of the catalyst for preparing the new energy methane gas according to claim 1, wherein the mass-to-volume ratio of the precursor to the ethylene glycol is 1g: 1-3 mL.

4. The method as claimed in claim 1, wherein the lanthanum salt is any one of lanthanum nitrate or lanthanum sulfate.

5. The preparation method of the catalyst for preparing the new energy methane gas according to claim 1, wherein the iron salt is any one of ferric nitrate, ferric sulfate or ferric acetate.

6. The method for preparing a catalyst for preparing methane gas as a new energy source of claim 1, wherein the cobalt salt is any one of cobalt nitrate, cobalt acetate or cobalt sulfate.

7. The method for preparing a catalyst for preparing methane gas as a new energy source according to claim 1, wherein the molar ratio of lanthanum salt, iron salt and cobalt salt is 1: x:1-x, and 0< x < 1.

8. The method for preparing a catalyst for preparing methane gas as a new energy source of claim 1, wherein the gel substance is any one of citric acid monohydrate or urea.

9. The method for preparing a catalyst for preparing methane gas as a new energy source according to claim 1, wherein the molar ratio of the lanthanum salt to the gel substance is 1: 0.02-0.21.

Technical Field

The invention belongs to the technical field of methane catalysis catalysts, and particularly relates to a preparation method of a catalyst for preparing new energy methane gas.

Background

With the improvement of environmental awareness of people, the clean energy natural gas taking methane as a main component has obvious advantages in the process of energy development and use, but the use of the clean energy natural gas brings problems of environmental pollution and the like while bringing development and progress to the world. Among the hydrocarbons, methane is the most difficult to oxidize, and this low reactivity is related to the symmetry of its molecules. The traditional methane combustion needs to be carried out at high temperature above 1500 ℃, so that NO which seriously pollutes the environment is generated_xGaseous pollutants such as CO; and methane itself is a greenhouse gas with greenhouse effect more than the same volume of CO₂25 times larger. The heterogeneous catalytic combustion of methane can improve the energy utilization rate of methane and reduce the emission of pollutants, so that the catalytic combustion of methane draws greater attention in the aspects of energy application and reduction of environmental pollution.

Chinese patent CN109317154A discloses a preparation method of perovskite type catalytic material, in the invention, by adding metal ions to optimize the perovskite metal oxide catalyst, the defects of the perovskite metal oxide catalyst prepared by the traditional method are improved, the specific surface area of the catalyst is increased, and the efficiency of the catalyst for catalyzing methane is improved, but the catalytic activity of the catalyst prepared by the invention is still poor, and the T is less than the T_50％Above 430 ℃ of T_50％Above 480 c, the reaction rate of methane on the catalyst is shown to be slow.

Disclosure of Invention

The invention aims to provide a preparation method of a catalyst for preparing new energy methane gas, which comprises the following steps:

s1: preparation of precursor LaFe_xCo_1-xO₃。

S2: sequentially adding a precursor, L-arginine, dopamine and graphene oxide into deionized water, ultrasonically stirring for 30min, then adding ethylene glycol, transferring the mixed solution into a reaction kettle, placing the reaction kettle into an oven, carrying out hydrothermal synthesis at 180-220 ℃ for 2-6 h, filtering, drying at 80 ℃, then placing the reaction kettle into a tubular furnace, roasting at 500-900 ℃ for 1-2 h in a nitrogen atmosphere, and finally carrying out ultrasonic wave dryingh, obtaining the modified catalyst LaFe_xCo_1-xO₃。

Preferably, the mass ratio of the precursor, the L-arginine, the dopamine and the graphene oxide is 1: 0.28-0.33: 0.1-0.13: 0.2-0.4.

Preferably, the mass-to-volume ratio of the precursor to the glycol is 1g: 1-3 mL.

Preferably, the preparation of the precursor comprises:

1) mixing and grinding lanthanum salt, ferric salt and cobalt salt, adding the mixture into deionized water, magnetically stirring for 30-60 min, adding a gel substance, continuously stirring for 2h at room temperature, transferring the solution to a ceramic evaporation vessel, placing the ceramic evaporation vessel in an electric furnace of 800W, and collecting a powder product.

2) Placing the powder product in a tube furnace, heating to 400-500 ℃ at a heating rate of 2 ℃/min under a nitrogen atmosphere, preserving heat for 2h at the temperature, heating to 700-1000 ℃ at a heating rate of 1.5 ℃/min, and roasting for 2-5 h to obtain a precursor LaFe_xCo_1-xO₃。

Preferably, the lanthanum salt is any one of lanthanum nitrate or lanthanum sulfate.

Preferably, the iron salt is any one of ferric nitrate, ferric sulfate or ferric acetate.

Preferably, the cobalt salt is any one of cobalt nitrate, cobalt acetate and cobalt sulfate.

Preferably, the molar ratio of the lanthanum salt, the iron salt and the cobalt salt is 1: x:1-x, wherein 0< x < 1.

Preferably, the gel substance is either citric acid monohydrate or urea.

Preferably, the molar ratio of the lanthanum salt to the gel substance is 1: 0.02-0.21.

The invention has the following beneficial effects:

(1) the catalyst prepared by the invention is modified by post-modification with L-arginine, dopamine and graphene oxide, wherein the L-arginine, dopamine and graphene oxide are green and nontoxic and contain abundant hydroxyl (-OH) and carboxyl (-COOH) functional groups, and the functional groups play an important role in coordination with metal ions, thereby being beneficial to improving the methane catalytic activity of the catalyst.

(2) The invention applies a hydrothermal synthesis method and improves the defect that the perovskite catalyst prepared by the traditional method causes the agglomeration of catalyst particles by the hydrothermal method through temperature programmed heat treatment roasting, and the exposure of active sites is obviously enhanced, thereby more efficiently catalyzing and degrading methane.

Drawings

FIG. 1 is an XRD pattern of the modified catalyst prepared in example 1 of the present invention.

Detailed Description

The following examples are provided for the purpose of illustration, and the present invention is not limited to the following examples.

Example 1

A preparation method of a catalyst for preparing new energy methane gas specifically comprises the following steps:

s1: mixing and grinding lanthanum nitrate, ferric nitrate and cobalt nitrate, then adding the mixture into deionized water, wherein the molar ratio of the lanthanum nitrate to the ferric nitrate to the cobalt nitrate is 1:0.1:0.9, magnetically stirring the mixture for 30min, then adding citric acid monohydrate, wherein the molar ratio of the lanthanum nitrate to the citric acid monohydrate is 1:0.02, continuously stirring the mixture for 2h at room temperature, then transferring the solution to a ceramic evaporating dish, placing the ceramic evaporating dish in an electric furnace of 800W, and collecting powder products.

S2: placing the powder product in a tube furnace, heating to 400 ℃ at a heating rate of 2 ℃/min under the nitrogen atmosphere, preserving heat for 2h at the temperature, then heating to 700 ℃ at a heating rate of 1.5 ℃/min, and roasting for 2h to obtain a precursor LaFe_0.1Co_0.9O₃。

S3: sequentially adding a precursor, L-arginine, dopamine and graphene oxide into deionized water, wherein the precursor and the LCarrying out ultrasonic stirring for 30min, then adding glycol, wherein the mass volume ratio of the precursor to the glycol is 1g:1mL, transferring the mixed solution into a reaction kettle, placing the reaction kettle into a drying oven, carrying out hydrothermal synthesis for 2h at 180 ℃, filtering, drying at 80 ℃, then placing the reaction kettle into a tubular furnace, roasting for 1h at 500 ℃ in a nitrogen atmosphere to obtain the modified catalyst LaFe, wherein the mass ratio of arginine to dopamine to graphene oxide is 1:0.28:0.1:0.2_0.1Co_0.9O₃。

Example 2

A preparation method of a catalyst for preparing new energy methane gas specifically comprises the following steps:

s1: mixing and grinding lanthanum sulfate, ferric sulfate and cobalt acetate, adding the mixture into deionized water, wherein the molar ratio of the lanthanum sulfate to the ferric sulfate to the cobalt acetate is 1:0.3:0.7, magnetically stirring the mixture for 60min, adding urea, wherein the molar ratio of the lanthanum sulfate to the urea is 1:0.21, continuously stirring the mixture for 2h at room temperature, transferring the solution to a ceramic evaporation vessel, placing the ceramic evaporation vessel in an electric furnace of 800W, and collecting powder products.

S2: placing the powder product in a tube furnace, heating to 500 ℃ at a heating rate of 2 ℃/min under the nitrogen atmosphere, preserving heat for 2h at the temperature, then heating to 1000 ℃ at a heating rate of 1.5 ℃/min, and roasting for 5h to obtain a precursor LaFe_0.3Co_0.7O₃。

S3: sequentially adding a precursor, L-arginine, dopamine and graphene oxide into deionized water, wherein the mass ratio of the precursor to the L-arginine to the dopamine to the graphene oxide is 1:0.33:0.13:0.4, ultrasonically stirring for 30min, then adding ethylene glycol, wherein the mass volume ratio of the precursor to the ethylene glycol is 1g:3mL, transferring the mixed solution into a reaction kettle, placing the reaction kettle into an oven, carrying out hydrothermal synthesis at 220 ℃ for 6h, filtering, drying at 80 ℃, then placing the reaction kettle into a tubular furnace, and roasting at 900 ℃ for 2h under the nitrogen atmosphere to obtain the modified catalyst LaFe_0.3Co_0.7O₃。

Example 3

A preparation method of a catalyst for preparing new energy methane gas specifically comprises the following steps:

s1: mixing and grinding lanthanum nitrate, iron acetate and cobalt sulfate, adding the mixture into deionized water, wherein the molar ratio of the lanthanum nitrate to the iron acetate to the cobalt sulfate is 1:0.4:0.6, magnetically stirring the mixture for 40min, adding citric acid monohydrate, wherein the molar ratio of the lanthanum nitrate to the citric acid monohydrate is 1:0.09, continuously stirring the mixture for 2h at room temperature, transferring the solution to a ceramic evaporating dish, placing the ceramic evaporating dish in an electric furnace of 800W, and collecting a powder product.

S2: placing the powder product in a tube furnace, heating to 450 ℃ at a heating rate of 2 ℃/min under the nitrogen atmosphere, preserving heat for 2h at the temperature, then heating to 800 ℃ at a heating rate of 1.5 ℃/min, and roasting for 3h to obtain a precursor LaFe_0.4Co_0.6O₃。

S3: sequentially adding a precursor, L-arginine, dopamine and graphene oxide into deionized water, wherein the mass ratio of the precursor to the L-arginine to the dopamine to the graphene oxide is 1:0.3:0.11:0.28, ultrasonically stirring for 30min, then adding ethylene glycol, wherein the mass volume ratio of the precursor to the ethylene glycol is 1g:2mL, transferring the mixed solution into a reaction kettle, placing the reaction kettle into an oven, carrying out hydrothermal synthesis at 200 ℃ for 4h, filtering, drying at 80 ℃, then placing the reaction kettle into a tubular furnace, and roasting at 600 ℃ for 1.5h under the nitrogen atmosphere to obtain the modified catalyst LaFe_0.4Co_0.6O₃。

Example 4

A preparation method of a catalyst for preparing new energy methane gas specifically comprises the following steps:

s1: mixing and grinding lanthanum nitrate, ferric sulfate and cobalt sulfate, adding the mixture into deionized water, wherein the molar ratio of the lanthanum nitrate to the ferric sulfate to the cobalt sulfate is 1:0.6:0.4, magnetically stirring the mixture for 50min, adding urea, wherein the molar ratio of the lanthanum nitrate to the urea is 1:0.18, continuously stirring the mixture for 2h at room temperature, transferring the solution to a ceramic evaporation vessel, placing the ceramic evaporation vessel into an electric furnace of 800W, and collecting powder products.

S2: putting the powder product into a tube furnace, heating to 500 ℃ at a heating rate of 2 ℃/min under the nitrogen atmosphere, preserving heat for 2h at the temperature, then heating to 900 ℃ at a heating rate of 1.5 ℃/min,roasting for 2-5 h to obtain a precursor LaFe_0.6Co_0.4O₃。

S3: sequentially adding a precursor, L-arginine, dopamine and graphene oxide into deionized water, wherein the mass ratio of the precursor to the L-arginine to the dopamine to the graphene oxide is 1:0.3:0.12:0.36, ultrasonically stirring for 30min, then adding ethylene glycol, wherein the mass volume ratio of the precursor to the ethylene glycol is 1g:3mL, transferring the mixed solution into a reaction kettle, placing the reaction kettle into an oven, carrying out hydrothermal synthesis at 210 ℃ for 5h, filtering, drying at 80 ℃, then placing the reaction kettle into a tubular furnace, and roasting at 800 ℃ for 2h under the nitrogen atmosphere to obtain the modified catalyst LaFe_0.6Co_0.4O₃。

Performance test experiments:

the modified catalyst LaFe prepared in the example 1-4_xCo_1-xO₃Testing the catalytic activity by adopting a fixed bed reactor, wherein the dosage of the catalyst is 1mL, and the volume fraction of the reaction gas is CH₄:1 percent; air: 99%, the mixed gas rate is 80mL/min, the methane inlet and tail gas concentrations are analyzed on line by gas chromatography, the sample inlet temperature is 150 ℃, the FID detector temperature is 150 ℃, and the test results are shown in Table 1, Table 1

As can be seen from Table 1, the modified catalysts prepared in examples 1 to 4 have methane catalysis performance T_50％All at about 350 ℃ and T_90％All at about 421 ℃, and is mixed with unmodified catalyst LaFe_xCo_1-xO₃Compared with, T_50％All at about 410 ℃ and T_90％The temperature is about 522 ℃, which shows that methane has faster reaction rate on the catalyst, so the modified catalyst prepared by the invention shows more excellent methane catalytic activity.