阅读说明：本技术 一种纳米碳负载钴氮碳催化材料及其制备方法和应用 (Nano-carbon-loaded cobalt nitrogen carbon catalytic material and preparation method and application thereof ) 是由 齐伟 曹天龙 于 2020-04-24 设计创作，主要内容包括：本发明公开了一种纳米碳负载钴氮碳催化材料及其制备方法和应用,属于丙烷脱氢反应催化剂技术领域。纳米碳与钴氮碳物种的复合是通过钴盐前驱体与邻二氮菲配体发生络合原位浸渍在纳米碳表面后再进行煅烧和酸洗的过程来完成。这种复合材料可以很大程度的解决纳米碳催化性能低和钴氮碳活性物种利用效率低、稳定性差的问题。将所述催化材料作为丙烷脱氢反应的催化剂,在无水无氧常压的条件下催化丙烷直接脱氢生成丙烯,催化剂的使用温度为400～600℃；该催化剂性能稳定,在直接脱氢反应中可以得到高的催化活性和高的丙烯选择性,在反应过程中不易积碳,制备方法简便,原料易得。(The invention discloses a nano-carbon supported cobalt nitrogen carbon catalytic material, and a preparation method and application thereof, and belongs to the technical field of propane dehydrogenation reaction catalysts. The compounding of the nano carbon and the cobalt nitrogen carbon species is completed through the processes of complexing the cobalt salt precursor and the o-diazaphenanthrene ligand, in-situ soaking the cobalt salt precursor and the o-diazaphenanthrene ligand on the surface of the nano carbon, and then calcining and pickling the nano carbon and the cobalt nitrogen carbon. The composite material can solve the problems of low catalytic performance of nano carbon, low utilization efficiency of cobalt nitrogen carbon active species and poor stability to a great extent. The catalytic material is used as a catalyst for propane dehydrogenation reaction, propane is catalyzed under the conditions of no water, no oxygen and normal pressure to be directly dehydrogenated to generate propylene, and the use temperature of the catalyst is 400-600 ℃; the catalyst has stable performance, can obtain high catalytic activity and high propylene selectivity in the direct dehydrogenation reaction, is not easy to deposit carbon in the reaction process, and has simple and convenient preparation method and easily obtained raw materials.)

1. A nano-carbon supported cobalt nitrogen carbon catalytic material is characterized in that: the nano-carbon supported cobalt nitrogen carbon catalytic material is a composite structure formed by uniformly supporting a cobalt nitrogen carbon layer on the surface of a nano-carbon carrier, and the specific surface area of the catalytic material is 100-350 m²·g^-1。

2. The nanocarbon-supported cobalt nitrogen carbon catalytic material of claim 1, wherein: in the cobalt nitrogen carbon layer, cobalt element is coordinated with pyridine nitrogen atom in an atomic form and then distributed in the carbon layer on the surface of the nano carbon.

3. The nanocarbon-supported cobalt nitrogen carbon catalytic material of claim 1, wherein: the nano carbon is a carbon oxide nano tube, nano graphene oxide, nano onion carbon oxide or nano diamond oxide; in the nano-carbon supported cobalt nitrogen carbon catalytic material, the weight ratio of cobalt element to nano-carbon is 1: 100-3: 10.

4. The nanocarbon-supported cobalt nitrogen carbon catalytic material as claimed in claim 3, wherein: the surface of the carrier of the nano-carbon-loaded cobalt nitrogen carbon catalytic material is only provided with one cobalt nitrogen carbon species, and the atomic percentage of cobalt elements in the cobalt nitrogen carbon species is 0.2-1%.

5. The preparation method of the nanocarbon-supported cobalt nitrogen carbon catalytic material according to any one of claims 1 to 4, characterized in that: the method specifically comprises the following steps:

(A) treating the nano-carbon powder by sequentially adopting concentrated hydrochloric acid and concentrated nitric acid to obtain a nano-carbon carrier;

(B) the method comprises the steps of complexing a micromolecular metal cobalt salt precursor with organic ligand phenanthroline, and then in-situ impregnating on the surface of a nano carbon carrier;

(C) and after calcining and acid washing, obtaining the nano carbon supported cobalt nitrogen carbon catalytic material.

6. The preparation method of the nanocarbon-supported cobalt nitrogen carbon catalytic material as claimed in claim 5, wherein: the step (a) specifically includes the following steps (a1) to (a5):

(A1) weighing a certain amount of unprocessed nano carbon powder, putting the nano carbon powder into a 200-500 ml round-bottom flask, and adding concentrated hydrochloric acid in a certain proportion; putting the round-bottom flask into a 100W ultrasonic oscillator, performing ultrasonic treatment for 30 minutes to uniformly disperse the nanocarbon, and then putting the round-bottom flask on a magnetic stirrer to stir at room temperature for 12 hours to obtain hydrochloric acid dispersion liquid of the nanocarbon; the mass ratio of the nanocarbon to the concentrated hydrochloric acid in the dispersion liquid is 1: 50-1: 100;

(A2) pouring the hydrochloric acid dispersion liquid of the nanocarbon obtained in the step (A1) into a sand core funnel, and performing suction filtration and washing by using deionized water until the pH value of the filtrate is 7; then placing the nano carbon after suction filtration in an oven at 80 ℃ for overnight drying;

(A3) grinding the dried nano carbon, putting the ground nano carbon into a round-bottom flask, adding concentrated nitric acid, and performing ultrasonic dispersion for 30 minutes to obtain a nitric acid dispersion liquid of the nano carbon; the mass ratio of the nano carbon to the concentrated nitric acid in the nitric acid dispersion liquid of the nano carbon is 1: 50-1: 100;

(A4) placing the round-bottom flask which is subjected to ultrasonic treatment and is filled with the nitric acid dispersion liquid of the nano-carbon in an oil bath kettle at the temperature of 120 ℃, and refluxing for 2 hours at constant temperature;

(A5) and after the temperature is reduced to room temperature, pouring the materials in the refluxed round-bottom flask into a sand core funnel, performing suction filtration and washing by using deionized water until the pH value of the filtrate is 7, finally, putting the filtrate into an oven at 80 ℃ for overnight drying, and grinding to obtain the nano carbon carrier for later use.

7. The preparation method of the nanocarbon-supported cobalt nitrogen carbon catalytic material as claimed in claim 5, wherein: the step (B) specifically includes the following steps (B1) to (B7):

(B1) weighing 0.5-1 g of nano carbon carrier (oxidized nano carbon powder) and putting the nano carbon carrier into a 200ml round bottom flask, adding 80-100 ml of absolute ethyl alcohol as a solvent, and putting the mixture into a 100W ultrasonic oscillator for ultrasonic treatment for 30 minutes to uniformly disperse the nano carbon carrier (oxidized nano carbon powder);

(B2) weighing 5-200 mg of phenanthroline powder, dissolving in 30-40 ml of absolute ethanol, adding into the round-bottom flask obtained in the step (B1), and stirring at room temperature for 30 minutes to obtain a dispersion liquid;

(B3) weighing 5-150 mg of cobalt salt powder, and dissolving the cobalt salt powder in 40-60 ml of absolute ethyl alcohol to obtain a cobalt salt solution; adding the cobalt salt solution into a 60ml constant-pressure funnel, installing the funnel on a round-bottom flask, turning on a funnel switch to dropwise add the cobalt salt solution into the dispersion liquid obtained in the step (B2), and continuously stirring at room temperature for 10-12 hours after the cobalt salt solution is completely added;

(B4) after the stirring time is up, distilling off the solvent by utilizing a rotary evaporator under reduced pressure at 40 ℃ to obtain solid powder;

(B5) putting the solid powder obtained in the step (B4) into a tubular furnace, calcining for 2-4 hours at a constant temperature of 600 ℃ under the protection of argon, wherein the heating rate of the tubular furnace is 4.5 ℃/min, and the flow rate of argon is 40-50 ml/min;

(B6) after the temperature in the furnace is reduced to room temperature, taking out a sample, putting the sample into a 200ml beaker, adding 50-100 ml of 1mol/L hydrochloric acid solution, stirring and washing for 12 hours;

(B7) and (3) performing suction filtration and washing on the washed sample by using deionized water until the filtrate is colorless and the pH value is 7, and then putting the filtrate into an oven at 80 ℃ for drying to obtain the nano-carbon-loaded cobalt-nitrogen-carbon catalytic material.

8. The preparation method of the nanocarbon-supported cobalt nitrogen carbon catalytic material according to claim 7, wherein the preparation method comprises the following steps: in the step (B3), the cobalt salt is cobalt nitrate, cobalt sulfate, cobalt chloride or cobalt acetate; the molar ratio of the cobalt salt to the phenanthroline is 1: 2-1: 5.

9. The application of the nanocarbon-supported cobalt nitrogen carbon catalytic material as claimed in claim 1, wherein: the nano carbon supported cobalt nitrogen carbon catalytic material is used as a catalyst for the reaction of directly dehydrogenating propane to prepare propylene, and the propane is catalyzed to directly dehydrogenate to generate the propylene under the conditions of no oxygen, no water and normal pressure; the use temperature of the catalyst is 400-600 ℃.

10. The application of the nanocarbon-supported cobalt nitrogen carbon catalytic material as claimed in claim 1, wherein: in the direct propane dehydrogenation reaction process, the introduced mixed raw material gas is propane gas and inert gas (helium gas); the catalytic reaction conditions are as follows: airspeed of 1000-18000 ml g^-1h^-1And the partial pressure of the propane gas in the mixed raw material gas is 1-16 kpa.

Technical Field

The invention relates to the technical field of propane dehydrogenation reaction catalysts, in particular to a nano-carbon supported cobalt nitrogen carbon catalytic material and a preparation method and application thereof.

Background

Propylene is an important chemical raw material, and various petrochemical products such as polypropylene, propylene oxide, propionaldehyde, acrylonitrile and the like can be produced by using the propylene. The global propylene demand market has expanded over the last 20 years, with a considerable increase expected in the next few years, reaching a throughput of 1.65 million tons in 2030. The main source of propylene raw material is petroleum, but its reserves are reduced year by year and the price is continuously increased after a large amount of production, which causes the urgent need for development of new energy. With the advancement of modern hydraulic fracturing technology to enable large quantities of shale gas to be produced in a cost effective manner, it is estimated that 207 billion cubic meters of shale gas are technically producible worldwide, and these low cost chemical and fuel feedstocks will become new development trends. These undoubtedly will also bring about significant technical changes and economic opportunities for the industrial production of propylene. The main modes of traditional propylene production are catalytic cracking and steam cracking of petroleum, but the processes often cause the problems of high energy consumption, low propylene selectivity and the like, and the dehydrogenation technology can be used for producing target products in a targeted manner and improving the product purity. It is statistically estimated that the amount of propylene produced by the propane dehydrogenation process is about 500 million tons per year, and this figure is followed by a trend of continuous increase with the installation and expansion of several tens of new propane dehydrogenation facilities worldwide. These will bring great potential and prospect to the development of propane dehydrogenation catalysts, and therefore, it is significant and challenging to develop high-performance propane dehydrogenation propylene catalysts.

In order to meet the large-scale demand of propylene in global markets, the most mature preparation technology of the industry after transformation of the initial raw materials is prepared by the oxygen-free dehydrogenation reaction of propane, and the propylene yield which can be achieved at present is the highest. The most common commercial catalysts used in chemical enterprises are mainly two, one is PtSn/Al used in Oleflex technology₂O₃Catalyst, another is Cr/Al used in Catofin technology₂O₃A catalyst. Since the reaction is endothermic and is limited by thermodynamic equilibrium, the conversion rate of the reaction is increased by introducing conditions such as high temperature and low pressure under the catalysis of the catalyst. But the disadvantages are that the energy consumption is too high, the catalyst can generate carbon deposition inactivation at high temperature, the safety risk is high, and the like. Plus the price of platinum metalThe continuous rising and the toxicity problem of the chromium catalyst seriously restrict the further development of the technical process of the direct dehydrogenation of the propane. With the continuous increase of the demand of propylene in recent years, germanium, indium or manganese and other elements are also added into the traditional platinum-based catalyst as an auxiliary agent to form an alloy, so that the selectivity of the propylene and the stability of the catalyst are improved to a certain extent, but the problem of carbon deposition and inactivation of the catalyst at high temperature still exists. Therefore, the development of new high activity, low cost and environmentally friendly propane dehydrogenation catalysts remains an important catalytic challenge.

In recent years, many groups have studied dehydrogenation reactions of lower alkanes over non-noble metal catalysts, including metal oxide, metal sulfide, zeolite, and other types of catalysts. Among them, the cobalt-based catalyst, which is environmentally friendly, is receiving attention due to its good activation capability for carbon-hydrogen bonds and high selectivity for olefin products, but there are still controversies about the understanding of the nature of the active sites of dehydrogenation reactions, the valence state of cobalt species, and the interaction with the carrier. It is well known that the catalytic behavior of supported metal catalysts is closely related to the structure of surface species, such as particle size, shape, dispersion, and surface composition. Recently, non-noble metal catalysts containing nitrogen-carbon based (M-N-C) have been extensively developed for use in electrocatalytic oxygen reduction (ORR) and water cracking reactions, with activity and stability comparable to known Pt catalysts. On the basis of the redox activity of the catalyst, the M-N-C catalyst is further applied to organic reactions such as coupling, esterification and nitration and the like of carbon-hydrogen bond activation under a mild atmosphere, but the catalytic material is less researched in alkane dehydrogenation reaction under high-temperature thermal catalysis. And the metals in the M-N-C catalytic material are mainly in different coordination environments in an atomic-scale dispersion mode, so that the aggregation and growth of the metals can be prevented in the high-temperature pyrolysis preparation process, the utilization rate of the metal active sites is increased, and the characteristics of the environment-friendly catalyst are reflected. The nano carbon material has a complex surface structure and oxygen-containing functional groups on the surface, and has been used as a good non-metal material in the dehydrogenation reaction of low-carbon alkane in recent years, but the nano carbon material has more side reactions in oxidation conditions and has poor long-term stability of the reaction.

Disclosure of Invention

The invention provides a nano-carbon supported cobalt nitrogen carbon catalytic material and a preparation method and application thereof, aiming at solving the problems that noble metal-based and chromium-based catalysts in the prior art are expensive in price, easy to deposit carbon and inactivate when used for preparing propylene by direct propane dehydrogenation, toxic catalysts pollute the environment, and nano-carbon catalysts are low in activity and poor in long-term stability.

In order to achieve the purpose, the technical scheme of the invention is as follows:

a nano-carbon supported cobalt nitrogen carbon catalytic material is a composite structure formed by uniformly supporting an amorphous cobalt nitrogen carbon layer (active substance) on the surface of a nano-carbon carrier, and the specific surface area of the catalytic material is 100-350 m²·g^-1。

In the cobalt-nitrogen carbon layer, nitrogen mainly exists in the form of pyridine nitrogen, and the cobalt element and the pyridine nitrogen are distributed in the carbon layer on the surface of the nano carbon in a monodisperse form after being coordinated.

The nano carbon carrier is a carbon oxide nanotube, nano graphene oxide, nano onion carbon oxide or nano diamond oxide; in the nano-carbon supported cobalt nitrogen carbon catalytic material, the weight ratio of cobalt element to nano-carbon is 1: 100-3: 10.

The surface of the carrier of the nanocarbon supported cobalt nitrogen carbon catalytic material is only provided with one cobalt nitrogen carbon species, and the atomic percentage content of cobalt element in the cobalt nitrogen carbon species is 0.2-1% (preferably 0.19-0.6%).

The preparation method of the nano-carbon supported cobalt nitrogen carbon catalytic material comprises the following steps:

(A) treating the nano-carbon powder by sequentially adopting concentrated hydrochloric acid and concentrated nitric acid to obtain a nano-carbon carrier;

(B) the method comprises the steps of complexing a micromolecular metal cobalt salt precursor with organic ligand phenanthroline, and then in-situ impregnating on the surface of a nano carbon carrier;

(C) and after calcining and acid washing, obtaining the nano carbon supported cobalt nitrogen carbon catalytic material.

The step (a) specifically includes the following steps (a1) to (a5):

(A1) weighing a certain amount of unprocessed nano carbon powder, putting the nano carbon powder into a 200-500 ml round-bottom flask, and adding concentrated hydrochloric acid in a certain proportion; putting the round-bottom flask into a 100W ultrasonic oscillator, performing ultrasonic treatment for 30 minutes to uniformly disperse the nanocarbon, and then putting the round-bottom flask on a magnetic stirrer to stir at room temperature for 12 hours to obtain hydrochloric acid dispersion liquid of the nanocarbon; the mass ratio of the nanocarbon to the concentrated hydrochloric acid in the dispersion liquid is 1: 50-1: 100;

(A2) pouring the hydrochloric acid dispersion liquid of the nanocarbon obtained in the step (A1) into a sand core funnel, and performing suction filtration and washing by using deionized water until the pH value of the filtrate is 7; then placing the nano carbon after suction filtration in an oven at 80 ℃ for overnight drying;

(A3) grinding the dried nano carbon, putting the ground nano carbon into a round-bottom flask, adding concentrated nitric acid, and performing ultrasonic dispersion for 30 minutes to obtain a nitric acid dispersion liquid of the nano carbon; the mass ratio of the nano carbon to the concentrated nitric acid in the nitric acid dispersion liquid of the nano carbon is 1: 50-1: 100;

(A4) placing the round-bottom flask which is subjected to ultrasonic treatment and is filled with the nitric acid dispersion liquid of the nano-carbon in an oil bath kettle at the temperature of 120 ℃, and refluxing for 2 hours at constant temperature;

(A5) and after the temperature is reduced to room temperature, pouring the materials in the refluxed round-bottom flask into a sand core funnel, performing suction filtration and washing by using deionized water until the pH value of the filtrate is 7, finally, putting the filtrate into an oven at 80 ℃ for overnight drying, and grinding to obtain the nano carbon carrier for later use.

The step (B) specifically includes the following steps (B1) to (B7):

(B1) weighing 0.5-1 g of nano carbon carrier (oxidized nano carbon powder) and putting the nano carbon carrier into a 200ml round bottom flask, adding 80-100 ml of absolute ethyl alcohol as a solvent, and putting the mixture into a 100W ultrasonic oscillator for ultrasonic treatment for 30 minutes to uniformly disperse the nano carbon carrier (oxidized nano carbon powder);

(B2) weighing 5-200 mg of phenanthroline powder, dissolving in 30-40 ml of absolute ethanol, adding into the round-bottom flask obtained in the step (B1), and stirring at room temperature for 30 minutes to obtain a dispersion liquid;

(B3) weighing 5-150 mg of cobalt salt powder, and dissolving the cobalt salt powder in 40-60 ml of absolute ethyl alcohol to obtain a cobalt salt solution; adding the cobalt salt solution into a 60ml constant-pressure funnel, installing the funnel on a round-bottom flask, turning on a funnel switch to dropwise add the cobalt salt solution into the dispersion liquid obtained in the step (B2), and continuously stirring at room temperature for 10-12 hours after the cobalt salt solution is completely added;

(B4) after the stirring time is up, distilling off the solvent by utilizing a rotary evaporator under reduced pressure at 40 ℃ to obtain solid powder;

(B5) putting the solid powder obtained in the step (B4) into a tubular furnace, calcining for 2-4 hours at a constant temperature of 600 ℃ under the protection of argon, wherein the heating rate of the tubular furnace is 4.5 ℃/min, and the flow rate of argon is 40-50 ml/min;

(B6) after the temperature in the furnace is reduced to room temperature, taking out a sample, putting the sample into a 200ml beaker, adding 50-100 ml of 1mol/L hydrochloric acid solution, stirring and washing for 12 hours;

(B7) and (3) performing suction filtration and washing on the washed sample by using deionized water until the filtrate is colorless and the pH value is 7, and then putting the filtrate into an oven at 80 ℃ for drying to obtain the nano-carbon-loaded cobalt-nitrogen-carbon catalytic material.

In the step (B3), the cobalt salt is cobalt nitrate, cobalt sulfate, cobalt chloride or cobalt acetate; the molar ratio of the cobalt salt to the phenanthroline is 1: 2-1: 5.

The nano carbon supported cobalt nitrogen carbon catalytic material is used as a catalyst for the reaction of directly dehydrogenating propane to prepare propylene, and the propane is catalyzed to directly dehydrogenate to generate the propylene under the conditions of no oxygen, no water and normal pressure; the use temperature of the catalyst is 400-600 ℃.

In the direct propane dehydrogenation reaction process, the introduced mixed raw material gas is propane gas and inert gas (helium gas); the catalytic reaction conditions are as follows: airspeed of 1000-18000 ml g^-1h^-1And the partial pressure of the propane gas in the mixed raw material gas is 1-16 kpa.

In the propane dehydrogenation reaction, the conversion rate of propane is 2-25%, the selectivity of propylene is 90-97%, and the stability of the catalyst can reach more than 20 hours at the reaction temperature of 570 ℃.

The characteristics and advantages of the invention are as follows:

1. after the cobalt nitrogen carbon species are loaded on the surface of the nano carbon, the prepared composite catalyst not only keeps the activation performance of the cobalt nitrogen carbon species on carbon-hydrogen bonds in the propane dehydrogenation reaction, but also can exert the advantages of stable structure, large specific surface area and carbon deposition resistance of the nano carbon. More importantly, the catalytic performance advantage of the nano-carbon supported cobalt nitrogen carbon catalytic material in the propane dehydrogenation reaction is far greater than that of the simple physical mixture of the two substances. The composite catalyst is used as a non-noble metal catalyst capable of catalyzing propane dehydrogenation reaction, has good thermal stability and anti-carbon deposition capability, can catalyze propane to directly dehydrogenate to generate propylene under anhydrous, anaerobic and normal pressure conditions, and obtains high propylene yield.

2. Because of its good redox activity, cobalt nitrogen carbon catalytic materials are used in large quantities in electrocatalytic oxygen reduction reactions, while few studies have been made in thermally catalyzed alkane dehydrogenation reactions. The nano-carbon supported cobalt nitrogen carbon catalytic material prepared by the invention is firstly used for catalyzing the reaction of propane dehydrogenation to prepare propylene.

3. In the nano-carbon supported cobalt nitrogen carbon catalyst, the cobalt nitrogen carbon active species are single and can be uniformly dispersed on the surface of the nano-carbon in a monodispersed form, and strong interaction exists between the cobalt nitrogen carbon active species and the nano-carbon, so that the composite catalyst has good structural stability and chemical activity, and the utilization rate of metal active sites in the catalyst is maximized.

4. In the reaction of preparing propylene by catalyzing propane direct dehydrogenation under the condition of anhydrous, oxygen-free and normal pressure by adopting the nano carbon loaded cobalt nitrogen carbon material, the conversion rate of propane is 2-25%, the selectivity of propylene is 90-97%, and the long-term reaction stability is more than 20 hours.

5. Compared with the traditional platinum-based and chromium-based catalysts, the nano-carbon loaded cobalt-nitrogen-carbon material adopted by the invention has the advantages that the preparation method is simpler, the raw materials are low in price and easy to obtain, the development concept of the environment-friendly catalyst is reflected, and the nano-carbon loaded cobalt-nitrogen-carbon material has higher catalytic activity, stability and propylene selectivity compared with the traditional nano-carbon catalyst.

Drawings

Fig. 1 is a schematic diagram of a simple preparation of a carbon nanotube-supported cobalt-nitrogen-carbon oxide catalytic material.

Fig. 2 is a surface morphology and a component characterization of the oxidized carbon nanotube-supported cobalt nitrogen carbon catalytic material in example 1. Wherein: FIG. A is a dark-field transmission electron micrograph of a carbon nanotube oxide loaded with a cobalt nitrogen carbon catalytic material; and (B), (C) and (D) are scanning electron microscope element spectrograms of the carbon-carbon catalytic material with cobalt nitrogen loaded on the carbon oxide nanotubes, wherein the elements are respectively represented by nitrogen (N), carbon (C) and cobalt (Co).

Fig. 3 is a comparison graph of Co2p X-ray photoelectron spectroscopy (XPS) of carbon nanotube oxide loaded with different contents of cobalt nitrogen carbon catalytic material.

Fig. 4 is a comparison graph of N1s X-ray photoelectron spectroscopy (XPS) of carbon nanotubes loaded with different contents of cobalt nitrogen carbon catalytic material.

Fig. 5 is a thermogravimetric graph of carbon nanotubes oxidized loaded with different contents of cobalt nitrogen carbon catalytic material in air.

Fig. 6 is a comparison graph of the activities of the carbon nanotube oxide loaded with different contents of cobalt nitrogen carbon catalytic material and the reference material in the propane dehydrogenation reaction.

Detailed Description

The present invention will be described in detail with reference to examples.

The nanocarbon supported cobalt nitrogen carbon catalytic materials used in the following examples are all self-synthesized materials, and are black powder.

The preparation process of the oxidized carbon nanotube support in the following examples is as follows:

(A1) weighing untreated carbon nanotube powder, putting the powder into a round-bottom flask of 200-500 ml, and adding concentrated hydrochloric acid according to the mass ratio of the carbon nanotube to the concentrated hydrochloric acid of 1: 50-1: 100; putting the round-bottom flask into a 100W ultrasonic oscillator, performing ultrasonic treatment for 30 minutes to uniformly disperse the nano carbon, and then putting the round-bottom flask on a magnetic stirrer to stir at room temperature for 12 hours to obtain hydrochloric acid dispersion liquid of the carbon nano tube;

(A2) pouring the dispersion liquid obtained in the step (A1) into a sand core funnel, and performing suction filtration and washing by using deionized water until the pH value of the filtrate is 7; then placing the carbon nano tube after suction filtration in an oven at 80 ℃ for overnight drying;

(A3) grinding the dried carbon nano tube, putting the carbon nano tube into a round-bottom flask, adding concentrated nitric acid according to the mass ratio of the carbon nano tube to the concentrated nitric acid of 1: 50-1: 100, and performing ultrasonic dispersion for 30 minutes to obtain a nitric acid dispersion liquid of the carbon nano tube;

(A4) placing the round-bottom flask which is subjected to the ultrasonic treatment in the step (A3) and is filled with the dispersion liquid into an oil bath kettle at the temperature of 120 ℃, and refluxing for 2 hours at constant temperature; and after the temperature is reduced to room temperature, pouring the materials in the refluxed round-bottom flask into a sand core funnel, performing suction filtration and washing by using deionized water until the pH value of the filtrate is 7, finally, putting the filtrate into an oven at 80 ℃ for overnight drying, and grinding to obtain carbon oxide nanotube powder serving as a nano carbon carrier for later use.