阅读说明：本技术 一种多孔棒状Co/C纳米棒复合材料的制备方法 (Preparation method of porous rod-shaped Co/C nanorod composite material ) 是由 高鹏 邓苹 于 2021-07-13 设计创作，主要内容包括：本发明涉及催化剂技术领域,针对贵金属掺杂改性电催化剂成本高的问题,提供一种多孔棒状Co/C纳米棒复合材料的制备方法,包括以下步骤：利用NTA和Co(NO-(3))-(2)·6H-(2)O水热法制得前驱体,将前驱体煅烧,450-500℃下在惰性气体中煅烧2-2.5小时,煅烧完成后降温得棒状多孔Co/C纳米棒复合电催化剂。本发明由NTA与金属盐Co(NO-(3))-(2)·6H-(2)O先水热后管式炉烧结制得,条件温和、纯度好,且制得的棒状多孔Co/C纳米棒复合电催化剂,具有较高的电催化活性。(The invention relates to the technical field of catalysts, and provides a preparation method of a porous rod-shaped Co/C nanorod composite material aiming at the problem of high cost of a noble metal doped modified electrocatalyst, which comprises the following steps: using NTA and Co (NO) 3 ) 2 ·6H 2 Preparing a precursor by an O hydrothermal method, calcining the precursor in inert gas at the temperature of 450-500 ℃ for 2-2.5 hours, and cooling after the calcination is finished to obtain the rod-shaped porous Co/C nanorod composite electrocatalyst. The invention is composed of NTA and metal salt Co (NO) 3 ) 2 ·6H 2 The O is prepared by hydrothermal and then sintering in a tube furnace, the condition is mild, the purity is good, and the prepared rod-shaped porous Co/C nanorod composite electrocatalyst has higher electrocatalytic activity.)

1. A preparation method of a porous rod-shaped Co/C nanorod composite material is characterized by comprising the following steps: mixing NTA and Co (NO)₃)₂·6H₂And O, preparing a precursor by a hydrothermal method, calcining the precursor in an inert gas at the temperature of 450-500 ℃ for 2-2.5 hours, and cooling after the calcination is finished to obtain the rod-shaped porous Co/C nanorod composite electrocatalyst.

2. The method of claim 1, wherein NTA and Co (NO) are used as raw materials for preparing the porous rod-shaped Co/C nanorod composite material₃)₂·6H₂The molar ratio of O is (0.5-2) to 1.

3. The method for preparing a porous rod-like Co/C nanorod composite material according to claim 1 or 2, wherein the NTA and Co (NO) are₃)₂·6H₂The mixing process of O is as follows: dispersing NTA in water, adding Co (NO)₃)₂·6H₂And O, stirring to dissolve, adding isopropanol, and stirring uniformly.

4. The method for preparing the porous rod-like Co/C nanorod composite material according to claim 1, wherein the reaction conditions of the hydrothermal method are as follows: the reaction temperature is 160-200 ℃, and the reaction time is 4-8 h.

5. The method for preparing the porous rod-like Co/C nanorod composite material according to claim 1, wherein a reaction product obtained by a hydrothermal method is centrifuged to obtain a precipitate, and the precipitate is washed and dried to obtain the precursor.

6. The method for preparing a porous rod-like Co/C nanorod composite material according to claim 5, wherein the washing is: washing with water to neutral, and washing with anhydrous ethanol for 1-3 times.

7. The method for preparing a porous rod-like Co/C nanorod composite material according to claim 5 or 6, wherein the drying condition is that the drying is performed at 50-70 ℃ for 10-12 hours under vacuum.

8. The method for preparing the porous rod-like Co/C nanorod composite material according to claim 1, wherein the precursor calcination is performed in a tube furnace, and the temperature rise speed of the tube furnace is controlled to be 3-5 ℃/min.

Technical Field

The invention relates to the technical field of catalysts, in particular to a preparation method of a porous rod-shaped Co/C nanorod composite material.

Background

In recent years, the problems of environmental pollution and energy shortage have become increasingly serious, and research and development of various novel energy techniques and equipment have been intensively conducted. The electrocatalysis technology has the advantages of environmental friendliness, high chemical energy and the like, and is widely considered as an important way for solving the problems of environmental pollution and energy crisis. With the development of industrialization, the problems of energy shortage and environmental pollution become more serious, which forces people to continuously search clean and sustainable energy to improve the environmental and energy problems. Ammonia is one of the essential raw materials for industrial development and agriculture. On the other hand, with the rapid development of industry, a large amount of nitrate flows into the environment, pollutes underground water, threatens the health of people, destroys natural nitrogen circulation, and the electrocatalytic synthesis of ammonia from nitrate is one of important ways with good development prospect and application prospect at present, and can provide a good scheme for solving two problems of energy and environment. The device can greatly realize the conversion of electric energy into chemical energy, and meanwhile, the electric energy can be converted from various channels such as wind energy, solar energy, tidal energy and the like, and the device also has the characteristics of environmental friendliness, high stability and the like. Co is currently one of the elements that are of great interest and promising for the fabrication of electrocatalysts. The catalyst has the advantages of high electrocatalysis performance, high oxidation efficiency, no toxicity, low cost, easy obtainment, environmental protection and the like, so that the catalyst is widely applied to the aspects of photoelectric conversion, hydrogen production by decomposing water to produce oxygen, pollutant degradation and the like.

However, the conventional metal electrocatalyst has a significant side reaction during the reaction. The electrolyte has the defects of low stability, low electron transmission rate, unobtrusive adsorption performance and the like in the electrolyte, and the utilization efficiency of the electrolyte on electric energy is extremely low, so that the large-scale application of the electrolyte in the technical field of electrocatalysis is hindered; in addition, it is easily associated with severe hydrogen evolution side reactions and it is extremely susceptible to corrosion during the reaction, thus reducing its catalytic efficiency, which is a major drawback as an electrocatalyst. Therefore, in view of the above problems, a series of strategies are proposed to modify the above electrocatalyst, and for example, patent CN112058308B discloses an organic-inorganic composite formaldehyde catalytic composition, a preparation method thereof, and an air purification filter element, which comprise the following components in parts by weight: 10-50 parts of modified catalyst, 30-50 parts of modified bentonite and 40-100 parts of high molecular organic polymer. According to the invention, the precious metal-doped composite electrocatalyst is carried by the rare earth element modified carrier, and a microenvironment is formed on the surface of the catalyst by the rare earth metal solid ions, so that the inhibition of water vapor on the catalytic activity in the reaction process can be effectively avoided, and the synergistic effect between the two electrocatalysts and Pt can be enhanced, so that formaldehyde is completely catalytically converted into carbon dioxide and water at room temperature, the addition amount of precious metals is remarkably reduced, and the performance of the electrocatalysis oxidation of formaldehyde at room temperature is not reduced. The use of precious metals also raises costs. Besides noble metal loading modification, metal oxide doping modification, semiconductor composite modification, ion doping modification and the like exist, in the strategy methods, electrocatalysts can generate synergistic action with the noble metal loading modification, so that the electrocatalysis activity is well enhanced, however, the defects of uncontrollable content, destructive conjugated systems and the like limit the application of the electrocatalysis. Therefore, there is a need to find suitable electrocatalysts to improve their electrocatalytic performance.

Disclosure of Invention

The invention provides a preparation method of a porous rod-shaped Co/C nanorod composite material, aiming at overcoming the problem of high cost of a noble metal doped modified electrocatalyst, and the preparation method is prepared from NTA and metal salt Co (NO)₃)₂·6H₂The O is prepared by firstly hydrothermal and then sintering in a tube furnace, the condition is mild, the purity is good, the method is suitable for large-scale manufacture, and the prepared rod-shaped porous Co/C nanorod composite electrocatalyst has higher electrocatalytic activity.

In order to achieve the purpose, the invention adopts the following technical scheme:

a preparation method of a porous rod-shaped Co/C nanorod composite material comprises the following steps: mixing NTA (nitrilotriacetic acid) and Co (NO)₃)₂·6H₂And O, preparing a precursor by a hydrothermal method, calcining the precursor in an inert gas at the temperature of 450-500 ℃ for 2-2.5 hours, and cooling after the calcination is finished to obtain the rod-shaped porous Co/C nanorod composite electrocatalyst.

The rod-shaped porous Co/C nanorod composite electrocatalyst prepared by the synthesis method provided by the invention has high electrocatalytic activity, has a high specific area due to a unique porous loose structure, has a high-density catalytic activity center, increases the specific surface area of the catalyst due to the porous structure, and enhances the conductivity and the stability of the material due to the carbon layer. The utilization rate and the absorptivity of energy are improved, and the utilization efficiency of visible light is obviously improved. The synthesis method provided by the invention has the characteristics of mild conditions, good purity and the like, and is suitable for industrial large-scale production and application.

Preferably, NTA and Co (NO)₃)₂·6H₂The molar ratio of O is (0.5-2) to 1.

Preferably, the NTA and Co (NO)₃)₂·6H₂The process of O mixing is as follows: dispersing NTA in water, adding Co (NO)₃)₂·6H₂And O, stirring to dissolve, adding isopropanol, and stirring uniformly.

Preferably, the reaction conditions of the hydrothermal method are as follows: the reaction temperature is 160 ℃ and 200 ℃, and the reaction time is 4-8 h.

Preferably, the reaction product obtained by the hydrothermal method is firstly centrifuged to obtain precipitate, and the precipitate is washed and dried to obtain the precursor.

Preferably, the washing is: washing with water to neutral, and washing with anhydrous ethanol for 1-3 times.

Preferably, the drying is carried out under vacuum at 50-70 deg.C for 10-12 hr.

Preferably, the precursor calcination is carried out in a tube furnace, and the temperature rise rate of the tube furnace is controlled to be 3-5 ℃/min.

Therefore, the beneficial effects of the invention are as follows: the porous rod-shaped Co/C composite electrocatalyst prepared by the invention is a novel functional material with good adsorption and desorption performance and excellent electrocatalysis performance, compared with the traditional electrocatalyst, the porous material has a high specific area and a high-density catalytic activity center, the specific surface area of the material is increased by the porous structure, the stability and the conductivity of the material are enhanced, and the reaction catalysis efficiency is improved.

Drawings

FIG. 1 is an XRD pattern of a rod-shaped porous Co/C nanorod composite electrocatalyst prepared in examples 1-3 of the present invention.

FIG. 2 is a scanning electron microscope microscopic morphology view of the rod-shaped porous Co/C nanorod composite electrocatalyst prepared in example 1 of the present invention.

FIG. 3 is a transmission electron microscope microscopic morphology view of the rod-shaped porous Co/C nanorod composite electrocatalyst prepared in example 1 of the present invention.

Detailed Description

The technical solution of the present invention is further illustrated by the following specific examples.

In the present invention, unless otherwise specified, all the raw materials and equipment used are commercially available or commonly used in the art, and the methods in the examples are conventional in the art unless otherwise specified.

Example 1

A preparation method of a porous rod-shaped Co/C nanorod composite material comprises the following steps:

(1) preparing a precursor: in a beaker containing 10mL of deionized water, 0.1911g of NTA white powder was added and dispersed, and 0.20g of Co (NO) was added₃)₂·6H₂O, NTA and Co (NO)₃)₂·6H₂The molar ratio of O is 1:1, the mixture is magnetically stirred for 10 minutes at normal temperature until the mixture is completely dissolved, then 20ml of isopropanol is added, the mixture is magnetically stirred for half an hour at normal temperature until the mixture is uniform, the mixture is moved into a high-pressure reaction kettle, and the mixture is put into an oven to react for 6 hours at 180 ℃; and centrifuging the reaction product by using a high-speed centrifuge at the rotating speed of 4000rpm to obtain a precipitate, washing the precipitate for 3 times to be neutral, then washing the precipitate for 3 times by using absolute ethyl alcohol, and drying the washed precipitate in a vacuum oven at the temperature of 60 ℃ for 12 hours to obtain a precursor.

(2) Preparing a Co/C nano rod: calcining the precursor by using a tube furnace, controlling the heating rate to be 5 ℃/min, heating for 90 minutes to 450 ℃, calcining for 2 hours in argon, and naturally cooling to obtain the final product, namely the rod-shaped porous Co/C nanorod composite electrocatalyst.

The micro-morphology of the prepared porous rod-shaped Co/C nanorod composite electrocatalyst is observed, and the structure diagrams shown in figures 2 and 3 are obtained. As can be seen from FIG. 2, it has a good and stable micro-morphology, wherein the size of the rod-like Co/C nanorods is uniform and the bonding is good; as can be seen from FIG. 3, it has a good micro-morphology, uniform distribution and obvious porosity.

Example 2

A preparation method of a porous rod-shaped Co/C nanorod composite material comprises the following steps:

(1) preparing a precursor: in a beaker containing 10mL of deionized water, 0.0994g of NTA white powder was added and dispersed, and 0.21g of Co (NO) was added₃)₂·6H₂O, NTA and Co (NO)₃)₂·6H₂The molar ratio of O is 1:2, the mixture is magnetically stirred for 10 minutes at normal temperature until the mixture is completely dissolved, then 20ml of isopropanol is added, the mixture is magnetically stirred for half an hour at normal temperature until the mixture is uniform, the mixture is moved into a high-pressure reaction kettle, and the mixture is put into an oven to react for 6 hours at 180 ℃; centrifuging the reaction product by a high-speed centrifuge at the rotating speed of 4000rpm to obtain precipitate, and washing the precipitate with waterWashing with anhydrous ethanol for 3 times after 3 times to neutrality, and drying the washed precipitate in a vacuum oven at 60 deg.C for 12 hr to obtain precursor;

(2) preparing a Co/C nano rod: calcining the precursor by using a tube furnace, controlling the heating rate to be 5 ℃/min, heating for 90 minutes to 450 ℃, calcining for 2 hours in argon, and naturally cooling to obtain the final product, namely the rod-shaped porous Co/C nanorod composite electrocatalyst.

Example 3

A preparation method of a porous rod-shaped Co/C nanorod composite material comprises the following steps:

(1) preparing a precursor: 0.38g NTA white powder was added to a beaker containing 10mL deionized water and dispersed, followed by 0.20g Co (NO)₃)₂·6H₂O, NTA and Co (NO)₃)₂·6H₂The molar ratio of O is 2:1, the mixture is magnetically stirred for 10 minutes at normal temperature until the mixture is completely dissolved, then 20ml of isopropanol is added, the mixture is magnetically stirred for half an hour at normal temperature until the mixture is uniform, the mixture is moved into a high-pressure reaction kettle, and the mixture is put into an oven to react for 6 hours at 180 ℃; centrifuging the reaction product by using a high-speed centrifuge at the rotating speed of 4000rpm to obtain a precipitate, washing the precipitate for 3 times to be neutral, then washing the precipitate for 3 times by using absolute ethyl alcohol, and drying the washed precipitate in a vacuum oven at the temperature of 60 ℃ for 12 hours to obtain a precursor;

(2) preparing a Co/C nano rod: calcining the precursor by using a tube furnace, controlling the heating rate to be 5 ℃/min, heating for 90 minutes to 450 ℃, calcining for 2 hours in argon, and naturally cooling to obtain the final product, namely the rod-shaped porous Co/C nanorod composite electrocatalyst.

FIG. 1 is an XRD pattern of a rod-shaped porous Co/C nanorod composite electrocatalyst prepared in examples 1-3 of the present invention. As can be seen from FIG. 1, the porous rod-shaped Co/C nanorod composite electrocatalysis prepared by the method has good crystallinity, no other impurities are generated, and the purity is high.

Example 4

A preparation method of a porous rod-shaped Co/C nanorod composite material comprises the following steps:

(1) preparing a precursor: in 10mL deionized water beaker add 0.1911g NTA white powder first to disperse, then add 0.20g Co(NO₃)₂·6H₂O, magnetically stirring for 10 minutes at normal temperature until the solution is completely dissolved, then adding 20ml of isopropanol, magnetically stirring for half an hour at normal temperature until the solution is uniform, transferring the solution to a high-pressure reaction kettle, putting the reaction kettle into an oven, and reacting for 8 hours at 160 ℃; and centrifuging the reaction product by using a high-speed centrifuge at the rotating speed of 4000rpm to obtain a precipitate, washing the precipitate for 3 times to be neutral, then washing the precipitate for 1 time by using absolute ethyl alcohol, and drying the washed precipitate in a vacuum oven at the temperature of 50 ℃ for 12 hours to obtain a precursor.

(2) Preparing a Co/C nano rod: calcining the precursor by using a tube furnace, controlling the heating rate to be 3 ℃/min, heating to 450 ℃ after 150 minutes, calcining for 2.5 hours in argon, and naturally cooling to obtain the final product, namely the rod-shaped porous Co/C nanorod composite electrocatalyst.

Example 5

A preparation method of a porous rod-shaped Co/C nanorod composite material comprises the following steps:

(1) preparing a precursor: in a beaker containing 10mL of deionized water, 0.1911g of NTA white powder was added and dispersed, and 0.20g of Co (NO) was added₃)₂·6H₂O, magnetically stirring for 10 minutes at normal temperature until the solution is completely dissolved, then adding 20ml of isopropanol, magnetically stirring for half an hour at normal temperature until the solution is uniform, transferring the solution to a high-pressure reaction kettle, putting the reaction kettle into an oven, and reacting for 4 hours at 200 ℃; and centrifuging the reaction product by using a high-speed centrifuge at the rotating speed of 4000rpm to obtain a precipitate, washing the precipitate for 3 times to be neutral, then washing the precipitate for 2 times by using absolute ethyl alcohol, and drying the washed precipitate in a vacuum oven at 70 ℃ for 10 hours to obtain a precursor.

(2) Preparing a Co/C nano rod: calcining the precursor by using a tube furnace, controlling the heating rate to be 5 ℃/min, heating to 500 ℃ after 100 minutes, calcining for 2 hours in argon, and naturally cooling to obtain the final product, namely the rod-shaped porous Co/C nanorod composite electrocatalyst.

Example 6

The difference from example 1 is NTA and Co (NO)₃)₂·6H₂The molar ratio of O is 3: 1.

Example 7

The difference from example 1 is NTA and Co (NO)₃)₂·6H₂The molar ratio of O is 1: 3.

Comparative example 1

The difference from example 1 is that the calcination temperature of the precursor was 700 ℃.

Comparative example 2

The difference from example 1 is that the calcination temperature of the precursor was 400 ℃.

Performance testing

The rod-shaped porous Co/C nanorod composite electrocatalyst prepared in example 1 is used for electrocatalysis of nitrate radical reduction to ammonia, the dosage of the catalyst is 20ug, the voltage is-0.6V, the electrolyte solution is 0.1mol/L potassium nitrate solution and 40mL, and the trend of the yield of ammonium radical changing with time is shown in the following table, which indicates that the catalyst has excellent catalytic performance.

The same electrocatalytic reaction was carried out using the rod-shaped porous Co/C nanorod composite electrocatalysts prepared in examples 2-7 and comparative examples 1-2, and the catalytic performances were as shown in the following table.

From the catalytic effect, the catalytic performance of the catalyst prepared in the examples 1 to 7 is greatly improved compared with that of the traditional catalyst. Example 6 Co (NO) vs example 1₃)₂·6H₂The amount of O used is relatively small and the catalytic performance is deteriorated because Co element acts to increase the active sites, but it can be seen from example 7 that the catalytic performance does not change much as the amount of Co element is further increased, so NTA and Co (NO) are added₃)₂·6H₂The molar ratio of O is preferably (0.5-2): 1. It can be seen from comparative examples 1 and 2 that the calcination temperature also has an effect on the catalytic performance, and the catalytic performance of comparative example 1 is reduced compared to example 1, presumably because too high a temperature causes blocking, affecting the porous structure.

Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.