CN110586115B - High-rate carbon nanotube catalyst, carbon nanotube and preparation method thereof - Google Patents
High-rate carbon nanotube catalyst, carbon nanotube and preparation method thereof Download PDFInfo
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Abstract
The invention relates to the technical field of preparation of carbon nanotubes and catalysts thereof, in particular to a high-rate carbon nanotube catalyst, a carbon nanotube and a preparation method thereof. The high-rate carbon nanotube catalyst is prepared by mixing the following raw materials in parts by weight: 13.45-19.97 parts of lanthanum nitrate, 0.39-2.95 parts of cobalt nitrate, 24.5-36.4 parts of nickel nitrate, 0.7-11.6 parts of magnesium nitrate, 0.25-0.98 part of chromium nitrate and 40.7-45.6 parts of pore-forming agent. According to the invention, a metal catalyst is designed into a nano multi-metal alloy phase, in order to disperse metal nano particles and reduce the probability of the metal nano particles meeting and growing, a second-phase inert crystal particle chromium nitrate is introduced in the preparation process to inhibit the growth of metal salt crystals, the second-phase crystal particles are inserted between the crystal boundaries of the first-phase crystal particles like a nail, the migration and coalescence of the first crystal particles after reduction are limited, the content of metal impurities in the prepared carbon nano tube is low, and the multiplying power of the carbon nano tube generated by cracking the high-rate carbon nano tube catalyst is 12-15.
Description
Technical Field
The invention relates to the technical field of preparation of carbon nanotubes and catalysts thereof, in particular to a high-rate carbon nanotube catalyst, a carbon nanotube and a preparation method thereof.
Background
The carbon nano tube is used as a one-dimensional nano material, has light weight, perfect connection of a hexagonal structure and a plurality of abnormal mechanical, electrical and chemical properties. With the research of carbon nanotubes and nanomaterials, the wide application prospect is continuously shown in recent years. Since the carbon nanotube has a hollow structure, it can be used as a micro mold. The metal, oxide and other substances can be filled in the nano-sized conductive wire, so that the finest nano-sized conductive wire and the like can be prepared and used in future molecular electronic devices or nano-electronic devices. It can also be used to make carbon nanotube reinforced plastics, carbon nanotube reinforced ceramic composite material, metal matrix composite material, the finest test tube and the nano-scale capable of weighing single atomic mass.
The growth of the carbon nanotube is mainly that under the catalytic action of the metal catalyst, carbon atoms are rearranged to form a one-dimensional tubular structure. The catalyst is used as a carbon source decomposition active center and a graphite carbon deposition center, and plays an important role in the morphology and structure of a decomposition product. The catalyst is also a nucleation center for the growth of the carbon nano tube and energy transportation, and the selection, preparation and selection of the carrier of the catalyst also have great influence on the nucleation, density, separation, purification and the like of the carbon nano tube, so that the carbon nano tube has different shapes and structures and is an important influence factor in the preparation of the carbon nano tube.
The transition metals Fe, Co and Ni are the most common raw materials of the metal catalyst, the effect of the metal catalyst is related to the properties of metal particles, including graphitization of the metal particles, the size of the metal particles and the like all influence the deposition of carbon atoms in the carbon nano tubes, the continuous growth of the carbon nano tubes is driven by the diffusion of carbon through the metal catalyst particles, and the metal catalyst has deformation in the process and follows a gas-liquid-solid (VLS) mechanism. The metal catalyst forms metal agglomeration in the deformation process to grow up, which leads to the problems of inactivation of the metal catalyst, unstable quality of the generated carbon nano tube and the like. At present, almost all researches on carbon nanotube metal catalysts are focused on the preparation of large-diameter carbon nanotubes, but almost no research is done on how to inhibit the agglomeration and growth of metal catalyst nanocrystal particles in the processes of roasting, reducing and the like, and how to prepare the high-rate carbon nanotube metal catalyst.
For example, chinese patent publication No. CN103721750A entitled catalyst for large-diameter carbon nanotubes and method for preparing the same discloses a catalyst for preparing large-diameter carbon nanotubes, which is prepared from the following raw materials in percentage by weight: 5.6-47.8% of lanthanum nitrate, 2.3-39.5% of cobalt nitrate, 1.7-46.7% of ferric nitrate, 2.7-41.6% of calcium nitrate, 2.7-41.6% of citric acid and 2.7-41.6% of ethylenediamine tetraacetic acid. The patent mainly researches a preparation method of a catalyst of a large-diameter carbon nano tube, the large-diameter carbon nano tube is added into a battery anode, the performance of the catalyst is greatly improved compared with the traditional graphite and the small-diameter carbon nano tube, but the catalyst has small catalytic multiplying power, metal agglomeration is easy to occur in the preparation roasting and reducing processes, and the catalytic efficiency is low.
At present, the multiplying power of commercial large-diameter carbon nanotube catalysts is generally small, about 5-8 times, and because the catalysts are easy to generate metal agglomeration in the roasting and reduction processes, the multiplying power of the prepared carbon nanotubes is low, the prepared carbon nanotubes contain high catalyst components and high metal impurity content, so that the subsequent purification cost is high, and the production cost is high.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention provides a method for preparing a high-rate carbon nanotube catalyst and a carbon nanotube, and solves the technical problems that in the prior art, metal catalyst nanocrystal particles are easy to agglomerate and grow in the roasting, reducing and other processes, so that the rate of the carbon nanotube is low and the content of metal impurities is high.
The purpose of the invention is realized by the following technical scheme:
the invention relates to a high-rate carbon nanotube catalyst which is prepared by mixing a first-phase metal catalyst crystal particle salt, a second-phase metal catalyst crystal particle salt and a pore-forming agent;
the first-phase metal catalyst crystal particle salt is prepared by mixing the following raw materials in parts by weight: 13.45-19.97 parts of lanthanum nitrate, 0.39-2.95 parts of cobalt nitrate, 24.5-36.4 parts of nickel nitrate and 0.7-11.6 parts of magnesium nitrate;
the second-phase metal catalyst crystal particle salt is chromium nitrate, and the weight part of the chromium nitrate is 0.25-0.98;
the weight part of the pore-forming agent is 40.7-45.6.
The invention selects nitrate as the precursor of the catalyst, and has the advantages that: the nitrate is heated and decomposed to generate nitrogen dioxide and metal oxide, the temperature required by decomposition is low, the nitrogen dioxide can be decomposed generally at about 600 ℃, and the generated nitrogen dioxide has no side effect on the catalytic component and is convenient to be treated by alkaline solution. The nickel nitrate is a precursor of nickel (Ni) which is a first main active component of the catalyst, the cobalt nitrate is a precursor of lanthanum (Co) which is a second active component of the catalyst, the lanthanum nitrate is a precursor of lanthanum (La) which is a secondary active component of the catalyst, and the magnesium nitrate is used as a combustion improver.
Further preferably, the first phase metal catalyst crystal particle salt is prepared by mixing the following raw materials in parts by weight: 14-16 parts of lanthanum nitrate, 1-2.95 parts of cobalt nitrate, 25-36.4 parts of nickel nitrate and 5.2-11.6 parts of magnesium nitrate; the weight part of the chromium nitrate is 0.3-0.98; the weight part of the pore-forming agent is 43.7-45.6.
Further preferably, the first phase metal catalyst crystal particle salt is prepared by mixing the following raw materials in parts by weight: 15.97 parts of lanthanum nitrate, 1.43 parts of cobalt nitrate, 36.4 parts of nickel nitrate and 5.2 parts of magnesium nitrate; the weight part of the chromium nitrate is 0.3; the weight portion of the pore-forming agent is 43.7.
Further preferably, the first phase metal catalyst crystal particle salt is prepared by mixing the following raw materials in parts by weight: 14.2 parts of lanthanum nitrate, 2.95 parts of cobalt nitrate, 24.5 parts of nickel nitrate and 11.6 parts of magnesium nitrate; the weight part of the chromium nitrate is 0.98; the weight portion of the pore-forming agent is 45.6.
The pore-forming agent mainly plays a role in pore-forming and specific surface area increasing in the preparation process of the catalyst, and can be used as the pore-forming agent in the preparation process of the catalyst in the prior art. Further preferably, the pore-forming agent is a compound of citric acid, DL-tartaric acid and polylactic acid, and the mass ratio of the pore-forming agent is as follows: citric acid DL-tartaric acid polylactic acid 1:0.1: 0.1. The invention selects the compound of citric acid, DL-tartaric acid and polylactic acid as the composite pore-forming agent, and has the advantages that: the complexing effect is better, so that the pore diameter of the catalyst carrier formed after roasting is more uniform, and the specific surface area is larger.
The invention also provides a preparation method of the high-rate carbon nanotube catalyst, which comprises the following steps of:
a. weighing lanthanum nitrate, cobalt nitrate, nickel nitrate, magnesium nitrate, chromium nitrate and a pore-forming agent according to the weight parts for later use;
b. adding deionized water into a reaction kettle, wherein the adding amount of the deionized water is as follows: injecting lanthanum nitrate according to the mass ratio of 3.6:1, stirring at the stirring speed of 10-20 r/min, heating, controlling the stirring speed to be 80-90 r/min when the temperature of the reaction kettle reaches 30-35 ℃, then putting lanthanum nitrate into the reaction kettle at a constant speed within 10-15 min, putting nickel nitrate into the reaction kettle at a constant speed within 8-12 min, and finally putting cobalt nitrate, magnesium nitrate and chromium nitrate into the reaction kettle at a constant speed within 5 min;
the solvent is deionized water, the addition amount of the deionized water is based on lanthanum nitrate, and the deionized water and the lanthanum nitrate are added according to the mass ratio of 3.6:1, so that the method has the advantages that: the method is suitable for preparing the catalyst on various scales, namely, all catalyst precursors are ensured to be completely dissolved, the specified concentration can be quickly reached, and the production efficiency is improved;
in the invention, lanthanum nitrate is used as a precursor of a secondary active component (La) of the catalyst at a set temperature, a set rotating speed and a set time, and the catalyst precursor can be quickly dissolved when being put into the reactor at a low temperature for the first time; the batch feeding has the advantages that: nickel nitrate is used as a precursor of a first main active component (Ni) of the catalyst, and the nickel nitrate and lanthanum nitrate are uniformly mixed in the stirring process when the nickel nitrate is put into the lanthanum nitrate solution in a second batch; cobalt nitrate, chromium nitrate and magnesium nitrate are respectively used as a second active component (Co) of the catalyst and a precursor of a second phase metal (Cr), and the cobalt nitrate, the chromium nitrate and the magnesium nitrate are put into the catalyst in a third batch, so that the cobalt nitrate, the chromium nitrate and the magnesium nitrate can be quickly dissolved in a mixed solution of nickel nitrate and lanthanum nitrate and are uniformly mixed in the stirring process; the metal oxide produced after roasting can be uniformly mixed;
c. continuing stirring for 30min, after uniformly mixing the raw materials in the step b, putting the pore-forming agent into the reaction kettle at a constant speed within 10-15 min to obtain a catalyst precursor mixed solution;
d. raising the temperature of the reaction kettle to 95-100 ℃, continuously stirring at the speed of 80-90 r/min until the mass concentration of the catalyst precursor mixed solution in the reaction kettle reaches 1.25-1.3 g/L, reducing the temperature of the reaction kettle to 35-40 ℃, and controlling the stirring speed to be 10-20 r/min to obtain a carbon nano tube catalyst precursor solution;
e. and d, roasting the carbon nano tube catalyst precursor solution obtained in the step d at the temperature of 550-700 ℃ for 1.5-1.8 h, cooling to normal temperature, and crushing to obtain the high-rate carbon nano tube catalyst.
The feeding at a constant speed of the invention refers to that: in a specified time, specified raw materials are uniformly put into a reaction kettle so as to achieve the state that the raw materials are uniformly mixed and the shape, the pipe diameter and the length-diameter ratio of the prepared product are optimal.
The roasting concentration of the catalyst precursor mixed solution is 1.25g/L, and the method has the advantages that: the method can ensure that the qualified catalyst is obtained by the mixed liquid with the concentration under the conditions of the set roasting temperature and time, and can ensure that the concentration of the later mixed solution meets the requirement under the conditions of the set temperature and stirring of the mixed liquid in the roasting process of the mixed liquid gradually discharged from the reaction kettle in different industrialized large-scale production, thereby avoiding the phenomenon that the roasted catalyst with the excessively high concentration of the mixed liquid is unqualified. Further preferably, when the mass concentration of the mixed solution in the reaction kettle in the step d reaches 1.25g/L, the temperature of the reaction kettle is reduced to 35-40 ℃.
Further preferably, the pulverization in the step e is performed by one of a zirconium ball pulverizer and an impeller pulverizer.
The invention also provides a carbon nano tube which is prepared by the following method:
A. putting the carbon nano tube catalyst with large multiplying power into a tubular furnace, and introducing nitrogen to replace air in the furnace tube until the oxygen content in the tubular furnace is less than 1 wt%;
B. changing nitrogen into methane gas, continuously introducing the methane gas into the tubular furnace, heating the tubular furnace to 800 ℃, reacting for 2.5 hours, stopping heating and introducing the methane gas, and continuously cooling by introducing the nitrogen until the temperature of the tubular furnace is less than 100 ℃ to obtain the carbon nano tube;
the high-rate carbon nanotube catalyst is the high-rate carbon nanotube catalyst or the high-rate carbon nanotube catalyst prepared by the preparation method.
More preferably, the carbon nanotube has a magnification of 12 to 15 and an ash content of 6.91 to 7.09%.
The invention starts from the growth mechanism of the carbon nano tube, the effect of the metal catalyst is related to the property of the metal particles, the graphitization of the metal particles, the size of the metal particles and the like all influence the deposition of carbon atoms in the carbon nano tube, the continuous growth of the carbon nano tube is driven by the diffusion of carbon through the metal catalyst particles, and the metal catalyst has deformation in the process and follows the gas-liquid-solid mechanism. Metal agglomerates formed in the deformation process of the metal catalyst grow, so that metal catalyst particles are enlarged or inactivated, and the problems that the diameter and the length of the generated carbon nano tube are not uniform, the length and the diameter are small and the like are caused, and electron microscope images of the generated carbon nano tube are shown in fig. 3 and fig. 5.
Therefore, the metal catalyst is designed into a nano multi-metal alloy phase (Ni-La-Co), and metal nano particles are dispersed, so that the probability of the metal nano particles growing when meeting is reduced; meanwhile, second-phase inert crystal particles (Cr) are introduced in the preparation process to inhibit the growth of metal salt crystals, and the second-phase crystal particles (Cr) are inserted between the crystal boundaries of the first-phase crystal particles (Ni-La-Co) like a nail to play a role in fixing the first crystal particles (Ni-La-Co). The second crystal grains (Cr) maintain the original shape and position during reduction, thereby limiting the migration and coalescence of the first crystal grains (Ni-La-Co) after reduction. The carbon nano-tube generated by carbon atoms as crystal nucleus deposition has uniform length and tube diameter; the catalytic active metal is fixed and limited by the second phase metal (Cr), so that the catalytic active metal is not easy to agglomerate to form larger crystal nucleus to cause the catalyst to lose efficacy, and the carbon nanotube can continuously deposit and grow for a longer time to generate the carbon nanotube with large length-diameter ratio, as shown in fig. 2 and 4.
The invention has the beneficial effects that: in the invention, the metal catalyst is designed into a nano multi-metal alloy phase, in order to disperse metal nano particles and reduce the probability of the metal nano particles meeting and growing, a second-phase inert crystal particle chromium nitrate is introduced in the preparation process to inhibit the growth of metal salt crystals, and the second-phase crystal particles are inserted between the crystal boundaries of the first-phase crystal particles like a nail to play a role in fixing the first crystal particles; the second crystal particles still keep the original shape and position during reduction, so that migration and coalescence of the reduced first crystal particles are limited, and metal catalyst nano crystal particles are prevented from easily agglomerating and growing in the roasting, reduction and other processes.
Drawings
FIG. 1 is a schematic diagram of the principle of the high-rate carbon nanotube catalyst according to the present embodiment;
FIG. 2 is an electron micrograph of a carbon nanotube prepared in example 1;
FIG. 3 is an electron micrograph of a carbon nanotube prepared in comparative example 1;
FIG. 4 is an electron micrograph of a carbon nanotube prepared in example 2;
FIG. 5 is an electron micrograph of a carbon nanotube prepared in comparative example 2;
FIG. 6 is an electron microscope image of carbon nanotubes prepared by the large-diameter carbon nanotube catalyst in the experimental example.
Detailed Description
The present invention will be described in further detail with reference to specific embodiments, but it should not be construed that the scope of the present invention is limited to the following examples. Various substitutions and alterations can be made by those skilled in the art and by conventional means without departing from the spirit of the method of the invention described above.
Examples
A preparation method of a large-rate carbon nanotube catalyst comprises the following steps:
a. respectively weighing lanthanum nitrate, cobalt nitrate, nickel nitrate, magnesium nitrate, chromium nitrate and pore-forming agent according to the weight parts shown in Table 1, designing into an example 1, a comparative example 1, an example 2 and a comparative example 2, and weighing for later use;
the pore-forming agent is prepared by mixing citric acid, DL-tartaric acid and polylactic acid according to the mass ratio of 1:0.1: 0.1; the lanthanum nitrate is lanthanum nitrate hexahydrate with the purity of more than 99.9 percent, and the nickel nitrate is nickel nitrate nonahydrate with the purity of more than 99.5 percent; the magnesium nitrate is tetrahydrate magnesium nitrate, and the purity of the magnesium nitrate is more than 99.5 percent; the citric acid is anhydrous citric acid, and the purity is more than 99.5%; the chromium nitrate is chromium nitrate nonahydrate, the purity is 99.5 percent; the cobalt nitrate is hexahydrate, and the purity is 99.5%;
preparing a high-rate carbon nanotube catalyst according to the following steps:
b. adding 58mL of deionized water into a 100mL reaction kettle, stirring at a stirring speed of 10-20 r/min, heating, controlling the stirring speed to be 80-90 r/min when the temperature of the reaction kettle reaches 30-35 ℃, then putting the weighed lanthanum nitrate into the reaction kettle at a constant speed within 10-15 min, then putting nickel nitrate into the reaction kettle at a constant speed within 8-12 min, and finally putting cobalt nitrate, magnesium nitrate and chromium nitrate into the reaction kettle at a constant speed within 5 min;
c. continuing stirring for 20-40 min, after the raw materials in the step b are uniformly mixed, putting the pore-forming agent into the reaction kettle at a constant speed within 10-15 min to obtain a catalyst precursor mixed solution;
d. raising the temperature of the reaction kettle to 95-100 ℃, continuously stirring at the speed of 80-90 r/min until the mass concentration of the catalyst precursor mixed solution in the reaction kettle reaches 1.25g/L, reducing the temperature of the reaction kettle to 35-40 ℃, and controlling the stirring speed to be 10-20 r/min to obtain a carbon nano tube catalyst precursor solution;
e. and d, roasting the carbon nanotube catalyst precursor solution obtained in the step d at 550-700 ℃ for 1.5-1.8 h, cooling to normal temperature, and crushing by using a zirconium ball crusher to respectively obtain the high-rate carbon nanotube catalyst.
SEM tests were performed on the carbon nanotubes prepared by the large-rate carbon nanotube catalysts obtained in example 1, comparative example 1, example 2, and comparative example 2, respectively, and the test results are shown in fig. 2 to 5.
FIG. 2 is an electron microscope image of 5 ten thousand times of the carbon nanotube of example 1, from which it can be seen that the carbon nanotube has uniform tube diameter and length, and a large length-diameter ratio;
FIG. 3 is an electron microscope image of 5 ten thousand times of the carbon nanotube of comparative example 1, from which it can be seen that the carbon nanotube has non-uniform tube diameter and length and a smaller major diameter;
FIG. 4 is an electron microscope image of 5 ten thousand times of the carbon nanotube of example 2, from which it can be seen that the carbon nanotube has uniform tube diameter and length, and a large length-diameter ratio;
FIG. 5 is an electron microscope image of 5 ten thousand times of the carbon nanotube of comparative example 2, from which it can be seen that the carbon nanotube has non-uniform tube diameter and length and a small major axis.
TABLE 1 weight ratios of raw materials in examples and comparative examples
| Raw materials | Example 1 | Comparative example 1 | Example 2 | Comparative example 2 |
| Lanthanum nitrate (g) | 15.97 | 15.97 | 14.2 | 14.2 |
| Cobalt nitrate (g) | 1.43 | 1.45 | 2.95 | 2.95 |
| N Nickel nitrate (g) | 36.4 | 36.4 | 24.5 | 24.5 |
| Magnesium nitrate (g) | 5.2 | 5.2 | 11.6 | 11.6 |
| Chromium nitrate (g) | 0.3 | 0 | 0.98 | 0 |
| Citric acid (g) | 43.7 | 43.7 | 45.6 | 45.6 |
A carbon nanotube is prepared by the following method:
A. putting 10g of the high-rate carbon nanotube catalyst into a tubular furnace, and introducing nitrogen to replace air in the furnace tube until the oxygen content in the tubular furnace is less than 1 wt%;
B. and (2) changing nitrogen into methane gas, continuously introducing the methane gas into the tubular furnace, heating the tubular furnace to 800 ℃, reacting for 2.5 hours, stopping heating and introducing the methane gas, introducing the nitrogen gas, continuously cooling until the temperature of the tubular furnace is less than 100 ℃, and obtaining the carbon nano tube, taking out and weighing, and calculating the growth rate. The data obtained are shown in Table 2.
TABLE 2 example and comparative example high rate carbon nanotube catalyst dosage, carbon nanotube yield and catalyst growth rate
| Experimental group | Large multiplying factor carbon nano tube catalyst dosage (g) | Yield (g) of carbon nanotubes | Growth rate |
| Example 1 | 10 | 141.12 | 14.11 |
| Comparative example 1 | 10 | 75.07 | 7.51 |
| Example 2 | 10 | 144.71 | 14.47 |
| Comparative example 2 | 10 | 75.05 | 7.51 |
As can be seen from table 2: because the catalyst of the invention is added with the second-phase metal crystal grain Cr and becomes the second stabilizer of the catalyst metal by utilizing the pinning effect of the crystal grain boundary, the yield of the carbon nano tube made by the catalyst is 1.88-1.93 times that of the carbon nano tube made by the catalyst without adding the second-phase metal crystal grain Cr catalyst (the catalyst obtained by the comparative example 1 and the catalyst obtained by the comparative example 2, which is referred to as a common catalyst for short); the catalyst multiplying power of the invention is averagely 14.1, while the multiplying power of the common catalyst is averagely 7.5; the reaction principle of the technical scheme of the invention is shown in figure 1.
According to the data in Table 3, the carbon nanotubes were weighed with an electronic balance with a precision of one hundred thousand, respectively, and put into a muffle furnace, and the temperature was maintained at 900 ℃ for 4 hours, and then cooled and weighed, and the ash content results are shown in Table 3.
Table 3 ash testing of carbon nanotubes prepared in examples and comparative examples
| Experimental group | Crucible (g) | Crucible + carbon tube (before burning) (g) | Crucible + carbon tube (after firing) (g) | Ash (%) |
| Example 1 | 26.448 | 29.213 | 26.6664 | 7.09 |
| Comparative example 1 | 26.087 | 28.827 | 26.4516 | 13.31 |
| Example 2 | 27.086 | 29.698 | 27.2664 | 6.91 |
| Comparative example 2 | 26.967 | 29.705 | 27.3314 | 13.31 |
As can be seen from table 3, the ash content of the carbon nanotube in the catalysts of comparative example 1 and comparative example 2 is 13.31%, and the ash content of the carbon nanotube prepared by the high-rate carbon nanotube catalyst of the present invention is 7.09-6.91%, that is, the impurities of the carbon nanotube prepared by the high-rate carbon nanotube catalyst of the present invention are nearly 2 times lower than those of the carbon nanotube prepared by the conventional catalyst.
Examples of the experiments
In order to better prove that compared with the prior art (the Chinese patent with the publication number of CN103721750A and the name of a large-diameter carbon nanotube catalyst and the preparation method thereof, called a large-diameter carbon nanotube catalyst for short, and the catalyst components of lanthanum, cobalt and iron), the technical scheme of the invention has more excellent technical effects, and the applicant of the application also performs the following experiments:
the large-diameter carbon nanotube catalyst is prepared according to the preparation method disclosed in the Chinese invention patent with the publication number of CN103721750A, and SEM test is carried out on the large-diameter carbon nanotube catalyst, and the test result is shown in figure 6.
FIG. 6 is an electron microscope image of 5 ten thousand times of carbon nanotubes produced by the large-diameter carbon nanotube catalyst, from which it can be seen that the carbon nanotubes have non-uniform tube diameter and length, and a relatively small length-diameter ratio;
further, as can be seen by comparing fig. 3, 5 and 6: common to the three figures is: the pipe diameter and the length are both uneven, and the length-diameter ratio is smaller.
Through 5 ten thousand times electron microscopic image analysis of the produced carbon nano tube, iron, lanthanum and cobalt are catalytic metals, no second phase inert metal exists, the mechanism of the generated carbon nano tube is the same as that of the comparative example 1 and the comparative example 2, and therefore the characteristics of the carbon nano tube are also the same as those reflected by the electron microscopic image.
According to the dosage of table 4, the carbon nanotube catalyst with large tube diameter 10g is prepared into the carbon nanotube with large tube diameter (carbon source methane) according to the carbon nanotube preparation method disclosed by the invention, and the multiplying power of the carbon nanotube (10g) prepared in the embodiment 1 of the invention is compared; the large diameter carbon nanotubes were then tested for ash according to the ash test methods and requirements of the examples. The test results are shown in Table 4.
Table 4 amount of carbon nanotube catalyst, yield of carbon nanotube, growth rate of catalyst, and ash content of catalyst used in example 1 and experimental examples
| Experimental group | Amount of catalyst used (g) | Yield (g) of carbon nanotubes | Growth rate (%) | Ash (%) |
| Example 1 | 10 | 141.12 | 14.11 | 7.09 |
| Large diameter carbon nanotube catalyst | 10 | 68.13. | 6.813 | 14.68 |
As can be seen from Table 4, the carbon nanotube growth rate of the large-diameter catalyst is 6.813, and the carbon nanotube growth rate of the catalyst of the present invention is 14.11, i.e., the impurities of the carbon nanotubes prepared by the catalyst of the present invention are 2.07 times lower than the impurities of the carbon nanotubes of the large-diameter catalyst.
Claims (9)
1. The high-rate carbon nanotube catalyst is characterized by being prepared by mixing first-phase metal catalyst crystal particle salt, second-phase metal catalyst crystal particle salt and a pore-forming agent;
the first-phase metal catalyst crystal particle salt is prepared by mixing the following raw materials in parts by weight: 13.45-19.97 parts of lanthanum nitrate, 0.39-2.95 parts of cobalt nitrate, 24.5-36.4 parts of nickel nitrate and 0.7-11.6 parts of magnesium nitrate;
the second-phase metal catalyst crystal particle salt is chromium nitrate, and the weight part of the chromium nitrate is 0.25-0.98;
the weight part of the pore-forming agent is 40.7-45.6;
when the large-rate carbon nanotube catalyst is prepared, the method comprises the following steps:
a. weighing lanthanum nitrate, cobalt nitrate, nickel nitrate, magnesium nitrate, chromium nitrate and a pore-forming agent according to the weight parts for later use;
b. adding deionized water into a reaction kettle, stirring at a stirring speed of 10-20 r/min, heating, controlling the stirring speed to be 80-90 r/min when the temperature of the reaction kettle reaches 30-35 ℃, then putting lanthanum nitrate into the reaction kettle at a constant speed within 10-15 min, then putting nickel nitrate into the reaction kettle at a constant speed within 8-12 min, and finally putting cobalt nitrate, magnesium nitrate and chromium nitrate into the reaction kettle at a constant speed within 5 min;
c. continuing stirring for 30min, after the raw materials in the step b are uniformly mixed, putting the pore-forming agent into the reaction kettle at a constant speed within 10-15 min to obtain a catalyst precursor mixed solution;
d. raising the temperature of the reaction kettle to 95-100 ℃, continuously stirring at the speed of 80-90 r/min until the mass concentration of the catalyst precursor mixed solution in the reaction kettle reaches 1.25-1.3 g/L, reducing the temperature of the reaction kettle to 35-40 ℃, and controlling the stirring speed to be 10-20 r/min to obtain a carbon nano tube catalyst precursor solution;
e. and d, roasting the carbon nano tube catalyst precursor solution obtained in the step d at the temperature of 550-700 ℃ for 1.5-1.8 h, cooling to normal temperature, and crushing to obtain the high-rate carbon nano tube catalyst.
2. The high-rate carbon nanotube catalyst according to claim 1, wherein the first phase metal catalyst grain salt is prepared by mixing the following raw materials in parts by weight: 14-16 parts of lanthanum nitrate, 1-2.95 parts of cobalt nitrate, 25-36.4 parts of nickel nitrate and 5.2-11.6 parts of magnesium nitrate; the weight part of the chromium nitrate is 0.3-0.98; the weight part of the pore-forming agent is 43.7-45.6.
3. The high-rate carbon nanotube catalyst according to claim 2, wherein the first phase metal catalyst grain salt is prepared by mixing the following raw materials in parts by weight: 15.97 parts of lanthanum nitrate, 1.43 parts of cobalt nitrate, 36.4 parts of nickel nitrate and 5.2 parts of magnesium nitrate; the weight part of the chromium nitrate is 0.3; the weight portion of the pore-forming agent is 43.7.
4. The high-rate carbon nanotube catalyst according to claim 1, wherein the first phase metal catalyst grain salt is prepared by mixing the following raw materials in parts by weight: 14.2 parts of lanthanum nitrate, 2.95 parts of cobalt nitrate, 24.5 parts of nickel nitrate and 11.6 parts of magnesium nitrate; the weight part of the chromium nitrate is 0.98; the weight portion of the pore-forming agent is 45.6.
5. The carbon nanotube catalyst with large multiplying power as claimed in any one of claims 1 to 4, wherein the pore-forming agent is a composite of citric acid, DL-tartaric acid and polylactic acid; the mass ratio of the citric acid to the DL-tartaric acid to the polylactic acid is 1:0.1: 0.1.
6. The carbon nanotube catalyst with large multiplying power as claimed in claim 1, wherein in the step d, when the mass concentration of the mixed solution in the reaction kettle reaches 1.25g/L, the temperature of the reaction kettle is reduced to 35-40 ℃.
7. The high-rate carbon nanotube catalyst according to claim 1, wherein the pulverization in the step e is performed by one of a zirconium ball pulverizer and an impeller pulverizer.
8. A carbon nanotube is characterized by being prepared by the following method:
A. putting the carbon nano tube catalyst with large multiplying power into a tubular furnace, and introducing nitrogen to replace air in the furnace tube until the oxygen content in the tubular furnace is less than 1 wt%;
B. changing nitrogen into methane gas, continuously introducing the methane gas into the tubular furnace, heating the tubular furnace to 800 ℃, reacting for 2.5 hours, stopping heating and introducing the methane gas, and continuously cooling by introducing the nitrogen until the temperature of the tubular furnace is less than 100 ℃ to obtain the carbon nano tube;
the large-rate carbon nanotube catalyst is the large-rate carbon nanotube catalyst as defined in any one of claims 1 to 7.
9. The carbon nanotube according to claim 8, wherein the carbon nanotube has a ratio of 12 to 15 and an ash content of 6.91 to 7.09%.
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1951567A (en) * | 2005-10-18 | 2007-04-25 | 中国石油天然气股份有限公司 | A kaolin based compound molecule sieve and preparation method thereof |
| WO2008029927A1 (en) * | 2006-09-08 | 2008-03-13 | Nano Process Institute Co., Ltd. | Method for production of carbon nanotube |
| CN103721750A (en) * | 2014-01-09 | 2014-04-16 | 深圳市三顺中科新材料有限公司 | Catalyst for preparing long-pipe-diameter carbon nano tubes and preparation method of catalyst |
| CN105460917A (en) * | 2015-12-08 | 2016-04-06 | 武汉理工大学 | Nitrogen-doped carbon nanotube adopting hierarchical structure and preparation method |
| CN105964268A (en) * | 2016-05-17 | 2016-09-28 | 深圳市河科科技有限公司 | Metal catalyst preparation method and preparation method of carbon nanotube |
| CN106953079A (en) * | 2017-03-27 | 2017-07-14 | 华中科技大学 | A kind of multilevel hierarchy carbon nano tube/tin dioxide composite and preparation method thereof |
| CN107376924A (en) * | 2017-07-17 | 2017-11-24 | 河北科技大学 | A kind of preparation method of multi-stage porous perovskite catalyst |
| CN107970907A (en) * | 2016-10-21 | 2018-05-01 | 中国石油化工股份有限公司 | A kind of nano composite oxide catalyst and its preparation method and application |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7169329B2 (en) * | 2003-07-07 | 2007-01-30 | The Research Foundation Of State University Of New York | Carbon nanotube adducts and methods of making the same |
| CN104284861A (en) * | 2012-04-16 | 2015-01-14 | 赛尔斯通股份有限公司 | Methods for treating offgas containing carbon oxides |
-
2019
- 2019-09-29 CN CN201910939520.1A patent/CN110586115B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1951567A (en) * | 2005-10-18 | 2007-04-25 | 中国石油天然气股份有限公司 | A kaolin based compound molecule sieve and preparation method thereof |
| WO2008029927A1 (en) * | 2006-09-08 | 2008-03-13 | Nano Process Institute Co., Ltd. | Method for production of carbon nanotube |
| CN103721750A (en) * | 2014-01-09 | 2014-04-16 | 深圳市三顺中科新材料有限公司 | Catalyst for preparing long-pipe-diameter carbon nano tubes and preparation method of catalyst |
| CN105460917A (en) * | 2015-12-08 | 2016-04-06 | 武汉理工大学 | Nitrogen-doped carbon nanotube adopting hierarchical structure and preparation method |
| CN105964268A (en) * | 2016-05-17 | 2016-09-28 | 深圳市河科科技有限公司 | Metal catalyst preparation method and preparation method of carbon nanotube |
| CN107970907A (en) * | 2016-10-21 | 2018-05-01 | 中国石油化工股份有限公司 | A kind of nano composite oxide catalyst and its preparation method and application |
| CN106953079A (en) * | 2017-03-27 | 2017-07-14 | 华中科技大学 | A kind of multilevel hierarchy carbon nano tube/tin dioxide composite and preparation method thereof |
| CN107376924A (en) * | 2017-07-17 | 2017-11-24 | 河北科技大学 | A kind of preparation method of multi-stage porous perovskite catalyst |
Non-Patent Citations (1)
| Title |
|---|
| "惰性固体粒子对液固两相循环流化结晶的影响及成核速率模型的建立";李君等;《中国粉体技术》;20001230;第6卷;第260-266页 * |
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