RU2323876C1 - METHOD FOR MANUFACTURING METAL-CARBON NANOSTRUCTURES BY REACTING ORGANIC COMPOUNDS WITH SALTS OF d-METALS - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: d-metal salt: cobalt chloride or nickel chloride, cobalt or nickel chloride crystallohydrate or silver nitrate, is treated with at least one of the following organic compounds: polyvinyl alcohol (PVA), acetylacetone (АА) or polyethylenepolyamine (PEPA). At first, a mixture of АА and PEPA may be prepared, PVA and d-metal salt aqueous solutions may be added to the said mixture to obtain gel, which is then dried to glassy state and milled. The said organic compounds and d-metal salt are taken in molar ratio of (5-1): 1. Then they are stage-heated to 200-400°C.

EFFECT: invention provides for reduction in power consumption and production of metal-carbon nanostructures in the form of films and tubulens.

2 cl, 18 dwg, 24 ex

Description

The invention relates to the field of coordination chemistry, including the physical chemistry of nanostructures and colloidal systems, and consists in the fact that the preparation of metal-containing carbon nanostructures (films and tubulenes) is carried out by dehydration and subsequent oxidative dehydro-polycondensation of PVA, AA and PEPA cleavage in the presence of silver nitrate AgNO ₃ , or cobalt chlorides CoCl ₃ , nickel NiCl ₂ .

Known methods for producing nanostructures, including those containing metals, by pyrolysis of polymers in the presence of metals [1, Y.Saito // Carbon, 1995, v.33, Is.7, p.979], by pyrolysis of hydrocarbons on metal catalysts [2, CJ Lee, J. Park, Y. Hue, JYLee // Chem. Phys. Lett., 2001, v.343, p.33-38], mechanochemically followed by sintering [3, A.V. Syugaev. Corrosive behavior of finely dispersed iron-based systems obtained by grinding in organic media. - Diss. Cand. Chem. N., Izhevsk: Physical Technical Institute, Ural Branch of the Russian Academy of Sciences, 2005], by electrochemical methods [4, W.K. M. Terrones, J. P. Hare et al // Chem. Phys. Lett., 1996, v.262, p.161-166], sol-gel methods [5, Pat. 2225835, 2004].

Pyrolysis of polymers in the presence of metals [1] is an energy-intensive and difficult to regulate method, the implementation of which forms a mixture of carbon nanostructures, most of which do not contain metals. The use of hydrocarbon pyrolysis on metal catalysts [2] to obtain a nanoproduct is inefficient. The preparation of nanostructures containing metals (iron) from the ends using mechanochemical methods occurs at high energy costs [3]. The use of electrochemical methods to obtain metal-containing nanoproducts [4] is associated with high energy costs. Obtaining nanoproducts using sol-gel methods [5] is largely determined by the stability of sols and gels, which can significantly affect the reproducibility of the results.

Thus, the disadvantages of these methods include:

1. Low productivity [2, 4].

2. High-energy costs for heating the starting materials (600-1000 ° C) [1, 2, 4].

3. High-energy costs for long-term mechanical grinding of the starting materials [3].

4. The lack of reproducibility of the results, which significantly affects the quality of the nanoproduct [1-5].

All of the above factors lead to the high cost of nanoproducts.

The closest technical solution is a method for producing metal-containing carbon nanostructures by heating to 300 ° C a mixture of polyvinyl alcohol with copper chlorides (CuCl) or copper (CuCl ₂ ) [6, V.I. Kodolov, A.A. Didik, A.Yu. Volkov, E.G. Volkova. A method for producing metal-containing carbon nanostructures from an organic compound with the addition of inorganic salts // Patent No. 2221744, 2004; СВВ 31/02]. This method consists in preparing gel-like films by drying aqueous solutions of copper and PVA chlorides, followed by grinding and heating to 300 ° C. The resulting product is washed with hot water and solvents to remove the starting materials and intermediates.

This prototype has the following disadvantages: the proposed method does not allow to obtain multifunctional nanoproducts containing metals and metal-containing compounds, which may include silver, nickel, cobalt, as well as heteroatoms such as oxygen and nitrogen; it does not make it possible to regulate the production of nanoproducts of a required size and shape with a specific yield.

The objective of the invention is the production of metal-containing carbon nanostructures in the form of films (amorphous or crystalline), nanotubes or their clusters, spherical metal nanostructures in carbon shells containing O and N heteroatoms, in a temperature range of 100-400 ° C.

This problem is solved due to the fact that in the method for producing metal-containing carbon nanostructures by the interaction of organic substances and d-metal salts in the temperature range of 100-400 ° C, acetylacetone, polyethylene polyamine and their mixtures in polyvinyl alcohol are used as organic compounds, and as d- metals - silver, nickel, cobalt in molar ratios: a mixture of organic compounds to a metal salt - (5-1): 1. The reaction mixture is prepared by mixing liquid organic components with metal salts or aqueous solutions of salts in PVA, followed by drying to obtain gel-like films.

The technical result is an increase in the multifunctionality of the obtained nanostructures due to the introduction of new complexones and metals involved in coordination with the reaction mixtures, stepwise heating, it is possible to obtain nanofilms with metals or metal-containing compounds on their surface (200 ° C), nanofilms with tubulenes between them (300 ° C), tubulenes containing metals (400 ° C).

In order to determine the yield of the solid residue of the synthesis product, the ratio C + Me in the obtained product to the initial mixture is considered. For this, the obtained products are treated with HCl (to remove possibly remaining unreacted chlorides, obtained metal oxides and oxychlorides, PVA, PEPA, AA). The resulting solid product is poured 2n. HCl at a temperature of 20-25 ° C, a volume of 8-10 volumes of the product, incubated for 60-90 minutes, then washed with distilled water at a temperature of 20-25 ° C. After processing, the product is filtered off and dried in air at a temperature of 20-25 ° C for 24-48 hours. The yield of solid product in relation to the theoretical is 70-80%, depending on the nature of the components and the temperature of synthesis.

The structure and composition of the obtained carbonization nanoproducts are studied by transmission electron microscopy, electron microdiffraction, and X-ray photoelectron spectroscopy. A JEM-200CX transmission electron microscope with an accelerating voltage of 160 kV and an electron diffraction attachment was used. X-ray photoelectron spectroscopy studies are carried out on an X-ray magnetic spectrometer with AlK _α- line excitation when a 10 ^-3 Pa rarefaction is created in the chamber of the spectrometer. The resolution of the device is 1.2 eV, the accuracy of the position of the peaks is 0.1 eV.

According to the data of electron microscopy of the samples, electron microdiffraction, and X-ray photoelectron spectroscopy, the presence of the following structures in carbonization products was established:

1. Amorphous carbon nanofilms containing oxygen (531.5-532.0 eV) and nitrogen (399.8-400.2 eV);

2. Pieces of amorphous carbon nanofilms that began to fold;

3. Single hollow carbon nanotubes (tubulens),

4. Splices consisting of carbon nanotubes,

5. Nanocrystals of metals or their compounds (chlorides or oxides),

6. Nanowires of metals,

7. Single metal-containing carbon nanotubes (tubulens).

The invention is illustrated by graphic materials:

Figure 1 presents a nickel-containing carbon nanotube;

Figure 2 presents a set of nanotubes containing nickel surrounded by a nanofilm;

Figure 3 presents the image of a set of amorphous spherical nanostructures containing nickel in carbon shells;

Figure 4 presents giant tubulen with a set of small nanotubes inside and on the surface;

Figure 5 presents a set of amorphous tubular nanostructures with pieces of coiled nanofilms;

Figure 6 presents the growing tubulene from a carbon-silver-containing aggregate;

Figure 7 presents the intergrowths of crystalline nanotubes containing silver;

On Fig presents a polycrystalline film of Ni with a carbon layer;

Figure 9 shows a portion of a carbon film at the edges of which carbon nanotubes are observed.

Figure 10 presents amorphous carbon nanotubes.

11 shows an amorphous carbon film, a diffuse halo is seen in the microdiffraction pattern.

Figure 12 shows an amorphous film, but graphite particles are present in it - this can be seen in the structural photograph and in the microdiffraction pattern.

On Fig presents pieces of an amorphous film, on the surface of which are pieces of graphite.

On Fig presents the accumulation of grains of graphite.

15 shows carbon tubes, separate reflexes appear on the background of the rings, the empty middle of the tubes is visible (these tubes are already crystalline).

On Fig presents pieces of a single crystal film of Ni (OH) ₂ .

On Fig presents an amorphous carbon film with grains of graphite.

On Fig presents the accumulation of carbon tubes, the tubes themselves are amorphous, in the same area there are particles of graphite.

Example 1. The proposed method for producing metal-containing carbon nanostructures is implemented as follows: to obtain a mixture of NiCl ₂ and AA in a molar ratio of 1: 1, take solid crystalline hydrate NiCl ₂ · 2H ₂ O weighing 10 g and add it to AA to obtain a homogeneous mixture. This mixture is placed in a closed crucible and incubated for 24 hours at a temperature of 20-25 ° C, after which the crucible is placed in a muffle furnace and heated. Heating is stepwise: from 100 to 400 ° C, with an interval of 100 ° C. The shutter speed in each mode is 60 minutes. The resulting product - a powder of dark gray or dark gray-green color was washed with 2n. HCl at a temperature of 20-25 ° C, with a volume of 8-10 volumes of the product, kept for 60-90 minutes, then washed with distilled water at a temperature of 20-25 ° C. After processing, the nanoproduct was filtered off and dried in air at a temperature of 20-25 ° C for 48 hours. The yield of solid nanoproduct relative to theoretical is 70%. The nanoproduct is a carbon nickel-containing nanotubes (figure 1, 2).

Example 2. The method of producing metal-containing carbon nanostructures according to example 1, in which instead of solid crystalline hydrate NiCl ₂ · 2H ₂ About take 2N. a solution of NiCl ₂ , which is added to AA. After obtaining a homogeneous solution, it is kept for 3 hours at a temperature of 20-25 ° C, and then heated in an oven at a temperature of 70-75 ° C to obtain a solid nanoproduct (10-12 h). The result is similar to example 1 (figure 3, 4).

Example 3. The method of producing metal-containing carbon nanostructures according to example 1, where instead of solid crystalline hydrate NiCl ₂ · 2H ₂ O take solid crystalline hydrate CoCl ₂ · 2H ₂ O. The result is similar to examples 1 and 2.

Example 4. A method of obtaining a metal-containing carbon nanostructures according to example 2, in which instead of 2N. a solution of NiCl ₂ take 2N. CoCl ₂ solution. The result obtained is similar to the result in examples 1 and 2.

Example 5. The method of producing silver-containing carbon nanostructures according to example 1, in which instead of solid crystalline hydrate NiCl ₂ · 2H ₂ O take solid silver nitrate AgNO ₃ . The heating temperature ends at 300 ° C. An image of the obtained nanoproducts is presented in FIGS. 5-7.

Example 6. A method for producing silver-containing carbon nanostructures according to example 2, where instead of 2n. a solution of NiCl ₂ is taken 2n. AgNO solution). The heating temperature ends at 300 ° C. The result obtained is similar to the result in example 5.

Example 7. The proposed method for producing metal-containing carbon nanostructures is implemented as follows: to obtain a mixture of PVA, PEPA and NiCl ₂ in a molar ratio of 1: 1: 1, the organic part is prepared, and then the inorganic part is added. First, a mixture of organic substances is prepared: PVA (10% aqueous solution) and PEPA by mixing until a homogeneous solution of a pale yellow solution is obtained. To the resulting solution was added solid crystalline hydrate NiCl ₂ · 2H ₂ O weighing 10 g and stirred until a clear solution of dark blue color was obtained. The resulting solution is poured into glass Petri dishes with a layer of 10 mm and heated in an oven at a temperature of 60-65 ° C until a solid gel is obtained. In this case, the gelation process takes 60-70 minutes. Heating to a temperature of 75-80 ° C greatly reduces the gelation time (up to 10-15 minutes), but negatively affects the quality of the film (strong adhesion, brittleness). The resulting film is removed from the surface of the glass, crushed to a size of 2-5 mm and placed in a closed crucible. The crucible should be tightly closed enough to allow a minimum amount of air to pass through, but not so much as to release the gases produced by heating the gel. The cooked crucible is placed in a muffle furnace and heated. Heating is stepwise: from 100 to 200 ° C, with an interval of 100 ° C. The shutter speed in each mode is 60 minutes. The resulting product is a dark brown porous film. It is ground in a crucible until a powder is obtained. The powder is washed with 2n. HCl at a temperature of 20-25 ° C, with a volume of 8-10 volumes of product, aged 60-90 minutes, then washed with distilled water at a temperature of 20-25 ° C. Rinsing continues until the rinse solution is completely clear. After processing, the product is filtered and dried in air at a temperature of 20-25 ° C for 48 hours. The yield of solid product in relation to theoretical is 70%. The resulting nanoproduct is a carbon nanofilm with a polycrystalline Ni film (Fig. 8).

Example 8. A method of producing a metal-containing carbon nanostructures according to example 7, when the synthesis temperature is increased to 300 ° C. The yield of solid product in relation to theoretical is 74%. Carbon nanofilms were obtained at the edges of which carbon nanotubes filled with nickel were observed (Fig. 9).

Example 9. A method for producing metal-containing carbon nanostructures according to example 7, in which the synthesis temperature is increased to 400 ° C. The yield of solid product in relation to the theoretical is 79%. Amorphous carbon nanotubes filled with nickel were obtained (Fig. 10).

Example 10. The method of producing metal-containing carbon nanostructures according to example 7, where instead of solid crystalline hydrate NiCl ₂ 2H ₂ O is taken solid crystalline hydrate CoCl ₂ · 2H ₂ O. The result is similar to example 7, but the nanofilm on the surface has cobalt compounds.

Example 11. The method of producing metal-containing carbon nanostructures according to example 7, in which instead of solid crystalline hydrate NiCl ₂ · 2H ₂ O is taken solid crystalline hydrate CoCl ₂ · 2H ₂ O, and the synthesis temperature is increased to 300 ° C. The result obtained is similar to example 8 with the difference that the metal is cobalt.

Example 12. The method of producing metal-containing carbon nanostructures according to example 7, where instead of solid crystalline hydrate NiCl ₂ · 2H ₂ O is taken solid crystalline hydrate CoCl ₂ · 2H ₂ O, and the synthesis temperature is increased to 400 ° C. The result obtained is similar to example 9, but in cobalt in nanotubes.

Example 13. The method of producing metal-containing carbon nanostructures according to example 7, in which instead of a mixture of PVA, PEPA and NiCl ₂ in a molar ratio of 1: 1: 1 take a mixture of PVA, PEPA and NiCl ₂ in a molar ratio of 2: 2: 1. An amorphous carbon film was obtained, a diffuse diffuse halo is seen in the microdiffraction pattern (Fig. 11). On the surface of the nanofilm are nickel nanocrystals and nickel-containing compounds.

Example 14. The method of producing metal-containing carbon nanostructures according to example 7, where instead of a mixture of PVA, PEPA and NiCl ₂ in a molar ratio of 1: 1: 1, take a mixture of PVA, PEPA and NiCl ₂ in a molar ratio of 2: 2: 1, and the synthesis temperature is adjusted up to 300 ° C. An amorphous film was obtained, but graphite particles were present in it, in addition to nickel nanocrystals (Fig. 12).

Example 15. The method of producing nickel-containing carbon nanostructures according to example 7, in which instead of a mixture of PVA, PEPA and NiCl ₂ in a molar ratio of 1: 1: 1, take a mixture of PVA, PEPA and NiCl ₂ in a molar ratio of 2: 2: 1, and the synthesis temperature increase to 400 ° C. Carbon tubes have been obtained, separate reflexes appear on the background of the rings, the empty middle of the tubes is visible, the tubes are partially filled with nickel or nickel-containing compounds. These tubes are already crystalline (Fig. 15).

Example 16. The method of producing cobalt-containing carbon nanostructures according to example 7, where instead of a mixture of PVA, PEPA and NiCl ₂ in a molar ratio of 1: 1: 1 take a mixture of PVA, PEPA and CoCl ₂ in a molar ratio of 2: 2: 1. The result obtained is similar to example 13.

Example 17. The method of producing metal-containing carbon nanostructures according to example 7, in which instead of a mixture of PVA, PEPA and NiCl ₂ in a molar ratio of 1: 1: 1 take a mixture of PVA, PEPA and CoCl ₂ in a molar ratio of 2: 2: 1, and the temperature synthesis increase to 300 ° C. The result obtained is similar to example 14.

Example 18. The method of producing metal-containing carbon nanostructures according to example 7, where instead of a mixture of PVA, PEPA and NiCl ₂ in a molar ratio of 1: 1: 1, take a mixture of PVA, PEPA and CoCl ₂ in a molar ratio of 2: 2: 1, and the synthesis temperature is increased up to 400 ° C. The result obtained is similar to example 15.

Example 19. The method of producing metal-containing carbon nanostructures according to example 7, in which instead of a mixture of PVA, PEPA and NiCl ₂ in a molar ratio of 1: 1: 1 take a mixture of PVA, PEPA, AA and NiCl ₂ in a molar ratio of 2: 2: 1: 1 . A structure was obtained containing, along with an amorphous carbon film, graphite particles (Fig. 13).

Example 20. The method of producing metal-containing carbon nanostructures according to example 7, where instead of a mixture of PVA, PEPA and NiCl ₂ in a molar ratio of 1: 1: 1 take a mixture of PVA, PEPA, AA and NiCl ₂ in a molar ratio of 2: 2: 1: 1, and the synthesis temperature is increased to 300 ° C. Samples were obtained that contain an amorphous carbon film with graphite grains and single-crystal films of Ni (OH) ₂ (Figs. 14, 16, 17).

Example 21. The method for producing nickel-containing carbon nanostructures according to example 7, in which instead of a mixture of PVA, PEPA and NiCl ₂ in a molar ratio of 1: 1: 1 take a mixture of PVA, PEPA, AA and NiCl ₂ in a molar ratio of 2: 2: 1: 1 , and the synthesis temperature is increased to 400 ° C. A cluster of carbon tubes was obtained, the tubes themselves are amorphous, graphite particles are present in the same region (Fig. 18).

Example 22. The method of producing metal-containing carbon nanostructures according to example 7, in which instead of a mixture of PVA, PEPA and NiCl ₂ in a molar ratio of 1: 1: 1 take a mixture of PVA, PEPA, AA and CoCl ₂ in a molar ratio of 2: 2: 1: one. The result obtained is similar to example 19.

Example 23. The method of producing metal-containing carbon nanostructures according to example 7, in which instead of a mixture of PVA, PEPA and NiCl ₂ in a molar ratio of 1: 1: 1 take a mixture of PVA, PEPA, AA and CoCl ₂ in a molar ratio of 2: 2: 1: 1 and the synthesis temperature is increased to 300 ° C. The result obtained is similar to example 20.

Example 24. The method of producing cobalt-containing carbon nanostructures according to example 7, where instead of a mixture of PVA, PEPA and NiCl ₂ in a molar ratio of 1: 1: 1 take a mixture of PVA, PEPA, AA and CoCl ₂ in a molar ratio of 2: 2: 1: 1, and the synthesis temperature is increased to 400 ° C. The result obtained is similar to example 21, but the metal in this case is cobalt.

Using the proposed method for producing metal-containing carbon nanostructures provides, in comparison with existing methods, the following advantages:

1. Reducing energy costs by reducing the synthesis temperature to 200-400 ° C.

2. The possibility of varying the obtained carbon nanostructures depending on temperature: from nanofilms at 200 ° C to nanotubes at 400 ° C.

3. An increase in the nomenclature due to the introduction of metals (Ni, Co, Ag) and new polyethylene polyamine (PEPA) and acetylacetone (AA) complexones into the reaction mixtures, which form strong complexes with these metals, which expands the possibilities of using the obtained nanostructures as catalysts and sorbents.

4. The introduction of heteroatoms (O, N) into the structure of nanofilms and nanotubes, which enhances the multifunctionality of the obtained nanostructures.

Claims (2)

1. A method for producing metal-containing carbon nanostructures, comprising treating d-metal salts with an organic substance containing functional groups by heating, characterized in that at least one of the organic substances is used as an organic compound: acetylacetone, polyethylene polyamine and polyvinyl alcohol, and as salts of d-metals, cobalt or nickel chloride, crystalline cobalt or nickel chloride hydrate or silver nitrate, wherein said organic compounds and salt are taken in molar relative to eniyah (5-1): 1, and is heated by a stepwise mode to 200-400 ° C. 2. The method according to claim 1, characterized in that the mixtures are prepared by mixing liquid substances in a specific order: a mixture of acetylacetone and polyethylene polyamine is preliminarily prepared, and then aqueous solutions of polyvinyl alcohol and metal salts are added to the prepared mixture to obtain a gel, which is dried before heating glassy state and ground.

Images