CN104384525B - The dispersion of a kind of nickel or ferronickel metal nanometer line and assemble method - Google Patents

Abstract

The invention belongs to the field of nanometer materials, in particular to a method for dispersing and assembling nickel or nickel-iron metal nanowires. The technical solution of the present invention is to first prepare nickel or nickel-iron metal nanowires by hydrothermal reaction, and then place the nickel or nickel-iron metal nanowires in a hydrochloric acid solution with a pH value of 3 to 6 and ultrasonically stir for 0.5 to 24 hours. The metal nanowires are dispersed into nickel or nickel-iron metal nanoparticles, and then the dispersed nickel or nickel-iron metal nanoparticles are placed in a sodium hydroxide solution with a pH value of 8 to 12 and stirred for 0.5 to 3 hours, and then transferred to a hydrothermal In the reaction kettle, keep the temperature at 80-120° C. for 2-10 hours and then naturally cool to room temperature, and the nickel or nickel-iron metal nanoparticles are recombined into nickel or nickel-iron metal nanowires. The invention realizes the dispersion and assembly of the nickel or nickel-iron nanometer metal wires through the control of the pH value, and realizes the control of the morphology of the nickel or nickel-iron nanometer material.

Description

Dispersion and assembly method of nickel or nickel-iron metal nanowires

technical field

The invention belongs to the field of nanometer materials, in particular to a method for dispersing and assembling nickel or nickel-iron metal nanowires.

Background technique

The discovery of carbon nanotubes in the 20th century has aroused widespread interest among scientists in other one-dimensional nanomaterials. When the size of the material is equal to or smaller than its characteristic length, such as Bohr radius, light wavelength, phonon free path, etc., quantum effects will become very noticeable. In terms of morphology, one-dimensional nanomaterials include nanowires, nanobelts, nanotubes, nanorods, etc. Among them, nanowire is a one-dimensional nanomaterial whose diameter is on the order of nanometers. Due to its large aspect ratio and the characteristics of two-dimensional limitation and one-dimensional conduction, nanowire has many unique optical and electromagnetic properties. In addition, as an ideal energy transmission material, the high aspect ratio of nanowires enables it to transmit quantized particles such as electrons, photons, and phonons, so it has very important applications in high-tech fields.

As magnetic materials, nickel-iron-based nanomaterials have unique electrical, magnetic and catalytic properties, and have shown great application potential in the fields of magnetic recording, catalysts, sensors and biomedicine.

After the development of nanomaterial preparation technology in recent decades, especially the emergence of major breakthroughs and innovations in the field of chemical synthesis, nanomaterials of various materials can be prepared within the scope of the laboratory. The preparation methods of nanowires include gas phase conversion method, chemical vapor deposition method, pulsed laser ablation method, electrodeposition method, sol-gel method, template method, hydrothermal method and microemulsion method. Especially in recent years, considerable progress has been made in the monodispersity, composition, size, shape, structure control and large-scale mass production of nanoparticles, such as the prepared gold nanorods with adjustable aspect ratio, Structure-controllable nickel-iron nanowires, etc. However, the current technology is mainly focused on the one-time synthesis of nanowires, and it is impossible to disassemble the nanowires, let alone reassemble after disassembly, which will not be conducive to the controllable operation of nanodevices composed of nanowires.

Contents of the invention

Aiming at the problems existing in the prior art, the present invention provides a method for dispersing and assembling nickel or nickel-iron metal nanowires. The purpose is to prepare nickel or nickel-iron nanowires by adopting hydrothermal synthesis and using hydrazine hydrate as a reducing agent. The control of the dosage of additive sodium citrate realizes the control of the morphology of nickel and nickel-iron nanomaterials, and realizes the mutual transformation and assembly of nanowires and nanoparticles through the regulation of pH value.

The technical scheme that realizes the object of the present invention carries out according to the following steps:

(1) Dissolve soluble nickel salt or a mixture of soluble nickel salt and soluble ferrous salt in deionized water to form a nickel salt or nickel-iron salt solution. Under the protection of nitrogen, add sodium citrate to the solution and mix well, add The ratio of sodium citrate to the total moles of nickel or nickel and iron is (1-2): 1, then add hydrazine hydrate, the hydrazine hydrate added is 20-60 times the total moles of nickel or nickel and iron, and the Transfer the above solution system to a hydrothermal reaction kettle, keep the temperature at 100-150°C for 1-10 hours, then cool it naturally to room temperature, wash the obtained product with deionized water and ethanol, and dry it with nitrogen to obtain nickel or nickel-iron metal nanowires ;

(2) Place the above-mentioned nickel or nickel-iron metal nanowires in a hydrochloric acid solution with a pH value of 3 to 6 and stir them ultrasonically for 0.5 to 24 hours, separate the magnetic products with a magnetic field, wash them twice with deionized water and ethanol, and wash them with nitrogen gas Drying, at this time, nickel or nickel-iron metal nanowires are dispersed into nickel or nickel-iron metal nanoparticles;

(3) Place the dispersed nickel or nickel-iron metal nanoparticles in a sodium hydroxide solution with a pH value of 8 to 12 and stir for 0.5 to 3 hours, then transfer to a hydrothermal reaction kettle, and keep the temperature at 80 to 120°C for 2 to 3 hours. After 10 hours, cool naturally to room temperature, separate the magnetic products with a magnetic field, wash twice with deionized water and ethanol, and blow dry with nitrogen. At this time, the nickel or nickel-iron metal nanoparticles are recombined into nickel or nickel-iron metal nanowires .

Wherein, the soluble nickel salt is nickel chloride, nickel sulfate, nickel nitrate, nickel acetate, and the soluble ferrous salt is ferrous sulfate, ferrous chloride, ferrous nitrate, ferrous acetate.

The soluble nickel salt and soluble ferrous salt can be mixed in any molar ratio.

The ratio of the deionized water to the soluble nickel salt or the mixture of the soluble nickel salt and the soluble ferrous salt is 100-1000ml of water per gram of the soluble nickel salt or the mixture of the soluble nickel salt and the soluble ferrous salt.

The ratio of the nickel or nickel-iron metal nanowires to hydrochloric acid is 100-200ml of hydrochloric acid per gram of metal nanowires.

The ratio of the nickel or nickel-iron metal nanoparticles to the sodium hydroxide solution is 100-200ml of the sodium hydroxide solution per gram of the metal nanoparticles.

Compared with prior art, feature and beneficial effect of the present invention are:

Nickel salt and iron salt are reduced to elemental nickel and elemental iron by hydrazine hydrate under alkaline conditions, and the reaction principle is as follows:

2Fe ²⁺ +4OH ^- +N ₂ H ₄ →2Fe+N ₂ +4H ₂ O(1);

2Ni ²⁺ +4OH ^- +N ₂ H ₄ →2Ni+N ₂ +4H ₂ O(2);

The nucleation reaction of nickel-iron alloy is as follows:

xNi+yFe=Ni _x Fe _y ; x=0～1, y=0～1; (3);

Side reactions produced during the reaction:

3N ₂ H ₄ →N ₂ +4NH ₃ (4);

The structural formula of sodium citrate is After the generation of nickel-iron-based magnetic particles, the negative ionic oxygen groups on the sodium citrate cover the surface of the newly formed nickel-iron-based magnetic particles, preventing them from further growing into large particles, which is also controlled by excessive sodium citrate. Particle size causes the formation of nanomaterials. At the same time, there are three negative oxygen ions on the sodium citrate molecule, which can be connected with other metal particles respectively to form large metal wires.

Similarly, if the pH value of the solution is adjusted in the range of 3 to 6, the negative oxygen ions of sodium citrate will combine with hydrogen ions step by step, thereby losing the adsorption capacity on the metal surface. Therefore, the pH value of the solution is adjusted so that the negative oxygen ions of sodium citrate combine with hydrogen ions, thereby dismantling the linear structure.

Adjust the pH value of the solution in the range of 8 to 12. The hydrogen ions combined with the sodium citrate negative oxygen ions are neutralized by the alkali, and the sodium citrate containing three negative oxygen ions is regained, that is, the three Therefore, the dispersed metal wires are reassembled into metal wires. The present invention realizes the dispersion and assembly of nickel or nickel-iron nanometer metal wires by controlling the pH value.

Description of drawings

Fig. 1 is the nickel nanowire prepared in the embodiment 1 of the present invention;

Fig. 2 is the nickel nanoparticle that disperses in the embodiment of the present invention 1;

Fig. 3 is the nickel nanowires reassembled in Example 1 of the present invention.

detailed description

Example 1

The method for dispersing and assembling the nickel metal nanowires of the present embodiment is carried out according to the following steps:

(1) Nickel chloride is dissolved in deionized water to form a nickel salt solution. The volume of deionized water is 100ml/g nickel chloride. Under nitrogen protection, sodium citrate is added to the solution and mixed uniformly. The added lemon The molar ratio of sodium bicarbonate to nickel is 2:1, then add hydrazine hydrate, the added hydrazine hydrate is 20 times the molar number of nickel, transfer the above solution system to a hydrothermal reaction kettle, keep the temperature at 150°C for 1 hour and then naturally Cool to room temperature, the product obtained is washed with deionized water and ethanol, and dried with nitrogen to obtain nickel metal nanowires, as shown in Figure 1;

(2) Place the above-mentioned nickel nanowires in a hydrochloric acid solution with a pH value of 4 and stir them ultrasonically for 15 hours. The ratio of the nickel nanowires to hydrochloric acid is 180ml of hydrochloric acid per gram of nickel metal nanowires, and the magnetic product is separated with a magnetic field. and ethanol were washed twice, and dried with nitrogen, at this time, the nickel nanowires were dispersed into nickel nanoparticles, as shown in Figure 2;

(3) the dispersed nickel nanoparticles are placed in a sodium hydroxide solution with a pH value of 11 and stirred for 0.5h. The ratio of the nickel nanoparticles to the sodium hydroxide solution is 100ml of sodium hydroxide solution per gram of nickel nanoparticles, and then transferred Put it into a hydrothermal reaction kettle, keep the temperature at 80°C for 10h, then cool it naturally to room temperature, separate the magnetic product with a magnetic field, wash it twice with deionized water and ethanol, and dry it with nitrogen. At this time, as shown in Figure 3, the nickel The nanoparticles were recombined into nickel nanowires.

Example 2

The method for dispersing and assembling the nickel-iron metal nanowires of the present embodiment is carried out according to the following steps:

(1) Mix and dissolve nickel sulfate and ferrous sulfate in deionized water according to the molar ratio of 2:1 to form a nickel-iron salt solution. The volume of deionized water is 500ml/g nickel-iron salt. Add sodium citrate and mix evenly, the ratio of the added sodium citrate to the total molar number of nickel and iron is 2:1, then add hydrazine hydrate, the added hydrazine hydrate is 40 times the total molar number of nickel and iron, the above The solution system was transferred to a hydrothermal reaction kettle, cooled to room temperature naturally after a constant temperature of 110°C for 8 hours, the obtained product was washed with deionized water and ethanol, and dried with nitrogen to obtain nickel-iron metal nanowires;

(2) above-mentioned nickel-iron nanowire is placed in the hydrochloric acid solution that pH value is 3 ultrasonically stirred 0.5h, the ratio of nickel-iron nanowire and hydrochloric acid is 200ml hydrochloric acid every gram of nickel-iron nanowire, magnetic product is separated with magnetic field, uses Wash twice with deionized water and ethanol, and blow dry with nitrogen. At this time, the nickel-iron nanowires are dispersed into nickel-iron nanoparticles;

(3) the nickel-iron nanoparticles after dispersion are placed in the sodium hydroxide solution that pH value is 8 and stir 1.5h, the ratio of nickel-iron nanoparticles and sodium hydroxide solution is 180ml sodium hydroxide solution every gram of nickel-iron nanoparticles , and then transferred to a hydrothermal reaction kettle, kept at 120°C for 2 hours, then naturally cooled to room temperature, separated the magnetic products with a magnetic field, washed twice with deionized water and ethanol, and dried with nitrogen. At this time, the nickel-iron nanoparticles are recombined into nickel-iron nanowires.

Example 3

The method for dispersing and assembling the nickel-iron metal nanowires of the present embodiment is carried out according to the following steps:

(1) Nickel nitrate and ferrous chloride are mixed and dissolved in deionized water according to a molar ratio of 3:1 to form a nickel-iron salt solution. The volume of deionized water is 1000ml/g nickel-iron salt. Add sodium citrate and mix evenly, the ratio of the added sodium citrate to the total molar number of nickel and iron is 1.5:1, then add hydrazine hydrate, the added hydrazine hydrate is 50 times the total molar number of nickel and iron, the The above solution system was transferred to a hydrothermal reaction kettle, cooled to room temperature naturally after a constant temperature of 120° C. for 5 hours, the obtained product was washed with deionized water and ethanol, and dried with nitrogen to obtain nickel-iron metal nanowires;

(2) above-mentioned nickel-iron nanowire is placed in the hydrochloric acid solution that pH value is 6 and is ultrasonically stirred for 24h, the ratio of nickel-iron nanowire and hydrochloric acid is 200ml hydrochloric acid per gram of nickel-iron nanowire, magnetic product is separated with magnetic field, uses Ionized water and ethanol were washed twice, and dried with nitrogen gas. At this time, the nickel-iron nanowires were dispersed into nickel-iron nanoparticles;

(3) the nickel-iron nanoparticles after dispersion are placed in the sodium hydroxide solution that pH value is 9 and stir 3h, the ratio of nickel-iron nanoparticles and sodium hydroxide solution is every gram of nickel-iron nanoparticles in 150ml sodium hydroxide solution, Then transfer to a hydrothermal reaction kettle, keep the temperature at 80-120°C for 2-10 hours, then cool naturally to room temperature, separate the magnetic product with a magnetic field, wash it twice with deionized water and ethanol, and dry it with nitrogen. At this time, the nickel Iron nanoparticles were reassembled into nickel-iron nanowires.

Example 4

The method for dispersing and assembling the nickel-iron metal nanowires of the present embodiment is carried out according to the following steps:

(1) Nickel acetate and ferrous nitrate are mixed and dissolved in deionized water according to a molar ratio of 1:9 to form a nickel-iron salt solution. The volume of deionized water is 800ml/g nickel-iron salt. Add sodium citrate and mix well. The ratio of the added sodium citrate to the total moles of nickel and iron is 1:1, and then add hydrazine hydrate. The added hydrazine hydrate is 60 times the total moles of nickel and iron. The solution system was transferred to a hydrothermal reaction kettle, and then naturally cooled to room temperature after being kept at 150°C for 1 hour. The obtained product was washed with deionized water and ethanol, and dried with nitrogen to obtain nickel-iron metal nanowires;

(2) Place the above-mentioned nickel-iron nanowires in a hydrochloric acid solution with a pH value of 5 and stir them ultrasonically for 0.5 to 24 hours. The ratio of the nickel-iron nanowires to hydrochloric acid is 150ml of hydrochloric acid per gram of nickel-iron nanowires, and the magnetic product is separated by a magnetic field. Wash twice with deionized water and ethanol respectively, and blow dry with nitrogen. At this time, the nickel-iron nanowires are dispersed into nickel-iron nanoparticles;

(3) Place the dispersed nickel-iron nanoparticles in a sodium hydroxide solution with a pH value of 10 and stir for 2.5h. The ratio of the nickel-iron nanoparticles to the sodium hydroxide solution is 200ml of sodium hydroxide solution per gram of the nickel-iron nanoparticles , and then transferred to a hydrothermal reaction kettle, kept at 100°C for 6 hours, then naturally cooled to room temperature, separated the magnetic products with a magnetic field, washed twice with deionized water and ethanol, and dried with nitrogen. At this time, the nickel-iron nanoparticles are recombined into nickel-iron nanowires.

Example 5

The method for dispersing and assembling the nickel-iron metal nanowires of the present embodiment is carried out according to the following steps:

(1) Nickel chloride and ferrous acetate are mixed and dissolved in deionized water according to a molar ratio of 5:1 to form a nickel-iron salt solution. The volume of deionized water is 600ml/g nickel-iron salt. Add sodium citrate and mix evenly, the ratio of the added sodium citrate to the total molar number of nickel and iron is 2:1, then add hydrazine hydrate, the added hydrazine hydrate is 30 times the total molar number of nickel and iron, the The above solution system was transferred to a hydrothermal reaction kettle, cooled to room temperature naturally after a constant temperature of 100° C. for 10 h, the obtained product was washed with deionized water and ethanol, and dried with nitrogen to obtain nickel-iron metal nanowires;

(2) above-mentioned nickel-iron nanowire is placed in the hydrochloric acid solution that pH value is 3 ultrasonically stirred 0.5h, the ratio of nickel-iron nanowire and hydrochloric acid is 100ml hydrochloric acid every gram of nickel-iron nanowire, separates magnetic product with magnetic field, uses Wash twice with deionized water and ethanol, and blow dry with nitrogen. At this time, the nickel-iron nanowires are dispersed into nickel-iron nanoparticles;

(3) the nickel-iron nanoparticles after dispersion are placed in the sodium hydroxide solution that pH value is 12 and stir 0.5h, the ratio of nickel-iron nanoparticles and sodium hydroxide solution is 100ml sodium hydroxide solution every gram of nickel-iron nanoparticles , and then transferred to a hydrothermal reaction kettle, kept at 90°C for 9 hours, then naturally cooled to room temperature, separated the magnetic products with a magnetic field, washed twice with deionized water and ethanol, and dried with nitrogen. At this time, the nickel-iron nanoparticles are recombined into nickel-iron nanowires.

Claims (6)

1. A method for dispersing and assembling nickel or nickel-iron metal nanowires, carried out according to the following steps: (1) Dissolve soluble nickel salt or a mixture of soluble nickel salt and soluble ferrous salt in deionized water to form a nickel salt or nickel-iron salt solution. Under the protection of nitrogen, add sodium citrate to the solution and mix well, add The ratio of sodium citrate to the total moles of nickel or nickel and iron is (1-2): 1, then add hydrazine hydrate, the hydrazine hydrate added is 20-60 times the total moles of nickel or nickel and iron, and the Transfer the above solution system to a hydrothermal reaction kettle, keep the temperature at 100-150°C for 1-10 hours, then cool it naturally to room temperature, wash the obtained product with deionized water and ethanol, and dry it with nitrogen to obtain nickel or nickel-iron metal nanowires ; It is characterized by: (2) Place the above-mentioned nickel or nickel-iron metal nanowires in a hydrochloric acid solution with a pH value of 3 to 6 and stir them ultrasonically for 0.5 to 24 hours, separate the magnetic products with a magnetic field, wash them twice with deionized water and ethanol, and wash them with nitrogen gas Drying, at this time, nickel or nickel-iron metal nanowires are dispersed into nickel or nickel-iron metal nanoparticles; (3) Place the dispersed nickel or nickel-iron metal nanoparticles in a sodium hydroxide solution with a pH value of 8 to 12 and stir for 0.5 to 3 hours, then transfer to a hydrothermal reaction kettle, and keep the temperature at 80 to 120°C for 2 to 3 hours. After 10 hours, cool naturally to room temperature, separate the magnetic products with a magnetic field, wash twice with deionized water and ethanol, and blow dry with nitrogen. At this time, the nickel or nickel-iron metal nanoparticles are recombined into nickel or nickel-iron metal nanowires . 2. the dispersion and assembly method of a kind of nickel or nickel-iron metal nanowire according to claim 1, it is characterized in that described soluble nickel salt is nickel chloride, nickel sulfate, nickel nitrate, nickel acetate, described Soluble ferrous salts are ferrous sulfate, ferrous chloride, ferrous nitrate, and ferrous acetate. 3. A method for dispersing and assembling nickel or nickel-iron metal nanowires according to claim 1, characterized in that said soluble nickel salt and soluble ferrous salt can be mixed in any molar ratio. 4. the method for dispersing and assembling a kind of nickel or nickel-iron metal nanowire according to claim 1, is characterized in that the ratio of the mixture of described deionized water and soluble nickel salt or soluble nickel salt and soluble ferrous salt It is 100-1000ml of water per gram of soluble nickel salt or a mixture of soluble nickel salt and soluble ferrous salt. 5. A method for dispersing and assembling nickel or nickel-iron metal nanowires according to claim 1, characterized in that the ratio of nickel or nickel-iron metal nanowires to hydrochloric acid is 100-200ml of hydrochloric acid per gram of metal nanowires Wire. 6. A method for dispersing and assembling nickel or nickel-iron metal nanowires according to claim 1, characterized in that the ratio of said nickel or nickel-iron metal nanoparticles to sodium hydroxide solution is 100-200ml of hydroxide Sodium solution per gram of metal nanoparticles.