阅读说明：本技术 包含稳定碳炔链的层及其制备方法 (Layer comprising a stable carbyne chain and method for the production thereof ) 是由 阿丽娜·卡拉布切夫斯基 于 2019-09-05 设计创作，主要内容包括：本发明涉及一种包含多个线性碳炔链的层的制备方法,该方法包括(a)对液体中的一块次石墨进行激光烧蚀,然后在稳定化金属纳米粒子的存在下对液体内所得到的碳结构进行激光辐照,从而形成胶体溶液；和(b)使所述胶体溶液的至少一部分经受AC电压,同时使得所述溶液干燥,从而形成包含多个碳炔链的二维层。(The invention relates to a method for preparing a layer comprising a plurality of linear carbyne chains, which comprises (a) carrying out laser ablation on a piece of graphite in a liquid, and then carrying out laser irradiation on a carbon structure obtained in the liquid in the presence of stabilized metal nanoparticles, thereby forming a colloidal solution; and (b) subjecting at least a portion of the colloidal solution to an AC voltage while allowing the solution to dry, thereby forming a two-dimensional layer comprising a plurality of carbyne chains.)

1. A method of making a layer comprising a plurality of linear carbyne chains, comprising:

a) performing laser ablation on a piece of graphite in liquid, and then performing laser irradiation on the obtained carbon structure in the liquid in the presence of stabilized metal nanoparticles to form a colloidal solution; and

b) subjecting at least a portion of the colloidal solution to an AC voltage while drying the solution, thereby producing a two-dimensional layer comprising a plurality of carbyne chains.

2. The method of claim 1, wherein the stabilized nanoparticles are made of gold.

3. The method of claim 1, wherein the liquid is deionized water.

4. The method of claim 1, wherein the laser ablating step comprises:

a) performing first laser irradiation on the graphite in the liquid to obtain individual carbon flakes in the liquid; and

b) the subsequent laser irradiation comprises a second laser irradiation of the individual carbon flakes within the liquid, after removing the remaining hypographites and adding gold nanoparticles to the liquid, resulting in the colloidal solution.

5. The method of claim 1, wherein the energy applied by the first laser shot is substantially higher than the energy applied by the second laser shot.

6. The method of claim 1, wherein the frequency of the AC voltage is in a range between 0.5Hz and 5 Hz.

7. A two-dimensional layer comprising a plurality of carbyne chains.

Technical Field

The present invention relates generally to the field of material formation. More particularly, the invention relates to a process for preparing stabilized carbyne from hypographite.

Background

Different forms of carbon have long been the subject of considerable research by chemists, physicists and engineers. Diamond, graphene, carbon nanotubes and fullerenes, to name a few, have a wide variety of different properties. For example, graphene and nanotubes have recently made major breakthroughs in advanced science and technology. Researchers who discovered fullerenes in the eighties of the twentieth century acquired a nobel prize in 1996. Other researchers who discovered a relatively simple method of producing graphene from graphite, Andrew geom and Konstantin Novoselov, in 2010, obtained the nobel prize in physics due to "a pioneering experiment on two-dimensional material graphene (for grouping experiments on the two-dimensional material graphene)". Recently, a new carbon-based Q-carbon material has been produced. There is still much interesting research and room to find new carbon-based materials.

Carbon is capable of forming many allotropes (different forms of the same element in structure) due to its valence. The most basic of these allotropes include diamond, graphite, graphene, and carbyne (carbyne). Diamond being a single bond tetrahedral sp³A three-dimensional network of carbon atoms. The graphene has sp formed as a two-dimensional layer²Structure, and consists of diatomic and monoatomic bonds. Graphite is a two-dimensional sp consisting of a plurality of graphene-like layers laminated to each other²And (5) structure. In graphite, orbital hybridization and atoms form in a plane, each atom being bonded to three nearest neighbor atoms that are 120 ° apart. The atoms in each graphite plane are covalently bonded, while only three of the four potential bonds per atom are satisfied. The fourth electron is free to migrate in-plane, rendering the graphite conductive. However, it is not electrically conductive in a direction at right angles to the plane. The bond between the graphite layers is weak, which makes the graphite layers easily separated or slid with respect to one another.

Diamond has the highest hardness and thermal conductivity of any natural material, and these properties are utilized in major industrial applications such as cutting tools and polishing tools. Graphene, which is proportional to thickness, is about 100 times stronger than the strongest steel. It conducts heat and electricity very efficiently and is almost transparent.

In the last decades, more allotropes or carbon forms including spherical forms such as buckminster fullerenes and sheet forms such as graphene have been discovered and studied. Larger scale structures of carbon include nanotubes, nanobuds and nanobelts. Other unusual forms of carbon are also present at very high temperatures or very high pressures.

Carbynes have the form of a linear (one-dimensional) chain of carbon atoms arranged in an sp structure. The atoms in the carbyne chain are bonded with (a) alternating three-one electron bonds or (b) two electron bonds. According to theoretical predictions, carbyne has significantly superior mechanical properties compared to all known materials. For example, carbyne is 40 times harder than diamond, 2 times harder than graphene, and has a higher tensile strength than all other carbon materials. Furthermore, the predicted mechanical and electronic properties of carbynes present many new directions in the design of nanoelectronic and opto-mechanical devices. However, carbynes are extremely unstable at ambient temperatures and therefore in practice none of these properties of carbynes can be exploited.

Many attempts have been made to produce carbyne that is stable at ambient temperatures. For example, Pan et al in sci.adv.2015 10 months 2015; el500857 "carbyne of finite length: the two-stage process of forming Carbyne is proposed in One-Dimensional sp Carbon (Carbyne with finished Length: The One-Dimensional sp Carbon). In the first stage, a solution of the substance is synthesized using the "laser ablation in liquid" (LAL) technique, and in the second stage, the solution is purified using high performance liquid chromatography techniques, resulting in a chain of carbyne atoms. Shi et al in 2016.6 in "restricted Linear Carbon Chains as pathways to Bulk Carbyne" (defined Linear Carbon Chains as a Route to Bulk Carbyne) "volume 15 of natural Materials (Nature Materials) proposed a technique for forming long Carbyne Chains that can contain up to 6000 atoms. However, the Shi et al technique requires heating the material to very high temperatures ranging from 900 ℃ to 1450 ℃.

Graphite (Shungite) is a black, lustrous, amorphous mineral that consists of over 97-98% carbon by weight. It was originally described as a deposit found near Shunga village (from which its name was obtained) in Karelia, russia. It is likely that this is one of the very few locations on earth where such mineral rocks can be found. Other findings have been reported in austria, india, democratic republic of congo and kazakhstan. It is reported that the sub-graphite contains a trace amount of fullerene. The term "hypographites" was originally used in 1879 to describe mineraloids with carbon contents in excess of 97-98%. More recently, the term has also been used to describe sub-graphitic rocks. Graphites containing rocks have also been classified according to the purity of their carbon content. In the context of the present invention, the term "graphite" not only means minerals with a carbon content of > 97-98% (e.g. minerals located in Russia), but also graphite with any rock with a carbon content of the minerals higher than 96%.

It is an object of the present invention to provide a simple technique for producing carbyne which remains stable at ambient temperature at the end of the process.

It is yet another object of the present invention to provide a technique for producing stable carbyne that can be performed entirely at ambient temperature.

Other objects and advantages of the invention will become apparent as the description proceeds.

Disclosure of Invention

The invention relates to a method for producing a layer comprising a plurality of linear carbyne chains, comprising a) laser ablation of a piece of graphite in a liquid, followed by laser irradiation of the carbon structure obtained in the liquid in the presence of stabilized metal nanoparticles, thereby forming a colloidal solution; and b) subjecting at least a portion of the colloidal solution to an AC voltage while drying the solution, thereby producing a two-dimensional layer comprising a plurality of carbyne chains.

In an embodiment of the invention, the stabilized nanoparticles are made of gold.

In an embodiment of the invention, the laser ablation step comprises: a) performing first laser irradiation on the graphite in the liquid to obtain individual carbon flakes in the liquid; and b) the subsequent laser irradiation comprises a second laser irradiation of the individual carbon flakes within the liquid after removing the remaining hypographites and adding gold nanoparticles to the liquid, thereby obtaining the colloidal solution.

In embodiments of the invention, the energy applied by the first laser irradiation is significantly higher than the energy applied by the second laser irradiation.

The invention also relates to a two-dimensional layer comprising a plurality of carbyne chains.

Drawings

In the drawings:

figure 1 schematically shows a first stage of the method of the invention;

figures 2 a-2 c schematically show a first (LAL) phase of the invention; and is

Figure 2d schematically shows a second phase of the method of the invention;

figure 2e shows XPS spectra of a sample of sub-graphite used as starting material in the process;

FIG. 3 is another illustration of the second phase of the method of the invention;

figure 4a is an image showing the droplets on the copper mesh substrate without any voltage being supplied to the electrodes during the second phase of the method of the invention;

figure 4b is an image showing the dried sample after the electrodes have previously been subjected to 9V AC at a frequency of 1Hz in the second phase of the invention.

Figure 4c is an enlarged portion of the image of figure 4 b; and is

Figure 4d shows the comparative results obtained for the dried samples after the electrodes were subjected to a DC voltage of 9V.

Detailed Description

As previously mentioned, carbyne is a carbon allotrope that is 40 times harder than diamond, 2 times harder than graphene, and has a higher tensile strength than all other carbon materials. However, since carbyne is unstable at ambient temperature, it cannot be found in nature.

The inventors have found a simple process for producing a two-dimensional layer comprising a plurality (in fact a plurality) of carbyne chains. The entire process can be carried out at ambient temperature. After this process is complete, the carbyne chain remains stable in the layer at ambient temperature. It has been found that two types of layers can be produced by the present invention: (a) a layer consisting of alternating chains of three-single bonded carbon atoms; and (b) a layer consisting of a chain of double-bonded carbon atoms. According to the invention, the carbyne chain is prepared from graphite.

The process of the present invention for preparing a carbyne from a hypographite is basically a two-stage process, which can be roughly described as generating a colloidal solution containing gold-terminated linear carbon chains obtained from a hypographite starting material by means of laser irradiation, and applying an AC voltage to the solution, respectively.

The first stage (actually comprising two different irradiation steps) starts with the laser ablation step 100 shown in fig. 1. A sample (target) 102 of raw sub-graphite is added to a volume of deionized water 104 (in one example, a 3mm piece) in a container 106³To 1mL of deionized water). Then, the sub-graphite was irradiated by LAL (laser in liquid) first-step irradiation. A plurality of unstable chains of carbon atoms (not shown) are formed within the deionized water 104. These chains are unstable because of the lack of two "anchor" atoms at each end of the chain, whose atoms "try" to connect to other chains in the liquid in some irregular and uncontrolled manner. More specifically, they do not form stable carbyne chains (which is expected since carbyne chains are known to be unstable at ambient temperatures).

Then, in a second irradiation step of the first stage, the remaining sub-graphite 102 is removed from the liquid, and gold (Au) nanoparticles (in one example, 60nm in diameter) are added to the solution (not shown). The previously formed linear chains are laser irradiated with the gold nanoparticles to activate the linkage of the linear carbon chains to the anchoring gold nanoparticles.

The laser irradiation stage 100 described above is substantially as described in Pan et al-see the "background" section above. The laser irradiation stage is performed by the laser generator 110.

At the end of the laser ablation/laser irradiation phase 100 in the liquid, a portion from the liquid 104 with labile carbon chains therein is placed on the substrate 202, as shown in the schematic top view of fig. 2 d.

Figure 2d illustrates a second stage of the process for producing a stable carbyne chain. In the second stage, the substrate 202 is placed on two electrodes (e.g., each having 1 mm)²Area) 206a and 206 b. An AC voltage (9V, 1Hz in one example) is applied to both electrodes. It has surprisingly been found that an AC voltage results in the production of a plurality of discrete carbyne chains in water, each of which is anchored at both ends by two gold atoms. In fact, each chain produced comprises a plurality of carbon atoms, anchored at their ends by two gold atoms. Each generated chain is parallel to the other chains to some extent. Most importantly, it has also been found that the carbyne chain remains stable within the formed 2D layer after the water dries (while still applying an AC voltage to the electrodes 206a and 206 b).

Interestingly, as shown below, the application of a DC voltage instead of an AC voltage in the second stage of the process does not result in the generation of gold atom terminated carbyne chains, but rather in the generation of "carbon cages" in which gold nanoparticles are encapsulated. Thus, one independent aspect of the technology disclosed herein is a process for encapsulating nanoparticles (e.g., gold nanoparticles), wherein in a second stage of the process, a DC voltage is applied.

Experiment of

The first stage of the process comprises two laser irradiation steps. Fig. 2a to 2c schematically show this stage performed experimentally by the inventors. Initially, as shown in FIG. 2a, a block is provided having a thickness of 3mm³A volume of the sub-graphitic mineral (target) (sample) was placed in a container with 1mL of deionized water. Next, the sub-graphite sample was subjected to a first step of laser irradiation, i.e. laser ablation was accomplished by irradiation with 1064nm, 0.5ms pulsed, 50Hz, 7J laser. The laser irradiation produces a plurality of individual carbon flakes. In the next step, shown in fig. 2b, the remaining hypo-graphite is removed from the liquid and the gold is washed off(Au) nanoparticles (GNP) (60 nm in diameter, respectively, purchased from Sigma Aldrich) were added to the liquid. The liquid containing the carbon flakes and GNPs was then subjected to a second step of laser irradiation-1064 nm, 100ns pulse, 30kHz, 0.5 mJ. The first stage as described in fig. 2a to 2b results in a colloidal solution comprising linear carbon chains, each chain having GNP atoms at each of the two ends of the chain (fig. 2 c). Figure 2e shows XPS spectra of a sub-graphitic mineral used as the starting material. Energy spectrum indicates carbon content>97％。

Fig. 3 and 2d show the second phase of the process of the invention. In non-binding theory, the inventors believe that the explanation for this phenomenon lies in Lorentz Law (Lorentz Law). A sample of the resulting liquid from fig. 2c is placed on a substrate 202 made of copper mesh. Two metal electrodes 206a and 206b are placed beside the substrate 202. The radius of each electrode was 1mm and they were spaced 1mm from each other. The electrodes are connected to an AC power supply which in this particular case operates with an amplitude of 9V and a frequency of 1 Hz. It is noted that the same results were obtained in the frequency range of 0.5Hz-5Hz (resolution step was tested at 0.5 Hz). The AC voltage was applied for 1 hour.

The electrodes generate an electromagnetic field which in turn causes an electric current to flow in the carbon filament. The lorentz force between the current and the magnetic field stretches the filaments (chains) in the liquid. As the liquid dries naturally, the filaments are stretched and aligned on the substrate 202. The direction of the electric field E changes direction together with the magnetic field B, which changes the direction of rotation (clockwise or counterclockwise of the magnetic field B). More specifically, a current is induced on the carbon filament due to a magnetic field that varies under the AC current. Thus, in a magnetic field, the current-carrying carbon filament is subjected to a lorentz force F in a direction given by fleming's left-hand law, which has a magnitude:

F＝BIlsinθ

where F is the force, l is the length of the carbon filament in the magnetic field, I is the current flowing through the carbon filament, and θ is the angle between the carbon filament and the magnetic field having a magnetic field strength B. It should be noted that the direction of the force F does not change even if the carbon filament is positioned at an angle θ with respect to the magnetic field. This explains the fact that the carbon filaments deposited on the substrate have an angle. A stretching perpendicular to the direction E of the electromagnetic field between the two electrodes is achieved.

The experimental results were studied using a high resolution Transmission Electron Microscope (TEM). Figure 4a shows an image of a droplet on a copper mesh substrate without any voltage applied to the electrodes 202. It can be appreciated that the image does not show any particular order of atoms. The darker parts represent the collection of gold nanospheres each having a diameter of 60 nm. Figure 4b shows an image of the dried droplet (i.e. after drying) after the electrode was previously subjected to 9V, 1Hz AC. Fig. 4c shows an enlarged portion of the image of fig. 4 b. It can be clearly seen that a number of stable chains of carbon atoms are achieved.

Figure 4d shows the comparison results obtained for dried droplets after subjecting the electrodes to a DC voltage of 9V (instead of 9V AC as performed in previous tests). It can clearly be seen that there are no chains. Instead, it can be appreciated that the carbon atoms encapsulate the gold "anchor" atoms (the gold atoms are represented by the darker portion of the center of the image).

The inventors believe that the carbyne chains implemented in the images of fig. 4b and 4c actually reflect two types of bonds: (a) alternating three-single bonds; and/or (b) a double bond. In both cases, electrons from the gold atom are used as anchors at both ends of the chain. The inventors also believe that there is no limit to the length of the carbyne chain that can be produced by the present invention. The larger the sub-graphite sample and the longer the time used in the first stage of laser ablation, the longer the carbyne chain can be obtained.

As shown, the present invention provides a simple method for producing a stable linear carbyne chain at ambient temperature. Carbyne chains can have many important and valuable applications due to their unique properties, for example, very strong ropes can be made from a plurality of such carbyne chains. Other examples are new types of extremely hard and durable materials and textiles.

Although some embodiments of the invention have been described by way of example, it will be obvious that the invention may be carried out with many modifications, variations and adaptations, and with the use of numerous equivalents or alternative solutions that are within the scope of persons skilled in the art, without departing from the spirit of the invention or exceeding the scope of the claims.