JP2013159533A - Method for exfoliating carbon nanowall and method for recovering carbon nanowall - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate easily a carbon nano-block.SOLUTION: A method for exfoliating carbon nanowall and a method for recovering carbon nanowall have a step of charging liquid and a substrate 1 on which carbon nanowalls 2b are formed into an exfoliation tank, a step of exfoliating a carbon nano-block 2 constituted of one or a plurality of carbon nanowalls 2b from the substrate 1 by imparting ultrasonic wave into the exfoliation tank in which the substrate 1 on which the carbon nanowalls are formed exists, and a step of taking out the substrate 1 from which the carbon nano block 2 is exfoliated off from the liquid.

Description

  The present invention relates to a carbon nanowall peeling method formed of one or a plurality of carbon nanowalls and a carbon nanowall recovery method.

  In recent years, carbon nanowalls have attracted attention as a new material, and many researches have been advanced (see, for example, Patent Document 1, Patent Document 2, and Non-Patent Document 1). The carbon nanowall is a two-dimensional carbon material having a curved sheet upright on the substrate. This carbon nanowall is composed of crystallites with good crystallinity.

  Carbon nanowalls are expected to be used as metal carriers and as secondary battery electrode materials due to their structural characteristics. Since the carbon nanowall is formed on the substrate, when the carbon nanowall is used as a material for the electrode of the secondary battery, the carbon nanowall is used as a substrate to apply the carbon nanowall to the object. Need to be peeled off.

JP 2009-242192 A JP 2010-009980 A

K. Kobayashi and 6 others, “Nanographite domains in carbon nanowalls”, J. Appl. Phys. 101, 094306, 2007

  However, at present, an optimum method for peeling the carbon nanowall from the substrate has not been proposed.

  In view of the above problems, an object of the present invention is to provide a carbon nanowall peeling method and a recovery method for easily peeling carbon nanowalls.

  In order to achieve the above object, the invention according to claim 1 is characterized in that a liquid and a substrate on which carbon nanowalls are formed are placed in a peeling tank, and the peeling tank in which a substrate on which carbon nanowalls are formed exists. Applying ultrasonic waves to the substrate to separate the carbon nanowall lump composed of one or a plurality of carbon nanowalls from the substrate, and removing the substrate from which the carbon nanowall lump has been peeled from the liquid. And

  In addition, the invention of claim 2 is characterized by having a step of separating the carbon nanowall lump from the liquid containing the carbon nanowall lump after the substrate is taken out.

  The invention of claim 3 is characterized in that the carbon nanowall lump is separated from the liquid by evaporating the liquid containing the carbon nanoblocks.

  The invention of claim 4 is characterized in that the carbon nanowall lump is separated from the liquid using a filter.

  According to the present invention, the carbon nanowall can be peeled from the substrate on which the carbon nanowall is formed by an easy treatment.

It is the schematic explaining the structure of carbon nanowall. It is an example of the SEM image of the carbon nanowall peeled from the board | substrate. It is another example of the SEM image of the carbon nanowall peeled from the substrate. It is an example of a Raman scattering spectrum.

  In the carbon nanowall peeling method according to the embodiment of the present invention, there are a step (step 1) of putting a liquid and a substrate on which carbon nanowalls are formed into a peeling tank, and a substrate on which carbon nanowalls are formed. Applying ultrasonic waves to the peeling tank to peel a carbon nanowall lump composed of one or a plurality of carbon nanowalls from the substrate (step 2), and taking out the substrate from which the carbon nanowall lump has been peeled from the liquid ( Step 3).

  As shown in FIG. 1, the carbon nanowall 2b is composed of a plurality of graphite crystals (nanographite) 2c, and is formed on the graphite layer 2a. The graphite layer 2a is composed of a plurality of graphite crystals 2c on the substrate 1 like the carbon nanowall 2b.

  In the example shown in FIG. 1, a graphite layer 2a is formed on a part of the substrate 1, and only two carbon nanowalls 2b are formed on the graphite layer 2a. However, generally, the graphite layer 2a is widely formed on the substrate 1, and two or more carbon nanowalls 2b are formed on the graphite layer 2a. Moreover, as shown in FIG. 1, the structure which has the several carbon nanowall 2b on the graphite layer 2a is made into the carbon nanowall lump 2. FIG.

(Step 1)
First, the substrate 1 on which the carbon nanowall 2b is formed and the liquid are put into a peeling tank (not shown). The liquid put into the peeling tank together with the substrate 1 may be any material that does not cause a chemical reaction with the substrate 1 such as ethanol or the graphite crystal 2c on the substrate 1, for example. The peeling tank is, for example, a water tank of a beaker or an ultrasonic cleaner.

(Step 2)
Next, ultrasonic waves are applied to the substrate 1 on which the carbon nanowalls 2b are formed and the peeling tank in which the liquid is present to peel the carbon nanowalls 2b from the substrate 1 as the carbon nanowall lump 2 configured with the graphite layer 2a. . For example, when the peeling tank is a beaker, the beaker is placed in a water tank of an ultrasonic cleaner to apply ultrasonic waves to the liquid in the beaker. Further, when the peeling tank is a water tank of an ultrasonic cleaner, ultrasonic waves are applied to the liquid in the water tank.

(Step 3)
Subsequently, the substrate 1 from which the carbon nanowall lump 2 has been peeled is taken out of the liquid.

(Step 4)
Thereafter, the carbon nanowall lump 2 is separated from the liquid. For example, only the carbon nanowall lump 2 can be recovered by putting a beaker in which a liquid containing the peeled carbon nanowall lump 2 exists in an oven and evaporating the liquid. Alternatively, the carbon nanowall lump 2 may be collected by filtering a liquid containing the carbon nanowall lump 2. In addition, the liquid containing the carbon nanowall lump 2 is swirled using a centrifuge, the carbon nanowall lump 2 is precipitated and the supernatant liquid is removed, and then only the liquid is evaporated to recover the carbon nanowall lump 2. May be.

  Thus, in the carbon nanowall peeling method according to the embodiment, the carbon nanowall lump 2 is separated (peeled) from the substrate 1 on which the carbon nanowall 2b is formed using ultrasonic waves. Further, since the carbon nanowalls are subsequently recovered, the carbon nanowalls 2b generated on the substrate 1 can be easily used. Further, when the substrate 1 is rubbed with a scraper or the like, the fine powder of the substrate 1 or the like may be included in the collected carbon nanowall 2b. Mixing problems can be prevented. Furthermore, since the separation of the carbon nanowalls 2b from the substrate 1 also serves as the cleaning of the substrate by peeling off with ultrasonic waves, the substrate after the separation of the carbon nanowalls 2b can be reused immediately.

<Example>
Subsequently, an example of a carbon nanowall lump that has been peeled and recovered by the carbon nanowall peeling method and the recovery method of the present invention will be described. An example of the SEM image of the carbon nanowall lump peeled and recovered in this way is shown in FIG. FIG. 2 shows a carbon nanowall lump generated by placing a silicon substrate on which a plurality of carbon nanowalls 2b are formed in an ethanol solution and applying ultrasonic waves. FIG. 2B is an image taken at a higher magnification than that in FIG. In the SEM image of FIG. 2, a carbon nanowall lump having a plurality of carbon nanowalls 2b is photographed. In the example shown in FIG. 2B, the surface on which the carbon nanowalls 2b of the carbon nanowall lump exist is the front surface 2A, and the surface in contact with the substrate 1 is the back surface 2B. Moreover, FIG. 3 is an example of the SEM image which expanded the carbon nanowall lump further.

  In FIG. 4 (a), ultrasonic waves are applied for 10 minutes to a beaker containing methanol and a silicon substrate on which carbon nanowalls are formed (ultrasonic output 125W), and the carbon nanowall lump separated and recovered from the silicon substrate. The Raman scattering spectrum of is shown. FIG. 4B shows an example of the Raman scattering spectrum of the carbon nanowall formed on the substrate. Comparing each spectrum shown in FIG. 4, the peak in the spectrum of the carbon nanowall mass recovered by the carbon nanowall peeling method of the present invention is not significantly different from the peak in the spectrum of the carbon nanowall generated on the substrate. Absent. Therefore, it can be seen that the carbon nanowall lump was peeled off from the substrate without destroying the structure of the carbon nanowall.

  As mentioned above, although this invention was demonstrated in detail using embodiment, this invention is not limited to embodiment described in this specification. The scope of the present invention is determined by the description of the claims and the scope equivalent to the description of the claims.

DESCRIPTION OF SYMBOLS 1 ... Substrate 2 ... Carbon nanowall lump 2A ... Front surface 2B ... Back surface 2a ... Graphite layer 2b ... Carbon nanowall 2c ... Graphite crystal

Claims (5)

Introducing a liquid and a substrate on which carbon nanowalls are formed into a peeling tank;
Peeling the carbon nanowall lump composed of one or a plurality of carbon nanowalls from the substrate by applying ultrasonic waves to the peeling tank in which the substrate on which carbon nanowalls are formed exists;
Removing the substrate from which the carbon nanowall lump has been peeled from the liquid;
Method for peeling carbon nanowall having   A method for recovering carbon nanowalls, comprising a step of separating carbon nanowall lumps from a liquid containing carbon nanowall lumps after the substrate is taken out by the carbon nanowall peeling method according to claim 1. The method for recovering carbon nanowalls according to claim 2, wherein the carbon nanowall lump is separated from the liquid by evaporating the liquid containing the carbon nanowall lump. The method for recovering carbon nanowalls according to claim 2, wherein the carbon nanowall lump is separated from the liquid using a filter. The method for recovering carbon nanowalls according to claim 2, wherein the carbon nanowall lump is separated from the liquid using centrifugation.