WO2021125782A1 - Microporous hollow carbon black and manufacturing method therefor - Google Patents

Abstract

The present invention relates to a hollow carbon black having micropores and a manufacturing method therefor, wherein the present invention is utilized as a support inside which a different substance can be packed and is applicable as a material in various fields, such as electrocatalytic supports, carbon supports, anode materials, and cathode materials for secondary batteries or fuel cells.

Description

Microporous hollow carbon black and manufacturing method thereof

The present invention relates to a hollow carbon black having microporous pores and a method for manufacturing the same, which can be used as a support that can be filled with other materials therein, and can be used as an electrocatalyst support for a secondary battery or a fuel cell. It is an invention that can be applied to materials in various fields such as members, carbon supports, negative electrode materials, and positive electrode materials.

Carbon black is widely used as a black pigment, as a reinforcing agent, as a filler, and the like. Carbon black is produced with different properties by different methods. The most common method is the production method by oxidative pyrolysis of carbon-containing carbon black raw materials. In this case, the carbon black raw material is burned incompletely in the presence of oxygen at a high temperature. Examples of this class of carbon black production method include a furnace black method, a gas black method and a lamp black method. Examples of other methods include an acetylene method, a thermal black method, and a plasma method.

In addition, carbon black is used as a conductive material for manganese batteries, lithium batteries, secondary batteries, etc., due to the characteristic of having high conductivity, and it is known that the more micropores there are in the aggregate of carbon black, the greater the capacity is, and research aimed at large batteries is being carried out. In fuel cells, it is used as a catalyst carrier for the catalyst layer, and studies are being conducted to control the specific surface area of carbon black to reduce the amount of expensive platinum catalyst added and increase the active area. For example, various attempts have been made to form pores by chemically activating the surface of carbon black, or to increase energy storage by maintaining conductivity by introducing a mixed secondary structure between carbon blacks.

As a result of repeated research for controlling the specific surface area of carbon black, the present inventors have completed the present invention by preparing carbon black with a significantly increased micropore volume and increased specific surface area of furnace carbon black among carbon black. .

As described above, an object of the present invention is to provide a microporous hollow carbon black having a significantly increased specific surface area and an increased micropore volume compared to the raw material carbon black and a method for manufacturing the same.

The present invention for solving the above problems relates to microporous hollow carbon black, which is a furnace carbon black prepared by performing vapor phase oxidation reaction of furnace carbon black using an oxidizing gas, which has a hollow structure and has micropores The eggplant contains furnace carbon black.

As a preferred embodiment of the present invention, the microporous hollow carbon black of the present invention may have a micropore volume satisfying Equation 1 below.

[Equation 1]

2.0 ≤ B/A ≤ 7.0

In Equation 1, A is the micropore volume of the furnace carbon black before the gas phase oxidation reaction is performed, and B is the micropore volume of the furnace carbon black subjected to the gas phase oxidation reaction.

As a preferred embodiment of the present invention, the microporous hollow carbon black of the present invention may have a BET specific surface area of 180 to 1,200 m ² /g.

As a preferred embodiment of the present invention, the microporous hollow carbon black of the present invention may have a total pore volume of 0.190 to 1.200 cm ³ /g.

As a preferred embodiment of the present invention, in the microporous hollow carbon black of the present invention, the average particle diameter of the micropores may be 4.0 to 8.0 nm.

Another object of the present invention relates to a method for producing the aforementioned microporous hollow carbon black, comprising: a first step of preparing the furnace carbon black; and a second step of performing a gas phase oxidation reaction of the furnace carbon black using an oxidizing gas.

As a preferred embodiment of the present invention, the micropore volume of the furnace carbon black subjected to the two-step gas phase oxidation reaction may satisfy the following equation.

[Equation 1]

2.0 ≤ B/A ≤ 7.0

In Equation 1, A is the micropore volume of the furnace carbon black before the gas phase oxidation reaction is performed, and B is the micropore volume of the furnace carbon black subjected to the gas phase oxidation reaction.

As a preferred embodiment of the present invention, the gas phase oxidation reaction is performed in an oxidation chamber, and while supplying an oxidizing gas in the oxidation chamber under 850° C. to 1200° C., it can be performed for 30 minutes to 150 minutes. have.

As a preferred embodiment of the present invention, the oxidizing gas may contain 99.000 ~ 99.999% by volume of CO ₂ .

As a preferred embodiment of the present invention, the gas phase oxidation reaction may be performed while supplying the oxidizing gas into the oxidation chamber at a rate of 50 to 200 mL/min.

In addition, another object of the present invention relates to an application using the microporous hollow carbon black described above, comprising an electrocatalyst carrier for a fuel cell comprising the microporous hollow carbon black, and the microporous hollow carbon black To provide a carbon support for secondary batteries, etc.

The carbon black produced by the production method of the present invention increases the micropore volume by at least 2 times and at most 6 times that of the furnace carbon black before the gas phase oxidation treatment, and as a result, the micropore volume having a high specific surface area and high total pore volume. of hollow furnace carbon black can be produced. And, as shown schematically in FIG. 1, unlike carbon black with a conventional porous structure, it has a hollow shape, and the microporous hollow furnace carbon black of the present invention can support various materials and has excellent electrical properties. , can be used as a material in a wide variety of fields.

1 is a schematic diagram for explaining the structural difference between the porous carbon black before the gas phase oxidation reaction and the microporous hollow carbon black of the present invention subjected to the acid oxidation reaction.

2 is a schematic diagram of an oxidation chamber used for a gas phase oxidation reaction in the present invention.

3 to 6 are TEM measurement photographs of microporous hollow furnace carbon black prepared by performing gas phase oxidation reaction at 1,000° C. for different reaction times.

Hereinafter, the present invention will be described in more detail through a method for producing the microporous hollow carbon black of the present invention.

Step 1 of preparing the furnace carbon black of the present invention; and a second step of performing a gas phase oxidation reaction of the furnace carbon black using an oxidizing gas to prepare a microporous hollow carbon black.

As the furnace carbon black in step 1, commercially available furnace carbon black may be used, and preferably at least one selected from the brand name Super-p and the brand name C-NERGY. Furnace carbon black containing may be used.

The vapor-phase oxidation reaction of the second step may be performed in the oxidation chamber schematically shown in FIG. 2, and after furnace carbon black is introduced into the oxidation chamber, the vapor-phase oxidation reaction may be performed while supplying an oxidizing gas into the oxidation chamber.

The gas phase oxidation reaction may be performed for 30 minutes to 150 minutes under 850° C. to 1200° C. while supplying a chemical gas in the oxidation chamber, preferably for 40 minutes to 120 minutes under 900° C. to 1150° C., more preferably Preferably, it can be carried out for 45 minutes to 110 minutes under 950 ° C. to 1100 ° C. If the gas phase oxidation reaction temperature is less than 850° C. or the gas phase oxidation reaction time is less than 30 minutes, there may be a problem in that the specific surface area, micropore volume, and total pore volume of the furnace carbon black subjected to the gas phase oxidation reaction are low. In addition, when the gas phase oxidation reaction temperature exceeds 1200° C. or the gas phase oxidation reaction time exceeds 150 minutes, the physical properties such as specific surface area and micropore volume of carbon black no longer increase, as well as pores (voids) Since there may be problems in that the retaining wall becomes thin and the pore shape is broken, the mechanical strength of carbon black is too low and thus easily brittle, and the manufacturing yield is greatly reduced, so it is preferable to carry out under the above temperature.

As the oxidizing gas, CO ₂ is used, preferably 99.000 to 99.999 vol%, preferably 99.500 to 99.999 vol%, more preferably 99.800 to 99.999 vol%, CO ₂ is preferably used. Then, the gas phase oxidation reaction may be performed while supplying the oxidizing gas into the oxidation chamber at a flow rate of 50 to 200 mL/min, preferably 80 to 150 mL/min, and more preferably 85 to 120 mL/min.

And, the burn-off yield of the microporous hollow carbon black prepared by the above method may be 25.0% to 65.0%, preferably 30.0 to 63.0%, more preferably 35.0 to 55.0%.

The microporous hollow carbon black of the present invention prepared by this method has a hollow structure having micropores as schematically shown in FIG. 1 , and may have a micropore volume satisfying Equation 1 below.

[Equation 1]

2.0 ≤ B/A ≤ 7.0, preferably 2.5 ≤ B/A ≤ 6.8, more preferably 3.0 ≤ B/A ≤ 6.5

In Equation 1, A is the micropore volume of the furnace carbon black before the gas phase oxidation reaction is performed, and B is the micropore volume of the furnace carbon black subjected to the gas phase oxidation reaction.

In addition, the microporous hollow carbon black of the present invention has a BET specific surface area of 180 to 1,200 m ² /g, preferably a BET specific surface area of 320 to 1,150 m ² /g, more preferably 450 to 820 m ² /g , and more preferably 490 to 750 m ² /g.

In addition, the microporous hollow carbon black of the present invention may have a total pore volume of 0.190 to 1.200 cm ³ /g, preferably a total pore volume of 0.300 to 0.950 cm ³ /g, more preferably It can satisfy the total pore volume of 0.500 ~ 0.800 cm ^{3 /g.}

And, the micropore hollow carbon black of the present invention may have an average particle diameter of the micropores of 4.0 to 8.0 nm, preferably 4.0 to 6.5 nm, more preferably 4.2 to 6.0 nm.

In addition, in the microporous hollow carbon black of the present invention, the fraction (V _micro /V _total X 100%) of the micropore volume (V _{micro ) relative to the total} pore volume (V total ) may be 4.0 to 13.6%, preferably For example, it may be 5.0 to 13.6%.

These, of the present invention Microporous hollow furnace carbon black can support various materials and has excellent electrical properties, so it can be used as a material in a wide variety of fields, for example, an electrocatalyst support for fuel cells, carbon support for secondary batteries, etc. .

Hereinafter, the present invention will be described in more detail based on examples. However, the scope of the present invention should not be construed as being limited by the following examples.

[Example]

Example 1: Preparation of microporous hollow furnace carbon black according to reaction time

Furnace carbon black (trade name: Super-P, manufacturer: IMERYS) was prepared as a raw material. The basic physical properties of the prepared furnace carbon black are shown in Table 1 below.

BET non-representative (m 2 /g)	Micro Pore volume (cm 3 /g)	total pore volume (cm 3 /g)	average pore size
61.4	0.01	0.165	10.8 nm

Next, after preheating the horizontal tubular furnace (oxidation chamber) shown in FIG. 2 to 1000° C., the raw material is charged into the reaction tube of the oxidation chamber using a quartz boat, and then fixed at 1000° C. A gas phase oxidation reaction was performed. _{An oxidizing gas containing CO 2} at a concentration of 99.950% by volume as a reactive substance was used, and the flow rate of the oxidizing gas was maintained at 100 ml/min using a ball flow meter. And, the reaction time is shown in Table 2 below, the yield (%), BET specific surface area (m ² /g), MV (micropore volume, cm ³ /) of the microporous hollow furnace carbon black prepared according to each reaction time g), the total pore volume (Total pore volume cm ³ /g), and the average pore size (nm) are shown in Table 2 below. In addition, a transmission electron microscope (TEM) measurement photograph for each of them is shown in FIGS. 3 to 6 .

Temperature (℃)	reaction time (minute)	burn-off yield (%)	BET non-representative (m 2 /g)	Micro pore volume (cm 3 /g)	gun pore volume (cm 3 /g)	average pore size (nm)
1,000	0	0	61.4	0.010	0.165	10.8
	10	7.2	102.3	0.024	0.176	9.5
	30	15.4	184.2	0.021	0.207	7.8
	55	30.4	334.6	0.037	0.273	5.5
	98	48.2	590.5	0.044	0.633	4.3
	115	59.9	788.1	0.060	0.766	5.9
	148	83.2	1,107.6	0.055	1.328	4.8

Referring to FIG. 3 , in the case of furnace carbon black that is not subjected to vapor phase oxidation treatment, no pores are observed inside and no pores are developed inside, so it can be seen that the ^{BET specific surface area is very small as 61.4 m 2 /g.} .

Referring to FIG. 3 , in the case of furnace carbon black subjected to vapor phase oxidation treatment for 10 minutes, it was observed that the crystallites inside were clouded, and it was confirmed that the micropore volume increased by about 2.4 times compared to the raw material furnace carbon black.

In addition, referring to FIGS. 4 and 5, in the case of furnace carbon black subjected to vapor phase oxidation treatment for 30 minutes, 55 minutes, and 98 minutes, it can be confirmed that internal pores are developed and the crystallinity of the wall surrounding the pores is increased. .

And, referring to FIG. 5 , in the case of furnace carbon black subjected to vapor phase oxidation treatment for 115 minutes, the wall surrounding the internal pores became rather thin and some slippage occurred. In addition, referring to FIG. 6 , in the case of furnace carbon black subjected to vapor phase oxidation treatment for 148 minutes, the BET specific surface area is increased by about 18 times compared to the raw material, and the pores are developed and grown (merged) to form primary particles of carbon black. collapse was observed. In addition, the furnace carbon black subjected to the gas phase oxidation treatment for 148 minutes had a problem that the burn-off yield was too high as 83.2%, so that the yield for the product was too low.

In addition, looking at Tables 2 and 3, as the gas phase oxidation reaction time increased, the BET specific surface area, micropore volume, and total pore volume tended to increase, but if the gas phase oxidation reaction was performed for too long, the pores were crushed and , there was a phenomenon of coalescence between the furnace blacks, and in order to secure appropriate physical properties and yield, an appropriate gas phase oxidation reaction time is 30 minutes to 150 minutes, preferably 40 minutes to 120 minutes, more preferably 45 minutes to 110 minutes. was able to confirm that

Example 2: Preparation of microporous hollow furnace carbon black according to reaction temperature

In the same manner as in Example 1, the furnace carbon black (raw material) was subjected to vapor phase oxidation, but by varying the oxidation treatment temperature as shown in Table 3 below, microporous hollow furnace carbon black was prepared, respectively. Physical properties of the prepared furnace carbon black was measured.

Temperature (℃)	reaction time (minute)	burn-off yield (%)	BET non-representative (m 2 /g)	Micro pore volume (cm 3 /g)	gun pore volume (cm 3 /g)	average pore size (nm)
800	98	23.8	217.2	0.027	0.249	6.9
880		32.3	360.6	0.039	0.298	5.1
950		43.3	500.1	0.041	0.591	4.8
1000		48.2	590.5	0.044	0.633	4.3
1150		61.8	790.8	0.063	0.798	5.7
1250		75.0	907.6	0.057	1.246	6.2

Looking at Table 3, it can be seen that as the reaction temperature increases, the burn-off yield increases, the BET specific surface area, micropore volume, and total pore volume increase, and the average pore size tends to decrease. In the case of 1250 ℃ exceeding 1200 ℃, compared with 1150 ℃, the burn-off yield increased sharply, but rather the average pore size increased, which resulted in a decrease in micro-pores and an increase in macro-pores. This is because, as a result, the total pore volume was significantly increased.

And, in the case of 800°C, where the reaction temperature is less than 850°C, there was a problem of having too low physical properties in terms of specific surface area and micropore volume.

Example 3: Preparation of microporous hollow furnace carbon black according to oxidizing gas flow rate

In the same manner as in Example 1, the furnace carbon black (raw material) was subjected to vapor phase oxidation, but as a reactive gas, CO ₂ (concentration of 99.950 vol%), which is an oxidizing gas, was changed as shown in Table 4 below, and microporous hollow furnace carbon black were prepared, respectively, and the physical properties of the prepared furnace carbon black were measured.

CO 2 flow (ml/min)	reaction time/ reaction Temperature	burn-off yield (%)	BET non-representative (m 2 /g)	Micro pore volume (cm 3 /g)	gun pore volume (cm 3 /g)	average pore size (nm)
45	98 minutes / 1000℃	32.3	307.5	0.031	0.457	5.3
80		46.5	580.1	0.042	0.621	4.5
100		48.2	590.5	0.044	0.633	4.3
120		48.9	598.1	0.047	0.665	4.1
180		55.1	620.9	0.059	0.952	5.3
210		63.8	841.7	0.065	1.118	5.9

Referring to Table 3, as the CO ₂ flow rate increased, the burn-off yield increased, and the BET specific surface area, micropore volume, and total pore volume tended to increase. However, when the CO ₂ flow rate was 45 ml/min, there was a problem that the yield was too low, and when the CO ₂ flow rate was 210 ml/min, the physical properties such as yield, specific surface area, micropore volume, and total pore volume were excellent, but the pores were too small It was large and formed a lot, so the strength was too weak and there was a problem that it was easily broken.

Through the above Examples and Experimental Examples, through the manufacturing method of the present invention, a hollow hollow structure furnace carbon black having micropores having a very high micropore volume, total pore volume and BET specific surface area than the raw material and having micropores in high yield. It was confirmed that it could be manufactured. As such, the microporous hollow furnace carbon black of the present invention can support various materials and has excellent electrical properties, so it is expected to be utilized as a material in a wide variety of fields.

Claims (10)

1. Step 1 of preparing furnace carbon black; and

   a second step of performing a gas phase oxidation reaction of the furnace carbon black using an oxidizing gas;

   A method for producing a microporous hollow carbon black comprising a.
2. The method according to claim 1, wherein the micropore volume of the furnace carbon black subjected to the two-step gas phase oxidation reaction satisfies the following equation;

   [Equation 1]

   2.0 ≤ B/A ≤ 7.0

   In Equation 1, A is the micropore volume of the furnace carbon black before the gas phase oxidation reaction is performed, and B is the micropore volume of the furnace carbon black subjected to the gas phase oxidation reaction.
3. According to claim 1, wherein the gas phase oxidation reaction is carried out in an oxidation chamber,

   A method for producing microporous hollow carbon black, characterized in that it is carried out for 30 minutes to 150 minutes while supplying an oxidizing gas under 850 to 1200° C.
4. According to claim 1, wherein the oxidizing gas comprises 99.000 ~ 99.999% by volume of CO ₂ ,

   The gas phase oxidation reaction is a method for producing microporous hollow carbon black, characterized in that it is performed while supplying an oxidizing gas at a rate of 50 to 200 mL/min.
5. A furnace carbon black prepared by gas phase oxidation reaction of furnace carbon black using an oxidizing gas, it has a hollow structure and has a number of micro-sized pores,

   Microporous hollow carbon black, characterized in that it has a micropore volume satisfying Equation 1 below;

   [Equation 1]

   2.0 ≤ B/A ≤ 7.0

   In Equation 1, A is the micropore volume of the furnace carbon black before the gas phase oxidation reaction is performed, and B is the micropore volume of the furnace carbon black subjected to the gas phase oxidation reaction.
6. The microporous hollow carbon black according to claim 5, wherein the BET specific surface area is 180 to 1,200 m ^{2 /g.}
7. [Claim 6] The microporous hollow carbon black according to claim 5, wherein the total pore volume is 0.190 to 1.200 cm ^{3 /g.}
8. [8] The microporous hollow carbon black according to any one of claims 5 to 7, wherein the average particle diameter of the micropores is 4.0 to 8.0 nm.
9. An electrocatalyst carrier for a fuel cell comprising the microporous hollow carbon black of any one of claims 5 to 7.
10. A carbon support for a secondary battery comprising the microporous hollow carbon black of any one of claims 5 to 7.

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