JP-7854690-B2 - Carbon materials, catalysts, dispersions, electrodes, batteries, and electrolysis apparatus

Inventors

• 坂本 圭亮
• 安井 健悟
• 白石 康浩
• 平井 隆之

Assignees

• ＤＩＣ株式会社
• 国立大学法人大阪大学

Dates

Publication Date

20260507

Application Date

20240321

Priority Date

20230406

Claims (12)

1. A porous powdered carbon material, It contains at least carbon, nitrogen, and bromine as constituent elements , and at least one metallic element selected from the group consisting of Fe, Co, Ni, Cu, and Zn. The bromine content, as measured by combustion ion chromatography, is 50 to 100,000 ppm by mass. The chlorine content, as measured by combustion ion chromatography, is between 0 and 30,000 ppm by mass. The Zn content, as measured by inductively coupled plasma atomic emission spectroscopy, is 1 to 60,000 ppm by mass. The number of carbon atoms C xps and the number of nitrogen atoms N xps , as quantified by X-ray photoelectron spectroscopy, satisfy the condition 0.005 ≤ N xps / C xps ≤ 0.300. In the N1s spectrum measured by X-ray photoelectron spectroscopy, the peak intensity I1 at 398.5 ± 0.5 eV and the peak intensity I2 at 401.2 ± 0.5 eV satisfy 0.7 ≤ I2 / I1 ≤ 3.0. The number of carbon atoms (C CHN) and the number of nitrogen atoms (N CHN) , quantified by elemental analysis of CHN using the combustion method , satisfy the condition 0.005 ≤ N CHN / C CHN ≤ 0.300. [N XPS / C XPS ] / [N CHN / C CHN ] is 0.7 or higher, The specific surface area measured by the BET single-point method is 100 to 2000 m² /g. It has micropores with a pore diameter of less than 2 nm and mesopores with a pore diameter of 2 to 50 nm. The total volume of the micropores, as measured by the nitrogen gas adsorption method, is 0.03 to 3.00 cm³ /g. A carbon material having a total volume of mesopores measured by nitrogen gas adsorption, which is 0.3 to 4.0 cm³ /g .
2. The carbon material according to claim 1, wherein the total content of the metal element, as measured by inductively coupled plasma atomic emission spectroscopy, is 0.005 to 20% by mass.
3. The carbon material according to claim 1, wherein the Fe element content, as measured by inductively coupled plasma atomic emission spectroscopy, is 1 to 60,000 ppm by mass.
4. The carbon material according to claim 1, wherein the conductivity is 0.01 to 50 S/cm.
5. It is a calcined product of a raw material containing a phthalocyanine compound having bromine as a substituent, The carbon material according to claim 1, wherein the phthalocyanine compound contains Zn as the central metal.
6. The carbon material according to claim 5 , wherein the raw material further contains a compound comprising at least one metal element selected from the group consisting of Fe, Co, Ni, Cu, Al, and Zn.
7. A catalyst comprising the carbon material described in any one of claims 1 to 6 .
8. A dispersion comprising a carbon material according to any one of claims 1 to 6 and a dispersion medium for the carbon material.
9. The dispersion according to claim 8 , comprising a polymer electrolyte.
10. An electrode comprising an electrode catalyst layer containing the carbon material described in any one of claims 1 to 6 .
11. A battery comprising the electrode described in claim 10 .
12. An electrolysis apparatus comprising the electrodes described in claim 10 .

Description

This disclosure relates to carbon materials, catalysts, dispersions, electrodes, batteries, and electrolysis apparatus. Carbon materials are used in a wide range of applications due to their properties such as high electrical conductivity, high thermal conductivity, low thermal expansion coefficient, lightness, and heat resistance. In recent years, the use of nitrogen-containing carbon materials as catalysts (oxygen reduction catalysts) for the positive electrodes of fuel cells and air batteries has been investigated (see Patent Document 1). Furthermore, nitrogen-containing carbon materials may possess carbon dioxide reduction activity or nitrogen reduction activity, and are attracting attention as catalysts (carbon dioxide reduction catalysts or nitrogen reduction catalysts) for the cathodes of electrolysis devices (see Non-Patent Documents 1 and 2). Japanese Patent Publication No. 2012-101155International Publication No. 2021/220495 Angew. Chem. Int. Ed. , 2015, 54, 10758-10762Nature Communications, 2019, 10, 341-348 In this specification, numerical ranges indicated using "~" represent a range that includes the numbers before and after "~" as the minimum and maximum values, respectively. Furthermore, unless otherwise explicitly stated, the units of the numbers before and after "~" are the same. In numerical ranges described in stages within this specification, the upper or lower limit of one stage of the range may be replaced with the upper or lower limit of another stage. Also, in numerical ranges described within this specification, the upper or lower limit of that range may be replaced with the values shown in the examples (experimental examples). Furthermore, individually described upper and lower limits can be combined in any way. Preferred embodiments of this disclosure are described below. However, this disclosure is not limited to the embodiments described below. (Carbon materials) One embodiment of the present disclosure is a carbon material containing at least carbon (C), nitrogen (N), and bromine (Br) as constituent elements, wherein the bromine content, as measured by combustion ion chromatography (CIC), is 50 to 100,000 ppm by mass, and the number of carbon atoms (C xps) and the number of nitrogen atoms (N xps) , as quantified by X-ray photoelectron spectroscopy (XPS), satisfy the ratio 0.005 ≤ N xps / C xps ≤ 0.300. Specific methods for measuring the bromine content and elemental composition ratio N xps / C xps are described in the Examples (Experimental Examples). In this specification, N xps /C xps refers to the ratio of the number of carbon atoms C xps and the number of nitrogen atoms N xps , as quantified by XPS. The above carbon material exhibits excellent oxygen reduction activity and can therefore be used as a catalyst for oxygen reduction reactions (oxygen reduction catalyst). For example, it can be used as an electrode catalyst, such as a positive electrode catalyst for fuel cells and air batteries, or a cathode catalyst for oxygen electrolysis devices. The above carbon material also tends to exhibit carbon dioxide reduction activity and nitrogen reduction activity. Therefore, the above carbon material may also be usable as a catalyst for carbon dioxide reduction reactions (carbon dioxide reduction catalyst) and a catalyst for nitrogen reduction reactions (nitrogen reduction catalyst). Specific applications include, for example, cathode catalysts for carbon dioxide electrolysis devices and nitrogen electrolysis devices. The oxygen reduction activity, carbon dioxide reduction activity, and nitrogen reduction activity of the carbon material can be confirmed by the method described in the Examples (Experimental Examples). Carbon materials are materials that primarily contain carbon (C), with a carbon content of 60% by mass or more. The carbon content in the carbon material can be measured by CHN elemental analysis using the combustion method. The carbon content in the carbon material may be 70% by mass or more, or 80% by mass or more. The above bromine content may be 500 ppm by mass or more or 2000 ppm by mass or more, or 50,000 ppm by mass or less or 20,000 ppm by mass or less, from the viewpoint of obtaining better oxygen reduction activity. From the viewpoint of obtaining better oxygen reduction activity, the N xps /C xps ratio may be 0.010 or higher or 0.050 or higher, or 0.220 or lower or 0.140 or lower. In the N1s spectrum measured by the above XPS, the peak intensity I1 at 398.5 ± 0.5 eV and the peak intensity I2 at 401.2 ± 0.5 eV may satisfy the condition 0.7 ≤ I2 / I1 ≤ 3.0. In this case, superior oxygen reduction activity tends to be obtained. The reason for this is presumed to be as follows: First, in the above N1s spectrum, the peak located at 398.5 ± 0.5 eV is attributed to pyridine-type nitrogen, and the peak located at 401.2 ± 0.5 eV is attributed to quaternary-type nitrogen. Therefore, the intensity ratio of the two peaks corresponds to the ratio of the amount of quater