WO2006046756A1 - Porous carbon nitride material and method for preparation thereof - Google Patents

Abstract

[PROBLEMS] To provide a method, which allows the preparation of a porous carbon nitride material having a desired nitrogen content with ease and also can set a C/N value precisely over a wide range. [MEANS FOR SOLVING PROBLEMS] A method for preparing a porous carbon nitride material (MCN), which comprises a step of mixing a porous silica material, a nitrogen source and a carbon source, a step of heating the mixture obtained in the mixing step and a step of removing the porous silica material from a reaction product obtained in the heating step, wherein the heating step comprises a step of converting the mixture to a polymeric material at a first temperature and a step of carbonizing the mixture at a second temperature being higher than the first temperature.

Description

 Porous carbon nitride and method for producing the same

 The present invention relates to a carbon nitride porous body and a method for producing the same, and more specifically, a method for producing a carbon nitride porous body in which the ratio of carbon atoms to nitrogen atoms (CZN ratio) can be easily controlled, and The carbon nitride porous body obtained in this way. Background art

In recent years, porous bodies having nanoscale pores produced using various silica replicas have attracted attention. Among them, carbon-based porous materials containing nitrogen are expected to be used in various applications such as adsorbents, separating agents, single catalysts, battery electrodes, capacitors, and energy storage devices, and research is being actively conducted. . A method for producing a porous body in which adsorption characteristics are improved by a high specific surface area and a high nitrogen content has been proposed in patent literature (see, for example, patent literature 1). FIG. 10 is a flowchart showing a method for producing a nitrogen-containing carbon-based material according to the prior art. Each process will be described. _ Step S 1 100: Nitrogen-containing porous metal oxides (for example, porous materials composed of metal oxides and composite metal oxides, such as silica mesoporous materials, zeolites, crosslinked clays, etc.) By introducing an organic compound (for example, an organic compound containing a nitrogen atom, a nitrogen-containing bicyclic compound, an amine, an imine, a nitrile, etc.) and thermally decomposing the nitrogen-containing organic compound, A nitrogen-containing carbon-based material whose skeleton is formed by carbon and nitrogen atoms is deposited in the pores. Specifically, a metal oxide porous body is placed in the reaction tube, and heated to a predetermined temperature while introducing an inert gas such as nitrogen or argon into the reaction tube. Next, a nitrogen-containing organic compound in a gaseous state is introduced into the reaction tube while maintaining the heating state, thereby introducing the nitrogen-containing organic compound into the pores of the metal oxide porous body for a predetermined time. Perform the CVD reaction. As a result, a nitrogen-containing carbon-based material having a skeleton formed of carbon atoms and nitrogen atoms is deposited in the pores of the metal oxide porous body. Step S 1 2 0 0: A porous body made of a nitrogen-containing carbon-based material is obtained by dissolving and removing the metal oxide porous body. Specifically, the metal oxide porous body is chemically dissolved using hydrofluoric acid or alkali. As a result, a specific surface area of 600 m ² / g or more, an average pore diameter of 1 to 5 nm, and carbon atoms A nitrogen-containing carbon-based porous material having an atomic ratio of C to N (CZN) of 3.3 3 to 12.5 is obtained. References

 Patent Document 1: Japanese Unexamined Patent Application Publication No. 2004-1 68 58 7 Disclosure of Invention

 Problems to be solved by the invention

However, although the nitrogen-containing carbon-based porous material described in Patent Document 1 has a higher nitrogen content than the conventional homogeneous porous material, there is a limit in trying to increase the nitrogen content further. It was. For this reason, there were limits to the adjustment of various derived characteristics such as adsorption performance. That is, the method for producing a nitrogen-containing carbon-based porous material described in Patent Document 1 uses a single compound containing both components as a nitrogen source and a carbon source as raw materials, and uses this as a starting material. Therefore, the C / N ratio of the resulting product was determined by the starting material compound, and there were limits to increasing the nitrogen ratio and adjusting the CZN ratio to an arbitrary value. In addition, the method for producing a nitrogen-containing carbon-based porous material described in Patent Document 1 requires a large apparatus such as a CVD, so that the production cost is high and the control is complicated. Therefore, an inexpensive and easy production method for a nitrogen-containing carbon-based porous body that does not depend on such production means is desired. From the above, an object of the present invention is to provide a method for easily producing a carbon nitride porous body having an intended nitrogen content. The “carbon nitride” referred to in the present specification is not limited to a material having the chemical formula C ₃ N _4, and intends a material in which the ratio of nitrogen atoms to carbon atoms is represented by an arbitrary ratio. Means for solving the problem

The method for producing a carbon nitride porous body (MCN) according to the present invention includes a step of mixing a silica porous body, a nitrogen source, and a carbon source, a step of heating a mixture obtained by the mixing step, and the heating A step of removing the porous silica from the reaction product obtained by the step of producing a porous carbon nitride as described above. The porous silica material functions as a template. Specifically, pores selected from the group consisting of MCM-48, SBA-15, KIT-5, and SBA-1 are provided. A porous silica material having a structure communicating with each other can be mentioned and used. As the nitrogen source, it easily diffuses into the porous silica and is thermally decomposed to form nitride. Although it is not particularly limited as long as it can be produced, a nitrogen-containing compound such as amines or diaryls is preferable. More specifically, one or more selected from the group consisting of aliphatic amines, aromatic amines, ammonia, aliphatic nitriles, aromatic nitriles, nitrogen-containing heterocyclic compounds, and hydrazine are used. The The carbon source is not particularly limited as long as it can easily diffuse into the porous silica and can be pyrolyzed to produce a carbide, and preferably includes a halogenated hydrocarbon or a derivative thereof. As the octalogated hydrocarbon, one or more selected from the group consisting of chlorinated hydrocarbon, brominated hydrocarbon, and iodinated hydrocarbon are used. As the chlorinated hydrocarbon, one or more selected from the group consisting of carbon tetrachloride, black mouth form, methylene chloride, chloroform, and dichloromethane are used. Specific examples of the brominated hydrocarbon include carbon tetrabromide and bromoform. Specific examples of the iodinated hydrocarbon include iodomethane and iodinated tan. In the mixing step, the ratio (CZN) of carbon atoms (C) to nitrogen atoms (N) preferably satisfies the relationship 0.25≤CZN≤3.0. Preferably, the heating step may further include a step of polymerizing the mixture at a first temperature and a step of carbonizing the mixture at a second temperature higher than the first temperature. The polymerization step is preferably performed by heating the mixture at the first temperature for 1 hour to 6 hours, which is selected from a temperature range of 70 to 1550 in the atmosphere. The carbonizing step includes heating the mixture at a second temperature selected from a temperature range of 50.00 to 800 in a nitrogen atmosphere or an inert gas atmosphere for 4 to 8 hours. Is preferred. The removal process of the porous silica is performed by selectively dissolving the porous silica using hydrofluoric acid or an alkaline aqueous solution, and filtering and recovering the reaction product (nitrogen carbon porous body) as an insoluble residue. . A step of washing and drying the reaction product after the removing step may be further included. In the carbon nitride porous body (MCN) containing carbon atoms and nitrogen atoms according to the present invention, the ratio (C / N) of the carbon atoms (C) to the nitrogen atoms (N) has a relationship of 0.25≤C /N≤3.0 is satisfied, and the carbon atom and the nitrogen atom are a single bond or a double bond, thereby achieving the above object. The specific surface area of the MCN porous body is preferably 50 Om ^ / g or more from the viewpoint of improving adsorption characteristics. The pore diameter of the MCN porous body may be 4 nm or more and 10 nm or less. The invention's effect

 The method for producing a carbon nitride (MCN) porous body according to the present invention includes a step of mixing a silica porous body, a nitrogen source, and a carbon source, a step of heating a mixture obtained by the mixing step, and a step of heating Removing the porous silica from the reaction product obtained by the step. Since a nitrogen source and a carbon source are used separately as starting materials, the amount of nitrogen during charging can be easily controlled. As a result, the carbon nitride porous body obtained by the heating step can have an intended nitrogen content. In addition, a carbon nitride porous body having a desired shape, pore diameter, and specific surface area can be obtained by appropriately selecting a silica porous body as a replica. Since the carbon nitride porous body obtained in this way can contain a larger amount of nitrogen than before, the amount of adsorption can be improved. Brief Description of Drawings

 Fig. 1: Flow chart showing a method for producing a carbon nitride porous material (MCN) according to the present invention.

 Fig. 2: Schematic diagram of carbon nitride porous material (MCN) according to the present invention

 Figure 3: X-ray diffraction pattern of MCN (a) and S BA-1 5 (b) obtained in Example 1

 Figure 4: Electron micrographs (a) and (b) and elemental mapping (c) and (d) of MCN obtained in Example 1

 Fig. 5: Electron energy loss spectrum of MCN obtained in Example 1 Fig. 6: Nitrogen absorption of MCN complex (a) and SB A- 15 (b) obtained in Example 1 Diagram showing desorption isotherm

 Fig. 7: Diagram showing the pore size distribution of the MCN composite (a) and SBA-15 (b) obtained in Example 1

 Figure 8: MCN FT-IR spectrum obtained in Example 1

Fig. 9: XPS wide spectrum (a) of MCN obtained in Example 1, C ls spectrum (b) of MCN, and N ls spectrum (c) of MCN Flow chart showing a method for producing a nitrogen-carbon material Explanation of symbols

 2 0 0 Porous carbon nitride (M C N) Best mode for carrying out the invention

 Embodiments of the present invention will be described below with reference to the drawings.

 FIG. 1 is a flow chart showing a method for producing a carbon nitride porous material (M C N) according to the present invention. Each process will be described. Step S 1 1 0: A porous silica material, a nitrogen source and a carbon source are mixed.

The silica porous body means an arbitrary structure made of silica in which pore structures are connected three-dimensionally or two-dimensionally. For example, such a structure may have a hexagonal structure, a cubic structure, or an irregular structure. Here, the hexagonal structure is a hexagonal structure in which the pores in the porous silica material are arranged, and includes both a known two-dimensional hexagonal structure and a three-dimensional hexagonal structure. The cubic structure is a cubic structure in which the pores in the porous silica are arranged. Such a porous silica is preferably MCM-48 having a cubic structure, SBA-1, SBA-1 having a structure in which one-dimensional medium-sized pores are connected to fine pores, and pores. It can be selected from the group consisting of KITs with irregularly three-dimensionally connected structures. Note that the structure of the resulting carbon nitride porous body (MCN) depends on the structure of the selected silica porous body. Therefore, a carbon nitride porous body having a desired shape, pore diameter and specific surface area can be obtained by appropriately selecting a porous silica body. The silica porous body may be one kind or a combination of two or more kinds. The nitrogen source is a nitrogen-containing compound, and in particular, may be amines or nitriles. Such a nitrogen-containing compound is preferably at least one selected from the group consisting of aliphatic amines, aromatic amines, ammonia, aliphatic nitriles, aromatic nitriles, nitrogen-containing heterocyclic compounds, and hydrazine. Selected. The carbon source is a halogenated hydrocarbon or a derivative thereof. At least one such hydrogen halide is selected from the group consisting of chlorinated hydrocarbons, brominated hydrocarbons and iodinated hydrocarbons. Examples of the chlorohydrocarbon include, but are not limited to, carbon tetrachloride, black mouth form, methylene chloride, chloromethane, or dichloromethane. Brominated hydrocarbons include, but are not limited to, for example, carbon tetrabromide or promoform. Furthermore, the iodinated hydrocarbon can be, for example, iodomethane or iodinated tan, but is not limited thereto. Nitrogen and carbon sources can be adjusted so that the ratio of carbon atom (C) to nitrogen atom (N) (CZN) satisfies the relationship CZN≥0.25. When the C / N ratio was less than 0.25, a carbon nitride porous body could not be obtained. The CZN ratio can preferably be adjusted in the range of 0.2 5 ≤ C / N ≤ 3.0. Within this range, the composition is very close to that of C ₃ N ₄ type carbon nitride, and thus the obtained porous material can have ultra-high hardness and semiconducting properties. As described above, since the nitrogen source and the carbon source are used separately as starting materials, the CZN ratio can be controlled easily and with high accuracy. Step S 1 20: The mixture obtained in Step S 1 10 is heated. As a result, the mixture reacts and a carbon nitride porous body can be obtained. More specifically, the mixture is polymerized at a first temperature and then the mixture is carbonized at a second temperature that is higher than the first temperature. Polymerization is carried out by heating in the atmosphere at a first temperature selected from a temperature range of 70 to 150 for 1 to 4 hours. Any heating means such as a hot plate can be used for heating. By this heating, the nitrogen source in the mixture is polymerized, and the mixture containing the polymerized nitrogen source is refluxed. Next, the mixture is located in the pores of the porous silica material by stirring them. This gives a well-ordered carbon nitride porous body (MCN). Carbonization is performed by heating at a second temperature selected from a temperature range of 500 to 800 in a nitrogen atmosphere or an inert gas atmosphere for 4 to 8 hours. Any heating means such as an electric furnace can be used for heating. By this heating, the polymerized nitriding source is carbonized by the carbon source (that is, the nitrogen atom and the carbon atom are bonded by a double bond or a double bond). In this way, the reaction product obtained in the pores of the porous silica material is a carbon nitride porous material (MCN). Prior to carbonization, the polymer obtained by polymerization may be dried to form fine particles. Thereby, the carbonization time can be shortened. Step S 1 30: The obtained reaction product is removed from the porous silica material. By filtering the porous silica using hydrofluoric acid or alkaline aqueous solution, only the reactant MCN can be extracted. An arbitrary aqueous solution capable of dissolving the porous silica can be used. After step S 1 30, the extracted reactant may be washed and dried. For cleaning, pure water, distilled water, or ethanol is used. Drying can be done using any heating means such as a hot plate. According to the method for producing a carbon nitride porous body of the present invention, a nitrogen source and a carbon source are separately used as starting materials in step S 110. As a result, the amount of nitrogen at the time of charging can be controlled over a wide range (CZN ^ O. 2 5) and with higher accuracy. A carbon nitride porous body can be easily produced. FIG. 2 is a schematic view of a carbon nitride porous body (MCN) according to the present invention.

 The carbon nitride porous body (MCN) 200 is an example when S B A- 15 is used as the porous silica body in the method described with reference to FIG. The MCN 200 includes a pillar portion (indicated by a cylindrical bar piece in FIG. 2) and a bridge portion (indicated by a cylindrical small piece in FIG. 2) made of carbon nitride. It should be understood that the structure of MCN 200 depends on the selected silica porous material. The pillars are regularly arranged in a hexagonal shape when S B A— 15 is used. The bridges are much smaller than the pillars and connect the pillars together. Both the column part and the bridge part are made of carbon nitride.

In MCN 200, the pore diameter is intended to be the distance between the pillars. The pore size of MC N 200 according to the present invention is 4: 1111 to 1 01111. Since such a pore diameter corresponds to the diameter of various biological substances such as proteins, these biological substances can be immobilized in the MCN 200 pores. The specific surface area of MCN ²⁰⁰ is more than 500 m ² Zg, which can be advantageous for large-scale and delicate adsorption of external substances and substance sensing based thereon. The ratio (C / N) of carbon atom (C) to nitrogen atom (N) in MCN 20 0 is CZN≥0.25, preferably 0.225≤CZN≤3.0. Thus, MCN 200 obtained by the production method according to the present invention can increase the amount of nitrogen as compared with the conventional method, and thus has a large number of basic adsorption sites. As a result, excellent adsorptivity can be expected. In the carbon nitride porous body having the chemical formula C ₃ N ₄ , it can be used as a semiconductor or high-strength material, which is the original property of carbon nitride, as a substitute for semiconductor devices or industrial diamond. Next, the present invention will be described in detail using specific examples. However, it should be noted that the present invention is not limited to these examples. Example 1;

0.5 g of SBA-15 as a porous silica, 2.22 g of ethylenediamine as a nitrogen source, and 5.35 g of carbon tetrachloride as a carbon source were prepared and mixed. The mixture was refluxed and stirred in the atmosphere at 90 ° C. for 6 hours to polymerize. The polymer was dark brown. Next, the obtained polymer was dried for 12 hours to be powdered. The powder was heated to 6.00 at a heating rate of 3.0: Z while flowing nitrogen at 50 ml / min, and held at 600 at 5 hours for carbonization. After filtering SBA-15 using 5 wt% hydrofluoric acid, the reaction product (MCN) was washed several times with ethanol and dried at 10. The reaction product thus obtained was subjected to structural analysis using an X-ray diffractometer (Siemens D5005, Brucker AX S, UK). The operating conditions of the X-ray diffraction apparatus were 40 kV / 50 mA, scanning speed of 0.5 ° 20 minutes using Cu—Κα rays. The X-ray diffraction pattern of MCN was compared with the X-ray diffraction pattern of the porous silica (SBA-1 5 in Example 1). The reactants were observed using a high-resolution transmission electron microscope (J EOL-3100 F and JEOL-3100 FEF, JEOL, Japan). The obtained reaction product was made into particles using a mortar and dispersed on a holey carbon film located on a grid made of Cu to prepare a sample. The operating conditions of the transmission electron microscope were an acceleration voltage of 300 kV and a resolution of 150,000 to 120,000 times. In addition, energy loss spectroscopy was performed using these high-resolution transmission electron microscopes. At this time, elemental matbing was also performed at a resolution of 5 A using a standard 3-window procedure with a slit width of 20 eV. The analysis region where energy loss and element mapping were performed was a region with a diameter of 100 to 200 nm. Nitrogen adsorption / desorption isotherms were measured using a specific surface area / pore distribution measuring device (Au tosorb 1, Quantachrom, USA). Samples were measured at the 5 2 3 K at pressure 1 0- ⁵ h P a following 3 hours degassed after 7 7 K. By measuring the adsorption / desorption isotherm, the presence or absence of pores and the shape and size of the pores can be determined. The pore structure was analyzed using the B arrett-Jayner-Halenda method. Here, the MCN complex before removing SBA-15 (ie, the state where MCN is located in SBA-15) is used as a sample. The adsorption / desorption isotherm of the MCN complex was compared with the adsorption / desorption isotherm of SBA-15. Infrared absorption spectra were measured using a Fourier transform infrared spectrophotometer (Nicolet Nexus 6700, Thermo Electron, USA). The measurement wavelength region was from 400 cm- ¹ to 9500 cm- ¹ .

X-ray photoelectron spectroscopic analysis was performed using an X-ray photoelectron spectrometer (E s c a la ab 20 00, VG Sci entif i c, UK). The analysis area was about 30 m in diameter. The above results are shown in FIGS. 3 to 9 and described in detail.

 FIG. 3 is an X-ray diffraction pattern of MCN (a) and SBA-15 (b) obtained in Example 1.

In the X-ray diffraction pattern (a) of MCN, peaks corresponding to diffraction of (1 0 0), (1 1 0) and (2 0 0) of the two-dimensional hexagonal lattice (space group p 6 mm) were confirmed. . It was found from the diffraction peak (1 0 0) that the lattice constant a ₁₀₀ = 9.5 2 nm. The MCN X-ray diffraction pattern (a) was similar to the X-ray diffraction pattern (b) of SB A_15. In addition, when thermogravimetric measurement was performed on MCN in an oxygen atmosphere, it was confirmed that the residual SBA-15 was less than 1% by weight. Therefore, it was found that the MCN X-ray diffraction pattern (a) was not due to the diffraction of the remaining SBA-15 itself. As shown in the inset, the MCN showed a single broad diffraction peak at 25.8 °. From this diffraction angle, the interlayer distance d of MCN was found to be 3.42A. This value almost coincided with the interlayer distance d obtained with the non-porous carbon nitride sphere. This indicates that MCN is composed of dalaphen layers with carbon and nitrogen atoms arranged in an evening-bostratic (turbulent) form. From the above, it was shown that the obtained MCN reflects the periodically arranged pore structure of SBA_15. FIG. 4 shows electron micrographs (a) and (b) and element mappings (c) and (d) of the MCN obtained in Example 1. Fig. 4 (a) is a photograph observed from the [1 0 0] direction of MCN, and a striped pattern was confirmed. In Fig. 4 (a), bright stripes indicate pore walls and dark stripes indicate pores. The inset in Fig. 4 (a) is a Fourier-transform light diffraction pattern obtained from the image, and shows a one-dimensional array of spots along the [1 0 0] direction. This indicates that there are no crystals arranged along the axis of the empty channel. Figure 4 (b) is a cross-sectional view of the MCN (ie, a photograph observed from the direction perpendicular to the [1 0 0] direction). From Fig. 4 (b), it can be seen that the MCN porous bodies are arranged in the form of hexagonal crystals (ie, honeycomb). The inset in Fig. 4 (b) is the Fourier transform light diffraction pattern. From these, it can be seen that this is a hexagonal arrangement peculiar to the space group p 6 mm. Figures 4 (c) and 4 (d) show the elemental mapping of carbon (C) and nitrogen (N), respectively. Other elements were not detected. As a result, the obtained MCN was found to be composed of carbon atoms and nitrogen atoms without containing residual SBA-15 and impurities. FIG. 5 is a diagram showing an electron energy loss spectrum of MCN obtained in Example 1. The spectrum showed peaks at 2 84 eV and 40 1 eV. This These peaks suggest that there are carbon atoms (C k edge: absorption by carbon k-shell electrons) and nitrogen atoms (Nk edge: absorption by nitrogen k-shell electrons), respectively. Also, since the C k edge has a sharp peak shape, this indicates that the carbon k-shell electron (1 S electron) is excited into the empty antibonding 7Γ electron orbit (ie, , I s—electronic transition). This suggests that MCN has s ρ ² hybrid orbitals, and that the dalaphen layer described with reference to Fig. 3 exists. The ratio of carbon atom (C) to nitrogen atom (Ν) was calculated from the peak area and the elastic scattering probability of each element, and CZN = 4.3. FIG. 6 is a graph showing nitrogen adsorption / desorption isotherms of the MCN complex (a) and SBA-15 (b) obtained in Example 1.

The amount of nitrogen adsorbed by the MCN complex (a) decreased compared to the amount of nitrogen adsorbed by SBA-15 (b). This decrease corresponds to the deposited MCN. Hysteresis was confirmed in the isotherms of (a) and (b). The isotherm with such a shape was found to be type VI according to the IUP AC classification. That is, it suggests that mesopores (2-50 nm pores) exist in the MCN complex. However, the nitrogen adsorption due to capillary condensation observed at relative pressures of 0.65 to 0.8 in SBA-15 (b) is shifted to a lower relative pressure in MCN complex (a). Was. Specifically, the MCN complex (a) showed nitrogen adsorption due to capillary condensation at relative pressures of 0.40 to 0.85. This suggests that the pore size of the MC N composite is smaller than that of SBA-15. The specific surface area of MCN was determined from the isotherm of the obtained MCN complex (a) using the BET equation. As a result, the specific surface area of MCN was 50 5 m ² Zg. Thus, MCN having a specific surface area of 500 m ² Zg or more can be advantageous for large-scale and delicate adsorption of external substances and substance sensing based thereon. FIG. 7 is a graph showing the pore size distribution of the MCN composite (a) and SBA-15 (b) obtained in Example 1. Based on the isotherms (a) and (b) obtained in Fig. 6, the pore size distributions of MCN and SBA-15 were determined. The pore diameter was determined from the pore volume distribution seen in the hysteresis of isotherms (a) and (b).

MCN was found to have a center of pore size distribution at 4.2 nm. On the other hand, SBA-15 was found to have a pore size distribution stop at 7.1 nm. This indicates that the pore diameter of MCN is 1.2 nm larger than the wall thickness (3 nm) of SBA-15. This difference in pore diameter is due to the shrinkage of SBA-15 when the carbon nitride polymer filled in the pores of SBA-15 is treated at high temperature. Is caused by. Further, such a pore diameter can be changed according to the selected porous silica. Since the obtained pore size is similar to the size of high molecular weight biological molecules such as enzymes, it can be advantageous for selective immobilization of these substances. FIG. 8 shows the FT-IR spectrum of MCN obtained in Example 1. The spectrum showed three absorptions at 1 2 5 7. 3 cm-1 5 7 0. 7 cm ¹ and 3 4 1 2 c πΓ ¹ . The absorptions at 1 2 5 7. 3 cm- ¹ and 1 5 7 0.7.7 cm- ¹ are absorption by aromatic C 1 N stretching vibration and absorption by aromatic ring stretching vibration, respectively. On the other hand, the absorption of 3 4 1 2 cm- ¹ is due to the stretching vibration of the N—H group in the aromatic ring. Also, since there is no absorption peak in the vicinity of 2 200 cm- ¹ , it can be seen that there is no C≡N element in MCN. The above results were similar to the FT-IR spectrum obtained with non-porous carbon nitride. FIG. 9 shows the XPS wide spectrum (a) of MCN obtained in Example 1, the C ls spectrum (b) of MC N, and the N ls spectrum (c) of MCN. Spectrum (a) shows that mainly carbon, nitrogen, and trace amounts of oxygen are present in MCN. The spectrum (b) indicating C ls in spectrum (a) is 2 8 8. 7 e V, 2 8 6. 8 e V, 2 8 5. 2 e V, and 2 8 4. O e Divided into 4 peaks with V binding energy. The peak corresponding to the lowest energy of 2 8 4.0 eV is due to the pure graph eye 非晶 質 in the amorphous C—N matrix. The peak corresponding to 2 8 5. 2 e V is due to the sp ² hybrid orbital carbon atom bonded to the nitrogen atom in the aromatic structure. The peak corresponding to 2 8 6. 8 e V is due to the sp ³ hybrid orbital, and the peak corresponding to 2 8 8. 7 e V is the highest energy in the aromatic ring bonded to the NH ₂ group. due to carbon atoms in sp ² hybrid orbitals. On the other hand, the spectrum (c) indicating N ls in the spectrum (a) was divided into two peaks with binding energies of 39.78 eV and 400.2 eV. The peak corresponding to 4 0. 2 e V is due to the nitrogen atom bonded to three carbon atoms in the amorphous C _N matrix. The peak corresponding to 3 9 7. 8 e V is caused by the nitrogen atom sp ² mixed with the carbon atom. From the results in Fig. 8 and Fig. 9, it was found that the bonding state of carbon and nitrogen atoms on the surface of MCN was almost the same as that of non-porous carbon nitride material. In addition, the CZN ratio obtained from the peak area value of the XPS spectrum in Fig. 9 almost coincided with the value obtained from Fig. 3. Example 2;

 The same treatment as in Example 1 was carried out except that 2.81 g of ethylenediamine was used as the nitrogen source and 4.43 g of carbon tetrachloride was used as the carbon source. Table 1 shows the CZN ratio of the obtained MCN. Example 3;

 The same treatment as in Example 1 was performed, except that 2.35 g of ethylenediamine was used as the nitrogen source and 2.36 g of carbon tetrachloride was used as the carbon source. Table 1 shows the CZN ratio of the obtained MCN. Example 4;

 The same treatment as in Example 1 was carried out except that 3.48 g of ethylenediamine was used as the nitrogen source and 0.31 g of carbon tetrachloride was used as the carbon source. Table 1 shows the CZN ratio of the obtained MCN. Example 5;

 The same treatment as in Example 1 was performed, except that 2.50 g of hydrazine was used as the nitrogen source and 3.33 g of carbon tetrachloride was used as the carbon source. Table 1 shows the CZN ratio of the obtained MCN. Example 6;

 The same treatment as in Example 1 was performed, except that 3.50 g of hydrazine was used as the nitrogen source and 0.48 g of carbon tetrachloride was used as the carbon source. Table 1 shows the CZN ratio of the obtained MCN. table 1 :

Example. Nitrogen source Carbon source MCN C / N ratio

 1 Ethylenediamine (2.22 g) Carbon tetrachloride (5.35 g) 4.3

2 Ethylenediamine (2.81 g) Carbon tetrachloride (4.43 g) 2.8

3 Ethylenediamine (2.35 g) Carbon tetrachloride (2.36 g) 1.9

 4 Ethylenediamine (3.48 g) Carbon tetrachloride (0.31 g) 1.2

 5 Hydrazine (2.50g) Carbon tetrachloride (3.33g) 0.73

6 Hydrazine (3.50g) Carbon tetrachloride (0.48g) 0.27 As shown in Table 1, the C / N ratio could be controlled over a wide range. It was found that the pore diameters of the MCN obtained in this way correspond to the diameters of biological substances such as various proteins. Therefore, using the MCN obtained by the present invention, a biological substance having a predetermined diameter can be immobilized in the pores of MCN. Industrial applicability

As described above, according to the method of the present invention, since a nitrogen source and a carbon source are separately used as starting materials, a carbon nitride porous body in which the CZN ratio is controlled in a wide range and with higher accuracy is manufactured. can do. The carbon nitride porous body obtained in this way has an adsorptivity that surpasses the properties of the conventional porous body, and thus can replace the conventional porous body. Specifically, the carbon nitride porous body produced by the method according to the present invention is applicable to an adsorbent, a separating agent, a single catalyst, a battery electrode, a capacitor, and an energy storage body. Further, according to the method of the present invention, a carbon nitride porous body represented by the chemical formula C ₃ N ₄ having a hardness equal to or higher than that of diamond can be produced. This makes it possible to replace conventional industrial diamonds. Further, it may be used for a semiconductor device or a light emitting device utilizing the property of carbon nitride semiconductor. In addition, since the pore structure is suitable for immobilization of biological materials, it can be applied to bioreactors with excellent mechanical strength and high durability, and various biosensors based on semiconducting properties.

Claims

The scope of the claims I. A method for producing a carbon nitride porous body (MCN), the step of mixing a silica porous body, a nitrogen source and a carbon source, the step of heating the mixture obtained by the step of mixing, And a step of removing the porous silica from the reaction product obtained by the heating step. 2. The method according to claim 1, wherein the porous silica is selected from the group consisting of MCM-48, SBA-15, KIT_5, and S S-1. 3. The method according to claim 1, wherein the nitrogen source is a nitrogen-containing compound of amines or nitriles. 4. The nitrogen-containing compound is selected from the group consisting of aliphatic amines, aromatic amines, ammonia, aliphatic nitriles, aromatic nitriles, nitrogen-containing heterocyclic compounds, and hydrazine. How to describe. 5. The method according to claim 1, wherein the carbon source is a parogenated hydrocarbon or a derivative thereof. 6. The method of claim 5, wherein the halogenated hydrocarbon is selected from the group consisting of chlorinated hydrocarbons, brominated hydrocarbons, and fluorinated hydrocarbons. 7. The method of claim 6, wherein the chlorinated hydrocarbon is selected from the group consisting of carbon tetrachloride, black mouth form, methylene chloride, chloromethane, and dichloromethane.  8. The method of claim 6, wherein the brominated hydrocarbon is carbon tetrabromide or bromoform. 9. The method according to claim 6, wherein the iodinated hydrocarbon is iodomethane or iodinated tan. 1. The mixing step according to claim 1, wherein the ratio (CZN) of carbon atoms (C) to nitrogen atoms (Ν) satisfies the relationship 0.2 5 ≦ C / N ≦ 3.0. Method. II. The step of heating further includes the step of polymerizing the mixture at a first temperature and the step of carbonizing the mixture at a second temperature higher than the first temperature. The method according to 1. 1 2. The polymerization step is selected from the temperature range from 70 to 150 in the atmosphere. The method of claim 11, wherein the mixture is heated at the first temperature for 1 hour to 6 hours. 1 3. The carbonizing step is performed in a nitrogen atmosphere or an inert gas atmosphere at the second temperature selected from a temperature range of 50000 to 800, for 4 hours to 8 hours, and the mixture The method according to claim 1, wherein the method is heated. 1 4. The method according to claim 1, wherein in the removing step, the reaction product is filtered using hydrofluoric acid or an aqueous alkali solution. 1 5. The method according to claim 1, further comprising washing and drying the reactant after the removing step. 1 6. A carbon nitride porous body (MCN) containing carbon and nitrogen atoms, wherein the ratio (CZN) of the carbon atoms (C) to the nitrogen atoms (N) is Meets ≤C / N≤3.0,  The porous body in which the carbon atom and the nitrogen atom are single-bonded or double-bonded. 1 7. The porous body according to claim 16, wherein a specific surface area of the MCN porous body is 500 m ² Zg or more. 18. The porous body according to claim 16, wherein the pore size of the MC N porous body is 4 nm or more and 10 nm or less.