JP2010030844A - Method for manufacturing carbon nitride porous material (mcn) - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a carbon nitride porous material having controlled pore diameters, specific surface areas and specific pore volumes. <P>SOLUTION: The method for manufacturing a carbon nitride porous material (MCN) includes steps of: polymerizing a silica porous material SBA-15 with a mixture of ethylene, diamine and carbon tetrachloride, wherein the SBA-15 is subjected to a hydrothermal treatment at a temperature of 1×10<SP>2</SP>°C to 1.5×10<SP>2</SP>°C; carbonizing the polymeric material obtained by the polymerization step; and removing the silica porous material from the composite material obtained by the carbonization step. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a carbon nitride porous body, more specifically, carbonizing a polymer obtained by mixing a porous silica SBA-15 having a space group p6 mm and a raw material containing nitrogen and carbon to polymerize. Then, the present invention relates to a carbon nitride porous body (MCN) manufacturing method for removing the silica porous body, and to a carbon nitride porous body manufacturing method using silica porous body SBA-15 as a template.

  In recent years, porous bodies having nanoscale pores produced using various silica replicas have attracted attention. Among them, carbon-based porous bodies containing nitrogen are expected to be used in various applications such as adsorbents, separating agents, catalyst single bodies, battery electrodes, capacitors, energy storage bodies, and the like, and researches are being actively conducted.

  The inventor of the present application has developed a method for producing a porous carbon nitride using SBA-15 (see, for example, Patent Document 1). According to Patent Document 1, although a carbon nitride porous body having a high nitrogen content can be obtained, a carbon nitride porous body in which the pore diameter, specific surface area, and specific pore volume are controlled according to the application has not been obtained.

JP 2006-124250 A

Accordingly, an object of the present invention is to provide a method for producing a carbon nitride porous body having controlled pore diameter, specific surface area and specific pore volume. In this specification, “carbon nitride” is not limited to a material having a chemical formula of C ₃ N ₄ , and a material having an arbitrary chemical formula composed of a nitrogen atom and a carbon atom is intended.

In the method for producing a carbon nitride porous body (MCN) of the invention 1, the silica porous body SBA-15 to be used has a space group p6 mm by hydrothermal treatment, and the hydrothermal treatment temperature is selected within a range having the space group p6 mm. The pore diameter, specific surface area and specific pore volume are adjusted.
Invention 2 is characterized in that, in the method for producing a carbon nitride porous body (MCN) of Invention 1, the hydrothermal treatment temperature is selected in the range of 1 × 10 ² ° C to 1.5 × 10 ² ° C.
Invention 31 is characterized in that in the method for producing a porous carbon nitride (MCN) of Invention 1 or 2, the raw materials are ethylenediamine and carbon tetrachloride.
Invention 4 is characterized in that, in the method of Invention 3, the mass ratio of ethylenediamine and carbon tetrachloride in the raw material is 0.3 or more and 0.9 or less.

According to the present invention, the unit cell constant, the specific surface area, the specific pore volume, and the pore diameter of the carbon nitride porous body can be manufactured to desired values within the following ranges, respectively.
Unit cell constants 9.5Nm～10.5Nm, specific surface area ^{5 × 10 2 m 2 /g~8.3×10 2} m 2 / g, Hiana capacity 0.55cm ³ /g~1.25cm ³ / g and Pore diameter 4.0nm-6.5nm

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a flowchart showing a method for producing a carbon nitride porous body (MCN) according to the present invention. Each process will be described.

  Step S110: Polymerize a mixture of porous silica SBA-15, ethylenediamine (EDA), and carbon tetrachloride (CTC).

  Polymerization is performed by heating in the air at a temperature range selected from a temperature range of 70 ° C to 150 ° C for 1 hour to 6 hours. Arbitrary heating means such as a hot plate can be used for heating. By this heating, EDA is polymerized in the mixture, and the mixture containing the polymerized EDA is refluxed to obtain a polymer. Then, the mixture is located in the pores of SBA-15 by stirring them. As a result, a well-aligned carbon nitride porous body (MCN) can be obtained.

SBA-15 has a structure in which one-dimensional medium-sized pores are connected to each other with fine pores. SBA-15 used in the present invention is hydrothermally treated at a temperature of 1 × 10 ² ° C. or more and 1.5 × 10 ² ° C. or less. As a result, SBA-15 hydrothermally treated at a temperature of 1 × 10 ² ° C. to 1.5 × 10 ² ° C. has a space group of p6 mm, a unit cell constant in the range of 10.30 nm to 10.83 nm, 3 .9 × ¹⁰ 2 ^m 2 / g~9 specific surface area of × ¹⁰ 2 ^m 2 / ^g, a pore size of specific pore volume and 9.00~11.2nm of 1.1cm ³ /g~1.2cm 3 / g Have.

If such SBA-15 is used, the carbon nitride porous body (MCN) which has space group p6mm will be obtained reliably. In addition, if SBA-15 is hydrothermally treated in the above temperature range, it has a wide range of characteristics with respect to unit cell constant, specific surface area, specific pore volume and pore size, and thus the obtained MCN also has a wide range reflecting these. It can have the following characteristics. For example, when SBA-15 hydrothermally treated at high temperature is used, MCN having a large pore diameter is obtained, and when SBA-15 hydrothermally treated at low temperature is used, MCN having a small pore diameter is obtained. It is done. More specifically, the unit lattice constants 9.5Nm～10.5Nm, specific surface area ^{5 × 10 2 m 2 /g~8.3×10 2} m 2 / g, Hiana volume 0.55 cm ³ / g to 1. A carbon nitride porous body that can be controlled within a range of 25 cm ³ / g and a pore diameter of 4.0 nm to 6.5 nm can be obtained. Thus, it is preferable that MCN having desired characteristics can be obtained by appropriately selecting SBA-15 that has been hydrothermally treated in the above temperature range, because design according to the application becomes possible.

  More preferably, the weight ratio between EDA and CTC is adjusted to be 0.3 or more and 0.9 or less. If it is this range, MCN which maintained the structural orientation of SBA-15 and whose nitrogen content was controlled will be obtained. When the weight ratio of EDA and CTC is less than 0.3, the polymerization described later may be insufficient and MCN may not be obtained. On the other hand, if the weight ratio of EDA and CTC exceeds 0.9, a gel-like material may be obtained and the target MCN may not be obtained.

For example, the smaller the weight ratio between EDA and CTC, the smaller the unit cell constant, the interplanar spacing, and the pore diameter, and the larger specific pore volume and nitrogen content, and the larger the weight ratio, the larger the MCN. An MCN having a unit cell constant, interplanar spacing and pore size, and a small specific pore volume and nitrogen content is obtained. On the other hand, MCN having the largest specific surface area (about 8.2 × 10 ² m ² / g) is obtained when the weight ratio of EDA to CTC is 0.45, and the weight ratio of EDA to CTC is 0.45. The specific surface area decreases at the border. More specifically, the unit lattice constants 9.5Nm～11.5Nm, specific surface area ^{5.5 × 10 2 m 2 /g~8.2×10 2} m 2 / g, Hiana volume 0.7 cm ³ / g to A carbon nitride porous body that can be controlled within a range of 1.5 cm ³ / g, a pore diameter of 3.2 nm to 5.7 nm, and a nitrogen content (ratio of carbon atoms to nitrogen atoms) of 3.3 to 4.3 is obtained. be able to. Thus, MCN having desired characteristics can be obtained by adjusting the weight ratio of EDA and CTC in addition to the hydrothermal treatment temperature of SBA-15.

Step S120: The polymer obtained in Step S110 is carbonized. Carbonization is performed by heating in a temperature range selected from a temperature range of 5 × 10 ² to 8 × 10 ² ° C for 4 to 8 hours in a nitrogen atmosphere or an inert gas atmosphere. Arbitrary heating means such as an electric furnace can be used for heating. By this heating, the polymerized EDA is carbonized by CTC. Thus, the reaction product obtained in the pores of SBA-15 is a carbon nitride porous body (MCN). In addition, before carbonization, the polymer may be dried to form fine particles. Thereby, the carbonization time can be shortened.

  Step S130: The porous silica SBA-15 is removed from the carbide obtained in Step S120. By filtering SBA-15 using hydrofluoric acid or an aqueous alkali solution, only the product MCN can be extracted. In addition, arbitrary alkaline aqueous solutions which can dissolve SBA-15 can be used.

  After step S130, the extracted product may be washed and dried. For cleaning, pure water, distilled water, or ethanol is used. Drying may be performed using any heating means such as a hot plate.

In addition, the silica porous body SBA-15 used in step S110 is manufactured by the following procedure. Polyethylene glycol-block-polypropylene glycol-block-polyethylene glycol (Pluronic P123, molecular weight = 5800, EO ₂₀ PO ₂₀ EO ₂₀ ) amphiphilic triblock copolymer, acid and silicon source are mixed and stirred, and the gel is stirred. obtain. The acid is, for example, hydrochloric acid, and the silicon source is, for example, tetraethylorthosilicate (TEOS), but is not limited thereto.

The gel is hydrothermally treated in a temperature range of 1 × 10 ² ° C to 1.5 × 10 ² ° C and reacted. The reaction time is 10 to 24 hours. SBA-15 is obtained by calcining the reactant in the atmosphere at 540 ° C. and decomposing the triblock copolymer.

  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 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. The pillars are regularly arranged in a hexagonal shape. The bridging portion is extremely small as compared with the pillar portion, and joins the pillar portions to each other. Both of the column part and the bridge part are made of carbon nitride. In MCN200, a hole diameter intends the distance between pillar parts. The pore diameter of MCN200 according to the present invention is 3.2 nm to 6.5 nm when the above method is adopted. Such pore diameters correspond to the diameters of various organic substances, biological substances such as proteins, vitamins, amino acids and the like, and therefore these substances can be immobilized in the MCN200 mesopores. The specific surface area of MCN200 has a range of ^{5 × 10 2 m 2 /g~8.3×10 2} m 2 / g, can be advantageous in a large amount and delicate adsorption or substance sensing based thereon external substances .

  The present invention will now be described in detail using specific examples, but it should be noted that the present invention is not limited to these examples.

A porous silica SBA-15 as a template was produced. Disperse amphiphilic triblock copolymer (4 g) of polyethylene glycol-block-polypropylene glycol-block-polyethylene glycol (Pluronic P123, molecular weight = 5800, EO ₂₀ PO ₂₀ EO ₂₀ , Aldrich) in aqueous hydrochloric acid (120 mL, 2M) And stirred for 5 hours.

  Thereafter, tetraethylorthosilicate (TEOS, 9 g) was added and stirred to obtain a gel. The gel was aged at 40 ° C. for 24 hours, and then hydrothermally treated at 100 ° C., 130 ° C. and 150 ° C. for 24 hours to be reacted. After the hydrothermal treatment and reaction, each reaction product obtained was fired at 540 ° C. in the atmosphere to decompose the triblock copolymer. SBA-15 thus obtained is referred to as SBA-15-T (T = 100, 130 and 150). T represents hydrothermal treatment / reaction temperature.

  SBA-15-T was subjected to powder X-ray diffraction using a Rigaku diffractometer. CuKα radiation (λ = 0.154 nm) was used as the radiation source, and a range of 2θ = 0.8 ° to 8 ° was measured at a step time of 1 second. The measurement results are shown in FIG.

  FIG. 3 is a diagram showing XRD patterns of SBA-15-T (T = 100, 130, and 150) according to Example 1.

  All XRD patterns showed three distinct diffraction peaks. The diffraction peaks were indexed as (100), (110) and (200) from the low angle side, respectively. From this, it was confirmed that the obtained SBA-15-T is a two-dimensional hexagonal lattice (p6 mm). It was also found that the diffraction peak shifted to the lower angle side as the hydrothermal treatment temperature increased. This indicates that the interplanar spacing d and the unit cell constant are increasing. Furthermore, it was found that the relative strength of (110) increases and the relative strength of (200) decreases as the hydrothermal treatment temperature increases. In particular, the higher relative strength of (110) of SBA-15-150 suggests that the wall thickness of SBA-15-150 is thinner than the other SBA-15-100 and 130. Table 1 shows unit cell constants calculated from the XRD pattern of FIG.

  For SBA-15-T, a nitrogen adsorption / desorption isotherm (not shown) was measured using a specific surface area / pore distribution measuring device (Autosorb 1, Quantachrome, USA). The pore diameter distribution was calculated by the Barrett-Joyner-Halenda method, the specific surface area and the pore volume were calculated by the Brunauer-Emmett-Teller (BET) method. These results are summarized in Table 1.

  Table 1 shows that the unit cell constant and the pore diameter increase and the specific surface area decrease as the hydrothermal treatment temperature increases.

  Next, a porous carbon nitride (MCN) was produced using the porous silica of Example 1 as a template.

  FIG. 4 is a diagram showing a procedure for manufacturing a carbon nitride porous body.

  The procedure for manufacturing the MCN will be described with reference to FIG. SBA-15-100 (0.5 g) obtained in Example 1, ethylenediamine (EDA, 1.35 g, manufactured by Aldrich) and carbon tetrachloride (CTC, 3 g, manufactured by Aldrich) were mixed, and the mixture ( Gel). Here, the weight ratio of EDA and CTC in the gel was 0.45.

  The mixture was refluxed and stirred at 90 ° C. for 6 hours to polymerize. The resulting polymer was dark brown. The polymer was dried in an oven for 12 hours and powdered. Next, the powdered polymer was heated to 600 ° C. at a temperature rising rate of 3 ° C./min while flowing nitrogen at 50 mL / min, and kept at 600 ° C. for 5 hours to be carbonized.

  The obtained carbide (composite) was dissolved in hydrofluoric acid (5 wt%) to remove residual SBA-15-100 and filtered. The obtained sample was washed several times with ethanol and dried at 100 ° C. The MCN thus obtained is referred to as MCN-1-100 (or MCN-1-100-0.45).

  X-ray powder diffraction (XRD) was performed on MCN-1-100. CuKα radiation (λ = 0.154 nm) was used as the radiation source, and the range of 2θ = 0.8 ° to 10 ° and the range of 2θ = 10 ° to 80 ° were measured at a step time of 1 second. The measurement results are shown in FIGS. 5 and 6 and will be described later.

  About MCN-1-100, the nitrogen adsorption-desorption isotherm was measured using the specific surface area and pore distribution measuring apparatus (Autosorb 1, Quantachrome, USA). The sample was degassed at 250 ° C. for 3 hours and then measured at −196 ° C. The results are shown in FIG. 8 and will be described later. Moreover, the pore size distribution was calculated | required from the adsorption | suction branch of the adsorption / desorption isotherm using Barrett-Joyner-Halenda method. The results are shown in FIG. 9 and will be described later. Furthermore, the specific surface area was calculated from the nitrogen adsorption / desorption isotherm using the Brunauer-Emmett-Teller (BET) method. These results are summarized in Table 3.

  The surface morphology of MCN-1-100 was observed using a high resolution scanning electron microscope (HRSEM, Hitachi S-4800). The acceleration voltage at the time of observation was 5.0 kV. The observation results are shown in FIG.

  MCN-1-100 was subjected to energy loss (EEL) and elemental analysis using a Gatan-766 energy loss spectrophotometer and a Yanaco MT-5 CHN analyzer. The results are shown in FIG. 15 and Table 4 and will be described later.

  MCN-1-100 was subjected to X-ray photoelectron spectroscopy (XPS) using an X-ray photoelectron spectrometer (PHI-5400) equipped with a 200 W Mg Kα probe beam. Prior to measurement, the sample was exposed to high vacuum and placed in the analysis chamber. The measurement was performed with a pass energy of 20 eV, and C1s and N1s spectra were recorded. Each spectral region was repeatedly measured until a good signal-to-noise ratio was obtained. The results are shown in FIG.

About MCN-1-100, the infrared absorption spectrum (FT-IR) was measured using the Fourier-transform infrared spectrophotometer (Nicolet Nexus 670). Measurements employs a KBr pellet method, in the measurement wavelength range ^{4000cm -1 ~950cm} -1, resolution ^{2 cm -1,} an average of 200 scans were done in transparent mode. The spectrophotometer chamber was continuously purged with dry air to remove water vapor. The results are shown in FIG.

  The UV-vis absorption spectrum was measured for MCN-1-100. The measurement results are shown in FIG. 20 and will be described later.

  Since it is the same as that of Example 2 except having employ | adopted SBA-15-130 obtained in Example 1 as a template, description is abbreviate | omitted. Similar to Example 2, the weight ratio of EDA to CTC in the gel was 0.45. The MCN thus obtained is referred to as MCN-1-130 (or MCN-1-130-0.45).

  For MCN-1-130, XRD, specific surface area / pore distribution measurement, HRSEM, EEL, XPS and FT-IR spectrum were measured in the same manner as in Example 2. These measurement results are shown in FIGS. 5, 6, 8, 9, 11, 11, 15, 17, 19, 3, and 4, and will be described later.

  Further, MCN-1-130 was observed using a high-resolution transmission electron microscope (HRTEM, JEOL-3000F and JEOL-3100FEF) equipped with a Gatan-766 energy loss spectrophotometer. MCN-1-130 sonicated in ethanol for 2 to 5 minutes was deposited on a Cu grid to obtain a measurement sample. The acceleration voltage at the time of measurement was 200 kV. The observation results are shown in FIG.

For MCN-1-130, a ¹³ C NMR spectrum was measured using a Bruker spectrophotometer. A ¹³ C spectrum was obtained using a dipole decoupling magic angle rotation with an operating frequency of 75.49 MHz. Tetramethylsilane (TMS) was used as a reference. The results are shown in FIG. 21 and will be described later.

  The catalytic activity of MCN-1-130 (−0.45) was examined. Friedel-Crafts acylation reaction of benzene was performed using hexanoyl chloride as an acylating agent and heptane as a solvent. Specifically, a mixture of benzene (150 mg), hexanoyl chloride (50 mg) and MCN (25 mg) in heptane (5 g) was stirred at 90 ° C. for 20 hours. The obtained product was analyzed by gas chromatography (GC-2010 manufactured by Shimadzu). The results are shown in Table 7 and described in detail.

  Since it is the same as that of Example 2 except having employ | adopted SBA-15-150 obtained in Example 1 as a template, description is abbreviate | omitted. Similar to Example 2, the weight ratio of EDA to CTC in the gel was 0.45. The MCN thus obtained is referred to as MCN-1-150 (or MCN-1-150-0.45).

For MCN-1-150, XRD, specific surface area / pore distribution measurement, HRSEM, EEL, XPS, FT-IR spectrum, HRTEM and ¹³ C spectrum were measured in the same manner as in Example 3. The results are shown in FIGS. 5, 6, 8, 9, 12, 14, 15, 18, 19, 19, 21, 3 and 4 and will be described later.

  The experimental conditions of Examples 2 to 4 are summarized in Table 2.

  FIG. 5 is a diagram illustrating XRD patterns on the low-angle side of the MCNs of Examples 2 to 4.

  Comparing the XRD pattern of FIG. 5 with the XRD pattern of FIG. 3, it was found that the position and quality of the main peak were different. Specifically, the XRD patterns of MCN-1-100 and MCN-1-130 show three distinct diffraction peaks indexed at (100), (110) and (200), and the template SBA-15 There was good agreement with the XRD patterns of -100 and SBA-15-130. From this, it was shown that MCN-1-100 and MCN-1-130 are highly oriented two-dimensional hexagonal porous bodies even after removing the template, and the space group is p6 mm. That is, MCN-1-100 and MCN-1-130 have a structure in which cylindrical holes connected by micropores existing in the wall are arranged in a hexagonal crystal as schematically shown in FIG.

  On the other hand, the XRD pattern of MCN-1-150 showed only a sharp (100) peak and a weak (110) peak. As shown in Table 1, it is considered that the higher order diffraction of the obtained MCN-1-150 is impaired in the XRD pattern due to the increase in the pore size of the template SBA-15-150. It is done.

  Furthermore, the intensity of the (110) peak of MCN-1-150 is much lower compared to that of other MCN-1-100 and MCN-1-130. This is because there is a portion where MCN does not exist because SBA-15-150 having a large pore diameter is insufficiently filled with EDA and CTC. Therefore, the peak intensity decreases due to the interference of X-ray diffraction between the inside and outside of the MCN. However, since the (100) peak of MCN-1-150 is sharp and clear, it can be analogized that SBA-15-150 of the template maintains the structural orientation.

Next, as the pore size of the template increased (that is, the hydrothermal treatment temperature increased), the MCN diffraction peak obtained shifted to the lower angle side. That is, it was found that as the template having a higher hydrothermal treatment temperature was used, the interplanar spacing d and unit cell constant a _{0 of} the obtained MCN increased (Table 3). More specifically, the unit cell constants a ₀ of MCN-1-100, MCN-1-130, and MCN-1-150 were calculated to be 9.52 nm, 10.18 nm, and 10.50 nm, respectively.

  FIG. 6 is a diagram showing XRD patterns on the high angle side of MCNs of Examples 2 to 4.

  All MCNs showed a single broad diffraction peak on the high angle side, that is, around 25.8 °, in addition to the diffraction peak on the low angle side. This diffraction peak corresponds to an intermediate phase having an interplanar spacing d of 3.42 mm, and coincides with the interplanar spacing d obtained with a non-porous carbon nitride sphere. From this, the wall structure of the obtained MCN was considered.

  FIG. 7 is a schematic view of an MCN wall structure according to the present invention.

  From the XRD patterns of FIGS. 5 and 6, the MCN obtained according to the present invention has nitrogen atoms uniformly dispersed, and a graphene layer has a turbulent arrangement of carbon atoms and nitrogen atoms, as shown in FIG. It was found to have a unique wall structure.

  FIG. 8 is a diagram showing nitrogen adsorption / desorption isotherms of MCNs of Examples 2 to 4.

  FIG. 9 is a diagram showing a BJH pore size distribution of each MCN of Examples 2 to 4.

  Table 3 shows the unit cell constant, specific surface area, specific pore volume and pore diameter calculated from FIGS. 5, 8 and 9 for each MCN of Examples 2 to 4.

  According to the isotherm of FIG. 8, each has an H2 type hysteresis loop, is classified as type IV by IUPAC, and is characterized by capillary condensation in the mesopores. From this, it was found that all of the obtained MCNs are porous bodies in which well-oriented mesopores exist. Specifically, as the unit cell constant of MCN increases (that is, in order of MCN-1-100, MCN-1-130, MCN-1-150), the position of the capillary condensation step increases from the low pressure side of the relative pressure. Shifted to the high pressure side. In particular, the position of the capillary condensation step of MCN-1-150 is shifted to the highest pressure side, indicating an increase in the pore diameter. This coincides with the increase in the surface spacing d described with reference to FIG. 5 as the hole diameter increases.

  According to the pore size distribution of FIG. 9, with the increase in the pore size of the template (ie, in the order of SBA-15-100, SBA-15-130, SBA-15-150), the pore size of MCN also increased (ie, MCN-1-100, MCN-1-130, MCN-1-150 in this order).

  Specifically, the half width of the peak of the pore size distribution of MCN-1-150 was much larger than that of MCN-1-100 and MCN-1-130. MCN-1-150 had the largest pore diameter, and the pore diameter was about 6.4 nm. This is because although the template SBA-15-150 having a large pore diameter was used, the same weight ratio of EDA and CTC as 0.45 as in the case of the template SBA-15-100 having a small pore diameter was adopted. This is probably because EDA and CTC could not be filled sufficiently.

  Returning to FIG. 8 again, referring to the isotherm of MCN-1-130, the shape of the isotherm of MCN-1-130 is different from that of MCN-1-100 and MCN-1-150. A sharp rise in the isotherm in MCN-1-130 occurred on the higher temperature side relative to 0.8 relative pressure. This suggests the presence of tissue mesopores in MCN-1-130.

  FIG. 10 is a diagram showing an HRSEM image of MCN-1-100 of Example 2.

  FIG. 11 is a diagram showing an HRSEM image of MCN-1-130 of Example 3.

  FIG. 12 is a diagram showing an HRSEM image of MCN-1-150 of Example 4.

  10 to 12, many voids are seen in FIG. 11 (MCN-1-130), and in FIG. 10 (MCN-1-100) and FIG. 12 (MCN-1-150) There were few voids. According to FIG. 11, it turns out that the space | gap exists uniformly over the whole sample.

Further focusing on MCN-1-130, according to Table 3, the specific surface area and specific pore volume of MCN-1-130 are much larger than those of MCN-1-100 and MCN-1-150. I understood. Specifically, the specific surface area and specific pore capacity of MCN-1-130 were 830 m ² / g and 1.25 cm ³ / g, respectively. On the other hand, the specific surface area and specific pore capacity of MCN-1-100 and MCN-1-150 are 505 m ² / g and 0.55 cm ³ / g, and 650 m ² / g and 0.89 cm ³ / g, respectively. there were.

  FIG. 13 is a diagram showing an HRTEM image of MCN-1-130 of Example 3.

  FIG. 14 is a diagram showing an HRTEM image of MCN-1-150 of Example 4.

  13 and 14 show a plane (left figure) and a cross section (right figure) of the MCN. In the figure, the bright contrast strips represent the pore walls and the dark contrast core represents the empty channel. It should be noted that the contrast pattern changes as the lens blur is adjusted.

  According to the plan views of FIGS. 13 and 14, each MCN shows a linear arrangement of mesopores in which regular tubes having a length of 500 nm or more are arranged in a line. According to the cross-sectional views of FIGS. 13 and 14, each MCN shows a honeycomb structure in which hexagonal crystals are arranged together with a uniform porous body channel. From the cross-sectional views of FIGS. 13 and 14, the hole diameter of MCN-1-150 is larger than that of MCN-1-130, which matches the result of FIG. 9.

  FIG. 15 is a diagram showing an electron energy loss (EEL) spectrum of each MCN of Examples 2 to 4.

  Table 4 shows the results of elemental analysis of each MCN of Examples 2-4. The ratio of carbon atom to nitrogen atom calculated from the EEL spectrum and CHN analysis was calculated to be 4.3 ± 0.05. This value agrees well with the value of nonporous carbon nitride obtained by the chemical polymerization method.

  Table 4 also shows that H and other elements (Si, O or Cl) are present in the MCN even after removal of the template. The trace amount of H is due to moisture or ethanol adsorbed on the surface of MCN, or NH groups in the MCN matrix (described later).

As shown in FIG. 15, the shape of the EEL spectrum of any MCN was the same, indicating a CK edge and an NK edge. The CK and NK edges were located at 284 eV and 401 eV, respectively. The peak at 284 eV is attributed to the transition from 1 s to π ^* and is attributed to the trigonal sp ² hybrid carbon atom bonded to the nitrogen atom. On the other hand, a broad peak centered at 296 eV is also observed, but this peak is caused by a transition from the orbit 1s-σ ^* . The σ ^* characteristic of the CK edge indicates that the carbon atom is sp ² hybridized in any MCN. Moreover, since there was no sharp peak at 295 eV, it was found that no sp ³ CN bond was present in any MCN. The NK edge indicates that the nitrogen atom is hybridized with carbon and sp ² , and is consistent with the analysis result of the CK edge. In addition, none of the EEL spectra shows a peak of 500 eV or higher as seen in carbon nitride containing oxygen, indicating that the obtained MCN is mainly composed of C and N.

  FIG. 16 is a diagram showing C1s and N1s spectra of MCN-1-100 of Example 2.

  FIG. 17 is a diagram showing C1s and N1s spectra of MCN-1-130 of Example 3.

  FIG. 18 is a diagram showing C1s and N1s spectra of MCN-1-150 of Example 4.

  According to FIGS. 16-18, the shape of the C1s and N1s spectrum of any MCN and the peak position were the same. From this, it was found that the properties and coordination of the obtained MCN were not affected by the pore size of SBA-15 used for the template. 16 to 18, in order to examine the details of the chemical bond between the carbon atom and the nitrogen atom in the CN matrix of each MCN, the C1s peak and the N1s peak were reversely integrated into a Gaussian-Lorenzian form. The spectrum is shown.

  The C1s peak was deconvolved and integrated with peaks having three binding energies of 289.3 eV, 285.7 eV and 284.1 eV. On the other hand, the N1s peak was inversely integrated with two peaks having binding energies of 397.8 eV and 400.2 eV.

With reference to the C1s spectra in FIGS. 16 to 18, a peak centered at 284.1 eV is observed in any MCN. This peak is very sharp and has the highest intensity. This peak is attributed to pure graphite sites in the amorphous CN matrix. On the other hand, the peak centered at 285.7 eV is attributed to the sp ² carbon atom bonded to the carbon atom in the aromatic structure. The peak centered at 289.3 eV is due to the sp ² hybridized carbon atom in the aromatic ring attached to the NH ₂ group. These results were in good agreement with the values reported for nonporous carbon nitride.

Referring to the N1s spectra of FIGS. 16-18, peaks centered at 397.8 eV and 400.2 eV indicate that there are two types of carbon atoms in the MCN. Specifically, the peak centered at 397.8 eV is due to the nitrogen atom bonded to the graphite carbon atom, and the peak centered at 400.2 eV is to the carbon atom bonded to the sp ² carbon atom in a three-fold symmetry. Or due to a carbon atom bonded to an sp ² carbon atom and a hydrogen atom. Furthermore, since there is no peak on the higher bond energy side than 401 eV, it was found that MCN has no NN bond coordination formed from nitrogen molecules. These results are in good agreement with the results obtained for the C1s spectrum.

  From the intensity of the N1s spectrum, it can be seen that a considerable amount of nitrogen atoms in MCN are bonded to carbon atoms. Furthermore, it was confirmed that the amount of nitrogen atoms calculated from FIGS. 16 to 17 was consistent with the value obtained from CHN analysis. This also suggests that the nitrogen atoms are bonded to the carbon atoms and, in particular, are uniformly dispersed in the CN layer outside the MCN.

According to the XPS measurement of MCN after template removal, a remarkable peak was shown for O, but no peaks were shown for other elements except C, N and O (not shown). From this, it can be presumed that other elements detected in the obtained MCN are caused by oxygen atoms due to moisture, ethanol, air O ₂ or CO ₂ adsorbed on the surface of the MCN.

  FIG. 19 is a diagram showing an FT-IR spectrum of each MCN of Examples 2 to 4.

FIG. 19 shows three major broad bands centered around 1257 cm ⁻¹ , 1571 cm ⁻¹ and 3412 cm ⁻¹ . These bands are attributed to an aromatic CN stretch bond, an aromatic ring mode band, and an NH group stretch mode in the aromatic ring, respectively. These results were confirmed to be similar to those of non-porous carbon nitride.

  20 is a diagram showing a UV-vis absorption spectrum of MCN-1-100 of Example 2. FIG.

According to FIG. 20, two peaks with the maximum at 255 nm and 275 nm were shown. These peaks are all attributed to π → π ^* electron transition in a typical aromatic 1,3,5-triazine compound. Furthermore, the absorption properties of MCN-1-100 were found to be similar to that of nanoporous carbon nitride materials.

  FIG. 21 is a diagram showing a DD-MAS spectrum of each MCN of Examples 3 and 4.

The nature and environment of carbon atoms and nitrogen atoms in the wall structure of MCN obtained from FIG. 21 were examined. Each spectrum showed a sharp peak with a shoulder. This peak can be deconvolution integrated into two peaks with chemical shifts of 124 ppm and 141 ppm. Chemical shifts of 124ppm is due to the sp ² carbon atoms between the graphitic carbon layer, the chemical shifts of 141ppm is due to sp ² carbon atom attached to the nitrogen atom in the aromatic ring bonded to the terminal NH ₂ group. In addition, solid state ¹⁵ N spectroscopic analysis of MCN-1-130 and MCN-1-150 was also performed, but a ¹⁵ NDD-MAS spectrum was not obtained because the amount of nitrogen in each MCN was extremely low.

  As mentioned above, with reference to Examples 2-4, the example which manufactured MCN using SBA-15-T processed by various hydrothermal treatment temperature as SBA-15 which is a template has been demonstrated. It was found that when the hydrothermal treatment temperature of SBA-15 is in the range of 130 ° C. or higher and 150 ° C. or lower, MCN having a space group p6 mm can be obtained. In addition, if SBA-15 synthesized at a high hydrothermal treatment temperature is employed, MCN having a large pore diameter can be obtained, and if SBA-15 synthesized at a low hydrothermal treatment temperature is employed, MCN having a small pore diameter can be obtained. I found out that Furthermore, it has been found that when SBA-15 synthesized at a hydrothermal treatment temperature of 130 ° C. is employed, MCN having the largest specific surface area and specific pore volume can be obtained. From these, it was found that MCN having a desired pore diameter, specific surface area and specific pore volume can be obtained by appropriately adopting SBA-15 synthesized at various hydrothermal treatment temperatures as a template.

  Since it is the same as that of Example 3 except having set the weight ratio of EDA and CTC in a gel to 0.3, description is abbreviate | omitted. The MCN thus obtained is referred to as MCN-1-130-0.3.

  For MCN-1-130-0.3, XRD, specific surface area / pore distribution measurement, HRSEM and catalytic activity were measured in the same manner as in Example 3. The results are shown in FIGS. 22 to 26, FIG. 29, Table 6 and Table 7, and will be described later.

  Since it is the same as that of Example 3 except having set the weight ratio of EDA and CTC in a gel to 0.6, description is abbreviate | omitted. The MCN thus obtained is referred to as MCN-1-130-0.6.

  For MCN-1-130-0.6, XRD, specific surface area / pore distribution measurement, HRSEM and catalytic activity were measured in the same manner as in Example 3. The results are shown in FIGS. 22 to 25, FIG. 27, FIG. 29, Table 6 and Table 7, and will be described later.

  Since it is the same as that of Example 3 except having set the weight ratio of EDA and CTC in a gel to 0.9, explanation is omitted. The MCN thus obtained is referred to as MCN-1-130-0.9.

  For MCN-1-130-0.9, XRD, specific surface area / pore distribution measurement, HRSEM, EEL and catalytic activity were measured in the same manner as in Example 3. The results are shown in FIGS. 22 to 25, FIGS. 28 to 30, Tables 6 and 7, and will be described later.

  Table 5 summarizes the experimental conditions of Example 3 and Examples 5-7.

  FIG. 22 is a diagram illustrating XRD patterns on the low angle side of the MCNs of Examples 5 to 7.

  FIG. 22 also shows the XRD pattern of MCN-1-130-0.45 of Example 3. The XRD pattern of any MCN showed two higher order peaks indexed to the (100), (110) and (200) diffractions of the space group p6 mm of the two-dimensional hexagonal lattice. Therefore, any MCN has a uniform mesoporous structure oriented in a hexagonal lattice over a long period, and even if the weight ratio between EDA and CTC in the gel is changed, the structural orientation is not affected. I understood that.

  More specifically, as the weight ratio of EDA to CTC in the gel increases (ie, MCN-1-130-0.3, MCN-1-130-0.45, MCN-1-130-0. 6 in order of MCN-1-130-0.9), the peak shifted to the lower angle side. This indicates that the interplanar spacing d and unit cell constant of MCN can be controlled by changing the composition ratio (ie, EDA / CTC) in the gel.

  The unit cell constant increased from 9.7 nm to 11.3 nm as the weight ratio of EDA to CTC increased from 0.3 to 0.9. That is, if the amount of EDA in the gel is increased, the density of the reactant is reduced, and as a result, the diffusion of the reactive molecule into the porous matrix is promoted, and all the existing adsorption sites can be accessed. This promotes complete polymerization of EDA and CTC, and enables reliable filling of the CN polymer matrix in the voids and mesoporous spaces of the template SBA-15. Furthermore, high compression of the CN matrix within the mesopores results in an MCN having a larger unit cell constant. Due to the increase in unit cell constant and interplanar spacing d with increasing weight ratio of EDA to CTC, the pore structure of MCN also expands.

  FIG. 23 is a diagram showing nitrogen adsorption / desorption isotherms of MCNs of Examples 5 to 7.

  FIG. 23 also shows the nitrogen adsorption / desorption isotherm of MCN-1-130-0.45 of Example 3. According to the isotherm of FIG. 23, all have an H2 type hysteresis loop, are classified into type IV by IUPAC, and are characterized by capillary condensation in mesopores. Specifically, the capillary condensation step related to mesopore diameter shifted to higher relative pressure as the weight ratio of EDA to CTC increased. This suggests that the MCN pore size increases as the weight ratio of EDA to CTC increases.

  In FIG. 23, the shape of the isotherm of MCN-1-130-0.3 and MCN-1-130-0.45, and that of MCN-1-130-0.6 and MCN-1-130-0.9 The shape of the isotherm is completely different. In the isotherms of MCN-1-130-0.3 and MCN-1-130-0.45, a sharp increase was observed on the high relative pressure side. This means that there is a textured mesopore generated by the void space between the particles, which is caused by insufficient polymerization of EDA and CTC (ie, because the weight ratio of EDA and CTC is small). To suggest. As a result, MCN-1-130-0.3 and MCN-1-130-0.45 have a large mesopore and specific pore capacity.

  FIG. 24 is a diagram showing a BJH pore size distribution of each MCN of Examples 5 to 7.

  FIG. 24 also shows the BJH pore size distribution of MCN-1-130-0.45 of Example 3. According to the pore size distribution of FIG. 24, with the increase in the weight ratio of EDA and CTC (that is, the weight ratio is in the order of 0.3, 0.45, 0.6, 0.9), the pore size of MCN Increased (ie, MCN-1-130-0.3, MCN-1-130-0.45, MCN-1-130-0.6, MCN-1-130-0.9 in this order). This result agrees well with the change in the unit cell constant obtained from the XRD pattern of FIG.

  FIG. 25 is a diagram showing the weight ratio dependence of EDA and CTC of specific surface area, specific pore volume and pore size of MCN of Example 3 and Examples 5-7.

According to FIG. 25, the ratio pore volume of the MCN, as the weight ratio of EDA and CTC increases and decreases regularly from 1.5 cm ³ / g to 0.7 cm ³ / g. On the other hand, the specific surface area of the MCN, as the weight ratio of EDA and CTC increases from 0.3 to 0.45, up from 731cm ² / g to 818cm ² / g, the weight ratio of EDA and CTC 0 As increases from .45 to 0.9, was reduced from 818cm ² / g to 552cm ² / g. The MCN pore size increased from 3.2 nm to 5.7 nm as the weight ratio of EDA to CTC increased. Thus, according to the present invention, it was shown that MCN having a specific surface area, specific pore volume, and pore size according to the purpose can be obtained by controlling the weight ratio between EDA and CTC.

  FIG. 26 is a diagram showing an HRSEM image of MCN of Example 5.

  FIG. 27 is a diagram showing an HRSEM image of MCN in Example 6.

  FIG. 28 is a diagram showing an HRSEM image of MCN of Example 7.

  In addition to FIGS. 26 to 27, the HRSEM image of the MCN of Example 3 in FIG. 11 will be described in detail. All showed void space with a rod-like morphology similar to the template SBA-15. It was confirmed that the size of the void space increased as the weight ratio of EDA to CTC decreased (that is, in the order of FIG. 28, FIG. 27, FIG. 11 and FIG. 26). This is because when the weight ratio of EDA and CTC is small, the polymerization of the reaction mixture does not proceed completely. Insufficient polymerization promotes the decomposition of weakly bound organic species from the CN wall during carbonization, and a large number of void spaces, that is, textured mesopores are generated in the rod-like CN wall. As a result, MCN with a small weight ratio of EDA to CTC will have a large mesopore and a large specific pore volume. When the ratio of EDA to CTC exceeded 1.2, a thick gel-like material was obtained, an extremely low specific surface area and specific pore volume were exhibited, and the intended MCN was not obtained (not shown).

  FIG. 29 is a diagram showing the weight ratio dependency of the nitrogen content between EDA and CTC.

  According to FIG. 29, it can be seen that the nitrogen content in MCN can be easily controlled by adjusting the weight ratio of EDA and CTC. In detail, when obtaining MCN with high nitrogen content, it is preferable that the weight ratio of EDA and CTC is large, and when obtaining MCN with low nitrogen content, the weight ratio of EDA and CTC is small. It is preferable. Table 6 shows the results of CHN analysis of Example 3 and Examples 5-7.

  According to Table 6, as the weight ratio of EDA to CTC increased from 0.3 to 0.9, the ratio of carbon to nitrogen decreased from 4.5 to 3.3, ie, nitrogen The content increased.

  FIG. 30 is a diagram showing an EEL spectrum of MCN of Example 7.

FIG. 30 also shows the result of the EEL spectrum of the MCN of Example 3 shown in FIG. Both spectra showed peaks at 284 eV and 401 eV. These peaks suggest the presence of carbon atoms (CK edge: absorption by carbon k-shell electrons) and nitrogen atoms (NK edge: absorption by nitrogen k-shell electrons), respectively. The peak at 401 eV corresponds to a nitrogen atom hybridized with a carbon atom and sp ² . It should be noted that the MCN of Example 7 has a 401 eV peak intensity much higher than that of Example 3, and the ratio of carbon atom to nitrogen atom was determined from the peak area and the elastic scattering probability of each element. It was in good agreement with the results of CHN analysis.

  From FIG. 29, FIG. 30 and Table 6, the rapid increase in the nitrogen content in MCN accompanying the increase in the weight ratio between EDA and CTC indicates the polymerization of EDA and CTC when the weight ratio between EDA and CTC is large. This is thought to be due to the degree of conversion. This is because if the matrix is sufficiently polymerized, it is possible to suppress the escape of nitrogen atoms from the matrix during carbonization.

  Next, Table 7 shows the catalytic activity of MCN.

  According to Table 7, MCN-1-130-0.3 of Example 5 showed the highest conversion and 100% product selectivity for caprophenone. When the weight ratio between EDA and CTC is small, defects are generated in the CN wall of MCN due to insufficient polymerization of EDA and CTC as described above. This defect is composed of a large number of imine groups and amino groups, and as a result, the MCN of Example 5 has the highest catalytic activity.

  In the above, the example which manufactured MCN which changed the weight ratio of EDA and CTC was demonstrated with reference to Example 3 and Examples 5-7. It was found that the specific surface area, specific pore volume, pore size and nitrogen content of MCN can be adjusted by controlling the weight ratio between EDA and CTC.

As described above, according to the method of the present invention, since SBA-15 hydrothermally treated at a temperature of 100 ° C. or higher and 150 ° C. or lower is used, the unit cell constant is 9.5 nm to 10.5 nm, and the specific surface area is 500 m ^2. / g~830m ² / g, can be obtained Hiana capacity 0.55cm ³ /g~1.25cm ³ / g and controllable in a range of pore sizes 4.0nm~6.5nm a carbon nitride porous body. Furthermore, if the weight ratio of EDA and CTC is controlled, a carbon nitride porous body in which the nitrogen content is further controlled can be obtained. The carbon nitride porous body thus obtained can be applied to an adsorbent, a separating agent, a single catalyst, a battery electrode, a capacitor, and an energy storage body.

The flowchart which shows the manufacturing method of the carbon nitride porous body (MCN) by this invention Schematic diagram of porous carbon nitride (MCN) according to the present invention The figure which shows the XRD pattern of SBA-15-T (T = 100, 130, and 150) by Example 1. The figure which shows the procedure which manufactures the carbon nitride porous body The figure which shows the XRD pattern of the low angle side of each MCN of Examples 2-4 The figure which shows the XRD pattern of the high angle side of each MCN of Examples 2-4 Schematic diagram of wall structure of MCN according to the present invention The figure which shows the nitrogen adsorption-and-desorption isotherm of each MCN of Examples 2-4. The figure which shows BJH hole diameter distribution of each MCN of Examples 2-4 The figure which shows the HRSEM image of MCN-1-100 of Example 2. The figure which shows the HRSEM image of MCN-1-130 of Example 3. The figure which shows the HRSEM image of MCN-1-150 of Example 4. The figure which shows the HRTEM image of MCN-1-130 of Example 3. The figure which shows the HRTEM image of MCN-1-150 of Example 4. The figure which shows the electronic energy loss (EEL) spectrum of each MCN of Examples 2-4. The figure which shows the C1s and N1s spectrum of MCN-1-100 of Example 2. The figure which shows C1s and N1s spectrum of MCN-1-130 of Example 3 The figure which shows the C1s and N1s spectrum of MCN-1-150 of Example 4 The figure which shows the FT-IR spectrum of each MCN of Examples 2-4. The figure which shows the UV-vis absorption spectrum of MCN-1-100 of Example 2. The figure which shows DD-MAS spectrum of each MCN of Example 3 and 4 The figure which shows the XRD pattern of the low angle side of each MCN of Examples 5-7 The figure which shows the nitrogen adsorption-and-desorption isotherm of each MCN of Examples 5-7. The figure which shows BJH hole diameter distribution of each MCN of Examples 5-7 The figure which shows the weight ratio dependence of EDA and CTC of the specific surface area of MCN of Example 3 and Examples 5-7, a specific pore volume, and a pore diameter. The figure which shows the HRSEM image of MCN of Example 5. The figure which shows the HRSEM image of MCN of Example 6. The figure which shows the HRSEM image of MCN of Example 7. Figure showing the weight ratio dependence of nitrogen content between EDA and CTC The figure which shows the EEL spectrum of MCN of Example 7.

Explanation of symbols

  200 Carbon nitride porous material (MCN)

Claims (4)

A carbon nitride porous body (MCN) in which a porous polymer SBA-15 having a space group of p6 mm and a raw material containing nitrogen and carbon are mixed to carbonize a polymerized polymer, and then the silica porous body is removed. A manufacturing method comprising:
The porous silica SBA-15 has a space group p6 mm by hydrothermal treatment, and the hydrothermal treatment temperature is selected within the range having the space group p6 mm to adjust its pore diameter, specific surface area and specific pore volume. A method for producing a carbon nitride porous body (MCN), wherein 2. The method for producing a porous carbon nitride (MCN) according to claim 1, wherein the hydrothermal treatment temperature is selected in a range of 1 × 10 ² ° C to 1.5 × 10 ² ° C. Manufacturing method of body (MCN). The method for producing a porous carbon nitride (MCN) according to claim 1 or 2, wherein the raw materials are ethylenediamine and carbon tetrachloride.   The method according to claim 3, wherein a mass ratio of ethylenediamine and carbon tetrachloride in the raw material is 0.3 or more and 0.9 or less.