CN101117222A

CN101117222A - A method for synthesizing high specific surface area mesoporous carbon molecular sieves using hard templates

Info

Publication number: CN101117222A
Application number: CNA2007101187551A
Authority: CN
Inventors: 戴洪兴; 张磊; 白燕楠; 何洪; 訾学红
Original assignee: Beijing University of Technology
Current assignee: Beijing University of Technology
Priority date: 2007-07-13
Filing date: 2007-07-13
Publication date: 2008-02-06
Anticipated expiration: 2027-07-13
Also published as: CN100564258C

Abstract

The invention discloses a method for synthesizing mesoporous carbon molecular sieves with high specific surface area by using a hard template, belonging to the field of preparation of solid mesoporous materials. It is difficult to synthesize mesoporous carbon molecular sieves with high specific surface area and well-developed pore structure by traditional methods. This method is divided into two steps: (1) Using tetra-block copolymer EO ₁₀₆ PO ₇₀ EO ₁₀₆ and cetyltrimethylammonium bromide are soft templates, by controlling the concentration and dosage of hydrochloric acid, EO ₁₀₆ PO ₇₀ EO ₁₀₆ and cetyltrimethylammonium bromide, the self-pressure After hydrothermal treatment at a certain temperature in the kettle, the polyhedral ordered mesoporous SBA-16 molecular sieve and the spherical worm-like mesoporous structure SBA-16 molecular sieve can be obtained. (2) Ordered mesoporous carbon molecular sieves and worm-like mesoporous carbon molecular sieves were synthesized by using SBA-16 with two morphologies as hard templates and sucrose as carbon source. The invention is suitable for use as adsorbent, catalyst carrier, electric double layer capacitor and hard template for synthesizing other mesoporous materials.

Description

A kind of method of utilizing the hard mould agent synthesizing high specific surface area meso-porous carbon molecular sieve

Technical field

The present invention relates to a kind of solid mesoporous material technology of preparing, be specifically related to a kind of method of utilizing mesoporous pure silicon molecular sieve (SBA-16) to come synthesizing high specific surface area meso-porous carbon molecular sieve as hard mould agent.

Background technology

In recent years, nanoparticle and ordered porous materials technology of preparing have obtained developing rapidly, make this type of material of controlledly synthesis become possibility.Because meso-porous carbon material not only has higher specific surface area and pore volume, but also have excellent in chemical inertia and mechanical stability, make its important research object that becomes aspects such as surface tissue and heterogeneous catalyst, be widely used in various fields such as atmosphere and water surrounding purification, gas delivery, heterogeneous catalyst, chromatogram, energy storage.Therefore, the preparation method of the meso-porous carbon molecular sieve of research and development high-specific surface area has great practical value.

The common preparation method of mesoporous carbon be via the raw material of natural or synthetic as presoma reactivate and getting after carbonization, these method major parts are hard template method.The main process of hard template method is to utilize preformed order mesoporous solid duct, desired inorganic salt precursor is impregnated in its duct, the mineralising precursor makes it be transformed into target components at a certain temperature, remove former solid template again, can obtain having the target product of meso-hole structure at last.For example, Ryoo etc. at first utilize Ia3d type MCM-48 molecular sieve to synthesize mesoporous CMK-1 (Ryoo R, et al., J.Phys.Chem.B as hard mould agent, 1999,103:7743) and CMK-4 (Kaneda M, et al., J.Phys.Chem.B, 2002,106:1256).Afterwards, this research group has synthesized CMK-2 (Ryoo R, the et al. of cube pm3n structure respectively with SBA-1 and SBA-15 again as template, Stud.Surf.Sci.Catal., 2001,135:150), CMK-3 (Jun S, et al., the J.Am.Chem.Soc. of two dimension six side p6mm structures, 2000,122:10712) and CMK-5 (Joo SH, et al., Nature, 2001,412:169).Recently, utilize macropore Ia3d type FDU-5 (YangH, et al., Chem.Commun., 2002,2842) and Fm3m type FDU-12 (Fan J, et al., Angew.Chem.Int.Ed., 2003,42:3146) also synthesized cubic-phase mesoporous carbon structure.Yet the space structure of above-mentioned mesoporous silicon material as the synthesising mesoporous carbon of hard template flourishing (for example SBA-15 only is two-dimentional hexagonal structure) and specific surface area inadequately is relatively low (generally at 1000m ²/ g is following), limited its application of synthesizing the highly developed meso-porous carbon molecular sieve of cell size as hard mould agent.The present invention utilizes the mesoporous SBA-16 molecular sieve of three-dimensional Im3m type bigger serface pure silicon (with the California, USA university Santa Barbara branch school name of synthetic SBA-16 first, be numbered 16, Zhao D, et al., J.Am.Soc.Chem., 1998,120:6024) be hard mould agent, opened up a kind of new way of synthetic bigger serface meso-porous carbon molecular sieve material.

Summary of the invention

The objective of the invention is to overcome other shortcoming that hard template method gained sample well compound with regular structure degree is relatively poor, specific surface area is lower in the past, the meso-porous carbon molecular sieve synthetic method of a kind of easy and simple to handle, target product specific surface area height and pore structure prosperity is provided.

The present invention is raw material with the tetraethoxy, with triblock copolymer EO ₁₀₆PO ₇₀EO ₁₀₆With cetyl trimethylammonium bromide be soft template, the mesoporous SBA-16 molecular sieve that synthesizes different-shape by hydro-thermal reaction, afterwards with it as hard mould agent, be carbon source with sucrose, obtain having the meso-porous carbon molecular sieve of highly developed pore structure and high-specific surface area.

A kind of method of utilizing the hard mould agent synthesizing high specific surface area meso-porous carbon molecular sieve is characterized in that, may further comprise the steps:

(1) at room temperature, in hydrochloric acid soln, add triblock copolymer EO ₁₀₆PO ₇₀EO ₁₀₆With the cetyl trimethylammonium bromide soft template, under violent stirring, add tetraethoxy and stirring;

When concentration of hydrochloric acid is 0.4mol/L and tetraethoxy: hydrochloric acid: EO ₁₀₆PO ₇₀EO ₁₀₆: the mol ratio of cetyl trimethylammonium bromide is 1: 3.5: 0.005: 0.02 o'clock, the surface topography of gained SBA-16 was a polyhedral;

When concentration of hydrochloric acid is 0.8mol/L and tetraethoxy: hydrochloric acid: EO ₁₀₆PO ₇₀EO ₁₀₆: the mol ratio of cetyl trimethylammonium bromide is 1: 6.9: 0.002: 0.02 o'clock, the surface topography of gained SBA-16 was spherical;

(2) the gained mixture is changed over to from pressing still 95 ℃ of thermostat(t)ed water thermal treatments 5 days, after filtration, behind the deionized water wash in 60 ℃ of dryings 12 hours;

(3) in retort furnace with the speed temperature programming to 550 of 1 ℃/min ℃ and 550 ℃ of following constant temperature calcinations 3 hours, obtain the SBA-16 white powder;

(4) SBA-16 is joined by sucrose: deionized water: massfraction is that 98% vitriol oil mol ratio is 1: 0.219: 20: in 0.0875 mixed solution of forming, magnetic agitation finishes the moisture evaporation in this mixed solution, and the baking oven of then it being put into 80 ℃ and 160 ℃ successively constant temperature was handled 6 hours;

(5) add in the gained powder by sucrose: deionized water: vitriol oil mol ratio is 0.132: 20: 0.05 mixed solution of forming, and magnetic agitation in the repeating step (4) and drying operation are once again;

(6) solid that obtains in nitrogen atmosphere with the speed temperature programming to 900 of 1 ℃/min ℃ and constant temperature calcination 2 hours under this temperature, with massfraction be 10%HF solution washing gained pressed powder to remove the silicon template, after seasoning, promptly obtain meso-porous carbon molecular sieve again.

With products therefrom X-ray diffractometer (XRD), N ₂Adsorption-desorption, scanning electronic microscope (SEM), transmission electron microscope technology such as (TEM) characterize.The result shows, the meso-porous carbon molecular sieve that adopting the obtained sample of present method is the pore structure prosperity, specific surface area is high, and specific surface area is 966～1600m ²/ g, mean pore size is 3.1～3.5nm.

The present invention has adopted a kind of simple hard template method to prepare the meso-porous carbon molecular sieve of multiple regular pattern.Present method preparation cost is low, operating process is easy, and the target product pore size distribution is narrow, and specific surface area is big, particle morphology is regular, and adjustable deliquescing template kind and consumption, hydro-thermal time and hydrothermal temperature etc. are realized the control to particle morphology, pore structure and specific surface area.

Description of drawings

For further understanding the present invention, elaborate with embodiment below, and provide accompanying drawing and describe the high specific surface area meso-porous carbon molecular sieve that the present invention obtains, wherein:

Figure 1A, 1B are respectively the mesoporous SBA-16 of institute's synthetic and as the Small angle XRD spectra of hard mould agent institute synthetic meso-porous carbon molecular sieve, wherein curve (a) is the Small angle XRD spectra of polyhedron SBA-16 among Figure 1A, and curve (b) is the Small angle XRD spectra of spherical SBA-16; Curve among Figure 1B (a) is the Small angle XRD spectra of embodiment 1 sample, and curve (b) is the Small angle XRD spectra of embodiment 2 samples.

Fig. 2 A, 2B are respectively the N of the mesoporous SBA-16 of institute's synthetic ₂Adsorption-desorption thermoisopleth and its pore size distribution curve, wherein curve (a) and (b) be respectively the N of polyhedron SBA-16 and spherical SBA-16 among Fig. 2 A ₂The adsorption-desorption thermoisopleth; Curve among Fig. 2 B (a) and (b) be respectively the pore size distribution curve of polyhedron SBA-16 and spherical SBA-16.

Fig. 3 A, 3B are respectively the N of embodiment 1～2 sample ₂Adsorption-desorption thermoisopleth and its pore size distribution curve, wherein curve (a) and (b) be respectively the N of embodiment 1 and embodiment 2 samples among Fig. 3 A ₂The adsorption-desorption thermoisopleth; Curve among Fig. 3 B (a) and (b) be respectively the pore size distribution curve of embodiment 1 and embodiment 2 samples.

Fig. 4 A, 4B are respectively the SEM photo of synthetic polyhedron SBA-16 of institute and spherical SBA-16.

Fig. 5 A, 5B are respectively the TEM photo of synthetic polyhedron SBA-16 of institute and spherical SBA-16.

Fig. 6 A, 6B are respectively the TEM photo of embodiment 1 and embodiment 2 samples.

Table 1 is for the synthetic SBA-16 of institute and as specific surface area, mean pore size and the pore volume of hard mould agent synthetic meso-porous carbon molecular sieve.

Embodiment

Embodiment 1: at room temperature, add EO in the 0.4mol/L hydrochloric acid soln ₁₀₆PO ₇₀EO ₁₀₆And cetyl trimethylammonium bromide, under violent stirring, add in the above-mentioned solution tetraethoxy and stirring, wherein tetraethoxy: hydrochloric acid: EO ₁₀₆PO ₇₀EO ₁₀₆: the mol ratio of cetyl trimethylammonium bromide is 1: 3.5: 0.005: 0.02, change over to from pressing still 95 ℃ of hydro-thermals 5 days, after filtration, following dry 12 hours behind the deionized water wash at 60 ℃, then in retort furnace with the speed temperature programming to 550 of 1 ℃/min ℃ and 550 ℃ of following calcinations 3 hours, obtain polyhedron SBA-16 white powder.It is in 98% the vitriol oil that sucrose is added to deionized water and massfraction, after polyhedron SBA-16 is added in the above-mentioned solution, SBA-16 wherein, sucrose, deionized water and massfraction are that 98% vitriol oil mole consisted of 1: 0.219: 20: 0.0875, mixture almost evaporates down to moisture in magnetic agitation, change in 80 ℃ of baking ovens and heated 6 hours, 160 ℃ were heated 6 hours, in the powder that obtains, add mol ratio again and be 0.132: 20: 0.05 sucrose, deionized water and massfraction are in the mixed solution of 98% the vitriol oil, and be transferred in 80 ℃ of baking ovens heating 6 hours, 160 ℃ were heated 6 hours, the solid that obtains is in 900 ℃ of calcinations 2 hours in the nitrogen atmosphere of 100ml/min with the speed temperature programming to 900 of 1 ℃/min ℃ and at flow velocity in nitrogen atmosphere, remove the silicon template with massfraction for the 10%HF solution washing at last, promptly get order mesoporous carbonaceous molecular sieve again after seasoning, its specific surface area is 1600m ²/ g, mean pore size is 3.1nm, pore volume is 1.42cm ³/ g.

Embodiment 2: at room temperature, add EO in the 0.8mol/L hydrochloric acid soln ₁₀₆PO ₇₀EO ₁₀₆And cetyl trimethylammonium bromide, under violent stirring, add in the above-mentioned solution tetraethoxy and stirring, tetraethoxy, hydrochloric acid, EO ₁₀₆PO ₇₀EO ₁₀₆With the mol ratio of cetyl trimethylammonium bromide be 1: 6.9: 0.002: 0.02, change over to from pressing still 95 ℃ of hydro-thermals 5 days, after filtration, dry down behind the deionized water wash at 60 ℃, then in retort furnace with the speed temperature programming to 550 of 1 ℃/min ℃ and 550 ℃ of following calcinations 3 hours, obtain spherical SBA-16 white powder.It is 98% the vitriol oil that sucrose is added to deionized water and massfraction, after spherical SBA-16 is added in the above-mentioned solution, SBA-16 wherein, sucrose, deionized water and massfraction are that 98% vitriol oil mole consisted of 1: 0.219: 20: 0.0875, mixture almost evaporates down to moisture in magnetic agitation, and placed 80 ℃ of baking oven constant temperature 6 hours, 160 ℃ were heated 6 hours, in the powder that obtains, add mol ratio again and be 0.132: 20: 0.05 sucrose, in deionized water and the vitriol oil mixed solution, and put into 80 ℃ of baking oven constant temperature and handled 6 hours, 160 ℃ were heated 6 hours, the solid that obtains is in 900 ℃ of calcinations 2 hours in the nitrogen atmosphere of 100ml/min with the speed temperature programming to 900 of 1 ℃/min ℃ and at flow velocity in nitrogen atmosphere, remove the silicon template with massfraction for the 10%HF solution washing at last, promptly get the carbonaceous molecular sieve of worm meso-porous structure again after seasoning, its specific surface area is 966m ²/ g, mean pore size is 3.5nm, pore volume is 0.91cm ³/ g.

Sample	Mean pore size (nm)	Specific surface area (m ²/g)	Pore volume 10 (cm ³/g)
Sample	Mean pore size (nm)	Specific surface area (m ²/g)	Pore volume 10 (cm ³/g)	The mesoporous SBA-16 of polyhedron	3.6	1011	1.00
Spherical mesoporous SBA-16	3.5	809	0.67	The mesoporous SBA-16 of polyhedron	3.6	1011	1.00
Spherical mesoporous SBA-16	3.5	809	0.67	By the order mesoporous carbonaceous molecular sieve of the mesoporous SBA-16 synthetic of polyhedron	3.1	1600	1.42
Carbonaceous molecular sieve by the worm meso-porous structure of spherical mesoporous SBA-16 synthetic	3.5	966	0.91		3.1	1600	1.42

Claims

1. a method utilizing hard template agent to synthesize high specific surface area mesoporous carbon molecular sieve, is characterized in that, comprises the following steps:

(1) At room temperature, add triblock copolymer EO ₁₀₆ PO ₇₀ EO ₁₀₆ and hexadecyltrimethylammonium bromide soft templating agent to the hydrochloric acid solution, under vigorous stirring, add ethyl orthosilicate and stir;

When the concentration of hydrochloric acid is 0.4mol/L and ethyl orthosilicate: hydrochloric acid: EO ₁₀₆ PO ₇₀ EO ₁₀₆ : The molar ratio of hexadecyltrimethylammonium bromide is 1: 3.5: 0.005: 0.02, the resulting SBA- The surface morphology of 16 is polyhedral;

When the concentration of hydrochloric acid is 0.8mol/L and ethyl orthosilicate: hydrochloric acid: EO ₁₀₆ PO ₇₀ EO ₁₀₆ : the molar ratio of hexadecyltrimethylammonium bromide is 1: 6.9: 0.002: 0.02, the resulting SBA- The surface morphology of 16 is spherical;

(2) Transfer the resulting mixture into an autoclave for hydrothermal treatment at a constant temperature of 95°C for 5 days, filter and wash with deionized water, and then dry at 60°C for 12 hours;

(3) In a muffle furnace, the temperature was programmed to rise to 550°C at a rate of 1°C/min and then burned at a constant temperature of 550°C for 3 hours to obtain a white powder of SBA-16;

(4) Add SBA-16 to the mixed solution composed of sucrose: deionized water: mass fraction of 98% concentrated sulfuric acid with a molar ratio of 1: 0.219: 20: 0.0875, and magnetically stir the water in the mixed solution to evaporate completely , and then put it into an oven at 80°C and 160°C for 6 hours successively at constant temperature;

(5) Add a mixed solution consisting of sucrose: deionized water: concentrated sulfuric acid molar ratio of 0.132: 20: 0.05 to the obtained powder, and repeat the magnetic stirring and drying operation in step (4) once;

(6) The obtained solid was heated up to 900° C. at a rate of 1° C./min in a nitrogen atmosphere and burned at a constant temperature at this temperature for 2 hours, and the obtained solid powder was washed with a mass fraction of 10% HF solution to remove the silicon template, After natural drying, the mesoporous carbon molecular sieve is obtained.