CN106564873B - A kind of big micro-diplopore film carbon material and preparation method thereof - Google Patents

Abstract

The invention discloses a kind of big micro-diplopore film carbon materials and preparation method thereof, it is template using hollow sphere calcium carbonate, load poly-dopamine film, intermediate product CaO@S-HFGB is obtained under high temperature cabonization, then CaO@S-HFGB is washed with water to neutrality and filters to obtain filter cake, by filtration cakes torrefaction, big micro-diplopore film carbon material is made.Hollow sphere calcium carbonate used in the present invention decomposes the CO of release during high temperature cabonization₂With efficient reaming effect, the problem of avoiding secondary carbonization and need to introduce expanding agent, one step carbonization can be obtained porous carbon materials S-HFGB；Preparation method of the invention is simple, process energy-saving and environment friendly, has great application potential in industrialization.

Description

A kind of large and micro double-hole carbon film material and preparation method thereof

technical field

The invention belongs to the technical field of material chemistry, and in particular relates to a large and micro double-hole film carbon material and a preparation method thereof.

Background technique

As an environmentally friendly material, porous carbon materials are extremely useful in gas adsorption, supercapacitors, and catalyst supports due to their low price, high specific surface area, modifiable pore structure, and excellent thermal stability. Great application potential. Porous carbon materials with special morphology and structure exhibit excellent performance in applications such as gas separation, drug sustained release, and catalysis, making their related preparation a research hotspot for scientists.

The hard template method is a common and effective method for synthesizing porous carbon materials. It generally consists of the following steps: (1) immersing the carbon precursor in the template agent; (2) allowing the precursor to polymerize on the template agent. Carbonization to obtain a carbon material with a specific shape; (3) remove the template agent in the carbon material; (4) add a pore-enlarging agent to the carbon material with a specific shape, and perform high-temperature carbonization to expand the pores to obtain a porous carbon material with a special shape . Common spherical templates include silica, ferric oxide, etc., but there are problems such as difficult removal of templates and easy collapse of carbon material morphology after removal. In addition, in the traditional hard template method, two carbonization steps and the addition of a pore-enlarging agent are required to achieve the effect of carbon material pore expansion, which seriously affects the product yield and energy consumption.

Calcium carbonate is a common inorganic material with many advantages such as low price, non-toxicity and good biocompatibility. Calcium carbonate products with different shapes can be prepared by using different processing methods and crystallization conditions, and can be used as templates in the preparation of porous carbon materials. Dopamine is a biological neurotransmitter. Under the condition of aqueous solution, it can undergo oxidation-crosslinking reaction under the action of dissolved oxygen to form a polydopamine composite thin layer (PDA) strongly attached to the surface of solid materials. It can be used as the precursor of carbon materials with special morphology.

The disclosure of the above background technical content is only used to assist in understanding the concept and technical solution of the present invention, and it does not necessarily belong to the prior art of this patent application. If there is no clear evidence that the above content has been disclosed on the filing date of this patent application In some cases, the above background technology should not be used to evaluate the novelty and inventiveness of this application.

Contents of the invention

The technical problem to be solved by the present invention is to provide a large and micro double-hole thin-film carbon material and its preparation method, so as to solve the problems that the traditional template agent is difficult to remove and the procedure of carbonization and pore expansion is cumbersome. In the high-temperature carbonization process of the present invention, the calcium carbonate in the composite material CaCO ₃ @PDA not only plays a role in supporting the morphology, but also the CO ₂ released by its high-temperature decomposition also has a high-efficiency pore-expanding effect; the method of the present invention solves the problem of traditional spherical templates It is difficult to remove and the shape is easy to collapse, and at the same time, it avoids the problem of secondary carbonization and the need to introduce a pore expander.

In order to solve the above technical problems, the present invention adopts the following technical solutions:

For this reason, the present invention proposes a carbon material with large and micro biporous films, which uses hollow spherical calcium carbonate as a template, loads polydopamine film, and obtains the intermediate product CaO@S-HFGB under high temperature carbonization, and then washes CaO@S-HFGB with water. HFGB is neutralized and filtered to obtain a filter cake, and the filter cake is dried to obtain a large and micro double-porous film carbon material.

The present invention also provides a method for preparing a large and micro double-porous film carbon material, comprising the following steps:

(1) Synthesis of hollow spherical calcium carbonate

Prepare 600mL polyvinylpyrrolidone aqueous solution, 800mL calcium chloride aqueous solution, 800mL sodium carbonate aqueous solution and 600mL sodium dodecylsulfonate aqueous solution respectively, and seal and stir the four different solutions respectively; take two volumes of 300mL prepared polyethylene The pyrrolidone solution was added to the prepared calcium chloride solution and sodium carbonate solution at the same time, and stirred vigorously for 0.5h under the condition of a water bath at 20°C; then the prepared sodium dodecylsulfonate solution was added to the above sodium carbonate solution solution, vigorously stirred for 0.5h; the above-mentioned calcium chloride solution was added to the mixed solution of sodium carbonate, and reacted for 2h under the conditions of a water bath temperature of 20°C and a stirring speed of 300r·min ^-1 ; after the reaction, the slurry was subjected to suction filtration, Wash with absolute ethanol and deionized water, repeat the above operation three times, and dry in vacuum at 80°C for 5 hours to obtain hollow spherical calcium carbonate;

(2) Preparation of CaCO ₃ @PDA composites

Prepare 100mL of dopamine saline solution, 50mL of hollow spherical calcium carbonate solution, and an alkaline solution prepared by 0.75mL of ammonia water, 40mL of ethanol, and 90mL of deionized water. The three different solutions are sealed and stirred evenly; the prepared calcium carbonate solution is added to In the dopamine salt solution, react for 0.5h under the conditions of water bath temperature 15-25°C and stirring speed 150-300r·min ^-1 ; add the prepared alkaline solution to the above-mentioned dopamine salt mixed solution, and the reaction temperature is the same as Keep the rotation speed constant, and react for 20 hours; filter the reacted slurry with suction, wash with deionized water, and vacuum dry at 80°C for 5 hours to prepare the CaCO ₃ @PDA composite material;

(3) Preparation of large and micro double-porous thin-film carbon materials

A certain mass of CaCO ₃ @PDA composite material sample was weighed and placed in a tube furnace. Under the protection of nitrogen, high-temperature carbonization was carried out to obtain the intermediate product CaO@S-HFGB, which was washed with deionized water until neutral, and finally The filter cake was dried in a vacuum oven at 80° C. for 5 hours to prepare a carbon material with large and micro double-porous films.

Further, the concentration of the polyvinylpyrrolidone aqueous solution in step (1) is 20 g·L ^-1 .

Further, the concentration of the calcium chloride aqueous solution in step (1) is 0.1 mol·L ^-1 .

Further, the concentration of the sodium carbonate aqueous solution in step (1) is 0.1 mol·L ^-1 .

Further, the concentration of the sodium dodecylsulfonate aqueous solution in step (1) is 0.05 mol·L ^-1 .

Further, the concentration of the dopamine saline solution in step (2) is 3-7 g·L ^-1 .

Further, the concentration of the hollow spherical calcium carbonate aqueous solution in step (2) is 8 g·L ^-1 .

Further, the following steps are used for washing the post-reaction slurry described in step (2), and the post-reaction slurry is suction-filtered with an organic filter membrane, and when the filtrate in the funnel is reduced to half, deionized water is added to fill the funnel, and the above operations are repeated Three times; dissolve the filter cake in deionized water, stir slowly for 4 hours, wash the membrane with water for suction filtration, repeat the first suction filtration process twice, and finally put the filter cake in a vacuum drying oven at 80°C for 5 hours to dry.

Further, the high-temperature carbonization procedure described in step (3) includes the following steps:

(a) Heating process: the CaCO ₃ @PDA composite sample was raised from room temperature to 700-900 °C at a rate of 2-10 °C min ^-1 ;

(b) Constant temperature process: keep the CaCO ₃ @PDA composite sample at 700-900°C for 1-3 hours;

(c) Cooling process: naturally cool the precursor from 700 to 900°C to room temperature.

Compared with the prior art, the present invention has the following beneficial effects:

(1) The present invention uses hollow spherical calcium carbonate as a template, which is decomposed into calcium oxide and carbon dioxide after high-temperature carbonization, and the calcium oxide can be removed with water, which solves the problem that the template is difficult to remove in the later stage;

(2) The hollow spherical calcium carbonate used in the present invention, in the high-temperature carbonization process, the _CO released by its decomposition has efficient pore-expanding effect, avoids secondary carbonization and needs to introduce the problem of pore-enlarging agent, and one-step carbonization method can obtain Porous carbon material S-HFGB;

(3) One-step carbonization method of the present invention, compared with traditional two-step carbonization method, product yield is higher;

(4) The product prepared by the present invention has a novel structure with a large and micro double-pore structure, and the specific surface area is higher;

(5) The preparation method of the present invention is simple, the process is green, energy-saving and environment-friendly, and has great application potential in industrialization.

Description of drawings

Fig. 1 is the SEM and TEM figure of the embodiment of the present invention one hollow spherical calcium carbonate and S-HFGB;

Fig. 2 is an analysis diagram of the element content of composite material CaO@S-HFGB and S-HFGB after washing according to Example 1 of the present invention;

Fig. 3 is the XRD pattern of hollow spherical calcium carbonate, CaO@S-HFGB and S-HFGB of the embodiment of the present invention;

Fig. 4 is the TG figure of the embodiment of the present invention one hollow spherical calcium carbonate, CaCO ₃ @PDA;

Fig. 5 is the N ₂ adsorption-desorption diagram of S-HFGB in Example 1 of the present invention.

Detailed ways

The present invention will be further described in detail below in combination with specific embodiments and with reference to the accompanying drawings. It should be emphasized that the following description is only exemplary and not intended to limit the scope of the invention and its application.

Example 1

A method for preparing a large and micro double-hole thin film carbon material, comprising the following steps:

(1) Synthesis of hollow spherical calcium carbonate

Prepare 600 mL of polyvinylpyrrolidone (PVP) aqueous solution with a concentration of 20 g·L ^-1 , 800 mL of an aqueous solution of calcium chloride (CaCl ₂ ^{) with a concentration of 0.1 mol·L -1 ,} and sodium carbonate (Na ₂ CO ₃ ) 800mL of aqueous solution and 600mL of sodium dodecylsulfonate (SDS) aqueous solution with a concentration of 0.05mol L ^-1 , four different solutions were sealed and stirred evenly; two parts (300mL each) of the prepared PVP solution were taken, respectively Add it to the prepared CaCl ₂ solution and Na ₂ CO ₃ solution, and stir vigorously for 0.5 h under the condition of a water bath at 20°C; then add the prepared SDS solution to the above Na ₂ CO ₃ solution, and stir vigorously for 0.5 h; Add the above-mentioned CaCl ₂ solution into the mixed solution of Na ₂ CO ₃ , and react for 2 hours at a water bath temperature of 20°C and a stirring speed of 300r·min ^-1 ; Washing with water, repeating the above operation three times, drying in vacuum at 80°C for 5 hours, to obtain a hollow spherical calcium carbonate product;

(2) Preparation of CaCO ₃ @PDA composites

The preparation concentration is 5g L ^-1 dopamine salt (DA) aqueous solution 100mL, concentration 8g L ^-1 hollow spherical calcium carbonate aqueous solution 50mL, namely weight ratio is 1.25DA/ _1.0CaCO Dopamine salt and hollow spherical calcium carbonate, and by Weak alkaline solution prepared by 0.75mL ammonia water, 40mL ethanol, and 90mL deionized water. The three different solutions were sealed and stirred evenly; the prepared calcium carbonate aqueous solution was added to the dopamine saline solution, and the temperature of the water bath was 20°C, and the stirring speed was 200r Under the condition of min ^-1 , react for 0.5h; add the prepared weak alkaline solution into the above dopamine salt mixed solution, keep the reaction temperature and rotation speed unchanged, and react for 20h; Washing with ion water and drying in vacuum at 80°C for 5 hours to prepare the CaCO ₃ @PDA composite material;

(3) Preparation of large and micro double-porous thin-film carbon materials

A certain mass of CaCO ₃ @PDA sample was weighed and placed in a tube furnace. Under the protection of nitrogen, high-temperature carbonization was carried out. The carbonization conditions were as follows: the CaCO ₃ ^@PDA sample was raised from room temperature to To 700 ℃, keep the temperature for 1 hour, and then naturally cool to room temperature; the intermediate product CaO@S-HFGB was obtained, which was washed to neutral with deionized water, and finally the carbon material S-HFGB-1 was obtained.

Example 2

Except following change, all the other are the same as embodiment 1.

Preparation concentration is 3g L ^-1 dopamine salt (DA) aqueous solution 100mL, concentration 8g L ^-1 hollow spherical calcium carbonate aqueous solution 50mL, namely weight ratio is 0.75DA/ _1.0CaCO Dopamine salt and hollow spherical calcium carbonate, and by Weak alkaline solution prepared by 0.75mL ammonia water, 40mL ethanol, and 90mL deionized water. The three different solutions were sealed and stirred evenly; the prepared calcium carbonate aqueous solution was added to the dopamine saline solution, and the temperature of the water bath was 15°C, and the stirring speed was 150r Under the condition of min ^-1 , react for 0.5h; add the prepared weak alkaline solution to the above dopamine salt mixed solution, keep the reaction temperature and rotation speed constant, and react for 20h to obtain the intermediate product CaCO ₃ @PDA;

A certain mass of CaCO ₃ @PDA sample was weighed and placed in a tube furnace. Under the protection of nitrogen, high-temperature carbonization was carried out. The carbonization conditions were as follows: the CaCO ₃ ^@PDA sample was raised from room temperature to To 800 ℃, keep the temperature for 2 hours, and then naturally cool to room temperature; the intermediate product CaO@S-HFGB was obtained, which was washed to neutral with deionized water, and finally the carbon material S-HFGB-2 was obtained.

Example 3

Except following change, all the other are the same as embodiment 1.

Prepare 100 mL of dopamine salt (DA) aqueous solution with a concentration of 6 g L ^-1 , and 50 mL of hollow spherical calcium carbonate aqueous solution with a concentration of 8 g L ^-1 , that is, the dopamine salt and hollow spherical calcium carbonate with a weight ratio of 1.5DA/ _1.0CaCO3 , and Weakly alkaline solution prepared by 0.75mL ammonia water, 40mL ethanol, and 90mL deionized water. The three different solutions were sealed and stirred evenly; the prepared calcium carbonate aqueous solution was added to the dopamine saline solution, and the temperature of the water bath was 25°C, and the stirring speed was 300r Under the condition of min ^-1 , react for 0.5h; add the prepared weak alkaline solution to the above dopamine salt mixed solution, keep the reaction temperature and rotation speed constant, and react for 20h to obtain the intermediate product CaCO ₃ @PDA;

A certain mass of CaCO ₃ @PDA sample was weighed and placed in a tube furnace. Under the protection of nitrogen, high-temperature carbonization was carried out. The carbonization conditions were as follows: the CaCO ₃ ^@PDA sample was raised from room temperature to To 900 ℃, keep the temperature for 3 hours, and then naturally cool to room temperature; the intermediate product CaO@S-HFGB was obtained, which was washed to neutral with deionized water, and finally the carbon material S-HFGB-3 was obtained.

Case Analysis

As shown in Figure 1, the S-HFGB porous carbon material prepared by the present invention has a hollow spherical morphology, indicating that the template calcium carbonate has been completely decomposed into calcium oxide and removed by water washing, and the morphology has not collapsed after washing. Among them, the SEM image shows that the hollow spherical calcium carbonate with a particle size of about 5 μm is composed of many flake particles with uniform particle size and orderly arrangement.

As shown in Figure 2, the carbon content of the S-HFGB prepared by the present invention is as high as 84.5%; the calcium content of CaO@S-HFGB and S-HFGB after washing are 15.3% and 0.26%, respectively, indicating that calcium oxide Has been completely removed by washing.

As shown in Figure 3, the hollow spherical calcium carbonate prepared by the present invention is calcite type, and the XRD pattern of the intermediate product CaO@S-HFGB has no characteristic peaks of calcium carbonate calcite type, indicating that the calcium carbonate in CaCO ₃ @PDA has been completely decomposed into calcium oxide. Among them, the XRD pattern of S-HFGB has graphitization characteristic peaks at 26° and 44°, (002) and (100) crystal planes, indicating that S-HFGB has a partially graphitized structure.

As shown in Figure 4, the decomposition temperatures of the hollow spherical calcium carbonate and CaCO ₃ @PDA prepared by the present invention are 605°C and 675°C respectively, and the weight loss rate of CaCO ₃ @PDA is about 55% when the temperature rises to 900°C in the greenhouse .

As shown in Figure 5, the _N2 adsorption and desorption of S-HFGB prepared by the present invention, and the pore structure of the resulting material are shown in Table 1. It can be seen that S-HFGB has a high specific surface area and macro-micro-double pore structure. The BET and Langmuir specific surface areas are 719.9m ² ·g ^-1 and 955.6m ² ·g ^-1 respectively, and the proportion of micropores is 26.08%.

Table 1 Pore structure parameters of S-HFGB

Those skilled in the art will recognize that many variations on the above description are possible, so the examples and figures are merely illustrative of one or more particular implementations.

Although there have been described and described what are considered to be exemplary embodiments of the present invention, it will be apparent to those skilled in the art that various changes and substitutions may be made therein without departing from the spirit of the invention. In addition, many modifications may be made to adapt a particular situation to the teachings of the invention without departing from the inventive central concept described herein. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but the present invention may also include all embodiments and their equivalents falling within the scope of the present invention.

Claims (9)

1. A preparation method for a large and micro double-hole film carbon material, characterized in that: the described large and micro double-hole film carbon material utilizes hollow spherical calcium carbonate as a template agent, loads a polydopamine film, and obtains intermediate carbonization under high-temperature carbonization. The product CaO@S-HFGB, followed by washing CaO@S-HFGB with water to neutrality and filtering to obtain a filter cake, was obtained by drying the filter cake; The preparation method of the described large and micro double-porous thin-film carbon material comprises the following steps: (1) Synthesis of hollow spherical calcium carbonate Prepare 600mL polyvinylpyrrolidone aqueous solution, 800mL calcium chloride aqueous solution, 800mL sodium carbonate aqueous solution and 600mL sodium dodecylsulfonate aqueous solution respectively, and seal and stir the four different solutions respectively; take two volumes of 300mL prepared polyethylene The pyrrolidone solution was added to the prepared calcium chloride solution and sodium carbonate solution at the same time, and stirred vigorously for 0.5h under the condition of a water bath at 20°C; then the prepared sodium dodecylsulfonate solution was added to the above sodium carbonate solution solution, vigorously stirred for 0.5h; the above-mentioned calcium chloride solution was added to the mixed solution of sodium carbonate, and reacted for 2h under the conditions of a water bath temperature of 20°C and a stirring speed of 300r·min ^-1 ; after the reaction, the slurry was subjected to suction filtration, Wash with absolute ethanol and deionized water, repeat the above operation three times, and dry in vacuum at 80°C for 5 hours to obtain hollow spherical calcium carbonate; (2) Preparation of CaCO ₃ @PDA composites Prepare 100mL of dopamine saline solution, 50mL of hollow spherical calcium carbonate solution, and an alkaline solution prepared by 0.75mL of ammonia water, 40mL of ethanol, and 90mL of deionized water. The three different solutions are sealed and stirred evenly; the prepared calcium carbonate solution is added to In the dopamine salt solution, react for 0.5h under the conditions of water bath temperature 15-25°C and stirring speed 150-300r·min ^-1 ; add the prepared alkaline solution to the above-mentioned dopamine salt mixed solution, and the reaction temperature is the same as Keep the rotation speed constant, and react for 20 hours; filter the reacted slurry with suction, wash with deionized water, and vacuum dry at 80°C for 5 hours to prepare the CaCO ₃ @PDA composite material; (3) Preparation of large and micro double-porous thin-film carbon materials A certain mass of CaCO ₃ @PDA composite material sample was weighed and placed in a tube furnace. Under the protection of nitrogen, high-temperature carbonization was carried out to obtain the intermediate product CaO@S-HFGB, which was washed with deionized water until neutral, and finally The filter cake was dried in a vacuum oven at 80° C. for 5 hours to prepare a carbon material with large and micro double-porous films. 2 . The method for preparing a large-micro-biporous film carbon material according to claim 1 , wherein the concentration of the polyvinylpyrrolidone aqueous solution in step (1) is 20 g·L ⁻¹ . 3 . The method for preparing a large-micro-double-porous thin-film carbon material according to claim 1 , wherein the concentration of the calcium chloride aqueous solution in step (1) is 0.1 mol·L ⁻¹ . 4 . The preparation method of large and micro double-porous film carbon material according to claim 1 , characterized in that the concentration of the sodium carbonate aqueous solution in step (1) is 0.1 mol·L ⁻¹ . 5 . The method for preparing a large and micro double-porous film carbon material according to claim 1 , characterized in that the concentration of the sodium dodecylsulfonate aqueous solution in step (1) is 0.05 mol·L ⁻¹ . 6 . The method for preparing a carbon material with large and micro biporous films according to claim 1 , wherein the concentration of the dopamine saline solution in step (2) is 3-7 g·L ⁻¹ . 7 . The preparation method of large and micro double-porous thin film carbon material according to claim 1 , characterized in that the concentration of the hollow spherical calcium carbonate aqueous solution in step (2) is 8 g·L ⁻¹ . 8. the preparation method of large and micro double-porous film carbon material according to claim 1 is characterized in that: the slurry washing after the reaction described in the step (2) takes the following steps to process, and the slurry after the reaction is pumped with an organic filter membrane When the filtrate in the funnel drops to half, add deionized water to the full funnel, repeat the above operation three times; dissolve the filter cake in deionized water, stir slowly for 4h, wash the membrane with water and carry out suction filtration, according to the first suction filtration process Repeat twice, and finally put the filter cake into a vacuum oven at 80° C. for 5 hours to dry. 9. the preparation method of large and micro double-porous film carbon material according to claim 1, is characterized in that: the high-temperature carbonization program described in step (3) comprises the following steps: (a) Heating process: the CaCO ₃ @PDA composite sample was raised from room temperature to 700-900 °C at a rate of 2-10 °C min ^-1 ; (b) Constant temperature process: keep the CaCO ₃ @PDA composite sample at 700-900°C for 1-3 hours; (c) Cooling process: the CaCO ₃ @PDA composite sample was naturally cooled from 700 to 900 °C to room temperature.