CN104874347B - A kind of TiO2Load the preparation method and applications of nitrogen-doped graphene sponge - Google Patents

Abstract

A kind of preparation method and applications of TiO2 loads nitrogen-doped graphene sponge, belong to technical field of function materials.Preparation method is to be added to contain titanium precursors in the alcohol dispersion liquid containing graphene oxide, deionized water is slowly added dropwise again, it stirs evenly to form mixed liquor, hydro-thermal reaction is carried out at 180~240 DEG C 12~48 hours, it takes out and is freeze-dried molding under the conditions of 80~75 DEG C, it is transferred to again in vacuum tube furnace and leads to high-purity nitrogenous gas, and be warming up in 400~800 DEG C and roast 3~12 hours, obtain the three-dimensional porous nitrogen-doped graphene sponge containing 5~10%TiO2.The material preparation method of the present invention is simple, its both adsorbable a large amount of formaldehyde or benzene-like compounds gas, and formaldehyde degradation by photocatalytic oxidation process or benzene-like compounds gas can be passed through under ultra violet lamp, avoid adsorption saturation phenomenon, absorption is carried out at the same time with degradation, it is complete to absorption, realize the purpose of efficient, rapid purification air.

Description

A kind of preparation method and application of TiO2 loaded nitrogen-doped graphene sponge

technical field

The invention belongs to the technical field of functional materials, and in particular relates to a preparation method and application of a TiO ₂ loaded nitrogen-doped graphene sponge with dual functions of adsorption and degradation.

Background technique

Due to the development of science and technology, urban residents spend most of their time indoors whether they are living or working, and the indoor air conditions will have a direct impact on the human body. At present, the coatings, paints, foam fillers and other materials used in home decoration and home furnishing contain organic pollutant gases such as formaldehyde, benzene, ammonia, etc. These gases gradually emit from the paint and home furnishing, causing great harm to the human body. . The common treatment method for indoor air pollutants is mainly through physical adsorption. Commonly used adsorbents include honeycomb and spherical activated carbon, activated carbon fiber, and molecular sieve. This method is simple and easy, but the adsorption selectivity is poor and regeneration is difficult. Another effective way to remove indoor air pollutants is to use semiconductor photocatalytic materials to decompose toxic and harmful substances into harmless and tasteless substances. The most promising photocatalytic catalyst for commercialization is nano-TiO ₂ , which has both adsorption and photocatalytic degradation. Functional materials with integrated functions are relatively rare. Graphene sponge is a new type of three-dimensional porous carbon material with a large specific surface area. At present, graphene sponge is mainly used for the adsorption of oil and organic solvents. There is no research report on the adsorption of gas pollutants in the air.

Contents of the invention

In view of the above problems existing in the prior art, the object of the present invention is to provide a TiO2 loaded nitrogen-doped graphene sponge with dual functions of adsorption and degradation, strong adsorption capacity and fast degradation rate and its application.

Described a kind of _TiO The preparation method of loaded nitrogen-doped graphene sponge is characterized in that the preparation method is as follows: add titanium-containing precursor in the ethanol dispersion liquid containing graphene oxide, then slowly add deionized water dropwise, stir evenly Form a mixed liquid, conduct a hydrothermal reaction at 180-240°C for 12-48 hours, take it out and freeze-dry it at -80-75°C, then transfer it to a vacuum tube furnace to pass high-purity nitrogen-containing gas, and raise the temperature to 400 Calcined at ~800°C for 3-12 hours to obtain a three-dimensional porous nitrogen-doped graphene sponge containing 5-10% TiO ₂ .

Described a kind of TiO ₂ The preparation method of nitrogen-doped graphene sponge is characterized in that the concentration of graphene oxide in the ethanol dispersion liquid containing graphene oxide is 1-2mg/ml.

The preparation method of a _TiO2- supported nitrogen-doped graphene sponge is characterized in that the time for adding deionized water is 30-60 minutes, and the hydrothermal reaction time is 20-24 hours.

The preparation method of a _TiO2 loaded nitrogen-doped graphene sponge is characterized in that the flow rate of the high-purity nitrogen-containing gas is 100ml/min, and the heating rate is 5°C/min.

The preparation method of a TiO _loaded nitrogen-doped graphene sponge is characterized in that the high-purity nitrogen-containing gas is passed for 3 to 12 hours at a temperature of 400 to 800° C., the firing temperature is 600 to 750° C., and the firing time is 600 to 750° C. 3 to 4 hours.

The preparation method of a _TiO2 loaded nitrogen-doped graphene sponge is characterized in that the titanium-containing precursor is tetrabutyl titanate or titanium tetrachloride.

Described a kind of _TiO The preparation method of loaded nitrogen-doped graphene sponge is characterized in that described preparation method is specifically as follows:

1) Measure the ethanol dispersion of graphene oxide containing 1-2 mg/ml, add the titanium-containing precursor, and then slowly add deionized water dropwise to form a mixed solution, stir evenly, and the ethanol dispersion of graphene oxide Liquid, tetrabutyl titanate and deionized water feed volume ratio is 45-55:5:2

2) Pour the mixed liquid obtained in step 1) into a hydrothermal reaction kettle, conduct a hydrothermal reaction at 180-240°C for 12-48 hours, and then cool naturally to obtain a graphene gel loaded with TiO ₂ ;

3) Freeze-dry the graphene gel obtained in step 2) at a low temperature of -80 to -75°C for 24 hours to obtain a three-dimensional porous TiO ₂ loaded graphene sponge;

4) Put the three-dimensional porous _TiO2 -loaded graphene sponge obtained in step 3) in a vacuum tube furnace, feed high-purity nitrogen-containing gas at a flow rate of 100ml/min, and heat up to 400-800°C at a rate of 5°C/min for roasting After 3-12 hours, a nitrogen-doped graphene sponge containing 4-5% TiO ₂ loaded is obtained.

The application of the _TiO2 loaded nitrogen-doped graphene sponge in the adsorption of formaldehyde or benzene compounds in the air.

The application of the TiO ₂ loaded nitrogen-doped graphene sponge is characterized in that after absorbing formaldehyde or benzene compounds, the formaldehyde or benzene compounds are degraded into carbon dioxide and water through photocatalysis.

The application of the TiO _loaded nitrogen-doped graphene sponge is characterized in that the benzene compounds include benzene, toluene and phenol.

By adopting above-mentioned technology, compared with prior art, the beneficial effect of the present invention is as follows:

1) The TiO ₂ loaded nitrogen-doped graphene sponge of the present invention is prepared by in-situ preparation to form a composite, which has simple operation and low equipment requirements, and can be widely used in industrial production;

2) The TiO2 _- loaded nitrogen-doped graphene sponge of the present invention has a dual-function effect, which can not only strongly adsorb formaldehyde or benzene compound gas, but also degrade it into non-toxic and harmless gases such as carbon dioxide through photocatalysis. To achieve the purpose of efficient and rapid air purification, it has unique advantages in performance;

3) After the TiO ₂ loaded nitrogen-doped graphene sponge of the present invention is used for a certain period of time, it can be activated and regenerated by simple methods such as washing and roasting, and then reused, thereby reducing the cost of use and improving economic benefits;

4) The preparation method of the TiO2 _- loaded nitrogen-doped graphene sponge of the present invention is simple, and it has dual functions, which can not only absorb a large amount of formaldehyde or benzene compounds, but also degrade formaldehyde or benzene compounds by photocatalysis under the irradiation of ultraviolet light Gas, to achieve the purpose of efficient and rapid air purification, suitable for popularization and application.

Detailed ways

The present invention will be further described below in conjunction with embodiment, but protection scope of the present invention is not limited thereto:

A kind of _TiO The preparation method of loading nitrogen-doped graphene sponge, specifically as follows: in the ethanol dispersion liquid containing 1-2mg/ml graphene oxide, add titanium-containing precursor, then slowly in 30-

Add deionized water dropwise within 60 minutes, stir evenly to form a mixed solution, carry out hydrothermal reaction at 180-240°C for 12-48 hours, the preferred reaction time is 20-24 hours, take it out at -80-75°C after the reaction Freeze-dried and formed, then transferred to a vacuum tube furnace to pass high-purity nitrogen-containing gas at a flow rate of 100ml/min, and heated to 400-800°C with a gradient of 5°C/min for 3-12 hours, preferably at 600°C ~750°C, with a preferred firing time of 3-4 hours, to obtain a three-dimensional porous nitrogen-doped graphene sponge containing 5-10% TiO ₂ .

In the present invention, the titanium-containing precursor is tetrabutyl titanate or titanium tetrachloride, the high-purity nitrogen-containing gas is nitrogen or ammonia, and its purity is more than 99.9%, and the ethanol dispersion of graphene oxide, titanium The volume ratio of tetrabutyl acid and deionized water is 45-55:5:2

The _TiO2 loaded nitrogen-doped graphene sponge obtained by the present invention has dual functions. It can not only absorb formaldehyde or benzene compounds such as benzene, toluene and phenol in the air, but also absorb formaldehyde or benzene by photocatalysis. The compound is degraded into carbon dioxide and water, and the TiO ₂ loaded nitrogen-doped graphene sponge can be continuously utilized through roasting and regeneration.

Embodiment 1: 5% _TiO The preparation method of loaded nitrogen-doped graphene sponge is as follows:

1) Measure 50 ml of ethanol dispersion of graphene oxide containing 2 mg/ml, add 5 ml of tetrabutyl titanate, then add 2 ml of deionized water dropwise within 30 minutes to form a mixed solution, and stir evenly;

2) Pour the mixed solution into a 100ml hydrothermal reaction kettle, react at a constant temperature of 180°C for 24 hours, then cool naturally, unscrew the hydrothermal reaction kettle to obtain TiO ₂ loaded graphene gel;

3) Freeze-dry the obtained graphene gel at -78°C for 24 hours to obtain a three-dimensional porous TiO ₂ loaded graphene sponge;

4) Put the obtained three-dimensional porous TiO ₂ loaded graphene sponge in a vacuum tube furnace, pass high-purity ammonia gas (99.999%) at a flow rate of 100ml/min, and heat up to 600°C at 5°C/min for 3 hours. A nitrogen-doped graphene sponge containing 5% TiO ₂ can be obtained.

Application: Put the nitrogen-doped graphene sponge loaded with 5% _TiO2 into a 100ml photocatalytic reactor, put in 0.3mg/ ^M3 formaldehyde, and take the gas in the reactor half an hour after sealing to analyze the formaldehyde content by GC. At this time, the formaldehyde content was obtained to be 0.2 mg/M ³ , indicating that the nitrogen-doped graphene sponge of the present invention has a certain adsorption effect on formaldehyde gas, and then a 30W ultraviolet lamp was used to carry out the light experiment, and within 2 hours, the Formaldehyde degrades completely.

In this embodiment, titanium tetrachloride is used to replace tetrabutyl titanate as the titanium-containing precursor, and nitrogen gas is used to replace ammonia gas as the high-purity nitrogen-containing gas, both of which can achieve the same technical effect.

Embodiment ₂ : 6%TiO The preparation method of loaded nitrogen-doped graphene sponge is as follows:

1) Measure 45ml of ethanol dispersion containing 1mg/ml graphene oxide, add 5ml of titanium tetrachloride, then add 2ml of deionized water dropwise within 60min to form a mixed solution, and stir evenly;

2) Pour the mixed solution into a 100ml hydrothermal reaction kettle, react at a constant temperature of 200°C for 24 hours, then cool naturally, unscrew the hydrothermal reaction kettle to obtain TiO ₂ loaded graphene gel;

3) Freeze-dry the obtained graphene gel at -80°C for 24 hours to obtain a three-dimensional porous TiO ₂ loaded graphene sponge;

4) Put the obtained three-dimensional porous TiO ₂ loaded graphene sponge in a vacuum tube furnace, pass high-purity nitrogen (99.999%) at a flow rate of 100 ml/min, and heat up to 400°C at 5°C/min for 12 hours. A nitrogen-doped graphene sponge _loaded with 6% TiO can be obtained;

5) Put the nitrogen-doped graphene sponge loaded with 4% TiO ₂ into a self-made photocatalytic reactor, put 0.5 mg/M ³ toluene into it, and take the gas in the reactor half an hour after sealing to analyze the toluene content by GC. At this time, the toluene content was found to be 0.35 mg/M ³ , which indicated that the nitrogen-doped graphene sponge had a certain adsorption effect on toluene gas. Then carry out the light experiment with a 50W ultraviolet lamp, and the toluene in the reactor will be degraded completely within 4 hours.

Embodiment 3: 7% _TiO The preparation method of loaded nitrogen-doped graphene sponge is as follows:

1) Measure 55 ml of ethanol dispersion containing 1.5 mg/ml graphene oxide, add 6 ml of titanium tetrachloride, then add 2.5 ml of deionized water dropwise within 45 minutes to form a mixed solution, and stir evenly;

2) Pour the mixed solution into a 100ml hydrothermal reaction kettle, react at a constant temperature of 180°C for 48 hours, then cool naturally, unscrew the hydrothermal reaction kettle to obtain TiO ₂ loaded graphene gel;

3) Freeze-dry the obtained graphene gel at -75°C for 48 hours to obtain a three-dimensional porous TiO ₂ loaded graphene sponge;

4) Put the obtained three-dimensional porous TiO ₂ loaded graphene sponge in a vacuum tube furnace, pass high-purity nitrogen (99.999%) at a flow rate of 100 ml/min, and heat up to 800°C at 5°C/min for 3 hours. A nitrogen-doped graphene sponge _loaded with 7% TiO can be obtained;

5) Put the nitrogen-doped graphene sponge loaded with 7% TiO ₂ into the photocatalytic reactor, put 0.2mg/M ³ phenol into it, and take the gas in the reactor half an hour after sealing to analyze the phenol content by GC. The phenol content was found to be 0.35 mg/M ³ , which indicated that the nitrogen-doped graphene sponge had a certain adsorption effect on phenol gas. Then use a 50W ultraviolet lamp to carry out the light experiment, and the phenol in the reactor will be completely degraded within 3 hours.

Embodiment four: 5% _TiO The preparation method of loaded nitrogen-doped graphene sponge is as follows:

1) Measure 50ml of ethanol dispersion of graphene oxide containing 2mg/ml, add 6ml of tetrabutyl titanate, then add 2.5 ml of deionized water dropwise within 50min to form a mixed solution, and stir evenly;

2) Pour the mixed solution into a 100ml hydrothermal reaction kettle, react at a constant temperature of 240°C for 12 hours, then cool naturally, unscrew the hydrothermal reaction kettle to obtain TiO ₂ loaded graphene gel;

3) Freeze-dry the obtained graphene gel at -78°C for 48 hours to obtain a three-dimensional porous TiO ₂ loaded graphene sponge;

4) Put the obtained three-dimensional porous TiO ₂ loaded graphene sponge in a vacuum tube furnace, pass high-purity ammonia gas (99.999%) at a flow rate of 100 ml/min, and heat up to 700°C at 5°C/min for 4 hours. , you can get 5% TiO ₂ loaded nitrogen-doped graphene sponge.

Put the obtained 5% _TiO loaded nitrogen-doped graphene sponge into the photocatalytic reactor, put in 0.3mg/ ^M3 formaldehyde and 0.3mg/ ^M3 toluene, and take the gas in the reactor half an hour after sealing. GC analyzes the content of formaldehyde and toluene. At this time, the content of formaldehyde is 0.25 mg/M ³ , and the content of toluene is 0.2 mg/M ³ . Then use a 50W ultraviolet lamp to conduct a light experiment, and the formaldehyde and toluene in the reactor will be completely degraded within 4 hours.

The preparation method of a TiO2-loaded nitrogen-doped graphene sponge of the present invention is simple, and the obtained material has dual functions, solves the problem of adsorption saturation in the current prior art, and can degrade while adsorbing until the toxic gas is adsorbed Completely, to achieve the purpose of rapidly purifying the air.

Claims (6)

1. a kind of TiO₂Load the preparation method of nitrogen-doped graphene sponge, it is characterised in that the preparation method is specific as follows：

1）The alcohol dispersion liquid of the graphene oxide of the mg/ml containing 1-2 is measured, is added and contains titanium precursors, then deionization is slowly added dropwise Water forms mixed liquor, stirs evenly, and described is titanium tetrachloride, the alcohol dispersion liquid of graphene oxide, tetrachloro containing titanium precursors It is 45 to change titanium and the deionized water volume ratio that feeds intake:5:2 or 55：6：2.5；

2）By step 1）Obtained mixed liquor pours into hydrothermal reaction kettle, and it is small that hydro-thermal reaction 12~48 is carried out at 180~240 DEG C When, then natural cooling, obtains TiO₂The Graphene gel of load；

3）By step 2）Obtained Graphene gel obtained three-dimensional porous in -80~-75 DEG C of frozen dryings 24 hours TiO₂Load graphene sponge；

4）By step 3）Obtain three-dimensional porous TiO₂Load graphene sponge is placed in vacuum tube furnace, by the stream of 100ml/min Amount is passed through high-purity nitrogenous gas, is warming up in 400~800 DEG C by 5 DEG C/min and roasts 3~12 hours to get to containing 4~5 % TiO₂The nitrogen-doped graphene sponge of load.

2. a kind of TiO according to claim 1₂Load nitrogen-doped graphene sponge preparation method, it is characterised in that go from The time for adding of sub- water is 30-60min, and the hydro-thermal reaction time is 20-24 hours.

3. a kind of TiO according to claim 1₂Load the preparation method of nitrogen-doped graphene sponge, it is characterised in that step 4）In, calcination temperature is 600~750 DEG C, and roasting time is 3~4 hours.

4. a kind of TiO that preparation method as described in claim 1 obtains₂Load nitrogen-doped graphene sponge first in adsorbing air Application in aldehyde or benzene-like compounds.

5. application as claimed in claim 4, it is characterised in that after formaldehyde adsorption or benzene-like compounds, then pass through photocatalysis Formaldehyde or benzene-like compounds are degraded to carbon dioxide, water.

6. application as claimed in claim 4, it is characterised in that the benzene-like compounds include benzene, toluene and phenol.