阅读说明：本技术 2D ZnO@3D CF纳米复合材料及其制备方法和应用 (2D ZnO @3D CF nano composite material and preparation method and application thereof ) 是由 别利剑 李明伟 张乐喜 邢月 于 2019-02-25 设计创作，主要内容包括：本发明公开了一种2D ZnO@3D CF纳米复合材料及其制备方法和应用,制备方法包括以下步骤：对三聚氰胺树脂泡沫进行清洗,干燥,升温至600～1000℃保温,冷却至室温,得到3D泡沫碳；将3D泡沫碳浸入溶液A中并保温,取出3D泡沫碳后进行清洗和干燥,得到3D CF,重复CF吸收锌方法6～12次,得到处理后CF,将处理后CF浸入溶液C中,再于80～100℃反应12～24h,降至室温,将该处理后CF浸入去离子水中1～5h,取出处理后CF清洗,干燥,再于200～350℃反应1～3h即可。该2D ZnO@3D CF纳米复合材料作为气敏材料时,在120℃较低的工作温度下能够表现出优异的气体敏感性能。(The invention discloses a 2D ZnO @3D CF nano composite material and a preparation method and application thereof, wherein the preparation method comprises the following steps: cleaning melamine resin foam, drying, heating to 600-1000 ℃, preserving heat, and cooling to room temperature to obtain 3D carbon foam; immersing 3D carbon foam into the solution A, preserving heat, taking out the 3D carbon foam, cleaning and drying to obtain 3D CF, repeating the method for absorbing zinc by CF for 6-12 times to obtain treated CF, immersing the treated CF into the solution C, reacting at 80-100 ℃ for 12-24 h, cooling to room temperature, immersing the treated CF into deionized water for 1-5 h, taking out the treated CF, cleaning, drying, and reacting at 200-350 ℃ for 1-3 h. When the 2D ZnO @3D CF nano composite material is used as a gas sensitive material, excellent gas sensitivity can be shown at a lower working temperature of 120 ℃.)

1. A preparation method of a 2D ZnO @3D CF nano composite material is characterized by comprising the following steps:

1) cleaning and drying the blocky melamine resin foam, heating to 600-1000 ℃ after drying, keeping the temperature for 1-3 h, and cooling to room temperature of 20-25 ℃ to obtain 3D carbon foam;

2) soaking the 3D carbon foam into a solution A at the temperature of 60-80 ℃, preserving heat for 6-12 hours, taking out the 3D carbon foam, cleaning and drying to obtain 3D CF, wherein the solution A is a mixture of mixed acid and deionized water, the volume fraction of the mixed acid in the solution A is 5-15%, and the mixed acid is a mixture of sulfuric acid and nitric acid;

3) repeating the CF zinc absorption method for 6-12 times to obtain the treated CF, wherein the CF zinc absorption method comprises the following steps: dropping the solution B on the 3D CF, drying after dropping, wherein the dropping amount of the solution B in each CF zinc absorption method is as follows: dropwise adding the solution B until 3DCF is saturated and does not absorb the solution B any more, wherein the dropwise adding speed is 1-2 mL/min, the solution B is a mixture of zinc chloride, glucose and deionized water, and the ratio of the mass parts of the zinc chloride to the mass parts of the glucose to the volume parts of the deionized water is 0.2: 0.27: 20;

4) immersing the treated CF obtained in the step 3) into a solution C, reacting at 80-100 ℃ for 12-24 h, cooling to room temperature of 20-25 ℃, immersing the treated CF into deionized water for 1-5 h, taking out the treated CF, cleaning, drying, and reacting at 200-350 ℃ for 1-3 h to obtain the 2D ZnO @3D CF nano composite material, wherein the solution C is a mixture of zinc chloride, urea, deionized water and dilute hydrochloric acid, and the ratio of the mass parts of the zinc chloride, the mass parts of the urea, the volume parts of the deionized water and the volume parts of the dilute hydrochloric acid is 0.002: 0.04: 40: 1, wherein the mass fraction of HCl in the dilute hydrochloric acid is 2-5 wt%.

2. The method according to claim 1, wherein when the unit of the mass part is g, the unit of the volume part is mL, and the amount part of the substance is mol.

3. The method for preparing the melamine resin foam according to claim 2, wherein in the step 1), the melamine resin foam is washed with deionized water: immersing melamine resin foam into deionized water, and then carrying out ultrasonic treatment for removing impurities, wherein the ultrasonic treatment time is more than or equal to 10 min;

in the step 1), the drying temperature is 50-80 ℃, and the drying time is 6-24 hours;

in the step 1), the melamine resin foam has the following dimensions: the length is 5-100 mm, the width is 5-100 mm, and the thickness is 2-20 mm;

in the step 1), the temperature rising speed is 4-10 ℃/min.

4. The production method according to claim 3, wherein, in the step 2),the sulfuric acid is sulfuric acid solution, and H in the sulfuric acid solution₂SO₄The mass fraction of (A) is 95-98%; the nitric acid is nitric acid solution, and HNO in the nitric acid solution₃The mass fraction of (A) is 60-65%;

in the step 2), before the 3D carbon foam is immersed into the solution A at the temperature of 60-80 ℃ and heat preservation is carried out for 6-12 hours, the 3D carbon foam is immersed into the solution A for 2-60 min by ultrasonic waves, and preferably 2-30 min;

in the step 2), the cleaning is to alternately clean the 3D carbon foam for more than 3 times by using deionized water and absolute ethyl alcohol;

in the step 2), the ratio of sulfuric acid to nitric acid in the mixed acid is 1: (3-6);

in the step 2), the drying temperature is 50-80 ℃, and the drying time is 6-24 hours;

in the step 3), the drying temperature is 50-80 ℃, and the drying time is 1-6 h.

5. The preparation method according to claim 4, wherein in the step 4), the drying temperature is 60-80 ℃, and the drying time is 12-24 h;

in the step 4), the treated CF cleaning is that the treated CF cleaning is alternately cleaned for more than 3 times by using deionized water and absolute ethyl alcohol;

in the step 4), the temperature rising speed of 200-350 ℃ is 5-10 ℃/min;

in the step 4), the reaction is carried out for 1 to 3 hours at 200 to 350 ℃, preferably for 1 to 3 hours at 200 to 250 ℃.

6. The production method according to claim 4, wherein in the step 4), the drying is freeze-drying;

in the step 4), the treated CF cleaning is that the treated CF cleaning is alternately cleaned for more than 3 times by using deionized water and absolute ethyl alcohol;

in the step 4), the temperature rising speed of 200-350 ℃ is 5-10 ℃/min;

in the step 4), the reaction is carried out for 1 to 3 hours at 200 to 350 ℃, preferably for 1 to 3 hours at 200 to 250 ℃.

7. The 2D ZnO @3D CF nanocomposite obtained by the preparation method according to any one of claims 1 to 6.

8. The use of the preparation method according to any one of claims 1 to 6 for reducing the working temperature of a gas-sensitive material.

9. Use according to claim 8, wherein the working temperature is 120 ℃.

10. The use of the 2D ZnO @3D CF nanocomposite of claim 7 in the detection of ethanol.

Technical Field

The invention belongs to the technical field of inorganic nano material preparation, and particularly relates to a 2D ZnO @3D CF nano composite material and a preparation method and application thereof.

Background

Ethanol is a flammable and explosive compound, has a low boiling point, and is very easy to volatilize or leak to cause safety accidents such as combustion or explosion, thereby causing great loss to the safety of human bodies and property. The ethanol gas in the air has serious stimulation to mouth, nose, skin, respiratory tract and the like, and can easily cause various diseases after long-term contact. The ethanol gas is widely applied to the fields of biochemistry, road safety, food and medicine safety and the like, and the detection of the ethanol gas is an important part in the modern detection technology. At present, common methods for detecting the ethanol gas comprise a gas chromatography method, an electrochemical sensor method, a Fourier transform infrared spectrum, a photoacoustic spectrum, a Raman spectrum and the like. However, these methods have some disadvantages: for example, the hysteresis of analysis and detection is not favorable for on-line detection, and the sample pretreatment and detection procedures are complicated.

The semiconductor gas metal oxide sensor is developed rapidly in recent years, and is widely applied to the fields of environmental gas monitoring, air quality control, chemical process control and the like, and the gas sensor detection method can just make up for the defects and shortcomings of the detection method. The core of the gas sensor is a gas sensitive material, so that the intensive research on the gas sensitive material is particularly important.

The semiconductor metal oxide gas sensor is prepared by utilizing the principle that when a gas sensitive material is exposed to a gas to be measured, the measured quantity (resistance, voltage and the like) changes along with the change of the type and the concentration of the gas to be measured, so that the gas sensitive material, the structure of a gas sensitive element and the gas sensitive performance are the key points of the research of the metal oxide gas sensor. A series of novel gas-sensitive materials are researched by optimally designing the composition and the microstructure of the gas-sensitive materials. The rise of nanotechnology has promoted the rapid development of material synthesis and preparation technologies, and gas sensors based on semiconductor metal oxides have made breakthrough progress in many aspects, such as sensitivity, operating temperature, stability, repeatability, selectivity, and the like. The performance enhancement method of the semiconductor metal oxide gas sensor is mainly reported to be the improvement of the specific surface area of the sensitive material (size reduction, control of synthesis porous structure, 3D hierarchical structure and the like) and the modification of the sensitive material (rare earth doping, noble metal loading, carbon doping, different semiconductor metal oxide compounding and the like). However, in the past scientific research work, the gas-sensitive property enhancement methods mainly pay attention to the improvement of the index of the sensitivity of the material, and when the working temperature is too high, the inside of the crystal grain of the semiconductor metal oxide can be aggregated, which has certain influence on the properties of the gas-sensitive material, such as reliability, stability and the like.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a preparation method of a 2D ZnO @3D CF nano composite material, which is green, simple, convenient and safe and can be used for producing the 2D ZnO @3D CF nano composite material in a large scale and batch manner.

The invention also aims to provide the 2D ZnO @3D CF nanocomposite material obtained by the preparation method, and the 2D ZnO @3D CF nanocomposite material can detect ethanol gas at a lower working temperature.

Another object of the present invention is the use of the above preparation method for reducing the working temperature of a gas-sensitive material.

The invention also aims to provide application of the 2D ZnO @3D CF nano composite material in detection of ethanol.

The purpose of the invention is realized by the following technical scheme.

A preparation method of a 2D ZnO @3D CF nano composite material comprises the following steps:

1) cleaning and drying the blocky melamine resin foam, heating to 600-1000 ℃ after drying, keeping the temperature for 1-3 h, and cooling to room temperature of 20-25 ℃ to obtain 3D carbon foam;

in the step 1), the melamine resin foam is washed by deionized water: and immersing the melamine resin foam into deionized water, and then carrying out ultrasonic treatment for removing impurities, wherein the ultrasonic treatment time is more than or equal to 10 min.

In the step 1), the drying temperature is 50-80 ℃, and the drying time is 6-24 h.

In the step 1), the melamine resin foam has the following dimensions: the length is 5-100 mm, the width is 5-100 mm, and the thickness is 2-20 mm.

In the step 1), the temperature rising speed is 4-10 ℃/min.

2) Soaking the 3D carbon foam into a solution A at the temperature of 60-80 ℃, preserving heat for 6-12 hours, taking out the 3D carbon foam, cleaning and drying to obtain 3D CF, wherein the solution A is a mixture of mixed acid and deionized water, the volume fraction of the mixed acid in the solution A is 5-15%, and the mixed acid is a mixture of sulfuric acid and nitric acid;

in the step 2), the sulfuric acid is a sulfuric acid solution (aqueous sulfuric acid solution) in which H is contained₂SO₄The mass fraction of (A) is 95-98%; the nitric acid is nitric acid solution (nitric acid aqueous solution), and HNO in the nitric acid solution₃The mass fraction of (A) is 60-65%.

In the step 2), before the 3D carbon foam is immersed in the solution A at the temperature of 60-80 ℃ and heat preservation is carried out for 6-12 hours, the 3D carbon foam is immersed in the solution A for 2-60 min through ultrasound, and preferably 2-30 min.

In the step 2), the cleaning is to alternately clean the 3D carbon foam for more than 3 times by using deionized water and absolute ethyl alcohol.

In the step 2), the ratio of sulfuric acid to nitric acid in the mixed acid is 1: (3-6).

In the step 2), the drying temperature is 50-80 ℃, and the drying time is 6-24 hours.

3) Repeating the CF zinc absorption method for 6-12 times to obtain the treated CF, wherein the CF zinc absorption method comprises the following steps: dropping the solution B on the 3D CF, drying after dropping, wherein the dropping amount of the solution B in each CF zinc absorption method is as follows: dropwise adding the solution B until the 3D CF is saturated and does not absorb the solution B any more, wherein the dropwise adding rate is 1-2 mL/min, the solution B is a mixture of zinc chloride, glucose and deionized water, and the ratio of the mass parts of the zinc chloride to the mass parts of the glucose to the volume parts of the deionized water is 0.2: 0.27: 20;

in the step 3), the drying temperature is 50-80 ℃, and the drying time is 1-6 h.

4) Immersing the treated CF obtained in the step 3) into a solution C, reacting at 80-100 ℃ for 12-24 h, cooling to room temperature of 20-25 ℃, immersing the treated CF into deionized water for 1-5 h, taking out the treated CF, cleaning, drying, and reacting at 200-350 ℃ for 1-3 h to obtain the 2D ZnO @3D CF nano composite material, wherein the solution C is a mixture of zinc chloride, urea, deionized water and dilute hydrochloric acid, and the ratio of the mass parts of the zinc chloride, the mass parts of the urea, the volume parts of the deionized water and the volume parts of the dilute hydrochloric acid is 0.002: 0.04: 40: 1, wherein the mass fraction of HCl in the dilute hydrochloric acid is 2-5 wt%.

In the step 4), the after-treatment CF cleaning is performed by alternately cleaning the after-treatment CF cleaning with deionized water and absolute ethyl alcohol for more than 3 times.

In the step 4), the drying temperature is 60-80 ℃, and the drying time is 12-24 hours.

In the step 4), the drying is freeze-drying.

In the step 4), the temperature rise speed of 200-350 ℃ is 5-10 ℃/min.

In the step 4), the reaction is carried out for 1 to 3 hours at 200 to 350 ℃, preferably for 1 to 3 hours at 200 to 250 ℃.

In the above technical solution, when the unit of the mass fraction is g, the unit of the volume fraction is mL, and the amount fraction of the substance is mol.

The 2D ZnO @3D CF nano composite material obtained by the preparation method.

The preparation method is applied to reducing the working temperature of the gas-sensitive material.

In the technical scheme, the working temperature is 120 ℃.

The 2D ZnO @3D CF nano composite material is applied to detection of ethanol.

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

the 2D ZnO @3D CF nanocomposite for detecting the ethanol gas, provided by the invention, has a proper porous structure and a higher specific surface area, and the preparation method is green, simple and safe, and has the advantages of simplicity and convenience in raw material acquisition and higher practicability. When the 2D ZnO @3D CF nano composite material is used as a gas sensitive material, the gas sensitive performance is excellent at a lower working temperature of 120 ℃, and compared with pure phase ZnO, the gas sensitive material has higher sensitivity, shorter response-recovery time, higher linearity, excellent selectivity and better repeatability on ethanol gas, and has great potential in the aspect of ethanol gas detection.

Drawings

FIG. 1 is a flow chart of a process for preparing a 2D ZnO @3D CF nanocomposite of the present invention;

FIG. 2 is an X-ray diffraction pattern of CF, ZnO and the 2D ZnO @3D CF nanocomposite prepared in examples 1-3, wherein FIG. 2(a) is CF, FIG. 2(b) is ZnO, FIG. 2(c) is 2D ZnO @3D CF-200, FIG. 2(D) is 2D ZnO @3D CF-250, and FIG. 2(e) is 2D ZnO @3D CF-350;

FIG. 3(a) is a scanning electron micrograph of CF;

FIG. 3(b) is a scanning electron micrograph of CF;

FIG. 3(c) is a scanning electron micrograph of the 2D ZnO @3D CF nanocomposite prepared in example 1;

FIG. 3(D) is a scanning electron micrograph of the 2D ZnO @3D CF nanocomposite prepared in example 1;

FIG. 3(e) is a scanning electron micrograph of the 2D ZnO @3D CF nanocomposite prepared in example 2;

FIG. 3(f) is a scanning electron micrograph of the 2D ZnO @3D CF nanocomposite prepared in example 2;

FIG. 3(g) is a scanning electron micrograph of the 2D ZnO @3D CF nanocomposite prepared in example 3;

FIG. 3(h) is a scanning electron micrograph of the 2D ZnO @3D CF nanocomposite prepared in example 3;

FIG. 4 is a Raman spectrum of the 2D ZnO @3D CF nanocomposite prepared in examples 1-3;

FIG. 5 shows the sensitivity of ZnO and the 2D ZnO @3D CF nanocomposite prepared in examples 1 to 3 to 200ppm of ethanol gas at different working temperatures;

FIG. 6 is a graph showing the dynamic response-recovery curves of a gas sensor made of the 2D ZnO @3D CF nanocomposite prepared in example 2 for ethanol gases with different concentrations;

FIG. 7(a) shows the selectivity of pure ZnO for different gases;

FIG. 7(b) is the selectivity of 2D ZnO @3D CF nanocomposites for different gases.

Detailed Description

In the following examples, the drugs and raw materials were all commercially available without any treatment before use, and were purchased from the following sources:

zinc chloride, analytical grade, kewei ltd, tianjin;

urea, analytically pure, kewei ltd, Tianjin;

absolute ethanol, analytically pure, kewei ltd, Tianjin;

glucose, analytical grade, kewei ltd, Tianjin;

the dilute hydrochloric acid in the following examples was prepared from 36-38% by mass (analytically pure) dilute hydrochloric acid purchased from Kewei GmbH of Tianjin;

concentrated sulfuric acid with mass fraction of 98% (analytical grade), Kewei Co of Tianjin;

concentrated nitric acid, 65% by mass (analytical grade), Kewei GmbH, Tianjin;

melamine resin foam, Shenzhen Germanchang sponge products GmbH;

benzene, analytically pure, kewei ltd, Tianjin;

toluene, analytically pure, Tianjin, Kewei, Inc.;

xylene, analytical grade, kewei ltd, tianjin;

acetone, analytical grade, kewei ltd, tianjin;

formaldehyde, analytical grade, kewei ltd, tianjin;

methanol, analytical grade, Kewei Co, Tianjin.

The following examples refer to the following instrument models and manufacturers:

x-ray diffractometer

The crystal phase structure of the experimental sample was characterized by an X-Ray diffractometer (XRD) of D/Max 2500pc type manufactured by Rigaku corporation of Japan, and Cu K_αThe radiation source was 0.15418nm wavelength, 40kV operating voltage. The scanning speed is 8 °/min, and the scanning range is 2 θ, which is 10 ° -80 °.

2. Field emission scanning electron microscope

The microscopic morphology of the sample was characterized by a Field Emission Scanning Electron Microscope (FE-SEM) model JSM-6700F produced by JEOL, a small amount of sample powder was uniformly stuck on a conductive adhesive, and the sample was observed after gold spraying treatment at an operating voltage of 10 kV.

3. High-resolution laser confocal micro-Raman spectrometer

Phase identification of the sample was performed by using HORIBA evolution type high-resolution laser confocal micro-Raman spectrometer (Raman) manufactured by HORIBA instrument ltd (HORIBA job Yvon), and a back scattering mode was used, and the excitation wavelength of argon ion laser was 535 nm. The samples were measured at room temperature.

The technical scheme of the invention is further explained by combining specific examples.

In the following examples, parts by mass are in g, parts by volume are in mL, and parts by mass are in mol.