CN102877151A - Preparation method of CdS/carbon nano tube/polyacrylonitrile hybrid nano-fiber - Google Patents

Abstract

The invention relates to a preparation method of CdS-OH/carbon nanotube/polyacrylonitrile hybrid nanofiber. The technical solution is to synthesize CdS-OH/DMF suspension with CdCl ₂ , Na ₂ S and 2-mercaptoethanol as raw materials and N,N-dimethylformamide (DMF) and water as solvents; (CNT) is uniformly dispersed in the CdS-OH/DMF suspension, and then the CNT/CdS-OH/DMF suspension is slowly added to the prepared polyacrylonitrile/DMF solution, stirred, and ultrasonically obtained to obtain a mixed spinning solution; Electrospinning technology to obtain hybrid nanofibers. The invention adopts the combination of the solution growth method and the electrospinning method, the process is simple, and the prepared hybrid nanofiber has the characteristics of large specific surface area and good mechanical properties. At the same time, it also has high-efficiency photocatalytic degradation of organic dyes, and the hybrid nanofiber is easier to recycle than powdery photocatalytic materials.

Description

Preparation method of CdS/carbon nanotube/polyacrylonitrile hybrid nanofiber

technical field

The invention relates to the field of nanometer materials, in particular to a preparation method of CdS-OH/carbon nanotube/polyacrylonitrile hybrid nanofiber. The hybrid nanofiber material can be used for photocatalytic materials.

Background technique

Cadmium sulfide (CdS) nanoparticles are a very important II-VI semiconductor material with a band gap energy of 2.42eV at room temperature. CdS has nonlinear optical properties, fluorescence properties and quantum size effect, so it has been widely studied by researchers. CdS nanoparticles have a large specific surface area and are prone to agglomeration. In order to avoid the occurrence of agglomeration, how to use stabilizers to control the morphology of nanoparticles has become an important research topic and a realistic problem that needs to be solved urgently in practical applications. One of the very simple and mild synthetic methods is to use 2-mercaptoethanol (ME) as an organic ligand at room temperature to obtain monodisperse CdS nanoparticles (CdS-OH) modified by hydroxyl groups (Feng et al., CdS nanoparticles chemically modified PAN functional materials: preparation and nonlinear optical properties, Eur. Polym. J., 2009, 45, 1058-1064).

In order to maintain or even further improve the excellent properties of CdS nanoparticles, an effective technology is to combine CdS nanoparticles and polymers to make organic-inorganic hybrid materials. The polymer not only serves as a carrier, but also prevents the aggregation of CdS nanoparticles, controls the size and distribution of nanoparticles, and improves their photostability. Electrospinning can easily prepare polymer nanofibers with a diameter of tens to hundreds of nanometers, and its yield is high, which can meet the applications in filtration, catalysis, composite and scaffold materials. The most important feature of nanofibers is their high surface area and large aspect ratio. In order to make full use of these characteristics, CdS/polyacrylonitrile (PAN) hybrid nanofibers have been prepared by combining electrospinning and solution immersion. However, since CdS is introduced into the surface of nanofibers by immersion, on the one hand, The bonding strength between CdS and PAN nanofibers is low, and it is easy to fall off during use. On the other hand, the CdS particles obtained by the soaking method are prone to agglomeration, and the particle size is tens to hundreds of nanometers (Yang et al., Electrospinning of carbon/CdS coaxial nanofibers with photoluminescence and conductive properties, Mater Sci Eng B-Adv., 2007, 140, 48-52). However, the CdS-OH nanoparticles (5 nm) prepared by the solution growth method and PAN are jointly made into a spinning solution, and then the CdS-OH/PAN hybrid nanofibers obtained by electrospinning can not only ensure that the CdS-OH nanoparticles It is stably combined with PAN and effectively prevents the agglomeration of CdS-OH nanoparticles (Wang et al., Fabrication and characterization of electrospun CdS-OH/polyacrylonitrile hybrid nanofibers, Composites Part A, 2012, 43, 1869-1876). On this basis, carbon nanotubes (CNT) were mixed into the spinning solution to make a spinning solution containing three components of CdS-OH, CNT and PAN, and the ternary CdS- OH/CNT/PAN hybrid nanofibers. Since their discovery, CNTs have been favored by people for their excellent mechanical properties, high electrical conductivity, high chemical stability, and large specific surface area. Therefore, the addition of CNTs enables the hybrid nanofibers to ensure the high specific surface area of the material, and the low-size and uniform distribution of CdS-OH nanoparticles. The separation of photogenerated electron-hole pairs further improves the photocatalytic efficiency. The present invention uses CdCl ₂ , Na ₂ S, ME, CNT and PAN as raw materials to prepare ternary CdS-OH/CNT/PAN hybrid nanofibers by combining solution growth method and electrospinning method. Compared with organic-inorganic hybrid materials, hybrid nanofibers have high specific surface area and aspect ratio, low size and uniform distribution of CdS-OH nanoparticles, electrical conductivity of CNT, and suppression of hybridization of photogenerated electron-hole pairs. sex. Moreover, the hybrid nanofibers are easier to recycle after the photocatalytic reaction.

Contents of the invention

The invention combines a solution growth method and an electrospinning method to prepare CdS-OH/CNT/PAN hybrid nanofibers which have photocatalytic degradation performance and are easy to recycle. The average diameter of the CdS-OH/CNT/PAN hybrid nanofibers prepared by this method is 310 nm, and the average diameter of the CdS-OH nanoparticles inside the hybrid nanofibers is about 5 nm. The diameter of nanofibers can be achieved by adjusting the concentration of the spinning solution, the diameter of the nozzle, and the distance between the nozzle and the receiver.

The technical scheme adopted for realizing the object of the present invention is:

(1) Preparation of CdS-OH/DMF suspension

① Under magnetic stirring, add 30 mL of N,N-dimethylformamide (DMF) solution dropwise to 3 mL of CdCl ₂ aqueous solution, and stir for 10 min to obtain A solution.

The DMF solution contains 5 mmol of 2-mercaptoethanol, and the CdCl ₂ aqueous solution contains 2.5 mmol of CdCl ₂ .

②Add 3 mL of Na ₂ S aqueous solution dropwise to solution A, mix well, and prepare a mixed solution. At this time, the colorless and transparent mixed solution first turns yellow and gradually becomes turbid. After standing still, react at 30°C for 4-5.5 hours, the yellow solution becomes clear and transparent again, and B solution is obtained.

The Na ₂ S aqueous solution contains 1.5 mmol Na ₂ S.

③Transfer the B solution to a rotary evaporator for vacuum distillation at 85-92°C to remove water. In the process of vacuum distillation, NaCl was precipitated out of the solution because it was insoluble in DMF. Therefore, the precipitated NaCl was removed by centrifugation to obtain a clear and transparent CdS-OH/DMF suspension.

(2) Preparation of electrospinning solution

①Dissolve PAN in DMF at 65°C to make a clear solution, then add acetone and cetyltrimethylamine bromide (CTAB) into the solution to make solution C. In solution C, the mass concentration of PAN is 11%, the mass concentration of acetone is 6.1%, and the mass concentration of CTAB is 0.03%.

② Add carbon nanotubes (CNTs) to the CdS-OH/DMF suspension prepared in step (1), stir magnetically for 30 min, and sonicate in an ultrasonic oscillator for 3 hours to make a uniform black suspension D.

The mass fraction of CNT in the black suspension D is 0.004%-0.4%.

③ Slowly drop the black suspension D into solution C under magnetic stirring, stir for 30 min and then sonicate in an ultrasonic oscillator for 3 hours. Obtain uniform CdS-OH/CNT/PAN spinning solution.

(3) Preparation of CdS-OH/CNT/PAN hybrid nanofibers by electrospinning

Transfer the CdS-OH/CNT/PAN spinning solution into a 10 mL syringe (the inner diameter of the syringe needle is 1 mm), using the electrospinning device, connect the positive pole of the high-voltage power supply to the syringe needle, and connect the negative pole to the flat receiver covered with aluminum foil , at a temperature of 24-30°C, a humidity of 40-60%, a power supply voltage of 12-15 kV, a distance between the needle and the receiver of 15 cm, and a spinning solution flow rate of 2.5 μL/min. , to obtain CdS-OH/CNT/PAN hybrid nanofibers.

The advantage of the CdS-OH/CNT/PAN hybrid nanofiber prepared by the present invention is:

1. The present invention adopts the combination of solution growth method and electrospinning method to prepare hybrid nanofibers, with simple process and high yield.

2. The average diameter of CdS-OH/CNT/PAN hybrid nanofibers prepared by the present invention is 310 nm, and the average diameter of CdS-OH nanoparticles is 5 nm. This preparation method effectively suppresses the agglomeration of CdS-OH nanoparticles .

3. The CdS-OH/CNT/PAN hybrid nanofiber prepared by the present invention has the characteristics of large specific surface area and good mechanical properties.

4. The recombination of photogenerated electron-hole pairs of the CdS-OH/CNT/PAN hybrid nanofiber prepared by the present invention is inhibited by CNT, which improves its high photocatalytic degradation efficiency for organic dyes, and the nanofiber is easy to recycle .

Description of drawings

Fig. 1 is a structural model diagram of the dS-OH/CNT/PAN hybrid nanofiber prepared by the method of the present invention.

In Figure 1, 1 is polyacrylonitrile (PAN); 2 is CdS nanoparticles (CdS-OH); 3 is carbon nanotubes (CNT).

Detailed ways

Example 1

(1) Preparation of CdS-OH/DMF suspension

①Under magnetic stirring, drop 30 mL of DMF solution containing 5 mmol 2-mercaptoethanol (ME) into 3 mL of aqueous solution containing 2.5 mmol CdCl ₂ and stir for 10 min to obtain A solution.

②Add 3 mL of an aqueous solution containing 1.5 mmol Na ₂ S dropwise to solution A. At this time, the colorless and transparent solution immediately turns yellow and gradually becomes turbid. After the mixed solution was reacted at 30° C. for 4 hours, the yellow solution became clear and transparent again, and solution B was obtained.

③Transfer the B solution to a rotary evaporator and carry out vacuum distillation at 85°C to remove water and a small part of DMF. After vacuum distillation, the precipitated NaCl was removed by centrifugation to obtain a clear and transparent CdS-OH/DMF suspension with a mass concentration of 1.2%.

(2) Preparation of electrospinning solution

①Dissolve 1.5 g PAN in 11.0 g DMF to make a clear solution, then add 0.8 g acetone and 0.004 g cetyltrimethylamine bromide (CTAB) into the solution to make a mass concentration of 11% PAN , 6.1% acetone, 0.03% C solution of CTAB.

② Add 0.0016 g of multi-walled carbon nanotubes (MWCNT) to 6.6 g of CdS-OH/DMF suspension with a mass concentration of 1.2%, magnetically stir for 30 min, and ultrasonicate for 3 hours in an ultrasonic oscillator to make a uniform black suspension D.

③The black suspension D was slowly added to the C solution under magnetic stirring, and after stirring for 30 min, it was sonicated in an ultrasonic oscillator for 3 hours to obtain 20 g of 7.5% PAN, 0.4% CdS-OH and 0.008% MWCNT. Uniform and stable CdS-OH/MWCNT/PAN spinning solution.

(3) Preparation of CdS-OH/MWCNT/PAN hybrid nanofibers

Transfer the CdS-OH/MWCNT/PAN spinning solution into a 10 mL syringe (the inner diameter of the needle tip of the syringe is 1 mm), using the electrospinning device, connect the positive pole of the high-voltage power supply to the needle tip of the syringe, and connect the negative pole to the flat receiver covered with aluminum foil , Electrospinning was carried out at a temperature of 30 °C and a humidity of 40%. Among them, the power supply voltage was 12 kV, the distance between the needle tip and the receiver was 15 cm, and the solution flow rate was 2.5 μL/min. CdS-OH/MWCNT/PAN hybrid nanofibers with a mass ratio of CdS-OH:MWCNT:PAN of 5:0.1:94.9 were obtained.

(4) Take 100 mg of CdS-OH/MWCNT /PAN hybrid nanofibers and put them into 100 mL of 10 mg/L methyl orange solution, stir magnetically for 50 min under the irradiation of a 500 W high-pressure mercury lamp, and measure the methyl orange in the solution. The degradation rate is 90%.

Example 2

(1) The preparation of CdS-OH/DMF suspension is the same as in Example 1

(2) Preparation of electrospinning solution

①Dissolve 1.5 g PAN in 11.0 g DMF to make a clear solution, then add 0.83 g acetone and 0.0044 g cetyltrimethylamine bromide (CTAB) into the solution to make a mass concentration composition of 11% PAN, 6.1% acetone, 0.03% CTAB solution in C.

② Add 0.008 g of MWCNT to 6.61 g of 1.2% CdS-OH/DMF suspension, magnetically stir for 30 min, and ultrasonicate for 3 hours in an ultrasonic oscillator to make a uniform black suspension D.

③ Slowly add suspension D to solution C under magnetic stirring, stir for 30 min, and then ultrasonicate for 3 hours in an ultrasonic oscillator. Obtained 20g mass concentration composition is the homogeneous and stable CdS-OH/MWCNT/PAN spinning solution of 7.5%PAN, 0.4%CdS-OH and 0.04%MWCNT.

(3) Preparation of CdS-OH/MWCNT/PAN hybrid nanofibers

Transfer the CdS-OH/MWCNT/PAN spinning solution into a 10 mL syringe (the inner diameter of the needle tip of the syringe is 1 mm), using the electrospinning device, connect the positive pole of the high-voltage power supply to the needle tip of the syringe, and connect the negative pole to the flat receiver covered with aluminum foil , Electrospinning was carried out at a temperature of 24 °C and a humidity of 60%. Among them, the power supply voltage was 15 kV, the distance between the needle tip and the receiver was 15 cm, and the solution flow rate was 2.5 μL/min. CdS-OH/MWCNT/PAN hybrid nanofibers with a mass ratio of CdS-OH:MWCNT:PAN of 5:0.5:94.5 were obtained.

(4) Take 100 mg of CdS-OH/MWCNT /PAN hybrid nanofibers and put them into 100 mL of 10 mg/L methyl orange solution, stir magnetically for 50 min under the irradiation of a 500 W high-pressure mercury lamp, and measure the methyl orange in the solution. The degradation rate is 94%.

Example 3

(1) The preparation of CdS-OH/DMF suspension is the same as in Example 1

(2) Preparation of electrospinning solution

①Dissolve 1.5 g PAN in 11.0 g DMF to make a clear solution, then add 0.83 g acetone and 0.0044 g cetyltrimethylamine bromide (CTAB) into the solution to make a mass concentration composition of 11% PAN, 6.1% acetone, 0.03% CTAB solution in C.

② Add 0.008 g of single-walled carbon nanotubes (SWCNT) to 6.65 g of 1.2% CdS-OH/DMF suspension, magnetically stir for 30 min, and ultrasonicate for 3 hours in an ultrasonic oscillator to make a uniform black suspension D.

③ Slowly add suspension D to solution C under magnetic stirring, stir for 30 min, and then ultrasonicate for 3 hours in an ultrasonic oscillator. Obtained 20g mass concentration composition is the homogeneous and stable CdS-OH/SWCNT/PAN spinning solution of 7.5%PAN, 0.4%CdS-OH and 0.04%MWCNT.

(3) Preparation of CdS-OH/SWCNT/PAN hybrid nanofibers

Transfer the CdS-OH/SWCNT/PAN spinning solution into a 10 mL syringe (the inner diameter of the needle tip of the syringe is 1 mm), using the electrospinning device in the laboratory, the positive pole of the high-voltage power supply is connected to the needle tip of the syringe, and the negative pole is connected to the flat plate covered with aluminum foil. With the receiver attached, electrospinning was performed at a temperature of 27 °C and a humidity of 50%. Among them, the power supply voltage was 12 kV, the distance between the needle tip and the receiver was 15 cm, and the solution flow rate was 2.5 μL/min. CdS-OH/SWCNT/PAN hybrid nanofibers with a mass ratio of CdS-OH:SWCNT:PAN of 5:1:94.0 were obtained.

(4) Take 100 mg CdS-OH/SWCNT /PAN hybrid nanofibers into 100 mL of 10 mg/L methyl orange solution, stir magnetically for 50 min under the irradiation of a 500 W high-pressure mercury lamp, and measure the methyl orange in the solution. The degradation rate is 97%.

Claims (6)

1.CdS/ the preparation method of carbon nanotube/polypropylene nitrile Hybrid nanofibers is characterized in that:

(1) preparation of CdS-OH/DMF suspension

1. under magnetic agitation, 30 mL DMF solution are dropwise joined the CdCl of 3 mL ₂The aqueous solution in, stir 10min, obtain A solution;

2. with 3 mLNa ₂The aqueous solution of S dropwise joins in the A solution, and mixing is mixed with mixed solution, leaves standstill, and 30 ℃ of lower reactions 4～5.5 hours, obtains B solution;

3. B solution is transferred to and under 85～92 ℃, carried out decompression distillation on the Rotary Evaporators, except anhydrating the centrifugal CdS-OH/DMF suspension that obtains clear;

(2) preparation of electrostatic spinning liquid

1. polyacrylonitrile is dissolved in the solution of making clarification among 65 ℃ of DMF, afterwards acetone and cetrimonium bronmide is added in the solution, mixing is made C solution;

2. CNT is joined in the CdS-OH/DMF suspension of step (1) preparation, magnetic agitation 30 min, and in ultrasonator ultrasonic 3 hours, make uniform black suspension D;

3. under magnetic agitation, black suspension D is slowly splashed in the C solution, stirred behind 30 min in ultrasonator ultrasonic 3 hours, obtain CdS-OH/ CNT/PAN spinning solution;

(3) electrostatic spinning prepares Hybrid nanofibers

The CdS-OH/CNT/PAN spinning solution is transferred in the syringe of 10 mL and carried out electrostatic spinning, obtain CdS-OH/ carbon nanotube/polypropylene nitrile Hybrid nanofibers.

2. the preparation method of a kind of CdS according to claim 1/carbon nanotube/polypropylene nitrile Hybrid nanofibers is characterized in that containing in the described DMF solution 2 mercapto ethanol of 5 mmol, described CdCl ₂The aqueous solution in contain the CdCl of 2.5 mmol ₂

3. the preparation method of a kind of CdS according to claim 1/carbon nanotube/polypropylene nitrile Hybrid nanofibers is characterized in that described Na ₂Contain 1.5 mmol Na in the aqueous solution of S ₂S.

4. the preparation method of a kind of CdS/ carbon nanotube/polypropylene nitrile Hybrid nanofibers according to claim 1 is characterized in that PAN in the described C solution, and mass concentration is 11%, and acetone quality concentration is that 6.1%, CTAB mass concentration is 0.03%.

5. the preparation method of a kind of CdS/ carbon nanotube/polypropylene nitrile Hybrid nanofibers according to claim 1, the mass fraction that it is characterized in that CNT among the described black suspension D is 0.004%～0.4%.

6. the preparation method of a kind of CdS/ carbon nanotube/polypropylene nitrile Hybrid nanofibers according to claim 1, it is characterized in that described electrostatic spinning, the internal diameter of the syringe needle that adopts is 1mm, temperature is 24～30 ℃, humidity is 40～60%, supply voltage is 12～15 kV, and the distance of syringe needle and receiver is 15 cm, and the spinning solution flow velocity is 2.5 μ L/min.

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