CN105968347B - The preparation method of N substitution carboxyls polyaniline/cadmium sulfide quantum dot composite material - Google Patents

Abstract

A preparation method of N-substituted carboxyl polyaniline grafted cadmium sulfide quantum dot composite material, the method uses N-phenylglycine as a monomer, and generates a cadmium-containing precursor by introducing a cadmium source in its in-situ polymerization system , and then by introducing a sulfur source, using the nucleation mechanism between cadmium and sulfur to prepare chemically grafted N-substituted carboxypolyaniline cadmium sulfide quantum dot composites. Compared with cadmium sulfide and polyaniline, the electronic transport rate of the composite material prepared by the method of the present invention is greatly improved, the light corrosion resistance of cadmium sulfide is improved, photoelectric conversion and photocatalytic degradation of organic dyes can be performed under visible light, The solubility and stability of the material are improved. The obtained composite material can be applied in photocatalyst, sensor, solar cell and other fields.

Description

Preparation method of N-substituted carboxyl polyaniline/cadmium sulfide quantum dot composite material

technical field

The invention relates to a preparation method of an N-substituted carboxyl polyaniline/cadmium sulfide quantum dot composite material, which belongs to the technical field of conductive polymer materials.

Background technique

Energy shortage and environmental pollution are the most urgent problems facing today. All countries in the world are looking for an emerging industry that can effectively deal with the energy crisis, relieve environmental pressure, develop a low-carbon economy, and achieve sustainable development. Due to its cleanliness, safety, convenience, and high efficiency, solar photovoltaics are flourishing all over the world, and are known as a sunrise industry that welcomes the arrival of the new energy era. At the same time, with the gradual maturity of organic solar cells and photocatalytic degradation technologies, the preparation of photoactive materials by polymer composite semiconductor quantum dots has become more and more favored by researchers.

As a conductive polymer material, polyaniline is a new type of high-efficiency electron and hole transfer material. Because of its simple synthesis, unique doping mechanism, good conductivity, and high specific capacitance, it has many advantages in supercapacitor electrode materials, photocatalysts, etc. However, the rigid structure of polyaniline makes its dissolution processing performance poor, and it is difficult to perform photoelectric conversion under visible light. In addition, cadmium sulfide (CdS) is an excellent N-type semiconductor material with a bandgap of 2.42eV, an electron mobility of 2×10 ^-2 m ^2. V ^-1. s ^-1 , and a unique photoelectrochemical It has a very attractive application prospect in the field of solar cells and optoelectronic equipment, and the optical properties of cadmium sulfide semiconductor materials are closely related to their own grain size and shape, so preparing cadmium sulfide particles with a certain particle size has The basis of optical properties. However, the fly in the ointment is that the nucleation rate of cadmium sulfide is very fast, and it is easy to agglomerate, and cadmium sulfide is easy to be photocorroded under visible light. These defects have a certain impact on the further application of cadmium sulfide. Therefore, whether it is conductive polyaniline material or cadmium sulfide material used alone in photoelectric conversion devices, there are deficiencies and defects. In order to make full use of the advantages of the two materials and exert their synergistic effect, cadmium sulfide quantum dots and polyaniline are compounded to prepare A polyaniline/cadmium sulfide quantum dot composite photoelectric material capable of high-speed photoelectric conversion under visible light and good cycle stability has very important practical significance.

In order to prepare polyaniline cadmium sulfide quantum dot composite materials, researchers at home and abroad have made many attempts. Because polyaniline itself has a conjugated large π electron structure, it can undergo π-π stacking with the 3d _5/2 orbital of cadmium. In addition, the negatively charged N and positively charged Cd ions in the polyaniline chain can pass electrostatic interaction to connect. In many studies, stacking by π-π stacking, electrostatic interaction and hydrogen bonding is the most common preparation mechanism, including: in-situ polymerization, electrochemical polymerization, sol-gel method, and self-assembly method. The polyaniline cadmium sulfide composite material prepared in this way has a good photoelectric effect under visible light and can control the morphology of cadmium sulfide to a certain extent. However, the composite materials prepared by these methods have relatively large interfacial distance due to the weak force between different components, poor separation effect of electrons and holes, and the purity of the product is not high, and the photocorrosion resistance is poor. In order to promote the rapid movement of electrons between the two materials, and at the same time improve the defect that cadmium sulfide is prone to photocorrosion under visible light, a common improvement method is to form a core-shell structure of cadmium sulfide and polyaniline, and wrap cadmium sulfide quantum dots It can be used as a protective layer in organic conductive polyaniline, but this method will reduce the light conversion efficiency and cycle stability of cadmium sulfide.

In summary, it is very important to develop polyaniline cadmium sulfide quantum dot composite materials with high photoelectric conversion efficiency and light corrosion resistance, and to find a cost-effective and universally applicable method for preparing such composite materials. of.

Contents of the invention

The purpose of the present invention is to provide a method for preparing a carboxyl-modified polyaniline cadmium sulfide quantum dot composite material with strong light corrosion resistance and excellent photoelectric conversion performance.

Technical scheme of the present invention is:

The present invention adopts a two-step synthesis method. First, in-situ polymerization is carried out in a solution containing N-phenylglycine and cadmium ions to obtain a cadmium-containing N-substituted carboxyl polyaniline precursor; Mechanism of intermediate nucleation to make cadmium sulfide quantum dots grafted onto the polymer to form N-substituted carboxyl polyaniline cadmium sulfide quantum dot composites.

The method step of preparing N-substituted carboxyl polyaniline cadmium sulfide quantum dot composite material of the present invention is as follows:

Weigh a certain amount of N-phenylglycine and cadmium source and dissolve it in a certain volume of HCl solution with a certain concentration, and form a uniform mixed solution by ultrasonic dispersion, which is recorded as solution A; then dissolve the oxidant ammonium persulfate in a certain concentration A homogeneous mixed solution is formed in the HCl solution, which is denoted as B solution; slowly drop B solution into A solution placed in an ice-water bath; after reacting for a certain period of time, continue stirring at room temperature for a certain period of time, and wash the product with water and ethanol Multiple times, the product was dried in a vacuum oven to obtain a cadmium-containing composite material precursor; finally, the sulfur source was slowly introduced in an ice-water bath without light, and reacted for a certain period of time, using the nucleation mechanism between the sulfur source and the cadmium source. The N-substituted carboxyl polyaniline cadmium sulfide composite material is obtained.

The nominal polymerization reaction formula of N-substituted carboxyl polyaniline cadmium sulfide quantum dot composite material is as follows:

The composite material is light purple in aqueous solution, which is different from the color of the precursor (dark green), indicating the formation of a polymer.

The FTIR, UV-Vis, XRD spectrum and XPS techniques have successfully confirmed the chemical grafting of cadmium sulfide quantum dots to the structure of N-substituted carboxyl polyaniline. The morphology of the material has been studied by SEM and TEM techniques, and N-substituted Carboxylated polyaniline cadmium sulfide composites have a point-like structure closely attached to the fiber structure, which retains the integrity and regularity of the polyaniline and cadmium sulfide structures. Studies have shown that cadmium sulfide grafted on N- Substituting carboxylated polyaniline polymer chains forms a composite material with stronger interactions.

In the present invention, the cadmium-containing precursor is prepared in a strong acid environment, and the hydrochloric acid environment improves the reactivity of the monomer, and the polymerization reaction will become very slow without the presence of acid. In the present invention, hydrochloric acid should keep its hydrogen ion concentration to be 0.5 ~ 2mol/L.

In the present invention, since the carboxyl group on the N-phenylglycine is the reactive point, the formation of the precursor of cadmium has a certain dependence relationship with the concentration of the carboxyl group, so in the present invention, the N-phenylglycine and cadmium ion The optimal molar ratio is 1:0.5~1:4.

In the present invention, the concentration of hydrochloric acid in the hydrochloric acid aqueous solution is 0-6mol/L.

In the present invention, the molar ratio of the cadmium-containing precursor to the sulfur source has a great influence on the generation of cadmium sulfide quantum dots, and finally directly affects the content of cadmium sulfide in the composite material. Therefore, in the present invention, the molar ratio of the cadmium-containing precursor to the sulfur source is 1:0.2-1:5, most preferably 1:0.5-1:3.

Due to the nucleation process between the precursor of cadmium and the sulfur source, time and temperature have a greater impact on nucleation, too low or too high reaction temperature and time are not conducive to reaction, so in the present invention, the polymerization temperature The temperature is preferably 0-10°C, and the liquid phase reaction time is 0.5-3h.

In the present invention, known methods are used to carry out post-treatments such as separation and purification of the composite material product. The treatment includes removing unreacted monomers, by-products of the reaction, oligomers of the reaction, and residual oxidants remaining in the reaction mixture. The processing steps are: centrifugation, organic solvent washing, deionized water washing, organic solvent washing, precipitation and drying.

The beneficial effects of the present invention are: the chemical oxidation polymerization method of the present invention can be used to prepare N-substituted carboxy polyaniline cadmium sulfide quantum dot composite material, the method of the present invention is economical and effective, and has universal applicability, and the introduction of carboxyl groups has a great effect on the dispersion of quantum dots play an important role. The interfacial force of the N-substituted carboxyl polyaniline cadmium sulfide quantum dot composite material prepared by the present invention is significantly strengthened, and the defects of cadmium sulfide, which are easy to agglomerate and extremely easy to be corroded by light, are greatly improved, and in the process of photoelectric conversion , with high cycle stability.

The N-substituted carboxyl polyaniline cadmium sulfide quantum dot composite material obtained in the invention can be used as a conductive polymer material in the fields of photocatalysts, sensors, solar cells and the like.

Description of drawings

Fig. 1 is a kind of chemical oxidation preparation method flowchart of N-substituted carboxy polyaniline cadmium sulfide quantum dot composite material of the present invention;

Figure 2 is the infrared spectrum of the chemically grafted and mechanically blended N-substituted carboxypolyaniline cadmium sulfide quantum dot composite material (NPANI/CdS) and a single material;

In the figure a is the infrared diffraction spectrum of pure N-substituted carboxylic acid polyaniline (NPNAI), b is the infrared diffraction spectrum of simple mechanically blended polyaniline cadmium sulfide quantum dot composites, and c is the polyaniline cadmium sulfide quantum dot composite material. Infrared diffraction spectra of dot composites. The characteristic peaks of the infrared spectrum of pure NPANI respectively represent: the absorption peaks with wavelengths of 3447 cm ^-1 and 1665 cm ^-1 correspond to the stretching vibration of NH and the stretching vibration of carboxyl C=O in its structure; the wavelength is 1557 cm ^-1 The absorption peaks at 1480cm -1 and 1480cm ^-1 respectively correspond to the C=C resonance absorption in the quinone ring and the benzene ring in the structure; the absorption peak at 801cm ^-1 corresponds to the para-disubstituted structure of the benzene ring. Comparing the infrared characteristic absorption peak of NPANI/CdS with that of NPANI, it is found that compared with the peak of OH stretching vibration that appears in NPANI, there is almost no peak on NPANI/CdS, indicating that the H on the OH bond on the composite material is absorbed by other atomic substitution; and the stretching vibration peak of the C=O bond that appeared at 1665 cm ^-1 on NPANI also red-shifted to 1684 cm ^-1 on the composite material, indicating that the existence of Cd ²⁺ destroyed the formation of benzene ring, amino group and carboxyl group The conjugated system of the system reduces the density of the electron cloud of the system, making these functional groups redshift. Comparing the OH stretching vibration peaks and C=O bond stretching vibration peaks on the simple mechanically blended NPANI/CdS blend material with those on pure NPANI, it is found that the peak positions corresponding to these functional groups are completely consistent, and there is no The offset phenomenon again shows that the CdS particles on the NPANI/CdS composite are connected with NPANI by chemical grafting.

Fig. 3 is the XRD spectrogram of chemically grafted N-substituted polyaniline cadmium sulfide quantum dot composite material and a single material;

Curve a in the figure is the X-ray diffraction pattern of pure NPANI, and curve b is the X-ray diffraction pattern of NPANI/CdS composite material. Because NPANI is a non-crystalline polymer material, it is difficult to see its diffraction angle from the X-ray diffraction pattern. Therefore, in Figure a, only a large diffraction peak appears around 21°. Comparing figure a with figure b, it is not difficult to see that the X-ray diffraction pattern of the composite material is obviously different from that of the NPANI material alone. The spectrum of the composite material also has diffraction angles of 25.6 ^o and 42.1 ^o on the basis of NPANI , 54.1 ^o These three diffraction peaks correspond to the three crystal planes of CdS in (111), (220), (311), which proves the existence of CdS material in the composite material.

Fig. 4 chemically grafted and mechanically mixed N-substituted carboxyl polyaniline cadmium sulfide quantum dot composite material and the fluorescence spectrum of a single material;

In the spectrum of cadmium sulfide, there are two broad and strong absorption peaks around 480cm ^-1 and 540cm ^-1 , which correspond to the intrinsic exciton emission and trap emission of cadmium sulfide respectively; Cadmium sulfide, mechanically mixed NPANI/CdS materials and covalently bonded NPANI/CdS materials also have characteristic peaks around 480cm ^-1 and 540cm ^-1 , but their intensity has a large weakening, which proves that due to the high-speed electron acceptor In the presence of NPANI, the electrons generated by cadmium sulfide under visible light are quickly conducted to NPANI, which inhibits the rapid recombination of electrons and holes in cadmium sulfide, and at the same time, the electrons are quenched due to the transfer of photoelectrons, which greatly weakens the sulfide Cadmium trap emitters. The fluorescence intensity of the composite material through chemical grafting has a greater weakening, which further proves that NPANI and cadmium sulfide are connected together through chemical grafting, and this effect can reduce the distance between interfaces and accelerate the separation of photoelectrons and holes. .

Fig. 5 is the XPS spectrogram of the N-substituted carboxyl polyaniline cadmium sulfide quantum dot composite material of chemical grafting;

It can be seen from the figure that both materials contain three elements, C, N, and O. Compared with the XPS spectrum of NPANI, the composite material NPANI/CdS exhibits Cd3d _5/2 and S Two new peaks at _2p indicate that CdS particles have successfully existed on NPANI. In addition, since the C/O ratios in NPANI and NPANI-CdS materials are 4.39 and 4.31, respectively, the two are basically the same, which further verifies that CdS mainly reacts with the carboxyl groups in NPANI, thereby strengthening the interfacial interaction between NPANI and CdS.

Fig. 6 is the O _1s XPS peak spectrum of chemically grafted N-substituted carboxyl polyaniline cadmium sulfide quantum dot composite material and NPANI;

Figure 6(a) and Figure 6(b) are the O _1s split peak spectra of NPANI and CdS/NPANI composite materials, respectively, and Figure 6(c) and Figure 6(d) are the characteristics of Cd and S in the composite materials The absorption peak further proves that there is CdS in it.

Compared with Figure 6(a), the new peak at 532.30eV in Figure 6(b) is the O-Cd structure, and in addition, the proportion of O-H structure at 532.19 in Figure 6(b) is higher than that in Figure 6(a ) has a certain decrease, which proves that Cd has successfully grafted with NPANI. Since it is observed in Figure 5 that cadmium sulfide is contained in the composite material, this further verifies that in the CdS/NPANI composite material, CdS and NAPNI are connected by chemical grafting.

Fig. 7 is the TEM and HRTEM spectrogram of the N-substituted carboxyl polyaniline cadmium sulfide quantum dot composite material of chemical grafting;

Figure 7(a) is the TEM image of pure NPANI, Figure 7(b) is the TEM image of the NPANI/CdS composite, Figure 7(c) is the TEM image of the NPANI/CdS composite at a larger magnification, Figure 7( d) Diagram of interplanar spacing of CdS particles in the composite material under HR-TEM. It can be observed from the figure that N-substituted carboxypolyaniline (figure a) is a uniform fibrous strip structure with a length of several hundred nanometers and a width of 35-55nm, and the dark color in the figure is due to the free coiling of the long chain of NPANI Links make the sample thickness darker. Figure 7(b)(c)(d) are the TEM images of CdS/NPANI under different magnifications. From Figure 7(b)(c), it can be clearly observed that a certain amount of The dark spots of different shades correspond to CdS particles, and the particle size of the CdS particles is between 5-30 nanometers, and there is no obvious agglomeration phenomenon, which further verifies that there are CdS particles on the NPANI chain, and due to the existence of NPANI , to a certain extent inhibits the agglomeration of CdS; Figure 7(d) is a NPANI/CdS high-power transmission electron microscope (HR-TEM) photo, and two layers of different light and dark structures can be observed, among which the NPANI layer with an amorphous structure is at the edge, The dark part in the middle has a certain regular arrangement corresponding to the hexagonal crystal form of nano-cadmium sulfide particles, and the lattice spacing before photocatalysis is calculated to be 0.271nm.

Figure 8 is the TG spectrum of the chemically grafted N-substituted carboxyl polyaniline cadmium sulfide quantum dot composite material and a single material

Figure 8(a) is the thermogravimetric diagram of N-AN monomer at 800 °C, Figure 8(b) is the thermogravimetric diagram of pure NPANI at 800 °C, and Figure 8(c) is the NPANI/CdS composite The thermal weight loss diagram at 800 °C, Fig. 8(d) is the overlaid diagram of the thermal loss of the three substances a, b, and c. From Figure 8(a), it can be found that the monomer N-AN has been completely decomposed before 600 °C. Before 300°C, the thermal weight loss in Figure 8(a) shows a downward trend almost in a straight line, which is the bond breaking temperature of -COOH and -NH2 in the monomer, and around 400°C is the temperature of the benzene ring -C=C- on the monomer Bond breaking temperature.

Comparing Figure 8(a) and Figure 8(b), we find that the thermal weight loss rate of polymerized NPANI before the temperature rises to 300°C is much lower than that of N-AN monomer. It shows that the thermal stability of polymerized NPANI is stronger, which makes the decomposition temperature of -COOH and -NH2 functional groups increased. At the same time, the occurrence of the polymerization reaction also made the bond breaking temperature of -C=C- on NPANI rise from 400 °C of the monomer to 497 °C, and the temperature at which the entire polymer was completely decomposed, due to the formation of the benzene ring conjugated system , also increased by about 100°C, and the final complete decomposition temperature of pure NPANI in the system also reached 680°C.

From the TGA curves of Figure 8(b) and Figure 8(c), we can intuitively see that NPANI has been completely decomposed when the temperature reaches 680 °C, while the composite NPANI/CdS has 22% when the temperature reaches 800 °C. About % of the substance has not been completely decomposed. This is because the composite material contains cadmium. The decomposition temperature of cadmium is very high, and the temperature of 800 ° C cannot decompose it. Before the temperature rises to 300 °C, the thermogravimetric curve of NPANI/CdS composite is relatively smooth compared with that of pure NPANI, which is due to the interaction between CdS on the composite and -COOH and -NH2 on the benzene ring , so that their stability is enhanced, so they are not easy to decompose, which proves that there is a certain improvement in the stability of the composites due to the presence of cadmium sulfide.

Fig. 9 is the HRTEM spectrogram before and after photocatalysis of chemically grafted N-substituted carboxyl polyaniline cadmium sulfide quantum dot composite;

In the figure, Figure 9(a) is the crystal structure of CdS particles before photocatalysis of NPANI/CdS composite material under HR-TEM; Figure 9(b) is the CdS particle after photocatalysis of NPANI/CdS composite material under HR-TEM crystal structure diagram. It can be seen from the figure that the lattice spacing of CdS particles of the NPANI/CdS composite material before photocatalysis is 0.271nm, and the lattice spacing after one cycle of light irradiation is 0.272nm. Before and after illumination, the lattice spacing of CdS on the composite material hardly changed, indicating that the crystal structure of CdS particles protected by NPANI was not destroyed after illumination. HR-TEM more intuitively shows that -COOH on NPANI plays a very good role in stabilizing and protecting CdS particles, and improves the photocorrosion resistance of cadmium sulfide.

Detailed ways

Example 1:

This example will illustrate the method of the present invention to generate a cadmium-containing precursor by in-situ polymerization with a molar ratio of N-phenylglycine and cadmium acetate of 1:2, and then in an ice-water bath, use the cadmium precursor and sodium sulfide nonahydrate The molar ratio is 1:1, the reaction time is 2h, and it is realized according to the reaction path of two-step synthesis.

Weigh 0.756g of N-phenylglycine and 2.66g of cadmium acetate and dissolve in 40ml of HCl solution with a concentration of 1M, and ultrasonicate for 30min until the mixed solution is dispersed to form a homogeneous solution, labeled as A; weigh 1.427g of ammonium persulfate and dissolve in In 60ml of HCl solution with a concentration of 1M, ultrasonically disperse for 5 minutes to form a uniform solution, labeled as B; in an ice-water bath, keep liquid A continuously stirring, slowly drop liquid B into liquid A, react for 6 hours, and then Leave it for 18 hours, after the reaction, let it stand and centrifuge, and wash it several times with water and absolute ethanol to remove the oligomers and inorganic impurities generated in the reaction, then put it in an oven and dry it at 60°C for 24 hours for later use; then weigh Dissolve 0.1g of the above-mentioned dried cadmium-containing precursor sample in 50ml of deionized water, ultrasonically disperse for 30min to form a homogeneous solution labeled C, keep stirring in an ice-water bath without light, and then take 2.4g of sodium sulfide nonahydrate to dissolve Fully disperse the labeled D in 50ml of deionized water, slowly drop the D solution into the C solution, react for 2 hours, let it stand for centrifugation and wash it with water several times to remove excess inorganic impurities, and dry it in an oven at 60°C.

The N-substituted carboxyl polyaniline cadmium sulfide quantum dot composite material prepared by this embodiment can be better dispersed in water, wherein the content of cadmium sulfide is 12.89%, and the photocatalytic degradation of organic dye rhodamine B can reach 80%. High stability, the light corrosion resistance of cadmium sulfide has been greatly improved.

FTIR, UV-Vis, XRD spectroscopy and XPS technology successfully confirmed that the cadmium sulfide quantum dots are bonded to the structure of polyaniline, and the surface morphology of the material was found by SEM and TEM technology. The cadmium composite material is a point-like structure closely attached to the fiber structure. This shape retains the integrity and regularity of the N-substituted carboxypolyaniline and cadmium sulfide structure. It is proved by testing that the N-substituted carboxypolyaniline It is well connected with cadmium sulfide through grafting to form a composite material.

Example 2

This example will illustrate that the molar ratio of N-phenylglycine and cadmium acetate is 1:2 in the method of the present invention to generate a cadmium-containing precursor through in-situ polymerization, and then in an ice-water bath, the cadmium precursor and nonahydrate sulfide The sodium molar ratio is 1:0.5, the reaction time is 2h, and the reaction path of the two-step synthesis is realized.

Weigh 0.756g of N-phenylglycine and 2.66g of cadmium acetate and dissolve in 40ml of HCl solution with a concentration of 1M, and ultrasonicate for 30min until the mixed solution is dispersed to form a homogeneous solution, labeled as A; weigh 1.427g of ammonium persulfate and dissolve in In 60ml of HCl solution with a concentration of 1M, ultrasonically disperse for 5 minutes to form a uniform solution, labeled as B; in an ice-water bath, keep liquid A continuously stirring, slowly drop liquid B into liquid A, react for 6 hours, and then Leave it for 18 hours, after the reaction, let it stand and centrifuge, and wash it several times with water and absolute ethanol to remove the oligomers and inorganic impurities generated in the reaction, then put it in an oven and dry it at 60°C for 24 hours for later use; then weigh Dissolve 0.1g of the above dried cadmium-containing precursor sample in 50ml of deionized water, ultrasonically disperse for 30min to form a uniform solution labeled C, keep stirring in an ice-water bath without light, and then take 1.2g of sodium sulfide nonahydrate to dissolve Fully disperse the labeled D in 50ml of deionized water, slowly drop the D solution into the C solution, react for 2 hours, let it stand for centrifugation and wash it with water several times to remove excess inorganic impurities, and dry it in an oven at 60°C.

The N-substituted carboxyl polyaniline cadmium sulfide quantum dot composite material prepared by this embodiment can be dissolved in water preferably, wherein the content of cadmium sulfide is 5.6%, and the photocatalytic degradation of the organic dye rhodamine B can reach 53%, and The cycle stability is high, and the photocorrosion resistance of cadmium sulfide has been greatly improved.

Example 3

This example will illustrate that the molar ratio of N-phenylglycine and cadmium acetate is 1:2, and the cadmium-containing precursor is generated by in-situ polymerization, and then in an ice-water bath, the molar ratio of cadmium acetate and sodium sulfide nonahydrate is The ratio is 1:1, the reaction time is 0.5h, and it is realized according to the reaction path of two-step synthesis.

Weigh 0.756g of N-phenylglycine and 2.66g of cadmium acetate and dissolve in 40ml of HCl solution with a concentration of 1M, and ultrasonicate for 30min until the mixed solution is dispersed to form a homogeneous solution, labeled as A; weigh 1.427g of ammonium persulfate and dissolve in In 60ml of HCl solution with a concentration of 1M, ultrasonically disperse for 5 minutes to form a uniform solution, labeled as B; in an ice-water bath, keep liquid A continuously stirring, slowly drop liquid B into liquid A, react for 6 hours, and then Leave it for 18 hours, after the reaction, let it stand and centrifuge, and wash it several times with water and absolute ethanol to remove the oligomers and inorganic impurities generated in the reaction, then put it in an oven and dry it at 60°C for 24 hours for later use; then weigh Dissolve 0.1g of the above-mentioned dried cadmium-containing precursor sample in 50ml of deionized water, ultrasonically disperse for 30min to form a homogeneous solution labeled C, keep stirring in an ice-water bath without light, and then take 2.4g of sodium sulfide nonahydrate to dissolve Fully disperse the label D in 50ml of deionized water, slowly drop the D solution into the C solution, react for 0.5h, let it stand for centrifugation and wash it with water several times to remove excess inorganic impurities, and dry it in an oven at 60°C .

The N-substituted carboxyl polyaniline cadmium sulfide quantum dot composite material prepared by this embodiment can be dissolved in water preferably, wherein the content of cadmium sulfide is 6.71%, and the photocatalytic degradation of organic dye rhodamine B can reach 62%, The cycle stability is high, and the photocorrosion resistance of cadmium sulfide has been greatly improved.

Examples 4 to 8 will illustrate the influence of changing the molar ratio of N-phenylglycine to cadmium acetate in the present invention on the content of cadmium sulfide in the composite material and the photocatalytic degradation efficiency.

Example 4:

Repeat Example 1, but the molar ratio of N-phenylglycine to cadmium acetate is 1:0.5, the content of cadmium sulfide in the composite material is 5.91%, and the photocatalytic degradation of the organic dye rhodamine B can reach 57%.

Example 5:

Repeat Example 1, but the molar ratio of N-phenylglycine to cadmium acetate is 1:1.5, and the content of cadmium sulfide in the obtained composite material is 9.87%, and the photocatalytic degradation of the organic dye rhodamine B can reach 71%.

Embodiment 6:

Repeat Example 1, but the molar ratio of N-phenylglycine to cadmium acetate is 1:2.5 to obtain a composite material in which the content of cadmium sulfide is 12.90%, and the photocatalytic degradation of the organic dye rhodamine B can reach 80%.

Embodiment 7:

Repeat Example 1, but the molar ratio of N-phenylglycine to cadmium acetate is 1:3.5, and the content of cadmium sulfide in the obtained composite material is 12.91%, and the photocatalytic degradation of the organic dye rhodamine B can reach 80%.

Embodiment 8:

Repeat Example 1, but the mol ratio of N-phenylglycine and cadmium acetate is 1:4, obtains composite material wherein the content of cadmium sulfide is 12.92%, photocatalytic degradation organic dye Rhodamine B can reach 80%

Embodiment 9～10:

Examples 7-9 will illustrate the influence of different molar ratios of cadmium acetate and sodium sulfide nonahydrate in the present invention on the content of cadmium sulfide in the composite material and the photocatalytic degradation efficiency.

Embodiment 9:

Repeat Example 2, but make the molar ratio of the precursor of cadmium to sodium sulfide nonahydrate 1:1.5, the content of cadmium sulfide in the obtained composite material is 12.90%, and the photocatalytic degradation of the organic dye rhodamine B can reach 80%.

Example 10:

Repeat Example 2, but the molar ratio of the precursor of cadmium to sodium sulfide nonahydrate is 1:2.5, the content of cadmium sulfide in the obtained composite material is 12.81%, and the photocatalytic degradation of the organic dye rhodamine B can reach 79.5%.

Embodiment 11～14:

Example 11-Example 14 will illustrate the influence of different vulcanization reaction times in the present invention on the content of cadmium sulfide in the composite material and the photocatalytic degradation efficiency.

Example 11:

Repeat Example 3, but the vulcanization reaction time is 1h, the content of cadmium sulfide in the obtained composite material is 8.91%, and the photocatalytic degradation of the organic dye rhodamine B can reach 69%.

Example 12:

Repeat Example 3, but the vulcanization reaction time is 1.5h, the content of cadmium sulfide in the obtained composite material is 10.35%, and the photocatalytic degradation of the organic dye rhodamine B can reach 73%.

Example 13:

Repeat Example 3, but make the vulcanization reaction time 2.5h, the content of cadmium sulfide in the obtained composite material is 11.51%, and the photocatalytic degradation of the organic dye rhodamine B can reach 78%.

Example 14:

Repeat Example 3, but make the vulcanization reaction time 3h, the content of cadmium sulfide in the obtained composite material is 11.33%, and the photocatalytic degradation of the organic dye rhodamine B can reach 77.6%.

Claims (6)

1. A kind of 1. preparation method of N- substitutions carboxyl polyaniline cadmium sulfide quantum dot composite material, it is characterised in that methods described Cadmium source is introduced in N- substitutes carboxyl polyaniline and obtains presoma containing cadmium, then the polyaniline sulphur of chemical graft is prepared with sulphur source reaction Cadmium quantum dot composite material；Comprise the following steps that：

   (1) a certain amount of N-phenylglycine and cadmium acetate is taken to be dissolved in HCl solution, and ultrasonic disperse forms uniform solution, mark Number it is A；

   (2) a certain amount of ammonium persulfate is taken to be dissolved in HCl solution, and ultrasonic disperse forms uniform solution, marked as B；

   (3) under the conditions of ice-water bath, keep A liquid persistently to stir, B liquid is slowly dropped into A liquid, react certain time, then normal Temperature lower reaction certain time, stand to centrifuge and simultaneously washed for several times with water and absolute ethyl alcohol, be placed in baking oven under certain temperature dry it is standby With；

   (4) it is presoma containing cadmium to take in a certain amount of (3) that product is dissolved in ultrasonic disperse in certain volume deionized water, marked as C, and It is kept stirring under ice-water bath no light, then takes a certain amount of sulphur source soluble in water fully dispersed, marked as D, D liquid is slowly dripped Enter in C liquid, react certain time, stand and filter and be washed with water for several times, and dried in baking oven.
2. 2. N- substitutes the preparation method of carboxyl polyaniline cadmium sulfide quantum dot composite material, its feature according to claim 1 It is, the optimum molar ratio of described N-phenylglycine and cadmium ion is 1:0.5~1:4.
3. 3. N- substitutes the preparation method of carboxyl polyaniline cadmium sulfide quantum dot composite material, its feature according to claim 1 It is, hydrogen ion concentration is 0.5~2mol/L in the HCl solution.
4. 4. N- substitutes the preparation method of carboxyl polyaniline cadmium sulfide quantum dot composite material, its feature according to claim 1 It is, the optimum molar ratio of the presoma containing cadmium and sulphur source is 1:0.5~1:3.
5. 5. N- substitutes the preparation method of carboxyl polyaniline cadmium sulfide quantum dot composite material, its feature according to claim 1 It is, the liquid phase reactor time of the presoma containing cadmium and sulphur source is 0.5~3h.
6. 6. N- substitutes the preparation method of carboxyl polyaniline cadmium sulfide quantum dot composite material, its feature according to claim 1 It is, the sulphur source is nine hydrated sodium sulfides；The cadmium source is cadmium acetate.