CN114405544A - Conjugated polymer loaded metal platinum nano-particles, preparation method thereof and application thereof in photocatalytic hydrogen evolution - Google Patents

Abstract

The invention discloses a conjugated polymer-supported metal platinum nanoparticle, a preparation method and an application in photocatalytic hydrogen evolution. The successful loading of Pt nanoparticles on conjugated polymers was enabled by adding DMF during the synthesis. In this process, DMF not only acts as a solvent, but also acts as a protective agent and a reducing agent, so that Pt nanoparticles can be stably supported on the polymer without adding a complexing agent. In addition, the loading of Pt nanoparticles and the D-A effect of the conjugated polymer itself are used to effectively separate the photo-generated electron-hole pairs, which not only increases the visible light response, but also improves the photocatalytic performance. The obtained material has strong Visible light photocatalytic hydrogen production performance. In addition, the preparation method has low requirements on equipment, resulting in low investment cost for mass production, which is beneficial to practical application.

Description

A conjugated polymer-supported metal platinum nanoparticle, its preparation method and its application in photocatalytic hydrogen evolution

technical field

The invention belongs to the field of catalyst preparation, and relates to a conjugated polymer-supported metal platinum nanoparticle, a preparation method thereof, and an application in photocatalytic hydrogen evolution.

Background technique

The search for renewable energy is urgently driven by the growing energy demand and the environmental hazards caused by the burning of fossil fuels. Among them, hydrogen (H ₂ ) is considered as the main alternative resource for fossil fuels because of its zero emission and high energy. Among the many conversion methods of _H2 , the utilization of sunlight-driven photocatalytic water splitting to produce _H2 has attracted great interest as a strategy to solve both environmental and energy problems.

Conjugated polymers are not only characterized by high chemical stability and tunable optoelectronic properties, but are also a new type of low-cost organic materials with high heteroatom content, and their conjugated structures can effectively promote the separation of photogenerated charge carriers. . In theory, all photocatalytic reactions are driven by charge carriers, whose behaviors can be divided into charge generation, separation, migration, and surface reactions. The efficiency of charge utilization in each step determines the overall performance of photocatalysis. The loading of noble metal cocatalysts can effectively improve the photocatalytic activity, but it is still challenging to modify conjugated polymers by loading noble metal cocatalysts.

Therefore, in order to effectively improve the photocatalytic efficiency and charge separation, how to make the noble metal cocatalysts smoothly supported on the conjugated polymer and exist stably needs further research.

In recent years, researchers have realized the loading of noble metal cocatalysts on conjugated polymers through various methods, including using the microporous structure of the polymer and the coordination bond to support palladium (Pd) or Pt, and using the coordination agent to support the Pt At the end of the polymer, the unsaturated coordination nitrogen (N) atom of the polymer is used to anchor Pt, and the Pt nanoparticles are loaded by electrostatic adsorption.

For example, the Chinese invention patent with the application number CN202010877354.X discloses a method for loading Pd or Pt onto a polymer. In the loading process, the heteropolyacid plays an important role as a coordinating agent. The microporous structure of the polymer is used to load the heteropolyacid inside the polymer, and then it forms a coordination bond with Pd or Pt, so that the Pd or Pt It can exist stably within the polymer. There is also a Chinese invention patent with an application number of CN201911243610.3, which discloses a preparation method of a polymer-supported Pt catalyst. The invention successfully realizes the loading of noble metal cocatalyst on the polymer by introducing a large molecular weight polymer on the surface of the carrier, and then using a complexing agent to load Pt on the end of the polymer to reduce steric hindrance and increase the compatibility of the system. . In addition to using the above-mentioned complexing agent, polyvinylpyrrolidone (PVP) can also be used as a complexing agent. By sonicating the mixed solution containing PVP, Pt and polymer, the Pt coordinated with PVP enters the micropores of the polymer, and the PVP is peeled off by plasma etching, so that Pt can be successfully loaded into the polymer. in polymers (ACS Appl. Nano Mater. 2021, 4, 4, 4070–4076). In addition, there is a Chinese invention patent with the application number CN201410212520.9, which discloses a preparation method of a coordination polymer-supported Pt nanocatalyst. The method first utilizes N anchoring on Pt and 4,4-bipyridine to change the electronic structure of the polymer and delocalize the charge density of the metal, thereby promoting proton adsorption. Then Pt was reduced to Pt nanoparticles stably supported on the polymer under _H2 conditions. Another example is the Chinese invention patent with the application number of CN201310457005.2, which discloses a method of using a cationic polymer to support Pt nanoparticles. The invention utilizes the evenly distributed positive charges on the surface of the cationic polymer graphene to uniformly adsorb and distribute the negatively charged chloroplatinate ions (PtCl ₆ ^2- ) on the surface of the graphene through electrostatic adsorption.

The main shortcomings of the existing technology are as follows:

(1) Most polymers do not have a microporous structure. This results in the inability of noble metal cocatalysts to be directly supported on polymers using pores.

(2) The coordination bond is relatively weak and easy to fall off. Due to the inherent properties between the noble metal cocatalyst and the polymer, there is no strong interaction between the noble metal cocatalyst and the polymer, but a large amount exists in the solution, which greatly reduces the loading.

(3) Some polymers do not have unsaturated coordination N atoms to anchor Pt. This results in the inability to support Pt on the polymer surface without adding a complexing agent.

(4) Most polymers are neutral organic molecules, and it is impossible to realize the loading of noble metal cocatalysts by electrostatic adsorption.

Based on this, it is crucial to develop a new method to achieve stable loading of noble metal cocatalysts on polymer surfaces.

SUMMARY OF THE INVENTION

In view of the deficiencies of the prior art, the present invention provides a conjugated polymer-supported metal platinum (Pt) nanoparticle, a preparation method thereof, and an application in photocatalytic hydrogen evolution. The successful loading of Pt nanoparticles on conjugated polymers was enabled by adding DMF during the synthesis. In this process, DMF not only acts as a solvent, but also acts as a protective agent and a reducing agent, so that Pt nanoparticles can be stably supported on the polymer without adding a complexing agent. In addition, the loading of Pt nanoparticles and the Donor-Accept (D-A) effect of the conjugated polymer itself are used to effectively separate photogenerated electron-hole pairs, which not only increases the visible light response, but also improves the photocatalytic performance. It has strong visible light catalytic hydrogen production performance.

In order to solve the prior art problem, the technical scheme adopted in the present invention is as follows:

A preparation method of conjugated polymer-supported metal platinum nanoparticles, comprising the following steps:

(1) Add the raw material dithiophene[3,2-B:2',3'-D]thiophene and m-chloroperoxybenzoic acid into a round-bottomed flask, add anhydrous dichloromethane, heat, cool, and perform column chromatography , and vacuum-dried to obtain DTDO;

( ₂ ) DTDO, 1,3,6,8-tetrabromopyrene, anhydrous potassium carbonate, tris(dibenzylideneacetone)dipalladium, pivalic acid, tris(dibenzylideneacetone)dipalladium, pivalic acid, tris (o-methoxyphenyl) phosphorus and anhydrous phthalate, heated, cooled, washed, and dried to obtain PyDTDO-3;

(3) Add deionized water, chloroplatinic acid, N,N -dimethylformamide ( N,N -dimethylformamide, DMF) to the PyDTDO-3 obtained above, heat, cool, wash, dry, under Ar gas atmosphere After annealing, the conjugated polymer-supported Pt photocatalytic hydrogen evolution material Pt/PyDTDO-3 is obtained.

Preferably, in step (1), the molar ratio of the raw material dithiophene[3,2-B:2',3'-D]thiophene to m-chloroperoxybenzoic acid is (1-10):(10- 20); add 20-50 mL of anhydrous dichloromethane per 1 mmol of total raw materials, wherein the total raw materials include dithiophene[3,2-B:2',3'-D]thiophene and m-chloroperoxybenzoic acid .

Preferably, in step (1), the heating temperature is 10-40 °C, and the heating time is 20-30 h; the column chromatography is performed by volume ratio (1-5): (1-5) petroleum ether : Dichloromethane is the eluent; the temperature of the vacuum drying is 20-80 ℃, and the drying time is 20-30h.

Preferably, in step (2), DTDO, 1,3,6,8-tetrabromopyrene, anhydrous potassium carbonate, tris(dibenzylideneacetone)dipalladium, pivalic acid, tris(o-methoxyphenyl) ) The molar ratio of phosphorus is: (0.1-0.8): (0.1-0.5): (1-3): (0.01-0.03): (0.1-0.5): (0.01-0.05), adding 5 per 1 mmol of total raw materials -15 mL of anhydrous phthalate, wherein the total raw materials include dithiophene [3,2-B:2',3'-D]thiophene and m-chloroperoxybenzoic acid.

Preferably, in step (2), the heating temperature is 80-150 °C, and the heating time is 60-80 h; the washing is washed with 10-30 mL deionized water; the vacuum drying temperature is 20-80 ℃, the drying time is 20-30 h.

Preferably, in step (3), the amount of PyDTDO-3 is 20-60 mg, the amount of deionized water is 5-20 mL, the amount of chloroplatinic acid is 1-5 mL, and the amount of DMF is 5-20 mL. mL; the heating temperature is 50-100 °C, and the heating time is 5-15 h; 10-30 mL deionized water is used for the washing; the vacuum drying temperature is 20-80 °C, and the drying time is 20- 30h; the temperature of the Ar gas atmosphere annealing is 80-150° C., and the annealing time is 0.5-2 h.

The conjugated polymer supported Pt photocatalytic hydrogen evolution material Pt/PyDTDO-3 prepared based on any of the above methods.

The application of the conjugated polymer supported Pt photocatalytic hydrogen evolution material Pt/PyDTDO-3 in the preparation of hydrogen evolution photocatalyst.

Beneficial effects:

Compared with the prior art, the present invention provides a conjugated polymer supported metal platinum (Pt) nanoparticle and its preparation method and its application in photocatalytic hydrogen evolution. A series of visible-light-responsive Pt/PyDYDO-3 photocatalytic materials with high activity were prepared by the method of loading on conjugated polymers. The results of photocatalytic water splitting for hydrogen production show that the visible light catalytic activity of 7% Pt/PyDYDO-3 material is significantly enhanced, and its hydrogen production rate is 2.3 times that of pure PyDYDO-3. And it has good photocatalytic cycle stability, and has certain application value in photocatalytic water splitting for hydrogen production. The photocatalytic material prepared by the preparation method has high photocatalytic efficiency, and the visible light catalytic water splitting effect is good. In addition, the preparation method has low requirements on equipment, resulting in low investment cost for mass production, which is beneficial to practical application. Specifically as follows:

(1) Compared with the prior art, there is no need to add additional complexing agents, and this method is suitable for noble metal cocatalysts without microporous structure, without unsaturated complex N atoms and neutral organic polymers , which greatly expands the scope of application of noble metal cocatalysts on the polymer surface, and has universality;

(2) The conjugated polymer-supported Pt photocatalytic material prepared by the present invention has wide light absorption and narrower band gap, in addition, the π-stacking interaction in the conjugated polymer can promote the carriers along the plane and stacking directions The migration and transfer of 7% Pt/ ^{PyDTDO -} 3 can effectively prevent the recombination of photogenerated electrons and holes, resulting in greatly improved photocatalytic activity. The pure sample PyDTDO-3 is increased by 2.3 times. In addition, the hydrogen prepared by this method is green hydrogen, which is not only environmentally friendly and pollution-free, but also has great application prospects.

Description of drawings

Figure 1 shows PyDTDO-3, 3% Pt/PyDTDOO-3, 5% Pt/PyDTDOO-3, 3% Pt/PyDTDOO-3, 5% Pt/PyDTDOO-3, X-ray diffraction patterns (XRD) of 7% Pt/PyDTDOO-3, 9% Pt/PyDTDOO-3, 7% Pt/PyDTDOO-3-DF;

Figure 2(a) is a scanning electron microscope (SEM) image of PyDTDO-3 prepared in Comparative Example 1, with a magnification of 100,000 times;

Figure 2(b) is a scanning electron microscope (SEM) image of 7% Pt/PyDTDOO-3 prepared in Example 3, with a magnification of 100,000 times;

Figure 2(c) is a scanning electron microscope (SEM) image of 7% Pt/PyDTDOO-3-DF at a magnification of 100,000 times;

Figures 2(d)-2(f) are transmission electron microscope (TEM) images of PyDTDO-3 prepared in Comparative Example 1;

Figures 2(g)-2(i) are transmission electron microscope (TEM) images of 7% Pt/PyDTDOO-3 prepared in Example 3;

Figure 3 is the PyDTDO-3, 3% Pt/PyDTDOO-3, 5% Pt/PyDTDOO-3, 3% Pt/PyDTDOO-3, 5% Pt/PyDTDOO-3, Fourier transform infrared spectra (FTIR) of 7% Pt/PyDTDOO-3, 9% Pt/PyDTDOO-3, 7% Pt/PyDTDOO-3-DF;

Fig. 4 is the X-ray electron energy spectrum of PyDTDO-3, 7%Pt/PyDTDOO-3 and 7%Pt/PyDTDOO-3-DF prepared by Comparative Example 1, Example 3 and Comparative Example 2 of the present invention (XPS -Survey);

Fig. 5 is the high-resolution XPS image of PyDTDO-3, 7%Pt/PyDTDOO-3 and 7%Pt/PyDTDOO-3-DF prepared by comparative example 1, embodiment 3 and comparative example 2 of the present invention, wherein, (a) is the high-resolution XPS O 1s spectrum, (b) is the XPS C 1s spectrum, (c) is the XPS S 2p spectrum, (d) is the XPS Pt 4f spectrum;

Figure 6 is the PyDTDO-3, 3% Pt/PyDTDOO-3, 5% Pt/PyDTDOO-3, 3% Pt/PyDTDOO-3, 5% Pt/PyDTDOO-3, UV-Vis absorption spectra (UV-Vis DRS) of 7% Pt/PyDTDOO-3, 9% Pt/PyDTDOO-3, 7% Pt/PyDTDOO-3-DF;

Figure 7 shows PyDTDO-3, 3% Pt/PyDTDOO-3, 5% Pt/PyDTDOO-3, 3% Pt/PyDTDOO-3, 5% Pt/PyDTDOO-3, Photocatalytic performance test chart of 7% Pt/PyDTDOO-3, 9% Pt/PyDTDOO-3, 7%Pt/PyDTDOO-3-DF, in which (a) is the curve change of photocatalytic hydrogen production, (b) is Hydrogen production efficiency diagram, (c) is the test diagram of the 5-cycle experiment, (d) is the XRD pattern before and after the photocatalytic reaction;

8 is the FTIR images of PyDTDO-3 and 7% Pt/PyDTDOO-3 prepared in Comparative Example 1 and Example 3 of the present invention before and after the photocatalytic reaction.

Detailed ways

The following examples may enable those skilled in the art to more fully understand the present invention, but do not limit the present invention in any way.

Example 1

Weigh 5 mmol of dithiophene[3,2-B:2',3'-D]thiophene and 15 mmol of m-chloroperoxybenzoic acid into a round-bottomed flask according to the molar ratio, add 30 mL of anhydrous dichloromethane, 20 ℃ heated for 24 h, cooled to room temperature. Column chromatography was performed with petroleum ether:dichloromethane in a volume ratio of 2:1, and DTDO was obtained by vacuum drying at 50 °C for 24 h.

Weigh 0.5 mmol of DTDO, 0.25 mmol of 1,3,6,8-tetrabromopyrene, 1.5 mmol of anhydrous potassium carbonate, 0.015 mmol of tris(dibenzylideneacetone)dipalladium, 0.3 mmol of Pivalic acid, 0.03 mmol of tris(o-methoxyphenyl)phosphorus, and 10 mL of anhydrous phthalate. Heated at 120 °C for 72 h and cooled to room temperature. It was washed with 15 mL of deionized water and dried under vacuum at 60 °C for 24 h to obtain PyDTDO-3.

Weigh 40 mg of PyDTDO-3, add 10 mL of deionized water, 1.2 mL of chloroplatinic acid, and 10 mL of DMF, heat at 70 °C for 10 h, and cool to room temperature. It was washed with 15 mL of deionized water, dried under vacuum at 60 °C for 24 h, and annealed in an Ar atmosphere at 125 °C for 1 h to obtain 3% Pt/PyDTDO-3.

Example 2

Similar to Example 1, except that 2 mL of chloroplatinic acid was measured, and the obtained sample was named 5% Pt/PyDTDO-3.

Example 3

Similar to Example 1, except that 2.8 mL of chloroplatinic acid was measured, and the obtained sample was named 7% Pt/PyDTDO-3.

Example 4

Similar to Example 1, except that 3.6 mL of chloroplatinic acid was measured, and the obtained sample was named 9% Pt/PyDTDO-3.

Comparative Example 1

Weigh 5 mmol of dithiophene[3,2-B:2',3'-D]thiophene and 15 mmol of m-chloroperoxybenzoic acid into a round-bottomed flask according to the molar ratio, add 30 mL of anhydrous dichloromethane, 20 ℃ heated for 24 h, cooled to room temperature. Column chromatography was performed with petroleum ether:dichloromethane in a volume ratio of 2:1, and DTDO was obtained by vacuum drying at 50 °C for 24 h.

Weigh 0.5 mmol of DTDO, 0.25 mmol of 1,3,6,8-tetrabromopyrene, 1.5 mmol of anhydrous potassium carbonate, 0.015 mmol of tris(dibenzylideneacetone)dipalladium, 0.3 mmol of Pivalic acid, 0.03 mmol of tris(o-methoxyphenyl)phosphorus, and 10 mL of anhydrous phthalate. Heated at 120 °C for 72 h and cooled to room temperature. It was washed with 15 mL of deionized water and dried under vacuum at 60 °C for 24 h to obtain PyDTDO-3.

Comparative Example 2

Weigh 5 mmol of dithiophene[3,2-B:2',3'-D]thiophene and 15 mmol of m-chloroperoxybenzoic acid into a round-bottomed flask according to the molar ratio, add 30 mL of anhydrous dichloromethane, 20 ℃ heated for 24 h, cooled to room temperature. Column chromatography was performed with petroleum ether:dichloromethane in a volume ratio of 2:1, and DTDO was obtained by vacuum drying at 50 °C for 24 h.

Weigh 0.5 mmol of DTDO, 0.25 mmol of 1,3,6,8-tetrabromopyrene, 1.5 mmol of anhydrous potassium carbonate, 0.015 mmol of tris(dibenzylideneacetone)dipalladium, 0.3 mmol of Pivalic acid, 0.03 mmol of tris(o-methoxyphenyl)phosphorus, and 10 mL of anhydrous phthalate. Heated at 120 °C for 72 h and cooled to room temperature. It was washed with 15 mL of deionized water and dried under vacuum at 60 °C for 24 h to obtain PyDTDO-3.

Weigh 40 mg of PyDTDO-3, add 20 mL of deionized water and 2.8 mL of chloroplatinic acid, heat at 70 °C for 10 h, and cool to room temperature. Washed with 15 mL of deionized water, dried under vacuum at 60 °C for 24 h, and annealed in Ar atmosphere at 125 °C for 1 h to obtain 7% Pt/PyDTDO-3 without DMF (denoted as 7% Pt/PyDTDO-3-DF) .

Material Characterization

one. XRD spectrum results:

Figure 1 shows the XRD patterns of the samples of each component. It can be observed that all samples except 9% Pt/PyDTDO-3 have relatively obvious diffraction peaks at about 26°, which represent the π-π between conjugated polymers. of stacking. However, the diffraction peak of 9% Pt/PyDTDO at about 26° was significantly reduced or disappeared compared with other samples, which was caused by the addition of excess chloroplatinic acid, which hindered the π-π conjugation in the structure. In addition, no crystal-like diffraction peaks were observed in all samples, indicating that the synthesized conjugated polymers were in amorphous phase.

two. SEM, TEM pictures:

Figure 2 shows the prepared PyDTDO-3 (Figure 2(a)), 7% Pt/PyDTDO-3 (Figure 2(b)), and 7% Pt/PyDTDO-3-DF (Figure 2(c)) photocatalytic materials SEM. As shown in the figure, pure PyDTDO-3 showed a mixed growth morphology of rod-like and spherical. Compared with other SEM images, it was found that the loading of Pt had no effect on the morphology of PyDTDO-3. In addition, according to the TEM images of PyDTDO-3 (Fig. 2(d)-Fig. 2(f)) and 7% Pt/PyDTDO-3 (Fig. 2(g)-(i)), a mixture of rods and spheres can be observed growing image. The HRTEM image of 7% Pt/PyDTDO-3 (Fig. 2(i)) can clearly see the Pt loading.

three. FTIR spectrum results:

Figure 3 is the FTIR spectrum of each component sample, which is used to determine the material composition and surface functional groups of the photocatalyst. As shown in the figure, there are mainly four types of peaks, namely 2917 cm ^-1 , 1655 cm ^-1 , 1473 cm ^-1 , 1312 cm ^-1 and 1136 cm ^-1 . Among them, 2917 cm ^-1 is the stretching vibration peak of CH bond, 1655 cm ^-1 is the stretching vibration peak of aromatic ring (C=C), 1473 cm ^-1 belongs to the stretching vibration of thiophene (CSC), 1312 cm ^-1 and 1136 cm ^{- 1} is assigned to the stretching vibration of the sulfone group (O=S=O). In addition, it was observed that the sample of 9% Pt/PyDTDO-3 appeared a peak at 1022 cm ^-1 , which belonged to Pt-OH, and this result also corresponds to the result in XRD. In addition, it can be observed from the figure that different ratios of Pt/PyDTDO-3 and the carrier PyDTDO-3 show similar stretching and bending vibrations, indicating that the loading of Pt hardly affects the architecture of PyDTDO-3.

Four. XPS spectrum results:

Figure 4 shows the XPS spectrum, which can be used to characterize the material composition and valence state of the photocatalytic material. The XPS spectra of PyDTDO-3, 7%Pt/PyDTDO-3, and 7%Pt/PyDTDO-3-DF were analyzed to confirm the chemical states of the elements. It can be seen from Figure 4 that C, O, S and Br elements exist in all samples. The existence of Br element indicates that the polymerization reaction is not complete and there are Br end groups. The presence of Pt element can be seen from the full spectrum of 7% Pt/PyDTDO-3 and 7% Pt/PyDTDO-3-DF, which further indicates the successful loading of Pt.

Figure 5 shows the high-resolution spectra of PyDTDO-3, 7% Pt/PyDTDO-3 and 7% Pt/PyDTDO-3-DF. (a) The figure shows the O 1s XPS spectrum, and the peak at 532.1 eV represents the presence of the O=S bond. (b) The figure shows the C 1s XPS spectrum, the peak at 284.9 eV represents the existence of C=C, indicating the existence of aromatic ring skeleton in CPs. (c) The figure shows the S 2p spectrum, which can be divided into three groups of peaks. The peak around 169 eV corresponds to the S=O bond, the peak at 168 eV corresponds to the CSC in thiophene, and the peaks at 165 and 164 eV are S 2p (3d ^3/2 ) and S 2p (3d ^5/2 ), respectively, which belong to SS cross link. (d) The figure shows the XPS spectra of 7% Pt/PyDTDO-3 and 7% Pt/PyDTDO-3-DF Pt 4f. In 7% Pt/PyDTDO-3, two peaks appeared at binding energies of 74.9 and 71.6 eV, indicating the formation of Pt-O coordination bonds. In 7% Pt/PyDTDO-3-DF, in addition to the Pt-O coordination bonds of 78.4 and 72.7 eV, there are also Pt-Pt bonds of 75.6 and 70.8 eV, which are related to the Pt ⁴⁺ precursor during the reaction. Reduction produces Pt ⁰ corresponding. These results all correspond to the results in FTIR.

five. DRS spectrum results:

Figure 6 is the UV-Vis DRS spectrum, all CPs in the figure show a broad UV-Vis absorption range from 250 to 800 nm, which is due to the high degree of conjugation of the carrier PyDTDO-3, resulting in numerous formations between its Py and DTDO units. The electron delocalized orbitals overlap. In a series of Pt-loaded samples, the absorption intensity in the visible region increases with increasing Pt content, indicating that they have better light absorption properties. PyDTDO-3 with 9% loading may have a lower absorption strength than PyDTDO-3 with 7% loading due to its decreased atomic utilization. In addition, it is found that the visible light absorption intensity can be enhanced by the loading of Pt, which is beneficial to improve the visible light photolysis water splitting activity for hydrogen production. At the same time, the high content of DTDO in PyDTDO-3 is also the reason for its narrow band gap.

Performance Testing

20 mg of Pt/PyDTDO-3 prepared in the above different examples was added to the reaction flask, then 90 mL of deionized water, 10 mL of DMF and 17 g of ascorbic acid (sacrificial reagent) were added, and Ar gas was passed into the reaction flask for 30 min. After magnetic stirring for about 30 min, the Ar gas was turned off to make the reaction flask airtight. The gas in the reaction flask was pumped out and injected into the gas chromatograph for detection every 60 min.

Figure 7 is a graph of the hydrogen production performance of each component by photolysis of water. Figure 7(a) shows that with the prolongation of the illumination time, the hydrogen production of the material is also gradually increasing, showing a linear growth trend. Figure 7(b) shows that PyDTDO-3, 3% Pt/PyDTDO-3, 5% Pt/PyDTDO-3, 7% Pt/PyDTDO-3, 7% Pt/PyDTDO-3-DF and 9% Pt/ The H ₂ generation rates of PyDTDO-3 were 1.72, 2.16, 2.44, 3.91, 2.42 and 3.45 mmol·g ^-1 ·h ^-1 , respectively. Combining the figures, it can be found that when the loading of Pt reaches 7%, the photocatalytic activity of the material is the highest, which is 2.3 and 1.6 times that of PyDTDO-3 and 7% Pt/PyDTDO-3-DF, respectively. However, when the loading of Pt is insufficient or more than 7%, the activity growth is obviously slow, which may be due to the reduced utilization of Pt atoms. In addition, under the optimal loading conditions, the absence of DMF during the synthesis has a great influence on the hydrogen production, indicating the important role of DMF in the loading process of Pt atoms. Figure 7(c) shows the hydrogen production cycle diagram of 7% Pt/PyDTDO-3. It can be observed that the hydrogen production performance of 7% Pt/PyDTDO-3 does not decrease significantly after 30h (5 times) of cycling experiments. , remains stable. And it can also be observed from Figure 7(d) and Figure 8 that the XRD and FTIR patterns of 7% Pt/PyDTDO-3 before and after the photocatalytic reaction are almost unchanged, which further proves that 7% Pt/PyDTDO-3 has a certain stability. .

The above are only preferred specific embodiments of the present invention, and the protection scope of the present invention is not limited thereto. Any person skilled in the art can obviously obtain the simplicity of the technical solution within the technical scope disclosed in the present invention. Variations or equivalent substitutions fall within the protection scope of the present invention.

Claims (8)

1. A preparation method of conjugated polymer loaded metal platinum nanoparticles is characterized by comprising the following steps:

adding dithiophene [3,2-B:2 ', 3' -D ] thiophene and m-chloroperoxybenzoic acid serving as raw materials into a round-bottom flask, adding anhydrous dichloromethane, heating, cooling, carrying out column chromatography, and carrying out vacuum drying to obtain DTDO;

in N₂Under the condition, adding the DTDO, the 1,3,6, 8-tetrabromopyrene, the anhydrous potassium carbonate, the tris (dibenzylideneacetone) dipalladium, the pivalic acid, the tris (o-methoxyphenyl) phosphorus and the anhydrous o-dimethyl ether obtained in the step (1), heating, cooling, washing and drying to obtain PyDTDO-3;

adding deionized water and chloroplatinic acid into the PyDTDO-3,N,Nand (2) heating, cooling, washing, drying and annealing in an Ar atmosphere to obtain the Pt/PyDTDO-3 material for photocatalytic hydrogen evolution of the conjugated polymer loaded Pt.

2. The method for preparing the conjugated polymer supported metal platinum nanoparticles as claimed in claim 1, wherein in the step (1), the molar ratio of the bithiophene [3,2-B:2 ', 3' -D ] thiophene to the m-chloroperoxybenzoic acid is (1-10): (10-20); adding 20-50 mL of anhydrous dichloromethane into 1 mmol of total raw materials, wherein the total raw materials comprise dithiophene [3,2-B:2 ', 3' -D ] thiophene and m-chloroperoxybenzoic acid.

3. The method for preparing the conjugated polymer supported metal platinum nanoparticles as claimed in claim 1, wherein in the step (1), the heating temperature is 10-40 ℃ and the heating time is 20-30 h; the column chromatography is carried out according to the volume ratio (1-5): petroleum ether of (1-5): dichloromethane is eluent; the temperature of the vacuum drying is 20-80 ℃, and the drying time is 20-30 h.

4. The method for preparing the conjugated polymer supported metal platinum nanoparticle as claimed in claim 1, wherein the molar ratio of DTDO, 1,3,6, 8-tetrabromopyrene, anhydrous potassium carbonate, tris (dibenzylideneacetone) dipalladium, pivalic acid and tris (o-methoxyphenyl) phosphorus in step (2) is as follows: (0.1-0.8): (0.1-0.5): (1-3): (0.01-0.03): (0.1-0.5): (0.01-0.05), adding 5-15 mL of anhydrous o-dimethyl ether into 1 mmol of total raw materials, wherein the total raw materials comprise dithiophene [3,2-B:2 ', 3' -D ] thiophene and m-chloroperoxybenzoic acid.

5. The method for preparing the conjugated polymer supported metal platinum nanoparticles as claimed in claim 1, wherein the heating temperature in the step (2) is 80-150 ℃, and the heating time is 60-80 h; washing with 10-30 mL of deionized water; the temperature of the vacuum drying is 20-80 ℃, and the drying time is 20-30 h.

6. The method according to claim 1, wherein in step (3), the amount of PyDTDO-3 added is 20-60 mg, the amount of deionized water added is 5-20 mL, the amount of chloroplatinic acid added is 1-5 mL, and the amount of DMF added is 5-20 mL; the heating temperature is 50-100 ℃, and the heating time is 5-15 h; 10-30 mL of deionized water is used for washing; the temperature of the vacuum drying is 20-80 ℃, and the drying time is 20-30 h; the annealing temperature in the Ar gas atmosphere is 80-150 ℃, and the annealing time is 0.5-2 h.

7. The conjugated polymer supported Pt photocatalytic hydrogen evolution material Pt/PyDTDO-3 prepared based on any one of the methods of claims 1-6.

8. Use of the conjugated polymer supported Pt photocatalytic hydrogen evolution material Pt/PyDTDO-3 according to claim 1 or claim 7 for the preparation of a hydrogen evolution photocatalyst.

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