Preparation method and application of PtCu-TCP composite photocatalyst

Abstract

The present invention discloses a preparation method and application of a PtCu-TCP composite photocatalyst, which belongs to the field of photocatalysts. Hexahydrated chloroplatinic acid, trihydrated copper nitrate and a tris-olefin porous polymer (TCP) ethylene glycol dispersion are added to a two-necked flask and heated to 170-180°C for 4 hours. After the reaction is completed, the black precipitate is collected by centrifugation, washed and dried to obtain a PtCu-TCP composite photocatalyst. The preparation process of the composite photocatalyst is simple and the conditions are easy to control. According to structural characterization and performance characterization experiments, it can be found that the prepared PtCu-TCP composite photocatalyst has the advantages of stable chemical properties and high catalytic efficiency, and has high catalytic activity and stability in seawater; and because it has the advantages of easy availability of raw materials and low preparation cost, it has certain research and application value.

Description

Technical Field

[0001] The invention belongs to the technical field of nano material preparation and application, and particularly relates to a preparation method and application of a PtCu-TCP composite photocatalyst. Background Art

[0002] In recent years, problems such as global energy shortage and environmental degradation have become increasingly prominent and have become obstacles to social and environmental sustainability. Solar-driven photocatalytic sustainable conversion of H2O into environmentally friendly and clean hydrogen fuel has attracted great attention and is considered to be one of the most promising and attractive ways to meet future energy needs and solve serious environmental problems. In order to achieve efficient hydrogen evolution, surface regulation has been attempted to increase adsorption capacity and catalytic activity by changing surface properties or controlling specific semiconductor coupling, which can directly increase the number and distribution of active sites. Seawater is abundant on Earth, but due to the large amount of Na in seawater, the surface of the hydrogen evolution reaction is not suitable for the production of hydrogen. + , K + 、Cl - The presence of plasma leads to a decrease in the performance of photocatalysts, thus limiting the application of photocatalysts in seawater systems.

[0003] TCP is a new type of visible-light-driven semiconductor with very attractive optical properties and excellent chemical stability, and is regarded as a candidate for photocatalytic applications. Triptycene with an extended π plane is composed of three benzene units and exhibits excellent electron transport ability. POPs, which have similar characteristics to metal-organic frameworks (MOFs), have been applied in photocatalysis due to their large surface area, good chemical stability and excellent physicochemical properties. However, the photocatalytic hydrogen evolution efficiency of TCP remains low. Therefore, improving the photocatalytic activity by precisely modifying the nanostructure of TCP remains a challenging task.

[0004] Noble metal nanoparticles (NPs), such as Pt, Au, Ag, or Pd, have attracted considerable attention as co-catalysts for the hydrogen evolution reaction (HER). However, metals like Co, Cu, and Ni are more readily available at a lower cost. Despite their relatively poor activity, their combination with noble metals in bimetallic systems can exhibit much higher activity compared to the single metal components. In this regard, PtCu NPs have attracted considerable interest as they can provide significant activity enhancement compared to single Pt catalysts for applications such as methanol oxidation, hydrogen production, CO2 reduction, NO reduction, or electrocatalysis.

[0005] There is no research on composite photocatalysts in which Pt and Cu are coated on triptycene-based polymers to form PtCu nanoparticles and triptycene polymers. Summary of the Invention

[0006] Based on the above problems, the present invention aims to provide a method for preparing a PtCu-TCP composite photocatalyst and its application in seawater hydrogen production. PtCu nanoparticles are loaded on a tridiscene porous polymer (TCP) to form a composite photocatalyst.

[0007] The technical solution adopted in the present invention is:

[0008] A method for preparing a PtCu-TCP composite photocatalyst comprises the following steps:

[0009] Triskelion porous polymer (TCP) was dispersed in ethylene glycol to obtain a TCP glycol dispersion; chloroplatinic acid hexahydrate, copper nitrate trihydrate and the TCP glycol dispersion were added to a two-necked flask and heated to 170°C to 180°C for 4 hours. After the reaction was completed, the black precipitate was collected by centrifugation, washed, and vacuum-dried at 60°C for 12 hours to obtain a PtCu-TCP composite photocatalyst.

[0010] The mass ratio of the total mass of chloroplatinic acid hexahydrate and copper nitrate trihydrate to TCP is 0.1 to 1:1. The molar ratio of chloroplatinic acid hexahydrate to copper nitrate trihydrate is 5 to 9:1. Preferably, the molar ratio of chloroplatinic acid hexahydrate to copper nitrate trihydrate is 7:1.

[0011] The triptycene porous polymer of the present invention is prepared by the following method, the specific steps are as follows:

[0012] (1) Preparation of trinitrotriptycene: Weigh triptycene and dissolve it in nitric acid to obtain a 25 g / L nitric acid solution of triptycene; stir and heat at 75°C for 24 h, cool, wash with deionized water, dry at 60°C, and separate and purify by column chromatography using petroleum ether:ethyl acetate.

[0013] (2) Preparation of triaminotriptycene: The above-mentioned trinitrotriptycene was added to a round-bottom flask and Raney nickel was added. After vacuuming, tetrahydrofuran and hydrazine hydrate were injected and heated at 60°C for 6 hours. Then, dichloromethane and tetrahydrofuran were used as detergents, and the sample was washed several times on diatomaceous earth and then dried in a spin-drying machine. The amount ratio of trinitrotriptycene, Raney nickel, tetrahydrofuran and hydrazine hydrate was 1g:1g:20mL:1.5mL.

[0014] (3) Preparation of tribromotriptycene: The above-mentioned triaminotriptycene was added to a round-bottom flask and deionized water and hydrobromic acid were added, and the mixture was rapidly cooled with ice. Then, an aqueous sodium nitrite solution was added and the mixture was left for 20 minutes. Then, a solution of cuprous bromide in hydrobromic acid was added and the mixture was heated at 120°C for 2 hours. The mixture was separated and dried by spin drying. The mixture was separated and purified by column chromatography using petroleum ether. The ratio of triaminotriptycene, deionized water and hydrobromic acid was 1 g: 10 ml: 3 mL.

[0015] (4) Preparation of triptycene porous polymer: The above-mentioned tribromotriptycene, 1,4-phenylenediboronic acid, palladium acetate and triphenylphosphine were added to a sealed reaction tube, and after vacuuming, tetrahydrofuran and potassium carbonate aqueous solution were injected. The mixed solution was reacted at 65°C for 12 hours. After the reaction was completed, the mixture was repeatedly washed with tetrahydrofuran, anhydrous ethanol and deionized water, filtered and dried at 60°C to obtain TCP.

[0016] Furthermore, in the step (1), the volume ratio of petroleum ether to ethyl acetate is 10:1.

[0017] Furthermore, in step (3), the volume of the sodium nitrite aqueous solution added is 0.5 times the volume of the deionized water; and the volume of the cuprous bromide hydrobromic acid solution added is 0.5 times the volume of the deionized water. The concentration of the sodium nitrite aqueous solution is 160 g / L; and the cuprous bromide hydrobromic acid solution is prepared by dispersing cuprous bromide in the hydrobromic acid solution, and its concentration is 440 g / L.

[0018] Furthermore, in the step (4), the molar ratio of tribromotriptycene, 1,4-phenylenediboronic acid, palladium acetate and triphenylphosphine is 1:1.6-1.7:0.03-0.04:0.07-0.08.

[0019] Furthermore, in the step (4), the ratio of tribromotriptycene, tetrahydrofuran and potassium carbonate aqueous solution is 100g:2L:5L; and the molar concentration of the potassium carbonate aqueous solution is 0.3-0.4mol / L.

[0020] The present invention also provides the use of the above-mentioned PtCu-TCP composite photocatalyst in photocatalytic hydrogen production. In a pure water or seawater hydrogen production system containing a sacrificial agent, the PtCu-TCP composite photocatalyst has good stability and produces hydrogen faster in seawater than in pure water.

[0021] Compared with the prior art, the present invention has the following beneficial effects: the composite photocatalyst prepared by this method has good stability and no secondary pollution. The photocatalytic hydrogen production rate of the Pt7Cu1-TCP composite catalyst in deionized water can reach 3010.67 μmol g within 180 min. -1 h -1 The yield in seawater can reach 3255 μmol g -1 h -1 In addition, the preparation method of the composite photocatalyst has the advantages of being simple, easy to control the preparation conditions, and no secondary pollution, and has certain research and application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be further described below with reference to the accompanying drawings.

[0023] Figure 11 is the X-ray diffraction pattern of pure TCP and PtCu-TCP composite catalyst prepared in Examples 1-3 of the present invention;

[0024] Figure 2 1 is an infrared spectrum of pure TCP and PtCu-TCP composite catalysts prepared in Examples 1-3 of the present invention;

[0025] Figure 3 1 is a transmission electron micrograph of pure TCP (a) and PtCu-TCP composite catalyst (b) prepared in Example 1 of the present invention;

[0026] Figure 4 Graph showing the photocatalytic hydrogen production rates of pure TCP and PtCu-TCP composite catalysts prepared in Examples 1-3 of the present invention.

[0027] Figure 5 This is a hydrogen production cycle diagram of the PtCu-TCP composite catalyst prepared in Example 1 of the present invention; DETAILED DESCRIPTION

[0028] The present invention will now be further described with reference to specific examples. The following examples are intended to illustrate the present invention rather than to further limit the present invention.

[0029] Example 1

[0030] (1) Preparation of triptycene porous polymer:

[0031] Preparation of trinitrotriptycene: Weigh 2.5 g of triptycene and dissolve it in 100 mL of nitric acid. Stir and heat in a 75°C oil bath for 24 h. After cooling, wash with 4 L of deionized water, dry at 60°C, and separate and purify it by column chromatography with a volume ratio of petroleum ether:ethyl acetate (10:1).

[0032] Preparation of triaminotriptycene: 1 g of the above-mentioned trinitrotriptycene was added to a round-bottom flask and 1 g of Raney nickel was added. After vacuuming, 20 mL of tetrahydrofuran and 1.5 mL of hydrazine hydrate were injected and heated at 60 ° C for 6 h to obtain. Dichloromethane and tetrahydrofuran were used as detergents, and the sample was washed several times on diatomaceous earth and then spin-dried.

[0033] Preparation of tribromotriptycene: 1 g of the above-mentioned triaminotriptycene was added to a round-bottom flask and 10 mL of deionized water and 3 mL of hydrobromic acid were added, and the mixture was rapidly cooled with ice. Then, 0.8 g of sodium nitrite aqueous solution (5 mL) was added and the mixture was allowed to stand for 20 min before adding a solution of 2.2 g of cuprous bromide in hydrobromic acid (5 mL). The mixture was heated at 120 ° C for 2 h and then separated. The mixture was spin-dried and purified by column chromatography using petroleum ether.

[0034] Preparation of triptycene porous polymer: 0.1 g of tribromotriptycene, 0.054 g of 1,4-phenylenediboronic acid, 0.0015 g of palladium acetate and 0.00395 g of triphenylphosphine were added to a sealed reaction tube. After vacuuming, 20 mL of tetrahydrofuran and potassium carbonate aqueous solution (0.2192 g of potassium carbonate dissolved in 5 mL of deionized water) were injected. The mixed solution was reacted at 65°C for 12 h. After the reaction, the mixture was repeatedly washed with tetrahydrofuran, anhydrous ethanol and deionized water, filtered, and dried at 60°C to obtain TCP.

[0035] (2) Preparation of PtCu-TCP composite photocatalyst: 0.1 g of the prepared TCP was dispersed in 20 mL of ethylene glycol, and then 0.078 g of chloroplatinic acid hexahydrate, 0.00519 g of copper nitrate trihydrate and TCP ethylene glycol dispersion were added to a two-necked flask and slowly heated to 180 °C and maintained for 4 h. After the reaction was completed, the temperature was naturally lowered, and the black precipitate was washed and collected to obtain a Pt7Cu1-TCP composite photocatalyst.

[0036] Example 2

[0037] (1) Preparation of TCP: Same as Example 1:

[0038] (2) Preparation of PtCu-TCP composite photocatalyst: 0.1 g of the prepared TCP was dispersed in 20 mL of ethylene glycol, and then 0.0621 g of chloroplatinic acid hexahydrate, 0.00579 g of copper nitrate trihydrate and TCP ethylene glycol solution dispersion were added to a two-necked flask and slowly heated to 180 °C and maintained for 4 h. After the reaction was completed, the temperature was naturally lowered, and the black precipitate was washed and collected to obtain a Pt5Cu1-TCP composite photocatalyst.

[0039] Example 3

[0040] (1) Preparation of TCP: Same as Example 1:

[0041] (2) Preparation of PtCu-TCP composite photocatalyst: 0.1 g of the prepared TCP was dispersed in 20 mL of ethylene glycol, and then 0.097 g of chloroplatinic acid hexahydrate, 0.005025 g of copper nitrate trihydrate and TCP ethylene glycol solution dispersion were added to a two-necked flask and slowly heated to 180 °C and maintained for 4 h. After the reaction was completed, the temperature was naturally lowered, and the black precipitate was washed and collected to obtain a Pt9Cu1-TCP composite photocatalyst.

[0042] Comparative Example 1

[0043] Preparation of Pt-TCP

[0044] (1) Preparation of TCP: Same as Example 1:

[0045] (2) Preparation of Pt-TCP composite photocatalyst: 0.1 g of the prepared TCP was dispersed in 20 mL of ethylene glycol, and then 0.01553 g of chloroplatinic acid hexahydrate and TCP ethylene glycol solution dispersion were added to a two-necked flask and slowly heated to 180 °C and maintained for 4 h. After the reaction was completed, the temperature was naturally lowered, and the black precipitate was washed and collected to obtain a Pt-TCP composite photocatalyst.

[0046] Comparative Example 2

[0047] Preparation of Cu-TCP

[0048] (1) Preparation of TCP: Same as Example 1:

[0049] (2) Preparation of Cu-TCP composite photocatalyst: 0.1 g of the prepared TCP was dispersed in 20 mL of ethylene glycol, and then 0.007248 g of copper nitrate trihydrate and TCP ethylene glycol solution dispersion were added to a two-necked flask and slowly heated to 180 °C and maintained for 4 h. After the reaction was completed, the temperature was naturally lowered, and the black precipitate was washed and collected to obtain a Pt-TCP composite photocatalyst.

[0050] 1. Composition determination and morphology of PtCu-TCP composite photocatalyst.

[0051] The crystal structures of pure TCP, Pt5Cu1, Pt7Cu1 and Pt9Cu1 composite photocatalysts prepared in Examples 1-3 were analyzed by X-ray diffractometer of Japan D / MAX2500, wherein the X-ray was Cu target Kα The voltage was 40 kV, the current was 100 mA, the step size was 0.02°, and the scanning range was 5° to 80°. Figure 1 As shown in Figure 3, the PtCu-TCP composites with different PtCu ratios exhibit the same peak positions, which are 39.9°, 46.4° and 67.7° corresponding to the crystal planes (100), (200) and (220), respectively. However, no TCP peak appears in the X-ray diffraction pattern of the PtCu-TCP composite material, which is due to the amorphous state and non-crystalline structure of TCP.

[0052] All catalysts were observed using a Thermo Fisher IS50 infrared spectrometer at 1466 cm -1 and 817cm -1 The characteristic peak at 2856-3090cm is due to the carbon-carbon double bond skeleton vibration of the benzene ring in the triptycene unit. -1 The characteristic peaks at are attributed to the CH bonds of TCP. Furthermore, as the concentration of TCP increases, the corresponding peak heights also increase, which confirms the successful preparation of the PtCu-TCP composite sample.

[0053] 2. TEM images of pure TCP and PtCu-TCP composite photocatalysts

[0054] The morphology of pure TCP and PtCu-TCP composite photocatalysts prepared in Examples 1-3 was observed using a JEOL 2100 high-resolution transmission electron microscope. Figure 3 As shown in the figure, Figure 3 (a) is a pure sample of TCP consisting of a nanosphere. Figure 3 (b) is the PtCu-TCP composite photocatalyst. It can be seen that the morphology is that smaller PtCu nanoparticles are tightly attached to the TCP surface.

[0055] 3. Study on the photocatalytic performance and potential applications of pure TCP and PtCu-TCP composite photocatalysts

[0056] The photocatalytic hydrogen production performance of PtCu-TCP samples was studied under simulated solar irradiation using deionized water or seawater / acetonitrile / triethanolamine mixed solutions. Photocatalytic hydrogen production was measured on an 180 mL sealed reactor at atmospheric pressure and ambient temperature. 10 mg of the prepared catalyst was weighed and dispersed in a mixed solution of 36 mL acetonitrile, 4 mL triethanolamine, and 0.4 μL deionized water or seawater, and the mixture was then sonicated for 30 min. Before irradiation, high-purity Ar was passed into the reaction system for 25 min to drain the air. The reactor was irradiated with an AM1.5G solar simulator under a 300 W xenon lamp. Possible gaseous products, such as H2, were detected using a gas chromatograph equipped with an FID and TCD detector. In addition, a cycle experiment was carried out on the best catalyst under the same experimental conditions.

[0057] The composite photocatalyst prepared in Examples 1-3 has the following performance on photocatalytic hydrogen production: Figure 4 As shown. Figure 4 It can be seen that the hydrogen production rate of Pt7Cu1-TCP in seawater can reach 3255 μmol g within 180 min. -1 h -1 It can be seen that the prepared PtCu-TCP composite photocatalyst has high photocatalytic activity. Figure 5 It can be seen that the PtCu-TCP composite catalyst is still very stable in seawater or deionized water after four cycles of illumination.

Claims

1. A method for preparing a PtCu-TCP composite photocatalyst, characterized in that: The following steps are involved: Tripterygium porous polymer (TCP) is dispersed in ethylene glycol to obtain TCP ethylene glycol dispersion; chloroplatinic acid hexahydrate, copper nitrate trihydrate and TCP ethylene glycol dispersion are added to a two-necked flask and heated to 170°C~180°C and maintained for 4 hours. After the reaction is completed, the precipitate is collected by centrifugation, washed and dried to obtain a PtCu-TCP composite photocatalyst.

2. The method for preparing the PtCu-TCP composite photocatalyst according to claim 1, wherein: The molar ratio of chloroplatinic acid hexahydrate: copper nitrate trihydrate is 5~9:

1.

3. The method for preparing the PtCu-TCP composite photocatalyst according to claim 1, wherein: The mass ratio of the total mass of chloroplatinic acid hexahydrate and copper nitrate trihydrate to TCP is 0.1~1:

1.

4. The method for preparing the PtCu-TCP composite photocatalyst according to claim 1, wherein: The preparation method of the triptycene porous polymer is as follows: (1) Preparation of trinitrotriptycene: Dissolve triptycene in nitric acid to obtain a nitric acid solution of triptycene, stir and heat in an oil bath at 75°C for 24 hours, cool, wash, dry, and purify by column chromatography using petroleum ether:ethyl acetate in a volume ratio of 10:1; wherein the concentration of the nitric acid solution of triptycene is 25 g / L; (2) Preparation of triaminotriptycene: trinitrotriptycene and Raney nickel obtained in step (1) were added to a round-bottom flask, and tetrahydrofuran and hydrazine hydrate were injected after vacuuming. The flask was heated at 60°C for 6 h. The product was washed with dichloromethane and tetrahydrofuran and then dried by rotary evacuation. The ratio of trinitrotriptycene, Raney nickel, tetrahydrofuran and hydrazine hydrate was 1 g:1 g:20 mL:1.5 mL. (3) Preparation of tribromotriptycene: add the triaminotriptycene obtained in step (2) into a round-bottom flask, add deionized water and hydrobromic acid, rapidly cool, then add sodium nitrite aqueous solution and react for 20 minutes, then add cuprous bromide hydrobromic acid solution, heat at 120°C for 2 hours, separate the liquids, spin dry, and separate and purify with petroleum ether by column chromatography; wherein the amount ratio of triaminotriptycene, deionized water and hydrobromic acid is 1g:10ml:3mL; (4) Preparation of triptycene porous polymer: tribromotriptycene, 1,4-phenylenediboronic acid, palladium acetate and triphenylphosphine obtained in step (3) were added to a sealed reaction tube, and after evacuation, tetrahydrofuran and potassium carbonate aqueous solution were injected to obtain a mixed solution; the mixed solution was reacted at 65°C for 12h. After the reaction was completed, the mixture was washed and dried to obtain TCP; wherein the molar ratio of tribromotriptycene, 1,4-phenylenediboronic acid, palladium acetate and triphenylphosphine was 1:1.6~1.7:0.03~0.04:0.07~0.

08.

5. The method for preparing the PtCu-TCP composite photocatalyst according to claim 4, wherein: In step (3), the volume of the sodium nitrite aqueous solution added is 0.5 times the volume of deionized water; the volume of the cuprous bromide hydrobromic acid solution added is 0.5 times the volume of deionized water.

6. The method for preparing the PtCu-TCP composite photocatalyst according to claim 5, wherein: The concentration of the sodium nitrite aqueous solution is 160 g / L.

7. The method for preparing the PtCu-TCP composite photocatalyst according to claim 6, wherein: The hydrobromic acid solution of cuprous bromide is prepared by dispersing cuprous bromide in a hydrobromic acid solution, and the concentration thereof is 440 g / L.

8. The method for preparing the PtCu-TCP composite photocatalyst according to claim 4, wherein: In step (4), the ratio of tribromotriptycene, tetrahydrofuran and potassium carbonate aqueous solution is 100 g:2 L:5 L; the molar concentration of the potassium carbonate aqueous solution is 0.3-0.4 mol / L.

9. An application of a PtCu-TCP composite photocatalyst prepared by the method according to any one of claims 1 to 8, characterized in that: Application of the PtCu-TCP composite photocatalyst in photocatalytic hydrogen evolution.

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