Preparation method and application of copper-doped nanoribbon crystalline red phosphorus photocatalyst

Abstract

The invention discloses a method for preparing a copper-doped nano-ribbon crystalline red phosphorus photocatalyst, and belongs to the technical field of phosphorus chemical materials. The method comprises the following steps: adding a nano-ribbon crystalline red phosphorus dispersion and a copper-rich metal salt into a beaker, and then, after ultrasonic stirring, photodepositing the dispersion at 0°C to 10°C and under illumination conditions, and then filtering the dispersion after photodeposition, and vacuum drying the filter residue to obtain copper-doped nano-ribbon crystalline red phosphorus. The copper-doped nano-ribbon crystalline red phosphorus is applied to a photocatalytic hydrogen evolution reaction. The catalyst of the invention efficiently evolves hydrogen without a sacrificial agent, and the method of the invention is simple and highly repeatable, and is suitable for industrial applications and market promotion applications.

Description

Technical Field

[0001] The invention relates to a preparation method and application of a copper-doped nano-belt-shaped crystal red phosphorus photocatalyst, belonging to the technical field of phosphorus chemical materials. Background Art

[0002] Nano-ribbon crystalline red phosphorus not only has a suitable energy band structure and a wider light absorption range, but also performs well enough as a single-substance photocatalyst to meet the requirements of photocatalytic hydrogen production. Nano-ribbon crystalline red phosphorus can be easily doped with various metal salts to introduce metals to increase the yield of photocatalytic hydrogen production. However, most metal-doped red phosphorus are single-atom loaded, which makes it difficult to repeat the same experimental results. Therefore, developing a practical and direct method to prepare red phosphorus photocatalysts with high metal loading has great development prospects in this field. Summary of the invention

[0003] In view of the problems existing in the prior art, the present invention provides a method for preparing a copper-doped nano-belt crystalline red phosphorus photocatalyst. The present invention can not only improve the repeatability of the experiment, but also greatly increase the photocatalytic hydrogen production output.

[0004] The preparation method of the copper-doped nano-belt crystalline red phosphorus photocatalyst of the present invention comprises the following steps: adding a water dispersion of nano-belt crystalline red phosphorus and a copper-rich metal salt into a beaker, stirring the dispersion to fully dissolve the nano-belt crystalline red phosphorus, performing photodeposition on the dispersion under light conditions, and adding circulating water at 0°C to 10°C around the dispersion, and after the photodeposition, filtering the dispersion, and drying the filter residue in a vacuum drying oven to obtain the copper-doped nano-belt crystalline red phosphorus.

[0005] The nano-ribbon crystalline red phosphorus is prepared by placing bismuth powder, iodine and red phosphorus together in a quartz tube, performing a temperature rise and fall treatment on the quartz tube in a three-stage temperature zone tubular furnace under vacuum conditions to obtain block crystalline red phosphorus, grinding the quartz tube into powder and washing it with hydrochloric acid. After washing and drying, the powdered crystalline red phosphorus is placed in deionized water (120 mg to 170 mg of crystalline red phosphorus is added to every 170 mL of deionized water), and high-power ultrasonic dispersion (ultrasound at 0 to 15° C. and ultrasonic power of 900 W to 1200 W for 3 to 6 hours), and centrifuging and freeze-drying the crystalline red phosphorus dispersion to obtain the nano-ribbon crystalline red phosphorus. The mass ratio of red phosphorus to bismuth to iodine is 40:1:1 to 30:1:1. The temperature of the two sections on the source side of the three-stage temperature zone tubular furnace is set to 450° C. to 480° C., and the temperature of the one section on the growth side is set to 420° C. to 440° C. At 450℃, the catalyst and red phosphorus are placed in two sections on the source side of a three-section temperature zone tubular furnace, and the temperature is increased at a heating rate of 2.5℃ / min. After constant temperature reaction for 18h~24h, the temperature is lowered to room temperature at a rate of 0.7℃ / min~1℃ / min, and blocky crystalline red phosphorus grows in one section on the growth side.

[0006] The mass ratio of the nanoribbon crystalline red phosphorus to the copper-rich metal salt is 5:1-2; the copper-rich metal salt is CuCl 2 、Cu(NO 3 ) 2 、Cu(OAc) 2 .

[0007] The wavelength of light in the illumination is 300-1200nm.

[0008] The beneficial effects of the present invention are as follows:

[0009] Compared with the preparation method of single-atom supported crystalline red phosphorus, the catalyst prepared by the method of the present invention can not only efficiently precipitate hydrogen without a sacrificial agent, but also has a simple preparation method and high repeatability. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 XRD comparison diagram of the copper-doped nano-ribbon crystalline red phosphorus prepared in Example 1, the nano-ribbon crystalline red phosphorus and the crystalline red phosphorus;

[0011] Figure 2 The XPS spectrum of the copper-doped nanoribbon crystalline red phosphorus prepared in Example 1; Figure a is the overall spectrum of the material, and Figure b is the peak fitting analysis result of the P 2p peak;

[0012] Figure 3 This is a comparison chart of the photocatalytic hydrogen production effects of the copper-doped nanoribbon crystalline red phosphorus prepared in Example 1, the nanoribbon crystalline red phosphorus, and the crystalline red phosphorus. DETAILED DESCRIPTION

[0013] The present invention is further described in detail below by way of examples, but the protection scope of the present invention is not limited to the above contents; the methods in the examples are conventional methods unless otherwise specified, and the reagents are conventional commercially available reagents or reagents prepared according to conventional methods unless otherwise specified; Example 1

[0014] 1. 1500 mg of block crystalline red phosphorus FRP, 50 mg of bismuth, and 50 mg of iodine were vacuum-sealed in a quartz tube (inner diameter 1.5 cm, length 20 cm). The sealed quartz tube was placed in a tubular furnace with three temperature zones. The temperature of the two sections on the source side was set to 480°C, and the temperature of the one section on the growth side was set to 450°C. The heating rate was 2.5°C / min, and the reaction was carried out at a constant temperature for 20 hours. Finally, the reaction product was cooled to room temperature at a rate of 0.7°C / min, and the prepared crystalline red phosphorus was taken out by breaking the quartz tube. After grinding it into powder, it was washed with hydrochloric acid to remove a small amount of residual bismuth, and then washed clean and dried. 120 mg of crystalline red phosphorus powder was added to a beaker containing 170 mL of deionized water, and ultrasonicated in an ultrasonic disperser at an ultrasonic power of 1200 W for 3 h (ensuring that the temperature was 10° C. during ultrasonication), and finally centrifuged at 3000 rpm to precipitate the large particles of crystalline red phosphorus that were not peeled off by ultrasonication at the bottom of the centrifuge tube, and the supernatant was centrifuged at 13000 r / min to obtain a precipitate, and the precipitate was freeze-dried to obtain a nano-ribbon crystalline red phosphorus C-RP;

[0015] 2. Take 50 mL of 1 mg / mL nanoribbon crystalline red phosphorus dispersion and mix with CuCl 2 10 mg was added to a beaker and ultrasonically stirred to fully dissolve it. A 300W xenon lamp equipped with a cut 300nm filter was used to photodeposit the dispersion, and 5°C circulating water was added around it. After photodeposition, the dispersion was filtered to remove excess impurities, and the filter membrane was placed in a vacuum drying oven at 60°C to obtain copper-doped nanoribbon crystalline red phosphorus Cu / C-RP. Its XRD pattern is shown in Figure 1 From the figure, it can be seen that the nanoribbon crystalline red phosphorus (C-RP) has diffraction peaks corresponding to different crystal planes at 15.3° (001), 17.2° (200), 22.4° (201), 30.8° (002), 34.1° (400), 38.6° (402) and 40.1° (400). Compared with the bulk crystalline red phosphorus (FRP), C-RP shows more crystal plane diffraction peaks. Compared with Cu / C-RP, only the diffraction peaks of 34.1° (400), 38.6° (402) and 40.1° (400) of C-RP show normal intensity, and the intensity of other diffraction peaks is significantly reduced, which means that the optical deposition selectively deposits Cu on other crystal planes of C-RP.

[0016] Figure 2 a is the overall XPS spectrum, from which we can clearly identify the peaks of P 2p, P 2s, O 1s, C 1s, and Cu2p; Figure 2 In b, we performed a peak fitting analysis on the P 2p peak. Compared with Figure C-RP, the P2p of Cu / C-RP 1 / 2 、P 2p 1 / 2The three peaks of PO and Cu / C-RP all shifted to the direction of lower binding energy, indicating that the P atoms in the composite Cu / C-RP were in a slightly electron-rich state. This also shows that Cu / C-RP can more easily provide electrons to convert H into Cu during photocatalytic hydrogen evolution than C-RP. 2 O reduction to H 2 .

[0017] 3. Blocky crystalline red phosphorus FRP, nanobelt crystalline red phosphorus C-RP, and copper-doped nanobelt crystalline red phosphorus Cu / C-RP were used as catalysts in photocatalytic pure water hydrogen production. 20 mg of catalyst and 3% of the catalyst mass of chloroplatinic acid were added to 50 mL of water. The photocatalytic reaction was carried out in a heat-resistant glass reaction pool connected to a glass closed vacuum circulation system. A 300 W xenon lamp was used as the light source, and the filter was am1.5. Before the test, the entire photocatalytic reaction system was evacuated to a vacuum state and checked for airtightness. Finally, the generated gas was automatically collected and analyzed every half an hour by a connected gas chromatograph; the comparison of the photocatalytic hydrogen production performance of FRP, C-RP and Cu / C-RP is shown in Figure 3 Compared with FRP and C-RP, Cu / C-RP exhibited a stronger photocatalytic hydrogen evolution effect, and its hydrogen evolution amount was increased by 130 times and 32 times compared with FRP and C-RP, respectively. Example 2

[0018] 1. Vacuum seal 650 mg red phosphorus, 16.5 mg bismuth, and 16.5 mg iodine in a quartz tube (1.5 cm inner diameter, 10 cm length). Place the sealed quartz tube in a tube furnace with three temperature zones, with the temperature of the two sections on the source side set to 450°C and the temperature of the one section on the growth side set to 420°C. The heating rate is 2.5°C / min, and the reaction is kept at a constant temperature for 22 hours. Finally, the reaction product is cooled to room temperature at a rate of 1°C / min. Break the quartz tube to take out the prepared crystalline red phosphorus, grind it into powder, wash it with hydrochloric acid to remove a small amount of residual bismuth, then wash it clean and dry it. 170 mg of crystalline red phosphorus powder was added to a beaker containing 170 mL of deionized water, and ultrasonicated in an ultrasonic disperser. The ultrasonic power was 900 W, and the ultrasonication was continued for 6 seconds and stopped for 8 seconds, for a total of 5 hours (ensuring that the temperature during ultrasonication was 0°C). Finally, the mixture was centrifuged at 5000 rpm to precipitate the large particles of crystalline red phosphorus that were not peeled off by ultrasonication at the bottom of the centrifuge tube. The supernatant was centrifuged at 13000 r / min to obtain a precipitate, and the precipitate was freeze-dried to obtain a nano-ribbon crystalline red phosphorus.

[0019] 2. Take 100 mL of 1 mg / mL nanoribbon crystalline red phosphorus dispersion and mix with CuCl 240 mg was added to a beaker and ultrasonically stirred to fully dissolve it. A 300W xenon lamp equipped with a cut 420nm filter was used to photodeposit the dispersion, and 5°C circulating water was added around it. After photodeposition, the dispersion was filtered to remove excess impurities, and the filter membrane was placed in a vacuum drying oven at 60°C to obtain copper-doped nanoribbon crystalline red phosphorus;

[0020] 3. The copper-doped nanoribbon crystalline red phosphorus was used in the photocatalytic hydrogen production from pure water, and the photocatalytic hydrogen evolution yield was as high as 1836.21 μmol g -1 h -1 . Example 3

[0021] 1. Vacuum seal 1200 mg red phosphorus, 35 mg bismuth, and 35 mg iodine in a quartz tube (1.5 cm inner diameter, 15 cm length). Place the sealed quartz tube in a tube furnace with three temperature zones. Set the temperature of the two sections on the source side to 465°C, and the temperature of the one section on the growth side to 435°C. The heating rate is 2.5°C / min, and the reaction is kept at a constant temperature for 18 hours. Finally, the reaction product is cooled to room temperature at a rate of 1°C / min. Break the quartz tube to take out the prepared crystalline red phosphorus, grind it into powder, wash it with hydrochloric acid to remove a small amount of residual bismuth, then wash it clean and dry it. Take 150 mg of crystalline red phosphorus powder and add it to a beaker containing 170 mL of deionized water. Ultrasonicate it in an ultrasonic disperser with an ultrasonic power of 1000 W for 5 hours (ensure that the temperature is 15°C during ultrasound). Finally, centrifuge at 4000 rpm to precipitate the large particles of crystalline red phosphorus that have not been peeled off by ultrasound at the bottom of the centrifuge tube, take the supernatant and centrifuge at 13000 r / min to obtain a precipitate, and freeze-dry the precipitate to obtain nano-ribbon crystalline red phosphorus;

[0022] 2. Take 50 mL of 1 mg / mL nanoribbon crystalline red phosphorus dispersion and mix with Cu(NO 3 ) 2 15 mg was added to a beaker and ultrasonically stirred to fully dissolve it. A 300W xenon lamp equipped with a cut 400nm filter was used to photodeposit the dispersion, and 0°C circulating water was added around it. After photodeposition, the dispersion was filtered to remove excess impurities, and the filter membrane was placed in a vacuum drying oven at 60°C to obtain copper-doped nanoribbon crystalline red phosphorus;

[0023] 3. The copper-doped nanoribbon crystalline red phosphorus was used in the photocatalytic hydrogen production from pure water, and the photocatalytic hydrogen evolution yield was as high as 1902.31 μmol g -1 h -1 .

Claims

1. Application of a copper-doped nanoribbon crystalline red phosphorus photocatalyst in photocatalytic hydrogen evolution reaction, characterized in that: The copper-doped nano-ribbon crystalline red phosphorus photocatalyst is prepared by adding a nano-ribbon crystalline red phosphorus dispersion and a copper-rich metal salt into a beaker, and then, after ultrasonic stirring, photodepositing the dispersion at 0°C to 10°C under light conditions. After the photodeposition, the dispersion is filtered and the filter residue is vacuum dried to obtain the nano-ribbon crystalline red phosphorus. The nano-ribbon crystalline red phosphorus is prepared by putting bismuth powder, iodine and red phosphorus into a quartz tube together, and, under vacuum conditions, using a three-stage temperature zone tubular furnace to perform a temperature rise and fall treatment on the quartz tube to obtain a block crystalline red phosphorus. The block crystalline red phosphorus is ground into powder and then washed with hydrochloric acid. After washing and drying, the powdered crystalline red phosphorus is put into deionized water, and dispersed by high-power ultrasonication. The crystalline red phosphorus dispersion is centrifuged and freeze-dried to obtain the nano-ribbon crystalline red phosphorus. The temperatures of the two sections on the source side of the three-section temperature zone tubular furnace are set to 450°C ~ 480°C, and the temperature of the one section on the growth side is 420°C ~ 450°C. Bismuth powder, iodine and red phosphorus are placed in the two sections on the source side of the three-section temperature zone tubular furnace. The temperature is increased at a heating rate of 2.5°C / min. After constant temperature reaction for 18h ~ 24h, the temperature is lowered to room temperature at a rate of 0.7°C / min ~1°C / min, and blocky crystalline red phosphorus grows in the one section on the growth side.

2. The use according to claim 1, characterized in that: The mass ratio of nanoribbon crystalline red phosphorus to copper-rich metal salt is 5:1~2.

3. The use according to claim 1, characterized in that: Copper-rich metal salts are CuCl2, Cu(NO3)2, Cu(OAc)2.

4. The use according to claim 1, characterized in that: The wavelength of light in the illumination is 300-1200nm.

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