Synthesis method of nitrogen-doped biomass charcoal loaded CuS

Abstract

The invention belongs to the technical field of catalytic materials, and discloses a synthesis method of nitrogen-doped biomass charcoal loaded CuS. According to the invention, corncob powder and a nitrogen-doped biomass charcoal material derived from 2, 4, 6-triaminopyrimidine are used as a carrier, and CuS is loaded on the carrier; the obtained composite material is used for photocatalytic reduction of CO2 into CO, and has high photocatalytic activity and good stability. The method has the characteristics of simple operation method, simple process, greenness, environmental protection and the like.

Description

Technical Field

[0001] The present invention belongs to the field of catalytic materials, and specifically relates to a synthesis method of nitrogen-doped biomass carbon supported CuS. Background Art

[0002] As a non-toxic, low-cost, and chemically stable semiconductor material, metal sulfide has advantages such as strong light capture ability and narrow bandgap, and has good prospects in the application field of photocatalytic technology. Metal sulfide photocatalytic materials are mainly used for photocatalytic carbon dioxide reduction, hydrogen evolution, pollutant degradation, etc. However, metal sulfide has problems such as easy agglomeration and easy photocorrosion. Constructing a carrier for it is an effective way to inhibit agglomeration and photocorrosion. As a new type of non-metallic material, nitrogen-doped biomass carbon has unique potential in electron transfer and as a dispersion carrier. In addition, biomass carbon has characteristics such as high specific surface area, good stability, and wide light absorption range. Using nitrogen-doped biomass carbon as the carrier of CuS can not only reduce the agglomeration of CuS and increase the surface active sites, but also accelerate electron transfer and inhibit the photocorrosion of CuS, thereby improving the photocatalytic activity and stability to achieve efficient reduction of CO2.

[0003] Therefore, loading CuS on nitrogen-doped biomass carbon to improve the activity of photocatalytic reduction of CO2 to CO and the stability of CuS has extremely important application value, and there is no relevant report at present. Summary of the Invention

[0004] To solve the above technical problems, the present invention provides a synthesis method of nitrogen-doped biomass carbon supported CuS.

[0005] To solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A synthesis method of nitrogen-doped biomass carbon supported CuS includes the following steps:

[0007] S1. Put the corn cob powder obtained by evenly grinding corn cobs into deionized water, disperse it by ultrasonic wave to obtain a mixed dispersion liquid, centrifuge the obtained mixed dispersion liquid, wash it with ultrapure water, and dry it in an oven to obtain clean corn cob powder;

[0008] S2. Mix and grind the clean corn cob powder obtained in step (1) and 2,4,6-triaminopyrimidine in a mortar in proportion;

[0009] S3. Put the powder obtained by mixing and grinding in step (2) into a porcelain boat, program the temperature to the calcination temperature under a nitrogen atmosphere, calcine for a period of time and then cool to room temperature, and obtain nitrogen-doped biomass carbon after washing;

[0010] S4. Mix nitrogen-doped biomass carbon, CuCl solid, and thioacetamide in ultrapure water, stir for a period of time, and then carry out a hydrothermal reaction; after the reaction is completed, wash the product and dry it under vacuum to obtain a CuS sample supported on nitrogen-doped biomass carbon.

[0011] In step S1, the dosage ratio of corncob powder to deionized water is 10 g: 200 mL, and the ultrasonic time is 120 minutes.

[0012] In step S1, the centrifugation rate is 10000 revolutions per minute, the time is 5 minutes, and drying is carried out at 60 °C for 12 hours.

[0013] In step S2, the mass ratio of clean corncob powder to 2,4,6-triaminopyrimidine is 1:1, and the grinding time is 20 minutes.

[0014] In step S3, the calcination temperature is 400 - 500 °C, the calcination time is 1 - 4 hours, and the heating rate is 3 - 5 °C / min; and it is cooled to room temperature in a natural cooling manner under a N2 atmosphere.

[0015] In step S4, the mass ratio of nitrogen-doped biomass carbon, CuCl solid, and thioacetamide is 2: 2 - 10.5: 5 - 12.

[0016] In step S4, the temperature of the hydrothermal reaction is 140 - 200 °C; the time of the hydrothermal reaction is 12 - 48 hours.

[0017] In step S4, the washing method is: centrifugally wash the product with water, the rotation speed is 10000 revolutions per minute, and the time is 3 minutes.

[0018] In step S4, the temperature of vacuum drying is 50 - 70 °C, and the time is 10 - 15 hours.

[0019] Use the nitrogen-doped biomass carbon supported CuS prepared by the present invention as a composite catalyst for reducing CO2 under simulated sunlight.

[0020] The beneficial effects of the present invention are as follows:

[0021] (1) For the nitrogen-doped biomass carbon material derived from the corncob powder and 2,4,6-triaminopyrimidine selected in the present invention, the raw materials are cheap and easily available, reducing the preparation cost of the catalyst. The obtained CuS supported on nitrogen-doped biomass carbon has high photocatalytic activity and good stability.

[0022] (2) The present invention prepares a CuS material supported on nitrogen-doped biomass carbon, and the nitrogen-doped biomass carbon inhibits the aggregation and photocorrosion of metal sulfides. The preparation method has the characteristics of simple operation method, simple process, and environmental friendliness. Description of the Drawings

[0023] Figure 1 X-ray diffraction patterns of the product of Example 1, NBC, and CuS;

[0024] Figure 2 Scanning electron micrograph of the product of Example 1;

[0025] Figure 3 Transmission electron micrograph of the product of Example 1;

[0026] Figure 4 Comparison chart of the CO2 reduction performance of the products of Examples 1-3, NBC, and CuS under simulated sunlight conditions. Detailed implementation manners

[0027] To further understand the features, technical means, specific purposes, and functions achieved by the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0028] Example 1

[0029] A synthesis method of nitrogen-doped biomass carbon supported CuS, comprising the following steps:

[0030] S1. Weigh 10 grams of corn flour obtained by grinding corn cobs evenly and place it in a beaker containing 200 milliliters of deionized water. Ultrasonically disperse for 120 minutes to obtain a mixed dispersion. Centrifuge the obtained mixed dispersion at a rate of 10,000 revolutions per minute for 5 minutes, wash three times with ultrapure water, and dry in an oven at 60 °C for 12 hours to obtain clean corn cob powder.

[0031] S2. Weigh 0.3 grams of the above-mentioned clean corn cob powder and 0.3 grams of 2,4,6-triaminopyrimidine and place them in a mortar for thorough grinding for 20 minutes.

[0032] S3. Place the mixed and ground powder in a porcelain boat, heat the porcelain boat to 500 °C at a heating rate of 3 °C per minute under a nitrogen atmosphere, hold for 2 hours, and then naturally cool to room temperature. After washing, nitrogen-doped biomass carbon is obtained. Room temperature is the temperature in the range of 20 - 30 °C.

[0033] S4. Weigh 20 milligrams of nitrogen-doped biomass carbon, 52.3 milligrams of CuCl, and 59.6 milligrams of thioacetamide, disperse them in 40 milliliters of ultrapure water, stir for 30 minutes, and then hydrothermally react at 180 °C for 24 hours.

[0034] S5. Centrifuge and wash the product obtained in S4 with ultrapure water, and then place it in a vacuum drying oven and keep it at 60 °C for 12 hours to obtain a sample with CuS:NBC = 2:1.

[0035] Example 2

[0036] A synthesis method of nitrogen-doped biomass carbon-supported CuS material, comprising the following steps:

[0037] S1. Weigh 10 grams of corn flour obtained by uniformly grinding corn cobs and place it in a beaker containing 200 milliliters of deionized water. Ultrasonically disperse for 120 minutes to obtain a mixed dispersion. Centrifuge the obtained mixed dispersion at a rate of 10,000 revolutions per minute for 5 minutes, wash it three times with ultrapure water, and dry it in an oven at 60 °C for 12 hours to obtain clean corn cob powder.

[0038] S2. Weigh 0.3 grams of the above-mentioned clean corn cob powder and 0.3 grams of 2,4,6-triaminopyrimidine and place them in a mortar for thorough grinding for 20 minutes.

[0039] S3. Place the mixed and ground powder in a porcelain boat, heat the porcelain boat to 400 °C at a heating rate of 3 °C per minute under a nitrogen atmosphere, hold for 2 hours, and then naturally cool to room temperature. After washing, nitrogen-doped biomass carbon is obtained. Room temperature is the temperature in the range of 20 - 30 °C.

[0040] S4. Weigh 20 milligrams of nitrogen-doped biomass carbon, 26.2 milligrams of CuCl, and 29.8 milligrams of thioacetamide, disperse them in 40 milliliters of ultrapure water, stir for 30 minutes, and then hydrothermally react at 140 °C for 24 hours.

[0041] S5. Centrifuge and wash the product obtained in S4 with ultrapure water, and then place it in a vacuum drying oven and keep it at 60 °C for 12 hours to obtain a sample with CuS:NBC = 1:1.

[0042] Example 3

[0043] A synthesis method of nitrogen-doped biomass carbon-supported CuS material, comprising the following steps:

[0044] S1. Weigh 10 grams of corn flour obtained by uniformly grinding corn cobs and place it in a beaker containing 200 milliliters of deionized water. Ultrasonically disperse for 120 minutes to obtain a mixed dispersion. Centrifuge the obtained mixed dispersion at a rate of 10,000 revolutions per minute for 5 minutes, wash it three times with ultrapure water, and dry it in an oven at 60 °C for 12 hours to obtain clean corn cob powder.

[0045] S2. Weigh 0.3 grams of the above-mentioned clean corn cob powder and 0.3 grams of 2,4,6-triaminopyrimidine and place them in a mortar for thorough grinding for 20 minutes.

[0046] S3. Place the mixed and ground powder in a porcelain boat, heat the porcelain boat to 450 °C at a heating rate of 3 °C per minute under a nitrogen atmosphere, hold for 2 hours, and then naturally cool to room temperature. After washing, nitrogen-doped biomass carbon is obtained. Room temperature is the temperature in the range of 20 - 30 °C.

[0047] S4. Weigh 20 mg of nitrogen-doped biomass carbon, 104.6 mg of CuCl, and 119.1 mg of thioacetamide, disperse them in 40 mL of ultrapure water, stir for 30 minutes, and then hydrothermally react at 200 °C for 24 hours.

[0048] S5. Centrifuge and wash the product obtained in S4 with ultrapure water, then place it in a vacuum drying oven and keep it at 60 °C for 12 hours to obtain a sample with CuS:NBC = 4:1.

[0049] Comparative Example 1

[0050] S1. Weigh 10 g of corn flour ground evenly from corncobs, place it in a beaker containing 200 mL of deionized water, disperse it by ultrasonic treatment for 120 minutes to obtain a mixed dispersion. Centrifuge the obtained mixed dispersion at a rate of 10,000 revolutions per minute for 5 minutes, wash it three times with ultrapure water, and dry it in an oven at 60 °C for 12 hours.

[0051] S2. Weigh 0.3 g of the above dried sample and 0.3 g of 2,4,6-triaminopyrimidine, place them in a mortar, and grind them thoroughly for 20 minutes.

[0052] S3. Place the mixed and ground powder in a porcelain boat, heat the porcelain boat to 500 °C at a heating rate of 3 °C per minute in an N2 atmosphere, keep it for 2 hours, and then naturally cool it to room temperature. After washing, NBC is obtained.

[0053] Comparative Example 2

[0054] Weigh 198 mg of CuCl and 225.4 mg of thioacetamide, disperse them in 40 mL of ultrapure water, stir for 30 minutes, and then hydrothermally react at 180 °C for 24 hours to obtain a CuS monomer sample.

[0055] Next, the nitrogen-doped biomass carbon-supported CuS prepared in Example 1 was subjected to performance testing.

[0056] The product obtained in Example 1 was characterized using an X-ray diffractometer, as Figure 1 shown. It can be seen that the composite did not change the crystal structures of CuS and NBC, indicating that the nitrogen-doped biomass carbon-supported CuS was successfully synthesized.

[0057] Figure 2 is the scanning electron micrograph of the product obtained in Example 1, indicating that CuS is uniformly dispersed on the surface of NBC.

[0058] Figure 3 is the transmission electron micrograph of the product obtained in Example 1. It can be seen that there is an obvious boundary between CuS and NBC, and the lattice fringe spacing of CuS is 0.28 nm, corresponding to the (108) crystal plane of CuS.

[0059] The photocatalytic performance of the sample was mainly evaluated in a reactor filled with CO2 gas containing water. The reactor was made of quartz glass, and a xenon lamp (0.5 W / cm -2 ) was placed 5 cm above the reactor. Before the photocatalytic experiment, 25 mg of the catalyst was weighed and dispersed in a mixed solution of 2 mL of ultrapure water and 2 mL of triethanolamine and placed in the reactor. The reactor containing the mixed solution was placed on a magnetic stirrer. Under the condition of no light, the mixed solution was evenly stirred by the magnetic stirrer to achieve the adsorption-desorption equilibrium with CO2. After 30 minutes, the power of the xenon lamp was turned on to start the test. During the photocatalytic reaction, 1 mL of gas sample was taken every 1 hour and injected into the gas chromatograph, and the reaction was carried out for 4 hours. The gas samples at different time points were analyzed and detected by using a gas chromatograph equipped with a thermal conductivity and flame ionization detector.

[0060] The reduction performance of the product obtained in Example 1 and the biomass carbon for CO2 under simulated sunlight is shown in the appendix Figure 4 . The CO production in the CuS monomer reached 2.65 μmol / g, the CO production in the NBC monomer reached 3.84 μmol / g, the CO production in Example 1 reached 11.98 μmol / g, the CO production in Example 2 was 3.05 μmol / g, and the CO production in Example 3 was 6.52 μmol / g. It can be seen from this that the product prepared by the present invention has good photocatalytic effect.

Claims

1. A synthesis method of nitrogen-doped biomass carbon supported CuS, characterized in that, It includes the following steps: S1. Place the corn cob powder obtained by evenly grinding corn cobs into deionized water, perform ultrasonic dispersion to obtain a mixed dispersion liquid, centrifuge the obtained mixed dispersion liquid, wash it with ultrapure water, and dry it in an oven to obtain clean corn cob powder; S2. Mix and grind the clean corn cob powder obtained in step (1) and 2,4,6-triaminopyrimidine in a mortar in proportion; S3. Place the powder obtained by mixing and grinding in step (2) in a porcelain boat, program the temperature to the calcination temperature under a nitrogen atmosphere, calcine for a period of time and then cool to room temperature, and obtain nitrogen-doped biomass carbon after washing; S4. Mix nitrogen-doped biomass carbon, CuCl solid and thioacetamide in ultrapure water, stir for a period of time and then carry out a hydrothermal reaction; after the reaction is completed, wash the product and dry it under vacuum to obtain a nitrogen-doped biomass carbon supported CuS sample.

2. The synthesis method according to claim 1, wherein In step S1, the dosage ratio of corn cob powder to deionized water is 10 g: 200 mL, and the ultrasonic time is 120 minutes.

3. The synthesis method according to claim 1, characterized in that, In step S1, the centrifugation rate is 10000 revolutions per minute, the time is 5 minutes, and it is dried at 60 °C for 12 hours.

4. The synthesis method according to claim 1, characterized in that, In step S2, the mass ratio of clean corn cob powder to 2,4,6-triaminopyrimidine is 1:1, and the grinding time is 20 minutes.

5. The synthesis method according to claim 1, characterized in that, In step S3, the calcination temperature is 400 - 500 °C, the calcination time is 1 - 4 hours, and the heating rate is 3 - 5 °C / min; and it is cooled to room temperature in a natural cooling manner under a nitrogen atmosphere.

6. The synthesis method according to claim 1, characterized in that, In step S4, the mass ratio of nitrogen-doped biomass carbon, CuCl solid and thioacetamide is 2: 2 - 10.5: 5 - 12.

7. The synthesis method according to claim 1, wherein, In step S4, the temperature of the hydrothermal reaction is 140 - 200 °C; the time of the hydrothermal reaction is 12 - 48 hours.

8. The synthesis method according to claim 1, characterized in that, In step S4, the washing method is: centrifuge and wash the product, the rotation speed is 10000 r / min, and the time is 3 minutes.

9. The synthesis method according to claim 1, wherein, In step S4, the temperature of vacuum drying is 50 - 70 °C, and the time is 10 - 15 hours.

10. Use the CuS supported by nitrogen-doped biomass carbon prepared by the synthesis method described in any one of claims 1 - 9 as a composite catalyst for reducing CO2 under simulated sunlight.

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