Preparation method and application of boron-doped carbon nitride nanosheets modified with fullerene derivatives

Abstract

A preparation method and application of boron-doped carbon nitride nanosheets modified with fullerene derivatives, which relates to a preparation method and application of a photocatalyst. The purpose of the present invention is to solve the problems of slow electron dynamics and insufficient CO2 adsorption capacity in the subsequent catalytic reaction of existing boron-doped carbon nitride. Method: 1. Preparation of g-C3N4; 2. Preparation of boron-doped carbon nitride; 3. Acidification; 4. Preparation of hydroxylated fullerene C 60 ; V. Composite. A boron-doped carbon nitride nanosheet modified with a fullerene derivative is used to catalyze CO2 reduction. The present invention prepares a boron-doped carbon nitride nanosheet modified with a fullerene derivative, and utilizes hydroxyfullerene C 60 The functions of enriching electrons and activating CO2 by adsorption improve the electron transfer efficiency and CO2 adsorption capacity of boron-doped carbon nitride. The CO2 reduction rate can reach 37.25 μmol / g / h, which is 4.5 times the photocatalytic activity of UBCN.

Description

Technical Field

[0001] The present invention relates to a preparation method and application of a photocatalyst, and in particular to a preparation method and application of a boron-doped carbon nitride nanosheet modified with a fullerene derivative. Background Art

[0002] The combustion of fossil fuels produces a large amount of CO2, which has led to an increasingly serious global greenhouse effect. On the other hand, the reserves of fossil fuels are limited, but the global demand for energy is growing, which has led to energy shortages. Using CO2 as a raw material to produce high-calorific value fuels such as CO has become one of the effective solutions to the environmental problems caused by excessive CO2 emissions and the energy shortage caused by limited fossil fuels. Solar energy has the advantages of being green, clean, environmentally friendly, pollution-free, and "inexhaustible". Semiconductor photocatalytic technology has mild reaction conditions and low waste emissions. Therefore, photocatalytic technology that uses solar energy to drive the catalytic reduction of CO2 into high-value chemicals is expected to achieve a "carbon cycle" and is considered to be a technology with broad development prospects.

[0003] Among numerous photocatalyst materials, polymer semiconductor graphene carbon nitride (g-C3N4) is widely used due to its visible light response, non-toxicity, metal-free nature, zero secondary pollution, and low cost. However, its inherent poor charge separation also affects its photocatalytic efficiency. Boron-doped carbon nitride (UBCN) can improve the charge separation efficiency of existing carbon nitride materials to a certain extent, but it also has key issues that need to be addressed, such as slow electron dynamics and insufficient CO2 adsorption capacity during subsequent catalytic reactions. Summary of the Invention

[0004] The purpose of the present invention is to solve the problems of slow electron dynamics and insufficient CO2 adsorption capacity in the subsequent catalytic reaction of existing boron-doped carbon nitride, and to provide a preparation method and application of boron-doped carbon nitride nanosheets modified with fullerene derivatives.

[0005] A method for preparing boron-doped carbon nitride nanosheets modified with fullerene derivatives is completed by the following steps:

[0006] 1. Preparation of g-C3N4:

[0007] Put urea in a crucible, then put the crucible into a muffle furnace, heat and calcine for a period of time, and naturally cool to room temperature to obtain reaction product I; wash and dry the reaction product I to obtain g-C3N4;

[0008] 2. Preparation of boron-doped carbon nitride:

[0009] First, sodium borohydride is ground in a mortar, and then g-C3N4 is added, mixed, and ground again to obtain a mixed powder; the mixed powder is placed in a porcelain boat, which is then wrapped with tin foil and placed in a tube furnace. Nitrogen is introduced into the tube furnace, and the tube furnace is heated and calcined under a nitrogen atmosphere. After naturally cooling to room temperature, reaction product II is obtained; reaction product II is washed and dried to obtain boron-doped carbon nitride;

[0010] 3. Acidification:

[0011] dissolving boron-doped carbon nitride in a nitric acid solution, stirring until uniformly dispersed, heating in a water bath at a constant temperature for a period of time, cooling and centrifuging, discarding the supernatant, and collecting the solid matter; washing the solid matter, drying, and obtaining acidified boron-doped carbon nitride;

[0012] 4. Preparation of Hydroxylated Fullerene C 60 :

[0013] ①、Fullerene C 60 Add toluene and dissolve under ultrasonication to obtain a purple solution; add NaOH solution, tetrabutylammonium hydroxide and H2O2 liquid to the purple solution under stirring, stir and react for a period of time, discard the upper colorless transparent liquid, and collect the lower brown liquid; add methanol to the lower brown liquid and centrifuge, discard the supernatant, and collect solid substance I;

[0014] ②. Add deionized water to the collected solid material I and dissolve it by ultrasonication. Then add methanol and centrifuge to collect the solid material II.

[0015] ③ Repeat step 4② 2 to 4 times to obtain a dark brown solid, and then dry it to obtain hydroxylated fullerene C 60 ;

[0016] 5. Compound:

[0017] Hydroxylated fullerene C 60 The acidified boron-doped carbon nitride is dispersed in deionized water, stirred for a period of time, and then heated in a water bath to evaporate the solvent. The obtained solid is the boron-doped carbon nitride nanosheet modified with the fullerene derivative.

[0018] Boron-doped carbon nitride nanosheets modified with a fullerene derivative are used to catalyze CO2 reduction.

[0019] Principle of the present invention:

[0020] Fullerene C 60 It is a kind of fullerene derivative, with good chemical stability, large specific surface area, good electrical conductivity, unique three-dimensional structure and other characteristics. It has a good enrichment effect on electrons. The modified hydroxyl groups increase the hydrophilicity of the material and make hydroxyl fullerene C 60It can form a closer interface connection with boron-doped carbon nitride (UBCN), thus improving the transfer efficiency of photogenerated electrons in the photocatalyst. Secondly, it has been found that hydroxyfullerene C 60 The modification of fullerene derivatives can effectively enhance the adsorption capacity of photocatalysts for CO2 and improve the efficiency of CO2 reduction in subsequent catalytic reactions; therefore, boron-doped carbon nitride nanosheets modified with fullerene derivatives (C 60 OH / UBCN) photocatalyst is used to accelerate the electron dynamics of the photocatalyst and improve the adsorption capacity of CO2.

[0021] Advantages of the present invention:

[0022] The present invention aims to solve the key problems of slow electron dynamics and insufficient CO2 adsorption capacity of boron-doped carbon nitride itself, and prepares boron-doped carbon nitride nanosheets modified with fullerene derivatives. 60 The functions of enriching electrons and adsorbing and activating CO2 improve the electron transfer efficiency and CO2 adsorption ability of boron-doped carbon nitride (UBCN). The CO2 reduction CO yield can reach 37.25 μmol / g / h, which is 4.5 times the photocatalytic activity of unmodified UBCN. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Transmission electron microscopy images of boron-doped carbon nitride nanosheets modified with fullerene derivatives prepared in Example 1, where the scale of (a) is 20 nm and the scale of (b) is 2 nm;

[0024] Figure 2 XRD patterns of boron-doped carbon nitride and fullerene derivative-modified boron-doped carbon nitride nanosheets prepared in Example 1;

[0025] Figure 3 Boron-doped carbon nitride and hydroxyfullerene C prepared in Example 1 60 and Raman spectra of boron-doped carbon nitride nanosheets modified with fullerene derivatives;

[0026] Figure 4 The hydroxyl radical test spectra of boron-doped carbon nitride and boron-doped carbon nitride nanosheets modified with fullerene derivatives prepared in Examples 1 to 4;

[0027] Figure 5 Fluorescence spectra of boron-doped carbon nitride and boron-doped carbon nitride nanosheets modified with fullerene derivatives prepared in Examples 1 to 4;

[0028] Figure 6 Electrochemical reduction curve of boron-doped carbon nitride and fullerene derivative-modified boron-doped carbon nitride nanosheets prepared in Example 1 under CO2 conditions;

[0029] Figure 7 CO2 adsorption isotherm of boron-doped carbon nitride and fullerene derivative-modified boron-doped carbon nitride nanosheets prepared in Example 1;

[0030] Figure 8 The photocatalytic CO2 reduction activity of boron-doped carbon nitride nanosheets modified with boron-doped carbon nitride and fullerene derivatives prepared in Examples 1 to 4. DETAILED DESCRIPTION

[0031] Specific embodiment 1: In this embodiment, a method for preparing a boron-doped carbon nitride nanosheet modified with a fullerene derivative is completed by the following steps:

[0032] 1. Preparation of g-C3N4:

[0033] Put urea in a crucible, then put the crucible into a muffle furnace, heat and calcine for a period of time, and naturally cool to room temperature to obtain reaction product I; wash and dry the reaction product I to obtain g-C3N4;

[0034] 2. Preparation of Boron-doped Carbon Nitride:

[0035] First, sodium borohydride is ground in a mortar, and then g-C3N4 is added, mixed, and ground again to obtain a mixed powder; the mixed powder is placed in a porcelain boat, which is then wrapped with tin foil and placed in a tube furnace. Nitrogen is introduced into the tube furnace, and the tube furnace is heated and calcined under a nitrogen atmosphere. After naturally cooling to room temperature, reaction product II is obtained; reaction product II is washed and dried to obtain boron-doped carbon nitride;

[0036] 3. Acidification:

[0037] dissolving boron-doped carbon nitride in a nitric acid solution, stirring until uniformly dispersed, heating in a water bath at a constant temperature for a period of time, cooling and centrifuging, discarding the supernatant, and collecting the solid matter; washing the solid matter, drying, and obtaining acidified boron-doped carbon nitride;

[0038] 4. Preparation of Hydroxylated Fullerene C 60 :

[0039] ①、Fullerene C 60 Add toluene and dissolve under ultrasonication to obtain a purple solution; add NaOH solution, tetrabutylammonium hydroxide and H2O2 liquid to the purple solution under stirring, stir and react for a period of time, discard the upper colorless transparent liquid, and collect the lower brown liquid; add methanol to the lower brown liquid and centrifuge, discard the supernatant, and collect solid substance I;

[0040] ②. Add deionized water to the collected solid material I and dissolve it by ultrasonication. Then add methanol and centrifuge to collect the solid material II.

[0041] ③ Repeat step 4② 2 to 4 times to obtain a dark brown solid, and then dry it to obtain hydroxylated fullerene C 60 ;

[0042] 5. Compound:

[0043] Hydroxylated fullerene C 60 The acidified boron-doped carbon nitride is dispersed in deionized water, stirred for a period of time, and then heated in a water bath to evaporate the solvent. The obtained solid is the boron-doped carbon nitride nanosheet modified with the fullerene derivative.

[0044] Specific embodiment 2: This embodiment differs from specific embodiment 1 in that the heating rate in step 1 is 0.5°C / min to 1°C / min; the calcination temperature in step 1 is 550°C to 600°C, and the calcination time is 2 to 3 hours; and in step 1, reaction product I is centrifugally washed 3 to 5 times with deionized water and anhydrous ethanol, followed by drying in an oven at 80°C to 90°C. Other steps are the same as those in specific embodiment 1.

[0045] Specific embodiment three: This embodiment differs from specific embodiment one or two in that: the mass ratio of sodium borohydride to g-C3N4 in step two is (0.2-0.3):(0.3-0.5); the heating rate in step two is 5°C / min-10°C / min; the calcination temperature in step two is 480°C-500°C, and the calcination time is 1h-3h. The other steps are the same as specific embodiment one or two.

[0046] Specific Embodiment 4: This embodiment differs from Specific Embodiments 1 to 3 in that the flow rate of nitrogen introduced into the tube furnace in step 2 is 80 mL / min to 100 mL / min; and in step 2, reaction product II is centrifugally washed 2 to 5 times with deionized water and then anhydrous ethanol, followed by drying in an oven at 80°C to 90°C. The other steps are the same as Specific Embodiments 1 to 3.

[0047] Specific Embodiment 5: This embodiment differs from Specific Embodiments 1 to 4 in that the concentration of the nitric acid solution in step 3 is 5 mol / L; the volume ratio of the boron-doped carbon nitride to the nitric acid solution in step 3 is 0.5 g:50 mL; and the water bath constant temperature heating in step 3 is at 70°C to 80°C for 2 to 3 hours. Other steps are the same as Specific Embodiments 1 to 4.

[0048] Specific Embodiment 6: This embodiment differs from Specific Embodiments 1 to 5 in that the centrifuge speed in step 3 is 4000 to 5000 rpm; the solid material is centrifugally cleaned 2 to 5 times using deionized water and anhydrous ethanol, followed by drying in an oven at 80°C to 90°C. The other steps are the same as Specific Embodiments 1 to 5.

[0049] Specific embodiment 7: This embodiment differs from specific embodiments 1 to 6 in that: the fullerene C in step 4① 60 The mass ratio of toluene to the volume ratio of 0.05g:50mL; the concentration of the NaOH solution in step 4 (1) is 5mol / L to 6mol / L; the volume ratio of toluene, NaOH solution, tetrabutylammonium hydroxide, and H2O2 liquid in step 4 (1) is 50:2:1:5. The other steps are the same as those in specific embodiments 1 to 6.

[0050] Specific embodiment 8: This embodiment differs from specific embodiments 1 to 7 in that: the stirring reaction time in step 4 (1) is 35 to 45 minutes; the concentration of the H2O2 liquid in step 4 (1) is 20% to 30%; the centrifugation speed in step 4 (1) is 4000 to 5000 r / min, and the centrifugation time is 5 to 10 minutes; the mass volume ratio of the solid material I, deionized water, and methanol in step 4 (2) is 0.06 g:2 mL:80 mL; the centrifugation speed in step 4 (2) is 4000 to 5000 r / min, and the centrifugation time is 5 to 10 minutes; and the drying temperature in step 4 (3) is 40°C to 60°C. The other steps are the same as specific embodiments 1 to 7.

[0051] Specific embodiment 9: This embodiment differs from specific embodiments 1 to 8 in that: the hydroxylated fullerene C in step 5 60 The mass volume ratio of the acidified boron-doped carbon nitride to deionized water is 0.0004 g:0.05 g:(20 mL to 25 mL); the stirring speed in step 5 is 400 to 500 r / min for 10 to 12 hours; and the mixture is heated in a water bath at 50° C. to 55° C. until the solvent is evaporated. The other steps are the same as those in specific embodiments 1 to 8.

[0052] Specific embodiment 10: This embodiment is a fullerene derivative modified boron-doped carbon nitride nanosheet used to catalyze CO2 reduction.

[0053] The following examples are used to verify the beneficial effects of the present invention:

[0054] Example 1: A method for preparing boron-doped carbon nitride nanosheets modified with fullerene derivatives is carried out according to the following steps:

[0055] 1. Preparation of g-C3N4:

[0056] 35 g of urea was placed in a crucible, and the crucible was placed in a muffle furnace. The temperature was increased to 550°C at a heating rate of 0.5°C / min, and the mixture was calcined at 550°C for 3 hours. The mixture was naturally cooled to room temperature to obtain reaction product I. The reaction product I was centrifuged and washed three times with deionized water and anhydrous ethanol, and then dried in an oven at 80°C to obtain g-C3N4.

[0057] 2. Preparation of Boron-doped Carbon Nitride:

[0058] First, 0.24 g of sodium borohydride was ground in a mortar, and then 0.4 g of g-C3N4 was added, mixed and ground again to obtain a mixed powder; the mixed powder was placed in a porcelain boat, and then the outside of the porcelain boat was wrapped with tin foil, and then placed in a tube furnace, and 80 mL / min of nitrogen was introduced into the tube furnace. Under the protection of a nitrogen atmosphere, the tube furnace was heated to 490°C at a heating rate of 10°C / min, and the mixture was calcined at 490°C for 2 hours. After naturally cooling to room temperature, a reaction product II was obtained; the reaction product II was first centrifuged and washed three times with deionized water, then centrifuged and washed twice with anhydrous ethanol, and then dried in an oven at a temperature of 80°C to obtain boron-doped carbon nitride (UBCN);

[0059] 3. Acidification:

[0060] 0.5 g of boron-doped carbon nitride was dissolved in 50 mL of 5 mol / L nitric acid solution, stirred until uniformly dispersed, heated in a water bath to 70° C., and heated in a water bath at 70° C. for 2 h. After cooling, the mixture was centrifuged at a speed of 4000 r / min, the supernatant was discarded, and the solid matter was collected; the collected solid matter was first centrifuged and washed four times with deionized water, then washed twice with anhydrous ethanol, and then dried in an oven at 80° C. to obtain acidified boron-doped carbon nitride;

[0061] 4. Preparation of Hydroxylated Fullerene C 60 :

[0062] ①, 0.05g fullerene C 60Add to 50 mL of toluene, cover with plastic wrap, and completely dissolve by ultrasonication to obtain a purple solution; under stirring conditions, add 2 mL of 6 mol / L NaOH solution, 1 mL of tetrabutylammonium hydroxide, and 5 mL of H2O2 liquid to the purple solution, stir and react for 45 minutes, discard the upper colorless transparent liquid, and collect the lower brown liquid; add 80 mL of methanol to the lower brown liquid, centrifuge at 4000 r / min for 5 minutes, discard the supernatant, and collect solid substance I;

[0063] The concentration of the H2O2 liquid in step 4① is 30%;

[0064] ②. Add deionized water to the collected solid material I and dissolve it by ultrasonication. Then add methanol and centrifuge at 4000 rpm for 5 minutes. Discard the supernatant and collect the solid material II.

[0065] The mass volume ratio of the solid substance I described in step 4②, deionized water and methanol is 0.06g:2mL:80mL;

[0066] ③ Repeat step 4② 3 times to obtain a dark brown solid, and then dry it in an oven at 40℃ to obtain hydroxylated fullerene C 60 (C 60 OH);

[0067] 5. Compound:

[0068] 0.0004 g of hydroxylated fullerene C 60 and 0.05 g of acidified boron-doped carbon nitride were dispersed in 20 mL of deionized water, stirred for 12 h, and then heated in a 50 ° C water bath to evaporate the solvent. The obtained solid was the boron-doped carbon nitride nanosheet modified with fullerene derivatives (0.8C 60 OH / UBCN).

[0069] Example 2: The difference between this example and example 1 is that 0.0002 g of hydroxylated fullerene C 60 and 0.05 g of acidified boron-doped carbon nitride were dispersed in 20 mL of deionized water, stirred for 12 h, and then heated in a 50 ° C water bath to evaporate the solvent. The obtained solid was the fullerene derivative-modified boron-doped carbon nitride nanosheet (0.4C 60 OH / UBCN).

[0070] Example 3: The difference between this example and example 1 is that 0.0006 g of hydroxylated fullerene C 60 and 0.05 g of acidified boron-doped carbon nitride were dispersed in 20 mL of deionized water, stirred for 12 h, and then heated in a 50 ° C water bath to evaporate the solvent. The obtained solid was the boron-doped carbon nitride nanosheet modified with fullerene derivatives (1.2C60 OH / UBCN).

[0071] Example 4: The difference between this example and example 1 is that 0.0008 g of hydroxylated fullerene C 60 and 0.05 g of acidified boron-doped carbon nitride were dispersed in 20 mL of deionized water, stirred for 12 h, and then heated in a 50 ° C water bath to evaporate the solvent. The obtained solid was the boron-doped carbon nitride nanosheet modified with fullerene derivatives (1.6C 60 OH / UBCN).

[0072] Figure 1 Transmission electron micrographs of boron-doped carbon nitride nanosheets modified with fullerene derivatives prepared in Example 1, where the scale of (a) is 20 nm and the scale of (b) is 2 nm;

[0073] from Figure 1 (a) It can be seen that the boron-doped carbon nitride nanosheets (0.8C) modified with fullerene derivatives prepared in Example 1 60 OH / UBCN) presents an ultra-thin layer structure; at the 2nm scale, C 60 OH exists ( Figure 1 (b)).

[0074] Figure 2 XRD patterns of boron-doped carbon nitride and fullerene derivative-modified boron-doped carbon nitride nanosheets prepared in Example 1;

[0075] from Figure 2 It can be seen that the weak diffraction peak at 13.1° is attributed to the repeated tris-triazine unit (100) in the plane, and there is a strong and sharp diffraction peak at 27.3°, which corresponds to the interlayer stacking (002) structure. 60 Comparing the UBCN modified with OH and the unmodified UBCN, the XRD patterns show that the diffraction peaks have not moved, which indicates that C 60 The introduction of OH has little effect on the crystal structure of UBCN.

[0076] In order to verify that hydroxyl C 60 Whether it is successfully modified on UBCN, UBCN, C 60 OH, 0.8C 60 OH / UBCN conducted Raman tests, such as Figure 3 As shown;

[0077] Figure 3 Boron-doped carbon nitride and hydroxyfullerene C prepared in Example 1 60 and Raman spectra of boron-doped carbon nitride nanosheets modified with fullerene derivatives;

[0078] from Figure 3 It can be seen that different samples have different -1 and 1580cm -1 There are two bands near the hydroxyfullerene C, which belong to the D band and the G band respectively. 60 The D and G bands of the modified UBCN sample are both located at C 60 Between the D band and G band of OH and UBCN, it indicates that at 0.8C 60 C in OH / UBCN materials 60 A strong interaction is generated between OH and UBCN.

[0079] The TEM, XRD and Raman spectra of the samples showed that C 60 Successful synthesis of OH / UBCN.

[0080] In terms of performance, the effects of UBCN and different amounts of hydroxyfullerene C 60 The modified UBCN was tested for hydroxyl radicals, such as Figure 4 As shown;

[0081] Figure 4 The hydroxyl radical test spectra of boron-doped carbon nitride and boron-doped carbon nitride nanosheets modified with fullerene derivatives prepared in Examples 1 to 4;

[0082] from Figure 4 It can be seen that: Hydroxyfullerene C 60 The fluorescence signals of 7-hydroxycoumarin produced by the modified UBCN samples were stronger than those of UBCN, indicating that they had a stronger ability to promote charge separation.

[0083] Figure 5 Fluorescence spectra of boron-doped carbon nitride and boron-doped carbon nitride nanosheets modified with fullerene derivatives prepared in Examples 1 to 4;

[0084] Figure 5 The fluorescence spectrum shown also confirms this point. 60 The fluorescence signal of the modified UBCN was greatly reduced, which was consistent with the results of the hydroxyl radical test, and the optimal modification amount was 0.8C 60 OH / UBCN.

[0085] Cut the purchased conductive glass into the desired size and shape, then wash it and set aside. Next, prepare the paste solution; the method is to mix 0.1mL of naphthol and 0.9mL of anhydrous ethanol, stir, add 0.1g of sample, and continue stirring for a long time until the solution is completely dispersed. Then, apply the stirred solution on the FTO glass sheet, place it in a vacuum drying oven at 60℃ until it is dry, and then place it in the electrochemical device for testing. Figure 6 As shown, for UBCN and C 60 The OH / UBCN samples were subjected to electrochemical reduction tests.

[0086] Figure 6 Electrochemical reduction curve of boron-doped carbon nitride and fullerene derivative-modified boron-doped carbon nitride nanosheets prepared in Example 1 under CO2 conditions;

[0087] from Figure 6 It can be seen that: 0.8C 60 OH / UBCN has a smaller onset potential than UBCN, indicating that C 60 In addition to its ability to capture photogenerated electrons, OH also has the catalytic ability to activate CO2 molecules.

[0088] Figure 7 CO2 adsorption isotherm of boron-doped carbon nitride and fullerene derivative-modified boron-doped carbon nitride nanosheets prepared in Example 1;

[0089] Figure 7 Indicates that hydroxyl C 60 It has the ability to promote the UBCN photocatalyst to adsorb more CO2.

[0090] First, 0.01g of sample was dissolved in 10mL of deionized water. In order to remove the gas in the container, high-purity CO2 gas was introduced into the reaction vessel by bubbling water. The stirring state was maintained during this process for 20min to saturate the system with CO2. Then the introduction of CO2 was stopped and the stirring was turned off to allow CO to fully contact the reactants. The light source for illumination was a 300W xenon lamp. A fixed volume (0.25mL) of gas was extracted from the reaction pool at regular intervals and the extracted gas was injected into a gas chromatograph to analyze the concentration of CO. The instrument model was (GC-7920). 60 The ability of the modified UBCN to reduce CO2 is also greatly improved due to its ability to capture electrons and adsorb CO2. Figure 8 As shown;

[0091] Figure 8 The photocatalytic CO2 reduction activity of boron-doped carbon nitride nanosheets modified with boron-doped carbon nitride and fullerene derivatives prepared in Examples 1 to 4.

[0092] from Figure 8 It can be seen that: Hydroxyfullerene C 60 The modified UBCN has stronger CO2 reduction activity than UBCN, and the sample with the optimal modification amount has the strongest CO2 reduction ability, which is consistent with the above-mentioned charge separation ability test results.

Claims

1. A method for preparing boron-doped carbon nitride nanosheets modified with fullerene derivatives, characterized in that The preparation method is completed according to the following steps:

1. Preparation of g-C3N4: Put urea in a crucible, then put the crucible into a muffle furnace, heat and calcine for a period of time, and naturally cool to room temperature to obtain reaction product I; wash and dry the reaction product I to obtain g-C3N4; 2. Preparation of Boron-doped Carbon Nitride: First, sodium borohydride is ground in a mortar, and then g-C3N4 is added, mixed, and ground again to obtain a mixed powder; the mixed powder is placed in a porcelain boat, which is then wrapped with tin foil and placed in a tube furnace. Nitrogen is introduced into the tube furnace, and the tube furnace is heated and calcined under a nitrogen atmosphere. After naturally cooling to room temperature, reaction product II is obtained; reaction product II is washed and dried to obtain boron-doped carbon nitride; 3. Acidification: dissolving boron-doped carbon nitride in a nitric acid solution, stirring until uniformly dispersed, heating in a water bath at a constant temperature for a period of time, cooling and centrifuging, discarding the supernatant, and collecting the solid matter; washing the solid matter, drying, and obtaining acidified boron-doped carbon nitride; The concentration of the nitric acid solution described in step 3 is 5 mol / L; The volume ratio of the boron-doped carbon nitride to the nitric acid solution in step 3 is 0.5 g:50 mL; The water bath constant temperature heating described in step 3 is 70°C to 80°C for 2h to 3h; 4. Preparation of Hydroxylated Fullerene C 60 : ①、Fullerene C 60 Add toluene and dissolve by ultrasonication to obtain a purple solution; add NaOH solution, tetrabutylammonium hydroxide and H2O2 liquid to the purple solution under stirring, stir and react for a period of time, discard the upper colorless transparent liquid, and collect the lower brown liquid; add methanol to the lower brown liquid and centrifuge, discard the supernatant, and collect solid substance I; Fullerene C described in step 4① 60 The mass ratio of toluene is 0.05g:50mL; The concentration of the NaOH solution in step 4① is 5 mol / L to 6 mol / L; In step 4①, the volume ratio of toluene, NaOH solution, tetrabutylammonium hydroxide and H2O2 liquid is 50:2:1:5; ②. Add deionized water to the collected solid material I and dissolve it by ultrasonication. Then add methanol and centrifuge to collect the solid material II. ③ Repeat step 4② 2 to 4 times to obtain a dark brown solid, and then dry it to obtain hydroxylated fullerene C 60 ; 5. Compound: Hydroxylated fullerene C 60 The acidified boron-doped carbon nitride is dispersed in deionized water, stirred for a period of time, and then heated in a water bath until the solvent is evaporated to obtain a solid which is a boron-doped carbon nitride nanosheet modified with a fullerene derivative; The hydroxylated fullerene C described in step 5 60 The mass volume ratio of acidified boron-doped carbon nitride and deionized water is 0.0004g:0.05g:(20mL~25mL).

2. The method for preparing a fullerene derivative-modified boron-doped carbon nitride nanosheet according to claim 1, characterized in that The heating rate in step 1 is 0.5°C / min to 1°C / min; the calcination temperature in step 1 is 550°C to 600°C, and the calcination time is 2h to 3h; in step 1, the reaction product I is centrifuged and washed 3 to 5 times with deionized water and anhydrous ethanol, and then dried in an oven at a temperature of 80°C to 90°C.

3. The method for preparing a fullerene derivative-modified boron-doped carbon nitride nanosheet according to claim 1, characterized in that The mass ratio of sodium borohydride to g-C3N4 described in step 2 is (0.2~0.3):(0.3~0.5); the heating rate described in step 2 is 5℃ / min~10℃ / min; the calcination temperature described in step 2 is 480℃~500℃, and the calcination time is 1h~3h.

4. The method for preparing a fullerene derivative-modified boron-doped carbon nitride nanosheet according to claim 1, characterized in that The flow rate of nitrogen introduced into the tubular furnace in step 2 is 80 mL / min to 100 mL / min; in step 2, the reaction product II is centrifuged and washed 2 to 5 times with deionized water and anhydrous ethanol, and then dried in an oven at a temperature of 80°C to 90°C.

5. The method for preparing a fullerene derivative-modified boron-doped carbon nitride nanosheet according to claim 1, characterized in that The centrifugal speed in step 3 is 4000 r / min to 5000 r / min; in step 3, the solid matter is centrifugally cleaned 2 to 5 times with deionized water and anhydrous ethanol in sequence, and then dried in an oven at a temperature of 80°C to 90°C.

6. The method for preparing a fullerene derivative-modified boron-doped carbon nitride nanosheet according to claim 1, characterized in that The stirring reaction time described in step 4① is 35min to 45min; the concentration of the H2O2 liquid described in step 4① is 20% to 30%; the centrifugal speed described in step 4① is 4000r / min to 5000r / min, and the centrifugal time is 5min to 10min; the mass volume ratio of the solid substance I described in step 4②, deionized water and methanol is 0.06g:2mL:80mL; the centrifugal speed described in step 4② is 4000r / min to 5000r / min, and the centrifugal time is 5min to 10min; the drying temperature described in step 4③ is 40℃ to 60℃.

7. The method for preparing a fullerene derivative-modified boron-doped carbon nitride nanosheet according to claim 1, characterized in that The stirring speed in step 5 is 400 r / min to 500 r / min, and the stirring time is 10 h to 12 h; in step 5, the mixture is heated in a water bath at a temperature of 50° C. to 55° C. until the solvent is evaporated.

8. Use of a boron-doped carbon nitride nanosheet modified with a fullerene derivative prepared by the preparation method according to claim 1, characterized in that Boron-doped carbon nitride nanosheets modified with a fullerene derivative are used to catalyze CO2 reduction.

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