Janus nanofiber heterojunction photocatalyst modified by carbon nitride nanosheets
阅读说明：本技术 氮化碳纳米片修饰的Janus纳米纤维异质结光催化剂 (Janus nanofiber heterojunction photocatalyst modified by carbon nitride nanosheets ) 是由 董相廷 孙凤 于文生 谢云蕊 齐海娜 马千里 李丹 杨颖� 于 2021-07-20 设计创作，主要内容包括：本发明涉及氮化碳纳米片修饰的Janus纳米纤维异质结光催化剂,属于纳米材料制备技术领域。本发明包括四个步骤：(1)配制纺丝液；(2)共轭电纺技术制备[TiO-(2)/PAN]//[(NH-(4))-(10)W-(12)O-(41)/Bi(NO-(3))-(3)/柠檬酸/PAN]Janus纳米纤维膜；(3)热处理制备[TiO-(2)/C]//[Bi-(2)WO-(6)/C]Janus纳米纤维膜；(4)利用尿素气化通过气固相反应制备g-C-(3)N-(4)纳米片修饰的[TiO-(2)/C]//[Bi-(2)WO-(6)/C]Janus纳米纤维异质结光催化剂。该催化剂具有光催化分解水产氢和光降解亚甲基蓝双功能。本发明的方法简单易行,可以批量生产,该新型光催化剂具有广阔的应用前景。(The invention relates to a Janus nanofiber heterojunction photocatalyst modified by carbon nitride nanosheets, and belongs to the technical field of preparation of nanomaterials. The invention comprises four steps: (1) preparing a spinning solution; (2) conjugated electrospinning technology for preparing [ TiO ] 2 /PAN]//[(NH 4 ) 10 W 12 O 41 /Bi(NO 3 ) 3 Citric acid/PAN]A Janus nanofiber membrane; (3) thermal treatment preparation of [ TiO ] 2 /C]//[Bi 2 WO 6 /C]A Janus nanofiber membrane; (4) preparation of g-C by gas-solid phase reaction by gasification of urea 3 N 4 Nanosheet-modified [ TiO 2 /C]//[Bi 2 WO 6 /C]Janus nanofiber heterojunction photocatalyst. The catalyst has double functions of photocatalytic water decomposition to produce hydrogen and photodegradation of methylene blue. The method of the invention is simple and easy to implementThe novel photocatalyst can be produced in batch, and has wide application prospect.)
1. The Janus nanofiber heterojunction photocatalyst modified by the carbon nitride nanosheets is characterized by comprising highly dispersed g-C3N4Nanosheet modified in [ TiO ]2/C]//[Bi2WO6/C]The Janus nanofiber has the advantages that the Janus nanofiber surface is formed, the diameter of a single nanofiber in the Janus nanofiber is 370 +/-4 nm, and the Janus nanofiber has good photocatalytic hydrogen production and organic dye methylene blue degradation dual-function characteristics.
2. The preparation method of the Janus nanofiber heterojunction photocatalyst modified by the carbon nitride nanosheets as claimed in claim 1, wherein the Janus nanofiber heterojunction photocatalyst modified by the carbon nitride nanosheets is prepared by using a positive high-voltage direct-current power supply, a negative high-voltage direct-current power supply and an aluminum rotary drum as a receiving device and using a conjugated electrospinning technology, and the preparation method comprises the following steps:
(1) preparing spinning solution
0.6g of TiO with a particle size of 25nm2Nanocrystalline, 2.0g PAN dispersed in 20.0g DMF, stirring continuously at 60 ℃ until a homogeneous dope, called dope A, is formed; 0.3042g of (NH)4)10W12O41And 0.5044g citric acid into appropriate amount of distilled water, heating to evaporate to form viscous jelly, and sequentially adding 20.0g DMF, 1.1646g Bi (NO)3)3·5H2O and 2.0g PAN are stirred at 60 ℃ to form uniform spinning solution, namely spinning solution B;
(2) preparation of [ TiO ]2/PAN]//[(NH4)10W12O41/Bi(NO3)3Citric acid/PAN]Janus nanofiber membrane
Respectively transferring the spinning solution A and the spinning solution B into a plastic injector with a stainless steel needle head, adopting a positive high-voltage direct-current power supply, a negative high-voltage direct-current power supply, horizontally placing a cylindrical aluminum rotary drum with the length of 20cm and the diameter of 7cm, rotating at 1200r/min, applying a positive voltage and a negative voltage of 8.5kV, and enabling the flow rate of the spinning solution to be 0.8mL h-1The distance between the needle point and the rotary drum of the collecting device is 16cm, and conjugated electrospinning is carried out at room temperature to obtain the TiO2/PAN]//[(NH4)10W12O41/Bi(NO3)3Citric acid/PAN]A Janus nanofiber membrane;
(3) preparation of [ TiO ]2/C]//[Bi2WO6/C]Janus nanofiber membrane
To make g-C3N4Uniformly growing the TiO on the surface of the Janus nano-fiber in the gas-solid phase reaction process2/PAN]//[(NH4)10W12O41/Bi(NO3)3Citric acid/PAN]Janus nanofiber membrane was cut to a size of 1X 1cm2Placing the small blocks into a tube furnace, and then placing the small blocks in the air atmosphere at 1 ℃ for min-1The temperature rise rate of (2) is increased to 270 ℃ and the temperature is maintained for 1h, and then the temperature is increased to 2 ℃ per minute under the nitrogen atmosphere-1Heating to 800 deg.C, maintaining the temperature and carbonizing for 2h, and naturally cooling to room temperature to obtain [ TiO ]2/C]//[Bi2WO6/C]A Janus nanofiber membrane;
(4) preparation of g-C3N4Nanosheet-modified [ TiO2/C]//[Bi2WO6/C]Janus nanofiber heterojunction photocatalyst
Preparation of g-C by gas-solid phase reaction3N4Nanosheet-modified [ TiO2/C]//[Bi2WO6/C]Janus nanofiber heterojunction photocatalyst is prepared by placing a small porcelain crucible in a porcelain boat, uniformly dispersing urea powder with the mass of 2.5g at the bottom of the porcelain boat and the porcelain crucible, and taking a circular aluminum foil with holes as [ TiO ]2/C]//[Bi2WO6/C]A Janus nanofiber membrane support body is placed on the top of the urea powder in the crucible, the distance between the aluminum foil and the upper part of the urea powder is 5mm, and the porcelain boat is placed on the upper part of the urea powderSealing the ceramic crucible device with aluminum foil, placing into a tube furnace, and heating at 2 deg.C for min under nitrogen atmosphere-1The temperature rise rate is increased to 550 ℃ and the temperature is kept for 2h, and at high temperature, urea molecules at the bottom of the crucible can be rapidly diffused to [ TiO ] through the aluminum foil with holes2/C]//[Bi2WO6/C]The Janus nano-fiber surface and the urea molecules in the porcelain boat can also diffuse to the TiO from the top2/C]//[Bi2WO6/C]The co-diffusion of the upper part and the lower part on the surface of the Janus nano-fiber leads the g-C3N4Uniformly grow on [ TiO ]2/C]//[Bi2WO6/C]Janus nano fiber surface to obtain g-C3N4Nanosheet-modified [ TiO2/C]//[Bi2WO6/C]The Janus nanofiber heterojunction photocatalyst has a membrane area of 1 x 1cm2From highly dispersed g-C3N4Nanosheet modified in [ TiO ]2/C]//[Bi2WO6/C]The Janus nanofiber surface is formed, the diameter of a single nanofiber in the Janus nanofiber is 370 +/-4 nm, and g-C is obtained under the irradiation of simulated sunlight3N4Nanosheet-modified [ TiO2/C]//[Bi2WO6/C]The hydrogen production rate of the Janus nanofiber heterojunction photocatalyst for decomposing water is 17.48 mmol.h-1·g-1After the simulated sunlight irradiates for 100 minutes, the degradation rate of the methylene blue is 99.2 percent, and the double-function characteristics of photocatalytic hydrogen production and organic dye methylene blue degradation are good, so that the purpose of the invention is realized.
Technical Field
The invention relates to the technical field of nano material preparation, in particular to a Janus nanofiber heterojunction photocatalyst modified by carbon nitride nanosheets.
Background
Energy shortage and environmental pollution are two major problems facing the human society at present, and have attracted high attention of people. The photocatalytic technology is expected to solve the two problems, and becomes one of the leading-edge hot research subjects of material science. The hydrogen energy is an important clean energy, the hydrogen production by decomposing water by utilizing the photocatalysis technology is one of important ways for obtaining the hydrogen energy, and the dilemma of energy shortage can be well solved. The photocatalytic decomposition of pollutants in the environment is one of the important ways to protect the environment and solve the environmental pollution. Designing and constructing a photocatalyst with a novel and efficient structure is the key of development and application of a photocatalytic technology, and becomes a leading-edge hotspot research direction in the field of photocatalytic technologies.
Janus material refers to a material with two chemical compositions or one chemical composition but different structure and a definite partition structure in the same system, so that the material has dual properties such as hydrophilicity/hydrophobicity, luminescence/conductivity and the like, and is one of leading and hot research directions in the field of material science. The Janus nanofiber refers to two nanofibers with definite regional structures and chemical compositions in the same nanofiber, for example, one side of the nanofiber is a semiconductor TiO with a larger forbidden band width2The other side of the nano-fiber is a semiconductor Bi with smaller forbidden band width2WO6The two strands of the/C composite fiber are joined side by side to form the [ TiO ]2/C]//[Bi2WO6/C]Janus nanofibers, which would have particular properties and applications.
U.S. Pat. No. 1975504 discloses a solution for electrospinning, also called electrospinning, which is a continuous process for preparing micro-nano structures with macroscopic lengthAn effective method of fiber was first proposed by Formhals in 1934. The method is mainly used for preparing polymer nano fibers and is characterized in that charged polymer solution or melt is pulled by electrostatic force in an electrostatic field and sprayed out by a nozzle to be thrown to an opposite receiving screen so as to realize wire drawing, and then solvent is evaporated at normal temperature or the melt is cooled to normal temperature and solidified to obtain the micro-nano fibers. S. Yang et al have used electrospinning technology to prepare MoSe for organic pollutant degradation2One-dimensional nanofiber photocatalyst of/C [ J.colloid Interface Sci ], 2018,518,1-10](ii) a Q.Na et al prepared MoS by electrospinning2/CdS-TiO2Nanofiber hydrogen production photocatalyst [ appl.Catal., B: environ, 2017,202,374-](ii) a X.J.Zhou et al prepared graphite phase carbon nitride g-C by electrospinning3N4Nanosheet/TiO2Nanofiber photocatalysts [ J.Hazard.Mater.,2018,344, 113-122-](ii) a Preparation of TiO by P.F.xu et al by electrospinning2/Bi2WO6/C nanofiber photocatalyst Environ.Sci.,2018,5,327-337](ii) a Dong-Xiang-Ting et al prepared Eu (BA) by parallel electrospinning3phen/PVP// PANI/PVP photoelectric dual-function two parallel nanometer fiber bundles [ national invention patent, application number: 201210407369.5](ii) a Li et al prepared SnO with ethanol sensing performance by parallel electrospinning technology2//TiO2Janus nanofibers [ mater. Lett.,2020,262,127070]. At present, the technology of combining the electrospinning technology and the urea gasification gas-solid phase reaction for preparing the g-C is not seen3N4Nanosheet-modified [ TiO2/C]//[Bi2WO6/C]Related reports of Janus nanofiber heterojunction photocatalysts.
When the nano material is prepared by the electrospinning technology, the types of raw materials, the molecular weight of the high-molecular template agent, the composition of the spinning solution, the parameters of the spinning process and the structure of the spinning nozzle have important influences on the appearance and the size of a final product. The invention first prepares two spinning solutions, namely TiO2The mixed solution of nanocrystalline/polyacrylonitrile PAN/N, N-dimethylformamide DMF is a spinning solution, (NH)4)10W12O41/Bi(NO3)3The mixed solution of citric acid/PAN/DMF is another spinning solution, and the control of the viscosity of the spinning solution is important; two spinning solutions are filled into two syringes, a positive high-voltage direct-current power supply, a negative high-voltage direct-current power supply and an aluminum rotary drum are used as a receiving device, and the [ TiO ] is prepared by using a conjugate electrospinning technology under the optimal spinning process conditions2/PAN]//[(NH4)10W12O41/Bi(NO3)3Citric acid/PAN]Janus nano fiber film, then heat treatment is carried out to obtain [ TiO ]2/C]//[Bi2WO6/C]A Janus nanofiber membrane; growing carbon nitride g-C on the surface of the Janus nanofiber by gas-solid phase reaction through urea gasification3N4Nanosheets to give g-C3N4Nanosheet-modified [ TiO2/C]//[Bi2WO6/C]A Janus nanofiber heterojunction photocatalyst; the catalyst has the double functions of photocatalytic water splitting hydrogen production and photodegradation of methylene blue, and has important application prospect.
Disclosure of Invention
In the background technology, the electrostatic spinning technology is adopted to prepare the inorganic semiconductor one-dimensional nanofiber photocatalyst, the inorganic semiconductor/C composite nanofiber photocatalyst and the g-C3N4Nanosheet/TiO2Nanofiber photocatalyst, SnO2//TiO2Janus nanofibers and Eu (BA)3phen/PVP// PANI/PVP photoelectric double-function two parallel nanometer fiber bundles. The starting materials, templating agent, solvent, and final desired product used are different from the process of the present invention. The invention adopts conjugated electrostatic spinning technology to prepare the TiO2/PAN]//[(NH4)10W12O41/Bi(NO3)3Citric acid/PAN]Janus nano fiber film, then heat treatment is carried out to obtain [ TiO ]2/C]//[Bi2WO6/C]The Janus nanofiber membrane is prepared by growing carbon nitride g-C on the surface of Janus nanofibers through gas-solid phase reaction by gasifying urea3N4Nanosheets to give g-C3N4Nanosheet-modified [ TiO2/C]//[Bi2WO6/C]Janus nanofiber heterojunction photocatalyst.
The invention is realized by firstly preparing two spinning solutions, namely TiO2Taking a mixed solution of nanocrystalline, polyacrylonitrile PAN and N, N-dimethylformamide DMF as a spinning solution, and adding (NH)4)10W12O41、Bi(NO3)3The mixed solution of citric acid, PAN and DMF is used as another spinning solution, and the control of the viscosity of the spinning solution is very important. Two spinning solutions are filled into two syringes, a positive high-voltage direct-current power supply, a negative high-voltage direct-current power supply and an aluminum rotary drum are used as a receiving device, and the [ TiO ] is prepared by using a conjugated electrospinning technology under the optimal spinning process conditions2/PAN]//[(NH4)10W12O41/Bi(NO3)3Citric acid/PAN]Janus nano fiber film, then heat treatment is carried out to obtain [ TiO ]2/C]//[Bi2WO6/C]A Janus nanofiber membrane; growing g-C on the surface of the Janus nanofiber by gas-solid phase reaction through urea gasification3N4Nanosheets to give g-C3N4Nanosheet-modified [ TiO2/C]//[Bi2WO6/C]Janus nanofiber heterojunction photocatalyst. The method comprises the following steps:
(1) preparing spinning solution
0.6g of TiO with a particle size of 25nm2Nanocrystalline, 2.0g PAN dispersed in 20.0g DMF, stirring continuously at 60 ℃ until a homogeneous dope, called dope A, is formed; 0.3042g of (NH)4)10W12O41And 0.5044g citric acid into distilled water, heating to evaporate to form viscous jelly, and sequentially adding 20.0g DMF and 1.1646g Bi (NO)3)3·5H2O and 2.0g PAN are stirred at 60 ℃ to form uniform spinning solution, namely spinning solution B;
(2) preparation of [ TiO ]2/PAN]//[(NH4)10W12O41/Bi(NO3)3Citric acid/PAN]Janus nanofiber membrane
Respectively transferring the spinning solution A and the spinning solution B into a plastic syringe with a stainless steel needle head, and adopting a positive high-voltage direct current and a negative high-voltage direct currentThe power supply and the receiving device are horizontally arranged cylindrical aluminum revolving drums with the length of 20cm and the diameter of 7cm, the rotating speed is 1200r/min, 8.5kV positive and negative voltage is applied, and the flow speed of the spinning solution is 0.8mL h-1The distance between the needle point and the rotary drum of the collecting device is 16cm, and conjugated electrospinning is carried out at room temperature to obtain the TiO2/PAN]//[(NH4)10W12O41/Bi(NO3)3Citric acid/PAN]A Janus nanofiber membrane;
(3) preparation of [ TiO ]2/C]//[Bi2WO6/C]Janus nanofiber membrane
To make g-C3N4Uniformly growing the TiO on the surface of the Janus nano-fiber in the gas-solid phase reaction process2/PAN]//[(NH4)10W12O41/Bi(NO3)3Citric acid/PAN]Janus nanofiber membrane was cut to a size of 1X 1cm2Placing the small blocks into a tube furnace, and then placing the small blocks in the air atmosphere at 1 ℃ for min-1The temperature rise rate of (2) is increased to 270 ℃ and the temperature is maintained for 1h, and then the temperature is increased to 2 ℃ per minute under the nitrogen atmosphere-1Heating to 800 deg.C, maintaining the temperature and carbonizing for 2h, and naturally cooling to room temperature to obtain [ TiO ]2/C]//[Bi2WO6/C]A Janus nanofiber membrane;
(4) preparation of g-C3N4Nanosheet-modified [ TiO2/C]//[Bi2WO6/C]Janus nanofiber heterojunction photocatalyst
Preparation of g-C by gas-solid phase reaction3N4Nanosheet-modified [ TiO2/C]//[Bi2WO6/C]Janus nanofiber heterojunction photocatalyst is prepared by placing a small porcelain crucible in a porcelain boat, uniformly dispersing urea powder with the mass of 2.5g at the bottom of the porcelain boat and the porcelain crucible, and taking a circular aluminum foil with holes as [ TiO ]2/C]//[Bi2WO6/C]The support body of Janus nanofiber membrane is placed on the top of urea powder in a crucible, the distance between aluminum foil and the upper part of the urea powder is 5mm, the ceramic boat and the ceramic crucible device are sealed by the aluminum foil, and then the ceramic boat and the ceramic crucible device are placed in a tube furnace and are heated for 2 ℃ min under the nitrogen atmosphere-1At a temperature rise rate ofKeeping the temperature at 550 ℃ for 2h, and rapidly diffusing urea molecules at the bottom of the crucible to the TiO through the aluminum foil with holes at high temperature2/C]//[Bi2WO6/C]The Janus nano-fiber surface and the urea molecules in the porcelain boat can also diffuse to the TiO from the top2/C]//[Bi2WO6/C]The co-diffusion of the upper part and the lower part on the surface of the Janus nano-fiber leads the g-C3N4Uniformly grow on [ TiO ]2/C]//[Bi2WO6/C]Janus nano fiber surface to obtain g-C3N4Nanosheet-modified [ TiO2/C]//[Bi2WO6/C]Janus nanofiber heterojunction photocatalyst.
g-C prepared in the above procedure3N4Nanosheet-modified [ TiO2/C]//[Bi2WO6/C]The membrane area of the Janus nanofiber heterojunction photocatalyst is 1 multiplied by 1cm2From highly dispersed g-C3N4Nanosheet modified in [ TiO ]2/C]//[Bi2WO6/C]The Janus nanofiber surface is formed, the diameter of a single nanofiber in the Janus nanofiber is 370 +/-4 nm, and g-C is obtained under the irradiation of simulated sunlight3N4Nanosheet-modified [ TiO2/C]//[Bi2WO6/C]The hydrogen production rate of the Janus nanofiber heterojunction photocatalyst for decomposing water is 17.48 mmol.h-1·g-1After the simulated sunlight irradiates for 100 minutes, the degradation rate of the methylene blue is 99.2 percent, and the double-function characteristics of photocatalytic hydrogen production and organic dye methylene blue degradation are good, so that the purpose of the invention is realized.
Drawings
FIG. 1 is g-C3N4An XRD spectrogram of the nano-sheet modified Janus nanofiber heterojunction photocatalyst;
FIG. 2 is g-C3N4SEM photograph of the nano-sheet modified Janus nano-fiber heterojunction photocatalyst;
FIG. 3 is g-C3N4The diameter distribution histogram of a single fiber in the nanosheet-modified Janus nanofiber heterojunction photocatalyst;
FIG. 4 is g-C3N4Nano meterEDS line analysis spectrogram of Janus nanofibers in the sheet-modified Janus nanofiber heterojunction photocatalyst is also taken as an abstract attached drawing;
FIG. 5 is g-C3N4The ultraviolet-visible absorption spectrogram of the nano-sheet modified Janus nanofiber heterojunction photocatalyst;
FIG. 6 is g-C3N4A nitrogen adsorption-desorption isotherm diagram of the nano-sheet modified Janus nanofiber heterojunction photocatalyst;
FIG. 7 is g-C3N4The Janus nanofiber heterojunction photocatalyst modified by the nanosheets has the water decomposition and hydrogen production performance under the irradiation of visible light;
FIG. 8 is g-C3N4The Janus nanofiber heterojunction photocatalyst modified by the nanosheets can decompose water to produce hydrogen under the irradiation of visible light, so that the hydrogen can be recycled and used stably;
FIG. 9 is g-C3N4The Janus nanofiber heterojunction photocatalyst modified by the nanosheets has the water decomposition and hydrogen production performance under the irradiation of simulated sunlight;
FIG. 10 is g-C3N4The Janus nanofiber heterojunction photocatalyst modified by the nanosheets has the methylene blue degradation performance under the irradiation of visible light;
FIG. 11 is g-C3N4The degrading methylene blue of the nano-sheet modified Janus nano-fiber heterojunction photocatalyst is stable in recycling under the irradiation of visible light;
FIG. 12 is g-C3N4The Janus nanofiber heterojunction photocatalyst modified by the nanosheets can degrade methylene blue under the irradiation of simulated sunlight;
FIG. 13 is g-C3N4The degradation methylene blue of the nano-sheet modified Janus nano-fiber heterojunction photocatalyst under the irradiation of simulated sunlight is stable in recycling.
Detailed Description
The TiO with the particle size of 25nm is selected by the invention2Nanocrystalline, N, N-dimethylformamide, polyacrylonitrile with a molecular weight of 150000, urea, bismuth nitrate pentahydrate, ammonium tungstate, citric acid and nitrogen are all commercially available analytical pure products;self-made in a deionized water laboratory; the glassware and equipment used are those commonly used in the laboratory.
Example (b): 0.6g of TiO with a particle size of 25nm2Nanocrystalline, 2.0g PAN dispersed in 20.0g DMF, stirring continuously at 60 ℃ until a homogeneous dope, called dope A, is formed; 0.3042g of (NH)4)10W12O41And 0.5044g citric acid into distilled water, heating to evaporate to form viscous jelly, and sequentially adding 20.0g DMF and 1.1646g Bi (NO)3)3·5H2O and 2.0g PAN are stirred at 60 ℃ to form uniform spinning solution, namely spinning solution B; respectively transferring the spinning solution A and the spinning solution B into a plastic injector with a stainless steel needle head, adopting a positive high-voltage direct-current power supply, a negative high-voltage direct-current power supply, horizontally placing a cylindrical aluminum rotary drum with the length of 20cm and the diameter of 7cm, rotating at 1200r/min, applying a positive voltage and a negative voltage of 8.5kV, and enabling the flow rate of the spinning solution to be 0.8mL h-1The distance between the needle point and the rotary drum of the collecting device is 16cm, and conjugated electrospinning is carried out at room temperature to obtain the TiO2/PAN]//[(NH4)10W12O41/Bi(NO3)3Citric acid/PAN]A Janus nanofiber membrane; to make g-C3N4Uniformly growing the TiO on the surface of the Janus nano-fiber in the gas-solid phase reaction process2/PAN]//[(NH4)10W12O41/Bi(NO3)3Citric acid/PAN]Janus nanofiber membrane was cut to a size of 1X 1cm2Placing the small blocks into a tube furnace, and then placing the small blocks in the air atmosphere at 1 ℃ for min-1The temperature rise rate of (2) is increased to 270 ℃ and the temperature is maintained for 1h, and then the temperature is increased to 2 ℃ per minute under the nitrogen atmosphere-1Heating to 800 deg.C, maintaining the temperature and carbonizing for 2h, and naturally cooling to room temperature to obtain [ TiO ]2/C]//[Bi2WO6/C]A Janus nanofiber membrane; preparation of g-C by gas-solid phase reaction3N4Nanosheet-modified [ TiO2/C]//[Bi2WO6/C]Janus nanofiber heterojunction photocatalyst is prepared by placing a small porcelain crucible in a porcelain boat, and flattening urea powder with mass of 2.5gUniformly dispersed at the bottom of porcelain boat and porcelain crucible, and a round aluminum foil with holes is used as [ TiO ]2/C]//[Bi2WO6/C]The support body of Janus nanofiber membrane is placed on the top of urea powder in a crucible, the distance between aluminum foil and the upper part of the urea powder is 5mm, the ceramic boat and the ceramic crucible device are sealed by the aluminum foil, and then the ceramic boat and the ceramic crucible device are placed in a tube furnace and are heated for 2 ℃ min under the nitrogen atmosphere-1The temperature rise rate is increased to 550 ℃ and the temperature is kept for 2h, and at high temperature, urea molecules at the bottom of the crucible can be rapidly diffused to [ TiO ] through the aluminum foil with holes2/C]//[Bi2WO6/C]The Janus nano-fiber surface and the urea molecules in the porcelain boat can also diffuse to the TiO from the top2/C]//[Bi2WO6/C]The co-diffusion of the upper part and the lower part on the surface of the Janus nano-fiber leads the g-C3N4Uniformly grow on [ TiO ]2/C]//[Bi2WO6/C]Janus nano fiber surface to obtain g-C3N4Nanosheet-modified [ TiO2/C]//[Bi2WO6/C]Janus nanofiber heterojunction photocatalyst. g-C3N4TiO containing anatase phase and rutile phase in nanosheet-modified Janus nanofiber heterojunction photocatalyst2、Bi2WO6And g-C3N4See FIG. 1; highly dispersed g-C3N4The nano thin sheet is decorated on the surface of the Janus nano fiber, and is shown in figure 2; g-C3N4The diameter of a single nanofiber in the Janus nanofiber in the nanosheet-modified Janus nanofiber heterojunction photocatalyst is 370 +/-4 nm, which is shown in FIG. 3; the distribution of Bi and Ti elements can reflect Bi respectively2WO6And TiO2Distribution of N and C represents g-C3N4The Bi element is distributed on one side of the Janus nano-fiber, the Ti element is distributed on the other side of the Janus nano-fiber, and the N and the C are distributed on two sides of the Janus nano-fiber, which is similar to that of the g-C3N4The structure of the nano-sheet modified Janus nanofiber heterojunction photocatalyst is consistent, and is shown in FIG. 4; g-C3N4The nano-sheet modified Janus nano-fiber heterojunction photocatalyst can absorb ultraviolet light and visible light, namelyFIG. 5 is a schematic view; g-C3N4The nano-sheet modified Janus nano-fiber heterojunction photocatalyst has typical adsorption behavior, has an IV-type adsorption isotherm and a specific surface area of 39.48m2·g-1The average pore diameter is 30.2nm, as shown in FIG. 6; g-C3N4The nano-sheet modified Janus nano-fiber heterojunction photocatalyst has hydrogen production performance under the irradiation of visible light, and the hydrogen production rate is 13.04 mmol.h-1·g-1See FIG. 7; g-C3N4The nano-sheet modified Janus nano-fiber heterojunction photocatalyst has stable hydrogen production performance under the irradiation of visible light, and still has good hydrogen production performance after 5-time circulation test, wherein the hydrogen production rate is 12.58 mmol.h-1·g-1See FIG. 8; g-C3N4The nano-sheet modified Janus nano-fiber heterojunction photocatalyst has better hydrogen production performance under the irradiation of simulated sunlight, and the hydrogen production rate is 17.48 mmol.h-1·g-1See FIG. 9; g-C3N4The Janus nanofiber heterojunction photocatalyst modified by the nanosheets has the capability of degrading methylene blue under the irradiation of visible light, and after the irradiation is carried out for 100 minutes, the degradation rate is 97.0%, which is shown in FIG. 10; g-C3N4The Janus nanofiber heterojunction photocatalyst modified by the nanosheets has stable methylene blue degradation performance under the irradiation of visible light, still has good degradation performance after 3 times of cycle tests, and the degradation rate is 94.7% after 100 minutes of irradiation, as shown in FIG. 11; g-C3N4The Janus nanofiber heterojunction photocatalyst modified by the nanosheets has better methylene blue degradation performance under the irradiation of simulated sunlight, and after the irradiation is carried out for 100 minutes, the degradation rate is 99.2%, which is shown in figure 12; g-C3N4The Janus nanofiber heterojunction photocatalyst modified by the nanosheets has stable methylene blue degradation performance under simulated sunlight irradiation, still has good degradation performance after 3 times of cycle test, and the degradation rate is 96.5% after irradiation for 100 minutes, as shown in FIG. 13; g-C prepared3N4The nanosheet-modified Janus nanofiber heterojunction photocatalyst has good photocatalytic hydrogen production and photocatalytic degradation organic propertyThe dye methylene blue has a bifunctional characteristic.
The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it should be understood that various changes and modifications can be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.