Disclosure of Invention
Based on the technical problems in the background art, the invention provides the bismuth-based composite photocatalyst and the synthesis method thereof, the synthesis method has the advantages of simple process, mild conditions and high yield, and the obtained composite photocatalyst has high photocatalytic activity and good stability.
The invention provides a synthesis method of a bismuth-based composite photocatalyst, which comprises the following steps: mixing bismuth nitrate, cetyl trimethyl ammonium bromide and a polyalcohol solvent, and uniformly stirring to form a reaction solution, wherein the molar ratio of the bismuth nitrate to the cetyl trimethyl ammonium bromide in the reaction solution is 1: 3-1: 6; and (3) reacting the reaction solution at 90-130 ℃ for 4-24h, and after the reaction is finished, cooling, carrying out solid-liquid separation, washing and drying to obtain the bismuth-based composite photocatalyst.
Preferably, the polyol solvent is one or more of ethylene glycol, glycerol, diethylene glycol and polyethylene glycol 400.
Preferably, the polyol solvent is ethylene glycol.
Preferably, the concentration of bismuth nitrate in the reaction solution is 0.02 to 0.08 mol/L.
Preferably, the molar ratio of bismuth nitrate to cetyltrimethylammonium bromide in the reaction solution is 1: 3.
preferably, the synthesis method of the bismuth-based composite photocatalyst comprises the following steps: adding 0.0012mol of bismuth nitrate and 0.0036-0.0072mol of hexadecyl trimethyl ammonium bromide into 15-60ml of ethylene glycol, and uniformly stirring to form a reaction solution; and (3) placing the reaction solution in a round-bottom flask, reacting for 4-24h at 90-130 ℃, naturally cooling after the reaction is finished, and washing and drying the obtained solid after centrifugal separation to obtain the bismuth-based composite photocatalyst.
Preferably, the synthesis method of the bismuth-based composite photocatalyst comprises the following steps: adding 0.0012mol of bismuth nitrate and 0.0036-0.0072mol of hexadecyl trimethyl ammonium bromide into 45ml of ethylene glycol, and uniformly stirring to form a reaction solution; and (3) placing the reaction solution in a round-bottom flask, reacting for 7 hours at 110 ℃, naturally cooling after the reaction is finished, and washing and drying the obtained solid after centrifugal separation to obtain the bismuth-based composite photocatalyst.
The invention also provides a bismuth-based composite photocatalyst, which is prepared by adopting the synthesis method of the bismuth-based composite photocatalyst.
In the synthesis method of the bismuth-based composite photocatalyst, bismuth nitrate and cetyl trimethyl ammonium bromide are used as raw materials, and the molar ratio of the bismuth nitrate to the cetyl trimethyl ammonium bromide is controlled to be 1: 3-1: 6, the temperature and the time of the reaction are adjusted simultaneously, and the bismuth-based composite photocatalyst is synthesized in one step and is BiOBr and [ Bi6O4(OH)4](NO3)6(H2O)4The composite material has simple process, mild condition, yield near 95%, high catalytic activity and high stability.
Detailed Description
The technical solution of the present invention will be described in detail below with reference to specific examples.
Example 1
The invention provides a synthesis method of a bismuth-based composite photocatalyst, which comprises the following steps: adding 0.0012mol of bismuth nitrate and 0.0036mol of hexadecyl trimethyl ammonium bromide into 45ml of ethylene glycol, and uniformly stirring to form a reaction solution; and (3) placing the reaction solution in a round-bottom flask, reacting for 7 hours at 110 ℃, naturally cooling to room temperature after the reaction is finished, centrifugally separating, washing the obtained solid with distilled water, and drying for 8 hours at 60 ℃ to obtain the bismuth-based composite photocatalyst.
Example 2
The invention provides a synthesis method of a bismuth-based composite photocatalyst, which comprises the following steps: adding 0.0012mol of bismuth nitrate and 0.0072mol of hexadecyl trimethyl ammonium bromide into 45ml of ethylene glycol, and stirring uniformly to form a reaction solution; and (3) placing the reaction solution in a round-bottom flask, reacting for 7 hours at 110 ℃, naturally cooling to room temperature after the reaction is finished, centrifugally separating, washing the obtained solid with distilled water, and drying for 8 hours at 60 ℃ to obtain the bismuth-based composite photocatalyst.
Comparative example 1
A synthetic method of a BiOBr photocatalyst comprises the following steps: adding 0.0012mol of bismuth nitrate and 0.0012mol of hexadecyl trimethyl ammonium bromide into 45ml of ethylene glycol, and stirring uniformly to form a reaction solution; and (3) placing the reaction solution into a round-bottom flask, reacting for 7h at 110 ℃, naturally cooling to room temperature after the reaction is finished, centrifugally separating, washing the obtained solid with distilled water, and drying for 8h at 60 ℃ to obtain the BiOBr photocatalyst.
Example 3
The invention provides a synthesis method of a bismuth-based composite photocatalyst, which comprises the following steps: adding 0.0012mol of bismuth nitrate and 0.0036mol of hexadecyl trimethyl ammonium bromide into 30ml of ethylene glycol, and stirring uniformly to form a reaction solution; and (3) placing the reaction solution in a round-bottom flask, reacting at 90 ℃ for 24 hours, naturally cooling to room temperature after the reaction is finished, centrifugally separating, washing the obtained solid with distilled water, and drying at 50 ℃ for 11 hours to obtain the bismuth-based composite photocatalyst.
Example 4
The invention provides a synthesis method of a bismuth-based composite photocatalyst, which comprises the following steps: adding 0.0012mol of bismuth nitrate and 0.0072mol of hexadecyl trimethyl ammonium bromide into 60ml of ethylene glycol, and stirring uniformly to form a reaction solution; and (3) placing the reaction solution in a round-bottom flask, reacting for 4 hours at 130 ℃, naturally cooling to room temperature after the reaction is finished, centrifugally separating, washing the obtained solid with distilled water, and drying for 6 hours at 80 ℃ to obtain the bismuth-based composite photocatalyst.
Example 5
The invention provides a synthesis method of a bismuth-based composite photocatalyst, which comprises the following steps: adding 0.0012mol of bismuth nitrate and 0.0048mol of hexadecyl trimethyl ammonium bromide into 15ml of ethylene glycol, and stirring uniformly to form a reaction solution; and (3) placing the reaction solution in a round-bottom flask, reacting for 10 hours at 100 ℃, naturally cooling to room temperature after the reaction is finished, centrifugally separating, washing the obtained solid with distilled water, and drying for 7 hours at 70 ℃ to obtain the bismuth-based composite photocatalyst.
Example 6
The invention provides a synthesis method of a bismuth-based composite photocatalyst, which comprises the following steps: adding 0.002mol of bismuth nitrate and 0.01mol of hexadecyl trimethyl ammonium bromide into a solvent consisting of 25ml of ethylene glycol and 30ml of polyethylene glycol 400, and uniformly stirring to form a reaction solution; and (3) placing the reaction solution in a round-bottom flask, reacting for 17 hours at the temperature of 98 ℃, naturally cooling to room temperature after the reaction is finished, centrifugally separating, washing the obtained solid with distilled water, and drying for 7 hours at the temperature of 65 ℃ to obtain the bismuth-based composite photocatalyst.
Example 7
The invention provides a synthesis method of a bismuth-based composite photocatalyst, which comprises the following steps: adding 0.002mol of bismuth nitrate and 0.007mol of hexadecyl trimethyl ammonium bromide into 80ml of glycerol, and stirring uniformly to form a reaction solution; and (3) placing the reaction solution in a round-bottom flask, reacting for 20h at 112 ℃, naturally cooling to room temperature after the reaction is finished, centrifugally separating, washing the obtained solid with distilled water, and drying for 8h at 60 ℃ to obtain the bismuth-based composite photocatalyst.
The invention also provides a bismuth-based composite photocatalyst which is prepared by adopting the synthesis method of the bismuth-based composite photocatalyst and is BiOBr and [ Bi6O4(OH)4](NO3)6(H2O)4The composite material with the multilevel structure is formed.
Example 8
The invention provides a synthesis method of a bismuth-based composite photocatalyst, which comprises the following steps: adding 0.003mol of bismuth nitrate and 0.009mol of hexadecyl trimethyl ammonium bromide into a round-bottom flask, then adding 20ml of ethylene glycol and 60ml of diethylene glycol, uniformly stirring, reacting at 105 ℃ for 9 hours, naturally cooling to room temperature after the reaction is finished, filtering, washing the obtained filter cake with distilled water, and drying at 60 ℃ for 8 hours to obtain the bismuth-based composite photocatalyst.
The invention also provides a bismuth-based composite photocatalyst, which is prepared by adopting the synthesis method of the bismuth-based composite photocatalyst.
Example 9
The invention provides a synthesis method of a bismuth-based composite photocatalyst, which comprises the following steps: mixing bismuth nitrate, cetyl trimethyl ammonium bromide and ethylene glycol, and uniformly stirring to form a reaction solution, wherein the concentration of the bismuth nitrate is 0.08mol/L, and the molar ratio of the bismuth nitrate to the cetyl trimethyl ammonium bromide is 1: 3; and (3) reacting the reaction solution at 130 ℃ for 4 hours, and after the reaction is finished, cooling, carrying out solid-liquid separation, washing and drying to obtain the bismuth-based composite photocatalyst.
The invention also provides a bismuth-based composite photocatalyst, which is prepared by adopting the synthesis method of the bismuth-based composite photocatalyst.
Example 10
The invention provides a synthesis method of a bismuth-based composite photocatalyst, which comprises the following steps: mixing bismuth nitrate, cetyl trimethyl ammonium bromide and a polyol solvent, and uniformly stirring to form a reaction solution, wherein the concentration of bismuth nitrate in the reaction solution is 0.02mol/L, and the molar ratio of bismuth nitrate to cetyl trimethyl ammonium bromide is 1: 6, the polyalcohol solvent is a mixture of glycerol and diethylene glycol; and (3) reacting the reaction solution at 90 ℃ for 24 hours, and after the reaction is finished, cooling, carrying out solid-liquid separation, washing and drying to obtain the bismuth-based composite photocatalyst.
The invention also provides a bismuth-based composite photocatalyst, which is prepared by adopting the synthesis method of the bismuth-based composite photocatalyst.
Example 11
The invention provides a synthesis method of a bismuth-based composite photocatalyst, which comprises the following steps: mixing bismuth nitrate, cetyl trimethyl ammonium bromide and a polyalcohol solvent, and uniformly stirring to form a reaction solution, wherein the concentration of bismuth nitrate in the reaction solution is 0.06mol/L, and the molar ratio of bismuth nitrate to cetyl trimethyl ammonium bromide is 1: 5, the polyalcohol solvent is a mixture of glycol and polyethylene glycol 400; and (3) reacting the reaction solution at 115 ℃ for 18h, and after the reaction is finished, cooling, carrying out solid-liquid separation, washing and drying to obtain the bismuth-based composite photocatalyst.
The invention also provides a bismuth-based composite photocatalyst, which is prepared by adopting the synthesis method of the bismuth-based composite photocatalyst.
FIG. 1 shows X-ray diffraction patterns and BiOBr and [ Bi ] of photocatalysts prepared in examples 1 and 2 of the present invention and comparative example 16O4(OH)4](NO3)6(H2O)4XRD standard card of (1), wherein [ Bi6O4(OH)4](NO3)6(H2O)4The XRD standard card of (1) is JCPDS No.84-2189, a is the X-ray diffraction pattern of the photocatalyst obtained in example 2, b is the X-ray diffraction pattern of the photocatalyst obtained in example 1, c is the X-ray diffraction pattern of the photocatalyst obtained in comparative example 1, and the XRD standard card of BiOBr is JCPDS No.09-0393, wherein the characteristic peaks in JCPDS No.84-2189 are marked with # in a, b and c, and the characteristic peaks in JCPDS No.09-0393 are marked with # in a, b and c; as can be seen from fig. 1, in the preparation of the photocatalyst, when Bi: the molar ratio of Br is 1: at 1 (i.e., a molar ratio of bismuth nitrate to cetyltrimethylammonium bromide of 1: 1), the resulting sample was phase-pure BiOBr (JCPDS No. 09-0393); when the Bi is increased: the molar ratio of Br is 1: at 3 (i.e., a molar ratio of bismuth nitrate to cetyltrimethylammonium bromide of 1: 3), the XRD diffraction pattern of the resulting product exhibited [ Bi6O4(OH)4](NO3)6(H2O)4A phase (JCPDS No.84-2189), namely a bismuth-based composite photocatalyst [ Bi ] is formed6O4(OH)4](NO3)6(H2O)4-BiOBr; increasing Bi again: the molar ratio of Br is 1: when the molar ratio of the bismuth nitrate to the hexadecyl trimethyl ammonium bromide is 1: 6, the obtained product is still the bismuth-based composite photocatalyst [ Bi6O4(OH)4](NO3)6(H2O)4-BiOBr。
FIG. 2 is an XPS high resolution spectrum of Bi 4f in the bismuth-based composite photocatalyst synthesized in example 1 of the present invention; in FIG. 2, two peaks with binding energies of 158.97eV and 164.31eV correspond to Bi 4f7/2And Bi 4f5/2Thus, it is shown that the Bi element in the sample of the composite photocatalyst obtained in example 1 is Bi3+The form exists;
FIG. 3 is an XPS high resolution spectrum of O1 s in the bismuth-based composite photocatalyst synthesized in example 1 of the present invention; as can be seen from FIG. 3, the only XPS peak is at 531.9eV, indicating that the valence of the O element in the sample is-2;
FIG. 4 is an XPS high resolution spectrum of Br 3d in the bismuth-based composite photocatalyst synthesized in example 1 of the present invention; as can be seen from FIG. 4, it can be fitted with two peaks 68.01eV and 69.11eV, corresponding to Br 3d5/2And Br 3d3/2Thus, it was shown that Br is an element Br in the sample of the composite photocatalyst obtained in example 1-The form exists;
FIG. 5 is an XPS high resolution spectrum of N1 s in the bismuth-based composite photocatalyst synthesized in example 1 of the present invention; as can be seen from FIG. 5, the only peak is located at 402.08eV, which indicates that the valence of N element in the sample of the composite photocatalyst obtained in example 1 is +5, i.e., NO3 -Exists in the form of (1);
figure 6 is an SEM photograph of the bibbr photocatalyst synthesized in comparative example 1 of the present invention; as can be seen from fig. 6, the synthesized BiOBr photocatalyst is a multi-stage structure assembled by nanosheets;
FIG. 7 is an SEM photograph of the bismuth-based composite photocatalyst synthesized in example 1 of the present invention; as can be seen from fig. 7, the obtained product is still a multi-level structure assembled by the nanosheets, and many nanoparticles with smaller sizes appear on the surface of the assembled unit of the nanosheets;
figure 8 is a diffuse reflectance spectrum of a BiOBr photocatalyst synthesized in comparative example 1 of the present invention; as can be seen from fig. 8, the band gap of the obtained product BiOBr photocatalyst is about 2.97 eV;
FIG. 9 is a diffuse reflectance spectrum of the bismuth-based composite photocatalyst synthesized in example 1 of the present invention; as can be seen from FIG. 9, the band gap of the obtained composite photocatalyst product is about 2.89 eV;
FIG. 10 is a diffuse reflectance spectrum of the bismuth-based composite photocatalyst synthesized in example 2 of the present invention; as can be seen from FIG. 10, the band gap of the obtained composite photocatalyst product is about 2.84 eV;
fig. 11 is a degradation efficiency curve of rhodamine B aqueous solution degraded under ultraviolet-visible light irradiation under the conditions of using the photocatalysts synthesized in example 1, example 2 and comparative example 1 as catalysts and no catalyst, and it can be known from fig. 11 that the bismuth-based composite photocatalyst obtained in example 1 exhibits the best photocatalytic activity, the degradation efficiency of the rhodamine B aqueous solution with the concentration of 40mg/L is as high as 96.2% after 12 minutes of light irradiation, which is far greater than the degradation efficiency under the photocatalytic conditions of other two photocatalytic samples and no catalyst.
FIG. 12 is a graph showing the photocatalytic cycle efficiency of the bismuth-based composite photocatalyst synthesized in example 1 of the present invention; as can be seen from fig. 12, the obtained product exhibited excellent photocatalytic stability, and no significant decay of photocatalytic activity occurred after four cycles.
FIG. 13 is a graph showing photocurrent curves of photocatalysts obtained in examples 1 and 2 according to the present invention and comparative example 1; as can be seen from fig. 13, the composite photocatalyst obtained in example 1 has the highest photocurrent density, which indicates that it has better photo-generated charge separation efficiency, and thus exhibits the best photocatalytic activity.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.