Preparation method and application of rare earth ion doped modified upconversion photocatalyst
By modifying the Bi3Ti2O8F photocatalyst with rare earth ion doping, the problems of low spectral utilization and high recombination rate of photogenerated carriers were solved, realizing the conversion of low-energy near-infrared light to high-energy ultraviolet or visible light, improving photocatalytic efficiency, and making it suitable for the degradation of organic dyes, endocrine secretions, antibiotics and heavy metal pollutants.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-28
- Publication Date
- 2026-04-07
AI Technical Summary
The Bi3Ti2O8F photocatalyst suffers from low spectral utilization and high recombination rate of photogenerated carriers, which limits its practical application.
Rare earth ion-doped upconversion photocatalysts are prepared by doping Er3+, Tm3+, or Ho3+ as activating ions and Yb3+ or Nd3+ as sensitizers. These photocatalysts are synthesized using solid-state methods or hydrothermal/solvothermal methods to convert low-energy near-infrared light into high-energy ultraviolet or visible light, thereby improving photocatalytic efficiency.
It significantly improves the spectral response range of the photocatalyst and the efficiency of photocatalytic degradation of pollutants. The material preparation method is simple and inexpensive, making it suitable for large-scale production.
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Figure CN121797366A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of photocatalyst technology, specifically to a method for preparing and applying a rare-earth ion-doped modified upconversion photocatalyst. Background Technology
[0002] Currently, the energy crisis and environmental pollution are becoming serious threats to human sustainable development. Semiconductor-based photocatalysis technology is considered an effective strategy to solve this problem because it can not only collect sunlight to decompose pollutants, but also decompose water to produce hydrogen by absorbing sunlight. Finding high-performance photocatalysts has become a common goal pursued by many scientists.
[0003] Among numerous photocatalyst materials, bismuth-based photocatalysts have attracted widespread attention due to their tunable band gap and unique layered structure, such as Bi3Ti2O8F, which consists of positively charged [Bi2O2]. 2+ Layers and negatively charged perovskite [BiTi2O6F] 2- The layered composition, with alternating layers of positive and negative atoms, facilitates the built-in electric field and accelerates carrier separation. Furthermore, the relatively negative conduction band position of Bi3Ti2O8F indicates its good reducing ability, which helps generate more active free radicals and thus promotes photocatalytic efficiency. However, Bi3Ti2O8F still suffers from low spectral utilization and high recombination rate of photogenerated carriers, severely limiting its practical applications.
[0004] Rare-earth-doped upconversion materials are considered an important way to broaden the spectral response range of photocatalysts due to their unique ability to convert near-infrared light into visible light. 3+ Tm 3+ Or Ho 3+ Due to their suitable energy level distribution and long intermediate state lifetimes, Yb is widely used as an activating ion for upconversion luminescence; 3+ and Nd 3+ Because it can transfer energy with the activator to improve its upconversion efficiency, it is used as a co-doperfinder for sensitizers. Therefore, the preparation of upconversion photocatalysts by doping upconversion rare earth ions into the lattice of monomeric Bi3Ti2O8F photocatalysts to achieve efficient degradation of pollutants has good research significance and value.
[0005] Therefore, in order to solve the above problems, this paper proposes a method for preparing rare earth ion-doped modified upconversion photocatalysts and their application. Summary of the Invention
[0006] The primary objective of this invention is to prepare a rare-earth ion-doped modified upconversion photocatalyst that can convert low-energy near-infrared light into high-energy ultraviolet or visible light, thereby indirectly utilizing near-infrared light to improve photocatalytic efficiency.
[0007] To achieve the above-mentioned technical effects, the present invention is implemented through the following technical solution: a rare earth ion-doped modified upconversion photocatalyst, characterized in that its chemical formula is Bi. 3-0.03(x+y) Ti2O8F:x%M 3+ ,y%N 3+ Where 2≤x≤20; 1≤y≤4; M includes Yb 3+ or Nd 3+ The N includes Er 3+ or Tm 3+ Or Ho 3+ .
[0008] The second objective of this invention is to provide a method for preparing rare earth ion-doped modified upconversion photocatalysts, characterized in that the catalyst is synthesized by a solid-state method or by a hydrothermal or solvothermal method.
[0009] Furthermore, the solid-state synthesis includes the following steps:
[0010] S1.1: Weigh out Bi2O3 and NH4F in a molar ratio of 0.5 to 1:1; then place Bi2O3 and NH4F in an agate mortar, add an appropriate amount of alcohol and grind thoroughly until dry; put the obtained powder into a corundum crucible and place it in a muffle furnace, sinter at 200 to 500°C for 4 to 24 hours to obtain the precursor BiOF;
[0011] S1.2: Place the precursor BiOF in an agate mortar, add TiO2, activator and sensitizer, add an appropriate amount of alcohol and grind thoroughly until dry; put the obtained powder into a corundum crucible and place it in a muffle furnace, sinter at 200-500℃ for 4-24h to obtain the rare earth ion doped modified upconversion photocatalyst.
[0012] Furthermore, the hydrothermal or solvothermal synthesis includes the following steps:
[0013] S2.1: Weigh out bismuth source, fluorine source, and titanium source in a molar ratio of 1-5:1:2-10; then dissolve the bismuth source and fluorine source in water or mannitol solution and stir until homogeneous to obtain a bismuth-fluorine mixture; simultaneously dissolve the titanium source in water or mannitol solution and stir until homogeneous to obtain a titanium source mixture; then add the bismuth-fluorine mixture to the titanium source mixture and adjust the pH of the solution to 8-12 to obtain the initial solution;
[0014] S2.2: Add activator and sensitizer to the initial solution, stir evenly, transfer the solution to a polytetrafluoroethylene liner and place it in an oven at 160-250℃ for 4-24 hours for reaction. After the reaction is completed, wash and dry to obtain the rare earth ion doped modified upconversion photocatalyst.
[0015] Furthermore, in S1.2, the molar ratio of the added precursor BiOF to TiO2 is 0.5 to 1:1; the molar ratio of the added activator, precursor BiOF and sensitizer is 0.5 to 2:100:1 to 10.
[0016] Furthermore, in S1.2 and S2.2, the activator is Er 3+ or Tm 3+ Or Ho 3+ The sensitizer is Yb 3+ or Nd 3+ .
[0017] Furthermore, in S2.1, the bismuth source is one or more of bismuth pentahydrate, bismuth carbonate, bismuth phosphate, and bismuth sulfate; the fluorine source is one or more of potassium fluoride, sodium fluoride, and ammonium fluoride; and the titanium source is one or more of titanium dioxide, titanium tetrachloride, and tetrabutyl titanate.
[0018] Furthermore, in S2.2, the molar ratio of the added activator, bismuth source, and sensitizer is 0.5–2:100:1–10.
[0019] A third objective of this invention is to provide an application of a rare-earth ion-doped modified upconversion photocatalyst, characterized in that the catalyst acts as a photocatalyst in the degradation of organic dyes, endocrine substances, antibiotics, and heavy metal pollutants.
[0020] The beneficial effects of this invention are:
[0021] The rare-earth ion-doped modified upconversion photocatalyst prepared in this invention can convert low-energy near-infrared light into high-energy ultraviolet or visible light, which is then indirectly absorbed and utilized by the catalyst in the photocatalytic process, thereby improving photocatalytic efficiency. The preparation method of the material in this invention is simple and inexpensive, suitable for large-scale production, and has promising industrial and market applications. Attached Figure Description
[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0023] Figure 1 The XRD pattern of the rare earth ion-doped modified upconversion photocatalyst prepared in this invention.
[0024] Figure 2 The absorption spectrum of the rare earth ion-doped modified upconversion photocatalyst prepared in this invention is shown.
[0025] Figure 3 The image shows the upconversion emission spectrum of the rare-earth ion-doped modified upconversion photocatalyst prepared in this invention.
[0026] Figure 4 This is a full-spectrum catalytic degradation diagram of the rare earth ion-doped modified upconversion photocatalyst prepared in this invention.
[0027] Figure 5 This is a flowchart illustrating the solid-state synthesis of rare-earth ion-doped modified upconversion photocatalysts according to the present invention.
[0028] Figure 6 This is a flowchart of the invention for synthesizing rare earth ion-doped modified upconversion photocatalysts using hydrothermal or solvothermal methods. Detailed Implementation
[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0030] Example 1
[0031] This embodiment provides a chemical formula of Bi. 2.67 Ti2O8F:10%Yb 3+ 1% Er 3+ A rare-earth ion-doped modified upconversion photocatalyst is synthesized by a solid-state method, and the preparation method is as follows:
[0032] S1. Weigh out Bi2O3 and NH4F in a molar ratio of 0.5 to 1:1, place them in an agate mortar, add an appropriate amount of alcohol, and grind them thoroughly until dry. Then, put the resulting powder into a corundum crucible and place it in a muffle furnace, and sinter it at 200 to 500°C for 4 to 24 hours to obtain the precursor BiOF.
[0033] S2, according to Bi 3+ Ti 4+ Er 3+ Yb 3+ The precursors BiOF, TiO2, Er2O3, and Yb2O3 obtained in S1 were weighed in a molar ratio of 2.67:2:0.03:0.3. BiOF, TiO2, Er2O3, and Yb2O3 were mixed and a suitable amount of alcohol was added. The mixture was then thoroughly ground until dry to obtain a powder. The powder was placed in an alumina crucible and then sintered at 400–800℃ for 4–24 hours to obtain the product with the chemical formula Bi. 2.67Ti2O8F:10%Yb 3+ 1% Er 3+ Rare earth ion-doped modified upconversion photocatalyst.
[0034] Example 2:
[0035] This embodiment provides a chemical formula of Bi. 2.67 Ti2O8F:10%Yb 3+ 1% Tm 3+ A rare-earth ion-doped modified upconversion photocatalyst is synthesized by a solid-state method, and the preparation method is as follows:
[0036] S1. Weigh out Bi2O3 and NH4F in a molar ratio of 0.5 to 1:1, place them in an agate mortar, add an appropriate amount of alcohol, and grind them thoroughly until dry. Place the resulting powder in a corundum crucible and place it in a muffle furnace, and sinter it at 200 to 500°C for 4 to 24 hours to obtain the precursor BiOF.
[0037] S2, according to Bi 3+ Ti 4+ Tm3 + Yb 3+ The precursors BiOF, TiO2, Tm2O3, and Yb2O3 obtained in S1 were weighed in a molar ratio of 2.67:2:0.03:0.3. BiOF, TiO2, Tm2O3, and Yb2O3 were mixed and a suitable amount of alcohol was added. The mixture was then thoroughly ground until dry to obtain a powder. This powder was placed in an alumina crucible and then sintered in a muffle furnace at 400–800℃ for 4–24 hours to obtain the product with the chemical formula Bi. 2.67 Ti2O8F:10%Yb 3+ 1% Tm 3+ Rare earth ion-doped modified upconversion photocatalyst.
[0038] Example 3:
[0039] This embodiment provides a chemical formula of Bi. 2.67 Ti2O8F:10%Yb 3+ 1% Ho 3+ A rare-earth ion-doped modified upconversion photocatalyst is synthesized by a solid-state method, and the preparation method is as follows:
[0040] Bi₂O₃ and NH₄F were weighed out in a molar ratio of 0.5 to 1:1, and placed in an agate mortar. An appropriate amount of alcohol was added, and the mixture was ground thoroughly until dry. The resulting powder was placed in a corundum crucible and then placed in a muffle furnace. The powder was sintered at 200–500 °C for 4–24 h to obtain the precursor BiOF.
[0041] S2, according to Bi 3+ Ti 4+ Er 3+ Yb 3+ The precursors BiOF, TiO2, Ho2O3, and Yb2O3 obtained in S1 were weighed in a molar ratio of 2.67:2:0.03:0.3. BiOF, TiO2, Ho2O3, and Yb2O3 were mixed and a suitable amount of alcohol was added. The mixture was then thoroughly ground until dry to obtain a powder. This powder was placed in an alumina crucible and then sintered in a muffle furnace at 400–800℃ for 4–24 hours to obtain the precursor with the chemical formula Bi. 2.67 Ti2O8F:10%Yb 3+ 1% Ho 3+ Rare earth ion-doped modified upconversion photocatalyst.
[0042] Example 4:
[0043] This embodiment provides a chemical formula of Bi. 2.67 Ti2O8F:10% Nd 3+ 1% Er 3+ A rare-earth ion-doped modified upconversion photocatalyst is synthesized by hydrothermal or solvothermal methods, and the preparation method is as follows:
[0044] S1. Take a bismuth source, a fluorine source, and a titanium source in a molar ratio of 1–5:1:2–10; then dissolve the bismuth source and the fluorine source in water or mannitol solution and stir until homogeneous to obtain a bismuth-fluorine mixture; simultaneously dissolve the titanium source in water or mannitol solution and stir until homogeneous to obtain a titanium source mixture; then add the bismuth-fluorine mixture to the titanium source mixture and adjust the pH of the solution to 8–12 to obtain the initial solution;
[0045] S2. Weigh a certain proportion of Er(NO3)3, Nd(NO3)3, and the above initial solution according to the molar ratio of activator, sensitizer, and bismuth source of 0.5–2:1–10:100. Add Er(NO3)3 and Nd(NO3)3 to the initial solution, stir evenly, and then put the solution into a polytetrafluoroethylene liner and place it in an oven. React at 160–250℃ for 4–24 hours to obtain Bi. 2.67 Ti2O8F:10% Nd 3+ 1% Er 3+ Rare earth ion-doped modified upconversion photocatalyst.
[0046] Example 5:
[0047] This embodiment provides a chemical formula of Bi. 2.67 Ti2O8F:10% Nd 3+ 1% Tm 3+A rare-earth ion-doped modified upconversion photocatalyst is synthesized by hydrothermal or solvothermal methods, and the preparation method is as follows:
[0048] S1. Take a bismuth source, a fluorine source, and a titanium source in a molar ratio of 1–5:1:2–10; then dissolve the bismuth source and the fluorine source in water or mannitol solution and stir until homogeneous to obtain a bismuth-fluorine mixture; simultaneously dissolve the titanium source in water or mannitol solution and stir until homogeneous to obtain a titanium source mixture; then add the bismuth-fluorine mixture to the titanium source mixture and adjust the pH of the solution to 8–12 to obtain the initial solution;
[0049] S2. Weigh out a certain proportion of Tm(NO3)3, Nd(NO3)3, and the above initial solution according to the molar ratio of activator, sensitizer, and bismuth source of 0.5–2:1–10:100. Add Er(NO3)3 and Nd(NO3)3 to the initial solution, stir evenly, and then put the solution into a polytetrafluoroethylene liner and place it in an oven at 160–250℃ for 4–24 hours to obtain Bi. 2.67 Ti2O8F:10% Nd 3+ 1% Tm 3+ Rare earth ion-doped modified upconversion photocatalyst.
[0050] Example 6:
[0051] This embodiment provides a chemical formula of Bi. 2.67 Ti2O8F:10% Nd 3+ 1% Ho 3+ A rare-earth ion-doped modified upconversion photocatalyst is synthesized by hydrothermal or solvothermal methods, and the preparation method is as follows:
[0052] S1. Take a bismuth source, a fluorine source, and a titanium source in a molar ratio of 1–5:1:2–10; then dissolve the bismuth source and the fluorine source in water or mannitol solution and stir until homogeneous to obtain a bismuth-fluorine mixture; simultaneously dissolve the titanium source in water or mannitol solution and stir until homogeneous to obtain a titanium source mixture; then add the bismuth-fluorine mixture to the titanium source mixture and adjust the pH of the solution to 8–12 to obtain the initial solution;
[0053] S2. Weigh out a certain proportion of Ho(NO3)3 and Nd(NO3)3 and the above initial solution according to the molar ratio of activator, sensitizer and bismuth source of 0.5-2:1-10:100. Add Ho(NO3)3 and Nd(NO3)3 to the initial solution, stir evenly, put the solution into a polytetrafluoroethylene liner and place it in an oven. React at 160-250℃ for 4-24 hours to obtain Bi 2.67 Ti2O8F:10% Nd 3+ 1% Ho 3+ Rare earth ion-doped modified upconversion photocatalyst.
[0054] Example 7:
[0055] Photocatalytic activity test
[0056] The photocatalytic activity of the samples for the degradation of organic dyes, antibiotics, and heavy metal ions was evaluated under a 300W xenon lamp (CEL-LAX500). A custom-made 100 mL quartz reactor was used. 10 mg of sample was added to the pollutant solution (40 mL, 10 mg / L), and the mixture was stirred in the dark for 0.5 h to ensure adsorption-desorption equilibrium. 4 mL of the reaction solution was periodically collected. The supernatant was analyzed using a UV-1800 spectrophotometer.
[0057] Depend on Figure 1 It can be seen that the Yb prepared in Example 1 3+ Er 3+ Doping modified Bi3Ti2O8F:Yb 3+ Er 3+ Both the upconversion photocatalyst and the pristine Bi3Ti2O8F correspond to the characteristic peaks of standard Bi3Ti2O8F, with no impurity peaks, indicating that Yb 3+ Er 3+ Doping successful.
[0058] Depend on Figure 2 It can be seen that the Yb prepared in Example 1 3+ Er 3+ Doping modified Bi3Ti2O8F:Yb 3+ Er 3+ The upconversion photocatalyst exhibits a stronger absorption response compared to the original Bi3Ti2O8F photocatalyst.
[0059] Depend on Figure 3 It can be seen that the Yb prepared in Example 1 3+ Er 3+ Doping modified Bi3Ti2O8F:Yb 3+ Er 3+ The upconversion photocatalyst significantly improves the upconversion emission intensity compared to the original Bi3Ti2O8F photocatalyst.
[0060] Depend on Figure 4 It can be seen that the Yb prepared in Example 1 3+ Er 3+ Doping modified Bi3Ti2O8F:Yb 3+ Er 3+ Compared with the original Bi3Ti2O8F photocatalyst, the upconversion photocatalyst significantly improves the efficiency of photocatalytic degradation of pollutants.
Claims
1. A rare-earth ion-doped modified upconversion photocatalyst, characterized in that, Its chemical formula is Bi 3-0.03(x+y) Ti2O8F:x%M 3+ ,y%N 3+ ; Wherein, 2≤x≤20; 1≤y≤4; and M includes Yb. 3+ or Nd 3+ The N includes Er 3+ or Tm 3+ Or Ho 3+ .
2. A method for preparing a rare-earth ion-doped modified upconversion photocatalyst, characterized in that, Synthesized by solid-state method or by hydrothermal or solvothermal method.
3. The method for preparing a rare-earth ion-doped modified upconversion photocatalyst according to claim 2, characterized in that, The solid-state synthesis includes the following steps: S1.1: Weigh Bi2O3 and NH4F separately at a molar ratio of 0.5 to 1:1; then place Bi2O3 and NH4F in an agate mortar, add an appropriate amount of alcohol and grind thoroughly until dry; put the obtained powder into a corundum crucible and place it in a muffle furnace, sinter at 200 to 500°C for 4 to 24 hours to obtain the precursor BiOF; S1.2: Place the precursor BiOF in an agate mortar, add TiO2, activator and sensitizer, add an appropriate amount of alcohol and grind thoroughly until dry; put the obtained powder into a corundum crucible and place it in a muffle furnace, sinter at 200-500℃ for 4-24h to obtain the rare earth ion doped modified upconversion photocatalyst.
4. The method for preparing a rare-earth ion-doped modified upconversion photocatalyst according to claim 2, characterized in that, The hydrothermal or solvothermal synthesis includes the following steps: S2.1: Take a bismuth source, a fluorine source, and a titanium source in a molar ratio of 1-5:1:2-10; then dissolve the bismuth source and the fluorine source in water or mannitol solution and stir evenly to obtain a bismuth-fluorine mixture; at the same time, dissolve the titanium source in water or mannitol solution and stir evenly to obtain a titanium source mixture; then add the bismuth-fluorine mixture to the titanium source mixture and adjust the pH of the solution to 8-12 to obtain the initial solution; S2.2: Add activator and sensitizer to the initial solution, stir evenly, transfer the solution to a polytetrafluoroethylene liner and place it in an oven at 160-250℃ for 4-24 hours for reaction. After the reaction is completed, wash and dry to obtain the rare earth ion doped modified upconversion photocatalyst.
5. The method for preparing a rare-earth ion-doped modified upconversion photocatalyst according to claim 3, characterized in that, In S1.2, the molar ratio of the added precursor BiOF to TiO2 is 0.5 to 1:1; the molar ratio of the added activator, precursor BiOF and sensitizer is 0.5 to 2:100:1 to 10.
6. A method for preparing a rare-earth ion-doped modified upconversion photocatalyst according to claim 3 or 4, characterized in that, The activator is Er 3+ or Tm 3+ Or Ho 3+ The sensitizer is Yb 3+ or Nd 3+ .
7. The method for preparing a rare-earth ion-doped modified upconversion photocatalyst according to claim 4, characterized in that, In S2.1, the bismuth source is one or more of bismuth nitrate pentahydrate, bismuth carbonate, bismuth phosphate, and bismuth sulfate; the fluorine source is one or more of potassium fluoride, sodium fluoride, and ammonium fluoride; and the titanium source is one or more of titanium dioxide, titanium tetrachloride, and tetrabutyl titanate.
8. The method for preparing a rare-earth ion-doped modified upconversion photocatalyst according to claim 4, characterized in that, In S2.2, the molar ratio of the added activator, bismuth source and sensitizer is 0.5-2:100:1-10.
9. An application of a rare-earth ion-doped modified upconversion photocatalyst, characterized in that, The catalyst described herein serves as a photocatalyst in the degradation of organic dyes, endocrine substances, antibiotics, and heavy metal pollutants.