A method for preparing dendritic ternary SrCO3-TiO2 / CdS composite material, the resulting material, and its applications.
By in-situ growing CdS nanoparticles on the surface of SrCO3-TiO2 composite particles to form a dendritic ternary SrCO3-TiO2/CdS composite structure, the problems of narrow photoresponse range and low quantum efficiency of TiO2 photocatalytic materials are solved, and the effects of efficient visible light photocatalysis for hydrogen peroxide production and degradation of oxytetracycline are achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HUAIYIN INSTITUTE OF TECHNOLOGY
- Filing Date
- 2023-12-28
- Publication Date
- 2026-05-26
Smart Images
Figure CN117983265B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of inorganic nanomaterial preparation technology, and relates to the preparation of an inorganic composite material for photocatalytic synthesis of hydrogen peroxide and for antibiotic degradation. In particular, it relates to the preparation of a dendritic ternary SrCO3-TiO2 / CdS composite material, the obtained SrCO3-TiO2 / CdS composite material, and the application of the obtained material in visible light photocatalytic synthesis of hydrogen peroxide and simultaneous degradation of oxytetracycline. Background Technology
[0002] With rapid industrialization, energy crises and environmental pollution have become increasingly serious. Hydrogen peroxide, as a green oxidant and sustainable energy carrier, is widely used in chemical synthesis, bleaching, food, and environmental remediation. In recent years, photocatalysis technology based on semiconductor materials has been able to utilize inexhaustible solar energy to achieve the photocatalytic production of hydrogen peroxide with the advantages of low energy consumption and simple operation.
[0003] Among all semiconductor materials, TiO2 stands out as a photocatalytic material due to its biological inertness, chemical stability, resistance to photocorrosion, long-term stability, and high photocatalytic efficiency.
[0004] Oxytetracycline (OTC) is a broad-spectrum antibiotic widely used worldwide to treat diseases and promote livestock growth. However, due to its overuse, it is frequently detected in diverse aquatic environments around the world, potentially leading to the development of drug-resistant bacteria and antibiotic resistance genes (ARGs), which could have adverse effects on human health and ecosystem stability.
[0005] With the widespread production and application of oxytetracycline, human consumption and dependence on it are increasing daily. However, due to the structural characteristics and special properties of oxytetracycline, conventional wastewater treatment processes cannot effectively remove it from wastewater. Therefore, the development of a novel wastewater treatment technology to improve the removal efficiency of oxytetracycline in wastewater has attracted much attention from researchers.
[0006] Studies have shown that TiO2, a semiconductor material, has many advantages in degrading organic pollutants in wastewater. The degradation mechanism is as follows: (1) Under light irradiation, TiO2 photocatalytic material accepts energy greater than the band gap, and electrons jump from the valence band to the conduction band; (2) Due to the electron jump, positively charged holes are generated in the valence band, and highly active electrons are generated in the conduction band, forming electron-hole pairs; (3) Holes and electrons are transferred to the TiO2 surface, capturing H2O or OH- and dissolved oxygen O2 adsorbed on its surface, respectively, to generate free radicals and oxygen negative ions with high oxidation performance, thereby degrading and removing organic pollutants.
[0007] However, TiO2 itself also has many drawbacks, which seriously affect its development in photocatalytic hydrogen peroxide production and degradation of organic or inorganic pollutants. Therefore, modifying TiO2 to develop a novel heterojunction composite photocatalytic material is necessary to broaden the photoresponse range of the composite material, improve the quantum efficiency of the overall composite photocatalytic system, and achieve a significant increase in photocatalytic activity. This will have important implications for hydrogen peroxide production and the degradation of oxytetracycline (OTC) in wastewater. Summary of the Invention
[0008] To address the problems existing in the prior art, the present invention aims to provide a method for preparing a dendritic ternary SrCO3-TiO2 / CdS composite material. This method employs an in-situ growth method to grow CdS nanoparticles on the surface of SrCO3-TiO2 composite particles, forming a dendritic ternary SrCO3-TiO2 / CdS composite material. This material can be used for the catalytic generation of hydrogen peroxide under visible light and the simultaneous degradation of oxytetracycline.
[0009] This invention is achieved through the following technical solution:
[0010] A method for preparing a dendritic ternary SrCO3-TiO2 / CdS composite material, the specific steps of which are as follows:
[0011] Weigh a certain mass of tetrabutyl titanate into a certain volume of deionized water, then add a certain mass of Sr(NO3)2 under stirring conditions, and continue stirring for 5-10 min. Next, measure a certain volume of NaOH solution of a certain concentration and slowly add it dropwise into the above mixture, and stir at a certain temperature for 1-3 h. Transfer the stirred mixture to a hydrothermal reactor and react at a certain temperature for a period of time. After cooling to room temperature, centrifuge and wash several times, vacuum dry and grind to obtain SrCO3-TiO2 composite particles.
[0012] A certain mass of SrCO3-TiO2 composite particles was weighed and dispersed in a certain volume of deionized water. The mixture was stirred for 30-60 min and sonicated for 10-20 min to obtain a uniformly dispersed suspension. Then, a certain mass of Cd(NO3)2∙4H2O was weighed and added to the suspension under stirring. The mixture was stirred for 5-10 min and sonicated for 10-20 min. Next, a certain mass of CH4N2S was weighed and added to the suspension. The mixture was stirred for 5-10 min and sonicated for 10-20 min. Finally, the suspension was transferred to a hydrothermal reactor and reacted at a certain temperature for a period of time. After cooling to room temperature, the mixture was centrifuged and washed several times. After vacuum drying and grinding, a dendritic ternary SrCO3-TiO2 / CdS composite material was obtained.
[0013] A further technical improvement of this invention is:
[0014] In step (1), the ratio of tetrabutyl titanate, H2O, Sr(NO3)2, and NaOH aqueous solution is 0.4-3 g : 30-100 mL : 0.015-0.43 g : 1-3 mL, wherein the concentration of NaOH solution is 1-3 mol / L. The stirring reaction temperature is 15-25℃, the hydrothermal reaction temperature is 180-220℃, and the reaction time is 10-14 h. The mass ratio of SrCO3 in the obtained SrCO3-TiO2 composite particles is 10%-30%.
[0015] A further technical improvement of this invention is:
[0016] In step (2), the ratio of SrCO3-TiO2, H2O, Cd(NO3)2∙4H2O, and CH4N2S is 0.1-1g : 30-300 mL : 0.85-40g : 0.21-10g. The hydrothermal reaction temperature is 180-220℃, and the reaction time is 6-12h.
[0017] Furthermore, the SrCO3-TiO2 / CdS composite structure material is composed of SrCO3-TiO2 composite particles and CdS. In the dendritic ternary SrCO3-TiO2 / CdS composite structure material, the mass ratio of CdS is 80%-95%.
[0018] A further improvement of the present invention is as follows:
[0019] The application of the SrCO3-TiO2 / CdS composite material in the production of hydrogen peroxide and simultaneous degradation of oxytetracycline under visible light.
[0020] Furthermore, when the mass ratio of CdS nanoparticles in the composite material is 91%, the yield of hydrogen peroxide reaches 3267.87 μmol·h⁻¹. -1 ·g -1 The degradation rate of oxytetracycline is 100%.
[0021] Compared with the prior art, the present invention has the following obvious advantages:
[0022] (1) A novel dendritic ternary SrCO3-TiO2 / CdS composite structure material is proposed. The present invention constructs a novel dendritic ternary SrCO3-TiO2 / CdS composite structure material system based on a composite heterojunction system with CdS as the unit. Due to the construction of the composite structure and its unique morphology, it not only improves the light-harvesting ability of CdS and increases the utilization rate of visible light, but also realizes the rapid separation of photogenerated electron-hole pairs and inhibits their recombination. In addition, it broadens the photoresponse range of the composite material and improves the quantum efficiency of the overall composite photocatalytic system, thus achieving the goal of significantly improving photocatalytic activity.
[0023] (2) This patent is the first to propose an in-situ growth method to grow CdS on the surface of SrCO3-TiO2 composite particles, and finally form a dendritic ternary SrCO3-TiO2 / CdS composite material. Due to the unique synergistic effect between SrCO3-TiO2 / CdS, the SrCO3-TiO2 / CdS nanocomposite material can effectively separate electron-hole pairs and inhibit their recombination. It also broadens the light response range of the composite material, increases the utilization rate of visible light, and ultimately improves the quantum efficiency of the overall composite photocatalytic system.
[0024] (3) A simple preparation process is used to synthesize dendritic SrCO3-TiO2 / CdS composite material. The preparation material is abundant, the operation process is simple, the reaction time is short, and it is easy to industrialize. It can also effectively utilize visible light to produce hydrogen peroxide and degrade oxytetracycline. This material has great application prospects in solving environmental pollution and synthesizing chemicals. Attached Figure Description
[0025] Figure 1 These are TEM images of TiO2, SrCO3-TiO2 composite particles, CdS, and SrCO3-TiO2 / CdS samples prepared according to Example 1.
[0026] Figure 2 The images show the XRD patterns of TiO2 and CdS prepared in Example 1, and SrCO3-TiO2 composite particle samples and SrCO3-TiO2 / CdS samples prepared in Example 2.
[0027] Figure 3 These are DRS images of TiO2 and CdS prepared in Example 1, and SrCO3-TiO2 composite particle samples and SrCO3-TiO2 / CdS samples prepared in Example 3.
[0028] Figure 4 These are PL plots of the CdS obtained in Example 1 and the SrCO3-TiO2 / CdS samples prepared in Examples 4, 5, and 6;
[0029] Figure 5 EIS images of TiO2 and CdS prepared in Example 1, and SrCO3-TiO2 composite particle samples and SrCO3-TiO2 / CdS samples prepared in Example 4;
[0030] Figure 6 These are TPR images of TiO2 and CdS prepared in Example 1, and SrCO3-TiO2 and SrCO3-TiO2 / CdS samples prepared in Example 5. Detailed Implementation
[0031] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited thereto.
[0032] In this invention, the simultaneous degradation of oxytetracycline during hydrogen peroxide production was conducted in a DW-03 photochemical reactor. A 250W xenon lamp was used as a simulated solar energy source, and ultraviolet light was filtered out. The degradation efficiency of the dendritic ternary SrCO3-TiO2 / CdS composite material on pollutants and the yield of hydrogen peroxide were evaluated under visible light. The specific steps were as follows: 60 mL (15 mg / L) of oxytetracycline was added to the reactor and its initial value was measured. Then, 20 mg of the composite material was added. After the reaction was carried out in the dark for 30 min to reach adsorption-desorption equilibrium, the reactor was illuminated for 120 min. Samples were taken every 20 min during this period. After centrifugation, the supernatant was collected, and the absorbance of the supernatant was measured at the maximum absorption wavelength of the pollutant using a UV-Vis spectrophotometer. The supernatant was then developed using iodine titration and diluted 10 times, and the absorbance of the solution was measured again using a UV-Vis spectrophotometer. Based on the absorbance before and after illumination, the degradation rate of the oxytetracycline solution η = (C0 - C...) was calculated. t ) / C0×100%, where C0 is the absorbance of the sample at the beginning of illumination, C t The absorbance of the sample after 30 min of illumination is given. The yield and rate of hydrogen peroxide are calculated based on the absorbance after color development by iodine titration. Example 1
[0033] (1) First, 0.4 g of tetrabutyl titanate was weighed into 30 mL of deionized water. Then, 0.015 g of Sr(NO3)2 was added under stirring. The mixture was stirred for 5-10 min. Next, 1 mL of 1 mol / L NaOH solution was slowly added dropwise to the mixture. The mixture was stirred at 15 °C for 1-3 h. The stirred mixture was then transferred to a hydrothermal reactor and reacted at 180 °C for 14 h. After cooling to room temperature, the mixture was centrifuged and washed several times, then vacuum dried and ground to obtain SrCO3-TiO2 composite particles, wherein the mass ratio of SrCO3 in the SrCO3-TiO2 composite particles was 10%. For comparison, pure TiO2 nanoparticles were prepared under the same conditions without the addition of Sr(NO3)2.
[0034] (2) Weigh 0.1 g of SrCO3-TiO2 composite particles and disperse them in 30 mL of deionized water. Stir for 30-60 min and sonicate for 10-20 min to obtain a uniformly dispersed suspension. Then weigh 0.85 g of Cd(NO3)2∙4H2O and add it to the above suspension under stirring. Stir for 5-10 min and sonicate for 10-20 min. Next, weigh 0.21 g of CH4N2S and add it to the above suspension. Stir for 5-10 min and sonicate for 10-20 min. Finally, transfer the suspension to a hydrothermal reactor and react at 220℃ for 6 h. After cooling to room temperature, centrifuge and wash several times, vacuum dry and grind to obtain a dendritic ternary SrCO3-TiO2 / CdS composite material, wherein the mass ratio of CdS in the composite material is 80%. For comparison, pure CdS material was prepared under the same conditions without the addition of SrCO3-TiO2 composite particles.
[0035] TEM images of the TiO2, SrCO3-TiO2, CdS, and SrCO3-TiO2 / CdS samples prepared according to Example 1 are attached. Figure 1 As shown, attached Figure 1 It can be seen that pure TiO2 has a blocky nanoparticle structure with a size ranging from 5 to 20 nm, while SrCO3-TiO2 has an elliptical particle structure with a size ranging from 80 to 200 nm, indicating that the SrCO3-TiO2 composite particles were successfully composited. For pure CdS, a dendritic structure of approximately 0.5 μm in size was observed. During the preparation process, dendritic CdS grew in situ on the SrCO3-TiO2 nanoparticles, forming a branched dendritic structure of approximately 1 μm in size with the SrCO3-TiO2 nanoparticles as fulcrums, indicating that the SrCO3-TiO2 particles and CdS were successfully composited.
[0036] The CdS, TiO2 samples, and SrCO3-TiO2 composite particles obtained in Example 1 were irradiated with visible light in OTC solution for 120 min, and the hydrogen peroxide yields were 1316.84 μmol·h⁻¹, respectively. -1 ·g -1 58.91 μmol·h -1 ·g -1 , and 119.87 μmol·h -1 ·g -1 The degradation efficiencies of oxytetracycline were 80%, 68%, and 75%, respectively. The hydrogen peroxide yield of the SrCO3-TiO2 / CdS composite material obtained in Example 1 reached 2002.13 μmol·h⁻¹. -1 ·g -1 The photocatalytic activity of the composite material was 1.52 times, 33.9 times, and 16.67 times that of the monomeric CdS, TiO2, and the composite material SrCO3-TiO2, respectively. Its degradation efficiency for oxytetracycline reached 94.89%, which was 1.19 times, 1.4 times, and 1.27 times that of the monomeric CdS, TiO2, and the composite material SrCO3-TiO2, respectively. This demonstrates that the photocatalytic activity of the composite sample, especially the rate of hydrogen peroxide production, was higher than that of the monomeric CdS and the binary SrCO3-TiO2 composite particles. Example 2
[0037] (1) First, weigh 0.6 g of tetrabutyl titanate into 50 mL of deionized water, then add 0.036 g of Sr(NO3)2 under stirring, and continue stirring for 5-10 min. Next, slowly add 2 mL of 1 mol / L NaOH solution to the above mixture, and stir at 20 ℃ for 1-3 h. Transfer the stirred mixture to a hydrothermal reactor and react at 190 ℃ for 12 h. After cooling to room temperature, centrifuge and wash several times, vacuum dry and grind to obtain SrCO3-TiO2 composite particles, wherein the mass ratio of SrCO3 in the composite particles is 14%.
[0038] (2) Weigh 0.3 g of SrCO3-TiO2 composite particles and disperse them in 50 mL of deionized water. Stir for 30-60 min and sonicate for 10-20 min to obtain a uniformly dispersed suspension. Then weigh 3.62 g of Cd(NO3)2∙4H2O and add it to the above suspension under stirring. Stir for 5-10 min and sonicate for 10-20 min. Next, weigh 0.9 g of CH4N2S and add it to the above suspension. Stir for 5-10 min and sonicate for 10-20 min. Finally, transfer the suspension to a hydrothermal reactor and react at 215℃ for 6 h. After cooling to room temperature, centrifuge and wash several times, vacuum dry and grind to obtain a dendritic ternary SrCO3-TiO2 / CdS composite material, wherein the mass ratio of CdS in the composite material is 85%.
[0039] The SrCO3-TiO2 composite particle sample obtained in Example 2, after being irradiated with visible light in OTC solution for 120 min, showed a degradation efficiency of 69% for oxytetracycline and a hydrogen peroxide yield of 109.75 μmol·h⁻¹. -1 ·g -1 The SrCO3-TiO2 / CdS composite material obtained in Example 2 showed a degradation efficiency of 96.15% for oxytetracycline and a hydrogen peroxide yield of 2022.53 μmol·h⁻¹. -1 ·g -1 The H2O2 production rate of this composite material was 1.54 times, 34.27 times, and 18.38 times that of the monomer CdS, TiO2, and the composite material SrCO3-TiO2, respectively. Its degradation efficiency for oxytetracycline was 1.2 times, 1.41 times, and 1.39 times that of the monomer CdS, TiO2, and the composite material SrCO3-TiO2, respectively.
[0040] Appendix of the present invention Figure 2The XRD patterns of TiO2 and CdS prepared according to Example 1, and SrCO3-TiO2 composite particles and SrCO3-TiO2 / CdS samples prepared according to Example 2 are shown. The diffraction peaks of pure TiO2 at 2θ = 25.3° and 47.9° completely match the (111) and (200) crystal planes of anatase TiO2. The diffraction peaks of pure CdS at 2θ = 26.4°, 30.4°, 43.7° and 51.8° completely match the (111), (200), (220) and (311) crystal planes of cubic CdS, and there are no other impurity peaks, indicating that the two monomers have been successfully synthesized. In the XRD pattern of the SrCO3-TiO2 composite particles, in addition to the diffraction peaks of TiO2, characteristic peaks of monomeric SrCO3 were also observed at 2θ = 25.2°, 25.7°, 36.6°, and 44.1°, indicating that SrCO3 and TiO2 have been successfully composited. In the XRD pattern of the SrCO3-TiO2 / Cd composite structure, in addition to the diffraction peaks of CdS, the (111) and (200) crystal planes of TiO2 and the (022) crystal plane of SrCO3 were also detected, indicating that SrCO3-TiO2 and CdS materials have been successfully composited. Example 3
[0041] (1) First, weigh 0.8 g of tetrabutyl titanate into 50 mL of deionized water, then add 0.059 g of Sr(NO3)2 under stirring, and continue stirring for 5-10 min. Next, slowly add 2 mL of 1 mol / L NaOH solution to the above mixture, and stir at 15 ℃ for 1-3 h. Transfer the stirred mixture to a hydrothermal reactor and react at 195 ℃ for 13 h. After cooling to room temperature, centrifuge and wash several times, vacuum dry and grind to obtain SrCO3-TiO2 composite particles, wherein the mass ratio of SrCO3 in the composite structure material is 18%.
[0042] (2) Weigh 0.5 g of SrCO3-TiO2 composite particles and disperse them in 50 mL of deionized water. Stir for 30-60 min and sonicate for 10-20 min to obtain a uniformly dispersed suspension. Then weigh 7.83 g of Cd(NO3)2∙4H2O and add it to the above suspension under stirring. Stir for 5-10 min and sonicate for 10-20 min. Next, weigh 1.93 g of CH4N2S and add it to the above suspension. Stir for 5-10 min and sonicate for 10-20 min. Finally, transfer the suspension to a hydrothermal reactor and react at 210℃ for 7 h. After cooling to room temperature, centrifuge and wash several times, vacuum dry and grind to obtain a dendritic ternary SrCO3-TiO2 / CdS composite material, wherein the mass ratio of CdS in the composite material is 88%.
[0043] The SrCO3-TiO2 composite particle sample obtained in Example 3, after being irradiated with visible light in OTC solution for 120 min, showed a degradation efficiency of 71% for oxytetracycline and a hydrogen peroxide yield of 123.66 μmol·h⁻¹. -1 ·g -1 The SrCO3-TiO2 / CdS composite material obtained in Example 1 achieved a degradation efficiency of 97.14% for oxytetracycline and a hydrogen peroxide yield of 2642.33 μmol·h⁻¹. -1 ·g -1 The H2O2 production rate of this composite material was 2.12 times, 44.78 times, and 21.48 times that of the monomer CdS, TiO2, and the composite material SrCO3-TiO2, respectively. Its degradation efficiency for oxytetracycline was 1.42 times, 1.38 times, and 1.37 times that of the monomer CdS, TiO2, and the composite material SrCO3-TiO2, respectively.
[0044] Appendix of the present invention Figure 3 The DRS diagrams of TiO2 and CdS prepared according to Example 1, and SrCO3-TiO2 composite particle samples and SrCO3-TiO2 / CdS samples prepared according to Example 3 are shown in the figure. It can be seen from the figure that the light absorption capacity of SrCO3-TiO2 / CdS composite material is significantly improved compared with the single TiO2, single CdS and SrCO3-TiO2 samples, indicating that the ternary composite structure has a stronger light-harvesting ability. Example 4
[0045] (1) First, weigh 1.1 g of tetrabutyl titanate into 60 mL of deionized water, then add 0.105 g of Sr(NO3)2 under stirring, and continue stirring for 5-10 min. Next, slowly add 2 mL of 2 mol / L NaOH solution to the above mixture, and stir at 20 ℃ for 1-3 h. Transfer the stirred mixture to a hydrothermal reactor and react at 200 ℃ for 11 h. After cooling to room temperature, centrifuge and wash several times, vacuum dry and grind to obtain SrCO3-TiO2 composite particles, wherein the mass ratio of SrCO3 in the composite structure material is 22%.
[0046] (2) Weigh 0.8 g of SrCO3-TiO2 composite particles and disperse them in 80 mL of deionized water. Stir for 30-60 min and sonicate for 10-20 min to obtain a uniformly dispersed suspension. Then weigh 17.27 g of Cd(NO3)2∙4H2O and add it to the above suspension under stirring. Stir for 5-10 min and sonicate for 10-20 min. Next, weigh 4.26.5 g of CH4N2S and add it to the above suspension. Stir for 5-10 min and sonicate for 10-20 min. Finally, transfer the suspension to a hydrothermal reactor and react at 200℃ for 8 h. After cooling to room temperature, centrifuge and wash several times, vacuum dry and grind to obtain a dendritic ternary SrCO3-TiO2 / CdS composite material, wherein the mass ratio of CdS in the composite material is 91%.
[0047] The SrCO3-TiO2 composite particle sample obtained in Example 4, after being irradiated with visible light in OTC solution for 120 min, showed a degradation efficiency of 75% for oxytetracycline and a hydrogen peroxide yield of 134.87 μmol·h⁻¹. -1 ·g -1 The SrCO3-TiO2 / CdS composite material obtained in Example 4 achieved a 100% degradation efficiency for oxytetracycline, with a hydrogen peroxide yield of 3267.87 μmol·h⁻¹. -1 ·g -1 The H2O2 production rate of this composite material was 2.48 times, 55.47 times, and 22.23 times that of the monomeric CdS, TiO2, and the composite material SrCO3-TiO2, respectively. Its degradation efficiency for oxytetracycline was 1.25 times, 1.47 times, and 1.33 times that of the monomeric CdS, TiO2, and the composite material SrCO3-TiO2 particles, respectively.
[0048] Appendix of the present invention Figure 4 The photoluminescence (PL) plots of the CdS prepared according to Example 1 and the SrCO3-TiO2 / CdS samples prepared according to Example 4 show that, compared with the monomer, the photoluminescence peak intensity of SrCO3-TiO2 / CdS is significantly reduced compared with pure CdS. This indicates that after constructing the composite structure, the recombination rate of photogenerated electrons and holes is significantly reduced, promoting the transfer of photogenerated carriers and thus improving the photocatalytic performance of the composite material. This also shows that this is one of the factors that improve the photocatalytic performance.
[0049] Appendix of the present invention Figure 5The EIS images of TiO2 and CdS prepared according to Example 1 and SrCO3-TiO2 and SrCO3-TiO2 / CdS samples prepared according to Example 4 are shown in the figure. It can be seen from the figure that compared with the monomeric CdS, TiO2 and SrCO3-TiO2 composite particles, the SrCO3-TiO2 / CdS composite material has a smaller radius of curvature, indicating that it has the lowest resistance during charge transfer and the highest quantum yield of photogenerated carriers, which is beneficial to the improvement of catalytic performance. Example 5
[0050] (1) First, weigh 1.5 g of tetrabutyl titanate into 90 mL of deionized water, then add 0.18 g of Sr(NO3)2 under stirring, and continue stirring for 5-10 min. Next, slowly add 2 mL of 3 mol / L NaOH solution to the mixture and stir at 15 °C for 1-3 h. Transfer the stirred mixture to a hydrothermal reactor and react at 210 °C for 11 h. After cooling to room temperature, centrifuge and wash several times, vacuum dry and grind to obtain SrCO3-TiO2 composite particles, wherein the mass ratio of SrCO3 in the composite structure material is 26%.
[0051] (2) Weigh 0.9 g of SrCO3-TiO2 composite particles and disperse them in 150 mL of deionized water. Stir for 30-60 min and sonicate for 10-20 min to obtain a uniformly dispersed suspension. Then weigh 25.53 g of Cd(NO3)2∙4H2O and add it to the above suspension under stirring. Stir for 5-10 min and sonicate for 10-20 min. Next, weigh 6.3 g of CH4N2S and add it to the above suspension. Stir for 5-10 min and sonicate for 10-20 min. Finally, transfer the suspension to a hydrothermal reactor and react at 190℃ for 10 h. After cooling to room temperature, centrifuge and wash several times, vacuum dry and grind to obtain a dendritic ternary SrCO3-TiO2 / CdS composite material, wherein the mass ratio of CdS in the composite material is 93%.
[0052] The SrCO3-TiO2 composite particle sample obtained in Example 5, after being irradiated with visible light in OTC solution for 120 min, showed a degradation efficiency of 73% for oxytetracycline and a hydrogen peroxide yield of 113.23 μmol·h⁻¹. -1 ·g -1 The SrCO3-TiO2 / CdS composite material obtained in Example 5 achieved a degradation efficiency of 93.59% for oxytetracycline and a hydrogen peroxide yield of 2552.33 μmol·h⁻¹. -1 ·g -1The H2O2 production rate of this composite material was 1.94 times, 43.33 times, and 22.54 times that of the monomer CdS, TiO2, and the composite material SrCO3-TiO2, respectively. Its degradation efficiency for oxytetracycline was 1.17 times, 1.38 times, and 1.27 times that of the monomer CdS, TiO2, and the composite material SrCO3-TiO2, respectively.
[0053] Appendix of the present invention Figure 4 The photoluminescence (PL) plots of the CdS prepared according to Example 1 and the SrCO3-TiO2 / CdS samples prepared according to Example 5 show that, compared with the monomer, the photoluminescence peak intensity of SrCO3-TiO2 / CdS is significantly reduced compared with pure CdS. This indicates that after constructing the composite structure, the recombination rate of photogenerated electrons and holes is significantly reduced, promoting the transfer of photogenerated carriers and thus improving the photocatalytic performance of the composite material. This also shows that this is one of the factors that improve the photocatalytic performance.
[0054] Appendix of the present invention Figure 6 The transient photocurrent response (TPR) spectra of the SrCO3-TiO2 sample and the SrCO3-TiO2 / CdS sample prepared according to Example 5 are shown in the figure. As can be seen from the figure, compared with the monomeric CdS and TiO2, the SrCO3-TiO2 / CdS composite material exhibits a higher light flux density than SrCO3-TiO2 and pure CdS, which can effectively accelerate photoinduced charge migration, improve the separation efficiency of the photogenerated carrier, and significantly improve photocatalytic activity. Example 6
[0055] (1) First, weigh 3 g of tetrabutyl titanate into 100 mL of deionized water, then add 0.43 g of Sr(NO3)2 under stirring, and continue stirring for 5-10 min. Next, slowly add 3 mL of 3 mol / L NaOH solution to the above mixture, and stir at 25 ℃ for 1-3 h. Transfer the stirred mixture to a hydrothermal reactor and react at 220 ℃ for 10 h. After cooling to room temperature, centrifuge and wash several times, vacuum dry and grind to obtain SrCO3-TiO2 composite particles, wherein the mass ratio of SrCO3 in SrCO3-TiO2 composite particles is 30%.
[0056] (2) Weigh 1 g of SrCO3-TiO2 composite particles and disperse them in 300 mL of deionized water. Stir for 30-60 min and sonicate for 10-20 min to obtain a uniformly dispersed suspension. Then weigh 40 g of Cd(NO3)2∙4H2O and add it to the above suspension under stirring. Stir for 5-10 min and sonicate for 10-20 min. Next, weigh 10 g of CH4N2S and add it to the above suspension. Stir for 5-10 min and sonicate for 10-20 min. Finally, transfer the suspension to a hydrothermal reactor and react at 180℃ for 12 h. After cooling to room temperature, centrifuge and wash several times, vacuum dry and grind to obtain a dendritic ternary SrCO3-TiO2 / CdS composite material, wherein the mass ratio of CdS in the composite material is 95%.
[0057] Appendix of the present invention Figure 4 The photoluminescence (PL) plots of the CdS prepared according to Example 1 and the SrCO3-TiO2 / CdS samples prepared according to Example 6 show that, compared with the monomer, the photoluminescence peak intensity of SrCO3-TiO2 / CdS is significantly reduced compared with pure CdS. This indicates that after constructing the composite structure, the recombination rate of photogenerated electrons and holes is significantly reduced, promoting the transfer of photogenerated carriers and thus improving the photocatalytic performance of the composite material. This also shows that this is one of the factors that improve the photocatalytic performance.
[0058] The SrCO3-TiO2 composite particles obtained in Example 6, after being irradiated with visible light in OTC solution for 120 min, showed a degradation efficiency of 70% for oxytetracycline and a hydrogen peroxide yield of 87.25 μmol·h⁻¹. -1 ·g -1 The SrCO3-TiO2 / CdS composite material obtained in Example 6 achieved a degradation efficiency of 93.05% for oxytetracycline and a hydrogen peroxide yield of 2002.54 μmol·h⁻¹. -1 ·g -1 The H2O2 production rate of this composite material was 1.52 times, 33.95 times, and 22.73 times that of the monomer CdS, TiO2, and the composite material SrCO3-TiO2, respectively. Its degradation efficiency for oxytetracycline was 1.16 times, 1.37 times, and 1.34 times that of the monomer CdS, TiO2, and the composite material SrCO3-TiO2, respectively.
Claims
1. A method for preparing a dendritic ternary SrCO3-TiO2 / CdS composite material, characterized in that, Includes the following steps: (1) Tetrabutyl titanate and Sr(NO3)2 were mixed and dissolved in deionized water, and NaOH solution was added dropwise. After the addition was completed, the mixture was stirred at a certain temperature for 1-3 h. The mixed solution after stirring was transferred to a hydrothermal reactor and reacted at a certain temperature for a period of time. After cooling to room temperature, the mixture was centrifuged and washed several times, then vacuum dried and ground to obtain SrCO3-TiO2 composite particles. (2) The SrCO3-TiO2 composite particles obtained in step (1) are dispersed together with Cd(NO3)2∙4H2O and CH4N2S in a certain volume of deionized water to obtain a uniformly dispersed suspension. The obtained suspension is transferred to a hydrothermal reactor and reacted at a certain temperature for a period of time. After cooling to room temperature, it is centrifuged and washed several times, vacuum dried and ground to obtain a dendritic ternary SrCO3-TiO2 / CdS composite material. In step (1), the ratio of tetrabutyl titanate, H2O, Sr(NO3)2 and NaOH aqueous solution is 0.4-3 g: 30-100 mL: 0.015-0.43 g: 1-3 mL, wherein the concentration of NaOH solution is 1-3 mol / L.
2. The method for preparing a dendritic ternary SrCO3-TiO2 / CdS composite material according to claim 1, characterized in that: In step (1), the stirring reaction temperature is 15-25℃, the hydrothermal reaction temperature is 180-220℃, and the reaction time is 10-14h; the mass ratio of SrCO3 in the obtained SrCO3-TiO2 composite particles is 10%-30%.
3. The method for preparing a dendritic ternary SrCO3-TiO2 / CdS composite material according to claim 1, characterized in that: In step (2), the ratio of SrCO3-TiO2, H2O, Cd(NO3)2∙4H2O and CH4N2S is 0.1-1g: 30-300 mL: 0.85-40g: 0.21-10g.
4. The method for preparing a dendritic ternary SrCO3-TiO2 / CdS composite material according to claim 1, characterized in that: In step (2), the hydrothermal reaction temperature is 180-220℃ and the reaction time is 6-12h.
5. The method for preparing a dendritic ternary SrCO3-TiO2 / CdS composite material according to claim 1, characterized in that: In step (2), the process of obtaining the suspension is as follows: a certain mass of SrCO3-TiO2 composite particles are weighed and dispersed in a certain volume of deionized water, stirred for 30-60 min, and sonicated for 10-20 min. Then, a certain mass of Cd(NO3)2∙4H2O is weighed and added to the above suspension under stirring conditions, stirred for 5-10 min, and sonicated for 10-20 min. Next, a certain mass of CH4N2S is weighed and added to the above suspension, stirred for 5-10 min, and sonicated for 10-20 min. Finally, a uniformly dispersed suspension is obtained.
6. A dendritic ternary SrCO3-TiO2 / CdS composite material prepared by the method according to any one of claims 1-5, characterized in that: In the dendritic ternary SrCO3-TiO2 / CdS composite material, CdS accounts for 80%-95% of the mass.
7. The application of the dendritic ternary SrCO3-TiO2 / CdS composite material as described in claim 6 in the visible light photocatalytic generation of hydrogen peroxide and simultaneous degradation of oxytetracycline.