Preparation method of strontium titanate with special morphology
Strontium titanate nanotubes were prepared by a hydrothermal method. By utilizing the ion exchange reaction between Sr-based ions and titanate nanotubes, the preparation problem of strontium titanate nanotubes was solved, the photocatalytic CO2 reduction efficiency and CO2 adsorption capacity were improved, and low-cost and high-efficiency photocatalytic performance was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-07
- Publication Date
- 2026-04-10
AI Technical Summary
There are few existing methods for preparing strontium titanate nanotubes, making it difficult to achieve two-dimensional layered nanostructures, which leads to low photocatalytic CO2 reduction efficiency.
Strontium titanate nanotubes were prepared via a hydrothermal method using protonated titanate nanotubes as precursors. Sr-based ions were then used to conduct an ion exchange reaction with the titanate nanotubes to form strontium titanate nanotubes with unique morphologies, thereby enhancing charge separation efficiency and active site density.
It improves the photocatalytic CO2 reduction capacity, enhances the adsorption and conversion performance of CO2, and the preparation method is simple, low-cost, and the solvent can be recycled.
Smart Images
Figure CN121823644A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of photocatalytic materials technology, and in particular to a method for preparing strontium titanate. Background Technology
[0002] The consumption of fossil fuels has disrupted the carbon balance in nature, leading to unprecedented global warming, sea-level rise, and severe storms. Reducing carbon emissions and achieving a carbon cycle have become extensive research topics. Photocatalytic CO2 reduction, which converts clean solar energy into chemical energy and CO2 into high-value chemicals, represents a promising pathway. However, in the photocatalytic CO2 reduction process, the robust C=O group in the nonpolar CO2 molecule is difficult to activate effectively, resulting in low catalytic efficiency. Therefore, utilizing geometric engineering to synthesize nanomaterials with unique hierarchical structures to enhance CO2 adsorption and activation, thereby improving photocatalytic efficiency, has become a current research hotspot.
[0003] Currently, various nanostructured materials are being developed, such as: 0D nanomaterials represented by quantum dots; 1D nanomaterials represented by nanowires, nanorods, and nanotubes; 2D nanomaterials represented by nanosheets; and 3D nanomaterials represented by nanoflowers and nanospheres. As particle size decreases, the chemical activity of the materials is significantly enhanced. Among these nanomaterials, nanotubes have been extensively studied due to their high specific surface area, excellent light collection efficiency, high electron mobility, and unidirectional charge transfer. Strontium titanate (SrTiO3) is a typical ternary cubic perovskite oxide with a large nonlinear optical coefficient. Due to its low cost, high efficiency, long-lasting photostability, and corrosion resistance, it is considered one of the most attractive n-type semiconductor photocatalysts (E0). g SrTiO3 nanomaterials (with a viscosity of 3.2 eV) hold great potential in the field of photocatalytic CO2 reduction. To date, various microstructures of SrTiO3 nanomaterials have been prepared, including nanoparticles, nanorods, nanowires, nanospheres, and nanosheets. However, strontium titanate nanotubes have received little attention. Finding a simple and universal method to prepare two-dimensional layered nanostructured nanotubes remains a significant challenge. Summary of the Invention
[0004] To address the shortcomings of existing technologies, this invention provides a method for preparing strontium titanate with a special morphology, which can greatly improve photocatalytic performance and enhance the adsorption and conversion of CO2.
[0005] The objective of this invention is achieved as follows: a method for preparing strontium titanate with a special morphology, comprising the following steps:
[0006] Step 1) Weigh the set amount of rutile powder and dissolve it in NaOH solution. After ultrasonic treatment for a set time, transfer the resulting mixture to a high-pressure reactor for high-temperature reaction. After natural cooling, acid washing, centrifugation, and freeze drying, protonated titanate nanotubes (HTNT) are obtained.
[0007] Step 2) Weigh the set amount of protonated titanate nanotubes (HTNT) obtained in Step 1) and disperse them in an aqueous solution. While stirring continuously, add SrCl2·6H2O and NaOH. Transfer the resulting mixture to a high-pressure reactor for high-temperature reaction. After natural cooling, wash and dry to obtain strontium titanate nanotubes (STNT), strontium titanate nanoparticles (STNP), and nanorods (STNR).
[0008] Furthermore, in step 1), the amount of rutile powder is 1-3 g, the concentration of NaOH solution is 10 M, and the amount used is 80-90 mL.
[0009] Furthermore, in step 1), the ultrasonic treatment time is 30-60 min, the heating rate in the high-pressure reactor is 2-5°C / min, the holding time is 24-48 h, and the reaction temperature is 120-150°C.
[0010] Furthermore, in step 1), the pickling process involves washing with water and hydrochloric acid 3-5 times each.
[0011] Furthermore, in step 2), the amount of protonated titanate nanotubes (HTNT) is 0.5-2 g, and the amount of pure water in the aqueous solution is 50-70 mL.
[0012] Furthermore, in step 2), the amount of SrCl2·6H2O added is 0.334-13.36 g, and the amount of NaOH is 2-4 g.
[0013] Furthermore, in step 2), the reaction temperature inside the high-pressure reactor is 200-220℃, and the hydrothermal time is 0.5-12 h.
[0014] Furthermore, in step 2), the washing is performed by washing with water and ethanol 3-5 times each, and the drying is performed by vacuum drying for 24-48 hours at a temperature of 80-100℃.
[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0016] This invention utilizes protonated titanate nanotubes (HTNTs) as precursors and templates to prepare SrTiO3 nanotubes (STNTs) via a hydrothermal method. The titanate nanotubes contain zigzag ribbon-like knots formed by TiO6 octahedra and other TiO6 octahedra sharing four edges. Furthermore, the H... +It can undergo ion exchange reactions with other ions while maintaining its original structure. Therefore, Sr-based ionic compounds are used as Sr sources to react with the H+ of titanate nanotubes. + A displacement reaction occurs, completing the isomorphic transformation from titanate nanotubes to strontium titanate nanotubes, thereby improving charge separation efficiency, increasing the density of active sites, and enhancing the photocatalytic CO2 reduction capacity.
[0017] This invention highlights the strong redox properties, suitable band gap, low cost, and easily tunable structure of strontium titanate. STNP, STNR, and STNT photocatalysts with strong CO2 adsorption and good photocatalytic performance were prepared using a hydrothermal method. The preparation method provided by this invention is simple, the reaction is mild, and the solvent raw materials can be recycled industrially, effectively reducing product costs and demonstrating high practical value and promising application prospects. Attached Figure Description
[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.
[0019] Figure 1 The TEM spectrum of STNT prepared according to this invention.
[0020] Figure 2 The TEM spectrum of the STNP prepared according to this invention.
[0021] Figure 3 The TEM spectrum of the STNR prepared according to the present invention.
[0022] Figure 4 The XRD patterns of HTNT, STNT, STNP and STNR prepared according to the present invention.
[0023] Figure 5 A comparison chart showing the photocatalytic CO2 reduction to CO rates of STNT, STNP, and STNR prepared in this invention.
[0024] Figure 6 The graph shows the change in the amount of CO generated from the photocatalytic reduction of CO2 by STNT prepared in this invention over time. Detailed Implementation
[0025] 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.
[0026] Example 1
[0027] A method for preparing strontium titanate with a special morphology includes the following steps:
[0028] Step 1) Disperse 1 g of rutile powder in 80 mL of 10 mol L⁻¹ −1 The mixture was treated with NaOH solution and subjected to ultrasonic degradation for 30 min; then the mixture was transferred to a Teflonlined stainless steel autoclave, heated at a rate of 2 °C / min, and held at 120 °C for 24 h. After cooling to room temperature, it was treated with distilled water and 0.1 mol L⁻¹ −1 Wash with HCl solution until the pH reaches 8.0, centrifuge, and freeze-dry the precipitate to obtain HTNT.
[0029] Step 2) Suspend 0.5 g of lyophilized HTNT obtained in Step 1) in 50 mL of distilled water, then add 0.334 g of SrCl2·6H2O and 2 g of NaOH under vigorous stirring; after hydrothermal treatment at 200℃ for 0.5 h, filter and collect the precipitate, wash it 3 times with distilled water; finally, dry the precipitate at 80℃ for 24 h to obtain STNT.
[0030] Example 2
[0031] A method for preparing strontium titanate with a special morphology includes the following steps:
[0032] Step 1) Disperse 2 g of rutile powder in 85 mL of 10 mol L⁻¹ −1 The mixture was treated with sodium hydroxide solution and subjected to ultrasonic degradation for 45 min. The mixture was then transferred to a Teflonlined stainless steel autoclave and heated at 130°C for 36 h at a rate of 3 °C / min. After cooling to room temperature, it was treated with distilled water and 0.1 mol L⁻¹ −1 Wash with HCl solution until the pH reaches 8.0, centrifuge, and freeze-dry the precipitate to obtain HTNT.
[0033] Step 2) 1 g of lyophilized HTNT obtained in Step 1) was suspended in 60 mL of distilled water, and then 1.67 g of SrCl2·6H2O and 3 g of NaOH were added under vigorous stirring. After hydrothermal treatment at 210 °C for 3 h, the precipitate was collected by filtration and washed 4 times with distilled water. Finally, the precipitate was dried at 90 °C for 36 h to obtain STNP.
[0034] Example 3
[0035] A method for preparing strontium titanate with a special morphology includes the following steps:
[0036] Step 1) Disperse 3 g of rutile powder in 90 mL of 10 mol / L solution. −1 The mixture was treated with sodium hydroxide solution and subjected to ultrasonic degradation for 60 min. The mixture was then transferred to a Teflonlined stainless steel autoclave, heated at a rate of 5 °C / min, and maintained at 150 °C for 48 h. After cooling to room temperature, it was treated with distilled water and 0.1 mol L⁻¹ −1 Wash with HCl solution until the pH reaches 8.0, centrifuge, and freeze-dry the precipitate to obtain HTNT.
[0037] Step 2) 2 g of lyophilized HTNT obtained in Step 1) was suspended in 70 mL of distilled water, and then 13.36 g of SrCl2·6H2O and 4 g of NaOH were added with vigorous stirring. After hydrothermal treatment at 220 °C for 12 h, the precipitate was collected by filtration and washed 5 times with distilled water. Finally, the precipitate was dried at 100 °C for 48 h to obtain STNR.
[0038] The present invention will be further described below with reference to the accompanying drawings.
[0039] Figure 1 , Figure 2 and Figure 3 The TEM images of the STNTs, STNPs, and STNRs prepared in this example are shown. Clear nanotube, nanoparticle, and nanorod structures can be observed.
[0040] Figure 4XRD patterns of HTNTs, STNTs, STNPs, and STNRs prepared for this example. The XRD curve of HTNTs shows only three weak peaks at 23.7°, 28.7°, and 48.3°, corresponding to the (110), (130), and (200) crystal planes of protonated titanate in a monoclinic lattice (C2 / m), respectively, indicating that HTNTs have relatively poor crystallinity. STNTs exhibit strong diffraction peaks at 2θ values of 22.6°, 32.5°, 40.1°, 46.7°, 57.5°, 67.7°, and 77.1°, corresponding to the (100), (110), (111), (200), (211), (220), and (310) crystal planes of cubic SrTiO3, respectively.
[0041] Figure 5 The image shows the performance of the STNTs, STNPs, and STNRs photocatalysts prepared in this embodiment in reducing CO2 to CO under visible light irradiation. The specific steps included: weighing 10 mg of photocatalyst into a photoreactor, adding 4 mL of H2O, 2 mL of lactic acid, and 6 mL of acetonitrile, and ultrasonically dispersing the mixture. The mixture was then placed on a gas chromatography apparatus, evacuated, and CO2 was introduced to 80 kPa. The circulating cooling water was set to 10°C, and a 300 W xenon lamp was turned on. Samples were injected every 1 hour, and data were recorded. The results showed that STNTs exhibited superior photocatalytic reduction performance, reaching 239.35 μmol g / L. −1 h −1 .
[0042] Figure 6 The graph shows the change in CO production from STNTs-catalyzed CO2 reduction over time. No products were formed in the dark, but CH4 and CO were generated after illumination, demonstrating that STNTs are relatively sensitive photocatalysts. Simultaneously, we performed CO selectivity calculations, such as... Figure 6 The selectivity shown is 97.2%.
[0043] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.
Claims
1. A method for preparing strontium titanate with a special morphology, characterized in that, Includes the following steps: Step 1) Weigh the set amount of rutile powder and dissolve it in NaOH solution. After ultrasonic treatment for a set time, transfer the resulting mixture to a high-pressure reactor for high-temperature reaction. After natural cooling, acid washing, centrifugation, and freeze drying, protonated titanate nanotubes (HTNT) are obtained. Step 2) Weigh the set amount of protonated titanate nanotubes (HTNT) obtained in Step 1) and disperse them in an aqueous solution. While stirring continuously, add SrCl2·6H2O and NaOH. Transfer the resulting mixture to a high-pressure reactor for high-temperature reaction. After natural cooling, wash and dry to obtain strontium titanate nanotubes (STNT), strontium titanate nanoparticles (STNP), and nanorods (STNR).
2. The method for preparing strontium titanate with a special morphology according to claim 1, characterized in that, In step 1), the amount of rutile powder is 1-3 g, the concentration of NaOH solution is 10 M, and the amount used is 80-90 mL.
3. A method for preparing strontium titanate with a special morphology according to claim 1 or 2, characterized in that, In step 1), the ultrasonic treatment time is 30-60 min, the heating rate in the high-pressure reactor is 2-5 °C / min, the holding time is 24-48 h, and the reaction temperature is 120-150 °C.
4. A method for preparing strontium titanate with a special morphology according to claim 1 or 2, characterized in that, In step 1), the pickling process involves washing with water and hydrochloric acid 3-5 times each.
5. A method for preparing strontium titanate with a special morphology according to claim 1 or 2, characterized in that, In step 2), the amount of protonated titanate nanotubes (HTNT) is 0.5-2 g, and the amount of pure water in the aqueous solution is 50-70 mL.
6. A method for preparing strontium titanate with a special morphology according to claim 1 or 2, characterized in that, In step 2), the amount of SrCl2·6H2O added is 0.334-13.36 g, and the amount of NaOH is 2-4 g.
7. A method for preparing strontium titanate with a special morphology according to claim 1 or 2, characterized in that, In step 2), the reaction temperature in the high-pressure reactor is 200-220℃, and the hydrothermal time is 0.5-12 h.
8. A method for preparing strontium titanate with a special morphology according to claim 1 or 2, characterized in that, In step 2), the washing process involves washing with water and ethanol 3-5 times each, and the drying process involves vacuum drying for 24-48 hours at a temperature of 80-100℃.