A method for rapidly synthesizing strontium tantalum pyrochlore based on microwave radiation

Abstract

The application discloses a method for rapidly synthesizing strontium tantalum pyrochlore based on microwave radiation and belongs to the field of preparation of pyrochlore structure tantalum-based oxide powder. The method comprises the following steps: (a) mixing SrCO3 and Ta2O5, and grinding uniformly to obtain a first mixed precursor M1; (b) adding a fluxing agent SrCl2.6H2O to the first mixed precursor M1, and mixing and grinding to obtain a second mixed precursor M2; (c) placing the second mixed precursor M2 in a quartz crucible with a cover, and burying the lower end of the crucible in a corundum crucible filled with graphite powder, and placing the crucible in a microwave oven, and reacting for 3-30 min, and naturally cooling after the reaction is completed, and taking out the product, and grinding, washing with water and drying to obtain strontium tantalum pyrochlore. The method for rapidly synthesizing strontium tantalum pyrochlore based on microwave radiation can overcome the problems of long synthesis period, high energy consumption, complex process and high cost of raw materials in the prior art.

Description

Technical Field

[0001] This invention belongs to the field of preparation of tantalum-based oxide powder with pyrochlore structure, specifically, it relates to a method for rapid synthesis of strontium-tantalum pyrochlore based on microwave radiation. Background Technology

[0002] Pyrochlore oxides, as an important class of inorganic functional materials, have the general chemical formula A₂B₂O₇ (where A and B are metal ions). By extensively substituting elements at the A and B sites, these materials can exhibit excellent high-temperature stability, good chemical stability, and diverse physicochemical properties, such as magnetic, optical, and dielectric properties, and have therefore received continuous attention in recent decades.

[0003] Strontium-tantalum pyrochlore (Sr2Ta2O7) is a typical representative of pyrochlore structural materials and has shown potential application value in many fields such as photocatalysis, electrocatalysis, luminescent materials, dielectrics and piezoelectrics (see patents and literature: CN119461475A; CN106902804A; CN111394099A; Ferroelectrics, 1995, 168(1), 161-167; J. Phys. Chem. C 2022, 126, 6556-6563; Journal of Catalysis, 2020, 389, 556-565).

[0004] However, the current methods for synthesizing strontium-tantalum pyrochlore still have a series of significant problems: High-temperature solid-state method: Using SrCO3 and Ta2O5 as raw materials, annealing is required at extremely high temperatures (e.g., 1643℃) for extremely long periods (e.g., 200 hours), resulting in high energy consumption and long cycle time (J. Phys. Chem. B2000, 104, 3, 571-575). Solid-state methods with added fluxes (such as KCl, NaCl, SrCl2, etc.): While these methods can reduce reaction temperature and time to some extent, they still rely on high-temperature equipment and require a subsequent water washing step (CN106902804A; CrystEngComm, 2013, 15, 8133-8138). Hydrothermal method: long reaction cycle (up to 7 days), high equipment requirements (CHINESE JOURNAL OF INORGANIC CHEMISTRY, 2009, 25, 2031-2035); Wet chemical methods (such as sol-gel method): The preparation of precursors is complicated, often requiring the use of air-sensitive and expensive raw materials (such as tantalum ethoxide and tantalum pentachloride), and annealing still takes several hours.

[0005] Therefore, in order to reduce the time and energy costs in the preparation process, it is of great significance to develop a rapid, low-energy-consumption, simple process and controllable raw material cost synthesis method for strontium-tantalum pyrochlore. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for rapid synthesis of strontium-tantalum pyrochlore based on microwave radiation.

[0007] The objective of this invention can be achieved through the following technical solutions: A method for rapid synthesis of strontium-tantalum pyrochlore based on microwave radiation includes the following steps: S1: SrCO3 and Ta2O5 are mixed and ground evenly to obtain the first mixed precursor M1; S2: Add flux SrCl2·6H2O to the first mixed precursor M1, mix and grind to obtain the second mixed precursor M2; S3: Place the second mixing precursor M2 in a quartz crucible with a lid, bury the lower end of the crucible in a corundum crucible containing graphite powder, and place it in a microwave oven for microwave radiation; S4: After the reaction is complete, the product is naturally cooled, ground, washed with water, and dried to obtain strontium tantalum pyrochlore.

[0008] The optimized process parameters for microwave radiation are: frequency of 2.45 GHz, power of 800-1000 W, and time of 3-30 min.

[0009] Ideally, the microwave radiation is delivered using a household microwave oven.

[0010] Ideally, the mass ratio of SrCl2·6H2O to the first mixed precursor M1 is (1-5):1.

[0011] Ideally, the molar ratio of SrCO3 to Ta2O5 is 2:1.

[0012] The beneficial effects of this invention: The method for rapid synthesis of strontium-tantalum pyrochlore based on microwave irradiation provided by this invention can significantly overcome the problems of long synthesis cycle, high energy consumption, complex process, and expensive raw materials in existing technologies. Compared with the traditional high-temperature solid-state method that requires annealing at 1643℃ for 200 hours, this invention only requires a reaction time of a few minutes to half an hour under microwave irradiation to complete the synthesis, greatly shortening the reaction time and reducing heat energy consumption. At the same time, this invention directly uses SrCO3 and Ta2O5, which are stable in air, as raw materials, eliminating the need for expensive tantalum ethoxide or tantalum pentachloride, which are sensitive to moisture and air, thus reducing raw material costs and storage requirements from the source, simplifying the precursor preparation process, and avoiding the complex sol-gel process in wet chemical methods.

[0013] Furthermore, this method uses a common household microwave oven as the heating device, replacing expensive dedicated high-temperature furnaces or microwave synthesizers, significantly reducing equipment investment and experimental barriers, which is conducive to the promotion and application of the method. Ultimately, this method can obtain strontium-tantalum pyrochlore products with good crystallinity and high purity in a very short time, providing an efficient, economical, and convenient preparation route for its subsequent application research in functional materials fields such as photocatalysis and electrocatalysis. Attached Figure Description

[0014] The invention will now be further described with reference to the accompanying drawings.

[0015] Figure 1 This is a schematic diagram of the reaction apparatus and raw material placement method according to an embodiment of the present invention; Figure 2 This is a flowchart illustrating the preparation process of Sr2Ta2O7 according to an embodiment of the present invention. Figure 3 The X-ray diffraction pattern of Sr2Ta2O7 obtained in an embodiment of the present invention; Figure 4 This is a scanning electron microscope image of Sr2Ta2O7 obtained in an embodiment of the present invention. Detailed Implementation

[0016] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0017] This invention provides a method for rapid synthesis of strontium-tantalum pyrochlore based on microwave radiation, the overall process flow of which is as follows: Figure 2 As shown, the schematic diagram of the reaction apparatus involved is as follows: Figure 1 As shown.

[0018] Figure 1 The device includes a household microwave oven 1, a porous heat-resistant insulation plate 2 placed in 1, a corundum crucible 3 containing graphite powder 4 placed on the porous heat-resistant insulation plate 2, and the lower end of a quartz crucible 5 containing reaction raw materials with a lid 6 buried in the graphite powder 4.

[0019] The present invention will be specifically described below through an embodiment: Example 1: A method for rapid synthesis of strontium-tantalum pyrochlore based on microwave radiation, comprising the following steps: S1: Weigh and mix SrCO3 and Ta2O5 at a molar ratio of 2:1, and grind them evenly to obtain the first mixed precursor M1; S2: Add flux SrCl2·6H2O to the first mixed precursor M1, mix and grind to obtain the second mixed precursor M2; wherein, the mass ratio of SrCl2·6H2O to the first mixed precursor M1 is 1:1; S3: Place the second mixed precursor M2 in a quartz crucible 5 with a lid 6 and gently tap it. Prepare an alumina crucible 3 and put an appropriate amount of graphite powder 4 into it. Bury the lower half of the quartz crucible containing M2 into the graphite powder to ensure that it is fully surrounded by the graphite powder. Place this alumina crucible on the porous heat-resistant insulation plate 2 inside the household microwave oven 1 and react for 3 minutes at a frequency of 2.45 GHz and a power of 800 W. S4: After the reaction is complete, the product is naturally cooled, ground, washed with water, and dried to obtain strontium tantalum pyrochlore (Sr2Ta2O7).

[0020] The product was analyzed by X-ray diffraction (XRD), and the results are as follows: Figure 3 As shown, all diffraction peaks match the standard Sr2Ta2O7 card, with no impurity peaks, indicating successful synthesis of pure-phase Sr2Ta2O7. Scanning electron microscope (SEM) images ( Figure 4 The product is shown to be irregular polygonal particles with uniform size distribution.

[0021] In summary, this example, using only a household microwave oven, completed a reaction in just 10 minutes that would have required tens or even hundreds of hours at temperatures above 1400°C using traditional methods. This fully demonstrates the outstanding effect of this invention in significantly reducing reaction time and energy consumption. Furthermore, the entire process is simple, requiring no complex precursor preparation or expensive air-sensitive reagents.

[0022] In the description of this specification, references to terms such as "an embodiment," "example," and "specific example" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0023] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for rapid synthesis of strontium-tantalum pyrochlore based on microwave radiation, characterized in that... This includes the following steps: S1: SrCO3 and Ta2O5 are mixed and ground evenly to obtain the first mixed precursor M1; S2: Add flux SrCl2·6H2O to the first mixed precursor M1, mix and grind to obtain the second mixed precursor M2; S3: Place the second mixing precursor M2 in a quartz crucible with a lid, bury the lower end of the crucible in a corundum crucible containing graphite powder, and place it in a microwave oven for microwave radiation; S4: After the reaction is complete, the product is naturally cooled, ground, washed with water, and dried to obtain strontium tantalum pyrochlore.

2. The method for rapid synthesis of strontium-tantalum pyrochlore based on microwave radiation according to claim 1, characterized in that... The process parameters for microwave radiation are: frequency of 2.45 GHz, power of 800-1000 W, and time of 3-30 min.

3. The method for rapid synthesis of strontium-tantalum pyrochlore based on microwave radiation according to claim 1, characterized in that... The microwave radiation is performed using a household microwave oven.

4. The method for rapid synthesis of strontium-tantalum pyrochlore based on microwave radiation according to claim 1, characterized in that... The mass ratio of SrCl2·6H2O to the first mixed precursor M1 is 1-5:

1.

5. The method for rapid synthesis of strontium-tantalum pyrochlore based on microwave radiation according to claim 1, characterized in that... The molar ratio of SrCO3 to Ta2O5 is 2:1.

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