Tantalum-based multi-component high-entropy oxynitride nanopowder, method of making and use thereof

Abstract

The application discloses tantalum-based multi-component high-entropy oxynitride nanopowder and a preparation method and application thereof. The preparation method comprises the following steps: dissolving magnesium oxide powder, calcium carbonate powder, strontium carbonate powder, barium carbonate powder, europium sesquioxide powder, tantalum pentoxide powder and first urea in anhydrous ethanol, performing ball milling to obtain mixed slurry, drying the mixed slurry to obtain mixed precursor powder, calcining the mixed precursor powder under a protective atmosphere, cooling to room temperature, and then performing ammoniation by using second urea to obtain the tantalum-based multi-component high-entropy oxynitride nanopowder, wherein 0 < a, b, c, d, e < 1, and a + b + c + d + e = 1. The preparation method has the advantages of low cost, simple process, short time consumption and high product purity, and the prepared product has excellent photocatalytic water oxygen production performance.

Description

Technical Field

[0001] This invention relates to the field of high-performance ceramic material preparation technology, specifically to tantalum-based multi-component high-entropy oxynitride nanopowder, its preparation method, and its applications. Background Technology

[0002] High-entropy materials are a new type of multi-principal-element materials composed of multiple elements in equal or near-equal amounts. The concept was first independently proposed by scholars Yeh Chun-wei from Taiwan, Cantor from Oxford University, and Ranganathan from the Indian Institute of Science. High-entropy alloys (HEAs), born from the concept of high entropy, are solid solutions with a single crystal structure composed of five or more metallic elements in equal or near-equal amounts, each element comprising 5% to 35% of the total composition. Due to their thermodynamic high-entropy effect, kinetic slow diffusion effect, structural lattice distortion effect, and cocktail effect, they exhibit superior properties unmatched by many traditional materials, making them a major focus of materials research in recent years.

[0003] In recent years, researchers both domestically and internationally have extended the design concept of HEAs to the field of high-entropy ceramics (HECs), developing a series of novel ceramic materials such as high-entropy carbides, high-entropy nitrides, high-entropy oxides, high-entropy borides, high-entropy sulfides, and high-entropy silicides. High-entropy perovskite oxides are multi-component oxides with a single solid solution structure, composed of five or more oxides in equimolar or near-equimolar amounts. These include transition metal-based HEOs (TM-HEOs), rare earth-based HEOs (RE-HEOs), and mixed-based HEOs (TM-RE-HEOs). Since their inception, high-entropy oxide ceramic materials have exhibited a series of excellent properties. By introducing nitrogen atoms into the crystal structure of high-entropy perovskite ABO3 oxides, a series of high-entropy tantalum-based perovskite oxynitrides, ATa(O,N)3 (A=Sr, Ba, Eu), have been synthesized.

[0004] Based on the relationship between material structure, process, and performance, the preparation process is crucial for obtaining ideal microstructures and excellent comprehensive properties in rare earth perovskite oxynitride materials. Currently, the mainstream method for synthesizing rare earth perovskite oxynitride powders involves first synthesizing a composite oxide precursor containing multiple metal cations using processes such as solid-phase calcination, sol-gel, polyol co-precipitation, and hydrothermal methods. The second step involves ammoniation treatment in a flowing ammonia atmosphere at high temperature. However, the gas-solid reaction diffusion is slow during the second ammoniation step, often confining the reaction to the gas-solid contact surface. To improve the yield, the reaction must be stopped midway to grind the powder, significantly prolonging the preparation time. Therefore, further research is needed to explore more efficient preparation and optimize the process. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a tantalum-based multi-component high-entropy oxynitride nanopowder with low cost, simple process, high purity, short time consumption and excellent visible light photocatalytic oxygen production performance, as well as its preparation method and application.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution.

[0007] A method for preparing tantalum-based multi-component high-entropy oxynitride nanopowder includes the following steps: (1) Dissolve magnesium oxide powder, calcium carbonate powder, strontium carbonate powder, barium carbonate powder, europium trioxide powder, tantalum pentoxide powder and first urea in anhydrous ethanol and ball mill them to obtain a mixed slurry; (2) The mixed slurry obtained in step (1) is dried to obtain mixed precursor powder; (3) The mixed precursor powder obtained in step (2) is heated to 1200℃~1500℃ under a protective atmosphere for calcination at a heating rate of 50℃ / min~300℃ / min and a holding time of 1min~10min. Then it is cooled to room temperature to obtain the initial powder of tantalum-based multi-component high-entropy oxynitride nanoparticles. The initial powder of tantalum-based multi-component high-entropy oxynitride nanoparticles is aminated with a second urea in a protective atmosphere to obtain tantalum-based multi-component high-entropy oxynitride nanoparticles, denoted as (Mg a Ca b Sr c Ba d Eu e )Ta(O,N)3, where 0<a, b, c, d, e<1, and a+b+c+d+e=1.

[0008] In the preferred method for preparing the tantalum-based multi-component high-entropy oxynitride nanopowder, in step (1), the addition ratio of (magnesium oxide powder + calcium carbonate powder + strontium carbonate powder + barium carbonate powder + europium trioxide powder), tantalum pentoxide powder, first urea, and anhydrous ethanol is 0.9mol~1.0mol∶0.5mol∶2mol~6mol∶80mL~200mL.

[0009] In the preferred method for preparing the tantalum-based multi-component high-entropy oxynitride nanopowder, step (3) involves heating to 1300℃~1400℃ and holding for 1min~5min.

[0010] In the above-mentioned method for preparing tantalum-based multi-component high-entropy oxynitride nanopowder, preferably, in step (3), the protective atmosphere is one or more of nitrogen, helium and argon, and the protective atmosphere for calcination is consistent with the protective atmosphere for ammoniation.

[0011] In the preferred method for preparing the above-mentioned tantalum-based multi-component high-entropy oxynitride nanopowder, the ammoniation process in step (3) is as follows: a crucible is prepared, a partition layer is provided inside the crucible, and the partition layer is provided with pores. The partition layer divides the crucible into an upper chamber and a lower chamber. The initial powder of the tantalum-based multi-component high-entropy oxynitride nanopowder is placed in the upper chamber, and a second urea is placed in the lower chamber. The mass of the second urea is 1 to 5 times the mass of the initial powder of the tantalum-based multi-component high-entropy oxynitride nanopowder. The temperature is increased to 1100°C to 1400°C at 100°C / min to 500°C / min under a protective atmosphere and held for 5 min to 30 min. The ammonia gas generated by the second urea enters the upper chamber through the pores to ammoniate the initial powder of the tantalum-based multi-component high-entropy oxynitride nanopowder.

[0012] In the above-mentioned method for preparing tantalum-based multi-component high-entropy oxynitride nanopowder, preferably, during the ammoniation process, the mass of the second urea is 2 to 4 times the initial mass of the tantalum-based multi-component high-entropy oxynitride nanopowder, and the temperature is increased to 1200 to 1300°C at a rate of 100°C / min to 300°C / min, and held for 10 to 20 minutes.

[0013] In the above-mentioned method for preparing tantalum-based multi-component high-entropy oxynitride nanopowder, preferably, in step (1), the ball milling time is 2h to 24h; in step (2), the drying temperature is 30℃ to 120℃, and the drying time is 1h to 48h.

[0014] As a general technical concept, the present invention also provides a method for preparing tantalum-based multi-component high-entropy oxynitride nanopowder, as described above, resulting in tantalum-based multi-component high-entropy oxynitride nanopowder. The tantalum-based multi-component high-entropy oxynitride nanopowder is a tantalum-based multi-component high-entropy (Mg... a Ca b Sr c Ba d Eu e Ta(O,N)3 oxynitride nanopowder, wherein 0 < a, b, c, d, e < 1, and a + b + c + d + e = 1.

[0015] As a general technical concept, the present invention also provides an application of the above-mentioned tantalum-based multi-component high-entropy oxynitride nanopowder in the field of photocatalytic water oxygen production.

[0016] In the above applications, preferably, the photocatalysis is visible light photocatalysis.

[0017] Compared with the prior art, the advantages of the present invention are as follows: 1. This invention provides a method for preparing tantalum-based multi-component high-entropy oxynitride nanopowder, using MgO, CaCO3, SrCO3, BaCO3, Eu2O3, and Ta2O5 as raw materials, and inexpensive urea CO(NH2)2 as the nitrogen source, to prepare (MgO) nanopowder at a relatively low temperature. a Ca b Sr c Ba d Eu e Ta(O,N)3 oxynitrides have advantages over mainstream solid-state reaction methods, precursor methods, or hydrothermal methods, such as low cost, short processing time, simple operation, and high product purity.

[0018] 2. In preparing tantalum-based multi-component high-entropy oxynitride nanopowder, the present invention employs a rapid ammoniation method. The initially prepared tantalum-based multi-component high-entropy oxynitride nanopowder is ammonified using a crucible with a specific structure. During this process, the ammonia gas generated by urea increases the nitrogen content of the product and can also effectively remove residual carbon generated by incomplete decomposition of urea in the reaction mixture, resulting in higher product purity (above 96%).

[0019] 3. The present invention employs a relatively fast heating rate in both the calcination of the mixed precursor powder and the ammoniation process. This is because urea can decompose at relatively low temperatures. To avoid premature loss of nitrogen source, a faster heating rate is used to increase the degree of nitrification when the reaction system reaches the higher temperature for generating oxynitrides and the degree of ammoniation thereafter, thereby improving the purity of the final product.

[0020] 4. This invention provides a tantalum-based multi-component high-entropy oxynitride nanopowder and its application. The tantalum-based multi-component high-entropy oxynitride nanopowder is (Mg...a Ca b Sr c Ba d Eu e Ta(O,N)3, where 0 < a, b, c, d, e < 1, and a + b + c + d + e = 1, the five cations in this nanopowder are relatively uniformly distributed at the microscopic level, forming a pure phase. It can be applied to the field of photocatalytic water oxygen production. It shows extremely high yield in visible light photocatalytic water splitting oxygen production test, has excellent photocatalytic water oxygen production performance, and has broad application prospects. Attached Figure Description

[0021] Figure 1 Optical photographs and XRD patterns of tantalum-based multi-component high-entropy oxynitride nanopowder prepared in Example 1 of this invention.

[0022] Figure 2 This is a SEM image showing the microstructure of the tantalum-based multi-component high-entropy oxynitride nanopowder prepared in Example 1 of this invention. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but this does not limit the scope of protection of the present invention. All materials and instruments used in the following embodiments are commercially available.

[0024] Example 1 A method for preparing tantalum-based multi-component high-entropy oxynitride nanopowder according to the present invention includes the following steps: (1) Dissolve 0.52g (0.013mol) magnesium oxide powder, 1.31g (0.013mol) calcium carbonate powder, 1.93g (0.013mol) strontium carbonate powder, 2.57g (0.013mol) barium carbonate powder, 2.30g (0.0065mol) europium trioxide powder, 14.41g (0.0325mol) tantalum pentoxide powder and 19.57g (0.325mol) urea in 100mL of anhydrous ethanol and ball mill for 8h to obtain a mixed slurry; (2) The mixed slurry obtained in step (1) is dried at a temperature of 100°C for 12 hours to obtain mixed precursor powder. (3) The mixed precursor powder obtained in step (2) is placed in the first crucible (a conventional crucible) and calcined in a nitrogen atmosphere at 1400°C. The heating rate is 100°C / min, and the holding time is 1min. Then, it is cooled to room temperature with the furnace to obtain the initial powder of tantalum-based multi-component high-entropy oxygen nitride nanoparticles. Then, the initial powder of tantalum-based multi-component high-entropy oxygen nitride nanoparticles is placed in the second crucible. The second crucible is provided with a partition layer with pores. The partition layer divides the crucible into an upper chamber and a lower chamber. The tantalum-based multi-component high-entropy oxygen nitride nanoparticles are then placed in the second crucible. The initial nitride nanoparticles were placed in the upper chamber, and a second urea, with a mass 2.5 times that of the initial tantalum-based multi-component high-entropy oxynitride nanoparticles, was placed in the lower chamber. Under nitrogen protection, the temperature was rapidly increased to 1300℃ at 300℃ / min using a discharge plasma device and held for 10 min. The ammonia gas generated by the urea entered the upper chamber through the pores of the separator layer for rapid ammoniation, yielding high-purity (98.73%) tantalum-based multi-component high-entropy oxynitride nanoparticles, specifically tantalum-based five-component high-entropy oxynitride nanoparticles (Mg... 0.2 Ca 0.2 Sr 0.2 Ba 0.2 Eu 0.2 )Ta(O,N)3.

[0025] The phase composition and microstructure of the tantalum-based multi-component high-entropy oxynitride nanopowder in this embodiment are as follows: Figure 1 and Figure 2 As shown: by Figure 1 It can be seen that its phase is almost a pure phase (Mg). 0.2 Ca 0.2 Sr 0.2 Ba 0.2 Eu 0.2 Ta(O,N)3 is black in color and has a uniform morphology and size, with a grain size of about 50nm to 200nm.

[0026] The tantalum-based multi-component high-entropy oxynitride nanoparticles prepared in this embodiment were applied to photocatalytic water oxygen production. Water was decomposed under visible light to produce oxygen. The test results are shown in Table 1. The (Mg) nanoparticles prepared in this embodiment... 0.2 Ca 0.2 Sr 0.2 Ba 0.2 Eu 0.2 Ta(O,N)3 oxynitride has an extremely high oxygen production rate.

[0027] Comparative Example 1 The preparation process of a barium tantalum oxynitride nanopowder is as follows: (1) Dissolve 5g of barium carbonate powder, 5.5g of tantalum pentoxide powder and 7.5g of urea in anhydrous ethanol and ball mill them to obtain a mixed slurry; (2) Dry the mixed slurry thoroughly to obtain mixed precursor powder; (3) The mixed precursor powder was placed in a crucible and calcined at 980°C under a protective atmosphere to obtain BaTaO2N oxynitride nanoparticles. The barium tantalum oxynitride in Comparative Example 1 is a common tantalum-based oxynitride.

[0028] The oxygen production rate of the BaTaO2N oxynitride nanopowder prepared in this comparative example for oxygen production by water splitting under visible light catalysis was only 40.63 μmol·g. -1 ·h -1 The oxygen production rate of this comparative product under visible light photocatalysis was significantly lower than that of Example 1. This is because high-entropy materials exhibit thermodynamic high-entropy effects, kinetic slow diffusion effects, structural lattice distortion effects, and performance cocktail effects, demonstrating superior properties that are unmatched by many traditional materials.

[0029] Table 1. Photocatalytic oxygen production rates of products from Example 1 and Comparative Example 1

[0030] Example 2 A method for preparing tantalum-based multi-component high-entropy oxynitride nanopowder according to the present invention includes the following steps: (1) Dissolve 0.47g (0.0117mol) magnesium oxide powder, 1.76g (0.0176mol) calcium carbonate powder, 5.19g (0.0352mol) strontium carbonate powder, 6.94g (0.0352mol) barium carbonate powder, 3.09g (0.0087mol) europium trioxide powder, 25.91g (0.0587mol) tantalum pentoxide powder and 35.19g (0.587mol) urea in 100mL of anhydrous ethanol and ball mill for 8h to obtain a mixed slurry; (2) The mixed slurry obtained in step (1) is dried at a temperature of 100°C for 12 hours to obtain mixed precursor powder. (3) The mixed precursor powder obtained in step (2) is placed in a first crucible (a conventional crucible) and calcined at 1400°C in a nitrogen atmosphere at a heating rate of 100°C / min for 1 min. Then, it is cooled to room temperature with the furnace to obtain the initial powder of tantalum-based multi-component high-entropy oxynitride nanoparticles. The initial powder of tantalum-based multi-component high-entropy oxynitride nanoparticles is then placed in a second crucible for rapid ammoniation. The structure of the second crucible and the ammoniation process are the same as in Example 1 to obtain high-purity (96.31%) tantalum-based multi-component high-entropy oxynitride nanoparticles, specifically tantalum-based five-component high-entropy oxynitride nanoparticles (Mg 0.1 Ca 0.15 Sr0.3 Ba 0.3 Eu 0.15 )Ta(O,N)3.

[0031] Example 3 A method for preparing tantalum-based multi-component high-entropy oxynitride nanopowder according to the present invention includes the following steps: (1) Dissolve 0.52g (0.0130mol) magnesium oxide powder, 1.87g (0.0187mol) calcium carbonate powder, 5.20g (0.0352mol) strontium carbonate powder, 6.94g (0.0352mol) barium carbonate powder, 2.68g (0.00763mol) europium trioxide powder, 25.91g (0.0587mol) tantalum pentoxide powder and 35.19g (0.587mol) urea in 100mL of anhydrous ethanol and ball mill for 8h to obtain a mixed slurry; (2) The mixed slurry obtained in step (1) is dried at a temperature of 100°C for 12 hours to obtain mixed precursor powder. (3) The mixed precursor powder obtained in step (2) is placed in the first crucible and calcined at 1400°C in a nitrogen atmosphere at a heating rate of 100°C / min for 1 min. Then, it is cooled to room temperature in the furnace to obtain the initial powder of tantalum-based multi-component high-entropy oxynitride nanoparticles. The initial powder of tantalum-based multi-component high-entropy oxynitride nanoparticles is then placed in the second crucible for ammoniation. The structure of the second crucible and the ammoniation process are the same as in Example 1 to obtain high-purity (97.83%) tantalum-based multi-component high-entropy oxynitride nanoparticles, specifically tantalum-based five-component high-entropy oxynitride nanoparticles (Mg 0.11 Ca 0.16 Sr 0.3 Ba 0.3 Eu 0.13 Ta(O,N)3 oxynitride nanopowder.

[0032] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the spirit and technical essence of the present invention. Therefore, any simple modifications, equivalent substitutions, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall still fall within the protection scope of the technical solutions of the present invention.

Claims

1. A method for preparing tantalum-based multi-component high-entropy oxynitride nanopowder, characterized in that, Includes the following steps: (1) Dissolve magnesium oxide powder, calcium carbonate powder, strontium carbonate powder, barium carbonate powder, europium trioxide powder, tantalum pentoxide powder and first urea in anhydrous ethanol and ball mill them to obtain a mixed slurry; (2) The mixed slurry obtained in step (1) is dried to obtain mixed precursor powder; (3) The mixed precursor powder obtained in step (2) is heated to 1300℃~1400℃ under a protective atmosphere for calcination at a heating rate of 100℃ / min~300℃ / min and a holding time of 1min~5min. Then it is cooled to room temperature to obtain the initial powder of tantalum-based multi-component high-entropy oxynitride nanopowder. The initial powder of tantalum-based multi-component high-entropy oxynitride nanopowder is aminated with a second urea in a protective atmosphere to obtain tantalum-based multi-component high-entropy oxynitride nanopowder, denoted as (Mg a Ca b Sr c Ba d Eu e Ta(O,N)3, where 0 < a, b, c, d, e < 1, and a + b + c + d + e = 1; during the ammoniation process, the mass of the second urea is 2 to 4 times the initial mass of the tantalum-based multi-component high-entropy oxynitride nanopowder, and the temperature is increased to 1200 to 1300℃ at a rate of 100℃ / min to 300℃ / min, and held for 10 to 20 minutes.

2. The method for preparing tantalum-based multi-component high-entropy oxynitride nanopowder according to claim 1, characterized in that, In step (1), the addition ratio of (magnesium oxide powder + calcium carbonate powder + strontium carbonate powder + barium carbonate powder + europium trioxide powder), tantalum pentoxide powder, first urea, and anhydrous ethanol is 0.9mol~1.0mol∶0.5mol∶2mol~6mol∶80mL~200mL.

3. The method for preparing tantalum-based multi-component high-entropy oxynitride nanopowder according to claim 1 or 2, characterized in that, In step (3), the protective atmosphere is one or more of nitrogen, helium and argon, and the protective atmosphere for calcination is consistent with the protective atmosphere for ammoniation.

4. The method for preparing tantalum-based multi-component high-entropy oxynitride nanopowder according to claim 1 or 2, characterized in that, In step (3), the ammoniation process is as follows: a crucible is prepared, and a partition layer is provided inside the crucible. The partition layer is provided with pores, and the partition layer divides the crucible into an upper chamber and a lower chamber. The initial powder of the tantalum-based multi-component high-entropy oxynitride nanopowder is placed in the upper chamber, and the second urea is placed in the lower chamber. The ammonia gas generated by the second urea enters the upper chamber through the pores to ammoniate the initial powder of the tantalum-based multi-component high-entropy oxynitride nanopowder.

5. The method for preparing tantalum-based multi-component high-entropy oxynitride nanopowder according to claim 1 or 2, characterized in that, In step (1), the ball milling time is 2h to 24h; in step (2), the drying temperature is 30℃ to 120℃, and the drying time is 1h to 48h.

6. Tantalum-based multi-component high-entropy oxynitride nanopowder prepared by a method according to any one of claims 1 to 5.

7. The application of tantalum-based multi-component high-entropy oxynitride nanopowder as described in claim 6 in the field of photocatalytic water oxygen production.

8. The application according to claim 7, characterized in that, The photocatalysis is visible light photocatalysis.

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