阅读说明：本技术 一种宽带水合碳酸氧铈微波吸收剂及其制备工艺与应用 (Broadband hydrated cerium oxycarbonate microwave absorbent, and preparation process and application thereof ) 是由 魏海燕 童国秀 汪欣欣 杨小芬 柯丽凤 季然 刘敏敏 吴文华 于 2021-01-28 设计创作，主要内容包括：本发明公开了一种宽带水合碳酸氧铈微波吸收剂的制备工艺,属于微波吸收技术领域。本发明以六水合硝酸铈和尿素为原料,采用一步微波水热反应,快速合成蝴蝶状水合碳酸氧铈。本发明通过一步微波水热法快速制备的水合碳酸氧铈微波吸收剂不仅形貌新颖、反应耗时短,还可以通过改变反应温度、碱源与铈源的物质的量之比、时间、浓度来调控产物的形貌及尺寸,并具有优异的微波吸收特性。本发明公开的可控制备工艺方法操作简单、耗时短且产品形貌新颖均一,克服了以往制备过程中反应条件苛刻、反应过程复杂、不环保、反应产物形貌单一等特点,具有良好的工业化应用潜力,可望进行市面推广与应用。(The invention discloses a preparation process of a wide-band hydrated cerium oxycarbonate microwave absorbent, belonging to the technical field of microwave absorption. The invention takes cerous nitrate hexahydrate and urea as raw materials, and adopts one-step microwave hydrothermal reaction to quickly synthesize butterfly-shaped cerous oxycarbonate hydrate. The hydrated cerium oxycarbonate microwave absorbent rapidly prepared by the one-step microwave hydrothermal method has novel appearance and short reaction time, can regulate and control the appearance and size of a product by changing the reaction temperature, the ratio of the amount of the alkali source to the amount of the cerium source, the time and the concentration, and has excellent microwave absorption characteristics. The controllable preparation process method disclosed by the invention is simple to operate, short in time consumption and novel and uniform in product appearance, overcomes the defects of harsh reaction conditions, complex reaction process, environmental pollution, single appearance of reaction products and the like in the conventional preparation process, has good industrial application potential, and is expected to be popularized and applied in the market.)

1. The broadband hydrated cerium oxycarbonate microwave absorbent is characterized in that the broadband hydrated cerium oxycarbonate microwave absorbent is a monodisperse microwave absorbent, the molecular composition of the broadband hydrated cerium oxycarbonate microwave absorbent is Ce, C, H and O, and the molecular formula of the product is Ce (CO)₃)₂O·H₂O; the wide-band hydrated cerium oxycarbonate microwave absorbent is prepared by adopting a rapid one-step microwave hydrothermal method, and the wide-band hydrated cerium oxycarbonate microwave absorbent is butterfly-shaped, has a long axis length of 6.33-48.49 mu m, a short axis widest part of 3.55-14.63 mu m and a thickness of 2.96-13.52 mu m.

2. The broadband hydrous cerium oxide carbonate microwave absorbent according to claim 1, wherein the broadband hydrous cerium oxide carbonate microwave absorbent has excellent microwave absorption characteristics, wherein the maximum effective bandwidth of-10 dB or less of reflectivity is 4.88 to 9.52GHz, and the maximum absorption is-31.07 to-47.35 dB; and the wide-band hydrated cerium oxycarbonate microwave absorbent is filled in the matrix by the mass fraction of 60%.

3. The preparation process of the wide-band hydrated cerium oxide carbonate microwave absorbent according to claim 1, wherein the wide-band hydrated cerium oxide carbonate microwave absorbent is prepared by a rapid one-step microwave hydrothermal method, and the process specifically comprises the following steps:

(1) adding an alkali source and a cerium source into deionized water according to a certain stoichiometric ratio, and stirring to obtain a uniformly mixed solution;

(2) transferring the solution to a microwave digestion tank with a polytetrafluoroethylene lining and double walls, putting the microwave digestion tank into a microwave digestion instrument, and performing microwave radiation reaction to obtain a crude product;

(3) and (3) centrifuging, washing and drying the crude product at constant temperature for multiple times to finally obtain the wide-band hydrated cerium oxycarbonate microwave absorbent.

4. The preparation process of the broad band hydrated cerium oxycarbonate microwave absorbent according to claim 3, wherein the stirring temperature in the step (1) is room temperature, and the stirring time is 20-30 min.

5. The process for preparing the broad band hydrated cerium oxycarbonate microwave absorbent according to claim 3 or 4, wherein the alkali source is urea, and the cerium source is cerium nitrate hexahydrate; and the ratio of the amounts of the alkali source and the cerium source is (1.5-3): 1; and the concentration of the cerium source is 0.030-0.120 mol/L.

6. The preparation process of the broad band hydrated cerium oxycarbonate microwave absorbent according to claim 3, wherein in the step (2), the reaction time of microwave radiation is 1-25 min, and the reaction temperature is 140-180 ℃.

7. The preparation process of the broad band hydrated cerium oxycarbonate microwave absorbent according to claim 3 or 6, wherein in the step (2), the microwave radiation reaction power is 10-40 kw, and the pressure is 6-15 atm.

8. The preparation process of the broadband hydrous cerium oxycarbonate microwave absorbent according to claim 3, wherein in the step (3), the centrifugation speed is 2000-4000 rpm, and the centrifugation time is 3-5 min; and the constant temperature drying temperature is 40 ℃.

9. The application of the wide-band hydrated cerium oxide carbonate microwave absorbent as defined in claim 1 or 2 or the wide-band hydrated cerium oxide carbonate microwave absorbent prepared by the process as defined in any one of claims 3 to 8 in microwave absorption.

Technical Field

The invention belongs to the technical field of microwave absorption, and relates to a novel efficient broadband microwave absorption material and a preparation process thereof; more particularly, relates to a simple and controllable process method for preparing a broad-band hydrated cerium oxycarbonate microwave absorbent.

Background

In recent years, rare earth materials have irreplaceable functions in military affairs, chemical engineering, glass materials, agriculture and other aspects. Because cerium has unique 4f electronic structure and lattice oxygen defect characteristics, the cerium element shows excellent oxygen storage and discharge capacity and charge exchange capacity, and cerium-based compounds and cerium-based composites are widely applied in the fields of three-way catalysts, fuel cells, photocatalysis, wastewater and waste gas treatment and the like, for example, Chinese invention patent (CN102344339B) discloses and introduces the application of a cerium-based catalyst in the preparation of halogenated methane by oxyhalogenation of methane; chinese patent (CN109607591B) discloses a preparation method of nano cerium dioxide material and its application in UV absorption. In the existing research, the valence of cerium in cerium-based compounds and cerium-based composites is mostly +3, +4, while the application research of +6 hydrated cerium oxycarbonate materials is rarely reported, and related reports are mostly limited to the hydrated cerium oxycarbonate as a precursor for preparing cerium oxide, and no report is found about the application of the hydrated cerium oxycarbonate in the technical field of microwave absorption.

Since morphology is an important factor in determining performance, realizing controllable preparation of novel morphology is undoubtedly a topic of profound significance in the technical field of materials. Currently, the shape of the common hydrous cerium oxycarbonate is mainly granular, for example, chinese patent document (CN109502627A) discloses a method for preparing uniform-granular nano hydrous cerium oxycarbonate, and few reports exist about controllable preparation methods of other hydrous cerium oxycarbonate with special shape. Meanwhile, the conventional method for preparing the hydrated cerium oxycarbonate mainly comprises the following steps: the method comprises the steps of uniform precipitation, precipitation-molten salt method, micro-emulsion method, ion exchange-hydrogen peroxide oxidation method, double-liquid ultrasonic atomization method, combustion method, hydrothermal method and the like, and the method often has the problems of large equipment, long flow, large concentration gradient, unchangeable equipment parameters and the like.

Therefore, how to develop a hydrated cerium oxycarbonate material which has simple and convenient process, easy industrialization, controllable appearance and size and better microwave absorption performance has higher research value in the field.

Disclosure of Invention

In view of the above, the present invention provides a method for preparing a broad-band hydrated cerium oxycarbonate microwave absorbent with simple process and controllable size, which aims at solving the problems in the prior art.

In order to achieve the purpose, the technical scheme of the invention is as follows:

the wide-band hydrated cerium oxycarbonate microwave absorbent is characterized in that the wide-band hydrated cerium oxycarbonate microwave absorbent is a monodisperse hydrated cerium oxycarbonate microwave absorbent, the molecular components of the wide-band hydrated cerium oxycarbonate microwave absorbent are Ce, C, H and O, and the molecular formula of the product is Ce (CO)₃)₂O·H₂O; the wide-band hydrated cerium oxycarbonate microwave absorbent is prepared by adopting a rapid one-step microwave hydrothermal method, and the wide-band hydrated cerium oxycarbonate microwave absorbent is butterfly-shaped, has a long axis length of 6.33-48.49 mu m, a short axis widest part of 3.55-14.63 mu m and a thickness of 2.96-13.52 mu m.

Preferably, the broadband hydrated cerium oxycarbonate microwave absorbent has excellent microwave absorption characteristics, wherein the maximum effective bandwidth of the reflectivity less than or equal to-10 dB is 4.88-9.52 GHz, and the maximum absorption is-31.07-47.35 dB; and the wide-band hydrated cerium oxycarbonate microwave absorbent is filled in the matrix by the mass fraction of 60%.

The invention adopts a one-step microwave hydrothermal method to rapidly prepare the wide-band hydrated cerium oxygen carbonate microwave absorbent, has great innovation in morphology compared with the existing method, initiates the application of the hydrated cerium oxygen carbonate in wave absorption, has simple steps, short period, no need of depending on a template, rapid operation and low requirement on instrument precision, and has great advantages.

The wide-band hydrated cerium oxycarbonate microwave absorbent disclosed by the invention is prepared by a rapid one-step microwave hydrothermal method, so that the wide-band hydrated cerium oxycarbonate microwave absorbent has the advantages of simple and convenient process, short production period, good repeatability and large-scale production; the hydrated cerium oxycarbonate microwave absorbent prepared by the method has the excellent characteristics of novel structure, good dispersibility and uniformity, adjustable size and shape, good wave-absorbing performance and the like.

Exemplarily, referring to the attached drawings of the relevant specification, the invention respectively observes the phase and morphology of the hydrated cerium oxycarbonate micropowder prepared by the method through XRD and SEM. And filling the cerium oxycarbonate micro powder in a paraffin base by a mass fraction of 60%, wherein the effective bandwidth of the reflectivity less than or equal to-10 dB is 4.88-9.52 GHz, and the maximum reflection loss is-31.07-47.35 dB.

The invention also aims to provide a preparation method of the butterfly-shaped hydrated cerium oxycarbonate, which is green, environment-friendly and suitable for industrial production.

In order to achieve the purpose, the invention adopts the following technical scheme:

a preparation process of a wide-band hydrated cerium oxycarbonate microwave absorbent adopts a rapid one-step microwave hydrothermal method for preparation, and the process specifically comprises the following steps:

(1) adding an alkali source and a cerium source into deionized water according to a certain stoichiometric ratio, and stirring to obtain a uniformly mixed solution;

(2) transferring the solution to a microwave digestion tank with a polytetrafluoroethylene lining and double walls, putting the microwave digestion tank into a microwave digestion instrument, and performing microwave radiation reaction to obtain a crude product;

(3) and (3) centrifuging, washing and drying the crude product at constant temperature for multiple times to finally obtain the wide-band hydrated cerium oxycarbonate microwave absorbent.

By adopting the technical scheme, the invention has the following beneficial effects:

the preparation method disclosed by the invention has the advantages of simple production equipment, simplicity and convenience in operation, short production period, greenness and environmental friendliness, and is suitable for industrial mass production.

Preferably, the stirring temperature in the step (1) is room temperature, and the stirring time is 20-30 min.

Preferably, the alkali source is urea, and the cerium source is cerium nitrate hexahydrate; and the ratio of the amounts of the alkali source and the cerium source is (1.5-3): 1; and the concentration of the cerium source is 0.030-0.120 mol/L.

Preferably, in the step (2), the microwave radiation reaction time is 1-25 min, and the reaction temperature is 140-180 ℃.

Preferably, in the step (2), the microwave radiation reaction power is 10-40 kw, and the pressure is 6-15 atm.

Preferably, in the step (3), the centrifugation speed is 2000-4000 rpm, and the centrifugation time is 3-5 min; and the constant temperature drying temperature is 40 ℃.

In addition, the invention also claims the application of the broadband hydrated cerium oxycarbonate microwave absorbent in microwave absorption.

And in some application scenes, the wide-band hydrated cerium oxycarbonate microwave absorbent can be used as a precursor of cerium oxide micropowder to prepare the cerium oxide micropowder with a special morphology.

According to the technical scheme, compared with the prior art, the invention provides the broad-band hydrated cerium oxycarbonate microwave absorbent, and the preparation process and the application thereof, and the broad-band hydrated cerium oxycarbonate microwave absorbent has the following excellent effects:

1) the hydrated cerium oxycarbonate prepared by the rapid one-step microwave hydrothermal method has novel appearance and short reaction time, and the appearance and the size of a product can be regulated and controlled by changing the reaction temperature, the ratio of the amount of the alkaline source to the amount of the cerium source, the time and the concentration, so that the prepared broadband hydrated cerium oxycarbonate microwave absorbent has butterfly-shaped appearance.

2) The invention discloses a preparation process of a wide-band hydrated cerium oxycarbonate microwave absorbent, which is convenient to operate, green and environment-friendly, has low requirement on instrument precision and has good industrial application potential.

3) The invention discloses a wide-band hydrated cerium oxycarbonate microwave absorbent which has wide application prospect in the fields of electrode materials, electrocatalysis, surface enhanced Raman spectroscopy, microwave absorption and shielding, photoelectric conversion or gas sensitivity.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

Fig. 1 to 2 show the phase and morphology of the product obtained in example 1 of the present invention under XRD and scanning electron microscope, respectively.

FIG. 3 shows the morphology of the product obtained in example 2 of the present invention measured under a scanning electron microscope.

FIG. 4 is a reflectance curve of the product obtained in example 2 of the present invention at a mass fraction of 60%.

FIG. 5 shows the morphology of the product obtained in example 3 of the present invention measured under a scanning electron microscope.

FIG. 6 shows the morphology of the product obtained in example 4 of the present invention measured under a scanning electron microscope.

FIG. 7 is a reflectance curve of a product obtained in example 4 of the present invention at a mass fraction of 60%.

FIG. 8 is the morphology of the product obtained in example 5 of the present invention measured under a scanning electron microscope.

FIG. 9 shows the morphology of the product obtained in example 6 of the present invention measured under a scanning electron microscope.

FIG. 10 shows the morphology of the product obtained in example 7 of the present invention measured under a scanning electron microscope.

FIG. 11 is a reflectance curve of a product obtained in example 7 of the present invention at a mass fraction of 60%.

FIG. 12 shows the morphology of the product obtained in example 8 of the present invention measured under a scanning electron microscope.

FIG. 13 shows the morphology of the product obtained in example 9 of the present invention measured under a scanning electron microscope.

FIG. 14 shows the morphology of the product obtained in example 10 of the present invention measured under a scanning electron microscope.

FIG. 15 shows the morphology of the product obtained in experiment 1 according to the present invention measured under a scanning electron microscope.

FIG. 16 shows the morphology of the product obtained in experiment 2 of the present invention measured under a scanning electron microscope.

FIG. 17 shows the morphology of the product obtained in experiment 3 according to the present invention measured under a scanning electron microscope.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The embodiment of the invention discloses a broadband hydrated cerium oxycarbonate microwave absorbent with simple and convenient process, controllable size and better wave absorption performance, and a preparation method and application thereof.

The present invention will be further specifically illustrated by the following examples for better understanding, but the present invention is not to be construed as being limited thereto, and certain insubstantial modifications and adaptations of the invention by those skilled in the art based on the foregoing disclosure are intended to be included within the scope of the invention.

The technical solution of the present invention will be further described with reference to the following specific examples.

Example 1:

a preparation process of a broad-band hydrated cerium oxycarbonate microwave absorbent specifically comprises the following steps:

0.7816g Ce (NO)₃·6H₂Dissolving 0.2703g of urea in 30mL of deionized water, and magnetically stirring for 20min at room temperature to form a colorless solution; then transferring the solution into a double-wall microwave digestion tank with a polytetrafluoroethylene lining, putting the tank into a microwave digestion instrument (WX-6000, Preekem), performing microwave radiation at 160 ℃ for 20min, naturally cooling to room temperature, alternately washing with absolute ethyl alcohol and deionized water, and drying in an oven at constant temperature of 40 ℃ to finally obtain the productThe microwave absorbent with hydrated cerium oxycarbonate.

The phases and the appearances of the obtained products measured under XRD and scanning electron microscope are respectively shown in figures 1-2. From the above analysis, the product was a uniform, monodisperse, butterfly-shaped hydrated cerium oxycarbonate. Wherein the long axis of the butterfly-shaped cerium oxycarbonate is about 9.73-15.64 μm, the widest part of the short axis is about 4.87-6.30 μm, and the thickness is about 3.11-5.47 μm.

Example 2:

the only difference compared to the preparation procedure disclosed in example 1 is that: the temperature of microwave radiation is 140 ℃, and the rest preparation steps and process parameters are the same.

The shapes of the obtained products measured under a scanning electron microscope are respectively shown in FIG. 3. The analysis shows that the product is hydrated cerium oxycarbonate which is mixed in a rod shape and a butterfly shape. Wherein the long axis of the butterfly-shaped hydrated cerium oxycarbonate is about 9.79-25.41 μm, the widest part of the short axis is about 4.68-8.16 μm, and the thickness is about 3.76-7.68 μm.

The heterogeneous material is filled in a paraffin base by 60 percent of mass fraction, and the measured reflectivity is shown in figure 4, wherein the effective bandwidth range of the reflectivity less than or equal to-10 dB is 6.48-9.52 GHz, and the maximum reflection loss is-47.35 dB.

Example 3:

the only difference compared to the preparation procedure disclosed in example 1 is that: the temperature of microwave radiation is 180 ℃, and the rest preparation steps and process parameters are the same.

The appearance of the obtained product measured under a scanning electron microscope is shown in FIG. 5. The analysis shows that the product is uniform and monodisperse multilayer butterfly-shaped hydrated cerium oxycarbonate. Wherein the size of the butterfly-shaped hydrated cerium oxycarbonate is about 11.65-31.66 μm in the major axis, about 8.64-11.36 μm in the widest part of the minor axis and about 4.07-8.46 μm in the thickness.

Example 4:

the only difference compared to the preparation procedure disclosed in example 1 is that: the quantity ratio of the urea added in the reaction to the cerous nitrate hexahydrate is 1.5:1, and the rest preparation steps and technological parameters are the same.

The appearance of the obtained product measured under a scanning electron microscope is shown in FIG. 6. The analysis shows that the product is uniform, monodisperse, butterfly-shaped hydrated cerium oxycarbonate which is reduced in level and larger in size compared with the product in example 3. Wherein the long axis of the butterfly-shaped hydrated cerium oxycarbonate is about 22.91-48.49 μm, the widest part of the short axis is about 8.28-14.63 μm, and the thickness is about 8.84-13.52 μm.

The heterogeneous material is filled in a paraffin base by 60% mass fraction, and the measured reflectivity is shown in figure 7, wherein the effective bandwidth range of the reflectivity less than or equal to-10 dB is 4.88-8.40 GHz, and the maximum reflection loss is-34.91 dB.

Example 5:

the only difference compared to the preparation procedure disclosed in example 1 is that: the quantity ratio of the urea added in the reaction to the cerous nitrate hexahydrate is 3:1, and the rest preparation steps and technological parameters are the same.

The appearance of the obtained product detected under a scanning electron microscope is shown in figure 8. The analysis shows that the product is uniform and monodisperse butterfly-shaped hydrated cerium oxycarbonate. Wherein the length of the long axis of the butterfly-shaped hydrated cerium oxycarbonate is about 6.69-23.46 μm, the widest part of the short axis is about 4.37-7.19 μm, and the thickness is about 4.74-6.96 μm.

Example 6:

compared to the preparation procedure disclosed in example 1, the only difference is that: the amount ratio of the urea substance added in the reaction is 1.2 times of that in the example 1, the temperature of microwave radiation is 180 ℃, the time of the microwave radiation is 1min, and the rest preparation steps and technological parameters are the same.

The shapes of the obtained products measured under a scanning electron microscope are respectively shown in FIG. 9. The analysis shows that the product is uniform butterfly-shaped hydrated cerium oxycarbonate with small size and no surface level differentiation. Wherein the long axis of the butterfly-shaped hydrated cerium oxycarbonate which does not have surface level differentiation is about 6.33-11.68 μm, the widest part of the short axis is 3.55-3.94 μm, and the thickness is about 2.96-3.57 μm.

Example 7:

compared to the preparation procedure disclosed in example 1, the only difference is that: the amount ratio of the urea substance added in the reaction is 1.2 times of that in example 1, the temperature of microwave radiation is 180 ℃, and the rest preparation steps and process parameters are the same.

The shapes of the obtained products measured under a scanning electron microscope are respectively shown in FIG. 10. The analysis shows that the product is butterfly-shaped hydrated cerium oxycarbonate with more surface level differentiation. Wherein the long axis of the butterfly-shaped hydrated cerium oxycarbonate with more surface level differentiation is about 17.85-23.98 μm, the widest part of the short axis is about 6.50-10.23 μm, and the thickness is about 3.89-6.30 μm.

The heterogeneous material is filled in a paraffin base by 60% mass fraction, and the measured reflectivity is shown in figure 11, wherein the effective bandwidth range of the reflectivity less than or equal to-10 dB is 6.16-9.20 GHz, and the maximum reflection loss is-31.07 dB.

Example 8:

compared to the preparation procedure disclosed in example 1, the only difference is that: the amount ratio of the urea substance added in the reaction is 1.2 times of that in the example 1, the temperature of microwave radiation is 180 ℃, the time of microwave radiation is 25min, and the rest preparation steps and technological parameters are the same.

The shapes of the obtained products measured under a scanning electron microscope are respectively shown in FIG. 12. Analysis shows that the product is butterfly hydrated cerium oxycarbonate which is broken in inclusion.

Example 9:

compared to the preparation procedure disclosed in example 1, the only difference is that: the concentration of the added hexahydrated cerium nitrate in the reaction is 0.030mol/L, and the rest preparation steps and technological parameters are the same.

The shapes of the obtained products measured under a scanning electron microscope are respectively shown in FIG. 13. The analysis shows that the product is the hydrated cerium oxycarbonate in a shape of a broken butterfly.

Example 10:

compared to the preparation procedure disclosed in example 1, the only difference is that: the concentration of the added cerium nitrate hexahydrate in the reaction is 0.120mol/L, and the rest preparation steps and technological parameters are the same.

The shapes of the obtained products measured under a scanning electron microscope are respectively shown in FIG. 14. The analysis shows that the product is the most obviously differentiated butterfly-shaped hydrated cerium oxycarbonate.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The method disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the description of the method part.

The inventive content is not limited to the content of the above-mentioned embodiments, wherein combinations of one or several of the embodiments may also achieve the object of the invention.

To further verify the excellent effects of the present invention, the inventors also conducted the following experiments:

experiment 1:

0.7816g Ce (NO)₃·6H₂Dissolving 0.2703g of urea in 30mL of deionized water, and magnetically stirring for 20min at room temperature to form a colorless solution; and then transferring the solution to a double-wall microwave digestion tank with a polytetrafluoroethylene lining, putting the tank into a microwave digestion instrument (WX-6000, Preekem), performing microwave radiation at 100 ℃ for 20min, naturally cooling to room temperature, alternately washing with absolute ethyl alcohol and deionized water, and drying in an oven at constant temperature of 40 ℃ to finally obtain a shuttle-shaped product.

The morphology of the obtained product under a scanning electron microscope is shown in FIG. 15.

Experiment 2:

0.7816g Ce (NO)₃·6H₂Dissolving 0.2703g of urea in 30mL of deionized water, and magnetically stirring for 20min at room temperature to form a colorless solution; and then transferring the solution to a double-wall microwave digestion tank with a polytetrafluoroethylene lining, putting the tank into a microwave digestion instrument (WX-6000, Preekem), performing microwave radiation at 120 ℃ for 20min, naturally cooling to room temperature, alternately washing with absolute ethyl alcohol and deionized water, and drying in an oven at constant temperature of 40 ℃ to finally obtain a shuttle-shaped product.

The morphology of the obtained product under a scanning electron microscope is shown in FIG. 16.

Experiment 3:

0.7816g Ce (NO)₃·6H₂Dissolving O, 0.4324g urea in 30mL deionized water, and magnetically stirring at room temperature for 20min to form colorless solutionLiquid; and then transferring the solution to a double-wall microwave digestion tank with a polytetrafluoroethylene lining, putting the tank into a microwave digestion instrument (WX-6000, Preekem), performing microwave radiation at 160 ℃ for 20min, naturally cooling to room temperature, alternately washing with absolute ethyl alcohol and deionized water, and drying in an oven at constant temperature of 40 ℃ to finally obtain a rod-shaped product.

The morphology of the obtained product under a scanning electron microscope is shown in FIG. 17.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.