Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a low-dimensional layered yttrium oxide nanosheet and a preparation method thereof, and solves the problems of low yield and poor repeatability of the existing preparation method of the layered yttrium oxide nanosheet.
In order to achieve the purpose, the invention provides the following technical scheme:
a preparation method of low-dimensional layered yttrium oxide nanosheets comprises the following steps:
flatly spreading yttrium chloride hexahydrate, sending the yttrium chloride hexahydrate into a muffle furnace at 500-1000 ℃, preserving heat for 1-10 min, cooling the yttrium chloride hexahydrate along with the furnace, and taking out the yttrium chloride hexahydrate to obtain yttrium oxychloride crystals;
dissolving yttrium oxychloride crystals in a solvent, and performing centrifugal treatment to obtain yttrium oxide;
and annealing the yttrium chloride to obtain the low-dimensional layered yttrium oxide nanosheet.
Further, the beaker filled with the yttrium chloride hexahydrate is sent into a muffle furnace at 600 ℃ for heating for 2 min.
Further, dissolving the yttrium oxychloride crystal in a solvent, performing ultrasonic stirring for 10-20 min, and then performing centrifugal treatment at a centrifugal rate of 5000-15000 r/min.
Further, the time of ultrasonic stirring is 15min, and the centrifugation speed is 10000 r/min.
Further, the yttrium oxychloride crystal is dissolved in the solvent, three times of centrifugal treatment are needed, the solvent for the first two times of centrifugal treatment is deionized water, the absolute ethyl alcohol is used as the solvent for the last time, and the yttrium oxide is obtained by filtration after the centrifugal treatment.
Further, the solvent is deionized water or absolute ethyl alcohol, and the concentration of the absolute ethyl alcohol is 99.9%.
Further, annealing yttrium chloride to obtain the low-dimensional layered yttrium oxide nanosheet specifically comprises the following steps:
dispersing yttrium chloride into a beaker, sending the beaker into a muffle furnace at the temperature of 50-500 ℃ for annealing for 1-5 h, and cooling to obtain the low-dimensional layered yttrium oxide nanosheet.
Further, the beaker was charged with yttrium chloride and was annealed in a muffle furnace at 300 ℃ for 3 hours.
The invention also provides a low-dimensional layered yttrium oxide nanosheet prepared by the preparation method of the low-dimensional layered yttrium oxide nanosheet.
Compared with the prior art, the invention has at least the following beneficial effects:
the invention provides a preparation method of a low-dimensional layered yttrium oxide nanosheet. The method for rapid thermal treatment enables the raw materials to be rapidly decomposed and expanded to obtain an intermediate product with a layered structure, the test condition of the method is easy to achieve, the yield is high, the repeatability is good, the method has the advantages of being green and environment-friendly, and meanwhile, the prepared low-dimensional yttrium oxide nanosheet has high crystal quality; the low-dimensional layered yttrium oxide nanosheet is used as a rare earth oxide nanomaterial, and the controllable synthesis of the high-quality layered yttrium oxide nanosheet has profound significance in electronic devices.
And further, feeding the beaker filled with the yttrium chloride hexahydrate into a muffle furnace at 500-1000 ℃, and heating for 1-10 min to obtain yttrium oxychloride crystals, wherein when the heating temperature is lower than 500 ℃, crystal water contained in the yttrium chloride hexahydrate is not completely removed, and meanwhile, the chlorine content of the obtained intermediate is too high due to too high temperature, and the intermediate is not easy to remove in the later period. The rate of decomposing hydrogen chloride in the heating process is slowed down along with the increase of time, so that the hydrogen chloride volatilized out in the heating range of 500-1000 ℃ and the heating time of 1-10 min can not be absorbed by the intermediate (yttrium oxychloride) again, and the pure intermediate yttrium oxychloride can be obtained.
Further, the beaker filled with the yttrium chloride hexahydrate is sent into a muffle furnace at 600 ℃ for heating for 2min, so that hydrogen chloride can be prevented from being reabsorbed, and the extraction cleanliness of the yttrium oxychloride is improved.
Further, after dissolving the yttrium oxychloride crystals in the solvent and carrying out ultrasonic stirring for 10-20 min, carrying out centrifugal treatment at a centrifugal rate of 5000-15000 r/min, and completely dissolving the yttrium oxychloride crystals.
Furthermore, the ultrasonic stirring time is 15min, and the centrifugal speed is 10000r/min, so that the yttrium oxychloride achieves the optimal dissolution time and sedimentation rate.
Furthermore, the yttrium oxychloride crystals are dissolved in the solvent for three times of centrifugal treatment, wherein the solvent for the first two times of centrifugal treatment is deionized water, so that suspended particles can be more completely settled, and the absolute ethyl alcohol is used as the solvent for the last time, so that the agglomeration degree of settlement can be reduced, and the dispersion degree is higher.
Further, the beaker filled with the yttrium oxide is sent into a muffle furnace with the temperature of 50-500 ℃ for annealing for 1-5 h, and the agglomerated yttrium oxide can be decomposed into the layered yttrium oxide.
Furthermore, the high-quality layered yttrium oxide nanosheets can be obtained by loading yttrium oxide into the beaker, and feeding the yttrium oxide into a 300 ℃ muffle furnace for annealing for 3 hours.
The invention also provides a low-dimensional layered yttrium oxide nanosheet which has a good crystal structure, is free of impurity phases, has the number of layers from several to dozens, has a direct band gap structure and is 5.49eV, has high crystal quality and has profound significance in electronic devices.
Detailed Description
The invention is further described with reference to the following figures and detailed description.
As shown in fig. 1, the invention provides a preparation method of a low-dimensional layered yttrium oxide nanosheet, which comprises the following steps:
1) flatly paving 1g of yttrium chloride hexahydrate at the bottom of a high-temperature beaker, preheating a muffle furnace to 500-1000 ℃, clamping the beaker by using crucible tongs, sending the beaker into the muffle furnace at a certain temperature, rapidly closing a cavity door, keeping for 1-10 min, cooling to room temperature, and taking out to obtain an intermediate product;
the muffle furnace in the step 1) is heated to 600 ℃ in advance; the chamber door was quickly closed, held for 2min, then cooled to room temperature and removed.
The intermediate product obtained in the step 1) is yttrium oxychloride crystal.
2) Dissolving the obtained intermediate product in deionized water and absolute ethyl alcohol, wherein the concentration of the absolute ethyl alcohol is 99.9%, ultrasonically stirring for 10-20 min to fully dissolve yttrium oxychloride, then centrifuging three times at a speed of 5000-15000 r/min to reduce the agglomeration degree of sedimentation, adopting the deionized water for the first two times, using the absolute ethyl alcohol as a solvent for the last time, and filtering to obtain solid powder yttrium oxide;
the ultrasonic stirring time in the step 2) is 15 min.
The step 2) is performed with centrifugation three times at the speed of 10000 r/min.
3) Dispersing solid powder to the bottom of a beaker, clamping the beaker by using crucible tongs, sending the beaker into a muffle furnace at the temperature of 50-500 ℃ for annealing for 1-5 h to obtain layered yttrium oxide with good crystallinity, and naturally cooling to room temperature to finally obtain the low-dimensional layered yttrium oxide nanosheet.
And 3) clamping the beaker by using crucible tongs, and feeding the beaker into a muffle furnace at the temperature of 300 ℃ for annealing for 3 hours.
The number of layers of the low-dimensional layered yttrium oxide nanosheets prepared by the preparation method is several to dozens, the low-dimensional layered yttrium oxide nanosheets are free of impurity phases and have good crystal structures, and the low-dimensional layered yttrium oxide nanosheets have direct band gap structures of 5.49-5.8 eV.
Example 1
1) Flatly paving 1g of yttrium chloride hexahydrate at the bottom of a high-temperature beaker, preheating a muffle furnace to 400 ℃, clamping the beaker by using crucible tongs, feeding the beaker into the muffle furnace at a certain temperature, rapidly closing a cavity door, keeping for 2min, cooling to room temperature, and taking out to obtain an intermediate product, namely yttrium oxychloride;
2) dissolving the obtained intermediate product yttrium oxychloride in deionized water, ultrasonically stirring for 15min, centrifuging for three times at the speed of 10000r/min, adopting deionized water for the first two times, using absolute ethyl alcohol as a solvent for the last time, and filtering to obtain solid powder yttrium oxide;
3) dispersing solid powder yttrium oxide to the bottom of a beaker, clamping the beaker by using crucible tongs, sending the beaker into a muffle furnace at the temperature of 300 ℃ for annealing for 3 hours, and then naturally cooling to room temperature to finally obtain the low-dimensional layered yttrium oxide nanosheet.
Example 2
1) Paving 1g of yttrium chloride hexahydrate at the bottom of a high-temperature beaker, preheating a muffle furnace to 600 ℃, clamping the beaker by using crucible tongs, feeding the beaker into the muffle furnace at a certain temperature, rapidly closing a cavity door, keeping for 2min, cooling to room temperature, and taking out to obtain an intermediate product, namely yttrium oxychloride;
2) dissolving the obtained intermediate product yttrium oxychloride in a solvent, ultrasonically stirring for 15min, then centrifuging for three times at the speed of 10000r/min, adopting deionized water for the first two times, using absolute ethyl alcohol as the solvent for the last time, and filtering to obtain solid powder yttrium oxide;
3) dispersing solid powder yttrium oxide to the bottom of a beaker, clamping the beaker by using crucible tongs, sending the beaker into a muffle furnace at the temperature of 300 ℃ for annealing for 3 hours, and then naturally cooling to room temperature to finally obtain the low-dimensional layered yttrium oxide nanosheet.
Example 3
1) Flatly paving 1g of yttrium chloride hexahydrate at the bottom of a high-temperature beaker, preheating a muffle furnace to 700 ℃, clamping the beaker by using crucible tongs, sending the beaker into the muffle furnace at a certain temperature, rapidly closing a cavity door, keeping for 2min, cooling to room temperature, and taking out to obtain an intermediate product, namely yttrium oxychloride;
2) dissolving the obtained intermediate product yttrium oxychloride in a solvent, ultrasonically stirring for 15min, then centrifuging for three times at the speed of 10000r/min, adopting deionized water for the first two times, using absolute ethyl alcohol as the solvent for the last time, and filtering to obtain solid powder yttrium oxide;
3) dispersing solid powder yttrium oxide to the bottom of a beaker, clamping the beaker by using crucible tongs, sending the beaker into a muffle furnace at the temperature of 400 ℃ for annealing for 3 hours, and then naturally cooling to room temperature to finally obtain the low-dimensional layered yttrium oxide nanosheet.
Example 4
1) Flatly paving 1g of yttrium chloride hexahydrate at the bottom of a high-temperature beaker, preheating a muffle furnace to 800 ℃, clamping the beaker by using crucible tongs, feeding the beaker into the muffle furnace at a certain temperature, rapidly closing a cavity door, keeping for 2min, cooling to room temperature, and taking out to obtain an intermediate product, namely yttrium oxychloride;
2) dissolving the obtained intermediate product yttrium oxychloride in a solvent, ultrasonically stirring for 15min, then centrifuging three times at a speed of 9000r/min, adopting deionized water in the first two times, using absolute ethyl alcohol as the solvent in the last time, and filtering to obtain solid powder yttrium oxide;
3) dispersing solid powder yttrium oxide to the bottom of a beaker, clamping the beaker by using crucible tongs, sending the beaker into a muffle furnace at the temperature of 400 ℃ for annealing for 3 hours, and then naturally cooling to room temperature to finally obtain the low-dimensional layered yttrium oxide nanosheet.
Example 5
Paving 1g of yttrium chloride hexahydrate at the bottom of a high-temperature beaker, preheating a muffle furnace to 600 ℃, clamping the beaker by using crucible tongs, feeding the beaker into the muffle furnace at a certain temperature, rapidly closing a cavity door, keeping for 2min, cooling to room temperature, and taking out to obtain an intermediate product, namely yttrium oxychloride;
2) dissolving the obtained intermediate product yttrium oxychloride in a solvent, ultrasonically stirring for 15min, then centrifuging for three times at the speed of 10000r/min, adopting deionized water for the first two times, using absolute ethyl alcohol as the solvent for the last time, and filtering to obtain solid powder yttrium oxide;
3) dispersing solid powder yttrium oxide to the bottom of a beaker, clamping the beaker by using crucible tongs, sending the beaker into a muffle furnace at the temperature of 300 ℃ for annealing for 1h, and then naturally cooling to room temperature to finally obtain the low-dimensional layered yttrium oxide nanosheet.
As shown in FIG. 2, the microscopic morphology of the low-dimensional layered yttrium oxide nanosheets is obtained by a transmission electron microscope, and it can be seen that the yttrium oxide nanosheets with very thin thickness are illustrated in places with light white edge color, and the yttrium oxide nanosheets with darker color have more layers, so that the yttrium oxide nanosheets prepared by the method have higher density.
As shown in fig. 3, the morphology of the low-dimensional layered yttrium oxide nanosheets is further observed by using a scanning electron microscope, and it can be seen that the number of layers of the low-dimensional layered yttrium oxide nanosheets is from several to dozens, which further indicates that the quality of the yttrium oxide nanosheets obtained by annealing is high.
As shown in FIG. 4, XRD is adopted to test the crystal structures of the intermediate product and the low-dimensional layered yttrium oxide nanosheets, so that the intermediate product yttrium oxychloride has high purity and crystal quality, and meanwhile, the low-dimensional layered yttrium oxide nanosheets are free of impurity phases.
As shown in fig. 5, the crystal structure of the low-dimensional layered yttrium oxide nanosheet was observed using a high-resolution transmission electron microscope. It can be seen that it grows along the (222) crystal direction, and the XRD results mutually verify, indicating that the yttria obtained by the preparation method of the present invention is highly pure and free of impurity phases.
As shown in fig. 6, a and b, the optical properties of the low-dimensional layered yttrium oxide nanosheets were tested using absorption spectroscopy. The yttrium oxide nanosheet has a direct band gap structure of 5.49 eV.
In conclusion, the invention provides a preparation method for preparing low-dimensional layered yttrium oxide nanosheets. The method has the advantages of simple equipment requirement, easy achievement of experimental conditions, high yield, good repeatability and environmental protection, and the prepared low-dimensional yttrium oxide nanosheet has high crystal quality.
Finally, it should be noted that: the above-mentioned embodiments are only specific embodiments of the present invention, which are used for illustrating the technical solutions of the present invention and not for limiting the same, and the protection scope of the present invention is not limited thereto, although the present invention is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: any person skilled in the art can modify or easily conceive the technical solutions described in the foregoing embodiments or equivalent substitutes for some technical features within the technical scope of the present disclosure; such modifications, changes or substitutions do not depart from the spirit and scope of the embodiments of the present invention, and they should be construed as being included therein. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.