ZnSe2 inorganic compound material and preparation method thereof

Abstract

The invention discloses a ZnSe2 inorganic compound material and a preparation method thereof. The preparation method comprises the following steps: (1) grinding and mixing Zn powder and Se powder which are used for preparing an initial product ZnSe according to a molar ratio to obtain mixed powder; (2) performing vacuum tube sealing on the mixed powder, then sintering, and grinding the sintered ingot into powder to obtain an initial product ZnSe; (3) adding extra Se powder into the initial product ZnSe, grinding and mixing to obtain mixed powder; (4) performing cold pressing on the mixed powder to form a block, and then performing high-pressure sintering to obtain a block material; (5) grinding the block material into powder, and then carrying out high-pressure sintering according to the step (4); and (6) repeating the step (5) for one or more times. The used raw materials are rich in natural stock and non-toxic, the preparation cost is low, the preparation condition is low, the process is simple, the vacuum tube sealing technology is combined with the high-temperature and high-pressure technology, and the prepared ZnSe2 inorganic compound material is high in purity and large in size.

Description

Technical Field

[0001] This invention belongs to the field of materials synthesis technology, and particularly relates to a ZnSe2 inorganic compound material and its preparation method. Background Technology

[0002] In recent years, with the rapid development of computer technology and the continuous improvement of quantum chemical theory, theoretical calculations can predict new compounds that may exist but have not yet been experimentally discovered by simulating and analyzing the interactions between atoms and molecules. This method can greatly shorten the research and development cycle of new materials, reduce experimental costs, and guide experimental synthesis. Meanwhile, with the rapid development of high-temperature and high-pressure technology in recent years, high pressure is gradually becoming the fourth condition affecting compound synthesis after temperature, time, and composition. Under high pressure, the structure and atomic arrangement of the internal crystals of materials change, providing new directions for compound synthesis.

[0003] Transition metal compounds possess rich and diverse physical and chemical properties, exhibiting high application potential. The transition metal element zinc and the nonmetal element selenium are abundant in nature, being common inorganic mineral resources with advantages such as low price and plentiful yield. A 2019 study predicted that under high pressure, one Zn atom can bond with six Se atoms to form ZnSe2 material, exhibiting a pyrite-like structure. Under high pressure, this material has a low enthalpy of formation and excellent thermoelectric properties, possessing extremely low thermal conductivity and good electrical properties, making it a promising new thermoelectric material. Currently, there is no method for the mass synthesis of high-purity ZnSe2 material, significantly limiting the scope for further research, testing, and experimental exploration of this novel compound. Summary of the Invention

[0004] To address the current difficulties in preparing ZnSe2 inorganic compound materials, this invention provides a ZnSe2 inorganic compound material and its preparation method. The method involves first preparing a precursor ZnSe using Zn powder and Se powder, then mixing the precursor ZnSe with Se powder, and successfully synthesizing high-purity, large-size ZnSe2 inorganic compound materials using high-temperature and high-pressure technology. This overcomes the challenge of preparing high-purity, large-size ZnSe2 materials. The preparation method of this invention utilizes abundant and non-toxic natural raw materials, has low production costs, requires minimal preparation conditions, and involves a simple process, making it suitable for laboratory preparation and research.

[0005] The technical solution of the present invention is as follows:

[0006] This invention provides a method for preparing ZnSe2 inorganic compound materials, comprising the following steps:

[0007] (1) Grind and mix Zn powder and Se powder, which are used to prepare the primary product ZnSe, by molar ratio to obtain a mixed powder;

[0008] (2) The mixed powder obtained in step (1) is vacuum sealed in a tube and then sintered. The sintered ingot is then ground into powder to obtain the initial product ZnSe.

[0009] (3) Add additional Se powder to the initial product ZnSe in step (2), grind and mix to obtain a mixed powder;

[0010] (4) The mixed powder in step (3) is cold-pressed into a block and then sintered under high pressure to obtain the block material;

[0011] (5) Grind the bulk material obtained in step (4) into powder, and then perform high-pressure sintering according to step (4);

[0012] (6) Repeat step (5) once or more to obtain pure phase ZnSe2 material.

[0013] Furthermore, in step (1), the molar ratio of Zn powder and Se powder is 1:1, and they are ground and mixed in an Ar atmosphere.

[0014] Furthermore, the grinding time in step (1) is 10-30 minutes.

[0015] Furthermore, in step (2), the sintering temperature is 800-1200℃, the time is 12-24 hours, the heating rate is 3-6℃ / minute, and the furnace temperature is naturally cooled after sintering.

[0016] Preferably, in step (2), the sintering temperature is 1000℃, the time is 24 hours, the heating rate is 5℃ / minute, and the furnace temperature is naturally cooled after sintering.

[0017] Furthermore, the molar ratio of the initial product ZnSe and the additional Se powder in step (3) is 1:1-1.2.

[0018] Furthermore, the grinding time in step (3) is 30-50 minutes;

[0019] And / or, the pressure for cold pressing into a block in step (4) is 2-8 MPa.

[0020] Furthermore, the conditions for high-pressure sintering in step (4) are: sintering pressure of 4-7 GPa, sintering temperature and time of 500℃~800℃ for 1-5 hours or more, and finally natural cooling.

[0021] Further, the conditions for high-pressure sintering in step (4) are as follows: the sintering pressure is 4-7 GPa, first maintain at 600-800℃ for 30-60 minutes, the heating rate is 100-200℃ / minute, then cool down to 600℃ in 10-60 seconds and maintain for 30-60 minutes, then cool down to 500℃ in 30 minutes, and finally cool naturally.

[0022] Preferably, the conditions for high-pressure sintering in step (4) are as follows: the sintering pressure is 4 GPa, the temperature is first maintained at 800°C for 30 minutes, the heating rate is 200°C / minute, then the temperature is lowered to 600°C in 10 seconds and maintained for 30 minutes, then the temperature is lowered to 500°C in 30 minutes, and finally the temperature is allowed to cool naturally.

[0023] Furthermore, in step (6), step (5) is repeated 2-4 times.

[0024] This invention also provides ZnSe2 inorganic compound materials prepared by the aforementioned method.

[0025] Technical effects of the present invention:

[0026] The present invention provides a method for preparing ZnSe2 inorganic compound materials. First, a precursor ZnSe is prepared using Zn powder and Se powder. Then, the precursor ZnSe is mixed with Se powder, and high-temperature, high-pressure technology is used to successfully synthesize high-purity, large-size ZnSe2 inorganic compound materials, overcoming the problem of the difficulty in preparing high-purity, large-size ZnSe2 materials. The beneficial effects of this invention include at least one of the following:

[0027] 1. The raw material cost is low. The present invention mainly uses Zn powder and Se powder as raw materials, which are abundant and inexpensive.

[0028] 2. The preparation process is simple, the materials are readily and quickly synthesized, and no toxic or polluting substances are generated during the process, making it suitable for laboratory preparation and research.

[0029] 3. The prepared ZnSe2 material has high density, large size and high purity. X-ray diffraction analysis showed no impurity phases in the sample. It is the first large-sized high-purity ZnSe2 material synthesized to date. Attached Figure Description

[0030] Figure 1 X-ray diffraction patterns of ZnSe2 samples after four high-pressure sinterings at 4 GPa with ZnSe:Se = 1:1.105;

[0031] Figure 2 Scanning electron microscope images and energy dispersive spectroscopy atomic ratio diagrams of ZnSe2 samples after four high-pressure sinterings at 4 GPa with ZnSe:Se = 1:1.105.

[0032] Figure 3 This is a dimensionally annotated optical photograph of the high-purity, large-size ZnSe2 sample synthesized in Example 1;

[0033] Figure 4 X-ray diffraction patterns of ZnSe2 samples after four high-pressure sinterings at 4 GPa with ZnSe:Se = 1:1.11;

[0034] Figure 5 Scanning electron microscope images and energy dispersive spectroscopy atomic ratio diagrams of ZnSe:Se:1:1.11 samples after four high-pressure sinterings at 4 GPa;

[0035] Figure 6 This is a dimensionally annotated optical photograph of the high-purity, large-size ZnSe2 sample synthesized in Example 2. Detailed Implementation

[0036] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0037] The following is a detailed explanation of the specific implementation plan:

[0038] To obtain the X-ray diffraction pattern of the sample, the high-pressure sintered sample was polished and cut, and then X-ray diffracted using a Rigaku Smartlab SE, 451B-DE-SI-RYR X-ray diffractometer manufactured by Rigaku Corporation of Japan, using a Cu target. The composition of the samples was characterized. To obtain the energy dispersive spectroscopy (EDS) spectrum of the samples, the composition of the samples was characterized using a Zeiss Sigma 500 scanning electron microscope.

[0039] Example 1

[0040] A method for preparing ZnSe2 inorganic compound materials includes the following steps:

[0041] 1) Ingredients. Mix Zn powder and Se powder in a certain molar ratio and place them in an agate mortar. The raw materials are high-purity Zn powder and Se powder; the molar ratio of Zn powder (purity of 99.99%) to Se powder (purity of 99.999%) is 1:1.

[0042] 2) Mixing. Grind the raw materials in a glove box for 15 minutes.

[0043] 3) Vacuum sealing. Before vacuum sealing the raw material, the quartz tube usually needs to be cleaned and dried. After ultrasonic cleaning, the quartz tube is dried in a constant temperature oven. After deoxidation treatment, the dried quartz tube is placed in a vacuum glove box, and the powder ground in the previous step is poured into the quartz tube.

[0044] 4) Sealing and Sintering of the Tube. The sealed quartz tube was placed in a muffle furnace for sintering. The temperature was set at 1000℃ and maintained for 24 hours, with a heating rate of 5℃ / minute. After the experiment, the furnace was allowed to cool naturally.

[0045] 5) Grinding. The cast ingot after sealing and sintering is ground into powder to obtain the primary product powder ZnSe.

[0046] 6) Secondary mixing. The initial product powders ZnSe and Se powder are placed in an agate mortar at a molar ratio of 1:1.105 and ground for 40 minutes. After being mixed evenly, the mixture is placed in a mold and cold-pressed into blocks at a pressure of 4 MPa.

[0047] 7) Single-stage high-pressure sintering. The cold-pressed block is subjected to high-pressure sintering. The sintering pressure is 4 GPa, and the sintering temperature flow is as follows: first, hold at 800℃ for 30 minutes, with a heating rate of 200℃ / min, then cool down to 600℃ in 10 seconds and hold for 30 minutes, then cool down to 500℃ for another 30 minutes, and finally allow to cool naturally. This yields a single-stage sintered block material.

[0048] 8) Multiple high-pressure sintering. The block material sintered once is ground into powder in a mortar and then placed back into a mold and cold-pressed into a block. The cold-pressed block is then sintered again using the same high-pressure process as in step 7). This process is repeated three times to finally obtain a ZnSe2 block material with good density.

[0049] Figure 1 The X-ray diffraction pattern of the ZnSe2 sample after four high-pressure sinterings in Example 1 is compared with the theoretically predicted X-ray diffraction pattern (ZnSe2 - first-principles calculation prediction). It can be observed that after four high-pressure sinterings, a high-purity ZnSe2 sample with a purity of 99.0% can be obtained.

[0050] Figure 2 In Example 1, ZnSe:Se = 1:1.105, after four high-pressure sinterings at 4 GPa, the following are SEM images (a) and energy dispersive spectroscopy (EDS) atomic ratio diagrams (b). Figure (b) shows that the proportions of Zn atoms and Se atoms are 35.92% and 64.08%, respectively, close to 1:2, which is within the error range.

[0051] Figure 3The figures show the dimensions of the ZnSe2 sample obtained in Example 1. (a) and (b) are the top and side views of the sample, respectively. The ZnSe2 synthesized according to the steps described in Example 1 has a large size, with a diameter of 10.91 mm, a height of 6.00 mm, and a total volume of 560.91 mm². 3 .

[0052] Example 2

[0053] A method for preparing ZnSe2 inorganic compound materials includes the following steps:

[0054] 1) Ingredients. Mix Zn powder and Se powder in a certain molar ratio and place them in an agate mortar. The raw materials are high-purity Zn powder and Se powder; the molar ratio of Zn powder (purity of 99.99%) to Se powder (purity of 99.999%) is 1:1.

[0055] 2) Mixing. Grind the raw materials in a glove box for 15 minutes.

[0056] 3) Vacuum sealing. Before vacuum sealing the raw material, the quartz tube usually needs to be cleaned and dried. After ultrasonic cleaning, the quartz tube is dried in a constant temperature oven. After deoxidation treatment, the dried quartz tube is placed in a vacuum glove box, and the powder ground in the previous step is poured into the quartz tube.

[0057] 4) Sealing and Sintering of the Tube. The sealed quartz tube was placed in a muffle furnace for sintering. The temperature was set at 1000℃ and maintained for 24 hours, with a heating rate of 5℃ / minute. After the experiment, the furnace was allowed to cool naturally.

[0058] 5) Grinding. The cast ingot after sealing and sintering is ground into powder to obtain the primary product powder ZnSe.

[0059] 6) Secondary mixing. The initial product powders ZnSe and Se powder are placed in an agate mortar at a molar ratio of 1:1.11 and ground for 40 minutes. After being mixed evenly, the mixture is placed in a mold and cold-pressed into blocks at a pressure of 4 MPa.

[0060] 7) Single-stage high-pressure sintering. The cold-pressed block is subjected to high-pressure sintering. The sintering pressure is 4 GPa, and the sintering temperature process is as follows: first, hold at 800℃ for 1 hour, with a heating rate of 200℃ / min, then cool down to 500℃ for 1 hour, and finally allow to cool naturally. The resulting block material is obtained through single-stage sintering.

[0061] 8) Multiple high-pressure sintering. The block material sintered once is ground into powder in a mortar and then placed back into a mold and cold-pressed into a block. The cold-pressed block is then sintered again using the same high-pressure process as in step 7). This process is repeated three times to finally obtain a ZnSe2 block material with good density.

[0062] Figure 4 The X-ray diffraction pattern of the ZnSe2 sample after four high-pressure sinterings in Example 2 is compared with the theoretically predicted X-ray diffraction pattern (ZnSe2 - first-principles calculation prediction). It can be observed that after four high-pressure sinterings, a high-purity ZnSe2 sample with a purity of 98.7% can be obtained.

[0063] Figure 5 In Example 2, ZnSe:Se = 1:1.11, after four high-pressure sinterings at 4 GPa, the ZnSe2 sample is shown in SEM (a) and EDS (energy dispersive spectroscopy) atomic ratio test diagram (b). Figure (b) shows that the proportions of Zn atoms and Se atoms are 35.99% and 64.01%, respectively, which is close to 1:2 and within the error range.

[0064] Figure 6 The figures show the dimensions of the ZnSe2 sample obtained in Example 2. (a) and (b) are the top and side views of the sample, respectively. The ZnSe2 synthesized according to the steps described in Example 2 has a large size, with a diameter of 10.89 mm, a height of 5.35 mm, and a total volume of 498.31 mm². 3 .

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solutions of the present invention, as long as they do not depart from the technology and scope of the present invention, should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing ZnSe2 inorganic compound materials, characterized in that, Includes the following steps: (1) Grind and mix Zn powder and Se powder, which are used to prepare the primary product ZnSe, by molar ratio to obtain a mixed powder; (2) The mixed powder obtained in step (1) is vacuum sealed in a tube and then sintered. The sintered ingot is then ground into powder to obtain the initial product ZnSe. (3) Add additional Se powder to the initial product ZnSe in step (2), grind and mix to obtain a mixed powder; (4) The mixed powder in step (3) is cold-pressed into a block and then sintered under high pressure to obtain the block material; (5) Grind the bulk material obtained in step (4) into powder, and then perform high-pressure sintering according to step (4); (6) Repeat step (5) once or more to obtain pure phase ZnSe2 material.

2. The preparation method according to claim 1, characterized in that, In step (1), the molar ratio of Zn powder and Se powder is 1:1, and they are ground and mixed in an Ar atmosphere.

3. The preparation method according to claim 1, characterized in that, The grinding time in step (1) is 10-30 minutes.

4. The preparation method according to claim 1, characterized in that, The sintering temperature in step (2) is 800-1200℃, the time is 12-24 hours, the heating rate is 3-6℃ / minute, and the furnace temperature is naturally cooled after sintering. Preferably, in step (2), the sintering temperature is 1000℃, the time is 24 hours, the heating rate is 5℃ / minute, and the furnace temperature is naturally cooled after sintering.

5. The preparation method according to claim 1, characterized in that, The molar ratio of the initial product ZnSe and the additional Se powder in step (3) is 1:1-1.

2.

6. The preparation method according to claim 1, characterized in that, The grinding time in step (3) is 30-50 minutes; And / or, the pressure for cold pressing into a block in step (4) is 2-8 MPa.

7. The preparation method according to claim 1, characterized in that, The conditions for high-pressure sintering in step (4) are: sintering pressure of 4-7 GPa, sintering temperature and time of 500℃~800℃ for 1-5 hours or more, and finally natural cooling.

8. The preparation method according to claim 1, characterized in that, The conditions for high-pressure sintering in step (4) are as follows: the sintering pressure is 4-7 GPa, first hold at 600-800℃ for 30-60 minutes, the heating rate is 100-200℃ / minute, then cool down to 600℃ in 10-60 seconds and hold for 30-60 minutes, then cool down to 500℃ in 30 minutes, and finally cool naturally. Preferably, the conditions for high-pressure sintering in step (4) are as follows: the sintering pressure is 4 GPa, the temperature is first maintained at 800°C for 30 minutes, the heating rate is 200°C / minute, then the temperature is lowered to 600°C in 10 seconds and maintained for 30 minutes, then the temperature is lowered to 500°C in 30 minutes, and finally the temperature is allowed to cool naturally.

9. The preparation method according to claim 1, characterized in that, In step (6), step (5) is repeated 2-4 times.

10. The ZnSe2 inorganic compound material prepared by the preparation method according to any one of claims 1-9.

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