MOLYBDENUM DISULFIDE POWDER AND METHOD FOR MANUFACTURING THE SAME, METHOD FOR DEGRADING AN ORGANIC MATERIAL AND METHOD FOR STERILIZING
A method for manufacturing a molybdenum disulfide powder includes conducting a precursor solution preparation step and a hydrothermal synthesis step. The precursor solution preparation step includes providing sodium molybdenum oxide dehydrate and thiourea, and conducting a mixing step. In the mixing step, an acid solution is mixed with the sodium molybdenum oxide dehydrate and the thiourea by titrating so as to form a precursor solution. In the hydrothermal synthesis step, the precursor solution is put into a hydrothermal container for reacting at a temperature ranging from 100° C. to 350° C. for 8 hours to 40 hours, thus the molybdenum disulfide powder is formed.
This application claims priority to Taiwan Application Serial Number 105102523, filed Jan. 27, 2016, which is herein incorporated by reference.
BACKGROUNDTechnical Field
The present disclosure relates to a molybdenum disulfide powder, a method for manufacturing the same, a method for degrading an organic material using the same, and a method for sterilizing using the same. More particularly, the present disclosure relates to a molybdenum disulfide powder with catalytic activity, a method for manufacturing the same, a method for degrading an organic material using the same, and a method for sterilizing using the same.
Description of Related Art
A photocatalyst is a substance which can accelerate a chemical reaction after irradiated with light. The common photocatalysts include gallium phosphide (GaP), gallium arsenide (GaAs), cadmium sulfide (CdS), stannic oxide (SnO2), zinc oxide (ZnO), titanium dioxide (TiO2), and so on. The photocatalyst can generate a plurality of electron-hole pairs after irradiated with light, in which the holes have oxidation ability and the electrons have reduction ability. The holes and the electrons can react with water molecules and oxygen molecules on a surface of the photocatalyst so as to generate hydroxyl radicals (OH.) and superoxide ions (O2−). The hydroxyl radicals have strong oxidation ability, the superoxide ions have strong reduction ability. By redox reactions, the photocatalyst can spoil cell membranes so as to achieve the sterilizing effect or can degrade organic gases or organic materials into water and carbon dioxide. Accordingly, a deodorization effect and a water purification effect can be achieved. The reaction between the holes and the water molecules and the reaction between the electrons and the oxygen molecules can be illustrated by Equation (1), Equation (2) and Equation (3):
hVB++H2O→H++OH. (1);
hVB++OH−→OH. (2); and
eCB−+O2→O2− (3).
The photocatalysts can use the sun light to induce the catalytic activity thereof and cause no secondary pollution, so draw a lot of attention. Among the photocatalysts, the titanium dioxide has a relatively stronger redox ability after irradiated with ultraviolet (UV) light and a stable chemical property. Furthermore, the titanium dioxide is harmless to the environment, and the material cost thereof is low. Accordingly, the titanium dioxide is becoming the mainstream material in the field of photocatalysts.
However, the catalytic activity of the photocatalyst is induced only when a certain energy is provided. Take the titanium dioxide for example, an energy greater than 3.2 eV (electronvolt) is required to induce the catalytic activity thereof, which is equivalent to an UV light with a wavelength lower than 387.5 nm. Although the sun light includes the UV light with the wavelength lower than 387.5 nm, the ratio of the UV light in the sun light is low. Therefore, the sun light cannot completely induce the catalytic activity of the titanium dioxide.
For solving the foregoing problem, a product equipped with an UV lamp is provided, whereby the photocatalyst is directly irradiated with the UV light for effectively enhancing the catalytic activity thereof. However, the UV light with a shorter wavelength is harmful to human body, so only can be used under certain conditions or environments, which is quite limited in use. Moreover, replacing the sun light with the UV lamp, an extra energy consumption is increased, which does not meet the demands of environmental protection and increases the cost.
To sum up, how to develop a new catalyst material, which does not rely on the irradiation of light with short wavelength and can provide desired catalytic activity, and can accordingly reduce energy consumption and cost, and meet the demands of environmental protection, is the goal of the related academia and industries.
SUMMARYAccording to one aspect of the present disclosure, a method for manufacturing a molybdenum disulfide powder includes steps as follows. A precursor solution preparation step is conducted, and a hydrothermal synthesis step is conducted. The precursor solution preparation step includes steps as follows. Sodium molybdenum oxide dehydrate and thiourea are provided, and a mixing step is conducted. In the mixing step, an acid solution is mixed with the sodium molybdenum oxide dehydrate and the thiourea by titrating so as to form a precursor solution. In the hydrothermal synthesis step, the precursor solution is put into a hydrothermal container for reacting at a temperature ranging from 100° C. to 350° C. for 8 hours to 40 hours, thus the molybdenum disulfide powder is formed.
According to another aspect of the present disclosure, a molybdenum disulfide powder is provided. The molybdenum disulfide powder is made by the method according to the foregoing aspect, and the molybdenum disulfide powder is stacked from a plurality of layered structures.
According to yet another aspect of the present disclosure, a method for degrading an organic material includes steps as follows. A molybdenum disulfide powder is provided, a contacting step is conducted, and a degrading step is conducted. The molybdenum disulfide powder is stacked from a plurality of layered structures, and at least one of the layered structures is an odd-layer structure. In the contacting step, the molybdenum disulfide powder is contacted with a medium, and the medium includes at least one organic material and water. In the degrading step, a mechanical perturbation is generated in the medium to polarize the molybdenum disulfide powder, and a pair of electron and hole are generated for degrading the organic material.
According to further another aspect of the present disclosure, a method for sterilizing includes steps as follows. A molybdenum disulfide powder is provided, a contacting step is conducted, and a sterilizing step is conducted. The molybdenum disulfide powder is stacked from a plurality of layered structures, and at least one of the layered structures is an odd-layer structure. In the contacting step, the molybdenum disulfide powder is contacted with a medium, and the medium includes at least one bacterium and water. In the sterilizing step, a mechanical perturbation is generated in the medium to polarize the molybdenum disulfide powder, and a pair of electron and hole are generated for killing the bacterium.
The present disclosure can be more fully understood by reading the following detailed description of the embodiment, with reference made to the accompanying drawings as follows:
In Step 110, a precursor solution preparation step is conducted. Please refer to
In Step 111, sodium molybdenum oxide dehydrate and thiourea are provided. A mole ratio of the sodium molybdenum oxide dehydrate to the thiourea can range from 1:0.5 to 1:5.
In Step 112, a mixing step is conducted, in which an acid solution is mixed with the sodium molybdenum oxide dehydrate and the thiourea by titrating so as to form a precursor solution, whereby it is favorable to conduct a reaction in a following hydrothermal synthesis step. According to one example of the present disclosure, an acid is mixed with deionized water to form the acid solution, and then the acid solution is titrated into a container having the sodium molybdenum oxide dehydrate and the thiourea. The acid is added for lowering a pH value of the precursor solution. The acid can be but is not limited to sulfuric acid, hydrochloric acid, nitric acid and acetic acid. The acid solution can be mixed with the sodium molybdenum oxide dehydrate and the thiourea with a titrating rate which is greater than 0 ml/min and is smaller than or equal to 2.03 ml/min. When the titrating rate is too fast, the molybdenum disulfide powder tends to agglomerate, which is unfavorable to form the molybdenum disulfide powder stacked from layered structures with fewer layers.
According to one example of the present disclosure, the precursor solution preparation step further includes providing a solution of 1-butyl-3-methylimidazolium chloride salt ([BMIM][Cl]) before conducting the mixing step. In other words, the solution of the [BMIM][Cl] is first mixed with the sodium molybdenum oxide dehydrate and the thiourea, and then the mixing step is conducted. A molar concentration of the [BMIM][Cl] in the precursor solution is greater than 0 M, and is smaller than or equal to 5M. When the molar concentration of the [BMIM][Cl] in the precursor solution is greater than 0 M, it is favorable the molybdenum disulfide powder to form a nanoflower structure stacked from layered structures. When the molar concentration of the [BMIM][Cl] in the precursor solution is smaller than or equal to 5M, an excessively large particle size of the nanoflower structure of the molybdenum disulfide powder can be prevented (i.e., an excessively large particle size of the molybdenum disulfide powder can be prevented). Accordingly, an excessive small specific surface area can be prevented.
Please refer back to
4Na2MoO4+9CS(NH2)2+H2O+6H+→4MoS2+Na2SO4+18NH3↓+6Na++9CO2↑.
In Step 210, a precursor solution preparation step is conducted. In Step 220, a hydrothermal synthesis step is conducted. The details of Step 210 and Step 220 can be the same as that of Step 110 and Step 120 in
In Step 230, a washing step is conducted, in which the molybdenum disulfide powder is first washed with deionized water and then washed with ethanol. According to one example of the present disclosure, the molybdenum disulfide powder can be first washed with deionized water for several times for preferably cleaning other chemical substances on the surface thereof. Then the molybdenum disulfide powder is washed with ethanol for rapid drying.
In Step 240, a drying step is conducted, in which the molybdenum disulfide powder dealt with the washing step is heated to dryness. The drying step is for removing the moisture remained in the molybdenum disulfide powder. The drying step can be conducted at a temperature ranging from 40° C. to 100° C. for 8 hours to 24 hours.
EXAMPLES AND COMPARATIVE EXAMPLES The First ExampleSodium molybdenum oxide dehydrate (0.002976 mole) and thiourea (0.009065 mole) are put into a beaker. Deionized water (60 ml) and hydrochloric acid (1 ml, 12 M) are mixed so as to form an acid solution. The acid solution is titrated into the beaker containing the sodium molybdenum oxide dehydrate and the thiourea in 30 minutes, then is stirred with magnet stirrer for 10 minutes, so that a precursor solution is obtained. Afterwards, the precursor solution is put into a hydrothermal container made of teflon and then put into an oven maintained at a temperature of 220° C. for 24 hours. Let the hydrothermal container stand still until the temperature thereof is reduced to the room temperature. The suspension in the hydrothermal container is centrifuged at 5,500 rpm for collecting a precipitation. Then the precipitation is washed with deionized water and then collected by centrifugation at 5,500 rpm, which is repeated four times. Then the precipitation is washed with ethanol and then collected by centrifugation at 5,500 rpm. The precipitation is put into the oven and is heated at 50° C. for 12 hours. Thus, the molybdenum disulfide powder of the first example is obtained. The molybdenum disulfide powder is black, and a mass thereof is about 4 g.
The Second ExampleSodium molybdenum oxide dehydrate (0.002976 mole) and thiourea (0.009065 mole) are put into a beaker, then a solution of [BMIM][Cl] (1 ml, 1 M) is put into the beaker. The solution of [BMIM][Cl] is mixed with the sodium molybdenum oxide dehydrate and the thiourea. Deionized water (59 ml) and hydrochloric acid (1 ml, 12 M) are mixed so as to form an acid solution. The acid solution is titrated into the beaker containing the sodium molybdenum oxide dehydrate and the thiourea in 30 minutes, then is stirred with magnet stirrer for 10 minutes, so that a precursor solution is obtained. The following steps are the same as that in the first example, and will not repeated herein.
The Third ExampleSodium molybdenum oxide dehydrate (0.002976 mole) and thiourea (0.009065 mole) are put into a beaker, then a solution of [BMIM][Cl](5 ml, 1 M) is put into the beaker. The solution of [BMIM][Cl] is mixed with the sodium molybdenum oxide dehydrate and the thiourea. Deionized water (55 ml) and hydrochloric acid (1 ml, 12 M) are mixed so as to form an acid solution. The acid solution is titrated into the beaker containing the sodium molybdenum oxide dehydrate and the thiourea in 30 minutes, then is stirred with magnet stirrer for 10 minutes, so that a precursor solution is obtained. The following steps are the same as that in the first example, and will not repeated herein.
The Fourth ExampleSodium molybdenum oxide dehydrate (0.002976 mole) and thiourea (0.009065 mole) are put into a beaker, then a solution of [BMIM][Cl] (10 ml, 1 M) is put into the beaker. The solution of [BMIM][Cl] is mixed with the sodium molybdenum oxide dehydrate and the thiourea. Deionized water (50 ml) and hydrochloric acid (1 ml, 12 M) are mixed so as to form an acid solution. The acid solution is titrated into the beaker containing the sodium molybdenum oxide dehydrate and the thiourea in 30 minutes, then is stirred with magnet stirrer for 10 minutes, so that a precursor solution is obtained. The following steps are the same as that in the first example, and will not repeated herein.
The First Comparative ExampleA commercial available molybdenum disulfide powder (purchased from Sigma Aldrich Corporation) has a particle size smaller than 2 μm.
The Second Comparative ExampleSodium molybdenum oxide dehydrate (0.002976 mole) and thiourea (0.009065 mole) are dissolved with deionized water (60 ml), then is stirred with magnet stirrer until a clear and transparent solution is obtained. Then hydrochloric acid (1 ml, 12 M) contained in a dropper is titrated into the solution with a titrating rate of 6 ml/min, then is stirred with magnet stirrer for 10 minutes, so that a precursor solution is obtained. The following steps are the same as that in the first example, and will not repeated herein.
The Third Comparative ExampleA rhodamine solution has a concentration of 10 ppm.
The Fourth Comparative ExampleA commercial available titanium dioxide powder (purchased from Sigma Aldrich Corporation) has an average particle size of 21 nm, and a specific surface area ranging from 35 m2/g to 65 m2/g.
Molybdenum Disulfide PowderResults of SEM and TEM:
A cold field emission SEM (Hitachi SU8010) is used to observe the surface morphology of the molybdenum disulfide powder of the first example to the fourth example at 10 k magnification and at 50 k magnification with an accelerating voltage of 10 kV. A high resolution TEM (JEOL JEM-3000F) is used to observe the arrangement of atoms, the crystalline property and the selected area diffraction (SAD) pattern of the molybdenum disulfide powder of the first example to the fourth example.
1. The First ExampleResults of XRD.
A XRD (Bruker D2 phaser) is used to analyze the structure of the molybdenum disulfide powder of the second example and the first comparative example. The measuring range of 2θ is 10° to 70°, the step size is 0.03°, and the scanning speed is 0.2°/sec.
Please refer to
Results of Raman Spectrometer:
A Raman spectrometer is used to analyze the vibration modes between atoms of the molybdenum disulfide powder according to the second example and the first comparative example, a 532 nm laser is used as the excitation laser, and the scanning range is set from 370 cm−1 to 420 cm−1. Please refer to
Please refer to
Results of Specific Surface Area Analysis:
A surface area and porosimetry analyser (Micromeritics ASAP 2020) is used to measure the specific surface areas of the molybdenum disulfide powder of the first example to the fourth example. The specific surface areas of the first example to the fourth example are 69.21 cm2/g, 52.64 cm2/g, 35.28 cm2/g and 23.35 cm2/g in sequence. According to the results, it can be concluded that when the amount of [BMIM]+ is increased, thicknesses of the petals of the nanoflowers are increased. Accordingly, the specific surface area is decreased.
Results of AFM:
An AFM is used to observe the piezoelectic property of the molybdenum disulfide powder of the second example. Please refer to
As shown in the foregoing results, the method according to the present disclosure is favorable to manufacture the molybdenum disulfide powder stacked from the layered structures with fewer layers. Also, the method according to the present disclosure is favorable to manufacture the molybdenum disulfide powder stacked from the layered structures with odd layers.
Method for Degrading an Organic MaterialIn Step 310, a molybdenum disulfide powder is provided, wherein the molybdenum disulfide powder is stacked from a plurality of layered structures, and at least one of the layered structures is an odd-layer structure. The molybdenum disulfide powder can be manufactured by the method according to the present disclosure (the method for manufacturing a molybdenum disulfide powder 100 and 200).
In Step 320, a contacting step is conducted, wherein the molybdenum disulfide powder is contacted with a medium, and the medium includes at least one organic material and water.
In Step 330, a degrading step is conducted, wherein a mechanical perturbation is generated in the medium to polarize the molybdenum disulfide powder, and a pair of electron and hole are generated for degrading the organic material.
Please refer to
Please further refer to
Please further refer to
As shown in
In Step 510, a molybdenum disulfide powder is provided. The molybdenum disulfide powder is stacked from a plurality of layered structures, and at least one of the layered structures is an odd-layer structure. The molybdenum disulfide powder can be manufactured by the method according to the present disclosure (the method for manufacturing a molybdenum disulfide powder 100 and 200).
In Step 520, a contacting step is conducted, wherein the molybdenum disulfide powder is contacted with a medium, and the medium includes at least one bacterium and a water.
In Step 530, a sterilizing step is conducted, wherein a mechanical perturbation is generated in the medium to polarize the molybdenum disulfide powder, and a pair of electron and hole are generated for killing the bacterium. The schematic view showing the pairs of electron and hole generated from the molybdenum disulfide powder can refer to
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present disclosure without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the present disclosure cover modifications and variations of this disclosure provided they fall within the scope of the following claims.
Claims
1. A method for manufacturing a molybdenum disulfide powder, comprising:
- conducting a precursor solution preparation step, comprising: providing sodium molybdenum oxide dehydrate and thiourea; and conducting a mixing step, wherein an acid solution is mixed with the sodium molybdenum oxide dehydrate and the thiourea by titrating so as to form a precursor solution; and
- conducting a hydrothermal synthesis step, wherein the precursor solution is put into a hydrothermal container for reacting at a temperature ranging from 100° C. to 350° C. for 8 hours to 40 hours, thus the molybdenum disulfide powder is formed.
2. The method for manufacturing the molybdenum disulfide powder of claim 1, further comprising:
- conducting a washing step, wherein the molybdenum disulfide powder is first washed with deionized water and then washed with ethanol; and
- conducting a drying step, wherein the molybdenum disulfide powder dealt with the washing step is heated to dryness.
3. The method for manufacturing the molybdenum disulfide powder of claim 1, wherein a mole ratio of the sodium molybdenum oxide dehydrate to the thiourea ranges from 1:0.5 to 1:5.
4. The method for manufacturing the molybdenum disulfide powder of claim 1, wherein the precursor solution preparation step further comprises:
- providing a solution of 1-butyl-3-methylimidazolium chloride salt before conducting the mixing step, wherein the solution of the 1-butyl-3-methylimidazolium chloride salt is mixed with the sodium molybdenum oxide dehydrate and the thiourea.
5. The method for manufacturing the molybdenum disulfide powder of claim 4, wherein a molar concentration of the 1-butyl-3-methylimidazolium chloride salt in the precursor solution is greater than 0 M and is smaller than or equal to 5M.
6. The method for manufacturing the molybdenum disulfide powder of claim 1, wherein the acid solution is mixed with the sodium molybdenum oxide dehydrate and the thiourea with a titrating rate, and the titrating rate is greater than 0 ml/min and is smaller than or equal to 2.03 ml/min.
7. A molybdenum disulfide powder made by the method according to claim 1, wherein the molybdenum disulfide powder is stacked from a plurality of layered structures.
8. The molybdenum disulfide powder of claim 7, wherein an average particle size of the molybdenum disulfide powder ranges from 0.2 μm to 10 μm.
9. The molybdenum disulfide powder of claim 7, wherein at least one of the layered structures is an odd-layer structure.
10. A method for degrading an organic material, comprising:
- providing a molybdenum disulfide powder, wherein the molybdenum disulfide powder is stacked from a plurality of layered structures, and at least one of the layered structures is an odd-layer structure;
- conducting a contacting step, wherein the molybdenum disulfide powder is contacted with a medium, and the medium comprises at least one organic material and water, and
- conducting a degrading step, wherein a mechanical perturbation is generated in the medium to polarize the molybdenum disulfide powder, and a pair of electron and hole are generated for degrading the organic material.
11. The method for degrading the organic material of claim 10, wherein the medium is an aqueous solution.
12. The method for degrading the organic material of claim 11, wherein the organic material is rhodamine or methylene blue.
13. The method for degrading the organic material of claim 11, wherein the mechanical perturbation is generated by an ultrasonic wave.
14. The method for degrading the organic material of claim 10, wherein the medium is an air.
15. The method for degrading the organic material of claim 14, wherein the organic material is an organic gas.
16. A method for sterilizing, comprising:
- providing a molybdenum disulfide powder, wherein the molybdenum disulfide powder is stacked from a plurality of layered structures, and at least one of the layered structures is an odd-layer structure;
- conducting a contacting step, wherein the molybdenum disulfide powder is contacted with a medium, and the medium comprises at least one bacterium and water; and
- conducting a sterilizing step, wherein a mechanical perturbation is generated in the medium to polarize the molybdenum disulfide powder, and a pair of electron and hole are generated for killing the bacterium.
17. The method for sterilizing of claim 16, wherein the medium is an air or an aqueous solution.
Type: Application
Filed: May 25, 2016
Publication Date: Jul 27, 2017
Inventors: Jyh-Ming WU (Hsinchu County), Wei-En CHANG (Miaoli County)
Application Number: 15/163,696