CN111498895A

CN111498895A - Cu2-xMethod for regulating and controlling S nanosheet crystal structure

Info

Publication number: CN111498895A
Application number: CN202010397009.6A
Authority: CN
Inventors: 陈礼辉; 胡海峰; 陈育宙; 方文韬; 李国华
Original assignee: Zhejiang University of Technology ZJUT
Current assignee: Zhejiang University of Technology ZJUT
Priority date: 2020-05-12
Filing date: 2020-05-12
Publication date: 2020-08-07
Anticipated expiration: 2040-05-12
Also published as: CN111498895B

Abstract

The invention provides a Cu_2‑xS(0<x is less than or equal to 1) a regulation and control method of a nanosheet crystal structure, belonging to the field of nano materials, and the method comprises the following steps: using inorganic copper salt as a copper source, respectively injecting four organic solutions containing a sulfur source into a mixed solution of the copper salt and an organic solvent by a hot injection method under the conditions of inert gas protection and magnetic stirring, and reacting at a certain temperature to prepare Cu with different crystal structures_2‑xAnd (3) S nanosheet. Four Cu species as described above, influenced by the concentration of copper vacancies_2‑xS nanosheets exhibit distinct uv-vis-nir absorption properties. In addition to this, Cu in a certain crystal structure_2‑xThe S nanosheet is used as a mother set, and the mutual conversion of the crystal structures of the S nanosheet is realized by using different sulfur sources. The raw materials used by the invention are common and low in priceSimple preparation, convenient operation and good product repeatability.

Description

Cu2-xMethod for regulating and controlling S nanosheet crystal structure

(I) technical field

The invention relates to Cu_2-xA method for regulating and controlling the crystal structure of an S nanosheet.

(II) background of the invention

Localized surface plasmon resonance (L SPR) refers toL SPR exists not only In noble metals such as gold and silver, but also In heavily Doped semiconductors (L uter, J.M.; Jain, P.K.; Ewers, T.; Alivisatos, A.P.; L affected Surface plasma resources In Doped Quantum dots, Nature Materials,2011,10,361-³⁺Doped CdO, Sn⁴⁺Doped In₂O₃、Al³⁺Doped ZnO and self-doped WO_3-x、Cu_2-xS、Cu_2-xSe et al have L SPR with response wavelengths primarily concentrated in the near infrared region (Agrawal, A.; Cho, S.H.; Zandi, O.; Ghosh, S.; Johns, R.W.; Million, D.J. L encapsulated Surface plasma Resonance in semiconductor nanocrystals, 2018,118, 3121-.

Of many L SPR semiconductors, Cu_2-xS has attracted increasing attention due to its diversity of crystal structures and tunability of copper vacancy concentration. Cu can be effectively regulated by a chemical oxidation-reduction method_2-xS copper vacancy concentration is further regulated and controlled to L SPR, however, L SPR has a very limited range of variation (Chen, L H.; Hu, H.F.; L i, Y.; Chen, R.; L i, G.H.FlexibleTuning of House-Based L affected Surface plasma reaction in Roxbyite Cu.)_1.8SNanodisks via Particle Size,Carrier Density and Plasmon Coupling.Journal ofMaterials Science,2020,55,116-124.)。Cu_2-xS has a plurality of crystal structures and contains chalcocite Cu without copper vacancies₂Covellite CuS with S changed to be rich in copper vacancy and with crystal structure opposite to Cu_2-xL SPR wavelength and vibration intensity of S have important effects (Hsu, S.W.; Ngo, C.; Tao, A.R.tunable and Directional plasma coupling with in Semiconductor Nanodisk assemblies. Nano L ets, 2014,14, 2372-_2-xS is for example djurleite Cu_1.94S、roxbyite Cu_1.8S and covellite CuS have been widely used in the fields of surface-enhanced Raman scattering, photothermal conversion, photocatalysis, etc. (Kriegel, I; Scotogennella, F.; Mannaa, L. Plasmonic Doped S(iii) epoxy resins, Properties, contamination, Applications and perspectives, Physics Reports,2017,674, 1-52.). To make Cu_2-xS is suitable for application in a specific near infrared light region, and has important research significance in regulating and controlling the crystal structure of the S. However, Cu is prepared with respect to the system_2-xThe S crystal structure and its influence on L SPR and the interconversion of crystal structure are rarely studied other scholars have also produced Cu of different crystal structures by different methods (CN108658600A, CN106830049A and CN108862366A)_2-xS is e.g. Cu₂S、Cu_1.97S、Cu₉S₅And CuS, but do not relate to how to use different sulfur sources to realize Cu_2-xRegulation and control of S crystal structure and influence thereof on L SPR, and realization of Cu by using different sulfur sources_2-xAnd (4) interconversion of S crystal structure. Therefore, development of a regulated Cu_2-xThe S nano material crystal structure is simple and feasible, and the method with good repeatability has important theoretical and practical significance for researching L SPR influence, interconversion and potential application development.

Disclosure of the invention

Aiming at regulating and controlling Cu by utilizing the reaction activity of the existing sulfur source_2-xS(0<x is less than or equal to 1) crystal structure and the problem and the defect of the preparation method of interconversion thereof, the invention aims to provide the Cu with simple and easily obtained raw materials, convenient operation and good repeatability_2-xAnd S nano material crystal structure regulating and controlling method.

The technical scheme adopted by the invention is as follows:

cu_2-xS(0<x is less than or equal to 1) a regulation and control method of a nanosheet crystal structure, the method comprising:

(1) taking a mixed solution of an inorganic copper salt and a high-boiling-point organic solvent as an initiator, heating to 100-160 ℃ under vacuum and magnetic stirring, and keeping for 10-60 min to remove water, oxygen and low-boiling-point organic matters in the mixed solution to obtain an inorganic copper salt mixed solution; the inorganic copper salt is one of the following: copper chloride, copper nitrate, copper sulfate, copper phosphate, or cuprous chloride; the high boiling point organic solvent is one of the following or a mixture of more than two of the following: oleylamine, oleic acid or octadecene;

(2) taking four organic solutions containing a sulfur source, respectively injecting the four organic solutions into the organic copper salt mixed solution, repeatedly degassing by using a Schlenk system, and keeping the four organic solutions at the original temperature or heating to 210-240 ℃ for 10-60 min under the inert gas atmosphere; the organic solution comprising a sulfur source is one of: n-dodecyl mercaptan ultrasonic dispersion oleylamine solution, dibutyl thiourea ultrasonic dispersion oleylamine solution, sulfur powder ultrasonic dispersion oleic acid solution or sulfur powder n-octadecene high-temperature (150-180 ℃) solution;

(3) after the reaction is finished, naturally cooling to room temperature, adding a detergent, performing ultrasonic dispersion, centrifuging to remove generated organic matters and unreacted starting materials, and obtaining the Cu_2-xAnd dispersing and storing the S nanosheet by using an organic solvent.

Under the conditions of inert gas protection and magnetic stirring, different organic solutions containing sulfur source are injected into the mixed solution of inorganic copper salt and organic solvent by adopting a hot injection method, and the reaction is carried out at a certain temperature to prepare Cu with different crystal structures_2- _xAnd (3) S nanosheet.

Specifically, when different organic solutions containing sulfur sources are adopted in the step (2), the different organic solutions correspond to different Cu_2-xS nanosheet crystal structure:

specifically, the detergent in the step (3) is one of the following or a mixture of two or more of the following: toluene, methanol, ethanol, propanol or acetone.

The organic solvent for dispersion in the step (3) is one of the following or a mixture of two or more of the following: chloroform, hexane or toluene.

With a kind of Cu_2-xThe S nanosheet is a mother plate, and the mutual conversion of the crystal structures can be realized by using different sulfur sources:

the covellite CuS sodium is preparedThe rice flakes were converted to djurleite Cu by the following method_1.94S nanosheet: dispersing covellite CuS nanosheets by using n-octadecene and oleylamine (volume ratio is 1: 0.5-2), vacuumizing by using a Schlenk system, heating to 100-160 ℃ under magnetic stirring, keeping the temperature for 10-60 min to remove water, oxygen and low-boiling-point organic matters in a mixed solution, filling nitrogen, injecting n-dodecyl mercaptan ultrasonic dispersion oleylamine solution, keeping the temperature for 20-40 min at 100-160 ℃, naturally cooling to room temperature, adding a detergent, performing ultrasonic dispersion, centrifuging to remove generated organic matters and unreacted starting materials completely, and obtaining djurlite Cu_1.94And (3) S nanosheet.

The obtained djurleite Cu_1.94The S nanosheet is converted to digenite Cu by the following method_1.8S nanosheet: dJurleite Cu_1.94Dispersing S nanosheets by using n-octadecene and oleylamine (volume ratio is 1: 0.5-2), vacuumizing by using a Schlenk system, heating to 100-160 ℃ under magnetic stirring and keeping for 10-60 min to remove water, oxygen and low-boiling-point organic matters in a mixed solution, filling nitrogen, injecting dibutyl thiourea ultrasonic dispersion oleylamine solution or sulfur powder n-octadecene high-temperature solution, keeping for 20-40 min at 100-160 ℃, naturally cooling to room temperature, adding a detergent, performing ultrasonic dispersion, centrifuging to remove generated organic matters and unreacted starting materials completely, and obtaining digenite Cu_1.8And (3) S nanosheet.

Prepared digenite Cu_1.8The S nanosheets are converted into covellite CuS nanosheets by the following method: digenite Cu_1.8Dispersing S nanosheets by using n-octadecene and oleylamine (volume ratio is 1: 0.5-2), vacuumizing by using a Schlenk system, heating to 100-160 ℃ under magnetic stirring, keeping the temperature for 10-60 min to remove water, oxygen and low-boiling-point organic matters in the mixed solution, filling nitrogen, injecting sulfur powder into the mixed solution, ultrasonically dispersing the oleylamine solution, keeping the temperature for 100-160 ℃ for 20-40 min, naturally cooling to room temperature, adding a detergent, ultrasonically dispersing, centrifuging to remove generated organic matters and unreacted starting materials, and obtaining covellite CuS nanosheets.

The advantages of the invention are mainly reflected in that: (1) provides a simple and effective Cu regulation and control method by utilizing different reaction activities of various sulfur sources_2-xS nanomaterial crystal structure and interaction thereofA method of preparation of the conversion; (2) the used sulfur source raw materials are common, the cost is low, the product appearance and size are uniform, the repeatability is good, and the large-scale production is easy to realize; (3) prepared Cu_2-xS has response to different wavelengths of near infrared light and is suitable for photothermal therapy, photocatalysis and other applications in a specific wavelength range.

(IV) description of the drawings

FIG. 1 is Cu_2-xAnd (3) experimental schematic diagrams of regulation and control of S nanosheet crystal structures and interconversion of the S nanosheet crystal structures.

FIG. 2 is a digital photograph and UV-VIS absorption spectrum of four organic solutions containing a sulfur source used in the examples; in the figure, sulfur source 1: ultrasonic dispersion of oleylamine solution with n-dodecyl mercaptan, sulfur source 2: dibutyl thiourea ultrasonic dispersion oleylamine solution, sulfur source 3: sulfur powder n-octadecylene high-temperature dissolving solution, sulfur source 4: and ultrasonically dispersing the oleylamine solution by using sulfur powder.

FIG. 3 shows the sheet-like Cu obtained in example 1_2-xTEM and XRD patterns of S nanoparticles.

FIG. 4 shows the sheet-like Cu obtained in example 2_2-xTEM and XRD patterns of S nanoparticles.

FIG. 5 shows the sheet-like Cu obtained in example 3_2-xTEM and XRD patterns of S nanoparticles.

FIG. 6 shows the sheet-like Cu obtained in example 4_2-xTEM and XRD patterns of S nanoparticles.

FIG. 7 shows the sheet-like Cu obtained in examples 1 to 4_2-xUltraviolet-visible-near infrared absorption diagram of S nanoparticles.

FIG. 8 shows Cu flakes initiated by different sulfur sources in example 5_2-xThe XRD patterns of the S nanoparticle crystal structure interconverted.

(V) detailed description of the preferred embodiments

For the purpose of enhancing understanding of the present invention, the present invention will be described in further detail with reference to specific examples, which are provided for illustration only and are not intended to limit the scope of the present invention.

The reagents used in the invention are all conventional chemical reagents unless otherwise specified; the experimental methods are all conventional methods.

The method adopts Philips-FEI company of the NetherlandsFor Cu by high-resolution transmission electron microscope (Tecnai G2F 30 type)_2-xAnd (5) characterizing the morphology of the S nano particles. The X-ray diffractometer model X' Pert PRO of the company PANALYTICAL, the Netherlands is adopted to diffract Cu_2- _xAnd (5) characterizing the crystal structure of the S nano particles, and performing continuous scanning in a scanning range of 10-80 degrees. Cu was measured by means of a spectrophotometer model U-4100 manufactured by HITACHI corporation of Japan_2-xThe L SPR response of the S nano-particles is tested, and the test wavelength range is 300 nm-2500 nm.

Example 1:

putting 1.0mmol of cuprous chloride into a 50m L three-neck flask, accurately transferring 10.0m L n-octadecene into the three-neck flask by using a liquid transfer gun to form a reaction mixed solution, connecting a Schlenk system at the middle end of the three-neck flask, sealing two ends of the side edge by using rubber stoppers, starting a vacuum pump, heating the reaction mixed solution to 140 ℃ under the condition of magnetic stirring, vacuumizing to remove water, oxygen and low-boiling organic matters, filling nitrogen after 30min, injecting 5.0m L oleylamine solution containing 3.0mmol of n-dodecanethiol obtained by ultrasonic dispersion into the three-neck flask by using a glass syringe, heating to 220 ℃ to keep 40min after reaction, naturally cooling to room temperature, adding 5.0m L toluene and 30.0m L ethanol, performing ultrasonic centrifugation for 10min, dispersing the centrifuged product by using 5.0m L trichloromethane or toluene, and hermetically storing for further characterization.

Produced flake Cu_2-xThe TEM image and the XRD image of the S nano-particle are shown in FIG. 3, and the crystal structure of the prepared nano-sheet is djulerite Cu_1.94S。

Example 2:

putting 1.0mmol of cuprous chloride into a 50m L three-neck flask, accurately transferring 10.0m L n-octadecene into the three-neck flask by using a liquid transfer gun to form a reaction mixed solution, connecting a Schlenk system at the middle end of the three-neck flask, sealing two ends of the side edge by using rubber stoppers, starting a vacuum pump, heating the reaction mixed solution to 140 ℃ under the condition of magnetic stirring, vacuumizing to remove water, oxygen and low-boiling organic matters, filling nitrogen after 30min, injecting a 5.0m L oleylamine solution containing 3.0mmol of dibutylthiourea obtained by ultrasonic dispersion into the three-neck flask by using a glass syringe, keeping the temperature at 140 ℃ for 5min, naturally cooling to room temperature after the reaction is finished, adding 5.0m L toluene and 30.0m L ethanol, performing ultrasonic centrifugation for 10min, dispersing the centrifuged product by using 5.0m L trichloromethane or toluene, and hermetically storing for further characterization.

Produced flake Cu_2-xThe TEM image and the XRD image of the S nano-particle are shown in figure 4, and the crystal structure of the prepared nano-sheet is roxbyite Cu_1.8S。

Example 3:

putting 1.0mmol of cuprous chloride into a 50m L three-neck flask, accurately transferring 10.0m L n-octadecene into the three-neck flask by using a liquid transfer gun to form a reaction mixed solution, connecting a Schlenk system at the middle end of the three-neck flask, sealing two sides by using rubber stoppers, starting a vacuum pump, heating the reaction mixed solution to 140 ℃ under the condition of magnetic stirring, vacuumizing to remove water, oxygen and low-boiling organic matters, filling nitrogen after 30min, injecting a sulfur powder n-octadecene solution (0.5 mol/L and 6.0m L) obtained by dissolving at high temperature (160 ℃) into the three-neck flask by using a glass syringe, keeping the temperature at 140 ℃ for 30min, naturally cooling to room temperature after the reaction is finished, adding 5.0m L toluene and 30.0m L ethanol, performing ultrasonic treatment for 10min, dispersing the product after the centrifugation for 10min by using 5.0m L trichloromethane or toluene, and hermetically storing for further characterization.

Produced flake Cu_2-xThe TEM image and the XRD image of the S nanoparticle are shown in FIG. 5, and the crystal structure of the prepared nanosheet is digenite Cu_1.8S。

Example 4:

putting 1.0mmol of cuprous chloride into a 50m L three-neck flask, accurately transferring 10.0m L n-octadecene into the three-neck flask by using a liquid transfer gun to form a reaction mixed solution, connecting a Schlenk system at the middle end of the three-neck flask, sealing two ends of the side edge by using rubber stoppers, starting a vacuum pump, heating the reaction mixed solution to 140 ℃ under the condition of magnetic stirring, vacuumizing to remove water, oxygen and low-boiling organic matters, filling nitrogen after 30min, injecting 5.0m L oleylamine solution containing 3.0mmol of sulfur powder obtained by ultrasonic dispersion into the three-neck flask by using a glass syringe, keeping the temperature at 140 ℃ for 5min, naturally cooling to room temperature after the reaction is finished, adding 5.0m L toluene and 30.0m L ethanol, performing ultrasonic treatment for 10min, then centrifuging for 10min, dispersing the product by using 5.0m L trichloromethane or toluene, and hermetically storing for further characterization.

Produced flake Cu_2-xReferring to fig. 6, a TEM image and an XRD image of the S nanoparticle show that the crystal structure of the prepared nanosheet is covellite CuS.

Sheet Cu obtained in examples 1 to 4_2-xThe ultraviolet-visible-near infrared absorption diagram of the S nanoparticles is shown in FIG. 7, from which it can be seen that Cu_2-xThe crystal structure of the S nanoparticle has a significant effect on its L SPR response.

Example 5:

putting 0.5mmol of covellite CuS nanosheet prepared into a 50m L three-neck flask, accurately transferring 5.0m L n-octadecene and 5.0m L oleylamine into the three-neck flask by using a liquid transfer gun to form a reaction mixed solution, connecting a Schlenk system at the middle end of the three-neck flask, sealing two ends of the side edge by using rubber stoppers, starting a vacuum pump, heating the reaction mixed solution to 140 ℃ under the condition of magnetic stirring, vacuumizing to remove water, oxygen and low-boiling organic matters, filling nitrogen after 10min, injecting 5.0m L oleylamine solution containing 10.0mmol of n-dodecanethiol obtained by ultrasonic dispersion into the three-neck flask by using a glass syringe, keeping the temperature at 140 ℃ for 30min after reaction is finished, naturally cooling to the room temperature, adding 5.0m L toluene and 30.0m L ethanol, performing ultrasonic treatment for 10min, and centrifuging to obtain a product djurlite Cu after 10min centrifugation_1.94The S nanosheets were dispersed with 5.0m L chloroform or toluene and stored in a closed environment for further characterization.

Then 0.5mmol of the obtained djurleite Cu is used for preparing_1.94S nanosheet is a reactant, under the same experimental condition, a 3.0m L oleylamine solution containing 1.5mmol of dibutyl thiourea or a sulfur powder n-octadecene high-temperature (160 ℃) dissolving solution (0.5 mol/L and 3.0m L) obtained by ultrasonic dispersion is injected into a three-mouth flask by using a glass syringe, and the temperature is kept at 140 ℃ for 30min to prepare digenite Cu_1.8And (3) S nanosheet.

Finally, digenite Cu was prepared at 0.5mmol_1.8S nano-sheet is reactant, same experimental stripAnd injecting a 3.0m L oleylamine solution containing 1.5mmol of sulfur powder obtained by ultrasonic dispersion into a three-neck flask by using a glass syringe, and keeping the temperature at 140 ℃ for 30min to obtain the covellite CuS nanosheet.

Different sulfur source initiated sheet Cu_2-xThe XRD pattern of the S nanoparticle crystal structure interconverting is shown in fig. 8.

Claims

1. Cu_2-xA method of modulating the crystal structure of S nanosheets, the method comprising:

(1) taking a mixed solution of an inorganic copper salt and a high-boiling-point organic solvent as an initiator, heating to 100-160 ℃ under magnetic stirring, and keeping for 10-60 min to remove water, oxygen and low-boiling-point organic matters in the mixed solution to obtain an inorganic copper salt mixed solution; the inorganic copper salt is one of the following: copper chloride, copper nitrate, copper sulfate, copper phosphate, or cuprous chloride; the high boiling point organic solvent is one of the following or a mixture of more than two of the following: oleylamine, oleic acid or octadecene;

(2) taking four organic solutions containing a sulfur source, respectively injecting the four organic solutions into the inorganic copper salt mixed solution, repeatedly degassing by using a Schlenk system, and keeping the four organic solutions at the original temperature or heating to 210-240 ℃ for 10-60 min under the inert gas atmosphere; the organic solution comprising a sulfur source is one of: n-dodecyl mercaptan ultrasonic dispersion oleylamine solution, dibutyl thiourea ultrasonic dispersion oleylamine solution, sulfur powder ultrasonic dispersion oleic acid solution or sulfur powder n-octadecene high temperature solution;

2. The method of claim 1, wherein different organic solutions containing a sulfur source are used in step (2) for different Cu_2-xS nanosheet crystal structure:

3. the method according to claim 1, wherein the detergent in the step (3) is one of the following or a mixture of two or more thereof: toluene, methanol, ethanol, propanol or acetone.

4. The method according to claim 1, wherein the organic solvent for dispersion in the step (3) is one of the following or a mixture of two or more thereof: chloroform, hexane or toluene.

5. The method of claim 2, wherein the covellite CuS nanoplates produced are converted to djurleite Cu nanoplates by the method_1.94S nanosheet: dispersing covellite CuS nanosheets by using n-octadecene and oleylamine, vacuumizing by using a Schlenk system, heating to 100-160 ℃ under magnetic stirring, keeping the temperature for 10-60 min to remove water, oxygen and low-boiling-point organic matters in the mixed solution, filling nitrogen, injecting n-dodecyl mercaptan ultrasonic dispersion oleylamine solution, keeping the temperature for 20-40 min at 100-160 ℃, naturally cooling to room temperature, adding a detergent, performing ultrasonic dispersion, centrifuging to remove generated organic matters and unreacted starting materials completely, and obtaining djurlite Cu_1.94And (3) S nanosheet.

6. The method of claim 2, wherein the djurleite Cu produced is_1.94The S nanosheet is converted to digenite Cu by the following method_1.8S nanosheet: dJurleite Cu_1.94Dispersing S nano sheets by using n-octadecylene and oleylamine, vacuumizing by using a Schlenk system, heating to 100-160 ℃ under magnetic stirring, keeping the temperature for 10-60 min to remove water, oxygen and low-boiling-point organic matters in the mixed solution, filling nitrogen, injecting dibutyl thiourea ultrasonic dispersion oleylamine solution or sulfur powder n-octadecylene high-temperature solution, and keeping the temperature for 100-160 ℃ to be 20 ℃. (to)After 40min, naturally cooling to room temperature, adding a detergent, performing ultrasonic dispersion, centrifuging to remove generated organic matters and unreacted starting materials to obtain digenite Cu_1.8And (3) S nanosheet.

7. The method of claim 2, wherein digenite Cu is produced_1.8The S nanosheets are converted into covellite CuS nanosheets by the following method: digenite Cu_1.8Dispersing S nanosheets by using n-octadecene and oleylamine, vacuumizing by using a Schlenk system, heating to 100-160 ℃ under magnetic stirring, keeping the temperature for 10-60 min to remove water, oxygen and low-boiling-point organic matters in a mixed solution, filling nitrogen, injecting sulfur powder into the mixed solution, ultrasonically dispersing the oleylamine solution, keeping the temperature for 20-40 min at 100-160 ℃, naturally cooling to room temperature, adding a detergent, ultrasonically dispersing, centrifuging to remove generated organic matters and unreacted starting materials completely, and obtaining covellite CuS nanosheets.