Chiral nickel oxide nanoparticles and preparation method thereof

Abstract

The present invention relates to the technical field of material chemistry, and in particular to a chiral nickel oxide nanoparticle and a preparation method thereof, wherein the preparation method comprises the following steps: S1, preparing a transition metal nickel ion reaction precursor solution and an oxalate ion reaction precursor solution; S2, adding the oxalate ion reaction precursor solution to the transition metal nickel ion reaction precursor solution to obtain a mixed solution; S3, stirring and heat-insulating in a water bath until a mixed turbid liquid is obtained; S4, centrifuging the mixed turbid liquid, and washing the centrifuged precipitate with deionized water and ethanol to obtain a chiral nickel oxalate nanomaterial; and S5, calcining to obtain a chiral nickel oxide nanoparticle. The present invention combines an inorganic compound with a chiral ligand to synthesize a chiral nickel oxalate precursor, and then calcining the chiral nickel oxalate precursor to obtain the chiral nickel oxide nanoparticle; a simple and efficient coprecipitation method and a calcination method are adopted, and the reaction conditions are easy to implement, the process is simple, the cost is low, and the chiral nickel oxide nanoparticle has good universality.

Description

Technical Field

[0001] The invention relates to the technical field of material chemistry, and in particular to chiral nickel oxide nanoparticles and a preparation method thereof. Background Art

[0002] Chirality is widely present in nature and is a concept involving solid geometry. It refers to the property that a substance or configuration cannot overlap with its mirror image through a series of spatial symmetry operations such as rotation and translation. Materials with this structural characteristic are called chiral materials. Chiral materials have special physical and chemical properties due to their special structural characteristics, including the differential absorption of circularly polarized light by chiral materials, namely circular dichroism. Chiral materials can be divided into two categories: chiral organic materials and chiral inorganic materials. Chiral organic materials have the advantages of mature synthesis methods and a wide range of types, but organic materials have poor stability and their circular dichroism signal response band is narrow. Compared with chiral organic materials, chiral inorganic nanomaterials have become an emerging type of chiral materials due to their advantages such as easy regulation of optical response bands and better stability.

[0003] Chiral inorganic nanomaterials have broad application prospects in the fields of chiral sensing, spintronic devices, asymmetric catalysis, photoelectrocatalysis and biomedicine. However, most inorganic nanomaterials are not chiral. At present, the main ways to impart chirality to chiral inorganic nanomaterials can be divided into: 1. Using the Coulomb interaction between chiral ligands and the surface of inorganic nanoparticles to adsorb chiral ligands on the surface of nanoparticles to achieve chirality transfer, thereby giving chirality to nanomaterials; 2. Using chiral templates, by combining inorganic nanoparticles with chiral templates, the chiral arrangement of nanoparticles along the chiral template is achieved, giving chirality to nanomaterials. However, there are few reports on the synthesis of chiral inorganic nanomaterials with morphological chirality. The chirality of inorganic chiral nanomaterials with morphological chirality is generated by the special asymmetric morphology of the material itself, and this special morphology is relatively difficult to synthesize. Therefore, how to prepare chiral inorganic nanomaterials with intrinsic morphology is one of the important challenges faced by the field of chiral inorganic materials. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a chiral nickel oxide nanoparticle and a preparation method thereof.

[0005] A method for preparing chiral nickel oxide nanoparticles comprises the following steps:

[0006] S1, preparing a transition metal nickel ion reaction precursor solution and an oxalate ion reaction precursor solution;

[0007] S2, adding the oxalate ion reaction precursor solution to the transition metal nickel ion reaction precursor solution to obtain a mixed solution;

[0008] S3, stirring the mixed solution and keeping it warm in a water bath until a mixed turbid solution is obtained;

[0009] S4, centrifuging the mixed turbid liquid, and washing the precipitate after centrifugation by multiple cross-washing with deionized water and ethanol to obtain chiral nickel oxalate nanomaterials;

[0010] S5, calcining the chiral nickel oxalate nanomaterial to obtain chiral nickel oxide nanoparticles.

[0011] Preferably, in S1, the preparation method of the transition metal nickel ion reaction precursor solution is as follows:

[0012] S111, adding a surfactant and a transition metal nickel salt to a first solvent to prepare a first intermediate solution; wherein the molar ratio of the surfactant to the transition metal nickel salt is 1:(4-30), the first solvent is a mixed solvent of ultrapure water and ethylene glycol in a volume ratio of 1:(0.5-2), and the concentration of the transition metal nickel salt in the first intermediate solution is 0.01-0.1 mol / L;

[0013] S112, adding a chiral ligand solution to the first intermediate solution under stirring conditions to obtain a second intermediate solution; wherein the molar ratio of the chiral ligand to the transition metal nickel salt is (0.1-3):1;

[0014] S113, stirring the second solution in a water bath at 15-50° C. for 3-30 minutes to obtain a transition metal nickel ion precursor solution.

[0015] Preferably, in S111, the surfactant solution is any one of a polyvinyl pyrrolidone solution, a sodium dodecyl sulfate solution, a dodecyl dimethyl benzyl ammonium chloride solution, a hexadecyl trimethyl ammonium bromide solution and a hexadecyl trimethyl ammonium chloride solution;

[0016] The transition metal nickel salt solution is any one of a nickel chloride solution, a nickel nitrate solution, a nickel acetate solution and a nickel bromide solution.

[0017] Preferably, in S112, the chiral ligand solution is any one of L-tartaric acid solution, D-tartaric acid solution, L-proline solution, D-proline solution, L-aspartic acid solution, D-aspartic acid solution, L-threonine solution, D-threonine solution, L-cysteine ​​solution, D-cysteine ​​solution, L-alanine, D-alanine, L-valine solution and D-valine solution.

[0018] Preferably, in S1, the preparation method of the oxalate ion reaction precursor solution is as follows:

[0019] S121, adding an oxalate ion reaction precursor to a second solvent to prepare a second intermediate solution; wherein the second solvent is a mixed solvent of ultrapure water and ethylene glycol in a volume ratio of 1:(0.5-5), and the concentration of oxalate ions in the second intermediate solution is 0.02-0.2 mol / L;

[0020] S122, placing the second intermediate solution in a water bath at 15-50° C. and stirring for 3-30 minutes to obtain an oxalate ion reaction precursor solution.

[0021] Preferably, in S121, the oxalate ion reaction precursor solution is any one of an ammonium oxalate solution, a sodium oxalate solution or a potassium oxalate solution.

[0022] Preferably, in S2, the molar ratio of transition metal nickel ions to oxalate ions in the mixed solution is 1:(1-2);

[0023] In the process of preparing the mixed turbid solution, the temperature of the mixed solution when heated is 15 to 50° C., and the insulation time is 3 to 12 hours.

[0024] Preferably, in S4, the centrifugal speed during centrifugation is 6000-10000 r / min, the centrifugal time is 3-15 min, and the number of centrifugal washings is 3-5 times.

[0025] Preferably, in S5, the calcination temperature is 400-700°C, the time is 2-10 hours, and the heating rate is 1-5°C / min.

[0026] The invention discloses chiral nickel oxide nanoparticles obtained by adopting a preparation method of chiral nickel oxide nanoparticles.

[0027] The present invention combines an inorganic compound with a chiral ligand to synthesize a chiral nickel oxalate precursor, and then calcines the chiral nickel oxalate precursor to obtain chiral nickel oxide nanoparticles with morphological chirality. The present invention adopts a simple and efficient coprecipitation method and calcination method, and its reaction conditions are easy to implement, the process is simple, the cost is low, and it has good universality. The prepared material has good crystallinity and stability, the chirality of the material belongs to morphological chirality, and this method is of great significance for constructing and regulating new chiral inorganic materials.

[0028] The invention also discloses a chiral nickel oxalate material; the material is synthesized by a coprecipitation method, has a simple preparation method, is highly controllable, and can be combined with a variety of chiral ligands to produce chiral transfer.

[0029] The invention also discloses a method for proving that the chiral nickel oxide nanoparticles have morphological chirality by grinding and destroying the morphology of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1is the XRD diagram of the chiral nickel oxide nanoparticles of the present invention;

[0031] Figure 2 is a scanning electron microscope image of the chiral nickel oxide nanoparticles of the present invention;

[0032] Figure 3 is a transmission electron microscope image of the chiral nickel oxide nanoparticles of the present invention;

[0033] Figure 4 is a circular dichroism spectrum diagram of the chiral nickel oxide nanoparticles of the present invention;

[0034] Figure 5 This is a transmission electron microscope image of the chiral nickel oxide nanoparticles after the morphology is destroyed;

[0035] Figure 6 This is a circular dichroism spectrum diagram of the chiral nickel oxide nanoparticles after the morphology is destroyed. DETAILED DESCRIPTION

[0036] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.

[0037] The present invention discloses a method for preparing chiral nickel oxide nanoparticles. Figure 1 , including the following steps:

[0038] S1, preparing a transition metal nickel ion reaction precursor solution and an oxalate ion reaction precursor solution.

[0039] The preparation method of the transition metal nickel ion reaction precursor solution is as follows:

[0040] Before preparation, the reaction container was treated by rinsing the glass bottle with deionized water, then ultrasonically cleaning it, and drying it for subsequent experiments.

[0041] S111, adding a surfactant and a transition metal nickel salt to a first solvent to prepare a first intermediate solution; wherein the molar ratio of the surfactant to the transition metal nickel salt is 1:(4-30), the first solvent is a mixed solvent of ultrapure water and ethylene glycol in a volume ratio of 1:(0.5-2), and the concentration of the transition metal nickel salt in the first intermediate solution is 0.01-0.1 mol / L;

[0042] The surfactant solution is any one of polyvinyl pyrrolidone solution, sodium dodecyl sulfate solution, dodecyl dimethyl benzyl ammonium chloride solution, hexadecyl trimethyl ammonium bromide solution and hexadecyl trimethyl ammonium chloride solution; the transition metal nickel salt solution is any one of nickel chloride solution, nickel nitrate solution, nickel acetate solution and nickel bromide solution.

[0043] S112, adding a chiral ligand solution to the first intermediate solution under stirring conditions to obtain a second intermediate solution; wherein the molar ratio of the chiral ligand to the transition metal nickel salt is (0.1-3):1.

[0044] The chiral ligand solution is any one of L-tartaric acid solution, D-tartaric acid solution, L-proline solution, D-proline solution, L-aspartic acid solution, D-aspartic acid solution, L-threonine solution, D-threonine solution, L-cysteine ​​solution, D-cysteine ​​solution, L-alanine, D-alanine, L-valine solution and D-valine solution.

[0045] S113, stirring the second solution in a water bath at 15 to 50° C. for 3 to 30 minutes to obtain a transition metal nickel ion precursor solution.

[0046] The preparation method of the precursor solution is as follows:

[0047] Before preparation, the reaction container was treated by rinsing the glass bottle with deionized water, then ultrasonically cleaning it, and drying it for subsequent experiments.

[0048] S121, adding an oxalate ion reaction precursor to a second solvent to prepare a second intermediate solution; wherein the second solvent is a mixed solvent of ultrapure water and ethylene glycol in a volume ratio of 1:(0.5-5), and the concentration of oxalate ions in the second intermediate solution is 0.02-0.2 mol / L;

[0049] The oxalate ion reaction precursor solution is any one of an ammonium oxalate solution, a sodium oxalate solution or a potassium oxalate solution.

[0050] S122, placing the second intermediate solution in a water bath at 15-50° C. and stirring for 3-30 minutes to obtain an oxalate ion reaction precursor solution.

[0051] S2, adding the oxalate ion reaction precursor solution to the transition metal nickel ion reaction precursor solution to obtain a mixed solution, wherein the molar ratio of the transition metal nickel ion to the oxalate ion in the mixed solution is 1:(1-2).

[0052] S3, heating the mixed solution in a water bath at 15-50° C. with stirring, and keeping the temperature for 3-12 hours, until a mixed turbid solution is obtained (whether it meets the requirements is determined by whether the Tyndall effect occurs), wherein the stirring rate is 500-1500 r / min.

[0053] S4, centrifuging the mixed turbid liquid, and washing the precipitate after centrifugation by multiple cross-washing with deionized water and ethanol to obtain chiral nickel oxalate nanomaterials;

[0054] The centrifugal speed during centrifugation is 4000r / min to 10000r / min, the centrifugal time is 3 to 15min, and the number of centrifugal washings is 3 to 5 times.

[0055] S5, calcining the chiral nickel oxalate nanomaterial to obtain chiral nickel oxide nanoparticles, wherein the calcination temperature is 400-700° C., the time is 2-10 hours, and the rate is 1-5° C. / min.

[0056] Example 1: Comparative test

[0057] Before preparation, the reaction container was treated by rinsing the glass bottle with deionized water, then ultrasonically cleaning it, and drying it for subsequent experiments.

[0058] Step 1: Preparation of achiral nickel oxalate nanomaterials

[0059] To a mixed solution of 16 mL of ultrapure water and 20 mL of ethylene glycol, add 2 mL of 0.5 mol / L nickel acetate aqueous solution and 2 mL of 10 mg / mL sodium dodecyl sulfate solution, stir at 1000 r / min for 15 min at 25 ° C to prepare a mixed solution of ultrapure water and ethylene glycol of surfactant and transition metal nickel salt, then add 2 mL of 0.5 mol / L DL-tartaric acid solution while stirring, mix well to obtain a transition metal nickel ion reaction precursor solution.

[0060] 2 mL of 0.5 mol / L ammonium oxalate solution was added to a mixed solution of 4 mL of ultrapure water and 14 mL of ethylene glycol, and the mixture was stirred at 1000 r / min for 30 min at 25° C. After mixing evenly, an oxalate ion reaction precursor solution was obtained.

[0061] The oxalate ion reaction precursor solution was added to the transition metal nickel ion reaction precursor solution, the molar ratio of oxalate ion to nickel ion was 1:1, and then the mixed solution was placed in a water bath and kept at 25°C for 6 hours. After the reaction was completed, the mixed solution was taken out and centrifuged at 6000r / min for 5 minutes to collect the precipitate, and then cross-washed with deionized water and ethanol for 4 times, and then dispersed in ultrapure water for standby use.

[0062] Step 2: Preparation of achiral nickel oxide nanoparticles

[0063] The obtained achiral nickel oxalate was placed in a muffle furnace and calcined at 450°C for 6 hours with a heating rate of 5°C / min. After cooling to room temperature, the obtained achiral nickel oxalate was taken out to obtain chiral nickel oxide nanoparticles.

[0064] Example 2

[0065] Before preparation, the reaction container was treated by rinsing the glass bottle with deionized water, then ultrasonically cleaning it, and drying it for subsequent experiments.

[0066] Step 1: Preparation of chiral nickel oxalate nanomaterials

[0067] To a mixed solution of 16 mL of ultrapure water and 20 mL of ethylene glycol, add 2 mL of 0.5 mol / L nickel acetate aqueous solution and 2 mL of 10 mg / mL sodium dodecyl sulfate solution, stir at 1000 r / min for 15 min at 25 ° C to prepare a mixed solution of ultrapure water and ethylene glycol of surfactant and transition metal nickel salt, then add 2 mL of 0.5 mol / L L-tartaric acid solution while stirring, mix well to obtain a transition metal nickel ion reaction precursor solution.

[0068] 2 mL of 0.5 mol / L ammonium oxalate solution was added to a mixed solution of 4 mL of ultrapure water and 14 mL of ethylene glycol, and the mixture was stirred at 1000 r / min for 15 min at 25° C. to obtain an oxalate ion reaction precursor solution after uniform mixing.

[0069] The oxalate ion reaction precursor solution was added to the transition metal nickel ion reaction precursor solution, the molar ratio of oxalate ion to nickel ion was 1:1, and then the mixed solution was placed in a water bath and kept warm at 25°C for 6 hours; after the reaction, the mixed solution was taken out and centrifuged at 6000r / min for 5 minutes to collect the precipitate, and it was cross-washed with deionized water and ethanol for 4 times, and then dispersed in ultrapure water for standby use.

[0070] Step 2: Preparation of chiral nickel oxide nanoparticles

[0071] The obtained chiral nickel oxalate was placed in a muffle furnace and calcined at 450°C for 6 hours, with a heating rate of 5°C / min. After cooling to room temperature, the chiral nickel oxide nanoparticles were obtained.

[0072] The chiral nickel oxide nanoparticles obtained in Example 2 were subjected to XRD and SEM analysis, and the results were as follows: Figure 1 and Figure 2 shown. Figure 1 From the XRD spectrum of the chiral nickel oxide nanoparticles prepared in Example 2 of the present invention, it can be seen that the material prepared in Example 2 only has characteristic peaks of nickel oxide, and no characteristic peaks of other substances appear, indicating that the material is nickel oxide and has high purity and crystallinity. Figure 2 This is a SEM photo of chiral nickel oxide nanoparticles prepared in Example 2 of the present invention. Figure 2 It can be seen that the chiral nickel oxide nanoparticles prepared in Example 2 have obvious irregular grooves and local distortions, which result in the inability to overlap with the mirror image. This may be the source of the chirality of the prepared chiral nickel oxide nanoparticles, that is, the chirality is morphological chirality.

[0073] Example 3

[0074] Before preparation, the reaction container was treated by rinsing the glass bottle with deionized water, then ultrasonically cleaning it, and drying it for subsequent experiments.

[0075] Step 1: Preparation of chiral nickel oxalate nanomaterials

[0076] To a mixed solution of 16 mL of ultrapure water and 20 mL of ethylene glycol, add 2 mL of 0.5 mol / L nickel acetate aqueous solution and 2 mL of 10 mg / mL sodium dodecyl sulfate solution, stir at 1000 r / min for 15 min at 25 ° C to prepare a mixed solution of ultrapure water and ethylene glycol of surfactant and transition metal nickel salt, then add 2 mL of 0.5 mol / L D-tartaric acid solution while stirring, mix well to obtain a transition metal nickel ion reaction precursor solution.

[0077] 2 mL of 0.5 mol / L ammonium oxalate solution was added to a mixed solution of 4 mL of ultrapure water and 14 mL of ethylene glycol, and the mixture was stirred at 1000 r / min for 15 min at 25° C. to obtain an oxalate ion reaction precursor solution after uniform mixing.

[0078] The oxalate ion reaction precursor solution was added to the transition metal nickel ion reaction precursor solution, the molar ratio of oxalate ion to nickel ion was 1:1, and then the mixed solution was placed in a water bath and kept warm at 25°C for 6 hours; after the reaction, the mixed solution was taken out and centrifuged at 6000r / min for 5 minutes to collect the precipitate, and it was cross-washed with deionized water and ethanol for 4 times, and then dispersed in ultrapure water for standby use.

[0079] Step 2: Preparation of chiral nickel oxide nanoparticles

[0080] The obtained chiral nickel oxalate was placed in a muffle furnace and calcined at 450°C for 6 hours, with a heating rate of 5°C / min. After cooling to room temperature, the chiral nickel oxide nanoparticles were obtained.

[0081] Figure 3 The transmission electron microscopy image of the chiral nickel oxide nanoparticles prepared in Example 3 of the present invention clearly shows that it is composed of small nanoparticles, which will provide a larger active surface area. In addition, its overall morphology is somewhat distorted, which may be the reason for the chirality.

[0082] Figure 4 The circular dichroism spectra of the chiral nickel oxide nanoparticles prepared in Examples 2 and 3 of the present invention are compared with the achiral nickel oxide nanoparticles prepared in Example 1; it can be seen that the CD curves of the L- and D-chiral nickel oxide nanoparticles prepared in Examples 2 and 3 are basically mirror-symmetric, while the CD curve of the achiral nickel oxide nanoparticles is basically maintained at 0, indicating that they are not chiral.

[0083] Example 4

[0084] Before preparation, the reaction container was treated by rinsing the glass bottle with deionized water, then ultrasonically cleaning it, and drying it for subsequent experiments.

[0085] Step 1: Preparation of chiral nickel oxalate nanomaterials

[0086] To a mixed solution of 16 mL ultrapure water and 20 mL ethylene glycol, add 2 mL of 0.5 mol / L nickel acetate aqueous solution and 2 mL of 10 mg / mL sodium dodecyl sulfate solution, stir at 1000 r / min for 15 min at 25 ° C to prepare a mixed solution of ultrapure water and ethylene glycol of surfactant and transition metal nickel salt, then add 1 mL of 0.5 mol / L L-tartaric acid solution while stirring, mix well to obtain a transition metal nickel ion reaction precursor solution.

[0087] 2 mL of 0.5 mol / L ammonium oxalate solution was added to a mixed solution of 4 mL of ultrapure water and 14 mL of ethylene glycol, and the mixture was stirred at 1000 r / min for 15 min at 25° C. to obtain an oxalate ion reaction precursor solution after uniform mixing.

[0088] The oxalate ion reaction precursor solution was added to the transition metal nickel ion reaction precursor solution, the molar ratio of oxalate ion to nickel ion was 1:1, and then the mixed solution was placed in a water bath and kept warm at 25°C for 6 hours; after the reaction, the mixed solution was taken out and centrifuged at 6000r / min for 5 minutes to collect the precipitate, and it was cross-washed with deionized water and ethanol for 4 times, and then dispersed in ultrapure water for standby use.

[0089] Step 2: Preparation of chiral nickel oxide nanoparticles

[0090] The obtained chiral nickel oxalate was placed in a muffle furnace and calcined at 500°C for 6 hours, with a heating rate of 5°C / min. After cooling to room temperature, the chiral nickel oxide nanoparticles were obtained.

[0091] Example 5

[0092] Before preparation, the reaction container was treated by rinsing the glass bottle with deionized water, then ultrasonically cleaning it, and drying it for subsequent experiments.

[0093] Step 1: Preparation of chiral nickel oxalate nanomaterials

[0094] To a mixed solution of 16 mL of ultrapure water and 20 mL of ethylene glycol, add 2 mL of 0.5 mol / L nickel acetate aqueous solution and 2 mL of 10 mg / mL sodium dodecyl sulfate solution, stir at 1000 r / min for 15 min at 25 ° C to prepare a mixed solution of ultrapure water and ethylene glycol of surfactant and transition metal nickel salt, then add 4 mL of 0.5 mol / L L-tartaric acid solution while stirring, mix well to obtain a transition metal nickel ion reaction precursor solution.

[0095] 2 mL of 0.5 mol / L ammonium oxalate solution was added to a mixed solution of 4 mL of ultrapure water and 14 mL of ethylene glycol, and the mixture was stirred at 1000 r / min for 15 min at 25° C. to obtain an oxalate ion reaction precursor solution after uniform mixing.

[0096] The oxalate ion reaction precursor solution was added to the transition metal nickel ion reaction precursor solution, the molar ratio of oxalate ion to nickel ion was 1:1, and then the mixed solution was placed in a water bath and kept warm at 25°C for 6 hours; after the reaction, the mixed solution was taken out and centrifuged at 6000r / min for 5 minutes to collect the precipitate, and it was cross-washed with deionized water and ethanol for 4 times, and then dispersed in ultrapure water for standby use.

[0097] Step 2: Preparation of chiral nickel oxide nanoparticles

[0098] The obtained chiral nickel oxalate was placed in a muffle furnace and calcined at 500°C for 6 hours, with a heating rate of 5°C / min. After cooling to room temperature, the chiral nickel oxide nanoparticles were obtained.

[0099] Example 6

[0100] Before preparation, the reaction container was treated by rinsing the glass bottle with deionized water, then ultrasonically cleaning it, and drying it for subsequent experiments.

[0101] Step 1: Preparation of chiral nickel oxalate nanomaterials

[0102] To a mixed solution of 16 mL of ultrapure water and 20 mL of ethylene glycol, add 2 mL of 0.5 mol / L nickel acetate aqueous solution and 2 mL of 10 mg / mL sodium dodecyl sulfate solution, stir at 1000 r / min for 15 min at 25 ° C to prepare a mixed solution of ultrapure water and ethylene glycol of surfactant and transition metal nickel salt, then add 2 mL of 0.5 mol / L L-tartaric acid solution while stirring, mix well to obtain a transition metal nickel ion reaction precursor solution.

[0103] 2 mL of 0.5 mol / L ammonium oxalate solution was added to a mixed solution of 4 mL of ultrapure water and 14 mL of ethylene glycol, and the mixture was stirred at 1000 r / min for 15 min at 25° C. to obtain an oxalate ion reaction precursor solution after uniform mixing.

[0104] The oxalate ion reaction precursor solution was added to the transition metal nickel ion reaction precursor solution, the molar ratio of oxalate ion to nickel ion was 1:1, and then the mixed solution was placed in a water bath and kept warm at 25°C for 10 hours; after the reaction, the mixed solution was taken out and centrifuged at 6000r / min for 5 minutes to collect the precipitate, and it was cross-washed with deionized water and ethanol for 4 times, and then dispersed in ultrapure water for standby use.

[0105] Step 2: Preparation of chiral nickel oxide nanoparticles

[0106] The obtained chiral nickel oxalate was placed in a muffle furnace and calcined at 500°C for 2 hours, with a heating rate of 5°C / min. After cooling to room temperature, the chiral nickel oxide nanoparticles were obtained.

[0107] Example 7

[0108] Before preparation, the reaction container was treated by rinsing the glass bottle with deionized water, then ultrasonically cleaning it, and drying it for subsequent experiments.

[0109] Step 1: Preparation of chiral nickel oxalate nanomaterials

[0110] To a mixed solution of 16 mL ultrapure water and 20 mL ethylene glycol, add 2 mL of 0.5 mol / L nickel acetate aqueous solution and 2 mL of 10 mg / mL sodium dodecyl sulfate solution, stir at 1000 r / min for 15 min at 25 ° C to prepare a mixed solution of ultrapure water and ethylene glycol of surfactant and transition metal nickel salt, then add 1 mL of 0.5 mol / L L-tartaric acid solution while stirring, mix well to obtain a transition metal nickel ion reaction precursor solution.

[0111] 2 mL of 0.5 mol / L ammonium oxalate solution was added to a mixed solution of 4 mL of ultrapure water and 14 mL of ethylene glycol, and the mixture was stirred at 1000 r / min for 15 min at 25° C. to obtain an oxalate ion reaction precursor solution after uniform mixing.

[0112] The oxalate ion reaction precursor solution was added to the transition metal nickel ion reaction precursor solution, the molar ratio of oxalate ion to nickel ion was 1:1, and then the mixed solution was placed in a water bath and kept warm at 25°C for 4 hours; after the reaction, the mixed solution was taken out and centrifuged at 6000r / min for 5 minutes to collect the precipitate, and it was cross-washed with deionized water and ethanol for 4 times, and then dispersed in ultrapure water for standby use.

[0113] Step 2: Preparation of chiral nickel oxide nanoparticles

[0114] The obtained nickel oxalate was placed in a muffle furnace and calcined at 450°C for 2 hours with a heating rate of 5°C / min. After cooling to room temperature, the obtained nickel oxalate was taken out to obtain chiral nickel oxide nanoparticles.

[0115] Example 8

[0116] Using the chiral nickel oxide nanoparticles prepared in Example 2, the prepared chiral nickel oxide nanoparticles were transferred to an agate mortar and ground for 10 minutes.

[0117] Figure 5 The transmission electron microscope image of the chiral nickel oxide nanoparticles prepared in Example 8 of the present invention after grinding and crushing shows that the morphology of the chiral nickel oxide nanoparticles is obviously broken after grinding, which confirms that the chiral nickel oxide nanoparticles are composed of small nanoparticles.

[0118] Example 9

[0119] Using the chiral nickel oxide nanoparticles prepared in Example 3, the prepared chiral nickel oxide nanoparticles were transferred to an agate mortar and ground for 10 minutes.

[0120] Figure 6 The circular dichroism spectra of the chiral nickel oxide nanoparticles prepared in Examples 8 and 9 of the present invention after grinding and crushing show that the CD of the chiral nickel oxide nanoparticles after grinding and crushing is basically 0, indicating that the chiral nickel oxide nanoparticles no longer have chirality after the morphology is crushed, which further confirms that the chirality of the chiral nickel oxide nanoparticles is morphological chirality.

[0121] The above description is only a preferred embodiment of the present invention and is not intended to impose any limitation on the technical solution of the present invention. Those skilled in the art should understand that, without departing from the spirit and principles of the present invention, the technical solution can also be subjected to several simple modifications and substitutions, and these modifications and substitutions are also within the scope of protection covered by the claims.

Claims

1. A method for preparing chiral nickel oxide nanoparticles, characterized in that: The following steps are involved: S1, preparing a transition metal nickel ion reaction precursor solution and an oxalate ion reaction precursor solution; Wherein, the preparation method of the transition metal nickel ion reaction precursor solution is as follows: S111, adding a surfactant and a transition metal nickel salt to a first solvent to prepare a first intermediate solution; wherein the molar ratio of the surfactant to the transition metal nickel salt is 1: (4 to 30), the first solvent is a mixed solvent of ultrapure water and ethylene glycol in a volume ratio of 1: (0.5 to 2), and the concentration of the transition metal nickel salt in the first intermediate solution is 0.01 to 0.1 mol / L; S112, adding a chiral ligand solution to the first intermediate solution under stirring conditions to obtain a second intermediate solution; wherein the molar ratio of the chiral ligand to the transition metal nickel salt is (0.1-3): 1; the chiral ligand solution is any one of L-tartaric acid solution, D-tartaric acid solution, L-proline solution, D-proline solution, L-aspartic acid solution, D-aspartic acid solution, L-threonine solution, D-threonine solution, L-cysteine ​​solution, D-cysteine ​​solution, L-alanine, D-alanine, L-valine solution and D-valine solution; S113, stirring the second intermediate solution in a water bath at 15-50° C. for 3-30 min to obtain a transition metal nickel ion precursor solution; S2, adding the oxalate ion reaction precursor solution to the transition metal nickel ion reaction precursor solution to obtain a mixed solution; S3, stirring the mixed solution and keeping it warm in a water bath until a mixed turbid solution is obtained; S4, centrifuging the mixed turbid liquid, and washing the precipitate after centrifugation by multiple cross-washing with deionized water and ethanol to obtain chiral nickel oxalate nanomaterials; S5, calcining the chiral nickel oxalate nanomaterial to obtain chiral nickel oxide nanoparticles.

2. The method for preparing chiral nickel oxide nanoparticles according to claim 1, characterized in that: In S111, the surfactant solution is any one of a polyvinyl pyrrolidone solution, a sodium dodecyl sulfate solution, a dodecyl dimethyl benzyl ammonium chloride solution, a hexadecyl trimethyl ammonium bromide solution and a hexadecyl trimethyl ammonium chloride solution; The transition metal nickel salt solution is any one of a nickel chloride solution, a nickel nitrate solution, a nickel acetate solution and a nickel bromide solution.

3. The method for preparing chiral nickel oxide nanoparticles according to claim 1, characterized in that: In S1, the preparation method of the oxalate ion reaction precursor solution is as follows: S121, adding an oxalate ion reaction precursor to a second solvent to prepare a second intermediate solution; wherein the second solvent is a mixed solvent of ultrapure water and ethylene glycol in a volume ratio of 1: (0.5-5), and the concentration of oxalate ions in the second intermediate solution is 0.02-0.2 mol / L; S122, placing the second intermediate solution in a water bath at 15-50° C. and stirring for 3-30 min to obtain an oxalate ion reaction precursor solution.

4. The method for preparing chiral nickel oxide nanoparticles according to claim 3, characterized in that: In S121, the oxalate ion reaction precursor solution is any one of an ammonium oxalate solution, a sodium oxalate solution or a potassium oxalate solution.

5. The method for preparing chiral nickel oxide nanoparticles according to claim 1, characterized in that: In S2, the molar ratio of transition metal nickel ions to oxalate ions in the mixed solution is 1: (1-2); In the process of preparing the mixed turbid solution, the temperature of the mixed solution when heated is 15~50℃, and the insulation time is 3~12h.

6. The method for preparing chiral nickel oxide nanoparticles according to claim 1, characterized in that: In S4, the centrifugal speed during centrifugation is 6000~10000 r / min, the centrifugal time is 3~15 min, and the number of centrifugal washings is 3~5 times.

7. The method for preparing chiral nickel oxide nanoparticles according to claim 1, characterized in that: In S5, the calcination temperature is 400~700 ℃, the time is 2~10h, and the heating rate is 1~5 ℃ / min.

8. Chiral nickel oxide nanoparticles obtained by the method for preparing chiral nickel oxide nanoparticles according to any one of claims 1 to 7.

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