Disclosure of Invention
In order to overcome the problems of the prior art, one object of the present invention is to provide a composite nanomaterial, another object of the present invention is to provide a preparation method of the composite nanomaterial, and another object of the present invention is to provide an application of the composite nanomaterial.
The present invention is made based on the following recognition and findings of the inventors:
the noble metal coated copper sulfide nano material is prepared by a traditional template growth method, and after the inner core copper sulfide is generated, a large amount of ascorbic acid is still required to be introduced as a reducing agent to realize the growth of the nano noble metal crystal; however, the existence of a large amount of ascorbic acid in the reaction system leads to the self-nucleation of nano noble metal crystals, a large number of single nano noble metal particles (byproducts) are formed, the yield of the final product (the nano noble metal-coated hollow cubic copper sulfide) is influenced, the surface of the product is impure, a large amount of ascorbic acid is attached, and the components of the material and the exposed crystal face cannot be effectively used, so that the subsequent application is influenced; in addition, the ascorbic acid attached to the surface of the material tends to cause instability of physical and chemical properties of the material, and the material is easy to adhere to the wall during centrifugation, so that other stabilizers (such as sodium citrate) are required to protect the stability of the material. The inventor finds that the reducibility of polyvinylpyrrolidone (PVP) on the surface of the core copper sulfide is activated by properly increasing the temperature of a reaction system, growth sites and nucleation growth are provided for nano noble metal crystals, ascorbic acid is not required to be introduced in the growth process of noble metals, the self-nucleation of the nano noble metal crystals is avoided, the obtained final product has high purity, the polyvinylpyrrolidone can directly stabilize the whole reaction system, and the obtained product has good physical and chemical stability.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
in a first aspect, embodiments of the present invention provide a composite nanomaterial that is nano precious metal coated hollow cubic copper sulphide nanoflowers.
Preferably, in the composite nano material, the molar ratio of the nano noble metal to the hollow cubic copper sulfide nano rice is (1-5): 10; further preferably, the molar ratio of the noble metal nanoparticles to the hollow cubic copper sulfide nanoflowers is (2-4): 10.
preferably, in the composite nano material, the nano noble metal is at least one selected from nano gold, nano silver, nano palladium and nano platinum. In some embodiments of the present invention, the nano noble metal is nano gold.
In a second embodiment of the present invention, there is provided a method for preparing a composite nanomaterial according to the first embodiment of the present invention, comprising the steps of:
1) mixing a polyvinylpyrrolidone solution and a Cu (II) salt solution, adding alkali, adding a reducing agent, and mixing for reaction to obtain a cuprous oxide solution;
2) heating the cuprous oxide solution, and adding sulfide salt to react to obtain a hollow cubic copper sulfide solution;
3) and (3) centrifuging the hollow cubic copper sulfide solution, heating, and adding a noble metal source solution for reaction to obtain the composite nano material.
Preferably, in the step 1) of the preparation method of the composite nano material, the concentration of the polyvinylpyrrolidone solution is 5 g/L-20 g/L; more preferably, the concentration of the polyvinylpyrrolidone solution is 8g/L to 15 g/L.
Preferably, in the step 1) of the preparation method of the composite nano material, the concentration of the Cu (II) salt solution is 0.05 mol/L-0.2 mol/L; more preferably, the concentration of the Cu (II) salt solution is 0.08mol/L to 0.15 mol/L.
Preferably, in the step 1) of the preparation method of the composite nano material, the mass ratio of the polyvinylpyrrolidone to the Cu (II) salt is (30-100): 1; more preferably, the mass ratio of the polyvinylpyrrolidone to the Cu (II) salt is (40-60): 1.
preferably, in step 1) of the preparation method of the composite nano material, the Cu (II) salt is selected from at least one of copper nitrate, copper acetate, copper chloride and copper sulfate. In some embodiments of the invention, the Cu (II) salt is copper acetate.
Preferably, in step 1) of the preparation method of the composite nano material, the molar ratio of the Cu (II) salt to the alkali is 1: (10-30); further preferably, the molar ratio of Cu (ii) salt to base is 1: (15-20).
Preferably, the method for preparing the composite nanomaterial comprises step 1) wherein the base is selected from the group consisting of alkali metal hydroxides, alkali metal carbonates,At least one of alkali metal bicarbonate; further preferably, the alkali is selected from one or a combination of sodium hydroxide and potassium hydroxide. In practical application, the preparation can be carried out in the form of an alkaline solution. By adding alkali, the pH value of the solution can be adjusted to be alkaline, and the formation of Cu (OH) by Cu (II) salt coordination is further accelerated4 2-The intermediate is favorable for the generation of cuprous oxide.
Preferably, in step 1) of the preparation method of the composite nano material, the molar ratio of the Cu (II) salt to the reducing agent is 1: (1-5); further preferably, the molar ratio of the Cu (ii) salt to the reducing agent is 1: (2-4).
Preferably, in step 1) of the preparation method of the composite nano material, the reducing agent is selected from at least one of sodium borohydride, ascorbic acid, glucose and ammonium citrate. In some embodiments of the invention, ascorbic acid is selected as the reducing agent.
Preferably, in the step 2) of the preparation method of the composite nano material, the heating temperature is 80-95 ℃; further preferably, the heating temperature is 85 to 90 ℃.
Preferably, in step 2) of the preparation method of the composite nano material, the molar ratio of the sulfide salt to the Cu (II) salt in step 1) is (2-8): 1; more preferably, the molar ratio of the sulfide salt to the Cu (II) salt is (3-5): 1.
preferably, in step 2) of the preparation method of the composite nanomaterial, the sulfide salt is selected from at least one of sodium sulfide, potassium sulfide and ammonium sulfide. In some embodiments of the invention, the salt is sodium sulfide.
In the step 2) of the preparation method of the composite nano material, after the sulfide salt is added for reaction, the solution is gradually changed into dark green from light yellow, and then the reaction is continued for 1 to 3 hours.
Preferably, in step 3) of the preparation method of the composite nano material, the rotation speed of centrifugal treatment is 7000 r/min to 9000 r/min; further preferably, the rotation speed of the centrifugal treatment is 7500 rpm to 8500 rpm.
Preferably, in step 3), the time of centrifugal treatment is 10-30 minutes; more preferably, the time for the centrifugation is 15 to 25 minutes.
Preferably, in the step 3) of the preparation method of the composite nano material, the heating temperature is 50-70 ℃; more preferably, the heating temperature is 55 to 65 ℃. In some embodiments of the invention, the heating temperature of step 3) is 60 ℃.
Preferably, in the step 3) of the preparation method of the composite nano material, the mass concentration of the noble metal source solution is 0.5-2%; more preferably, the noble metal source solution has a mass concentration of 0.8% to 1.2%.
Preferably, in step 3) of the preparation method of the composite nanomaterial, the noble metal source is selected from at least one of chloroauric acid, silver nitrate, silver ammonia, palladium acetate and chloroplatinic acid. In some embodiments of the invention, the noble metal source is chloroauric acid.
In the step 3) of the preparation method of the composite nano material, after the noble metal source solution is added for reaction, the solution gradually changes from dark green to dark blue, and then the reaction is continued for 10 to 30 minutes.
The embodiment of the third aspect of the invention provides an application of the composite nano material in the biomedical field or organic dye sewage treatment, wherein the composite nano material is the composite nano material in the embodiment of the first aspect of the invention or the composite nano material prepared by the preparation method in the embodiment of the second aspect of the invention.
Preferably, the composite nano material is used as a drug carrier material when applied to the field of biomedicine.
Preferably, when the composite nano material is applied to organic dye sewage treatment, the composite nano material, an organic dye reducing agent and the organic dye sewage are mixed for treatment.
Preferably, when the composite nano material is applied to organic dye sewage treatment, the molar ratio of the composite nano material to the organic dye is (3-5): 1; further preferably, the molar ratio of the composite nano material to the organic dye is (3.5-4.5): 1.
preferably, when the composite nano material is applied to organic dye sewage treatment, the molar ratio of the organic dye reducing agent to the organic dye is (2000-3000): 1; more preferably, the molar ratio of the organic dye reducing agent to the organic dye is (2400-2600): 1.
preferably, when the composite nano material is applied to organic dye sewage treatment, the organic dye reducing agent is selected from at least one of alkali metal hydride and alkali metal borohydride; further preferably, the organic dye reducing agent is at least one selected from sodium borohydride and potassium borohydride.
Preferably, when the composite nano material is applied to the sewage treatment of the organic dye, the organic dye comprises at least one of 4-nitrophenol, 2, 4-dinitrophenol and 4-nitrobenzaldehyde.
The invention has the beneficial effects that:
according to the invention, by providing a template growth method, harsh reaction conditions such as high temperature, high pressure, organic solvent and the like are not required, and by introducing amphiphilic molecule polyvinylpyrrolidone as a crystal face sealing agent, a stabilizing agent and a reducing agent, the green environment-friendly nano noble metal-coated hollow cubic copper sulfide nano material (hollow cubic copper sulfide @ noble metal nano flower) with controllable appearance, uniform particle size and high biological safety can be obtained, and the template growth method can be applied to the field of biomedicine or organic dye sewage treatment.
Specifically, compared with the prior art, the invention has the following advantages:
1) according to the preparation method, no additional reducing agent is required to be added in the growth process of the noble metal, and the polyvinylpyrrolidone on the surface of the copper sulfide core can be used as the reducing agent and the stabilizing agent, so that the growth sites and the nucleation growth are provided for the noble metal nanocrystals.
2) The preparation method can effectively control the shape and size of the core-copper sulfide and shell-noble metal nanocrystals, and the obtained final product is in a nanometer level (100-200nm), and has more outstanding advantages compared with a micrometer level material.
3) The composite nano material prepared by the invention has high noble metal yield which can reach 95 percent or more.
4) The composite nano material prepared by the invention is in a uniform phase with water, and is suitable for application in the field of biomedicine.
5) The composite nano-material core copper sulfide prepared by the invention is of a hollow structure and can be used for carrying and releasing medicaments.
6) The composite nano material prepared by the invention has good catalytic degradation efficiency on organic dye 4-nitrophenol in water.
Detailed Description
The present invention will be described in further detail with reference to specific examples. The starting materials, reagents or equipment used in the examples are, unless otherwise specified, either conventionally commercially available or may be obtained by methods known in the art. Unless otherwise indicated, the testing or testing methods are conventional in the art.
Examples of production of composite nanomaterial
First, preparation of solution
Preparing a copper acetate solution: 0.40g of copper acetate monohydrate (Cu (CH)3COO)·H2O, 99%) was added to 20mL of triple deionized water and dissolved by sonication to give a 0.1mol/L copper acetate solution.
Preparing a sodium hydroxide solution: 0.40g of sodium hydroxide (NaOH, 99%) particles were weighed into 10mL of triple deionized water and dissolved by sonication to give a 1mol/L sodium hydroxide solution.
Preparing an ascorbic acid solution: 176mg of ascorbic acid (C) was weighed6H8O697%) was added to 10mL of triple deionized water and dissolved by sonication to give a 0.1mol/L ascorbic acid solution.
Preparing a sodium sulfide solution: 0.48g of sodium sulfide nonahydrate (Na) was weighed out2S·9H2O, 99%) was added to 20mL of triple deionized water and dissolved by sonication to give a 0.1mol/L sodium sulfide solution.
Preparing a chloroauric acid solution: 1g of chloroauric acid trihydrate (HAuCl)4·3H2O, Au 23.5-23.8%) is added to 80mL of triple deionized water and dissolved by ultrasonic to obtain a 1 wt% chloroauric acid solution.
Preparation of hollow cubic copper sulfide
(1) Preparation of cuprous oxide: adding 500 mu L of copper acetate (0.1mol/L) solution into 50mL of deionized water containing 0.5g of polyvinylpyrrolidone, magnetically stirring for 10min, dropwise adding 900 mu L of sodium hydroxide (1mol/L), continuously stirring for 2min, dropwise adding 1.5mL of ascorbic acid (0.1mol/L) solution, continuously stirring, stopping stirring when the solution gradually turns to light yellow from light blue, and standing for 20min to obtain the cuprous oxide solution.
(2) Preparation of copper sulfide: and (2) stirring and heating the prepared cuprous oxide solution, injecting 2mL of sodium sulfide (0.1mol/L) solution at one time when the temperature is heated to 90 ℃, gradually changing the solution from light yellow to dark green, continuously reacting for 2h, cooling to room temperature, sealing for later use, obtaining a hollow cubic copper sulfide solution, and storing for several months at room temperature.
SEM analysis is carried out on the intermediate product hollow cubic copper sulfide obtained by preparation, and figure 1 is a scanning electron microscope picture of the hollow cubic copper sulfide nano material. Based on the contrast comparison of the edges and the middle portion of the individual hollow cubic copper sulfide of fig. 1, the edges of the copper sulfide were found to be lighter in color and the middle portion was found to be darker in color, indicating that the copper sulfide nanomaterial was a hollow cubic structure.
Preparation of hollow cubic copper sulfide nanoflower coated with nanogold
10mL of the above prepared hollow cubic copper sulfide solution was placed in a plastic centrifuge tube, centrifuged at 8000 rpm for 20min, washed twice with deionized water, and finally resuspended in 10mL of deionized water, dried and weighed to 10.96 mg. Then placing 10mL of centrifuged 1mmol/L hollow cubic copper sulfide solution into a 20mL glass reaction bottle, starting stirring and heating, dropwise adding 100 mu L of 1 wt% (about 30mmol/L) chloroauric acid solution when the temperature rises to 60 ℃, gradually changing the solution from dark green to dark blue, continuing to react for 20min, taking out the reaction bottle, standing and cooling to room temperature to obtain the nano-gold-coated hollow cubic copper sulfide nanoflower, drying and weighing 11.52mg, wherein the yield of the nano-gold on the hollow cubic copper sulfide nanoflower can be calculated to reach 95%. The nano-gold coated hollow cubic copper sulfide nanoflower is tested by inductively coupled plasma atomic emission spectrometry (ICP-AES), and the results show that the mass concentrations of gold and copper are 59mg/L and 63.5mg/L respectively, so that the molar ratio of the nano-gold to the hollow cubic copper sulfide nanoflower can be calculated to be 3: 10.
SEM analysis is carried out on the prepared product of the hollow cubic copper sulfide nanoflower coated with the nano-gold, and figure 2 is a scanning electron microscope picture of the hollow cubic copper sulfide nanoflower coated with the nano-gold. Comparison of the product morphology with that of fig. 1 revealed that the flower-like grown gold nanoparticles in fig. 2 had completely covered the copper sulfide core, indicating the successful preparation of the nanogold-coated hollow cubic copper sulfide nanoflowers.
Tests show that amphiphilic molecule polyvinylpyrrolidone is introduced into an aqueous phase solution as a crystal face sealant, a reducing agent and a stabilizer by utilizing a template growth method, so that the morphology and the particle size of the core copper sulfide and the uniform growth of the shell gold nanocrystals are accurately controlled, and the preparation of the nano-grade gold-coated hollow copper sulfide nanoflowers with good biological safety is realized.
Application example
The hollow cubic copper sulfide nanoflower coated with nanogold is applied to catalytic degradation of organic dye 4-nitrophenol, and the specific experimental conditions and the test method are as follows:
preparing 0.5mol/L sodium borohydride (NaBH)4) Solution: 0.19g of NaBH is weighed out4The powder is put into 10mL of deionized water for three times to obtain 0.5mol/L NaBH4And (3) solution.
Preparing 10 mmol/L4-nitrophenol (C)6H5NO34-NTP) solution: 0.012g of 4-NTP powder was weighed out in 10mL of absolute ethanol to obtain a 10mmol/L solution of 4-NTP.
Taking 900 mu L of nano-gold coated hollow cubic copper sulfide nanoflower solution with concentration of 0.8mmol/L and 900 mu L of NaBH4The solution (0.5mol/L) is uniformly mixed in a quartz cuvette, 18 mu L of 4-NTP ethanol solution (10mmol/L) is added, and the mixture is immediately tested by using a UV2550 ultraviolet spectrophotometer (test conditions: the spectrum scanning range is 300-550 nm, the scanning speed is medium speed, and the spectrum bandwidth is 1nm), wherein the data at the moment is defined as the absorption of the system when the reaction time t is 0. The reaction was then spectrally collected every 2min and the absorbance at 405nm was recorded. A comparative example was made by making hollow cubic copper sulphide nanoflowers without the addition of nanogold coating.
FIG. 3 is an absorbance diagram of nano-gold coated hollow cubic copper sulfide nanoflower and sodium borohydride on catalytic degradation of a 4-nitrophenol solution, and FIG. 4 is an absorbance diagram of sodium borohydride on catalytic degradation of the 4-nitrophenol solution. As can be seen from FIG. 3, when nanogold-coated hollow cubic copper sulfide nanoflowers were present in the test system, 4-NTP was rapidly catalytically degraded, the absorbance of 4-NTP at 405nm gradually decreased with time, and at 18min, about 75% of 4-NTP had been degraded. As can be seen from FIG. 4, when there is no nanogold-coated hollow cubic copper sulfide nanoflower, the absorbance of 4-NTP at 405nm is slightly reduced, namely after 18min, which indicates that the nanogold-coated hollow cubic copper sulfide nanoflower has good catalytic degradation efficiency for 4-NTP.
FIG. 5 is a graph showing the catalytic kinetics of 4-nitrophenol. In FIG. 5, curve A shows the catalytic kinetics of sodium borohydride to 4-nitrophenol solution, and curve B shows the catalytic kinetics of nanogold coated hollow cubic copper sulfide nanoflower and sodium borohydride to 4-nitrophenol solution. As can be seen from fig. 5, when only sodium borohydride is present in the reaction system, the trend of curve a decreases insignificantly, and once the hollow cubic copper sulfide nanoflower coated with nanogold exists, curve B rapidly decreases, only 18min, and about 75% of 4-NTP has been degraded, indicating that the hollow cubic copper sulfide nanoflower coated with nanogold has high catalytic activity for 4-NTP.
In addition, the nanogold-coated hollow cubic copper sulfide nanoflowers provided by the invention have good biological safety and are suitable for the biomedical field, such as carrier materials for preparing medicines, and the carrier materials are used for carrying and releasing the medicines.
The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.