CN111595918A

CN111595918A - Octahedron Cu-Cu2Preparation method of O composite material

Info

Publication number: CN111595918A
Application number: CN202010452564.4A
Authority: CN
Inventors: 刘会俏; 曹康哲; 张航; 曹纬琪
Original assignee: Xinyang Normal University
Current assignee: Xinyang Normal University
Priority date: 2020-05-26
Filing date: 2020-05-26
Publication date: 2020-08-28

Abstract

The invention belongs to the technical field of nano material preparation, and particularly relates to octahedral Cu-Cu₂The preparation method of the O composite material comprises the following steps: adding Cu (NO)₃)₂Dissolving in PVP solution, adding NaOH solution and hydrazine hydrate while stirring in ice water bath, reacting until the color of the solution is not changed, continuing stirring, centrifuging to separate precipitate to obtain Cu-Cu₂An O precursor material; the obtained Cu-Cu₂Carrying out vacuum drying on the O precursor material to obtain brown powder, and then calcining at 200-450 ℃ in an argon atmosphere to obtain the Cu-Cu₂And (3) an O composite material.The method can be completed in a common reaction vessel without complex equipment in the whole process, has simple process steps, short preparation time, safety, reliability, no generation of toxic or polluted gas, low energy consumption and convenient expanded production, and the amount of Cu in the composite material prepared by the method can be regulated and controlled by controlling the calcination conditions, so the method is simple to operate.

Description

Octahedron Cu-Cu2Preparation method of O composite material

Technical Field

The invention belongs to the technical field of nano material preparation, and particularly relates to octahedral Cu-Cu₂A preparation method of an O composite material.

Background

In recent years, nanomaterials have received increasing attention. The nano material has a large specific surface area and good electron transfer capacity, and the nano material such as platinum, gold, silver, carbon nano tube, graphene and the like is widely used for electrochemical biosensing. The electrocatalytic performance of the nano material depends not only on the size and the elemental composition of the material, but also on the morphology of the material, and the crystal face with high surface energy often shows higher electrocatalytic activity than the crystal with low surface energy. Therefore, the rational design and controllable preparation of nanomaterials have become a hot spot of recent research.

Cu₂O is a novel P-type semiconductor material, has active electron-hole pairs, can show good catalytic activity, and has potential application value in the aspects of electrode materials, solar cells, sensors, photocatalysis and the like. Cu₂The common structures of O include cubic, octahedral, nanorod, nanotube, etc. Wherein (111) crystal face is dominant Cu₂The O catalytic performance is better than that of the material with the dominant crystal faces of (100) and (110). However, Cu₂The poor conductivity of O limits its further use in electrochemical sensing. Control Cu in reasonable design₂When the O crystal face is simultaneously added, Cu can be improved₂O quantum efficiency, increasing its conductivity.

At present Cu₂The preparation methods of O and its compound mainly include electrochemical deposition, microwave synthesis, solvothermal method, liquid phase synthesis, seed regulation and control method and microemulsion method, for example, Chinese patent CN102357659A discloses a Cu-Cu₂Preparation of O heterojunctions, i.e. using Cu₂Adding hydrazine hydrate into suspension solution of O powder and water to obtain Cu₂And growing a suspension solution of Cu particles on the surface of the O. Cu with different sizes and appearances can be obtained by the methods₂And O. However, Cu in these processes₂The synthesis process of O is relatively complicatedThe time is long, and some devices need high-temperature heating equipment. Next, Cu-Cu was prepared by the above-mentioned method₂The O compound is complicated in steps, and the content of Cu in the compound cannot be accurately regulated and controlled.

Disclosure of Invention

For solving the problem of the existing preparation of Cu-Cu₂The O compound preparation method has the problems of long time consumption, complicated steps and incapability of regulating and controlling the Cu content, and the invention provides octahedral Cu-Cu₂A preparation method of an O composite material.

In order to achieve the purpose, the invention adopts the following technical scheme:

octahedron Cu-Cu₂The preparation method of the O composite material comprises the following steps:

step A. adding Cu (NO)₃)₂Dissolving in PVP solution to obtain mixed solution, adding NaOH solution and hydrazine hydrate into the mixed solution while stirring in ice water bath, reacting until the solution color does not change, continuing stirring, and centrifuging to separate precipitate to obtain Cu-Cu₂An O precursor material;

step B, the Cu-Cu obtained in the step A₂Carrying out vacuum drying on the O precursor material to obtain brown powder, and then calcining at 200-450 ℃ in an argon atmosphere to obtain the Cu-Cu₂And (3) an O composite material.

Further, the mass fraction of the PVP solution is 2-5%, and the relative molecular mass of the PVP is 58000.

Further, the Cu (NO)₃)₂The molar ratio of hydrazine hydrate to hydrazine hydrate is 1: 5.

further, Cu (NO) in the step A₃)₂The molar ratio of the NaOH to the NaOH is (100-200): 1.

further, the continuous stirring time in the step A is 0.5-2 h.

Further, the temperature of vacuum drying in the step B is 40-60 ℃, and the time is 10-12 hours.

Further, the calcination time in the step B is 1-2 h.

The reaction principle of the invention is as follows: cu (NO) in the present invention₃)₂As a substrate, PVP solution as a surfaceThe activator guides the growth of crystal faces in the crystal growth process, when the mass fraction of the PVP solution in the reaction mixed solution is lower than 2%, the product is in a non-octahedral structure, the appearance and the structure are not affected by excessive PVP solution, and the redundant PVP solution can be removed through a subsequent centrifugation step. NaOH solution regulates the reaction mixture to be alkaline, when the sodium hydroxide is too little, the product is in a sheet shape, and when the sodium hydroxide is too little, the product is in a tetrahedral or spherical shape, because Cu₂The morphology of O mainly depends on the growth rates of the (100) crystal plane and the (111) crystal plane, the plane with the lower growth rate can finally form an exposed plane, and the plane with the high growth rate can finally disappear. When OH is in the reaction solution^-When the concentration is lower, the (100) crystal face grows faster, the final growth morphology is mainly flaky or dendritic, and OH^-The concentration is increased, the growth speed of the (100) crystal face is slowed down, the appearance is mainly octahedron, and OH^-The concentration is further increased, the growth of (111) crystal face is accelerated, the appearance approaches to cube, OH^-At higher concentrations, the (100) and (111) growth rates are close, and the morphology becomes spherical. Hydrazine hydrate is used as reducing agent, and Cu can be added²⁺Reduction to Cu₂Too little O will cause insufficient reaction, while too much will cause further Cu²⁺Reducing the alloy into Cu. In the step B, 200-450 ℃ is selected as the calcining temperature, because PVP can be carbonized to different degrees when calcined at different temperatures, and the carbonized PVP can be used for carbonizing Cu₂O is reduced to Cu. The higher the temperature, the more PVP carbonizes, reducing Cu₂The more Cu is obtained by O, but when the temperature is raised to 450 ℃, the octahedral structure of the calcined product is partially destroyed.

Compared with the prior art, the invention has the following advantages:

the invention utilizes a low-temperature reduction method to rapidly prepare Cu under the ice-water bath condition₂O nano material, exposing the (111) surface with higher catalytic performance, and reducing partial Cu by high-temperature calcination₂O, preparing to obtain octahedral Cu-Cu₂The O composite material can be finished in a common reaction vessel without complex equipment in the whole process, the reaction is carried out in an ice-water bath for controlling the reaction speed, the reaction speed is reduced, the nucleation is facilitated, and therefore a ruler is formedEven octahedral structure. The invention has the advantages of simple process steps, short preparation time, safety, reliability, no generation of toxic or polluted gas, low energy consumption and convenience for expanding production. And the amount of Cu in the composite material prepared by the method can be regulated and controlled by controlling the calcining condition, so that the operation is simple. The octahedron Cu-Cu obtained by preparation₂When the O composite material is used for electrochemical sensing, the Cu in the composite material can effectively improve the conductivity of the material, and has excellent electrocatalytic performance.

Drawings

FIG. 1 shows Cu-Cu prepared in example 1₂XRD pattern of the precursor of the O composite material;

FIG. 2 shows Cu-Cu prepared in example 1₂SEM image of O composite material precursor;

FIG. 3 shows Cu-Cu prepared in example 4₂SEM image of O composite material precursor;

FIG. 4 shows Cu-Cu obtained by calcination at different temperatures₂XRD pattern of O composite;

FIG. 5 shows Cu-Cu obtained by calcination at different temperatures₂SEM image of O composite;

FIG. 6 shows the Cu-Cu obtained by calcining the precursor at different temperatures₂An alternating current impedance plot of the O-composite;

FIG. 7 shows Cu-Cu₂And the O composite material modified electrode has current response curve to glucose NaOH solution with different concentrations.

Detailed Description

The present invention will now be described more fully hereinafter with reference to the accompanying drawings.

Example 1

0.4860 g of Cu (NO) were weighed out₃)₂Dissolved in 200 mL of a PVP (Mw = 58000) solution with a mass fraction of 2%. Placing the reaction container in an ice-water bath, slowly and dropwise adding 3.5 mL of 5 mM NaOH solution and 1.6 mL of 35% hydrazine hydrate solution into the solution under the condition of rapid stirring, reacting until the solution color does not change, and thenStirring is continued for 30 min. Centrifuging the precipitate to obtain a brownish red sample, i.e. Cu-Cu₂And (3) O composite material precursor. The Cu-Cu prepared in this example was used₂Detecting the precursor of the O composite material, and obtaining Cu-Cu shown in figure 1₂XRD (X-ray diffraction) pattern of O composite material precursor, and the spectrogram shows that the sample obtained in the step is Cu₂O, diffraction peaks at 2 θ values of 29.5 °, 36.4 °, 42.3 ° and 61.4 ° correspond to the (110), (111), (200) and (220) crystal planes, respectively. FIG. 2 is Cu₂SEM image of O, from which the Cu produced can be seen₂O has an octahedral structure, is uniform in size and has a smooth surface.

And (3) drying the centrifuged sample at 40-60 ℃ for 10 h in vacuum to obtain brown powder. Then calcining the mixture for 2 hours at 350 ℃ in an argon atmosphere to obtain the Cu-Cu₂And (3) an O composite material.

Example 2

0.4860 g of Cu (NO) were weighed out₃)₂Dissolved in 200 mL of a PVP (Mw = 58000) solution with a mass fraction of 4%. The reaction vessel is placed in an ice-water bath, 3.8mL of NaOH solution with the concentration of 5 mM and 1.6 mL of hydrazine hydrate with the mass fraction of 35% are respectively slowly dripped into the solution under the condition of rapid stirring, the solution is reacted until the color of the solution is not changed, and the stirring is continued for 1 hour. Centrifuging the precipitate to obtain a brownish red sample, i.e. Cu-Cu₂And (3) O composite material precursor.

And (3) carrying out vacuum drying on the sample obtained after centrifugation at the temperature of between 40 and 60 ℃ for 12 hours to obtain brown powder. Then calcining the mixture for 1 hour at 350 ℃ in an argon atmosphere to obtain the Cu-Cu₂And (3) an O composite material.

Example 3

0.4860 g of Cu (NO) were weighed out₃)₂Dissolved in 200 mL of a PVP (Mw = 58000) solution with a mass fraction of 2%. Placing the reaction vessel in an ice-water bath, and respectively adding 2.2mL of the solution with the concentration of 5 under the condition of rapid stirringAnd slowly dripping a mM NaOH solution and 1.6 mL of 35% hydrazine hydrate by mass into the solution, reacting until the color of the solution does not change, and continuing stirring for 2 hours. Centrifuging the precipitate to obtain a brownish red sample, i.e. Cu-Cu₂And (3) O composite material precursor.

Example 4

0.4860 g of Cu (NO) were weighed out₃)₂Dissolved in 200 mL of a PVP (Mw = 58000) solution with a mass fraction of 2%. Placing the reaction container in an ice water bath, slowly and dropwise adding 1 mL of 5 mM NaOH solution and 1.6 mL of 35% hydrazine hydrate solution into the solution under the condition of rapid stirring, reacting until the solution color does not change, and continuing to stir for 30 min. Centrifuging the precipitate to obtain a brownish red sample, i.e. Cu-Cu₂And (3) O composite material precursor. And performing SEM characterization on the product prepared in the step, wherein the obtained substance is flaky in appearance as shown in figure 3.

Example 5

0.4860 g of Cu (NO) were weighed out₃)₂Dissolved in 200 mL of a PVP (Mw = 58000) solution with a mass fraction of 2%. Placing the reaction container in an ice-water bath, slowly and dropwise adding 3.5 mL of 5 mM NaOH solution and 1.6 mL of 35% hydrazine hydrate solution into the solution under the condition of rapid stirring, reacting until the color of the solution does not change, and continuing to stir for 2 h. Centrifuging the precipitate to obtain a brownish red sample, i.e. Cu-Cu₂And (3) O composite material precursor.

And (3) drying the centrifuged sample at 40-60 ℃ for 10 h in vacuum to obtain brown powder. Then calcining for 1h at 240 ℃ in an argon atmosphere to obtain the Cu-Cu₂And (3) an O composite material.

Example 6

Octahedron Cu-Cu₂O complexThe preparation method of the composite material comprises the following steps:

step A: 0.4860 g of Cu (NO) were weighed out₃)₂Dissolved in 200 mL of a PVP (Mw = 58000) solution with a mass fraction of 2%. Placing the reaction container in an ice-water bath, slowly and dropwise adding 3.5 mL of 5 mM NaOH solution and 1.6 mL of 35% hydrazine hydrate solution into the solution under the condition of rapid stirring, reacting until the color of the solution does not change, and continuing to stir for 30 min. Centrifuging the precipitate to obtain a brownish red sample, i.e. Cu-Cu₂And (3) O composite material precursor.

And B: centrifuging the above to obtain Cu-Cu₂And (3) carrying out vacuum drying on the precursor of the O composite material for 12h at the temperature of 60-80 ℃ to obtain brown powder. Then calcining the mixture for 1 hour at 350 ℃ in an argon atmosphere to obtain the Cu-Cu₂And (3) an O composite material.

Example 7

And B: centrifuging the above to obtain Cu-Cu₂And (3) carrying out vacuum drying on the precursor of the O composite material for 12h at the temperature of 60-80 ℃ to obtain brown powder. Then calcining the mixture for 1 hour at 450 ℃ in an argon atmosphere to obtain the Cu-Cu₂And (3) an O composite material.

Cu-Cu prepared in examples 5 to 7₂The O composite material is detected, and Cu-Cu is respectively shown in figure 4 and figure 5₂And calcining the O composite material precursor at 240 ℃, 350 ℃ and 450 ℃ for 1h respectively to obtain XRD (X-ray diffraction) and SEM (scanning Electron microscope) images of the sample. XRD showed that the calcined sample was Cu-Cu₂A complex of O. With increasing temperature, of CuDiffraction peaks were gradually apparent. Wherein diffraction peaks having 2 theta values of 43.3 DEG and 50.5 DEG correspond to (111) and (200) crystal planes of Cu, respectively. It can be seen from the SEM images that the smooth surface of the precursor gradually became rough as the calcination temperature was increased, and the octahedral structure of the calcined product was partially destroyed when the temperature was increased to 450 ℃.

Example 8

This example explores the octahedral Cu-Cu prepared according to the invention₂Use of an O-composite in an electrochemical sensor.

Al for glassy carbon electrode to be used₂O₃Polishing the powder into a mirror surface, cleaning the mirror surface with purified water, then blowing the surface of the electrode with Ar gas, and standing for later use. Respectively taking 8 mg of Cu-Cu₂O precursor and Cu-Cu prepared in examples 5, 6 and 7₂O composite samples were placed in 2mL centrifuge tubes, 0.5 mL purified water and 0.5 mL ethanol were added, and dispersed by sonication. Then 50 uL of Nafion solution was added and sonication continued until a suspension was obtained. Using a liquid transfer gun to absorb 8 uL of sample to be dripped on a glassy carbon electrode which is cleaned and dried by Ar gas, drying for 8-10 h at 40 ℃ in a vacuum drying oven, preparing a precursor and obtaining Cu-Cu under different temperature calcination₂O composite working electrode. The carbon rod and the saturated calomel electrode are respectively used as a counter electrode and a reference electrode to study the surface electron transfer conditions of different working electrodes. FIG. 6 shows the Cu-Cu obtained by calcining the precursor at different temperatures₂The AC impedance of the O composite material is shown in the figure, three types of Cu-Cu₂R of O composite_ctAre all smaller than R of the precursor_ctThe introduction of Cu in the composite material can obviously improve the transfer rate of electrons on the surface of an electrode, thereby increasing the conductivity of the material.

Example 9

Al for glassy carbon electrode to be used₂O₃Polishing the powder into a mirror surface, cleaning the mirror surface with purified water, then blowing the surface of the electrode with Ar gas, and standing for later use. 8 mg of Cu-Cu prepared in example 6 were taken₂O composite samples were placed in 2mL centrifuge tubes, 0.5 mL purified water and 0.5 mL ethanol were added, and dispersed by sonication. Then 50 uL of Nafion solution was added and sonication continued until a suspension was obtained. Sucking 8 uL of sample by using a pipette, dripping the sample on a glassy carbon electrode which is cleaned and dried by Ar gas, and drying the glassy carbon electrode for 8 to 10 hours at 40 ℃ in a vacuum drying oven to obtain the Cu-Cu₂O/GCE. With Cu-Cu₂The O/GCE is used as a working electrode, the carbon rod and the saturated calomel electrode are respectively used as a counter electrode and a reference electrode, and the research on Cu-Cu₂The application of the O composite material in the enzyme-free glucose electrochemical sensing is provided. FIG. 7a is Cu₂Calcining O precursor at 350 ℃ for 1h to obtain Cu-Cu₂The O composite material modified electrode has current response curve to glucose NaOH (0.1M) solution with different concentrations. The current density increases with increasing glucose concentration. As can be seen from FIG. 7b, the current density and the glucose concentration have a good linear relationship in the range of 2 to 1000. mu.M, and the linear correlation coefficient is 0.99967. The detection sensitivity of the electrode modified by the material to glucose is 1.24 mA.mu.M through calculation^-1cm^-2The lowest detectable level was 0.8. mu.M.

The above-mentioned embodiments are merely preferred embodiments of the present invention, which are merely illustrative and not restrictive, and it should be understood that other embodiments may be easily made by those skilled in the art by replacing or changing the technical contents disclosed in the specification, and therefore, all changes and modifications that are made on the principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. Octahedron Cu-Cu₂The preparation method of the O composite material is characterized by comprising the following steps:

step B. mixingStep A obtaining Cu-Cu₂Carrying out vacuum drying on the O precursor material to obtain brown powder, and then calcining at 200-450 ℃ in an argon atmosphere to obtain the Cu-Cu₂And (3) an O composite material.

2. An octahedral Cu-Cu according to claim 1 or 2, of the type₂The preparation method of the O composite material is characterized in that the mass fraction of the PVP solution is 2-5%, and the relative molecular mass of PVP is 58000.

3. The octahedral Cu-Cu of claim 1, wherein₂A method for producing an O composite material, characterized in that the Cu (NO) is₃)₂The molar ratio of hydrazine hydrate to hydrazine hydrate is 1: 5.

4. the octahedral Cu-Cu of claim 1, wherein₂The preparation method of the O composite material is characterized in that Cu (NO) in the step A₃)₂The molar ratio of the NaOH to the NaOH is (100-200): 1.

5. the octahedral Cu-Cu of claim 1, wherein₂The preparation method of the O composite material is characterized in that the continuous stirring time in the step A is 0.5-2 hours.

6. The octahedral Cu-Cu of claim 1, wherein₂The preparation method of the O composite material is characterized in that the temperature of vacuum drying in the step B is 40-60 ℃, and the time is 10-12 h.

7. The octahedral Cu-Cu of claim 1, wherein₂The preparation method of the O composite material is characterized in that the calcination time in the step B is 1-2 h.