WO2015196866A1

WO2015196866A1 - Method for preparing cuprous oxide

Info

Publication number: WO2015196866A1
Application number: PCT/CN2015/077830
Authority: WO
Inventors: 刘少军; 张宏生; 王莉; 尚玉明; 何向明; 李建军; 王要武; 高剑; 罗晶
Original assignee: 江苏华东锂电技术研究院有限公司; 清华大学
Priority date: 2014-06-27
Filing date: 2015-04-29
Publication date: 2015-12-30
Also published as: CN104098121A

Abstract

The present invention relates to a method for preparing cuprous oxide, comprising the following steps: mixing and dissolving bivalent copper source in a solvothermal reaction medium to obtain the first mixture solution, wherein the solvothermal reaction medium comprises water and organic solvent; regulating the pH value of the first mixture solution into the range of 8 to 12; and subjecting the pH value-regulated first mixture solution to a solvothermal reaction; thereby obtaining a reaction product cuprous oxide.

Description

Preparation method of cuprous oxide

Technical field

The invention relates to a preparation method of a cuprous oxide nano material, in particular to a preparation method of a controlled shape of cuprous oxide.

Background technique

Nanomaterials generally refer to materials that have at least one dimension in the three-dimensional space in the nanometer scale or are composed of them as basic units. According to the dimension, nanomaterials can be divided into four categories: zero-dimensional, one-dimensional, two-dimensional and three-dimensional. Nanomaterials have four distinct effects: small size effects, surface effects, quantum size effects, and macroscopic quantum tunneling effects, which have distinct physicochemical properties compared to conventional materials.

Cuprous oxide (Cu ₂ O) is a very important inorganic compound and is a typical p-type semiconductor with a band gap energy of 2.0 eV to 2.2 eV at room temperature. It has a wide range of applications in the fields of photocatalysis, solar cells, biosensing, gas sensing, magnetic storage devices, coatings and lithium ion batteries, and has attracted widespread attention from researchers at home and abroad. At present, the research on Cu ₂ O mainly focuses on the synthesis method and the control of the morphology structure.

In the prior art, a certain surfactant PVP is added to a soluble copper salt solution, and then a certain hydrated hydrazine is added as a reducing agent to prepare a cuprous oxide hollow sphere having a diameter of 100 to 300 nm. In addition, polyethylene oxide as a solvent, sodium dodecylbenzenesulfonate as a surfactant, and hydrazine hydrate as a reducing agent were also prepared, and a cuprous oxide open hollow sphere was prepared. Although these preparation methods have their own advantages, the cuprous oxide crystals with special morphology are synthesized, but the surfactants need to be added as a template, and the reducing agent hydrazine hydrate is more toxic, and the environmental pollution problem needs to be solved.

Summary of the invention

In view of this, it is indeed necessary to provide a method for preparing a cuprous oxide nanomaterial which does not require the addition of a surfactant, is environmentally friendly, and has a controlled morphology.

A method for preparing cuprous oxide, comprising the steps of: mixing and dissolving a source of divalent copper in a solvothermal reaction medium to form a first mixed solution, the solvothermal reaction medium comprising water and an organic solvent; adjusting the first The pH of the mixed solution is in the range of 8 to 12, and the pH-adjusted first mixed solution is subjected to a solvothermal reaction to obtain a reaction product cuprous oxide.

Compared with the prior art, the embodiment of the present invention utilizes mixing of water and an organic solvent as a solvothermal reaction medium, and by adjusting the pH of the solvothermal reaction raw material to be alkaline, uniform size, non-agglomeration, large specific surface area, and shape can be prepared. Controllable monodisperse nanocrystals. The method can realize the controllable preparation of the cuprous oxide nanomaterial from one-dimensional to three-dimensional. In addition, the preparation process is simple, and no dispersant and surfactant are added, thereby avoiding the adverse effect of the addition of the dispersant and the surfactant on the crystal morphology. In addition, the preparation method has high yield, low production cost, and is easy to realize industrial production.

DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a scanning electron micrograph of a cuprous oxide hollow sphere synthesized in Example 1 of the present invention.

2 is a scanning electron micrograph of a cuprous oxide hollow sphere synthesized in Example 2 of the present invention.

3 is a scanning electron micrograph of a cuprous oxide nanosheet synthesized in Example 3 of the present invention.

4 is a scanning electron micrograph of a cuprous oxide nanoparticle synthesized in Example 4 of the present invention.

The invention will be further illustrated by the following detailed description in conjunction with the accompanying drawings.

detailed description

The preparation method of cuprous oxide provided by the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

Embodiments of the present invention provide a method for preparing cuprous oxide, comprising the following steps:

S1, mixing and dissolving a source of divalent copper in a solvothermal reaction medium to form a first mixed solution, the solvothermal reaction medium comprising water and an organic solvent;

S2, adjusting the pH of the first mixed solution to be in the range of 8 to 12, and

S3, the pH-adjusted first mixed solution is subjected to a solvothermal reaction to obtain a reaction product cuprous oxide.

In the above step S1, the divalent copper source is soluble in the solvothermal reaction medium. The divalent copper source may be at least one of copper nitrate (Cu(HO ₃ ) ₂ ), copper chloride (CuCl ₂ ), and copper sulfate (CuSO ₄ ). The divalent copper source may have a molar content of from 0.2 mmol to 30 mmol. The morphology of the cuprous oxide can be controlled by controlling the molar content of the divalent copper source, the larger the molar content of the divalent copper source, the easier it is to form a solid spherical cuprous oxide. Preferably, the divalent copper source has a molar content of from 0.2 mmol to 5 mmol.

The solvothermal reaction medium is a mixture of the water and an organic solvent. The water and the organic solvent are uniformly mixed with each other. The water may be distilled water. The volume of the water may range from 3 ml to 32 ml. The volume of the organic solvent may range from 3 ml to 32 ml. The organic solvent is preferably a polyol having reducing properties. Due to the reducibility, the organic solvent can reduce divalent copper to monovalent copper, so that no strong reducing agent is added during the preparation of cuprous oxide, which is environmentally friendly and simple in process. The polyol may be a water-miscible alcohol such as one or more of diethylene glycol, glycerol, triethylene glycol, tetraethylene glycol, and butyl triol. Preferably, the organic solvent is sparingly soluble or insoluble with water, i.e., the organic solvent has a lower solubility in water. The uniform mixture of the organic solvent having a lower solubility in water and water is used as the solvothermal reaction medium to facilitate the control of the morphology of the cuprous oxide formed. The organic solvent having a low solubility in water may preferably be a reducing polyol such as at least one of n-butanol, isobutanol, n-pentanol, n-hexanol, and n-heptanol. The use of such polyols can effectively control the morphology of cuprous oxide. Preferably, the organic solvent is isobutanol.

The volume ratio of the water to the organic solvent may be from 15:1 to 1:12. The morphology of the subsequently formed cuprous oxide can be controlled and controlled by using the solvothermal reaction medium in the volume ratio range. Preferably, the volume ratio of the water to the organic solvent may be from 10:1 to 1:2. Different morphology of cuprous oxide can be formed by controlling the volume ratio of the water to the organic solvent. Specifically, the step S1 further comprises adjusting the volume ratio of the water to the organic solvent to be less than 0.1:1 to form one-dimensional cuprous oxide nanoparticles. The volume ratio of the water to the organic solvent is adjusted to be 0.1 to 0.2:1 to form a one-dimensional cuprous oxide nanorod. The volume ratio of the water to the organic solvent is adjusted to be 0.2 to 0.5:1 to form a two-dimensional cuprous oxide nanosheet. The volume ratio of the water to the organic solvent is adjusted to be 0.5 to 10:1 to form a two-dimensional cuprous oxide nano hollow sphere.

Preferably, in the above step S1, the step of forming the first mixed solution further comprises:

S11, adding the source of divalent copper to the water to mix and dissolve to form an aqueous solution of copper source, and

S12, adding the organic solvent to the copper source aqueous solution to mix and dissolve to form the first mixed solution.

In the above step S12, the organic solvent may be uniformly mixed with the copper source aqueous solution in a manner of stirring, and the organic solvent may be maximized in the copper source aqueous solution. The stirring speed may be from 100 r/min to 3000 r/min, and the stirring time may be from 0.5 hours to 2 hours. The stirring can be carried out at room temperature. The first mixed solution is a clear transparent solution. A better solvothermal reaction raw material can be obtained by the above mixing method of S11-S12, thereby facilitating the control of the product morphology.

In the above step S2, a pH adjusting agent may be employed to adjust the pH of the first mixed solution. The pH adjuster is an alkaline solution, and preferably, the pH adjuster may be at least one of ammonia water, sodium hydroxide, and potassium hydroxide. More preferably, the pH adjusting agent is aqueous ammonia. The morphology and crystallinity of the formed cuprous oxide can be effectively controlled by previously adjusting the pH of the first mixed solution to be alkaline. The pH adjuster may preferably be gradually added to the first mixed solution to adjust the pH of the first mixed solution to be uniform and sufficient. The volume adjusting agent may have a volume percentage in the first mixed liquid of 0.1% to 15%.

The above step S2 may further comprise a step of stirring to uniformly mix the pH adjuster with the first mixed solution. In this step, the stirring rate may be 100 r/min to 3000 r/min, and the stirring time may be 0.5 hour to 2 hours.

In the above step S3, the solvothermal reaction is carried out in a high pressure reactor at a temperature of from 100 ° C to 240 ° C. The solvothermal reaction vessel may be a sealed autoclave, and the internal pressure of the reactor is raised under the high temperature and high pressure condition by pressurizing the sealed autoclave or using the autogenous pressure of the steam inside the reactor to raise the internal pressure of the reactor. Carry out the reaction. The internal pressure of the reactor may be 0.2 MPa to 30 MPa, and the reaction time is 2 hours to 40 hours, and the reaction product cuprous oxide is obtained. After the reaction is completed, the reaction vessel can be naturally cooled to room temperature.

Further, after the reaction product is obtained by the step S3, the reaction product can be further separated and purified. The manner of separation can be filtration or centrifugation. In the embodiment of the present invention, the reaction product is separated by centrifugal separation, and the rotational speed of the centrifugal separation may be 3000r/min to 8000r/min. The separated reaction product can be further washed. In the examples of the present invention, the reaction product is washed several times with water and absolute ethanol, respectively.

The separated and purified reaction product may be further dried to remove the solvent. The drying can be vacuum filtration or heat drying. The heating and drying temperature may be 60 ° C to 80 ° C, and the heating time may be 12 hours to 24 hours.

One-dimensional to three-dimensional cuprous oxide nanocrystals with different morphologies can be prepared by the above method, including nanoparticles, nanorods, nanosheets, nano hollow spheres, and nano solid spheres.

In the embodiment of the present invention, a mixture of water and an organic solvent is used as a solvothermal reaction medium, and a monodisperse nanometer having uniform size, non-agglomeration, large specific surface area and controllable morphology can be prepared by adjusting the pH of the solvothermal reaction raw material to be alkaline. Crystal. The method can realize the controllable preparation of the cuprous oxide nanomaterial from one-dimensional to three-dimensional. In addition, the preparation process is simple, and no dispersant and surfactant are added, thereby avoiding the adverse effect of the addition of the dispersant and the surfactant on the crystal morphology. In addition, the preparation method has high yield, low production cost, and is easy to realize industrial production.

Example 1

3 mmol of copper nitrate was weighed and dissolved in 30 ml of pure water to form a stable aqueous solution of copper nitrate. Adding a volume of 5 ml of isobutanol to the prepared aqueous solution of copper nitrate, and stirring at a stirring speed of 400 r/min for 1 hour to obtain the first mixed solution; and further measuring 1 mL of aqueous ammonia to be added dropwise to the above prepared solution. The first mixed solution was stirred at a stirring speed of 300 r/min for 0.5 hour to adjust the pH of the first mixed solution; the pH-adjusted first mixed solution was sealed in an autoclave having a polytetrafluoroethylene liner. The temperature was kept at a reaction temperature of 200 ° C for 10 hours, and naturally cooled to room temperature; washed 5 times with distilled water, washed 5 times with absolute ethanol, and then centrifuged at a rotational speed of 4000 r / min for 3 minutes to obtain wet cuprous oxide. The wet cuprous oxide was placed in a vacuum drying oven and dried at 80 ° C for 20 hours, and the obtained brick red powder was a cuprous oxide crystal.

Referring to FIG. 1, it can be seen that the cuprous oxide crystal is a monodisperse three-dimensional hollow sphere, and the three-dimensional hollow sphere is self-assembled by cuprous oxide nanorods or nanosheets. The three-dimensional hollow sphere has a diameter of about 5 μm.

Example 2

Weigh 3 mmol of copper nitrate, dissolve it in 31 ml of pure water to form a stable aqueous solution of copper nitrate; add 4 ml of isobutanol to the prepared aqueous solution of copper nitrate, and stir for 0.5 hour at a stirring speed of 100 r / min. The first mixed solution was obtained; another 1 mL of ammonia water was added dropwise to the prepared first mixed solution, and the pH of the first mixed solution was adjusted by stirring at a stirring speed of 400 r/min for 0.5 hour. The pH-adjusted first mixed solution was sealed in an autoclave having a polytetrafluoroethylene liner, kept at a constant temperature of 190 ° C for 8 hours, and naturally cooled to room temperature; washed with distilled water 5 times, absolute ethanol The mixture was washed 5 times, and then centrifuged at a rotational speed of 8000 r/min for 3 minutes to obtain wet cuprous oxide. The wet cuprous oxide was placed in a vacuum drying oven and dried at 80 ° C for 20 hours, and the obtained brick red powder was a cuprous oxide crystal.

Referring to Figure 2, it can be seen that the cuprous oxide crystals are monodisperse three-dimensional hollow spheres, which are denser than the crystals obtained in Example 1, indicating that an increase in the proportion of water facilitates the formation of dense hollow spheres.

Example 3

2 mmol of copper nitrate was weighed and dissolved in 7 ml of pure water to form a stable aqueous solution of copper nitrate; 28 ml of isobutanol was added to the prepared aqueous solution of copper nitrate, and stirred at a stirring speed of 500 r/min for 2 hours. The first mixed solution is obtained; another 1 mL of ammonia water is added dropwise to the first mixed solution prepared above, and the pH of the first mixed solution is adjusted by stirring at a stirring speed of 50 r/min for 0.5 hour. . The pH-adjusted first mixed solution was sealed in an autoclave having a polytetrafluoroethylene liner, kept at a reaction temperature of 220 ° C for 30 hours, and naturally cooled to room temperature; washed with distilled water 5 times, absolute ethanol The mixture was washed 5 times, and then centrifuged at 3000 r/min for 3 minutes to obtain wet cuprous oxide. The wet cuprous oxide was placed in a vacuum drying oven and dried at 80 ° C for 20 hours, and the obtained brick red powder was a cuprous oxide crystal.

Referring to FIG. 3, it can be seen that the cuprous oxide crystal is a monodisperse nanosheet having a thickness of several tens of nanometers.

Example 4

2 mmol of copper nitrate was weighed and dissolved in 3 ml of pure water to form a stable aqueous solution of copper nitrate; a volume of 32 ml of isobutanol was added to the prepared aqueous solution of copper nitrate, and stirred at a stirring speed of 200 r/min for 1 hour. The first mixed solution is obtained. Further, 1 mL of ammonia water was added dropwise to the above-prepared first mixed solution, and stirred at a stirring speed of 250 r/min for 0.5 hour to adjust the pH of the first mixed solution. The pH-adjusted first mixed solution was sealed in an autoclave having a polytetrafluoroethylene liner, kept at a reaction temperature of 240 ° C for 40 hours, naturally cooled to room temperature, and washed 5 times with distilled water, The water ethanol was washed 5 times, and then centrifuged at a rotational speed of 5000 r/min for 3 minutes to obtain wet cuprous oxide. The wet cuprous oxide was placed in a vacuum drying oven and dried at 80 ° C for 20 hours, and the obtained brick red powder was a cuprous oxide crystal.

Referring to FIG. 4, it can be seen that the cuprous oxide crystal is a monodisperse nanoparticle having a diameter of several tens of nanometers.

In addition, those skilled in the art can make other changes in the spirit of the present invention. Of course, the changes made in accordance with the spirit of the present invention should be included in the scope of the present invention.

Claims

A method for preparing cuprous oxide, comprising the steps of:

The divalent copper source is mixed and dissolved in a solvothermal reaction medium to form a first mixed solution, the solvothermal reaction medium comprising water and an organic solvent;

Adjusting the pH of the first mixed solution within a range of 8 to 12, and

The pH-adjusted first mixed solution is subjected to a solvothermal reaction to obtain a reaction product cuprous oxide.
The method for producing cuprous oxide according to claim 1, wherein a volume ratio of water to the organic solvent in the solvothermal reaction medium is from 15:1 to 1:12.
A method of producing cuprous oxide according to claim 2, wherein a volume ratio of said water to said organic solvent is adjusted to be less than 0.1:1 to form cuprous oxide nanoparticles.
The method for producing cuprous oxide according to claim 2, wherein a volume ratio of the water to the organic solvent is adjusted to be 0.1 to 0.2:1 to form a one-dimensional cuprous oxide nanorod.
The method for producing cuprous oxide according to claim 2, wherein a volume ratio of the water to the organic solvent is adjusted to be 0.2 to 0.5:1 to form a two-dimensional cuprous oxide nanosheet.
The method for preparing cuprous oxide according to claim 2, wherein the volume ratio of the water to the organic solvent is adjusted to be 0.5 to 10:1 to form a three-dimensional cuprous oxide nano hollow sphere.
The method for producing cuprous oxide according to claim 1, wherein the organic solvent is a polyhydric alcohol having a reducing property.
The method for producing cuprous oxide according to claim 1, wherein the organic solvent is uniformly mixed with water and is a polyol which is sparingly soluble or insoluble with water.
The method for producing cuprous oxide according to claim 8, wherein the organic solvent is at least one of n-butanol, isobutanol, n-pentanol, n-hexanol, and n-heptanol.
The method for preparing cuprous oxide according to claim 1, wherein a pH adjusting agent is used to adjust a pH of said first mixed solution, said pH adjusting agent being ammonia water, sodium hydroxide, and potassium hydroxide. At least one of them.