CN104562090A - Method for preparing nano-porous copper through in-situ electrolysis of eutectic ionic liquid - Google Patents

Abstract

The invention relates to a method for preparing nanoporous copper by in-situ electrolysis of a deep eutectic ionic liquid, belonging to the technical field of material preparation. In an inert atmosphere, mix the quaternary ammonium salt and amide to prepare a low-eutectic ionic liquid; add an alloy-inducing salt to the low-eutectic ionic liquid and mix evenly to obtain an ionic liquid-alloy salt composite electrolyte; use a copper sheet as a cathode , graphite or inert anode as the anode, the galvanostatic deposition in the obtained ionic liquid-alloy salt composite electrolyte to obtain a homogeneous alloy precursor; under the original electrolyte system, establish a three-electrode system for dealloying, and dealloy The oxidized cathode sheet is washed with absolute ethanol and distilled water, and the copper sheet with nanoporous structure is obtained after drying. The invention has the advantages of mild reaction conditions, controllability, low cost, no pollution, simple process, stable product quality and the like.

Description

A method for preparing nanoporous copper by in-situ electrolysis of eutectic ionic liquid

technical field

The invention relates to a method for preparing nanoporous copper by in-situ electrolysis of a deep eutectic ionic liquid, belonging to the technical field of material preparation.

Background technique

Nanoporous metals refer to materials with pores of nanometer size. Because of its unique bicontinuous nanoporous structure, it has the characteristics of large specific surface area, high strength, good electrical conductivity, and strong catalytic activity. It has a wide range of applications in the fields of sensing, filtration, separation, catalysis, hydrogen storage, electrode materials and surface-enhanced Raman scattering. Compared with noble metal nanoporous materials, nanoporous copper has low production cost, abundant resources, and is suitable for large-scale industrial production.

At present, the methods for preparing nanoporous copper (NPM) mainly include template method and dealloying method. The template method uses nanoporous materials as templates to prepare porous metals by replicating the template structure. Common template methods include: anodic aluminum oxide template method (AAO), polymer template method and hydrogen template method. The nanoporous metal structure obtained by this method depends on the structure of the template itself, which is difficult to adjust; at the same time, the separation operation of the template and the product is easy to cause damage to the structure of the obtained material. Due to the difficulty in controlling the size of the bubbles and the structure of the metal deposition layer on the pore wall in the hydrogen template method, the mechanical properties of nanoporous materials are poor. The dealloying method is to use the potential difference between metals to selectively remove the more active metal components in the alloy in an acid or alkaline environment. Although the dealloying method can prepare nanoporous copper with high porosity and uniform distribution, the key is to obtain a homogeneous alloy precursor with uniform structure and composition. The traditional preparation of homogeneous alloys often requires the metal raw materials to be smelted in a high-frequency induction furnace, annealed and quenched under inert conditions, the production process is complicated, energy consumption is large, and the cost is high; the post-dealloying uses strong corrosive acid or alkali , It takes a long time, and it is easy to cause equipment corrosion and environmental pollution.

The patent application (publication number CN102329977A) announced "a preparation method of enhanced nanoporous copper". Firstly, the alloy ingot was prepared in a vacuum melting furnace and processed into alloy flakes by linear cutting; the alloy flakes were put into NH ₄ Cl-HCl mixed liquid The nanoporous copper can be obtained through the middle reaction; and the enhanced nanoporous copper can be obtained through subsequent operations. The patent application (publication number CN101590528A) announced "a preparation method of nanoporous copper". First, pure Cu and pure Mg are heated to a molten state and cast into an ingot; then the ingot is re-melted to a molten state, and then inert The gas blows the alloy liquid onto a high-speed rotating copper roll or copper mold to prepare a metal alloy strip; finally, dealloying treatment in an acidic liquid can obtain nanoporous copper. The patent application (publication number CN102628112A) announced a "method for preparing three-dimensional network nanoporous copper", which uses arc melting to prepare Cu-Mn alloy, and then uses inert gas to quickly blow out the molten alloy to a high-speed rotating copper roller to prepare alloy Thin strips, and finally put the alloy strips into acid or strong acid and weak alkali salt solution for dealloying to obtain nanoporous copper. The methods for preparing nanoporous copper mentioned above all adopt smelting to prepare alloy precursors + dealloying to prepare nanoporous copper. The disadvantage of this method is that the preparation process is complicated, the smelting process has high requirements on equipment, and the use of strong corrosive acid or alkali in the later stage will cause equipment corrosion, waste of resources, and increase the preparation cost.

The patent application (publication number CN102766893A) announced "a preparation method of patternable nanoporous copper". Developing treatment; using electrodeposition technology to obtain a patterned precursor alloy film; finally putting the precursor alloy film into acid for corrosion and dealloying treatment to obtain nanoporous copper. This method is complicated to prepare, and the number of preparation cycles is relatively large, so it is not suitable for large-scale production. The patent application (publication number CN103357876A) discloses "a preparation method of nanoporous copper film". The pre-prepared organic slurry containing copper powder is coated on the surface of the substrate, and the nanoporous copper film can be obtained after heat treatment. The unsupported nanoporous copper membrane was obtained by corroding the support with hydrochloric acid. Although this method is simple and the cost is low, the quality of the obtained porous copper is poor, and the size and uniformity of the pores are difficult to control.

Deep eutectic solvents are usually eutectic mixtures composed of certain stoichiometric ratios of quaternary ammonium salts and hydrogen bond donors (such as compounds such as amides, carboxylic acids, and polyols). The deep eutectic solvent has the advantages of good solubility and conductivity, low vapor pressure and good physical and chemical stability. The synthetic raw material is cheap, the production process is simple, and the product with high purity can be obtained without purification. It is a new type of solvent. Green solvent. Compared with traditional aqueous solutions and organic solvents, deep eutectic ionic liquids provide a chemical environment different from traditional molecular solvents, without protons, strong polarity, faster nucleation rate of substances, and easy to form order under the action of hydrogen bonds Structure, high chemical and thermal stability, when the operating temperature is 100-150 ℃, it can be electrodeposited to prepare homogeneous alloys. Therefore, using eutectic ionic liquid as a solvent medium, nanoporous metal materials can be prepared by electrodeposition alloy-in-situ dealloying, so as to solve the complex process, high energy consumption, low efficiency and serious equipment corrosion of traditional preparation methods. , high cost and a series of problems.

Contents of the invention

Aiming at the problems and deficiencies in the existing methods for preparing nanoporous copper, the present invention provides a method for preparing nanoporous copper by in-situ electrolysis using pure copper as a matrix in a low-eutectic ionic liquid. The invention has the advantages of mild reaction conditions, controllability, low cost, no pollution, simple process, stable product quality, etc., and the invention is realized through the following technical solutions.

The technical route provided by the present invention is: use low-eutectic ionic liquid as solvent, introduce alloy induction salt (zinc oxide or zinc chloride) into it, use copper sheet as cathode, graphite or inert anode as anode, open system Prepared by electrolysis.

A method for preparing nanoporous copper by in-situ electrolysis of eutectic ionic liquid, the specific steps are as follows:

(1) Under an inert atmosphere, dry the quaternary ammonium salt and amide in a vacuum at 80°C and mix them according to the molar ratio of 1:(1~4). Under the condition of constant temperature heating at 80°C, react for 1 hour to prepare the eutectic type Ionic liquid; adding an alloy-inducing salt to the low-eutectic ionic liquid and mixing uniformly to obtain an ionic liquid-alloy salt composite electrolyte;

(2) Use copper sheet as cathode, graphite or inert anode as anode, in the ionic liquid-alloy salt composite electrolyte obtained in step (1) at a temperature of 80~150°C, without stirring, and with a cathode current density of 0.20~2mAcm Constant current deposition under ^-2 conditions for 0.50~2h to obtain a homogeneous alloy precursor;

(3) Under the original electrolyte system, a three-electrode system is established, with the alloy precursor as the working electrode, the graphite or inert anode as the counter electrode, and the silver wire as the reference electrode, and the homogeneous alloy obtained in step (2) Control the potential of -0.50~-0.20Vvs.Ag in the precursor for dealloying, wash the dealloyed cathode sheet with absolute ethanol and distilled water, and obtain a copper sheet with a nanoporous structure after drying.

The quaternary ammonium salt in the step (1) is choline chloride, acetylcholine chloride or tetramethylammonium chloride.

The amide in the step (1) is urea, dimethylformamide or acetamide.

In the step (1), the alloy-inducing salt is zinc oxide or zinc chloride, and the mass ratio of the volume of the low-eutectic ionic liquid to the alloy-inducing salt is 100:(200-2500) mL/mg.

The beneficial effects of the present invention are: (1) the preparation of the alloy precursor by electrodeposition and the post-dealloying can be completed in the same electrolytic system by adopting the method; (2) the size of the prepared nanoporous copper voids is uniform and controllable; (3 ) does not involve corrosive acid or alkali, the reaction conditions are mild, and the reaction energy consumption is low; (4) cheap, pollution-free, simple and recyclable process, and stable product quality.

Description of drawings

Fig. 1 is the SEM picture of the product obtained by electrolysis in Example 1 of the present invention when the magnification is 10000 times;

Fig. 2 is the SEM picture of the product obtained by electrolysis in Example 1 of the present invention when the magnification is 50000 times;

Fig. 3 is the SEM picture of the product obtained by electrolysis in Example 2 of the present invention when the magnification is 50000 times;

Fig. 4 is a SEM image of the product prepared by electrolysis in Example 3 of the present invention at a magnification of 50,000 times.

Detailed ways

The present invention will be further described below in combination with the accompanying drawings and specific embodiments.

Example 1

The method for preparing nanoporous copper by in-situ electrolysis of the eutectic ionic liquid, the specific steps are as follows:

(1) Under an inert atmosphere, the quaternary ammonium salt and the amide are mixed according to the molar ratio of 1:2 after being vacuum-dried at 80°C, and the low-eutectic ionic liquid can be prepared by reacting for 1 hour under the condition of constant temperature heating at 80°C; Add 0.150g alloy-inducing salt (the alloy-inducing salt is zinc chloride, and the mass ratio of the volume of the low-eutectic ionic liquid to the alloy-inducing salt is 100:750mL/mg) into 20mL low-eutectic ionic liquid and mix evenly to obtain ions Liquid-alloy salt composite electrolyte; the quaternary ammonium salt is choline chloride, and the amide is urea;

(2) Use copper sheet (2.0cm×1.5cm×0.1cm) as cathode, graphite as anode, and silver wire as reference electrode, in the 20mL ionic liquid-alloy salt composite electrolyte obtained in step (1) and at temperature galvanostatic deposition for 1 h under the conditions of 120°C, 1 cm electrode spacing, no stirring, and 1 mA cm ^-2 cathode current density, to obtain a homogeneous Cu-Zn alloy precursor;

(3) Under the original electrolyte system, a three-electrode system is established, with the alloy precursor as the working electrode, graphite as the counter electrode, and silver wire as the reference electrode. In the homogeneous alloy precursor obtained in step (2), Control potential -0.30Vvs.Ag dealloying, wash the dealloyed cathode sheet with absolute ethanol and distilled water, and obtain copper sheet with nanoporous structure after drying. The SEM image of the prepared nanoporous copper at a magnification of 10,000 times is shown in FIG. 1 and the SEM image at a magnification of 50,000 times is shown in FIG. 2 .

Example 2

The method for preparing nanoporous copper by in-situ electrolysis of the eutectic ionic liquid, the specific steps are as follows:

(1) Under an inert atmosphere, the quaternary ammonium salt and the amide are mixed according to a molar ratio of 1:3 after being vacuum-dried at 80°C, and the low-eutectic ionic liquid can be prepared by reacting for 1 hour under the condition of constant temperature heating at 80°C; Add 0.200g alloy-inducing salt (the alloy-inducing salt is zinc oxide, and the mass ratio of the volume of the low-eutectic ionic liquid to the alloy-inducing salt is 100:1000mL/mg) into 20mL low-eutectic ionic liquid and mix evenly to obtain an ionic liquid -alloy salt composite electrolyte; wherein the quaternary ammonium salt is acetylcholine chloride, and the amide is dimethylformamide;

(2) Use copper sheet (2.0cm×1.5cm×0.1cm) as cathode, graphite as anode, and silver wire as reference electrode, in the 20mL ionic liquid-alloy salt composite electrolyte obtained in step (1) and at temperature Constant current deposition for 0.5h under the conditions of 100°C, electrode spacing of 1cm, no need for stirring, and cathode current density of 0.5mAcm ^-2 , to obtain a homogeneous Cu-Zn alloy precursor;

(3) Under the original electrolyte system, a three-electrode system is established, with the alloy precursor as the working electrode, the graphite or inert anode as the counter electrode, and the silver wire as the reference electrode, and the homogeneous alloy obtained in step (2) Control the potential of -0.50Vvs.Ag in the precursor for dealloying, wash the dealloyed cathode sheet with absolute ethanol and distilled water, and obtain a copper sheet with a nanoporous structure after drying. The SEM image of the prepared nanoporous copper at a magnification of 50,000 times is shown in FIG. 3 .

Example 3

The method for preparing nanoporous copper by in-situ electrolysis of the eutectic ionic liquid, the specific steps are as follows:

(1) Under an inert atmosphere, the quaternary ammonium salt and the amide are mixed according to the molar ratio of 1:2 after being vacuum-dried at 80°C, and the low-eutectic ionic liquid can be prepared by reacting for 1 hour under the condition of constant temperature heating at 80°C; Add 0.350g of alloy-inducing salt (the alloy-inducing salt is zinc chloride, and the mass ratio of the volume of the low-eutectic ionic liquid to the alloy-inducing salt is 100:1750mL/mg) into 20mL low-eutectic ionic liquid and mix evenly to obtain ions Liquid-alloy salt composite electrolyte; the quaternary ammonium salt is acetylcholine chloride, and the amide is urea;

(2) Use copper sheet (2.0cm×1.5cm×0.1cm) as cathode, graphite as anode, and silver wire as reference electrode, in the 20mL ionic liquid-alloy salt composite electrolyte obtained in step (1) and at temperature Constant current deposition for 0.5h under the conditions of 150°C, electrode spacing of 1cm, no stirring, and cathode current density of 1mAcm ^-2 , to obtain a homogeneous Cu-Zn alloy precursor;

(3) Under the original electrolyte system, a three-electrode system is established, with the alloy precursor as the working electrode, the graphite or inert anode as the counter electrode, and the silver wire as the reference electrode, and the homogeneous alloy obtained in step (2) Control the potential of -0.40Vvs.Ag in the precursor for dealloying, rinse the dealloyed cathode sheet with absolute ethanol and distilled water, and obtain a copper sheet with a nanoporous structure after drying. The SEM image of the prepared nanoporous copper at a magnification of 50,000 times is shown in FIG. 4 .

Example 4

The method for preparing nanoporous copper by in-situ electrolysis of the eutectic ionic liquid, the specific steps are as follows:

(1) Under an inert atmosphere, the quaternary ammonium salt and the amide are mixed according to the molar ratio of 1:2 after being vacuum-dried at 80°C, and the low-eutectic ionic liquid can be prepared by reacting for 1 hour under the condition of constant temperature heating at 80°C; Add 0.100g alloy-inducing salt (the alloy-inducing salt is zinc oxide, and the mass ratio of the volume of the low-eutectic ionic liquid to the alloy-inducing salt is 100:500mL/mg) into 20mL low-eutectic ionic liquid and mix evenly to obtain an ionic liquid -alloy salt composite electrolyte; wherein the quaternary ammonium salt is tetramethylammonium chloride, and the amide is acetamide;

(2) Use copper sheet (2.0cm×1.5cm×0.1cm) as cathode, graphite as anode, and silver wire as reference electrode, in the 20mL ionic liquid-alloy salt composite electrolyte obtained in step (1) and at temperature Constant current deposition for 1 h under the conditions of 100 ℃, electrode spacing of 1 cm, no need for stirring, and cathode current density of 2 mAcm ^-2 to obtain a homogeneous Cu-Zn alloy precursor;

(3) Under the original electrolyte system, a three-electrode system is established, with the alloy precursor as the working electrode, the graphite or inert anode as the counter electrode, and the silver wire as the reference electrode, and the homogeneous alloy obtained in step (2) Control the potential of -0.30Vvs.Ag in the precursor for dealloying, wash the dealloyed cathode sheet with absolute ethanol and distilled water, and obtain a copper sheet with a nanoporous structure after drying.

Example 5

The method for preparing nanoporous copper by in-situ electrolysis of the eutectic ionic liquid, the specific steps are as follows:

(1) Under an inert atmosphere, the quaternary ammonium salt and the amide are mixed according to a molar ratio of 1:1 after being vacuum-dried at 80°C, and the low-eutectic ionic liquid can be prepared by reacting for 1 hour under constant temperature heating at 80°C; Add 0.500g of alloy-inducing salt (the alloy-inducing salt is zinc chloride, and the mass ratio of the volume of the low-eutectic ionic liquid to the alloy-inducing salt is 100:2500mL/mg) into 20mL low-eutectic ionic liquid and mix evenly to obtain ions Liquid-alloy salt composite electrolyte; the quaternary ammonium salt is tetramethylammonium chloride, and the amide is acetamide;

(2) Use copper sheet (2.0cm×1.5cm×0.1cm) as cathode, graphite as anode, and silver wire as reference electrode, in the 20mL ionic liquid-alloy salt composite electrolyte obtained in step (1) and at temperature Constant current deposition for 2 hours under the conditions of 80°C, electrode spacing of 1cm, no need for stirring, and cathode current density of 0.2mAcm ^- 2, to obtain a homogeneous Cu-Zn alloy precursor;

(3) Under the original electrolyte system, a three-electrode system is established, with the alloy precursor as the working electrode, the graphite or inert anode as the counter electrode, and the silver wire as the reference electrode, and the homogeneous alloy obtained in step (2) Control the potential of -0.20Vvs.Ag in the precursor for dealloying, rinse the dealloyed cathode sheet with absolute ethanol and distilled water, and obtain a copper sheet with a nanoporous structure after drying.

Example 6

The method for preparing nanoporous copper by in-situ electrolysis of the eutectic ionic liquid, the specific steps are as follows:

(1) Under an inert atmosphere, the quaternary ammonium salt and the amide are mixed according to the molar ratio of 1:4 after being vacuum-dried at 80°C, and the low-eutectic ionic liquid can be prepared by reacting for 1 hour under the condition of constant temperature heating at 80°C; Add 0.04g alloy-inducing salt (the alloy-inducing salt is zinc oxide, and the mass ratio of the volume of the low-eutectic ionic liquid to the alloy-inducing salt is 100:200mL/mg) into 20mL low-eutectic ionic liquid and mix evenly to obtain an ionic liquid -alloy salt composite electrolyte; wherein the quaternary ammonium salt is acetylcholine chloride, and the amide is acetamide;

(2) Use copper sheet (2.0cm×1.5cm×0.1cm) as cathode, graphite as anode, and silver wire as reference electrode, in the 20mL ionic liquid-alloy salt composite electrolyte obtained in step (1) and at temperature Constant current deposition for 0.8h under the conditions of 80°C, electrode spacing of 1cm, no need for stirring, and cathode current density of 2mAcm ^-2 , to obtain a homogeneous Cu-Zn alloy precursor;

(3) Under the original electrolyte system, a three-electrode system is established, with the alloy precursor as the working electrode, the graphite or inert anode as the counter electrode, and the silver wire as the reference electrode, and the homogeneous alloy obtained in step (2) Control the potential of -0.25Vvs.Ag in the precursor for dealloying, wash the dealloyed cathode sheet with absolute ethanol and distilled water, and obtain a copper sheet with a nanoporous structure after drying.

The specific implementation of the present invention has been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned implementation, within the knowledge of those of ordinary skill in the art, it can also be made without departing from the gist of the present invention. Variations.

Claims (4)

1. eutectic type ionic liquid in-situ electrolysis prepares a method for nano porous copper, it is characterized in that concrete steps are as follows:

(1) under an inert atmosphere, by quaternary ammonium salt and acid amides after 80 DEG C of vacuum-drying according to mol ratio 1:(1 ~ 4) mix, under 80 DEG C of thermostatically heating conditions, reaction 1h can prepare low melt type ionic liquid altogether; In low altogether melt type ionic liquid, add alloy induction salt mix and obtain ionic liquid-alloy salts composite electrolytic solution;

(2) make negative electrode with copper sheet, graphite or inert anode make anode, in ionic liquid-alloy salts composite electrolytic solution that step (1) obtains and temperature be 80 ~ 150 DEG C, without the need to stirring, cathode current density 0.20 ~ 2mAcm ^-2galvanostatic deposition 0.50 ~ 2h under condition, obtains the alloy presoma of homogeneous phase;

(3) under original electrolyte system, set up three-electrode system, with alloy presoma for working electrode, graphite or inert anode are to electrode, filamentary silver is reference electrode, controlling potential-0.50 ~-0.20Vvs.Ag removal alloying in the alloy presoma of the homogeneous phase obtained in step (2), by the cathode sheets of removal alloying through dehydrated alcohol, distilled water flushing, namely obtains the copper sheet with nano-porous structure after drying.

2. eutectic type ionic liquid in-situ electrolysis according to claim 1 prepares the method for nano porous copper, it is characterized in that: the quaternary ammonium salt in described step (1) is choline chloride 60, Acetylcholine Chloride or tetramethyl ammonium chloride.

3. eutectic type ionic liquid in-situ electrolysis according to claim 1 prepares the method for nano porous copper, it is characterized in that: the acid amides in described step (1) is urea, dimethyl formamide or ethanamide.

4. eutectic type ionic liquid in-situ electrolysis according to claim 1 prepares the method for nano porous copper, it is characterized in that: described step (1) interalloy induction salt is zinc oxide or zinc chloride, volume and the alloy of low melt type ionic liquid altogether induce the mass ratio of salt to be 100:(200 ~ 2500) mL/mg.