WO2018024181A1

WO2018024181A1 - Method for preparing graphene foam metal for carrying titanium dioxide-precious metal thin film

Info

Publication number: WO2018024181A1
Application number: PCT/CN2017/095363
Authority: WO
Inventors: 杨与畅
Original assignee: 福建新峰二维材料科技有限公司
Priority date: 2016-08-01
Filing date: 2017-08-01
Publication date: 2018-02-08
Also published as: CN107675219A

Abstract

A method for preparing graphene foam metal for carrying a titanium dioxide-precious metal thin film. The method comprises: preparing an electrolyte containing titanium dioxide; cleaning to-be-electroplated foam metal whose surface is deposited with graphene; placing the graphene foam metal into the electrolyte to carry out electrochemical deposition, the electrochemical deposition being carried out by using an electrochemical workstation, the electrochemical workstation comprising a working electrode, a counter electrode, a reference electrode and an electrolytic cell, the working electrode being foam metal to be electroplated, the counter electrode being a platinum electrode, the reference electrode being a saturated calomel electrode, and the electrolyte being placed in the electrolytic cell; cleaning and drying the electrochemically-deposited graphene foam metal for carrying a titanium dioxide-precious metal thin film; and sintering the cleaned and dried graphene foam metal for carrying a titanium dioxide-precious metal thin film. The graphene foam metal for carrying a titanium dioxide-precious metal thin film prepared by using the method effectively prolongs the service life of a carrier generated by using a photocatalytic film, and prevents recombination of a hole and electrons.

Description

Method for preparing graphene foam metal loaded with titanium dioxide-precious metal film

Technical field

The invention relates to the field of photocatalysis technology, in particular to a method for preparing a graphene foam metal loaded with a titanium dioxide-precious metal film.

Background technique

Titanium dioxide has the advantages of high photocatalytic activity, low cost and easy availability, good stability, non-toxicity and harmlessness, and is widely used in photocatalytic degradation of organic pollutants in air or sewage, sterilization, self-cleaning and the like. However, the titanium dioxide powder is easy to aggregate in the suspension system and is difficult to separate and recycle, which hinders its application. The use of catalyst immobilization is one of the effective ways to solve this problem, and is generally achieved by a method of preparing a photocatalytic film or coating.

At present, the colloidal solution of TiO ₂ is generally prepared by a sol-gel technique, and then the thickness of the film is quantitatively controlled by controlling the pulling speed and the number of times by using the immersion pulling method. The method can form a film on both sides of the substrate, and is suitable for A variety of temperature-resistant substrate materials such as glass, ceramics, stainless steel, etc. The TiO ₂ colloidal solution may also be applied to the surface of the substrate material by brushing, dispensing, spin coating or the like. However, this method is more suitable for the surface material with a flat surface to obtain a TiO ₂ film of a relatively uniform thickness. The TiO ₂ film can also be prepared by physical vapor deposition and chemical vapor deposition. The coating equipment is complex, has certain requirements on the degree of vacuum, and requires strict control of deposition conditions, high cost and complicated process.

Summary of the invention

The object of the present invention is to overcome the defects of the prior art and provide a method for preparing a graphene foam metal loaded with a titanium dioxide-precious metal film, which has a simple process and is easy to perform large-area plating; the operation is easier and safer.

In order to achieve the above object, the present invention adopts the following technical scheme, a method for preparing a graphene foam metal loaded with a titanium dioxide-precious metal film, comprising the steps of: preparing an electrolyte containing butyl titanate; and cleaning the surface on which the electroplated surface is deposited with graphene. Foam metal; put graphene foam metal into the electrolyte Electrochemical deposition, which is deposited by an electrochemical workstation comprising a working electrode, a counter electrode and a reference electrode, an electrolytic cell, the working electrode being a metal foam to be plated, The electrode is a platinum electrode, the reference electrode is a saturated calomel electrode, and the electrolyte is placed in an electrolytic cell; the electrochemically deposited graphitized foam metal loaded with a titanium dioxide-precious metal film is cleaned and dried; after cleaning and drying The graphene foam metal loaded with a titanium dioxide-precious metal film is sintered.

Preferably, the electrolyte containing the butyl titanate is specifically prepared as follows: 20-120 ml of deionized water is placed in the No. 1 cup, and 15-100 ml of absolute ethanol is placed in the No. 2 cup; and 100-500 ul is taken. Concentrated nitric acid was dropped into the No. 1 cup, then covered with plastic wrap, ultrasonicated with an ultrasonic cleaner for 5-30 min; 100-500 ul of hydrogen peroxide was dropped into the No. 2 cup, and then 0.1-1 g of titanate was added dropwise. The ester was covered with plastic wrap. The No. 1 cup and the No. 2 cup were placed in an ultrasonic cleaner for 5-30 min. After the end of the ultrasound, the solution of the No. 2 cup was poured into the No. 1 cup, and the plastic wrap was placed. Ultrasonic cleaning machine for ultrasonic 5-30min; into the No. 1 cup drops 100-500ul of chloroauric acid, and then covered with plastic wrap, placed in an ultrasonic cleaner for 5-30min.

Preferably, the foam metal on which the surface to be electroplated is deposited with graphene is specifically: a metal foam having graphene deposited on the surface, and after being placed in an acetone solution, ultrasonicating for 5-30 min; taking out the foam metal and adding absolute ethanol Then perform ultrasonic for 5-30 min; remove the foam metal and place it in deionized water for 5-30 min.

Preferably, the graphene foam metal is placed in the electrolyte for electrochemical deposition, specifically: the cleaned graphene foam metal is placed in the electrolyte, and the cyclic deposition is performed by electrochemical deposition.

Preferably, the graphene foam metal cleaning and drying of the electrochemically deposited titanium dioxide-precious metal film is specifically: after the electrochemical deposition is completed, the graphene foam metal supporting the titanium dioxide-precious metal film is taken out and deionized. Rinse the surface with water and then dry in an oven at 50-100 °C.

Preferably, the foamed metal after washing and drying is sintered to prepare a graphene foam metal supporting a titanium dioxide-precious metal film, specifically: heating the metal foam at a temperature of 300-600 ° C for 1-5 hours, and then heating The tempering was carried out for 1-5 hours, and after completion, the graphene foam metal supporting the titanium dioxide-precious metal film was taken out by cooling.

Preferably, the metal foam is nickel foam, copper foam or aluminum foam.

The invention adopts the above technical solution to deposit a titanium dioxide-precious metal film on a foam metal on which graphene is deposited, which can be produced at normal temperature without residual thermal stress problem, and is beneficial to enhancing the bonding force between the substrate and the coating. The process is simple, easy to carry out large-area plating; no need for high vacuum, no dangerous gas, etc.; operation is easier and safer; the surface of the foam metal can be uniformly deposited on the film, and the adhesion is good; the prepared titanium dioxide - The noble metal film is evenly distributed on the surface of the graphene in the metal foam, which not only improves the contact area, but also avoids the agglomeration of the self particles, effectively prolongs the carrier lifetime generated by the titanium dioxide-precious metal film, and prevents the recombination of holes and electrons. The prepared titanium dioxide-precious metal film was used for the photocatalytic degradation test of Rhodamine B solution, and the results showed that the material has high photocatalytic activity.

DRAWINGS

1 is a schematic flow chart of the method of the present invention;

2 is a schematic view showing the degradation rate of the rhodamine B solution of the graphene foam metal loaded with titanium dioxide-precious metal film prepared in Example 1-3 of the present invention.

detailed description

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Supported titania of the present invention - preparation of the noble metal thin film graphene metal foam, wherein the noble metal-modified TiO ₂ TiO ₂ is influenced by the surface properties of the electron distribution changes in the system, thereby improving the photocatalytic activity. The work function of the noble metal is higher than the work function of TiO ₂ . When the two materials are joined together, the electrons will continuously migrate from TiO ₂ to the deposited metal until the Fermi level of the two is equal. In the space charge layer formed after the contact between the two, the metal surface will obtain an excessive negative charge, and the negative charge on the surface of the TiO ₂ completely disappears, thereby greatly increasing the rate at which the photogenerated electrons are transported to the surface dissolved oxygen. The energy band of the semiconductor will bend upward toward the surface to form a lossy layer, forming a shallow well energy barrier that traps electrons at the noble metal-TiO ₂ interface, further suppressing the recombination of photogenerated electrons and holes. The deposition of noble metal on the surface of TiO ₂ is generally carried out by an immersion reduction method in which TiO _{2 is} immersed in a solution containing a noble metal salt and then reduced at a high temperature. Due to the high porosity, good mechanical properties, structural uniformity and hydrodynamic properties of the metal foam material, the foam metal-supported photocatalyst has a higher contact surface, and the photocatalyst has a wider effective range, which can effectively improve the photocatalytic efficiency. A good substrate material for supporting photocatalysts.

The electrochemical deposition according to the present invention is a process in electrophoretic painting, in which a charged resin particle reaches a counter electrode under the action of a direct current electric field, and is deposited by discharging (or obtaining electrons) a water-insoluble paint film. The surface of the coating. The reaction is first carried out at a site where the power line density is particularly high (such as the edge edges and tips of the object to be coated). Once the deposition occurs, the object to be coated has a certain degree of insulation, and the electrodeposition gradually moves to a portion where the power line density is low. Until finally a completely uniform coating is obtained.

The preparation method of the graphene foam metal loaded with the titanium dioxide-precious metal film according to the present invention is as follows:

S101: preparing an electrolyte containing butyl titanate;

S102: cleaning a metal foam on which a surface to be electroplated is deposited with graphene;

S103: placing graphene foam metal in an electrolyte for electrochemical deposition;

S104: cleaning and drying the graphene foam metal of the electrochemically deposited titanium dioxide-precious metal film;

S105: Sintering the graphene foam metal loaded with the titanium dioxide-precious metal film after washing and drying.

The specific implementation is as follows:

Example 1:

In this embodiment, the metal foam is nickel foam, and the specific steps are as follows:

Prepare 2 clean beakers, No. 1 and No. 2, and place No. 1 beaker into 50ml of deionized water, then take 100ul of concentrated nitric acid into the deionized water, cover the plastic wrap for 10min, and mix it thoroughly; Put the No. 2 beaker into 50ml of absolute ethanol, take 100ul of hydrogen peroxide and drip it into absolute ethanol, then Put the No. 2 beaker on the balance and add 0.1g of butyl titanate to cover the plastic wrap. After the ultrasonic solution of the No. 1 solution, put the No. 2 beaker into the ultrasonic cleaning machine and sonicate it for 10 minutes. After the end of the ultrasound, open it. The cling film is dripped into the No. 1 solution, and then covered with plastic wrap for 20 min, so that all the solutions are thoroughly mixed; 100 ul of chloroauric acid is dripped into the wrap film, and the wrap is covered with ultrasonic film for 10 min to obtain a titanate containing Ester electrolyte

The foamed nickel to be plated is placed in an acetone solution for 5 min, then ultrasonicated with absolute ethanol for 5 min, and finally ultrasonicated for 5 min with deionized water to wash the foamed nickel on which the graphene is deposited on the surface to be electroplated;

The cleaned foamed nickel is connected to the working electrode of the electrochemical workstation, and the platinum counter electrode and the saturated calomel reference electrode are connected, and the electrodes are placed together in the prepared electrolyte; the scanning speed is 50 mV/s, and the voltage range is -0.1-0.5V, the scanning cycle is 500 times for cyclic electrochemical deposition, wherein the object to be coated in the electrochemical deposition in this embodiment is foamed nickel with graphene, and the coating is titanium dioxide-precious metal. In the example, it is titanium dioxide-gold.

After the electrochemical deposition, the graphene foamed nickel coated with the titanium dioxide-precious metal film is taken out, the surface is rinsed with deionized water, and then dried in an oven at 100 ° C; then the nickel foam is placed in a muffle furnace and heated at 500 ° C. After 3 hours, the temperature was kept for 5 hours, and after completion, the graphene foamed nickel supporting the titanium dioxide-precious metal film was taken out by cooling.

The photocatalytic test and photoelectrocatalytic test of the titanium dioxide-precious metal film prepared by the invention are carried out:

Pour 100ml of 10mg/L Rhodamine B solution into the culture dish and submerge the foamed nickel; place the culture dish in the photochemical reactor for photocatalytic reaction; sample every 5 minutes, and measure the absorbance of the solution by UV-visible spectrophotometry. The photodegradation rate of Rhodamine B solution was calculated.

The graphene foamed nickel loaded with the titanium dioxide-precious metal film prepared above was first ultrasonicated with acetone for 5 min, then ultrasonicated with absolute ethanol for 5 min, and finally ultrasonicated with deionized water for 5 min; 100 ml of a NaOH solution having a concentration of 0.1 mol/L was placed. Into the beaker, as the test electrolyte; connect the foamed nickel to the working electrode of the electrochemical workstation, and connect the platinum counter electrode and the saturated calomel reference electrode, set the voltage to 0.5V; then start the test, after testing 600S, turn on the xenon light source, Irradiation on the working electrode, according to the cycle 100S, Break the light source and observe the change of current before and after the light source. The test results are shown in Figure 2.

The photocatalytic degradation of rhodamine B solution by the graphene foam nickel supported on the titanium dioxide-precious metal film obtained in the first embodiment has a degradation rate of 100% in 35 minutes, and the photocatalytic result is that the current of the xenon lamp source is increased from 11 mA to 14 mA, and the photocatalytic effect is obvious. .

Example 2:

Different from the first embodiment, the foam metal in the embodiment is foamed copper. In this embodiment, 50 ml of deionized water is placed in the beaker No. 1, 200 ul of concentrated nitric acid is added, and the plastic wrap is covered with ultrasonic for 10 min; Put the beaker into 50ml of absolute ethanol, add 200ul of hydrogen peroxide, place the beaker on the balance and add 0.2g of butyl titanate, cover the plastic wrap; and sonicate with the No. 1 solution for 10min, then open the wrap film after the end The No. 2 solution was dropped into the No. 1 solution, and the mixture was again covered with a plastic wrap for 20 min to allow the solution to be thoroughly mixed; the plastic wrap was again poured into 200 ul of chloroauric acid, and the cling film was ultrasonicated for 20 min to obtain the electrolytic solution of Example 2.

The foamed copper to be plated was placed in acetone solution for 20 min, then ultrasonicated with absolute ethanol for 20 min, and finally ultrasonicated with deionized water for 20 min; the cleaned foamed copper was connected to the working electrode of the electrochemical workstation, and platinum was connected. The counter electrode and the saturated calomel reference electrode are placed in the prepared electrolyte together; the electrochemical deposition is performed at a scanning speed of 50 mV/s, a voltage range of -0.1-0.5 V, and a scanning period of 200 times, wherein In the electrochemical deposition in this embodiment, the object to be coated is foamed copper with graphene, and the coating layer is titanium dioxide-precious metal.

After the electrochemical deposition, the copper oxide coated with the titanium dioxide-precious metal film was taken out, the surface was rinsed with deionized water, and then dried in an oven at 100 ° C; then the copper foam was placed in a muffle furnace and heated at 500 ° C for 3 hours. After 5 hours of heat retention, after completion, the graphene foam copper loaded with the titanium dioxide-precious metal film was taken out by cooling.

The photocatalytic test and the photoelectrocatalytic test procedure were the same as those in Example 1, and the test results are shown in FIG. The photocatalytic degradation of rhodamine B solution of graphene foam copper loaded with titanium dioxide-precious metal film obtained in the second embodiment has a degradation rate of 100% in 35 minutes, and the photocatalytic result is that the current of the xenon lamp source is increased from 11 mA to 14 mA, and the photocatalytic effect is obvious. .

Example 3:

Different from the first embodiment, the foam metal in the embodiment is aluminum foam. In this embodiment, 100 ml of deionized water is placed in a beaker No. 1, 500 ul of concentrated nitric acid is added, and the plastic wrap is covered with ultrasonic for 20 min; The beaker was placed in 100 ml of absolute ethanol, 500 ul of hydrogen peroxide was added dropwise, and the beaker was placed on the balance with 0.5 g of butyl titanate, and the plastic wrap was covered; the same solution was used for 20 min, and the plastic wrap was opened after the end. The No. 2 solution was dropped into the No. 1 solution, and the solution was again ultrasonicated for 20 minutes to allow the solution to be thoroughly mixed; the plastic wrap was again poured into 500 ul of silver nitrate, and the wrap film was ultrasonicated for 30 min to obtain the electrolytic solution of Example 3.

The foamed aluminum to be plated was ultrasonicated in acetone solution for 20 min, then ultrasonicated with absolute ethanol for 20 min, and finally ultrasonicated with deionized water for 20 min; the cleaned aluminum foam was connected to the working electrode of the electrochemical workstation, and platinum was connected at the same time. The counter electrode and the saturated calomel reference electrode are placed together in the prepared electrolyte; the electrochemical deposition is performed at a scanning speed of 50 mV/s, a voltage range of -0.1 to 0.5 V, and a scanning period of 500 times, wherein In the electrochemical deposition in this embodiment, the object to be coated is aluminum oxide with graphene, and the coating layer is titanium dioxide-precious metal, which is titanium dioxide-silver in this embodiment.

After the electrochemical deposition, the graphene aluminum foam coated with the titanium dioxide-precious metal film is taken out, the surface is rinsed with deionized water, and then dried in an oven at 100 ° C; then the aluminum foam is placed in a muffle furnace and heated at 500 ° C. After 3 hours, the temperature was kept for 5 hours. After the end, the graphene foam aluminum loaded with the titanium dioxide-precious metal film was taken out by cooling.

The photocatalytic test and the photoelectrocatalytic test procedure were the same as in Example 1.

The graphene foam aluminum loaded with the titanium dioxide-precious metal film obtained in the third embodiment was photocatalyzed to degrade the rhodamine B solution, and the test results are shown in FIG. 2 . The degradation rate reached 100% in 30min. The photocatalytic result was that the xenon lamp source was irradiated with 100S current from 11mA to 16mA, and the photocatalytic effect was obvious.

The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. Within the scope.

Claims

A method for preparing a graphene foam metal loaded with a titanium dioxide-precious metal film, characterized in that the method comprises the following steps:

Formulating an electrolyte containing butyl titanate;

Cleaning the foam metal on which the surface to be electroplated is deposited with graphene;

The graphene foam metal is placed in an electrolyte for electrochemical deposition, the electrochemical deposition is performed by using an electrochemical workstation comprising a working electrode, a counter electrode and a reference electrode, and an electrolytic cell, The working electrode is a metal foam to be plated, the counter electrode is a platinum electrode, the reference electrode is a saturated calomel electrode, and the electrolyte is placed in an electrolytic cell;

Cleaning and drying the graphitic foam metal of the electrochemically deposited titanium dioxide-precious metal film;

The graphene foam metal of the titanium dioxide-precious metal film after washing and drying is sintered.
The preparation method according to claim 1, wherein the preparation of the electrolyte containing butyl titanate is as follows:

Put 20-120ml of deionized water in the No. 1 cup and 15-100ml of absolute ethanol in the No. 2 cup;

Take 100-500ul of concentrated nitric acid into the No. 1 cup, then cover the plastic wrap and ultrasonically use ultrasonic cleaning machine for 5-30min;

Take 100-500 ul of hydrogen peroxide into the No. 2 cup, then add 0.1-1 g of butyl titanate, cover with plastic wrap, and place the No. 1 cup and the No. 2 cup in an ultrasonic cleaner for ultrasonic 5 - 30min;

After the end of the ultrasound, the solution of the No. 2 cup is poured into the No. 1 cup, covered with plastic wrap and placed in an ultrasonic cleaner for 5-30 min;

100-500 ul of chloroauric acid was added to the No. 1 cup, and the plastic wrap was again placed, and ultrasonically placed in an ultrasonic cleaner for 5-30 min.
The preparation method according to claim 1, wherein the foam metal on which the surface to be electroplated is deposited with graphene is specifically:

The foam metal on which the graphene is deposited is placed in an acetone solution and ultrasonicated for 5-30 min;

Remove the metal foam, put in anhydrous ethanol and perform ultrasonication for 5-30 min;

The foam metal was removed and placed in deionized water for ultrasound for 5-30 min.
The preparation method according to claim 1, wherein the depositing the graphene foam metal into the electrolyte for electrochemical deposition is specifically:

The cleaned graphene foam metal is placed in an electrolyte and subjected to cyclic deposition by electrochemical deposition.
The preparation method according to claim 1, characterized in that the graphene foam metal cleaning and drying of the electrochemically deposited titanium dioxide-precious metal film is specifically:

After the electrochemical deposition, the graphene foam metal loaded with the titanium dioxide-precious metal film was taken out, the surface was rinsed with deionized water, and then dried in an oven at 50-100 °C.
The preparation method according to claim 1, wherein the washing and drying of the foam metal is performed to prepare a graphene foam metal supporting the titanium dioxide-precious metal film, specifically:

The metal foam is heated at 300-600 ° C for 1-5 hours, and then held for 1-5 hours. After completion, the graphene foam metal supporting the titanium dioxide-precious metal film is taken out by cooling.
The preparation method according to claim 1, wherein the metal foam is nickel foam, copper foam or aluminum foam.