CN113584552B - Preparation method and application of nano composite film - Google Patents

Abstract

The invention discloses a preparation method of a nano composite film, which comprises the following steps of putting a cleaned conductive substrate electrode into a prepared ammonium heptamolybdate solution for electrodeposition to obtain a molybdenum oxide film material. And carrying out electrodeposition on the prepared molybdenum oxide film material in a hydrochloric acid solution of palladium chloride by using the same method to obtain the palladium nanoparticle open-embedded molybdenum oxide film material. The method provided by the invention has the advantages of simple preparation process, extremely short preparation time, simple instrument and equipment, excellent performance of the nano composite film and obvious application value.

Description

A kind of preparation method and application of nanocomposite film

technical field

The invention relates to the technical field of composite nano-film materials, and more particularly to a preparation method and application of a nano-composite film.

Background technique

Nanocomposite thin film materials have better properties than single nanomaterials and are widely used in electronics, sensors, energy storage, lubricants, electrochromic, photochromic, catalysts and other fields. The preparation method of conventional nanocomposite thin film materials is to prepare two kinds of nanomaterials separately, then simply mix two or more kinds of nanomaterials, and prepare nanocomposite thin film materials by blade coating or spin coating. The preparation process of such nano-composite film material is complicated, time-consuming, and high cost. The components of the composite film material are prone to bury each other, and the active components cannot be fully exposed on the surface of the material, resulting in the loss of the active components.

At present, nano-composite film materials are generally prepared by first preparing each component of the composite film, and then preparing the nano-composite film by multi-component mixing by blade coating or spin coating. The rate is low, and the performance of each component cannot be fully utilized.

Therefore, how to provide a preparation method for developing a nanocomposite thin film material with simple preparation process, low cost, time saving and high efficiency is an urgent problem to be solved by those skilled in the art.

SUMMARY OF THE INVENTION

In view of this, the present invention provides a preparation method and application of a nanocomposite thin film. The present invention utilizes wet electrodeposition to prepare a molybdenum oxide thin film and open embedded metal nanoparticles. The preparation process is simple, the preparation time is extremely short, the equipment is simple, the nanocomposite film has excellent performance, and has significant application value.

In order to achieve the above object, the present invention adopts the following technical solutions:

A preparation method of nanocomposite film, comprising the following steps:

(1) Smooth the conductive substrate with 3000-grit sandpaper and wash it;

(2) configure the hydrochloric acid solution of ammonium heptamolybdate solution and palladium chloride;

(3) using a three-electrode system for electrodeposition, placing the ammonium heptamolybdate solution in an electrolytic cell, and then placing the three electrodes in the ammonium heptamolybdate solution for electrodeposition to obtain a molybdenum oxide film;

(4) placing the molybdenum oxide film in a hydrochloric acid solution of palladium chloride, and then using three electrodes for electrodeposition to obtain the nanocomposite film.

Preferably, the conductive substrate in step (1) is a disc gold/carbon conductive substrate with a diameter of 3 mm.

Preferably, the cleaning in step (1) is to put the polished conductive substrate into sulfuric acid, acetone, alcohol and secondary water in sequence for 4-6 minutes, and the ultrasonic frequency is 40kHZ.

Cleaning in the above steps refers to removing surface dust and other adsorbents and grease, etc., the purpose is to improve the degree of connection between the film and the conductive substrate, and prevent falling off.

Preferably, the concentration of the ammonium heptamolybdate solution in step (2) is 1-100 mM; in the hydrochloric acid solution of the palladium chloride, the concentration of the palladium chloride is 0.1-100 mM, and the palladium chloride and The molar concentration ratio of hydrochloric acid is (1:2)-(1:10).

In the above setting, the concentration of the ammonium heptamolybdate solution is the concentration that can obtain the thin film by electrodeposition, and the thin film can be obtained within the concentration range;

The concentration ratio is limited by the ratio that can effectively electrodeposit palladium, and too low or too high is unfavorable for the electrodeposition of palladium.

Preferably, the three electrodes include a working electrode, a reference electrode and a counter electrode, and the material of the working electrode is a conductive substrate; the material of the reference electrode is silver/silver chloride; the material of the counter electrode is a carbon rod.

Preferably, in step (3), the electrodeposition is performed by means of constant voltage or constant current, the deposition time is 0.001s-10s, the voltage is -0.5～-1.0V, and the current is 1- 500mA/cm ² .

In the above steps, the film thickness can be controlled by controlling the deposition amount or deposition time.

Preferably, in step (4), the electrodeposition is performed by means of constant voltage or constant current, the deposition time is 0.001s-10s, the voltage is 0-0.6V, and the current is 1-500mA /cm ² .

Another object of the present invention is to provide the application of the nanocomposite film prepared by the above-mentioned method for preparing a nanocomposite film in optical/electrochromic films, catalysts and sensing materials.

As can be seen from the above-mentioned technical solutions, compared with the prior art, the present invention has the following beneficial effects:

Due to the relatively large molecular size of ammonium heptamolybdate, the precursor of molybdenum oxide, a large number of molybdenum oxide products can be generated by transferring unit charge during electrodeposition, which can cover a large area of conductive substrate. In addition, molybdenum oxide is a semiconductor with high resistance, and the oxidation of continuous deposition Molybdenum tends to continue to deposit at lower resistance un-deposited or less-deposited sites, thus enabling efficient formation of nanoscale extremely thin films. When metal nanoparticles are further deposited, the crystal and oxygen defect sites of the molybdenum oxide film have higher surface energy and lower resistance, resulting in the preferential growth of electrodeposited metal atoms at the defect sites, and finally the formation of nanoparticles that are open and embedded in the molybdenum oxide film. Composite structure. The size of the nanoparticles involved in this structure is 1-100 nm, and the thickness of the molybdenum oxide film is 1 nm-10 μm. This special structure combines the properties of molybdenum oxide and metal nanoparticles at the same time, and the nanoparticles are in the pores to ensure long-term stability.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only It is an embodiment of the present invention. For those of ordinary skill in the art, other drawings can also be obtained according to the provided drawings without creative work.

Fig. 1 is the SEM image of molybdenum oxide thin film;

Fig. 2 is the SEM image of palladium-molybdenum oxide composite thin film material;

Figure 3 is a comparison of linear sweep voltammetry (LSV) images of palladium nanoparticles embedded in molybdenum oxide films in 1 mol/L KOH solution catalyzing the hydrogen evolution reaction;

Figure 4 is a comparison of the linear sweep voltammetry (LSV) images of the palladium nanoparticles embedded in the molybdenum oxide film before and after 500 cycles of circulation in a 1 mol/L KOH solution.

Detailed ways

The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Example 1

A preparation method of nanocomposite film, comprising the following steps:

(1) Polish the 3mm diameter disc gold conductive substrate to smooth, and put it into sulfuric acid, acetone, alcohol and secondary water for ultrasonic 4min in turn (ultrasonic treatment is required in sulfuric acid, acetone, alcohol and secondary water);

(2) the ammonium heptamolybdate solution with a configuration concentration of 100mM; in the HCl solution of 30mM, add the PdCl of 10mM to obtain the hydrochloric _acid solution of palladium chloride;

(3) Electrodeposition is carried out by using a three-electrode system, using the disc gold conductive substrate as the working electrode, silver/silver chloride as the reference electrode, and a carbon rod as the counter electrode, placing the ammonium heptamolybdate solution in the electrolytic cell, and then The three electrodes were placed in an ammonium heptamolybdate solution at -0.8V, and deposited for 1 s to obtain a molybdenum oxide film;

(4) placing the platinum oxide film in the hydrochloric acid solution of palladium chloride, then utilizing the three-electrode system at -0.3V to deposit 10s to obtain the nanocomposite film, and the obtained palladium nanoparticle size is about 25nm, The molybdenum oxide film generates high-density holes, and the palladium nanoparticles are openly embedded in the molybdenum oxide film.

Example 2

A preparation method of nanocomposite film, comprising the following steps:

(1) The 3mm diameter disc gold conductive substrate is polished smooth with sandpaper, and placed in sulfuric acid, acetone, alcohol and secondary water for ultrasonic 4min in turn (all need ultrasonic treatment in sulfuric acid, acetone, alcohol and secondary water);

( ₂ ) in the HCl solution of 10mM, add the PdCl of 2mM to obtain the hydrochloric acid solution of palladium chloride, and then configure the ammonium heptamolybdate solution with a concentration of 10mM;

(3) Electrodeposition is carried out by using a three-electrode system, using the disc gold conductive substrate as the working electrode, silver/silver chloride as the reference electrode, and a carbon rod as the counter electrode, placing the ammonium heptamolybdate solution in the electrolytic cell, and then The three electrodes were placed in an ammonium heptamolybdate solution at -0.7V, and deposited for 0.1s to obtain a molybdenum oxide film;

(4) placing the molybdenum oxide film in a hydrochloric acid solution of palladium chloride, and then using a three-electrode system at -0.4V to deposit for 5s to obtain the nanocomposite film.

Example 3

A preparation method of nanocomposite film, comprising the following steps:

(1) Grind the 3mm diameter disc carbon conductive substrate smooth, and put it into sulfuric acid, acetone, alcohol and secondary water for ultrasonic 4min in turn (ultrasonic treatment is required in sulfuric acid, acetone, alcohol and secondary water);

( ₂ ) adding 0.5mM PdCl to the 2mM HCl solution to obtain the hydrochloric acid solution of palladium chloride, and then configuring the ammonium heptamolybdate solution with a concentration of 100mM;

(3) Electrodeposition is carried out by using a three-electrode system, using the disc carbon conductive substrate as the working electrode, silver/silver chloride as the reference electrode, and a carbon rod as the counter electrode, placing the ammonium heptamolybdate solution in the electrolytic cell, and then The three electrodes were placed in an ammonium heptamolybdate solution at -0.9V, and deposited for 10ms to obtain a molybdenum oxide film;

(4) The molybdenum oxide film is placed in a hydrochloric acid solution of palladium chloride, and then three electrodes are used to deposit at -0.5V for 2s to obtain the nanocomposite film.

Example 4

A preparation method of nanocomposite film, comprising the following steps:

(1) Grind the 3mm diameter disc gold conductive substrate smooth, and put it into sulfuric acid, acetone, alcohol and secondary water for ultrasonic 4min in turn (all need ultrasonic treatment in sulfuric acid, acetone, alcohol and secondary water);

(2) the ammonium heptamolybdate solution with a configuration concentration of 100 mM is added; 0.2 mM of PdCl is added to the ₁ mM HCl solution to obtain a hydrochloric acid solution of palladium chloride;

(3) Electrodeposition is carried out by using a three-electrode system, using the disc gold conductive substrate as the working electrode, silver/silver chloride as the reference electrode, and a carbon rod as the counter electrode, placing the ammonium heptamolybdate solution in the electrolytic cell, and then The three electrodes were placed in an ammonium heptamolybdate solution at 10 mA/cm ² and deposited for 3 s to obtain a molybdenum oxide film;

(4) placing the molybdenum oxide film in a hydrochloric acid solution of palladium chloride, and then using a three-electrode system at 1 mA/cm ² to deposit for 1 s to obtain the nanocomposite film.

Example 5

A preparation method of nanocomposite film, comprising the following steps:

(1) Grind the 3mm diameter disc carbon conductive substrate smooth, and put it into sulfuric acid, acetone, alcohol and secondary water for ultrasonic 4min in turn (ultrasonic treatment is required in sulfuric acid, acetone, alcohol and secondary water);

(2) the ammonium heptamolybdate solution with a configuration concentration of 100 mM is added; ₁ mM of PdCl is added to the 10 mM HCl solution to obtain a hydrochloric acid solution of palladium chloride;

(3) Electrodeposition is carried out by using a three-electrode system, using the disc carbon conductive substrate as the working electrode, silver/silver chloride as the reference electrode, and a carbon rod as the counter electrode, placing the ammonium heptamolybdate solution in the electrolytic cell, and then The three electrodes were placed in an ammonium heptamolybdate solution at 1 mA/cm ² and deposited for 0.1 s to obtain a molybdenum oxide film;

(4) placing the molybdenum oxide thin film in a hydrochloric acid solution of palladium chloride, and then using three electrodes to deposit for 0.2 s at 20 mA/cm ² to obtain the nanocomposite thin film.

Example 6

The catalytic performance of the molybdenum oxide film and the palladium nanoparticle open-embedded composite molybdenum oxide film prepared in Example 1 were tested by electrochemical hydrogen evolution reaction, and the solution was 1 mol/L KOH.

The SEM image of the obtained electrodeposited molybdenum oxide film is shown in FIG. 1 . It can be seen from the figure that the molybdenum oxide is a two-dimensional film structure, and the surface is very smooth and flat. As shown in Table 1, its chemical composition is MoO _x (2≤x≤3).

Table 1 Molybdenum oxide X-ray energy spectrum composition analysis

The SEM image of the obtained palladium nanoparticle open-embedded molybdenum oxide thin film is shown in FIG. 2 . It can be seen from the figure that the material has high-density nanopores, and the pores are palladium nanoparticles.

The linear cyclic voltammetry curve of the obtained palladium nanoparticle open intercalation molybdenum oxide thin film material in 1mol/L KOH solution is shown in Figure 3. It can be seen from the figure that the onset potential is low (about -60mV), 10mA/L ^The overpotentials at current densities of cm and 100 mA/cm are 90 mV and ²⁰⁰ mV, respectively, indicating that the material has high catalytic hydrogen evolution performance, which is significantly higher than that of molybdenum oxide films and pure palladium nanoparticles.

The linear sweep voltammetry (LSV) diagrams of the obtained palladium nanoparticle open intercalation molybdenum oxide thin film material before and after 500 cycles of circulation in a 1 mol/L KOH solution are shown in Fig. 4 . It can be seen from the figure that the LSV diagram of the material before and after 500 CV sweeps in 1 mol/L KOH solution changes little, indicating that the material has high stability.

The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the various embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant part can be referred to the description of the method.

The above description of the disclosed embodiments enables any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (4)

1. a preparation method of nanocomposite film, is characterized in that, comprises the following steps: (1) Smooth the conductive substrate with 3000-grit sandpaper and wash it; Wherein, the conductive substrate is a disc gold/carbon conductive substrate with a diameter of 3 mm; (2) configure the hydrochloric acid solution of ammonium heptamolybdate solution and palladium chloride; (3) using a three-electrode system for electrodeposition, placing the ammonium heptamolybdate solution in an electrolytic cell, and then placing the three electrodes in the ammonium heptamolybdate solution for electrodeposition to obtain a molybdenum oxide film; (4) placing the molybdenum oxide film in a hydrochloric acid solution of palladium chloride, and then using a three-electrode system for electrodeposition to finally form a composite structure in which the nanoparticles are openly embedded in the molybdenum oxide film; The concentration of the ammonium heptamolybdate solution described in the step (2) is 0.1-100mM; in the hydrochloric acid solution of the palladium chloride, the concentration of the palladium chloride is 0.1-100mM, the moles of the palladium chloride and hydrochloric acid are The concentration ratio is (1:2)-(1:10); In the step (3), the electrodeposition is performed by using a constant voltage or constant current for 0.001s-10s, the voltage is -0.5～-1.0V, and the current is 1-500mA/cm ² ; In the step (4), the electrodeposition is performed by a constant voltage or constant current for 0.001s-10s, the voltage is 0-0.6V, and the current is 1-500mA/cm ² . 2. the preparation method of nano-composite film according to claim 1, is characterized in that, described in step (1) is to put the polished conductive substrate into sulfuric acid, acetone, alcohol and secondary water ultrasonic 4- 6min, the ultrasonic frequency is 40kHz. 3. The preparation method of nanocomposite film according to claim 1, is characterized in that, described three electrodes comprise working electrode, reference electrode and counter electrode; The material of described reference electrode is silver/silver chloride; The material of the electrode is carbon rod. 4. Application of the composite structure of the nanoparticle open and embedded molybdenum oxide film prepared by the preparation method of a nanocomposite film according to any one of claims 1-3 in optical/electrochromic films, catalysts, and sensing materials.

Images