CN110241433B - Size-controllable AgCuO2 nanomaterials and their preparation and application - Google Patents

Abstract

The invention relates to a size-controllable _AgCuO2 nanomaterial and its preparation and application. The specific preparation process of the nanomaterial is as follows: (1) adding silver nitrate or silver acetate as a silver source and a divalent copper source to pure water in turn to dissolve, and then adding in NH ₃ H ₂ O is added under stirring to form a mixed solution, and an alkali source is added to make the solution strongly alkaline, and finally a stable and transparent dark blue solution (2) is obtained. The reaction is carried out at a certain temperature, and a current is passed on the working electrode for a certain period of time. After the deposition is completed, it is repeatedly rinsed with deionized water and ethanol, and dried, and finally AgCuO ₂ nanomaterials are obtained. Compared with the prior art, the raw material cost of the present invention is lower, the operation is simple, the reaction time is short, the temperature is low, the size of the obtained AgCuO ₂ nanoparticles is smaller, and the transparent film can be directly prepared, and has excellent physical and chemical properties, etc. .

Description

Size-controllable AgCuO2 nanomaterials and their preparation and application

technical field

The invention belongs to the technical field of p-type semiconductor nanomaterials, and relates to a size-controllable _AgCuO2 nanosheet and its preparation.

Background technique

AgCuO ₂ is composed of abundant and non-toxic elements of copper, silver and oxygen in the earth. It is an environmentally friendly manganite-like Ag-Cu multi-metal oxide p-type narrow-bandgap semiconductor material with a forbidden band width of 1.5-2.2eV, with good carrier mobility, optical transparency, and good thermal stability, and are widely used in p-type transparent semiconductors, battery cathode materials, photocatalysis, diodes, and solar cells. However, the current problems are: (1) To obtain pure-phase AgCuO ₂ material, Ag ₂ Cu ₂ O ₃ intermediate is required, so the energy consumption is high and the grain dispersion is poor; (2) The synthesized grain size is too large (micron level), the specific surface area is small, and it is not easy to form a film, which cannot fully highlight the advantages of nanomaterials, which limits the application range of materials. Therefore, it is of great significance to prepare _AgCuO nanoparticles with smaller grain size by a low-temperature method.

^AgCuO ₂ crystal belongs to monoclinic system, C2/m space group. Due to the difference in electronic structure, ^AgCuO _{2 crystal} has a layered structure. The ions replace the positions of Cu ⁺ and Mn ³⁺ , respectively, but the electronic valence structure of AgCuO ₂ is not exactly the same as that of manganese Cu ⁺ Mn ³⁺ O ₂ . In AgCuO ₂ , Ag and Cu do not have a single +1 and +3 valences, and there is charge delocalization between the three atoms of Ag, Cu, and O in the oxide, and both Ag and Cu are partially oxidized to high valence states. Therefore, the Oxides can be represented as Ag ^(1+x)+ Cu ^(2+y)+ _O2 , where the values of x and y vary with the preparation method.

The conventional method for preparing AgCuO ₂ crystals is to use the precursor Ag ₂ Cu ₂ O ₃ , on the basis of preparing Ag ₂ Cu ₂ O ₃ , use persulfate, perozone, etc. as oxidants to treat the Ag ₂ Cu ₂ O ₃ suspension. AgCuO ₂ is obtained by chemical oxidation, but the crystallinity of AgCuO ₂ obtained by chemical precipitation is not high. AgCuO ₂ solids have also been prepared by electrochemical oxidation of Ag ₂ Cu ₂ O ₃ . In 2001, J.Curda et al. used K ₂ S ₂ O ₈ as oxidant, Ag ₂ Cu ₂ O ₃ suspension and alkaline aqueous solution of AgNO ₃ and Cu(NO ₃ ) ₂ as precursors respectively, and obtained AgCuO ₂ by chemical oxidation. solid powder. (J. Curda, W. Klein, and M. Jansen, J. Solid State Chem., 162, 220 (2001).)

In recent years, studies have found that the reaction temperature and particle size of _AgCuO2 nanomaterials can be greatly reduced by using chemical deposition process. In 2014, Padmavathy N et al. used silver acetate and copper acetate as raw materials to prepare AgCuO ₂ nanoparticles with a size of nearly 100 nm at room temperature with persulfate (K ₂ S ₂ O ₈ ) as an oxidant under alkaline conditions. Films cannot be prepared. (RSC Advances, 2014, 4(107): 62746-62750.) At the same time, AgCuO ₂ solids were also prepared by electrochemical oxidation. In 2017, Lu et al. successfully fabricated nanosheets with a size close to 500 nm on the ITO working electrode by electrochemical deposition, but the film transmittance was not high due to the excessively large size, which is not suitable for solar cells. (Journal of The Electrochemical Society, 2017, 164(4):D130-D134.)

It can be found that the preparation of small particle size and highly dispersed AgCuO ₂ nanoparticles at low temperature is still a technical problem, and it is even more difficult to control the size of AgCuO ₂ nanoparticles by controlling the precursor concentration and reaction time. If the mass production of ultra-fine AgCuO ₂ nanoparticles with controllable size can be realized, it will not only obtain high economic benefits, but also be of great benefit to the promotion of AgCuO ₂ -based catalyst materials, solar cells and other fields.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a size-controllable AgCuO ₂ nanomaterial and its preparation and application in order to overcome the above-mentioned defects of the prior art, and innovatively adopts low-cost (CH ₃ COOAg or AgNO ₃ ) silver acetate or Silver nitrate is used as the silver source, and any divalent copper such as Cu(NO ₃ ) ₂ or Cu(CH ₃ COO) ₂ is used as the Cu source, and ultrafine AgCuO ₂ nanoparticles with controllable size can be obtained by electrodeposition reaction at low temperature in a water bath. The minimum particle size is close to 80 nm.

The object of the present invention can be realized through the following technical solutions:

One of the technical solutions of the present invention is to provide a method for preparing a size-controllable _AgCuO nanomaterial, which is characterized in that it includes the following steps:

(1) after the silver source and the divalent copper source solution are mixed uniformly, ammonia water is added to stir, and then the alkali source is added to make it strongly alkaline (pH≥13) to obtain a stable and transparent mixed solution for subsequent use;

(2) Using the mixed solution obtained in step (1) as an electrolyte solution, using the electrodeposition method, through the method of anodizing, electrifying the working electrode, and depositing AgCuO ₂ nanosheets, that is, it is completed.

Further, the silver source is silver nitrate or silver acetate, and the divalent copper source is copper nitrate or copper acetate.

Further, the molar ratio of the silver source to the divalent copper source is 1.1-1.5:1.

Further, the alkali source is sodium hydroxide and/or potassium hydroxide, and the addition amount thereof satisfies that the concentration of hydroxide ions in the mixed solution is 1-10 mol/L.

Further, the addition amount of ammonia water satisfies: its concentration in the mixed solution is 1-10 mol/L.

Further, the energization current of the working electrode is 0.01-0.4A, and the energization time is 30-300s.

Further, the temperature of the electrochemical deposition is 40-70°C.

The second technical solution of the present invention is to provide a size-controllable AgCuO ₂ nanomaterial, which is prepared by the above-mentioned preparation method. The prepared AgCuO ₂ nanomaterial is a two-dimensional nanosheet, and its lateral dimension is at least 80nm, and its thickness is 80nm. 15-30nm.

The third technical solution of the present invention is to provide the application of a size-controllable AgCuO ₂ nanomaterial as a p-type hole transport material in the preparation of solar cells.

The AgCuO ₂ nanosheet prepared in the present invention has a controllable size, and the minimum size reaches 80 nanometers, which is an excellent p-type hole transport material and can be used for perovskite solar cells and organic solar cells. The invention uses silver acetate as the silver source in the electrochemical deposition method for the first time, and prepares ultra-fine AgCuO ₂ nanosheets at low temperature. Before electrodeposition, it is necessary to add excess ammonia water and add strong alkali to adjust the acidity and alkalinity, and the purpose is to form a stable complex. If the amount of ammonia water and alkali source added is not within the conditions, the electrodeposition precursor solution cannot form a stable complex transparent solution. It is unfavorable for the synthesis of substances, and it is not conducive to the synthesis of products with uniform size. During the electrodeposition process, if the current size is not within the limited range, too low energization current will lead to impure phase of the synthesized product, and too high energization current will lead to excessively large and non-uniform product particle size. During the electrodeposition process, if the temperature setting is not within the limited range, the temperature will be too low, and the crystal nucleus will not be formed in the solution. If the temperature is too high, a large number of crystal nuclei will be formed rapidly inside the solution, and the size of the formed crystal nuclei will be too large, which will affect the product size and make the product size non-uniform.

The main principle of electrodeposition of AgCuO ₂ is that Ag(I) and Cu(II) in solution before electrodeposition mainly exist in the form of [Ag(NH ₃ ) ₂ ] ⁺ and [Cu(NH ₃ ) ₄ ] ²⁺ , and with During electrodeposition, the pH of the electrode surface drops, Ag ⁺ and Cu ²⁺ are gradually released, and react with OH ^- in the solution to form co-oxide AgCuO ₂ . In addition, the raw material of the present invention is cheap, the reaction operation is simple and convenient, and is more suitable for commercial promotion.

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

(1) Size controllable: the present invention can flexibly regulate the grain size of the nanosheets by adjusting the precursor concentration, temperature, energization time and current of the reaction system, thereby obtaining size-controllable nanosheets;

(2) Can be prepared into film: the silver source and copper source used in the present invention are cheap, and can be directly prepared into a film on the working electrode, and the transmittance is high, which solves the defect of large particle size and poor dispersion and difficult to form a film.

(3) The preparation process is simple: the present invention adopts a simple and efficient electrodeposition synthesis method to synthesize AgCuO ₂ nanosheets. Preparation of _AgCuO nanosheets;

(4) Excellent product performance: AgCuO ₂ nanosheets synthesized by the present invention have good crystallinity and excellent photoelectric properties, and the photoelectric conversion efficiency can exceed 4% after being used in perovskite solar cells.

Description of drawings

Fig. 1 is the field emission scanning electron microscope image of the _AgCuO nanosheet prepared in Example 1;

Fig. 2 is the field emission scanning electron microscope image of the AgCuO nanosheet prepared in Example ₂ ;

3 is a field emission scanning electron microscope image of the _AgCuO nanosheet prepared in Example 3;

4 is a field emission scanning electron microscope image of the _AgCuO nanosheet prepared in Example 4;

Fig. 5 is the X-ray diffraction pattern of the reaction product prepared by Ag:Cu molar ratio 1.25:1 in Example 1;

6 is a field emission scanning electron microscope image of the _AgCuO nanomaterial prepared in Comparative Example 1;

7 is a field emission scanning electron microscope image of the AgCuO nanomaterial prepared in Comparative Example ₂ ;

Figure 8 is the photocurrent-voltage curve of the AgCuO ₂ nanosheets prepared in Example 3 used in perovskite solar cells.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and provides a detailed implementation manner and a specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

In the following examples, the adopted raw materials or processing steps, unless otherwise specified, represent the existing conventional commercially available products or conventional techniques employed.

Example 1

At room temperature, according to the Ag:Cu molar ratio of 1.25:1, weigh CH ₃ COOAg and Cu(NO ₃ ) ₂ ·3H ₂ O, take 50 ml of pure water, and add 0.001875mol of silver acetate and 0.0015mol of silver acetate in turn under the condition of magnetic stirring Copper nitrate trihydrate, then 0.05mol ammonia water and 0.5mol sodium hydroxide were added to form a stable and transparent dark blue solution; the obtained reaction solution was electrodeposited, a current of 0.04A was passed on the working electrode, and the reaction temperature was controlled at 40°C , the electrification time is 100s; after the reaction, the precipitate is taken out, washed with pure water and ethanol, and dried repeatedly. FIG. 1 is a field emission scanning electron microscope image of the AgCuO ₂ nanosheets prepared in Example 1. It can be seen from the figure that the average diameter of the AgCuO ₂ nanosheets is about 80-100 nanometers.

Example 2

At room temperature, according to the Ag:Cu molar ratio of 1.25:1, weigh CH ₃ COOAg and Cu(NO ₃ ) ₂ ·3H ₂ O, take 50 ml of pure water, and add 0.001875mol of silver acetate and 0.0015mol of silver acetate in turn under the condition of magnetic stirring Copper nitrate trihydrate, then 0.05mol ammonia water and 0.1mol sodium hydroxide were added to form a stable and transparent dark blue solution; the obtained reaction solution was electrodeposited, and a current of 0.04A was passed on the working electrode, and the reaction temperature was controlled at 40°C , the energization time is 150s; after the reaction, the precipitate is taken out, washed with pure water and ethanol, and dried repeatedly. FIG. 2 is a field emission scanning electron microscope image of the AgCuO ₂ nanosheets prepared in Example 2. It can be seen from the figure that the average diameter of the AgCuO ₂ nanosheets is about 200-300 nanometers.

Example 3

At room temperature, according to the Ag:Cu molar ratio of 1.25:1, weigh CH ₃ COOAg and Cu(NO ₃ ) ₂ ·3H ₂ O, take 50 ml of pure water, and add 0.001875mol of silver acetate and 0.0015mol of silver acetate in turn under the condition of magnetic stirring Copper nitrate trihydrate, then 0.05mol ammonia water and 0.1mol sodium hydroxide were added to form a stable and transparent dark blue solution; the obtained reaction solution was electrodeposited, and a current of 0.04A was passed on the working electrode, and the reaction temperature was controlled at 40°C , the electrification time is 200s; after the reaction, the precipitate is taken out, washed with pure water and ethanol, and dried repeatedly. 3 is a field emission scanning electron microscope image of the AgCuO ₂ nanosheets prepared in Example 3. It can be seen from the figure that the average diameter of the AgCuO ₂ nanosheets is about 200-500 nanometers.

Comparing the AgCuO ₂ nanoparticles prepared in Examples 1 to 3, it can be found that reducing the electrification time can effectively reduce the size of the AgCuO ₂ nanoparticles.

Figure 5 is the X-ray diffraction pattern of the product prepared in Example 3. It can be found that the products are all pure AgCuO ₂ phase without other impurities.

Further, AgCuO ₂ nanosheets were prepared by electrodeposition technology on the surface of conductive glass (FTO or ITO) to prepare AgCuO ₂ thin film materials, which were used as hole transport materials for perovskite solar cells. Figure 8 is the photocurrent-voltage curve of the prepared perovskite solar cell, and it can be found that the efficiency of the cell can reach 13%.

Example 4

At room temperature, according to the Ag:Cu molar ratio of 1.5:1, weigh CH ₃ COOAg and Cu(NO ₃ ) ₂ ·3H ₂ O, take 50 ml of pure water, and add 0.015mol silver acetate and 0.0136mol successively under the condition of magnetic stirring Copper nitrate trihydrate, 0.5mol ammonia water and 0.1mol sodium hydroxide were added to form a stable and transparent dark blue solution; the obtained reaction solution was electrodeposited, a current of 0.4A was passed on the working electrode, and the reaction temperature was controlled at 70°C , the electrification time is 30s; after the reaction is completed, the precipitate is taken out, washed with pure water and ethanol repeatedly, and dried to obtain ultra-fine AgCuO ₂ nanomaterials. FIG. 4 is a field emission scanning electron microscope image of the AgCuO ₂ nanosheets prepared in Example 4. It can be seen from the figure that the average diameter of the AgCuO ₂ nanosheets is about 500-2000 nanometers.

Comparative Example 1

At room temperature, according to the Ag:Cu molar ratio of 1.25:1, weigh CH ₃ COOAg and Cu(NO ₃ ) ₂ ·3H ₂ O, take 50 ml of pure water, and add 0.001875mol of silver acetate and 0.0015mol of silver acetate in turn under the condition of magnetic stirring Copper nitrate trihydrate, then 0.05mol ammonia water and 0.1mol sodium hydroxide were added to form a stable and transparent dark blue solution; the obtained reaction solution was electrodeposited, and a current of 0.04A was passed on the working electrode, and the reaction temperature was controlled at 30°C , the electrification time is 100s; after the reaction, the precipitate is taken out, washed with pure water and ethanol, and dried repeatedly. Figure 6 is a field emission scanning electron microscope image of the AgCuO ₂ nanomaterial prepared in Comparative Example 1. From the figure, it can be seen that the shape of the AgCuO ₂ material is irregular in shape and size, and the average diameter is about 100-300 nm.

Comparative Example 2

At room temperature, according to the Ag:Cu molar ratio of 1.25:1, weigh CH ₃ COOAg and Cu(NO ₃ ) ₂ ·3H ₂ O, take 50 ml of pure water, and add 0.001875mol of silver acetate and 0.0015mol of silver acetate in turn under the condition of magnetic stirring Copper nitrate trihydrate, then 0.05mol ammonia water and 0.1mol sodium hydroxide were added to form a stable and transparent dark blue solution; the obtained reaction solution, by electrodeposition method, passed a current of 0.04A on the working electrode, and the reaction temperature was controlled at 80°C , the electrification time is 100s; after the reaction, the precipitate is taken out, washed with pure water and ethanol, and dried repeatedly. Figure 7 is a field emission scanning electron microscope image of the AgCuO ₂ nanosheets prepared in Comparative Example 2. From the figure, it can be seen that the AgCuO ₂ nanomaterials are irregular in shape and size, with an average diameter of about 100-300 nanometers.

Example 5

AgNO ₃ and Cu(NO ₃ ) ₂ ·3H ₂ O were weighed according to the Ag:Cu molar ratio of 1.25:1 at room temperature, 50 ml of pure water was taken, and 0.001875 mol of silver nitrate and 0.0015 mol of trisodium chloride were added in sequence under the condition of magnetic stirring. water copper nitrate, and then add 0.05mol ammonia and 0.1mol sodium hydroxide to form a stable and transparent dark blue solution; the obtained reaction solution adopts the electrodeposition method to pass a current of 0.04A on the working electrode, and the reaction temperature is controlled at 40 ℃, The electrification time is 100s; after the reaction is completed, the precipitate is taken out, washed with pure water and ethanol repeatedly, and dried to obtain ultra-fine AgCuO ₂ nanomaterials.

Example 6

AgNO ₃ and Cu(CH ₃ COO) ₂ ·H ₂ O were weighed according to the Ag:Cu molar ratio of 1.25:1 at room temperature, 50 ml of pure water was taken, and 0.001875 mol of silver nitrate and 0.0015 mol of silver nitrate were added in sequence under the condition of magnetic stirring. Copper acetate monohydrate, then 0.05mol ammonia water and 0.1mol sodium hydroxide were added to form a stable and transparent dark blue solution; the obtained reaction solution, by electrodeposition method, passed a current of 0.04A on the working electrode, and the reaction temperature was controlled at 40°C , the electrification time is 100s; after the reaction is completed, the precipitate is taken out, washed with pure water and ethanol repeatedly, and dried to obtain ultra-fine AgCuO ₂ nanomaterials.

In the above embodiments, the copper source used can be replaced by any one of Cu(NO ₃ ) ₂ or Cu(CH ₃ COO) ₂ ·H ₂ O on the premise of maintaining the total molar amount added. or a mixture of the two. Likewise, the source of alkalinity can also be replaced by any one or a combination of both sodium hydroxide or potassium hydroxide.

Example 7

Compared with Example 1, most of them are the same, except that in this example, the molar ratio of the silver source to the divalent copper source is 1.5:1.

Example 8

Compared with Example 1, most of them are the same, except that in this example, the molar ratio of the silver source to the divalent copper source is 1.1:1.

Example 9

Compared with Embodiment 1, most of the parts are the same, except that in this embodiment, the energization current of the working electrode is 0.1A, and the energization time is 80s.

Example 10

Compared with Embodiment 1, most of the parts are the same, except that in this embodiment, the energization current of the working electrode is 0.01A, and the energization time is 300s.

Example 11

Compared with Example 1, most of them are the same, except that in this example: the temperature of electrochemical deposition is 50°C.

The foregoing description of the embodiments is provided to facilitate understanding and use of the invention by those of ordinary skill in the art. It will be apparent to those skilled in the art that various modifications to these embodiments can be readily made, and the generic principles described herein can be applied to other embodiments without inventive step. Therefore, the present invention is not limited to the above-mentioned embodiments, and improvements and modifications made by those skilled in the art according to the disclosure of the present invention without departing from the scope of the present invention should all fall within the protection scope of the present invention.

Claims (3)

1. the preparation method of a size-controllable _AgCuO nanomaterial, is characterized in that, comprises the following steps: (1) after the silver source and the bivalent copper source solution are mixed uniformly, add ammonia water to stir, then add the alkali source, and obtain a stable and transparent mixed solution for subsequent use; (2) using the mixed solution obtained in step (1) as an electrolyte solution, using an electrodeposition method, energizing the working electrode, and depositing AgCuO nanosheets to obtain _AgCuO nanosheets, that is, completion; The silver source is silver nitrate or silver acetate, and the divalent copper source is copper nitrate or copper acetate; The molar ratio of silver source and divalent copper source is 1.1-1.5:1; Described alkali source is sodium hydroxide and/or potassium hydroxide, and its addition amount satisfies that the concentration of hydroxide ion in the mixed solution is 1-10mol/L; The addition amount of ammonia water satisfies: its concentration in the mixed solution is 1-10mol/L; The energization current of the working electrode is 0.01-0.4A, and the energization time is 100-200s; The temperature of the electrochemical deposition was 40°C. 2. A size-controllable AgCuO ₂ nanometer material, which is prepared by the preparation method as claimed in claim 1, wherein the obtained AgCuO ₂ nanometer material is a two-dimensional nano-sheet, and its lateral dimension is at least 80nm , the thickness is 15-30nm. 3. The application of a size-controllable AgCuO ₂ nanomaterial as claimed in claim 2 as a p-type hole transport material in the preparation of solar cells.

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