A method for preparing superfine silver powder by using a surfactant-free microemulsion

Abstract

This invention belongs to the field of precious metal materials technology and discloses a method for preparing ultrafine silver powder using a surfactant-free microemulsion. The method includes the following steps: mixing n-octanol, ethanol, and silver nitrate solution to obtain microemulsion A; mixing n-octanol, ethanol, and ascorbic acid solution to obtain microemulsion B; mixing microemulsion A and microemulsion B, and allowing them to stand to obtain silver powder. The silver powder prepared by this invention is in the form of irregular particles with a particle size of 0.2–0.8 μm and a loose packing density of 1.6–1.9 g / cm³. 3 The tap density is 3.6–3.9 g / cm³. 3 .

Description

Technical Field

[0001] This invention relates to the field of precious metal materials technology, and in particular to a method for preparing ultrafine silver powder from a surfactant-free microemulsion. Background Technology

[0002] The photovoltaic industry is developing rapidly, and photovoltaic power generation, as a renewable energy technology, will be one of the main power generation methods in my country in the future. Ultrafine silver powder, as an important component of the front electrode of solar cells, is in increasing demand. Microemulsion is one of the main methods for preparing ultrafine silver powder. The formation of traditional microemulsions (SBMEs) requires the use of large amounts of surfactants and co-surfactants, necessitating multiple washes to remove them.

[0003] Therefore, it is of great significance to provide a mild and simple preparation process for ultrafine silver powder. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing ultrafine silver powder from surfactant-free microemulsions, thereby solving the problems existing in the prior art.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for preparing ultrafine silver powder using a surfactant-free microemulsion, comprising the following steps:

[0007] (1) Mix n-octanol, ethanol and silver nitrate solution to obtain microemulsion A;

[0008] (2) Mix n-octanol, ethanol, and ascorbic acid solution to obtain microemulsion B;

[0009] (3) Mix microemulsion A and microemulsion B, let stand, and obtain silver powder;

[0010] There is no order restriction between steps (1) and (2).

[0011] Preferably, in the above-mentioned method for preparing ultrafine silver powder from a surfactant-free microemulsion, the molar concentration of the silver nitrate solution in step (1) is 0.05 to 0.12 mol / L.

[0012] Preferably, in the above-mentioned method for preparing ultrafine silver powder from a surfactant-free microemulsion, the mass ratio of n-octanol, ethanol, and silver nitrate solution in step (1) is 3:4-6:1-3.

[0013] Preferably, in the above-mentioned method for preparing ultrafine silver powder from a surfactant-free microemulsion, the molar concentration of the ascorbic acid solution in step (2) is 0.05 to 0.25 mol / L.

[0014] Preferably, in the above-mentioned method for preparing ultrafine silver powder from a surfactant-free microemulsion, the mass ratio of n-octanol, ethanol, and ascorbic acid solution in step (2) is 3:4-6:1-3.

[0015] Preferably, in the above-mentioned method for preparing ultrafine silver powder from a surfactant-free microemulsion, the molar ratio of silver nitrate solution in step (1) to ascorbic acid solution in step (2) is 1:1 to 3.

[0016] Preferably, in the above-mentioned method for preparing ultrafine silver powder from a surfactant-free microemulsion, the mass ratio of microemulsion A to microemulsion B in step (3) is 1:1 to 3.

[0017] As can be seen from the above technical solution, compared with the prior art, the present invention has the following beneficial effects:

[0018] This invention uses surfactant-free microemulsions (SFMEs) as templates to prepare ultrafine silver powder. The process is simple, the conditions are mild, and it is easy to mass-produce. The silver powder prepared by this invention is in the form of irregular particles with a particle size of 0.2–0.8 μm and a bulk density of 1.6–1.9 g / cm³. 3 The tap density is 3.6–3.9 g / cm³. 3 . Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0020] Figure 1 To implement the SEM image of silver powder in Case 1;

[0021] Figure 2 To implement the X-ray diffraction pattern of silver powder in Case 1;

[0022] Figure 3 To implement the SEM image of silver powder in Case 2;

[0023] Figure 4 To implement the SEM image of silver powder in Case 3;

[0024] Figure 5 The SEM image of the silver powder in Case 4 is shown. Detailed Implementation

[0025] This invention provides a method for preparing ultrafine silver powder using a surfactant-free microemulsion, comprising the following steps:

[0026] (1) Mix n-octanol, ethanol and silver nitrate solution to obtain microemulsion A;

[0027] (2) Mix n-octanol, ethanol, and ascorbic acid solution to obtain microemulsion B;

[0028] (3) Mix microemulsion A and microemulsion B, let stand, and obtain silver powder;

[0029] There is no order restriction between steps (1) and (2).

[0030] In this invention, the molar concentration of the silver nitrate solution in step (1) is preferably 0.05 to 0.12 mol / L, more preferably 0.075 to 0.1 mol / L, and even more preferably 0.082 to 0.093 mol / L.

[0031] In this invention, the mass ratio of n-octanol, ethanol, and silver nitrate solution in step (1) is preferably 3:4-6:1-3, more preferably 3:4.2-5.7:1.4-2.5, and even more preferably 3:4.7-5.5:1.7-2.

[0032] In this invention, the specific mixing process in steps (1) and (2) is independently mixing and stirring at room temperature.

[0033] In this invention, the molar concentration of the ascorbic acid solution in step (2) is preferably 0.05 to 0.25 mol / L, more preferably 0.08 to 0.23 mol / L, and even more preferably 0.1 to 0.2 mol / L.

[0034] In this invention, the mass ratio of n-octanol, ethanol, and ascorbic acid solution in step (2) is preferably 3:4-6:1-3, more preferably 3:4.2-5.7:1.4-2.5, and even more preferably 3:4.7-5.5:1.7-2.

[0035] In this invention, the molar ratio of silver nitrate solution in step (1) to ascorbic acid solution in step (2) is preferably 1:1 to 3, more preferably 1:1.2 to 2.7, and even more preferably 1:1.9 to 2.3.

[0036] In this invention, the standing condition in step (3) is to stand at room temperature for 10 hours; after standing in step (3), the supernatant is removed, and the product is washed and dried.

[0037] In this invention, the mass ratio of microemulsion A to microemulsion B in step (3) is preferably 1:1 to 3, more preferably 1:1.5 to 2.7, and even more preferably 1:1.8 to 2.3.

[0038] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] Example 1

[0040] This invention provides a method for preparing ultrafine silver powder using a surfactant-free microemulsion, comprising the following steps:

[0041] (1) Mix n-octanol, ethanol and silver nitrate solution at room temperature and stir. The emulsion changes from turbid to transparent to obtain microemulsion A; wherein, the molar concentration of silver nitrate solution is 0.05 mol / L and the mass ratio of n-octanol, ethanol and silver nitrate solution is 3:4:3;

[0042] (2) Mix n-octanol, ethanol and ascorbic acid solution at room temperature and stir. The emulsion changes from turbid to transparent to obtain microemulsion B. The molar concentration of ascorbic acid solution is 0.05 mol / L and the mass ratio of n-octanol, ethanol and ascorbic acid solution is 3:4:3.

[0043] (3) Microemulsion B was added to microemulsion A and allowed to stand at room temperature for 10 hours to obtain a solid precipitate. The supernatant was removed, and the silver powder was obtained after washing and drying. The mass ratio of microemulsion A to microemulsion B was 1:1.

[0044] Testing revealed that the silver powder prepared above had a particle size of 0.2–0.8 μm and a loose packing density of 1.9 g / cm³. 3 The tap density is 3.9 g / cm³. 3 .

[0045] Example 2

[0046] This invention provides a method for preparing ultrafine silver powder using a surfactant-free microemulsion, comprising the following steps:

[0047] (1) Mix n-octanol, ethanol and silver nitrate solution at room temperature and stir. The emulsion changes from turbid to transparent to obtain microemulsion A; wherein, the molar concentration of silver nitrate solution is 0.07 mol / L and the mass ratio of n-octanol, ethanol and silver nitrate solution is 3:6:1;

[0048] (2) Mix n-octanol, ethanol and ascorbic acid solution at room temperature and stir. The emulsion changes from turbid to transparent to obtain microemulsion B. The molar concentration of ascorbic acid solution is 0.07 mol / L and the mass ratio of n-octanol, ethanol and ascorbic acid solution is 3:6:1.

[0049] (3) Microemulsion B was added to microemulsion A and allowed to stand at room temperature for 10 hours to obtain a solid precipitate. The supernatant was removed, and the silver powder was obtained after washing and drying. The mass ratio of microemulsion A to microemulsion B was 1:1.

[0050] Testing revealed that the silver powder prepared above had a particle size of 0.2–0.8 μm and a loose packing density of 1.7 g / cm³. 3 The tap density is 3.6 g / cm³. 3 .

[0051] Example 3

[0052] This invention provides a method for preparing ultrafine silver powder using a surfactant-free microemulsion, comprising the following steps:

[0053] (1) Mix n-octanol, ethanol and silver nitrate solution at room temperature and stir. The emulsion changes from turbid to transparent to obtain microemulsion A; wherein, the molar concentration of silver nitrate solution is 0.12 mol / L and the mass ratio of n-octanol, ethanol and silver nitrate solution is 3:4:3;

[0054] (2) Mix and stir n-octanol, ethanol and ascorbic acid solution at room temperature. The emulsion changes from turbid to transparent to obtain microemulsion B. The molar concentration of ascorbic acid solution is 0.12 mol / L and the mass ratio of n-octanol, ethanol and ascorbic acid solution is 3:4:3.

[0055] (3) Microemulsion B was added to microemulsion A and allowed to stand at room temperature for 10 hours to obtain a solid precipitate. The supernatant was removed, and the silver powder was obtained after washing and drying. The mass ratio of microemulsion A to microemulsion B was 1:1.

[0056] Testing revealed that the silver powder prepared above had a particle size of 0.2–0.8 μm and a loose packing density of 1.6 g / cm³. 3 The tap density is 3.6 g / cm³. 3 .

[0057] Example 4

[0058] This invention provides a method for preparing ultrafine silver powder using a surfactant-free microemulsion, comprising the following steps:

[0059] (1) Mix n-octanol, ethanol and silver nitrate solution at room temperature and stir. The emulsion changes from turbid to transparent to obtain microemulsion A; wherein, the molar concentration of silver nitrate solution is 0.1 mol / L and the mass ratio of n-octanol, ethanol and silver nitrate solution is 3:4:3;

[0060] (2) Mix and stir n-octanol, ethanol and ascorbic acid solution at room temperature. The emulsion changes from turbid to transparent to obtain microemulsion B. The molar concentration of ascorbic acid solution is 0.2 mol / L, and the mass ratio of n-octanol, ethanol and ascorbic acid solution is 3:4:3.

[0061] (3) Microemulsion B was added to microemulsion A and allowed to stand at room temperature for 10 hours to obtain a solid precipitate. The supernatant was removed, and the silver powder was obtained after washing and drying. The mass ratio of microemulsion A to microemulsion B was 1:2.

[0062] Testing revealed that the silver powder prepared above had a particle size of 0.2–0.4 μm and a loose packing density of 1.9 g / cm³. 3 The tap density is 3.7 g / cm³. 3 .

[0063] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing ultrafine silver powder using a surfactant-free microemulsion, characterized in that, Includes the following steps: (1) Mix n-octanol, ethanol and silver nitrate solution to obtain microemulsion A; (2) Mix n-octanol, ethanol, and ascorbic acid solution to obtain microemulsion B; (3) Mix microemulsion A and microemulsion B, let stand, and obtain silver powder; There is no order restriction between steps (1) and (2); In step (1), the mass ratio of n-octanol, ethanol, and silver nitrate solution is 3:4~6:1~3; In step (2), the mass ratio of n-octanol, ethanol, and ascorbic acid solution is 3:4~6:1~3; In step (3), the mass ratio of microemulsion A to microemulsion B is 1:1~3; In step (3), the particle size of the silver powder is 0.2~0.8μm; The molar concentration of the silver nitrate solution in step (1) is 0.05~0.12 mol / L; The molar concentration of the ascorbic acid solution in step (2) is 0.05~0.25 mol / L; The molar ratio of silver nitrate solution in step (1) to ascorbic acid solution in step (2) is 1:1~3.

Images