A method for preparing a highly dispersed platinum powder

Abstract

The application discloses a preparation method of high-dispersion platinum powder, and comprises the following steps: weighing a dispersing agent and dissolving the dispersing agent in deionized water in a reaction kettle to obtain a reaction bottom solution; preparing a platinum salt solution as an oxidant; preparing a reducing agent solution; preparing a sodium hydroxide solution with a corresponding mass fraction; subsequently, the three kinds of reagents are added into the reaction kettle at a set flow rate to perform a preparation reaction; after the reaction is completed, the solid-liquid phase is coated and centrifugally separated, and then drying is performed to obtain a final platinum powder product; and the platinum powder with a particle size in a range of 0-100 nm and high dispersion can be prepared without adding a crystal seed by changing the concentration of the sodium hydroxide and adjusting the drop flow rate.

Description

Technical Field

[0001] This invention belongs to the field of precious metal powder material preparation technology, and relates to a method for preparing highly dispersed platinum powder. Background Technology

[0002] Electronic pastes are the most fundamental functional materials in the electronics industry, and platinum powder, as the conductive phase in electronic pastes, possesses characteristics such as high conductivity and high performance. It is widely used in many fields, including aerospace, electronic computers, photovoltaics, and the civilian market, holding an extremely important position in the electronics, information, and energy sectors. Especially with the further development of the sensor industry, higher requirements are being placed on the performance indicators of platinum pastes for sensor circuits. As a key raw material for platinum pastes, the superiority of parameters such as particle size, morphology, particle size distribution, tap density, and surface condition of platinum powder has a significant impact on performance.

[0003] Currently, the general method for preparing platinum powder is the chemical reduction method. Because of its lower production cost and ease of control, the chemical reduction method is the primary method used for large-scale production. However, the platinum powder prepared by the mainstream chemical reduction method has a larger particle size, lower sphericity, and poor dispersibility. Furthermore, it is highly dependent on seed crystals, making it difficult to produce platinum powder with adjustable particle size and high dispersibility. Summary of the Invention

[0004] To address the aforementioned problems and shortcomings of existing platinum powder preparation technologies, this invention provides a method for preparing highly dispersible platinum powder that does not require the addition of seed crystals and has an adjustable particle size. By adjusting process parameters, the size of the platinum powder can be controlled, resulting in a platinum powder product with a narrow particle size distribution and good dispersibility. This preparation method is simple and controllable, has low production costs, and is easily scalable for large-scale production.

[0005] The technical solution adopted by this invention to solve its technical problem is: a method for preparing highly dispersed platinum powder, comprising the following steps:

[0006] Step 1: Add 0.5-6L of deionized water to the reaction vessel, weigh 20-300g of dispersant and dissolve it thoroughly as the reaction base liquid, prepare 0.5-5L of 100-200g / L platinum salt solution as the oxidant, prepare the reducing agent solution so that the molar ratio of metal ions to reducing agent is 1:0.6-1, and prepare 0.5-5L of 5-20% sodium hydroxide solution. The concentration of sodium hydroxide solution is adjusted by changing the amount of sodium hydroxide added.

[0007] Step 2: Heat the reactor to 25-65℃, and add the reaction base liquid, oxidant and reducing agent dropwise to the reactor at a flow rate of 5-100 mL / min to carry out the preparation reaction;

[0008] Step 3: After the reaction is complete, add a coating agent, then wash with deionized water and ethanol respectively, separate the solid and liquid phases, and dry in an oven to obtain the final platinum powder product with a D50 of 220-1000 nm.

[0009] The method for preparing highly dispersed platinum powder, wherein in step one, the dispersant is selected from one of gum arabic, polyethylene glycol, polyvinylpyrrolidone and methylcellulose, and the mass of the dispersant is 10% to 30% of the mass of the final platinum powder product.

[0010] The method for preparing highly dispersed platinum powder, wherein the reducing agent in step one is 500 mL of 60 g / L hydrazine hydrate solution, 500 mL of 100 g / L hydrazine sulfate solution, or 0.5–5 L of 80–160 g / L hydrazine hydrochloride solution.

[0011] In the method for preparing highly dispersed platinum powder, the temperature of the reactor in step two is adjusted by the temperature of the circulating water in the jacket.

[0012] In the preparation method of highly dispersed platinum powder, the dropping speed of the raw material in step two is adjusted by the rotation speed of a peristaltic pump or a metering pump.

[0013] In the preparation method of highly dispersed platinum powder, the coating agent in step three is lauric acid, palmitic acid, oleic acid or fatty acid, and the mass of the coating agent is 0.1% to 1% of the mass of the final platinum powder product.

[0014] In the method for preparing highly dispersed platinum powder, the drying temperature in step three is controlled at 45–70 °C.

[0015] The advantages and positive effects of this invention are as follows:

[0016] 1. The method of the present invention achieves the purpose of generating ultrafine nano-platinum powder in the reaction solution without adding seed crystals by controlling the amount of sodium hydroxide added and utilizing the principle that the reducing agent has different reducing power under different acidity and alkalinity.

[0017] 2. The method of the present invention reduces the probability of collisions between platinum particles by controlling the rate at which the dispersant and platinum ions are reduced, thus effectively solving the dispersion problem of platinum powder in the preparation process.

[0018] 3. The method of the present invention can control the particle size of the final platinum powder by adjusting the dropping flow rate, thus avoiding cumbersome operation and material preparation problems;

[0019] 4. The raw materials used in the production and preparation of this type of platinum powder by the method of the present invention are inexpensive, and the waste liquid treatment is relatively simple, which can bring considerable economic benefits to enterprises. Attached Figure Description

[0020] Figure 1SEM image of the highly dispersed platinum powder prepared in Example 1;

[0021] Figure 2 SEM image of the highly dispersed platinum powder prepared in Example 2;

[0022] Figure 3 SEM image of the highly dispersed platinum powder prepared in Example 3;

[0023] Figure 4 The image shows a SEM image of the highly dispersed platinum powder prepared in Example 4. Detailed Implementation

[0024] The present invention will be specifically described below through embodiments. These embodiments are for further explanation of the present invention and should not be construed as limiting the scope of protection of the present invention. Example 1

[0025] This embodiment discloses a method for preparing highly dispersed platinum powder, which includes the following steps.

[0026] Step 1: Add 500 mL of deionized water to the reaction vessel, weigh 20 g of gum arabic powder and dissolve it completely as the reaction base liquid, prepare 500 mL of 100 g / L platinum salt solution as the oxidant, prepare 500 mL of 60 g / L hydrazine hydrate solution as the reducing agent, and prepare 500 mL of 20% sodium hydroxide solution.

[0027] Step 2: The reactor is heated to 65 °C, and the three reagents are added dropwise to the reactor at a flow rate of 20 mL / min to carry out the preparation reaction. The temperature of the reactor is regulated by circulating water in the jacket and the speed is regulated by a peristaltic pump or metering pump.

[0028] Step 3: After the reaction is complete, add the coating agent palmitic acid, then wash with deionized water and ethanol respectively, separate the solid and liquid phases, and dry in an oven at 45-70 °C to obtain the final platinum powder product.

[0029] Using SEM electron microscopy, such as Figure 1 The analysis showed that the D50 of the obtained platinum powder was 220 nm. Example 2

[0030] This embodiment discloses a method for preparing highly dispersed platinum powder, which includes the following steps.

[0031] Step 1: Add 500 mL of deionized water to the reaction vessel, weigh 20 g of polyethylene glycol dispersant and dissolve it completely as the reaction base liquid, prepare 500 mL of 100 g / L platinum salt solution as the oxidant, prepare 500 mL of 100 g / L hydrazine sulfate solution as the reducing agent, and prepare 500 mL of 5% sodium hydroxide solution.

[0032] Step 2: Heat the reactor to 25 °C, and add the three reagents dropwise to the reactor at a flow rate of 5 mL / min to carry out the preparation reaction. Adjust the speed using a peristaltic pump or metering pump.

[0033] Step 3: After the reaction is complete, add the coating agent oleic acid, then wash with deionized water and ethanol respectively, separate the solid and liquid phases, and dry in an oven at 45-70 °C to obtain the final platinum powder product.

[0034] Using SEM electron microscopy, such as Figure 2 The analysis shown indicates that the D50 of the obtained platinum powder is 1000 nm. Example 3

[0035] This embodiment discloses a method for preparing highly dispersed platinum powder, which includes the following steps.

[0036] Step 1: Add 500 mL of deionized water to the reaction vessel, weigh 20 g of polyvinylpyrrolidone dispersant and dissolve it completely as the reaction base liquid, prepare 500 mL of 100 g / L platinum salt solution as the oxidant, prepare 500 mL of 80 g / L hydrazine hydrochloride solution as the reducing agent, and prepare 500 mL of 10% sodium hydroxide solution.

[0037] Step 2: Heat the reactor to 45 °C, and add the three reagents dropwise to the reactor at a flow rate of 15 mL / min to carry out the preparation reaction. Adjust the speed using a peristaltic pump or metering pump.

[0038] Step 3: After the reaction is complete, add the coating agent lauric acid, then wash with deionized water and ethanol respectively, separate the solid and liquid phases, and dry in an oven at 45-70 °C to obtain the final platinum powder product.

[0039] Using SEM electron microscopy, such as Figure 3 The analysis shown indicates that the D50 of the obtained platinum powder is 650 nm. Example 4

[0040] This embodiment discloses a method for preparing highly dispersed platinum powder, which includes the following steps.

[0041] Step 1: Add 6 L of deionized water to the reaction vessel, weigh 300 g of methylcellulose dispersant and dissolve it completely as the reaction base liquid, prepare 5 L of 200 g / L platinum salt solution as the oxidant, prepare 5 L of 160 g / L hydrazine hydrochloride solution as the reducing agent, and prepare 5 L of 10% sodium hydroxide solution.

[0042] Step 2: Heat the reactor to 45 ℃, and add the three reagents dropwise to the reactor at a flow rate of 100 mL / min to carry out the preparation reaction. Adjust the speed using a peristaltic pump or metering pump.

[0043] Step 3: After the reaction is complete, add the coating agent fatty acid, then wash with deionized water and ethanol respectively, separate the solid and liquid phases, and dry in an oven at 45-70 °C to obtain the final platinum powder product.

[0044] Using SEM electron microscopy, such as Figure 4 The analysis shown indicates that the D50 of the obtained platinum powder is 600 nm.

[0045] The technical content and features of the present invention are as described above, but the scope of protection of the present invention should not be limited to the content described in the embodiments, but should include various substitutions and modifications that do not depart from the present invention, and are covered by the claims of this patent application.

Claims

1. A method for preparing highly dispersed platinum powder, characterized in that: Includes the following steps Step 1: Add 0.5–6 L of deionized water to the reaction vessel. Weigh 20–300 g of dispersant and dissolve it thoroughly as the reaction base liquid. The dispersant is one of gum arabic, polyethylene glycol, and methylcellulose. Prepare 0.5–5 L of a 100–200 g / L platinum salt solution as the oxidant. Prepare a reducing agent solution such that the molar ratio of metal ions to reducing agent is 1:0.6–1. The reducing agent is 500 mL of a 100 g / L hydrazine sulfate solution or 0.5–5 L of an 80–160 g / L hydrazine hydrochloride solution. Prepare 0.5–5 L of a 5–20% (w / w) sodium hydroxide solution. Step 2: Heat the reactor to 25-65°C, and add sodium hydroxide solution, oxidant and reducing agent dropwise to the reactor at a flow rate of 5-100 mL / min to carry out the preparation reaction; Step 3: After the reaction is complete, add lauric acid, palmitic acid, oleic acid or fatty acid as coating agents, then wash with deionized water and ethanol respectively, separate the solid and liquid phases, and dry in an oven to obtain the final platinum powder product.

2. The method for preparing highly dispersed platinum powder according to claim 1, characterized in that, In step two, the temperature of the reactor is regulated by circulating water in the jacket.

3. The method for preparing highly dispersed platinum powder according to claim 1, characterized in that, The dripping speed in step two is adjusted by the rotation speed of a peristaltic pump or a metering pump.

4. The method for preparing highly dispersed platinum powder according to claim 1, characterized in that, The drying temperature in step three is controlled at 45–70 °C.

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