CN104477976A - Preparation method of calcium titanate powder with controllable micro/nano structures - Google Patents

Abstract

The invention relates to a preparation method of calcium titanate powder with controllable micro/nano structures, which comprises the following steps: preparing a titanium precursor gel; preparing a calcium salt-graphene oxide mixed solution; mixing the titanium precursor gel and the mixed solution to obtain a suspension; and adding a potassium hydroxide water solution into the suspension, and carrying out hydrothermal reaction with a reaction kettle. The preparation method is simple to operate, and can obtain the calcium titanate powder with different micro/nano structures by regulating the alkali concentration; and the product has the advantages of higher purity, higher crystallinity and favorable dispersity.

Description

Preparation method of calcium titanate powder with controllable micro-nano structure

technical field

The invention relates to a preparation method of calcium titanate powder with a controllable micro-nano structure, and belongs to the technical field of inorganic non-metallic materials.

Background technique

With the rapid development of science and technology and the rapid improvement of people's living standards, although the sharp increase in the use of family cars has brought huge benefits to the economy, it also poses a threat to people's travel safety. According to the statistics of Safety Culture Network, every 5 minutes in China, one person is injured or dies due to a car accident. Such a large number of patients is a severe test for the development of bone clinical medicine in our country. At present, the bone substitutes used in hospitals are basically titanium alloys. In order to make them more biocompatible, research on the surface modification of titanium alloys has become very important. Imitating the composition of the skeleton of a living body, the modification material is generally calcium phosphate.

Perovskite-type materials have attracted extensive attention from researchers due to their structural stability and element flexibility. With the emergence of perovskite-type materials with various new element compositions or new morphology structures, their applications have changed from traditional to The functional electronic materials have expanded to many fields such as semiconductor light-emitting materials, hybrid solar cells, and photocatalytic materials. As a perovskite material, calcium titanate has the potential to be a surface modification material for titanium alloys, but there are few studies on its preparation and properties.

Contents of the invention

The object of the present invention is to provide a method for preparing calcium titanate powder with controllable micro-nano structure, low cost, high product purity and easy operation.

The preparation method of calcium titanate powder with controllable micro-nano structure of the present invention comprises the following steps:

1) Dissolve tetrabutyl titanate in ethylene glycol methyl ether, prepare tetrabutyl titanate ethylene glycol methyl ether solution with a concentration of 1~2.5mmol/mL, and add ammonia water dropwise under stirring to form a condensate Gel, the resulting gel is washed to neutral with deionized water to obtain a titanium precursor gel;

2) Dissolve an equimolar amount of calcium nitrate tetrahydrate in step 1) in deionized water to prepare an aqueous solution of calcium nitrate tetrahydrate with a concentration of 0.5-1 mmol/mL;

3) Under stirring, add graphene oxide aqueous solution to the aqueous solution of calcium nitrate tetrahydrate obtained in step 2), and the molar ratio of graphene oxide to calcium nitrate tetrahydrate is 1:120 to obtain a mixed solution;

4) Under stirring, add the titanium precursor gel obtained in step 1) to the mixed solution obtained in step 3) to obtain a suspension;

5) Add potassium hydroxide aqueous solution to the suspension obtained in step 4), so that the molar ratio of potassium hydroxide to calcium nitrate tetrahydrate is 7:1~22:1;

6) Add the suspension in step 5) into the inner tank of the reactor, adjust the liquid volume in the inner tank of the reactor with deionized water to 4/5~7/8 of the volume of the inner tank, and place the inner tank of the reactor in the reaction In the kettle, keep warm at 120°C for 10h, then cool to room temperature naturally, wash the obtained product with deionized water until neutral, then wash with absolute ethanol, and dry at 60-80°C.

The purity of tetrabutyl titanate (TBOT), ammonia water, ethylene glycol methyl ether, calcium nitrate tetrahydrate, graphene oxide solution and potassium hydroxide described in the present invention is not lower than chemical purity. The reaction kettle is a polytetrafluoroethylene liner and a closed reaction kettle made of stainless steel.

The present invention obtains calcium titanate powders with different micro-nano structures through a hydrothermal method. In the present invention, the adjustment of the alkali concentration in the reaction system has a decisive effect on the structure and morphology of the product, and the graphene oxide has an influence on the size of the product, and promotes the growth of the calcium titanate micro-sheets forming the micro-nano structure. The preparation method has simple operation, high product purity and crystallinity, and good dispersibility.

Description of drawings

Fig. 1 is the X-ray diffraction pattern of gained calcium titanate micro-nano structure when adding 4g potassium hydroxide;

Fig. 2 is the scanning electron micrograph of gained calcium titanate micro-nano structure when adding 4g potassium hydroxide;

Fig. 3 is the X-ray diffraction pattern of gained calcium titanate micro-nano structure when adding 6g potassium hydroxide;

Figure 4 is a scanning electron micrograph of the calcium titanate micro-nano structure obtained when 6g of potassium hydroxide is added.

Specific implementation method

Below in conjunction with embodiment further illustrate the inventive method

Example 1

1) Dissolve 5mmol tetrabutyl titanate in 2mL ethylene glycol methyl ether, add ammonia water dropwise under stirring to form a gel, wash the resulting gel with deionized water until neutral, and obtain a titanium precursor gel;

2) Dissolve 5 mmol of calcium nitrate tetrahydrate in 10 mL of deionized water to obtain an aqueous solution of calcium nitrate tetrahydrate;

3) Under stirring, add 10 mL of graphene oxide aqueous solution with a concentration of 0.05 mg/mL to the aqueous solution of calcium nitrate tetrahydrate obtained in step 2);

4) Under stirring, add the titanium precursor gel obtained in step 1) to the mixed solution obtained in step 3) to obtain a suspension;

5) Add 5 mL of an aqueous solution containing 2 g of potassium hydroxide to the suspension obtained in step 4);

6) Add the suspension in step 5) into the inner tank of the reactor, adjust the liquid volume in the inner tank of the reactor to 4/5 of the volume of the inner tank with deionized water, place the inner tank of the reactor in the reactor, and After heat preservation at 120°C for 10 hours, cool naturally to room temperature, wash the obtained product with deionized water until neutral, then wash twice with absolute ethanol, and dry at 70°C to obtain cubic calcium titanate with some steps. The average size of this micro-nano structure is about 5 μm.

Example 2

1) Dissolve 5mmol tetrabutyl titanate in 3mL ethylene glycol methyl ether, add ammonia water dropwise under stirring to form a gel, wash the resulting gel with deionized water until neutral, and obtain a titanium precursor gel;

2) Dissolve 5 mmol of calcium nitrate tetrahydrate in 8 mL of deionized water to obtain an aqueous solution of calcium nitrate tetrahydrate;

3) Under stirring, add 10 mL of graphene oxide aqueous solution with a concentration of 0.05 mg/mL to the aqueous solution of calcium nitrate tetrahydrate obtained in step 2);

4) Under stirring, add the titanium precursor gel obtained in step 1) to the mixed solution obtained in step 3) to obtain a suspension;

5) Add 8 mL of an aqueous solution containing 4 g of potassium hydroxide to the suspension obtained in step 4);

6) Add the suspension in step 5) into the inner tank of the reactor, adjust the liquid volume in the inner tank of the reactor to 4/5 of the volume of the inner tank with deionized water, place the inner tank of the reactor in the reactor, and After being kept at 120°C for 10 hours, it was naturally cooled to room temperature, and the obtained product was washed with deionized water to neutrality, then washed twice with absolute ethanol, and dried at 70°C to obtain a multi-step cube as shown in Figure 2. The average size of this micro-nano structure is about 3 μm, and it is composed of sheets with a length and width of 1-2 μm. Its XRD pattern is shown in Figure 1, and each peak has a corresponding crystal orientation, indicating that the prepared calcium titanate has good purity and crystallinity. In addition, the analysis found that the peak shifted to a small angle, indicating that the addition of graphene caused the lattice constant of calcium titanate to increase.

Example 3

1) Dissolve 5mmol tetrabutyl titanate in 5mL ethylene glycol methyl ether, add ammonia water dropwise under stirring to form a gel, wash the resulting gel with deionized water until neutral, and obtain a titanium precursor gel;

2) Dissolve 5 mmol of calcium nitrate tetrahydrate in 5 mL of deionized water to obtain an aqueous solution of calcium nitrate tetrahydrate;

3) Under stirring, add 10 mL of graphene oxide aqueous solution with a concentration of 0.05 mg/mL to the aqueous solution of calcium nitrate tetrahydrate obtained in step 2);

4) Under stirring, add the titanium precursor gel obtained in step 1) to the mixed solution obtained in step 3) to obtain a suspension;

5) Add 10 mL of an aqueous solution containing 6 g of potassium hydroxide to the suspension obtained in step 4);

6) Add the suspension in step 5) into the inner tank of the reactor, adjust the liquid volume in the inner tank of the reactor to 7/8 of the volume of the inner tank with deionized water, place the inner tank of the reactor in the reactor, and After heat preservation at 120°C for 10 hours, cool naturally to room temperature, wash the obtained product with deionized water until neutral, then wash twice with absolute ethanol, and dry at 70°C to obtain the titanium alloy in the shape of an airplane as shown in Figure 4. Calcium acid, the size of this micro-nano structure is 3-5 μm, and it is composed of sheets with a size of about 1 μm. Its XRD pattern is shown in Figure 3, indicating that the prepared calcium titanate has good purity and crystallinity.

Claims (3)

1. The preparation method of the calcium titanate powder with controllable micro-nano structure comprises the following steps: 1) Dissolve tetrabutyl titanate in ethylene glycol methyl ether, prepare tetrabutyl titanate ethylene glycol methyl ether solution with a concentration of 1~2.5mmol/mL, and add ammonia water dropwise under stirring to form a condensate Gel, the resulting gel is washed to neutral with deionized water to obtain a titanium precursor gel; 2) Dissolve an equimolar amount of calcium nitrate tetrahydrate in step 1) in deionized water to prepare an aqueous solution of calcium nitrate tetrahydrate with a concentration of 0.5-1 mmol/mL; 3) Under stirring, add graphene oxide aqueous solution to the aqueous solution of calcium nitrate tetrahydrate obtained in step 2), and the molar ratio of graphene oxide to calcium nitrate tetrahydrate is 1:120 to obtain a mixed solution; 4) Under stirring, add the titanium precursor gel obtained in step 1) to the mixed solution obtained in step 3) to obtain a suspension; 5) Add potassium hydroxide aqueous solution to the suspension obtained in step 4), so that the molar ratio of potassium hydroxide to calcium nitrate tetrahydrate is 7:1~22:1; 6) Add the suspension in step 5) into the inner tank of the reactor, adjust the liquid volume in the inner tank of the reactor with deionized water to 4/5~7/8 of the volume of the inner tank, and place the inner tank of the reactor in the reaction In the kettle, keep warm at 120°C for 10h, then cool to room temperature naturally, wash the obtained product with deionized water until neutral, then wash with absolute ethanol, and dry at 60-80°C. 2. according to the preparation method of the calcium titanate powder with controllable micro-nano structure according to claim 1, it is characterized in that said reaction kettle is a polytetrafluoroethylene liner, a stainless steel sleeve airtight reaction kettle. 3. the preparation method of the calcium titanate powder with controllable micro-nano structure according to claim 1 is characterized in that said tetrabutyl titanate, ammoniacal liquor, ethylene glycol methyl ether, calcium nitrate tetrahydrate, The purity of graphene oxide solution and potassium hydroxide is not lower than chemical purity.